WO2016203947A1 - Production method for polarizing plate with protective film - Google Patents
Production method for polarizing plate with protective film Download PDFInfo
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- WO2016203947A1 WO2016203947A1 PCT/JP2016/066166 JP2016066166W WO2016203947A1 WO 2016203947 A1 WO2016203947 A1 WO 2016203947A1 JP 2016066166 W JP2016066166 W JP 2016066166W WO 2016203947 A1 WO2016203947 A1 WO 2016203947A1
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- WIPO (PCT)
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- film
- polarizing plate
- thermoplastic resin
- protective film
- curl
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
Definitions
- the present invention relates to a method for producing a polarizing plate with a protective film obtained by laminating a protective film on the surface of the polarizing plate.
- the polarizing plate used is also required to have high brightness and thin and light weight.
- a polarizing plate made of a polyvinyl alcohol resin and a protective film made of triacetyl cellulose (TAC) bonded with an adhesive is generally used as the polarizing plate.
- TAC triacetyl cellulose
- a protective film made of a resin other than TAC has been used from the viewpoints of thinning, durability, cost, productivity, and the like [for example, Japanese Patent Application Laid-Open No. 2004-245925 (Patent Document 1). ]].
- the polarizing plate is sensitive to the environment in which it is placed, and depending on the environmental conditions, it tends to bend like a bow. In this specification, this deformation is also referred to as “curl”. There are two types of curls: “normal curls” and “reverse curls”.
- the polarizing plate has a first main surface on the side to be bonded to an image display element such as a liquid crystal cell and a second main surface opposite to the first main surface.
- the curl is convex on the surface side, and the “reverse curl” is the curl convex on the second main surface side.
- an object of the present invention is to provide a method capable of manufacturing an optical member including a polarizing plate structure, in which reverse curl is sufficiently suppressed.
- the present inventor 1 The polarizing plate is usually marketed as a polarizing plate with a protective film to which a peelable protective film (also referred to as a surface protective film) for protecting the surface of the polarizing plate is attached.
- a peelable protective film also referred to as a surface protective film
- bonding is performed in the form of a polarizing plate with a protective film
- this invention provides the manufacturing method of the polarizing plate with a protective film shown below.
- a method for producing a polarizing plate with a protective film including a step of pressing a protective film on one side of the polarizing plate and pressing it between a pair of bonding rolls, In the pair of bonding rolls, the surface hardness H 1 of the bonding roll contacting the protect film, measured by a type A durometer hardness tester defined in JIS K 6253, and contacting the polarizing plate. and the surface hardness of H 2 lamination rolls, the following formula (I): H 1 > H 2 (I) A manufacturing method that satisfies the above relationship.
- the polarizing plate includes a polarizing film, a first thermoplastic resin film laminated on one surface thereof, and a second thermoplastic resin film laminated on the other surface, [1] or [ 2].
- thermoplastic resin film has a higher equilibrium moisture content at a temperature of 23 ° C. and a relative humidity of 55% than the second thermoplastic resin film.
- a polarizing plate with a protective film in which reverse curling is sufficiently suppressed can be manufactured. According to this polarizing plate with a protective film, it is possible to carry out the bonding to the image display element with high productivity while suppressing the above problems.
- the manufacturing method of a polarizing plate with a protective film according to the present invention is such that the protective film 1 is stacked on one side of the polarizing plate 2 and a pair of bonding rolls 5, 5 ′.
- the polarizing plate 3 with a protective film is manufactured by the said process including the process of pressing the laminated body of the protective film 1 and the polarizing plate 2 from the upper and lower sides.
- each of the protective film 1 and the polarizing plate 2 subjected to the pressing step is continuously fed from a feeding roll (not shown) and continuously conveyed, and between a pair of bonding rolls 5 and 5 ′. be introduced.
- the transport direction of the protective film 1 and the polarizing plate 2 is the film longitudinal direction, and the transport directions of both are usually parallel.
- MD means the machine flow direction of the film, that is, the longitudinal direction of the film.
- the direction orthogonal to MD, that is, the film width direction is also referred to as TD in this specification.
- the bonding roll 5 having a large surface hardness is protected in the state where the surface hardness of the bonding roll 5 ′ having a low hardness has bite into the nip portion.
- the protective film 1 and the polarizing plate 2 are bonded in a shape in which the main surface on which the protective film 1 is stacked is concave.
- the shape of the polarizing plate 2 is corrected (curl correction) in a direction in which the main surface on which the protective film 1 is superimposed is concave (that is, the positive curl direction). be able to. Therefore, for example, when the polarizing plate 2 that is subjected to the pressing step is a sheet, if it causes reverse curl (curl having a convex main surface on which the protective film 1 is superimposed), the present invention. Therefore, the reverse curl can be corrected in the normal curl direction. As a result, the reverse curl is sufficiently suppressed when the sheet body is formed, is flat with no curl, or is normal.
- a polarizing plate 3 with a protective film having curl can be obtained. When the obtained polarizing plate 3 with a protective film is a sheet, it preferably has no curl and is flat or has a positive curl.
- the surface hardness H 1 of the bonding roll 5 is, for example, 90 ° to 100 °, and may be 95 ° to 100 °.
- the surface hardness of H 2 lamination rolls 5 ' is, for example, a 60 ° ⁇ 90 °, may be 70 ° ⁇ 80 °.
- the hardness of the bonding rolls 5 and 5 ′ can be measured with a type A durometer hardness tester defined in JIS K 6253. As a commercially available hardness meter, for example, a rubber hardness meter “Type-A” manufactured by Asuka Corporation is used. Specifically, the resistance of the surface of the bonding roll when the surface is pressed with a stick or the like is measured with a hardness meter.
- the relationship of the above formula (I) can be realized by appropriately selecting the material of the surface of each of the bonding roll 5 and the bonding roll 5 '.
- the surface of the bonding roll means from the surface in contact with the protective film or polarizing plate of the bonding roll to a depth of at least 5 mm toward the rotation center axis of the bonding roll.
- Each of the bonding rolls 5 and 5 ′ may be formed of the same material, or the surface material of the bonding roll is different from the material inside the bonding roll covered with the surface material. It may be.
- a / B indicates the surface material of the bonding roll 5 / the surface material of the bonding roll 5 ′
- metal / Rubber for example, metal / Rubber, alloy / rubber, elastic metal / rubber, rubber / rubber and the like.
- the metal iron, aluminum or the like can be used.
- the alloy stainless steel can be used, and preferably SUS304 (stainless steel containing 18% Cr and 8% Ni) can be used.
- SUS304 stainless steel containing 18% Cr and 8% Ni
- the material of the bonding roll is a metal and / or alloy, it is preferable to perform surface treatment such as chromium plating, nickel plating, DLC (diamond-like carbon) for the purpose of improving corrosion resistance and scratch resistance. Further, the surface treatment may be a single layer or a plurality of layers.
- the elastic metal means a structure in which the surface of an elastic body such as rubber or oil is covered with a metal layer having a thickness of 0.2 to 2 mm.
- a metal layer on the outermost surface of the elastic metal nickel, stainless steel or the like can be used.
- the metal layer on the outermost surface of the elastic metal is preferably subjected to a surface treatment such as chromium plating, nickel plating, or DLC (diamond-like carbon) for the purpose of improving corrosion resistance and scratch resistance.
- NBR nitrile rubber
- Titan urethane
- silicon silicon
- EPDM ethylene-propylene-diene rubber
- the lamination rolls 5' surface hardness H of the 2 is preferably 60 ° to 90 °.
- the diameter of the bonding roll 5 and the bonding roll 5 ' is preferably 50 mm to 300 mm, and more preferably 100 mm to 200 mm.
- the diameter is less than 50 mm, the reverse curl correction effect becomes strong, and the normal curl may become larger than necessary.
- the diameter exceeds 300 mm the curvature of the nip portion becomes small, and there is a possibility that a sufficient reverse curl correction effect cannot be obtained.
- Curling refers to a deformation in which an optical member (optical film) such as the polarizing plate 2 or the polarizing plate 3 with a protective film warps in a bow shape, and this deformation usually occurs in a sheet of the optical member. Curling tends to occur more easily as the optical member becomes thinner.
- optical member optical film
- the curl can be classified into two types, “normal curl” and “reverse curl”, depending on which one of the two opposing main surfaces of the optical member is convex and curled.
- the main surface on the side to be bonded to the image display element such as a liquid crystal cell is the first main surface and the main surface on the opposite side is the second main surface
- the “normal curl” is the first main surface.
- the curl is convex on the side
- “reverse curl” is the curl convex on the second main surface side.
- the polarizing plate 2 provided for the production method according to the present invention is made into a sheet, it typically produces reverse curl (curl having a convex main surface on which the protective film 1 is superimposed). is there.
- the curl can be classified into two types, “MD curl” and “TD curl”, depending on which end (side) of the optical member which is a sheet.
- MD curl is the end of MD (typically both ends).
- TD curl is a curl in which ends (typically both ends) in TD are lifted. According to the manufacturing method of the present invention, both MD curl and TD curl can be effectively corrected.
- the polarizing plate 3 with a protective film which is sufficiently curled when it is made into a sheet, preferably flat without curling, or having normal curling. it can.
- this polarizing plate 3 with a protective film when bonding to an image display element via an adhesive layer, a bonding error occurs or bubbles are mixed into the interface between the adhesive layer and the image display element. A malfunction can be suppressed effectively and pasting with polarizing plate 3 with a protective film and an image display element can be carried out with sufficient productivity.
- the curl generated in the polarizing plate 3 with the protective film is a positive curl, and even if the curl amount is relatively large, there is no particular problem in terms of the above problems and productivity.
- the polarizing plate 3 with a protective film obtained by the present invention may have a reverse curl to the extent that the above problems can be suppressed (preferably not causing the above problems).
- the correction amount in the positive curl direction depends on the difference between the left side and the right side of the formula (I), and the correction amount tends to increase as the difference increases.
- the pressing step is represented by the following formula (II): H 1 -H 2 ⁇ 10 (II) It is preferable to carry out under conditions that satisfy the above conditions.
- the above formula (II) May have to be greater than 20 (for example, 30 or more or 35 or more).
- the left side of the formula (II) may be 40 or less, for example.
- the adhesive layer of the protective film 1 is in contact with the one side of the polarizing plate 2.
- plasma treatment, corona treatment, ultraviolet irradiation treatment, frame (flame) treatment is applied to at least one of the adhesive layer of the protective film 1 and the polarizing plate 2.
- a surface activation treatment such as a saponification treatment may be performed.
- the pressure (nip pressure) applied to the laminate of the protective film 1 and the polarizing plate 2 is, for example, 0.01 to 1 MPa, and 0.05 to 0. It may be 5 MPa.
- the width (nip width) between the bonding roll 5 and the bonding roll 5 ′ is, for example, 1 to 20 mm, and 5 to 15 mm. Also good. When the nip pressure and the nip width are below the exemplified ranges, the curl correction effect may be weakened.
- the protect film 1 is usually composed of a base film and an adhesive layer laminated thereon.
- the protective film 1 is a film for protecting the surface of the polarizing plate 2, and usually, for example, after the polarizing plate 3 with a protective film is bonded to an image display element or the like, the entire adhesive layer that it has is peeled and removed.
- the base film is a thermoplastic resin, for example, a polyolefin resin such as a polyethylene resin, a polypropylene resin, or a cyclic polyolefin resin; a polyester resin such as polyethylene terephthalate or polyethylene naphthalate; a polycarbonate resin; a (meth) acrylic resin It can be made of resin or the like.
- the pressure-sensitive adhesive layer can be composed of a (meth) acrylic pressure-sensitive adhesive, an epoxy-based pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, and the like. Moreover, it can also be comprised with the resin layer which has self-adhesiveness, such as a polypropylene-type resin and a polyethylene-type resin.
- (meth) acrylic resin represents at least one selected from the group consisting of acrylic resins and methacrylic resins. The same applies to other terms with “(meta)”.
- the thickness T 1 of the protect film 1 can be, for example, 5 to 200 ⁇ m, preferably 10 to 150 ⁇ m, more preferably 20 to 120 ⁇ m, and further preferably 25 to 100 ⁇ m (for example, 90 ⁇ m or less).
- the thickness T 1 is less than 5 ⁇ m, the protection of the polarizing plate 2 may be insufficient, and it is disadvantageous in terms of handleability. Furthermore, the strength is insufficient, and the curl correction effect may be reduced.
- the thickness T 1 exceeding 200 ⁇ m is disadvantageous in terms of cost and reworkability of the protective film 1.
- the thickness of the polarizing film and the protective film constituting the polarizing plate can be adjusted for the purpose of curl correction.
- the polarizing plate 2 is a polarizing element including at least a polarizing film, and further includes a thermoplastic resin film such as a protective film which is usually laminated on at least one surface of the polarizing film.
- a protective film is an optical film which bears protection of a polarizing film.
- the polarizing plate 2 can include a layer or film other than the polarizing film and the protective film, for example, an optical layer or an optical film having an optical function other than the polarizing film.
- the optical layer or optical film having other optical functions include a retardation film (or retardation layer), a brightness enhancement film, and the like.
- Various optical films including a protective film can be laminated and bonded onto a polarizing film via an adhesive layer or a pressure-sensitive adhesive layer.
- the polarizing plate 2 may have a surface treatment layer (coating layer) such as a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, and an antifouling layer.
- the thickness T 2 of the polarizing plate 2 is usually 200 ⁇ m or less, and is preferably 125 ⁇ m or less, more preferably 100 ⁇ m or less, and even more preferably 75 ⁇ m or less from the viewpoint of thinning.
- the polarizing plate 2 is thin and the polarizing plate 2 is a sheet, Even if the curl is generated, the reverse curl can be effectively corrected in the normal curl direction.
- the polarizing plate 2a shown in FIG. 3 includes a polarizing film 10; a first thermoplastic resin film 20 bonded to one surface of the polarizing film 10, and a second thermoplastic material bonded to the other surface of the polarizing film 10.
- the separate film 50 is a peelable film for protecting the surface (outer surface) of the pressure-sensitive adhesive layer 40.
- the first and second thermoplastic resin films 20 and 30 are, for example, protective films.
- one of the first and second thermoplastic resin films 20 and 30 may be omitted.
- the second thermoplastic resin film 30 is omitted, and the pressure-sensitive adhesive layer 40 is directly formed on the outer surface of the polarizing film 10 (the surface opposite to the surface on which the first thermoplastic resin film 20 is laminated). Is pasted.
- Such a polarizing plate having a thermoplastic resin film only on one surface of the polarizing film 10 is advantageous for thinning the polarizing plate.
- the thermoplastic resin film is laminated only on one surface of the polarizing film 10
- the polarizing plate 2 is likely to curl in the sheet, but according to the present invention, only one surface of the polarizing film 10 is present. Even if the thermoplastic resin film is laminated and bonded, the reverse curl can be effectively corrected in the normal curl direction even when the polarizing plate 2 forms a sheet. .
- the adhesive layer 40 and the separate film 50 may be omitted as in the polarizing plate 2c shown in FIG.
- the polarizing plate 2 may have a protective film different from the protective film 1 used for the pressing step on one side in advance.
- the obtained polarizing plate 3 with a protective film is a polarizing plate having protective films on both sides.
- the polarizing film 10 and the first and second thermoplastic resin films 20 and 30 can be preferably bonded using an adhesive.
- the polarizing film 10 can be obtained by adsorbing and orienting a dichroic dye on a uniaxially stretched polyvinyl alcohol resin film.
- a saponified polyvinyl acetate resin can be used as the polyvinyl alcohol resin constituting the polyvinyl alcohol resin film.
- the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith.
- Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth) acrylamides having an ammonium group.
- the degree of saponification of the polyvinyl alcohol-based resin can be in the range of 80.0 to 100.0 mol%, preferably in the range of 90.0 to 100.0 mol%, more preferably 94.0. It is in the range of ⁇ 100.0 mol%.
- the saponification degree is less than 80.0 mol%, the water resistance and heat-and-moisture resistance of the obtained polarizing plate 2 may be lowered.
- the degree of saponification is the unit ratio (mol%) of the ratio of acetate groups (acetoxy groups: —OCOCH 3 ) contained in polyvinyl acetate resin, which is a raw material for polyvinyl alcohol resins, to hydroxyl groups by the saponification process.
- the following formula: Degree of saponification (mol%) 100 ⁇ (number of hydroxyl groups) / (number of hydroxyl groups + number of acetate groups) Defined by The saponification degree can be determined according to JIS K 6726 (1994). The higher the degree of saponification, the higher the proportion of hydroxyl groups, and thus the lower the proportion of acetate groups that inhibit crystallization.
- the average degree of polymerization of the polyvinyl alcohol-based resin is preferably 100 to 10,000, more preferably 1500 to 8000, and further preferably 2000 to 5000.
- the average degree of polymerization of the polyvinyl alcohol resin can also be determined according to JIS K 6726 (1994). If the average degree of polymerization is less than 100, it is difficult to obtain a preferable polarizing performance, and if it exceeds 10,000, the solubility in a solvent is deteriorated, and it may be difficult to form a polyvinyl alcohol-based resin film.
- the dichroic dye contained (adsorption orientation) in the polarizing film 10 can be iodine or a dichroic organic dye.
- the dichroic organic dye include: Red BR, Red LR, Red R, Pink LB, Rubin BL, Bordeaux GS, Sky Blue LG, Lemon Yellow, Blue BR, Blue 2R, Navy RY, Green LG, Violet LB, Violet B, Black H, Black B, Black GSP, Yellow 3G, Yellow R, Orange LR, Orange 3R, Scarlet GL, Scarlet KGL, Congo Red, Brilliant Violet BK, Spura Blue G, Spura Blue GL, Spura Orange GL, Direct Includes Sky Blue, Direct First Orange S and First Black.
- a dichroic dye may be used individually by 1 type, and may use 2 or more types together.
- the dichroic dye is preferably iodine.
- the polarizing film 10 is a step of uniaxially stretching a polyvinyl alcohol-based resin film; a step of adsorbing a dichroic dye by dyeing the polyvinyl alcohol-based resin film with a dichroic dye; a polyvinyl on which the dichroic dye is adsorbed It can be manufactured through a step of crosslinking the alcohol-based resin film; and a step of washing with water after the crosslinking treatment.
- the polyvinyl alcohol resin film is a film obtained by forming the polyvinyl alcohol resin described above.
- the film forming method is not particularly limited, and a known method such as a melt extrusion method or a solvent casting method can be employed.
- the thickness of the polyvinyl alcohol-based resin film is, for example, about 10 to 150 ⁇ m, preferably 50 ⁇ m or less, more preferably 35 ⁇ m or less.
- the uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before, simultaneously with, or after the dyeing of the dichroic dye.
- this uniaxial stretching may be performed before or during the crosslinking treatment. Moreover, you may uniaxially stretch in these several steps.
- rolls having different peripheral speeds may be uniaxially stretched or may be stretched uniaxially using a hot roll.
- the uniaxial stretching may be dry stretching in which stretching is performed in the air, or may be wet stretching in which a polyvinyl alcohol-based resin film is stretched in a solution.
- the draw ratio is usually about 3 to 8 times.
- a method of dyeing a polyvinyl alcohol resin film with a dichroic dye for example, a method of immersing the polyvinyl alcohol resin film in an aqueous solution (dye solution) containing the dichroic dye is employed.
- the polyvinyl alcohol-based resin film is preferably subjected to an immersion treatment (swelling treatment) in water before the dyeing treatment.
- iodine When iodine is used as the dichroic dye, a method of dyeing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide is usually employed.
- the iodine content in this dyeing aqueous solution is usually 0.01 to 1 part by weight per 100 parts by weight of water.
- the content of potassium iodide is usually 0.5 to 20 parts by weight per 100 parts by weight of water.
- the temperature of the dyeing aqueous solution is usually about 20 to 40 ° C.
- a method of dyeing a polyvinyl alcohol resin film by immersing it in a dyeing aqueous solution containing a water-soluble dichroic organic dye is usually employed.
- the content of the dichroic organic dye in the aqueous dyeing solution is usually 1 ⁇ 10 ⁇ 4 to 10 parts by weight, preferably 1 ⁇ 10 ⁇ 3 to 1 part by weight per 100 parts by weight of water.
- This dyeing aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing aid.
- the temperature of the dyeing aqueous solution is usually about 20 to 80 ° C.
- the crosslinking treatment after dyeing with the dichroic dye can be performed by immersing the dyed polyvinyl alcohol resin film in an aqueous solution containing a crosslinking agent.
- a crosslinking agent is boric acid, but other cross-linking agents such as boron compounds such as borax, glyoxal, and glutaraldehyde can also be used. Only 1 type may be used for a crosslinking agent and it may use 2 or more types together.
- the amount of the crosslinking agent in the aqueous solution containing the crosslinking agent is usually 2 to 15 parts by weight, preferably 5 to 12 parts by weight per 100 parts by weight of water.
- the aqueous solution containing a crosslinking agent preferably contains potassium iodide.
- the amount of potassium iodide in the crosslinking agent-containing aqueous solution is usually 0.1 to 15 parts by weight, preferably 5 to 12 parts by weight per 100 parts by weight of water.
- the temperature of the aqueous solution containing a crosslinking agent is usually 50 ° C. or higher, preferably 50 to 85 ° C.
- the polyvinyl alcohol resin film after the crosslinking treatment is usually washed with water.
- the water washing treatment can be performed, for example, by immersing the crosslinked polyvinyl alcohol resin film in water.
- the temperature of water in the water washing treatment is usually about 1 to 40 ° C.
- the polarizing film 10 is obtained by performing a drying process after washing with water.
- the drying treatment can be drying with a hot air dryer, drying by contacting with a hot roll, drying with a far infrared heater, and the like.
- the temperature for the drying treatment is usually about 30 to 100 ° C., preferably 50 to 90 ° C.
- the thickness of the polarizing film 10 is usually about 2 to 40 ⁇ m. From the viewpoint of thinning the polarizing plate 2, the thickness of the polarizing film 10 is preferably 20 ⁇ m or less, more preferably 15 ⁇ m or less, and even more preferably 10 ⁇ m or less. As the thickness of the polarizing film 10 is smaller, the polarizing plate 2 is more likely to curl in the sheet. However, according to the present invention, when the polarizing film 10 is small and the polarizing plate 2 is a sheet, Even if the curl is generated, the reverse curl can be effectively corrected in the normal curl direction.
- the first and second thermoplastic resin films 20 and 30 are each independently a light-transmitting thermoplastic resin, preferably optically transparent heat. It is a film composed of a plastic resin.
- the thermoplastic resin constituting the first and second thermoplastic resin films 20 and 30 is, for example, a polyolefin resin such as a chain polyolefin resin (polypropylene resin or the like) or a cyclic polyolefin resin (norbornene resin or the like).
- a cellulose resin such as triacetyl cellulose and diacetyl cellulose; a polyester resin such as polyethylene terephthalate and polybutylene terephthalate; a polycarbonate resin; a (meth) acrylic resin such as a methyl methacrylate resin; a polystyrene resin; Polyvinyl chloride resin; Acrylonitrile butadiene styrene resin; Acrylonitrile styrene resin; Polyvinyl acetate resin; Polyvinylidene chloride resin; Polyamide resin; Polyacetal resin; Modified polyphenylene Ether-based resins; polysulfone resins; poly (ether sulfone) resins; polyarylate resin; polyamideimide resin; may be a polyimide resin or the like.
- chain polyolefin resin examples include a homopolymer of a chain olefin such as a polyethylene resin and a polypropylene resin, and a copolymer composed of two or more chain olefins. More specific examples include polypropylene resins (polypropylene resins that are homopolymers of propylene and copolymers mainly composed of propylene), polyethylene resins (polyethylene resins that are homopolymers of ethylene and ethylene mainly) A copolymer).
- Cyclic polyolefin-based resin is a general term for resins that are polymerized using cyclic olefins as polymerization units.
- Specific examples of cyclic polyolefin resins include ring-opening (co) polymers of cyclic olefins, addition polymers of cyclic olefins, copolymers of cyclic olefins and chain olefins such as ethylene and propylene (typically Are random copolymers), graft polymers obtained by modifying them with unsaturated carboxylic acids or derivatives thereof, and hydrides thereof.
- norbornene resins using norbornene monomers such as norbornene and polycyclic norbornene monomers as cyclic olefins are preferably used.
- Cellulosic resins are those in which some or all of the hydrogen atoms in the hydroxyl groups of cellulose obtained from raw material cellulose such as cotton linter and wood pulp (hardwood pulp, conifer pulp) are substituted with acetyl groups, propionyl groups and / or butyryl groups. Further, it refers to a cellulose organic acid ester or a cellulose mixed organic acid ester. For example, cellulose acetate, propionate, butyrate, and mixed esters thereof can be used. Among these, triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, and cellulose acetate butyrate are preferable.
- the polyester-based resin is a resin other than the above cellulose-based resin having an ester bond, and is generally made of a polycondensate of a polyvalent carboxylic acid or a derivative thereof and a polyhydric alcohol.
- a polyvalent carboxylic acid or a derivative thereof a divalent dicarboxylic acid or a derivative thereof can be used, and examples thereof include terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl naphthalenedicarboxylate.
- a divalent diol can be used, and examples thereof include ethylene glycol, propanediol, butanediol, neopentyl glycol, and cyclohexanedimethanol.
- suitable polyester-based resins include polyethylene terephthalate.
- Polycarbonate resin is an engineering plastic made of a polymer in which monomer units are bonded via a carbonate group, and is a resin having high impact resistance, heat resistance, flame retardancy, and transparency.
- the polycarbonate-based resin may be a resin called a modified polycarbonate in which the polymer skeleton is modified in order to lower the photoelastic coefficient, a copolymerized polycarbonate with improved wavelength dependency, or the like.
- (Meth) acrylic resin is a polymer containing structural units derived from (meth) acrylic monomers.
- the polymer is typically a polymer containing a methacrylic acid ester.
- it is a polymer in which the proportion of structural units derived from methacrylic acid esters is 50% by weight or more based on the total structural units.
- the (meth) acrylic resin may be a methacrylic acid ester homopolymer or a copolymer containing structural units derived from other polymerizable monomers.
- the proportion of structural units derived from other polymerizable monomers is preferably 50% by weight or less based on the total structural units.
- a methacrylic acid alkyl ester As the methacrylic acid ester that can constitute the (meth) acrylic resin, a methacrylic acid alkyl ester is preferable.
- alkyl methacrylates include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate.
- alkyl methacrylate having 1 to 8 carbon atoms in the alkyl group such as 2-hydroxyethyl methacrylate.
- the carbon number of the alkyl group contained in the methacrylic acid alkyl ester is preferably 1 to 4.
- methacrylic acid esters may be used alone or in combination of two or more.
- Examples of the other polymerizable monomer that can constitute the (meth) acrylic resin include acrylic acid esters and other compounds having a polymerizable carbon-carbon double bond in the molecule. Other polymerizable monomers may be used alone or in combination of two or more.
- an acrylic acid alkyl ester is preferable.
- alkyl acrylate esters include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, and cyclohexyl acrylate.
- alkyl acrylates having an alkyl group having 1 to 8 carbon atoms such as 2-hydroxyethyl acrylate.
- the number of carbon atoms of the alkyl group contained in the alkyl acrylate is preferably 1 to 4.
- acrylic acid esters may be used alone or in combination of two or more.
- the compound having a polymerizable carbon-carbon double bond in the molecule examples include vinyl compounds such as ethylene, propylene and styrene, and vinylcyan compounds such as acrylonitrile.
- vinyl compounds having a polymerizable carbon-carbon double bond in the molecule may be used alone or in combination of two or more.
- the first and second thermoplastic resin films 20 and 30 can be protective films for protecting the polarizing film 10 laminated and bonded to one surface of the polarizing film 10.
- the 1st or 2nd thermoplastic resin films 20 and 30 can also be a protective film which has optical functions like a phase difference film and a brightness enhancement film.
- a retardation provided with an arbitrary retardation value by stretching such as uniaxial stretching or biaxial stretching
- the first and / or second thermoplastic resin films 20 and 30 are laminated on the surface thereof, such as a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, and an antifouling layer (coating). Layer).
- the thickness of the first and second thermoplastic resin films 20 and 30 is usually 1 to 100 ⁇ m, but is preferably 5 to 60 ⁇ m and more preferably 5 to 50 ⁇ m from the viewpoint of strength and handleability. If it is the thickness in this range, the polarizing film 10 can be protected mechanically and shrinkage
- the polarizing plate 2 is more likely to curl in the sheet, but according to the present invention, the first thermoplastic resin film 20 or Even if the thickness of the second thermoplastic resin film 30 is as thin as 40 ⁇ m or less, further 30 ⁇ m or less, and a reverse curl is generated when the polarizing plate 2 is a sheet, the reverse curl is directed in the normal curl direction. It can be corrected effectively.
- thermoplastic resin film 20 is provided on one surface of the polarizing film 10 and the second thermoplastic resin film 30 is provided on the other surface, like the polarizing plates 2a and 2c shown in FIGS.
- the first thermoplastic resin film 20 and the second thermoplastic resin film 30 may be made of the same kind of thermoplastic resin or may be made of different kinds of thermoplastic resins, but different kinds of heat.
- the equilibrium moisture content and moisture permeability of the thermoplastic resin films to be bonded to both surfaces are different from each other, such as when composed of a plastic resin, curling is particularly likely to occur in the sheet of polarizing plate 2, In such a case, the present invention is particularly advantageous.
- thermoplastic resin film 20 a film having a higher equilibrium moisture content than the second thermoplastic resin film 30 can be used as the first thermoplastic resin film 20.
- the polarizing plate 2 is more likely to curl in the sheet.
- the difference in the equilibrium moisture content is 0.5% by weight or more, further 1% by weight or more, and even more preferably 1.5% by weight or more, and the polarizing plate 2 is a sheet. Even if a reverse curl is generated, the reverse curl can be effectively corrected in the normal curl direction.
- the film weight before the drying treatment is the weight after the film is stored for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 55%, and the drying means a treatment of drying the film at 105 ° C. for 2 hours.
- thermoplastic resin films having a difference in equilibrium moisture content of 0.5% by weight or more include, for example, a combination of a cellulose resin film (TAC film, etc.) and a cyclic polyolefin resin film, and a cellulose resin film (TAC). Film) and a (meth) acrylic resin film, a cellulose resin film (TAC film, etc.) and a polyester resin film, a cellulose resin film (TAC film, etc.) and a chain polyolefin resin film, A combination of (meth) acrylic resin film and cyclic polyolefin resin, a combination of (meth) acrylic resin film and polyester resin film, and the like.
- the difference in equilibrium moisture content between the first thermoplastic resin film 10 and the second thermoplastic resin film 20 is usually 5% by weight or less.
- the equilibrium moisture content of the first thermoplastic resin film 20 is, for example, 1.5% by weight or more, and may be 2% by weight or more.
- the equilibrium moisture content of the first thermoplastic resin film 20 is usually 5% by weight or less.
- the equilibrium moisture content of the second thermoplastic resin film 20 is usually 0.1 to 1.5. % By weight, preferably 0.1 to 1% by weight.
- the thermoplastic resin constituting the second thermoplastic resin film 20 that can achieve such an equilibrium moisture content include a cyclic polyolefin resin, a (meth) acrylic resin, a polyester resin, a chain polyolefin resin, and the like.
- the equilibrium moisture content of a thermoplastic resin film is the material (type of thermoplastic resin constituting the film), the thickness of the film, and the presence or material of a surface treatment layer (coating layer) that can be attached to the film surface. Can also be adjusted.
- the protect film 1 is disposed on the first thermoplastic resin film 20 side in the polarizing plate 2.
- the first thermoplastic resin film 20 a film having a moisture permeability higher than that of the second thermoplastic resin film 30 can be used.
- the difference in moisture permeability is 30 g / (m 2 ⁇ 24 hr) or more, further 50 g / (m 2 ⁇ 24 hr) or more, and even more preferably 100 g / (m 2 ⁇ 24 hr) or more. Even if a reverse curl is generated when the plate 2 is a sheet, the reverse curl can be effectively corrected in the normal curl direction.
- the moisture permeability of the film is a moisture permeability at a temperature of 40 ° C. and a relative humidity of 90% measured by a cup method defined in JIS Z 0208.
- combinations of thermoplastic resin films having a difference in moisture permeability of 30 g / (m 2 ⁇ 24 hr) or more include, for example, combinations of cellulose resin films (TAC films, etc.) and cyclic polyolefin resin films, cellulose resin films (TAC film, etc.) and (meth) acrylic resin film, cellulose resin film (TAC film, etc.) and polyester resin film, cellulose resin film (TAC film, etc.) and chain polyolefin resin
- the combination with a film, the combination of a (meth) acrylic-type resin film and cyclic polyolefin-type resin, the combination of a (meth) acrylic-type resin film and a polyester-type resin film, etc. can be mentioned.
- the moisture permeability of the first thermoplastic resin film 20 is, for example, 300 g / (m 2 ⁇ 24 hr) or more, and may be 400 g / (m 2 ⁇ 24 hr) or more.
- the moisture permeability of 300 g / (m 2 ⁇ 24 hr) or more means that when the first thermoplastic resin film 20 and the polarizing film 10 are bonded using an aqueous adhesive, the layer made of the aqueous adhesive is efficient. It is also advantageous in that it can be dried well and productivity can be improved.
- the moisture permeability of the first thermoplastic resin film 20 is usually 5000 g / (m 2 ⁇ 24 hr) or less.
- the moisture permeability of the second thermoplastic resin film 20 is usually 1 to 350 g / (m 2 ⁇ 24 hr. And preferably 5 to 200 g / (m 2 ⁇ 24 hr).
- the thermoplastic resin constituting the second thermoplastic resin film 20 that can achieve such moisture permeability are a cyclic polyolefin resin, a (meth) acrylic resin, a polyester resin, a chain polyolefin resin, and the like.
- the moisture permeability of a thermoplastic resin film depends on the material (type of thermoplastic resin constituting the film), the thickness of the film, the presence or absence of a surface treatment layer (coating layer) that can be attached to the film surface, and the material. Can also be adjusted.
- the protect film 1 is disposed on the first thermoplastic resin film 20 side in the polarizing plate 2.
- the polarizing film 10 and the first and second thermoplastic resin films 20 and 30 can be bonded using an adhesive.
- plasma Prior to laminating and bonding the first and second thermoplastic resin films 20 and 30 to the polarizing film 10, plasma is applied to the bonding surfaces of the polarizing film 10 and / or the first and second thermoplastic resin films 20 and 30.
- Surface activation treatment such as treatment, corona treatment, ultraviolet irradiation treatment, flame (flame) treatment, and saponification treatment may be performed. By this surface activation treatment, the adhesion between the polarizing film 10 and the first and second thermoplastic resin films 20 and 30 can be enhanced.
- a water-based adhesive, an active energy ray-curable adhesive, or a thermosetting adhesive can be used, and a water-based adhesive and an active energy ray-curable adhesive are preferable.
- the adhesive on both surfaces may be the same type of adhesive or different types of adhesive.
- the polarizing plate 2 is likely to curl in the sheet, but according to the present invention, when the polarizing plate 2 is made into a sheet by using different types of adhesive. Even if the reverse curl is generated, the reverse curl can be effectively corrected in the normal curl direction.
- a water-based adhesive is one in which an adhesive component is dissolved in water or dispersed in water.
- the aqueous adhesive preferably used is, for example, an adhesive composition using a polyvinyl alcohol resin or a urethane resin as a main component.
- the polyvinyl alcohol-based resin can be a polyvinyl alcohol resin such as partially saponified polyvinyl alcohol or fully saponified polyvinyl alcohol, or a carboxyl group-modified polyvinyl alcohol. Further, modified polyvinyl alcohol resins such as acetoacetyl group-modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, and amino group-modified polyvinyl alcohol may be used.
- Polyvinyl alcohol resins include vinyl alcohol homopolymers obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate, as well as copolymerization of vinyl acetate and other monomers copolymerizable therewith. It may be a polyvinyl alcohol copolymer obtained by saponifying the coalescence.
- An aqueous adhesive containing a polyvinyl alcohol resin as an adhesive component is usually an aqueous solution of a polyvinyl alcohol resin.
- concentration of the polyvinyl alcohol resin in the adhesive is usually 1 to 10 parts by weight, preferably 1 to 5 parts by weight with respect to 100 parts by weight of water.
- Adhesives composed of aqueous solutions of polyvinyl alcohol resins are used to improve adhesiveness, such as curable components such as polyhydric aldehydes, melamine compounds, zirconia compounds, zinc compounds, glyoxal, glyoxal derivatives, and water-soluble epoxy resins. It is preferable to contain a crosslinking agent.
- water-soluble epoxy resins include polyamide polyamine epoxy resins obtained by reacting polychloroalkylenes such as diethylenetriamine and triethylenetetramine with polycarboxylic acid polyamines such as adipic acid and epichlorohydrin. Can be suitably used.
- the addition amount of the curable component or the crosslinking agent is less than 1 part by weight with respect to 100 parts by weight of the polyvinyl alcohol resin, the effect of improving the adhesiveness tends to be small, and the addition amount is polyvinyl.
- the adhesive layer tends to become brittle.
- a urethane resin used as the main component of the adhesive
- a mixture of a polyester ionomer type urethane resin and a compound having a glycidyloxy group can be given.
- the polyester ionomer type urethane resin is a urethane resin having a polyester skeleton, into which a small amount of an ionic component (hydrophilic component) is introduced.
- Such an ionomer-type urethane resin is suitable as a water-based adhesive because it is emulsified directly in water without using an emulsifier to form an emulsion.
- a drying step for removing water contained in the aqueous adhesive is performed. It is preferable to implement. After the drying process, for example, a curing process for curing at a temperature of 20 to 45 ° C. may be provided.
- the active energy ray-curable adhesive is an adhesive that is cured by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays.
- active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays.
- the adhesive layer included in the polarizing plate 2 is a cured product layer of the adhesive.
- the active energy ray curable adhesive can be an adhesive containing an epoxy compound that is cured by cationic polymerization as a curable component, and preferably an ultraviolet curable adhesive containing such an epoxy compound as a curable component. It is an agent.
- the epoxy compound here means a compound having an average of 1 or more, preferably 2 or more epoxy groups in the molecule.
- the epoxy compound may be used alone or in combination of two or more.
- the active energy ray-curable adhesive can contain a radically polymerizable (meth) acrylic compound as a curable component, instead of or together with the epoxy compound.
- the (meth) acrylic compound is a (meth) acrylate monomer having at least one (meth) acryloyloxy group in the molecule; obtained by reacting two or more functional group-containing compounds, and at least two in the molecule.
- (meth) acryloyloxy group-containing compounds such as (meth) acrylate oligomers having (meth) acryloyloxy groups.
- the active energy ray-curable adhesive contains an epoxy compound that is cured by cationic polymerization as a curable component, it preferably contains a photocationic polymerization initiator.
- the photocationic polymerization initiator include aromatic diazonium salts; onium salts such as aromatic iodonium salts and aromatic sulfonium salts; iron-allene complexes.
- the active energy ray-curable adhesive contains a radical polymerizable curable component such as a (meth) acrylic compound, it is preferable to contain a photo radical polymerization initiator.
- photo radical polymerization initiator examples include acetophenone initiator, benzophenone initiator, benzoin ether initiator, thioxanthone initiator, xanthone, fluorenone, camphorquinone, benzaldehyde, anthraquinone and the like.
- an active energy ray-curable adhesive is used for laminating and laminating the polarizing film 10 and the first and / or second thermoplastic resin films 20 and 30, a drying process is performed as necessary after laminating and laminating. Then, a curing step of curing the active energy ray-curable adhesive by irradiating the active energy rays is performed.
- the light source of the active energy ray is not particularly limited, but ultraviolet light having a light emission distribution at a wavelength of 400 nm or less is preferable.
- the low pressure mercury lamp, the medium pressure mercury lamp, the high pressure mercury lamp, the ultrahigh pressure mercury lamp, the chemical lamp, the black light lamp, the micro A wave excitation mercury lamp, a metal halide lamp, etc. can be used.
- the active energy ray irradiation intensity to the adhesive layer composed of the active energy ray-curable adhesive is appropriately determined depending on the composition of the adhesive, but the irradiation intensity in the wavelength region effective for activating the polymerization initiator is 0.1. It is preferably set to be ⁇ 6000 mW / cm 2 . When the irradiation intensity is 0.1 mW / cm 2 or more, the reaction time does not become too long, and when it is 6000 mW / cm 2 or less, the heat of the adhesive layer due to the heat radiated from the light source and the heat generated when the adhesive is cured. There is little possibility of causing yellowing or deterioration of the polarizing film 10.
- the irradiation time of the active energy ray is also appropriately determined depending on the composition of the adhesive, but is set so that the integrated light amount expressed as the product of the irradiation intensity and the irradiation time is 10 to 10,000 mJ / cm 2. Is preferred. When the integrated light amount is 10 mJ / cm 2 or more, a sufficient amount of active species derived from the polymerization initiator can be generated to advance the curing reaction more reliably, and when it is 10000 mJ / cm 2 or less, the irradiation time is long. The productivity of the polarizing plate 2 can be maintained without becoming too much.
- the polarizing plate 2 can include an adhesive layer 40.
- the pressure-sensitive adhesive layer 40 can be directly laminated on the surface of the first or second thermoplastic resin film 20, 30 or the polarizing film 10, and the polarizing plate 3 with a protective film is attached to an image display element (for example, a liquid crystal cell). Can be used to match.
- the pressure-sensitive adhesive layer 40 for bonding the polarizing plate 3 with a protective film to an image display element is the main surface (first main surface) of the polarizing plate on the side bonded to the image display element such as a liquid crystal cell. Surface) side.
- the polarizing plate 2 includes first and second thermoplastic resin films 20 and 30, and the first thermoplastic resin film 20 is a film having a higher equilibrium moisture content and / or moisture permeability than the second thermoplastic resin film 30. When used, the pressure-sensitive adhesive layer 40 can be disposed on the second thermoplastic resin film 30 side.
- the pressure-sensitive adhesive layer 40 can be composed of a pressure-sensitive adhesive composition containing a resin such as (meth) acrylic, rubber-based, urethane-based, ester-based, silicone-based, or polyvinylether-based as a main component (base polymer). .
- a resin such as (meth) acrylic, rubber-based, urethane-based, ester-based, silicone-based, or polyvinylether-based
- base polymer a resin
- the pressure-sensitive adhesive composition may be an active energy ray curable type or a thermosetting type.
- Examples of the (meth) acrylic resin used in the pressure-sensitive adhesive composition include butyl (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate.
- a polymer or copolymer having one or more (meth) acrylic acid esters as monomers is preferably used.
- the (meth) acrylic resin is preferably copolymerized with a polar monomer.
- polar monomers examples include (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, glycidyl ( Mention may be made of monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group and the like, such as (meth) acrylate.
- the pressure-sensitive adhesive composition may contain only the above base polymer, but usually further contains a crosslinking agent.
- a crosslinking agent a metal ion having a valence of 2 or more, which forms a carboxylic acid metal salt with a carboxyl group; a polyamine compound, which forms an amide bond with a carboxyl group; Examples thereof include epoxy compounds and polyols that form ester bonds with carboxyl groups; polyisocyanate compounds that form amide bonds with carboxyl groups. Of these, polyisocyanate compounds are preferred.
- the active energy ray-curable pressure-sensitive adhesive composition has a property of being cured by irradiation with active energy rays such as ultraviolet rays and electron beams, and has an adhesive property even before irradiation with active energy rays. It is a pressure-sensitive adhesive composition having such a property that it can be adhered to an adherend such as the like and can be cured by irradiation with active energy rays to adjust the adhesion.
- the active energy ray-curable pressure-sensitive adhesive composition is preferably ultraviolet curable.
- the active energy ray-curable pressure-sensitive adhesive composition further contains an active energy ray-polymerizable compound in addition to the base polymer and the crosslinking agent. Further, if necessary, a photopolymerization initiator, a photosensitizer and the like may be contained.
- Adhesive composition consists of fine particles for imparting light scattering properties, beads (resin beads, glass beads, etc.), glass fibers, resins other than base polymers, tackifiers, fillers (metal powder and other inorganic powders) Etc.), antioxidants, ultraviolet absorbers, dyes, pigments, colorants, antifoaming agents, corrosion inhibitors, photopolymerization initiators and the like.
- the pressure-sensitive adhesive layer 40 is obtained by applying an organic solvent dilution of the above-mentioned pressure-sensitive adhesive composition onto the pressure-sensitive adhesive layer-forming surface of the polarizing plate 2 (that is, the polarizing film 10 or the first or second thermoplastic resin film 20, 30). And can be formed by drying. Or after apply
- the thickness of the pressure-sensitive adhesive layer 40 is usually 1 to 40 ⁇ m, but is preferably 3 to 25 ⁇ m from the viewpoint of thinning the polarizing plate 2.
- the separate film 50 is a film that is attached to protect the surface of the adhesive layer 40 until it is attached to an image display element (for example, a liquid crystal cell).
- the separate film 50 is usually composed of a thermoplastic resin film that has been subjected to a release treatment on one side, and the release treatment surface is bonded to the adhesive layer 40.
- the thermoplastic resin constituting the separate film 50 can be, for example, a polyethylene resin such as polyethylene, a polypropylene resin such as polypropylene, a polyester resin such as polyethylene terephthalate or polyethylene naphthalate, and the like.
- the thickness of the separate film 50 is, for example, 10 to 100 ⁇ m.
- the polarizing plate 2 can contain other components other than those described above.
- other components include an optical layer or an optical film having an optical function other than the polarizing film 10, and specific examples thereof are optical films such as a retardation film and a brightness enhancement film.
- Other optical films can be laminated and bonded via a pressure-sensitive adhesive layer or an adhesive layer.
- the polarizing plate 2 can include a protective film different from the protective film 1 subjected to the pressing step.
- This protect film is disposed on one surface of the polarizing plate 2.
- the above description of the protect film 1 is cited.
- the polarizing plate 3 with a protective film can be obtained which is preferably flat without curling or having positive curl.
- a reverse curl (a curl having a convex main surface on which the protective film 1 is superimposed) is generated (further, it is a reverse curl). And is particularly advantageous for MD curl).
- the first thermoplastic resin film 20 and the second thermoplastic resin film 30 have different equilibrium moisture contents and / or different from each other.
- moisture permeability it is not limited to this, and reverse curl tends to occur, for example, when the polarizing plate 2 has an asymmetric layer structure with respect to the polarizing film 10.
- thermoplastic resin film such as a protective film
- an optical film such as a brightness enhancement film
- Configurations of the thermoplastic resin films (protective films, etc.) bonded to both surfaces of the polarizing film 10 are different from each other.
- thermoplastic resin film such as a protective film
- adhesive layers for bonding a thermoplastic resin film (such as a protective film) on both surfaces of the polarizing film 10 are formed from different types of adhesives
- E A configuration in which a thermoplastic resin film (protective film or the like) is bonded to both surfaces of the polarizing film 10 and another optical film is bonded to one thermoplastic resin film
- F Other than the polarizing film 10, the total number of films and layers on one side is different from the total number of films and layers on the other side.
- the production method according to the present invention may further include a step of cutting the polarizing plate 3 with the protective film obtained by the pressing step to obtain a sheet of the polarizing plate 3 with the protective film. It can.
- a commonly used cutting device such as a shear cutter can be used.
- the shape of the single wafer is not particularly limited, but is usually a rectangular shape, preferably a rectangular shape having a long side and a short side, and more preferably a rectangular shape.
- This sheet is usually cut so that a pair of opposing sides are parallel to MD and the remaining pair of opposing sides are parallel to TD, but each side is inclined from MD or TD. You may cut
- the length of the long side and the short side of the single wafer is not particularly limited, the long side is usually 50 mm or more and the short side is 30 mm or more. The curl is more likely to occur as the size of the sheet body increases. If the size (long side and / or short side) is too small, the curl problem itself is less likely to occur.
- Moisture permeability of film Moisture permeability [g / (m 2 ⁇ 24 hr)] at a temperature of 40 ° C. and a relative humidity of 90% was measured by a cup method defined in JIS Z 0208.
- Polarizing plate with protective film and curl amount of polarizing plate From the obtained polarizing plate with protective film, a rectangular test piece having an MD length of 300 mm ⁇ TD length of 200 mm was cut out at a temperature of 25 ° C. and a relative humidity of 55%. It was left in the environment for 24 hours. The test piece was placed on the reference surface (horizontal platform) with its concave surface up, that is, with the four edges raised. In this state, the height from the reference surface was measured for each of the four corners of the test piece, and the curl amount [mm] was obtained as an average of the heights of the four corners. When the curl amount is a positive value, it means that the first thermoplastic resin film side is concave (positive curl), and when it is a negative value, the second thermoplastic resin film side is concave. (Reverse curl).
- Example 1> (A) Production of Polarizing Film While continuously transporting a long polyvinyl alcohol film (average polymerization degree: about 2400, saponification degree: 99.9 mol% or more, thickness: 30 ⁇ m), it is about 4 times dry. The film was uniaxially stretched and immersed in pure water at 40 ° C. for 1 minute while maintaining the tension state, and then in an aqueous solution having a weight ratio of iodine / potassium iodide / water of 0.1 / 5/100 at 28 ° C. for 60 seconds. Soaked.
- thermoplastic resin film [Konica Minolta Opto Co., Ltd. TAC film “KC2UAW” Film with a coating layer, thickness: 32.4 ⁇ m, equilibrium moisture content: 1.9 wt%, moisture permeability: 455 g / (m 2 ⁇ 24 hr)] and a long second thermoplastic resin film [JSR Corporation ) Product name “FEKB015D3”, which is a cyclic polyolefin resin film manufactured in the following manner: thickness: 15.1 ⁇ m, equilibrium moisture content: 0.8 wt%, moisture permeability: 115 g / (m 2 ⁇ 24 hr)]
- the first thermoplastic resin is passed through the laminating roll while injecting an aqueous adhesive between the polarizing film and the first thermoplastic resin film and between the polarizing film and the second thermoplastic resin film.
- polyvinyl alcohol powder trade name “Gosefimer” manufactured by Nippon Synthetic Chemical Industry Co., Ltd., average polymerization degree 1100] was dissolved in hot water at 95 ° C., and the concentration was 3%.
- the thickness T 2 of the polarizing plate was 58.6 ⁇ m.
- the curl amount of the polarizing plate was measured according to the above method, it was -10 mm (reverse curl).
- the bonding roll that contacts the protective film 1 is made of SUS plated with chromium (hardness 100 °), and the bonding roll that contacts the polarizing plate 2 is made of NBR (nitrile rubber) [hardness 70 °]. It was.
- the pressure (nip pressure) given to the laminated body of a protective film and a polarizing plate by a bonding roll is 0.1 MPa, and this numerical value is substantially the same also in the following Examples and Comparative Examples.
- Table 1 shows the curl amount of the polarizing plate with a protective film.
- the bonding roll that contacts the protective film 1 is made of NBR (nitrile rubber) [hardness 70 °], and the bonding roll that contacts the polarizing plate 2 has chrome plating formed on SUS.
- a polarizing plate with a protective film was produced in the same manner as in Example 1 except that the thickness was 100 [hardness].
- Table 1 shows the curl amount of the polarizing plate with a protective film.
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Abstract
Provided is a production method for a polarizing plate having a protective film, said production method including a step in which a protective film is laminated on one surface of a polarizing plate and pressed by passing same between a pair of bonding rolls. In the pair of bonding rolls, the surface hardness H1 of the bonding roll that comes in contact with the protective film and the surface hardness H2 of the bonding roll that comes in contact with the polarizing plate, as measured by a type A durometer hardness tester specified under JIS K 6253, fulfil the relationship H1 > H2.
Description
本発明は、偏光板表面にプロテクトフィルムを積層してなるプロテクトフィルム付偏光板の製造方法に関する。
The present invention relates to a method for producing a polarizing plate with a protective film obtained by laminating a protective film on the surface of the polarizing plate.
近年、スマートフォンのようなモバイル端末は、デザインや携帯性の面から大画面化、スリム化が急速に進みつつある。限られた厚みで長時間の駆動を実現するために、使用される偏光板についても高輝度化、薄型軽量化が要望されている。
In recent years, mobile terminals such as smartphones are rapidly becoming larger and slimmer from the viewpoint of design and portability. In order to realize long-time driving with a limited thickness, the polarizing plate used is also required to have high brightness and thin and light weight.
偏光板としては従来、ポリビニルアルコール系樹脂からなる偏光フィルムにトリアセチルセルロース(TAC)からなる保護フィルムを接着剤により貼合したものが一般的に用いられている。しかし近年では、薄膜化、耐久性、コスト、生産性等の観点から、TAC以外の樹脂からなる保護フィルムも使用されるようになっている〔例えば、特開2004-245925号公報(特許文献1)〕。
Conventionally, a polarizing plate made of a polyvinyl alcohol resin and a protective film made of triacetyl cellulose (TAC) bonded with an adhesive is generally used as the polarizing plate. However, in recent years, a protective film made of a resin other than TAC has been used from the viewpoints of thinning, durability, cost, productivity, and the like [for example, Japanese Patent Application Laid-Open No. 2004-245925 (Patent Document 1). ]].
偏光板は、それが置かれる環境に敏感であり、環境条件によっては、弓なりに反る変形を生じやすい。本明細書では、この変形を「カール」ともいう。カールには、「正カール」及び「逆カール」の2種類がある。偏光板には、液晶セルなどの画像表示素子に貼合される側の第1主面と、これとは反対側の第2主面とが存在するところ、「正カール」とは第1主面側を凸とするカールであり、「逆カール」とは第2主面側を凸とするカールである。偏光板に逆カールが生じていると、これを粘着剤層を介して画像表示素子に貼合する際、貼合ミスを生じたり、粘着剤層と画像表示素子との界面に気泡が混入したりする不具合を起こしやすくなる。
The polarizing plate is sensitive to the environment in which it is placed, and depending on the environmental conditions, it tends to bend like a bow. In this specification, this deformation is also referred to as “curl”. There are two types of curls: “normal curls” and “reverse curls”. The polarizing plate has a first main surface on the side to be bonded to an image display element such as a liquid crystal cell and a second main surface opposite to the first main surface. The curl is convex on the surface side, and the “reverse curl” is the curl convex on the second main surface side. If reverse curling has occurred in the polarizing plate, when this is bonded to the image display element through the pressure-sensitive adhesive layer, a bonding error occurs, or bubbles are mixed into the interface between the pressure-sensitive adhesive layer and the image display element. It becomes easy to cause the trouble to do.
そこで本発明は、偏光板構造を含む光学部材であって、逆カールが十分に抑制された光学部材を製造することができる方法を提供することにある。
Therefore, an object of the present invention is to provide a method capable of manufacturing an optical member including a polarizing plate structure, in which reverse curl is sufficiently suppressed.
本発明者は、1)偏光板は通常、その表面を保護するための剥離可能なプロテクトフィルム(表面保護フィルムとも呼ばれる。)を貼着したプロテクトフィルム付偏光板として市場流通され、画像表示素子への貼合においても、多くの場合、プロテクトフィルム付偏光板の形態で貼合されること、及び2)従って、上記課題の解決のためには、プロテクトフィルム付偏光板として逆カールが十分に抑制されていればよい、との着想に基づき、さらに鋭意検討を重ねて本発明に到達した。すなわち、本発明は、以下に示すプロテクトフィルム付偏光板の製造方法を提供する。
The present inventor 1) The polarizing plate is usually marketed as a polarizing plate with a protective film to which a peelable protective film (also referred to as a surface protective film) for protecting the surface of the polarizing plate is attached. In many cases, bonding is performed in the form of a polarizing plate with a protective film, and 2) Therefore, in order to solve the above problems, reverse curling is sufficiently suppressed as a polarizing plate with a protective film. Based on the idea that it should have been done, the present invention has been reached through further intensive studies. That is, this invention provides the manufacturing method of the polarizing plate with a protective film shown below.
[1] 偏光板の片面にプロテクトフィルムを重ねて1対の貼合ロール間に通すことにより押圧する工程を含むプロテクトフィルム付偏光板の製造方法であって、
前記1対の貼合ロールにおいて、JIS K 6253に規定されるタイプAデュロメータ硬さ試験機により測定される、前記プロテクトフィルムに接触する貼合ロールの表面硬度H1と、前記偏光板に接触する貼合ロールの表面硬度H2とが、下記式(I):
H1>H2 (I)
の関係を満たす、製造方法。 [1] A method for producing a polarizing plate with a protective film, including a step of pressing a protective film on one side of the polarizing plate and pressing it between a pair of bonding rolls,
In the pair of bonding rolls, the surface hardness H 1 of the bonding roll contacting the protect film, measured by a type A durometer hardness tester defined in JIS K 6253, and contacting the polarizing plate. and the surface hardness of H 2 lamination rolls, the following formula (I):
H 1 > H 2 (I)
A manufacturing method that satisfies the above relationship.
前記1対の貼合ロールにおいて、JIS K 6253に規定されるタイプAデュロメータ硬さ試験機により測定される、前記プロテクトフィルムに接触する貼合ロールの表面硬度H1と、前記偏光板に接触する貼合ロールの表面硬度H2とが、下記式(I):
H1>H2 (I)
の関係を満たす、製造方法。 [1] A method for producing a polarizing plate with a protective film, including a step of pressing a protective film on one side of the polarizing plate and pressing it between a pair of bonding rolls,
In the pair of bonding rolls, the surface hardness H 1 of the bonding roll contacting the protect film, measured by a type A durometer hardness tester defined in JIS K 6253, and contacting the polarizing plate. and the surface hardness of H 2 lamination rolls, the following formula (I):
H 1 > H 2 (I)
A manufacturing method that satisfies the above relationship.
[2] 前記偏光板は、枚葉体としたときに、前記プロテクトフィルムが重ねられる側を凸とするカールを生じるものである、[1]に記載の製造方法。
[2] The manufacturing method according to [1], wherein when the polarizing plate is formed into a sheet, a curl having a convex side on which the protective film is superimposed is generated.
[3] 前記偏光板は、偏光フィルムと、その一方の面に積層される第1熱可塑性樹脂フィルムと、他方の面に積層される第2熱可塑性樹脂フィルムとを含む、[1]又は[2]に記載の製造方法。
[3] The polarizing plate includes a polarizing film, a first thermoplastic resin film laminated on one surface thereof, and a second thermoplastic resin film laminated on the other surface, [1] or [ 2].
[4] 前記第1熱可塑性樹脂フィルムは、前記第2熱可塑性樹脂フィルムよりも温度23℃、相対湿度55%での平衡水分率が高い、[3]に記載の製造方法。
[4] The manufacturing method according to [3], wherein the first thermoplastic resin film has a higher equilibrium moisture content at a temperature of 23 ° C. and a relative humidity of 55% than the second thermoplastic resin film.
[5] 前記第1熱可塑性樹脂フィルムと前記第2熱可塑性樹脂フィルムとは、前記平衡水分率の差が0.5重量%以上である、[4]に記載の製造方法。
[5] The manufacturing method according to [4], wherein the difference in equilibrium moisture content between the first thermoplastic resin film and the second thermoplastic resin film is 0.5% by weight or more.
[6] 前記プロテクトフィルムは、前記第1熱可塑性樹脂フィルム側に配置される、[3]~[5]のいずれかに記載の製造方法。
[6] The manufacturing method according to any one of [3] to [5], wherein the protective film is disposed on the first thermoplastic resin film side.
[7] 前記第1熱可塑性樹脂フィルムは、前記平衡水分率が1.5重量%以上である、[3]~[6]のいずれかに記載の製造方法。
[7] The manufacturing method according to any one of [3] to [6], wherein the first thermoplastic resin film has an equilibrium moisture content of 1.5% by weight or more.
[8] 前記偏光板の厚みが100μm以下である、[1]~[7]のいずれかに記載の製造方法。
[8] The manufacturing method according to any one of [1] to [7], wherein the polarizing plate has a thickness of 100 μm or less.
本発明によれば、逆カールが十分に抑制されたプロテクトフィルム付偏光板を製造することができる。このプロテクトフィルム付偏光板によれば、上記不具合を抑えて画像表示素子への貼合を生産性良く実施することが可能である。
According to the present invention, a polarizing plate with a protective film in which reverse curling is sufficiently suppressed can be manufactured. According to this polarizing plate with a protective film, it is possible to carry out the bonding to the image display element with high productivity while suppressing the above problems.
(1)押圧する工程
図1を参照して、本発明に係るプロテクトフィルム付偏光板の製造方法は、偏光板2の片面にプロテクトフィルム1を重ねて1対の貼合ロール5,5’間に通すことにより、プロテクトフィルム1と偏光板2との積層体を上下から押圧する工程を含み、当該工程によりプロテクトフィルム付偏光板3が製造される。通常、押圧する工程に供されるプロテクトフィルム1及び偏光板2はそれぞれ、図示しない繰出ロールから連続的に繰出されるとともに連続的に搬送されて、1対の貼合ロール5,5’間に導入される。プロテクトフィルム1及び偏光板2の搬送方向はフィルム長手方向であり、通常、両者の搬送方向は平行である。本明細書においてMDとは、フィルムの機械流れ方向、すなわちフィルムの長手方向を意味する。MDに直交する方向、すなわちフィルム幅方向を本明細書ではTDともいう。 (1) Step of pressing Referring to FIG. 1, the manufacturing method of a polarizing plate with a protective film according to the present invention is such that the protective film 1 is stacked on one side of the polarizingplate 2 and a pair of bonding rolls 5, 5 ′. The polarizing plate 3 with a protective film is manufactured by the said process including the process of pressing the laminated body of the protective film 1 and the polarizing plate 2 from the upper and lower sides. Usually, each of the protective film 1 and the polarizing plate 2 subjected to the pressing step is continuously fed from a feeding roll (not shown) and continuously conveyed, and between a pair of bonding rolls 5 and 5 ′. be introduced. The transport direction of the protective film 1 and the polarizing plate 2 is the film longitudinal direction, and the transport directions of both are usually parallel. In the present specification, MD means the machine flow direction of the film, that is, the longitudinal direction of the film. The direction orthogonal to MD, that is, the film width direction is also referred to as TD in this specification.
図1を参照して、本発明に係るプロテクトフィルム付偏光板の製造方法は、偏光板2の片面にプロテクトフィルム1を重ねて1対の貼合ロール5,5’間に通すことにより、プロテクトフィルム1と偏光板2との積層体を上下から押圧する工程を含み、当該工程によりプロテクトフィルム付偏光板3が製造される。通常、押圧する工程に供されるプロテクトフィルム1及び偏光板2はそれぞれ、図示しない繰出ロールから連続的に繰出されるとともに連続的に搬送されて、1対の貼合ロール5,5’間に導入される。プロテクトフィルム1及び偏光板2の搬送方向はフィルム長手方向であり、通常、両者の搬送方向は平行である。本明細書においてMDとは、フィルムの機械流れ方向、すなわちフィルムの長手方向を意味する。MDに直交する方向、すなわちフィルム幅方向を本明細書ではTDともいう。 (1) Step of pressing Referring to FIG. 1, the manufacturing method of a polarizing plate with a protective film according to the present invention is such that the protective film 1 is stacked on one side of the polarizing
上記1対の貼合ロールにおいて、JIS K 6253に規定されるタイプAデュロメータ硬さ試験機により測定される、前記プロテクトフィルム1に接触する貼合ロール5の表面硬度H1と、前記偏光板2に接触する貼合ロール5’の表面硬度H2とが、下記式(I):
H1>H2 (I)
の関係を満たす。 In the pair of bonding rolls, the surface hardness H 1 of thebonding roll 5 in contact with the protect film 1 and measured by a type A durometer hardness tester defined in JIS K 6253, and the polarizing plate 2 and the surface hardness of H 2 lamination rolls 5 'in contact with the following formula (I):
H 1 > H 2 (I)
Satisfy the relationship.
H1>H2 (I)
の関係を満たす。 In the pair of bonding rolls, the surface hardness H 1 of the
H 1 > H 2 (I)
Satisfy the relationship.
一対の貼合ロール5,5’の表面硬度が上記式(I)を満たすと、ニップ部において、表面硬度の大きい貼合ロール5が、硬度の小さい貼合ロール5’に食い込んだ状態でプロテクトフィルム1及び偏光板2を押圧するため、プロテクトフィルム1と偏光板2とは、プロテクトフィルム1が重ねられる主面が凹となる形状で貼合される。したがって、ニップ部を通過後のプロテクトフィルム付偏光板3では、偏光板2の形状を、プロテクトフィルム1が重ねられる主面が凹となる方向(すなわち、正カール方向)に矯正(カール矯正)することができる。よって、例えば、押圧する工程に供される偏光板2が、枚葉体としたときに逆カール(プロテクトフィルム1が重ねられる主面側を凸とするカール)を生じるものである場合、本発明によれば、この逆カールを正カール方向へ矯正することができ、その結果、枚葉体としたときに逆カールが十分に抑制されているか、カールを有さずフラットであるか、又は正カールを有するプロテクトフィルム付偏光板3を得ることができる。得られるプロテクトフィルム付偏光板3は、枚葉体としたときに、好ましくはカールを有さずフラットであるか、又は正カールを有している。
When the surface hardness of the pair of bonding rolls 5 and 5 ′ satisfies the above formula (I), the bonding roll 5 having a large surface hardness is protected in the state where the surface hardness of the bonding roll 5 ′ having a low hardness has bite into the nip portion. In order to press the film 1 and the polarizing plate 2, the protective film 1 and the polarizing plate 2 are bonded in a shape in which the main surface on which the protective film 1 is stacked is concave. Therefore, in the polarizing plate 3 with the protective film after passing through the nip portion, the shape of the polarizing plate 2 is corrected (curl correction) in a direction in which the main surface on which the protective film 1 is superimposed is concave (that is, the positive curl direction). be able to. Therefore, for example, when the polarizing plate 2 that is subjected to the pressing step is a sheet, if it causes reverse curl (curl having a convex main surface on which the protective film 1 is superimposed), the present invention. Therefore, the reverse curl can be corrected in the normal curl direction. As a result, the reverse curl is sufficiently suppressed when the sheet body is formed, is flat with no curl, or is normal. A polarizing plate 3 with a protective film having curl can be obtained. When the obtained polarizing plate 3 with a protective film is a sheet, it preferably has no curl and is flat or has a positive curl.
貼合ロール5の表面硬度H1は、例えば、90°~100°であり、95°~100°であってもよい。貼合ロール5’の表面硬度H2は、例えば、60°~90°であり、70°~80°であってもよい。貼合ロール5,5’の硬度は、JIS K 6253に規定されるタイプAデュロメータ硬さ試験機で測定することができる。市販の硬度計としては、例えばアスカ社製のゴム硬度計「Type-A」などが用いられる。具体的には、表面を棒のようなもので押しつけた時の、貼合ロールの表面の抵抗を硬度計で測定する。
The surface hardness H 1 of the bonding roll 5 is, for example, 90 ° to 100 °, and may be 95 ° to 100 °. The surface hardness of H 2 lamination rolls 5 'is, for example, a 60 ° ~ 90 °, may be 70 ° ~ 80 °. The hardness of the bonding rolls 5 and 5 ′ can be measured with a type A durometer hardness tester defined in JIS K 6253. As a commercially available hardness meter, for example, a rubber hardness meter “Type-A” manufactured by Asuka Corporation is used. Specifically, the resistance of the surface of the bonding roll when the surface is pressed with a stick or the like is measured with a hardness meter.
上記式(I)の関係は、貼合ロール5と貼合ロール5’のそれぞれ表面の材質を適宜選択することによって実現できる。ここで、貼合ロールの表面とは、貼合ロールのプロテクトフィルム又は偏光板に接する面から、貼合ロールの回転中心軸に向けて少なくとも5mmの深さまでのことを意味する。貼合ロール5,5’の各々は、すべて同一の材質から形成されていてもよいし、貼合ロールの表面の材質と、該表面の材質で被覆された貼合ロール内部の材質とが異なっていてもよい。
The relationship of the above formula (I) can be realized by appropriately selecting the material of the surface of each of the bonding roll 5 and the bonding roll 5 '. Here, the surface of the bonding roll means from the surface in contact with the protective film or polarizing plate of the bonding roll to a depth of at least 5 mm toward the rotation center axis of the bonding roll. Each of the bonding rolls 5 and 5 ′ may be formed of the same material, or the surface material of the bonding roll is different from the material inside the bonding roll covered with the surface material. It may be.
貼合ロール5と貼合ロール5’の材質の組み合わせ(以下、A/Bとは、貼合ロール5の表面の材質/貼合ロール5’の表面の材質を示す)としては、例えば、金属/ゴム、合金/ゴム、弾性金属/ゴム、ゴム/ゴム等が挙げられる。
As a combination of the material of the bonding roll 5 and the bonding roll 5 ′ (hereinafter, A / B indicates the surface material of the bonding roll 5 / the surface material of the bonding roll 5 ′), for example, metal / Rubber, alloy / rubber, elastic metal / rubber, rubber / rubber and the like.
前記金属としては、鉄、アルミ等を用いることができる。前記合金としては、ステンレスを用いることができ、好ましくはSUS304(18%のCrと8%のNiを含むステンレス鋼)を用いることができる。貼合ロールの材質を金属及び/又は合金とする場合には、耐食性や耐擦傷性の向上を目的としてクロムめっき、ニッケルめっき、DLC(ダイヤモンドライクカーボン)等の表面処理を施すことが好ましい。また、表面処理は単層でも良いし、複数層積層しても良い。
As the metal, iron, aluminum or the like can be used. As the alloy, stainless steel can be used, and preferably SUS304 (stainless steel containing 18% Cr and 8% Ni) can be used. When the material of the bonding roll is a metal and / or alloy, it is preferable to perform surface treatment such as chromium plating, nickel plating, DLC (diamond-like carbon) for the purpose of improving corrosion resistance and scratch resistance. Further, the surface treatment may be a single layer or a plurality of layers.
前記弾性金属とは、ゴムや油等の弾性体の表面が、厚み0.2~2mmの金属層で被覆された構造のものを意味する。弾性金属の最表面の金属層としてはニッケル、ステンレス等を用いることができる。弾性金属の最表面の金属層に対しても、耐食性や耐擦傷性の向上を目的として、クロムめっき、ニッケルめっき、DLC(ダイヤモンドライクカーボン)等の表面処理を施すことが好ましい。
The elastic metal means a structure in which the surface of an elastic body such as rubber or oil is covered with a metal layer having a thickness of 0.2 to 2 mm. As the metal layer on the outermost surface of the elastic metal, nickel, stainless steel or the like can be used. The metal layer on the outermost surface of the elastic metal is preferably subjected to a surface treatment such as chromium plating, nickel plating, or DLC (diamond-like carbon) for the purpose of improving corrosion resistance and scratch resistance.
前記ゴムとしては、NBR(ニトリルゴム)、タイタン、ウレタン、シリコン、EPDM(エチレン-プロピレン-ジエンゴム)等を用いることができ、好ましくは、NBR、タイタン、ウレタンを用いることができる。貼合ロール5と貼合ロール5’の表面の材質として共にゴムを使用する際には、貼合ロール5の表面硬度H1を90°~100°とし、貼合ロール5’の表面硬度H2を60°~90°とすることが好ましい。
As the rubber, NBR (nitrile rubber), Titan, urethane, silicon, EPDM (ethylene-propylene-diene rubber), and the like can be used, and preferably, NBR, Titan, and urethane can be used. Lamination rolls 5 and the lamination rolls 5 'when used together rubber as the material of the surface of the surface hardness H 1 of the lamination rolls 5 and 90 ° ~ 100 °, the lamination rolls 5' surface hardness H of the 2 is preferably 60 ° to 90 °.
貼合ロール5と貼合ロール5’の直径は50mm~300mmであることが好ましく、100mm~200mmであることがさらに好ましい。直径が50mmを下回る場合には逆カール矯正効果が強くなり、正カールが必要以上に大きくなる可能性が有る。直径が300mmを上回る場合には、ニップ部の曲率が小さくなり、十分な逆カール矯正効果が得られない虞がある。
The diameter of the bonding roll 5 and the bonding roll 5 'is preferably 50 mm to 300 mm, and more preferably 100 mm to 200 mm. When the diameter is less than 50 mm, the reverse curl correction effect becomes strong, and the normal curl may become larger than necessary. When the diameter exceeds 300 mm, the curvature of the nip portion becomes small, and there is a possibility that a sufficient reverse curl correction effect cannot be obtained.
ここでカールについて説明する。カールとは、偏光板2やプロテクトフィルム付偏光板3などの光学部材(光学フィルム)が弓なりに反る変形をいい、この変形は通常、光学部材の枚葉体において生じる。カールは、光学部材が薄膜になるほど生じやすい傾向にある。
Here I explain curl. Curling refers to a deformation in which an optical member (optical film) such as the polarizing plate 2 or the polarizing plate 3 with a protective film warps in a bow shape, and this deformation usually occurs in a sheet of the optical member. Curling tends to occur more easily as the optical member becomes thinner.
カールは、光学部材が有する対向する2つの主面のうちどちら側を凸にしてカールするかに応じて、「正カール」と「逆カール」の2種類に分類することができる。液晶セルなどの画像表示素子に貼合される側の主面を第1主面とし、これとは反対側の主面を第2主面とするとき、「正カール」とは第1主面側を凸とするカールであり、「逆カール」とは第2主面側を凸とするカールである。本発明に係る製造方法に供される偏光板2は、枚葉体としたときに、典型的には、逆カール(プロテクトフィルム1が重ねられる主面側を凸とするカール)を生じるものである。
The curl can be classified into two types, “normal curl” and “reverse curl”, depending on which one of the two opposing main surfaces of the optical member is convex and curled. When the main surface on the side to be bonded to the image display element such as a liquid crystal cell is the first main surface and the main surface on the opposite side is the second main surface, the “normal curl” is the first main surface. The curl is convex on the side, and “reverse curl” is the curl convex on the second main surface side. When the polarizing plate 2 provided for the production method according to the present invention is made into a sheet, it typically produces reverse curl (curl having a convex main surface on which the protective film 1 is superimposed). is there.
またカールは、枚葉体である光学部材のどの端部(辺)に生じているかに応じて、「MDカール」と「TDカール」の2種類に分類することができる。図2を参照して、凸側の面を下にして平坦な台の上にカールした光学部材の枚葉体を置いたとき、「MDカール」とはMDにおける端部(典型的には両端部)が持ち上がるようなカールであり、「TDカール」とはTDにおける端部(典型的には両端部)が持ち上がるようなカールである。本発明に係る製造方法によれば、MDカール及びTDカールの両方を効果的に矯正することができる。
Also, the curl can be classified into two types, “MD curl” and “TD curl”, depending on which end (side) of the optical member which is a sheet. Referring to FIG. 2, when a curled optical member sheet is placed on a flat table with the convex side down, “MD curl” is the end of MD (typically both ends). The “TD curl” is a curl in which ends (typically both ends) in TD are lifted. According to the manufacturing method of the present invention, both MD curl and TD curl can be effectively corrected.
偏光板2やプロテクトフィルム付偏光板3などの光学部材が有し得るカールの評価(正カール、逆カール、MDカール、TDカールの種別の認定や、そのカール量)は、得られた光学部材から裁断した枚葉体について行う。この枚葉体は、対向する一対の辺がMDと平行であり、残りの対向する一対の辺がTDと平行である方形の枚葉体であり、MD長さは300mm、TD長さは200mmとする。
Evaluation of curl (optical curl, reverse curl, MD curl, TD curl type and amount of curl) that can be possessed by the optical member such as the polarizing plate 2 and the polarizing plate 3 with a protective film were obtained. This is done for single wafers cut from This sheet is a rectangular sheet having a pair of opposing sides parallel to the MD and the remaining pair of opposing sides parallel to the TD. The MD has a length of 300 mm and the TD has a length of 200 mm. And
本発明によれば、枚葉体としたときに逆カールが十分に抑制されている、好ましくはカールを有さずフラットであるか、又は正カールを有するプロテクトフィルム付偏光板3を得ることができる。このプロテクトフィルム付偏光板3によれば、粘着剤層を介して画像表示素子に貼合する際、貼合ミスを生じたり、粘着剤層と画像表示素子との界面に気泡が混入したりする不具合を効果的に抑制することができ、プロテクトフィルム付偏光板3と画像表示素子との貼合を生産性良く実施することができる。なお、プロテクトフィルム付偏光板3に生じているカールが正カールである分には、そのカール量が比較的大きくても、上記不具合及び生産性の点で特に問題はない。本発明により得られるプロテクトフィルム付偏光板3は、上記不具合を抑制できる(好ましくは上記不具合を生じない)程度において、逆カールを有していてもよい。
According to the present invention, it is possible to obtain the polarizing plate 3 with a protective film, which is sufficiently curled when it is made into a sheet, preferably flat without curling, or having normal curling. it can. According to this polarizing plate 3 with a protective film, when bonding to an image display element via an adhesive layer, a bonding error occurs or bubbles are mixed into the interface between the adhesive layer and the image display element. A malfunction can be suppressed effectively and pasting with polarizing plate 3 with a protective film and an image display element can be carried out with sufficient productivity. Note that the curl generated in the polarizing plate 3 with the protective film is a positive curl, and even if the curl amount is relatively large, there is no particular problem in terms of the above problems and productivity. The polarizing plate 3 with a protective film obtained by the present invention may have a reverse curl to the extent that the above problems can be suppressed (preferably not causing the above problems).
本発明による正カール方向への矯正量は、上記式(I)の左辺と右辺との差に依存し、この差が大きいほど矯正量は大きい傾向にある。押圧する工程に供される偏光板2が、枚葉体としたときにどの程度カールするものであるかにもよるが、得られるプロテクトフィルム付偏光板3を、逆カールを有するものではなく、フラットであるか、又は正カールを有するものとするために、上記押圧する工程を下記式(II):
H1-H2≧10 (II)
を満たす条件下で行うことが好ましい。押圧する工程に供される偏光板2が大きい逆カールを有する場合には、得られるプロテクトフィルム付偏光板3をフラットであるか、又は正カールを有するものとするために、上記式(II)の左辺を20より大きく(例えば30以上又は35以上に)しなければならないことがある。上記式(II)の左辺は、例えば40以下であってよい。 The correction amount in the positive curl direction according to the present invention depends on the difference between the left side and the right side of the formula (I), and the correction amount tends to increase as the difference increases. Depending on how much thepolarizing plate 2 subjected to the pressing step curls when it is made into a sheet, the obtained polarizing plate 3 with a protective film does not have reverse curl, In order to be flat or have a positive curl, the pressing step is represented by the following formula (II):
H 1 -H 2 ≧ 10 (II)
It is preferable to carry out under conditions that satisfy the above conditions. In the case where thepolarizing plate 2 subjected to the pressing step has a large reverse curl, in order to make the obtained polarizing plate 3 with a protective film flat or have a normal curl, the above formula (II) May have to be greater than 20 (for example, 30 or more or 35 or more). The left side of the formula (II) may be 40 or less, for example.
H1-H2≧10 (II)
を満たす条件下で行うことが好ましい。押圧する工程に供される偏光板2が大きい逆カールを有する場合には、得られるプロテクトフィルム付偏光板3をフラットであるか、又は正カールを有するものとするために、上記式(II)の左辺を20より大きく(例えば30以上又は35以上に)しなければならないことがある。上記式(II)の左辺は、例えば40以下であってよい。 The correction amount in the positive curl direction according to the present invention depends on the difference between the left side and the right side of the formula (I), and the correction amount tends to increase as the difference increases. Depending on how much the
H 1 -H 2 ≧ 10 (II)
It is preferable to carry out under conditions that satisfy the above conditions. In the case where the
偏光板2の片面に長尺のプロテクトフィルム1を重ねて1対の貼合ロール5,5’間に通すにあたっては、プロテクトフィルム1が有する粘着剤層が偏光板2の上記片面に接するように重ねられる。プロテクトフィルム1と偏光板2との積層に先立ち、プロテクトフィルム1の粘着剤層及び偏光板2の少なくともいずれか一方の貼合面にプラズマ処理、コロナ処理、紫外線照射処理、フレーム(火炎)処理、ケン化処理のような表面活性化処理を行ってもよい。
When the long protective film 1 is overlapped on one side of the polarizing plate 2 and passed between the pair of bonding rolls 5 and 5 ′, the adhesive layer of the protective film 1 is in contact with the one side of the polarizing plate 2. Overlaid. Prior to the lamination of the protective film 1 and the polarizing plate 2, plasma treatment, corona treatment, ultraviolet irradiation treatment, frame (flame) treatment is applied to at least one of the adhesive layer of the protective film 1 and the polarizing plate 2. A surface activation treatment such as a saponification treatment may be performed.
一対の貼合ロール5,5’により押圧する工程において、プロテクトフィルム1と偏光板2との積層体に与えられる圧力(ニップ圧)は、例えば0.01~1MPaであり、0.05~0.5MPaであってもよい。また、一対の貼合ロール5,5’により押圧する工程において、貼合ロール5と貼合ロール5’の接触する幅(ニップ幅)は、例えば1~20mmであり、5~15mmであってもよい。ニップ圧及びニップ幅が例示した範囲を下回る場合には、カール矯正効果が弱くなる虞がある。
In the step of pressing with the pair of bonding rolls 5 and 5 ′, the pressure (nip pressure) applied to the laminate of the protective film 1 and the polarizing plate 2 is, for example, 0.01 to 1 MPa, and 0.05 to 0. It may be 5 MPa. Further, in the step of pressing with the pair of bonding rolls 5 and 5 ′, the width (nip width) between the bonding roll 5 and the bonding roll 5 ′ is, for example, 1 to 20 mm, and 5 to 15 mm. Also good. When the nip pressure and the nip width are below the exemplified ranges, the curl correction effect may be weakened.
(2)プロテクトフィルム
プロテクトフィルム1は通常、基材フィルムと、その上に積層される粘着剤層とで構成される。プロテクトフィルム1は、偏光板2の表面を保護するためのフィルムであり、通常、例えば画像表示素子などにプロテクトフィルム付偏光板3が貼合された後にそれが有する粘着剤層ごと剥離除去される。基材フィルムは、熱可塑性樹脂、例えば、ポリエチレン系樹脂、ポリプロピレン系樹脂、環状ポリオレフィン系樹脂等のポリオレフィン系樹脂;ポリエチレンテレフタレート、ポリエチレンナフタレート等のポリエステル系樹脂;ポリカーボネート系樹脂;(メタ)アクリル系樹脂などで構成することができる。粘着剤層は、(メタ)アクリル系粘着剤、エポキシ系粘着剤、ウレタン系粘着剤及びシリコーン系粘着剤等で構成することが出来る。また、ポリプロピレン系樹脂及びポリエチレン系樹脂等の自己粘着性を有する樹脂層で構成することも出来る。 (2) Protect Film The protect film 1 is usually composed of a base film and an adhesive layer laminated thereon. The protective film 1 is a film for protecting the surface of thepolarizing plate 2, and usually, for example, after the polarizing plate 3 with a protective film is bonded to an image display element or the like, the entire adhesive layer that it has is peeled and removed. . The base film is a thermoplastic resin, for example, a polyolefin resin such as a polyethylene resin, a polypropylene resin, or a cyclic polyolefin resin; a polyester resin such as polyethylene terephthalate or polyethylene naphthalate; a polycarbonate resin; a (meth) acrylic resin It can be made of resin or the like. The pressure-sensitive adhesive layer can be composed of a (meth) acrylic pressure-sensitive adhesive, an epoxy-based pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, and the like. Moreover, it can also be comprised with the resin layer which has self-adhesiveness, such as a polypropylene-type resin and a polyethylene-type resin.
プロテクトフィルム1は通常、基材フィルムと、その上に積層される粘着剤層とで構成される。プロテクトフィルム1は、偏光板2の表面を保護するためのフィルムであり、通常、例えば画像表示素子などにプロテクトフィルム付偏光板3が貼合された後にそれが有する粘着剤層ごと剥離除去される。基材フィルムは、熱可塑性樹脂、例えば、ポリエチレン系樹脂、ポリプロピレン系樹脂、環状ポリオレフィン系樹脂等のポリオレフィン系樹脂;ポリエチレンテレフタレート、ポリエチレンナフタレート等のポリエステル系樹脂;ポリカーボネート系樹脂;(メタ)アクリル系樹脂などで構成することができる。粘着剤層は、(メタ)アクリル系粘着剤、エポキシ系粘着剤、ウレタン系粘着剤及びシリコーン系粘着剤等で構成することが出来る。また、ポリプロピレン系樹脂及びポリエチレン系樹脂等の自己粘着性を有する樹脂層で構成することも出来る。 (2) Protect Film The protect film 1 is usually composed of a base film and an adhesive layer laminated thereon. The protective film 1 is a film for protecting the surface of the
なお、本明細書において「(メタ)アクリル系樹脂」とは、アクリル系樹脂及びメタクリル系樹脂よりなる群から選ばれる少なくとも1種を表す。その他の「(メタ)」を付した用語においても同様である。
In this specification, “(meth) acrylic resin” represents at least one selected from the group consisting of acrylic resins and methacrylic resins. The same applies to other terms with “(meta)”.
プロテクトフィルム1の厚みT1は、例えば5~200μmであることができ、好ましくは10~150μmであり、より好ましくは20~120μmであり、さらに好ましくは25~100μm(例えば90μm以下)である。厚みT1が5μm未満の場合には、偏光板2の保護が不十分になることがあり、また取扱性の面でも不利である。さらに、強度が不十分となり、カール矯正効果が低減する可能性が有る。厚みT1が200μmを超えることは、コストや、プロテクトフィルム1のリワーク性の面で不利である。薄膜化の観点から、偏光板2を枚葉体とした際のカールをフラット又は正カールとするために偏光板を構成する偏光フィルム及び保護フィルムの厚みを調整することは困難であるが、プロテクトフィルムは通常、例えば画像表示素子などにプロテクトフィルム付偏光板3が貼合された後に剥離除去されるものであるため、カール矯正を目的として厚みを調整することが可能である。
The thickness T 1 of the protect film 1 can be, for example, 5 to 200 μm, preferably 10 to 150 μm, more preferably 20 to 120 μm, and further preferably 25 to 100 μm (for example, 90 μm or less). When the thickness T 1 is less than 5 μm, the protection of the polarizing plate 2 may be insufficient, and it is disadvantageous in terms of handleability. Furthermore, the strength is insufficient, and the curl correction effect may be reduced. The thickness T 1 exceeding 200 μm is disadvantageous in terms of cost and reworkability of the protective film 1. From the viewpoint of thinning, it is difficult to adjust the thickness of the polarizing film and the protective film constituting the polarizing plate in order to make the curl when the polarizing plate 2 is a single sheet into a flat or positive curl. Since the film is usually peeled and removed after the polarizing plate 3 with a protective film is bonded to, for example, an image display element, the thickness can be adjusted for the purpose of curl correction.
(3)偏光板
偏光板2は、少なくとも偏光フィルムを含む偏光素子であり、通常は偏光フィルムの少なくとも一方の面に積層される、保護フィルムなどの熱可塑性樹脂フィルムをさらに含む。保護フィルムは、偏光フィルムの保護を担う光学フィルムである。 (3) Polarizing plate Thepolarizing plate 2 is a polarizing element including at least a polarizing film, and further includes a thermoplastic resin film such as a protective film which is usually laminated on at least one surface of the polarizing film. A protective film is an optical film which bears protection of a polarizing film.
偏光板2は、少なくとも偏光フィルムを含む偏光素子であり、通常は偏光フィルムの少なくとも一方の面に積層される、保護フィルムなどの熱可塑性樹脂フィルムをさらに含む。保護フィルムは、偏光フィルムの保護を担う光学フィルムである。 (3) Polarizing plate The
(3-1)偏光板の構成例
偏光板2は、偏光フィルム及び保護フィルム以外の層又はフィルム、例えば偏光フィルム以外の他の光学機能を有する光学層又は光学フィルムを含むことができる。当該他の光学機能を有する光学層又は光学フィルムの例は、位相差フィルム(又は位相差層)、輝度向上フィルムなどである。保護フィルムを含む各種光学フィルムは、接着剤層又は粘着剤層を介して偏光フィルム上に積層貼合することができる。また偏光板2は、ハードコート層、防眩層、反射防止層、帯電防止層、防汚層のような表面処理層(コーティング層)を有していてもよい。 (3-1) Configuration Example of Polarizing Plate Thepolarizing plate 2 can include a layer or film other than the polarizing film and the protective film, for example, an optical layer or an optical film having an optical function other than the polarizing film. Examples of the optical layer or optical film having other optical functions include a retardation film (or retardation layer), a brightness enhancement film, and the like. Various optical films including a protective film can be laminated and bonded onto a polarizing film via an adhesive layer or a pressure-sensitive adhesive layer. The polarizing plate 2 may have a surface treatment layer (coating layer) such as a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, and an antifouling layer.
偏光板2は、偏光フィルム及び保護フィルム以外の層又はフィルム、例えば偏光フィルム以外の他の光学機能を有する光学層又は光学フィルムを含むことができる。当該他の光学機能を有する光学層又は光学フィルムの例は、位相差フィルム(又は位相差層)、輝度向上フィルムなどである。保護フィルムを含む各種光学フィルムは、接着剤層又は粘着剤層を介して偏光フィルム上に積層貼合することができる。また偏光板2は、ハードコート層、防眩層、反射防止層、帯電防止層、防汚層のような表面処理層(コーティング層)を有していてもよい。 (3-1) Configuration Example of Polarizing Plate The
偏光板2の厚みT2は、通常200μm以下であり、薄膜化の観点から、好ましくは125μm以下、より好ましくは100μm以下、さらに好ましくは75μm以下である。厚みT2が小さいほど偏光板2はその枚葉体においてカールを生じやすくなるが、本発明によれば、偏光板2の厚みT2が薄く、偏光板2が枚葉体としたときに逆カールを生じるものであっても、この逆カールを正カール方向へ効果的に矯正することができる。
The thickness T 2 of the polarizing plate 2 is usually 200 μm or less, and is preferably 125 μm or less, more preferably 100 μm or less, and even more preferably 75 μm or less from the viewpoint of thinning. The smaller the thickness T 2, the more easily the polarizing plate 2 is curled in the sheet. However, according to the present invention, when the polarizing plate 2 is thin and the polarizing plate 2 is a sheet, Even if the curl is generated, the reverse curl can be effectively corrected in the normal curl direction.
偏光板2の層構成の例を図3~図5を参照して説明するが、層構成はこれらの例に限定されるものではない。図3に示される偏光板2aは、偏光フィルム10;偏光フィルム10の一方の面に貼合される第1熱可塑性樹脂フィルム20;偏光フィルム10の他方の面に貼合される第2熱可塑性樹脂フィルム30;第2熱可塑性樹脂フィルム30の外面に積層される粘着剤層40;粘着剤層40の外面に積層されるセパレートフィルム50を含む。セパレートフィルム50は、粘着剤層40の表面(外面)を保護するための剥離可能なフィルムである。第1及び第2熱可塑性樹脂フィルム20,30は、例えば保護フィルムである。
Examples of the layer configuration of the polarizing plate 2 will be described with reference to FIGS. 3 to 5, but the layer configuration is not limited to these examples. The polarizing plate 2a shown in FIG. 3 includes a polarizing film 10; a first thermoplastic resin film 20 bonded to one surface of the polarizing film 10, and a second thermoplastic material bonded to the other surface of the polarizing film 10. A resin film 30; an adhesive layer 40 laminated on the outer surface of the second thermoplastic resin film 30; and a separate film 50 laminated on the outer surface of the adhesive layer 40. The separate film 50 is a peelable film for protecting the surface (outer surface) of the pressure-sensitive adhesive layer 40. The first and second thermoplastic resin films 20 and 30 are, for example, protective films.
図4に示される偏光板2bのように、第1及び第2熱可塑性樹脂フィルム20,30の一方が省略されてもよい。偏光板2bにおいては第2熱可塑性樹脂フィルム30が省略されており、偏光フィルム10の外面(第1熱可塑性樹脂フィルム20が積層される面とは反対側の面)に直接、粘着剤層40が貼合されている。このような偏光フィルム10の一方の面のみに熱可塑性樹脂フィルムを有する偏光板は、偏光板の薄膜化に有利である。偏光フィルム10の一方の面のみに熱可塑性樹脂フィルムが積層される場合には偏光板2はその枚葉体においてカールを生じやすくなるが、本発明によれば、偏光フィルム10の一方の面のみに熱可塑性樹脂フィルムが積層貼合されることによって偏光板2が枚葉体としたときに逆カールを生じるものであっても、この逆カールを正カール方向へ効果的に矯正することができる。
As in the polarizing plate 2b shown in FIG. 4, one of the first and second thermoplastic resin films 20 and 30 may be omitted. In the polarizing plate 2b, the second thermoplastic resin film 30 is omitted, and the pressure-sensitive adhesive layer 40 is directly formed on the outer surface of the polarizing film 10 (the surface opposite to the surface on which the first thermoplastic resin film 20 is laminated). Is pasted. Such a polarizing plate having a thermoplastic resin film only on one surface of the polarizing film 10 is advantageous for thinning the polarizing plate. When the thermoplastic resin film is laminated only on one surface of the polarizing film 10, the polarizing plate 2 is likely to curl in the sheet, but according to the present invention, only one surface of the polarizing film 10 is present. Even if the thermoplastic resin film is laminated and bonded, the reverse curl can be effectively corrected in the normal curl direction even when the polarizing plate 2 forms a sheet. .
また図5に示される偏光板2cのように、粘着剤層40及びセパレートフィルム50が省略されてもよい。偏光板2は、上記押圧する工程に供されるプロテクトフィルム1とは異なるプロテクトフィルムをあらかじめ一方面に有していてもよい。この場合、得られるプロテクトフィルム付偏光板3は、両面にプロテクトフィルムを有する偏光板である。
Moreover, the adhesive layer 40 and the separate film 50 may be omitted as in the polarizing plate 2c shown in FIG. The polarizing plate 2 may have a protective film different from the protective film 1 used for the pressing step on one side in advance. In this case, the obtained polarizing plate 3 with a protective film is a polarizing plate having protective films on both sides.
図3~図5において図示を省略しているが、偏光フィルム10と第1及び第2熱可塑性樹脂フィルム20,30との貼合は、好ましくは接着剤を用いて行うことができる。
Although not shown in FIGS. 3 to 5, the polarizing film 10 and the first and second thermoplastic resin films 20 and 30 can be preferably bonded using an adhesive.
(3-2)偏光フィルム
偏光フィルム10は、一軸延伸されたポリビニルアルコール系樹脂フィルムに二色性色素を吸着配向させたものであることができる。ポリビニルアルコール系樹脂フィルムを構成するポリビニルアルコール系樹脂としては、ポリ酢酸ビニル系樹脂をケン化したものを用いることができる。ポリ酢酸ビニル系樹脂としては、酢酸ビニルの単独重合体であるポリ酢酸ビニルのほか、酢酸ビニルとこれに共重合可能な他の単量体との共重合体が例示される。酢酸ビニルに共重合可能な他の単量体としては、例えば、不飽和カルボン酸類、オレフィン類、ビニルエーテル類、不飽和スルホン酸類、アンモニウム基を有する(メタ)アクリルアミド類等が挙げられる。 (3-2) Polarizing Film Thepolarizing film 10 can be obtained by adsorbing and orienting a dichroic dye on a uniaxially stretched polyvinyl alcohol resin film. As the polyvinyl alcohol resin constituting the polyvinyl alcohol resin film, a saponified polyvinyl acetate resin can be used. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth) acrylamides having an ammonium group.
偏光フィルム10は、一軸延伸されたポリビニルアルコール系樹脂フィルムに二色性色素を吸着配向させたものであることができる。ポリビニルアルコール系樹脂フィルムを構成するポリビニルアルコール系樹脂としては、ポリ酢酸ビニル系樹脂をケン化したものを用いることができる。ポリ酢酸ビニル系樹脂としては、酢酸ビニルの単独重合体であるポリ酢酸ビニルのほか、酢酸ビニルとこれに共重合可能な他の単量体との共重合体が例示される。酢酸ビニルに共重合可能な他の単量体としては、例えば、不飽和カルボン酸類、オレフィン類、ビニルエーテル類、不飽和スルホン酸類、アンモニウム基を有する(メタ)アクリルアミド類等が挙げられる。 (3-2) Polarizing Film The
ポリビニルアルコール系樹脂のケン化度は、80.0~100.0モル%の範囲であることができるが、好ましくは90.0~100.0モル%の範囲であり、より好ましくは94.0~100.0モル%の範囲である。ケン化度が80.0モル%未満であると、得られる偏光板2の耐水性及び耐湿熱性が低下し得る。
The degree of saponification of the polyvinyl alcohol-based resin can be in the range of 80.0 to 100.0 mol%, preferably in the range of 90.0 to 100.0 mol%, more preferably 94.0. It is in the range of ˜100.0 mol%. When the saponification degree is less than 80.0 mol%, the water resistance and heat-and-moisture resistance of the obtained polarizing plate 2 may be lowered.
ケン化度とは、ポリビニルアルコール系樹脂の原料であるポリ酢酸ビニル系樹脂に含まれる酢酸基(アセトキシ基:-OCOCH3)がケン化工程により水酸基に変化した割合をユニット比(モル%)で表したものであり、下記式:
ケン化度(モル%)=100×(水酸基の数)/(水酸基の数+酢酸基の数)
で定義される。ケン化度は、JIS K 6726(1994)に準拠して求めることができる。ケン化度が高いほど、水酸基の割合が高いことを示しており、従って結晶化を阻害する酢酸基の割合が低いことを示している。 The degree of saponification is the unit ratio (mol%) of the ratio of acetate groups (acetoxy groups: —OCOCH 3 ) contained in polyvinyl acetate resin, which is a raw material for polyvinyl alcohol resins, to hydroxyl groups by the saponification process. The following formula:
Degree of saponification (mol%) = 100 × (number of hydroxyl groups) / (number of hydroxyl groups + number of acetate groups)
Defined by The saponification degree can be determined according to JIS K 6726 (1994). The higher the degree of saponification, the higher the proportion of hydroxyl groups, and thus the lower the proportion of acetate groups that inhibit crystallization.
ケン化度(モル%)=100×(水酸基の数)/(水酸基の数+酢酸基の数)
で定義される。ケン化度は、JIS K 6726(1994)に準拠して求めることができる。ケン化度が高いほど、水酸基の割合が高いことを示しており、従って結晶化を阻害する酢酸基の割合が低いことを示している。 The degree of saponification is the unit ratio (mol%) of the ratio of acetate groups (acetoxy groups: —OCOCH 3 ) contained in polyvinyl acetate resin, which is a raw material for polyvinyl alcohol resins, to hydroxyl groups by the saponification process. The following formula:
Degree of saponification (mol%) = 100 × (number of hydroxyl groups) / (number of hydroxyl groups + number of acetate groups)
Defined by The saponification degree can be determined according to JIS K 6726 (1994). The higher the degree of saponification, the higher the proportion of hydroxyl groups, and thus the lower the proportion of acetate groups that inhibit crystallization.
ポリビニルアルコール系樹脂の平均重合度は、好ましくは100~10000であり、より好ましくは1500~8000であり、さらに好ましくは2000~5000である。ポリビニルアルコール系樹脂の平均重合度もJIS K 6726(1994)に準拠して求めることができる。平均重合度が100未満では好ましい偏光性能を得ることが困難であり、10000超では溶媒への溶解性が悪化し、ポリビニルアルコール系樹脂フィルムの形成が困難となり得る。
The average degree of polymerization of the polyvinyl alcohol-based resin is preferably 100 to 10,000, more preferably 1500 to 8000, and further preferably 2000 to 5000. The average degree of polymerization of the polyvinyl alcohol resin can also be determined according to JIS K 6726 (1994). If the average degree of polymerization is less than 100, it is difficult to obtain a preferable polarizing performance, and if it exceeds 10,000, the solubility in a solvent is deteriorated, and it may be difficult to form a polyvinyl alcohol-based resin film.
偏光フィルム10に含有(吸着配向)される二色性色素は、ヨウ素又は二色性有機染料であることができる。二色性有機染料の具体例は、レッドBR、レッドLR、レッドR、ピンクLB、ルビンBL、ボルドーGS、スカイブルーLG、レモンイエロー、ブルーBR、ブルー2R、ネイビーRY、グリーンLG、バイオレットLB、バイオレットB、ブラックH、ブラックB、ブラックGSP、イエロー3G、イエローR、オレンジLR、オレンジ3R、スカーレットGL、スカーレットKGL、コンゴーレッド、ブリリアントバイオレットBK、スプラブルーG、スプラブルーGL、スプラオレンジGL、ダイレクトスカイブルー、ダイレクトファーストオレンジS、ファーストブラックを含む。二色性色素は、1種のみを単独で用いてもよいし、2種以上を併用してもよい。二色性色素は、好ましくはヨウ素である。
The dichroic dye contained (adsorption orientation) in the polarizing film 10 can be iodine or a dichroic organic dye. Specific examples of the dichroic organic dye include: Red BR, Red LR, Red R, Pink LB, Rubin BL, Bordeaux GS, Sky Blue LG, Lemon Yellow, Blue BR, Blue 2R, Navy RY, Green LG, Violet LB, Violet B, Black H, Black B, Black GSP, Yellow 3G, Yellow R, Orange LR, Orange 3R, Scarlet GL, Scarlet KGL, Congo Red, Brilliant Violet BK, Spura Blue G, Spura Blue GL, Spura Orange GL, Direct Includes Sky Blue, Direct First Orange S and First Black. A dichroic dye may be used individually by 1 type, and may use 2 or more types together. The dichroic dye is preferably iodine.
偏光フィルム10は、ポリビニルアルコール系樹脂フィルムを一軸延伸する工程;ポリビニルアルコール系樹脂フィルムを二色性色素で染色することにより、二色性色素を吸着させる工程;二色性色素が吸着されたポリビニルアルコール系樹脂フィルムを架橋処理する工程;及び、架橋処理後に水洗する工程、を経て製造することができる。
The polarizing film 10 is a step of uniaxially stretching a polyvinyl alcohol-based resin film; a step of adsorbing a dichroic dye by dyeing the polyvinyl alcohol-based resin film with a dichroic dye; a polyvinyl on which the dichroic dye is adsorbed It can be manufactured through a step of crosslinking the alcohol-based resin film; and a step of washing with water after the crosslinking treatment.
ポリビニルアルコール系樹脂フィルムは、上述したポリビニルアルコール系樹脂を製膜したものである。製膜方法は、特に限定されるものではなく、溶融押出法、溶剤キャスト法のような公知の方法を採用することができる。ポリビニルアルコール系樹脂フィルムの厚みは、例えば10~150μm程度であり、好ましくは50μm以下、より好ましくは35μm以下である。
The polyvinyl alcohol resin film is a film obtained by forming the polyvinyl alcohol resin described above. The film forming method is not particularly limited, and a known method such as a melt extrusion method or a solvent casting method can be employed. The thickness of the polyvinyl alcohol-based resin film is, for example, about 10 to 150 μm, preferably 50 μm or less, more preferably 35 μm or less.
ポリビニルアルコール系樹脂フィルムの一軸延伸は、二色性色素の染色前、染色と同時、又は染色の後に行うことができる。一軸延伸を染色の後で行う場合、この一軸延伸は、架橋処理の前又は架橋処理中に行ってもよい。また、これらの複数の段階で一軸延伸を行ってもよい。
The uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before, simultaneously with, or after the dyeing of the dichroic dye. When uniaxial stretching is performed after dyeing, this uniaxial stretching may be performed before or during the crosslinking treatment. Moreover, you may uniaxially stretch in these several steps.
一軸延伸にあたっては、周速の異なるロール間で一軸に延伸してもよいし、熱ロールを用いて一軸に延伸してもよい。また、一軸延伸は、大気中で延伸を行う乾式延伸であってもよいし、溶液中でポリビニルアルコール系樹脂フィルムの延伸を行う湿式延伸であってもよい。延伸倍率は通常、3~8倍程度である。
In the uniaxial stretching, rolls having different peripheral speeds may be uniaxially stretched or may be stretched uniaxially using a hot roll. The uniaxial stretching may be dry stretching in which stretching is performed in the air, or may be wet stretching in which a polyvinyl alcohol-based resin film is stretched in a solution. The draw ratio is usually about 3 to 8 times.
ポリビニルアルコール系樹脂フィルムを二色性色素で染色する方法としては、例えば、ポリビニルアルコール系樹脂フィルムを二色性色素が含有された水溶液(染色溶液)に浸漬する方法が採用される。ポリビニルアルコール系樹脂フィルムは、染色処理の前に水への浸漬処理(膨潤処理)を施しておくことが好ましい。
As a method of dyeing a polyvinyl alcohol resin film with a dichroic dye, for example, a method of immersing the polyvinyl alcohol resin film in an aqueous solution (dye solution) containing the dichroic dye is employed. The polyvinyl alcohol-based resin film is preferably subjected to an immersion treatment (swelling treatment) in water before the dyeing treatment.
二色性色素としてヨウ素を用いる場合は、通常、ヨウ素及びヨウ化カリウムを含有する水溶液に、ポリビニルアルコール系樹脂フィルムを浸漬して染色する方法が採用される。この染色水溶液におけるヨウ素の含有量は、水100重量部あたり通常0.01~1重量部である。また、ヨウ化カリウムの含有量は、水100重量部あたり通常0.5~20重量部である。染色水溶液の温度は、通常20~40℃程度である。
When iodine is used as the dichroic dye, a method of dyeing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide is usually employed. The iodine content in this dyeing aqueous solution is usually 0.01 to 1 part by weight per 100 parts by weight of water. The content of potassium iodide is usually 0.5 to 20 parts by weight per 100 parts by weight of water. The temperature of the dyeing aqueous solution is usually about 20 to 40 ° C.
一方、二色性色素として二色性有機染料を用いる場合は、通常、水溶性の二色性有機染料を含む染色水溶液に、ポリビニルアルコール系樹脂フィルムを浸漬して染色する方法が採用される。染色水溶液における二色性有機染料の含有量は、水100重量部あたり通常1×10-4~10重量部であり、好ましくは1×10-3~1重量部である。この染色水溶液は、硫酸ナトリウム等の無機塩を染色助剤として含有していてもよい。染色水溶液の温度は、通常20~80℃程度である。
On the other hand, when a dichroic organic dye is used as the dichroic dye, a method of dyeing a polyvinyl alcohol resin film by immersing it in a dyeing aqueous solution containing a water-soluble dichroic organic dye is usually employed. The content of the dichroic organic dye in the aqueous dyeing solution is usually 1 × 10 −4 to 10 parts by weight, preferably 1 × 10 −3 to 1 part by weight per 100 parts by weight of water. This dyeing aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing aid. The temperature of the dyeing aqueous solution is usually about 20 to 80 ° C.
二色性色素による染色後の架橋処理は、染色されたポリビニルアルコール系樹脂フィルムを架橋剤含有水溶液に浸漬することにより行うことができる。架橋剤の好適な例はホウ酸であるが、ホウ砂のようなホウ素化合物、グリオキザール、グルタルアルデヒド等の他の架橋剤を用いることもできる。架橋剤は1種のみを使用してもよいし、2種以上を併用してもよい。
The crosslinking treatment after dyeing with the dichroic dye can be performed by immersing the dyed polyvinyl alcohol resin film in an aqueous solution containing a crosslinking agent. A suitable example of the cross-linking agent is boric acid, but other cross-linking agents such as boron compounds such as borax, glyoxal, and glutaraldehyde can also be used. Only 1 type may be used for a crosslinking agent and it may use 2 or more types together.
架橋剤含有水溶液における架橋剤の量は、水100重量部あたり通常2~15重量部であり、好ましくは5~12重量部である。二色性色素としてヨウ素を用いる場合、この架橋剤含有水溶液はヨウ化カリウムを含有することが好ましい。架橋剤含有水溶液におけるヨウ化カリウムの量は、水100重量部あたり通常0.1~15重量部であり、好ましくは5~12重量部である。架橋剤含有水溶液の温度は、通常50℃以上であり、好ましくは50~85℃である。
The amount of the crosslinking agent in the aqueous solution containing the crosslinking agent is usually 2 to 15 parts by weight, preferably 5 to 12 parts by weight per 100 parts by weight of water. When iodine is used as the dichroic dye, the aqueous solution containing a crosslinking agent preferably contains potassium iodide. The amount of potassium iodide in the crosslinking agent-containing aqueous solution is usually 0.1 to 15 parts by weight, preferably 5 to 12 parts by weight per 100 parts by weight of water. The temperature of the aqueous solution containing a crosslinking agent is usually 50 ° C. or higher, preferably 50 to 85 ° C.
架橋処理後のポリビニルアルコール系樹脂フィルムは通常、水洗処理される。水洗処理は、例えば、架橋処理されたポリビニルアルコール系樹脂フィルムを水に浸漬することにより行うことができる。水洗処理における水の温度は通常、1~40℃程度である。
The polyvinyl alcohol resin film after the crosslinking treatment is usually washed with water. The water washing treatment can be performed, for example, by immersing the crosslinked polyvinyl alcohol resin film in water. The temperature of water in the water washing treatment is usually about 1 to 40 ° C.
水洗後に乾燥処理を施して、偏光フィルム10が得られる。乾燥処理は、熱風乾燥機による乾燥、熱ロールに接触させることによる乾燥、遠赤外線ヒーターによる乾燥などであることができる。乾燥処理の温度は、通常30~100℃程度であり、50~90℃が好ましい。
The polarizing film 10 is obtained by performing a drying process after washing with water. The drying treatment can be drying with a hot air dryer, drying by contacting with a hot roll, drying with a far infrared heater, and the like. The temperature for the drying treatment is usually about 30 to 100 ° C., preferably 50 to 90 ° C.
偏光フィルム10の厚みは、通常2~40μm程度である。偏光板2の薄膜化の観点から、偏光フィルム10の厚みは、好ましくは20μm以下であり、より好ましくは15μm以下であり、さらに好ましくは10μm以下である。偏光フィルム10の厚みが小さいほど偏光板2はその枚葉体においてカールを生じやすくなるが、本発明によれば、偏光フィルム10の厚みが小さく、偏光板2が枚葉体としたときに逆カールを生じるものであっても、この逆カールを正カール方向へ効果的に矯正することができる。
The thickness of the polarizing film 10 is usually about 2 to 40 μm. From the viewpoint of thinning the polarizing plate 2, the thickness of the polarizing film 10 is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less. As the thickness of the polarizing film 10 is smaller, the polarizing plate 2 is more likely to curl in the sheet. However, according to the present invention, when the polarizing film 10 is small and the polarizing plate 2 is a sheet, Even if the curl is generated, the reverse curl can be effectively corrected in the normal curl direction.
(3-3)第1及び第2熱可塑性樹脂フィルム
第1及び第2熱可塑性樹脂フィルム20,30は、それぞれ独立して、透光性を有する熱可塑性樹脂、好ましくは光学的に透明な熱可塑性樹脂で構成されるフィルムである。第1及び第2熱可塑性樹脂フィルム20,30を構成する熱可塑性樹脂は、例えば、鎖状ポリオレフィン系樹脂(ポリプロピレン系樹脂等)、環状ポリオレフィン系樹脂(ノルボルネン系樹脂等)のようなポリオレフィン系樹脂;トリアセチルセルロース、ジアセチルセルロースのようなセルロース系樹脂;ポリエチレンテレフタレート、ポリブチレンテレフタレートのようなポリエステル系樹脂;ポリカーボネート系樹脂;メタクリル酸メチル系樹脂のような(メタ)アクリル系樹脂;ポリスチレン系樹脂;ポリ塩化ビニル系樹脂;アクリロニトリル・ブタジエン・スチレン系樹脂;アクリロニトリル・スチレン系樹脂;ポリ酢酸ビニル系樹脂;ポリ塩化ビニリデン系樹脂;ポリアミド系樹脂;ポリアセタール系樹脂;変性ポリフェニレンエーテル系樹脂;ポリスルホン系樹脂;ポリエーテルスルホン系樹脂;ポリアリレート系樹脂;ポリアミドイミド系樹脂;ポリイミド系樹脂等であることができる。 (3-3) First and second thermoplastic resin films The first and second thermoplastic resin films 20 and 30 are each independently a light-transmitting thermoplastic resin, preferably optically transparent heat. It is a film composed of a plastic resin. The thermoplastic resin constituting the first and second thermoplastic resin films 20 and 30 is, for example, a polyolefin resin such as a chain polyolefin resin (polypropylene resin or the like) or a cyclic polyolefin resin (norbornene resin or the like). A cellulose resin such as triacetyl cellulose and diacetyl cellulose; a polyester resin such as polyethylene terephthalate and polybutylene terephthalate; a polycarbonate resin; a (meth) acrylic resin such as a methyl methacrylate resin; a polystyrene resin; Polyvinyl chloride resin; Acrylonitrile butadiene styrene resin; Acrylonitrile styrene resin; Polyvinyl acetate resin; Polyvinylidene chloride resin; Polyamide resin; Polyacetal resin; Modified polyphenylene Ether-based resins; polysulfone resins; poly (ether sulfone) resins; polyarylate resin; polyamideimide resin; may be a polyimide resin or the like.
第1及び第2熱可塑性樹脂フィルム20,30は、それぞれ独立して、透光性を有する熱可塑性樹脂、好ましくは光学的に透明な熱可塑性樹脂で構成されるフィルムである。第1及び第2熱可塑性樹脂フィルム20,30を構成する熱可塑性樹脂は、例えば、鎖状ポリオレフィン系樹脂(ポリプロピレン系樹脂等)、環状ポリオレフィン系樹脂(ノルボルネン系樹脂等)のようなポリオレフィン系樹脂;トリアセチルセルロース、ジアセチルセルロースのようなセルロース系樹脂;ポリエチレンテレフタレート、ポリブチレンテレフタレートのようなポリエステル系樹脂;ポリカーボネート系樹脂;メタクリル酸メチル系樹脂のような(メタ)アクリル系樹脂;ポリスチレン系樹脂;ポリ塩化ビニル系樹脂;アクリロニトリル・ブタジエン・スチレン系樹脂;アクリロニトリル・スチレン系樹脂;ポリ酢酸ビニル系樹脂;ポリ塩化ビニリデン系樹脂;ポリアミド系樹脂;ポリアセタール系樹脂;変性ポリフェニレンエーテル系樹脂;ポリスルホン系樹脂;ポリエーテルスルホン系樹脂;ポリアリレート系樹脂;ポリアミドイミド系樹脂;ポリイミド系樹脂等であることができる。 (3-3) First and second thermoplastic resin films The first and second
鎖状ポリオレフィン系樹脂としては、ポリエチレン樹脂、ポリプロピレン樹脂のような鎖状オレフィンの単独重合体のほか、2種以上の鎖状オレフィンからなる共重合体を挙げることができる。より具体的な例は、ポリプロピレン系樹脂(プロピレンの単独重合体であるポリプロピレン樹脂や、プロピレンを主体とする共重合体)、ポリエチレン系樹脂(エチレンの単独重合体であるポリエチレン樹脂や、エチレンを主体とする共重合体)を含む。
Examples of the chain polyolefin resin include a homopolymer of a chain olefin such as a polyethylene resin and a polypropylene resin, and a copolymer composed of two or more chain olefins. More specific examples include polypropylene resins (polypropylene resins that are homopolymers of propylene and copolymers mainly composed of propylene), polyethylene resins (polyethylene resins that are homopolymers of ethylene and ethylene mainly) A copolymer).
環状ポリオレフィン系樹脂は、環状オレフィンを重合単位として重合される樹脂の総称である。環状ポリオレフィン系樹脂の具体例を挙げれば、環状オレフィンの開環(共)重合体、環状オレフィンの付加重合体、環状オレフィンとエチレン、プロピレンのような鎖状オレフィンとの共重合体(代表的にはランダム共重合体)、及びこれらを不飽和カルボン酸やその誘導体で変性したグラフト重合体、並びにそれらの水素化物等である。中でも、環状オレフィンとしてノルボルネンや多環ノルボルネン系モノマー等のノルボルネン系モノマーを用いたノルボルネン系樹脂が好ましく用いられる。
Cyclic polyolefin-based resin is a general term for resins that are polymerized using cyclic olefins as polymerization units. Specific examples of cyclic polyolefin resins include ring-opening (co) polymers of cyclic olefins, addition polymers of cyclic olefins, copolymers of cyclic olefins and chain olefins such as ethylene and propylene (typically Are random copolymers), graft polymers obtained by modifying them with unsaturated carboxylic acids or derivatives thereof, and hydrides thereof. Among these, norbornene resins using norbornene monomers such as norbornene and polycyclic norbornene monomers as cyclic olefins are preferably used.
セルロース系樹脂とは、綿花リンタや木材パルプ(広葉樹パルプ、針葉樹パルプ)等の原料セルロースから得られるセルロースの水酸基における水素原子の一部又は全部がアセチル基、プロピオニル基及び/又はブチリル基で置換された、セルロース有機酸エステル又はセルロース混合有機酸エステルをいう。例えば、セルロースの酢酸エステル、プロピオン酸エステル、酪酸エステル、及びそれらの混合エステル等からなるものが挙げられる。中でも、トリアセチルセルロース、ジアセチルセルロース、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が好ましい。
Cellulosic resins are those in which some or all of the hydrogen atoms in the hydroxyl groups of cellulose obtained from raw material cellulose such as cotton linter and wood pulp (hardwood pulp, conifer pulp) are substituted with acetyl groups, propionyl groups and / or butyryl groups. Further, it refers to a cellulose organic acid ester or a cellulose mixed organic acid ester. For example, cellulose acetate, propionate, butyrate, and mixed esters thereof can be used. Among these, triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, and cellulose acetate butyrate are preferable.
ポリエステル系樹脂は、エステル結合を有する、上記セルロース系樹脂以外の樹脂であり、多価カルボン酸又はその誘導体と多価アルコールとの重縮合体からなるものが一般的である。多価カルボン酸又はその誘導体としては2価のジカルボン酸又はその誘導体を用いることができ、例えばテレフタル酸、イソフタル酸、ジメチルテレフタレート、ナフタレンジカルボン酸ジメチル等が挙げられる。多価アルコールとしては2価のジオールを用いることができ、例えばエチレングリコール、プロパンジオール、ブタンジオール、ネオペンチルグリコール、シクロヘキサンジメタノール等が挙げられる。好適なポリエステル系樹脂の例は、ポリエチレンテレフタレートを含む。
The polyester-based resin is a resin other than the above cellulose-based resin having an ester bond, and is generally made of a polycondensate of a polyvalent carboxylic acid or a derivative thereof and a polyhydric alcohol. As the polyvalent carboxylic acid or a derivative thereof, a divalent dicarboxylic acid or a derivative thereof can be used, and examples thereof include terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl naphthalenedicarboxylate. As the polyhydric alcohol, a divalent diol can be used, and examples thereof include ethylene glycol, propanediol, butanediol, neopentyl glycol, and cyclohexanedimethanol. Examples of suitable polyester-based resins include polyethylene terephthalate.
ポリカーボネート系樹脂は、カルボナート基を介してモノマー単位が結合された重合体からなるエンジニアリングプラスチックであり、高い耐衝撃性、耐熱性、難燃性、透明性を有する樹脂である。ポリカーボネート系樹脂は、光弾性係数を下げるためにポリマー骨格を修飾したような変性ポリカーボネートと呼ばれる樹脂や、波長依存性を改良した共重合ポリカーボネート等であってもよい。
Polycarbonate resin is an engineering plastic made of a polymer in which monomer units are bonded via a carbonate group, and is a resin having high impact resistance, heat resistance, flame retardancy, and transparency. The polycarbonate-based resin may be a resin called a modified polycarbonate in which the polymer skeleton is modified in order to lower the photoelastic coefficient, a copolymerized polycarbonate with improved wavelength dependency, or the like.
(メタ)アクリル系樹脂は、(メタ)アクリル系モノマー由来の構成単位を含む重合体である。該重合体は、典型的にはメタクリル酸エステルを含む重合体である。好ましくはメタクリル酸エステルに由来する構造単位の割合が、全構造単位に対して、50重量%以上含む重合体である。(メタ)アクリル系樹脂は、メタクリル酸エステルの単独重合体であってもよいし、他の重合性モノマー由来の構成単位を含む共重合体であってもよい。この場合、他の重合性モノマー由来の構成単位の割合は、好ましくは全構造単位に対して、50重量%以下である。
(Meth) acrylic resin is a polymer containing structural units derived from (meth) acrylic monomers. The polymer is typically a polymer containing a methacrylic acid ester. Preferably, it is a polymer in which the proportion of structural units derived from methacrylic acid esters is 50% by weight or more based on the total structural units. The (meth) acrylic resin may be a methacrylic acid ester homopolymer or a copolymer containing structural units derived from other polymerizable monomers. In this case, the proportion of structural units derived from other polymerizable monomers is preferably 50% by weight or less based on the total structural units.
(メタ)アクリル系樹脂を構成し得るメタクリル酸エステルとしては、メタクリル酸アルキルエステルが好ましい。メタクリル酸アルキルエステルとしては、メタクリル酸メチル、メタクリル酸エチル、メタクリル酸n-プロピル、メタクリル酸イソプロピル、メタクリル酸n-ブチル、メタクリル酸イソブチル、メタクリル酸t-ブチル、メタクリル酸2-エチルヘキシル、メタクリル酸シクロヘキシル、メタクリル酸2-ヒドロキシエチルのようなアルキル基の炭素数が1~8であるメタクリル酸アルキルエステルが挙げられる。メタクリル酸アルキルエステルに含まれるアルキル基の炭素数は、好ましくは1~4である。(メタ)アクリル系樹脂において、メタクリル酸エステルは、1種のみを単独で用いてもよいし2種以上を併用してもよい。
As the methacrylic acid ester that can constitute the (meth) acrylic resin, a methacrylic acid alkyl ester is preferable. Examples of alkyl methacrylates include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate. And alkyl methacrylate having 1 to 8 carbon atoms in the alkyl group such as 2-hydroxyethyl methacrylate. The carbon number of the alkyl group contained in the methacrylic acid alkyl ester is preferably 1 to 4. In the (meth) acrylic resin, methacrylic acid esters may be used alone or in combination of two or more.
(メタ)アクリル系樹脂を構成し得る上記他の重合性モノマーとしては、アクリル酸エステル、及びその他の分子内に重合性炭素-炭素二重結合を有する化合物を挙げることができる。他の重合性モノマーは、1種のみを単独で用いてもよいし2種以上を併用してもよい。アクリル酸エステルとしては、アクリル酸アルキルエステルが好ましい。アクリル酸アルキルエステルとしては、アクリル酸メチル、アクリル酸エチル、アクリル酸n-プロピル、アクリル酸イソプロピル、アクリル酸n-ブチル、アクリル酸イソブチル、アクリル酸t-ブチル、アクリル酸2-エチルヘキシル、アクリル酸シクロヘキシル、アクリル酸2-ヒドロキシエチルのようなアルキル基の炭素数が1~8であるアクリル酸アルキルエステルなどが挙げられる。アクリル酸アルキルエステルに含まれるアルキル基の炭素数は、好ましくは1~4である。(メタ)アクリル系樹脂において、アクリル酸エステルは、1種のみを単独で用いてもよいし2種以上を併用してもよい。
Examples of the other polymerizable monomer that can constitute the (meth) acrylic resin include acrylic acid esters and other compounds having a polymerizable carbon-carbon double bond in the molecule. Other polymerizable monomers may be used alone or in combination of two or more. As the acrylic acid ester, an acrylic acid alkyl ester is preferable. Examples of alkyl acrylate esters include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, and cyclohexyl acrylate. And alkyl acrylates having an alkyl group having 1 to 8 carbon atoms such as 2-hydroxyethyl acrylate. The number of carbon atoms of the alkyl group contained in the alkyl acrylate is preferably 1 to 4. In the (meth) acrylic resin, acrylic acid esters may be used alone or in combination of two or more.
その他の分子内に重合性炭素-炭素二重結合を有する化合物としては、エチレン、プロピレン、スチレン等のビニル系化合物や、アクリロニトリルのようなビニルシアン化合物が挙げられる。その他の分子内に重合性炭素-炭素二重結合を有する化合物は、1種のみを単独で用いてもよいし2種以上を併用してもよい。
Other examples of the compound having a polymerizable carbon-carbon double bond in the molecule include vinyl compounds such as ethylene, propylene and styrene, and vinylcyan compounds such as acrylonitrile. Other compounds having a polymerizable carbon-carbon double bond in the molecule may be used alone or in combination of two or more.
第1及び第2熱可塑性樹脂フィルム20,30は、偏光フィルム10の一方の面に積層貼合される、偏光フィルム10を保護するための保護フィルムであることができる。第1又は第2熱可塑性樹脂フィルム20,30は、位相差フィルム、輝度向上フィルムのような光学機能を併せ持つ保護フィルムであることもできる。例えば、上記材料からなる熱可塑性樹脂フィルムを延伸(一軸延伸又は二軸延伸等)したり、該フィルム上に液晶層等を形成したりすることにより、任意の位相差値が付与された位相差フィルムとすることができる。第1及び/又は第2熱可塑性樹脂フィルム20,30は、その表面に積層される、ハードコート層、防眩層、反射防止層、帯電防止層、防汚層のような表面処理層(コーティング層)を有していてもよい。
The first and second thermoplastic resin films 20 and 30 can be protective films for protecting the polarizing film 10 laminated and bonded to one surface of the polarizing film 10. The 1st or 2nd thermoplastic resin films 20 and 30 can also be a protective film which has optical functions like a phase difference film and a brightness enhancement film. For example, a retardation provided with an arbitrary retardation value by stretching (such as uniaxial stretching or biaxial stretching) a thermoplastic resin film made of the above materials or forming a liquid crystal layer or the like on the film. It can be a film. The first and / or second thermoplastic resin films 20 and 30 are laminated on the surface thereof, such as a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, and an antifouling layer (coating). Layer).
第1及び第2熱可塑性樹脂フィルム20,30の厚みは通常1~100μmであるが、強度や取扱性等の観点から5~60μmであることが好ましく、5~50μmであることがより好ましい。この範囲内の厚みであれば、偏光フィルム10を機械的に保護し、偏光板2が湿熱環境下に曝されたときの偏光フィルム10の収縮を抑制することができる。第1熱可塑性樹脂フィルム20や第2熱可塑性樹脂フィルム30の厚みが小さいほど偏光板2はその枚葉体においてカールを生じやすくなるが、本発明によれば、第1熱可塑性樹脂フィルム20や第2熱可塑性樹脂フィルム30の厚みが例えば40μm以下、さらには30μm以下と薄く、偏光板2が枚葉体としたときに逆カールを生じるものであっても、この逆カールを正カール方向へ効果的に矯正することができる。
The thickness of the first and second thermoplastic resin films 20 and 30 is usually 1 to 100 μm, but is preferably 5 to 60 μm and more preferably 5 to 50 μm from the viewpoint of strength and handleability. If it is the thickness in this range, the polarizing film 10 can be protected mechanically and shrinkage | contraction of the polarizing film 10 when the polarizing plate 2 is exposed to a wet heat environment can be suppressed. As the thickness of the first thermoplastic resin film 20 or the second thermoplastic resin film 30 is smaller, the polarizing plate 2 is more likely to curl in the sheet, but according to the present invention, the first thermoplastic resin film 20 or Even if the thickness of the second thermoplastic resin film 30 is as thin as 40 μm or less, further 30 μm or less, and a reverse curl is generated when the polarizing plate 2 is a sheet, the reverse curl is directed in the normal curl direction. It can be corrected effectively.
図3及び図5に示される偏光板2a,2cのように、偏光フィルム10の一方の面に第1熱可塑性樹脂フィルム20を備え、他方の面に第2熱可塑性樹脂フィルム30を備える場合において、第1熱可塑性樹脂フィルム20と第2熱可塑性樹脂フィルム30とは、同種の熱可塑性樹脂で構成されていてもよいし、異種の熱可塑性樹脂で構成されていてもよいが、異種の熱可塑性樹脂で構成されている場合など、両面に貼合される熱可塑性樹脂フィルムの平衡水分率や透湿度が互いに異なる場合には、偏光板2の枚葉体にカールがとりわけ発生しやすいため、このような場合に本発明はとりわけ有利である。
In the case where the first thermoplastic resin film 20 is provided on one surface of the polarizing film 10 and the second thermoplastic resin film 30 is provided on the other surface, like the polarizing plates 2a and 2c shown in FIGS. The first thermoplastic resin film 20 and the second thermoplastic resin film 30 may be made of the same kind of thermoplastic resin or may be made of different kinds of thermoplastic resins, but different kinds of heat. When the equilibrium moisture content and moisture permeability of the thermoplastic resin films to be bonded to both surfaces are different from each other, such as when composed of a plastic resin, curling is particularly likely to occur in the sheet of polarizing plate 2, In such a case, the present invention is particularly advantageous.
例えば、第1熱可塑性樹脂フィルム20として、第2熱可塑性樹脂フィルム30よりも平衡水分率が高いフィルムを用いることができる。偏光フィルム10の両面に貼合される第1熱可塑性樹脂フィルム20と第2熱可塑性樹脂フィルム30との平衡水分率の差が大きいほど偏光板2はその枚葉体においてカールを生じやすくなるが、本発明によれば、この平衡水分率の差が0.5重量%以上、さらには1重量%以上、なおさらには1.5重量%以上であり、偏光板2が枚葉体としたときに逆カールを生じるものであっても、この逆カールを正カール方向へ効果的に矯正することができる。
For example, a film having a higher equilibrium moisture content than the second thermoplastic resin film 30 can be used as the first thermoplastic resin film 20. Although the larger the difference in the equilibrium moisture content between the first thermoplastic resin film 20 and the second thermoplastic resin film 30 bonded to both surfaces of the polarizing film 10, the polarizing plate 2 is more likely to curl in the sheet. According to the present invention, when the difference in the equilibrium moisture content is 0.5% by weight or more, further 1% by weight or more, and even more preferably 1.5% by weight or more, and the polarizing plate 2 is a sheet. Even if a reverse curl is generated, the reverse curl can be effectively corrected in the normal curl direction.
本明細書においてフィルムの平衡水分率は乾燥重量法によって測定され、具体的には、下記式:
平衡水分率(重量%)={(乾燥処理前のフィルム重量-乾燥処理後のフィルム重量)/乾燥処理前のフィルム重量}×100
に従って求められる。ここで乾燥処理前のフィルム重量は温度23℃、相対湿度55%の環境下にフィルムを24時間保管した後の重量であり、乾燥とはフィルムを105℃で2時間乾燥させる処理をいう。平衡水分率の差が0.5重量%以上である熱可塑性樹脂フィルムの組み合わせとしては、例えば、セルロース系樹脂フィルム(TACフィルム等)と環状ポリオレフィン系樹脂フィルムとの組み合わせ、セルロース系樹脂フィルム(TACフィルム等)と(メタ)アクリル系樹脂フィルムとの組み合わせ、セルロース系樹脂フィルム(TACフィルム等)とポリエステル系樹脂フィルムとの組み合わせ、セルロース系樹脂フィルム(TACフィルム等)と鎖状ポリオレフィン系樹脂フィルムとの組み合わせ、(メタ)アクリル系樹脂フィルムと環状ポリオレフィン系樹脂との組み合わせ、(メタ)アクリル系樹脂フィルムとポリエステル系樹脂フィルムとの組み合わせ等を挙げることができる。第1熱可塑性樹脂フィルム10と第2熱可塑性樹脂フィルム20の平衡水分率の差は、通常5重量%以下である。 In the present specification, the equilibrium moisture content of the film is measured by a dry weight method, specifically, the following formula:
Equilibrium moisture content (% by weight) = {(film weight before drying treatment−film weight after drying treatment) / film weight before drying treatment} × 100
As required. Here, the film weight before the drying treatment is the weight after the film is stored for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 55%, and the drying means a treatment of drying the film at 105 ° C. for 2 hours. Examples of the combination of thermoplastic resin films having a difference in equilibrium moisture content of 0.5% by weight or more include, for example, a combination of a cellulose resin film (TAC film, etc.) and a cyclic polyolefin resin film, and a cellulose resin film (TAC). Film) and a (meth) acrylic resin film, a cellulose resin film (TAC film, etc.) and a polyester resin film, a cellulose resin film (TAC film, etc.) and a chain polyolefin resin film, A combination of (meth) acrylic resin film and cyclic polyolefin resin, a combination of (meth) acrylic resin film and polyester resin film, and the like. The difference in equilibrium moisture content between the firstthermoplastic resin film 10 and the second thermoplastic resin film 20 is usually 5% by weight or less.
平衡水分率(重量%)={(乾燥処理前のフィルム重量-乾燥処理後のフィルム重量)/乾燥処理前のフィルム重量}×100
に従って求められる。ここで乾燥処理前のフィルム重量は温度23℃、相対湿度55%の環境下にフィルムを24時間保管した後の重量であり、乾燥とはフィルムを105℃で2時間乾燥させる処理をいう。平衡水分率の差が0.5重量%以上である熱可塑性樹脂フィルムの組み合わせとしては、例えば、セルロース系樹脂フィルム(TACフィルム等)と環状ポリオレフィン系樹脂フィルムとの組み合わせ、セルロース系樹脂フィルム(TACフィルム等)と(メタ)アクリル系樹脂フィルムとの組み合わせ、セルロース系樹脂フィルム(TACフィルム等)とポリエステル系樹脂フィルムとの組み合わせ、セルロース系樹脂フィルム(TACフィルム等)と鎖状ポリオレフィン系樹脂フィルムとの組み合わせ、(メタ)アクリル系樹脂フィルムと環状ポリオレフィン系樹脂との組み合わせ、(メタ)アクリル系樹脂フィルムとポリエステル系樹脂フィルムとの組み合わせ等を挙げることができる。第1熱可塑性樹脂フィルム10と第2熱可塑性樹脂フィルム20の平衡水分率の差は、通常5重量%以下である。 In the present specification, the equilibrium moisture content of the film is measured by a dry weight method, specifically, the following formula:
Equilibrium moisture content (% by weight) = {(film weight before drying treatment−film weight after drying treatment) / film weight before drying treatment} × 100
As required. Here, the film weight before the drying treatment is the weight after the film is stored for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 55%, and the drying means a treatment of drying the film at 105 ° C. for 2 hours. Examples of the combination of thermoplastic resin films having a difference in equilibrium moisture content of 0.5% by weight or more include, for example, a combination of a cellulose resin film (TAC film, etc.) and a cyclic polyolefin resin film, and a cellulose resin film (TAC). Film) and a (meth) acrylic resin film, a cellulose resin film (TAC film, etc.) and a polyester resin film, a cellulose resin film (TAC film, etc.) and a chain polyolefin resin film, A combination of (meth) acrylic resin film and cyclic polyolefin resin, a combination of (meth) acrylic resin film and polyester resin film, and the like. The difference in equilibrium moisture content between the first
第1熱可塑性樹脂フィルム20の平衡水分率は、例えば1.5重量%以上であり、2重量%以上であってもよい。第1熱可塑性樹脂フィルム20の平衡水分率は、通常5重量%以下である。
The equilibrium moisture content of the first thermoplastic resin film 20 is, for example, 1.5% by weight or more, and may be 2% by weight or more. The equilibrium moisture content of the first thermoplastic resin film 20 is usually 5% by weight or less.
第1熱可塑性樹脂フィルム20として、第2熱可塑性樹脂フィルム30よりも平衡水分率が高いフィルムを用いる場合において、第2熱可塑性樹脂フィルム20の平衡水分率は、通常0.1~1.5重量%であり、好ましくは0.1~1重量%である。かかる平衡水分率を達成し得る第2熱可塑性樹脂フィルム20を構成する熱可塑性樹脂の例は、環状ポリオレフィン系樹脂、(メタ)アクリル系樹脂、ポリエステル系樹脂、鎖状ポリオレフィン系樹脂などである。
When a film having a higher equilibrium moisture content than the second thermoplastic resin film 30 is used as the first thermoplastic resin film 20, the equilibrium moisture content of the second thermoplastic resin film 20 is usually 0.1 to 1.5. % By weight, preferably 0.1 to 1% by weight. Examples of the thermoplastic resin constituting the second thermoplastic resin film 20 that can achieve such an equilibrium moisture content include a cyclic polyolefin resin, a (meth) acrylic resin, a polyester resin, a chain polyolefin resin, and the like.
熱可塑性樹脂フィルムの平衡水分率は、その材質(フィルムを構成する熱可塑性樹脂の種類)のほか、フィルムの厚み、フィルム表面に付設することができる表面処理層(コーティング層)の有無や材質などによっても調整することができる。
The equilibrium moisture content of a thermoplastic resin film is the material (type of thermoplastic resin constituting the film), the thickness of the film, and the presence or material of a surface treatment layer (coating layer) that can be attached to the film surface. Can also be adjusted.
第1熱可塑性樹脂フィルム20として、第2熱可塑性樹脂フィルム30よりも平衡水分率が高いフィルムを用いる場合、偏光板2に生じやすい逆カールを正カール方向に矯正するという観点から、通常は、上記押圧する工程においてプロテクトフィルム1は、偏光板2における第1熱可塑性樹脂フィルム20側に配置される。
When using a film having a higher equilibrium moisture content than the second thermoplastic resin film 30 as the first thermoplastic resin film 20, from the viewpoint of correcting the reverse curl that is likely to occur in the polarizing plate 2 in the normal curl direction, usually, In the pressing step, the protect film 1 is disposed on the first thermoplastic resin film 20 side in the polarizing plate 2.
また例えば、第1熱可塑性樹脂フィルム20として、第2熱可塑性樹脂フィルム30よりも透湿度が高いフィルムを用いることができる。偏光フィルム10の両面に貼合される第1熱可塑性樹脂フィルム20と第2熱可塑性樹脂フィルム30との透湿度の差が大きいほど偏光板2はその枚葉体においてカールを生じやすくなるが、本発明によれば、この透湿度の差が30g/(m2・24hr)以上、さらには50g/(m2・24hr)以上、なおさらには100g/(m2・24hr)以上であり、偏光板2が枚葉体としたときに逆カールを生じるものであっても、この逆カールを正カール方向へ効果的に矯正することができる。
Further, for example, as the first thermoplastic resin film 20, a film having a moisture permeability higher than that of the second thermoplastic resin film 30 can be used. The larger the difference in the water vapor transmission rate between the first thermoplastic resin film 20 and the second thermoplastic resin film 30 bonded to both surfaces of the polarizing film 10, the more easily the polarizing plate 2 curls in the sheet, According to the present invention, the difference in moisture permeability is 30 g / (m 2 · 24 hr) or more, further 50 g / (m 2 · 24 hr) or more, and even more preferably 100 g / (m 2 · 24 hr) or more. Even if a reverse curl is generated when the plate 2 is a sheet, the reverse curl can be effectively corrected in the normal curl direction.
本明細書においてフィルムの透湿度は、JIS Z 0208に規定されるカップ法により測定される温度40℃、相対湿度90%での透湿度である。透湿度の差が30g/(m2・24hr)以上である熱可塑性樹脂フィルムの組み合わせとしては、例えば、セルロース系樹脂フィルム(TACフィルム等)と環状ポリオレフィン系樹脂フィルムとの組み合わせ、セルロース系樹脂フィルム(TACフィルム等)と(メタ)アクリル系樹脂フィルムとの組み合わせ、セルロース系樹脂フィルム(TACフィルム等)とポリエステル系樹脂フィルムとの組み合わせ、セルロース系樹脂フィルム(TACフィルム等)と鎖状ポリオレフィン系樹脂フィルムとの組み合わせ、(メタ)アクリル系樹脂フィルムと環状ポリオレフィン系樹脂との組み合わせ、(メタ)アクリル系樹脂フィルムとポリエステル系樹脂フィルムとの組み合わせ等を挙げることができる。第1熱可塑性樹脂フィルム10と第2熱可塑性樹脂フィルム20の透湿度の差は、通常5000g/(m2・24hr)以下である。
In this specification, the moisture permeability of the film is a moisture permeability at a temperature of 40 ° C. and a relative humidity of 90% measured by a cup method defined in JIS Z 0208. Examples of combinations of thermoplastic resin films having a difference in moisture permeability of 30 g / (m 2 · 24 hr) or more include, for example, combinations of cellulose resin films (TAC films, etc.) and cyclic polyolefin resin films, cellulose resin films (TAC film, etc.) and (meth) acrylic resin film, cellulose resin film (TAC film, etc.) and polyester resin film, cellulose resin film (TAC film, etc.) and chain polyolefin resin The combination with a film, the combination of a (meth) acrylic-type resin film and cyclic polyolefin-type resin, the combination of a (meth) acrylic-type resin film and a polyester-type resin film, etc. can be mentioned. The difference in moisture permeability between the first thermoplastic resin film 10 and the second thermoplastic resin film 20 is usually 5000 g / (m 2 · 24 hr) or less.
第1熱可塑性樹脂フィルム20の透湿度は、例えば300g/(m2・24hr)以上であり、400g/(m2・24hr)以上であってもよい。透湿度が300g/(m2・24hr)以上であることは、水系接着剤を用いて第1熱可塑性樹脂フィルム20と偏光フィルム10とを貼合する場合において、水系接着剤からなる層を効率良く乾燥させることができ、生産性を高めることができる点でも有利である。第1熱可塑性樹脂フィルム20の透湿度は、通常5000g/(m2・24hr)以下である。
The moisture permeability of the first thermoplastic resin film 20 is, for example, 300 g / (m 2 · 24 hr) or more, and may be 400 g / (m 2 · 24 hr) or more. The moisture permeability of 300 g / (m 2 · 24 hr) or more means that when the first thermoplastic resin film 20 and the polarizing film 10 are bonded using an aqueous adhesive, the layer made of the aqueous adhesive is efficient. It is also advantageous in that it can be dried well and productivity can be improved. The moisture permeability of the first thermoplastic resin film 20 is usually 5000 g / (m 2 · 24 hr) or less.
第1熱可塑性樹脂フィルム20として、第2熱可塑性樹脂フィルム30よりも透湿度が高いフィルムを用いる場合において、第2熱可塑性樹脂フィルム20の透湿度は、通常1~350g/(m2・24hr)であり、好ましくは5~200g/(m2・24hr)である。かかる透湿度を達成し得る第2熱可塑性樹脂フィルム20を構成する熱可塑性樹脂の例は、環状ポリオレフィン系樹脂、(メタ)アクリル系樹脂、ポリエステル系樹脂、鎖状ポリオレフィン系樹脂などである。
In the case where a film having a higher moisture permeability than that of the second thermoplastic resin film 30 is used as the first thermoplastic resin film 20, the moisture permeability of the second thermoplastic resin film 20 is usually 1 to 350 g / (m 2 · 24 hr. And preferably 5 to 200 g / (m 2 · 24 hr). Examples of the thermoplastic resin constituting the second thermoplastic resin film 20 that can achieve such moisture permeability are a cyclic polyolefin resin, a (meth) acrylic resin, a polyester resin, a chain polyolefin resin, and the like.
熱可塑性樹脂フィルムの透湿度は、その材質(フィルムを構成する熱可塑性樹脂の種類)のほか、フィルムの厚み、フィルム表面に付設することができる表面処理層(コーティング層)の有無や材質などによっても調整することができる。
The moisture permeability of a thermoplastic resin film depends on the material (type of thermoplastic resin constituting the film), the thickness of the film, the presence or absence of a surface treatment layer (coating layer) that can be attached to the film surface, and the material. Can also be adjusted.
第1熱可塑性樹脂フィルム20として、第2熱可塑性樹脂フィルム30よりも透湿度が高いフィルムを用いる場合、偏光板2に生じやすい逆カールを正カール方向に矯正するという観点から、通常は、上記押圧する工程においてプロテクトフィルム1は、偏光板2における第1熱可塑性樹脂フィルム20側に配置される。
In the case of using a film having higher moisture permeability than the second thermoplastic resin film 30 as the first thermoplastic resin film 20, from the viewpoint of correcting the reverse curl that is likely to occur in the polarizing plate 2 in the normal curl direction, usually, In the pressing step, the protect film 1 is disposed on the first thermoplastic resin film 20 side in the polarizing plate 2.
上述のように、偏光フィルム10と、第1及び第2熱可塑性樹脂フィルム20,30とは、接着剤を用いて貼合することができる。偏光フィルム10に第1,第2熱可塑性樹脂フィルム20、30を積層貼合するに先立って、偏光フィルム10及び/又は第1,第2熱可塑性樹脂フィルム20、30の貼合面に、プラズマ処理、コロナ処理、紫外線照射処理、フレーム(火炎)処理、ケン化処理のような表面活性化処理を行ってもよい。この表面活性化処理により、偏光フィルム10と第1,第2熱可塑性樹脂フィルム20、30との接着性を高めることができる。
As described above, the polarizing film 10 and the first and second thermoplastic resin films 20 and 30 can be bonded using an adhesive. Prior to laminating and bonding the first and second thermoplastic resin films 20 and 30 to the polarizing film 10, plasma is applied to the bonding surfaces of the polarizing film 10 and / or the first and second thermoplastic resin films 20 and 30. Surface activation treatment such as treatment, corona treatment, ultraviolet irradiation treatment, flame (flame) treatment, and saponification treatment may be performed. By this surface activation treatment, the adhesion between the polarizing film 10 and the first and second thermoplastic resin films 20 and 30 can be enhanced.
接着剤としては、水系接着剤、活性エネルギー線硬化性接着剤又は熱硬化性接着剤を用いることができ、好ましくは水系接着剤、活性エネルギー線硬化性接着剤である。偏光フィルム10の両面に熱可塑性樹脂フィルムを積層貼合する場合において両面の接着剤は、同種の接着剤あってもよいし異種の接着剤であってもよい。異種の接着剤を用いる場合には偏光板2はその枚葉体においてカールを生じやすくなるが、本発明によれば、異種の接着剤を用いることによって偏光板2が枚葉体としたときに逆カールを生じるものであっても、この逆カールを正カール方向へ効果的に矯正することができる。
As the adhesive, a water-based adhesive, an active energy ray-curable adhesive, or a thermosetting adhesive can be used, and a water-based adhesive and an active energy ray-curable adhesive are preferable. When a thermoplastic resin film is laminated and bonded to both surfaces of the polarizing film 10, the adhesive on both surfaces may be the same type of adhesive or different types of adhesive. When different types of adhesives are used, the polarizing plate 2 is likely to curl in the sheet, but according to the present invention, when the polarizing plate 2 is made into a sheet by using different types of adhesive. Even if the reverse curl is generated, the reverse curl can be effectively corrected in the normal curl direction.
水系接着剤は、接着剤成分を水に溶解したもの又は水に分散させたものである。好ましく用いられる水系接着剤は、例えば、主成分としてポリビニルアルコール系樹脂又はウレタン樹脂を用いた接着剤組成物である。
A water-based adhesive is one in which an adhesive component is dissolved in water or dispersed in water. The aqueous adhesive preferably used is, for example, an adhesive composition using a polyvinyl alcohol resin or a urethane resin as a main component.
接着剤の主成分としてポリビニルアルコール系樹脂を用いる場合、当該ポリビニルアルコール系樹脂は、部分ケン化ポリビニルアルコール、完全ケン化ポリビニルアルコールのようなポリビニルアルコール樹脂であることができるほか、カルボキシル基変性ポリビニルアルコール、アセトアセチル基変性ポリビニルアルコール、メチロール基変性ポリビニルアルコール、アミノ基変性ポリビニルアルコールのような変性されたポリビニルアルコール系樹脂であってもよい。ポリビニルアルコール系樹脂は、酢酸ビニルの単独重合体であるポリ酢酸ビニルをケン化処理して得られるビニルアルコールホモポリマーのほか、酢酸ビニルとこれに共重合可能な他の単量体との共重合体をケン化処理して得られるポリビニルアルコール系共重合体であってもよい。
When a polyvinyl alcohol-based resin is used as the main component of the adhesive, the polyvinyl alcohol-based resin can be a polyvinyl alcohol resin such as partially saponified polyvinyl alcohol or fully saponified polyvinyl alcohol, or a carboxyl group-modified polyvinyl alcohol. Further, modified polyvinyl alcohol resins such as acetoacetyl group-modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, and amino group-modified polyvinyl alcohol may be used. Polyvinyl alcohol resins include vinyl alcohol homopolymers obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate, as well as copolymerization of vinyl acetate and other monomers copolymerizable therewith. It may be a polyvinyl alcohol copolymer obtained by saponifying the coalescence.
ポリビニルアルコール系樹脂を接着剤成分とする水系接着剤は通常、ポリビニルアルコール系樹脂の水溶液である。接着剤中のポリビニルアルコール系樹脂の濃度は、水100重量部に対して、通常1~10重量部、好ましくは1~5重量部である。
An aqueous adhesive containing a polyvinyl alcohol resin as an adhesive component is usually an aqueous solution of a polyvinyl alcohol resin. The concentration of the polyvinyl alcohol resin in the adhesive is usually 1 to 10 parts by weight, preferably 1 to 5 parts by weight with respect to 100 parts by weight of water.
ポリビニルアルコール系樹脂の水溶液からなる接着剤は、接着性を向上させるために、多価アルデヒド、メラミン系化合物、ジルコニア化合物、亜鉛化合物、グリオキザール、グリオキザール誘導体、水溶性エポキシ樹脂のような硬化性成分や架橋剤を含有することが好ましい。水溶性エポキシ樹脂としては、例えばジエチレントリアミン、トリエチレンテトラミン等のポリアルキレンポリアミンと、アジピン酸等のジカルボン酸との反応で得られるポリアミドアミンに、エピクロロヒドリンを反応させて得られるポリアミドポリアミンエポキシ樹脂を好適に用いることができる。かかるポリアミドポリアミンエポキシ樹脂の市販品としては、「スミレーズレジン650」(田岡化学工業(株)製)、「スミレーズレジン675」(田岡化学工業(株)製)、「WS-525」(日本PMC(株)製)等が挙げられる。これら硬化性成分や架橋剤の添加量(硬化性成分及び架橋剤としてともに添加する場合にはその合計量)は、ポリビニルアルコール系樹脂100重量部に対して、通常1~100重量部、好ましくは1~50重量部である。上記硬化性成分や架橋剤の添加量がポリビニルアルコール系樹脂100重量部に対して1重量部未満である場合には、接着性向上の効果が小さくなる傾向にあり、また、当該添加量がポリビニルアルコール系樹脂100重量部に対して100重量部を超える場合には、接着剤層が脆くなる傾向にある。
Adhesives composed of aqueous solutions of polyvinyl alcohol resins are used to improve adhesiveness, such as curable components such as polyhydric aldehydes, melamine compounds, zirconia compounds, zinc compounds, glyoxal, glyoxal derivatives, and water-soluble epoxy resins. It is preferable to contain a crosslinking agent. Examples of water-soluble epoxy resins include polyamide polyamine epoxy resins obtained by reacting polychloroalkylenes such as diethylenetriamine and triethylenetetramine with polycarboxylic acid polyamines such as adipic acid and epichlorohydrin. Can be suitably used. Commercially available products of such polyamide polyamine epoxy resins include “Smiles Resin 650” (manufactured by Taoka Chemical Industry Co., Ltd.), “Smiles Resin 675” (manufactured by Taoka Chemical Industry Co., Ltd.), and “WS-525” (Japan). PMC Co., Ltd.). The addition amount of these curable components and crosslinking agents (the total amount when added as both the curable component and the crosslinking agent) is usually 1 to 100 parts by weight, preferably 100 parts by weight with respect to 100 parts by weight of the polyvinyl alcohol resin. 1 to 50 parts by weight. When the addition amount of the curable component or the crosslinking agent is less than 1 part by weight with respect to 100 parts by weight of the polyvinyl alcohol resin, the effect of improving the adhesiveness tends to be small, and the addition amount is polyvinyl. When it exceeds 100 parts by weight with respect to 100 parts by weight of the alcohol-based resin, the adhesive layer tends to become brittle.
また、接着剤の主成分としてウレタン樹脂を用いる場合の好適な例として、ポリエステル系アイオノマー型ウレタン樹脂とグリシジルオキシ基を有する化合物との混合物を挙げることができる。ポリエステル系アイオノマー型ウレタン樹脂とは、ポリエステル骨格を有するウレタン樹脂であって、その中に少量のイオン性成分(親水成分)が導入されたものである。かかるアイオノマー型ウレタン樹脂は、乳化剤を使用せずに直接、水中で乳化してエマルジョンとなるため、水系の接着剤として好適である。
In addition, as a suitable example when a urethane resin is used as the main component of the adhesive, a mixture of a polyester ionomer type urethane resin and a compound having a glycidyloxy group can be given. The polyester ionomer type urethane resin is a urethane resin having a polyester skeleton, into which a small amount of an ionic component (hydrophilic component) is introduced. Such an ionomer-type urethane resin is suitable as a water-based adhesive because it is emulsified directly in water without using an emulsifier to form an emulsion.
水系接着剤を使用する場合は、偏光フィルム10と第1及び/又は第2熱可塑性樹脂フィルム20,30とを貼合した後、水系接着剤中に含まれる水を除去するための乾燥工程を実施することが好ましい。乾燥工程後、例えば20~45℃の温度で養生する養生工程を設けてもよい。
In the case of using an aqueous adhesive, after the polarizing film 10 and the first and / or second thermoplastic resin films 20 and 30 are bonded, a drying step for removing water contained in the aqueous adhesive is performed. It is preferable to implement. After the drying process, for example, a curing process for curing at a temperature of 20 to 45 ° C. may be provided.
活性エネルギー線硬化性接着剤は、紫外線、可視光、電子線、X線のような活性エネルギー線の照射によって硬化する接着剤である。活性エネルギー線硬化性接着剤を用いる場合、偏光板2が有する接着剤層は、当該接着剤の硬化物層である。
The active energy ray-curable adhesive is an adhesive that is cured by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays. When an active energy ray-curable adhesive is used, the adhesive layer included in the polarizing plate 2 is a cured product layer of the adhesive.
活性エネルギー線硬化性接着剤は、カチオン重合によって硬化するエポキシ系化合物を硬化性成分として含有する接着剤であることができ、好ましくは、かかるエポキシ系化合物を硬化性成分として含有する紫外線硬化性接着剤である。ここでいうエポキシ系化合物とは、分子内に平均1個以上、好ましくは2個以上のエポキシ基を有する化合物を意味する。エポキシ系化合物は、1種のみを使用してもよいし2種以上を併用してもよい。
The active energy ray curable adhesive can be an adhesive containing an epoxy compound that is cured by cationic polymerization as a curable component, and preferably an ultraviolet curable adhesive containing such an epoxy compound as a curable component. It is an agent. The epoxy compound here means a compound having an average of 1 or more, preferably 2 or more epoxy groups in the molecule. The epoxy compound may be used alone or in combination of two or more.
好適に使用できるエポキシ系化合物の具体例は、芳香族ポリオールの芳香環に水素化反応を行って得られる脂環式ポリオールに、エピクロロヒドリンを反応させることにより得られる水素化エポキシ系化合物(脂環式環を有するポリオールのグリシジルエーテル);脂肪族多価アルコール又はそのアルキレンオキサイド付加物のポリグリシジルエーテルのような脂肪族エポキシ系化合物;脂環式環に結合したエポキシ基を分子内に1個以上有するエポキシ系化合物である脂環式エポキシ系化合物を含む。
Specific examples of the epoxy compound that can be suitably used include a hydrogenated epoxy compound obtained by reacting epichlorohydrin with an alicyclic polyol obtained by hydrogenating an aromatic ring of an aromatic polyol ( A glycidyl ether of a polyol having an alicyclic ring); an aliphatic epoxy compound such as an aliphatic polyhydric alcohol or a polyglycidyl ether of an alkylene oxide adduct thereof; an epoxy group bonded to the alicyclic ring in the molecule 1 An alicyclic epoxy compound, which is an epoxy compound having at least one, is included.
活性エネルギー線硬化性接着剤は、硬化性成分として、上記エポキシ系化合物の代わりに、又はこれとともにラジカル重合性である(メタ)アクリル系化合物を含有することができる。(メタ)アクリル系化合物としては、分子内に少なくとも1個の(メタ)アクリロイルオキシ基を有する(メタ)アクリレートモノマー;官能基含有化合物を2種以上反応させて得られ、分子内に少なくとも2個の(メタ)アクリロイルオキシ基を有する(メタ)アクリレートオリゴマー等の(メタ)アクリロイルオキシ基含有化合物を挙げることができる。
The active energy ray-curable adhesive can contain a radically polymerizable (meth) acrylic compound as a curable component, instead of or together with the epoxy compound. The (meth) acrylic compound is a (meth) acrylate monomer having at least one (meth) acryloyloxy group in the molecule; obtained by reacting two or more functional group-containing compounds, and at least two in the molecule. And (meth) acryloyloxy group-containing compounds such as (meth) acrylate oligomers having (meth) acryloyloxy groups.
活性エネルギー線硬化性接着剤は、カチオン重合によって硬化するエポキシ系化合物を硬化性成分として含む場合、光カチオン重合開始剤を含有することが好ましい。光カチオン重合開始剤としては、例えば、芳香族ジアゾニウム塩;芳香族ヨードニウム塩や芳香族スルホニウム塩等のオニウム塩;鉄-アレン錯体等を挙げることができる。また、活性エネルギー線硬化性接着剤が(メタ)アクリル系化合物のようなラジカル重合性硬化性成分を含有する場合は、光ラジカル重合開始剤を含有することが好ましい。光ラジカル重合開始剤としては、例えば、アセトフェノン系開始剤、ベンゾフェノン系開始剤、ベンゾインエーテル系開始剤、チオキサントン系開始剤、キサントン、フルオレノン、カンファーキノン、ベンズアルデヒド、アントラキノン等を挙げることができる。
When the active energy ray-curable adhesive contains an epoxy compound that is cured by cationic polymerization as a curable component, it preferably contains a photocationic polymerization initiator. Examples of the photocationic polymerization initiator include aromatic diazonium salts; onium salts such as aromatic iodonium salts and aromatic sulfonium salts; iron-allene complexes. Moreover, when the active energy ray-curable adhesive contains a radical polymerizable curable component such as a (meth) acrylic compound, it is preferable to contain a photo radical polymerization initiator. Examples of the photo radical polymerization initiator include acetophenone initiator, benzophenone initiator, benzoin ether initiator, thioxanthone initiator, xanthone, fluorenone, camphorquinone, benzaldehyde, anthraquinone and the like.
偏光フィルム10と第1及び/又は第2熱可塑性樹脂フィルム20,30との積層貼合に活性エネルギー線硬化性接着剤を用いる場合には、積層貼合後、必要に応じて乾燥工程を行い、次いで活性エネルギー線を照射することによって活性エネルギー線硬化性接着剤を硬化させる硬化工程を行う。活性エネルギー線の光源は特に限定されないが、波長400nm以下に発光分布を有する紫外線が好ましく、具体的には、低圧水銀灯、中圧水銀灯、高圧水銀灯、超高圧水銀灯、ケミカルランプ、ブラックライトランプ、マイクロウェーブ励起水銀灯、メタルハライドランプ等を用いることができる。
When an active energy ray-curable adhesive is used for laminating and laminating the polarizing film 10 and the first and / or second thermoplastic resin films 20 and 30, a drying process is performed as necessary after laminating and laminating. Then, a curing step of curing the active energy ray-curable adhesive by irradiating the active energy rays is performed. The light source of the active energy ray is not particularly limited, but ultraviolet light having a light emission distribution at a wavelength of 400 nm or less is preferable. Specifically, the low pressure mercury lamp, the medium pressure mercury lamp, the high pressure mercury lamp, the ultrahigh pressure mercury lamp, the chemical lamp, the black light lamp, the micro A wave excitation mercury lamp, a metal halide lamp, etc. can be used.
活性エネルギー線硬化性接着剤からなる接着剤層への活性エネルギー線照射強度は、接着剤の組成によって適宜決定されるが、重合開始剤の活性化に有効な波長領域の照射強度が0.1~6000mW/cm2となるように設定されることが好ましい。照射強度が0.1mW/cm2以上である場合、反応時間が長くなりすぎず、6000mW/cm2以下である場合、光源から輻射される熱及び接着剤の硬化時の発熱による接着剤層の黄変や偏光フィルム10の劣化を生じるおそれが少ない。
The active energy ray irradiation intensity to the adhesive layer composed of the active energy ray-curable adhesive is appropriately determined depending on the composition of the adhesive, but the irradiation intensity in the wavelength region effective for activating the polymerization initiator is 0.1. It is preferably set to be ˜6000 mW / cm 2 . When the irradiation intensity is 0.1 mW / cm 2 or more, the reaction time does not become too long, and when it is 6000 mW / cm 2 or less, the heat of the adhesive layer due to the heat radiated from the light source and the heat generated when the adhesive is cured. There is little possibility of causing yellowing or deterioration of the polarizing film 10.
活性エネルギー線の照射時間についても、接着剤の組成によって適宜決定されるが、上記照射強度と照射時間との積として表される積算光量が10~10000mJ/cm2となるように設定されることが好ましい。積算光量が10mJ/cm2以上である場合、重合開始剤由来の活性種を十分量発生させて硬化反応をより確実に進行させることができ、10000mJ/cm2以下である場合、照射時間が長くなりすぎず、偏光板2の良好な生産性を維持できる。
The irradiation time of the active energy ray is also appropriately determined depending on the composition of the adhesive, but is set so that the integrated light amount expressed as the product of the irradiation intensity and the irradiation time is 10 to 10,000 mJ / cm 2. Is preferred. When the integrated light amount is 10 mJ / cm 2 or more, a sufficient amount of active species derived from the polymerization initiator can be generated to advance the curing reaction more reliably, and when it is 10000 mJ / cm 2 or less, the irradiation time is long. The productivity of the polarizing plate 2 can be maintained without becoming too much.
(3-4)粘着剤層及びセパレートフィルム
図3及び図4に示されるように偏光板2は、粘着剤層40を含むことができる。この粘着剤層40は、第1若しくは第2熱可塑性樹脂フィルム20,30又は偏光フィルム10の表面に直接積層することができ、プロテクトフィルム付偏光板3を画像表示素子(例えば液晶セル)に貼合するために用いることができる。 (3-4) Adhesive Layer and Separate Film As shown in FIGS. 3 and 4, thepolarizing plate 2 can include an adhesive layer 40. The pressure-sensitive adhesive layer 40 can be directly laminated on the surface of the first or second thermoplastic resin film 20, 30 or the polarizing film 10, and the polarizing plate 3 with a protective film is attached to an image display element (for example, a liquid crystal cell). Can be used to match.
図3及び図4に示されるように偏光板2は、粘着剤層40を含むことができる。この粘着剤層40は、第1若しくは第2熱可塑性樹脂フィルム20,30又は偏光フィルム10の表面に直接積層することができ、プロテクトフィルム付偏光板3を画像表示素子(例えば液晶セル)に貼合するために用いることができる。 (3-4) Adhesive Layer and Separate Film As shown in FIGS. 3 and 4, the
プロテクトフィルム付偏光板3を画像表示素子(例えば液晶セル)に貼合するための粘着剤層40は、液晶セルなどの画像表示素子に貼合される側の偏光板の主面(第1主面)側に配置される。例えば偏光板2が第1及び第2熱可塑性樹脂フィルム20,30を含み、第1熱可塑性樹脂フィルム20として、第2熱可塑性樹脂フィルム30よりも平衡水分率及び/又は透湿度が高いフィルムを用いる場合、粘着剤層40は、第2熱可塑性樹脂フィルム30側に配置することができる。
The pressure-sensitive adhesive layer 40 for bonding the polarizing plate 3 with a protective film to an image display element (for example, a liquid crystal cell) is the main surface (first main surface) of the polarizing plate on the side bonded to the image display element such as a liquid crystal cell. Surface) side. For example, the polarizing plate 2 includes first and second thermoplastic resin films 20 and 30, and the first thermoplastic resin film 20 is a film having a higher equilibrium moisture content and / or moisture permeability than the second thermoplastic resin film 30. When used, the pressure-sensitive adhesive layer 40 can be disposed on the second thermoplastic resin film 30 side.
粘着剤層40は、(メタ)アクリル系、ゴム系、ウレタン系、エステル系、シリコーン系、ポリビニルエーテル系のような樹脂を主成分(ベースポリマー)とする粘着剤組成物で構成することができる。中でも、透明性、耐候性、耐熱性等に優れる(メタ)アクリル系樹脂をベースポリマーとする粘着剤組成物が好適である。粘着剤組成物は、活性エネルギー線硬化型、熱硬化型であってもよい。
The pressure-sensitive adhesive layer 40 can be composed of a pressure-sensitive adhesive composition containing a resin such as (meth) acrylic, rubber-based, urethane-based, ester-based, silicone-based, or polyvinylether-based as a main component (base polymer). . Especially, the adhesive composition which uses (meth) acrylic resin excellent in transparency, weather resistance, heat resistance, etc. as a base polymer is suitable. The pressure-sensitive adhesive composition may be an active energy ray curable type or a thermosetting type.
粘着剤組成物に用いられる(メタ)アクリル系樹脂としては、例えば、(メタ)アクリル酸ブチル、(メタ)アクリル酸エチル、(メタ)アクリル酸イソオクチル、(メタ)アクリル酸2-エチルヘキシルのような(メタ)アクリル酸エステルの1種又は2種以上をモノマーとする重合体又は共重合体が好適に用いられる。(メタ)アクリル系樹脂には、極性モノマーを共重合させることが好ましい。極性モノマーとしては、例えば、(メタ)アクリル酸、(メタ)アクリル酸2-ヒドロキシプロピル、(メタ)アクリル酸ヒドロキシエチル、(メタ)アクリルアミド、N,N-ジメチルアミノエチル(メタ)アクリレート、グリシジル(メタ)アクリレートのような、カルボキシル基、水酸基、アミド基、アミノ基、エポキシ基等を有するモノマーを挙げることができる。
Examples of the (meth) acrylic resin used in the pressure-sensitive adhesive composition include butyl (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. A polymer or copolymer having one or more (meth) acrylic acid esters as monomers is preferably used. The (meth) acrylic resin is preferably copolymerized with a polar monomer. Examples of polar monomers include (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, glycidyl ( Mention may be made of monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group and the like, such as (meth) acrylate.
粘着剤組成物は、上記ベースポリマーのみを含むものであってもよいが、通常は架橋剤をさらに含有する。架橋剤としては、2価以上の金属イオンであって、カルボキシル基との間でカルボン酸金属塩を形成するもの;ポリアミン化合物であって、カルボキシル基との間でアミド結合を形成するもの;ポリエポキシ化合物やポリオールであって、カルボキシル基との間でエステル結合を形成するもの;ポリイソシアネート化合物であって、カルボキシル基との間でアミド結合を形成するものが例示される。中でも、ポリイソシアネート化合物が好ましい。
The pressure-sensitive adhesive composition may contain only the above base polymer, but usually further contains a crosslinking agent. As a crosslinking agent, a metal ion having a valence of 2 or more, which forms a carboxylic acid metal salt with a carboxyl group; a polyamine compound, which forms an amide bond with a carboxyl group; Examples thereof include epoxy compounds and polyols that form ester bonds with carboxyl groups; polyisocyanate compounds that form amide bonds with carboxyl groups. Of these, polyisocyanate compounds are preferred.
活性エネルギー線硬化型粘着剤組成物とは、紫外線や電子線のような活性エネルギー線の照射を受けて硬化する性質を有しており、活性エネルギー線照射前においても粘着性を有してフィルム等の被着体に密着させることができ、活性エネルギー線の照射によって硬化して密着力の調整ができる性質を有する粘着剤組成物である。活性エネルギー線硬化型粘着剤組成物は、紫外線硬化型であることが好ましい。活性エネルギー線硬化型粘着剤組成物は、ベースポリマー、架橋剤に加えて、活性エネルギー線重合性化合物をさらに含有する。さらに必要に応じて、光重合開始剤や光増感剤等を含有させることもある。
The active energy ray-curable pressure-sensitive adhesive composition has a property of being cured by irradiation with active energy rays such as ultraviolet rays and electron beams, and has an adhesive property even before irradiation with active energy rays. It is a pressure-sensitive adhesive composition having such a property that it can be adhered to an adherend such as the like and can be cured by irradiation with active energy rays to adjust the adhesion. The active energy ray-curable pressure-sensitive adhesive composition is preferably ultraviolet curable. The active energy ray-curable pressure-sensitive adhesive composition further contains an active energy ray-polymerizable compound in addition to the base polymer and the crosslinking agent. Further, if necessary, a photopolymerization initiator, a photosensitizer and the like may be contained.
粘着剤組成物は、光散乱性を付与するための微粒子、ビーズ(樹脂ビーズ、ガラスビーズ等)、ガラス繊維、ベースポリマー以外の樹脂、粘着性付与剤、充填剤(金属粉やその他の無機粉末等)、酸化防止剤、紫外線吸収剤、染料、顔料、着色剤、消泡剤、腐食防止剤、光重合開始剤等の添加剤を含むことができる。
Adhesive composition consists of fine particles for imparting light scattering properties, beads (resin beads, glass beads, etc.), glass fibers, resins other than base polymers, tackifiers, fillers (metal powder and other inorganic powders) Etc.), antioxidants, ultraviolet absorbers, dyes, pigments, colorants, antifoaming agents, corrosion inhibitors, photopolymerization initiators and the like.
粘着剤層40は、上記粘着剤組成物の有機溶剤希釈液を偏光板2の粘着剤層形成面(すなわち、偏光フィルム10、又は第1若しくは第2熱可塑性樹脂フィルム20,30)上に塗布し、乾燥させることにより形成することができる。あるいは、上記粘着剤組成物の有機溶剤希釈液をセパレートフィルム(例えばセパレートフィルム50)上に塗布し、乾燥させて粘着剤層を形成した後、これを偏光板2の粘着剤層形成面に転写してもよい。いずれの方法においても、粘着剤層40の外面にセパレートフィルムを貼着し、使用時まで粘着剤層40を保護しておくことが好ましい。活性エネルギー線硬化型粘着剤組成物を用いた場合は、形成された粘着剤層に、活性エネルギー線を照射することにより所望の硬化度を有する硬化物とすることができる。粘着剤層40の厚みは、通常1~40μmであるが、偏光板2の薄膜化の観点から、3~25μmとすることが好ましい。
The pressure-sensitive adhesive layer 40 is obtained by applying an organic solvent dilution of the above-mentioned pressure-sensitive adhesive composition onto the pressure-sensitive adhesive layer-forming surface of the polarizing plate 2 (that is, the polarizing film 10 or the first or second thermoplastic resin film 20, 30). And can be formed by drying. Or after apply | coating the organic solvent dilution liquid of the said adhesive composition on a separate film (for example, separate film 50) and making it dry and forming an adhesive layer, this is transcribe | transferred to the adhesive layer formation surface of the polarizing plate 2 May be. In any method, it is preferable to attach a separate film to the outer surface of the pressure-sensitive adhesive layer 40 and protect the pressure-sensitive adhesive layer 40 until use. When the active energy ray-curable pressure-sensitive adhesive composition is used, a cured product having a desired degree of curing can be obtained by irradiating the formed pressure-sensitive adhesive layer with active energy rays. The thickness of the pressure-sensitive adhesive layer 40 is usually 1 to 40 μm, but is preferably 3 to 25 μm from the viewpoint of thinning the polarizing plate 2.
セパレートフィルム50は、粘着剤層40を画像表示素子(例えば液晶セル)に貼合するまでその表面を保護するために貼着されるフィルムである。セパレートフィルム50は通常、片面に離型処理が施された熱可塑性樹脂フィルムで構成され、その離型処理面が粘着剤層40に貼り合わされる。セパレートフィルム50を構成する熱可塑性樹脂は、例えば、ポリエチレンのようなポリエチレン系樹脂、ポリプロピレンのようなポリプロピレン系樹脂、ポリエチレンテレフタレートやポリエチレンナフタレートのようなポリエステル系樹脂等であることができる。セパレートフィルム50の厚みは、例えば10~100μmである。
The separate film 50 is a film that is attached to protect the surface of the adhesive layer 40 until it is attached to an image display element (for example, a liquid crystal cell). The separate film 50 is usually composed of a thermoplastic resin film that has been subjected to a release treatment on one side, and the release treatment surface is bonded to the adhesive layer 40. The thermoplastic resin constituting the separate film 50 can be, for example, a polyethylene resin such as polyethylene, a polypropylene resin such as polypropylene, a polyester resin such as polyethylene terephthalate or polyethylene naphthalate, and the like. The thickness of the separate film 50 is, for example, 10 to 100 μm.
(3-5)偏光板のその他の構成要素
偏光板2は、上記以外の他の構成要素を含むことができる。他の構成要素としては、偏光フィルム10以外の他の光学機能を有する光学層又は光学フィルムを挙げることができ、その具体例は位相差フィルム、輝度向上フィルムなどの光学フィルムである。他の光学フィルムは、粘着剤層や接着剤層を介して積層貼合することができる。 (3-5) Other Components of Polarizing Plate Thepolarizing plate 2 can contain other components other than those described above. Examples of other components include an optical layer or an optical film having an optical function other than the polarizing film 10, and specific examples thereof are optical films such as a retardation film and a brightness enhancement film. Other optical films can be laminated and bonded via a pressure-sensitive adhesive layer or an adhesive layer.
偏光板2は、上記以外の他の構成要素を含むことができる。他の構成要素としては、偏光フィルム10以外の他の光学機能を有する光学層又は光学フィルムを挙げることができ、その具体例は位相差フィルム、輝度向上フィルムなどの光学フィルムである。他の光学フィルムは、粘着剤層や接着剤層を介して積層貼合することができる。 (3-5) Other Components of Polarizing Plate The
また偏光板2は、上記押圧する工程に供されるプロテクトフィルム1とは異なるプロテクトフィルムを含むことができる。このプロテクトフィルムは、偏光板2の一方の表面に配置される。このプロテクトフィルムの構成については、前述したプロテクトフィルム1についての記述が引用される。
Further, the polarizing plate 2 can include a protective film different from the protective film 1 subjected to the pressing step. This protect film is disposed on one surface of the polarizing plate 2. As for the structure of this protect film, the above description of the protect film 1 is cited.
(3-6)偏光板のカール
上述のように本発明によれば、偏光板2を正カール方向に矯正することができ、これにより、枚葉体としたときに逆カールが十分に抑制されている、好ましくはカールを有さずフラットであるか、又は正カールを有するプロテクトフィルム付偏光板3を得ることができる。本発明に係る製造方法は、偏光板2が枚葉体としたときに逆カール(プロテクトフィルム1が重ねられる主面側を凸とするカール)を生じるものである場合(さらには、逆カールであって、かつMDカールを生じるものである場合)にとりわけ有利である。 (3-6) Curling of Polarizing Plate As described above, according to the present invention, it is possible to correct thepolarizing plate 2 in the normal curl direction. The polarizing plate 3 with a protective film can be obtained which is preferably flat without curling or having positive curl. In the manufacturing method according to the present invention, when the polarizing plate 2 is a sheet, a reverse curl (a curl having a convex main surface on which the protective film 1 is superimposed) is generated (further, it is a reverse curl). And is particularly advantageous for MD curl).
上述のように本発明によれば、偏光板2を正カール方向に矯正することができ、これにより、枚葉体としたときに逆カールが十分に抑制されている、好ましくはカールを有さずフラットであるか、又は正カールを有するプロテクトフィルム付偏光板3を得ることができる。本発明に係る製造方法は、偏光板2が枚葉体としたときに逆カール(プロテクトフィルム1が重ねられる主面側を凸とするカール)を生じるものである場合(さらには、逆カールであって、かつMDカールを生じるものである場合)にとりわけ有利である。 (3-6) Curling of Polarizing Plate As described above, according to the present invention, it is possible to correct the
上では、枚葉体としたときに逆カールが生じやすい偏光板2の形態の1つとして、第1熱可塑性樹脂フィルム20と第2熱可塑性樹脂フィルム30とが互いに異なる平衡水分率及び/又は透湿度を有する場合を挙げたが、これに限定されず、逆カールは、偏光板2が偏光フィルム10を基準に非対称の層構成を有する場合などにおいて生じやすい。
In the above, as one of the forms of the polarizing plate 2 in which reverse curling is likely to occur when the sheet is formed, the first thermoplastic resin film 20 and the second thermoplastic resin film 30 have different equilibrium moisture contents and / or different from each other. Although the case where it has moisture permeability was mentioned, it is not limited to this, and reverse curl tends to occur, for example, when the polarizing plate 2 has an asymmetric layer structure with respect to the polarizing film 10.
逆カールを生じやすい偏光板2の構成の例は次のとおりである。
(a)偏光フィルム10の片面にのみ熱可塑性樹脂フィルム(保護フィルム等)が貼合されている構成、
(b)偏光フィルム10の一方の面に保護フィルムが貼合されており、他方の面に保護フィルム以外の光学フィルム(輝度向上フィルム等)が貼合されている構成、
(c)偏光フィルム10の両面に貼合される熱可塑性樹脂フィルム(保護フィルム等)の構成(樹脂種、厚み、平衡水分率、透湿度、表面処理層の有無等)が互いに異なる構成、(d)偏光フィルム10の両面に熱可塑性樹脂フィルム(保護フィルム等)を貼合するための接着剤層が互いに異種の接着剤から形成される構成、
(e)偏光フィルム10の両面に熱可塑性樹脂フィルム(保護フィルム等)が貼合されており、かつ一方の熱可塑性樹脂フィルム上に他の光学フィルムが貼合されている構成、
(f)その他、偏光フィルム10を基準に、一方側におけるフィルム及び層の合計数と、他方側におけるフィルム及び層の合計数とが異なる構成。 An example of the configuration of thepolarizing plate 2 that easily causes reverse curling is as follows.
(A) A configuration in which a thermoplastic resin film (such as a protective film) is bonded only to one side of thepolarizing film 10,
(B) A configuration in which a protective film is bonded to one surface of thepolarizing film 10, and an optical film (such as a brightness enhancement film) other than the protective film is bonded to the other surface,
(C) Configurations of the thermoplastic resin films (protective films, etc.) bonded to both surfaces of the polarizing film 10 (resin type, thickness, equilibrium moisture content, moisture permeability, presence / absence of surface treatment layer, etc.) are different from each other. d) a configuration in which adhesive layers for bonding a thermoplastic resin film (such as a protective film) on both surfaces of thepolarizing film 10 are formed from different types of adhesives;
(E) A configuration in which a thermoplastic resin film (protective film or the like) is bonded to both surfaces of thepolarizing film 10 and another optical film is bonded to one thermoplastic resin film,
(F) Other than thepolarizing film 10, the total number of films and layers on one side is different from the total number of films and layers on the other side.
(a)偏光フィルム10の片面にのみ熱可塑性樹脂フィルム(保護フィルム等)が貼合されている構成、
(b)偏光フィルム10の一方の面に保護フィルムが貼合されており、他方の面に保護フィルム以外の光学フィルム(輝度向上フィルム等)が貼合されている構成、
(c)偏光フィルム10の両面に貼合される熱可塑性樹脂フィルム(保護フィルム等)の構成(樹脂種、厚み、平衡水分率、透湿度、表面処理層の有無等)が互いに異なる構成、(d)偏光フィルム10の両面に熱可塑性樹脂フィルム(保護フィルム等)を貼合するための接着剤層が互いに異種の接着剤から形成される構成、
(e)偏光フィルム10の両面に熱可塑性樹脂フィルム(保護フィルム等)が貼合されており、かつ一方の熱可塑性樹脂フィルム上に他の光学フィルムが貼合されている構成、
(f)その他、偏光フィルム10を基準に、一方側におけるフィルム及び層の合計数と、他方側におけるフィルム及び層の合計数とが異なる構成。 An example of the configuration of the
(A) A configuration in which a thermoplastic resin film (such as a protective film) is bonded only to one side of the
(B) A configuration in which a protective film is bonded to one surface of the
(C) Configurations of the thermoplastic resin films (protective films, etc.) bonded to both surfaces of the polarizing film 10 (resin type, thickness, equilibrium moisture content, moisture permeability, presence / absence of surface treatment layer, etc.) are different from each other. d) a configuration in which adhesive layers for bonding a thermoplastic resin film (such as a protective film) on both surfaces of the
(E) A configuration in which a thermoplastic resin film (protective film or the like) is bonded to both surfaces of the
(F) Other than the
(4)その他の工程
本発明に係る製造方法は、上記押圧する工程によって得られるプロテクトフィルム付偏光板3を裁断して、プロテクトフィルム付偏光板3の枚葉体を得る工程をさらに含むことができる。裁断には、シアーカッターなど通常用いられる裁断装置を用いることができる。 (4) Other steps The production method according to the present invention may further include a step of cutting thepolarizing plate 3 with the protective film obtained by the pressing step to obtain a sheet of the polarizing plate 3 with the protective film. it can. For cutting, a commonly used cutting device such as a shear cutter can be used.
本発明に係る製造方法は、上記押圧する工程によって得られるプロテクトフィルム付偏光板3を裁断して、プロテクトフィルム付偏光板3の枚葉体を得る工程をさらに含むことができる。裁断には、シアーカッターなど通常用いられる裁断装置を用いることができる。 (4) Other steps The production method according to the present invention may further include a step of cutting the
枚葉体の形状は特に制限されないが、通常は方形形状であり、長辺と短辺とを有する方形形状であることが好ましく、長方形であることがより好ましい。この枚葉体は、通常、対向する一対の辺がMDと平行であり、残りの対向する一対の辺がTDと平行となるように裁断されるが、各辺がMD又はTDから傾いた方向となるように裁断されてもよい。枚葉体の長辺及び短辺の長さは特に制限されないが、通常、長辺は50mm以上であり、短辺は30mm以上である。カールは、枚葉体のサイズが大きいほど生じやすい。サイズ(長辺及び/又は短辺)があまりに小さい場合には、カールの問題それ自体が生じにくい。
The shape of the single wafer is not particularly limited, but is usually a rectangular shape, preferably a rectangular shape having a long side and a short side, and more preferably a rectangular shape. This sheet is usually cut so that a pair of opposing sides are parallel to MD and the remaining pair of opposing sides are parallel to TD, but each side is inclined from MD or TD. You may cut | judge so that it may become. Although the length of the long side and the short side of the single wafer is not particularly limited, the long side is usually 50 mm or more and the short side is 30 mm or more. The curl is more likely to occur as the size of the sheet body increases. If the size (long side and / or short side) is too small, the curl problem itself is less likely to occur.
以下、実施例及び比較例を示して本発明をさらに具体的に説明するが、本発明はこれらの例によって限定されるものではない。なお、以下の例において平衡水分率、透湿度、厚み、貼合ロールの硬度及びカール量は、以下の方法に従って測定した。
Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples. In the following examples, the equilibrium moisture content, moisture permeability, thickness, bonding roll hardness and curl amount were measured according to the following methods.
(1)フィルムの平衡水分率
MD長さ150mm×TD長さ100mmの試験片を切り出した。温度23℃、相対湿度55%の環境下に24時間保管した後のフィルム重量を測定した。その後、105℃で2時間乾燥処理を行い、乾燥処理後のフィルム重量を測定した。乾燥前後のフィルム重量より、下記式:
平衡水分率(重量%)={(乾燥処理前のフィルム重量-乾燥処理後のフィルム重量)/乾燥処理前のフィルム重量}×100
に基づき平衡水分率を求めた。 (1) Equilibrium moisture content of film A test piece having an MD length of 150 mm and a TD length of 100 mm was cut out. The film weight after storage for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 55% was measured. Then, the drying process was performed at 105 degreeC for 2 hours, and the film weight after a drying process was measured. From the film weight before and after drying, the following formula:
Equilibrium moisture content (% by weight) = {(film weight before drying treatment−film weight after drying treatment) / film weight before drying treatment} × 100
Based on this, the equilibrium moisture content was determined.
MD長さ150mm×TD長さ100mmの試験片を切り出した。温度23℃、相対湿度55%の環境下に24時間保管した後のフィルム重量を測定した。その後、105℃で2時間乾燥処理を行い、乾燥処理後のフィルム重量を測定した。乾燥前後のフィルム重量より、下記式:
平衡水分率(重量%)={(乾燥処理前のフィルム重量-乾燥処理後のフィルム重量)/乾燥処理前のフィルム重量}×100
に基づき平衡水分率を求めた。 (1) Equilibrium moisture content of film A test piece having an MD length of 150 mm and a TD length of 100 mm was cut out. The film weight after storage for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 55% was measured. Then, the drying process was performed at 105 degreeC for 2 hours, and the film weight after a drying process was measured. From the film weight before and after drying, the following formula:
Equilibrium moisture content (% by weight) = {(film weight before drying treatment−film weight after drying treatment) / film weight before drying treatment} × 100
Based on this, the equilibrium moisture content was determined.
(2)フィルムの透湿度
JIS Z 0208に規定されるカップ法により、温度40℃、相対湿度90%での透湿度〔g/(m2・24hr)〕を測定した。 (2) Moisture permeability of film Moisture permeability [g / (m 2 · 24 hr)] at a temperature of 40 ° C. and a relative humidity of 90% was measured by a cup method defined in JIS Z 0208.
JIS Z 0208に規定されるカップ法により、温度40℃、相対湿度90%での透湿度〔g/(m2・24hr)〕を測定した。 (2) Moisture permeability of film Moisture permeability [g / (m 2 · 24 hr)] at a temperature of 40 ° C. and a relative humidity of 90% was measured by a cup method defined in JIS Z 0208.
(3)偏光板及びフィルムの厚み
(株)ニコン製のデジタルマイクロメーター「MH-15M」を用いて測定した。 (3) Thickness of polarizing plate and film The thickness was measured using a digital micrometer “MH-15M” manufactured by Nikon Corporation.
(株)ニコン製のデジタルマイクロメーター「MH-15M」を用いて測定した。 (3) Thickness of polarizing plate and film The thickness was measured using a digital micrometer “MH-15M” manufactured by Nikon Corporation.
(4)貼合ロールの硬度
JIS K 6253に規定されるタイプAデュロメータ硬さ試験機(アスカ社製のゴム硬度計「Type-A」)を用いて、温度23℃、相対湿度50%での硬度〔°〕を測定した。 (4) Hardness of laminating roll Using a type A durometer hardness tester (Asuka rubber hardness tester “Type-A”) defined in JIS K 6253 at a temperature of 23 ° C. and a relative humidity of 50%. Hardness [°] was measured.
JIS K 6253に規定されるタイプAデュロメータ硬さ試験機(アスカ社製のゴム硬度計「Type-A」)を用いて、温度23℃、相対湿度50%での硬度〔°〕を測定した。 (4) Hardness of laminating roll Using a type A durometer hardness tester (Asuka rubber hardness tester “Type-A”) defined in JIS K 6253 at a temperature of 23 ° C. and a relative humidity of 50%. Hardness [°] was measured.
(5)プロテクトフィルム付偏光板及び偏光板のカール量
得られたプロテクトフィルム付偏光板から、MD長さ300mm×TD長さ200mmの長方形の試験片を切り出し、温度25℃、相対湿度55%の環境下で24時間放置した。この試験片をその凹面を上にして、すなわち4つの端辺が持ち上がった状態になるように基準面(水平な台)上に置いた。この状態で試験片の4つの角のそれぞれについて基準面からの高さを測定し、それら4つの角の高さの平均としてカール量〔mm〕を求めた。カール量が正の値である場合は、第1熱可塑性樹脂フィルム側が凹となっていることを意味し(正カール)、負の値である場合は、第2熱可塑性樹脂フィルム側が凹となっていることを意味する(逆カール)。 (5) Polarizing plate with protective film and curl amount of polarizing plate From the obtained polarizing plate with protective film, a rectangular test piece having an MD length of 300 mm × TD length of 200 mm was cut out at a temperature of 25 ° C. and a relative humidity of 55%. It was left in the environment for 24 hours. The test piece was placed on the reference surface (horizontal platform) with its concave surface up, that is, with the four edges raised. In this state, the height from the reference surface was measured for each of the four corners of the test piece, and the curl amount [mm] was obtained as an average of the heights of the four corners. When the curl amount is a positive value, it means that the first thermoplastic resin film side is concave (positive curl), and when it is a negative value, the second thermoplastic resin film side is concave. (Reverse curl).
得られたプロテクトフィルム付偏光板から、MD長さ300mm×TD長さ200mmの長方形の試験片を切り出し、温度25℃、相対湿度55%の環境下で24時間放置した。この試験片をその凹面を上にして、すなわち4つの端辺が持ち上がった状態になるように基準面(水平な台)上に置いた。この状態で試験片の4つの角のそれぞれについて基準面からの高さを測定し、それら4つの角の高さの平均としてカール量〔mm〕を求めた。カール量が正の値である場合は、第1熱可塑性樹脂フィルム側が凹となっていることを意味し(正カール)、負の値である場合は、第2熱可塑性樹脂フィルム側が凹となっていることを意味する(逆カール)。 (5) Polarizing plate with protective film and curl amount of polarizing plate From the obtained polarizing plate with protective film, a rectangular test piece having an MD length of 300 mm × TD length of 200 mm was cut out at a temperature of 25 ° C. and a relative humidity of 55%. It was left in the environment for 24 hours. The test piece was placed on the reference surface (horizontal platform) with its concave surface up, that is, with the four edges raised. In this state, the height from the reference surface was measured for each of the four corners of the test piece, and the curl amount [mm] was obtained as an average of the heights of the four corners. When the curl amount is a positive value, it means that the first thermoplastic resin film side is concave (positive curl), and when it is a negative value, the second thermoplastic resin film side is concave. (Reverse curl).
<実施例1>
(A)偏光フィルムの作製
長尺のポリビニルアルコールフィルム(平均重合度:約2400、ケン化度:99.9モル%以上、厚み:30μm)を連続的に搬送しながら、乾式で約4倍に一軸延伸し、さらに緊張状態を保ったまま、40℃の純水に1分間浸漬した後、ヨウ素/ヨウ化カリウム/水の重量比が0.1/5/100の水溶液に28℃で60秒間浸漬した。その後、ヨウ化カリウム/ホウ酸/水の重量比が10.5/7.5/100の水溶液に68℃で300秒間浸漬した。引き続き、5℃の純水で5秒間洗浄した後、70℃で180秒間乾燥して、一軸延伸されたポリビニルアルコールフィルムにヨウ素が吸着配向された長尺の偏光フィルムを得た。偏光フィルムの厚みは11.1μmであった。 <Example 1>
(A) Production of Polarizing Film While continuously transporting a long polyvinyl alcohol film (average polymerization degree: about 2400, saponification degree: 99.9 mol% or more, thickness: 30 μm), it is about 4 times dry. The film was uniaxially stretched and immersed in pure water at 40 ° C. for 1 minute while maintaining the tension state, and then in an aqueous solution having a weight ratio of iodine / potassium iodide / water of 0.1 / 5/100 at 28 ° C. for 60 seconds. Soaked. Thereafter, it was immersed in an aqueous solution having a weight ratio of potassium iodide / boric acid / water of 10.5 / 7.5 / 100 at 68 ° C. for 300 seconds. Subsequently, it was washed with pure water at 5 ° C. for 5 seconds and then dried at 70 ° C. for 180 seconds to obtain a long polarizing film in which iodine was adsorbed and oriented on a uniaxially stretched polyvinyl alcohol film. The thickness of the polarizing film was 11.1 μm.
(A)偏光フィルムの作製
長尺のポリビニルアルコールフィルム(平均重合度:約2400、ケン化度:99.9モル%以上、厚み:30μm)を連続的に搬送しながら、乾式で約4倍に一軸延伸し、さらに緊張状態を保ったまま、40℃の純水に1分間浸漬した後、ヨウ素/ヨウ化カリウム/水の重量比が0.1/5/100の水溶液に28℃で60秒間浸漬した。その後、ヨウ化カリウム/ホウ酸/水の重量比が10.5/7.5/100の水溶液に68℃で300秒間浸漬した。引き続き、5℃の純水で5秒間洗浄した後、70℃で180秒間乾燥して、一軸延伸されたポリビニルアルコールフィルムにヨウ素が吸着配向された長尺の偏光フィルムを得た。偏光フィルムの厚みは11.1μmであった。 <Example 1>
(A) Production of Polarizing Film While continuously transporting a long polyvinyl alcohol film (average polymerization degree: about 2400, saponification degree: 99.9 mol% or more, thickness: 30 μm), it is about 4 times dry. The film was uniaxially stretched and immersed in pure water at 40 ° C. for 1 minute while maintaining the tension state, and then in an aqueous solution having a weight ratio of iodine / potassium iodide / water of 0.1 / 5/100 at 28 ° C. for 60 seconds. Soaked. Thereafter, it was immersed in an aqueous solution having a weight ratio of potassium iodide / boric acid / water of 10.5 / 7.5 / 100 at 68 ° C. for 300 seconds. Subsequently, it was washed with pure water at 5 ° C. for 5 seconds and then dried at 70 ° C. for 180 seconds to obtain a long polarizing film in which iodine was adsorbed and oriented on a uniaxially stretched polyvinyl alcohol film. The thickness of the polarizing film was 11.1 μm.
(B)偏光板の作製
上記(A)で得られた偏光フィルムを連続的に搬送するとともに、長尺の第1熱可塑性樹脂フィルム〔コニカミノルタオプト(株)製のTACフィルム「KC2UAW」にハードコート層が形成されたフィルム、厚み:32.4μm、平衡水分率:1.9重量%、透湿度:455g/(m2・24hr)〕及び長尺の第2熱可塑性樹脂フィルム〔JSR(株)製の環状ポリオレフィン系樹脂フィルムである商品名「FEKB015D3」、厚み:15.1μm、平衡水分率:0.8重量%、透湿度:115g/(m2・24hr)〕を連続的に搬送し、偏光フィルムと第1熱可塑性樹脂フィルムとの間、及び偏光フィルムと第2熱可塑性樹脂フィルムとの間に水系接着剤を注入しながら、貼合ロール間に通して第1熱可塑性樹脂フィルム/水系接着剤層/偏光フィルム/水系接着剤層/第2熱可塑性樹脂フィルムからなる積層フィルムを得た。引き続き、得られた積層フィルムを搬送し、熱風乾燥機に通して80℃、300秒の加熱処理を行うことにより水系接着剤層を乾燥させて、偏光板を得た。上記の水系接着剤には、ポリビニルアルコール粉末〔日本合成化学工業(株)製の商品名「ゴーセファイマー」、平均重合度1100〕を95℃の熱水に溶解して得られた濃度3重量%のポリビニルアルコール水溶液に架橋剤〔日本合成化学工業(株)製のグリオキシル酸ナトリウム〕をポリビニルアルコール粉末10重量部に対して1重量部の割合で混合した水溶液を用いた。 (B) Preparation of polarizing plate While continuously transporting the polarizing film obtained in (A) above, the first thermoplastic resin film [Konica Minolta Opto Co., Ltd. TAC film “KC2UAW” Film with a coating layer, thickness: 32.4 μm, equilibrium moisture content: 1.9 wt%, moisture permeability: 455 g / (m 2 · 24 hr)] and a long second thermoplastic resin film [JSR Corporation ) Product name “FEKB015D3”, which is a cyclic polyolefin resin film manufactured in the following manner: thickness: 15.1 μm, equilibrium moisture content: 0.8 wt%, moisture permeability: 115 g / (m 2 · 24 hr)] The first thermoplastic resin is passed through the laminating roll while injecting an aqueous adhesive between the polarizing film and the first thermoplastic resin film and between the polarizing film and the second thermoplastic resin film. Fat film / aqueous adhesive layer / polarizing film / aqueous adhesive layer / to obtain a laminated film made of a second thermoplastic resin film. Subsequently, the obtained laminated film was conveyed, passed through a hot air dryer, and heat-treated at 80 ° C. for 300 seconds to dry the aqueous adhesive layer, thereby obtaining a polarizing plate. In the aqueous adhesive, polyvinyl alcohol powder [trade name “Gosefimer” manufactured by Nippon Synthetic Chemical Industry Co., Ltd., average polymerization degree 1100] was dissolved in hot water at 95 ° C., and the concentration was 3%. An aqueous solution in which a crosslinking agent [sodium glyoxylate manufactured by Nippon Synthetic Chemical Industry Co., Ltd.] was mixed with a polyvinyl alcohol aqueous solution at a ratio of 1 part by weight to 10 parts by weight of the polyvinyl alcohol powder was used.
上記(A)で得られた偏光フィルムを連続的に搬送するとともに、長尺の第1熱可塑性樹脂フィルム〔コニカミノルタオプト(株)製のTACフィルム「KC2UAW」にハードコート層が形成されたフィルム、厚み:32.4μm、平衡水分率:1.9重量%、透湿度:455g/(m2・24hr)〕及び長尺の第2熱可塑性樹脂フィルム〔JSR(株)製の環状ポリオレフィン系樹脂フィルムである商品名「FEKB015D3」、厚み:15.1μm、平衡水分率:0.8重量%、透湿度:115g/(m2・24hr)〕を連続的に搬送し、偏光フィルムと第1熱可塑性樹脂フィルムとの間、及び偏光フィルムと第2熱可塑性樹脂フィルムとの間に水系接着剤を注入しながら、貼合ロール間に通して第1熱可塑性樹脂フィルム/水系接着剤層/偏光フィルム/水系接着剤層/第2熱可塑性樹脂フィルムからなる積層フィルムを得た。引き続き、得られた積層フィルムを搬送し、熱風乾燥機に通して80℃、300秒の加熱処理を行うことにより水系接着剤層を乾燥させて、偏光板を得た。上記の水系接着剤には、ポリビニルアルコール粉末〔日本合成化学工業(株)製の商品名「ゴーセファイマー」、平均重合度1100〕を95℃の熱水に溶解して得られた濃度3重量%のポリビニルアルコール水溶液に架橋剤〔日本合成化学工業(株)製のグリオキシル酸ナトリウム〕をポリビニルアルコール粉末10重量部に対して1重量部の割合で混合した水溶液を用いた。 (B) Preparation of polarizing plate While continuously transporting the polarizing film obtained in (A) above, the first thermoplastic resin film [Konica Minolta Opto Co., Ltd. TAC film “KC2UAW” Film with a coating layer, thickness: 32.4 μm, equilibrium moisture content: 1.9 wt%, moisture permeability: 455 g / (m 2 · 24 hr)] and a long second thermoplastic resin film [JSR Corporation ) Product name “FEKB015D3”, which is a cyclic polyolefin resin film manufactured in the following manner: thickness: 15.1 μm, equilibrium moisture content: 0.8 wt%, moisture permeability: 115 g / (m 2 · 24 hr)] The first thermoplastic resin is passed through the laminating roll while injecting an aqueous adhesive between the polarizing film and the first thermoplastic resin film and between the polarizing film and the second thermoplastic resin film. Fat film / aqueous adhesive layer / polarizing film / aqueous adhesive layer / to obtain a laminated film made of a second thermoplastic resin film. Subsequently, the obtained laminated film was conveyed, passed through a hot air dryer, and heat-treated at 80 ° C. for 300 seconds to dry the aqueous adhesive layer, thereby obtaining a polarizing plate. In the aqueous adhesive, polyvinyl alcohol powder [trade name “Gosefimer” manufactured by Nippon Synthetic Chemical Industry Co., Ltd., average polymerization degree 1100] was dissolved in hot water at 95 ° C., and the concentration was 3%. An aqueous solution in which a crosslinking agent [sodium glyoxylate manufactured by Nippon Synthetic Chemical Industry Co., Ltd.] was mixed with a polyvinyl alcohol aqueous solution at a ratio of 1 part by weight to 10 parts by weight of the polyvinyl alcohol powder was used.
偏光板の厚みT2は58.6μmであった。上記の方法に従って偏光板のカール量を測定したところ、-10mm(逆カール)であった。
The thickness T 2 of the polarizing plate was 58.6 μm. When the curl amount of the polarizing plate was measured according to the above method, it was -10 mm (reverse curl).
(C)プロテクトフィルム付偏光板の作製
上記(B)で得られた偏光フィルムを連続的に搬送するとともに、長尺のプロテクトフィルム〔基材フィルムがポリエチレンテレフタレートからなり、その上に(メタ)アクリル系粘着剤層を有するプロテクトフィルム、総厚みT1:57.3μm〕を連続的に搬送し、これらを重ねて貼合ロール間に通すことによりプロテクトフィルムと偏光板との積層体を上下から押圧して、プロテクトフィルム付偏光板を作製した。プロテクトフィルムは、その粘着剤層を介して偏光板の第1熱可塑性樹脂フィルム(TACフィルム)面に貼合されている。プロテクトフィルム1に接触する貼合ロールはSUSにクロムめっきが形成されたもの〔硬度100°〕、偏光板2に接触する貼合ロールはNBR(ニトリルゴム)からなるもの〔硬度70°〕を用いた。なお、貼合ロールによってプロテクトフィルムと偏光板との積層体に与えられる圧力(ニップ圧)は、0.1MPaであり、この数値は、下記の実施例及び比較例においてもおよそ同じである。プロテクトフィルム付偏光板のカール量を表1に示す。 (C) Production of polarizing plate with protective film While continuously transporting the polarizing film obtained in (B) above, a long protective film [base film is made of polyethylene terephthalate, on which (meth) acrylic Protective film having a PSA layer, total thickness T 1 : 57.3 μm] is continuously conveyed, and the laminate of the protective film and the polarizing plate is pressed from above and below by overlapping and passing between the bonding rolls. Thus, a polarizing plate with a protective film was produced. The protective film is bonded to the first thermoplastic resin film (TAC film) surface of the polarizing plate through the adhesive layer. The bonding roll that contacts the protective film 1 is made of SUS plated with chromium (hardness 100 °), and the bonding roll that contacts thepolarizing plate 2 is made of NBR (nitrile rubber) [hardness 70 °]. It was. In addition, the pressure (nip pressure) given to the laminated body of a protective film and a polarizing plate by a bonding roll is 0.1 MPa, and this numerical value is substantially the same also in the following Examples and Comparative Examples. Table 1 shows the curl amount of the polarizing plate with a protective film.
上記(B)で得られた偏光フィルムを連続的に搬送するとともに、長尺のプロテクトフィルム〔基材フィルムがポリエチレンテレフタレートからなり、その上に(メタ)アクリル系粘着剤層を有するプロテクトフィルム、総厚みT1:57.3μm〕を連続的に搬送し、これらを重ねて貼合ロール間に通すことによりプロテクトフィルムと偏光板との積層体を上下から押圧して、プロテクトフィルム付偏光板を作製した。プロテクトフィルムは、その粘着剤層を介して偏光板の第1熱可塑性樹脂フィルム(TACフィルム)面に貼合されている。プロテクトフィルム1に接触する貼合ロールはSUSにクロムめっきが形成されたもの〔硬度100°〕、偏光板2に接触する貼合ロールはNBR(ニトリルゴム)からなるもの〔硬度70°〕を用いた。なお、貼合ロールによってプロテクトフィルムと偏光板との積層体に与えられる圧力(ニップ圧)は、0.1MPaであり、この数値は、下記の実施例及び比較例においてもおよそ同じである。プロテクトフィルム付偏光板のカール量を表1に示す。 (C) Production of polarizing plate with protective film While continuously transporting the polarizing film obtained in (B) above, a long protective film [base film is made of polyethylene terephthalate, on which (meth) acrylic Protective film having a PSA layer, total thickness T 1 : 57.3 μm] is continuously conveyed, and the laminate of the protective film and the polarizing plate is pressed from above and below by overlapping and passing between the bonding rolls. Thus, a polarizing plate with a protective film was produced. The protective film is bonded to the first thermoplastic resin film (TAC film) surface of the polarizing plate through the adhesive layer. The bonding roll that contacts the protective film 1 is made of SUS plated with chromium (hardness 100 °), and the bonding roll that contacts the
<比較例1>
上記(C)の工程において、プロテクトフィルム1に接触する貼合ロールはNBR(ニトリルゴム)からなるもの〔硬度70°〕とし、偏光板2に接触する貼合ロールはSUSにクロムめっきが形成されたもの〔硬度100°〕とした以外は実施例1と同様にして、プロテクトフィルム付偏光板を作製した。プロテクトフィルム付偏光板のカール量を表1に示す。 <Comparative Example 1>
In the step (C), the bonding roll that contacts the protective film 1 is made of NBR (nitrile rubber) [hardness 70 °], and the bonding roll that contacts thepolarizing plate 2 has chrome plating formed on SUS. A polarizing plate with a protective film was produced in the same manner as in Example 1 except that the thickness was 100 [hardness]. Table 1 shows the curl amount of the polarizing plate with a protective film.
上記(C)の工程において、プロテクトフィルム1に接触する貼合ロールはNBR(ニトリルゴム)からなるもの〔硬度70°〕とし、偏光板2に接触する貼合ロールはSUSにクロムめっきが形成されたもの〔硬度100°〕とした以外は実施例1と同様にして、プロテクトフィルム付偏光板を作製した。プロテクトフィルム付偏光板のカール量を表1に示す。 <Comparative Example 1>
In the step (C), the bonding roll that contacts the protective film 1 is made of NBR (nitrile rubber) [hardness 70 °], and the bonding roll that contacts the
1 プロテクトフィルム、2,2a,2b,2c 偏光板、3 プロテクトフィルム付偏光板、5,5’ 貼合ロール、10 偏光フィルム、20 第1熱可塑性樹脂フィルム、30 第2熱可塑性樹脂フィルム、40 粘着剤層、50 セパレートフィルム。
1 protective film, 2, 2a, 2b, 2c polarizing plate, 3 polarizing plate with protective film, 5, 5 'bonding roll, 10 polarizing film, 20 first thermoplastic resin film, 30 second thermoplastic resin film, 40 Adhesive layer, 50 separate film.
Claims (8)
- 偏光板の片面にプロテクトフィルムを重ねて1対の貼合ロール間に通すことにより押圧する工程を含むプロテクトフィルム付偏光板の製造方法であって、
前記1対の貼合ロールにおいて、JIS K 6253に規定されるタイプAデュロメータ硬さ試験機により測定される、前記プロテクトフィルムに接触する貼合ロールの表面硬度H1と、前記偏光板に接触する貼合ロールの表面硬度H2とが、下記式(I):
H1>H2 (I)
の関係を満たす、製造方法。 A method for producing a polarizing plate with a protective film comprising a step of pressing a protective film on one side of the polarizing plate and pressing it between a pair of bonding rolls,
In the pair of bonding rolls, the surface hardness H 1 of the bonding roll contacting the protect film, measured by a type A durometer hardness tester defined in JIS K 6253, and contacting the polarizing plate. and the surface hardness of H 2 lamination rolls, the following formula (I):
H 1 > H 2 (I)
A manufacturing method that satisfies the above relationship. - 前記偏光板は、枚葉体としたときに、前記プロテクトフィルムが重ねられる側を凸とするカールを生じるものである、請求項1に記載の製造方法。 The manufacturing method according to claim 1, wherein when the polarizing plate is a sheet, the curling has a convex side on which the protective film is superimposed.
- 前記偏光板は、偏光フィルムと、その一方の面に積層される第1熱可塑性樹脂フィルムと、他方の面に積層される第2熱可塑性樹脂フィルムとを含む、請求項1又は2に記載の製造方法。 The said polarizing plate contains a polarizing film, the 1st thermoplastic resin film laminated | stacked on the one surface, and the 2nd thermoplastic resin film laminated | stacked on the other surface of Claim 1 or 2. Production method.
- 前記第1熱可塑性樹脂フィルムは、前記第2熱可塑性樹脂フィルムよりも温度23℃、相対湿度55%での平衡水分率が高い、請求項3に記載の製造方法。 The manufacturing method according to claim 3, wherein the first thermoplastic resin film has a higher equilibrium moisture content at a temperature of 23 ° C and a relative humidity of 55% than the second thermoplastic resin film.
- 前記第1熱可塑性樹脂フィルムと前記第2熱可塑性樹脂フィルムとは、前記平衡水分率の差が0.5重量%以上である、請求項4に記載の製造方法。 The manufacturing method according to claim 4, wherein the difference in equilibrium moisture content between the first thermoplastic resin film and the second thermoplastic resin film is 0.5 wt% or more.
- 前記プロテクトフィルムは、前記第1熱可塑性樹脂フィルム側に配置される、請求項3~5のいずれか1項に記載の製造方法。 The manufacturing method according to any one of claims 3 to 5, wherein the protective film is disposed on the first thermoplastic resin film side.
- 前記第1熱可塑性樹脂フィルムは、前記平衡水分率が1.5重量%以上である、請求項3~6のいずれか1項に記載の製造方法。 The manufacturing method according to any one of claims 3 to 6, wherein the first thermoplastic resin film has the equilibrium moisture content of 1.5 wt% or more.
- 前記偏光板の厚みが100μm以下である、請求項1~7のいずれか1項に記載の製造方法。 The manufacturing method according to any one of claims 1 to 7, wherein the polarizing plate has a thickness of 100 袖 m or less.
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