WO2010119732A1 - Polarizer protective film, polarizing plate using same and method for production thereof - Google Patents

Polarizer protective film, polarizing plate using same and method for production thereof Download PDF

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Publication number
WO2010119732A1
WO2010119732A1 PCT/JP2010/053288 JP2010053288W WO2010119732A1 WO 2010119732 A1 WO2010119732 A1 WO 2010119732A1 JP 2010053288 W JP2010053288 W JP 2010053288W WO 2010119732 A1 WO2010119732 A1 WO 2010119732A1
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Prior art keywords
film
acid
roll
polarizer protective
protective film
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PCT/JP2010/053288
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French (fr)
Japanese (ja)
Inventor
康志 入江
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コニカミノルタオプト株式会社
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Priority to JP2011509241A priority Critical patent/JPWO2010119732A1/en
Publication of WO2010119732A1 publication Critical patent/WO2010119732A1/en

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C08L33/04—Homopolymers or copolymers of esters
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2301/00—Characterised by the use of cellulose, modified cellulose or cellulose derivatives
    • C08J2301/08—Cellulose derivatives
    • C08J2301/10—Esters of organic acids
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2333/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers
    • C08J2333/04—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers esters
    • C08J2333/06—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers esters of esters containing only carbon, hydrogen, and oxygen, the oxygen atom being present only as part of the carboxyl radical

Definitions

  • the present invention relates to a polarizer protective film with improved suitability for saponification treatment. More specifically, the wound shape of a roll after saponification is good, and it is suitable for speeding up the saponification treatment process, and further durable.
  • the present invention relates to a polarizer protective film capable of producing an excellent polarizing plate. Moreover, it is related with the polarizing plate using the said polarizer protective film, and its manufacturing method.
  • liquid crystal display devices can be used as a large display installed on a street or in a store, or used as an advertising display in a public place using a display device called digital signage.
  • PMMA polymethyl methacrylate
  • the PMMA film when compared with a cellulose ester film or the like, is fragile and brittle, and is difficult to handle. In particular, it is difficult to stably produce a polarizer protective film for a large liquid crystal display device. It was.
  • Patent Document 1 proposes an optical film made of a resin composition made of a blend of an acrylic resin and a cellulose derivative.
  • the optical film made of this blended resin composition is a polarizer protective film that has good transparency, durability under high temperature and high humidity, and excellent brittleness. Adhesion with the polarizer required a special adhesive different from the polyvinyl alcohol-based aqueous adhesive used for the cellulose ester film, which is a normal polarizer protective film, and was greatly inferior in terms of production of polarizing plates. .
  • the present invention has been made in view of the above problems, and the solution is excellent in saponification suitability, in particular, the adhesiveness of the polarizer is not impaired even in the rapid processing of saponification, and the roll shape of the film Is to provide a polarizer protective film that is stable and excellent in image unevenness. Moreover, it is providing the polarizing plate using the said polarizer protective film, and its manufacturing method.
  • the polarizer protective film characterized by being small with respect to.
  • a polarizing plate comprising a polarizer and two polarizer protective films sandwiching the polarizer, wherein at least one of the polarizer protective films is in any one of items 1 to 4 above.
  • a polarizing plate comprising the polarizer protective film according to claim.
  • the polarizing plate using the said polarizer protective film and its manufacturing method can be provided.
  • the polarizer protective film of the present invention (hereinafter also referred to as “optical film” or simply “film” as appropriate) is a polarizer protective film containing an acrylic resin (A) and a cellulose ester resin (B).
  • A acrylic resin
  • B cellulose ester resin
  • the surface state of the polarizer protective film after saponification is extremely important, and specifically, it is necessary to increase the unevenness of the surface state.
  • a method of adding fine particles a method of forming fine cracks on the surface by adjusting the draw ratio and the drawing speed, and further pressing the roll having fine unevenness on the surface to make unevenness on the film
  • Examples include a method of transferring.
  • additives such as a compound which has hydrophilic property, and a preferable plasticizer.
  • in order to suppress the inhibition of adhesiveness over time due to the residue generated by the saponification reaction it is also achieved by an appropriate substitution degree and molecular weight of the cellulose ester and a preferable ratio with the acrylic resin.
  • the acrylic resin (A) and the cellulose ester resin (B) are contained in a mass ratio of 85:15 to 30:70 and fine particles are included from the viewpoint of manifesting the effects of the present invention. It is preferable to do. Further, it is preferable that the fine particles contain inorganic fine particles, or an aspect containing inorganic fine particles and acrylic particles.
  • the polarizer protective film of the present invention is used for a polarizing plate, in the polarizing plate including the polarizer and the two polarizer protective films sandwiching the polarizer, at least one of the polarizer protective films is of the present invention. It is preferable that it is a polarizer protective film.
  • the production method of the polarizing plate for producing the polarizing plate is preferably a production method having a step of saponifying the polarizer protective film of the present invention.
  • the saponification treatment is performed within 180 seconds from saponification to washing immediately before drying.
  • the “saponification treatment” as used in the present application refers to a chemical treatment in which an ester is decomposed into an acid salt and an alcohol by adding an alkali in order to decompose the ester structure portion of the film into the original constituent acid and alcohol.
  • saponification treatment various conventionally known saponification treatment methods can be adopted, but a method based on the following method is preferred.
  • the alkaline solution is preferably a potassium hydroxide aqueous solution or a sodium hydroxide aqueous solution.
  • a preferred concentration is 0.5 to 3 mol / L, particularly preferably 1 to 2.5 mol / L.
  • the liquid temperature of the alkaline solution is preferably 30 to 75 ° C, particularly preferably 35 to 60 ° C.
  • a preferable immersion time is 20 seconds to 300 seconds, particularly preferably 30 to 100 seconds.
  • the combination of the saponification conditions is preferably a combination of relatively mild conditions, but can be set according to the material and configuration of the light scattering film and the antireflection film, and the target contact angle.
  • the hydrophilized surface is effective for improving the adhesion with an adhesive layer mainly composed of polyvinyl alcohol.
  • the film of the present invention has a range of 10 to 55 degrees from the viewpoint of adhesion to the polarizing film, physical strength, and the like. Preferably there is. Further, it is preferably 30 to 50 degrees, and particularly preferably in the range of 40 to 50 degrees.
  • the alkali solution functions as an antiglare layer or a low refractive index layer under appropriate conditions.
  • An alkaline liquid coating method in which coating, heating, washing and drying are performed only on the surface opposite to the surface having the layer is preferable.
  • the application in this case means that an alkaline liquid or the like is brought into contact only with the surface to be saponified, and is performed by spraying or contacting a belt containing the liquid in addition to the application. Including.
  • a separate facility and process for applying an alkaline solution are required, which is inferior to the immersion method (1) from the viewpoint of cost.
  • the opposite surface can have a layer using a material that is weak against the alkali solution.
  • vapor deposition films and sol-gel films have various effects such as corrosion, dissolution, and peeling due to alkali solution, so it is not desirable to use the immersion method. Is possible.
  • each layer can be formed after being unwound from a roll-shaped support, it can be carried out by a series of operations in addition to the film manufacturing process. Good. Furthermore, the polarizing plate can be produced more efficiently than the same operation with a single wafer by continuously performing the pasting step with the polarizing plate comprising the support that has been unwound in the same manner.
  • the present invention is most characterized in that the coefficient of friction after saponification is smaller than the coefficient of friction before saponification, which indicates that it is effective to increase the adhesion area by forming irregularities on the surface. I believe that. Similarly, it is considered that the presence of fine particles at the interface between the polarizer and the film provides a more preferable environment. As described above, a design that increases the unevenness of the film surface after saponification can be effective.
  • the coefficient of friction between the contact surfaces of the film is measured by the method defined in JIS-K-7125 (1987).
  • the acrylic resin used in the present invention includes a methacrylic resin.
  • the resin is not particularly limited, but a resin comprising 50 to 99% by mass of methyl methacrylate units and 1 to 50% by mass of other monomer units copolymerizable therewith is preferable.
  • Examples of other copolymerizable monomers include alkyl methacrylates having 2 to 18 alkyl carbon atoms, alkyl acrylates having 1 to 18 carbon atoms, alkyl acrylates such as acrylic acid and methacrylic acid.
  • Unsaturated group-containing divalent carboxylic acids such as saturated acid, maleic acid, fumaric acid and itaconic acid, aromatic vinyl compounds such as styrene and ⁇ -methylstyrene, ⁇ , ⁇ -unsaturated nitriles such as acrylonitrile and methacrylonitrile, Examples thereof include maleic anhydride, maleimide, N-substituted maleimide, glutaric anhydride, and acrylamide derivatives such as acryloylmorpholine. These may be used alone or in combination of two or more monomers.
  • methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, 2-ethylhexyl acrylate, and the like are preferable from the viewpoint of thermal decomposition resistance and fluidity of the copolymer.
  • n-Butyl acrylate is particularly preferably used.
  • the weight average molecular weight (Mw) of the acrylic resin (A) used in the film of the present invention is preferably in the range of 110,000 to 1,000,000, and in the range of 140,000 to 600,000. More preferably, it is particularly preferably in the range of 200,000 to 400,000.
  • the weight average molecular weight of the acrylic resin according to the present invention can be measured by gel permeation chromatography.
  • the measurement conditions are as follows.
  • the production method of the acrylic resin (A) in the present invention is not particularly limited, and any known method such as suspension polymerization, emulsion polymerization, bulk polymerization, or solution polymerization may be used.
  • a polymerization initiator a normal peroxide type, azo type, or redox type can be used.
  • the polymerization temperature may be 30 to 100 ° C. for suspension or emulsion polymerization, and 80 to 160 ° C. for bulk or solution polymerization.
  • polymerization can be carried out using alkyl mercaptan or the like as a chain transfer agent.
  • acrylic resins can be used as the acrylic resin according to the present invention.
  • Delpet 60N, 80N (Asahi Kasei Chemicals Co., Ltd.), Dialal BR52, BR80, BR83, BR85, BR88 (Mitsubishi Rayon Co., Ltd.), KT75 (Electrochemical Industry Co., Ltd.) and the like can be mentioned.
  • Two or more acrylic resins can be used in combination.
  • the cellulose ester resin (B) according to the present invention has a total acyl group substitution degree (T) of 2.0 to 3 particularly from the viewpoint of improvement in brittleness and transparency when it is compatible with the acrylic resin (A).
  • the substitution degree of the acyl group having 0.0 and 3 to 7 carbon atoms is preferably 1.2 to 3.0, more preferably the total substitution degree of the acyl group is 2.5 to 3.0 and 3 carbon atoms.
  • the substitution degree of the acyl group of ⁇ 7 is 2.0 to 3.0.
  • the acrylic resin (A) and the cellulose ester resin (B) are not sufficiently compatible with each other and used as an acrylic film. May be a problem.
  • the total substitution degree of the acyl group is 2.0 or more, if the substitution degree of the acyl group having 3 to 7 carbon atoms is less than 1.2, still sufficient compatibility cannot be obtained, Brittleness will decrease.
  • the acyl group may be an aliphatic acyl group or an aromatic acyl group.
  • an aliphatic acyl group it may be linear or branched and may further have a substituent.
  • the portion that is not substituted with an acyl group usually exists as a hydroxyl group.
  • the cellulose ester resin (B) according to the present invention is preferably at least one selected from cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate benzoate, cellulose propionate, and cellulose butyrate.
  • cellulose ester resins that are particularly preferable are cellulose acetate propionate and cellulose propionate.
  • substitution degree of the acetyl group and the substitution degree of other acyl groups were determined by the method prescribed in ASTM-D817-96.
  • the weight average molecular weight (Mw) of the cellulose ester resin according to the present invention is preferably 75,000 or more, particularly from the viewpoint of improvement in compatibility with the acrylic resin (A) and brittleness, and 75,000 to 240,000. Is more preferably in the range of 100,000 to 240,000, particularly preferably 160,000 to 240,000. In the present invention, two or more kinds of cellulose resins can be mixed and used.
  • the acrylic resin (A) and the cellulose ester resin (B) are preferably used in a mass ratio of 85:15 to 30:70, more preferably from the viewpoint of manifesting the effects of the present invention. 80:20 to 40:60, most preferably 80:20 to 50:50.
  • the acrylic resin (A) and the cellulose ester resin (B) are preferably contained in a compatible state.
  • the physical properties and quality required for an optical film are achieved by supplementing each other by dissolving different resins.
  • Whether the acrylic resin (A) and the cellulose ester resin (B) are in a compatible state can be determined by, for example, the glass transition temperature Tg.
  • the two resins have different glass transition temperatures
  • there are two or more glass transition temperatures for each resin because there is a glass transition temperature for each resin.
  • the glass transition temperature specific to each resin disappears and becomes one glass transition temperature, which is the glass transition temperature of the compatible resin.
  • the glass transition temperature referred to here is an intermediate value determined according to JIS K7121 (1987) using a differential scanning calorimeter (DSC-7 model manufactured by Perkin Elmer) at a heating rate of 20 ° C./min.
  • the point glass transition temperature (Tmg) is an intermediate value determined according to JIS K7121 (1987) using a differential scanning calorimeter (DSC-7 model manufactured by Perkin Elmer) at a heating rate of 20 ° C./min.
  • the point glass transition temperature (Tmg) The point glass transition temperature (Tmg).
  • the film of the present invention may contain resins and additives other than the acrylic resin (A) and the cellulose ester resin (B) as long as the effects of the present invention are not impaired.
  • fine particles are preferably used for improving the adhesion between the polarizer and the polarizer protective film.
  • the fine particles used in the present invention may be either inorganic fine particles or organic fine particles.
  • organic fine particles for example, polymers such as silicone resin, fluororesin and acrylic resin are preferable, and acrylic particles are preferably used.
  • inorganic fine particles that are excellent in the wound shape after saponification and enable long winding are preferably used, but the combined use of inorganic fine particles and organic fine particles is most preferable because the adhesiveness of the polarizing plate becomes stronger.
  • Inorganic fine particles include silicon-containing compounds, silicon dioxide, aluminum oxide, zirconium oxide, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, calcium phosphate, etc. More preferred are inorganic fine particles containing silicon and zirconium oxide.
  • silicon dioxide is particularly preferably used since it has a refractive index close to that of cellulose ester and is excellent in transparency (haze).
  • Specific examples of silicon dioxide include Aerosil 200V, Aerosil R972V, Aerosil R972, R974, R812, 200, 300, R202, OX50, TT600 (above Nippon Aerosil Co., Ltd.), Sea Hoster KEP-10, Sea Hoster KEP-30, Product names such as Seahoster KEP-50, Seahoster KE-P100 (above, Nippon Shokubai Co., Ltd.), Silo Hovic 100 (Fuji Silysia), Nip Seal E220A (Nihon Silica Kogyo), Admafine SO (Admatechs) A commercially available product having the above can be preferably used.
  • the shape of the inorganic fine particles can be used without particular limitation, such as indefinite shape, needle shape, flat shape, spherical shape, etc.
  • the use of spherical particles is particularly preferable because the transparency of the resulting film can be improved.
  • the particle size is preferably smaller than the wavelength of visible light, and more preferably 1 ⁇ 2 or less of the wavelength of visible light. .
  • the particle size is preferably in the range of 0.05 ⁇ m to 3.0 ⁇ m.
  • These fine particles can be used alone or in combination of two or more. By using particles having different particle sizes and shapes (for example, acicular and spherical), both transparency and slipperiness can be made highly compatible. These fine particles can be contained in an amount of 0.01 to 5% by mass of the entire optical film.
  • the particle size means the size of the aggregate when the particle is an aggregate of primary particles. Moreover, when a particle is not spherical, it means the diameter of a circle corresponding to the projected area.
  • the acrylic particles according to the present invention are characterized by being present in the state of particles in the acrylic resin (A), the cellulose ester resin (B) and the acrylic resin-containing film (also referred to as incompatible state).
  • the acrylic particles are obtained by, for example, collecting a predetermined amount of the prepared acrylic resin-containing film, dissolving in a solvent, stirring, and sufficiently dissolving and dispersing the PTFE film having a pore diameter less than the average particle diameter of the acrylic particles. It is preferable that the weight of the insoluble matter filtered and collected using the membrane filter is 90% by mass or more of the acrylic particles added to the acrylic resin-containing film.
  • the acrylic particles used in the present invention are not particularly limited, but are preferably acrylic particles having a layer structure of two or more layers, and particularly preferably the following multilayer structure acrylic granular composite.
  • the multilayer structure acrylic granular composite is formed by laminating an innermost hard layer polymer, a cross-linked soft layer polymer exhibiting rubber elasticity, and an outermost hard layer polymer from the center to the outer periphery.
  • Preferred embodiments of the multilayer structure acrylic granular composite used in the acrylic resin composition according to the present invention include the following.
  • (c) the innermost hard In the presence of a polymer comprising a layer and a crosslinked soft layer, a monomer mixture comprising 80 to 99% by mass of methyl methacrylate and 1 to 20% by
  • Outermost hard layer weight And the obtained three-layer structure polymer is an innermost hard layer polymer (a) 5 to 40% by mass, a soft layer polymer (b) 30 to 60% by mass, and An outermost hard layer polymer (c) comprising 20 to 50% by mass, having an insoluble part when fractionated with acetone, and an acrylic granular composite having a methyl ethyl ketone swelling degree of 1.5 to 4.0 at the insoluble part .
  • the innermost hard layer polymer (a) constituting the multilayer structure acrylic granular composite is 80 to 98.9% by mass of methyl methacrylate and 1 to 20 mass of alkyl acrylate having 1 to 8 carbon atoms in the alkyl group. % And a monomer mixture consisting of 0.01 to 0.3% by mass of a polyfunctional grafting agent is preferred.
  • examples of the alkyl acrylate having 1 to 8 carbon atoms in the alkyl group include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, 2-ethylhexyl acrylate, and the like. And n-butyl acrylate are preferably used.
  • the proportion of the alkyl acrylate unit in the innermost hard layer polymer (a) is 1 to 20% by mass.
  • the thermal decomposability of the polymer is increased, while the unit is 20% by mass. If it exceeds 50%, the glass transition temperature of the innermost hard layer polymer (c) is lowered, and the impact resistance imparting effect of the three-layer structure acrylic granular composite is lowered.
  • polyfunctional grafting agent examples include polyfunctional monomers having different polymerizable functional groups, such as allyl esters of acrylic acid, methacrylic acid, maleic acid, and fumaric acid, and allyl methacrylate is preferably used.
  • the polyfunctional grafting agent is used to chemically bond the innermost hard layer polymer and the soft layer polymer, and the ratio used during the innermost hard layer polymerization is 0.01 to 0.3% by mass. .
  • the crosslinked soft layer polymer (b) constituting the acrylic granular composite is an alkyl acrylate having from 9 to 8 carbon atoms having an alkyl group of 1 to 8 in the presence of the innermost hard layer polymer (a). What is obtained by polymerizing a monomer mixture consisting of 10% by mass, 0.01 to 5% by mass of a multifunctional crosslinking agent and 0.5 to 5% by mass of a multifunctional grafting agent is preferred.
  • n-butyl acrylate or 2-ethylhexyl acrylate is preferably used as the alkyl acrylate having 4 to 8 carbon atoms in the alkyl group.
  • Examples of other monofunctional monomers that can be copolymerized include styrene and substituted styrene derivatives. As the ratio of the alkyl acrylate having 4 to 8 carbon atoms in the alkyl group and styrene increases, the glass transition temperature of the produced polymer (b) decreases as the former increases, that is, it can be softened.
  • the refractive index of the soft layer polymer (b) at room temperature is set to the innermost hard layer polymer (a), the outermost hard layer polymer (c), and the hard heat. It is more advantageous to make it closer to the plastic acrylic resin, and the ratio between them is selected in consideration of these.
  • polyfunctional grafting agent those mentioned in the section of the innermost layer hard polymer (a) can be used.
  • the polyfunctional grafting agent used here is used to chemically bond the soft layer polymer (b) and the outermost hard layer polymer (c), and the proportion used during the innermost hard layer polymerization is impact resistance. From the viewpoint of the effect of imparting properties, 0.5 to 5% by mass is preferable.
  • polyfunctional crosslinking agent generally known crosslinking agents such as divinyl compounds, diallyl compounds, diacrylic compounds, dimethacrylic compounds and the like can be used, but polyethylene glycol diacrylate (molecular weight 200 to 600) is preferably used.
  • the polyfunctional cross-linking agent used here is used to generate a cross-linked structure during the polymerization of the soft layer (b) and to exhibit the effect of imparting impact resistance.
  • the polyfunctional crosslinking agent is not an essential component because the crosslinked structure of the soft layer (b) is generated to some extent. Is preferably 0.01 to 5% by weight from the viewpoint of imparting impact resistance.
  • the outermost hard layer polymer (c) constituting the multi-layer structure acrylic granular composite has a methyl methacrylate of 80 to 99 mass in the presence of the innermost hard layer polymer (a) and the soft layer polymer (b). % And a monomer mixture comprising 1 to 20% by mass of an alkyl acrylate having 1 to 8 carbon atoms in the alkyl group is preferred.
  • the acrylic alkylate those described above are used, but methyl acrylate and ethyl acrylate are preferably used.
  • the proportion of the alkyl acrylate unit in the outermost hard layer (c) is preferably 1 to 20% by mass.
  • an alkyl mercaptan or the like can be used as a chain transfer agent to adjust the molecular weight for the purpose of improving the compatibility with the acrylic resin (A).
  • the outermost hard layer with a gradient such that the molecular weight gradually decreases from the inside toward the outside in order to improve the balance between elongation and impact resistance.
  • the monomer mixture for forming the outermost hard layer is divided into two or more, and the molecular weight is increased from the inside by a method of sequentially increasing the amount of chain transfer agent added each time. It is possible to make it smaller toward the outside.
  • the molecular weight formed at this time can also be examined by polymerizing the monomer mixture used each time under the same conditions, and measuring the molecular weight of the obtained polymer.
  • the particle diameter of the acrylic granular composite which is a multilayer structure polymer preferably used in the present invention is not particularly limited, but is preferably 10 nm or more and 1000 nm or less, and more preferably 20 nm or more and 500 nm or less. More preferably, it is most preferably 50 nm or more and 400 nm or less.
  • the mass ratio of the core and the shell is not particularly limited, but when the entire multilayer structure polymer is 100 parts by mass,
  • the core layer is preferably 50 parts by mass or more and 90 parts by mass or less, and more preferably 60 parts by mass or more and 80 parts by mass or less.
  • Examples of such commercially available multilayered acrylic granular composites include, for example, “Metablene” manufactured by Mitsubishi Rayon Co., “Kane Ace” manufactured by Kaneka Chemical Co., Ltd., “Paraloid” manufactured by Kureha Chemical Co., Ltd., Rohm and Haas “Acryloid” manufactured by KK, “Staffyroid” manufactured by Ganz Kasei Kogyo Co., Ltd., “Parapet SA” manufactured by Kuraray Co., Ltd., and the like can be used alone or in combination of two or more.
  • a graft copolymer obtained by copolymerizing a monomer mixture comprising a saturated carboxylic acid monomer, an aromatic vinyl monomer, and, if necessary, other vinyl monomers copolymerizable therewith. can be mentioned.
  • the rubbery polymer used for the acrylic particles that are the graft copolymer, but diene rubber, acrylic rubber, ethylene rubber, and the like can be used.
  • Specific examples include polybutadiene, styrene-butadiene copolymer, block copolymer of styrene-butadiene, acrylonitrile-butadiene copolymer, butyl acrylate-butadiene copolymer, polyisoprene, butadiene-methyl methacrylate copolymer.
  • the refractive indexes of the acrylic resin (A) and the acrylic particles are approximate because the transparency of the acrylic resin-containing film according to the present invention can be obtained.
  • the refractive index difference between the acrylic particles and the acrylic resin (A) is preferably 0.05 or less, more preferably 0.02 or less, and particularly preferably 0.01 or less.
  • a method of adjusting the monomer unit composition ratio of the acrylic resin (A) and / or the composition ratio of the rubbery polymer or monomer used in the acrylic particles The difference in refractive index can be reduced by the method of preparing the film, and an acrylic resin-containing film excellent in transparency can be obtained.
  • the difference in refractive index referred to here means that the acrylic resin-containing film according to the present invention is sufficiently dissolved in a solvent in which the acrylic resin (A) is soluble to obtain a cloudy solution, which is centrifuged.
  • the solvent was separated into a solvent-soluble part and an insoluble part by the operation, and the soluble part (acrylic resin (A)) and the insoluble part (acrylic particles) were purified, and then the measured refractive index (23 ° C., measurement wavelength: 550 nm). ) Difference.
  • the method of blending the acrylic particles with the acrylic resin (A) is not particularly limited, and after the acrylic resin (A) and other optional components are previously blended, the acrylic particles are usually added at 200 to 350 ° C.
  • a method of uniformly melting and kneading with a single or twin screw extruder while adding is preferably used.
  • a method in which a solution in which acrylic particles are dispersed in advance is added to and mixed with a solution (dope solution) in which acrylic resin (A) and cellulose ester resin (B) are dissolved, acrylic particles and other optional additives can be used.
  • acrylic particles can also be used as the acrylic particles according to the present invention.
  • Metabrene W-341 manufactured by Mitsubishi Rayon Co., Ltd.
  • Chemisnow MR-2G Chemisnow MR-2G
  • MS-300X manufactured by Soken Chemical Co., Ltd.
  • the acrylic resin-containing film of the present invention preferably contains 0.5 to 45% by mass of acrylic particles with respect to the total mass of the resin constituting the film.
  • a plasticizer may be contained in the film forming material.
  • the plasticizer that can be used is not particularly limited.
  • a polyhydric alcohol ester plasticizer a polyester plasticizer, a trivalent or higher aromatic polycarboxylic acid ester plasticizer, a glycolate plasticizer, Phosphate ester plasticizers, phthalate ester plasticizers, fatty acid ester plasticizers, sugar ester compounds, acrylic polymers, and the like can be used.
  • Particularly preferred are polyhydric alcohol plasticizers.
  • the addition amount of a phosphoric ester plasticizer shall be 6 mass% or less from a durable viewpoint of a polarization degree.
  • the plasticizer preferably has a 1% weight loss temperature (Td1) of 250 ° C. or higher, more preferably 280 ° C. or higher, and particularly preferably 300 ° C. or higher.
  • Td1 1% weight loss temperature
  • the polyhydric alcohol ester is composed of an ester of a dihydric or higher aliphatic polyhydric alcohol and a monocarboxylic acid, and preferably has an aromatic ring or a cycloalkyl ring in the molecule.
  • the polyhydric alcohol used in the polyhydric alcohol ester is represented by the following general formula (1).
  • R 1 represents an n-valent organic group
  • n represents a positive integer of 2 or more
  • the OH group represents an alcoholic hydroxyl group or a phenolic hydroxyl group.
  • preferable polyhydric alcohols include the following, but the present invention is not limited to these.
  • the monocarboxylic acid used in the polyhydric alcohol ester according to the present invention is not particularly limited, and known aliphatic monocarboxylic acid, alicyclic monocarboxylic acid, aromatic monocarboxylic acid and the like can be used. Use of an alicyclic monocarboxylic acid or aromatic monocarboxylic acid is preferable in terms of improving moisture permeability and retention. Examples of preferred monocarboxylic acids include the following, but the present invention is not limited thereto.
  • aliphatic monocarboxylic acid a fatty acid having a straight chain or a side chain having 1 to 32 carbon atoms can be preferably used. More preferably, it has 1 to 20 carbon atoms, and particularly preferably 1 to 10 carbon atoms.
  • acetic acid is preferred because the compatibility with the cellulose ester is increased, and it is also preferred to use a mixture of acetic acid and another monocarboxylic acid.
  • Preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecylic acid, lauric acid, tridecylic acid , Saturated fatty acids such as myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, heptacosanoic acid, montanic acid, melicic acid, laccelic acid, undecylenic acid, Examples thereof include unsaturated fatty acids such as oleic acid, sorbic acid, linoleic acid, linolenic acid and arachidonic acid.
  • Preferred alicyclic monocarboxylic acids are preferably cycloalkyl groups having 3 to 8 carbon atoms, and specific examples include cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, and cyclooctanecarboxylic acid.
  • aromatic monocarboxylic acids examples include those in which an alkyl group is introduced into the benzene ring of benzoic acid such as benzoic acid and toluic acid, and two or more benzene rings such as biphenyl carboxylic acid, naphthalene carboxylic acid, and tetralin carboxylic acid.
  • benzoic acid is preferred.
  • alicyclic monocarboxylic acids and aromatic monocarboxylic acids may be substituted, and preferred substituents include halogen atoms such as chlorine atom, bromine atom, fluorine atom, hydroxyl group, alkyl group, alkoxy group.
  • the molecular weight of the polyhydric alcohol ester is not particularly limited, but from the viewpoint of volatility, compatibility and the like, the molecular weight is preferably in the range of 300 to 1500, and more preferably in the range of 400 to 1000.
  • the monocarboxylic acid used in the polyhydric alcohol ester may be one kind or a mixture of two or more kinds. Moreover, all the OH groups in the polyhydric alcohol may be esterified, or a part of the OH groups may be left as they are.
  • the polyhydric alcohol ester can be synthesized by a known method. For example, a method of condensing and esterifying the monocarboxylic acid and the polyhydric alcohol in the presence of an acid, a method of previously reacting an organic acid with an acid chloride or acid anhydride and reacting with the polyhydric alcohol, There is a method of reacting a phenyl ester and a polyhydric alcohol, and it is preferable to select a method with a good yield appropriately depending on the target ester compound.
  • the polyhydric alcohol ester as a plasticizer may also serve as the polyhydric alcohol fatty acid ester.
  • polyester plasticizer it is preferable to use a polyester plasticizer having an aromatic ring or a cycloalkyl ring in the molecule.
  • a polyester plasticizer it does not specifically limit as a preferable polyester plasticizer, For example, it represents with the following general formula (i).
  • Formula (i): B- (GA) n1 -GB (Wherein B is a benzene monocarboxylic acid residue, G is an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or an oxyalkylene glycol residue having 4 to 12 carbon atoms, A represents an alkylene dicarboxylic acid residue having 2 to 12 carbon atoms or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n1 represents an integer of 1 or more.)
  • benzene monocarboxylic acid component of the polyester plasticizer used in the present invention examples include benzoic acid, para-tert-butylbenzoic acid, orthotoluic acid, metatoluic acid, p-toluic acid, dimethylbenzoic acid, ethylbenzoic acid, and normalpropyl.
  • benzoic acid, aminobenzoic acid, acetoxybenzoic acid and the like can be used as one kind or a mixture of two or more kinds, respectively.
  • alkylene glycol component having 2 to 12 carbon atoms of the polyester plasticizer examples include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 2- Methyl 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2,2-diethyl-1,3- Propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3propanediol (3,3-dimethylolheptane), 3-methyl-1,5-pentanediol 1,6 -Hexanediol, 2,2,4-trimethyl 1,3-pentanediol, 2-ethyl 1,3-hexaned
  • Examples of the oxyalkylene glycol component having 4 to 12 carbon atoms of the aromatic terminal ester include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, and the like. Or it can be used as a mixture of two or more.
  • alkylene dicarboxylic acid component having 4 to 12 carbon atoms of the aromatic terminal ester examples include succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, and dodecanedicarboxylic acid. These are used as one kind or a mixture of two or more kinds.
  • arylene dicarboxylic acid component having 6 to 12 carbon atoms include phthalic acid, isophthalic acid, terephthalic acid, 1,5-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, and the like.
  • the polyester plasticizer used in the present invention preferably has a number average molecular weight of 400 to 2000, more preferably 500 to 1500.
  • the acid value is preferably 0.5 mgKOH / g or less, and the hydroxyl value is preferably 25 mgKOH / g or less, more preferably the acid value is 0.3 mgKOH / g or less, and the hydroxyl value is 15 mgKOH / g or less. Is preferred.
  • the trivalent or higher aromatic polyvalent carboxylic acid ester plasticizer is preferably trimesic acid ester, trimellitic acid ester or pyromellitic acid ester.
  • the alcohol that forms an ester with an aromatic polycarboxylic acid is preferably an alcohol having 1 to 8 carbon atoms.
  • Examples of particularly preferred trivalent or higher aromatic polycarboxylic acid ester plasticizers include tributyl trimesate, trihexyl trimesate, tri-2-ethyl-hexyl trimesate, tricyclohexyl trimesate, tributyl trimellitic acid, trimellitate Trihexyl acid, tri-2-ethyl-hexyl trimellitic acid, tricyclohexyl trimellitic acid, tetrabutyl pyromellitic acid, tetrahexyl pyromellitic acid, tetra-2-ethylhexyl pyromellitic acid, tetracyclohexyl pyromellitic acid, etc.
  • the invention is not limited to these examples.
  • glycolate plasticizers ethyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, and phosphate ester plasticizers are triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl.
  • phthalate plasticizers such as phosphate, trioctyl phosphate, tributyl phosphate, 1,3-phenylene bis (dixylenyl phosphate), 1,3-phenylene bis (diphenyl phosphate), diethyl phthalate, dimethoxyethyl phthalate, dimethyl Phthalate, dioctyl phthalate, dibutyl phthalate, butyl benzyl phthalate, di-2-ethylhexyl phthalate and the like can be used.
  • citrate plasticizers such as acetyltributyl citrate, epoxidized oil plasticizers, and the like can also be used.
  • Antioxidant, Heat degradation inhibitor As an antioxidant and a thermal degradation inhibitor, generally known degradation inhibitors (antioxidants, peroxide decomposition agents, radical inhibitors, metal deactivators, acid scavengers, amines, etc.) ) Can be used. In particular, lactone, sulfur, phenol, double bond, hindered amine, and phosphorus compounds can be preferably used.
  • the deterioration preventing agents are described in JP-A-3-199201, JP-A-5-194789, JP-A-5-271471, and JP-A-6-107854.
  • phenolic compound those having a 2,6-dialkylphenol structure are preferable, for example, those commercially available from Ciba Japan Co., Ltd. under the trade names Irganox 1076 and Irganox 1010.
  • the phosphorous compounds are, for example, Sumitomo Chemical Co., Ltd., Sumilizer-GP, ADEKA Co., Ltd., ADK STAB PEP-24G, ADK STAB PEP-36 and ADK STAB 3010, Ciba Japan Co., Ltd., IRGAFOS P- EPQ, commercially available from Sakai Chemical Co., Ltd. under the trade name GSY-P101 is preferred.
  • the hindered amine compound is preferably commercially available from Ciba Japan Co., Ltd. under the trade name of Tinuvin 144 and Tinuvin 770, and from ADEKA Co., Ltd. under the name of ADK STAB LA-52.
  • the above-mentioned sulfur compounds are preferably those commercially available from Sumitomo Chemical Co., Ltd. under the trade names Sumilizer TPL-R and Sumilizer TP-D.
  • the above-mentioned double bond compounds are preferably those commercially available from Sumitomo Chemical Co., Ltd. under the trade names Sumilizer-GM and Sumilizer-GS.
  • the amount of these antioxidants and the like to be added is appropriately determined in accordance with the process at the time of recycling. Generally, the range of 0.05 to 5% by mass with respect to the resin as the main raw material of the film. Is added.
  • antioxidants and thermal degradation inhibitors can obtain a synergistic effect by using several different types of compounds in combination rather than using only one kind.
  • the combined use of lactone, phosphorus, phenol and double bond compounds is preferred.
  • a colorant may be used.
  • the colorant means a dye or a pigment, but in the present invention, it means an agent having the effect of making the color tone of the liquid crystal screen blue, adjusting the yellow index (yellowness), and reducing haze.
  • dyes and pigments can be used as the colorant, but anthraquinone dyes, azo dyes, phthalocyanine pigments and the like are effective.
  • the ultraviolet absorber used in the present invention is not particularly limited, for example, oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, triazine compounds, nickel complex compounds, inorganic powders Examples include the body. It is good also as a polymer type ultraviolet absorber.
  • the UV absorber preferably used in the present invention is preferably a benzotriazole-based UV absorber or a benzophenone-based UV absorber that has high transparency and is excellent in the effect of preventing the deterioration of the polarizing plate and the liquid crystal element, and has less unnecessary coloring. Benzotriazole ultraviolet absorbers are particularly preferred.
  • the ultraviolet absorber used in the present invention for example, TINUVIN109, TINUVIN171, TINUVIN326, TINUVIN327, TINUVIN328, TINUVIN900, TINUVIN928 manufactured by Ciba Japan Co., Ltd., LA-31 manufactured by ADEKA Corporation, etc. are preferably used.
  • the present invention is not limited to these.
  • a polymer UV absorber can also be preferably used, and in particular, a polymer type UV absorber described in JP-A-6-148430 is preferably used.
  • An ultraviolet absorber may be used independently and 2 or more types of mixtures may be sufficient as it.
  • the amount of the UV absorber used is not uniform depending on the type of compound and the use conditions, but when the dry film thickness of the cellulose ester film is 30 to 200 ⁇ m, 0.5 to 4.0 mass with respect to the cellulose ester film. % Is preferable, and 0.6 to 3.5% by mass is more preferable.
  • the film of the present invention can be produced by a solution casting method or a melt casting method. First, the melt film forming method will be described below.
  • melt casting method Film forming methods by the melt film forming method can be classified into melt extrusion forming methods, press forming methods, inflation methods, injection forming methods, blow forming methods, stretch forming methods, and the like. Among these, in order to obtain a film having excellent mechanical strength and surface accuracy, the melt extrusion molding method is excellent.
  • the film production method of the present invention will be described by taking the melt extrusion molding method as an example.
  • the conditions for melt extrusion can be performed in the same manner as the conditions used for general thermoplastic resins.
  • Pellet manufacturing process A plurality of raw materials used for melt extrusion are preferably kneaded and pelletized in advance.
  • Pelletization may be a known method, for example, dry acrylic resin, cellulose ester resin and additives are fed to an extruder with a feeder and kneaded using a uniaxial or biaxial extruder, extruded from a die into a strand, It can be done by water cooling or air cooling and cutting.
  • high concentration master pellets may be prepared and mixed with main pellets in an extruder during film formation.
  • the cellulose ester resin easily absorbs moisture, it is preferable to dry it at 70 to 140 ° C. for 3 hours or more with a dehumidifying hot air dryer or a vacuum dryer so that the moisture content is 200 ppm or less, and further 100 ppm or less.
  • Additives may be mixed before being supplied to the extruder, or may be supplied by individual feeders. A small amount of an additive such as an antioxidant is preferably mixed in advance in order to mix uniformly.
  • a vacuum nauter mixer is preferable because it can dry and mix simultaneously.
  • a portion that comes into contact with air such as an outlet from a feeder part or a die is in an atmosphere of dehumidified air or dehumidified nitrogen gas.
  • the extruder is preferably processed at a low temperature so as to suppress shearing force and prevent the resin from deteriorating (molecular weight reduction, coloring, gel formation, etc.).
  • a twin screw extruder a deep groove type screw is used. Are preferably rotated in the same direction. From the uniformity of kneading, the meshing type is preferable. Kneader discs can improve kneadability, but care must be taken against shearing heat generation.
  • ⁇ Suction from the vent hole may be performed as necessary. Since there is almost no volatile component at low temperatures, there may be no vent hole.
  • the b * value which is an index of yellowness, is preferably in the range of -5 to 10, more preferably in the range of -1 to 8, and preferably in the range of -1 to 5. More preferred.
  • the b * value can be measured at a viewing angle of 10 ° using a spectrocolorimeter CM-3700d (manufactured by Konica Minolta Sensing Co., Ltd.) and a light source of D65 (color temperature 6504K).
  • ⁇ Melten extrusion process It is preferable to dry materials such as pellets in advance. It is desirable to dry the moisture to 200 ppm or less, preferably 100 ppm or less using a vacuum or reduced pressure drier or a dehumidifying hot air drier.
  • the polymer dried under dehumidified hot air, vacuum or reduced pressure is melted using a single or twin screw type extruder and filtered with a leaf disk type filter etc. to remove foreign matter, and then flowed in a film form from a casting die. And solidify on a cooling roll.
  • extruder a commercially available extruder can be used, but a melt-kneading extruder is preferable, and a single-screw extruder or a twin-screw extruder may be used.
  • the temperature at which the film constituent material in the extruder is melted varies depending on the viscosity and discharge amount of the film constituent material, the thickness of the sheet to be produced, etc., but is preferably 150 to 300 ° C., more preferably 180 to 270 ° C., 200 More preferred is ⁇ 260 ° C. If the temperature is too low, poor dissolution and an increase in melt viscosity occur, and if the temperature is too high, thermal degradation of the material occurs.
  • the melt viscosity at the time of extrusion is 1 to 10000 Pa ⁇ s, preferably 10 to 1000 Pa ⁇ s. If the melt viscosity is too high, the residence time in the extruder becomes longer due to an increase in pressure.
  • the residence time of the film constituent material in the extruder is preferably shorter, and is within 5 minutes, preferably within 3 minutes, more preferably within 2 minutes.
  • the residence time depends on the type of extruder and the extrusion conditions, but it can be shortened by adjusting the material supply amount, L / D, screw rotation speed, screw groove depth, etc. is there.
  • the shape of the screw and the number of revolutions of the extruder are appropriately selected depending on the viscosity of the film constituting material, the discharge amount, and the like.
  • the shear rate in the extruder is from 1 / second to 10,000 / second, preferably from 5 / second to 1000 / second, and more preferably from 10 / second to 100 / second.
  • the molten resin extruded from the extruder is sent to a casting die and extruded into a film from the slit of the casting die.
  • the casting die is not particularly limited as long as it is used for producing a sheet or a film.
  • hard chromium, chromium carbide, chromium nitride, titanium carbide, titanium carbonitride, titanium nitride, super steel, ceramic (tungsten carbide, aluminum oxide, chromium oxide), etc. are sprayed or plated and surface processed Buffing, lapping using a # 1000 or higher whetstone, surface cutting using a diamond whetstone of # 1000 or higher (the cutting direction is perpendicular to the resin flow direction), electrolytic polishing, electrolytic composite polishing, etc. And the like.
  • the preferred material of the lip portion of the casting die is the same as that of the casting die.
  • the surface accuracy of the lip is preferably 0.5S or less, and more preferably 0.2S or less.
  • the slit of this casting die is configured so that the gap can be adjusted.
  • one is a flexible lip having low rigidity and easily deformed, and the other is preferably a fixed lip from the viewpoint of easy gap adjustment.
  • a large number of heat bolts are arranged at a constant pitch in the width direction of the casting die for gap adjustment.
  • Each heat bolt is provided with a block having an embedded electric heater and a cooling medium passage, and each heat bolt vertically penetrates each block.
  • the base of the heat bolt is fixed to the die body, and the tip is in contact with the outer surface of the flexible lip. Then, while constantly cooling the block, the input of the embedded electric heater is increased or decreased to increase or decrease the temperature of the block, thereby causing the heat bolt to thermally expand and contract to displace the flexible lip and adjust the thickness of the acrylic film.
  • Thickness gauges are installed at the required locations in the wake of the die, and the web thickness information detected thereby is fed back to the control device.
  • the thickness information is compared with the set thickness information by the control device, and correction control comes from the same device. It is also possible to control the power or the ON rate of the heat bolt heating element by the amount signal.
  • the heat bolt preferably has a length of 20 to 40 cm and a diameter of 7 to 14 mm, and a plurality of (for example, several tens) heat bolts are preferably arranged at a pitch of 20 to 40 mm.
  • a gap adjusting member mainly composed of a bolt for adjusting the slit gap by manually moving back and forth in the axial direction may be provided.
  • the slit gap adjusted by the gap adjusting member is usually 200 to 2000 ⁇ m, preferably 300 to 1000 ⁇ m, more preferably 400 to 800 ⁇ m.
  • the extrusion flow rate is preferably carried out stably by introducing a gear pump. Further, a stainless fiber sintered filter is preferably used as a filter used for removing foreign substances.
  • a stainless steel fiber sintered filter is a united stainless steel fiber body that is intricately entangled and then compressed and sintered at the contact location. The density is changed according to the thickness of the fiber and the amount of compression, and the filtration accuracy is improved. Can be adjusted.
  • the filter is a multilayer body combining filter media having different filtration accuracy. Further, it is preferable to adopt a configuration in which the filtration accuracy is sequentially increased or a method in which coarse and dense filtration accuracy is repeated, so that the filtration life of the filter is extended and the accuracy of supplementing foreign matters and gels can be improved.
  • a defect is called a die line, but in order to reduce surface defects such as the die line, use one that has as little scratches as possible in the inside of the die and lip, and piping from the extruder to the die. It is preferable to have a structure in which the resin retention portion is minimized.
  • the inner surface that comes into contact with the molten resin is subjected to surface treatment that makes it difficult for the molten resin to adhere to the surface by reducing the surface roughness or using a material with low surface energy.
  • a hard chrome plated or ceramic sprayed material is polished so that the surface roughness is 0.2 S or less.
  • Additives such as plasticizers may be mixed with the resin in advance, or may be kneaded in the middle of the extruder. In order to add uniformly, it is preferable to use a mixing apparatus such as a static mixer.
  • ⁇ Cooling roll ⁇ There is no particular limitation on the cooling roll, but it is a roll having a structure in which a heat medium or a coolant body in which the temperature can be controlled flows through a highly rigid metal roll, and the size of the roll is used to cool the melt-extruded film.
  • the diameter of the cooling roll is usually about 100 mm to 1 m.
  • the surface material of the cooling roll includes carbon steel, stainless steel, aluminum, titanium and the like. Further, in order to increase the surface hardness or improve the releasability from the resin, it is preferable to perform a surface treatment such as hard chrome plating, nickel plating, amorphous chrome plating, or ceramic spraying.
  • the cooling roll is made of seamless steel pipe with a wall thickness of about 20-30mm, and the surface is mirror finished.
  • the surface roughness of the cooling roll surface is preferably 0.1 ⁇ m or less in terms of Ra, and more preferably 0.05 ⁇ m or less.
  • the smoother the roll surface the smoother the surface of the resulting film.
  • the cooling roll is at least one and preferably has two or more.
  • the surface temperature Tr of the cooling roll is set to Tg ⁇ 50 ⁇ Tr ⁇ Tg.
  • the surface temperature Tr1 of the first cooling roll and the surface temperature Tr2 of the second cooling roll are set to Tg-50 ⁇ Tr1 ⁇ Tg and Tg-50 ⁇ Tr2 ⁇ Tg.
  • Tr2 > Tr1, and 0 ⁇ Tr2-Tr1 ⁇ 50.
  • re-dissolution can be promoted also by the contact time between the cellulose ester film and the first and second cooling rolls, in the present invention, 1.0 second or more and 3.0 seconds or less are preferable.
  • the contact time was expressed by the number of seconds calculated from the circumferential distance between the contact point at which the film and the roller began to contact and the contact point at which the film began to peel off, and the film conveyance speed.
  • the peripheral speed R2 of the second cooling roll is preferably larger than the peripheral speed R1 of the first cooling roll. That is, tension acts on the film between the two rolls, and the adhesion between the film and the first roll is increased.
  • the ratio of the peripheral speeds is preferably in the range of 1.00 to 1.05, and if it exceeds 1.05, there is a risk that the film breaks.
  • the third and subsequent roll peripheral speeds are greater than the peripheral speed of the cooling roll immediately before.
  • the touch roll that abuts on the cooling roll has an elastic surface, and can be deformed along the surface of the cooling roll by a pressing force to the cooling roll to form a nip with the cooling roll. It is preferable that
  • Examples of the elastic touch roll according to the present invention include Japanese Patent No. 3194904, Japanese Patent No. 3422798, Japanese Patent Application Laid-Open No. 03-124425, Japanese Patent Application Laid-Open No. 08-224772, Japanese Patent Application Laid-Open No. 07-1000096, Japanese Patent Application Laid-Open No. 10-272676, and WO 97. / 028950, JP-A-11-235747, JP-A-2002-36332, JP-A-2002-36333, JP-A-2005-172940 and JP-A-2005-280217 Can be used.
  • the elastic touch roll used in the present invention has a double structure of a metal outer cylinder and an inner cylinder, and has a space so that a cooling fluid can flow between them.
  • the metal outer cylinder has elasticity, it can control the temperature of the surface of the touch roll with high accuracy, and by utilizing the property of being elastically deformed appropriately, the distance for pressing the film in the longitudinal direction can be increased. With this effect, the effect of the present invention can be obtained that there are no bright and dark stripes and uneven spots when an image is displayed on a liquid crystal display device.
  • the thickness of the metal outer cylinder is 0.003 ⁇ (thickness of the metal outer cylinder) / (touch roll radius) ⁇ 0.03, it is preferable because the elasticity is appropriate. If the radius of the touch roll is large, even if the thickness of the metal outer cylinder is thick, the touch roll can be appropriately bent. If the thickness of the metal outer cylinder is too thin, the strength is insufficient and there is a concern of breakage. On the other hand, if it is too thick, the roll mass becomes too heavy and there is a concern about uneven rotation. Therefore, the thickness of the metal outer cylinder is preferably 0.1 to 5 mm.
  • the surface roughness of the metal outer cylinder surface is preferably 0.1 ⁇ m or less, more preferably 0.05 ⁇ m or less, in terms of arithmetic average roughness Ra.
  • the material of the metal outer cylinder is required to be smooth and have moderate elasticity and durability. For this reason, carbon steel, stainless steel, titanium, nickel produced by electroforming, etc. can be preferably used. Further, in order to increase the hardness of the surface or improve the releasability from the resin, it is preferable to perform a surface treatment such as hard chrome plating, nickel plating, amorphous chrome plating, or ceramic spraying. It is preferable that the surface processed is further polished to have the surface roughness described above.
  • the inner cylinder is preferably a lightweight and rigid metallic inner cylinder such as carbon steel, stainless steel, aluminum, titanium or the like. By giving rigidity to the inner cylinder, it is possible to suppress the rotational shake of the roll. A sufficient rigidity can be obtained by setting the thickness of the inner cylinder to 2 to 10 times that of the outer cylinder.
  • the inner cylinder may be further covered with a resin elastic material such as silicone or fluororubber.
  • the structure of the space through which the cooling fluid flows can be any structure as long as the temperature of the roll surface can be controlled uniformly.
  • the flow and the return flow alternately in the width direction or spirally. Temperature control with a small temperature distribution on the roll surface is possible.
  • the cooling fluid is not particularly limited, and water or oil can be used according to the temperature range to be used.
  • the surface temperature (Tr0) of the elastic touch roll is preferably lower than the glass transition temperature (Tg) of the film. If it is higher than Tg, the peelability between the film and the roll may be inferior. More preferably, it is Tg-50 ° C. to Tg.
  • the elastic touch roll used in the present invention preferably has a crown roll shape in which the central portion in the width direction has a larger diameter than the end portion.
  • the touch roll is generally pressed against the film by pressing means at both ends, but in this case, since the touch roll is bent, there is a phenomenon that the touch roll is strongly pressed toward the end. Highly uniform pressing is possible by making the roll into a crown shape.
  • the width of the elastic touch roll used in the present invention is preferably larger than the film width because the entire film can be closely attached to the cooling roll.
  • both end portions of the film become ear height (end portion) due to a neck-in phenomenon.
  • the width of the metal outer cylinder may be made narrower than the film width so as to escape from the high ear portion.
  • the outer diameter of the metal outer cylinder may be reduced to escape the ear height.
  • a support roll may be arranged on the opposite side of the touch roll with respect to the cooling roll.
  • ⁇ A device for cleaning dirt on the elastic touch roll may be provided.
  • the cleaning device for example, a method of pressing the roll surface with a member such as a nonwoven fabric infiltrated with a solvent if necessary, a method of bringing the roll into contact with a liquid, a plasma discharge such as corona discharge or glow discharge, A method for volatilizing dirt can be preferably used.
  • the temperature control roll may be brought into contact with the touch roll, temperature-controlled air may be sprayed, or a heat medium such as a liquid may be brought into contact.
  • the touch roll linear pressure when pressing the elastic touch roll is 9.8 N / cm or more and 147 N / cm or less. If the linear pressure is smaller than this range, the die line cannot be sufficiently eliminated.
  • the linear pressure is a value obtained by dividing the force with which the elastic touch roll presses the film by the film width at the time of pressing.
  • the method for setting the linear pressure within the above range is not particularly limited, and for example, both ends of the roll can be pressed with an air cylinder or a hydraulic cylinder.
  • the film may be pressed indirectly by pressing the elastic touch roll with the support roll.
  • the touch roll side film surface temperature Tt immediately before the extruded film is clamped by the touch roll is preferably Tg ⁇ Tt ⁇ Tg + 110 ° C.
  • the viscosity of the film when sandwiching the film can be set to an appropriate range, and the die line can be corrected.
  • the film surface and the roll are bonded uniformly, and the die line can be corrected.
  • the method of setting the film temperature at the time of pressing in the above range is not particularly limited.
  • the distance between the die and the cooling roll is made closer, and the cooling between the die and the cooling roll is suppressed, or between the die and the cooling roll.
  • Examples of the method include heat insulation by surrounding with a heat insulating material, or heating by hot air, an infrared heater, microwave heating, or the like.
  • Film surface temperature and roll surface temperature can be measured with a non-contact infrared thermometer. Specifically, using a non-contact handy thermometer (IT2-80, manufactured by Keyence Co., Ltd.), 10 points in the width direction of the film are measured at a distance of 0.5 m from the object to be measured.
  • IT2-80 manufactured by Keyence Co., Ltd.
  • Elastic touch roll side film surface temperature Tt refers to the film surface temperature measured with a non-contact infrared thermometer from the touch roll side with the touch roll removed from the film being transported.
  • the die line correction effect is more greatly manifested by reducing the pressure from the opening (lip) of the casting die to the cooling roll to 70 kPa or less.
  • the reduced pressure is 50 to 70 kPa.
  • the method for maintaining the pressure of the portion from the opening (lip) of the casting die to the cooling roll to 70 kPa or less, but there is a method of reducing the pressure by covering the periphery of the casting die with a pressure-resistant member. .
  • the suction device is preferably subjected to a treatment such as heating with a heater so that the device itself does not become a place where the sublimate adheres.
  • a treatment such as heating with a heater
  • a melt containing cellulose ester is extruded from a die into a film, and a film obtained with a draw ratio of 5 or more and 30 or less is conveyed while being pressed against a cooling roll by an elastic touch roll.
  • the draw ratio is a value obtained by dividing the lip clearance of the die by the average film thickness of the film solidified on the cooling roll.
  • the draw ratio can be adjusted by the die lip clearance and the cooling roll take-up speed.
  • the die lip clearance is preferably 900 ⁇ m or more, more preferably 1 mm or more and 2 mm or less. Even if it is too large or too small, spotted unevenness may not be improved.
  • a well-known roll can be used for the roll which has the elastic body surface used for such a purpose.
  • a device for cleaning the drum and roll It is preferable to add a device for cleaning the drum and roll to the manufacturing apparatus according to the present invention.
  • the cleaning device There are no particular restrictions on the cleaning device. For example, there are a method of niping a brush roll, a water absorbing roll, an adhesive roll, a wiping roll, an air blow method of blowing clean air, a laser incinerator, or a combination thereof. is there.
  • the film obtained as described above passes through the step of coming into contact with the cooling roll, and then 1.1 (10%) to 2.1 in at least one direction of the length (film transport direction) and the width (width direction). Stretch 5 (150%) times.
  • a stretching treatment is performed to adjust retardation.
  • the saponification suitability can be further strengthened by stretching.
  • the stretched portion exposes the high active energy portion of the film from the surface, and the portion improves the saponification suitability.
  • the stretching temperature is usually in the temperature range of Tg to Tg + 50 ° C., preferably Tg to Tg + 40 ° C. of the resin constituting the film.
  • the stretching is preferably performed under a uniform temperature distribution controlled in the width direction.
  • the temperature is preferably within ⁇ 2 ° C, more preferably within ⁇ 1 ° C, and particularly preferably within ⁇ 0.5 ° C.
  • known heat setting conditions, cooling, and relaxation treatment may be performed, and adjustment can be made as appropriate so as to have characteristics required for the target film.
  • the latter method can be performed by using a general simultaneous biaxial stretching machine, and by gradually and gradually narrowing the interval between adjacent clips in the longitudinal direction by driving the clip portion by, for example, a pantograph method or a linear drive method. it can.
  • the dimensional change rate of the film can be reduced by shrinking 0.5% to 10% in both the longitudinal direction and the width direction.
  • the stretching is effective as a means for compensating for the low elastic modulus of the melt-formed film.
  • Stretching can be performed sequentially or simultaneously, for example, in the longitudinal direction of the film and in the direction orthogonal to the longitudinal direction of the film, that is, in the width direction.
  • the film thickness variation of the film obtained can be reduced by stretching in the biaxial directions perpendicular to each other. If the film thickness variation is too large, the retardation will be uneven, and unevenness such as coloring may be a problem when used in a liquid crystal display.
  • the film thickness variation of the film is preferably ⁇ 3%, and more preferably ⁇ 1%.
  • the film After stretching, after slitting the edge of the film to a product width with a slitter, the film is subjected to knurling (embossing) on both ends of the film by a knurling device consisting of an embossing ring and a back roll, and a winder By taking up with, the sticking in a film (original winding) and generation
  • the knurling method can process a metal ring having an uneven pattern on its side surface by heating or pressing.
  • the film is turned into a take-up roll while keeping the shortest distance between the outer peripheral face of the cylindrical roll film and the outer peripheral face of the movable transport roll immediately before this. It is to be wound up.
  • a means such as a static elimination blower for removing or reducing the surface potential of the film is provided in front of the winding roll.
  • the winder related to the production of the film of the present invention may be generally used, and it is wound by a winding method such as a constant tension method, a constant torque method, a taper tension method, or a program tension control method with a constant internal stress. Can be taken.
  • the initial winding tension when winding the acrylic film is preferably 90.2 to 300.8 N / m.
  • the film is preferably wound under environmental conditions of a temperature of 20 to 30 ° C. and a humidity of 20 to 60% RH. If the temperature in the winding process is in the range of 20 to 30 ° C., there will be no wrinkles and the acrylic film winding quality will not deteriorate. Further, if the humidity in the film winding process is 20 to 60% RH, the film winding quality deterioration due to moisture absorption is reduced, the winding quality is excellent, there is no sticking failure, and there is no deterioration in transportability.
  • the winding core for winding the film into a roll may be any material as long as it is a cylindrical core, but is preferably a hollow plastic core.
  • the plastic material may be any heat-resistant plastic that can withstand the heat treatment temperature, and examples thereof include phenol resins, xylene resins, melamine resins, polyester resins, and epoxy resins.
  • thermosetting resin reinforced with a filler such as glass fiber is preferable.
  • a hollow plastic core a wound core made of FRP having an outer diameter of 6 inches (hereinafter, 1 inch is 2.54 cm) and an inner diameter of 5 inches is used.
  • the roll length is preferably 10 to 7500 m, more preferably 50 to 5500 m in consideration of productivity and transportability.
  • the width of the polarizer protective film at this time can be selected from the width of the polarizer and the width suitable for the production line, but it is 0.5 to 4.0 m, preferably 1.0 to 3.0 m. It is preferable to manufacture a film and to wind up in roll shape.
  • Haze value is used as an index for judging the transparency of the film in the present invention.
  • liquid crystal display devices used outdoors are required to have sufficient brightness and high contrast even in a bright place. Therefore, the haze value is required to be 0.5% or less, and 0.35% or less. More preferably.
  • the film of the present invention preferably has a total light transmittance of 90% or more, more preferably 92% or more. In order to achieve excellent transparency expressed by such total light transmittance, it is necessary not to introduce additives and copolymerization components that absorb visible light, or to remove foreign substances in the polymer by high-precision filtration. It is effective to reduce the diffusion and absorption of light inside the film.
  • the film thickness of the polarizer protective film of the present invention is not particularly limited, but when used for the polarizer protective film described later, it is preferably 20 to 200 ⁇ m, more preferably 25 to 100 ⁇ m, and 30 to 65 ⁇ m. It is particularly preferred that
  • the amount of the solvent contained is 0.01% by mass or less when wound as a roll film.
  • the amount of the solvent can be measured by the following method.
  • Organic solvent useful for forming a dope when the film of the present invention is produced by the solution casting method is an acrylic resin (A), a cellulose ester resin (B), and optionally acrylic particles and other additives at the same time. Any material that can be dissolved can be used without limitation.
  • methylene chloride as a non-chlorinated organic solvent, methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro- 2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, nitroethane, etc.
  • Methylene chloride, methyl acetate, ethyl acetate and acetone can be preferably used.
  • the dope preferably contains 1 to 40% by mass of a linear or branched aliphatic alcohol having 1 to 4 carbon atoms.
  • a linear or branched aliphatic alcohol having 1 to 4 carbon atoms.
  • the ratio of alcohol in the dope increases, the web gels and peeling from the metal support becomes easy.
  • acrylic resin (A) and cellulose ester in non-chlorine organic solvent system There is also a role of promoting dissolution of the resin (B).
  • a solvent containing methylene chloride and a linear or branched aliphatic alcohol having 1 to 4 carbon atoms includes an acrylic resin (A), a cellulose ester resin (B), and, in some cases, three kinds of acrylic particles. Is preferably a dope composition in which at least 15 to 45% by mass is dissolved.
  • linear or branched aliphatic alcohol having 1 to 4 carbon atoms examples include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, and tert-butanol. Ethanol is preferred because of the stability of these dopes, the relatively low boiling point, and good drying properties.
  • Dissolution step In an organic solvent mainly composed of a good solvent for the acrylic resin (A) and the cellulose ester resin (B), the acrylic resin (A), the cellulose ester resin (B), and optionally acrylic particles in a dissolution vessel, The step of dissolving other additives while stirring to form a dope, or the acrylic resin (A) and cellulose ester resin (B) solutions are mixed with acrylic particle solutions and other additive solutions as the main solution. This is a step of forming a dope that is a liquid.
  • a method carried out at normal pressure a method carried out below the boiling point of the main solvent, a method carried out under pressure above the boiling point of the main solvent, JP-A-9-95544
  • Various dissolution methods such as a method of performing a cooling dissolution method as described in JP-A-9-95557 or JP-A-9-95538, a method of performing at a high pressure as described in JP-A-11-21379, and the like.
  • a method in which pressure is applied at a temperature equal to or higher than the boiling point of the main solvent is particularly preferable.
  • the acrylic resin (A) and cellulose ester resin (B) in the dope are preferably in the range of 15 to 45% by mass in total.
  • a filter medium having a collected particle diameter of 0.5 to 5 ⁇ m and a drainage time of 10 to 25 sec / 100 ml.
  • the aggregate remaining at the time of particle dispersion and the aggregate generated when the main dope is added are aggregated by using a filter medium having a collected particle diameter of 0.5 to 5 ⁇ m and a drainage time of 10 to 25 sec / 100 ml. Can only be removed.
  • the concentration of particles is sufficiently thinner than that of the additive solution, so that the aggregates do not stick together during filtration and the filtration pressure does not increase suddenly.
  • the main dope may contain about 10 to 50% by weight of recycled material.
  • the return material may contain acrylic particles. In that case, it is preferable to control the addition amount of the acrylic particle addition liquid in accordance with the addition amount of the return material.
  • the additive liquid containing acrylic particles preferably contains 0.5 to 10% by mass of acrylic particles, more preferably 1 to 10% by mass, and more preferably 1 to 5% by mass. Most preferably.
  • the additive solution is preferable because it has a low viscosity and is easy to handle and can be easily added to the main dope.
  • the return material is a product obtained by finely pulverizing a film, and is produced by forming a film by cutting off both sides of the film, or by using an original film that has been speculated out of scratches.
  • acrylic resin cellulose ester resin, and in some cases, acrylic particles kneaded into pellets can be preferably used.
  • An endless metal belt such as a stainless steel belt or a rotating metal drum, which supports the dope is fed to a pressure die through a liquid feed pump (for example, a pressurized metering gear pump) and supported infinitely. This is a step of casting a dope from a pressure die slit to a casting position on the body.
  • a liquid feed pump for example, a pressurized metering gear pump
  • ⁇ Pressure dies that can adjust the slit shape of the die base and make the film thickness uniform are preferred.
  • the pressure die include a coat hanger die and a T die, and any of them is preferably used.
  • the surface of the metal support is a mirror surface.
  • two or more pressure dies may be provided on the metal support, and the dope amount may be divided and stacked. Or it is also preferable to obtain the film of a laminated structure by the co-casting method which casts several dope simultaneously.
  • Solvent evaporation step In this step, the web (the dope is cast on the casting support and the formed dope film is called a web) is heated on the casting support to evaporate the solvent.
  • the web on the support after casting is preferably dried on the support in an atmosphere of 40 to 100 ° C. In order to maintain the atmosphere at 40 to 100 ° C., it is preferable to apply hot air at this temperature to the upper surface of the web or heat by means such as infrared rays.
  • Peeling process It is the process of peeling the web which the solvent evaporated on the metal support body in a peeling position. The peeled web is sent to the next process.
  • the temperature at the peeling position on the metal support is preferably 10 to 40 ° C, more preferably 11 to 30 ° C.
  • the amount of residual solvent at the time of peeling of the web on the metal support at the time of peeling is preferably 50 to 120% by mass depending on the strength of drying conditions, the length of the metal support, and the like. If the web is peeled off at a time when the amount of residual solvent is larger, if the web is too soft, the flatness at the time of peeling will be lost, and slippage and vertical stripes are likely to occur due to the peeling tension. The amount of solvent is determined.
  • the amount of residual solvent in the web is defined by the following formula.
  • Residual solvent amount (%) (mass before web heat treatment ⁇ mass after web heat treatment) / (mass after web heat treatment) ⁇ 100 Note that the heat treatment for measuring the residual solvent amount represents performing heat treatment at 115 ° C. for 1 hour.
  • the peeling tension at the time of peeling the metal support and the film is usually 196 to 245 N / m. However, if wrinkles easily occur at the time of peeling, it is preferable to peel with a tension of 190 N / m or less. It is preferable to peel at a minimum tension of ⁇ 166.6 N / m, and then peel at a minimum tension of ⁇ 137.2 N / m, and particularly preferable to peel at a minimum tension of ⁇ 100 N / m.
  • the temperature at the peeling position on the metal support is preferably ⁇ 50 to 40 ° C., more preferably 10 to 40 ° C., and most preferably 15 to 30 ° C.
  • the drying means is generally to blow hot air on both sides of the web, but there is also a means to heat by applying microwaves instead of wind. Too rapid drying tends to impair the flatness of the finished film. Drying at a high temperature is preferably performed from about 8% by mass or less of residual solvent. Throughout, drying is generally performed at 40-250 ° C. In particular, drying at 40 to 160 ° C. is preferable.
  • tenter stretching apparatus When using a tenter stretching apparatus, it is preferable to use an apparatus that can independently control the film gripping length (distance from the start of gripping to the end of gripping) left and right by the left and right gripping means of the tenter. In the tenter process, it is also preferable to intentionally create sections having different temperatures in order to improve planarity.
  • the stretching treatment is preferably performed in the same manner as the melt casting film forming method.
  • the amount of residual solvent in the web is preferably 20 to 100% by mass at the start of the tenter, and drying is preferably performed while applying the tenter until the amount of residual solvent in the web is 10% by mass or less. More preferably, it is 5% by mass or less.
  • the drying temperature is preferably 30 to 160 ° C., more preferably 50 to 150 ° C., and most preferably 70 to 140 ° C.
  • the temperature distribution in the width direction of the atmosphere is small from the viewpoint of improving the uniformity of the film.
  • the temperature distribution in the width direction in the tenter process is preferably within ⁇ 5 ° C, and within ⁇ 2 ° C. Is more preferable, and within ⁇ 1 ° C. is most preferable.
  • Winding process This is a process in which the amount of residual solvent in the web becomes 2% by mass or less, and is taken up by the winder 37 as a film, and the dimensional stability is achieved by setting the residual solvent amount to 0.4% by mass or less. Can be obtained. It is particularly preferable to wind up at 0.00 to 0.10% by mass.
  • a generally used one may be used, and there are a constant torque method, a constant tension method, a taper tension method, a program tension control method with a constant internal stress, etc., and these may be used properly.
  • the film of the present invention can be particularly preferably used as a polarizer protective film for a large-sized liquid crystal display device or a liquid crystal display device for outdoor use as long as the above physical properties are satisfied.
  • a polarizing plate When using the film of this invention as a polarizer protective film, a polarizing plate can be produced by the method which uses a general cellulose ester as a polarizer protective film. That is, a water-based adhesive can be used for saponifying the polarizer protective film of the present invention and then bonding the polarizer.
  • the saponification treatment is preferably performed under conditions approximate to the following conditions as reference conditions.
  • conditions approximate to the following conditions can be preferably used for the purpose of speeding up the saponification treatment.
  • the saponification treatment is preferably performed within 360 hours after stretching. After this saponification treatment, a polarizer is bonded with an aqueous adhesive.
  • the water-based adhesive refers to an adhesive in which 50% by mass or more of the solvent is water, and examples thereof include polyvinyl alcohol-based aqueous adhesives, gelatin adhesives, vinyl-based latex adhesives, and water-based polyesters. A water-based adhesive is preferred.
  • These are usually preferably prepared to a solid content of 0.5 to 30% by mass.
  • the same adhesive as that when cellulose ester is used with the polarizer protective film is preferable.
  • the polarizer protective film of the present invention may be used, or another polarizer protective film may be used.
  • a commercially available cellulose ester film for example, Konica Minoltack KC8UX, KC4UX, KC5UX, KC8UY, KC4UY, KC12UR, KC8UCR-3, KC8UCR-4, KC8UCR-5, KC8UE, KC4FR-4, KC4FR-3, KC4FR-3, KC4FR-4 -1, KC8UY-HA, KC8UX-RHA, manufactured by Konica Minolta Opto Co., Ltd.) and the like are preferably used.
  • a polarizer which is a main component of a polarizing plate, is an element that allows only light of a plane of polarization in a certain direction to pass.
  • a typical polarizer currently known is a polyvinyl alcohol-based polarizing film, which is polyvinyl alcohol.
  • iodine is dyed on a system film and one in which dichroic dye is dyed.
  • a polyvinyl alcohol aqueous solution is formed into a film and dyed by uniaxial stretching or dyed or uniaxially stretched and then subjected to a durability treatment with a boron compound or the like.
  • liquid crystal display By incorporating the polarizing plate bonded with the film of the present invention into a liquid crystal display device, it is possible to produce various liquid crystal display devices with excellent visibility, but particularly for outdoor use such as large liquid crystal display devices and digital signage.
  • the liquid crystal display device is preferably used.
  • the polarizing plate according to the present invention is bonded to a liquid crystal cell via the adhesive layer or the like.
  • the polarizing plate according to the present invention includes a reflective type, a transmissive type, a transflective type LCD or a TN type, an STN type, an OCB type, a HAN type, a VA type (PVA type, MVA type), an IPS type (including an FFS type), and the like. It is preferably used in various drive LCDs. In particular, in a large-screen display device having a screen of 30 or more, especially 30 to 54, there is no white spot at the periphery of the screen and the effect is maintained for a long time.
  • Example 1 Preparation of acrylic particles AC1> A reactor with a reflux condenser with an internal volume of 60 liters was charged with 38.2 liters of ion-exchanged water and 111.6 g of sodium dioctylsulfosuccinate, and the temperature was raised to 75 ° C. in a nitrogen atmosphere while stirring at 250 rpm. The effect of oxygen was virtually eliminated. 0.36 g of APS was added, and after stirring for 5 minutes, a monomer mixture consisting of 1657 g of MMA, 21.6 g of BA, and 1.68 g of ALMA was added all at once, and after the exothermic peak was detected, the mixture was held for another 20 minutes to polymerize the innermost hard layer. Completed.
  • a small amount of the polymer latex thus obtained was collected, and the flat particle size was determined by the absorbance method, which was 0.10 ⁇ m.
  • the remaining latex was put into a 3% by mass sodium sulfate warm aqueous solution, salted out and coagulated, then dried and repeatedly dried to obtain acrylic particles AC1 having a three-layer structure.
  • MMA methyl methacrylate MA; methyl acrylate BA; n-butyl acrylate ALMA; allyl methacrylate PEGDA; polyethylene glycol diacrylate (molecular weight 200) n-OM; n-octyl mercaptan APS; ammonium persulfate ⁇ Preparation of polarizer protective film sample 101>
  • the produced dope solution was uniformly cast on a stainless steel band support at a temperature of 22 ° C. and a width of 2 m using a belt casting apparatus. With the stainless steel band support, the solvent was evaporated until the amount of residual solvent reached 100%, and peeling was performed from the stainless steel band support with a peeling tension of 162 N / m.
  • the web of the peeled resin composition was evaporated at 35 ° C., slit to 1.5 m width, and then stretched by 1.30 times (30%) in the width direction with a tenter at a drying temperature of 140 ° C. Dried. At this time, the residual solvent amount when starting stretching with a tenter was 10%.
  • samples 102 to 134 were prepared in the same manner as the sample 101 with the materials and conditions changed as shown in Table 1.
  • the materials used are as follows.
  • the friction coefficient after saponification was expressed as an average value of saponification treatment (1) and saponification treatment (2).
  • polarizing plate A 120 ⁇ m-thick long roll polyvinyl alcohol film was immersed in 100 parts by mass of an aqueous solution containing 1 part by mass of iodine and 4 parts by mass of boric acid, and stretched 6 times at 50 ° C. in the film forming direction to produce a polarizer.
  • polarization is performed so that the transmission axis of the polarizer is parallel to the in-plane slow axis of the saponified sample.
  • the saponified samples 101 to 134 were bonded to both sides of the child to produce polarizing plates 101 to 134. In this way, two types of polarizing plates having different saponification conditions were produced for each film.
  • Each polarizing plate was cut into a size of 5 cm ⁇ 7 cm.
  • the obtained cut pieces are each temporarily attached to the center of a 6 cm ⁇ 8 cm glass plate with an acrylic adhesive, and then pressed to completely remove bubbles between the pieces and the glass plate. Sticked to a glass plate.
  • test pieces thus prepared were placed vertically in a constant temperature and humidity oven set at 80 ° C. and 90% RH so as not to overlap each other and fixed to the support frame for 500 hours.
  • the adhesion of 134 films was measured.
  • the above-prepared polarizing plate was bonded so that the absorption axis was in the same direction as the polarizing plate that had been bonded in advance, and each liquid crystal display device was manufactured.

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Abstract

Provided is a polarizer protective film which has high suitability for saponification without impairing the tight adhesion of a polarizer, particularly in the case of quickly performing the saponification, has a stable film roll shape and causes little image nonuniformity. Also provided are a polarizing plate using said polarizer protective film and a method for producing the same. The polarizer protective film, which comprises an acrylic resin (A) and a cellulose ester resin (B) at a ratio by mass of 85:15 to 30:70, is characterized in that, when saponified, the coefficient of friction thereof after the saponification is smaller than the coefficient of friction thereof before the saponification.

Description

偏光子保護フィルム、それを用いた偏光板及びその製造方法Polarizer protective film, polarizing plate using the same, and method for producing the same
　本発明は、ケン化処理適性を向上させた偏光子保護フィルムに関し、より詳しくは、ケン化後のロールの巻き形状が良好であり、また、ケン化処理工程の迅速化に適し、更に耐久性に優れた偏光板が作製可能となる偏光子保護フィルムに関する。また、当該偏光子保護フィルムを用いた偏光板及びその製造方法に関する。 The present invention relates to a polarizer protective film with improved suitability for saponification treatment. More specifically, the wound shape of a roll after saponification is good, and it is suitable for speeding up the saponification treatment process, and further durable. The present invention relates to a polarizer protective film capable of producing an excellent polarizing plate. Moreover, it is related with the polarizing plate using the said polarizer protective film, and its manufacturing method.
　近年の技術の進歩により、液晶表示装置の大型化が加速するとともに、液晶表示装置の用途が多様化している。例えば、街頭や店頭に設置される大型ディスプレイとしての利用や、デジタルサイネージと呼ばれる表示機器を用いた公共の場における広告用ディスプレイへの利用等が挙げられる。 Recent advances in technology have accelerated the increase in size of liquid crystal display devices and diversified uses for liquid crystal display devices. For example, it can be used as a large display installed on a street or in a store, or used as an advertising display in a public place using a display device called digital signage.
　このような用途においては、屋外での利用が想定されるため、偏光子の高温高湿による劣化が問題になり、偏光子保護フィルムにはより高い耐高温高湿性が求められている。しかしながら、従来用いられているセルローストリアセテートフィルム等のセルロースエステルフィルムでは十分な耐高温高湿性を得ることは困難であった。 In such applications, since it is assumed to be used outdoors, deterioration of the polarizer due to high temperature and high humidity becomes a problem, and the polarizer protective film is required to have higher resistance to high temperature and high humidity. However, it has been difficult to obtain sufficient high-temperature and high-humidity resistance using a cellulose ester film such as a cellulose triacetate film that has been conventionally used.
　一方、アクリル樹脂の代表であるポリメチルメタクリレート（以下「ＰＭＭＡ」と略す。）は、低吸湿性に加え、優れた透明性や寸法安定性を示すことから、偏光子保護フィルムに好適に用いられていた。 On the other hand, polymethyl methacrylate (hereinafter abbreviated as “PMMA”), which is a representative of acrylic resin, exhibits excellent transparency and dimensional stability in addition to low hygroscopicity, and is therefore suitably used for a polarizer protective film. It was.
　しかし、ＰＭＭＡフィルムは、セルロースエステルフィルム等と比較した場合、割れやすく脆い性質があり、取扱いが困難で、特に大型の液晶表示装置用の偏光子保護フィルムを安定して製造することが困難であった。 However, the PMMA film, when compared with a cellulose ester film or the like, is fragile and brittle, and is difficult to handle. In particular, it is difficult to stably produce a polarizer protective film for a large liquid crystal display device. It was.
　上述の問題に対し、特許文献１では、アクリル樹脂とセルロース誘導体のブレンドによる樹脂組成物からなる光学フィルムが提案されている。 In response to the above-mentioned problem, Patent Document 1 proposes an optical film made of a resin composition made of a blend of an acrylic resin and a cellulose derivative.
　このブレンドした樹脂組成物による光学フィルムは、透明性が良好で、高温高湿下の耐久性を持ち、脆性に優れた偏光子保護フィルムではあるが、単に混合しただけではケン化適性が無く、偏光子との接着には、通常の偏光子保護フィルムであるセルロースエステルフィルムに使用するポリビニルアルコール系の水性接着剤とは異なる特別な接着剤が必要であり偏光板の生産面で大きく劣っていた。 The optical film made of this blended resin composition is a polarizer protective film that has good transparency, durability under high temperature and high humidity, and excellent brittleness. Adhesion with the polarizer required a special adhesive different from the polyvinyl alcohol-based aqueous adhesive used for the cellulose ester film, which is a normal polarizer protective film, and was greatly inferior in terms of production of polarizing plates. .
　現在この偏光板の生産性からセルロースエステルフィルムを用いたケン化による偏光子との接着は極めて有効な手法と考えられているが、今後は、更なる生産性向上を目的にケン化工程に迅速処理化が要望されている。しかしながら、単純にケン化処理の時間を短縮しただけでは、偏光子との密着性が劣化してしまう傾向が認められた。特に、偏光板の高温高湿下での耐久試験で密着性が一気に損なわれるとこが判明した。更に、ケン化後のロールフィルムが変形してしまうトラブルも多発し、ケン化処理の迅速化を偏光板の生産性に活かす方法が熱望されていた。 At present, due to the productivity of this polarizing plate, adhesion to a polarizer by saponification using a cellulose ester film is considered to be an extremely effective method, but in the future, the saponification process will be promptly promoted in order to further improve productivity. There is a demand for processing. However, it was recognized that the adhesiveness with the polarizer tends to be deteriorated simply by shortening the saponification time. In particular, it has been found that the adhesiveness is lost at a stretch in a durability test of the polarizing plate under high temperature and high humidity. Furthermore, troubles in which the roll film after saponification is deformed frequently occur, and a method for utilizing the speed of the saponification treatment for the productivity of the polarizing plate has been eagerly desired.
特開２００８－８８４１７号公報JP 2008-88417 A
　本発明は、上記課題にかんがみ成されたものであり、その解決課題は、ケン化処理適性に優れており、特にケン化の迅速処理においても偏光子の密着性が損なわれず、フィルムのロール形状が安定しており画像むらに優れた偏光子保護フィルムを提供することである。また、当該偏光子保護フィルムを用いた偏光板及びその製造方法を提供することである。 The present invention has been made in view of the above problems, and the solution is excellent in saponification suitability, in particular, the adhesiveness of the polarizer is not impaired even in the rapid processing of saponification, and the roll shape of the film Is to provide a polarizer protective film that is stable and excellent in image unevenness. Moreover, it is providing the polarizing plate using the said polarizer protective film, and its manufacturing method.
　本発明に係る上記課題は、以下の手段により解決することができる。 The above-mentioned problem according to the present invention can be solved by the following means.
　１．アクリル樹脂（Ａ）とセルロースエステル樹脂（Ｂ）を含有する偏光子保護フィルムであって、ケン化処理が施されたときに、当該ケン化処理後の摩擦係数が当該ケン化処理前の摩擦係数に対し小さいことを特徴とする偏光子保護フィルム。 1. A polarizer protective film containing an acrylic resin (A) and a cellulose ester resin (B), and when the saponification treatment is performed, the friction coefficient after the saponification treatment is the friction coefficient before the saponification treatment The polarizer protective film characterized by being small with respect to.
　２．前記アクリル樹脂（Ａ）と前記セルロースエステル樹脂（Ｂ）を８５：１５～３０：７０の質量比で含有し、かつ微粒子を含有することを特徴とする前記第１項に記載の偏光子保護フィルム。 2. 2. The polarizer protective film according to item 1, wherein the acrylic resin (A) and the cellulose ester resin (B) are contained at a mass ratio of 85:15 to 30:70 and fine particles are contained. .
　３．前記微粒子として、無機微粒子を含有することを特徴とする前記第２項に記載の偏光子保護フィルム。 3. 3. The polarizer protective film according to item 2, wherein the fine particles contain inorganic fine particles.
　４．前記微粒子として、無機微粒子とアクリル粒子を含有することを特徴とする前記第２項又は第３項に記載の偏光子保護フィルム。 4. 4. The polarizer protective film according to the second or third item, wherein the fine particles contain inorganic fine particles and acrylic particles.
　５．偏光子及び当該偏光子を挟む２枚の偏光子保護フィルムを具備した偏光板であって、当該偏光子保護フィルムのうち少なくとも１枚が前記第１項から第４項までのいずれか一項に記載の偏光子保護フィルムであることを特徴とする偏光板。 5. A polarizing plate comprising a polarizer and two polarizer protective films sandwiching the polarizer, wherein at least one of the polarizer protective films is in any one of items 1 to 4 above. A polarizing plate comprising the polarizer protective film according to claim.
　６．前記５に記載の偏光板を製造する偏光板の製造方法であって、前記第１項から第４項までのいずれか一項に記載の偏光子保護フィルムをケン化処理する工程を有することを特徴とする偏光板の製造方法。 6. It is a manufacturing method of the polarizing plate which manufactures the polarizing plate of said 5, Comprising: It has the process of saponifying the polarizer protective film as described in any one of said 1st term | claim to 4th term | claim. A method for producing a polarizing plate.
　７．前記ケン化処理する工程において、ケン化から乾燥直前の水洗までを１８０秒以内で処理することを特徴とする前記第６項に記載の偏光板の製造方法。 7. 7. The method for producing a polarizing plate according to claim 6, wherein in the saponification treatment, the treatment from saponification to water washing just before drying is performed within 180 seconds.
　本発明の上記手段により、ケン化処理適性に優れており、特にケン化の迅速処理においても偏光子の密着性が損なわれず、フィルムのロール形状が安定しており画像むらに優れた偏光子保護フィルムを提供することができる。また、当該偏光子保護フィルムを用いた偏光板及びその製造方法を提供することができる。 By the above means of the present invention, it is excellent in suitability for saponification treatment, and particularly in the rapid processing of saponification, the adhesiveness of the polarizer is not impaired, the roll shape of the film is stable, and the polarizer protection excellent in image unevenness A film can be provided. Moreover, the polarizing plate using the said polarizer protective film and its manufacturing method can be provided.
　本発明の偏光子保護フィルム（以下において、適宜、「光学フィルム」又は単に「フィルム」ともいう。）は、アクリル樹脂（Ａ）とセルロースエステル樹脂（Ｂ）を含有する偏光子保護フィルムであって、ケン化処理が施されたときに、当該ケン化処理後の摩擦係数が当該ケン化処理前の摩擦係数に対し小さいことを特徴とする。この特徴は、請求項１から請求項７までの請求項に係る発明に共通する技術的特徴である。 The polarizer protective film of the present invention (hereinafter also referred to as “optical film” or simply “film” as appropriate) is a polarizer protective film containing an acrylic resin (A) and a cellulose ester resin (B). When the saponification treatment is performed, the friction coefficient after the saponification treatment is smaller than the friction coefficient before the saponification treatment. This feature is a technical feature common to the inventions according to claims 1 to 7.
　本発明では、ケン化による接着性を達成するためには、ケン化後の偏光子保護フィルムの表面状態が極めて重要であり、具体的には表面状態の凹凸を増加することが必要であることから、例えば、微粒子を添加する方法、延伸倍率や延伸速度を調節することで表面に微細な割れを形成する方法、更に表面に微細な凹凸を有しているロールを押し当てフィルム上に凹凸を転写する方法などが挙げられる。また、偏光子との接着に適する表面の分子状態を形成するために、親水性を有する化合物や、好ましい可塑剤などの添加剤によっても達成できる。更に、ケン化反応で生成する残留物による経時における接着性の阻害を抑制するために、セルロースエステルの適切な置換度や分子量、更にアクリル樹脂との好ましい比率によっても達成される。 In the present invention, in order to achieve adhesion by saponification, the surface state of the polarizer protective film after saponification is extremely important, and specifically, it is necessary to increase the unevenness of the surface state. From, for example, a method of adding fine particles, a method of forming fine cracks on the surface by adjusting the draw ratio and the drawing speed, and further pressing the roll having fine unevenness on the surface to make unevenness on the film Examples include a method of transferring. Moreover, in order to form the surface molecular state suitable for adhesion | attachment with a polarizer, it can also achieve with additives, such as a compound which has hydrophilic property, and a preferable plasticizer. Furthermore, in order to suppress the inhibition of adhesiveness over time due to the residue generated by the saponification reaction, it is also achieved by an appropriate substitution degree and molecular weight of the cellulose ester and a preferable ratio with the acrylic resin.
　本発明の実施態様としては、本発明の効果発現の観点から、前記アクリル樹脂（Ａ）と前記セルロースエステル樹脂（Ｂ）を８５：１５～３０：７０の質量比で含有し、かつ微粒子を含有することが好ましい。また、前記微粒子として、無機微粒子を含有すること、又は、無機微粒子とアクリル粒子を含有する態様であることが好ましい。 As an embodiment of the present invention, the acrylic resin (A) and the cellulose ester resin (B) are contained in a mass ratio of 85:15 to 30:70 and fine particles are included from the viewpoint of manifesting the effects of the present invention. It is preferable to do. Further, it is preferable that the fine particles contain inorganic fine particles, or an aspect containing inorganic fine particles and acrylic particles.
　本発明の偏光子保護フィルムを偏光板に用いる場合、偏光子及び当該偏光子を挟む２枚の偏光子保護フィルムを具備した偏光板において、当該偏光子保護フィルムのうち少なくとも１枚が本発明の偏光子保護フィルムであることが好ましい。 When the polarizer protective film of the present invention is used for a polarizing plate, in the polarizing plate including the polarizer and the two polarizer protective films sandwiching the polarizer, at least one of the polarizer protective films is of the present invention. It is preferable that it is a polarizer protective film.
　当該偏光板を製造する偏光板の製造方法としては、本発明の偏光子保護フィルムをケン化処理する工程を有する態様の製造方法であることが好ましい。また、この場合、前記ケン化処理する工程において、ケン化から乾燥直前の水洗までを１８０秒以内で処理する態様であることが好ましい。 The production method of the polarizing plate for producing the polarizing plate is preferably a production method having a step of saponifying the polarizer protective film of the present invention. In this case, it is preferable that the saponification treatment is performed within 180 seconds from saponification to washing immediately before drying.
　以下、本発明とその構成要素、及び本発明を実施するための形態・態様について詳細な説明をする。 Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail.
　〈ケン化処理〉
　本願でいう「ケン化処理」とは、フィルムのエステル構造部分を元の構成要素である酸とアルコールに分解するため、アルカリを加えて酸の塩とアルコールに分解する化学処理をいう。本発明においては、従来公知の種々のケン化処理法を採用できるが、下記の方法に準拠した方法であることが好ましい。 <Saponification>
The “saponification treatment” as used in the present application refers to a chemical treatment in which an ester is decomposed into an acid salt and an alcohol by adding an alkali in order to decompose the ester structure portion of the film into the original constituent acid and alcohol. In the present invention, various conventionally known saponification treatment methods can be adopted, but a method based on the following method is preferred.
　（１）アルカリ液に浸漬する法
　アルカリ液の中にフィルムを適切な条件で浸漬して、フィルム全表面のアルカリと反応性を有する全ての面をケン化処理する手法であり、特別な設備を必要としないため、コストの観点で好ましい。アルカリ液は、水酸化カリウム水溶液、水酸化ナトリウム水溶液などが好ましい。好ましい濃度は０．５～３ｍｏｌ／Ｌであり、特に好ましくは１～２．５ｍｏｌ／Ｌである。好ましいアルカリ液の液温は３０～７５℃、特に好ましくは３５～６０℃である。また好ましい浸漬時間は、２０秒～３００秒、特に好ましくは３０～１００秒である。 (1) Method of immersing in alkaline solution This is a method of saponifying all surfaces that are reactive with alkali on the entire surface of the film by immersing the film in an alkaline solution under appropriate conditions. Since it is not necessary, it is preferable from the viewpoint of cost. The alkaline solution is preferably a potassium hydroxide aqueous solution or a sodium hydroxide aqueous solution. A preferred concentration is 0.5 to 3 mol / L, particularly preferably 1 to 2.5 mol / L. The liquid temperature of the alkaline solution is preferably 30 to 75 ° C, particularly preferably 35 to 60 ° C. A preferable immersion time is 20 seconds to 300 seconds, particularly preferably 30 to 100 seconds.
　前記のケン化条件の組合せは、比較的穏和な条件同士の組合せであることが好ましいが、光散乱フィルムや反射防止フィルムの素材や構成、目標とする接触角によって設定することができる。 The combination of the saponification conditions is preferably a combination of relatively mild conditions, but can be set according to the material and configuration of the light scattering film and the antireflection film, and the target contact angle.
　アルカリ液に浸漬した後は、フィルムの中にアルカリ成分が残留しないように、水で十分に水洗したり、希薄な酸に浸漬してアルカリ成分を中和することが好ましい。 After being immersed in an alkali solution, it is preferable to sufficiently wash with water or neutralize the alkali component by immersing in a dilute acid so that the alkali component does not remain in the film.
　親水化された表面は、ポリビニルアルコールを主成分とする接着層との接着性を改良するのに有効である。 The hydrophilized surface is effective for improving the adhesion with an adhesive layer mainly composed of polyvinyl alcohol.
　フィルムが受けるアルカリによるケン化の程度の指標として、水に対する接触角を用いた場合、本発明のフィルムでは、偏光膜との接着性、物理強度等の観点から、１０～５５度の範囲内であることが好ましい。さらに、好ましくは３０～５０度であり、特に好ましくは４０～５０度の範囲内である。 When the contact angle with water is used as an indicator of the degree of saponification by the alkali received by the film, the film of the present invention has a range of 10 to 55 degrees from the viewpoint of adhesion to the polarizing film, physical strength, and the like. Preferably there is. Further, it is preferably 30 to 50 degrees, and particularly preferably in the range of 40 to 50 degrees.
　（２）アルカリ液を塗布する方法
　上述の浸漬法におけるフィルムの各機能層へのアルカリケン化の影響を回避する手段として、適切な条件でアルカリ液を防眩層や低屈折率層等の機能層を有する表面と反対側の表面のみに塗布、加熱、水洗、乾燥するアルカリ液塗布法が好ましい。 (2) Method of applying alkali solution As a means for avoiding the influence of alkali saponification on each functional layer of the film in the above-mentioned dipping method, the alkali solution functions as an antiglare layer or a low refractive index layer under appropriate conditions. An alkaline liquid coating method in which coating, heating, washing and drying are performed only on the surface opposite to the surface having the layer is preferable.
　なお、この場合の塗布とは、ケン化を行う面に対してのみアルカリ液などを接触させることを意味し、塗布以外にも噴霧、液を含んだベルト等に接触させる、などによって行われることも含む。これらの方法を採ることにより、別途、アルカリ液を塗布する設備、工程が必要となるため、コストの観点では（１）の浸漬法に劣る。一方で、ケン化処理を施す面にのみアルカリ液が接触するため、反対側の面にはアルカリ液に弱い素材を用いた層を有することができる。例えば、蒸着膜やゾル－ゲル膜では、アルカリ液によって、腐食、溶解、剥離など様々な影響が起こるため、浸漬法では設けることが望ましくないが、この塗布法では液と接触しないため問題なく使用することが可能である。 The application in this case means that an alkaline liquid or the like is brought into contact only with the surface to be saponified, and is performed by spraying or contacting a belt containing the liquid in addition to the application. Including. By adopting these methods, a separate facility and process for applying an alkaline solution are required, which is inferior to the immersion method (1) from the viewpoint of cost. On the other hand, since the alkali solution contacts only the surface to be saponified, the opposite surface can have a layer using a material that is weak against the alkali solution. For example, vapor deposition films and sol-gel films have various effects such as corrosion, dissolution, and peeling due to alkali solution, so it is not desirable to use the immersion method. Is possible.
　前記（１）及び（２）のどちらのケン化方法においても、ロール状の支持体から巻き出して各層を形成後に行うことができるため、フィルム製造工程の後に加えて一連の操作で行ってもよい。更に、同様に巻き出した支持体からなる偏光板との張り合わせ工程もあわせて連続で行うことにより、枚葉で同様の操作をするよりもより効率よく偏光板を作製することができる。 In both the saponification methods (1) and (2), since each layer can be formed after being unwound from a roll-shaped support, it can be carried out by a series of operations in addition to the film manufacturing process. Good. Furthermore, the polarizing plate can be produced more efficiently than the same operation with a single wafer by continuously performing the pasting step with the polarizing plate comprising the support that has been unwound in the same manner.
　＜摩擦係数＞
　本発明では、ケン化後の摩擦係数がケン化前の摩擦係数に対し小さいことを最も特徴としているが、これは表面に凹凸を形成し接着面積を増加させることが有効であることを示していることと考えている。同様に、偏光子とフィルムの界面に微粒子が存在することがより好ましい環境を整えると考えている。以上のように、ケン化後のフィルム表面の凹凸を増す設計が有効と成りえる。本発明においては、フィルムの接触面同士の間の摩擦係数を、ＪＩＳ－Ｋ－７１２５（１９８７）に規定する方法で測定する。 <Friction coefficient>
The present invention is most characterized in that the coefficient of friction after saponification is smaller than the coefficient of friction before saponification, which indicates that it is effective to increase the adhesion area by forming irregularities on the surface. I believe that. Similarly, it is considered that the presence of fine particles at the interface between the polarizer and the film provides a more preferable environment. As described above, a design that increases the unevenness of the film surface after saponification can be effective. In the present invention, the coefficient of friction between the contact surfaces of the film is measured by the method defined in JIS-K-7125 (1987).
　〈アクリル樹脂（Ａ）〉
　本発明に用いられるアクリル樹脂には、メタクリル樹脂も含まれる。樹脂としては特に制限されるものではないが、メチルメタクリレート単位５０～９９質量％、およびこれと共重合可能な他の単量体単位１～５０質量％からなるものが好ましい。 <Acrylic resin (A)>
The acrylic resin used in the present invention includes a methacrylic resin. The resin is not particularly limited, but a resin comprising 50 to 99% by mass of methyl methacrylate units and 1 to 50% by mass of other monomer units copolymerizable therewith is preferable.
　共重合可能な他の単量体としては、アルキル数の炭素数が２～１８のアルキルメタクリレート、アルキル数の炭素数が１～１８のアルキルアクリレート、アクリル酸、メタクリル酸等のα，β－不飽和酸、マレイン酸、フマル酸、イタコン酸等の不飽和基含有二価カルボン酸、スチレン、α－メチルスチレン等の芳香族ビニル化合物、アクリロニトリル、メタクリロニトリル等のα，β－不飽和ニトリル、無水マレイン酸、マレイミド、Ｎ－置換マレイミド、グルタル酸無水物等、アクリロイルモルフォリン等のアクリルアミド誘導体等が挙げられ、これらは１種または２種以上の単量体を併用して用いることができる。 Examples of other copolymerizable monomers include alkyl methacrylates having 2 to 18 alkyl carbon atoms, alkyl acrylates having 1 to 18 carbon atoms, alkyl acrylates such as acrylic acid and methacrylic acid. Unsaturated group-containing divalent carboxylic acids such as saturated acid, maleic acid, fumaric acid and itaconic acid, aromatic vinyl compounds such as styrene and α-methylstyrene, α, β-unsaturated nitriles such as acrylonitrile and methacrylonitrile, Examples thereof include maleic anhydride, maleimide, N-substituted maleimide, glutaric anhydride, and acrylamide derivatives such as acryloylmorpholine. These may be used alone or in combination of two or more monomers.
　これらの中でも、共重合体の耐熱分解性や流動性の観点から、メチルアクリレート、エチルアクリレート、ｎ－プロピルアクリレート、ｎ－ブチルアクリレート、ｓ－ブチルアクリレート、２－エチルヘキシルアクリレート等が好ましく、メチルアクリレートやｎ－ブチルアクリレートが特に好ましく用いられる。 Among these, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, 2-ethylhexyl acrylate, and the like are preferable from the viewpoint of thermal decomposition resistance and fluidity of the copolymer. n-Butyl acrylate is particularly preferably used.
　本発明のフィルムに用いられるアクリル樹脂（Ａ）の重量平均分子量（Ｍｗ）は、１１０，０００～１，０００，０００の範囲内であることが好ましく、１４０，０００～６００，０００の範囲内であることがより好ましく、２００，０００～４００，０００の範囲であることが特に好ましい。 The weight average molecular weight (Mw) of the acrylic resin (A) used in the film of the present invention is preferably in the range of 110,000 to 1,000,000, and in the range of 140,000 to 600,000. More preferably, it is particularly preferably in the range of 200,000 to 400,000.
　本発明に係るアクリル樹脂の重量平均分子量は、ゲルパーミエーションクロマトグラフィーにより測定することができる。測定条件は以下の通りである。 The weight average molecular weight of the acrylic resin according to the present invention can be measured by gel permeation chromatography. The measurement conditions are as follows.
　溶媒：　　　メチレンクロライド
　カラム：　　Ｓｈｏｄｅｘ　Ｋ８０６、Ｋ８０５、Ｋ８０３Ｇ（昭和電工（株）製を３本接続して使用した）
　カラム温度：２５℃
　試料濃度：　０．１質量％
　検出器：　　ＲＩ　Ｍｏｄｅｌ　５０４（ＧＬサイエンス社製）
　ポンプ：　　Ｌ６０００（日立製作所（株）製）
　流量：　　　１．０ｍｌ／ｍｉｎ
　校正曲線：　標準ポリスチレンＳＴＫ　ｓｔａｎｄａｒｄ　ポリスチレン（東ソー（株）製）Ｍｗ＝２，８００，０００～５００迄の１３サンプルによる校正曲線を使用した。１３サンプルは、ほぼ等間隔に用いることが好ましい。 Solvent: Methylene chloride Column: Shodex K806, K805, K803G (Used by connecting three Showa Denko Co., Ltd.)
Column temperature: 25 ° C
Sample concentration: 0.1% by mass
Detector: RI Model 504 (manufactured by GL Sciences)
Pump: L6000 (manufactured by Hitachi, Ltd.)
Flow rate: 1.0ml / min
Calibration curve: Standard polystyrene STK standard polystyrene (manufactured by Tosoh Corp.) Mw = 2,800,000-500 calibration curves with 13 samples were used. The 13 samples are preferably used at approximately equal intervals.
　本発明におけるアクリル樹脂（Ａ）の製造方法としては、特に制限は無く、懸濁重合、乳化重合、塊状重合、あるいは溶液重合等の公知の方法のいずれを用いても良い。ここで、重合開始剤としては、通常のパーオキサイド系、アゾ系、レドックス系のものを用いることができる。重合温度については、懸濁または乳化重合では３０～１００℃、塊状または溶液重合では８０～１６０℃で実施しうる。得られた共重合体の還元粘度を制御するために、アルキルメルカプタン等を連鎖移動剤として用いて重合を実施することもできる。 The production method of the acrylic resin (A) in the present invention is not particularly limited, and any known method such as suspension polymerization, emulsion polymerization, bulk polymerization, or solution polymerization may be used. Here, as a polymerization initiator, a normal peroxide type, azo type, or redox type can be used. The polymerization temperature may be 30 to 100 ° C. for suspension or emulsion polymerization, and 80 to 160 ° C. for bulk or solution polymerization. In order to control the reduced viscosity of the obtained copolymer, polymerization can be carried out using alkyl mercaptan or the like as a chain transfer agent.
　本発明に係るアクリル樹脂としては、市販のものも使用することができる。例えば、デルペット６０Ｎ、８０Ｎ（旭化成ケミカルズ（株）製）、ダイヤナールＢＲ５２、ＢＲ８０，ＢＲ８３，ＢＲ８５，ＢＲ８８（三菱レイヨン（株）製）、ＫＴ７５（電気化学工業（株）製）等が挙げられる。アクリル樹脂は２種以上を併用することもできる。 Commercially available acrylic resins can be used as the acrylic resin according to the present invention. For example, Delpet 60N, 80N (Asahi Kasei Chemicals Co., Ltd.), Dialal BR52, BR80, BR83, BR85, BR88 (Mitsubishi Rayon Co., Ltd.), KT75 (Electrochemical Industry Co., Ltd.) and the like can be mentioned. . Two or more acrylic resins can be used in combination.
　〈セルロースエステル樹脂（Ｂ）〉
　本発明に係るセルロースエステル樹脂（Ｂ）は、特に脆性の改善やアクリル樹脂（Ａ）と相溶させたときの透明性の観点から、アシル基の総置換度（Ｔ）が２．０～３．０、炭素数が３～７のアシル基の置換度が１．２～３．０であることが好ましく、より好ましくはアシル基の総置換度が２．５～３．０、炭素数３～７のアシル基の置換度は２．０～３．０である。 <Cellulose ester resin (B)>
The cellulose ester resin (B) according to the present invention has a total acyl group substitution degree (T) of 2.0 to 3 particularly from the viewpoint of improvement in brittleness and transparency when it is compatible with the acrylic resin (A). The substitution degree of the acyl group having 0.0 and 3 to 7 carbon atoms is preferably 1.2 to 3.0, more preferably the total substitution degree of the acyl group is 2.5 to 3.0 and 3 carbon atoms. The substitution degree of the acyl group of ˜7 is 2.0 to 3.0.
　セルロースエステル樹脂（Ｂ）のアシル基の総置換度が２．０を下回る場合には、アクリル樹脂（Ａ）とセルロースエステル樹脂（Ｂ）が十分に相溶せずアクリルフィルムとして用いる場合にヘイズが問題となることがある。また、アシル基の総置換度が２．０以上であっても、炭素数が３～７のアシル基の置換度が１．２を下回る場合は、やはり十分な相溶性が得られないか、脆性が低下することとなる。 When the total substitution degree of the acyl group of the cellulose ester resin (B) is less than 2.0, the acrylic resin (A) and the cellulose ester resin (B) are not sufficiently compatible with each other and used as an acrylic film. May be a problem. In addition, even when the total substitution degree of the acyl group is 2.0 or more, if the substitution degree of the acyl group having 3 to 7 carbon atoms is less than 1.2, still sufficient compatibility cannot be obtained, Brittleness will decrease.
　本発明において前記アシル基は、脂肪族アシル基であっても、芳香族アシル基であってもよい。脂肪族アシル基の場合は、直鎖であっても分岐していても良く、さらに置換基を有してもよい。アシル基で置換されていない部分は通常水酸基として存在しているものである。これらは公知の方法で合成することができる。 In the present invention, the acyl group may be an aliphatic acyl group or an aromatic acyl group. In the case of an aliphatic acyl group, it may be linear or branched and may further have a substituent. The portion that is not substituted with an acyl group usually exists as a hydroxyl group. These can be synthesized by known methods.
　本発明に係るセルロースエステル樹脂（Ｂ）としては、特にセルロースアセテートプロピオネート、セルロースアセテートブチレート、セルロースアセテートベンゾエート、セルロースプロピオネート、セルロースブチレートから選ばれる少なくとも一種であることが好ましい。これらの中で特に好ましいセルロースエステル樹脂は、セルロースアセテートプロピオネート、セルロースプロピオネートである。 The cellulose ester resin (B) according to the present invention is preferably at least one selected from cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate benzoate, cellulose propionate, and cellulose butyrate. Among these, cellulose ester resins that are particularly preferable are cellulose acetate propionate and cellulose propionate.
　なお、アセチル基の置換度や他のアシル基の置換度は、ＡＳＴＭ－Ｄ８１７－９６に規定の方法により求めたものである。 Incidentally, the substitution degree of the acetyl group and the substitution degree of other acyl groups were determined by the method prescribed in ASTM-D817-96.
　本発明に係るセルロースエステル樹脂の重量平均分子量（Ｍｗ）は、特にアクリル樹脂（Ａ）との相溶性、脆性の改善の観点から７５，０００以上であることが好ましく、７５，０００～２４０，０００の範囲であることがより好ましく、１００，０００～２４０，０００の範囲内であることがさらに好ましく、１６０，０００～２４０，０００のものが特に好ましい。本発明では２種以上のセルロース樹脂を混合して用いることもできる。 The weight average molecular weight (Mw) of the cellulose ester resin according to the present invention is preferably 75,000 or more, particularly from the viewpoint of improvement in compatibility with the acrylic resin (A) and brittleness, and 75,000 to 240,000. Is more preferably in the range of 100,000 to 240,000, particularly preferably 160,000 to 240,000. In the present invention, two or more kinds of cellulose resins can be mixed and used.
　本発明のアクリルフィルムにおいて、アクリル樹脂（Ａ）とセルロースエステル樹脂（Ｂ）は、本発明の効果発現の観点から、８５：１５～３０：７０の質量比で用いられることが好ましく、さらに好ましくは８０：２０～４０：６０であり、最も好ましくは８０：２０～５０：５０である。 In the acrylic film of the present invention, the acrylic resin (A) and the cellulose ester resin (B) are preferably used in a mass ratio of 85:15 to 30:70, more preferably from the viewpoint of manifesting the effects of the present invention. 80:20 to 40:60, most preferably 80:20 to 50:50.
　本発明のフィルムにおいては、アクリル樹脂（Ａ）とセルロースエステル樹脂（Ｂ）が相溶状態で含有されることが好ましい。光学フィルムとして必要とされる物性や品質を、異なる樹脂を相溶させることで相互に補うことにより達成している。 In the film of the present invention, the acrylic resin (A) and the cellulose ester resin (B) are preferably contained in a compatible state. The physical properties and quality required for an optical film are achieved by supplementing each other by dissolving different resins.
　アクリル樹脂（Ａ）とセルロースエステル樹脂（Ｂ）が相溶状態となっているかどうかは、例えばガラス転移温度Ｔｇにより判断することが可能である。 Whether the acrylic resin (A) and the cellulose ester resin (B) are in a compatible state can be determined by, for example, the glass transition temperature Tg.
　例えば、両者の樹脂のガラス転移温度が異なる場合、両者の樹脂を混合したときは、各々の樹脂のガラス転移温度が存在するため混合物のガラス転移温度は２つ以上存在するが、両者の樹脂が相溶したときは、各々の樹脂固有のガラス転移温度が消失し、１つのガラス転移温度となって相溶した樹脂のガラス転移温度となる。 For example, when the two resins have different glass transition temperatures, when the two resins are mixed, there are two or more glass transition temperatures for each resin because there is a glass transition temperature for each resin. When they are compatible, the glass transition temperature specific to each resin disappears and becomes one glass transition temperature, which is the glass transition temperature of the compatible resin.
　尚、ここでいうガラス転移温度とは、示差走査熱量測定器（Ｐｅｒｋｉｎ　Ｅｌｍｅｒ社製ＤＳＣ－７型）を用いて、昇温速度２０℃／分で測定し、ＪＩＳ　Ｋ７１２１（１９８７）に従い求めた中間点ガラス転移温度（Ｔｍｇ）とする。 The glass transition temperature referred to here is an intermediate value determined according to JIS K7121 (1987) using a differential scanning calorimeter (DSC-7 model manufactured by Perkin Elmer) at a heating rate of 20 ° C./min. The point glass transition temperature (Tmg).
　本発明のフィルムには、本発明の効果を損なわない範囲でアクリル樹脂（Ａ）、セルロースエステル樹脂（Ｂ）以外の樹脂や添加剤を含有しても良い。 The film of the present invention may contain resins and additives other than the acrylic resin (A) and the cellulose ester resin (B) as long as the effects of the present invention are not impaired.
　本発明では、偏光子と偏光子保護フィルムとの接着性の改善において微粒子が好ましく用いられる。本発明で用いられる微粒子としては、無機微粒子または有機微粒子のどちらでも良い。有機微粒子としては、例えば、シリコーン樹脂、フッ素樹脂及びアクリル系樹脂等のポリマーが好ましく、中でもアクリル粒子が好ましく用いられる。 In the present invention, fine particles are preferably used for improving the adhesion between the polarizer and the polarizer protective film. The fine particles used in the present invention may be either inorganic fine particles or organic fine particles. As the organic fine particles, for example, polymers such as silicone resin, fluororesin and acrylic resin are preferable, and acrylic particles are preferably used.
　本発明では、ケン化後の巻き形状に優れ長尺巻きが可能となる、無機微粒子が好ましく使用されるが、無機微粒子と有機微粒子との併用で偏光板の接着性がより強固となり最も好ましい。 In the present invention, inorganic fine particles that are excellent in the wound shape after saponification and enable long winding are preferably used, but the combined use of inorganic fine particles and organic fine particles is most preferable because the adhesiveness of the polarizing plate becomes stronger.
　〈無機微粒子〉
　無機微粒子としては、珪素を含む化合物、二酸化珪素、酸化アルミニウム、酸化ジルコニウム、炭酸カルシウム、タルク、クレイ、焼成カオリン、焼成ケイ酸カルシウム、水和ケイ酸カルシウム、ケイ酸アルミニウム、ケイ酸マグネシウム及びリン酸カルシウム等が好ましく、さらに好ましくは、ケイ素を含む無機微粒子や酸化ジルコニウムである。 <Inorganic fine particles>
Inorganic fine particles include silicon-containing compounds, silicon dioxide, aluminum oxide, zirconium oxide, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, calcium phosphate, etc. More preferred are inorganic fine particles containing silicon and zirconium oxide.
　これらの中でも、セルロースエステルと屈折率が近いので透明性（ヘイズ）に優れる二酸化珪素が特に好ましく用いられる。二酸化珪素の具体例としては、アエロジル２００Ｖ、アエロジルＲ９７２Ｖ、アエロジルＲ９７２、Ｒ９７４、Ｒ８１２、２００、３００、Ｒ２０２、ＯＸ５０、ＴＴ６００（以上日本アエロジル（株）製）、シーホスターＫＥＰ－１０、シーホスターＫＥＰ－３０、シーホスターＫＥＰ－５０、シーホスターＫＥ－Ｐ１００（以上、株式会社日本触媒製）、サイロホービック１００（富士シリシア製）、ニップシールＥ２２０Ａ（日本シリカ工業製）、アドマファインＳＯ（アドマテックス製）等の商品名を有する市販品などが好ましく使用できる。 Of these, silicon dioxide is particularly preferably used since it has a refractive index close to that of cellulose ester and is excellent in transparency (haze). Specific examples of silicon dioxide include Aerosil 200V, Aerosil R972V, Aerosil R972, R974, R812, 200, 300, R202, OX50, TT600 (above Nippon Aerosil Co., Ltd.), Sea Hoster KEP-10, Sea Hoster KEP-30, Product names such as Seahoster KEP-50, Seahoster KE-P100 (above, Nippon Shokubai Co., Ltd.), Silo Hovic 100 (Fuji Silysia), Nip Seal E220A (Nihon Silica Kogyo), Admafine SO (Admatechs) A commercially available product having the above can be preferably used.
　無機微粒子の形状としては、不定形、針状、扁平、球状等特に制限なく使用できるが、特に球状の粒子を用いると得られるフィルムの透明性が良好にできるので好ましい。粒子の大きさは、可視光の波長に近いと光が散乱し、透明性が悪くなるので、可視光の波長より小さいことが好ましく、さらに可視光の波長の１／２以下であることが好ましい。 The shape of the inorganic fine particles can be used without particular limitation, such as indefinite shape, needle shape, flat shape, spherical shape, etc. However, the use of spherical particles is particularly preferable because the transparency of the resulting film can be improved. When the particle size is close to the wavelength of visible light, light is scattered and the transparency is deteriorated. Therefore, the particle size is preferably smaller than the wavelength of visible light, and more preferably ½ or less of the wavelength of visible light. .
　粒子の大きさは、０．０５μｍから３．０μｍの範囲であることが好ましい。 The particle size is preferably in the range of 0.05 μm to 3.0 μm.
　これらの微粒子は、単独でも二種以上併用しても使用できる。粒径や形状（例えば針状と球状など）の異なる粒子を併用することで高度に透明性と滑り性を両立させることもできる。これらの微粒子は光学フィルム全体の０．０１～５質量％含有させることができる。なお、粒子の大きさとは、粒子が１次粒子の凝集体の場合は凝集体の大きさを意味する。また、粒子が球状でない場合は、その投影面積に相当する円の直径を意味する。 These fine particles can be used alone or in combination of two or more. By using particles having different particle sizes and shapes (for example, acicular and spherical), both transparency and slipperiness can be made highly compatible. These fine particles can be contained in an amount of 0.01 to 5% by mass of the entire optical film. The particle size means the size of the aggregate when the particle is an aggregate of primary particles. Moreover, when a particle is not spherical, it means the diameter of a circle corresponding to the projected area.
　〈アクリル粒子〉
　本発明に係るアクリル粒子は、前記アクリル樹脂（Ａ）及びセルロースエステル樹脂（Ｂ）とアクリル樹脂含有フィルム中で粒子の状態で存在すること（非相溶状態ともいう）が特徴である。 <Acrylic particles>
The acrylic particles according to the present invention are characterized by being present in the state of particles in the acrylic resin (A), the cellulose ester resin (B) and the acrylic resin-containing film (also referred to as incompatible state).
　上記アクリル粒子は、例えば、作製したアクリル樹脂含有フィルムを所定量採取し、溶媒に溶解させて攪拌し、充分に溶解・分散させたところで、アクリル粒子の平均粒子径未満の孔径を有するＰＴＦＥ製のメンブレンフィルターを用いて濾過し、濾過捕集された不溶物の重さが、アクリル樹脂含有フィルムに添加したアクリル粒子の９０質量％以上あることが好ましい。 The acrylic particles are obtained by, for example, collecting a predetermined amount of the prepared acrylic resin-containing film, dissolving in a solvent, stirring, and sufficiently dissolving and dispersing the PTFE film having a pore diameter less than the average particle diameter of the acrylic particles. It is preferable that the weight of the insoluble matter filtered and collected using the membrane filter is 90% by mass or more of the acrylic particles added to the acrylic resin-containing film.
　本発明に用いられるアクリル粒子は特に限定されるものではないが、２層以上の層構造を有するアクリル粒子であることが好ましく、特に下記多層構造アクリル系粒状複合体であることが好ましい。 The acrylic particles used in the present invention are not particularly limited, but are preferably acrylic particles having a layer structure of two or more layers, and particularly preferably the following multilayer structure acrylic granular composite.
　多層構造アクリル系粒状複合体とは、中心部から外周部に向かって最内硬質層重合体、ゴム弾性を示す架橋軟質層重合体、および最外硬質層重合体が、層状に重ね合わされてなる構造を有する粒子状のアクリル系重合体を言う。 The multilayer structure acrylic granular composite is formed by laminating an innermost hard layer polymer, a cross-linked soft layer polymer exhibiting rubber elasticity, and an outermost hard layer polymer from the center to the outer periphery. This refers to a particulate acrylic polymer having a structure.
　本発明に係るアクリル系樹脂組成物に用いられる多層構造アクリル系粒状複合体の好ましい態様としては、以下の様なものが挙げられる。（ａ）メチルメタクリレート８０～９８．９質量％、アルキル基の炭素数が１～８のアルキルアクリレート１～２０質量％、および多官能性グラフト剤０．０１～０．３質量％からなる単量体混合物を重合して得られる最内硬質層重合体、（ｂ）上記最内硬質層重合体の存在下に、アルキル基の炭素数が４～８のアルキルアクリレート７５～９８．５質量％、多官能性架橋剤０．０１～５質量％および多官能性グラフト剤０．５～５質量％からなる単量体混合物を重合して得られる架橋軟質層重合体、（ｃ）上記最内硬質層および架橋軟質層からなる重合体の存在下に、メチルメタクリレート８０～９９質量％とアルキル基の炭素数が１～８であるアルキルアクリレート１～２０質量％とからなる単量体混合物を重合して得られる最外硬層重合体、よりなる３層構造を有し、かつ得られた３層構造重合体が最内硬質層重合体（ａ）５～４０質量％、軟質層重合体（ｂ）３０～６０質量％、および最外硬質層重合体（ｃ）２０～５０質量％からなり、アセトンで分別したときに不溶部があり、その不溶部のメチルエチルケトン膨潤度が１．５～４．０であるアクリル系粒状複合体、が挙げられる。 Preferred embodiments of the multilayer structure acrylic granular composite used in the acrylic resin composition according to the present invention include the following. (A) Monomer comprising 80 to 98.9% by weight of methyl methacrylate, 1 to 20% by weight of alkyl acrylate having 1 to 8 carbon atoms in the alkyl group, and 0.01 to 0.3% by weight of polyfunctional grafting agent (B) 75 to 98.5% by mass of an alkyl acrylate having 4 to 8 carbon atoms in the presence of the innermost hard layer polymer in the presence of the innermost hard layer polymer, A crosslinked soft layer polymer obtained by polymerizing a monomer mixture comprising 0.01 to 5% by mass of a multifunctional crosslinking agent and 0.5 to 5% by mass of a multifunctional grafting agent; (c) the innermost hard In the presence of a polymer comprising a layer and a crosslinked soft layer, a monomer mixture comprising 80 to 99% by mass of methyl methacrylate and 1 to 20% by mass of alkyl acrylate having 1 to 8 carbon atoms in the alkyl group is polymerized. Outermost hard layer weight And the obtained three-layer structure polymer is an innermost hard layer polymer (a) 5 to 40% by mass, a soft layer polymer (b) 30 to 60% by mass, and An outermost hard layer polymer (c) comprising 20 to 50% by mass, having an insoluble part when fractionated with acetone, and an acrylic granular composite having a methyl ethyl ketone swelling degree of 1.5 to 4.0 at the insoluble part .
　なお、特公昭６０－１７４０６号あるいは特公平３－３９０９５号において開示されている様に、多層構造アクリル系粒状複合体の各層の組成や粒子径を規定しただけでなく、多層構造アクリル系粒状複合体の引張り弾性率やアセトン不溶部のメチルエチルケトン膨潤度を特定範囲内に設定することにより、さらに充分な耐衝撃性と耐応力白化性のバランスを実現することが可能となる。 As disclosed in Japanese Patent Publication No. 60-17406 or Japanese Patent Publication No. 3-39095, not only the composition and particle diameter of each layer of the multilayered acrylic granular composite are defined, but also the multilayered acrylic granular composite. By setting the tensile modulus of the body and the degree of swelling of methyl ethyl ketone in the acetone-insoluble part within a specific range, it is possible to realize a further sufficient balance between impact resistance and stress whitening resistance.
　ここで、多層構造アクリル系粒状複合体を構成する最内硬質層重合体（ａ）は、メチルメタクリレート８０～９８．９質量％、アルキル基の炭素数が１～８のアルキルアクリレート１～２０質量％および多官能性グラフト剤０．０１～０．３質量％からなる単量体混合物を重合して得られるものが好ましい。 Here, the innermost hard layer polymer (a) constituting the multilayer structure acrylic granular composite is 80 to 98.9% by mass of methyl methacrylate and 1 to 20 mass of alkyl acrylate having 1 to 8 carbon atoms in the alkyl group. % And a monomer mixture consisting of 0.01 to 0.3% by mass of a polyfunctional grafting agent is preferred.
　ここで、アルキル基の炭素数が１～８のアルキルアクリレートとしては、メチルアクリレート、エチルアクリレート、ｎ－プロピルアクリレート、ｎ－ブチルアクリレート、ｓ－ブチルアクリレート、２－エチルヘキシルアクリレート等が挙げられ、メチルアクリレートやｎ－ブチルアクリレートが好ましく用いられる。 Here, examples of the alkyl acrylate having 1 to 8 carbon atoms in the alkyl group include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, 2-ethylhexyl acrylate, and the like. And n-butyl acrylate are preferably used.
　最内硬質層重合体（ａ）におけるアルキルアクリレート単位の割合は１～２０質量％であり、該単位が１質量％未満では、重合体の熱分解性が大きくなり、一方、該単位が２０質量％を越えると、最内硬質層重合体（ｃ）のガラス転移温度が低くなり、３層構造アクリル系粒状複合体の耐衝撃性付与効果が低下するので、いずれも好ましくない。 The proportion of the alkyl acrylate unit in the innermost hard layer polymer (a) is 1 to 20% by mass. When the unit is less than 1% by mass, the thermal decomposability of the polymer is increased, while the unit is 20% by mass. If it exceeds 50%, the glass transition temperature of the innermost hard layer polymer (c) is lowered, and the impact resistance imparting effect of the three-layer structure acrylic granular composite is lowered.
　多官能性グラフト剤としては、異なる重合可能な官能基を有する多官能性単量体、例えば、アクリル酸、メタクリル酸、マレイン酸、フマル酸のアリルエステル等が挙げられ、アリルメタクリレートが好ましく用いられる。多官能性グラフト剤は、最内硬質層重合体と軟質層重合体を化学的に結合するために用いられ、その最内硬質層重合時に用いる割合は０．０１～０．３質量％である。 Examples of the polyfunctional grafting agent include polyfunctional monomers having different polymerizable functional groups, such as allyl esters of acrylic acid, methacrylic acid, maleic acid, and fumaric acid, and allyl methacrylate is preferably used. . The polyfunctional grafting agent is used to chemically bond the innermost hard layer polymer and the soft layer polymer, and the ratio used during the innermost hard layer polymerization is 0.01 to 0.3% by mass. .
　アクリル系粒状複合体を構成する架橋軟質層重合体（ｂ）は、上記最内硬質層重合体（ａ）の存在下に、アルキル基の炭素数が１～８のアルキルアクリレート７５～９８．５質量％、多官能性架橋剤０．０１～５質量％および多官能性グラフト剤０．５～５質量％からなる単量体混合物を重合して得られるものが好ましい。 The crosslinked soft layer polymer (b) constituting the acrylic granular composite is an alkyl acrylate having from 9 to 8 carbon atoms having an alkyl group of 1 to 8 in the presence of the innermost hard layer polymer (a). What is obtained by polymerizing a monomer mixture consisting of 10% by mass, 0.01 to 5% by mass of a multifunctional crosslinking agent and 0.5 to 5% by mass of a multifunctional grafting agent is preferred.
　ここで、アルキル基の炭素数が４～８のアルキルアクリレートとしては、ｎ－ブチルアクリレートや２－エチルヘキシルアクリレートが好ましく用いられる。 Here, n-butyl acrylate or 2-ethylhexyl acrylate is preferably used as the alkyl acrylate having 4 to 8 carbon atoms in the alkyl group.
　また、これらの重合性単量体と共に、２５質量％以下の共重合可能な他の単官能性単量体を共重合させることも可能である。 In addition to these polymerizable monomers, it is possible to copolymerize 25% by mass or less of other monofunctional monomers capable of copolymerization.
　共重合可能な他の単官能性単量体としては、スチレンおよび置換スチレン誘導体が挙げられる。アルキル基の炭素数が４～８のアルキルアクリレートとスチレンとの比率は、前者が多いほど生成重合体（ｂ）のガラス転移温度が低下し、即ち軟質化できるのである。 Examples of other monofunctional monomers that can be copolymerized include styrene and substituted styrene derivatives. As the ratio of the alkyl acrylate having 4 to 8 carbon atoms in the alkyl group and styrene increases, the glass transition temperature of the produced polymer (b) decreases as the former increases, that is, it can be softened.
　一方、樹脂組生物の透明性の観点からは、軟質層重合体（ｂ）の常温での屈折率を最内硬質層重合体（ａ）、最外硬質層重合体（ｃ）、および硬質熱可塑性アクリル樹脂に近づけるほうが有利であり、これらを勘案して両者の比率を選定する。 On the other hand, from the viewpoint of the transparency of the resin assembly, the refractive index of the soft layer polymer (b) at room temperature is set to the innermost hard layer polymer (a), the outermost hard layer polymer (c), and the hard heat. It is more advantageous to make it closer to the plastic acrylic resin, and the ratio between them is selected in consideration of these.
　例えば、被覆層厚みの小さな用途においては、必ずしもスチレンを共重合しなくとも良い。 For example, in applications where the coating layer thickness is small, it is not always necessary to copolymerize styrene.
　多官能性グラフト剤としては、前記の最内層硬質重合体（ａ）の項で挙げたものを用いることができる。ここで用いる多官能性グラフト剤は、軟質層重合体（ｂ）と最外硬質層重合体（ｃ）を化学的に結合するために用いられ、その最内硬質層重合時に用いる割合は耐衝撃性付与効果の観点から０．５～５質量％が好ましい。 As the polyfunctional grafting agent, those mentioned in the section of the innermost layer hard polymer (a) can be used. The polyfunctional grafting agent used here is used to chemically bond the soft layer polymer (b) and the outermost hard layer polymer (c), and the proportion used during the innermost hard layer polymerization is impact resistance. From the viewpoint of the effect of imparting properties, 0.5 to 5% by mass is preferable.
　多官能性架橋剤としては、ジビニル化合物、ジアリル化合物、ジアクリル化合物、ジメタクリル化合物などの一般に知られている架橋剤が使用できるが、ポリエチレングリコールジアクリレート（分子量２００～６００）が好ましく用いられる。 As the polyfunctional crosslinking agent, generally known crosslinking agents such as divinyl compounds, diallyl compounds, diacrylic compounds, dimethacrylic compounds and the like can be used, but polyethylene glycol diacrylate (molecular weight 200 to 600) is preferably used.
　ここで用いる多官能性架橋剤は、軟質層（ｂ）の重合時に架橋構造を生成し、耐衝撃性付与の効果を発現させるために用いられる。ただし、先の多官能性グラフト剤を軟質層の重合時に用いれば、ある程度は軟質層（ｂ）の架橋構造を生成するので、多官能性架橋剤は必須成分ではないが、多官能性架橋剤を軟質層重合時に用いる割合は耐衝撃性付与効果の観点から０．０１～５質量％が好ましい。 The polyfunctional cross-linking agent used here is used to generate a cross-linked structure during the polymerization of the soft layer (b) and to exhibit the effect of imparting impact resistance. However, if the above-mentioned polyfunctional grafting agent is used during the polymerization of the soft layer, the polyfunctional crosslinking agent is not an essential component because the crosslinked structure of the soft layer (b) is generated to some extent. Is preferably 0.01 to 5% by weight from the viewpoint of imparting impact resistance.
　多層構造アクリル系粒状複合体を構成する最外硬質層重合体（ｃ）は、上記最内硬質層重合体（ａ）および軟質層重合体（ｂ）の存在下に、メチルメタクリレート８０～９９質量％およびアルキル基の炭素数が１～８であるアルキルアクリレート１～２０質量％からなる単量体混合物を重合して得られるものが好ましい。 The outermost hard layer polymer (c) constituting the multi-layer structure acrylic granular composite has a methyl methacrylate of 80 to 99 mass in the presence of the innermost hard layer polymer (a) and the soft layer polymer (b). % And a monomer mixture comprising 1 to 20% by mass of an alkyl acrylate having 1 to 8 carbon atoms in the alkyl group is preferred.
　ここで、アクリルアルキレートとしては、前述したものが用いられるが、メチルアクリレートやエチルアクリレートが好ましく用いられる。最外硬質層（ｃ）におけるアルキルアクリレート単位の割合は、１～２０質量％が好ましい。 Here, as the acrylic alkylate, those described above are used, but methyl acrylate and ethyl acrylate are preferably used. The proportion of the alkyl acrylate unit in the outermost hard layer (c) is preferably 1 to 20% by mass.
　また、最外硬質層（ｃ）の重合時に、アクリル樹脂（Ａ）との相溶性向上を目的として、分子量を調節するためアルキルメルカプタン等を連鎖移動剤として用い、実施することも可能である。 Also, when the outermost hard layer (c) is polymerized, an alkyl mercaptan or the like can be used as a chain transfer agent to adjust the molecular weight for the purpose of improving the compatibility with the acrylic resin (A).
　とりわけ、最外硬質層に、分子量が内側から外側へ向かって次第に小さくなるような勾配を設けることは、伸びと耐衝撃性のバランスを改良するうえで好ましい。具体的な方法としては、最外硬質層を形成するための単量体混合物を２つ以上に分割し、各回ごとに添加する連鎖移動剤量を順次増加するような手法によって、分子量を内側から外側へ向かって小さくすることが可能である。 In particular, it is preferable to provide the outermost hard layer with a gradient such that the molecular weight gradually decreases from the inside toward the outside in order to improve the balance between elongation and impact resistance. As a specific method, the monomer mixture for forming the outermost hard layer is divided into two or more, and the molecular weight is increased from the inside by a method of sequentially increasing the amount of chain transfer agent added each time. It is possible to make it smaller toward the outside.
　この際に形成される分子量は、各回に用いられる単量体混合物をそれ単独で同条件にて重合し、得られた重合体の分子量を測定することによって調べることもできる。 The molecular weight formed at this time can also be examined by polymerizing the monomer mixture used each time under the same conditions, and measuring the molecular weight of the obtained polymer.
　本発明に好ましく用いられる多層構造重合体であるアクリル系粒状複合体の粒子径については、特に限定されるものではないが、１０ｎｍ以上、１０００ｎｍ以下であることが好ましく、さらに、２０ｎｍ以上、５００ｎｍ以下であることがより好ましく、特に５０ｎｍ以上、４００ｎｍ以下であることが最も好ましい。 The particle diameter of the acrylic granular composite which is a multilayer structure polymer preferably used in the present invention is not particularly limited, but is preferably 10 nm or more and 1000 nm or less, and more preferably 20 nm or more and 500 nm or less. More preferably, it is most preferably 50 nm or more and 400 nm or less.
　本発明に好ましく用いられる多層構造重合体であるアクリル系粒状複合体において、コアとシェルの質量比は、特に限定されるものではないが、多層構造重合体全体を１００質量部としたときに、コア層が５０質量部以上、９０質量部以下であることが好ましく、さらに、６０質量部以上、８０質量部以下であることがより好ましい。 In the acrylic granular composite that is a multilayer structure polymer preferably used in the present invention, the mass ratio of the core and the shell is not particularly limited, but when the entire multilayer structure polymer is 100 parts by mass, The core layer is preferably 50 parts by mass or more and 90 parts by mass or less, and more preferably 60 parts by mass or more and 80 parts by mass or less.
　このような多層構造アクリル系粒状複合体の市販品の例としては、例えば、三菱レイヨン社製“メタブレン”、鐘淵化学工業社製“カネエース”、呉羽化学工業社製“パラロイド”、ロームアンドハース社製“アクリロイド”、ガンツ化成工業社製“スタフィロイド”およびクラレ社製“パラペットＳＡ”などが挙げられ、これらは、単独ないし２種以上を用いることができる。 Examples of such commercially available multilayered acrylic granular composites include, for example, “Metablene” manufactured by Mitsubishi Rayon Co., “Kane Ace” manufactured by Kaneka Chemical Co., Ltd., “Paraloid” manufactured by Kureha Chemical Co., Ltd., Rohm and Haas “Acryloid” manufactured by KK, “Staffyroid” manufactured by Ganz Kasei Kogyo Co., Ltd., “Parapet SA” manufactured by Kuraray Co., Ltd., and the like can be used alone or in combination of two or more.
　また、本発明に好ましく用いられるアクリル粒子として好適に使用されるグラフト共重合体であるアクリル粒子の具体例としては、ゴム質重合体の存在下に、不飽和カルボン酸エステル系単量体、不飽和カルボン酸系単量体、芳香族ビニル系単量体、および必要に応じてこれらと共重合可能な他のビニル系単量体からなる単量体混合物を共重合せしめたグラフト共重合体が挙げられる。 In addition, specific examples of the acrylic particles that are graft copolymers that are preferably used as the acrylic particles preferably used in the present invention include unsaturated carboxylic acid ester monomers, unsaturated monomers in the presence of a rubbery polymer. A graft copolymer obtained by copolymerizing a monomer mixture comprising a saturated carboxylic acid monomer, an aromatic vinyl monomer, and, if necessary, other vinyl monomers copolymerizable therewith. Can be mentioned.
　グラフト共重合体であるアクリル粒子に用いられるゴム質重合体には特に制限はないが、ジエン系ゴム、アクリル系ゴムおよびエチレン系ゴムなどが使用できる。具体例としては、ポリブタジエン、スチレン－ブタジエン共重合体、スチレン－ブタジエンのブロック共重合体、アクリロニトリル－ブタジエン共重合体、アクリル酸ブチル－ブタジエン共重合体、ポリイソプレン、ブタジエン－メタクリル酸メチル共重合体、アクリル酸ブチル－メタクリル酸メチル共重合体、ブタジエン－アクリル酸エチル共重合体、エチレン－プロピレン共重合体、エチレン－プロピレン－ジエン系共重合体、エチレン－イソプレン共重合体、およびエチレン－アクリル酸メチル共重合体などが挙げられる。これらのゴム質重合体は、１種または２種以上の混合物で使用することが可能である。 There is no particular limitation on the rubbery polymer used for the acrylic particles that are the graft copolymer, but diene rubber, acrylic rubber, ethylene rubber, and the like can be used. Specific examples include polybutadiene, styrene-butadiene copolymer, block copolymer of styrene-butadiene, acrylonitrile-butadiene copolymer, butyl acrylate-butadiene copolymer, polyisoprene, butadiene-methyl methacrylate copolymer. , Butyl acrylate-methyl methacrylate copolymer, butadiene-ethyl acrylate copolymer, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, ethylene-isoprene copolymer, and ethylene-acrylic acid Examples thereof include a methyl copolymer. These rubbery polymers can be used alone or in a mixture of two or more.
　また、アクリル樹脂（Ａ）およびアクリル粒子のそれぞれの屈折率が近似している場合、本発明に係るアクリル樹脂含有フィルムの透明性を得ることができるため、好ましい。具体的には、アクリル粒子とアクリル樹脂（Ａ）の屈折率差が０．０５以下であることが好ましく、より好ましくは０．０２以下、とりわけ０．０１以下であることが好ましい。 Further, it is preferable that the refractive indexes of the acrylic resin (A) and the acrylic particles are approximate because the transparency of the acrylic resin-containing film according to the present invention can be obtained. Specifically, the refractive index difference between the acrylic particles and the acrylic resin (A) is preferably 0.05 or less, more preferably 0.02 or less, and particularly preferably 0.01 or less.
　このような屈折率条件を満たすためには、アクリル樹脂（Ａ）の各単量体単位組成比を調整する方法、および／またはアクリル粒子に使用されるゴム質重合体あるいは単量体の組成比を調製する方法などにより、屈折率差を小さくすることができ、透明性に優れたアクリル樹脂含有フィルムを得ることができる。 In order to satisfy such a refractive index condition, a method of adjusting the monomer unit composition ratio of the acrylic resin (A) and / or the composition ratio of the rubbery polymer or monomer used in the acrylic particles The difference in refractive index can be reduced by the method of preparing the film, and an acrylic resin-containing film excellent in transparency can be obtained.
　尚、ここで言う屈折率差とは、アクリル樹脂（Ａ）が可溶な溶媒に、本発明に係るアクリル樹脂含有フィルムを適当な条件で十分に溶解させ白濁溶液とし、これを遠心分離等の操作により、溶媒可溶部分と不溶部分に分離し、この可溶部分（アクリル樹脂（Ａ））と不溶部分（アクリル粒子）をそれぞれ精製した後、測定した屈折率（２３℃、測定波長：５５０ｎｍ）の差を示す。 The difference in refractive index referred to here means that the acrylic resin-containing film according to the present invention is sufficiently dissolved in a solvent in which the acrylic resin (A) is soluble to obtain a cloudy solution, which is centrifuged. The solvent was separated into a solvent-soluble part and an insoluble part by the operation, and the soluble part (acrylic resin (A)) and the insoluble part (acrylic particles) were purified, and then the measured refractive index (23 ° C., measurement wavelength: 550 nm). ) Difference.
　本発明においてアクリル樹脂（Ａ）に、アクリル粒子を配合する方法には、特に制限はなく、アクリル樹脂（Ａ）とその他の任意成分を予めブレンドした後、通常２００～３５０℃において、アクリル粒子を添加しながら一軸または二軸押出機により均一に溶融混練する方法が好ましく用いられる。 In the present invention, the method of blending the acrylic particles with the acrylic resin (A) is not particularly limited, and after the acrylic resin (A) and other optional components are previously blended, the acrylic particles are usually added at 200 to 350 ° C. A method of uniformly melting and kneading with a single or twin screw extruder while adding is preferably used.
　また、アクリル粒子を予め分散した溶液を、アクリル樹脂（Ａ）、及びセルロースエステル樹脂（Ｂ）を溶解した溶液（ドープ液）に添加して混合する方法や、アクリル粒子及びその他の任意の添加剤を溶解、混合した溶液をインライン添加する等の方法を用いることができる。 Further, a method in which a solution in which acrylic particles are dispersed in advance is added to and mixed with a solution (dope solution) in which acrylic resin (A) and cellulose ester resin (B) are dissolved, acrylic particles and other optional additives. A method such as in-line addition of a solution obtained by dissolving and mixing the above can be used.
　本発明に係るアクリル粒子としては、市販のものも使用することができる。例えば、メタブレンＷ－３４１（三菱レイヨン（株）製）を、ケミスノーＭＲ－２Ｇ、ＭＳ－３００Ｘ（綜研化学（株）製）等を挙げることができる。 Commercially available acrylic particles can also be used as the acrylic particles according to the present invention. For example, Metabrene W-341 (manufactured by Mitsubishi Rayon Co., Ltd.), Chemisnow MR-2G, MS-300X (manufactured by Soken Chemical Co., Ltd.) and the like can be mentioned.
　本発明のアクリル樹脂含有フィルムにおいて、該フィルムを構成する樹脂の総質量に対して、０．５～４５質量％のアクリル粒子を含有することが好ましい。 The acrylic resin-containing film of the present invention preferably contains 0.5 to 45% by mass of acrylic particles with respect to the total mass of the resin constituting the film.
　〈可塑剤〉
　本発明に係るフィルムの製造においては、フィルム形成材料中に可塑剤を含有させても良い。 <Plasticizer>
In the production of the film according to the present invention, a plasticizer may be contained in the film forming material.
　用いることのできる可塑剤としては、特に限定されないが、例えば、多価アルコールエステル系可塑剤、ポリエステル系可塑剤、３価以上の芳香族多価カルボン酸エステル系可塑剤、グリコレート系可塑剤、リン酸エステル系可塑剤、フタル酸エステル系可塑剤、脂肪酸エステル系可塑剤、糖エステル系化合物、アクリル系ポリマーなどを用いることができる。特に好ましくは、多価アルコール系可塑剤である。また、リン酸エステル系可塑剤の添加量は偏光度の耐久性の観点から６質量％以下とすることが好ましい。 The plasticizer that can be used is not particularly limited. For example, a polyhydric alcohol ester plasticizer, a polyester plasticizer, a trivalent or higher aromatic polycarboxylic acid ester plasticizer, a glycolate plasticizer, Phosphate ester plasticizers, phthalate ester plasticizers, fatty acid ester plasticizers, sugar ester compounds, acrylic polymers, and the like can be used. Particularly preferred are polyhydric alcohol plasticizers. Moreover, it is preferable that the addition amount of a phosphoric ester plasticizer shall be 6 mass% or less from a durable viewpoint of a polarization degree.
　可塑剤は１％減量温度（Ｔｄ１）が２５０℃以上であることが好ましく、より好ましくは２８０℃以上であり、特に好ましくは３００℃以上である。 The plasticizer preferably has a 1% weight loss temperature (Td1) of 250 ° C. or higher, more preferably 280 ° C. or higher, and particularly preferably 300 ° C. or higher.
　多価アルコールエステルは、２価以上の脂肪族多価アルコールとモノカルボン酸のエステルよりなり、分子内に芳香環またはシクロアルキル環を有することが好ましい。 The polyhydric alcohol ester is composed of an ester of a dihydric or higher aliphatic polyhydric alcohol and a monocarboxylic acid, and preferably has an aromatic ring or a cycloalkyl ring in the molecule.
　多価アルコールエステルに用いられる多価アルコールは、次の一般式（１）で表される。 The polyhydric alcohol used in the polyhydric alcohol ester is represented by the following general formula (1).
　一般式（１）：Ｒ１－（ＯＨ）ｎ
　式中、Ｒ１はｎ価の有機基、ｎは２以上の正の整数、ＯＨ基はアルコール性水酸基またはフェノール性水酸基を表す。 General formula (1): R 1- (OH) n
In the formula, R 1 represents an n-valent organic group, n represents a positive integer of 2 or more, and the OH group represents an alcoholic hydroxyl group or a phenolic hydroxyl group.
　好ましい多価アルコールの例としては、以下のようなものを挙げることができるが、本発明はこれらに限定されるものではない。 Examples of preferable polyhydric alcohols include the following, but the present invention is not limited to these.
　アドニトール、アラビトール、エチレングリコール、ジエチレングリコール、トリエチレングリコール、テトラエチレングリコール、１，２－プロパンジオール、１，３－プロパンジオール、ジプロピレングリコール、トリプロピレングリコール、１，２－ブタンジオール、１，３－ブタンジオール、１，４－ブタンジオール、ジブチレングリコール、１，２，４－ブタントリオール、１，５－ペンタンジオール、１，６－ヘキサンジオール、１，２，３－ヘキサントリオール、１，２，６－ヘキサントリオール、グリセリン、ジグリセリン、ガラクチトール、イノシトール、マンニトール、３－メチルペンタン－１，３，５－トリオール、ピナコール、ソルビトール、トリメチロールプロパン、トリメチロールエタン、ペンタエリスリトール、ジペンタエリスリトール、キシリトールなどを挙げることができる。中でもグリセリン、トリメチロールエタン、トリメチロールプロパン、ペンタエリスリトールが好ましい。 Adonitol, arabitol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3- Butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 1,6-hexanediol, 1,2,3-hexanetriol, 1,2, 6-hexanetriol, glycerin, diglycerin, galactitol, inositol, mannitol, 3-methylpentane-1,3,5-triol, pinacol, sorbitol, trimethylolpropane, trimethylolethane, pentaerythritol It can be mentioned Lumpur, dipentaerythritol, xylitol and the like. Of these, glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol are preferable.
　本発明に係る多価アルコールエステルに用いられるモノカルボン酸としては、特に制限はなく、公知の脂肪族モノカルボン酸、脂環族モノカルボン酸、芳香族モノカルボン酸などを用いることができる。脂環族モノカルボン酸、芳香族モノカルボン酸を用いると、透湿性、保留性を向上させる点で好ましい。好ましいモノカルボン酸の例としては、以下のようなものを挙げることができるが、本発明はこれに限定されるものではない。 The monocarboxylic acid used in the polyhydric alcohol ester according to the present invention is not particularly limited, and known aliphatic monocarboxylic acid, alicyclic monocarboxylic acid, aromatic monocarboxylic acid and the like can be used. Use of an alicyclic monocarboxylic acid or aromatic monocarboxylic acid is preferable in terms of improving moisture permeability and retention. Examples of preferred monocarboxylic acids include the following, but the present invention is not limited thereto.
　脂肪族モノカルボン酸としては、炭素数１～３２の直鎖または側鎖を持った脂肪酸を好ましく用いることができる。炭素数１～２０であることがさらに好ましく、炭素数１～１０であることが特に好ましい。酢酸を用いるとセルロースエステルとの相溶性が増すため好ましく、酢酸と他のモノカルボン酸を混合して用いることも好ましい。 As the aliphatic monocarboxylic acid, a fatty acid having a straight chain or a side chain having 1 to 32 carbon atoms can be preferably used. More preferably, it has 1 to 20 carbon atoms, and particularly preferably 1 to 10 carbon atoms. The use of acetic acid is preferred because the compatibility with the cellulose ester is increased, and it is also preferred to use a mixture of acetic acid and another monocarboxylic acid.
　好ましい脂肪族モノカルボン酸としては、酢酸、プロピオン酸、酪酸、吉草酸、カプロン酸、エナント酸、カプリル酸、ペラルゴン酸、カプリン酸、２－エチル－ヘキサンカルボン酸、ウンデシル酸、ラウリン酸、トリデシル酸、ミリスチン酸、ペンタデシル酸、パルミチン酸、ヘプタデシル酸、ステアリン酸、ノナデカン酸、アラキン酸、ベヘン酸、リグノセリン酸、セロチン酸、ヘプタコサン酸、モンタン酸、メリシン酸、ラクセル酸などの飽和脂肪酸、ウンデシレン酸、オレイン酸、ソルビン酸、リノール酸、リノレン酸、アラキドン酸などの不飽和脂肪酸などを挙げることができる。 Preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecylic acid, lauric acid, tridecylic acid , Saturated fatty acids such as myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, heptacosanoic acid, montanic acid, melicic acid, laccelic acid, undecylenic acid, Examples thereof include unsaturated fatty acids such as oleic acid, sorbic acid, linoleic acid, linolenic acid and arachidonic acid.
　好ましい脂環族モノカルボン酸としては炭素数３～８のシクロアルキル基が好ましく、具体的にはシクロペンタンカルボン酸、シクロヘキサンカルボン酸、シクロオクタンカルボン酸などが挙げられる。 Preferred alicyclic monocarboxylic acids are preferably cycloalkyl groups having 3 to 8 carbon atoms, and specific examples include cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, and cyclooctanecarboxylic acid.
　好ましい芳香族モノカルボン酸の例としては、安息香酸、トルイル酸などの安息香酸のベンゼン環にアルキル基を導入したもの、ビフェニルカルボン酸、ナフタリンカルボン酸、テトラリンカルボン酸などのベンゼン環を２個以上持つ芳香族モノカルボン酸を挙げることができる。特に、安息香酸が好ましい。 Examples of preferred aromatic monocarboxylic acids include those in which an alkyl group is introduced into the benzene ring of benzoic acid such as benzoic acid and toluic acid, and two or more benzene rings such as biphenyl carboxylic acid, naphthalene carboxylic acid, and tetralin carboxylic acid. An aromatic monocarboxylic acid possessed can be mentioned. In particular, benzoic acid is preferred.
　これらの脂環族モノカルボン酸および芳香族モノカルボン酸は置換されていてもよく、好ましい置換基としては、ハロゲン原子、例えば、塩素原子、臭素原子、フッ素原子等、ヒドロキシル基、アルキル基、アルコキシ基、シクロアルコキシ基、アラルキル基（このフェニル基にはアルキル基またはハロゲン原子等によってさらに置換されていてもよい）、ビニル基、アリル基等のアルケニル基、フェニル基（このフェニル基にはアルキル基またはハロゲン原子等によってさらに置換されていてもよい。）、フェノキシ基（このフェニル基にはアルキル基またはハロゲン原子等によってさらに置換されていてもよい。）、アセチル基、プロピオニル基等の炭素数２～８のアシル基、またアセチルオキシ基、プロピオニルオキシ基等の炭素数２～８の無置換のカルボニルオキシ基等が挙げられる。 These alicyclic monocarboxylic acids and aromatic monocarboxylic acids may be substituted, and preferred substituents include halogen atoms such as chlorine atom, bromine atom, fluorine atom, hydroxyl group, alkyl group, alkoxy group. Group, cycloalkoxy group, aralkyl group (this phenyl group may be further substituted with an alkyl group or a halogen atom), alkenyl groups such as vinyl group, allyl group, phenyl group (this phenyl group has an alkyl group) Or a phenoxy group (this phenyl group may be further substituted with an alkyl group or a halogen atom), an acetyl group, a propionyl group, or the like. Carbon number such as ˜8 acyl group, acetyloxy group, propionyloxy group Etc. unsubstituted carbonyl group having 1-8 thereof.
　多価アルコールエステルの分子量は特に制限はないが、揮発性、相溶性等の観点から、分子量３００～１５００の範囲であることが好ましく、４００～１０００の範囲であることがさらに好ましい。 The molecular weight of the polyhydric alcohol ester is not particularly limited, but from the viewpoint of volatility, compatibility and the like, the molecular weight is preferably in the range of 300 to 1500, and more preferably in the range of 400 to 1000.
　多価アルコールエステルに用いられるモノカルボン酸は一種類でもよいし、二種以上の混合であってもよい。また、多価アルコール中のＯＨ基は全てエステル化してもよいし、一部をＯＨ基のままで残してもよい。 The monocarboxylic acid used in the polyhydric alcohol ester may be one kind or a mixture of two or more kinds. Moreover, all the OH groups in the polyhydric alcohol may be esterified, or a part of the OH groups may be left as they are.
　多価アルコールエステルは、公知の方法により合成できる。前記モノカルボン酸と、前記多価アルコールを例えば、酸の存在下縮合させエステル化する方法、また、有機酸を予め酸クロライドあるいは酸無水物としておき、多価アルコールと反応させる方法、有機酸のフェニルエステルと多価アルコールを反応させる方法等があり、目的とするエステル化合物により、適宜、収率のよい方法を選択することが好ましい。 The polyhydric alcohol ester can be synthesized by a known method. For example, a method of condensing and esterifying the monocarboxylic acid and the polyhydric alcohol in the presence of an acid, a method of previously reacting an organic acid with an acid chloride or acid anhydride and reacting with the polyhydric alcohol, There is a method of reacting a phenyl ester and a polyhydric alcohol, and it is preferable to select a method with a good yield appropriately depending on the target ester compound.
　可塑剤としての多価アルコールエステルは、前記多価アルコール脂肪酸エステルを兼ねても良い。 The polyhydric alcohol ester as a plasticizer may also serve as the polyhydric alcohol fatty acid ester.
　ポリエステル系可塑剤としては、分子内に芳香環またはシクロアルキル環を有するポリエステル系可塑剤を用いることが好ましい。好ましいポリエステル系可塑剤としては、特に限定されないが、例えば、下記一般式（ｉ）で表させる。 As the polyester plasticizer, it is preferable to use a polyester plasticizer having an aromatic ring or a cycloalkyl ring in the molecule. Although it does not specifically limit as a preferable polyester plasticizer, For example, it represents with the following general formula (i).
　一般式（ｉ）：Ｂ－（Ｇ－Ａ）ｎ１－Ｇ－Ｂ
（式中、Ｂはベンゼンモノカルボン酸残基、Ｇは炭素数２～１２のアルキレングリコール残基または炭素数６～１２のアリールグリコール残基または炭素数が４～１２のオキシアルキレングリコール残基、Ａは炭素数２～１２のアルキレンジカルボン酸残基または炭素数６～１２のアリールジカルボン酸残基を表し、またｎ１は１以上の整数を表す。）
　一般式（ｉ）中、Ｂで示されるベンゼンモノカルボン酸残基とＧで示されるアルキレングリコール残基またはオキシアルキレングリコール残基またはアリールグリコール残基、Ａで示されるアルキレンジカルボン酸残基またはアリールジカルボン酸残基とから構成されるものであり、通常のポリエステル系可塑剤と同様の反応により得られる。 Formula (i): B- (GA) n1 -GB
(Wherein B is a benzene monocarboxylic acid residue, G is an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or an oxyalkylene glycol residue having 4 to 12 carbon atoms, A represents an alkylene dicarboxylic acid residue having 2 to 12 carbon atoms or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n1 represents an integer of 1 or more.)
In the general formula (i), a benzene monocarboxylic acid residue represented by B and an alkylene glycol residue, oxyalkylene glycol residue or aryl glycol residue represented by G, an alkylene dicarboxylic acid residue or aryl dicarboxylic group represented by A It is composed of an acid residue and can be obtained by a reaction similar to that of a normal polyester plasticizer.
　本発明で使用されるポリエステル系可塑剤のベンゼンモノカルボン酸成分としては、例えば、安息香酸、パラターシャリブチル安息香酸、オルソトルイル酸、メタトルイル酸、パラトルイル酸、ジメチル安息香酸、エチル安息香酸、ノルマルプロピル安息香酸、アミノ安息香酸、アセトキシ安息香酸等があり、これらはそれぞれ一種または二種以上の混合物として使用することができる。 Examples of the benzene monocarboxylic acid component of the polyester plasticizer used in the present invention include benzoic acid, para-tert-butylbenzoic acid, orthotoluic acid, metatoluic acid, p-toluic acid, dimethylbenzoic acid, ethylbenzoic acid, and normalpropyl. There are benzoic acid, aminobenzoic acid, acetoxybenzoic acid and the like, and these can be used as one kind or a mixture of two or more kinds, respectively.
　ポリエステル系可塑剤の炭素数２～１２のアルキレングリコール成分としては、エチレングリコール、１，２－プロピレングリコール、１，３－プロピレングリコール、１，２－ブタンジオール、１，３－ブタンジオール、２－メチル１，３－プロパンジオール、１，４－ブタンジオール、１，５－ペンタンジオール、２，２－ジメチル－１，３－プロパンジオール（ネオペンチルグリコール）、２，２－ジエチル－１，３－プロパンジオール（３，３－ジメチロ－ルペンタン）、２－ｎ－ブチル－２－エチル－１，３プロパンジオール（３，３－ジメチロールヘプタン）、３－メチル－１，５－ペンタンジオール１，６－ヘキサンジオール、２，２，４－トリメチル１，３－ペンタンジオール、２－エチル１，３－ヘキサンジオール、２－メチル１，８－オクタンジオール、１，９－ノナンジオール、１，１０－デカンジオール、１，１２－オクタデカンジオール等があり、これらのグリコールは、一種または二種以上の混合物として使用される。 Examples of the alkylene glycol component having 2 to 12 carbon atoms of the polyester plasticizer include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 2- Methyl 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2,2-diethyl-1,3- Propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3propanediol (3,3-dimethylolheptane), 3-methyl-1,5-pentanediol 1,6 -Hexanediol, 2,2,4-trimethyl 1,3-pentanediol, 2-ethyl 1,3-hexanediol, 2 Methyl 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, there are 1,12-octadecane diol, these glycols may be used as alone or in combination of two or more.
　また、芳香族末端エステルの炭素数４～１２のオキシアルキレングリコール成分としては、例えば、ジエチレングリコール、トリエチレングリコール、テトラエチレングリコール、ジプロピレングリコール、トリプロピレングリコール等があり、これらのグリコールは、１種または２種以上の混合物として使用できる。 Examples of the oxyalkylene glycol component having 4 to 12 carbon atoms of the aromatic terminal ester include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, and the like. Or it can be used as a mixture of two or more.
　芳香族末端エステルの炭素数４～１２のアルキレンジカルボン酸成分としては、例えば、コハク酸、マレイン酸、フマル酸、グルタル酸、アジピン酸、アゼライン酸、セバシン酸、ドデカンジカルボン酸等があり、これらは、それぞれ一種または二種以上の混合物として使用される。炭素数６～１２のアリーレンジカルボン酸成分としては、フタル酸、イソフタル酸、テレフタル酸、１，５－ナフタレンジカルボン酸、１，４－ナフタレンジカルボン酸等がある。 Examples of the alkylene dicarboxylic acid component having 4 to 12 carbon atoms of the aromatic terminal ester include succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, and dodecanedicarboxylic acid. These are used as one kind or a mixture of two or more kinds. Examples of the arylene dicarboxylic acid component having 6 to 12 carbon atoms include phthalic acid, isophthalic acid, terephthalic acid, 1,5-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, and the like.
　本発明で使用されるポリエステル系可塑剤は数平均分子量が４００～２０００であることが好ましく、より好ましくは５００～１５００である。また、その酸価は０．５ｍｇＫＯＨ／ｇ以下、かつ水酸基価は２５ｍｇＫＯＨ／ｇ以下であることが好ましく、より好ましくは酸価０．３ｍｇＫＯＨ／ｇ以下、かつ水酸基価は１５ｍｇＫＯＨ／ｇ以下のものが好適である。 The polyester plasticizer used in the present invention preferably has a number average molecular weight of 400 to 2000, more preferably 500 to 1500. The acid value is preferably 0.5 mgKOH / g or less, and the hydroxyl value is preferably 25 mgKOH / g or less, more preferably the acid value is 0.3 mgKOH / g or less, and the hydroxyl value is 15 mgKOH / g or less. Is preferred.
　３価以上の芳香族多価カルボン酸エステル系可塑剤としてはトリメシン酸エステル、トリメリット酸エステルまたはピロメリット酸エステルであることが好ましい。芳香族多価カルボン酸とエステルを形成するアルコールは炭素数１～８のアルコールであることが好ましい。 The trivalent or higher aromatic polyvalent carboxylic acid ester plasticizer is preferably trimesic acid ester, trimellitic acid ester or pyromellitic acid ester. The alcohol that forms an ester with an aromatic polycarboxylic acid is preferably an alcohol having 1 to 8 carbon atoms.
　特に好ましい３価以上の芳香族多価カルボン酸エステル系可塑剤の例としては、トリメシン酸トリブチル、トリメシン酸トリヘキシル、トリメシン酸トリ２－エチル－ヘキシル、トリメシン酸トリシクロヘキシル、トリメリット酸トリブチル、トリメリット酸トリヘキシル、トリメリット酸トリ２－エチル－ヘキシル、トリメリット酸トリシクロヘキシル、ピロメリット酸テトラブチル、ピロメリット酸テトラヘキシル、ピロメリット酸テトラ２－エチルヘキシル、ピロメリット酸テトラシクロヘキシル、などが上げられるが本発明はこれらに限定されるものではない。 Examples of particularly preferred trivalent or higher aromatic polycarboxylic acid ester plasticizers include tributyl trimesate, trihexyl trimesate, tri-2-ethyl-hexyl trimesate, tricyclohexyl trimesate, tributyl trimellitic acid, trimellitate Trihexyl acid, tri-2-ethyl-hexyl trimellitic acid, tricyclohexyl trimellitic acid, tetrabutyl pyromellitic acid, tetrahexyl pyromellitic acid, tetra-2-ethylhexyl pyromellitic acid, tetracyclohexyl pyromellitic acid, etc. The invention is not limited to these examples.
　グリコレート系可塑剤としては、エチルフタリルエチルグリコレート、ブチルフタリルブチルグリコレート、リン酸エステル系可塑剤では、トリフェニルホスフェート、トリクレジルホスフェート、クレジルジフェニルホスフェート、オクチルジフェニルホスフェート、ジフェニルビフェニルホスフェート、トリオクチルホスフェート、トリブチルホスフェート、１，３－フェニレンビス（ジキシレニルホスフェート）、１，３－フェニレンビス（ジフェニルホスフェート）等、フタル酸エステル系可塑剤では、ジエチルフタレート、ジメトキシエチルフタレート、ジメチルフタレート、ジオクチルフタレート、ジブチルフタレート、ブチルベンジルフタレート、ジ－２－エチルヘキシルフタレート等を用いることができる。この他、アセチルトリブチルシトレートなどのクエン酸エステル系可塑剤、エポキシ化オイル系可塑剤なども使用することができる。 As glycolate plasticizers, ethyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, and phosphate ester plasticizers are triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl. For phthalate plasticizers such as phosphate, trioctyl phosphate, tributyl phosphate, 1,3-phenylene bis (dixylenyl phosphate), 1,3-phenylene bis (diphenyl phosphate), diethyl phthalate, dimethoxyethyl phthalate, dimethyl Phthalate, dioctyl phthalate, dibutyl phthalate, butyl benzyl phthalate, di-2-ethylhexyl phthalate and the like can be used. In addition, citrate plasticizers such as acetyltributyl citrate, epoxidized oil plasticizers, and the like can also be used.
　《酸化防止剤、熱劣化防止剤》
　本発明では、酸化防止剤、熱劣化防止剤としては、通常知られている劣化防止剤（酸化防止剤、過酸化物分解剤、ラジカル禁止剤、金属不活性化剤、酸捕獲剤、アミンなど）を使用することができる。特に、ラクトン系、イオウ系、フェノール系、二重結合系、ヒンダードアミン系、リン系化合物のものを好ましく用いることができる。劣化防止剤については、特開平３－１９９２０１号公報、特開平５－１９４７８９号公報、特開平５－２７１４７１号公報、特開平６－１０７８５４号公報に記載がある。 << Antioxidant, Heat degradation inhibitor >>
In the present invention, as an antioxidant and a thermal degradation inhibitor, generally known degradation inhibitors (antioxidants, peroxide decomposition agents, radical inhibitors, metal deactivators, acid scavengers, amines, etc.) ) Can be used. In particular, lactone, sulfur, phenol, double bond, hindered amine, and phosphorus compounds can be preferably used. The deterioration preventing agents are described in JP-A-3-199201, JP-A-5-194789, JP-A-5-271471, and JP-A-6-107854.
　上記フェノール系化合物としては、２，６－ジアルキルフェノール構造を有するものが好ましく、例えば、チバ・ジャパン（株）から、Ｉｒｇａｎｏｘ１０７６、Ｉｒｇａｎｏｘ１０１０という商品名で市販されているものが好ましい。 As the phenolic compound, those having a 2,6-dialkylphenol structure are preferable, for example, those commercially available from Ciba Japan Co., Ltd. under the trade names Irganox 1076 and Irganox 1010.
　上記リン系化合物は、例えば、住友化学（株）から、Ｓｕｍｉｌｉｚｅｒ－ＧＰ、ＡＤＥＫＡ（株）からＡＤＫ　ＳＴＡＢ　ＰＥＰ－２４Ｇ、ＡＤＫ　ＳＴＡＢ　ＰＥＰ－３６およびＡＤＫ　ＳＴＡＢ　３０１０、チバ・ジャパン（株）からＩＲＧＡＦＯＳ　Ｐ－ＥＰＱ、堺化学（株）からＧＳＹ－Ｐ１０１という商品名で市販されているものが好ましい。 The phosphorous compounds are, for example, Sumitomo Chemical Co., Ltd., Sumilizer-GP, ADEKA Co., Ltd., ADK STAB PEP-24G, ADK STAB PEP-36 and ADK STAB 3010, Ciba Japan Co., Ltd., IRGAFOS P- EPQ, commercially available from Sakai Chemical Co., Ltd. under the trade name GSY-P101 is preferred.
　上記ヒンダードアミン系化合物は、例えば、チバ・ジャパン（株）から、Ｔｉｎｕｖｉｎ１４４およびＴｉｎｕｖｉｎ７７０、ＡＤＥＫＡ（株）からＡＤＫ　ＳＴＡＢ　ＬＡ－５２という商品名で市販されているものが好ましい。 The hindered amine compound is preferably commercially available from Ciba Japan Co., Ltd. under the trade name of Tinuvin 144 and Tinuvin 770, and from ADEKA Co., Ltd. under the name of ADK STAB LA-52.
　上記イオウ系化合物は、例えば、住友化学（株）から、Ｓｕｍｉｌｉｚｅｒ　ＴＰＬ－ＲおよびＳｕｍｉｌｉｚｅｒ　ＴＰ－Ｄという商品名で市販されているものが好ましい。 The above-mentioned sulfur compounds are preferably those commercially available from Sumitomo Chemical Co., Ltd. under the trade names Sumilizer TPL-R and Sumilizer TP-D.
　上記二重結合系化合物は、住友化学（株）から、Ｓｕｍｉｌｉｚｅｒ－ＧＭおよびＳｕｍｉｌｉｚｅｒ－ＧＳという商品名で市販されているものが好ましい。 The above-mentioned double bond compounds are preferably those commercially available from Sumitomo Chemical Co., Ltd. under the trade names Sumilizer-GM and Sumilizer-GS.
　さらに、酸捕捉剤として米国特許第４，１３７，２０１号明細書に記載されているようなエポキシ基を有する化合物を含有させることも可能である。 Furthermore, it is possible to contain a compound having an epoxy group as described in US Pat. No. 4,137,201 as an acid scavenger.
　これらの酸化防止剤等は、再生使用される際の工程に合わせて適宜添加する量が決められるが、一般には、フィルムの主原料である樹脂に対して、０．０５～５質量％の範囲で添加される。 The amount of these antioxidants and the like to be added is appropriately determined in accordance with the process at the time of recycling. Generally, the range of 0.05 to 5% by mass with respect to the resin as the main raw material of the film. Is added.
　これらの酸化防止剤、熱劣化防止剤は、一種のみを用いるよりも数種の異なった系の化合物を併用することで相乗効果を得ることができる。例えば、ラクトン系、リン系、フェノール系および二重結合系化合物の併用は好ましい。 These antioxidants and thermal degradation inhibitors can obtain a synergistic effect by using several different types of compounds in combination rather than using only one kind. For example, the combined use of lactone, phosphorus, phenol and double bond compounds is preferred.
　《着色剤》
　本発明においては、着色剤を使用しても良い。通常、着色剤とは染料や顔料を意味するが、本発明では、液晶画面の色調を青色調にする効果またはイエローインデックス（黄色度）の調整、ヘイズの低減効果を有するものを指す。 《Colorant》
In the present invention, a colorant may be used. Usually, the colorant means a dye or a pigment, but in the present invention, it means an agent having the effect of making the color tone of the liquid crystal screen blue, adjusting the yellow index (yellowness), and reducing haze.
　着色剤としては各種の染料、顔料が使用可能だが、アントラキノン染料、アゾ染料、フタロシアニン顔料などが有効である。 Various dyes and pigments can be used as the colorant, but anthraquinone dyes, azo dyes, phthalocyanine pigments and the like are effective.
　《紫外線吸収剤》
　本発明に用いられる紫外線吸収剤は特に限定されないが、例えばオキシベンゾフェノン系化合物、ベンゾトリアゾール系化合物、サリチル酸エステル系化合物、ベンゾフェノン系化合物、シアノアクリレート系化合物、トリアジン系化合物、ニッケル錯塩系化合物、無機粉体などが挙げられる。高分子型の紫外線吸収剤としてもよい。本発明で好ましく用いられる紫外線吸収剤は、透明性が高く、偏光板や液晶素子の劣化を防ぐ効果に優れたベンゾトリアゾール系紫外線吸収剤やベンゾフェノン系紫外線吸収剤が好ましく、不要な着色がより少ないベンゾトリアゾール系紫外線吸収剤が特に好ましい。本発明に用いられる紫外線吸収剤の具体例として、例えばチバ・ジャパン（株）製のＴＩＮＵＶＩＮ１０９、ＴＩＮＵＶＩＮ１７１、ＴＩＮＵＶＩＮ３２６、ＴＩＮＵＶＩＮ３２７、ＴＩＮＵＶＩＮ３２８、ＴＩＮＵＶＩＮ９００、ＴＩＮＵＶＩＮ９２８、ＡＤＥＫＡ（株）製のＬＡ－３１等を好ましく用いることができるが、本発明はこれらに限定されるものではない。また、紫外線吸収剤としては高分子紫外線吸収剤も好ましく用いることができ、特に特開平６－１４８４３０号記載のポリマータイプの紫外線吸収剤が好ましく用いられる。紫外線吸収剤は単独で用いても良いし、二種以上の混合物であっても良い。 <Ultraviolet absorber>
Although the ultraviolet absorber used in the present invention is not particularly limited, for example, oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, triazine compounds, nickel complex compounds, inorganic powders Examples include the body. It is good also as a polymer type ultraviolet absorber. The UV absorber preferably used in the present invention is preferably a benzotriazole-based UV absorber or a benzophenone-based UV absorber that has high transparency and is excellent in the effect of preventing the deterioration of the polarizing plate and the liquid crystal element, and has less unnecessary coloring. Benzotriazole ultraviolet absorbers are particularly preferred. As specific examples of the ultraviolet absorber used in the present invention, for example, TINUVIN109, TINUVIN171, TINUVIN326, TINUVIN327, TINUVIN328, TINUVIN900, TINUVIN928 manufactured by Ciba Japan Co., Ltd., LA-31 manufactured by ADEKA Corporation, etc. are preferably used. However, the present invention is not limited to these. As the UV absorber, a polymer UV absorber can also be preferably used, and in particular, a polymer type UV absorber described in JP-A-6-148430 is preferably used. An ultraviolet absorber may be used independently and 2 or more types of mixtures may be sufficient as it.
　紫外線吸収剤の使用量は化合物の種類、使用条件などにより一様ではないが、セルロースエステルフィルムの乾燥膜厚が３０～２００μｍの場合は、セルロースエステルフィルムに対して０．５～４．０質量％が好ましく、０．６～３．５質量％がさらに好ましい。 The amount of the UV absorber used is not uniform depending on the type of compound and the use conditions, but when the dry film thickness of the cellulose ester film is 30 to 200 μm, 0.5 to 4.0 mass with respect to the cellulose ester film. % Is preferable, and 0.6 to 3.5% by mass is more preferable.
　＜本発明のフィルムの製膜方法＞
　本発明のフィルムは溶液流延方法、溶融流延によって作製することができるが、以下はまず溶融製膜方法について述べる。 <Method for Forming Film of the Present Invention>
The film of the present invention can be produced by a solution casting method or a melt casting method. First, the melt film forming method will be described below.
　（溶融流延製膜方法）
　溶融製膜法によるフィルムの成形法は、溶融押出し成形法、プレス成形法、インフレーション法、射出成形法、ブロー成形法、延伸成形法などに分類できる。これらの中で、機械的強度および表面精度などに優れるフィルムを得るためには、溶融押出し成形法が優れている。 (Melt casting method)
Film forming methods by the melt film forming method can be classified into melt extrusion forming methods, press forming methods, inflation methods, injection forming methods, blow forming methods, stretch forming methods, and the like. Among these, in order to obtain a film having excellent mechanical strength and surface accuracy, the melt extrusion molding method is excellent.
　以下、溶融押出し成形法を例にとり、本発明のフィルムの製造方法について説明する。フィルムの製造方法において、溶融押出しの条件は一般的な熱可塑性樹脂に用いられる条件と同様にして行うことができる。 Hereinafter, the film production method of the present invention will be described by taking the melt extrusion molding method as an example. In the method for producing a film, the conditions for melt extrusion can be performed in the same manner as the conditions used for general thermoplastic resins.
　《ペレット製造工程》
　溶融押出しに用いる複数の原材料は、あらかじめ混練してペレット化しておくことが好ましい。 << Pellet manufacturing process >>
A plurality of raw materials used for melt extrusion are preferably kneaded and pelletized in advance.
　ペレット化は公知の方法でよく、例えば、乾燥したアクリル樹脂、セルロースエステル樹脂や添加剤をフィーダーで押出機に供給し一軸や二軸の押出機を用いて混練し、ダイからストランド状に押出し、水冷または空冷し、カッティングすることでできる。 Pelletization may be a known method, for example, dry acrylic resin, cellulose ester resin and additives are fed to an extruder with a feeder and kneaded using a uniaxial or biaxial extruder, extruded from a die into a strand, It can be done by water cooling or air cooling and cutting.
　紫外線吸収剤やマット剤などは、高濃度のマスターペレットを作製して、フィルム製膜時に押出し機中でメインのペレットと混合してもよい。 For UV absorbers and matting agents, high concentration master pellets may be prepared and mixed with main pellets in an extruder during film formation.
　原材料は、押出しする前に乾燥しておくことが原材料の分解を防止する上で重要である。特にセルロースエステル樹脂は吸湿しやすいので、除湿熱風乾燥機や真空乾燥機で７０～１４０℃で３時間以上乾燥し、水分率を２００ｐｐｍ以下、さらに１００ｐｐｍ以下にしておくことが好ましい。 It is important to dry the raw material before extruding it to prevent the raw material from being decomposed. In particular, since the cellulose ester resin easily absorbs moisture, it is preferable to dry it at 70 to 140 ° C. for 3 hours or more with a dehumidifying hot air dryer or a vacuum dryer so that the moisture content is 200 ppm or less, and further 100 ppm or less.
　添加剤は、押出し機に供給する前に混合しておいてもよいし、それぞれ個別のフィーダーで供給してもよい。酸化防止剤等少量の添加剤は、均一に混合するため、事前に混合しておくことが好ましい。 Additives may be mixed before being supplied to the extruder, or may be supplied by individual feeders. A small amount of an additive such as an antioxidant is preferably mixed in advance in order to mix uniformly.
　真空ナウターミキサーなどが乾燥と混合を同時にできるので好ましい。また、フィーダー部やダイからの出口など空気と触れる箇所は、除湿空気や除湿した窒素ガスなどの雰囲気下にすることが好ましい。 A vacuum nauter mixer is preferable because it can dry and mix simultaneously. In addition, it is preferable that a portion that comes into contact with air such as an outlet from a feeder part or a die is in an atmosphere of dehumidified air or dehumidified nitrogen gas.
　また、押出し機への供給ホッパー等は保温しておくと吸湿防止できるので好ましい。 In addition, it is preferable to keep the supply hopper to the extruder warm so as to prevent moisture absorption.
　押出し機は、せん断力を抑え、樹脂が劣化（分子量低下、着色、ゲル生成等）しないようになるべく低温で加工することが好ましいため、例えば、二軸押出し機の場合、深溝タイプのスクリューを用いて同方向に回転させることが好ましい。混錬の均一性から、噛み合いタイプが好ましい。ニーダーディスクは混錬性を向上できるが、せん断発熱に注意が必要である。 The extruder is preferably processed at a low temperature so as to suppress shearing force and prevent the resin from deteriorating (molecular weight reduction, coloring, gel formation, etc.). For example, in the case of a twin screw extruder, a deep groove type screw is used. Are preferably rotated in the same direction. From the uniformity of kneading, the meshing type is preferable. Kneader discs can improve kneadability, but care must be taken against shearing heat generation.
　ベント孔からの吸引は必要に応じて行えばよい。低温であれば揮発成分はほとんど発生しないのでベント孔なしでもよい。 ¡Suction from the vent hole may be performed as necessary. Since there is almost no volatile component at low temperatures, there may be no vent hole.
　ペレットの色は、黄味の指標であるｂ＊値が－５～１０の範囲にあることが好ましく、－１～８の範囲にあることがさらに好ましく、－１～５の範囲にあることがより好ましい。ｂ＊値は分光測色計ＣＭ－３７００ｄ（コニカミノルタセンシング（株）製）で、光源はＤ６５（色温度６５０４Ｋ）を用い、視野角１０°で測定することができる。 As for the color of the pellet, the b * value, which is an index of yellowness, is preferably in the range of -5 to 10, more preferably in the range of -1 to 8, and preferably in the range of -1 to 5. More preferred. The b * value can be measured at a viewing angle of 10 ° using a spectrocolorimeter CM-3700d (manufactured by Konica Minolta Sensing Co., Ltd.) and a light source of D65 (color temperature 6504K).
　以上のようにして得られたペレットを用いてフィルム製膜を行うことが好ましいが、ペレット化せずに、原材料の粉末をそのままフィーダーで押出し機に供給してフィルム製膜することも可能である。 It is preferable to form a film using the pellets obtained as described above, but it is also possible to form a film by feeding raw material powder directly to an extruder with a feeder without pelletization. .
　《溶融物押出し工程》
　ペレットなどの材料は予め乾燥させておくことが好ましい。真空または減圧乾燥機や除湿熱風乾燥機等で水分を２００ｐｐｍ以下、好ましくは１００ｐｐｍ以下に乾燥させることが望ましい。 <Melten extrusion process>
It is preferable to dry materials such as pellets in advance. It is desirable to dry the moisture to 200 ppm or less, preferably 100 ppm or less using a vacuum or reduced pressure drier or a dehumidifying hot air drier.
　除湿熱風や真空または減圧下で乾燥したポリマーを一軸や二軸タイプの押出し機を用いて溶融し、リーフディスクタイプのフィルターなどでろ過して異物を除去した後、流延ダイからフィルム状に流延し、冷却ロール上で固化させる。 The polymer dried under dehumidified hot air, vacuum or reduced pressure is melted using a single or twin screw type extruder and filtered with a leaf disk type filter etc. to remove foreign matter, and then flowed in a film form from a casting die. And solidify on a cooling roll.
　押出し機は、市販の押出し機を使用可能であるが、溶融混練押出し機が好ましく、単軸押出し機でも二軸押出し機でもよい。 As the extruder, a commercially available extruder can be used, but a melt-kneading extruder is preferable, and a single-screw extruder or a twin-screw extruder may be used.
　供給ホッパーから押出し機へ導入する部位、および押出し機内は窒素ガス等の不活性ガスで置換するか、あるいは減圧すると、酸素の濃度を下げることで酸化分解を抑制することができるため好ましい。 It is preferable to replace the portion introduced from the supply hopper into the extruder and the inside of the extruder with an inert gas such as nitrogen gas, or to reduce the pressure, since the oxidative decomposition can be suppressed by lowering the oxygen concentration.
　押出し機内のフィルム構成材料を溶融させる温度は、フィルム構成材料の粘度や吐出量、製造するシートの厚み等によって好ましい条件が異なるが、１５０～３００℃が好ましく、１８０～２７０℃がより好ましく、２００～２６０℃がさらに好ましい。温度が低すぎると溶解不良や溶融粘度の上昇が発生し、温度が高すぎると材料の熱劣化が起こる。 The temperature at which the film constituent material in the extruder is melted varies depending on the viscosity and discharge amount of the film constituent material, the thickness of the sheet to be produced, etc., but is preferably 150 to 300 ° C., more preferably 180 to 270 ° C., 200 More preferred is ~ 260 ° C. If the temperature is too low, poor dissolution and an increase in melt viscosity occur, and if the temperature is too high, thermal degradation of the material occurs.
　押出し時の溶融粘度は、１～１００００Ｐａ・ｓ、好ましくは１０～１０００Ｐａ・ｓである。溶融粘度が高すぎると圧力の上昇によって、押出し機内での滞留時間が長くなる。押出し機内でのフィルム構成材料の滞留時間は短い方が好ましく、５分以内、好ましくは３分以内、より好ましくは２分以内である。 The melt viscosity at the time of extrusion is 1 to 10000 Pa · s, preferably 10 to 1000 Pa · s. If the melt viscosity is too high, the residence time in the extruder becomes longer due to an increase in pressure. The residence time of the film constituent material in the extruder is preferably shorter, and is within 5 minutes, preferably within 3 minutes, more preferably within 2 minutes.
　滞留時間は、押出し機の種類、押出す条件にも左右されるが、材料の供給量やＬ／Ｄ、スクリュー回転数、スクリューの溝の深さ等を調整することにより短縮することが可能である。 The residence time depends on the type of extruder and the extrusion conditions, but it can be shortened by adjusting the material supply amount, L / D, screw rotation speed, screw groove depth, etc. is there.
　押出し機のスクリューの形状や回転数等は、フィルム構成材料の粘度や吐出量等により適宜選択される。本発明において押出し機でのせん断速度は、１／秒～１００００／秒、好ましくは５／秒～１０００／秒、より好ましくは１０／秒～１００／秒である。 The shape of the screw and the number of revolutions of the extruder are appropriately selected depending on the viscosity of the film constituting material, the discharge amount, and the like. In the present invention, the shear rate in the extruder is from 1 / second to 10,000 / second, preferably from 5 / second to 1000 / second, and more preferably from 10 / second to 100 / second.
　押出し機から押出された溶融樹脂は、流延ダイに送られ、流延ダイのスリットからフィルム状に押出される。流延ダイはシートやフィルムを製造するために用いられるものであれば特に限定はされない。 The molten resin extruded from the extruder is sent to a casting die and extruded into a film from the slit of the casting die. The casting die is not particularly limited as long as it is used for producing a sheet or a film.
　流延ダイの材質としては、ハードクロム、炭化クロム、窒化クロム、炭化チタン、炭窒化チタン、窒化チタン、超鋼、セラミック（タングステンカーバイド、酸化アルミ、酸化クロム）等を溶射もしくはメッキし、表面加工としてバフ、＃１０００番手以降の砥石を用いるラッピング、＃１０００番手以上のダイヤモンド砥石を用いる平面切削（切削方向は樹脂の流れ方向に垂直な方向）、電解研磨、電解複合研磨等の加工を施したもの等が挙げられる。流延ダイのリップ部の好ましい材質は、流延ダイと同様である。またリップ部の表面精度は０．５Ｓ以下が好ましく、０．２Ｓ以下がより好ましい。 As the material of the casting die, hard chromium, chromium carbide, chromium nitride, titanium carbide, titanium carbonitride, titanium nitride, super steel, ceramic (tungsten carbide, aluminum oxide, chromium oxide), etc. are sprayed or plated and surface processed Buffing, lapping using a # 1000 or higher whetstone, surface cutting using a diamond whetstone of # 1000 or higher (the cutting direction is perpendicular to the resin flow direction), electrolytic polishing, electrolytic composite polishing, etc. And the like. The preferred material of the lip portion of the casting die is the same as that of the casting die. The surface accuracy of the lip is preferably 0.5S or less, and more preferably 0.2S or less.
　この流延ダイのスリットは、そのギャップが調整可能なように構成されている。 The slit of this casting die is configured so that the gap can be adjusted.
　流延ダイのスリットを形成する一対のリップのうち、一方は剛性の低い変形しやすいフレキシブルリップであり、他方は固定リップであることがギャップ調整のし易さの点で好ましい。 Of the pair of lips forming the slit of the casting die, one is a flexible lip having low rigidity and easily deformed, and the other is preferably a fixed lip from the viewpoint of easy gap adjustment.
　ギャップ調整のため、多数のヒートボルトが流延ダイの幅方向に一定ピッチで配列されている。各ヒートボルトには、埋め込み電気ヒーターと冷却媒体通路とを具えたブロックが設けられ、各ヒートボルトが各ブロックを縦に貫通している。 ) A large number of heat bolts are arranged at a constant pitch in the width direction of the casting die for gap adjustment. Each heat bolt is provided with a block having an embedded electric heater and a cooling medium passage, and each heat bolt vertically penetrates each block.
　ヒートボルトの基部はダイ本体に固定され、先端はフレキシブルリップの外面に当接している。そしてブロックを常時空冷しながら、埋め込み電気ヒーターの入力を増減してブロックの温度を上下させ、これによりヒートボルトを熱伸縮させて、フレキシブルリップを変位させてアクリルフィルムの厚さを調整する。 The base of the heat bolt is fixed to the die body, and the tip is in contact with the outer surface of the flexible lip. Then, while constantly cooling the block, the input of the embedded electric heater is increased or decreased to increase or decrease the temperature of the block, thereby causing the heat bolt to thermally expand and contract to displace the flexible lip and adjust the thickness of the acrylic film.
　ダイ後流の所要箇所に厚さ計を設け、これによって検出されたウェブ厚さ情報を制御装置にフィードバックし、この厚さ情報を制御装置で設定厚み情報と比較し、同装置から来る補正制御量の信号によってヒートボルトの発熱体の電力またはオン率を制御するようにすることもできる。 Thickness gauges are installed at the required locations in the wake of the die, and the web thickness information detected thereby is fed back to the control device. The thickness information is compared with the set thickness information by the control device, and correction control comes from the same device. It is also possible to control the power or the ON rate of the heat bolt heating element by the amount signal.
　ヒートボルトは、好ましくは、長さ２０～４０ｃｍ、直径７～１４ｍｍを有し、複数（例えば数十本）のヒートボルトがピッチ２０～４０ｍｍで配列されていることが好ましい。 The heat bolt preferably has a length of 20 to 40 cm and a diameter of 7 to 14 mm, and a plurality of (for example, several tens) heat bolts are preferably arranged at a pitch of 20 to 40 mm.
　ヒートボルトの代わりに、手動で軸方向に前後動させることによりスリットギャップを調節するボルトを主体とするギャップ調節部材を設けてもよい。 Instead of the heat bolt, a gap adjusting member mainly composed of a bolt for adjusting the slit gap by manually moving back and forth in the axial direction may be provided.
　ギャップ調節部材によって調節されたスリットギャップは、通常２００～２０００μｍ、好ましくは３００～１０００μｍ、より好ましくは４００～８００μｍである。 The slit gap adjusted by the gap adjusting member is usually 200 to 2000 μm, preferably 300 to 1000 μm, more preferably 400 to 800 μm.
　押出し流量は、ギヤポンプを導入するなどして安定に行うことが好ましい。また、異物の除去に用いるフィルターは、ステンレス繊維焼結フィルターが好ましく用いられる。 The extrusion flow rate is preferably carried out stably by introducing a gear pump. Further, a stainless fiber sintered filter is preferably used as a filter used for removing foreign substances.
　ステンレス繊維焼結フィルターは、ステンレス繊維体を複雑に絡み合った状態を作り出した上で圧縮し接触箇所を焼結し一体化したもので、その繊維の太さと圧縮量により密度を変え、ろ過精度を調整できる。 A stainless steel fiber sintered filter is a united stainless steel fiber body that is intricately entangled and then compressed and sintered at the contact location. The density is changed according to the thickness of the fiber and the amount of compression, and the filtration accuracy is improved. Can be adjusted.
　フィルターはろ過精度の異なるろ過材を組み合わせて多層体としたものが好ましい。また、ろ過精度を順次上げていく構成としたり、ろ過精度の粗、密を繰り返したりする方法をとることで、フィルターのろ過寿命が延び、異物やゲルなどの補足精度も向上できるので好ましい。 It is preferable that the filter is a multilayer body combining filter media having different filtration accuracy. Further, it is preferable to adopt a configuration in which the filtration accuracy is sequentially increased or a method in which coarse and dense filtration accuracy is repeated, so that the filtration life of the filter is extended and the accuracy of supplementing foreign matters and gels can be improved.
　ダイに傷や異物が付着するとスジ状の欠陥が発生する場合がある。このような欠陥のことをダイラインと呼ぶが、ダイライン等の表面の欠陥を小さくするためには、ダイの内部やリップにキズ等が極力無いものを使用し、押出し機からダイまでの配管には樹脂の滞留部が極力少なくなるような構造にすることが好ましい。 ∙ If flaws or foreign matter adhere to the die, streaky defects may occur. Such a defect is called a die line, but in order to reduce surface defects such as the die line, use one that has as little scratches as possible in the inside of the die and lip, and piping from the extruder to the die. It is preferable to have a structure in which the resin retention portion is minimized.
　押出し機やダイなどの溶融樹脂と接触する内面は、表面粗さを小さくしたり、表面エネルギーの低い材質を用いるなどして、溶融樹脂が付着し難い表面加工が施されていることが好ましい。具体的には、ハードクロムメッキやセラミック溶射したものを表面粗さ０．２Ｓ以下となるように研磨したものが挙げられる。 It is preferable that the inner surface that comes into contact with the molten resin, such as an extruder or a die, is subjected to surface treatment that makes it difficult for the molten resin to adhere to the surface by reducing the surface roughness or using a material with low surface energy. Specifically, a hard chrome plated or ceramic sprayed material is polished so that the surface roughness is 0.2 S or less.
　可塑剤などの添加剤は、あらかじめ樹脂と混合しておいてもよいし、押し出し機の途中で練り込んでもよい。均一に添加するために、スタチックミキサーなどの混合装置を用いることが好ましい。 Additives such as plasticizers may be mixed with the resin in advance, or may be kneaded in the middle of the extruder. In order to add uniformly, it is preferable to use a mixing apparatus such as a static mixer.
　《冷却ロール》
　冷却ロールには特に制限はないが、高剛性の金属ロールで内部に温度制御可能な熱媒体または冷媒体が流れるような構造を備えるロールであり、大きさは溶融押出しされたフィルムを冷却するのに十分な大きさであればよく、通常冷却ロールの直径は１００ｍｍから１ｍ程度である。 《Cooling roll》
There is no particular limitation on the cooling roll, but it is a roll having a structure in which a heat medium or a coolant body in which the temperature can be controlled flows through a highly rigid metal roll, and the size of the roll is used to cool the melt-extruded film. The diameter of the cooling roll is usually about 100 mm to 1 m.
　冷却ロールの表面材質は、炭素鋼、ステンレス、アルミニウム、チタンなどが挙げられる。さらに表面の硬度をあげたり、樹脂との剥離性を改良したりするため、ハードクロムメッキや、ニッケルメッキ、非晶質クロムメッキなどや、セラミック溶射等の表面処理を施すことが好ましい。 The surface material of the cooling roll includes carbon steel, stainless steel, aluminum, titanium and the like. Further, in order to increase the surface hardness or improve the releasability from the resin, it is preferable to perform a surface treatment such as hard chrome plating, nickel plating, amorphous chrome plating, or ceramic spraying.
　冷却ロールは、肉厚が２０～３０ｍｍ程度のシームレスな鋼管製で、表面が鏡面に仕上げられている。 The cooling roll is made of seamless steel pipe with a wall thickness of about 20-30mm, and the surface is mirror finished.
　冷却ロール表面の表面粗さは、Ｒａで０．１μｍ以下とすることが好ましく、さらに０．０５μｍ以下とすることが好ましい。ロール表面が平滑であるほど、得られるフィルムの表面も平滑にできる。 The surface roughness of the cooling roll surface is preferably 0.1 μm or less in terms of Ra, and more preferably 0.05 μm or less. The smoother the roll surface, the smoother the surface of the resulting film.
　冷却ロールは、少なくとも一つであり、二つ以上有しているのが好ましい。一つしかない場合、冷却ロールの表面温度Ｔｒは、Ｔｇ－５０≦Ｔｒ≦Ｔｇに設定される。二つ以上の場合、第１冷却ロールの表面温度Ｔｒ１と第２冷却ロールの表面温度Ｔｒ２は、Ｔｇ－５０≦Ｔｒ１≦Ｔｇ、Ｔｇ－５０≦Ｔｒ２≦Ｔｇに設定される。 The cooling roll is at least one and preferably has two or more. When there is only one, the surface temperature Tr of the cooling roll is set to Tg−50 ≦ Tr ≦ Tg. In the case of two or more, the surface temperature Tr1 of the first cooling roll and the surface temperature Tr2 of the second cooling roll are set to Tg-50 ≦ Tr1 ≦ Tg and Tg-50 ≦ Tr2 ≦ Tg.
　好ましくは、Ｔｒ２＞Ｔｒ１であり、０＜Ｔｒ２－Ｔｒ１＜５０である。 Preferably, Tr2> Tr1, and 0 <Tr2-Tr1 <50.
　このことにより、冷却ロール上への添加剤の凝結量がコントロールされ、さらにセルロースフィルムに再溶融されることになる。 This controls the amount of the additive to condense on the cooling roll and further remelts the cellulose film.
　セルロースエステルフィルムと第１および第２冷却ロールとの接触時間によっても再溶解を促進することができるが、本発明においては１．０秒以上、３．０秒以下が好ましい。 Although re-dissolution can be promoted also by the contact time between the cellulose ester film and the first and second cooling rolls, in the present invention, 1.0 second or more and 3.0 seconds or less are preferable.
　なお、接触時間は、フィルムとローラとが接しはじめる接点と剥離されはじめる接点との円周の距離と、フィルムの搬送速度から算出した秒数で表した。 The contact time was expressed by the number of seconds calculated from the circumferential distance between the contact point at which the film and the roller began to contact and the contact point at which the film began to peel off, and the film conveyance speed.
　第２冷却ロールの周速度Ｒ２は第１冷却ロールの周速度Ｒ１よりも大きいことが好ましい。つまりこの２つのロール間のフィルムに張力が働き、フィルムと第１ロールとの密着性が高まる。この周速度の比は１．００～１．０５の範囲が好ましく、１．０５を超えるとフィルムが破断する危険性がある。同様に、第３以降のロール周速度がその直前の冷却ロールの周速度より大きいことが好ましい。 The peripheral speed R2 of the second cooling roll is preferably larger than the peripheral speed R1 of the first cooling roll. That is, tension acts on the film between the two rolls, and the adhesion between the film and the first roll is increased. The ratio of the peripheral speeds is preferably in the range of 1.00 to 1.05, and if it exceeds 1.05, there is a risk that the film breaks. Similarly, it is preferable that the third and subsequent roll peripheral speeds are greater than the peripheral speed of the cooling roll immediately before.
　《弾性タッチロール》
　冷却ロールに当接するタッチロールは、表面が弾性を有し、冷却ロールへの押圧力によって冷却ロールの表面に沿って変形し、冷却ロールとの間にニップを形成することができる、弾性タッチロールであることが好ましい。 《Elastic touch roll》
The touch roll that abuts on the cooling roll has an elastic surface, and can be deformed along the surface of the cooling roll by a pressing force to the cooling roll to form a nip with the cooling roll. It is preferable that
　本発明に係る弾性タッチロールとしては、特許第３１９４９０４号、特許第３４２２７９８号、特開平０３－１２４４２５号、特開平０８－２２４７７２号、特開平０７－１００９６０号、特開平１０－２７２６７６号公報、ＷＯ９７／０２８９５０号パンフレット、特開平１１－２３５７４７号、特開２００２－３６３３２号、特開２００２－３６３３３号、特開２００５－１７２９４０号や特開２００５－２８０２１７号公報に記載されているような弾性タッチロールを使用することができる。 Examples of the elastic touch roll according to the present invention include Japanese Patent No. 3194904, Japanese Patent No. 3422798, Japanese Patent Application Laid-Open No. 03-124425, Japanese Patent Application Laid-Open No. 08-224772, Japanese Patent Application Laid-Open No. 07-1000096, Japanese Patent Application Laid-Open No. 10-272676, and WO 97. / 028950, JP-A-11-235747, JP-A-2002-36332, JP-A-2002-36333, JP-A-2005-172940 and JP-A-2005-280217 Can be used.
　本発明で用いる弾性タッチロールは、金属製外筒と内筒との２重構造になっており、その間に冷却流体を流せるように空間を有しているものである。 The elastic touch roll used in the present invention has a double structure of a metal outer cylinder and an inner cylinder, and has a space so that a cooling fluid can flow between them.
　さらに、金属製外筒は弾性を有していることにより、タッチロール表面の温度を精度よく制御でき、かつ適度に弾性変形する性質を利用して、長手方向にフィルムを押圧する距離が稼げるとの効果を有することにより、液晶表示装置で画像を表示したときに、明暗のスジや斑点むらがないという本発明の効果が得られるのである。 Furthermore, because the metal outer cylinder has elasticity, it can control the temperature of the surface of the touch roll with high accuracy, and by utilizing the property of being elastically deformed appropriately, the distance for pressing the film in the longitudinal direction can be increased. With this effect, the effect of the present invention can be obtained that there are no bright and dark stripes and uneven spots when an image is displayed on a liquid crystal display device.
　金属製外筒の肉厚の範囲は、０．００３≦（金属製外筒の肉厚）／（タッチロール半径）≦０．０３であれば、適度な弾性となり好ましい。タッチロールの半径が大きければ金属外筒の肉厚が厚くても適度に撓むことができる。金属製外筒の肉厚があまり薄すぎると強度が不足し、破損の懸念がある。一方、厚すぎると、ロール質量が重くなりすぎ、回転むらの懸念がある。従って、金属外筒の肉厚は、０．１～５ｍｍであることが好ましい。 If the range of the thickness of the metal outer cylinder is 0.003 ≦ (thickness of the metal outer cylinder) / (touch roll radius) ≦ 0.03, it is preferable because the elasticity is appropriate. If the radius of the touch roll is large, even if the thickness of the metal outer cylinder is thick, the touch roll can be appropriately bent. If the thickness of the metal outer cylinder is too thin, the strength is insufficient and there is a concern of breakage. On the other hand, if it is too thick, the roll mass becomes too heavy and there is a concern about uneven rotation. Therefore, the thickness of the metal outer cylinder is preferably 0.1 to 5 mm.
　弾性タッチロールの直径は１００ｍｍ～６００ｍｍ、ロール有効幅Ｌ＝５００～１６００ｍｍで、ｒ／Ｌ＜１で横長の形状が好ましい。 The diameter of the elastic touch roll is preferably 100 mm to 600 mm, the effective roll width L = 500 to 1600 mm, and a horizontally long shape with r / L <1 is preferable.
　金属外筒表面の表面粗さは、算術平均粗さＲａで０．１μｍ以下とすることが好ましく、さらに０．０５μｍ以下とすることが好ましい。ロール表面が平滑であるほど、得られるフィルムの表面も平滑にできるのである。 The surface roughness of the metal outer cylinder surface is preferably 0.1 μm or less, more preferably 0.05 μm or less, in terms of arithmetic average roughness Ra. The smoother the roll surface, the smoother the surface of the resulting film.
　金属外筒の材質は、平滑で適度な弾性があり、耐久性があることが求められる。このため、炭素鋼、ステンレス、チタン、電鋳法で製造されたニッケルなどが好ましく用いることができる。さらにその表面の硬度をあげたり、樹脂との剥離性を改良したりするため、ハードクロムメッキや、ニッケルメッキ、非晶質クロムメッキなどや、セラミック溶射等の表面処理を施すことが好ましい。表面加工した表面はさらに研磨し上述した表面粗さとすることが好ましい。 The material of the metal outer cylinder is required to be smooth and have moderate elasticity and durability. For this reason, carbon steel, stainless steel, titanium, nickel produced by electroforming, etc. can be preferably used. Further, in order to increase the hardness of the surface or improve the releasability from the resin, it is preferable to perform a surface treatment such as hard chrome plating, nickel plating, amorphous chrome plating, or ceramic spraying. It is preferable that the surface processed is further polished to have the surface roughness described above.
　内筒は、炭素鋼、ステンレス、アルミニウム、チタンなどの軽量で剛性のある金属製内筒であることが好ましい。内筒に剛性をもたせることで、ロールの回転ぶれを抑えることができる。内筒の肉厚は、外筒の２～１０倍とすることで十分な剛性が得られる。 The inner cylinder is preferably a lightweight and rigid metallic inner cylinder such as carbon steel, stainless steel, aluminum, titanium or the like. By giving rigidity to the inner cylinder, it is possible to suppress the rotational shake of the roll. A sufficient rigidity can be obtained by setting the thickness of the inner cylinder to 2 to 10 times that of the outer cylinder.
　内筒にはさらにシリコーン、フッ素ゴムなどの樹脂製弾性材料が被覆されていてもよい。 The inner cylinder may be further covered with a resin elastic material such as silicone or fluororubber.
　冷却流体を流す空間の構造は、ロール表面の温度を均一に制御できるものであればよく、例えば、巾方向に行きと戻りが交互に流れるようにしたり、スパイラル状に流れるようにしたりすることでロール表面の温度分布の小さい温度制御ができる。 The structure of the space through which the cooling fluid flows can be any structure as long as the temperature of the roll surface can be controlled uniformly. For example, the flow and the return flow alternately in the width direction or spirally. Temperature control with a small temperature distribution on the roll surface is possible.
　冷却流体は、特に制限はなく、使用する温度域に合わせて、水やオイルを使用できる。 The cooling fluid is not particularly limited, and water or oil can be used according to the temperature range to be used.
　弾性タッチロールの表面温度（Ｔｒ０）は、フィルムのガラス転移温度（Ｔｇ）より低いことが好ましい。Ｔｇより高いと、フィルムとロールとの剥離性が劣る場合がある。Ｔｇ－５０℃～Ｔｇであることがさらに好ましい。 The surface temperature (Tr0) of the elastic touch roll is preferably lower than the glass transition temperature (Tg) of the film. If it is higher than Tg, the peelability between the film and the roll may be inferior. More preferably, it is Tg-50 ° C. to Tg.
　本発明で用いる弾性タッチロールは、巾方向の中央部が端部より径が大きいクラウンロールの形状とすることが好ましい。 The elastic touch roll used in the present invention preferably has a crown roll shape in which the central portion in the width direction has a larger diameter than the end portion.
　タッチロールは、その両端部を加圧手段でフィルムに押圧するのが一般的であるが、この場合、タッチロールが撓むため、端部にいくほど強く押圧されてしまう現象がある。ロールをクラウン形状にすることで高度に均一な押圧が可能となる。 The touch roll is generally pressed against the film by pressing means at both ends, but in this case, since the touch roll is bent, there is a phenomenon that the touch roll is strongly pressed toward the end. Highly uniform pressing is possible by making the roll into a crown shape.
　本発明で用いる弾性タッチロールの幅は、フィルム幅よりも広くするとフィルム全体を冷却ロールに密着できるので好ましいが、ドロー比が大きくなると、フィルムの両端部がネックイン現象により耳高（端部の膜厚が厚くなる）になる場合があり、この場合は、耳高部を逃げるように、金属製外筒の幅をフィルム幅より狭くしてもよい。あるいは、金属製外筒の外径を小さくして耳高部を逃げてもよい。 The width of the elastic touch roll used in the present invention is preferably larger than the film width because the entire film can be closely attached to the cooling roll. However, when the draw ratio is increased, both end portions of the film become ear height (end portion) due to a neck-in phenomenon. In this case, the width of the metal outer cylinder may be made narrower than the film width so as to escape from the high ear portion. Alternatively, the outer diameter of the metal outer cylinder may be reduced to escape the ear height.
　弾性タッチロールの撓みを防止するため、冷却ロールに対してタッチロールの反対側にサポートロールを配してもよい。 In order to prevent bending of the elastic touch roll, a support roll may be arranged on the opposite side of the touch roll with respect to the cooling roll.
　弾性タッチロールの汚れを清掃する装置を配してもよい。清掃装置としては、例えば、ロール表面を必要により溶剤を浸透させた不織布などの部材をロールに押し当てる方法、液体中にロールを接触させる方法、コロナ放電やグロー放電などのプラズマ放電によりロール表面の汚れを揮発させる方法などが好ましく用いることができる。 ¡A device for cleaning dirt on the elastic touch roll may be provided. As the cleaning device, for example, a method of pressing the roll surface with a member such as a nonwoven fabric infiltrated with a solvent if necessary, a method of bringing the roll into contact with a liquid, a plasma discharge such as corona discharge or glow discharge, A method for volatilizing dirt can be preferably used.
　弾性タッチロールの表面温度を均一にするため、タッチロールに温調ロールを接触させたり、温度制御された空気を吹き付けたり、液体などの熱媒体を接触させてもよい。 In order to make the surface temperature of the elastic touch roll uniform, the temperature control roll may be brought into contact with the touch roll, temperature-controlled air may be sprayed, or a heat medium such as a liquid may be brought into contact.
　本発明では、さらに弾性タッチロール押圧時のタッチロール線圧を９．８Ｎ／ｃｍ以上、１４７Ｎ／ｃｍ以下にすることが好ましい。線圧がこの範囲よりも小さいと、ダイラインを十分に解消することができなくなる。 In the present invention, it is preferable that the touch roll linear pressure when pressing the elastic touch roll is 9.8 N / cm or more and 147 N / cm or less. If the linear pressure is smaller than this range, the die line cannot be sufficiently eliminated.
　線圧とは、弾性タッチロールがフィルムを押圧する力を押圧時のフィルム幅で除した値である。線圧を上記の範囲にする方法は、特に限定はなく、例えば、エアーシリンダーや油圧シリンダーなどでロール両端を押圧することができる。 The linear pressure is a value obtained by dividing the force with which the elastic touch roll presses the film by the film width at the time of pressing. The method for setting the linear pressure within the above range is not particularly limited, and for example, both ends of the roll can be pressed with an air cylinder or a hydraulic cylinder.
　サポートロールにより弾性タッチロールを押圧することで、間接的にフィルムを押圧してもよい。 The film may be pressed indirectly by pressing the elastic touch roll with the support roll.
　タッチロールによってダイラインを良好に解消するためには、タッチロールがアクリルフィルムを挟圧するときのアクリルフィルムの粘度が適切な範囲であることが重要となる。 In order to satisfactorily eliminate the die line by the touch roll, it is important that the viscosity of the acrylic film when the touch roll sandwiches the acrylic film is in an appropriate range.
　また、セルロースエステルは温度による粘度の変化が比較的大きいことが知られている。 In addition, it is known that cellulose ester has a relatively large change in viscosity with temperature.
　フィルムのガラス転移温度をＴｇとしたとき、押出されたフィルムがタッチロールに挟圧される直前のタッチロール側フィルム表面温度Ｔｔを、Ｔｇ＜Ｔｔ＜Ｔｇ＋１１０℃とすることが好ましい。 When the glass transition temperature of the film is Tg, the touch roll side film surface temperature Tt immediately before the extruded film is clamped by the touch roll is preferably Tg <Tt <Tg + 110 ° C.
　即ち、タッチロールに挟圧される直前のフィルムの温度Ｔｔが上記の範囲にすると、フィルムを挟圧するときのフィルムの粘度を適切な範囲に設定することができ、ダイラインの矯正が可能となり、また、フィルム表面とロールが均一に接着し、ダイラインの矯正が可能となる。 That is, when the film temperature Tt immediately before being sandwiched between the touch rolls is within the above range, the viscosity of the film when sandwiching the film can be set to an appropriate range, and the die line can be corrected. The film surface and the roll are bonded uniformly, and the die line can be corrected.
　好ましくはＴｇ＋１０℃＜Ｔｔ＜Ｔｇ＋９０℃、さらに好ましくはＴｇ＋２０℃＜Ｔｔ＜Ｔｇ＋７０℃である。 Preferably, Tg + 10 ° C. <Tt <Tg + 90 ° C., and more preferably Tg + 20 ° C. <Tt <Tg + 70 ° C.
　押圧時のフィルム温度を上記範囲にする方法は特に限定はないが、例えば、ダイと冷却ロール間の距離を近づけて、ダイと冷却ロール間での冷却を抑制する方法やダイと冷却ロール間を断熱材で囲って保温したり、あるいは熱風や赤外線ヒーターやマイクロ波加熱等により加温したりする方法が挙げられる。 The method of setting the film temperature at the time of pressing in the above range is not particularly limited. For example, the distance between the die and the cooling roll is made closer, and the cooling between the die and the cooling roll is suppressed, or between the die and the cooling roll. Examples of the method include heat insulation by surrounding with a heat insulating material, or heating by hot air, an infrared heater, microwave heating, or the like.
　フィルム表面温度およびロール表面温度は非接触式の赤外温度計で測定できる。具体的には、非接触ハンディ温度計（ＩＴ２－８０、（株）キーエンス製）を用いてフィルムの幅手方向に１０箇所を被測定物から０．５ｍの距離で測定する。 Film surface temperature and roll surface temperature can be measured with a non-contact infrared thermometer. Specifically, using a non-contact handy thermometer (IT2-80, manufactured by Keyence Co., Ltd.), 10 points in the width direction of the film are measured at a distance of 0.5 m from the object to be measured.
　弾性タッチロール側フィルム表面温度Ｔｔは、搬送されているフィルムをタッチロールをはずした状態でタッチロール側から非接触式の赤外温度計で測定したフィルム表面温度のことをさす。 Elastic touch roll side film surface temperature Tt refers to the film surface temperature measured with a non-contact infrared thermometer from the touch roll side with the touch roll removed from the film being transported.
　《流延工程》
　本発明においては、流延ダイの開口部（リップ）から冷却ロールまでの部分を７０ｋＰａ以下に減圧させることにより、上記、ダイラインの矯正効果がより大きく発現する。 《Casting process》
In the present invention, the die line correction effect is more greatly manifested by reducing the pressure from the opening (lip) of the casting die to the cooling roll to 70 kPa or less.
　好ましくは減圧は５０～７０ｋＰａである。流延ダイの開口部（リップ）から冷却ロールまでの部分の圧力を７０ｋＰａ以下に保つ方法としては、特に制限はないが、流延ダイからロール周辺を耐圧部材で覆って減圧する方法などがある。 Preferably, the reduced pressure is 50 to 70 kPa. There is no particular limitation on the method for maintaining the pressure of the portion from the opening (lip) of the casting die to the cooling roll to 70 kPa or less, but there is a method of reducing the pressure by covering the periphery of the casting die with a pressure-resistant member. .
　このとき、吸引装置は、装置自体が昇華物の付着場所にならないようヒーターで加熱する等の処置を施すことが好ましい。本発明では、吸引圧が小さすぎると昇華物を効果的に吸引できないため、適当な吸引圧とする必要がある。 At this time, the suction device is preferably subjected to a treatment such as heating with a heater so that the device itself does not become a place where the sublimate adheres. In the present invention, if the suction pressure is too small, the sublimate cannot be sucked effectively, so it is necessary to set the suction pressure to an appropriate value.
　本発明では、セルロースエステルを含む溶融物をダイからフィルム状に押出し、ドロー比５以上３０以下として得られたフィルムを、弾性タッチロールで冷却ロールに押圧しながら搬送する。ドロー比とは、ダイのリップクリアランスを冷却ロール上で固化したフィルムの平均膜厚で除した値である。ドロー比をこの範囲とすることで、液晶表示装置で画像を表示したときに、明暗のスジや斑点状むらがなく、生産性の良好な偏光子保護フィルムが得られる。 In the present invention, a melt containing cellulose ester is extruded from a die into a film, and a film obtained with a draw ratio of 5 or more and 30 or less is conveyed while being pressed against a cooling roll by an elastic touch roll. The draw ratio is a value obtained by dividing the lip clearance of the die by the average film thickness of the film solidified on the cooling roll. By setting the draw ratio within this range, when an image is displayed on a liquid crystal display device, there is no bright and dark streak or uneven spot, and a polarizer protective film with good productivity can be obtained.
　ドロー比は、ダイリップクリアランスと冷却ロールの引き取り速度により調整できる。ダイリップクリアランスは、９００μｍ以上が好ましく、さらに１ｍｍ以上２ｍｍ以下が好ましい。大きすぎても、小さすぎても斑点状むらが改善されない場合がある。 The draw ratio can be adjusted by the die lip clearance and the cooling roll take-up speed. The die lip clearance is preferably 900 μm or more, more preferably 1 mm or more and 2 mm or less. Even if it is too large or too small, spotted unevenness may not be improved.
　冷却ロールと弾性タッチロールでフィルムをニップする際のタッチロール側のフィルム温度をフィルムのＴｇ以上Ｔｇ＋１１０℃以下にすることは、フィルム表面の写像性を調整するために好ましい。このような目的で使用する弾性体表面を有するロールは、公知のロールが使用できる。 It is preferable to adjust the film temperature on the touch roll side when the film is nipped between the cooling roll and the elastic touch roll to Tg of the film or more and Tg + 110 ° C. or less in order to adjust the image clarity of the film surface. A well-known roll can be used for the roll which has the elastic body surface used for such a purpose.
　冷却ロールからフィルムを剥離する際は、張力を制御してフィルムの変形を防止することが好ましい。 When peeling the film from the cooling roll, it is preferable to control the tension to prevent deformation of the film.
　《ロール清掃設備》
　本発明に係る製造装置には、ドラムおよびロールを清掃する装置を付加させることが好ましい。清掃装置については特に限定はないが、例えば、ブラシ・ロール、吸水ロール、粘着ロール、ふき取りロール等をニップする方式、清浄エアーを吹き掛けるエアーブロー方式、レーザーによる焼却装置、あるいはこれらの組み合わせなどがある。 《Roll cleaning equipment》
It is preferable to add a device for cleaning the drum and roll to the manufacturing apparatus according to the present invention. There are no particular restrictions on the cleaning device. For example, there are a method of niping a brush roll, a water absorbing roll, an adhesive roll, a wiping roll, an air blow method of blowing clean air, a laser incinerator, or a combination thereof. is there.
　清掃用ロールをニップする方式の場合、ベルト線速度とローラ線速度を変えると清掃効果が大きい。 ¡In the case of a system in which a cleaning roll is nipped, the cleaning effect is great if the belt linear velocity and roller linear velocity are changed.
　《延伸工程》
　本発明では、上記のようにして得られたフィルムは冷却ロールに接する工程を通過後、縦（フィルム搬送方向）、横（巾方向）の少なくとも一方向に１．１（１０％）～２．５（１５０％）倍延伸する。 << Extension process >>
In the present invention, the film obtained as described above passes through the step of coming into contact with the cooling roll, and then 1.1 (10%) to 2.1 in at least one direction of the length (film transport direction) and the width (width direction). Stretch 5 (150%) times.
　通常光学フィルムにおいては平面性を改善するため、レターデーションを調整するために延伸処理がされるが、本発明のフィルムでは延伸することによりケン化適性をより強固にすることができる。 Usually, in order to improve flatness in an optical film, a stretching treatment is performed to adjust retardation. However, in the film of the present invention, the saponification suitability can be further strengthened by stretching.
　その理由としては、延伸処理することによりフィルムの活性エネルギーの高い部分が表面から露出し、その部分がケン化適性を向上させていると推測している。 The reason is presumed that the stretched portion exposes the high active energy portion of the film from the surface, and the portion improves the saponification suitability.
　延伸する方法としては、公知のロール延伸機やテンターなどを用いることができる。延伸温度は、通常、フィルムを構成する樹脂のＴｇ～Ｔｇ＋５０℃、好ましくはＴｇ～Ｔｇ＋４０℃の温度範囲で行われる。 As a stretching method, a known roll stretching machine or tenter can be used. The stretching temperature is usually in the temperature range of Tg to Tg + 50 ° C., preferably Tg to Tg + 40 ° C. of the resin constituting the film.
　延伸は、幅手方向で制御された均一な温度分布下で行うことが好ましい。好ましくは±２℃以内、さらに好ましくは±１℃以内、特に好ましくは±０．５℃以内である。 The stretching is preferably performed under a uniform temperature distribution controlled in the width direction. The temperature is preferably within ± 2 ° C, more preferably within ± 1 ° C, and particularly preferably within ± 0.5 ° C.
　また延伸工程には公知の熱固定条件、冷却、緩和処理を行ってもよく、目的とするフィルムに要求される特性を有するように適宜調整することができる。 In the stretching step, known heat setting conditions, cooling, and relaxation treatment may be performed, and adjustment can be made as appropriate so as to have characteristics required for the target film.
　長手方向に収縮するには、例えば、巾延伸を一時クリップアウトさせて長手方向に弛緩させる、または横延伸機の隣り合うクリップの間隔を徐々に狭くすることによりフィルムを収縮させるという方法がある。 In order to shrink in the longitudinal direction, for example, there is a method in which the film is shrunk by temporarily clipping out the width stretching and relaxing in the longitudinal direction, or by gradually narrowing the interval between adjacent clips of the transverse stretching machine.
　後者の方法は一般の同時二軸延伸機を用いて、縦方向の隣り合うクリップの間隔を、例えばパンタグラフ方式やリニアドライブ方式でクリップ部分を駆動して滑らかに徐々に狭くする方法によって行うことができる。 The latter method can be performed by using a general simultaneous biaxial stretching machine, and by gradually and gradually narrowing the interval between adjacent clips in the longitudinal direction by driving the clip portion by, for example, a pantograph method or a linear drive method. it can.
　必要により任意の方向（斜め方向）の延伸と組み合わせてもよい。長手方向、巾手方向とも０．５％から１０％収縮させることでフィルムの寸法変化率を小さくすることができる。 If necessary, it may be combined with stretching in any direction (oblique direction). The dimensional change rate of the film can be reduced by shrinking 0.5% to 10% in both the longitudinal direction and the width direction.
　また、延伸によってフィルムの弾性率を上げることができるため、延伸は溶融製膜したフィルムの弾性率の低さを補う手段として有効である。 Also, since the elastic modulus of the film can be increased by stretching, the stretching is effective as a means for compensating for the low elastic modulus of the melt-formed film.
　延伸は、例えばフィルムの長手方向およびそれとフィルム面内で直交する方向、即ち幅方向に対して、逐次または同時に行うことができる。 Stretching can be performed sequentially or simultaneously, for example, in the longitudinal direction of the film and in the direction orthogonal to the longitudinal direction of the film, that is, in the width direction.
　互いに直行する二軸方向に延伸することにより、得られるフィルムの膜厚変動が減少できる。フィルムの膜厚変動が大き過ぎると位相差のムラとなり、液晶ディスプレイに用いたとき着色等のムラが問題となることがある。 The film thickness variation of the film obtained can be reduced by stretching in the biaxial directions perpendicular to each other. If the film thickness variation is too large, the retardation will be uneven, and unevenness such as coloring may be a problem when used in a liquid crystal display.
　フィルムの膜厚変動は、±３％であることが好ましく、±１％の範囲とすることがさらに好ましい。 The film thickness variation of the film is preferably ± 3%, and more preferably ± 1%.
　延伸後、フィルムの端部をスリッターにより製品となる幅にスリットして裁ち落とした後、エンボスリングおよびバックロールよりなるナール加工装置によりナール加工（エンボッシング加工）をフィルム両端部に施し、巻取り機によって巻き取ることにより、フィルム（元巻き）中の貼り付きや、すり傷の発生を防止する。ナール加工の方法は、凸凹のパターンを側面に有する金属リングを加熱や加圧により加工することができる。 After stretching, after slitting the edge of the film to a product width with a slitter, the film is subjected to knurling (embossing) on both ends of the film by a knurling device consisting of an embossing ring and a back roll, and a winder By taking up with, the sticking in a film (original winding) and generation | occurrence | production of an abrasion are prevented. The knurling method can process a metal ring having an uneven pattern on its side surface by heating or pressing.
　なお、スリッターにより切除したフィルムの両端部は、原料として再利用してもよい。 In addition, you may reuse the both ends of the film cut by the slitter as a raw material.
　次に、偏光子保護フィルムの巻取り工程は、円筒形巻きフィルムの外周面とこれの直前の移動式搬送ロールの外周面との間の最短距離を一定に保持しながらフィルムを巻取りロールに巻き取るものである。かつ巻取りロールの手前には、フィルムの表面電位を除去または低減する除電ブロア等の手段が設けられている。 Next, in the winding process of the polarizer protective film, the film is turned into a take-up roll while keeping the shortest distance between the outer peripheral face of the cylindrical roll film and the outer peripheral face of the movable transport roll immediately before this. It is to be wound up. In addition, a means such as a static elimination blower for removing or reducing the surface potential of the film is provided in front of the winding roll.
　本発明のフィルムの製造に係わる巻き取り機は一般的に使用されているものでよく、定テンション法、定トルク法、テーパーテンション法、内部応力一定のプログラムテンションコントロール法等の巻き取り方法で巻き取ることができる。なお、アクリルフィルムの巻取り時の初期巻取り張力が９０．２～３００．８Ｎ／ｍであることが好ましい。 The winder related to the production of the film of the present invention may be generally used, and it is wound by a winding method such as a constant tension method, a constant torque method, a taper tension method, or a program tension control method with a constant internal stress. Can be taken. The initial winding tension when winding the acrylic film is preferably 90.2 to 300.8 N / m.
　本発明の方法におけるフィルムの巻き取り工程では、温度２０～３０℃、湿度２０～６０％ＲＨの環境条件にて、フィルムを巻き取ることが好ましい。巻き取り工程における温度が２０～３０℃の範囲であれば、シワの発生がなく、アクリルフィルム巻品質劣化もない。また、フィルムの巻き取り工程における湿度が２０～６０％ＲＨであれば、吸湿によるフィルム巻品質劣化も削減され、巻品質に優れ、貼り付き故障もなく、搬送性の劣化もない。 In the film winding step in the method of the present invention, the film is preferably wound under environmental conditions of a temperature of 20 to 30 ° C. and a humidity of 20 to 60% RH. If the temperature in the winding process is in the range of 20 to 30 ° C., there will be no wrinkles and the acrylic film winding quality will not deteriorate. Further, if the humidity in the film winding process is 20 to 60% RH, the film winding quality deterioration due to moisture absorption is reduced, the winding quality is excellent, there is no sticking failure, and there is no deterioration in transportability.
　フィルムをロール状に巻き取る際の巻きコアとしては、円筒上のコアであれはどのような材質のものであってもよいが、好ましくは中空プラスチックコアである。プラスチック材料としては加熱処理温度にも耐える耐熱性プラスチックであればどのようなものであってもよく、フェノール樹脂、キシレン樹脂、メラミン樹脂、ポリエステル樹脂、エポキシ樹脂等の樹脂が挙げられる。 The winding core for winding the film into a roll may be any material as long as it is a cylindrical core, but is preferably a hollow plastic core. The plastic material may be any heat-resistant plastic that can withstand the heat treatment temperature, and examples thereof include phenol resins, xylene resins, melamine resins, polyester resins, and epoxy resins.
　またガラス繊維等の充填材により強化した熱硬化性樹脂が好ましい。例えば、中空プラスチックコア：ＦＲＰ製の外径６インチ（以下、１インチは２．５４ｃｍである。）、内径５インチの巻きコアが用いられる。 Further, a thermosetting resin reinforced with a filler such as glass fiber is preferable. For example, a hollow plastic core: a wound core made of FRP having an outer diameter of 6 inches (hereinafter, 1 inch is 2.54 cm) and an inner diameter of 5 inches is used.
　本発明の偏光子保護フィルムの製造において、ロール長さは、生産性と運搬性を考慮すると、長さは１０～７５００ｍが好ましく、より好ましくは５０～５５００ｍである。 In the production of the polarizer protective film of the present invention, the roll length is preferably 10 to 7500 m, more preferably 50 to 5500 m in consideration of productivity and transportability.
　このときの偏光子保護フィルムの幅は、偏光子の幅や製造ラインに適した幅を選択することができるが、０．５～４．０ｍ、好ましくは１．０～３．０ｍの幅でフィルムを製造してロール状に巻き取ることが好ましい。 The width of the polarizer protective film at this time can be selected from the width of the polarizer and the width suitable for the production line, but it is 0.5 to 4.0 m, preferably 1.0 to 3.0 m. It is preferable to manufacture a film and to wind up in roll shape.
　本発明におけるフィルムの透明性を判断する指標としては、ヘイズ値（濁度）を用いる。特に屋外で用いられる液晶表示装置においては、明るい場所でも十分な輝度や高いコントラストが得られることが求められるため、ヘイズ値は０．５％以下であることが必要とされ、０．３５％以下であることがさらに好ましい。 Haze value (turbidity) is used as an index for judging the transparency of the film in the present invention. In particular, liquid crystal display devices used outdoors are required to have sufficient brightness and high contrast even in a bright place. Therefore, the haze value is required to be 0.5% or less, and 0.35% or less. More preferably.
　本発明のフィルムは、その全光線透過率が９０％以上であることが好ましく、より好ましくは９２％以上である。かかる全光線透過率にて表される優れた透明性を達成するには、可視光を吸収する添加剤や共重合成分を導入しないようにすることや、ポリマー中の異物を高精度濾過により除去し、フィルム内部の光の拡散や吸収を低減させることが有効である。 The film of the present invention preferably has a total light transmittance of 90% or more, more preferably 92% or more. In order to achieve excellent transparency expressed by such total light transmittance, it is necessary not to introduce additives and copolymerization components that absorb visible light, or to remove foreign substances in the polymer by high-precision filtration. It is effective to reduce the diffusion and absorption of light inside the film.
　また、製膜時のフィルム接触部（冷却ロール、カレンダーロール、ドラム、ベルト、溶液製膜における塗布基材、搬送ロールなど）の表面粗さを小さくしてフィルム表面の表面粗さを小さくすることや、アクリル樹脂の屈折率を小さくすることによりフィルム表面の光の拡散や反射を低減させることが有効である。 Also, reduce the surface roughness of the film surface by reducing the surface roughness of the film contact part (cooling roll, calender roll, drum, belt, coating substrate in solution casting, transport roll, etc.) during film formation. It is also effective to reduce the diffusion and reflection of light on the film surface by reducing the refractive index of the acrylic resin.
　本発明の偏光子保護フィルムの膜厚に特に制限はないが、後述する偏光子保護フィルムに使用する場合は２０～２００μｍであることが好ましく、２５～１００μｍであることがより好ましく、３０～６５μｍであることが特に好ましい。 The film thickness of the polarizer protective film of the present invention is not particularly limited, but when used for the polarizer protective film described later, it is preferably 20 to 200 μm, more preferably 25 to 100 μm, and 30 to 65 μm. It is particularly preferred that
　本発明の偏光子保護フィルムは、溶融流延製膜方法によって作製することから、ロール状フィルムとして巻き取った時点で、含有している溶媒量が０．０１質量％以下である。含有溶媒量は、下記の方法によって測定することができる。 Since the polarizer protective film of the present invention is produced by the melt casting film forming method, the amount of the solvent contained is 0.01% by mass or less when wound as a roll film. The amount of the solvent can be measured by the following method.
　各試料を２０ｍｌの密閉ガラス容器に入れ、下記ヘッドスペース加熱条件にて処理したあと、下記ガスクロマトグラフィーにて予め使用した溶媒について検量線を作成し測定を行った。含有溶媒量は、アクリルフィルムの全体の質量に対する質量部で表した。
機器：ＨＰ社　５８９０ＳＥＲＩＥＳ　II
カラム：Ｊ＆Ｗ社　ＤＢ－ＷＡＸ（内径０．３２ｍｍ、長さ３０ｍ）
検出：ＦＩＤ
ＧＣ昇温条件：４０℃で５分間保持したあと、８０℃／分で１００℃まで昇温
ヘッドスペース加熱条件：１２０℃で２０ｍｉｎ
　（溶液流延製膜方法）
　ついで、溶液流延製膜法について述べる。 Each sample was placed in a 20 ml sealed glass container, treated under the following headspace heating conditions, and then a calibration curve was prepared and measured for the solvent used in advance by the following gas chromatography. The amount of solvent contained was expressed in parts by mass relative to the total mass of the acrylic film.
Equipment: HP 5890SERIES II
Column: J-W DB-WAX (inner diameter 0.32 mm, length 30 m)
Detection: FID
GC temperature rising condition: held at 40 ° C. for 5 minutes, then heated to 80 ° C./min to 100 ° C. Headspace heating condition: 120 ° C. for 20 min
(Solution casting film forming method)
Next, the solution casting film forming method will be described.
　（有機溶媒）
　本発明のフィルムを溶液流延法で製造する場合のドープを形成するのに有用な有機溶媒は、アクリル樹脂（Ａ）、セルロースエステル樹脂（Ｂ）、場合によってアクリル粒子およびその他の添加剤を同時に溶解するものであれば制限なく用いることができる。 (Organic solvent)
The organic solvent useful for forming a dope when the film of the present invention is produced by the solution casting method is an acrylic resin (A), a cellulose ester resin (B), and optionally acrylic particles and other additives at the same time. Any material that can be dissolved can be used without limitation.
　例えば、塩素系有機溶媒としては、塩化メチレン、非塩素系有機溶媒としては、酢酸メチル、酢酸エチル、酢酸アミル、アセトン、テトラヒドロフラン、１，３－ジオキソラン、１，４－ジオキサン、シクロヘキサノン、ギ酸エチル、２，２，２－トリフルオロエタノール、２，２，３，３－ヘキサフルオロ－１－プロパノール、１，３－ジフルオロ－２－プロパノール、１，１，１，３，３，３－ヘキサフルオロ－２－メチル－２－プロパノール、１，１，１，３，３，３－ヘキサフルオロ－２－プロパノール、２，２，３，３，３－ペンタフルオロ－１－プロパノール、ニトロエタン等を挙げることができ、塩化メチレン、酢酸メチル、酢酸エチル、アセトンを好ましく使用し得る。 For example, as a chlorinated organic solvent, methylene chloride, as a non-chlorinated organic solvent, methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro- 2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, nitroethane, etc. Methylene chloride, methyl acetate, ethyl acetate and acetone can be preferably used.
　ドープには、上記有機溶媒の他に、１～４０質量％の炭素原子数１～４の直鎖または分岐鎖状の脂肪族アルコールを含有させることが好ましい。ドープ中のアルコールの比率が高くなるとウェブがゲル化し、金属支持体からの剥離が容易になり、また、アルコールの割合が少ない時は非塩素系有機溶媒系でのアクリル樹脂（Ａ）、セルロースエステル樹脂（Ｂ）の溶解を促進する役割もある。 In addition to the organic solvent, the dope preferably contains 1 to 40% by mass of a linear or branched aliphatic alcohol having 1 to 4 carbon atoms. When the ratio of alcohol in the dope increases, the web gels and peeling from the metal support becomes easy. When the ratio of alcohol is small, acrylic resin (A) and cellulose ester in non-chlorine organic solvent system. There is also a role of promoting dissolution of the resin (B).
　特に、メチレンクロライド、および炭素数１～４の直鎖または分岐鎖状の脂肪族アルコールを含有する溶媒に、アクリル樹脂（Ａ）と、セルロースエステル樹脂（Ｂ）と、場合によってアクリル粒子の３種を、少なくとも計１５～４５質量％溶解させたドープ組成物であることが好ましい。 In particular, a solvent containing methylene chloride and a linear or branched aliphatic alcohol having 1 to 4 carbon atoms includes an acrylic resin (A), a cellulose ester resin (B), and, in some cases, three kinds of acrylic particles. Is preferably a dope composition in which at least 15 to 45% by mass is dissolved.
　炭素原子数１～４の直鎖または分岐鎖状の脂肪族アルコールとしては、メタノール、エタノール、ｎ－プロパノール、ｉｓｏ－プロパノール、ｎ－ブタノール、ｓｅｃ－ブタノール、ｔｅｒｔ－ブタノールを挙げることができる。これらの内ドープの安定性、沸点も比較的低く、乾燥性もよいこと等からエタノールが好ましい。 Examples of the linear or branched aliphatic alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, and tert-butanol. Ethanol is preferred because of the stability of these dopes, the relatively low boiling point, and good drying properties.
　１）溶解工程
　アクリル樹脂（Ａ）、セルロースエステル樹脂（Ｂ）に対する良溶媒を主とする有機溶媒に、溶解釜中で該アクリル樹脂（Ａ）、セルロースエステル樹脂（Ｂ）、場合によってアクリル粒子、その他の添加剤を攪拌しながら溶解しドープを形成する工程、あるいは該アクリル樹脂（Ａ）、セルロースエステル樹脂（Ｂ）溶液に、場合によってアクリル粒子溶液、その他の添加剤溶液を混合して主溶解液であるドープを形成する工程である。 1) Dissolution step In an organic solvent mainly composed of a good solvent for the acrylic resin (A) and the cellulose ester resin (B), the acrylic resin (A), the cellulose ester resin (B), and optionally acrylic particles in a dissolution vessel, The step of dissolving other additives while stirring to form a dope, or the acrylic resin (A) and cellulose ester resin (B) solutions are mixed with acrylic particle solutions and other additive solutions as the main solution. This is a step of forming a dope that is a liquid.
　アクリル樹脂（Ａ）、セルロースエステル樹脂（Ｂ）の溶解には、常圧で行う方法、主溶媒の沸点以下で行う方法、主溶媒の沸点以上で加圧して行う方法、特開平９－９５５４４号公報、特開平９－９５５５７号公報、または特開平９－９５５３８号公報に記載の如き冷却溶解法で行う方法、特開平１１－２１３７９号公報に記載の如き高圧で行う方法等種々の溶解方法を用いることができるが、特に主溶媒の沸点以上で加圧して行う方法が好ましい。 For dissolving the acrylic resin (A) and the cellulose ester resin (B), a method carried out at normal pressure, a method carried out below the boiling point of the main solvent, a method carried out under pressure above the boiling point of the main solvent, JP-A-9-95544 Various dissolution methods such as a method of performing a cooling dissolution method as described in JP-A-9-95557 or JP-A-9-95538, a method of performing at a high pressure as described in JP-A-11-21379, and the like. Although it can be used, a method in which pressure is applied at a temperature equal to or higher than the boiling point of the main solvent is particularly preferable.
　ドープ中のアクリル樹脂（Ａ）と、セルロースエステル樹脂（Ｂ）は、計１５～４５質量％の範囲であることが好ましい。溶解中または後のドープに添加剤を加えて溶解および分散した後、濾材で濾過し、脱泡して送液ポンプで次工程に送る。 The acrylic resin (A) and cellulose ester resin (B) in the dope are preferably in the range of 15 to 45% by mass in total. After the additive is added to the dope during or after dissolution, the dope is dissolved and dispersed, filtered through a filter medium, defoamed, and sent to the next step with a liquid feed pump.
　濾過は捕集粒子径０．５～５μｍで、かつ濾水時間１０～２５ｓｅｃ／１００ｍｌの濾材を用いることが好ましい。 For filtration, it is preferable to use a filter medium having a collected particle diameter of 0.5 to 5 μm and a drainage time of 10 to 25 sec / 100 ml.
　この方法では、粒子分散時に残存する凝集物や主ドープ添加時発生する凝集物を、捕集粒子径０．５～５μｍで、かつ濾水時間１０～２５ｓｅｃ／１００ｍｌの濾材を用いることで凝集物だけ除去できる。主ドープでは粒子の濃度も添加液に比べ十分に薄いため、濾過時に凝集物同士がくっついて急激な濾圧上昇することもない。 In this method, the aggregate remaining at the time of particle dispersion and the aggregate generated when the main dope is added are aggregated by using a filter medium having a collected particle diameter of 0.5 to 5 μm and a drainage time of 10 to 25 sec / 100 ml. Can only be removed. In the main dope, the concentration of particles is sufficiently thinner than that of the additive solution, so that the aggregates do not stick together during filtration and the filtration pressure does not increase suddenly.
　多くの場合、主ドープには返材が１０～５０質量％程度含まれることがある。返材にはアクリル粒子が含まれることがある、その場合には返材の添加量に合わせてアクリル粒子添加液の添加量をコントロールすることが好ましい。 In many cases, the main dope may contain about 10 to 50% by weight of recycled material. The return material may contain acrylic particles. In that case, it is preferable to control the addition amount of the acrylic particle addition liquid in accordance with the addition amount of the return material.
　アクリル粒子を含有する添加液には、アクリル粒子を０．５～１０質量％含有していることが好ましく、１～１０質量％含有していることがさらに好ましく、１～５質量％含有していることが最も好ましい。 The additive liquid containing acrylic particles preferably contains 0.5 to 10% by mass of acrylic particles, more preferably 1 to 10% by mass, and more preferably 1 to 5% by mass. Most preferably.
　上記範囲内であれば、添加液は低粘度で取り扱い易く、主ドープへの添加が容易であるため好ましい。 If it is within the above range, the additive solution is preferable because it has a low viscosity and is easy to handle and can be easily added to the main dope.
　返材とは、フィルムを細かく粉砕した物で、フィルムを製膜するときに発生する、フィルムの両サイド部分を切り落とした物や、擦り傷などでスペックアウトしたフィルム原反が使用される。 The return material is a product obtained by finely pulverizing a film, and is produced by forming a film by cutting off both sides of the film, or by using an original film that has been speculated out of scratches.
　また、あらかじめアクリル樹脂、セルロースエステル樹脂、場合によってアクリル粒子を混練してペレット化したものも、好ましく用いることができる。 In addition, acrylic resin, cellulose ester resin, and in some cases, acrylic particles kneaded into pellets can be preferably used.
　２）流延工程
　ドープを、送液ポンプ（例えば、加圧型定量ギヤポンプ）を通して加圧ダイに送液し、無限に移送する無端の金属ベルト、例えばステンレスベルト、あるいは回転する金属ドラム等の金属支持体上の流延位置に、加圧ダイスリットからドープを流延する工程である。 2) Casting process An endless metal belt, such as a stainless steel belt or a rotating metal drum, which supports the dope is fed to a pressure die through a liquid feed pump (for example, a pressurized metering gear pump) and supported infinitely. This is a step of casting a dope from a pressure die slit to a casting position on the body.
　ダイの口金部分のスリット形状を調整でき、膜厚を均一にし易い加圧ダイが好ましい。加圧ダイには、コートハンガーダイやＴダイ等があり、いずれも好ましく用いられる。金属支持体の表面は鏡面となっている。製膜速度を上げるために加圧ダイを金属支持体上に２基以上設け、ドープ量を分割して重層してもよい。あるいは複数のドープを同時に流延する共流延法によって積層構造のフィルムを得ることも好ましい。 ¡Pressure dies that can adjust the slit shape of the die base and make the film thickness uniform are preferred. Examples of the pressure die include a coat hanger die and a T die, and any of them is preferably used. The surface of the metal support is a mirror surface. In order to increase the film forming speed, two or more pressure dies may be provided on the metal support, and the dope amount may be divided and stacked. Or it is also preferable to obtain the film of a laminated structure by the co-casting method which casts several dope simultaneously.
　３）溶媒蒸発工程
　ウェブ（流延用支持体上にドープを流延し、形成されたドープ膜をウェブと呼ぶ）を流延用支持体上で加熱し、溶媒を蒸発させる工程である。 3) Solvent evaporation step In this step, the web (the dope is cast on the casting support and the formed dope film is called a web) is heated on the casting support to evaporate the solvent.
　溶媒を蒸発させるには、ウェブ側から風を吹かせる方法および／または支持体の裏面から液体により伝熱させる方法、輻射熱により表裏から伝熱する方法等があるが、裏面液体伝熱方法が乾燥効率が良く好ましい。又、それらを組み合わせる方法も好ましく用いられる。流延後の支持体上のウェブを４０～１００℃の雰囲気下、支持体上で乾燥させることが好ましい。４０～１００℃の雰囲気下に維持するには、この温度の温風をウェブ上面に当てるか赤外線等の手段により加熱することが好ましい。 To evaporate the solvent, there are a method of blowing air from the web side and / or a method of transferring heat from the back side of the support by a liquid, a method of transferring heat from the front and back by radiant heat, and the like. High efficiency and preferable. A method of combining them is also preferably used. The web on the support after casting is preferably dried on the support in an atmosphere of 40 to 100 ° C. In order to maintain the atmosphere at 40 to 100 ° C., it is preferable to apply hot air at this temperature to the upper surface of the web or heat by means such as infrared rays.
　面品質、透湿性、剥離性の観点から、３０～１２０秒以内で該ウェブを支持体から剥離することが好ましい。 From the viewpoint of surface quality, moisture permeability, and peelability, it is preferable to peel the web from the support within 30 to 120 seconds.
　４）剥離工程
　金属支持体上で溶媒が蒸発したウェブを、剥離位置で剥離する工程である。剥離されたウェブは次工程に送られる。 4) Peeling process It is the process of peeling the web which the solvent evaporated on the metal support body in a peeling position. The peeled web is sent to the next process.
　金属支持体上の剥離位置における温度は好ましくは１０～４０℃であり、さらに好ましくは１１～３０℃である。 The temperature at the peeling position on the metal support is preferably 10 to 40 ° C, more preferably 11 to 30 ° C.
　なお、剥離する時点での金属支持体上でのウェブの剥離時残留溶媒量は、乾燥の条件の強弱、金属支持体の長さ等により５０～１２０質量％の範囲で剥離することが好ましいが、残留溶媒量がより多い時点で剥離する場合、ウェブが柔らか過ぎると剥離時平面性を損ね、剥離張力によるツレや縦スジが発生し易いため、経済速度と品質との兼ね合いで剥離時の残留溶媒量が決められる。 The amount of residual solvent at the time of peeling of the web on the metal support at the time of peeling is preferably 50 to 120% by mass depending on the strength of drying conditions, the length of the metal support, and the like. If the web is peeled off at a time when the amount of residual solvent is larger, if the web is too soft, the flatness at the time of peeling will be lost, and slippage and vertical stripes are likely to occur due to the peeling tension. The amount of solvent is determined.
　ウェブの残留溶媒量は下記式で定義される。 The amount of residual solvent in the web is defined by the following formula.
　残留溶媒量（％）＝（ウェブの加熱処理前質量－ウェブの加熱処理後質量）／（ウェブの加熱処理後質量）×１００
　なお、残留溶媒量を測定する際の加熱処理とは、１１５℃で１時間の加熱処理を行うことを表す。 Residual solvent amount (%) = (mass before web heat treatment−mass after web heat treatment) / (mass after web heat treatment) × 100
Note that the heat treatment for measuring the residual solvent amount represents performing heat treatment at 115 ° C. for 1 hour.
　金属支持体とフィルムを剥離する際の剥離張力は、通常、１９６～２４５Ｎ／ｍであるが、剥離の際に皺が入り易い場合、１９０Ｎ／ｍ以下の張力で剥離することが好ましく、さらには、剥離できる最低張力～１６６．６Ｎ／ｍ、次いで、最低張力～１３７．２Ｎ／ｍで剥離することが好ましいが、特に好ましくは最低張力～１００Ｎ／ｍで剥離することである。 The peeling tension at the time of peeling the metal support and the film is usually 196 to 245 N / m. However, if wrinkles easily occur at the time of peeling, it is preferable to peel with a tension of 190 N / m or less. It is preferable to peel at a minimum tension of ˜166.6 N / m, and then peel at a minimum tension of ˜137.2 N / m, and particularly preferable to peel at a minimum tension of ˜100 N / m.
　本発明においては、該金属支持体上の剥離位置における温度を－５０～４０℃とするのが好ましく、１０～４０℃がより好ましく、１５～３０℃とするのが最も好ましい。 In the present invention, the temperature at the peeling position on the metal support is preferably −50 to 40 ° C., more preferably 10 to 40 ° C., and most preferably 15 to 30 ° C.
　５）乾燥および延伸工程
　剥離後、ウェブを乾燥装置内に複数配置したロールに交互に通して搬送する乾燥装置、またはクリップでウェブの両端をクリップして搬送するテンター延伸装置を用いて、ウェブを乾燥する。 5) Drying and stretching step After peeling, use a drying device that alternately passes the web through rolls arranged in the drying device, or a tenter stretching device that clips and transports both ends of the web with clips. dry.
　乾燥手段はウェブの両面に熱風を吹かせるのが一般的であるが、風の代わりにマイクロウェーブを当てて加熱する手段もある。余り急激な乾燥は出来上がりのフィルムの平面性を損ね易い。高温による乾燥は残留溶媒が８質量％以下くらいから行うのがよい。全体を通し、乾燥は概ね４０～２５０℃で行われる。特に４０～１６０℃で乾燥させることが好ましい。 The drying means is generally to blow hot air on both sides of the web, but there is also a means to heat by applying microwaves instead of wind. Too rapid drying tends to impair the flatness of the finished film. Drying at a high temperature is preferably performed from about 8% by mass or less of residual solvent. Throughout, drying is generally performed at 40-250 ° C. In particular, drying at 40 to 160 ° C. is preferable.
　テンター延伸装置を用いる場合は、テンターの左右把持手段によってフィルムの把持長（把持開始から把持終了までの距離）を左右で独立に制御できる装置を用いることが好ましい。また、テンター工程において、平面性を改善するため意図的に異なる温度を持つ区画を作ることも好ましい。 When using a tenter stretching apparatus, it is preferable to use an apparatus that can independently control the film gripping length (distance from the start of gripping to the end of gripping) left and right by the left and right gripping means of the tenter. In the tenter process, it is also preferable to intentionally create sections having different temperatures in order to improve planarity.
　また、異なる温度区画の間にそれぞれの区画が干渉を起こさないように、ニュートラルゾーンを設けることも好ましい。 It is also preferable to provide a neutral zone between different temperature zones so that each zone does not cause interference.
　延伸処理は、前記溶融流延製膜方法と同じ延伸処理をすることが好ましい。テンターで行う場合のウェブの残留溶媒量は、テンター開始時に２０～１００質量％であるのが好ましく、かつウェブの残留溶媒量が１０質量％以下になる迄テンターを掛けながら乾燥を行うことが好ましく、さらに好ましくは５質量％以下である。 The stretching treatment is preferably performed in the same manner as the melt casting film forming method. When the tenter is used, the amount of residual solvent in the web is preferably 20 to 100% by mass at the start of the tenter, and drying is preferably performed while applying the tenter until the amount of residual solvent in the web is 10% by mass or less. More preferably, it is 5% by mass or less.
　テンターを行う場合の乾燥温度は、３０～１６０℃が好ましく、５０～１５０℃がさらに好ましく、７０～１４０℃が最も好ましい。 When performing the tenter, the drying temperature is preferably 30 to 160 ° C., more preferably 50 to 150 ° C., and most preferably 70 to 140 ° C.
　テンター工程において、雰囲気の幅手方向の温度分布が少ないことが、フィルムの均一性を高める観点から好ましく、テンター工程での幅手方向の温度分布は、±５℃以内が好ましく、±２℃以内がより好ましく、±１℃以内が最も好ましい。 In the tenter process, it is preferable that the temperature distribution in the width direction of the atmosphere is small from the viewpoint of improving the uniformity of the film. The temperature distribution in the width direction in the tenter process is preferably within ± 5 ° C, and within ± 2 ° C. Is more preferable, and within ± 1 ° C. is most preferable.
　６）巻き取り工程
　ウェブ中の残留溶媒量が２質量％以下となってからフィルムとして巻き取り機３７により巻き取る工程であり、残留溶媒量を０．４質量％以下にすることにより寸法安定性の良好なフィルムを得ることができる。特に０．００～０．１０質量％で巻き取ることが好ましい。 6) Winding process This is a process in which the amount of residual solvent in the web becomes 2% by mass or less, and is taken up by the winder 37 as a film, and the dimensional stability is achieved by setting the residual solvent amount to 0.4% by mass or less. Can be obtained. It is particularly preferable to wind up at 0.00 to 0.10% by mass.
　巻き取り方法は、一般に使用されているものを用いればよく、定トルク法、定テンション法、テーパーテンション法、内部応力一定のプログラムテンションコントロール法等があり、それらを使いわければよい。 As a winding method, a generally used one may be used, and there are a constant torque method, a constant tension method, a taper tension method, a program tension control method with a constant internal stress, etc., and these may be used properly.
　本発明のフィルムは、上記のような物性を満たしていれば、大型の液晶表示装置や屋外用途の液晶表示装置用の偏光子保護フィルムとして特に好ましく用いることができる。 The film of the present invention can be particularly preferably used as a polarizer protective film for a large-sized liquid crystal display device or a liquid crystal display device for outdoor use as long as the above physical properties are satisfied.
　＜偏光板の製造方法＞
　本発明のフィルムを偏光子保護フィルムとして用いる場合、偏光板は一般的なセルロースエステルを偏光子保護フィルムとする方法で作製することができる。すなわち、本発明の偏光子保護フィルムをケン化処理し、その後偏光子の貼合には、水性接着剤を使用することができる。 <Production method of polarizing plate>
When using the film of this invention as a polarizer protective film, a polarizing plate can be produced by the method which uses a general cellulose ester as a polarizer protective film. That is, a water-based adhesive can be used for saponifying the polarizer protective film of the present invention and then bonding the polarizer.
　ケン化処理は、基準条件としては以下の条件に近似の条件で行われるのが好ましい。 The saponification treatment is preferably performed under conditions approximate to the following conditions as reference conditions.
　　ケン化工程　　２．０Ｍ－ＮａＯＨ　４５℃　　９０秒
　　水洗工程　　　水　　　　　　　　　３０℃　　４５秒
　　中和工程　　　１０質量部ＨＣｌ　　３０℃　　４５秒
　　水洗工程　　　水　　　　　　　　　３０℃　　４５秒
　ケン化処理後、水洗、中和、水洗の順に行い、次いで８０℃で乾燥を行う。 Saponification step 2.0M-NaOH 45 ° C 90 seconds Water washing step Water 30 ° C 45 seconds Neutralization step 10 parts HCl 30 ° C 45 seconds Water washing step Water 30 ° C 45 seconds After saponification treatment, water washing, neutralization, water washing in this order Followed by drying at 80 ° C.
　但し、本発明ではケン化処理の迅速化を目的に下記の条件に近似の条件を好ましく用いることができる。 However, in the present invention, conditions approximate to the following conditions can be preferably used for the purpose of speeding up the saponification treatment.
　　ケン化工程　　１．５Ｍ－ＮａＯＨ　５５℃　　４０秒
　　水洗工程　　　水　　　　　　　　　４０℃　　２０秒
　　中和工程　　　１０質量部ＨＣｌ　　４０℃　　２０秒
　　水洗工程　　　水　　　　　　　　　４０℃　　２０秒
　ケン化処理後、水洗、中和、水洗の順に行い、次いで９０℃で乾燥を行う。 Saponification step 1.5M-NaOH 55 ° C 40 seconds Water washing step Water 40 ° C 20 seconds Neutralization step 10 parts HCl 40 ° C 20 seconds Water washing step Water 40 ° C 20 seconds After saponification treatment, water washing, neutralization, water washing in this order Followed by drying at 90 ° C.
　ケン化処理は延伸してから３６０時間以内にすることが好ましい。このケン化処理後、水性接着剤によって偏光子を貼合する。 The saponification treatment is preferably performed within 360 hours after stretching. After this saponification treatment, a polarizer is bonded with an aqueous adhesive.
　水性接着剤とは、溶媒の５０質量％以上が水である接着剤をいい、ポリビニルアルコール系水性接着剤、ゼラチン接着剤、ビニル系ラテックス接着剤、水系ポリエステル等を例示できるが、中でもポリビニルアルコール系水性接着剤であることが好ましい。 The water-based adhesive refers to an adhesive in which 50% by mass or more of the solvent is water, and examples thereof include polyvinyl alcohol-based aqueous adhesives, gelatin adhesives, vinyl-based latex adhesives, and water-based polyesters. A water-based adhesive is preferred.
　これらを通常、０．５～３０質量％の固形分に調製して用いることが好ましい。特にセルロースエステルを偏光子保護フィルムと使用した場合と同一の接着剤であることが好ましい。 These are usually preferably prepared to a solid content of 0.5 to 30% by mass. In particular, the same adhesive as that when cellulose ester is used with the polarizer protective film is preferable.
　もう一方の面には本発明の偏光子保護フィルムを用いても、別の偏光子保護フィルムを用いてもよい。例えば、市販のセルロースエステルフィルム（例えば、コニカミノルタタック　ＫＣ８ＵＸ、ＫＣ４ＵＸ、ＫＣ５ＵＸ、ＫＣ８ＵＹ、ＫＣ４ＵＹ、ＫＣ１２ＵＲ、ＫＣ８ＵＣＲ－３、ＫＣ８ＵＣＲ－４、ＫＣ８ＵＣＲ－５、ＫＣ８ＵＥ、ＫＣ４ＵＥ、ＫＣ４ＦＲ－３、ＫＣ４ＦＲ－４、ＫＣ４ＨＲ－１、ＫＣ８ＵＹ－ＨＡ、ＫＣ８ＵＸ－ＲＨＡ、以上コニカミノルタオプト（株）製）等が好ましく用いられる。 On the other side, the polarizer protective film of the present invention may be used, or another polarizer protective film may be used. For example, a commercially available cellulose ester film (for example, Konica Minoltack KC8UX, KC4UX, KC5UX, KC8UY, KC4UY, KC12UR, KC8UCR-3, KC8UCR-4, KC8UCR-5, KC8UE, KC4FR-4, KC4FR-3, KC4FR-3, KC4FR-4 -1, KC8UY-HA, KC8UX-RHA, manufactured by Konica Minolta Opto Co., Ltd.) and the like are preferably used.
　偏光板の主たる構成要素である偏光子とは、一定方向の偏波面の光だけを通す素子であり、現在知られている代表的な偏光子は、ポリビニルアルコール系偏光フィルムで、これはポリビニルアルコール系フィルムにヨウ素を染色させたものと二色性染料を染色させたものがある。 A polarizer, which is a main component of a polarizing plate, is an element that allows only light of a plane of polarization in a certain direction to pass. A typical polarizer currently known is a polyvinyl alcohol-based polarizing film, which is polyvinyl alcohol. There are one in which iodine is dyed on a system film and one in which dichroic dye is dyed.
　偏光子は、ポリビニルアルコール水溶液を製膜し、これを一軸延伸させて染色するか、染色した後一軸延伸してから、ホウ素化合物などで耐久性処理を行ったものが用いられている。 For the polarizer, a polyvinyl alcohol aqueous solution is formed into a film and dyed by uniaxial stretching or dyed or uniaxially stretched and then subjected to a durability treatment with a boron compound or the like.
　〔液晶表示装置〕
　本発明のフィルムを貼合した偏光板を液晶表示装置に組み込むことによって、種々の視認性に優れた液晶表示装置を作製することができるが、特に大型の液晶表示装置やデジタルサイネージ等の屋外用途の液晶表示装置に好ましく用いられる。本発明に係る偏光板は、前記粘着層等を介して液晶セルに貼合する。 [Liquid Crystal Display]
By incorporating the polarizing plate bonded with the film of the present invention into a liquid crystal display device, it is possible to produce various liquid crystal display devices with excellent visibility, but particularly for outdoor use such as large liquid crystal display devices and digital signage. The liquid crystal display device is preferably used. The polarizing plate according to the present invention is bonded to a liquid crystal cell via the adhesive layer or the like.
　本発明に係る偏光板は反射型、透過型、半透過型ＬＣＤまたはＴＮ型、ＳＴＮ型、ＯＣＢ型、ＨＡＮ型、ＶＡ型（ＰＶＡ型、ＭＶＡ型）、ＩＰＳ型（ＦＦＳ方式も含む）等の各種駆動方式のＬＣＤで好ましく用いられる。特に画面が３０型以上、特に３０型～５４型の大画面の表示装置では、画面周辺部での白抜け等もなく、その効果が長期間維持される。 The polarizing plate according to the present invention includes a reflective type, a transmissive type, a transflective type LCD or a TN type, an STN type, an OCB type, a HAN type, a VA type (PVA type, MVA type), an IPS type (including an FFS type), and the like. It is preferably used in various drive LCDs. In particular, in a large-screen display device having a screen of 30 or more, especially 30 to 54, there is no white spot at the periphery of the screen and the effect is maintained for a long time.
　以下に実施例を挙げて本発明を具体的に説明するが、本発明はこれらに限定されるものではない。 Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.
　実施例１
　＜アクリル粒子ＡＣ１の調製＞
　内容積６０リットルの還流冷却器付反応器に、イオン交換水３８．２リットル、ジオクチルスルホコハク酸ナトリウム１１１．６ｇを投入し、２５０ｒｐｍの回転数で攪拌しながら、窒素雰囲気下７５℃に昇温し、酸素の影響が事実上無い状態にした。ＡＰＳ０．３６ｇを投入し、５分間攪拌後にＭＭＡ１６５７ｇ、ＢＡ２１．６ｇ、およびＡＬＭＡ１．６８ｇからなる単量体混合物を一括添加し、発熱ピークの検出後さらに２０分間保持して最内硬質層の重合を完結させた。 Example 1
<Preparation of acrylic particles AC1>
A reactor with a reflux condenser with an internal volume of 60 liters was charged with 38.2 liters of ion-exchanged water and 111.6 g of sodium dioctylsulfosuccinate, and the temperature was raised to 75 ° C. in a nitrogen atmosphere while stirring at 250 rpm. The effect of oxygen was virtually eliminated. 0.36 g of APS was added, and after stirring for 5 minutes, a monomer mixture consisting of 1657 g of MMA, 21.6 g of BA, and 1.68 g of ALMA was added all at once, and after the exothermic peak was detected, the mixture was held for another 20 minutes to polymerize the innermost hard layer. Completed.
　次に、ＡＰＳ３．４８ｇを投入し、５分間攪拌後にＢＡ８１０５ｇ、ＰＥＧＤＡ（２００）３１．９ｇ、およびＡＬＭＡ２６４．０ｇからなる単量体混合物を１２０分間かけて連続的に添加し、添加終了後さらに１２０分間保持して、軟質層の重合を完結させた。 Next, 3.48 g of APS was added, and after stirring for 5 minutes, a monomer mixture consisting of BA 8105 g, PEGDA (200) 31.9 g, and ALMA 264.0 g was continuously added over 120 minutes. Hold for a minute to complete the polymerization of the soft layer.
　次に、ＡＰＳ１．３２ｇを投入し、５分間攪拌後にＭＭＡ２１０６ｇ、ＢＡ２０１．６ｇからなる単量体混合物を２０分間かけて連続的に添加し、添加終了後さらに２０分間保持して最外硬質層１の重合を完結した。 Next, 1.32 g of APS was added, and after stirring for 5 minutes, a monomer mixture consisting of 2106 g of MMA and 201.6 g of BA was continuously added over 20 minutes. The polymerization of was completed.
　次いで、ＡＰＳ１．３２ｇを投入し、５分後にＭＭＡ３１４８ｇ、ＢＡ２０１．６ｇ、およびｎ－ＯＭ１０．１ｇからなる単量体混合物を２０分間かけて連続的に添加し、添加終了後にさらに２０分間保持した。ついで９５℃に昇温し６０分間保持して、最外硬質層２の重合を完結させた。 Next, 1.32 g of APS was added, and after 5 minutes, a monomer mixture consisting of 3148 g of MMA, 201.6 g of BA, and 10.1 g of n-OM was continuously added over 20 minutes, and the mixture was further maintained for 20 minutes after the addition was completed. Next, the temperature was raised to 95 ° C. and held for 60 minutes to complete the polymerization of the outermost hard layer 2.
　このようにして得られた重合体ラテックスを少量採取し、吸光度法により平粒子径を求めたところ０．１０μｍであった。残りのラテックスを３質量％硫酸ナトリウム温水溶液中へ投入して、塩析・凝固させ、次いで、脱水・洗浄を繰り返したのち乾燥し、３層構造のアクリル粒子ＡＣ１を得た。 A small amount of the polymer latex thus obtained was collected, and the flat particle size was determined by the absorbance method, which was 0.10 μm. The remaining latex was put into a 3% by mass sodium sulfate warm aqueous solution, salted out and coagulated, then dried and repeatedly dried to obtain acrylic particles AC1 having a three-layer structure.
　上記の略号は各々下記材料である。 The above abbreviations are the following materials.
　ＭＭＡ；メチルメタクリレート
　ＭＡ；メチルアクリレート
　ＢＡ；ｎ－ブチルアクリレート
　ＡＬＭＡ；アリルメタクリレート
　ＰＥＧＤＡ；ポリエチレングリコールジアクリレート（分子量２００）
　ｎ－ＯＭ；ｎ－オクチルメルカプタン
　ＡＰＳ；過硫酸アンモニウム
　＜偏光子保護フィルム試料１０１の作製＞
　（ドープ液１組成）
　ダイヤナールＢＲ８５（三菱レイヨン（株）製）　　　　　６５質量部
　セルロースアセテートプロピオネート（アシル基総置換度２．７５、アセチル基置換度０．２０、プロピオニル基置換度２．５５、Ｍｗ＝２０００００）　　　　　　　　　　　　　　　　　　　　　　　　　　３５質量部
　アクリル粒子（ＡＣ１）　　　　　　　　　　　　　　　１．１質量部
　無機微粒子（アエロジルＲ９７２Ｖ）　　　　　　　　０．２７質量部
　メチレンクロライド　　　　　　　　　　　　　　　　　３００質量部
　エタノール　　　　　　　　　　　　　　　　　　　　　　４０質量部
　上記組成物を、加熱しながら十分に溶解し、ドープ液１を作製した。 MMA; methyl methacrylate MA; methyl acrylate BA; n-butyl acrylate ALMA; allyl methacrylate PEGDA; polyethylene glycol diacrylate (molecular weight 200)
n-OM; n-octyl mercaptan APS; ammonium persulfate <Preparation of polarizer protective film sample 101>
(Dope solution 1 composition)
Dianal BR85 (manufactured by Mitsubishi Rayon Co., Ltd.) 65 parts by mass Cellulose acetate propionate (acyl group total substitution degree 2.75, acetyl group substitution degree 0.20, propionyl group substitution degree 2.55, Mw = 200000) 35 Part by weight Acrylic particles (AC1) 1.1 parts by weight Inorganic fine particles (Aerosil R972V) 0.27 parts by weight Methylene chloride 300 parts by weight Ethanol 40 parts by weight The above composition is sufficiently dissolved while heating to prepare a dope solution 1 did.
　この作製したドープ液を、ベルト流延装置を用い、温度２２℃、２ｍ幅でステンレスバンド支持体に均一に流延した。ステンレスバンド支持体で、残留溶剤量が１００％になるまで溶媒を蒸発させ、剥離張力１６２Ｎ／ｍでステンレスバンド支持体上から剥離した。 The produced dope solution was uniformly cast on a stainless steel band support at a temperature of 22 ° C. and a width of 2 m using a belt casting apparatus. With the stainless steel band support, the solvent was evaporated until the amount of residual solvent reached 100%, and peeling was performed from the stainless steel band support with a peeling tension of 162 N / m.
　剥離した樹脂組成物のウェブを３５℃で溶媒を蒸発させ、１．５ｍ幅にスリットし、その後、テンターで幅方向に１．３０倍（３０％）に延伸しながら、１４０℃の乾燥温度で乾燥させた。このときテンターで延伸を始めたときの残留溶剤量は１０％であった。 The web of the peeled resin composition was evaporated at 35 ° C., slit to 1.5 m width, and then stretched by 1.30 times (30%) in the width direction with a tenter at a drying temperature of 140 ° C. Dried. At this time, the residual solvent amount when starting stretching with a tenter was 10%.
　テンターで延伸後、１３０℃で３０秒間緩和を行った後、１２０℃、１４０℃の乾燥ゾーンを多数のロールで搬送させながら乾燥を終了させ、１．５ｍ幅にスリットし、フィルム両端に幅１０ｍｍ高さ５μｍのナーリング加工を施し、初期張力２２０Ｎ／ｍ、終張力１１０Ｎ／ｍで内径１５．２４ｃｍコアに巻取り、厚さ４０μｍ巻きの長さ５２００ｍの偏光子保護フィルムのロール試料１０１を得た。 After stretching with a tenter, relaxation was performed at 130 ° C. for 30 seconds, and then drying was completed while transporting a drying zone at 120 ° C. and 140 ° C. with a number of rolls, slitting to a width of 1.5 m, and a width of 10 mm at both ends of the film. A knurling process having a height of 5 μm was performed, and the sample was wound around a core having an initial tension of 220 N / m and a final tension of 110 N / m, and an inner diameter of 15.24 cm. .
　以下、表１に記載のように材料及び、条件を変更し試料１０１と同様にして試料１０２～試料１３４を作製した。なお、使用した素材は以下の通りである。 Hereinafter, samples 102 to 134 were prepared in the same manner as the sample 101 with the materials and conditions changed as shown in Table 1. The materials used are as follows.
　＜＜アクリル樹脂＞＞
　Ａ１：モノマー質量比（ＭＭＡ：ＭＡ＝９８：２）、Ｍｗ７５０００
　Ａ２：モノマー質量比（ＭＭＡ：ＭＡ＝９７：３）、Ｍｗ１４００００
　Ａ３：モノマー質量比（ＭＭＡ：ＭＡ＝９７：３）、Ｍｗ５５００００
　Ａ４：モノマー質量比（ＭＭＡ：ＭＡ＝９７：３）、Ｍｗ１１０００００
　　ＭＭＡ：メチルメタクリレート
　　ＭＡ：メチルアクリレート
　ＢＲ８５：ダイヤナールＢＲ８５（三菱レイヨン（株）製）
　　　　　　　　　　　　　　　　　　　　　　　　　Ｍｗ２８００００
　上記市販のアクリル樹脂における分子中のＭＭＡ単位の割合は、９０質量％以上９９質量％以下であった。 << Acrylic resin >>
A1: Monomer mass ratio (MMA: MA = 98: 2), Mw75000
A2: monomer mass ratio (MMA: MA = 97: 3), Mw 140000
A3: monomer mass ratio (MMA: MA = 97: 3), Mw550,000
A4: monomer mass ratio (MMA: MA = 97: 3), Mw 1100000
MMA: Methyl methacrylate MA: Methyl acrylate BR85: Dianal BR85 (manufactured by Mitsubishi Rayon Co., Ltd.)
Mw 280000
The ratio of the MMA unit in the molecule in the commercially available acrylic resin was 90% by mass or more and 99% by mass or less.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　＜アルカリケン化処理＞
　表１記載のロール状試料１０１～試料１３４を各１５００ｍ、下記の二通りのケン化処理（１）、（２）を行い、各々ロール状に同一コアに巻き取った。 <Alkali saponification treatment>
The roll samples 101 to 134 shown in Table 1 were each 1500 m and subjected to the following two saponification treatments (1) and (2), and each roll was wound around the same core.
　（アルカリケン化処理（１）・・・基準ケン化条件）
　　ケン化工程　　２．０Ｍ－ＮａＯＨ　４５℃　　９０秒
　　水洗工程　　　水　　　　　　　　　３０℃　　４５秒
　　中和工程　　　１０質量部ＨＣｌ　　３０℃　　４５秒
　　水洗工程　　　水　　　　　　　　　３０℃　　４５秒
　　乾燥　　　　　　　　　　　　　　　８０℃　３６０秒
　（アルカリケン化処理（２）・・・迅速ケン化条件）
　　ケン化工程　　１．５Ｍ－ＮａＯＨ　５５℃　　４０秒
　　水洗工程　　　水　　　　　　　　　４０℃　　２０秒
　　中和工程　　　１０質量部ＨＣｌ　　４０℃　　２０秒
　　水洗工程　　　水　　　　　　　　　４０℃　　２０秒
　　乾燥　　　　　　　　　　　　　　　９５℃　１８０秒
　＜すべり性評価・摩擦係数の測定＞
　温度２３℃、湿度５５％ＲＨの環境でフィルムを５時間調湿した後、フィルム同士での摩擦係数を、ＪＩＳ－Ｋ－７１２５（１９８７）に規定する方法で測定した。 (Alkali saponification treatment (1) ... standard saponification conditions)
Saponification process 2.0M-NaOH 45 ° C. 90 seconds Water washing process Water 30 ° C. 45 seconds Neutralization process 10 parts HCl 30 ° C. 45 seconds Water washing process Water 30 ° C. 45 seconds Drying 80 ° C. 360 seconds (alkali saponification treatment (2) ... Quick saponification conditions)
Saponification process 1.5M-NaOH 55 ° C. 40 seconds Water washing process Water 40 ° C. 20 seconds Neutralization process 10 parts by weight HCl 40 ° C. 20 seconds Water washing process Water 40 ° C. 20 seconds Drying 95 ° C. 180 seconds Measurement>
After the film was conditioned for 5 hours in an environment of a temperature of 23 ° C. and a humidity of 55% RH, the coefficient of friction between the films was measured by the method specified in JIS-K-7125 (1987).
　ケン化後の摩擦係数は、ケン化処理（１）、ケン化処理（２）の平均値で表した。 The friction coefficient after saponification was expressed as an average value of saponification treatment (1) and saponification treatment (2).
　＜巻き形状・凹凸率＞
　ケン化処理を行った後のロール状のフィルムに対し、ロール幅手の中央について表面の凹凸を測定した。即ちロールの外周１回転分の測定から凹凸の差が最大となる値Ｘｍを求めた。さらに同一箇所でのロール最表面からロールのコアまでの厚みＲｍを１回転した平均値から算出し、Ｘｍ／Ｒｍ×１００（％）を凹凸率として求めた。表１には、ケン化条件（１）、ケン化条件（２）の平均値で表した。 <Roll shape / Roughness ratio>
With respect to the roll-shaped film after the saponification treatment, surface irregularities were measured at the center of the roll width. That is, the value Xm that maximizes the difference in unevenness was obtained from the measurement for one rotation of the outer periphery of the roll. Furthermore, the thickness Rm from the roll outermost surface to the core of the roll at the same location was calculated from an average value obtained by one rotation, and Xm / Rm × 100 (%) was obtained as the unevenness ratio. In Table 1, it represented with the average value of saponification conditions (1) and saponification conditions (2).
　＜偏光板の作製＞
　厚さ１２０μｍの長尺ロールポリビニルアルコールフィルムを沃素１質量部、ホウ酸４質量部を含む水溶液１００質量部に浸漬し、５０℃で６倍に製膜方向に延伸して偏光子を作製した。 <Preparation of polarizing plate>
A 120 μm-thick long roll polyvinyl alcohol film was immersed in 100 parts by mass of an aqueous solution containing 1 part by mass of iodine and 4 parts by mass of boric acid, and stretched 6 times at 50 ° C. in the film forming direction to produce a polarizer.
　次に、ポリビニルアルコール系の水性接着剤（２．５質量％溶液）を用いて、偏光子の透過軸と先にケン化処理を行った試料の面内遅相軸が平行になるように偏光子の両面にケン化後の試料１０１～試料１３４を貼り合わせ偏光板１０１～１３４を作製した。この様にして、各フィルムに対しケン化条件の異なる２種類の偏光板を作製した。 Next, using a polyvinyl alcohol-based aqueous adhesive (2.5% by mass solution), polarization is performed so that the transmission axis of the polarizer is parallel to the in-plane slow axis of the saponified sample. The saponified samples 101 to 134 were bonded to both sides of the child to produce polarizing plates 101 to 134. In this way, two types of polarizing plates having different saponification conditions were produced for each film.
　＜偏光子密着性＞
　作製した偏光板の密着性を以下の基準にて評価した。 <Polarizer adhesion>
The adhesion of the produced polarizing plate was evaluated according to the following criteria.
　各偏光板を各々５ｃｍ×７ｃｍのサイズに切断した。得られた切断片を各々６ｃｍ×８ｃｍのガラス板の中央部にアクリル系粘着剤で仮粘着し、次いでこれらを押圧して各片とガラス板の間の気泡を完全に除去するようにして各切断をガラス板に粘着した。 Each polarizing plate was cut into a size of 5 cm × 7 cm. The obtained cut pieces are each temporarily attached to the center of a 6 cm × 8 cm glass plate with an acrylic adhesive, and then pressed to completely remove bubbles between the pieces and the glass plate. Sticked to a glass plate.
　こうして作製した試験片を８０℃、９０％ＲＨにセットした恒温恒湿オーブン内に互いに重ならないように垂直に配して支持枠に５００時間固定した後、各片について偏光子と試料１０１～試料１３４のフィルムの密着性の測定を行った。 The test pieces thus prepared were placed vertically in a constant temperature and humidity oven set at 80 ° C. and 90% RH so as not to overlap each other and fixed to the support frame for 500 hours. The adhesion of 134 films was measured.
　偏光子とアクリルフィルムのみ密着性の評価：高温高湿処理後目視により観察を行い偏光子と保護フィルムの間の剥離状態を評価し以下の基準で表した。
○：膜の浮き上がりの部分がまったく見当たらない
△：膜の浮き上がりの部分が周辺１～５ｍｍの範囲
×：膜の浮き上がりの部分が周辺５ｍｍ以上
　＜偏光子透過率＞
　偏光子密着性と同様にして、８０℃、９０％ＲＨ、５００時間の偏光板の劣化試験を行い、劣化試験前後での偏光子の透過率の差を求め以下の評価基準で表した。
○：劣化試験での透過率差が０．５％未満
△：劣化試験での透過率差が５％未満
×：劣化試験での透過率差が５％以下
　＜液晶表示装置の作製＞
　上記作製したケン化条件（２）から成る偏光板を使用して、本発明のフィルムの表示特性評価を行った。横電解モード型液晶表示装置である日立製液晶テレビＷｏｏｏ　Ｗ３２－Ｌ７０００を用いて、予め貼合されていた両面の偏光板を剥がして、上記作製した偏光板をそれぞれ液晶セルのガラス面に貼合した。 Evaluation of adhesion between the polarizer and the acrylic film only: The peeled state between the polarizer and the protective film was evaluated by visual observation after the high-temperature and high-humidity treatment, and represented by the following criteria.
○: No film lifted part is found Δ: Film lifted part is in the range of 1 to 5 mm in the periphery ×: Film lifted part is in the periphery 5 mm or more <Polarizer transmittance>
In the same manner as the polarizer adhesion, a deterioration test of the polarizing plate at 80 ° C., 90% RH, and 500 hours was performed, and the difference in the transmittance of the polarizer before and after the deterioration test was obtained and expressed by the following evaluation criteria.
○: Transmittance difference in degradation test is less than 0.5% Δ: Transmittance difference in degradation test is less than 5% ×: Transmittance difference in degradation test is 5% or less <Production of liquid crystal display device>
Using the produced polarizing plate having the saponification condition (2), the display characteristics of the film of the present invention were evaluated. Using a Hitachi LCD TV Woo W32-L7000, which is a horizontal electrolysis mode type liquid crystal display device, the polarizing plates on both sides previously bonded are peeled off, and the prepared polarizing plates are bonded to the glass surfaces of the liquid crystal cells, respectively. did.
　上記作製した偏光板を予め貼合されていた偏光板と同一の方向に吸収軸が向くように貼合し、液晶表示装置を各々作製した。 The above-prepared polarizing plate was bonded so that the absorption axis was in the same direction as the polarizing plate that had been bonded in advance, and each liquid crystal display device was manufactured.
　（画像ムラ）
　以上のようにして作製した液晶表示装置を用いてグレーの均一画像を目視評価し以下の基準で表した。
○：画像ムラが全くない
△：非常に細かく注意すると僅かに画像のムラが認められる
×：三角形、楕円形の画像ムラが見える (Image unevenness)
Using the liquid crystal display device produced as described above, a gray uniform image was visually evaluated and represented by the following criteria.
○: No image irregularity △: Slight image unevenness is observed with very careful attention ×: Triangular and elliptical image irregularities are visible
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表２から明らかなように本発明の試料は、迅速のケン化処理を行っても十分な密着性と画像安定性が確保されていることが判る。 As is apparent from Table 2, it can be seen that the sample of the present invention has sufficient adhesion and image stability even after rapid saponification treatment.

Claims (7)

  1. 　アクリル樹脂（Ａ）とセルロースエステル樹脂（Ｂ）を８５：１５～３０：７０の質量比で含有する偏光子保護フィルムであって、ケン化処理が施されたときに、当該ケン化処理後の摩擦係数が当該ケン化処理前の摩擦係数に対し小さいことを特徴とする偏光子保護フィルム。 A polarizer protective film containing an acrylic resin (A) and a cellulose ester resin (B) in a mass ratio of 85:15 to 30:70, and when subjected to saponification treatment, A polarizer protective film having a friction coefficient smaller than that before the saponification treatment.
  2. 　微粒子を含有することを特徴とする請求項１に記載の偏光子保護フィルム。 The polarizer protective film according to claim 1, further comprising fine particles.
  3. 　前記微粒子として、無機微粒子を含有することを特徴とする請求項２に記載の偏光子保護フィルム。 The polarizer protective film according to claim 2, wherein the fine particles contain inorganic fine particles.
  4. 　前記微粒子として、無機微粒子とアクリル粒子を含有することを特徴とする請求項２又は請求項３に記載の偏光子保護フィルム。 The polarizer protective film according to claim 2 or 3, wherein the fine particles contain inorganic fine particles and acrylic particles.
  5. 　偏光子及び当該偏光子を挟む２枚の偏光子保護フィルムを具備した偏光板であって、当該偏光子保護フィルムのうち少なくとも１枚が請求項１から請求項４までのいずれか一項に記載の偏光子保護フィルムであることを特徴とする偏光板。 A polarizing plate comprising a polarizer and two polarizer protective films sandwiching the polarizer, wherein at least one of the polarizer protective films is according to any one of claims 1 to 4. A polarizing plate characterized by being a polarizer protective film.
  6. 　請求項５に記載の偏光板を製造する偏光板の製造方法であって、請求項１から請求項４までのいずれか一項に記載の偏光子保護フィルムをケン化処理する工程を有することを特徴とする偏光板の製造方法。 It is a manufacturing method of the polarizing plate which manufactures the polarizing plate of Claim 5, Comprising: It has the process of saponifying the polarizer protective film as described in any one of Claim 1- Claim 4. A method for producing a polarizing plate.
  7. 　前記ケン化処理する工程において、ケン化から乾燥直前の水洗までを１８０秒以内で処理することを特徴とする請求項６に記載の偏光板の製造方法。 The method for producing a polarizing plate according to claim 6, wherein in the saponification treatment, the treatment from saponification to washing immediately before drying is performed within 180 seconds.
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US20220379539A1 (en) * 2016-09-29 2022-12-01 Kuraray Co., Ltd. Acrylic resin film and production method therefor

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