WO2013047687A1 - Vinyl polymer microparticles, method for producing same, resin composition, and optical material - Google Patents

Vinyl polymer microparticles, method for producing same, resin composition, and optical material Download PDF

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Publication number
WO2013047687A1
WO2013047687A1 PCT/JP2012/074944 JP2012074944W WO2013047687A1 WO 2013047687 A1 WO2013047687 A1 WO 2013047687A1 JP 2012074944 W JP2012074944 W JP 2012074944W WO 2013047687 A1 WO2013047687 A1 WO 2013047687A1
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Prior art keywords
vinyl polymer
fine particles
polymer fine
particles
film
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PCT/JP2012/074944
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French (fr)
Japanese (ja)
Inventor
泰隆 中谷
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株式会社日本触媒
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Application filed by 株式会社日本触媒 filed Critical 株式会社日本触媒
Priority to CN201280046793.XA priority Critical patent/CN103827148B/en
Priority to KR1020197024133A priority patent/KR102133923B1/en
Priority to KR1020147006945A priority patent/KR102141982B1/en
Priority to JP2013536398A priority patent/JP5740479B2/en
Publication of WO2013047687A1 publication Critical patent/WO2013047687A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F212/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0268—Diffusing elements; Afocal elements characterized by the fabrication or manufacturing method
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/01—Processes of polymerisation characterised by special features of the polymerisation apparatus used
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/12—Polymerisation in non-solvents
    • C08F2/16—Aqueous medium
    • C08F2/18—Suspension polymerisation
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/10—Esters
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L101/00—Compositions of unspecified macromolecular compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L25/00—Compositions of, homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Compositions of derivatives of such polymers
    • C08L25/02—Homopolymers or copolymers of hydrocarbons
    • C08L25/04—Homopolymers or copolymers of styrene
    • C08L25/08—Copolymers of styrene
    • C08L25/14—Copolymers of styrene with unsaturated esters
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/04—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F230/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and containing phosphorus, selenium, tellurium or a metal
    • C08F230/04—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and containing phosphorus, selenium, tellurium or a metal containing a metal
    • C08F230/08—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and containing phosphorus, selenium, tellurium or a metal containing a metal containing silicon
    • C08F230/085—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and containing phosphorus, selenium, tellurium or a metal containing a metal containing silicon the monomer being a polymerisable silane, e.g. (meth)acryloyloxy trialkoxy silanes or vinyl trialkoxysilanes
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0205—Diffusing elements; Afocal elements characterised by the diffusing properties
    • G02B5/0236—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place within the volume of the element
    • G02B5/0242—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place within the volume of the element by means of dispersed particles

Definitions

  • the present invention relates to vinyl polymer fine particles with reduced coarse particles, and in particular, vinyl polymer fine particles in which the number of particles more than twice the average particle size is extremely reduced by improving the suspension polymerization method, and the production thereof
  • the present invention relates to a method, a resin composition containing the vinyl polymer fine particles, and an optical material.
  • the fine particles used in these optical films are particularly desired to have a small content of coarse particles. This is because coarse particles cause scratches on the film surface or reduce light diffusion performance.
  • the necessity of removing even coarse particles having a size close to the average particle size, such as about twice the average particle size, is increasing.
  • Patent Document 1 discloses that the average particle size is obtained by performing wet classification from a dispersion of polymer particles obtained by seed polymerization, followed by dry classification. A technique for reducing coarse particles having a size of twice or more the particle diameter is disclosed.
  • the polymer particles obtained by the seed polymerization method have a sharp particle size distribution and are difficult to meet the above requirements.
  • the amount of fine particles as an additive for film is increasing year by year, and it is strongly required to be cheaper as the particle diameter becomes finer. It is necessary to avoid it.
  • vinyl polymer fine particles that can be used for film additives including optical films such as light diffusion films, and coarse particles having a size about twice the average particle size are below a predetermined value. It is not easy to obtain particles that are suppressed and have a relatively wide particle size distribution, and a method for obtaining the particles has not been known.
  • the present invention based on the above prior art, it is intended to provide vinyl polymer fine particles suitable as an additive for film having a predetermined particle size distribution and having a reduced number of coarse particles, and a method for producing the fine particles. To do.
  • the present invention also provides a resin composition containing the fine particles, an optical film obtained from the resin composition, and a light diffusion film.
  • the polymer is fine particles of a vinyl polymer having an aromatic ring and that the inorganic component in the vinyl polymer is 2% by mass or less.
  • the vinyl polymer fine particles of the present invention are preferably an additive for optical materials and / or an additive for films. In particular, it is preferable to be added to an optical film or to be used as a light diffusing agent.
  • the present invention includes an optical film obtained by applying a coating solution containing the resin composition on at least one surface of the base film, particularly a light diffusion film.
  • the number of coarse particles is preferably 170 or less, more preferably 160 or less, and even more preferably 150 or less, out of 1 million vinyl polymer fine particles.
  • the variation coefficient (CV value) of the volume-based particle diameter of the vinyl polymer fine particles of the present invention is 10% or more. This is because when used as a light diffusing agent, it has excellent light diffusibility. For the same reason, 20% or more is preferable, more preferably 25% or more, and particularly preferably 30% or more.
  • the upper limit value of the coefficient of variation of the particle diameter is not particularly limited. However, since the light diffusibility may be lowered even if the coefficient of variation is too large, it is preferably 50% or less, more preferably 40% or less.
  • the monomer component used in synthesizing the vinyl polymer fine particles of the present invention preferably contains a vinyl monomer having an aromatic ring.
  • the resulting vinyl polymer fine particles have an aromatic ring and become finely charged fine particles.
  • the dry classification may cause clogging of pipes due to adhesion in the apparatus. It happens and the work stops, so it is not easy to remove only the coarse particles.
  • the wet classification is as described above.
  • vinyl monomer having an aromatic ring examples include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, ⁇ -methylstyrene, p-methoxystyrene, p-tert-butylstyrene, p-phenylstyrene, o Monofunctional styrene monomers such as chlorostyrene, m-chlorostyrene, p-chlorostyrene, o-ethylvinylbenzene, m-ethylvinylbenzene, p-ethylvinylbenzene; divinylbenzene, divinylnaphthalene, and derivatives thereof
  • the aromatic divinyl compound can be used, and can be used alone or in combination of two or more.
  • a (meth) acrylic monomer can be used instead of or in addition to the monomer having an aromatic ring.
  • examples of the (meth) acrylic monomer include acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, stearyl acrylate, 2-ethylhexyl acrylate, and tetrahydrofluorate acrylate.
  • Monofunctional such as furyl, methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate
  • (meth) acrylic-type monomer is mentioned, it is not limited to these. These monofunctional (meth) acrylic monomers may be used alone or in combination of two or more.
  • Crosslinkable (meth) acrylic monomers include trimethylolpropane triacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, decaethylene glycol dimethacrylate, pentadecaethylene glycol dimethacrylate (Meth) acrylic monomers such as ethylene glycol dimethacrylate pentaethylene glycol, 1,3-butylene dimethacrylate, allyl methacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, diethylene glycol dimethacrylate And may be used alone or in combination.
  • crosslinking agents such as N, N-divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfonic acid and the like, polybutadiene, and JP-B-57-56507, JP-A-59-221304, JP-A-59-221305
  • the reactive polymers described in JP-A-59-221306 and JP-A-59-221307 may be used.
  • vinyl polymer fine particles preferable in the present invention, vinyl polymer fine particles (embodiment (i)) obtained by copolymerizing a monomer component containing a styrene monofunctional monomer and a crosslinkable (meth) acrylic monomer, or It is a vinyl polymer fine particle (embodiment (ii)) obtained by copolymerizing a monomer component containing a monofunctional (meth) acrylic monomer and an aromatic divinyl compound.
  • the styrene monofunctional monomer is preferably 10 to 70% by mass
  • the crosslinkable (meth) acrylic monomer is 0 to 60% by mass
  • the other monomers are preferably 0 to 40% by mass.
  • styrene is preferred as the styrene monofunctional monomer
  • trimethylolpropane trimethacrylate and ethylene glycol dimethacrylate are preferred as the crosslinkable (meth) acrylic monomer.
  • the monofunctional (meth) acrylic monomer is 0 to 60% by mass
  • the aromatic divinyl compound is 10 to 70% by mass
  • the other monomers are 0 to 40% by mass.
  • the monofunctional (meth) acrylic monomer is preferably methyl methacrylate
  • the aromatic divinyl compound is preferably divinylbenzene.
  • Embodiment (i) is preferable as the vinyl polymer fine particles of the present invention, and among them, those obtained by copolymerizing a monomer component containing styrene and a crosslinkable (meth) acrylic monomer are more preferable.
  • the vinyl polymer fine particles of the present invention contain no inorganic component or contain 2% by mass or less.
  • the suspension polymer is used in suspension polymerization.
  • the size of the droplets does not advance and coarse particles in the resulting vinyl polymer fine particles may increase.
  • the amount of the inorganic component is the mass of ash after the particles are heated from room temperature in an oxidizing atmosphere such as air and heated at 800 ° C. for 1 hour.
  • the vinyl polymer fine particles of the present invention are preferably fine particles obtained by a suspension polymerization method. This is because it is cheaper than seed polymerization and dispersion polymerization, is economically advantageous as fine particles for optical films, and can easily control the coefficient of variation of particle diameter to 10% or more.
  • the production method of the present invention includes a droplet formation step and a polymerization step in which a mixed solution containing water, a monomer component and a radical polymerization initiator is introduced into a suspension device and suspended to form droplets,
  • the droplet forming process includes at least a stage (1) and a stage (2), and the shear force in the stage (2) is larger than the shear force in the stage (1).
  • the suspension method for producing droplets by forcibly stirring and suspending a mixed solution containing a monomer component, a radical polymerization initiator and water is not particularly limited.
  • a method of directly suspending the entire amount of the mixture by stirring or the like supplying a mixed solution to a container containing the mixed solution and a suspension device (also referred to as an external suspension device) provided in the middle of a circulation line connected to the container.
  • suspension method is preferred from the viewpoint of suspension efficiency. More specifically, the latter method uses a device in which a suspension device is installed in the middle of a circulation line connected to the reaction vessel, and introduces the above mixed solution from the reaction vessel to the suspension device to give a shearing force.
  • the shearing force can be controlled by changing the suspension conditions in the suspension device, for example, the discharge amount of the external suspension device and the stirring rotation speed in steps (1) and (2).
  • step (2) When the shearing force is controlled by the discharge amount, the total amount of the mixed solution (reaction solution used for polymerization after suspension) introduced into the suspension device is V (kg), and the discharge amount from the suspension device is v (m 3 / hr), v / V in step (2) may be made larger than v / V in step (1).
  • step (1) suspension is performed at a lower discharge rate than in step (2), and in step (2) suspension is performed at a higher discharge amount than in step (1).
  • step (1) droplets are formed at a lower speed than in step (2), and in step (2), droplets are formed at a higher speed than in step (1).
  • the external suspension device is not particularly limited, but a pipeline mixer or an ebara milder is preferable. A pipeline mixer is more preferable.
  • the pipeline mixer of the present invention includes both pipeline mixers and pipeline homomixers.
  • the droplet forming process is performed as follows. Using a device in which a pipeline mixer is installed in the middle of the circulation line connected to the reaction vessel, the mixture is introduced from the reaction vessel into the pipeline mixer, stirred by applying a shearing force, and then again from the pipeline mixer to the reaction vessel. The operation of returning to is continuously repeated. At this time, the process of manufacturing the droplet is divided into two stages.
  • V (kg) and the discharge amount of the pipeline mixer is v (m 3 / hr)
  • V / V in step (2) is made larger than v / V in (1).
  • the same may be performed using the stirring rotation speed of the pipeline mixer as an index.
  • V / V is preferably 0.01m 3 / (hr ⁇ kg) or more stages (1) of the droplet formation process is preferably 0.10m 3 / (hr ⁇ kg) or less. More preferably 0.02m 3 / (hr ⁇ kg) or more, 0.05m 3 / (hr ⁇ kg) or less.
  • V / V is preferably 0.05m 3 / (hr ⁇ kg) or more stages (2), is preferably 0.15m 3 / (hr ⁇ kg) or less.
  • the ratio of the magnitude of v / V in step (2) to v / V in step (1) is preferably 1.01 or more, and more preferably 1.5 or less. More preferably, it is 1.05 times or more and 1.2 times or less.
  • this ratio is less than 1.01, the effect of forming droplets in two stages may be reduced, and if it exceeds 1.5, the amount of coarse particles is below a predetermined value, particularly when the average particle size is large. However, there is a risk that it will be relatively large. In other words, if the number of passes is decreased to control the average particle size so as not to be too small, the amount of coarse particles becomes relatively large. On the other hand, if the number of passes is increased, the average particle size may be too small.
  • the preferred range of v / V in step (1) and step (2) above, and the preferred range of the ratio of v / V magnitude in step (2) to v / V in step (1) are suspensions.
  • a preferable range of the ratio of the rotation speed of the stage (2) to the rotation speed of the stage (1) is that of the stage (2) with respect to v / V of the stage (1). This is the same as the preferable range of the ratio of v / V.
  • the circulation to the external suspension device is preferably repeated tens of times (the number of passes is set to tens of times).
  • the number of circulations (also referred to as the number of passes) is not particularly limited, but is preferably 5 times or more and 100 times or less in both step (1) and step (2). If it is less than 5 times, the treatment effect at each stage may be insufficient. On the other hand, if it exceeds 100 times, productivity may be reduced. More preferably, it is 10 times or more and 60 times or less.
  • Water is used as a medium that provides a field for suspension polymerization. It is inexpensive and safe and is optimal for suspension polymerization of oil-soluble monomers. It is also suitable for removing polymerization heat.
  • the suspension When polymerizing the suspension, there are a case where the suspension is heated and polymerized as it is, and a case where water is further added to the suspension and then heated, both of which can be employed.
  • water When the suspension is heated as it is, water is preferably about 60 to 80 parts by mass in 100 parts by mass of the suspension.
  • water When adding water to the suspension, water is preferably about 40 to 60 parts by mass in 100 parts by mass of the suspension before dilution, and after addition of water, 60 to 60 parts of water in 100 parts by mass of the polymerization reaction solution is added. About 90 parts by mass is preferable.
  • a water-soluble organic solvent may be used.
  • the water-soluble organic solvent in the range of 0.1 to 10 parts by mass with respect to 100 parts by mass of the monomer component, the particle diameter of oil droplets can be reduced during suspension.
  • a more preferable amount of the water-soluble organic solvent is 0.1 to 5 parts by mass, more preferably 1 to 5 parts by mass with respect to 100 parts by mass of the monomer component.
  • the water-soluble organic solvent include lower alcohols; ketones such as acetone and methyl ethyl ketone; esters such as ethyl acetate; ethers such as dioxane and diethyl ether.
  • alcohols having 4 or less carbon atoms are preferred from the viewpoints that they have a low boiling point, are easily volatilized, and hardly remain in particles after drying, and are easy to handle.
  • the lower alcohol having 4 or less carbon atoms include methyl alcohol, ethyl alcohol, isopropyl alcohol (IPA), n-propyl alcohol, n-butyl alcohol, isobutyl alcohol, s-butyl alcohol and t-butyl alcohol.
  • IPA having 3 carbon atoms and n-propyl alcohol are preferable.
  • IPA having a lower boiling point is most preferable because it easily volatilizes when polymer fine particles are dried.
  • radical polymerization initiator conventionally known oil-soluble peroxides and azo compounds can be used.
  • peroxides include benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, orthochlorobenzoyl peroxide, orthomethoxybenzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxydicarbonate, cumene hydroperoxide, cyclohexanone peroxide.
  • examples thereof include oxide, t-butyl hydroperoxide, and diisopropylbenzene hydroperoxide.
  • Examples of the azo compound include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2,3-dimethylbutyro). Nitrile), 2,2'-azobis- (2-methylbutyronitrile), 2,2'-azobis (2,3,3-trimethylbutyronitrile), 2,2'-azobis (2-isopropylbutyro) Nitrile), 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2- (carbamoylazo) isobutyronitrile, 4 4,4'-azobis (4-cyanovaleric acid), dimethyl-2,2'-azobisisobutyrate, and the like.
  • the polymerization initiator is preferably used in the range of 0.1 to 5 parts by mass with respect to 100 parts by mass of the monomer component. More preferably, it is 1 to 5 parts by mass. Moreover, since most of the polymerization initiators are oil-soluble, it is preferable to add them to water after dissolving them in the monomer component in advance.
  • Dispersion stabilizer In order to stabilize the oil droplets in the suspension and facilitate the polymerization reaction, it is preferable to use a dispersion stabilizer.
  • the dispersion stabilizer include polyvinyl alcohol, gelatin, tragacanth, starch, methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, sodium polyacrylate, polysodium methacrylate, and the like; anionic surfactants; nonionic surfactants Cationic surfactant; Zwitterionic surfactant, other alginate, zein, casein, barium sulfate, calcium sulfate, barium carbonate, magnesium carbonate, calcium phosphate, talc, clay, diatomaceous earth, bentonite, titanium hydroxide, water Sodium oxide, metal oxide powder, etc. are used.
  • anionic surfactant examples include fatty acid salts such as sodium oleate and potassium castor oil; alkyl sulfate ester salts such as sodium lauryl sulfate and ammonium lauryl sulfate; alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate; alkylnaphthalene Sulfonate; Alkane sulfonate; Dialkyl sulfosuccinate; Alkyl phosphate ester salt; Naphthalene sulfonate formalin condensate; Polyoxyethylene alkyl ether sulfate; Polyoxyethylene phenyl ether sulfate salt; Polyoxyethylene alkyl sulfate ester Examples include salts.
  • Nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxysorbitan fatty acid ester, polyoxyethylene alkylamine, glycerin fatty acid ester, oxyethylene- An oxypropylene block copolymer etc. are mentioned.
  • Examples of the cationic surfactant include alkylamine salts such as laurylamine acetate and stearylamine acetate; quaternary ammonium salts such as lauryltrimethylalkylammonium chloride.
  • Examples of amphoteric surfactants include lauryl dimethylamine oxide.
  • the amount of the dispersion stabilizer used is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, and still more preferably 1 to 2 parts by mass with respect to 100 parts by mass of the monomer component.
  • a monomer component, water, a radical polymerization initiator, and if necessary, a dispersion stabilizer and / or a water-soluble organic solvent are added to a reaction vessel to form a suspension.
  • the order of adding each component at this time is not particularly limited. An example is as follows. First, when using water and a dispersion stabilizer in a container, the dispersion stabilizer is charged. The dispersion stabilizer may be charged after being dissolved in water, or may be dissolved by stirring well in a container. Next, a monomer component and a radical polymerization initiator are added to the container. Of course, this order may be reversed.
  • droplet formation is performed by the method and conditions described above. That is, the mixed solution in the reaction vessel is passed through a suspension device (for example, a pipeline mixer) using a pump or the like to produce a suspension.
  • a suspension device for example, a pipeline mixer
  • polymerization may be performed. Specifically, the circulation line is blocked and heated while replacing the inside of the reaction vessel with an inert gas such as nitrogen to raise the temperature of the suspension.
  • the polymerization temperature is preferably 60 to 100 ° C., more preferably 65 to 95 ° C., and further preferably 70 to 90 ° C.
  • the polymerization reaction is preferably performed for 2 to 7 hours, more preferably 2.5 to 5 hours, and further preferably 3 to 4.5 hours.
  • the polymerization reaction is preferably performed in the pH range of 4-10.
  • a known additive may be added during suspension polymerization or after suspension polymerization as long as the object of the present invention is not impaired.
  • Specific examples include pigments, plasticizers, polymerization stabilizers, fluorescent brighteners, magnetic powders, ultraviolet absorbers, antistatic agents, and flame retardants.
  • the vinyl polymer fine particles of the present invention do not need to be classified because coarse particles are reduced, but it is preferable to remove foreign matters by a known method such as filtration.
  • crushing is a process of returning (aggregating) particles aggregated during drying to the original primary particles, and is not a process of further reducing (breaking) the primary particles.
  • the vinyl polymer fine particles of the present invention obtained by utilizing suspension polymerization have a coefficient of variation in particle diameter of a predetermined value or more, and the number of coarse particles is reduced. Therefore, the vinyl polymer fine particles of the present invention are useful for various uses, particularly as an additive for optical materials and an additive for films.
  • the additive for optical materials include, for example, a light diffusing film and a light guide plate used for LCDs, or a light diffusing agent and an anti-blocking agent contained in an optical resin used for PDP, EL display, touch panel and the like.
  • Suitable additives include anti-blocking agents for various optical films, lubricants, and the like.
  • an additive for films various additives (an antiblocking agent, a lubricant, a light diffusing agent, etc.) of various films other than an optical film or an optical film are mentioned as a preferable thing.
  • an additive for optical films is more preferred.
  • the vinyl polymer particles of the present invention are particularly preferred as a light diffusing agent for optical films such as light diffusing films, antiglare films, and antireflection films.
  • the volume average particle diameter of the vinyl polymer fine particles is preferably 10 ⁇ m or less, and particularly preferably 3.5 ⁇ m or less.
  • the vinyl polymer fine particles of the present invention can be suitably used for applications other than those described above, such as optical materials.
  • additive for electrostatic image developing toner additive for decorative plate, additive for artificial marble, column filler for chromatography, gap adjuster for liquid crystal display panel, display particle for coulter counter, carrier for immunodiagnostic drug, It is also suitably used as a cosmetic additive.
  • the resin composition of the present invention essentially contains the above-described vinyl polymer fine particles of the present invention. Further, the resin composition of the present invention may contain a transparent binder resin.
  • the amount of fine particles contained in the resin composition may be appropriately determined according to the use of the resin composition and desired properties, but is usually used for an optical material such as an optical use such as a light diffusion plate.
  • an optical material such as an optical use such as a light diffusion plate.
  • (Aspect (I) below) is preferably 0.01 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin. More preferably, it is 0.05 mass part or more, More preferably, it is 0.1 mass part or more, More preferably, it is 10 mass part or less, More preferably, it is 5 mass part or less.
  • the binder resin 100 mass It is preferable to set it as 5 to 600 mass parts with respect to a part. More preferably, it is 10 to 500 mass parts, More preferably, it is 20 to 400 mass parts.
  • the content of the vinyl polymer fine particles is too large, the strength of the molded product obtained using this resin composition may be reduced. On the other hand, when the content is too small, the use of the vinyl polymer fine particles may result. In some cases, it is difficult to obtain an effect (such as light diffusibility).
  • the transparent binder resin contained in the resin composition is not particularly limited, and any resin used as a binder resin in the field can be used.
  • a polyester resin such as polyethylene terephthalate or polyethylene naphthalate, an acrylic resin, a polystyrene resin, a polyether sulfone resin, a polyurethane resin, a polycarbonate resin, Polyolefin resins such as polysulfone resins, polyether resins, polymethylpentene resins, polyether ketone resins, (meth) acrylonitrile resins, polypropylene resins, norbornene resins, amorphous polyolefin resins, polyamide resins , Polyimide resin, and triacetylcellulose tree Examples include fats.
  • a member to be molded is formed by laminating (coating, laminating, etc.) the resin composition of the present invention on a previously prepared plate-like or film-like substrate surface.
  • the binder resin include acrylic resins, polypropylene resins, polyvinyl alcohol resins, polyvinyl acetate resins, polystyrene resins, polycarbonate resins, fluororesins, silicone resins, and polyurethane resins.
  • the resin composition of the present invention may contain other additives as necessary, as long as the effects of the present invention are not impaired, in addition to the vinyl polymer fine particles and the transparent binder resin.
  • other additives include various additives such as an ultraviolet absorber, a crosslinking agent, a fluorescent brightening agent, and a flame retardant for enhancing physical properties such as light resistance and UV resistance. These may use only 1 type and may use 2 or more types together.
  • the vinyl polymer fine particles of the present invention are excellent in light diffusibility, and can exhibit excellent optical properties such as high luminance and high transmittance. Therefore, it is particularly preferably used as a light diffusing agent for optical materials such as a light diffusing film and a light diffusing plate for uniformly diffusing light from the light source on the image display surface in the image display device.
  • the shape of the molded body is not limited to a film shape or a plate shape, and may be a molded body such as a column, a cone, or a sphere.
  • the form when the molded product obtained from the resin composition of the present invention is a film-shaped molded product such as a light diffusing film, the form has a planar portion, and the vinyl polymer fine particles are formed by a binder resin.
  • the form which has the structure formed by fixing at least in part.
  • the resin composition itself is formed into a plate shape (light diffusing plate), (ii) a part of the plate-like or film-like substrate surface prepared in advance or on the entire surface from the resin composition And the like (stacking and integrating layers) (optical film such as a light diffusion film).
  • the vinyl polymer fine particles according to the present invention are dispersed and fixed in the transparent binder resin, so that excellent optical properties can be exhibited.
  • the above-mentioned “having a planar portion” generally means that a substantially flat surface portion having a certain area spread, such as a plate shape or a film shape of an optical member (although it is said that it is the main component of the shape (including the case of having irregularities on the micron level), the present invention is not limited to such an embodiment, and even if it is not the main component, It is sufficient that at least a part of the surface is substantially flat.
  • fine projections based on the presence of the vinyl polymer fine particles of the present invention are formed at a high density on the planar portion in order to further exhibit the light diffusion performance. Preferably it is.
  • the resin composition of the present invention is extruded while melting and kneading with a known extruder, and is in the form of a plate (thickness: 1 mm or more) and a film. And a method of forming into a shape (thickness: 1 to less than 1000 ⁇ m).
  • a molded body formed into a film shape can be formed into a thin film-like stretched film (thickness: 5 to 100 ⁇ m) by stretching in a uniaxial or biaxial direction using a conventionally known stretching apparatus. .
  • the resin composition is preferably mixed and dispersed in advance with the vinyl polymer fine particles of the present invention in a binder resin.
  • the additive may be mixed with the resin composition.
  • the binder resin with the vinyl polymer fine particles and additives they may be mixed and used when fed to the extruder, or melted and kneaded with a part of the binder resin to prepare a master batch. You may use after producing. From the viewpoint of preventing segregation of the vinyl polymer fine particles in the molded product, it is preferably used as a master batch.
  • Examples of the method for obtaining the molded article having the form (ii) include a method of laminating a layer made of the resin composition of the present invention on a previously prepared base material surface.
  • the lamination method is not particularly limited, and the resin composition may be an organic solvent (for example, alcohols such as methanol, ethanol and isopropyl alcohol; ketones such as acetone and methyl ethyl ketone; aromatic hydrocarbons such as toluene and xylene; ethyl acetate and the like).
  • a base material eg, polyesters such as polyethylene terephthalate and polyethylene naphthalate); triacetyl cellulose; olefin polymers such as cyclopolyolefin and amorphous polyolefin; polymethyl methacrylate, (Meth) acrylate resin-based polymers such as (meth) acrylate having a lactone ring structure; polystyrene resin; polycarbonate resin, etc.) may be applied (coating method, cast method, etc.). Specific coating methods include known laminating methods such as reverse roll coating, gravure coating, die coating, comma coating, and spray coating. In addition, you may provide an easily bonding layer in a base material.
  • olefin polymers such as cyclopolyolefin and amorphous polyolefin
  • polymethyl methacrylate, (Meth) acrylate resin-based polymers such as (meth) acrylate having a lactone ring structure
  • the substrate on which the resin composition is laminated may be stretched uniaxially or biaxially by a conventionally known stretching apparatus to form a stretched film.
  • the application timing of the resin composition is not particularly limited, and a method (in-line method) of forming the resin composition layer at any stage of the film production process can be adopted.
  • the method (offline system) of forming the layer which consists of a resin composition of this invention on the said film is also employable.
  • the film thickness of the optical film such as the light diffusion film according to the present invention is preferably 300 ⁇ m or less, and the thickness of the light diffusion plate is preferably 8 mm or less.
  • An optical film such as a light diffusing film can also be produced according to the production method of the form (i). Moreover, you may extend
  • a volume-based average particle diameter and a coefficient of variation of the particle diameter were determined using a precision particle size distribution analyzer (“Coulter Multisizer III type”; manufactured by Beckman Coulter, Inc.).
  • the variation coefficient of the particle diameter is a value obtained by the following formula.
  • Variation coefficient of particle diameter (%) 100 ⁇ (standard deviation of particle diameter / volume average particle diameter)
  • a dispersion (0.05 parts in terms of particles) or 0.05 parts of particle powder was mixed with a 1.4% by mass aqueous surfactant solution (“Neoperex (registered trademark) G-15”; dodecylbenzenesulfone). 17.5 parts of sodium acid (manufactured by Kao Corporation) was added and dispersed by ultrasonic waves for 10 minutes.
  • Neoperex registered trademark
  • G-15 dodecylbenzenesulfone
  • a suspension was obtained as follows. That is, in a pipeline mixer, v / V (v is the discharge amount of the mixer (m 3 / hr), V is the total amount of the mixed solution (kg)) under a constant condition of 0.0283 m 3 / (hr ⁇ kg) Then, in terms of the discharge amount, circulation (stage (1)) is performed for a time corresponding to 24 passes from the total amount of the above mixed liquid, and then, the time corresponding to 25 passes is v / V of 0.0322 m 3 / (hr (Kg) was circulated under certain conditions (stage (2)) to obtain a uniform suspension.
  • Fine particles were taken out from the obtained dispersion by centrifugal sedimentation, dried at 80 ° C. with a dryer, and the drying was completed when the water content was 0.5% or less.
  • the dried fine particles were coarsely crushed by a mill, and a powder crushed by a pulverizer was obtained.
  • This powder had a volume average particle size of 3.1 ⁇ m, a coefficient of variation of 36.3%, a number of coarse particles (per 1 million particles) of 113, and a maximum particle size of 9.3 ⁇ m.
  • Table 2 shows the characteristic values of the dispersion
  • Table 3 shows the characteristic values after pulverization.
  • Experimental example 2 After preparing a mixed solution in the same manner as in Experimental Example 1, a uniform suspension was obtained in two steps in the same manner as in Experimental Example 1, except that a suspension was prepared under the conditions shown in Table 1. Thereafter, polymerization was carried out in the same manner as in Experimental Example 1 to obtain a dispersion containing vinyl polymer fine particles having a volume average particle size of 3.0 ⁇ m and a coefficient of variation of 36.5%.
  • Fine particles were taken out from the obtained dispersion by centrifugal sedimentation, dried at 80 ° C. with a dryer, and the drying was completed when the water content was 0.5% or less.
  • the dried fine particles were coarsely crushed by a mill, and a powder crushed by a pulverizer was obtained.
  • This powder had a volume average particle size of 3.0 ⁇ m, a coefficient of variation of 35.9%, a number of coarse particles (per 1 million particles) of 95, and a maximum particle size of 8.0 ⁇ m.
  • Table 2 shows the characteristic values of the dispersion
  • Table 3 shows the characteristic values after pulverization.
  • Experimental example 3 After preparing a mixed solution in the same manner as in Experimental Example 1, a suspension was prepared in one step under the conditions shown in Table 1. Otherwise, polymerization was carried out in the same manner as in Experimental Example 1 to obtain a dispersion containing vinyl polymer fine particles having a volume average particle diameter of 3.1 ⁇ m and a coefficient of variation of 37.0%. Using a part of the dispersion, powder was produced in the same manner as in Experimental Example 1. Table 2 shows the characteristic values of the dispersion, and Table 3 shows the characteristic values after pulverization.
  • Experimental Example 4 After preparing a mixed solution in the same manner as in Experimental Example 1, a suspension was prepared in one step under the conditions shown in Table 1. Otherwise, polymerization was performed in the same manner as in Experimental Example 1 to obtain a dispersion containing vinyl polymer fine particles having a volume average particle size of 3.0 ⁇ m and a coefficient of variation of 39.4%. Using a part of the dispersion, powder was produced in the same manner as in Experimental Example 1. Table 2 shows the characteristic values of the dispersion, and Table 3 shows the characteristic values after pulverization.
  • the resulting powder was classified using an electron filter having an opening of 5 ⁇ m, but clogged immediately and could not be classified. It is thought that coarse particles are the cause.
  • the obtained powder was classified using an airflow classifier (“Micron Separator”, manufactured by Hosokawa Micron Corporation), but could not be classified due to clogging in the piping. It is thought that because the vinyl polymer particles are easily charged, they aggregate and block the piping.
  • Experimental Example 5 After preparing a mixed solution in the same manner as in Experimental Example 1, a suspension was prepared in one step under the conditions shown in Table 1. Otherwise, polymerization was carried out in the same manner as in Experimental Example 1 to obtain a dispersion containing vinyl polymer fine particles having a volume average particle diameter of 2.8 ⁇ m and a coefficient of variation of 35.0%. Using a part of the dispersion, powder was produced in the same manner as in Experimental Example 1. Table 2 shows the characteristic values of the dispersion, and Table 3 shows the characteristic values after pulverization.
  • Experimental Example 6 After preparing a mixed solution in the same manner as in Experimental Example 1, a suspension was prepared in two stages under the conditions shown in Table 1 to obtain a uniform suspension. Thereafter, polymerization was carried out in the same manner as in Experimental Example 1 to obtain a dispersion containing vinyl polymer fine particles having a volume average particle diameter of 3.1 ⁇ m and a coefficient of variation of 31.7%. Using a part of the dispersion, powder was produced in the same manner as in Experimental Example 1. Table 2 shows the characteristic values of the dispersion, and Table 3 shows the characteristic values after pulverization.
  • Experimental Example 7 The dispersion obtained in Experimental Example 6 was decanted, and the resulting precipitate was dispersed again in water, and the decantation was repeated to remove fine particles. The average particle size was 2.9 ⁇ m, and the coefficient of variation was 26.2%. A dispersion containing vinyl polymer fine particles was obtained. Using a part of the dispersion, powder was produced in the same manner as in Experimental Example 1. Table 2 shows the characteristic values of the dispersion, and Table 3 shows the characteristic values after pulverization.
  • the obtained monomer emulsion was added to an emulsion of polymerizable polysiloxane particles and stirred. Two hours after the addition of the monomer emulsion, the emulsion was sampled and observed with a microscope, and it was confirmed that the polymerizable polysiloxane particles absorbed the monomer emulsion and were enlarged.
  • Reference example 2 A reaction kettle equipped with a cooling line, a stirrer, a thermometer and a dripping port was charged with 75 parts of melamine, 75 parts of benzoguanamine, 290 parts of formalin with a concentration of 37% and 1 part of an aqueous sodium carbonate solution with a concentration of 10%, and an amino resin precursor A forming mixture was prepared. The mixture was heated to 85 ° C. while stirring and then held at 85 ° C. for 1.5 hours to obtain an initial condensate.
  • a surfactant solution prepared by dissolving 7.5 parts of sodium dodecylbenzenesulfonate in 2455 parts of ion-exchanged water is maintained at 50 ° C., and the initial condensate is added under stirring, and the amino resin precursor milk is added. A turbid liquid was obtained.
  • 290 parts of a 5% concentration of dodecylbenzenesulfonic acid aqueous solution was added and condensed and crosslinked at 70 to 90 ° C. to obtain a suspension containing amino resin crosslinked particles. This suspension was filtered, and the residue was dried to obtain a powder of amino resin crosslinked particles.
  • Table 3 The characteristic values of this powder are shown in Table 3.
  • the surface of the obtained light diffusion film (sample: 148 mm long, 210 mm wide rectangular shape) is visually observed to see if there are any defects due to coarse particles.
  • the evaluation was evaluated as ⁇ when the number was 15 or less, and X when there were more than 15 defects.
  • luminance unevenness was evaluated.
  • a backlight unit of a liquid crystal television “AQUAS (registered trademark) LC-37AD” manufactured by Sharp Corporation was used.
  • This backlight unit includes a light source and a light diffusion plate.
  • the light diffusing film of each experimental example is placed on the light diffusing plate of the backlight unit, a luminance meter is installed at a position 50 cm away from the light diffusing film, and the front luminance is measured at any nine locations. Unevenness was evaluated. No brightness unevenness was indicated by ⁇ , slight brightness unevenness was indicated by ⁇ , and brightness unevenness was indicated by ⁇ .
  • the vinyl polymer fine particles of the present invention obtained by utilizing suspension polymerization have a reduced number of coarse particles despite having a relatively wide particle size distribution. Therefore, the vinyl polymer fine particles of the present invention are used in various applications, for example, a light diffusing sheet or light guide plate used for LCDs or the like, or a light diffusing agent or anti-light agent contained in an optical resin used for PDP, EL display and touch panel. It is also suitably used for optical applications such as additives such as blocking agents, anti-blocking agents for various films, lubricants, and the like.

Abstract

The purpose of the present invention is to provide vinyl polymer microparticles that are ideal as an additive for a film as the particles have a specific grain size distribution, but the number of coarse particles is reduced. Also provided is a method for producing these microparticles. Moreover, the present invention provides a resin composition comprising the microparticles, an optical film obtained from the resin composition, and a light-diffusing film. With respect to these vinyl polymer microparticles, the particle diameter variation coefficient of a volume standard is at least 10% and the number of coarse particles having a particle diameter that is at least twice the volume-average particle diameter is no more than 180 out of 1 million microparticles.

Description

ビニル重合体微粒子、その製造方法、樹脂組成物および光学用材料Vinyl polymer fine particles, process for producing the same, resin composition and optical material
　本発明は、粗大粒子の低減されたビニル重合体微粒子に関し、詳細には、懸濁重合法の改良によって平均粒径の２倍以上の粒子数が極度に低減されたビニル重合体微粒子、その製造方法、上記ビニル重合体微粒子を含む樹脂組成物および光学用材料に関するものである。 The present invention relates to vinyl polymer fine particles with reduced coarse particles, and in particular, vinyl polymer fine particles in which the number of particles more than twice the average particle size is extremely reduced by improving the suspension polymerization method, and the production thereof The present invention relates to a method, a resin composition containing the vinyl polymer fine particles, and an optical material.
　重合体粒子は種々の用途に使用されている。特に微粒子材料は、フィルムや成形加工品等のプラスチック製品、あるいは、塗料、インキ、接着剤等の液状製品に添加され、物性面の強化、製品の高機能化、高性能化をもたらしている。近年は、液晶表示装置等の光学用途に適用するため、粒子径や機能を高度に制御した微粒子が必要とされている。 Polymer particles are used for various purposes. In particular, fine particle materials are added to plastic products such as films and molded products, or liquid products such as paints, inks, adhesives, and the like, resulting in enhanced physical properties, higher functionality and higher performance of the products. In recent years, in order to be applied to optical applications such as liquid crystal display devices, fine particles with highly controlled particle diameter and function are required.
　このため、例えば、他の材料（樹脂やその他の添加物）との親和性の向上、微粒子自体の機械的特性および光学特性の向上等について、様々な検討が重ねられている。また、これらの光学フィルムに用いられる微粒子に対しては、特に、粗大な粒子の含有量が少ないことが望まれている。粗大な粒子は、フィルム表面に傷を発生させたり、光拡散性能を低下させるためである。しかも、平均粒子径の２倍程度といった、大きさが平均粒子径に近い粗大粒子であっても除去する必要性が高まっている。 For this reason, for example, various studies have been made on improving the affinity with other materials (resin and other additives) and improving the mechanical and optical properties of the fine particles themselves. In addition, the fine particles used in these optical films are particularly desired to have a small content of coarse particles. This is because coarse particles cause scratches on the film surface or reduce light diffusion performance. Moreover, the necessity of removing even coarse particles having a size close to the average particle size, such as about twice the average particle size, is increasing.
　このようなことから粗大粒子を低減する検討がなされており、特許文献１には、シード重合により得られた重合体粒子の分散液から、湿式分級を行った後、乾式分級することで、平均粒子径の２倍以上の大きさの粗大粒子を低減する技術が開示されている。 From this, studies to reduce coarse particles have been made, and Patent Document 1 discloses that the average particle size is obtained by performing wet classification from a dispersion of polymer particles obtained by seed polymerization, followed by dry classification. A technique for reducing coarse particles having a size of twice or more the particle diameter is disclosed.
　また、光拡散用途、特に光拡散フィルムにおいては、粗大粒子は光学的欠陥となるため所定値以下とする必要があるが、粒度分布は比較的広い方が光拡散性に優れているため、添加する微粒子としては、粒度分布が比較的広い粒子が要求されている。 In addition, in light diffusing applications, particularly in light diffusing films, coarse particles are optical defects, so it is necessary to keep them below a predetermined value. As the fine particles, particles having a relatively wide particle size distribution are required.
　ところが、シード重合法により得られる重合体粒子は、粒度分布がシャープであるため、上記要求には応え難い。 However, the polymer particles obtained by the seed polymerization method have a sharp particle size distribution and are difficult to meet the above requirements.
　また、従来の懸濁重合法により得られるビニル重合体微粒子は比較的広い粒度分布を有するため、分級することで所定の粗大粒子を除去すれば、上記要求を満足することができると考えられる。しかしながら、ビニル重合体微粒子は、通常疎水性が高く、帯電しやすいため凝集も起こりやすい。しかも、微粒子の平均径が微細に、特に平均粒子径が３．５μｍ以下といった微細な微粒子が対象となると、乾式分級によって所定の大きさの粗大粒子のみが低減された微粒子を得ることは困難である。すなわち、平均粒子径の２倍以上の粗大粒子を所定値以下に低減しようとすると、粒度分布もシャープになってしまい、上記要求を満足することができないという問題があった。 Further, since the vinyl polymer fine particles obtained by the conventional suspension polymerization method have a relatively wide particle size distribution, it is considered that the above-mentioned requirement can be satisfied if predetermined coarse particles are removed by classification. However, since the vinyl polymer fine particles are usually highly hydrophobic and easily charged, aggregation is likely to occur. Moreover, when fine particles having a fine average particle diameter, particularly an average particle diameter of 3.5 μm or less, are targeted, it is difficult to obtain fine particles in which only coarse particles of a predetermined size are reduced by dry classification. is there. That is, when trying to reduce coarse particles having an average particle size of twice or more the average particle size to a predetermined value or less, the particle size distribution becomes sharp and the above requirement cannot be satisfied.
　また、粗大粒子除去をフィルターを用いた湿式分級で行う場合に、対象粒子の平均粒子径が微細に、特に対象粒子の平均粒子径が３．５μｍ以下と微細になると、湿式分級に使うフィルターとして、粒子径の揃った液晶スペーサのために用いられるような高価なフィルターを用いざるを得ず、しかも、粒度分布の広い粒子を湿式分級した場合は、フィルターが目詰まりを起こしやすいため、広い粒度分布を有しながら粗大粒子が所定値以下に低減された微細な微粒子を製造することは困難であった。 In addition, when removing coarse particles by wet classification using a filter, if the average particle diameter of the target particles is fine, especially if the average particle diameter of the target particles is 3.5 μm or less, the filter is used for wet classification. In addition, expensive filters such as those used for liquid crystal spacers with uniform particle diameters must be used, and when particles with a wide particle size distribution are wet-classified, the filters are likely to be clogged. It was difficult to produce fine fine particles in which coarse particles were reduced to a predetermined value or less while having a distribution.
　また、フィルム用添加剤としての微粒子は、年々使用量が増大しており、粒子径の微細化と共に、より安価であることが強く要求されており、上述したような高価なフィルターを用いることは避ける必要がある。 In addition, the amount of fine particles as an additive for film is increasing year by year, and it is strongly required to be cheaper as the particle diameter becomes finer. It is necessary to avoid it.
国際公開２００８／０２３６４８号パンフレットInternational Publication No. 2008/023648 Pamphlet
　上述のように、光拡散フィルム等の光学フィルムを始めとして、フィルム添加剤に用いることのできるビニル重合体微粒子であって、平均粒子径の２倍程度の大きさの粗大粒子が所定値以下に抑えられ、かつ、粒度分布の比較的広い粒子を得ることは容易ではなく、また得る方法も知られていなかった。 As described above, vinyl polymer fine particles that can be used for film additives including optical films such as light diffusion films, and coarse particles having a size about twice the average particle size are below a predetermined value. It is not easy to obtain particles that are suppressed and have a relatively wide particle size distribution, and a method for obtaining the particles has not been known.
　そこで本発明者は、重合後の工程における分級技術によって粗大粒子を除去するのではなく、また、微粒子製造技術として、安価であり、比較的広い粒度分布のビニル重合体微粒子を得ることのできる懸濁重合技術に着目し、懸濁重合段階において粗大粒子を高度に低減する方法に関して、鋭意検討した。 Therefore, the present inventor does not remove coarse particles by a classification technique in the post-polymerization process, and is a low-price production technique that can provide vinyl polymer fine particles that are inexpensive and have a relatively wide particle size distribution. Focusing on the turbid polymerization technique, the inventors studied diligently on a method for highly reducing coarse particles in the suspension polymerization stage.
　本発明では、上記従来技術を踏まえて、所定の粒度分布を有しながら、粗大な粒子数が低減されたフィルム用添加剤として好適なビニル重合体微粒子、およびこの微粒子の製造方法を提供しようとするものである。また、本発明は、上記微粒子を含有する樹脂組成物、この樹脂組成物から得られる光学フィルムおよび光拡散フィルムを提供しようとするものである。 In the present invention, based on the above prior art, it is intended to provide vinyl polymer fine particles suitable as an additive for film having a predetermined particle size distribution and having a reduced number of coarse particles, and a method for producing the fine particles. To do. The present invention also provides a resin composition containing the fine particles, an optical film obtained from the resin composition, and a light diffusion film.
　本発明のビニル重合体微粒子は、体積基準の粒子径の変動係数が１０％以上であり、体積平均粒子径の２倍以上の粒子径を有する粗大粒子の数が、微粒子１００万個中、１８０個以下であることを特徴とする。 The vinyl polymer fine particles of the present invention have a volume-based particle diameter variation coefficient of 10% or more, and the number of coarse particles having a particle diameter of twice or more the volume average particle diameter is 1 in 180 million fine particles. It is characterized by having no more than one.
　芳香環を有するビニル重合体の微粒子であることや、ビニル重合体中の無機質成分が２質量％以下であることは、いずれも好ましい。本発明のビニル重合体微粒子は、光学用材料用添加剤および／またはフィルム用添加剤であることが好ましい。特に、光学フィルムに添加されるものであること、あるいは、光拡散剤として用いられるものであることが好ましい。 It is preferable that the polymer is fine particles of a vinyl polymer having an aromatic ring and that the inorganic component in the vinyl polymer is 2% by mass or less. The vinyl polymer fine particles of the present invention are preferably an additive for optical materials and / or an additive for films. In particular, it is preferable to be added to an optical film or to be used as a light diffusing agent.
　本発明には上記ビニル重合体微粒子を製造する方法も含まれ、この方法は、水、モノマー成分およびラジカル重合開始剤を含む混合液を、懸濁装置に導入して懸濁させ液滴を形成する液滴形成工程と、重合工程とを含み、前記液滴形成工程は少なくとも段階（１）と段階（２）とからなり、段階（１）における剪断力よりも段階（２）における剪断力を大きくすることを特徴とする。 The present invention also includes a method for producing the above-mentioned vinyl polymer fine particles. In this method, a liquid mixture containing water, a monomer component and a radical polymerization initiator is introduced into a suspension apparatus and suspended to form droplets. A droplet forming step and a polymerization step, wherein the droplet forming step comprises at least step (1) and step (2), and the shear force in step (2) is set higher than the shear force in step (1). It is characterized by being enlarged.
　上記懸濁装置はパイプラインミキサーであることが好ましい。また、懸濁装置に導入する混合液の総量をＶ（ｋｇ）、懸濁装置からの吐出量をｖ（ｍ3／ｈｒ）とするときに、段階（１）におけるｖ／Ｖよりも段階（２）におけるｖ／Ｖを大きくする態様、段階（１）におけるｖ／Ｖを、０．０１ｍ3／（ｈｒ・ｋｇ）以上、０．１０ｍ3／（ｈｒ・ｋｇ）以下とする態様は、いずれも本発明法の好ましい実施態様である。 The suspension device is preferably a pipeline mixer. Further, when the total amount of the liquid mixture introduced into the suspension device is V (kg) and the discharge amount from the suspension device is v (m 3 / hr), the step (1) is more than the v / V step (1). aspect of increasing v / V to in 2), v / V to in step (1), 0.01m 3 / ( hr · kg) or more, manner to 0.10m 3 / (hr · kg) or less, one Is also a preferred embodiment of the process of the invention.
　本発明には、上記ビニル重合体微粒子を含む樹脂組成物、上記ビニル重合体微粒子を含む光学用材料、上記ビニル重合体微粒子を含むフィルム、および上記ビニル重合体微粒子を含む光学フィルムが含まれる。 The present invention includes a resin composition containing the vinyl polymer fine particles, an optical material containing the vinyl polymer fine particles, a film containing the vinyl polymer fine particles, and an optical film containing the vinyl polymer fine particles.
　また、本発明には、基材フィルムの少なくとも片面に、上記樹脂組成物を含む塗布液を塗工して得られる光学フィルム、特に、光拡散フィルムが包含される。 Further, the present invention includes an optical film obtained by applying a coating solution containing the resin composition on at least one surface of the base film, particularly a light diffusion film.
　本発明のビニル重合体微粒子は、比較的広い粒度分布を有するにもかかわらず、粗大粒子数が低減されたものであるので、フィルム表面に傷を発生させたりすることがなく、光拡散剤として使用したときに、優れた光拡散性を示す。さらに、本発明のビニル重合体微粒子の製造方法は、懸濁液を作製する際に、懸濁装置における剪断力の掛け方を１段階目と２段階目とで変える、という簡単な方法で、重合段階で粗大粒子数を低減することができるため、工業的に極めて有用な方法である。 Since the vinyl polymer fine particles of the present invention have a relatively wide particle size distribution and a reduced number of coarse particles, they do not cause scratches on the film surface, and as a light diffusing agent. Excellent light diffusivity when used. Furthermore, the production method of the vinyl polymer fine particles of the present invention is a simple method in which the method of applying the shearing force in the suspension device is changed between the first stage and the second stage when the suspension is prepared. Since the number of coarse particles can be reduced in the polymerization stage, this is an industrially extremely useful method.
　［ビニル重合体微粒子］
　本発明のビニル重合体微粒子は、１個１個のビニル重合体微粒子が多数集まった微粒子集合体のことを意味する。そして、本発明のビニル重合体微粒子は、体積基準の粒子径の変動係数が１０％以上であり、かつ、体積平均粒子径の２倍以上の粒子径を有する粗大粒子数が、ビニル重合体微粒子１００万個中、１８０個以下であるところに特徴がある。例えば、体積平均粒子径が３．０μｍのビニル重合体微粒子を得ようとする場合、体積平均粒子径が６μｍ以上の粒子が粗大粒子となるが、このような微細なレベルで分級可能なフィルターは、エレクトロフォーミングで形成された非常に高価なエレクトロフォームしか現存しない。液晶セルのスペーサー分野ではこのような高価なエレクトロフォームが利用されているが、粒度分布の広い粒子を原料とした場合、目詰まり等が起こることによって、粒子径の変動係数を維持したまま粗大粒子のみを除去することは困難である。粒度分布が適度に広い粒子が要求される光学シート分野で使用するために、工業的レベルで分級する場合は、このような高価なフィルターを採用することはできない。粗大粒子数は、ビニル重合体微粒子１００万個中、１７０個以下が好ましく、１６０個以下がより好ましく、１５０個以下がさらに好ましい。 [Vinyl polymer fine particles]
The vinyl polymer fine particles of the present invention mean a fine particle aggregate in which many vinyl polymer fine particles are collected one by one. The vinyl polymer fine particles of the present invention have a volume-based particle diameter variation coefficient of 10% or more, and the number of coarse particles having a particle diameter of twice or more the volume average particle diameter is vinyl polymer fine particles. It is characterized in that it is 180 or less out of 1 million. For example, when vinyl polymer fine particles having a volume average particle diameter of 3.0 μm are to be obtained, particles having a volume average particle diameter of 6 μm or more become coarse particles. A filter that can be classified at such a fine level is Only very expensive electroforms formed by electroforming currently exist. In the spacer field of liquid crystal cells, such expensive electroforms are used, but when particles with a wide particle size distribution are used as raw materials, clogging and the like cause coarse particles while maintaining the coefficient of variation in particle diameter. It is difficult to remove only. In order to use in the optical sheet field where particles having a moderately wide particle size distribution are required, such an expensive filter cannot be employed when classifying at an industrial level. The number of coarse particles is preferably 170 or less, more preferably 160 or less, and even more preferably 150 or less, out of 1 million vinyl polymer fine particles.
　ここで、粗大粒子数のカウント方法について説明する。カウント方法は特に限定されないが、簡便な方法として、フロー式粒子像解析装置を用いる方法が好ましい。本発明では、シスメックス社製のフロー式粒子像解析装置「ＦＰＩＡ（登録商標）－３０００」を用いた。まず、粒子２５万個を測定対象として個数基準の粒度分布データを得て、得られた粒度分布データを元に、所定の粒径以上の粒子（粗大粒子）全ての形状を画像で確認し、円形度が０．９７以上の粒子の個数を粗大粒子数とした。この測定を４回繰り返せば、１００万個当たりの粗大粒子数が分かる。円形度が０．９７より小さいものは、所定の粒径以上であっても粗大粒子とはしない。後述する解砕の際にほぐれなかった（凝集がほぐれなかった）凝集粒子だからである。 Here, the method for counting the number of coarse particles will be described. The counting method is not particularly limited, but as a simple method, a method using a flow type particle image analyzer is preferable. In the present invention, a flow type particle image analyzer “FPIA (registered trademark) -3000” manufactured by Sysmex Corporation was used. First, obtain the number-based particle size distribution data for 250,000 particles as the measurement object, and based on the obtained particle size distribution data, check the shape of all particles (coarse particles) of a predetermined particle size or larger with an image, The number of particles having a circularity of 0.97 or more was defined as the number of coarse particles. If this measurement is repeated four times, the number of coarse particles per million can be found. Particles having a circularity smaller than 0.97 are not considered as coarse particles even if they have a predetermined particle size or more. This is because they are aggregated particles that have not been loosened (not agglomerated) during the crushing described later.
　体積平均粒子径は、体積基準の平均粒子径であり、コールター原理を使用した精密粒度分布測定装置により測定することができる。例えば、ベックマンコールター社製「コールターマルチサイザーIII型」等により測定することが好ましい。なお、本発明のビニル重合体微粒子の体積平均粒子径は、１０μｍ以下が好ましく、３．５μｍ以下がより好ましく、３．３μｍ以下がさらに好ましい。体積平均粒子径の下限は特に限定されないが、製造限界を考慮すると０．５μｍであり、１．０μｍが好ましく、２．０μｍがより好ましく、２．５μｍがさらに好ましい。 The volume average particle diameter is a volume-based average particle diameter, and can be measured by a precision particle size distribution measuring apparatus using the Coulter principle. For example, it is preferable to measure using “Coulter Multisizer III type” manufactured by Beckman Coulter. The volume average particle diameter of the vinyl polymer fine particles of the present invention is preferably 10 μm or less, more preferably 3.5 μm or less, and even more preferably 3.3 μm or less. The lower limit of the volume average particle diameter is not particularly limited, but considering the production limit, it is 0.5 μm, preferably 1.0 μm, more preferably 2.0 μm, and further preferably 2.5 μm.
　体積基準の粒子径の変動係数は、コールター原理を使用した精密粒度分布測定装置により測定することができ、ベックマンコールター社製「コールターマルチサイザーIII型」により測定することが好ましい。 The coefficient of variation of the volume-based particle diameter can be measured with a precision particle size distribution measuring apparatus using the Coulter principle, and is preferably measured with “Coulter Multisizer Type III” manufactured by Beckman Coulter.
　本発明のビニル重合体微粒子の体積基準の粒子径の変動係数（ＣＶ値）は、１０％以上である。光拡散剤として用いた場合に光拡散性に優れるためである。同様の理由から、２０％以上が好ましく、より好ましくは２５％以上であり、特に好ましくは３０％以上である。一方、粒子径の変動係数の上限値は特に限定されないが、変動係数が大きすぎても光拡散性が低下する場合があるため、５０％以下が好ましく、より好ましくは４０％以下である。 The variation coefficient (CV value) of the volume-based particle diameter of the vinyl polymer fine particles of the present invention is 10% or more. This is because when used as a light diffusing agent, it has excellent light diffusibility. For the same reason, 20% or more is preferable, more preferably 25% or more, and particularly preferably 30% or more. On the other hand, the upper limit value of the coefficient of variation of the particle diameter is not particularly limited. However, since the light diffusibility may be lowered even if the coefficient of variation is too large, it is preferably 50% or less, more preferably 40% or less.
　本発明のビニル重合体微粒子においては、最大粒子径が体積平均粒子径の１０倍以下の大きさであることが好ましい。より好ましくは５倍以下であり、さらに好ましくは４倍以下である。最大粒子径は、上記の粗大粒子数の測定方法において、４回の測定により検出された、円形度が０．９７以上の粒子の粗大粒子の粒子径の中で最も大きい粒子径である。 In the vinyl polymer fine particles of the present invention, the maximum particle size is preferably 10 times or less than the volume average particle size. More preferably, it is 5 times or less, More preferably, it is 4 times or less. The maximum particle size is the largest particle size among the coarse particle sizes of particles having a circularity of 0.97 or more, which are detected by four measurements in the method for measuring the number of coarse particles.
　［ビニル重合体微粒子の組成］
　次に、本発明のビニル重合体微粒子の組成について説明する。　　　
　本発明のビニル重合体微粒子を合成する際に用いられるモノマー成分には、芳香環を有するビニル系モノマーが含まれていることが好ましい。このようなモノマーを用いると、得られるビニル重合体微粒子が芳香環を有するものとなり、帯電し易い微粒子となる。平均粒子径が１０μｍ以下（特に３．５μｍ以下）で粒子径の変動係数が１０％以上であり、しかも帯電し易い微粒子の場合、乾式分級では、装置内への付着による配管の閉塞の発生が起こり、作業が停止するため、粗大粒子のみを除去することは容易ではない。湿式分級においては前述したとおりである。一方、本発明の製造方法では帯電のし易さには関係なく粗大粒子が低減されたビニル重合体微粒子が得られるため、帯電し易い組成の微粒子の場合、本発明の微粒子、製造方法の有用性がより一層高いものとなる。よって、本発明のビニル重合体微粒子は芳香環を有していることが好ましいのである。また、芳香環を有するビニル重合体微粒子は屈折率が高いため、光拡散剤としての有用性が増す。なお、本発明では、後述するようにラジカル重合で微粒子を製造するので、用い得るモノマーは、ラジカル重合性である。 [Composition of vinyl polymer fine particles]
Next, the composition of the vinyl polymer fine particles of the present invention will be described.
The monomer component used in synthesizing the vinyl polymer fine particles of the present invention preferably contains a vinyl monomer having an aromatic ring. When such a monomer is used, the resulting vinyl polymer fine particles have an aromatic ring and become finely charged fine particles. In the case of fine particles that have an average particle size of 10 μm or less (particularly 3.5 μm or less) and a particle size variation coefficient of 10% or more and are easily charged, the dry classification may cause clogging of pipes due to adhesion in the apparatus. It happens and the work stops, so it is not easy to remove only the coarse particles. The wet classification is as described above. On the other hand, in the production method of the present invention, vinyl polymer fine particles with reduced coarse particles can be obtained regardless of the ease of charging. Therefore, in the case of fine particles having an easily charged composition, the fine particles of the present invention and the production method are useful. The property becomes even higher. Therefore, it is preferable that the vinyl polymer fine particles of the present invention have an aromatic ring. Moreover, since the vinyl polymer fine particles having an aromatic ring have a high refractive index, their usefulness as a light diffusing agent increases. In the present invention, since the fine particles are produced by radical polymerization as will be described later, the monomer that can be used is radically polymerizable.
　芳香環を有するビニル系モノマーとしては、スチレン、ｏ－メチルスチレン、ｍ－メチルスチレン、ｐ－メチルスチレン、α－メチルスチレン、ｐ－メトキシスチレン、ｐ－ｔｅｒｔ－ブチルスチレン、ｐ－フェニルスチレン、ｏ－クロロスチレン、ｍ－クロロスチレン、ｐ－クロロスチレン、ｏ－エチルビニルベンゼン、ｍ－エチルビニルベンゼン、ｐ－エチルビニルベンゼン等の単官能スチレン系モノマー；ジビニルベンゼン、ジビニルナフタレン、およびこれらの誘導体等の芳香族ジビニル化合物が挙げられ、単独で、または複数種を組み合わせて用いることができる。 Examples of the vinyl monomer having an aromatic ring include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-tert-butylstyrene, p-phenylstyrene, o Monofunctional styrene monomers such as chlorostyrene, m-chlorostyrene, p-chlorostyrene, o-ethylvinylbenzene, m-ethylvinylbenzene, p-ethylvinylbenzene; divinylbenzene, divinylnaphthalene, and derivatives thereof The aromatic divinyl compound can be used, and can be used alone or in combination of two or more.
　また、上記芳香環を有するモノマーに変えて、または加えて、（メタ）アクリル系モノマーを用いることもできる。（メタ）アクリル系モノマーとしては、例えば、アクリル酸、アクリル酸メチル、アクリル酸エチル、アクリル酸ｎ－ブチル、アクリル酸イソブチル、アクリル酸ドデシル、アクリル酸ステアリル、アクリル酸２－エチルヘキシル、アクリル酸テトラヒドロフルフリル、メタクリル酸、メタクリル酸メチル、メタクリル酸エチル、メタクリル酸プロピル、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ｎ－オクチル、メタクリル酸ドデシル、メタクリル酸２－エチルヘキシル、メタクリル酸ステアリル等の単官能（メタ）アクリル系モノマーが挙げられるが、これらに限定されるものではない。これらの単官能（メタ）アクリル系モノマーは１種を単独で用いてもよく、複数種を組合せて用いてもよい。 Further, a (meth) acrylic monomer can be used instead of or in addition to the monomer having an aromatic ring. Examples of the (meth) acrylic monomer include acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, stearyl acrylate, 2-ethylhexyl acrylate, and tetrahydrofluorate acrylate. Monofunctional such as furyl, methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate Although (meth) acrylic-type monomer is mentioned, it is not limited to these. These monofunctional (meth) acrylic monomers may be used alone or in combination of two or more.
　分子中に複数の重合性二重結合基を有する架橋性ビニル系モノマーを使用することも好ましい。架橋性ビニル系モノマーとしては、上述した芳香族ジビニル化合物および架橋性（メタ）アクリル系モノマーが好ましい。かかる単量体成分を用いることで、分子間に架橋構造を有するビニル重合体微粒子が得られる。架橋性（メタ）アクリル系モノマーとしては、トリアクリル酸トリメチロールプロパン、ジメタクリル酸エチレングリコール、ジメタクリル酸ジエチレングリコール、ジメタクリル酸トリエチレングリコール、ジメタクリル酸デカエチレングリコール、ジメタクリル酸ペンタデカエチレングリコール、ジメタクリル酸ペンタコンタヘクタエチレングリコール、ジメタクリル酸１，３－ブチレン、メタクリル酸アリル、トリメタクリル酸トリメチロールプロパン、テトラメタクリル酸ペンタエリスリトール、ジメタクリル酸フタル酸ジエチレングリコール等の（メタ）アクリル系モノマーが挙げられ、単独で、または複数種を組み合わせて用いることができる。 It is also preferable to use a crosslinkable vinyl monomer having a plurality of polymerizable double bond groups in the molecule. As the crosslinkable vinyl monomer, the aromatic divinyl compound and the crosslinkable (meth) acrylic monomer described above are preferable. By using such a monomer component, vinyl polymer fine particles having a crosslinked structure between molecules can be obtained. Crosslinkable (meth) acrylic monomers include trimethylolpropane triacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, decaethylene glycol dimethacrylate, pentadecaethylene glycol dimethacrylate (Meth) acrylic monomers such as ethylene glycol dimethacrylate pentaethylene glycol, 1,3-butylene dimethacrylate, allyl methacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, diethylene glycol dimethacrylate And may be used alone or in combination.
　さらに、Ｎ，Ｎ－ジビニルアニリン、ジビニルエーテル、ジビニルサルファイド、ジビニルスルホン酸等の架橋剤、ポリブタジエンおよび特公昭５７－５６５０７号公報、特開昭５９－２２１３０４号公報、特開昭５９－２２１３０５号公報、特開昭５９－２２１３０６号公報、特開昭５９－２２１３０７号公報等に記載される反応性重合体等を使用してもよい。 Further, crosslinking agents such as N, N-divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfonic acid and the like, polybutadiene, and JP-B-57-56507, JP-A-59-221304, JP-A-59-221305 The reactive polymers described in JP-A-59-221306 and JP-A-59-221307 may be used.
　本発明で好ましいビニル重合体微粒子としては、スチレン系単官能モノマーと架橋性（メタ）アクリル系モノマーとを含むモノマー成分を共重合して得られるビニル重合体微粒子（態様(i)）、または、単官能（メタ）アクリル系モノマーと芳香族ジビニル化合物とを含むモノマー成分を共重合して得られるビニル重合体微粒子（態様(ii)）である。 As vinyl polymer fine particles preferable in the present invention, vinyl polymer fine particles (embodiment (i)) obtained by copolymerizing a monomer component containing a styrene monofunctional monomer and a crosslinkable (meth) acrylic monomer, or It is a vinyl polymer fine particle (embodiment (ii)) obtained by copolymerizing a monomer component containing a monofunctional (meth) acrylic monomer and an aromatic divinyl compound.
　態様(i)の場合、スチレン系単官能モノマーは１０～７０質量％、架橋性(メタ)アクリル系モノマーは０～６０質量％、その他のモノマーは０～４０質量％とすることが好ましい。この態様(i)においては、スチレン系単官能モノマーとしてはスチレンが好ましく、架橋性(メタ)アクリル系モノマーとしては、トリメタクリル酸トリメチロールプロパンや、ジメタクリル酸エチレングリコールが好ましい。 In the case of the embodiment (i), the styrene monofunctional monomer is preferably 10 to 70% by mass, the crosslinkable (meth) acrylic monomer is 0 to 60% by mass, and the other monomers are preferably 0 to 40% by mass. In this embodiment (i), styrene is preferred as the styrene monofunctional monomer, and trimethylolpropane trimethacrylate and ethylene glycol dimethacrylate are preferred as the crosslinkable (meth) acrylic monomer.
　一方、態様(ii)の場合、単官能（メタ）アクリル系モノマーは０～６０質量％、芳香族ジビニル化合物は１０～７０質量％、その他のモノマーは０～４０質量％とすることが好ましい。単官能（メタ）アクリル系モノマーとしてはメタクリル酸メチルが好ましく、芳香族ジビニル化合物としてはジビニルベンゼンが好ましい。 On the other hand, in the case of the embodiment (ii), it is preferable that the monofunctional (meth) acrylic monomer is 0 to 60% by mass, the aromatic divinyl compound is 10 to 70% by mass, and the other monomers are 0 to 40% by mass. The monofunctional (meth) acrylic monomer is preferably methyl methacrylate, and the aromatic divinyl compound is preferably divinylbenzene.
　本発明のビニル重合体微粒子としては態様(i)が好ましく、中でも、スチレンと架橋性（メタ）アクリル系モノマーとを含むモノマー成分を共重合して得られるものがより好ましい。 Embodiment (i) is preferable as the vinyl polymer fine particles of the present invention, and among them, those obtained by copolymerizing a monomer component containing styrene and a crosslinkable (meth) acrylic monomer are more preferable.
　また、本発明のビニル重合体微粒子は、無機質成分を含まないか、含んでも２質量％以下であることが好ましい。例えば、本発明のビニル重合体微粒子を製造する際に、モノマー成分中にシリコーン骨格を有する、あるいはシリコーン骨格を形成し得る化合物やモノマーが存在すると、懸濁重合において、懸濁装置を用いて液滴形成を行うときに液滴の微細化が進まず、得られるビニル重合体微粒子中の粗大粒子が増大するおそれがある。なお、無機質成分量は、粒子を空気等の酸化性雰囲気中で室温から昇温し、８００℃で１時間加熱処理した後の灰分の質量とする。 Further, it is preferable that the vinyl polymer fine particles of the present invention contain no inorganic component or contain 2% by mass or less. For example, when the vinyl polymer fine particles of the present invention are produced, if a monomer or a compound or monomer having a silicone skeleton or capable of forming a silicone skeleton is present in the monomer component, the suspension polymer is used in suspension polymerization. When droplets are formed, the size of the droplets does not advance and coarse particles in the resulting vinyl polymer fine particles may increase. The amount of the inorganic component is the mass of ash after the particles are heated from room temperature in an oxidizing atmosphere such as air and heated at 800 ° C. for 1 hour.
　また、本発明のビニル重合体微粒子は、懸濁重合法により得られる微粒子であることが好ましい。シード重合法や分散重合に比べて安価であり光学フィルム用の微粒子として経済的に有利であるとともに、粒子径の変動係数を１０％以上に制御し易いためである。 The vinyl polymer fine particles of the present invention are preferably fine particles obtained by a suspension polymerization method. This is because it is cheaper than seed polymerization and dispersion polymerization, is economically advantageous as fine particles for optical films, and can easily control the coefficient of variation of particle diameter to 10% or more.
　［ビニル重合体微粒子の製造方法］
　次に、本発明のビニル重合体微粒子の製造方法について説明する。本発明では、上述した理由により懸濁重合法の採用が好ましい。懸濁重合とは、一般的には、モノマー成分を、水等に分散、懸濁させることにより得られた液滴状のモノマー成分を重合することにより、重合体微粒子が水中に分散含有されてなる分散液を得る方法である。この懸濁重合では、液滴形成時に最終的に得られる重合体微粒子の大きさが決定してしまう。本発明者は、液滴形成時の懸濁方法を改良することで粗大粒子の低減を図り、本発明を完成させた。 [Method for producing vinyl polymer fine particles]
Next, a method for producing the vinyl polymer fine particles of the present invention will be described. In the present invention, it is preferable to employ the suspension polymerization method for the reasons described above. In suspension polymerization, generally, polymer particles are dispersed and contained in water by polymerizing droplet-like monomer components obtained by dispersing and suspending monomer components in water or the like. Is obtained. In this suspension polymerization, the size of the polymer fine particles finally obtained at the time of droplet formation is determined. The present inventor completed the present invention by reducing the coarse particles by improving the suspension method during droplet formation.
　すなわち、本発明の製造方法は、水、モノマー成分およびラジカル重合開始剤を含む混合液を、懸濁装置に導入して懸濁させ液滴を形成する液滴形成工程と重合工程とを含み、前記液滴形成工程は、少なくとも段階（１）と段階（２）とからなり、段階（１）における剪断力よりも段階（２）における剪断力を大きくすることを特徴とする。 That is, the production method of the present invention includes a droplet formation step and a polymerization step in which a mixed solution containing water, a monomer component and a radical polymerization initiator is introduced into a suspension device and suspended to form droplets, The droplet forming process includes at least a stage (1) and a stage (2), and the shear force in the stage (2) is larger than the shear force in the stage (1).
　本発明では、モノマー成分、ラジカル重合開始剤および水を含む混合液を強制撹拌して懸濁し、液滴を製造する際の懸濁方法は、特に限定されない。例えば、混合物全量を攪拌等で直接懸濁する方法、混合液を含有する容器と該容器に連結した循環ラインの途中に備えた懸濁装置（外部懸濁装置ともいう）に混合液を供給して懸濁する方法が挙げられる。懸濁効率の観点から後者の方法が好ましい。後者の方法は、より具体的には、反応容器に連結した循環ラインの途中に懸濁装置を設置した装置を用い、上記混合液を反応容器から懸濁装置へと導入し、剪断力を与えて撹拌した後、懸濁装置から再び反応容器に戻す、という操作を繰り返す方法である。このとき、液滴を製造する工程を少なくとも２段階に分け、段階（１）における剪断力よりも、段階（２）における剪断力を大きくすることが重要である。剪断力は、懸濁装置における懸濁条件、例えば、外部懸濁装置の吐出量や攪拌回転数を段階（１）と（２）で変えることによって、制御可能である。 In the present invention, the suspension method for producing droplets by forcibly stirring and suspending a mixed solution containing a monomer component, a radical polymerization initiator and water is not particularly limited. For example, a method of directly suspending the entire amount of the mixture by stirring or the like, supplying a mixed solution to a container containing the mixed solution and a suspension device (also referred to as an external suspension device) provided in the middle of a circulation line connected to the container. And suspension method. The latter method is preferred from the viewpoint of suspension efficiency. More specifically, the latter method uses a device in which a suspension device is installed in the middle of a circulation line connected to the reaction vessel, and introduces the above mixed solution from the reaction vessel to the suspension device to give a shearing force. After stirring, the operation of returning the suspension device back to the reaction vessel is repeated. At this time, it is important to divide the process for producing droplets into at least two stages and to increase the shear force in the stage (2) rather than the shear force in the stage (1). The shearing force can be controlled by changing the suspension conditions in the suspension device, for example, the discharge amount of the external suspension device and the stirring rotation speed in steps (1) and (2).
　剪断力を吐出量で制御する場合、懸濁装置に導入する混合液（懸濁後に重合に供される反応液）総量をＶ（ｋｇ）、懸濁装置からの吐出量をｖ（ｍ3／ｈｒ）とするときに、段階（１）におけるｖ／Ｖよりも、段階（２）におけるｖ／Ｖを大きくしてやればよい。段階（１）では、段階（２）よりも低い吐出量で懸濁を行い、段階（２）では段階（１）よりも高い吐出量で懸濁を行うということである。また、攪拌回転数で制御する場合は、段階（１）における回転数よりも、段階（２）における回転数を大きくしてやればよい。言い換えれば、段階（１）は段階（２）よりも低速回転で液滴形成を行い、段階（２）は段階（１）よりも高速回転で液滴形成を行う。 When the shearing force is controlled by the discharge amount, the total amount of the mixed solution (reaction solution used for polymerization after suspension) introduced into the suspension device is V (kg), and the discharge amount from the suspension device is v (m 3 / hr), v / V in step (2) may be made larger than v / V in step (1). In step (1), suspension is performed at a lower discharge rate than in step (2), and in step (2) suspension is performed at a higher discharge amount than in step (1). Moreover, when controlling by stirring rotation speed, what is necessary is just to make the rotation speed in a stage (2) larger than the rotation speed in a stage (1). In other words, in step (1), droplets are formed at a lower speed than in step (2), and in step (2), droplets are formed at a higher speed than in step (1).
　本発明者は、低速回転のみで循環させるだけでは粗大粒子の低減に長時間かかってしまうこと、すなわち、循環を多数回繰り返さなければならないこと、一方で、高吐出量（高速回転）を行うと、体積平均粒子径自体は小さくなるが粗大粒子は低減されないこと、等を見出し、その後も検討を続けた結果、低速回転で循環を繰り返した後に、高速回転へと切り替えると、効果的に粗大粒子を低減できることを見出して上記構成を採用したのである。 When the present inventor simply circulates only at a low speed, it takes a long time to reduce coarse particles, that is, the circulation must be repeated many times. On the other hand, when a high discharge amount (high speed rotation) is performed. As a result of finding out that the volume average particle size itself is small but the coarse particles are not reduced, etc., and as a result of continuing investigations, after repeating the circulation at low speed rotation, switching to high speed rotation effectively produces coarse particles. It was found that the above-mentioned configuration can be reduced, and the above configuration was adopted.
　外部懸濁装置としては、特に限定されないが、パイプラインミキサーまたはエバラマイルダーが好ましい。より好ましくはパイプラインミキサーである。なお、本発明のパイプラインミキサーには、パイプラインミキサー、パイプラインホモミキサーのいずれも包含される。 The external suspension device is not particularly limited, but a pipeline mixer or an ebara milder is preferable. A pipeline mixer is more preferable. The pipeline mixer of the present invention includes both pipeline mixers and pipeline homomixers.
　懸濁装置としてパイプラインミキサーを用いる場合、液滴形成工程は次のように行われる。反応容器に連結した循環ラインの途中にパイプラインミキサーを設置した装置を用い、上記混合物を反応容器からパイプラインミキサーへと導入し、剪断力を与えて撹拌した後、パイプラインミキサーから再び反応容器に戻す、という操作を連続して繰り返す。このとき、液滴を製造する工程を２段階に分ける。そして、懸濁装置に導入される混合液（懸濁後に重合に供される反応液）総量をＶ（ｋｇ）、パイプラインミキサーの吐出量をｖ（ｍ3／ｈｒ）とするときに、段階（１）におけるｖ／Ｖよりも、段階（２）におけるｖ／Ｖを大きくする。吐出量の代りに、パイプラインミキサーの攪拌回転数を指標にして同様に行ってもよい。 When a pipeline mixer is used as the suspension device, the droplet forming process is performed as follows. Using a device in which a pipeline mixer is installed in the middle of the circulation line connected to the reaction vessel, the mixture is introduced from the reaction vessel into the pipeline mixer, stirred by applying a shearing force, and then again from the pipeline mixer to the reaction vessel. The operation of returning to is continuously repeated. At this time, the process of manufacturing the droplet is divided into two stages. When the total amount of the mixed liquid (reaction liquid used for polymerization after suspension) introduced into the suspension device is V (kg) and the discharge amount of the pipeline mixer is v (m 3 / hr), V / V in step (2) is made larger than v / V in (1). Instead of the discharge amount, the same may be performed using the stirring rotation speed of the pipeline mixer as an index.
　液滴形成工程における段階（１）のｖ／Ｖは０．０１ｍ3／（ｈｒ・ｋｇ）以上が好ましく、０．１０ｍ3／（ｈｒ・ｋｇ）以下であることが好ましい。より好ましくは０．０２ｍ3／（ｈｒ・ｋｇ）以上であり、０．０５ｍ3／（ｈｒ・ｋｇ）以下である。段階（２）のｖ／Ｖは０．０５ｍ3／（ｈｒ・ｋｇ）以上が好ましく、０．１５ｍ3／（ｈｒ・ｋｇ）以下であることが好ましい。また、段階（１）のｖ／Ｖに対する段階（２）のｖ／Ｖの大きさの比は、１．０１倍以上が好ましく、１．５倍以下が好ましい。より好ましくは１．０５倍以上であり、１．２倍以下である。この比が１．０１倍未満では、液滴形成を２段階で行う効果が小さくなる虞があり、１．５倍を超えると、特に平均粒子径が大きめの場合、粗大粒子量が所定値以下であるが、比較的多いものとなる虞がある。つまり、平均粒子径が小さくなり過ぎないように制御するためにパス回数を少なくすると粗大粒子量が比較的多くなり、一方、パス回数を増やすと平均粒子径が小さくなりすぎる場合がある。 V / V is preferably 0.01m 3 / (hr · kg) or more stages (1) of the droplet formation process is preferably 0.10m 3 / (hr · kg) or less. More preferably 0.02m 3 / (hr · kg) or more, 0.05m 3 / (hr · kg) or less. V / V is preferably 0.05m 3 / (hr · kg) or more stages (2), is preferably 0.15m 3 / (hr · kg) or less. Further, the ratio of the magnitude of v / V in step (2) to v / V in step (1) is preferably 1.01 or more, and more preferably 1.5 or less. More preferably, it is 1.05 times or more and 1.2 times or less. If this ratio is less than 1.01, the effect of forming droplets in two stages may be reduced, and if it exceeds 1.5, the amount of coarse particles is below a predetermined value, particularly when the average particle size is large. However, there is a risk that it will be relatively large. In other words, if the number of passes is decreased to control the average particle size so as not to be too small, the amount of coarse particles becomes relatively large. On the other hand, if the number of passes is increased, the average particle size may be too small.
　なお、上記の段階（１）および段階（２）のｖ／Ｖの好適範囲、段階（１）のｖ／Ｖに対する段階（２）のｖ／Ｖの大きさの比の好適範囲は、懸濁装置によるものではないが、パイプラインミキサーを懸濁装置として用いる場合、上記範囲で行うことが、工業規模での装置能力、コスト等の観点から有利である。吐出量の代わりに攪拌回転数を指標にする場合、段階（１）の回転数に対する段階（２）の回転数の比の好適範囲は、段階（１）のｖ／Ｖに対する段階（２）のｖ／Ｖの大きさの比の好適範囲と同様である。 The preferred range of v / V in step (1) and step (2) above, and the preferred range of the ratio of v / V magnitude in step (2) to v / V in step (1) are suspensions. Although not depending on the apparatus, when the pipeline mixer is used as a suspension apparatus, it is advantageous to carry out in the above range from the viewpoint of the apparatus capacity on an industrial scale, cost, and the like. When the stirring rotation speed is used as an index instead of the discharge amount, a preferable range of the ratio of the rotation speed of the stage (2) to the rotation speed of the stage (1) is that of the stage (2) with respect to v / V of the stage (1). This is the same as the preferable range of the ratio of v / V.
　段階（１）および（２）とも、外部懸濁装置（パイプラインミキサー等）への循環は数十回繰り返す（パス回数を数十回とする）ことが好ましい。循環の回数（パス回数ともいう）は、特に限定されないが、段階（１）においても、段階（２）においてもそれぞれ５回以上、１００回以下が好ましい。５回未満では、各段階における処理効果が不充分となる虞があり、一方、１００回を超えると生産性が低下する虞がある。より好ましくは１０回以上、６０回以下である。 In both steps (1) and (2), the circulation to the external suspension device (pipeline mixer or the like) is preferably repeated tens of times (the number of passes is set to tens of times). The number of circulations (also referred to as the number of passes) is not particularly limited, but is preferably 5 times or more and 100 times or less in both step (1) and step (2). If it is less than 5 times, the treatment effect at each stage may be insufficient. On the other hand, if it exceeds 100 times, productivity may be reduced. More preferably, it is 10 times or more and 60 times or less.
　以下、懸濁重合に用いる各成分について説明する。 Hereinafter, each component used for suspension polymerization will be described.
　［水］
　水は、懸濁重合の場を提供する媒体として用いる。安価かつ安全であり、油溶性モノマーの懸濁重合には最適である。重合熱の除去にも適している。 [water]
Water is used as a medium that provides a field for suspension polymerization. It is inexpensive and safe and is optimal for suspension polymerization of oil-soluble monomers. It is also suitable for removing polymerization heat.
　懸濁液を重合させる際には、懸濁液をそのまま加熱して重合する場合と、懸濁液にさらに水を添加してから加熱する場合があり、いずれも採用可能である。懸濁液をそのまま加熱する場合には、懸濁液１００質量部中、水は６０～８０質量部程度が好ましい。懸濁液に水を加える場合は、希釈前の懸濁液１００質量部中、水は４０～６０質量部程度が好ましく、水添加後においては、重合反応液１００質量部中、水は６０～９０質量部程度が好ましい。適切な水量、適切な濃度で懸濁液の製造を行うことで懸濁液の安定性が高まり、適切な水量、適切な濃度で懸濁重合を行うことで、重合時に反応容器に付着する成分を抑制できる等、重合の安定性が向上する。 When polymerizing the suspension, there are a case where the suspension is heated and polymerized as it is, and a case where water is further added to the suspension and then heated, both of which can be employed. When the suspension is heated as it is, water is preferably about 60 to 80 parts by mass in 100 parts by mass of the suspension. When adding water to the suspension, water is preferably about 40 to 60 parts by mass in 100 parts by mass of the suspension before dilution, and after addition of water, 60 to 60 parts of water in 100 parts by mass of the polymerization reaction solution is added. About 90 parts by mass is preferable. Ingredients that adhere to the reaction vessel during polymerization by performing suspension polymerization at an appropriate amount of water and at an appropriate concentration by producing suspension with an appropriate amount of water and at an appropriate concentration. The stability of polymerization is improved.
　また、水に加えて水溶性有機溶媒を用いてもよい。水溶性有機溶媒を、モノマー成分１００質量部に対し、０．１～１０質量部の範囲で使用することにより、懸濁の際に、油滴の粒子径を小さくすることができる。水溶性有機溶媒のより好ましい使用量は、モノマー成分１００質量部に対し、０．１～５質量部であり、さらに好ましくは１～５質量部である。水溶性有機溶媒としては、例えば、低級アルコール類；アセトン、メチルエチルケトン等のケトン類；酢酸エチル等のエステル類；ジオキサン、ジエチルエーテル等のエーテル類等が挙げられる。中でも、沸点が低いため揮発しやすく、乾燥後の粒子に残存しにくい点と、取扱いの容易さの点で、炭素数４以下のアルコールが好ましい。炭素数４以下の低級アルコールとしては、メチルアルコール、エチルアルコール、イソプロピルアルコール（ＩＰＡ）、ｎ－プロピルアルコール、ｎ－ブチルアルコール、イソブチルアルコール、ｓ－ブチルアルコールおよびｔ－ブチルアルコールが挙げられる。炭素数が３のＩＰＡ、ｎ－プロピルアルコールが好ましく、中でも、沸点のより低いＩＰＡは重合体微粒子を乾燥させる際に揮発しやすいため、最も好ましい。 In addition to water, a water-soluble organic solvent may be used. By using the water-soluble organic solvent in the range of 0.1 to 10 parts by mass with respect to 100 parts by mass of the monomer component, the particle diameter of oil droplets can be reduced during suspension. A more preferable amount of the water-soluble organic solvent is 0.1 to 5 parts by mass, more preferably 1 to 5 parts by mass with respect to 100 parts by mass of the monomer component. Examples of the water-soluble organic solvent include lower alcohols; ketones such as acetone and methyl ethyl ketone; esters such as ethyl acetate; ethers such as dioxane and diethyl ether. Among these, alcohols having 4 or less carbon atoms are preferred from the viewpoints that they have a low boiling point, are easily volatilized, and hardly remain in particles after drying, and are easy to handle. Examples of the lower alcohol having 4 or less carbon atoms include methyl alcohol, ethyl alcohol, isopropyl alcohol (IPA), n-propyl alcohol, n-butyl alcohol, isobutyl alcohol, s-butyl alcohol and t-butyl alcohol. IPA having 3 carbon atoms and n-propyl alcohol are preferable. Among them, IPA having a lower boiling point is most preferable because it easily volatilizes when polymer fine particles are dried.
　［ラジカル重合開始剤］
　ラジカル重合開始剤としては、従来公知の油溶性の過酸化物やアゾ系化合物が使用できる。例えば、過酸化物としては、ベンゾイルパーオキサイド、ラウロイルパーオキサイド、オクタノイルパーオキサイド、オルソクロロベンゾイルパーオキサイド、オルソメトキシベンゾイルパーオキサイド、メチルエチルケトンパーオキサイド、ジイソプロピルパーオキシジカーボネート、クメンハイドロパーオキサイド、シクロヘキサノンパーオキサイド、ｔ－ブチルハイドロパーオキサイド、ジイソプロピルベンゼンハイドロパーオキサイド等が挙げられる。また、アゾ系化合物としては、２，２’－アゾビスイソブチロニトリル、２，２’－アゾビス（２，４－ジメチルバレロニトリル）、２，２’－アゾビス（２，３－ジメチルブチロニトリル）、２，２’－アゾビス－（２－メチルブチロニトリル）、２，２’－アゾビス（２，３，３－トリメチルブチロニトリル）、２，２’－アゾビス（２－イソプロピルブチロニトリル）、１，１’－アゾビス（シクロヘキサン－１－カルボニトリル）、２，２’－アゾビス（４－メトキシ－２，４－ジメチルバレロニトリル）、２－（カルバモイルアゾ）イソブチロニトリル、４，４’－アゾビス（４－シアノバレリン酸）、ジメチル－２，２’－アゾビスイソブチレート等が挙げられる。 [Radical polymerization initiator]
As the radical polymerization initiator, conventionally known oil-soluble peroxides and azo compounds can be used. For example, peroxides include benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, orthochlorobenzoyl peroxide, orthomethoxybenzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxydicarbonate, cumene hydroperoxide, cyclohexanone peroxide. Examples thereof include oxide, t-butyl hydroperoxide, and diisopropylbenzene hydroperoxide. Examples of the azo compound include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2,3-dimethylbutyro). Nitrile), 2,2'-azobis- (2-methylbutyronitrile), 2,2'-azobis (2,3,3-trimethylbutyronitrile), 2,2'-azobis (2-isopropylbutyro) Nitrile), 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2- (carbamoylazo) isobutyronitrile, 4 4,4'-azobis (4-cyanovaleric acid), dimethyl-2,2'-azobisisobutyrate, and the like.
　重合開始剤は、モノマー成分１００質量部に対し、０．１～５質量部の範囲で使用するのが好ましい。より好ましくは１～５質量部である。また、上記重合開始剤はほとんどが油溶性であるので、予めモノマー成分に溶解させておいてから水に添加することが好ましい。 The polymerization initiator is preferably used in the range of 0.1 to 5 parts by mass with respect to 100 parts by mass of the monomer component. More preferably, it is 1 to 5 parts by mass. Moreover, since most of the polymerization initiators are oil-soluble, it is preferable to add them to water after dissolving them in the monomer component in advance.
　［分散安定剤］
　懸濁液中の油滴を安定化させて重合反応を円滑に進めるためには、分散安定剤を用いることが好ましい。分散安定剤としては、ポリビニルアルコール、ゼラチン、トラガント、デンプン、メチルセルロース、カルボキシメチルセルロース、ヒドロキシエチルセルロース、ポリアクリル酸ナトリウム、ポリメタクリル酸ナトリウム等の水溶性高分子；アニオン性界面活性剤；ノニオン性界面活性剤；カチオン性界面活性剤；両性イオン性界面活性剤、その他アルギン酸塩、ゼイン、カゼイン、硫酸バリウム、硫酸カルシウム、炭酸バリウム、炭酸マグネシウム、リン酸カルシウム、タルク、粘土、ケイソウ土、ベントナイト、水酸化チタン、水酸化ナトリウム、金属酸化物粉末等が用いられる。 [Dispersion stabilizer]
In order to stabilize the oil droplets in the suspension and facilitate the polymerization reaction, it is preferable to use a dispersion stabilizer. Examples of the dispersion stabilizer include polyvinyl alcohol, gelatin, tragacanth, starch, methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, sodium polyacrylate, polysodium methacrylate, and the like; anionic surfactants; nonionic surfactants Cationic surfactant; Zwitterionic surfactant, other alginate, zein, casein, barium sulfate, calcium sulfate, barium carbonate, magnesium carbonate, calcium phosphate, talc, clay, diatomaceous earth, bentonite, titanium hydroxide, water Sodium oxide, metal oxide powder, etc. are used.
　アニオン性界面活性剤としては、例えば、オレイン酸ナトリウム、ヒマシ油カリウム等の脂肪酸塩；ラウリル硫酸ナトリウム、ラウリル硫酸アンモニウム等のアルキル硫酸エステルエステル塩；ドデシルベンゼンスルホン酸ナトリウム等のアルキルベンゼンスルホン酸塩；アルキルナフタレンスルホン酸塩；アルカンスルホン酸塩；ジアルキルスルホコハク酸塩；アルキルリン酸エステル塩；ナフタレンスルホン酸ホルマリン縮合物；ポリオキシエチレンアルキルエーテル硫酸塩；ポリオキシエチレンフェニルエーテル硫酸エステル塩；ポリオキシエチレンアルキル硫酸エステル塩等が挙げられる。 Examples of the anionic surfactant include fatty acid salts such as sodium oleate and potassium castor oil; alkyl sulfate ester salts such as sodium lauryl sulfate and ammonium lauryl sulfate; alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate; alkylnaphthalene Sulfonate; Alkane sulfonate; Dialkyl sulfosuccinate; Alkyl phosphate ester salt; Naphthalene sulfonate formalin condensate; Polyoxyethylene alkyl ether sulfate; Polyoxyethylene phenyl ether sulfate salt; Polyoxyethylene alkyl sulfate ester Examples include salts.
　ノニオン性界面活性剤としては、ポリオキシエチレンアルキルエーテル、ポリオキシエチレンアルキルフェニルエーテル、ポリオキシエチレン脂肪酸エステル、ソルビタン脂肪酸エステル、ポリオキシソルビタン脂肪酸エステル、ポリオキシエチレンアルキルアミン、グリセリン脂肪酸エステル、オキシエチレン－オキシプロピレンブロックコポリマー等が挙げられる。 Nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxysorbitan fatty acid ester, polyoxyethylene alkylamine, glycerin fatty acid ester, oxyethylene- An oxypropylene block copolymer etc. are mentioned.
　カチオン性界面活性剤としては、ラウリルアミンアセテート、ステアリルアミンアセテート等のアルキルアミン塩；ラウリルトリメチルアルキルアンモニウムクロライド等の４級アンモニウム塩等がある。両性界面活性剤としては、ラウリルジメチルアミンオキサイド等が挙げられる。 Examples of the cationic surfactant include alkylamine salts such as laurylamine acetate and stearylamine acetate; quaternary ammonium salts such as lauryltrimethylalkylammonium chloride. Examples of amphoteric surfactants include lauryl dimethylamine oxide.
　分散安定剤の使用量は、モノマー成分１００質量部に対して０．０１～１０質量部が好ましく、より好ましくは０．０５～５質量部、さらに好ましくは１～２質量部である。 The amount of the dispersion stabilizer used is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, and still more preferably 1 to 2 parts by mass with respect to 100 parts by mass of the monomer component.
　［懸濁重合方法］
　懸濁重合方法に際しては、懸濁液を作るために、モノマー成分、水、ラジカル重合開始剤、必要に応じて分散安定剤および／または水溶性有機溶媒を反応容器へ添加する。このときの各成分の添加順序は特に限定されない。一例を挙げれば、次の通りである。まず、容器に、水と、分散安定剤を使用する場合は分散安定剤を仕込む。分散安定剤は水に溶解させてから仕込んでもよいし、容器の中でよく撹拌して溶解させてもよい。次に、この容器に、モノマー成分とラジカル重合開始剤とを容器に添加する。もちろんこの順序は逆でもよい。 [Suspension polymerization method]
In the suspension polymerization method, a monomer component, water, a radical polymerization initiator, and if necessary, a dispersion stabilizer and / or a water-soluble organic solvent are added to a reaction vessel to form a suspension. The order of adding each component at this time is not particularly limited. An example is as follows. First, when using water and a dispersion stabilizer in a container, the dispersion stabilizer is charged. The dispersion stabilizer may be charged after being dissolved in water, or may be dissolved by stirring well in a container. Next, a monomer component and a radical polymerization initiator are added to the container. Of course, this order may be reversed.
　次に、前記した方法および条件で、液滴形成を行う。すなわち、上記反応容器内の混合液をポンプ等を利用して、懸濁装置（例えばパイプラインミキサー）を通過させ、懸濁液を製造する。 Next, droplet formation is performed by the method and conditions described above. That is, the mixed solution in the reaction vessel is passed through a suspension device (for example, a pipeline mixer) using a pump or the like to produce a suspension.
　所望の懸濁液が得られたら、重合を行えばよい。具体的には、循環ラインを封鎖して、窒素等の不活性ガスで反応容器内を置換しながら加熱し、懸濁液を昇温させる。 When a desired suspension is obtained, polymerization may be performed. Specifically, the circulation line is blocked and heated while replacing the inside of the reaction vessel with an inert gas such as nitrogen to raise the temperature of the suspension.
　重合温度は、６０～１００℃であるのが好ましく、より好ましくは６５～９５℃、さらに好ましくは７０～９０℃である。重合反応は２～７時間とするのが好ましく、より好ましくは２．５～５時間であり、さらに好ましくは３～４．５時間である。また、重合反応は、ｐＨ４～１０の範囲で行うのが好ましい。 The polymerization temperature is preferably 60 to 100 ° C., more preferably 65 to 95 ° C., and further preferably 70 to 90 ° C. The polymerization reaction is preferably performed for 2 to 7 hours, more preferably 2.5 to 5 hours, and further preferably 3 to 4.5 hours. The polymerization reaction is preferably performed in the pH range of 4-10.
　懸濁重合の際、あるいは懸濁重合の後に、本発明法の目的を損なわない範囲で、公知の添加物を加えても構わない。具体的には、顔料、可塑剤、重合安定剤、蛍光増白剤、磁性粉、紫外線吸収剤、帯電防止剤、難燃剤等が挙げられる。 A known additive may be added during suspension polymerization or after suspension polymerization as long as the object of the present invention is not impaired. Specific examples include pigments, plasticizers, polymerization stabilizers, fluorescent brighteners, magnetic powders, ultraviolet absorbers, antistatic agents, and flame retardants.
　重合が終了したら、適宜、濾過、遠心分離、乾燥、解砕等を行う。本発明のビニル重合体微粒子は粗大粒子が低減されているので分級を行う必要はないが、異物等は濾過等の公知の方法で取り除いておくことが好ましい。なお、解砕とは、乾燥時に凝集した粒子を元の一次粒子に戻す（ほぐす）工程であり、一次粒子をさらに細かくする（破壊する）工程ではない。 When the polymerization is completed, filtration, centrifugation, drying, crushing, etc. are performed as appropriate. The vinyl polymer fine particles of the present invention do not need to be classified because coarse particles are reduced, but it is preferable to remove foreign matters by a known method such as filtration. In addition, crushing is a process of returning (aggregating) particles aggregated during drying to the original primary particles, and is not a process of further reducing (breaking) the primary particles.
　［用途］
　以上説明した、懸濁重合を利用して得られる本発明のビニル重合体微粒子は、粒子径の変動係数が所定値以上であり、粗大粒子の数が低減されたものである。従って、本発明のビニル重合体微粒子は、様々な用途、中でも光学用材料用添加剤やフィルム用添加剤として有用である。光学用材料用添加剤の具体例としては、例えば、ＬＣＤ等に用いる光拡散フィルムや導光板、あるいは、ＰＤＰ、ＥＬディスプレイおよびタッチパネル等に用いる光学用樹脂に含有させる光拡散剤やアンチブロッキング剤等の添加剤や、各種光学フィルム用のアンチブロッキング剤、滑剤等が好適な例として挙げられる。また、フィルム用添加剤としては、光学フィルムまたは光学フィルム以外の各種フィルムの各種添加剤（アンチブロッキング剤、滑剤、光拡散剤等）が好ましいものとして挙げられる。本発明のビニル重合体粒子は、光学フィルム用添加剤がより好ましい用途としてあげられる。さらに、本発明のビニル重合体粒子は、光拡散フィルム、防眩フィルム、反射防止フィルム等の光学フィルム用の光拡散剤として特に好ましい。 [Usage]
As described above, the vinyl polymer fine particles of the present invention obtained by utilizing suspension polymerization have a coefficient of variation in particle diameter of a predetermined value or more, and the number of coarse particles is reduced. Therefore, the vinyl polymer fine particles of the present invention are useful for various uses, particularly as an additive for optical materials and an additive for films. Specific examples of the additive for optical materials include, for example, a light diffusing film and a light guide plate used for LCDs, or a light diffusing agent and an anti-blocking agent contained in an optical resin used for PDP, EL display, touch panel and the like. Suitable additives include anti-blocking agents for various optical films, lubricants, and the like. Moreover, as an additive for films, various additives (an antiblocking agent, a lubricant, a light diffusing agent, etc.) of various films other than an optical film or an optical film are mentioned as a preferable thing. In the vinyl polymer particles of the present invention, an additive for optical films is more preferred. Furthermore, the vinyl polymer particles of the present invention are particularly preferred as a light diffusing agent for optical films such as light diffusing films, antiglare films, and antireflection films.
　なお、フィルム用添加剤として用いる場合、フィルムの薄膜化が進む中、添加剤としての微粒子の脱落が低減され、微粒子の添加目的（アンチブロッキング性、滑り性、光拡散性等の付与）を充分に発揮しやすい点から、ビニル重合体微粒子の体積平均粒子径は１０μｍ以下が好ましく、特に３．５μｍ以下であることが好ましい。 In addition, when used as an additive for a film, dropping of fine particles as an additive is reduced as the film becomes thinner, and the purpose of adding the fine particles (providing anti-blocking property, slipping property, light diffusibility, etc.) is sufficient. The volume average particle diameter of the vinyl polymer fine particles is preferably 10 μm or less, and particularly preferably 3.5 μm or less.
　本発明のビニル重合体微粒子は、光学用材料等の上述した用途以外の用途にも好適に用いることができる。例えば、静電荷像現像用トナー用添加剤、化粧板用添加剤、人工大理石用添加剤、クロマトグラフィーのカラム充填剤、液晶表示パネルのギャップ調整剤、コールターカウンターの表示粒子、免疫診断薬用担体、化粧料用添加剤等としても好適に用いられる。 The vinyl polymer fine particles of the present invention can be suitably used for applications other than those described above, such as optical materials. For example, additive for electrostatic image developing toner, additive for decorative plate, additive for artificial marble, column filler for chromatography, gap adjuster for liquid crystal display panel, display particle for coulter counter, carrier for immunodiagnostic drug, It is also suitably used as a cosmetic additive.
　［樹脂組成物］
　次に、本発明の樹脂組成物について説明する。なお、本発明の説明において、特に断りがない限り、樹脂組成物の加工形態として、板（状）、フィルム（状）という表現を用いるが、板（状）とは厚み１ｍｍ以上、フィルム（状）とは厚み１ｍｍ（１０００μｍ）未満を意味する。 [Resin composition]
Next, the resin composition of the present invention will be described. In the description of the present invention, unless otherwise specified, the expression “plate (form)” and “film (form)” is used as the processing form of the resin composition. ) Means a thickness of less than 1 mm (1000 μm).
　本発明の樹脂組成物とは、上述の本発明のビニル重合体微粒子を必須に含むものである。また、本発明の樹脂組成物には、透明のバインダー樹脂が含まれていてもよい。 The resin composition of the present invention essentially contains the above-described vinyl polymer fine particles of the present invention. Further, the resin composition of the present invention may contain a transparent binder resin.
　上記樹脂組成物中に含まれる微粒子量は、樹脂組成物の用途や所望の特性に応じて適宜決定すれば良いが、通常、光拡散板等の光学用途等の光学用材料に用いる場合であれば（下記（I）の態様）、バインダー樹脂１００質量部に対して０．０１質量部以上、２０質量部以下とするのが好ましい。より好ましくは０．０５質量部以上であり、さらに好ましくは０．１質量部以上、より好ましくは１０質量部以下であり、さらに好ましくは５質量部以下である。また、フィルム等の基材上に上記樹脂組成物を含む塗布液を塗工して得られる光拡散フィルム等の光学フィルムとして用いる場合であれば（下記（II）の態様）、バインダー樹脂１００質量部に対して５質量部以上、６００質量部以下とするのが好ましい。より好ましくは１０質量部以上、５００質量部以下であり、さらに好ましくは２０質量部以上、４００質量部以下である。ビニル重合体微粒子の含有量が多すぎる場合には、この樹脂組成物を使用して得られる成形体の強度が低下する場合があり、一方、少なすぎる場合には、ビニル重合体微粒子の使用による効果（光拡散性等）が得られ難い場合がある。 The amount of fine particles contained in the resin composition may be appropriately determined according to the use of the resin composition and desired properties, but is usually used for an optical material such as an optical use such as a light diffusion plate. (Aspect (I) below) is preferably 0.01 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin. More preferably, it is 0.05 mass part or more, More preferably, it is 0.1 mass part or more, More preferably, it is 10 mass part or less, More preferably, it is 5 mass part or less. In addition, when used as an optical film such as a light diffusion film obtained by coating a coating solution containing the resin composition on a substrate such as a film (aspect (II) below), the binder resin 100 mass It is preferable to set it as 5 to 600 mass parts with respect to a part. More preferably, it is 10 to 500 mass parts, More preferably, it is 20 to 400 mass parts. When the content of the vinyl polymer fine particles is too large, the strength of the molded product obtained using this resin composition may be reduced. On the other hand, when the content is too small, the use of the vinyl polymer fine particles may result. In some cases, it is difficult to obtain an effect (such as light diffusibility).
　上記樹脂組成物中に含まれる透明のバインダー樹脂は、特に限定されず、当該分野においてバインダー樹脂として使用されるものはいずれも用いることができる。例えば、（I）本発明の樹脂組成物を用いて形成される部材が、当該樹脂組成物そのものを板状、フィルム状等の形状に成形したものである場合（バインダー樹脂を、板状、フィルム状成形体の基材樹脂とする場合）であれば、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等のポリエステル系樹脂、アクリル系樹脂、ポリスチレン系樹脂、ポリエーテルサルホン系樹脂、ポリウレタン系樹脂、ポリカーボネート系樹脂、ポリスルホン系樹脂、ポリエーテル系樹脂、ポリメチルペンテン系樹脂、ポリエーテルケトン系樹脂、（メタ）アクリロニトリル系樹脂、ポリプロピレン系樹脂等のポリオレフィン系樹脂、ノルボルネン系樹脂、非晶質ポリオレフィン系樹脂、ポリアミド樹脂、ポリイミド樹脂、およびトリアセチルセルロース樹脂等が挙げられる。 The transparent binder resin contained in the resin composition is not particularly limited, and any resin used as a binder resin in the field can be used. For example, (I) When the member formed using the resin composition of the present invention is formed by molding the resin composition itself into a plate shape or a film shape (binder resin, plate shape, film In the case of a base resin of a molded product), a polyester resin such as polyethylene terephthalate or polyethylene naphthalate, an acrylic resin, a polystyrene resin, a polyether sulfone resin, a polyurethane resin, a polycarbonate resin, Polyolefin resins such as polysulfone resins, polyether resins, polymethylpentene resins, polyether ketone resins, (meth) acrylonitrile resins, polypropylene resins, norbornene resins, amorphous polyolefin resins, polyamide resins , Polyimide resin, and triacetylcellulose tree Examples include fats.
　また、（II）成形される部材が、予め準備された板状やフィルム状等の基材表面に、本発明の樹脂組成物を積層（コーティング、ラミネート等）して一体化させて成るものである場合、バインダー樹脂としては、例えば、アクリル系樹脂、ポリプロピレン樹脂、ポリビニルアルコール樹脂、ポリ酢酸ビニル樹脂、ポリスチレン樹脂、ポリカーボネート樹脂、フッ素樹脂、シリコーン樹脂、および、ポリウレタン樹脂等が挙げられる。 Further, (II) a member to be molded is formed by laminating (coating, laminating, etc.) the resin composition of the present invention on a previously prepared plate-like or film-like substrate surface. In some cases, examples of the binder resin include acrylic resins, polypropylene resins, polyvinyl alcohol resins, polyvinyl acetate resins, polystyrene resins, polycarbonate resins, fluororesins, silicone resins, and polyurethane resins.
　本発明の樹脂組成物は、上記ビニル重合体微粒子および透明のバインダー樹脂以外にも、本発明の効果を損なわない範囲であれば、必要に応じてその他の添加物を含んでいてもよい。その他の添加物としては、例えば、耐光性や耐ＵＶ性等の物性を高めるための紫外線吸収剤、架橋剤、蛍光増白剤、難燃剤等の各種添加剤等が挙げられる。これらは１種のみを用いてもよいし、２種以上を併用してもよい。 The resin composition of the present invention may contain other additives as necessary, as long as the effects of the present invention are not impaired, in addition to the vinyl polymer fine particles and the transparent binder resin. Examples of other additives include various additives such as an ultraviolet absorber, a crosslinking agent, a fluorescent brightening agent, and a flame retardant for enhancing physical properties such as light resistance and UV resistance. These may use only 1 type and may use 2 or more types together.
　本発明のビニル重合体微粒子は、光拡散性に優れ、高い輝度および高い透過性等、優れた光学特性を発現することができる。したがって、画像表示装置内において、光源からの光を画像表示面に均一に拡散させる光拡散フィルムや光拡散板等の光学用材料向けの光拡散剤として、特に好適に用いられる。なお、成形体の形状はフィルム状や板状に限られず、柱体、錐体、球等の成形体であっても良い。 The vinyl polymer fine particles of the present invention are excellent in light diffusibility, and can exhibit excellent optical properties such as high luminance and high transmittance. Therefore, it is particularly preferably used as a light diffusing agent for optical materials such as a light diffusing film and a light diffusing plate for uniformly diffusing light from the light source on the image display surface in the image display device. The shape of the molded body is not limited to a film shape or a plate shape, and may be a molded body such as a column, a cone, or a sphere.
　例えば、本発明の樹脂組成物から得られる成形体が、光拡散フィルムのようなフィルム状の成形体である場合、その形態としては、面状部分を有し、バインダー樹脂により、ビニル重合体微粒子が固定されてなる構成を少なくとも一部に有している形態が挙げられる。例えば、（i）樹脂組成物そのものを、板状に成形した形態（光拡散板）、（ii）予め準備した板状やフィルム状の基材表面の一部または全体に、上記樹脂組成物から成る層を積層し、一体化させた形態（光拡散フィルム等の光学フィルム）等が挙げられる。上記（i）、（ii）のいずれの形態の場合にも、透明バインダー樹脂中に本発明に係るビニル重合体微粒子が分散固定されているため、優れた光学特性を発揮することができる。 For example, when the molded product obtained from the resin composition of the present invention is a film-shaped molded product such as a light diffusing film, the form has a planar portion, and the vinyl polymer fine particles are formed by a binder resin. The form which has the structure formed by fixing at least in part. For example, (i) the resin composition itself is formed into a plate shape (light diffusing plate), (ii) a part of the plate-like or film-like substrate surface prepared in advance or on the entire surface from the resin composition And the like (stacking and integrating layers) (optical film such as a light diffusion film). In any of the above forms (i) and (ii), the vinyl polymer fine particles according to the present invention are dispersed and fixed in the transparent binder resin, so that excellent optical properties can be exhibited.
　なお、上記「面状部分を有する」とは、一般的には、光学部材の形状が板状、あるいはフィルム状のように、一定の面積の広がりを持った実質的に平らな表面部分が（ミクロンレベルでの凹凸を有する場合を含む）その形状の主たる構成要素となっていることを言うが、本発明では、このような態様には限られず、主たる構成要素ではなくても、その形状の少なくとも一部に実質的に平らな表面部分を有していればよい。また、光拡散フィルム等に用いる場合等は、光拡散性能を一層発揮させるために、上記面状部分には、本発明のビニル重合体微粒子の存在に基づく微細な突起が高い密度で形成されていることが好ましい。 The above-mentioned “having a planar portion” generally means that a substantially flat surface portion having a certain area spread, such as a plate shape or a film shape of an optical member ( Although it is said that it is the main component of the shape (including the case of having irregularities on the micron level), the present invention is not limited to such an embodiment, and even if it is not the main component, It is sufficient that at least a part of the surface is substantially flat. In addition, when used for a light diffusion film or the like, fine projections based on the presence of the vinyl polymer fine particles of the present invention are formed at a high density on the planar portion in order to further exhibit the light diffusion performance. Preferably it is.
　上記（i）の形態の成形体（光拡散板）を製造する方法としては、本発明の樹脂組成物を公知の押出機により溶融混練しながら押し出して板状（厚さ：１ｍｍ以上）およびフィルム状（厚さ：１～１０００μｍ未満）に成形する方法が挙げられる。また、フィルム状に成形された成形体を、従来公知の延伸装置を使用して一軸または二軸方向に延伸して、薄膜状の延伸フィルム（厚さ：５～１００μｍ）に成形することもできる。このとき、必要に応じて、耐光性や耐ＵＶ性等の物性を高めるため、上記樹脂組成物に各種添加剤や安定剤および難燃剤等の添加物を加えて成形してもよい。光学特性の均一な成形体を得るためには、上記樹脂組成物は、予め、バインダー樹脂中に本発明のビニル重合体微粒子を混合し、分散させておくことが好ましい。また同様に、上記添加物も樹脂組成物と混合しておいてもよい。バインダー樹脂と、ビニル重合体微粒子や添加物を混合する際には、押出機に供給する際に混合して用いてもよいし、これらをバインダー樹脂の一部と溶融混錬してマスターバッチを作製してから用いてもよい。成形体におけるビニル重合体微粒子の偏析を防止する観点からは、マスターバッチとして用いるのが好ましい。 As a method for producing the molded article (light diffusing plate) in the form of (i) above, the resin composition of the present invention is extruded while melting and kneading with a known extruder, and is in the form of a plate (thickness: 1 mm or more) and a film. And a method of forming into a shape (thickness: 1 to less than 1000 μm). In addition, a molded body formed into a film shape can be formed into a thin film-like stretched film (thickness: 5 to 100 μm) by stretching in a uniaxial or biaxial direction using a conventionally known stretching apparatus. . At this time, if necessary, in order to improve physical properties such as light resistance and UV resistance, various additives, additives such as a stabilizer and a flame retardant may be added to the resin composition. In order to obtain a molded article having uniform optical properties, the resin composition is preferably mixed and dispersed in advance with the vinyl polymer fine particles of the present invention in a binder resin. Similarly, the additive may be mixed with the resin composition. When mixing the binder resin with the vinyl polymer fine particles and additives, they may be mixed and used when fed to the extruder, or melted and kneaded with a part of the binder resin to prepare a master batch. You may use after producing. From the viewpoint of preventing segregation of the vinyl polymer fine particles in the molded product, it is preferably used as a master batch.
　上記（ii）の形態の成形体を得る方法としては、予め準備した基材表面に、本発明の樹脂組成物からなる層を積層する方法が挙げられる。積層方法は特に限定されず、樹脂組成物を有機溶剤（例えば、メタノール、エタノール、イソプロピルアルコール等のアルコール類；アセトン、メチルエチルケトン等のケトン類；トルエン、キシレン等の芳香族炭化水素類；酢酸エチル等のエステル類等）に分散または溶解させて、これを基材（例えば、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；トリアセチルセルロース；シクロポリオレフィン、非晶質ポリオレフィン等のオレフィン系ポリマー；ポリメチルメタクリレート、ラクトン環構造を有する（メタ）アクリレート等の（メタ）アクリレート樹脂系ポリマー；ポリスチレン樹脂；ポリカーボネート樹脂等）上に塗布すればよい（コーティング法、キャスト法等）。具体的な塗布方法としては、リバースロールコート法、グラビアコート法、ダイコート法、コンマコート法、およびスプレーコート法等の公知の積層方法が挙げられる。なお、基材には易接着層を設けても構わない。 Examples of the method for obtaining the molded article having the form (ii) include a method of laminating a layer made of the resin composition of the present invention on a previously prepared base material surface. The lamination method is not particularly limited, and the resin composition may be an organic solvent (for example, alcohols such as methanol, ethanol and isopropyl alcohol; ketones such as acetone and methyl ethyl ketone; aromatic hydrocarbons such as toluene and xylene; ethyl acetate and the like). In the form of a base material (eg, polyesters such as polyethylene terephthalate and polyethylene naphthalate); triacetyl cellulose; olefin polymers such as cyclopolyolefin and amorphous polyolefin; polymethyl methacrylate, (Meth) acrylate resin-based polymers such as (meth) acrylate having a lactone ring structure; polystyrene resin; polycarbonate resin, etc.) may be applied (coating method, cast method, etc.). Specific coating methods include known laminating methods such as reverse roll coating, gravure coating, die coating, comma coating, and spray coating. In addition, you may provide an easily bonding layer in a base material.
　また、基材表面に本発明の樹脂組成物を積層した後、従来公知の延伸装置により、樹脂組成物が積層された基材を一軸、または二軸方向に延伸させて延伸フィルムとしてもよい。この際、樹脂組成物の塗布のタイミングは特に限定されず、フィルムの製造工程のいずれかの段階で、樹脂組成物層を形成する方法（インライン方式）を採用し得る。また、上記基材を延伸して延伸フィルムを得た後、当該フィルム上に本発明の樹脂組成物からなる層を形成する方法（オフライン方式）も採用できる。 Alternatively, after the resin composition of the present invention is laminated on the surface of the substrate, the substrate on which the resin composition is laminated may be stretched uniaxially or biaxially by a conventionally known stretching apparatus to form a stretched film. At this time, the application timing of the resin composition is not particularly limited, and a method (in-line method) of forming the resin composition layer at any stage of the film production process can be adopted. Moreover, after extending | stretching the said base material and obtaining a stretched film, the method (offline system) of forming the layer which consists of a resin composition of this invention on the said film is also employable.
　本発明に係る光拡散フィルム等の光学フィルムの膜厚は３００μｍ以下、光拡散板の厚みは８ｍｍ以下であるのが好ましい。 The film thickness of the optical film such as the light diffusion film according to the present invention is preferably 300 μm or less, and the thickness of the light diffusion plate is preferably 8 mm or less.
　なお光拡散フィルム等の光学フィルムは、上記(i)の形態の製造方法に従って製造することもできる。また、必要に応じて得られた成形体を、一軸あるいは二軸方向に延伸してもよい。 An optical film such as a light diffusing film can also be produced according to the production method of the form (i). Moreover, you may extend | stretch the molded object obtained as needed to the uniaxial or biaxial direction.
　本願は２０１１年９月２９日に出願された日本国特許出願第２０１１-２１５６０９号に基づく優先権の利益を主張するものである。２０１１年９月２９日に出願された日本国特許出願第２０１１-２１５６０９号の明細書の全内容が、本願に参考のため援用される。 This application claims the benefit of priority based on Japanese Patent Application No. 2011-215609 filed on September 29, 2011. The entire contents of the specification of Japanese Patent Application No. 2011-215609 filed on September 29, 2011 are incorporated herein by reference.
　以下に、実施例により、本発明をさらに具体的に説明するが、本発明はこれらにより何ら限定されるものではない。なお、以下では、便宜上、「質量部」を単に「部」と記すことがある。また、「質量％」を「％」と記すことがある。まず、本発明の実施例において記載する測定方法について以下に示す。 Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto. Hereinafter, for convenience, “parts by mass” may be simply referred to as “parts”. In addition, “mass%” may be written as “%”. First, the measurement methods described in the examples of the present invention are described below.
　［重合体粒子の体積平均粒子径、粒子径の変動係数の測定］
　下記例で得られた分散液（粒子換算で０．００５部）または粉体０．００５部と、１質量％界面活性剤水溶液（「ネオペレックス（登録商標）Ｇ－１５」；ドデシルベンゼンスルフォン酸ナトリウム；花王株式会社製）２０部とを混合し、超音波で１０分間分散させて分散液を得た。この分散液を測定試料として、精密粒度分布測定装置（「コールターマルチサイザーIII型」；ベックマン・コールター社製）を用いて、体積基準の平均粒子径、粒子径の変動係数を求めた。なお、粒子径の変動係数は下記式により求めた値である。
粒子径の変動係数（％）＝１００×（粒子径の標準偏差／体積平均粒子径） [Measurement of volume average particle diameter and variation coefficient of particle diameter of polymer particles]
The dispersion (0.005 part in terms of particles) or powder obtained in the following example and 0.001 part of a 1% by weight surfactant aqueous solution (“Neoperex (registered trademark) G-15”; dodecylbenzene sulfonic acid 20 parts of sodium (manufactured by Kao Corporation) were mixed and dispersed with an ultrasonic wave for 10 minutes to obtain a dispersion. Using this dispersion as a measurement sample, a volume-based average particle diameter and a coefficient of variation of the particle diameter were determined using a precision particle size distribution analyzer (“Coulter Multisizer III type”; manufactured by Beckman Coulter, Inc.). The variation coefficient of the particle diameter is a value obtained by the following formula.
Variation coefficient of particle diameter (%) = 100 × (standard deviation of particle diameter / volume average particle diameter)
　［重合体粒子中の粗大粒子数と重合体粒子の最大粒子径］
　フロー式粒子像解析装置（「ＦＰＩＡ（登録商標）－３０００」;シスメックス社製）を用いて、粒子２５万個を測定対象として個数基準の粒度分布データを得て、得られた粒度分布データを元に、６．０４３μｍ以上の粒子（粗大粒子）全ての形状を画像で確認し、円形度が０．９７以上の粒子の個数を粗大粒子数とした。この測定を４回繰り返して、重合体粒子１００万個当たりの粗大粒子数とした。また、粗大粒子中、最も大きい粒子の粒子径を最大粒子径とした。４回の測定で得られた４個の最大粒子径のうち、最も大きい値を、当該粒子の最大粒子径とした。なお、下記表３に示す粉体の評価においては、各粉体の体積平均粒子径の２倍以上で、円形度が０．９７以上の粒子を粗大粒子としてカウントした。 [Number of coarse particles in polymer particles and maximum particle diameter of polymer particles]
Using a flow-type particle image analyzer (“FPIA (registered trademark) -3000”; manufactured by Sysmex Corporation), particle size distribution data on the basis of number was obtained using 250,000 particles as a measurement target, and the obtained particle size distribution data was Originally, the shape of all particles having a particle size of 6.043 μm or more (coarse particles) was confirmed by an image, and the number of particles having a circularity of 0.97 or more was defined as the number of coarse particles. This measurement was repeated four times to obtain the number of coarse particles per million polymer particles. Moreover, the particle diameter of the largest particle in the coarse particles was defined as the maximum particle size. Of the four maximum particle diameters obtained by four measurements, the largest value was defined as the maximum particle diameter of the particles. In the evaluation of the powder shown in Table 3 below, particles having a volume average particle diameter of 2 times or more and a circularity of 0.97 or more were counted as coarse particles.
　上記測定は、分散液（粒子換算で０．０５部）または粒子粉体０．０５部に、１．４質量％界面活性剤水溶液（「ネオペレックス（登録商標）Ｇ－１５」；ドデシルベンゼンスルフォン酸ナトリウム；花王株式会社製）を１７．５部加え、超音波で１０分間分散させた後に行った。 In the above measurement, a dispersion (0.05 parts in terms of particles) or 0.05 parts of particle powder was mixed with a 1.4% by mass aqueous surfactant solution (“Neoperex (registered trademark) G-15”; dodecylbenzenesulfone). 17.5 parts of sodium acid (manufactured by Kao Corporation) was added and dispersed by ultrasonic waves for 10 minutes.
　実験例１
　撹拌機、不活性ガス導入管、還流冷却器および温度計を備えた反応釜に、ポリオキシエチレンジスチリルフェニルエーテル硫酸エステルアンモニウム塩（「ハイテノール（登録商標）ＮＦ－０８」、第一工業製薬株式会社製）１部を溶解した脱イオン水溶液１５０部と、予め調製しておいたメタクリル酸メチル（ＭＭＡ）５０部、スチレン（Ｓｔ）４０部、トリメチロールプロパントリメタクリレート（ＴＭＰＴＭＡ）１０部、ラウリルパーオキサイド（ＬＰＯ）３部を溶解した単量体溶液を仕込み、混合液を得た。 Experimental example 1
In a reaction kettle equipped with a stirrer, inert gas introduction tube, reflux condenser and thermometer, polyoxyethylene distyryl phenyl ether sulfate ammonium salt (“Hytenol (registered trademark) NF-08”, Daiichi Kogyo Seiyaku) 150 parts of deionized aqueous solution with 1 part dissolved, 50 parts of methyl methacrylate (MMA) prepared in advance, 40 parts of styrene (St), 10 parts of trimethylolpropane trimethacrylate (TMPTMA), lauryl A monomer solution in which 3 parts of peroxide (LPO) was dissolved was charged to obtain a mixed solution.
　この混合液より、次のようにして懸濁液を得た。すなわち、パイプラインミキサーで、ｖ／Ｖ（ｖはミキサーの吐出量（ｍ3／ｈｒ）、Ｖは混合液総量（ｋｇ））が０．０２８３ｍ3／（ｈｒ・ｋｇ）となる一定条件下で、吐出量から換算して上記の混合液総量から２４パス相当となる時間、循環（段階（１））し、次いで、２５パス相当となる時間を、ｖ／Ｖが０．０３２２ｍ3／（ｈｒ・ｋｇ）の一定条件下で循環（段階（２））して、均一な懸濁液を得た。 From this mixed solution, a suspension was obtained as follows. That is, in a pipeline mixer, v / V (v is the discharge amount of the mixer (m 3 / hr), V is the total amount of the mixed solution (kg)) under a constant condition of 0.0283 m 3 / (hr · kg) Then, in terms of the discharge amount, circulation (stage (1)) is performed for a time corresponding to 24 passes from the total amount of the above mixed liquid, and then, the time corresponding to 25 passes is v / V of 0.0322 m 3 / (hr (Kg) was circulated under certain conditions (stage (2)) to obtain a uniform suspension.
　得られた懸濁液にさらに脱イオン水２５０部を添加した。その後、反応容器内に窒素ガスを吹き込みながら、液温が６０℃になるまで加熱して、反応容器を６０℃で保温した。自己発熱により液温が７５℃に達した時点を反応開始とし、９０分後、さらに液温を８５℃まで昇温させて、２時間攪拌し、重合反応を完了させた。体積平均粒子径３．１μｍ、変動係数３６．０％のビニル重合体微粒子が含有された分散液を得た。 Further, 250 parts of deionized water was added to the obtained suspension. Thereafter, while blowing nitrogen gas into the reaction vessel, the reaction vessel was heated to 60 ° C., and the reaction vessel was kept at 60 ° C. The reaction started when the liquid temperature reached 75 ° C. due to self-heating, and after 90 minutes, the liquid temperature was further raised to 85 ° C. and stirred for 2 hours to complete the polymerization reaction. A dispersion containing vinyl polymer fine particles having a volume average particle diameter of 3.1 μm and a coefficient of variation of 36.0% was obtained.
　得られた分散液から遠心沈降により微粒子を取り出し、乾燥機にて８０℃で乾燥を行い、水分量が０．５％以下となった時点で乾燥を完了した。乾燥後の微粒子をミルにて粗砕後、粉砕機で解砕処理した粉体を得た。この粉体の体積平均粒子径は３．１μｍ、変動係数は３６．３％、粗大粒子数（１００万個当たり）１１３個、最大粒子径９．３μｍであった。分散液の特性値を表２に、粉体化後の特性値を表３に示す。 Fine particles were taken out from the obtained dispersion by centrifugal sedimentation, dried at 80 ° C. with a dryer, and the drying was completed when the water content was 0.5% or less. The dried fine particles were coarsely crushed by a mill, and a powder crushed by a pulverizer was obtained. This powder had a volume average particle size of 3.1 μm, a coefficient of variation of 36.3%, a number of coarse particles (per 1 million particles) of 113, and a maximum particle size of 9.3 μm. Table 2 shows the characteristic values of the dispersion, and Table 3 shows the characteristic values after pulverization.
　実験例２
　実験例１と同様に混合液を調製した後、表１に示す条件で懸濁液を調製する以外は、実験例１と同様にして２段階で、均一な懸濁液を得た。その後、実験例１と同様にして、重合を行い、体積平均粒子径３．０μｍ、変動係数３６．５％のビニル重合体微粒子が含有された分散液を得た。 Experimental example 2
After preparing a mixed solution in the same manner as in Experimental Example 1, a uniform suspension was obtained in two steps in the same manner as in Experimental Example 1, except that a suspension was prepared under the conditions shown in Table 1. Thereafter, polymerization was carried out in the same manner as in Experimental Example 1 to obtain a dispersion containing vinyl polymer fine particles having a volume average particle size of 3.0 μm and a coefficient of variation of 36.5%.
　得られた分散液から遠心沈降により微粒子を取り出し、乾燥機にて８０℃で乾燥を行い、水分量が０．５％以下となった時点で乾燥を完了した。乾燥後の微粒子をミルにて粗砕後、粉砕機で解砕処理した粉体を得た。この粉体の体積平均粒子径は３．０μｍ、変動係数３５．９％、粗大粒子数（１００万個当たり）９５個、最大粒子径８．０μｍであった。分散液の特性値を表２に、粉体化後の特性値を表３に示す。 Fine particles were taken out from the obtained dispersion by centrifugal sedimentation, dried at 80 ° C. with a dryer, and the drying was completed when the water content was 0.5% or less. The dried fine particles were coarsely crushed by a mill, and a powder crushed by a pulverizer was obtained. This powder had a volume average particle size of 3.0 μm, a coefficient of variation of 35.9%, a number of coarse particles (per 1 million particles) of 95, and a maximum particle size of 8.0 μm. Table 2 shows the characteristic values of the dispersion, and Table 3 shows the characteristic values after pulverization.
　実験例３
　実験例１と同様に混合液を調製した後、表１に示す条件で１段階で懸濁液を調製した。それ以外は、実験例１と同様にして重合を行い、体積平均粒子径３．１μｍ、変動係数３７．０％のビニル重合体微粒子が含有された分散液を得た。分散液の一部を用いて、実験例１と同様にして粉体を製造した。分散液の特性値を表２に、粉体化後の特性値を表３に示す。 Experimental example 3
After preparing a mixed solution in the same manner as in Experimental Example 1, a suspension was prepared in one step under the conditions shown in Table 1. Otherwise, polymerization was carried out in the same manner as in Experimental Example 1 to obtain a dispersion containing vinyl polymer fine particles having a volume average particle diameter of 3.1 μm and a coefficient of variation of 37.0%. Using a part of the dispersion, powder was produced in the same manner as in Experimental Example 1. Table 2 shows the characteristic values of the dispersion, and Table 3 shows the characteristic values after pulverization.
　実験例４
　実験例１と同様に混合液を調製した後、表１に示す条件で１段階で懸濁液を調製した。それ以外は、実験例１と同様にして重合を行い、体積平均粒子径３．０μｍ、変動係数３９．４％のビニル重合体微粒子が含有された分散液を得た。分散液の一部を用いて、実験例１と同様にして粉体を製造した。分散液の特性値を表２に、粉体化後の特性値を表３に示す。 Experimental Example 4
After preparing a mixed solution in the same manner as in Experimental Example 1, a suspension was prepared in one step under the conditions shown in Table 1. Otherwise, polymerization was performed in the same manner as in Experimental Example 1 to obtain a dispersion containing vinyl polymer fine particles having a volume average particle size of 3.0 μm and a coefficient of variation of 39.4%. Using a part of the dispersion, powder was produced in the same manner as in Experimental Example 1. Table 2 shows the characteristic values of the dispersion, and Table 3 shows the characteristic values after pulverization.
　得られた粉体を、目開き５μｍのエレクトロンフィルターを用いて分級しようとしたが、すぐ目詰まりを起こし、分級することはできなかった。粗大粒子が原因だと考えられる。 The resulting powder was classified using an electron filter having an opening of 5 μm, but clogged immediately and could not be classified. It is thought that coarse particles are the cause.
　また、得られた粉体を、気流分級機（「ミクロンセパレーター」、ホソカワミクロン株式会社製）を用いて分級しようとしたが、配管中で閉塞を起こして、分級することはできなかった。帯電しやすいビニル重合体粒子のため、凝集して、配管を閉塞したものと考えられる。 Further, the obtained powder was classified using an airflow classifier (“Micron Separator”, manufactured by Hosokawa Micron Corporation), but could not be classified due to clogging in the piping. It is thought that because the vinyl polymer particles are easily charged, they aggregate and block the piping.
　実験例５
　実験例１と同様に混合液を調製した後、表１に示す条件で１段階で懸濁液を調製した。それ以外は、実験例１と同様にして重合を行い、体積平均粒子径２．８μｍ、変動係数３５．０％のビニル重合体微粒子が含有された分散液を得た。分散液の一部を用いて、実験例１と同様にして粉体を製造した。分散液の特性値を表２に、粉体化後の特性値を表３に示す。 Experimental Example 5
After preparing a mixed solution in the same manner as in Experimental Example 1, a suspension was prepared in one step under the conditions shown in Table 1. Otherwise, polymerization was carried out in the same manner as in Experimental Example 1 to obtain a dispersion containing vinyl polymer fine particles having a volume average particle diameter of 2.8 μm and a coefficient of variation of 35.0%. Using a part of the dispersion, powder was produced in the same manner as in Experimental Example 1. Table 2 shows the characteristic values of the dispersion, and Table 3 shows the characteristic values after pulverization.
　実験例６
　実験例１と同様に混合液を調製した後、表１に示す条件で２段階で懸濁液を調製し、均一な懸濁液を得た。その後、実験例１と同様にして重合を行い、体積平均粒子径３．１μｍ、変動係数３１．７％のビニル重合体微粒子が含有された分散液を得た。分散液の一部を用いて、実験例１と同様にして粉体を製造した。分散液の特性値を表２に、粉体化後の特性値を表３に示す。 Experimental Example 6
After preparing a mixed solution in the same manner as in Experimental Example 1, a suspension was prepared in two stages under the conditions shown in Table 1 to obtain a uniform suspension. Thereafter, polymerization was carried out in the same manner as in Experimental Example 1 to obtain a dispersion containing vinyl polymer fine particles having a volume average particle diameter of 3.1 μm and a coefficient of variation of 31.7%. Using a part of the dispersion, powder was produced in the same manner as in Experimental Example 1. Table 2 shows the characteristic values of the dispersion, and Table 3 shows the characteristic values after pulverization.
　実験例７
　実験例６で得られた分散液をデカンテーションし、得られた沈降物を再度水分散させて、デカンテーションを繰り返して微粒子を除去し、平均粒子径２．９μｍ、変動係数２６．２％のビニル重合体微粒子が含有された分散液を得た。分散液の一部を用いて、実験例１と同様にして粉体を製造した。分散液の特性値を表２に、粉体化後の特性値を表３に示す。 Experimental Example 7
The dispersion obtained in Experimental Example 6 was decanted, and the resulting precipitate was dispersed again in water, and the decantation was repeated to remove fine particles. The average particle size was 2.9 μm, and the coefficient of variation was 26.2%. A dispersion containing vinyl polymer fine particles was obtained. Using a part of the dispersion, powder was produced in the same manner as in Experimental Example 1. Table 2 shows the characteristic values of the dispersion, and Table 3 shows the characteristic values after pulverization.
　実験例８
　冷却管、撹拌機、温度計および滴下口を備えた反応容器に、イオン交換水８００部、２５モル％アンモニア水溶液１．６部、メタノール１１８部を入れ、撹拌しながら、３－メタクリロキシプロピルトリメトキシシラン（「ＫＢＭ－５０３」、信越化学株式会社製）２０部を滴下口から滴下して、３－メタクリロキシプロピルトリメトキシシランの加水分解縮合を行って、シード粒子となるメタクリロイル基を有するポリシロキサン粒子（重合性ポリシロキサン粒子）を調製した。反応開始から２時間後、得られた重合性ポリシロキサン粒子の乳濁液をサンプリングし、粒子径を測定したところ、個数平均粒子径は１．０μｍであった。 Experimental Example 8
In a reaction vessel equipped with a condenser, a stirrer, a thermometer, and a dripping port, put 800 parts of ion-exchanged water, 1.6 parts of a 25 mol% aqueous ammonia solution, and 118 parts of methanol while stirring. 20 parts of methoxysilane (“KBM-503”, manufactured by Shin-Etsu Chemical Co., Ltd.) is added dropwise from the dropping port, and hydrolytic condensation of 3-methacryloxypropyltrimethoxysilane is carried out to produce a polyacrylic polymer having methacryloyl groups as seed particles. Siloxane particles (polymerizable polysiloxane particles) were prepared. Two hours after the start of the reaction, the obtained emulsion of polymerizable polysiloxane particles was sampled and the particle diameter was measured. The number average particle diameter was 1.0 μm.
　別途、乳化剤として前記ハイテノールＮＦ－０８の２０％水溶液２．０部をイオン交換水１７５部に溶解させた溶液に、単量体としてのＳｔ８０部、ＭＭＡ１００部、エチレングリコールジメタクリレート（ＥＧＤＭＡ）２０部、および重合開始剤としての２，２’－アゾビス（２，４－ジメチルバレロニトリル）（「Ｖ－５２」、第一工業製薬株式会社製）２部の混合溶液を加え、乳化分散させてモノマーエマルションを調製した。 Separately, in a solution prepared by dissolving 2.0 parts of a 20% aqueous solution of Haitenol NF-08 as an emulsifier in 175 parts of ion-exchanged water, 80 parts of St, MMA 100 parts, ethylene glycol dimethacrylate (EGDMA) 20 as monomers. And 2 parts of 2,2′-azobis (2,4-dimethylvaleronitrile) (“V-52”, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as a polymerization initiator are added and emulsified and dispersed. A monomer emulsion was prepared.
　得られたモノマーエマルションを重合性ポリシロキサン粒子の乳濁液に添加して、撹拌を行った。モノマーエマルション添加から２時間後、乳濁液をサンプリングして顕微鏡で観察したところ、重合性ポリシロキサン粒子がモノマーエマルションを吸収して肥大化していることが確認できた。 The obtained monomer emulsion was added to an emulsion of polymerizable polysiloxane particles and stirred. Two hours after the addition of the monomer emulsion, the emulsion was sampled and observed with a microscope, and it was confirmed that the polymerizable polysiloxane particles absorbed the monomer emulsion and were enlarged.
　次いで、前記ハイテノールＮＦ－０８の２０％水溶液８部と、イオン交換水２０．６部を前記乳濁液に添加して、得られた反応液を窒素雰囲気下で６５℃まで昇温し、６５℃で２時間保持し、ラジカル重合を行った。ラジカル重合後の反応液を固液分離し、得られたケーキをイオン交換水、メタノールで洗浄した後、１００℃で６時間乾燥し、シード重合体粒子（粉体）を得た。この粉体の特性値を表３に示した。 Next, 8 parts of 20% aqueous solution of Haitenol NF-08 and 20.6 parts of ion-exchanged water were added to the emulsion, and the resulting reaction solution was heated to 65 ° C. under a nitrogen atmosphere. The mixture was held at 65 ° C. for 2 hours to perform radical polymerization. The reaction solution after radical polymerization was subjected to solid-liquid separation, and the obtained cake was washed with ion-exchanged water and methanol and then dried at 100 ° C. for 6 hours to obtain seed polymer particles (powder). The characteristic values of this powder are shown in Table 3.
　参考例１
　冷却ライン、撹拌機、温度計および滴下口を備えた反応釜に、メラミン１００部、ベンゾグアナミン１５０部、濃度３７％のホルマリン４００部および濃度１０％の炭酸ナトリウム水溶液１部を仕込み、アミノ樹脂前駆体形成用混合物を調製した。この混合物を撹拌しながら７０℃に昇温した後、７０℃で１．５時間保持し、初期縮合物を得た。 Reference example 1
A reaction kettle equipped with a cooling line, a stirrer, a thermometer and a dripping port was charged with 100 parts of melamine, 150 parts of benzoguanamine, 400 parts of formalin with a concentration of 37% and 1 part of an aqueous sodium carbonate solution with a concentration of 10%, and an amino resin precursor A forming mixture was prepared. The mixture was heated to 70 ° C. with stirring and then held at 70 ° C. for 1.5 hours to obtain an initial condensate.
　別途、前記ネオペレックス３０部をイオン交換水３０００部に溶解させて調製した界面活性剤溶液を７０℃で保持し、撹拌下、前記初期縮合物を投入し、アミノ樹脂前駆体乳濁液を得た。この乳濁液に濃度１％のドデシルベンゼンスルフォン酸水溶液２５０部を投入し、７０～９０℃で縮合、架橋させ、アミノ樹脂架橋粒子を含む懸濁液を得た。この懸濁液を濾過し、濾物を乾燥してアミノ樹脂架橋粒子の粉体を得た。この粉体の特性値を表３に示した。 Separately, a surfactant solution prepared by dissolving 30 parts of Neoperex in 3000 parts of ion-exchanged water is maintained at 70 ° C., and the initial condensate is added under stirring to obtain an amino resin precursor emulsion. It was. To this emulsion, 250 parts of an aqueous solution of dodecylbenzenesulfonic acid having a concentration of 1% was added and condensed and crosslinked at 70 to 90 ° C. to obtain a suspension containing amino resin crosslinked particles. This suspension was filtered, and the residue was dried to obtain a powder of amino resin crosslinked particles. The characteristic values of this powder are shown in Table 3.
　参考例２　
 冷却ライン、撹拌機、温度計および滴下口を備えた反応釜に、メラミン７５部、ベンゾグアナミン７５部、濃度３７％のホルマリン２９０部および濃度１０％の炭酸ナトリウム水溶液１部を仕込み、アミノ樹脂前駆体形成用混合物を調製した。この混合物を撹拌しながら８５℃に昇温した後、８５℃で１．５時間保持し、初期縮合物を得た。 Reference example 2
A reaction kettle equipped with a cooling line, a stirrer, a thermometer and a dripping port was charged with 75 parts of melamine, 75 parts of benzoguanamine, 290 parts of formalin with a concentration of 37% and 1 part of an aqueous sodium carbonate solution with a concentration of 10%, and an amino resin precursor A forming mixture was prepared. The mixture was heated to 85 ° C. while stirring and then held at 85 ° C. for 1.5 hours to obtain an initial condensate.
　別途、ドデシルベンゼンスルフォン酸ナトリウム７．５部をイオン交換水２４５５部に溶解させて調製した界面活性剤溶液を５０℃で保持し、撹拌下、前記初期縮合物を投入し、アミノ樹脂前駆体乳濁液を得た。この乳濁液に濃度５％のドデシルベンゼンスルフォン酸水溶液２９０部を投入し、７０～９０℃で縮合、架橋させ、アミノ樹脂架橋粒子を含む懸濁液を得た。この懸濁液を濾過し、濾物を乾燥してアミノ樹脂架橋粒子の粉体を得た。この粉体の特性値を表３に示した。 Separately, a surfactant solution prepared by dissolving 7.5 parts of sodium dodecylbenzenesulfonate in 2455 parts of ion-exchanged water is maintained at 50 ° C., and the initial condensate is added under stirring, and the amino resin precursor milk is added. A turbid liquid was obtained. To this emulsion, 290 parts of a 5% concentration of dodecylbenzenesulfonic acid aqueous solution was added and condensed and crosslinked at 70 to 90 ° C. to obtain a suspension containing amino resin crosslinked particles. This suspension was filtered, and the residue was dried to obtain a powder of amino resin crosslinked particles. The characteristic values of this powder are shown in Table 3.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
  ［光拡散フィルムとしての評価］　
 アクリル系樹脂（「ユーダブル（登録商標）Ｓ－２８４０」、株式会社日本触媒製）２２部、各実験例で得られた粉体２７部、トルエン３９部を、ディスパーで混合分散して混合液を得て、厚さ１００μｍのポリエチレンテレフタレートフィルム（「コスモシャイン（登録商標）Ａ－４３００」、東洋紡績株式会社製）の表面にバーコーターを用いて塗布して乾燥させ、厚み１０μｍの光拡散層が形成された各実験例に対応する光拡散フィルムを得た。
Figure JPOXMLDOC01-appb-T000003
 [Evaluation as a light diffusion film]
22 parts of an acrylic resin (“Udouble (registered trademark) S-2840”, manufactured by Nippon Shokubai Co., Ltd.), 27 parts of the powder obtained in each experimental example, and 39 parts of toluene were mixed and dispersed with a disper to prepare a mixed solution. Obtained and coated on the surface of a polyethylene terephthalate film having a thickness of 100 μm (“Cosmo Shine (registered trademark) A-4300”, manufactured by Toyobo Co., Ltd.) using a bar coater, a light diffusion layer having a thickness of 10 μm was formed. A light diffusion film corresponding to each experimental example formed was obtained.
　得られた光拡散フィルム（試料：縦１４８ｍｍ、横２１０ｍｍの長方形状）の表面に粗大粒子起因の欠点があるかないかを目視で観察し、欠点が認められないものを○、欠点が存在し、１５個以下であるものを△、欠点が１５個よりも多いものを×として評価した。 The surface of the obtained light diffusion film (sample: 148 mm long, 210 mm wide rectangular shape) is visually observed to see if there are any defects due to coarse particles. The evaluation was evaluated as Δ when the number was 15 or less, and X when there were more than 15 defects.
　また、輝度ムラの評価も行った。評価には、シャープ株式会社製の液晶テレビ「ＡＱＵＯＳ（登録商標）ＬＣ－３７ＡＤ」のバックライトユニットを用いた。このバックライトユニットは、光源と光拡散板を備えている。このバックライトユニットの光拡散板状に、各実験例の光拡散フィルムを載置し、光拡散フィルムから５０ｃｍ離れた位置に輝度計を設置し、任意の９箇所で正面輝度を測定し、輝度ムラを評価した。輝度ムラなしを○、僅かに輝度ムラありを△、輝度ムラありを×とした。さらに、光拡散フィルムを、通常の恒温恒湿機を用いて、３０℃、相対湿度９０％ＲＨの条件下に７日間放置した後の輝度ムラ（耐湿試験後の輝度ムラ）も評価した。光拡散フィルム表面の欠点、初期（耐湿試験前）の輝度ムラ、耐湿試験後の輝度ムラについての各評価結果を表４に示した。 Also, luminance unevenness was evaluated. For the evaluation, a backlight unit of a liquid crystal television “AQUAS (registered trademark) LC-37AD” manufactured by Sharp Corporation was used. This backlight unit includes a light source and a light diffusion plate. The light diffusing film of each experimental example is placed on the light diffusing plate of the backlight unit, a luminance meter is installed at a position 50 cm away from the light diffusing film, and the front luminance is measured at any nine locations. Unevenness was evaluated. No brightness unevenness was indicated by ○, slight brightness unevenness was indicated by Δ, and brightness unevenness was indicated by ×. Furthermore, the luminance unevenness (luminance unevenness after a humidity resistance test) after leaving the light diffusing film for 7 days under the conditions of 30 ° C. and relative humidity 90% RH was also evaluated using a normal temperature and humidity controller. Table 4 shows the evaluation results for the defects on the surface of the light diffusion film, the luminance unevenness at the initial stage (before the moisture resistance test), and the luminance unevenness after the moisture resistance test.
Figure JPOXMLDOC01-appb-T000004
 　実験例１、２、６、７はいずれも本発明例であり、粗大粒子に起因するフィルム表面の欠点がなく、輝度ムラも認められず、高性能な光拡散フィルムであった。実験例３～５は、粗大粒子数が多かったため、光拡散フィルムとした場合に、フィルム表面の欠点が目立ち、性能に劣るものであった。また、実験例８は粗大粒子は少ないものの、変動係数が小さい、即ち、粒度分布がシャープすぎて光拡散性が不足するため、輝度ムラが起こっていた。参考例１と２は、本発明のビニル重合体粒子とは異なるアミノ樹脂粒子に係る例であり、粗大粒子数が少ないためフィルム表面の欠点はなかったが、アミノ樹脂は耐湿性に劣るため、耐湿試験後の輝度ムラは本発明例に比べて劣っていることが確認できた。
Figure JPOXMLDOC01-appb-T000004
 Experimental Examples 1, 2, 6, and 7 were all examples of the present invention, and there were no defects on the film surface caused by coarse particles, no luminance unevenness was observed, and they were high-performance light diffusion films. In Experimental Examples 3 to 5, since the number of coarse particles was large, when a light diffusing film was used, defects on the film surface were conspicuous and the performance was inferior. In Experimental Example 8, although the coarse particles were small, the coefficient of variation was small, that is, the particle size distribution was too sharp and the light diffusibility was insufficient, resulting in luminance unevenness. Reference Examples 1 and 2 are examples relating to amino resin particles different from the vinyl polymer particles of the present invention, and since the number of coarse particles was small, there were no defects on the film surface, but the amino resin was poor in moisture resistance. It was confirmed that the luminance unevenness after the moisture resistance test was inferior to that of the example of the present invention.
　懸濁重合を利用して得られる本発明のビニル重合体微粒子は、比較的広い粒度分布を有するにもかかわらず、粗大粒子の数が低減されたものである。従って、本発明のビニル重合体微粒子は、様々な用途、例えば、ＬＣＤ等に用いる光拡散シートや導光板、あるいは、ＰＤＰ、ＥＬディスプレイおよびタッチパネル等に用いる光学用樹脂に含有させる光拡散剤やアンチブロッキング剤等の添加剤といった光学用途や、各種フィルム用のアンチブロッキング剤、滑剤等としても好適に用いられる。光学用材料以外にも、例えば静電荷像現像用トナー用添加剤、化粧板用添加剤、人工大理石用添加剤、クロマトグラフィーのカラム充填剤、液晶表示パネルのギャップ調整剤、コールターカウンターの表示粒子、免疫診断薬用担体、化粧料用添加剤等としても好適に用いられる。 The vinyl polymer fine particles of the present invention obtained by utilizing suspension polymerization have a reduced number of coarse particles despite having a relatively wide particle size distribution. Therefore, the vinyl polymer fine particles of the present invention are used in various applications, for example, a light diffusing sheet or light guide plate used for LCDs or the like, or a light diffusing agent or anti-light agent contained in an optical resin used for PDP, EL display and touch panel. It is also suitably used for optical applications such as additives such as blocking agents, anti-blocking agents for various films, lubricants, and the like. In addition to optical materials, for example, toner additive for developing electrostatic image, decorative plate additive, artificial marble additive, chromatography column filler, liquid crystal display panel gap adjuster, coulter counter display particle It is also preferably used as a carrier for immunodiagnostics, an additive for cosmetics, and the like.
　また、本発明の製造方法は、懸濁装置を用いて２段階での懸濁を行うだけであるので、粗大粒子数が低減されたビニル重合体微粒子を簡単に製造することができ、工業的に極めて有用な方法である。 In addition, since the production method of the present invention only involves suspension in two stages using a suspension device, vinyl polymer fine particles with a reduced number of coarse particles can be easily produced, This is a very useful method.

Claims (16)

  1. 　体積基準の粒子径の変動係数が１０％以上であり、体積平均粒子径の２倍以上の粒子径を有する粗大粒子の数が、微粒子１００万個中、１８０個以下であることを特徴とするビニル重合体微粒子。 The coefficient of variation of the volume-based particle diameter is 10% or more, and the number of coarse particles having a particle diameter more than twice the volume average particle diameter is 180 or less in 1 million fine particles. Vinyl polymer fine particles.
  2. 　芳香環を有するビニル重合体の微粒子である請求項１に記載のビニル重合体微粒子。 The vinyl polymer fine particles according to claim 1, which are vinyl polymer fine particles having an aromatic ring.
  3. 　ビニル重合体中の無機質成分が２質量％以下である請求項１または２に記載のビニル重合体微粒子。 The vinyl polymer fine particles according to claim 1 or 2, wherein an inorganic component in the vinyl polymer is 2% by mass or less.
  4. 　光学用材料用添加剤および／またはフィルム用添加剤である請求項１～３のいずれか１項に記載のビニル重合体微粒子。 The vinyl polymer fine particle according to any one of claims 1 to 3, which is an additive for optical materials and / or an additive for films.
  5. 　光学フィルムに添加されるものである請求項１～４のいずれか１項に記載のビニル重合体微粒子。 The vinyl polymer fine particle according to any one of claims 1 to 4, which is added to an optical film.
  6. 　光拡散剤として用いられるものである請求項１～５のいずれか１項に記載のビニル重合体微粒子。 The vinyl polymer fine particles according to any one of claims 1 to 5, which are used as a light diffusing agent.
  7. 　請求項１～６のいずれかに記載のビニル重合体微粒子を製造する方法であって、水、モノマー成分およびラジカル重合開始剤を含む混合液を、懸濁装置に導入して懸濁させ液滴を形成する液滴形成工程と、重合工程とを含み、前記液滴形成工程は少なくとも段階（１）と段階（２）とからなり、段階（１）における剪断力よりも段階（２）における剪断力を大きくすることを特徴とするビニル重合体微粒子の製造方法。 A method for producing the vinyl polymer fine particles according to any one of claims 1 to 6, wherein a mixed liquid containing water, a monomer component and a radical polymerization initiator is introduced into a suspension device, suspended, and dropped. A droplet forming step for forming the step and a polymerization step, wherein the droplet forming step comprises at least step (1) and step (2), and the shearing force in step (2) is higher than the shearing force in step (1). A method for producing vinyl polymer fine particles characterized by increasing force.
  8. 　上記懸濁装置がパイプラインミキサーである請求項７に記載のビニル重合体微粒子の製造方法。
    The method for producing fine vinyl polymer particles according to claim 7, wherein the suspension device is a pipeline mixer.
  9. 上記懸濁装置に導入する混合液の総量をＶ（ｋｇ）、懸濁装置からの吐出量をｖ（ｍ3／ｈｒ）とするときに、段階（１）におけるｖ／Ｖよりも段階（２）におけるｖ／Ｖを大きくするものである請求項７または８に記載のビニル重合体微粒子の製造方法。 When the total amount of the mixed liquid introduced into the suspension device is V (kg) and the discharge amount from the suspension device is v (m 3 / hr), the step (2) is higher than the v / V in step (1) (2 9) The method for producing vinyl polymer fine particles according to claim 7 or 8, wherein v / V is increased.
  10. 　段階（１）におけるｖ／Ｖを、０．０１ｍ3／（ｈｒ・ｋｇ）以上、０．１０ｍ3／（ｈｒ・ｋｇ）以下とする請求項７～９のいずれか１項に記載のビニル重合体微粒子の製造方法。 V / V to in step (1), 0.01m 3 / ( hr · kg) or more, the vinyl according to any one of claims 7 to 9, 0.10m 3 / (hr · kg) or less heavy A method for producing coalesced fine particles.
  11. 　請求項１～６のいずれか１項に記載のビニル重合体微粒子を含むことを特徴とする樹脂組成物。 A resin composition comprising the vinyl polymer fine particles according to any one of claims 1 to 6.
  12. 　請求項１～６のいずれか１項に記載のビニル重合体微粒子を含むことを特徴とする光学用材料。 An optical material comprising the vinyl polymer fine particles according to any one of claims 1 to 6.
  13. 　請求項１～６のいずれか１項に記載のビニル重合体微粒子を含むことを特徴とするフィルム。 A film comprising the vinyl polymer fine particles according to any one of claims 1 to 6.
  14. 　請求項１～６のいずれか１項に記載のビニル重合体微粒子を含むことを特徴とする光学フィルム。 An optical film comprising the vinyl polymer fine particles according to any one of claims 1 to 6.
  15. 　基材フィルムの少なくとも片面に、請求項１１に記載の樹脂組成物を含む塗布液を塗工して得られるものであることを特徴とする光学フィルム。 An optical film obtained by coating a coating liquid containing the resin composition according to claim 11 on at least one surface of a base film.
  16. 　光拡散フィルムである請求項１５に記載の光学フィルム。
          The optical film according to claim 15, which is a light diffusion film.
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