JP2008007666A - Optical material composition, method for producing the same, and optical material molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical material composition that can provide an optical material molded article excellent in glareproof, and to provide a method for producing the same, as well as to provide an optical material molded article excellent in glareproof. <P>SOLUTION: The optical material composition comprises a polymer particle, that is highly crosslinked and whose number average particle diameter is 0.1-20 μm and a coefficient of variation (CV value) of particle diameter distribution is not more than 20%, and a binder component. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical material composition capable of providing an optical material molded article having excellent antiglare properties, a method for producing the same, and an optical material molded article having excellent antiglare properties.

  Currently, liquid crystal display devices are used as display devices for televisions, personal computers, and the like. When the transmitted light or reflected light is not properly diffused on the surface, this liquid crystal display device looks very dazzling when viewed from the front or reflects light from the surrounding environment such as a fluorescent lamp as it is. There were problems such as the image being reflected (so-called “glare”). In order to prevent the above problems, an antiglare film is usually provided on the surface of the liquid crystal display device.

  As this anti-glare film, a film containing particles made of a synthetic resin is disclosed (for example, see Patent Document 1). The film described in Patent Document 1 has an antiglare property without reducing permeability by setting the thickness of the binder layer to a predetermined ratio with respect to the number average particle diameter of the particles contained in the film. To demonstrate.

JP-A-8-30991

  However, even with the antiglare film described in Patent Document 1, there is still room for improvement with respect to the antiglare property, and an optical material molded product (antiglare film) with higher properties and such an optical component are still available. Development of a material capable of producing a molded material (antiglare film) is desired.

  The present invention has been made in view of such problems of the prior art, and is a composition for an optical material capable of providing an optical material molded article having excellent antiglare properties, a method for producing the same, and antiglare properties. An excellent optical material molded article is provided.

  As a result of intensive studies to solve the above problems, the present inventors have found that the number average particle diameter and the coefficient of variation of the particle diameter distribution are within a predetermined numerical range, and are highly crosslinked polymer particles, a binder component, The present inventors have found that the above-described problems can be solved by using a composition for optical materials containing the present invention, and completed the present invention. Specifically, the present invention provides the following composition for optical materials, a method for producing the same, and an optical material molded article.

[1] A composition for an optical material comprising high cross-links, polymer particles having a number average particle size of 0.1 to 20 μm and a particle size distribution variation coefficient (CV value) of 20% or less, and a binder component. object.

[2] The composition for optical materials according to [1], wherein the polymer particles include a structural unit derived from an aromatic vinyl monomer or a structural unit derived from an acrylic acid monomer.

[3] The polymer particles according to [1] or [2], in which a 10% weight loss temperature (T ₁₀ ) by thermogravimetric analysis is 320 ° C. or more and a soluble content in toluene is 10% or less. A composition for optical materials.

[4] By causing the polymer particles to absorb the polymerizable monomer containing 5% by mass or more of the crosslinkable monomer in the monodisperse particles of the styrenic polymer and seed emulsion polymerization in the presence of the first radical polymerization initiator. The composition for optical materials according to any one of [1] to [3], which is the obtained first emulsion polymerization particle.

[5] By causing the polymer particles to absorb the polymerizable monomer containing 5% by mass or more of the crosslinkable monomer in the monodisperse particles of the styrene polymer, and seed emulsion polymerization in the presence of the first radical polymerization initiator. The first emulsion polymerization particles obtained are the second emulsion polymerization particles obtained by absorbing the polymerizable monomer and further seed emulsion polymerization in the presence of a second radical polymerization initiator [ The composition for optical materials according to any one of [1] to [3].

[6] The solvent is removed from an emulsion containing polymer particles and a solvent that is highly crosslinked, has a number average particle size of 0.1 to 20 μm, and has a coefficient of variation (CV value) of particle size distribution of 20% or less. And the manufacturing method of the composition for optical materials which has the process of obtaining the said polymer particle of a dry state, and the process of mixing the obtained said polymer particle and a binder component.

[7] An optical material molded article comprising the composition for optical materials according to any one of [1] to [5].

[8] The optical material molded article according to [7], which is an antiglare film, a light diffusion film, a light diffusion plate, a polarizing plate, or a light guide plate.

[9] A base material layer and an antiglare layer formed on the at least one surface of the base material layer and made of the composition for optical materials according to any one of [1] to [5]. Anti-glare film provided.

  The composition for optical materials of the present invention exhibits an effect that an optical material molded article having excellent antiglare properties can be provided.

  According to the method for producing an optical material composition of the present invention, an optical material composition capable of providing an optical material molded article excellent in antiglare property can be produced.

  The optical material molded product of the present invention has an effect of being excellent in antiglare property.

  The antiglare film of the present invention exhibits excellent antiglare properties.

  Hereinafter, the best mode for carrying out the present invention will be described, but the present invention is not limited to the following embodiment. That is, it is understood that modifications and improvements as appropriate to the following embodiments are also within the scope of the present invention based on ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. Should be.

[1] Composition for optical material:
The composition for optical materials of the present invention is highly crosslinked, has a number average particle size of 0.1 to 20 μm, and has a coefficient of variation of particle size distribution (hereinafter sometimes referred to as “CV value”) of 20% or less. It contains certain polymer particles and a binder component. When an optical material molded product is formed from this optical material composition, there is an effect that an optical material molded product having excellent antiglare properties can be obtained. In particular, it is suitable to use as an antiglare film.

[1-1] Polymer particles:
The polymer particles of the composition for optical materials of the present invention have a number average particle diameter of 0.1 to 20 μm. The number average particle diameter of the polymer particles is preferably 0.3 to 15 μm, more preferably 0.5 to 10 μm. If the number average particle diameter of the polymer particles is less than 0.1 μm, light cannot be sufficiently scattered, and there is a tendency that it becomes difficult to produce an optical material molded article that exhibits sufficient antiglare performance. . On the other hand, when it exceeds 20 μm, it tends to be difficult to produce by seed emulsion polymerization. In the present specification, “number average particle diameter” refers to a value measured by a light scattering method.

  Moreover, the polymer particle of the composition for optical materials of the present invention has a variation coefficient (CV value) of particle size distribution of 20% or less. The CV value is preferably 18% or less, more preferably 16% or less. If the CV value exceeds 20%, it tends to be difficult to obtain uniform optical characteristics. In the present specification, “the coefficient of variation (CV value) of the particle size distribution” refers to a value measured by a light scattering method.

Furthermore, the polymer particles of the composition for optical materials of the present invention are highly crosslinked. In the present specification, “highly cross-linked” means that the content of the cross-linked structure in the polymer is high, and therefore means excellent heat resistance and solvent resistance. Here, the polymer particles that are highly crosslinked specifically have a 10% weight loss temperature (T ₁₀ ) by thermogravimetric analysis (hereinafter sometimes referred to as “10% thermogravimetric temperature decrease”) of 320 ° C. or higher. In addition, polymer particles having a soluble content in toluene (hereinafter sometimes referred to as “toluene-soluble content”) of 10% or less can be obtained. By containing such highly crosslinked polymer particles, for example, even when an organic solvent is used as a dispersion medium for the polymer particles, the shape of the particles can be easily maintained and the effect of being hardly affected by heat can be obtained. . The “10% weight loss temperature by thermogravimetric analysis (T ₁₀ )” is the value when 10% by mass of the initial mass is reduced when heated at a rate of 20 ° C./min under a nitrogen atmosphere in the TGA thermobalance method. Temperature. The “soluble matter in toluene” refers to the mass ratio of solids (polymer particles) remaining in toluene to the total solids (polymer particles) before immersion in toluene.

  The 10% thermal weight loss temperature is preferably 335 ° C. or higher, more preferably 350 ° C. or higher. If the 10% thermal weight loss temperature is less than 320 ° C., when an organic solvent is used as the dispersion medium for the polymer particles, the shape of the particles is difficult to maintain and there is a risk of being altered by heat. The toluene soluble content is preferably 8% or less, more preferably 5% or less. If the toluene-soluble content exceeds 10%, the same problem as that in which the 10% thermogravimetric reduction temperature is less than 320 ° C. tends to occur.

  As long as the polymer particles of the composition for optical materials of the present invention satisfy the above conditions, the constitution of the polymer particles is not limited, but a structural unit derived from an aromatic vinyl monomer (hereinafter referred to as “structural unit (a1) ) ”Or a structural unit derived from an acrylic acid monomer (hereinafter, sometimes referred to as“ structural unit (a2) ”).

  Examples of the aromatic vinyl monomer that can be used for constituting a structural unit derived from an aromatic vinyl monomer include styrene, α-methylstyrene, vinyltoluene, p-methylstyrene, 2-methylstyrene, and 3-methyl. Styrene, 4-methylstyrene, 4-ethylstyrene, 4-tert-butylstyrene, 3,4-dimethylstyrene, 4-methoxystyrene, 4-ethoxystyrene, 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene 2,4-dichlorostyrene, 2,6-dichlorostyrene, 4-chloro-3-methylstyrene, divinylbenzene, 1-vinylnaphthalene, 2-vinylpyridine, 4-vinylpyridine and the like. Of these, styrene, divinylbenzene, and α-methylstyrene are preferable. These aromatic vinyl monomers can be used singly or in combination of two or more.

  The proportion of the structural unit (a1) contained in the polymer particles is preferably 1 to 100% by mass, and 50 to 100% by mass, when the total of the structural units contained in the polymer particles is 100% by mass. It is more preferable that it is 80-100 mass%. When the proportion of the structural unit (a1) is less than 20% by mass, the polymerization stability tends to deteriorate.

  Examples of the acrylic acid monomer that can be used for constituting the structural unit derived from the acrylic acid monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and n-hexyl (meth). (Cyclo) alkyl (meth) acrylates such as acrylate, 2-ethylhexyl (meth) acrylate, and cyclohexyl (meth) acrylate; alkoxy (cyclo) such as 2-methoxyethyl (meth) acrylate and p-methoxycyclohexyl (meth) acrylate Examples include alkyl (meth) acrylates; polyvalent (meth) acrylates such as trimethylolpropane tri (meth) acrylate; vinyl esters such as vinyl acetate, vinyl propionate, and vinyl versatate. Of these, methyl (meth) acrylate is preferable. These acrylic acid monomers can be used singly or in combination of two or more.

  The proportion of the structural unit (a2) contained in the polymer particles is preferably 0 to 99% by mass, when the total of all the structural units contained in the polymer particles is 100% by mass, and 0 to 50%. It is more preferable that it is mass%, and it is especially preferable that it is 0-20 mass%. If the proportion of the structural unit (a2) is more than 99% by mass, good seed polymerization tends to be difficult.

  The polymer particles include, in addition to the structural unit (a1) or the structural unit (a2), a monomer unit (also referred to as a structural unit (a3)) composed of other monomers copolymerizable with the above-described various monomers as necessary. It may be included. Examples of other monomers constituting the structural unit (a3) include those shown below.

  N-methylol unsaturated carboxylic acid amides such as N-methylol (meth) acrylamide and N, N-dimethylol (meth) acrylamide; aminoalkyl group-containing acrylamides such as 2-dimethylaminoethylacrylamide; (meth) acrylamide; Amides or imides of unsaturated carboxylic acids such as N-methoxymethyl (meth) acrylamide, N, N-ethylenebis (meth) acrylamide, maleic acid amide, maleimide; N-methylacrylamide, N, N-dimethylacrylamide, etc. N-monoalkyl (meth) acrylamides, N, N-dialkylacrylamides; aminoalkyl group-containing (meth) acrylates such as 2-dimethylaminoethyl (meth) acrylate; 2- (dimethylaminoethoxy) ethyl (meth) Acry (Meth) acrylates containing aminoalkoxyalkyl groups such as vinylate; halogenated vinyl compounds such as vinyl chloride, vinylidene chloride and fatty acid vinyl ester; 1,3-butadiene, 2-methyl-1,3-butadiene, 2 -Conjugated diene compounds such as chloro-1,3-butadiene and 2,3-dimethyl-1,3-butadiene,

  (Meth) acrylic acid, crotonic acid, cinnamic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, monomethyl maleate, monoethyl maleate, monomethyl itaconate, monoethyl itaconate, hexahydrophthal Carboxyl group-containing unsaturated monomers such as acid mono-2- (meth) acryloyloxyethyl, and anhydrides thereof, vinyl cyanide monomers such as (meth) acrylonitrile, crotonnitrile, cinnamate nitrile; 2-cyanoethyl (meth) acrylate, 2-cyanopropyl (meth) acrylate, 3-cyanopropyl (meth) acrylate, hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate 4-hydroxycyclohex Hydroxy (cyclo) alkyl mono (meth) acrylates such as ru (meth) acrylate and neopentyl glycol mono (meth) acrylate; 3-chloro-2-hydroxypropyl (meth) acrylate, 3-amino-2-hydroxypropyl ( Examples thereof include substituted hydroxy (cyclo) alkyl mono (meth) acrylates such as (meth) acrylate, allyl glycidyl ether, glycidyl (meth) acrylate, methyl glycidyl methyl acrylate, epoxidized cyclohexyl (meth) acrylate, and the like.

[1-2] Method for producing polymer particles:
The polymer particles of the composition for optical materials of the present invention are not particularly limited in the production method, but the monodisperse particles of the styrenic polymer absorb a polymerizable monomer containing 5% by mass or more of a crosslinkable monomer, The first emulsion polymerized particles (hereinafter referred to as “polymer particles (a)”) obtained by seed emulsion polymerization (hereinafter sometimes referred to as “seed polymerization”) in the presence of the radical polymerization initiator ) Is preferable.

  As the “monodisperse particle of styrene polymer” for absorbing the polymerizable monomer, for example, monodisperse polystyrene particles can be used, and the monodisperse particles preferably have a weight average molecular weight of 500 to 20000, It is more preferable that it is 15000, and it is especially preferable that it is 500-10000. The monodispersed particles can be obtained by a usual emulsion polymerization method using an aqueous medium, and the number average particle diameter is preferably 0.05 to 1.5 μm, and preferably 0.1 to 1 μm. Is more preferable. The “weight average molecular weight” can be measured using polystyrene as a standard substance by a gel permeation chromatography (GPC) method which has already been widely adopted as a general measurement method.

  The “aqueous medium” means a medium mainly composed of water. Specifically, the water content in the aqueous medium is preferably 40% by mass or more, and more preferably 50% by mass or more. Other media that can be used in combination with water include compounds such as esters, ketones, phenols, and alcohols.

  As the polymerizable monomer to be absorbed by the monodisperse particles, those containing 5% by mass or more of a crosslinkable monomer can be suitably used. Examples of the “polymerizable monomer” include styrene, α-methylstyrene, vinyltoluene, p-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-ethylstyrene, 4-tert-butyl. Styrene, 3,4-dimethylstyrene, 4-methoxystyrene, 4-ethoxystyrene, 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 2,4-dichlorostyrene, 2,6-dichlorostyrene, 4- Chloro-3-methylstyrene, 1-vinylnaphthalene, 2-vinylpyridine, 4-vinylpyridine, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-hexyl (meth) acrylate, 2 -Ethylhexyl (meth) acrylate, cyclohexyl (medium ) (Cyclo) alkyl (meth) acrylates such as acrylate; alkoxy (cyclo) alkyl (meth) acrylates such as 2-methoxyethyl (meth) acrylate and p-methoxycyclohexyl (meth) acrylate, vinyl acetate, vinyl propionate And vinyl esters such as vinyl versatate. Among these, styrene and methyl methacrylate are preferable.

  Further, as the “crosslinkable monomer”, for example, at least two or more of non-conjugated vinyl compounds typified by divinylbenzene (DVB) or polyvalent acrylate compounds typified by trimethylolpropane trimethacrylate (TMPMA) A monomer having a copolymerizable double bond can be cited as a preferred example. Examples of the polyvalent acrylate compounds that can be used in the present invention include diacrylate compounds such as polyethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,6-hexane glycol diacrylate, and polypropylene glycol diacrylate. Triacrylates such as trimethylolpropane triacrylate, tetramethylolmethane triacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4 butylene Glycol dimethacrylate, 1,6-hexane glycol dimethacrylate, neopentyl glycol di Dimethacrylates such as methacrylate, trimethylolpropane trimethacrylate, tri methacrylates such as trimethylolpropane trimethacrylate and the like. Among these, it is particularly preferable to use divinylbenzene, ethylene glycol dimethacrylate, or trimethylolpropane trimethacrylate. Moreover, these crosslinkable monomers can also be used in mixture of 2 or more types.

  The content of the crosslinkable monomer is preferably 5% by mass or more, more preferably 10 to 50% by mass, and particularly preferably 20 to 50% by mass with respect to 100% by mass of the polymerizable monomer. . If the content of the crosslinkable monomer is less than 5% by mass, it may be difficult to obtain polymer particles having a sufficient crosslinked structure.

  The conditions of “seed emulsion polymerization” may be in accordance with known methods. For example, when the total amount of monomers used is 100 parts, usually 100 to 500 parts of water is used, and the polymerization temperature is -10 to 100 ° C (preferably -5 to 100 ° C, more preferably 0 to 90 ° C. ), Polymerization time can be carried out under conditions of 0.1 to 30 hours (preferably 2 to 25 hours). Emulsion polymerization methods include batch method in which monomers are charged all at once, a method in which monomers are divided or continuously supplied, a method in which monomer pre-emulsions are divided or continuously added, or a combination of these methods in stages. Can be adopted. Moreover, the molecular weight regulator used for normal emulsion polymerization, a chelating agent, an inorganic electrolyte, etc. can be used 1 type, or 2 or more types as needed.

  As the first radical polymerization initiator used in the seed emulsion polymerization, persulfates such as potassium persulfate and ammonium persulfate; benzoyl peroxide, lauroyl peroxide, tert-butylperoxy-2-ethylhexanoate, etc. Organic peroxides; azo compounds such as azobisisobutyronitrile, dimethyl-2,2'-azobisisobutyrate, 2-carbamoylazaisobutyronitrile; containing radical emulsifying compounds having a peroxide group A redox system in which a reducing agent such as a radical emulsifier, sodium hydrogen sulfite, and ferrous sulfate is combined; Moreover, when using an emulsifier, 1 or more types selected from the group which consists of a well-known anionic emulsifier, a nonionic emulsifier, and an amphoteric emulsifier can be used as this emulsifier. In addition, you may use the reactive emulsifier etc. which have an unsaturated double bond in a molecule | numerator.

  There is no restriction | limiting in particular in the molecular weight modifier used for seed emulsion polymerization. Specific examples of molecular weight regulators include n-hexyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-hexadecyl mercaptan, n-tetradecyl mercaptan, t-tetradecyl mercaptan, thioglycolic acid Mercaptans such as dimethyl xanthogen disulfide, diethyl xanthogen disulfide, diisopropyl xanthogen disulfide, etc .; Xanthogen disulfides such as tetramethyl thiuram disulfide, tetraethyl thiuram disulfide, tetrabutyl thiuram disulfide; chloroform, carbon tetrachloride, tetrabromide Halogenated hydrocarbons such as carbon and ethylene bromide; hydrocarbons such as pentaphenylethane and α-methylstyrene dimer; Kurorein, methacrolein, allyl alcohol, 2-ethylhexyl thioglycolate, terpinolene, alpha-Terunepin, .gamma. Terunepin can include dipentene, 1,1-diphenylethylene and the like. These molecular weight regulators can be used singly or in combination of two or more. Of these, mercaptans, xanthogen disulfides, thiuram disulfides, 1,1-diphenylethylene, α-methylstyrene dimer and the like are more preferably used.

  The polymer particles (a) obtained as described above are usually spherical particles. The number average particle diameter of the polymer particles (a) is preferably 0.1 to 7 μm, and more preferably 0.1 to 5 μm. When the number average particle diameter of the polymer particles (a) is outside this range, the polymerization stability may be deteriorated.

  The polymer particles of the composition for optical materials of the present invention absorb the polymerizable monomer in the first emulsion polymerized particles (polymer particles (a)), and further seed in the presence of the second radical polymerization initiator. The second emulsion polymerized particles obtained by emulsion polymerization (hereinafter may be referred to as “polymer particles (b)”) are preferred.

  That is, polymer particles (b) can be produced by seed polymerizing a polymerizable monomer for forming polymer particles (b) in a state where the obtained polymer particles (a) are used as seed polymer particles. . For example, the polymerizable monomer or a pre-emulsion thereof may be dropped all at once, continuously, or continuously into an aqueous medium in which the polymer particles (a) are dispersed. The amount of the polymer particles (a) used at this time is preferably 1 to 100% by mass and more preferably 2 to 80% by mass with respect to 100% by mass of the polymerizable monomer. The second radical polymerization initiator may be the same as or different from that used in the production of the polymer particles (a), and when an emulsifier is used in the seed polymerization. May be the same as or different from that used in the production of the polymer particles (a). The conditions such as the polymerization time may be the same as in the production of the polymer particles (a). The polymer particles (b) obtained as described above are usually spherical particles.

[1-3] Binder component:
The composition for optical materials of the present invention contains a binder component. If this binder component is transparent having high transparency to visible light and can disperse and integrate the polymer particles on the surface of a resin sheet, for example, the type of the binder component is particularly It is not limited. The term “transparency” conceptually includes colored transparency and translucency in addition to colorless transparency.

  The binder component preferably has a light transmittance of 80% or more at a wavelength of 550 nm when a sheet having a thickness of 200 μm is formed from the binder component. If it does in this way, the light transmittance of the optical material molding formed with the composition for optical materials of this invention can be made more excellent. The light transmittance is more preferably 85% or more, and particularly preferably 90% or more. In consideration of the use environment, storage environment, and the like, the glass transition temperature of the binder component is preferably 100 ° C. or higher, more preferably 120 ° C. or higher, and particularly preferably 150 ° C. or higher.

  Specific examples of the binder component include thermoplastic resins such as polyvinyl acetate, polyvinyl alcohol, polyvinyl chloride, polyvinyl butyral, poly (meth) acrylate, and nitrocellulose; phenol resin, melamine resin, polyester resin, polyurethane resin, Examples thereof include thermosetting resins such as epoxy resins, and ionizing radiation curable resins that are cured by electron beam or ultraviolet irradiation. Among these, ionizing radiation curable resins are preferable in terms of workability.

  The content of the binder component is preferably 1 to 10000 parts by mass, more preferably 2 to 8000 parts by mass, and 3 to 5000 parts by mass with respect to 100 parts by mass of the polymer particles. Particularly preferred. When the content ratio of the binder component is less than 1 part by mass, for example, it tends to be difficult to disperse and integrate the polymer particles on the surface of a resin sheet or the like. On the other hand, when the content ratio of the binder component is more than 10,000 parts by mass, the optical properties of the optical material molded product or the antiglare film produced using this composition for optical materials, particularly, the antiglare property tends to be difficult to improve. is there.

[1-4] Other components:
In addition to the polymer particles and the binder component, the composition for optical materials of the present invention may contain other components such as a curing agent, a dispersant, and a dye as necessary.

  The content of other components is preferably 0 to 10 parts by mass, more preferably 0 to 5 parts by mass, and 0 to 3 parts by mass with respect to 100 parts by mass in total of the polymer particles and the binder component. It is particularly preferred that

[1-5] Method for producing composition for optical material:
The method for producing the composition for optical materials of the present invention is a step of removing the solvent from the emulsion containing the polymer particles and the solvent described above to obtain dry polymer particles (hereinafter referred to as “step (1)”). And a step of mixing the obtained polymer particles and a binder component (hereinafter may be referred to as “step (2)”).

  In the step (1), the method for removing the solvent from the emulsion is not particularly limited, but the freeze-drying method or the spray-drying method is preferable because it can be easily dried.

  In addition, it is preferable to dry until a solvent becomes a content rate of 5.0 mass% or less with respect to 100 mass% of said emulsion, and it is still more preferable to dry until it becomes 3.0 mass% or less. When the content ratio of the solvent is more than 5.0% by mass, the dispersibility in the binder component is lowered, and it may be difficult to produce a molded product exhibiting uniform optical characteristics.

  Subsequently, in the said process (2), the composition for optical materials of this invention can be obtained by mixing a polymer particle, a binder component, and the above-mentioned other component added as needed. In addition, you may add and mix the said other component, after mixing a polymer particle and a binder component. Although it does not specifically limit about the mixing method, For example, it can carry out using various kneading machines, bead mill, a high-pressure homogenizer, etc.

[2] Optical material molded product:
The optical material molded article of the present invention is composed of the above-described optical material composition. With such a configuration, an optical material molded article having excellent antiglare properties can be obtained. Accordingly, the optical material molded article of the present invention is suitable as an antiglare film, a light diffusing film, a light diffusing plate, a polarizing plate, a light guide plate or the like, taking advantage of the above characteristics.

  The optical material molded product of the present invention is formed by, for example, supplying a resin component and polymer particles to an extruder to form a master batch, then supplying the master batch to the extruder and injecting it into a cavity. The method of processing etc. can be mentioned.

[3] Antiglare film:
The antiglare film of the present invention comprises a base material layer and an antiglare layer formed on the at least one surface of the base material layer and made of the above-described composition for optical materials. With such a configuration, an antiglare film having excellent antiglare properties can be obtained.

  The base material layer constituting the antiglare film of the present invention is preferably a layer made of a transparent (colorless, transparent, colored, or translucent) resin. Specific examples of the resin constituting the base material layer include the same resin components as those contained in the resin material constituting the optical material molded article described above.

  The antiglare layer formed on at least one surface of the base material layer is a layer made of the composition for optical materials. The polymer particles contained in the optical material composition are highly crosslinked as described above, the number average particle diameter is 0.1 to 20 μm, and the variation coefficient of the particle diameter distribution is 20% or less. There is something. Further, as described above, the polymer particles are preferably produced by seed emulsion polymerization using a polymerizable monomer containing 5% by mass or more of a crosslinkable monomer, and more preferably, the seed emulsion polymerization is performed. It is manufactured by performing it twice or more. The antiglare film of the present invention containing such polymer particles has an advantage of having an excellent antiglare effect.

  By the way, since the polymer particle contained in the conventional anti-glare film can be manufactured without an advanced polymerization technique and equipment, it has been manufactured by a suspension polymerization method. However, when polymer particles are produced by this suspension polymerization method, the variation coefficient of the particle size distribution of the obtained polymer particles is large, that is, the particle size distribution (particle size distribution) becomes very wide, and the quality of the polymer particles is not uniform. It was. Then, there is a possibility that a film having sufficient antiglare property cannot be obtained due to non-uniform quality. The polymer particles produced by the suspension polymerization method can be classified with a sieve or the like to adjust the particle size distribution, but in this case, the production efficiency tends to deteriorate.

  In the antiglare film of the present invention, the polymer particles contained in the optical material composition are integrated on the base material layer by the binder component contained in the optical material composition. Some of the polymer particles may be in a state in which a part of the polymer particles protrudes from the surface of the binder component. Further, the protruding part of the polymer particles may be entirely covered with the binder component or may be only partially covered. Note that all of the polymer particles may be completely buried in the binder component.

  The antiglare film of the present invention is produced, for example, by dispersing or dissolving polymer particles and a binder component in an organic solvent in which they can be dispersed or dissolved to form a slurry, coating with various coaters, and drying. can do. Specific examples of the organic solvent include water, toluene, cyclohexane, cyclohexanone, methyl isobutyl ketone (MIBK), methyl ethyl ketone (MEK), N-methyl-2-pyrrolidone (NMP) and the like.

  The content ratio of the organic solvent is preferably 10 to 2000 parts by mass, and more preferably 20 to 1000 parts by mass with respect to 100 parts by mass in total of the polymer particles and the binder component.

  Although the thickness of a base material layer is not specifically limited, Usually, 0.03-0.3 mm, Preferably it is about 0.05-0.2 mm. Moreover, although it does not specifically limit about the thickness of an anti-glare layer, Usually, 0.005-0.1 mm, Preferably it is about 0.008-0.08 mm.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. In the examples and comparative examples, “parts” and “%” are based on mass unless otherwise specified. Moreover, the measuring method of various physical-property values and the evaluation method of various characteristics are shown below.

[Number average particle diameter]:
In order to measure the number average particle size of the polymer particles, a laser particle size analysis system (trade name “LS13320”) manufactured by Beckman Coulter, Inc. was used. In Table 1, “particle diameter (μm)” indicates this evaluation.

[Coefficient of variation of particle size distribution (CV value)]:
In order to measure the coefficient of variation of the particle size distribution of the polymer particles, a laser particle size analysis system (trade name “LS13320”) manufactured by Beckman Coulter, Inc. was used. In Table 1, “CV value (%)” indicates this evaluation.

[10% thermal weight loss temperature]:
As an indicator that the polymer particles are highly crosslinked, the temperature when the polymer particles were reduced by a predetermined amount was measured. Specifically, when a thermogravimetric analyzer DTG-60A manufactured by Shimadzu Corporation is used and 10 mg of polymer particles are heated at a rate of 20 ° C./min in a nitrogen atmosphere, 10 of 10% of the initial mass (10 mg) of the polymer particles. The temperature (° C.) when the mass% was reduced was measured (thermogravimetric analysis). According to the thermogravimetric analysis, the higher the polymer particle is highly crosslinked, the higher the temperature at which the mass of the polymer particle is reduced by 10% by mass. In Table 1, “10% thermal weight loss temperature (° C.)” indicates this evaluation.

[Toluene soluble content]:
In order to measure the soluble content of the polymer particles in toluene, 200 mg of polymer powder obtained as described below was added to 100 ml of toluene and stirred at room temperature for 24 hours. Thereafter, the mixture is further allowed to stand for 24 hours, the supernatant is collected, the supernatant liquid is dried, the mass of the remaining solid is measured, and all the solid (polymer particles) remaining in the toluene before being immersed in toluene is measured. The toluene soluble content of the polymer particles was calculated as a mass ratio with respect to the solid content (polymer particles). In Table 1, “Toluene soluble content (%)” indicates this evaluation.

  [Haze (%)]: A film-shaped optical material molded product (hereinafter sometimes referred to as “film”) was produced, and haze was measured in order to evaluate the degree of deterioration of the film. This measurement was performed according to JIS K7105 using a haze meter manufactured by Suga Test Instruments Co., Ltd. In Table 2, “Haze (%)” indicates this evaluation.

[Prevention of glare]: A film was prepared in the same manner as in the evaluation of haze, and the reflection of light from the fluorescent lamp (glare) in this film was evaluated. This evaluation was confirmed visually. Evaluation criteria were as follows. In Table 2, “Prevention of glare” indicates this evaluation.
◎: Almost no glare ○: Little glare △: There is glare ×: Large glare

[Synthesis of polymer particles]:
(Synthesis Example 1)
15 parts of monodispersed particles (hereinafter sometimes referred to as “monodispersed polystyrene particles”) made of polystyrene having a number average particle diameter of 0.4 μm and a weight average molecular weight of 10,000 are used as seeds, and styrene (in Table 1) Add 80 parts of “ST”) and 20 parts of divinylbenzene (shown as “DVB” in Table 1) as a crosslinkable monomer, and slowly stir at 40 ° C. for 3 hours to add monomer components (styrene and divinylbenzene). Absorbed in the monodisperse polystyrene particles. Thereafter, the temperature is raised to 75 ° C., and a polymer reaction (seed emulsion polymerization) is performed for 3 hours in the presence of potassium persulfate (manufactured by Asahi Denka Kogyo Co., Ltd.) as a radical polymerization initiator, whereby polymer particles (a) are obtained. An emulsion containing was obtained. The number average particle diameter of the polymer particles (a) in the emulsion was 2.0 μm, and almost no coagulum was generated.

  Next, 15 parts of the emulsion containing the polymer particles (a) (but as solid content) is used as a seed, 80 parts of styrene and 20 parts of divinylbenzene are added, and the mixture is slowly stirred at 40 ° C. for 3 hours. (Styrene and divinylbenzene) were absorbed in the polymer particles (a). At that time, 5 parts of acetone was added as a seed swelling aid to facilitate the absorption of the monomer component into the seed. Thereafter, the temperature is raised to 75 ° C., and polymer particles (b) (hereinafter referred to as “polymer (I)”) are obtained by performing a polymerization reaction (seed emulsion polymerization) for 3 hours in the presence of the radical polymerization initiator. There was obtained an emulsion containing The polymer particles (b) in this emulsion have a number average particle size of 2.8 μm, a CV value of 14%, a toluene soluble content of 0.4, a 10% thermal weight loss temperature of 390 ° C., It hardly occurred.

(Synthesis Examples 2 to 8)
Except making it the compounding prescription shown in Table 1, it contains polymer (II)-(VIII) (namely, polymer particle (a) or polymer particle (b) mentioned above) similarly to the synthesis example 1, respectively. An emulsion was obtained. Table 1 shows various physical property values of the polymer particles. The polymers (V) and (VI) of Synthesis Examples 5 and 6 are composed of polymer particles (a), and the polymers other than Synthesis Examples 5 and 6 are composed of polymer particles (b). In Table 1, “TMPMA” represents trimethylolpropane trimethacrylate, and “MMA” represents methyl methacrylate.

  It can be confirmed that the polymer particles of Synthesis Examples 2 to 6 are highly crosslinked, have a number average particle diameter of 0.1 to 20 μm, and have a coefficient of variation (CV value) of particle diameter distribution of 20% or less. It was. Moreover, it has confirmed that the 10% thermogravimetric reduction temperature of the said polymer was 335 degreeC-390 degreeC, and toluene soluble content was 0.4%-0.5%.

  Since the polymer particles of Synthesis Example 7 have a large amount of monodisperse polystyrene particles, the number average particle diameter is 0.08, and it was confirmed that a sufficient number average particle diameter could not be obtained. Moreover, since the content of the crosslinking monomer contained in the polymerizable monomer in the polymer particle of Synthesis Example 8 was less than the lower limit (5% by mass), it was confirmed that a highly crosslinked polymer could not be obtained. It was also confirmed that the 10% thermal weight loss temperature was 310 ° C. and the toluene soluble content was 36.9%.

(Synthesis Example 9)
Polymer particles (polymer IX) having a number average particle diameter of 3.5 μm were obtained by suspension polymerization, that is, not seed emulsion polymerization. Since the polymer particles of Synthesis Example 9 were produced by a suspension polymerization method, the CV value was 40%, and it was confirmed that the particle size distribution was in a wide range.

[Preparation of optical material composition and production of optical material molded article]:
(Example 1)
First, the emulsion containing the polymer (I) obtained by the synthesis of the polymer particles described above is dried using a spray dryer (model number “L-8 type”, manufactured by Okawara Chemical Co., Ltd.), Polymer (I) was obtained.

  Next, 90 parts of a hexafunctional acrylate monomer (trade name “NK Ester A-DPH”, manufactured by Shin-Nakamura Chemical Co., Ltd., shown as “DPHA” in Table 2) as a binder component, and a photoinitiator (trade name “IRGACURE 184”) Made by Ciba Specialty Chemicals Co., Ltd., 3 parts shown in Table 2 as “photoinitiator”, 7 parts of the above powdered polymer (I), and 100 parts of toluene (shown as “solvent” in Table 2) as a solvent The liquid was obtained and this liquid mixture was prepared as a composition for optical materials.

Next, the prepared composition for an optical material was coated on a polyethylene terephthalate (PET) substrate with a Mayer bar so that the thickness of the binder portion after curing was 10 μm. After drying, a film (optical material molded product) was obtained by curing by irradiating with ultraviolet light at 500 mJ / cm ² with a high-pressure mercury lamp. It was confirmed that the obtained film had a haze of 44% as an optical characteristic, an evaluation of glare prevention was “◎”, and exhibited a very good glare prevention effect.

(Examples 2-6, Comparative Examples 1 and 2)
A composition for optical material was prepared in the same manner as in Example 1 except that the formulation shown in Table 2 was used, and then a film was obtained. The film of Examples 2-6 showed the favorable glare prevention effect, and has confirmed that the balance of a haze and a glare prevention effect was very excellent.

  Especially, since the film of Examples 1-4 uses a polymer particle (b), that is, after obtaining the polymer particle (a), the polymer particle (a) is further used as a seed particle for seed emulsification. Since it contains polymer particles (b) obtained by polymerization, particles with less toluene solubles were obtained, and it was confirmed that the balance between haze and glare prevention effect was good. . This is presumably because the solvent resistance of the polymer particles is further improved by the two-stage crosslinking (two seed polymerizations), and the shape of the particles is kept good in the molded optical material. .

  In addition, since the films of Examples 1, 2, and 4 use an aromatic vinyl-based monomer as a crosslinkable monomer, the evaluation of glare prevention is “◎” and shows a better glare prevention effect. Was confirmed. It was also confirmed that the balance between haze and glare prevention effect was very excellent.

  In the film of Comparative Example 1, since the particle size of the polymer (VII) used was too small, it was confirmed that a sufficient light scattering effect could not be obtained and the glare prevention effect was reduced. Moreover, since the film of the comparative example 2 has too few compounding quantities of a crosslinkable monomer, the polymer particle (polymer (VIII)) to be used cannot show sufficient solvent resistance. Therefore, since it became impossible to maintain a good particle shape in the composition for optical materials, it was confirmed that a sufficient light scattering effect could not be obtained and the glare prevention effect was lowered.

(Comparative Example 3)
A film was produced in the same manner as in Example 1 using the polymer particles of Synthesis Example 9, that is, the polymer particles (polymer IX) obtained by the suspension polymerization method. Although this film showed substantially the same value even when compared with the films of Examples 1 to 6 and Comparative Examples 1 and 2, the evaluation of glare prevention was “Δ”, and the glare prevention effect was inferior. I was able to confirm. This is because polymer particles (polymer IX) obtained by suspension polymerization have a very wide particle size distribution, that is, components having various particle diameters such as microparticle components and macroparticle components are mixed. This is probably because the scattering characteristics are not uniform.

  The optical material molded article of the present invention is suitable as an antiglare film, a light diffusion film, a light diffusion plate, a polarizing plate, or a light guide plate.

Claims (9)

Polymer particles that are highly crosslinked, have a number average particle size of 0.1 to 20 μm, and a coefficient of variation (CV value) of particle size distribution of 20% or less;
A binder component;
A composition for optical materials.   The composition for optical materials according to claim 1, wherein the polymer particles include a structural unit derived from an aromatic vinyl monomer or a structural unit derived from an acrylic acid monomer. 3. The composition for optical materials according to claim 1, wherein the polymer particles have a 10% weight loss temperature (T ₁₀ ) of 320 ° C. or more by thermogravimetric analysis and a soluble content in toluene of 10% or less. . The polymer particles are
A first emulsion polymerization obtained by absorbing a polymerizable monomer containing 5% by mass or more of a crosslinkable monomer in monodisperse particles of a styrene-based polymer, and subjecting it to seed emulsion polymerization in the presence of a first radical polymerization initiator. It is a particle | grain, The composition for optical materials as described in any one of Claims 1-3. The polymer particles are
A first emulsion polymerization obtained by absorbing a polymerizable monomer containing 5% by mass or more of a crosslinkable monomer in monodisperse particles of a styrene-based polymer, and subjecting it to seed emulsion polymerization in the presence of a first radical polymerization initiator. Particles
The second emulsion-polymerized particle obtained by absorbing the polymerizable monomer and further subjecting the emulsion to seed emulsion polymerization in the presence of a second radical polymerization initiator. Composition for optical material. Removing the solvent from an emulsion containing polymer particles and a solvent that is highly crosslinked, has a number average particle size of 0.1 to 20 μm, and a variation coefficient (CV value) of particle size distribution of 20% or less, Obtaining the polymer particles in a dry state;
Mixing the obtained polymer particles and a binder component;
The manufacturing method of the composition for optical materials which has these.   The optical material molded article which consists of a composition for optical materials as described in any one of Claims 1-5.   The optical material molded article according to claim 7, which is an antiglare film, a light diffusion film, a light diffusion plate, a polarizing plate, or a light guide plate. A base material layer;
An antiglare film comprising: an antiglare layer comprising the composition for optical materials according to any one of claims 1 to 5 formed on at least one surface of the base material layer.