JPWO2008123517A1 - Amorphous particles, irregularly shaped particle composition and method for producing the same, and light diffusion molded article - Google Patents

Abstract

It is possible to provide a molded article for an optical material having an excellent balance between light transmittance and light diffusibility, and is disposed on at least a part of the surface of the (X) particles made of the first polymer and the (X) particles. And (Z) particles made of the second polymer, and the number-average particle diameter is 0.3 to 8 μm. In addition, it is possible to provide a molded article for an optical material that suppresses regular reflection light on the surface, is excellent in light diffusibility, and is also excellent in linear transmittance, and is composed of a third polymer (Y) hollow particles, (Y) (Z) particles made of a fourth polymer disposed on at least a part of the surface of the hollow particles, and the number-average particle diameter is 0.4 to 10 μm .

Description

  The present invention relates to an irregularly shaped particle, an irregularly shaped particle composition and a production method thereof that can provide a light diffusion molded article having excellent light diffusibility and the like, and a light diffusion molded article having excellent light diffusibility and the like.

  Currently, liquid crystal display devices are used as display devices for televisions, personal computers, and the like. The liquid crystal display device includes a light source, a light guide plate disposed and irradiated in the vicinity of the light source, a light diffusion plate, a prism sheet, and a liquid crystal display panel sequentially disposed in front of the light guide plate. Yes. The light diffusing plate disposed in front of the light guide plate is used for more uniformly diffusing the light that has passed through the light guide plate. Attempts have been made to improve the luminance of the liquid crystal display device by improving the characteristics of the light diffusion plate.

  As a related art, a light diffusion plate using light diffusing resin particles in which an average particle diameter and a coefficient of variation (CV value) of particle diameter distribution are set within a predetermined range is disclosed (for example, patent document). 1).

  However, even when the light diffusing plate using the light diffusing resin particles described in Patent Document 1 is used, it cannot be said that the brightness of the liquid crystal display device is sufficiently improved, and further improvement is desired. It was rare. Specifically, there has been a demand for the development of a light diffusing plate having good light transmittance and light diffusibility and higher luminance. In order to satisfy such a demand, a light diffusion plate using synthetic resin particles having an average particle size and an average particle size distribution set within a predetermined range is disclosed (for example, see Patent Document 2).

  In addition, in the above liquid crystal display device, when transmitted light or reflected light is not properly diffused on the surface, it looks very dazzling when viewed from the front, or light from the surrounding environment such as a fluorescent lamp is reflected as it is. There is a problem that the image is reflected by doing so (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 3). The film described in Patent Document 3 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-7-234304 JP 2004-226604 A JP-A-8-30991

  However, even the light diffusing plate using synthetic resin particles described in Patent Document 2 still has room for improvement in light transmittance and light diffusibility, and a light diffusing molded article with further high characteristics. And development of a material capable of producing such a light diffusion molded article has been desired. Moreover, even if it is an anti-glare film using the synthetic resin particle described in Patent Document 3, there is still room for improvement in the anti-glare property, and a material capable of producing an anti-glare film having further high characteristics. Development was desired.

  The present invention has been made in view of such problems of the prior art, and the problem is that the regular reflection light on the surface is suppressed, the light diffusibility is excellent, and the straight transmittance is also achieved. An irregularly shaped particle, an irregularly shaped particle composition and a method for producing the same, which can provide an excellent molded article for an optical material that has an excellent balance between light transmission and light diffusibility, and a light that suppresses regular reflection light on the surface. An object of the present invention is to provide a molded article for an optical material which has excellent diffusibility and excellent linear transmittance, that is, excellent balance between light transmittance and light diffusibility. Also, irregularly shaped particles capable of providing a molded article for an optical material having an excellent balance between light transmittance and light diffusibility, an irregularly shaped particle composition and a method for producing the same, and an optical material having a balance between light transmittance and light diffusibility The object is to provide a molded article for a material.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have achieved the above-mentioned problems by using irregularly shaped particles that are composed of two or more particles and whose number average particle diameter is within a predetermined numerical range. As a result, the present invention has been completed.

  That is, according to the present invention, the following irregularly shaped particles, irregularly shaped particle compositions and production methods thereof, and molded articles for optical materials are provided.

[1] (X) particles made of a first polymer, and (Z) particles made of a second polymer disposed on at least part of the surface of the (X) particles, A deformed particle having a number average particle diameter of 0.3 to 8 μm (hereinafter sometimes referred to as “first deformed particle”).

[2] The (X) and the number average particle diameter of the particles _{(L a),} the value of the ratio of the (Z) the number-average particle diameter of the particles _{(L b) is, (L a) / (L} b) = The irregular shaped particle according to [1], which is 0.05 to 20.0.

[3] The above [1], wherein both the first polymer and the second polymer contain (m1) an aromatic vinyl monomer unit and (m3) other monomer units. Or the irregularly shaped particle according to [2].

[4] The deformed particle according to any one of [1] to [3], wherein the first polymer further contains (m2) a polar functional group-containing monomer unit.

[5] The irregularly shaped particle according to any one of [1] to [4], wherein the (X) particle is a seed polymer particle, and the (Z) particle is formed by seed polymerization.

[6] (A-1) An irregularly shaped particle composition (hereinafter referred to as “first irregularly shaped particle composition”) comprising the irregularly shaped particles according to any one of [1] to [5] and (B) a binder component. ").

[7] A step of removing the solvent from the emulsion containing the deformed particles according to any one of [1] to [5] to obtain the dried deformed particles, and the obtained deformed particles and a binder component. And a method for producing a deformed particle composition.

[8] Optical material molded article (hereinafter referred to as “first optical material molded article”) made of a resin material containing a resin component and the irregularly shaped particles according to any one of [1] to [5]. Sometimes).

[9] The optical material molded article according to [8], which is a light guide plate, a light diffusing plate, a light diffusing film, an antiglare film, a prism sheet, or a protect sheet.

[10] An optical material molded article comprising: a base material layer; and a light diffusion layer formed on at least one surface of the base material layer and made of the irregularly shaped particle composition according to [6]. , Sometimes referred to as “second molded article for optical material”).

[11] The optical material molded article according to [10], which is a light diffusing plate, a light diffusing film, an antiglare film, a prism sheet, or a protect sheet.

[12] (Y) hollow particles made of a third polymer, and (Z) particles made of a fourth polymer disposed on at least a part of the surface of the (Y) hollow particles. , Irregular shaped particles having a number average particle size of 0.4 to 10 μm (hereinafter sometimes referred to as “second irregular shaped particles”).

[13] The (Y) to the number average particle diameter of the hollow particles _{(L a),} the value of the ratio of the (Z) the number-average particle diameter of the particles _{(L b) is, (L a) / (L} b) = Deformed particles according to [12], wherein 0.05 to 20.0.

[14] The third polymer comprises 60 to 98% by mass of a structural unit derived from (a1) an aromatic vinyl monomer, and (a2) 2 to 40 structural units derived from a polar functional group-containing monomer. The deformed particle according to [12] or [13], containing 0% to 30% by mass of a constituent unit derived from mass% and (a3) another monomer unit.

[15] The fourth polymer is at least one selected from the group consisting of (b1) a structural unit derived from an aromatic vinyl monomer and (b2) a structural unit derived from a (meth) acrylate compound. The deformed particle according to any one of the above [12] to [14].

[16] The deformed particle according to any one of [12] to [15], wherein the (Y) hollow particle is a seed polymer particle, and the (Z) particle is formed by seed polymerization.

[17] A deformed particle composition made of a resin material containing a resin component and the deformed particles according to any one of [12] to [16] (hereinafter referred to as “second deformed particle composition”) There is).

[18] A molded article for an optical material made of a resin material containing a resin component and the irregularly shaped particles according to any one of [12] to [16] (hereinafter, “third molded article for an optical material”) May be noted).

[19] A molded article for an optical material comprising: a base material layer; and an optical material layer formed on at least one surface of the base material layer and made of the irregularly shaped particle composition according to [18]. Hereinafter, it may be referred to as “fourth molded article for optical material”.

[20] The molded article for an optical material according to [19], which is a light guide plate, a light diffusing plate, a light diffusing film, an antiglare film, a prism sheet, or a protect sheet.

  The first deformed particles of the present invention are (X) particles made of the first polymer, and (Z) particles made of the second polymer arranged on at least a part of the surface of the (X) particles. And the number average particle diameter thereof is 0.3 to 8 μm, so that regular reflection light on the surface is suppressed, light diffusibility is excellent, and linear transmittance is also excellent. It is possible to provide a molded article for an optical material having an excellent balance between the property and the light diffusibility.

  The second modified particles of the present invention comprise (Y) hollow particles comprising a third polymer and a fourth polymer disposed on at least part of the surface of the (Y) hollow particles. (Z) particles, and the number average particle diameter thereof is 0.4 to 10 μm, so that it is possible to provide a molded article for an optical material having an excellent balance between light transmittance and light diffusibility. It plays.

  Since the first irregularly shaped particle composition of the present invention contains the first irregularly shaped particles and (B) the binder component, the regular reflection light on the surface is suppressed, the light diffusibility is excellent, and the straight transmission rate. In addition, there is an effect that it is possible to provide a molded article for an optical material that is excellent in the light transmittance and light diffusibility.

  In addition, the second modified particle composition of the present invention provides a molded article for an optical material having a good balance between light transmittance and light diffusibility, comprising a resin material containing a resin component and second modified particles. There is an effect that it is possible.

  The method for producing the deformed particle composition of the present invention comprises a step of removing the solvent from the emulsion containing the first deformed particles to obtain the deformed particles in a dry state, and the obtained deformed particles and the binder component are mixed. Therefore, it is possible to produce an irregularly shaped particle composition capable of providing a molded article for an optical material having an excellent balance between light transmittance and light diffusibility.

  Since the first molded article for an optical material of the present invention is composed of a resin material containing a resin component and first irregularly shaped particles, the regular reflection light on the surface is suppressed, and the light diffusibility is excellent. In addition, it also has an effect of being excellent in straight transmittance, that is, excellent in balance between light transmittance and light diffusibility.

  A second molded article for an optical material according to the present invention includes a base material layer and a light diffusion layer formed on at least one surface of the base material layer and made of the first deformed particle composition. Therefore, it has the effect of suppressing regular reflection light on the surface, excellent in light diffusibility, and excellent in straight transmittance, that is, excellent in balance between light transmittance and light diffusibility. It is.

  The third molded article for an optical material according to the present invention is made of a resin material containing a resin component and second irregularly shaped particles, and therefore has an effect of excellent balance between light transmittance and light diffusibility. It plays.

  A fourth molded article for an optical material according to the present invention includes a base material layer and a light diffusion layer formed on at least one surface of the base material layer and made of the second deformed particle composition. Therefore, the effect of excellent balance between light transmittance and light diffusibility is achieved.

It is a schematic diagram which shows one Embodiment of the 1st irregular shape particle | grains of this invention. It is a schematic diagram which shows other embodiment of the 1st irregular shape particle | grains of this invention. It is a schematic diagram which shows other embodiment of the 1st irregular shape particle | grains of this invention. It is a schematic diagram which shows other embodiment of the 1st irregular shape particle | grains of this invention. It is a schematic diagram which shows other embodiment of the 1st irregular shape particle | grains of this invention. It is a schematic diagram which shows other embodiment of the 1st irregular shape particle | grains of this invention. It is a schematic diagram explaining the major axis and minor axis of the first irregularly shaped particles. It is a schematic diagram which shows the initial stage of a mode that the (Z) particle | grains in a 1st deformed particle grow. It is a schematic diagram which shows the intermediate | middle stage of a mode that (Z) particle | grains in a 1st deformed particle grow. It is a schematic diagram which shows the last stage of a mode that (Z) particle | grains in a 1st deformed particle grow.

Explanation of symbols

1: (X) particles, 2: (Z) particles, D: minor axis, L: major axis.

  BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described below, but the present invention is not limited to the following embodiment, and is based on the ordinary knowledge of those skilled in the art without departing from the gist of the present invention. It should be understood that modifications and improvements as appropriate to the following embodiments also fall within the scope of the present invention.

[1] First deformed particle:
One embodiment of the first deformed particle of the present invention is an (X) particle comprising the first polymer and a second polymer disposed on at least a part of the surface of the (X) particle. (Z) particles, and the number average particle diameter thereof is 0.3 to 8 μm. Such first irregular shaped particles can provide a molded article for an optical material having an excellent balance between light transmittance and light diffusibility.

[1-1] (X) Particles:
(X) particle | grains which comprise the 1st irregular shape particle | grain of this embodiment consist of a 1st polymer. This first polymer is preferably seed polymer particles capable of absorbing an oil-soluble polymerization initiator containing an organic compound having a water solubility of ^10-2 % by mass or less. Specifically, aromatic vinyl compound particles such as a styrene polymer, a styrene-butadiene copolymer, and a styrene- (meth) acrylic acid ester copolymer are preferable.

[1-2] (Z) Particles:
The (Z) particles constituting the first deformed particles of the present embodiment are composed of a second polymer disposed on at least a part of the surface of the (X) particles.

Constituent units contained in the first polymer and the second polymer:
In the first polymer and the second polymer, for example, (m1) an aromatic vinyl monomer unit (hereinafter also referred to as “structural unit (m1)”) and (m3) It preferably contains other monomer units (hereinafter also referred to as “structural unit (m3)”).

((M1) aromatic vinyl monomer unit):
Examples of the aromatic vinyl monomer used for constituting the structural unit (m1) include styrene, α-methylstyrene, vinyltoluene, p-methylstyrene, 2-methylstyrene, 3-methylstyrene, and 4-methyl. Styrene, 4-ethylstyrene, 4-tert-butylstyrene, 3,4-dimethylstyrene, 4-methoxystyrene, 4-ethoxystyrene, 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 2,4- Examples include 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.

((M3) Other monomer units):
The first polymer may contain a monomer unit (also referred to as a structural unit (m3)) composed of other monomers copolymerizable with the above-mentioned various monomers, if necessary. Good. Examples of other monomers constituting the structural unit (m3) include N-methylol unsaturated carboxylic acid amides such as N-methylol (meth) acrylamide and N, N-dimethylol (meth) acrylamide; 2 -Aminoalkyl group-containing acrylamides such as dimethylaminoethylacrylamide; unsaturated carboxylic acids such as (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N, N-ethylenebis (meth) acrylamide, maleic acid amide, maleimide Amides or imides; N-monoalkyl (meth) acrylamides such as N-methylacrylamide and N, N-dimethylacrylamide; N, N-dialkylacrylamides; Aminoalkyl such as 2-dimethylaminoethyl (meth) acrylate Group-containing (meth) a Relates; aminoalkoxyalkyl group-containing (meth) acrylates such as 2- (dimethylaminoethoxy) ethyl (meth) acrylate; vinyl halide compounds such as vinyl chloride, vinylidene chloride and fatty acid vinyl esters; Conjugated diene compounds such as butadiene, 2-methyl-1,3-butadiene, 2-chloro-1,3-butadiene, 2,3-dimethyl-1,3-butadiene,

  (Cyclo) such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, etc. ) Alkyl (meth) acrylates; Alkoxy (cyclo) alkyl (meth) acrylates such as 2-methoxyethyl (meth) acrylate and p-methoxycyclohexyl (meth) acrylate; Multivalents such as trimethylolpropane tri (meth) acrylate (Meth) acrylates; ester group-containing compounds such as vinyl esters such as vinyl acetate, vinyl propionate and vinyl versatate.

Ratio of structural units (m1) and (m3):
The proportion of the structural unit (m1) contained in the first polymer is preferably 60 to 98% by mass when the total of all the structural units contained in the first polymer is 100% by mass, It is more preferable that it is 65-95 mass%, and it is especially preferable that it is 70-90 mass%. If the proportion of the structural unit (m1) contained in the first polymer is less than 60% by mass, it tends to be difficult to obtain sufficient light diffusibility, whereas if it exceeds 98% by mass, irregular shaped particles Tend to be difficult to obtain.

  The proportion of the structural unit (m3) contained in the first polymer is preferably 0 to 40% by mass when the total of all the structural units contained in the first polymer is 100% by mass, It is more preferable that it is 0-30 mass%, and it is especially preferable that it is 0-20 mass%. When the proportion of the structural unit (m3) contained in the first polymer is more than 40% by mass, sufficient light diffusibility tends to be hardly obtained.

  The proportion of the structural unit (m1) contained in the second polymer is preferably 60 to 100% by mass when the total of all the structural units contained in the second polymer is 100% by mass, It is more preferable that it is 65-95 mass%, and it is especially preferable that it is 70-90 mass%. When the proportion of the structural unit (m1) contained in the second polymer is less than 60% by mass, sufficient light diffusibility tends to be hardly obtained.

  The proportion of the structural unit (m3) contained in the second polymer is preferably 0 to 40% by mass when the total of all the structural units contained in the second polymer is 100% by mass, It is more preferable that it is 0-30 mass%, and it is especially preferable that it is 0-20 mass%. When the proportion of the structural unit (m3) contained in the second polymer is more than 40% by mass, it tends to be difficult to obtain sufficient light diffusibility.

  In the first modified particles in the present invention, the composition of the first polymer and the composition of the second polymer may be the same or different, but the monomer contained in the first polymer It is also preferred that at least one of the units is different from the monomer unit contained in the second polymer. That is, in this case, at least one of the monomer units constituting the first irregularly shaped particle is contained only in one of the first polymer and the second polymer. become. With such a configuration, for example, (X) particles and (Z) particles can be asymmetrically separated. That is, irregularly shaped particles can be obtained as a whole in which at least some of the (X) particles and (Z) particles are in contact with each other.

(M2) Polar functional group-containing monomer unit:
The first polymer in the first deformed particle of the present invention includes (m2) a polar functional group-containing monomer unit (hereinafter also referred to as “structural unit (m2)”) in addition to the above structural unit. Is preferably included, and when the structural unit (m2) is included, it is easy to maintain good polymerization stability. The polar functional group-containing monomer is a monomer having a polar functional group in the molecule. Preferred examples of the polar functional group include a carboxyl group, a cyano group, a hydroxyl group, a glycidyl group, and an ester group. Specific examples of the polar functional group-containing monomer include (1) carboxyl group-containing monomer, (2) cyano group-containing monomer, (3) hydroxyl group-containing monomer, and (4) glycidyl group-containing monomer. And (5) an ester group-containing monomer. In addition, these monomers can be used individually by 1 type or in combination of 2 or more types.

(1) Carboxyl group-containing monomer:
(1) Examples of the carboxyl group-containing monomer include (meth) acrylic acid, crotonic acid, cinnamic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, monomethyl maleate, maleic acid Examples thereof include carboxyl group-containing unsaturated monomers such as monoethyl, monomethyl itaconate, monoethyl itaconate, and mono-2- (meth) acryloyloxyethyl hexahydrophthalate, and anhydrides thereof. Among these, (meth) acrylic acid is preferable.

(2) Cyano group-containing monomer:
(2) Examples of the cyano group-containing monomer include vinyl cyanide monomers such as (meth) acrylonitrile, crotonnitrile, and cinnamic acid nitrile; 2-cyanoethyl (meth) acrylate, 2-cyanopropyl (meth) ) Acrylate, 3-cyanopropyl (meth) acrylate, and the like. Among these, (meth) acrylonitrile is preferable.

(3) Hydroxyl-containing monomer:
(3) Examples of the hydroxyl group-containing monomer include hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxycyclohexyl (meth) acrylate, and neopentyl glycol. Hydroxy (cyclo) alkyl mono (meth) acrylates such as mono (meth) acrylate; substituted hydroxy (cyclo) such as 3-chloro-2-hydroxypropyl (meth) acrylate and 3-amino-2-hydroxypropyl (meth) acrylate ) Alkyl mono (meth) acrylates. Among these, hydroxymethyl (meth) acrylate is preferable.

(4) Glycidyl group-containing monomer:
(4) Examples of the glycidyl group-containing monomer include allyl glycidyl ether, glycidyl (meth) acrylate, methyl glycidyl methyl acrylate, epoxidized cyclohexyl (meth) acrylate, and the like. Among these, glycidyl (meth) acrylate is preferable.

(5) Ester group-containing monomer:
(5) Examples of the ester group-containing monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (tertiary) butyl (meth) acrylate, and n-hexyl (meth) acrylate. , 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, p-methoxycyclohexyl (meth) acrylate, trimethylolpropane tri (meth) acrylate, and the like. Among these, methyl (meth) acrylate and (tertiary) butyl (meth) acrylate are preferable.

Ratio of structural unit (m2):
When the first polymer contains the structural unit (m2), the proportion of the structural unit (m2) is 100% by mass of the total of the structural unit (m1), the structural unit (m2), and the structural unit (m3) below. In this case, it is preferably 2 to 40% by mass, more preferably 4 to 35% by mass, and particularly preferably 8 to 30% by mass. When the proportion of the structural unit (m2) contained in the first polymer is within the above range, the (X) particles and the (Z) particles can be easily separated asymmetrically. When the ratio is less than 2% by mass, particles having a shape intended in the present invention may not be obtained. On the other hand, if it exceeds 40% by mass, the light diffusibility tends to be inferior.

  As a reactive functional group, a polymer having an ester group, an amide group, an amine group, a carboxyl group, a glycidyl group, or a hydroxyl group is, for example, copolymerized with a monomer having these reactive functional groups, or It can be obtained by grafting a compound having these reactive functional groups. The polymer having a sulfonic acid group can be obtained, for example, by polymerizing a monomer in the presence of a reactive surfactant having a sulfonic acid group. Moreover, the polymer which has a sulfate group can be obtained by polymerizing a monomer using initiators, such as potassium persulfate, for example. When the amount of the reactive functional group contained in the first polymer and / or the second polymer is converted into the amount of the compound used for the introduction of the reactive functional group, the total amount of the respective polymers. The content is preferably 0.5 to 50% by mass, and more preferably 2 to 30% by mass.

shape:
The first deformed particles of the present embodiment have (X) particles and (Z) particles, and the (Z) particles are arranged on at least a part of the surface of the (X) particles. . Moreover, it is preferable that the (Z) particles are arranged in a protruding shape on at least a part of the surface of the (X) particles.

  Here, the “abnormal shape” in the present specification means a shape obtained by arranging one particle (for example, (X) particle) on at least a part of the surface of the other particle (for example, (Z) particle). More specifically, the center-to-center distance between the (X) particle and the (Z) particle in a cross section cut by a plane passing through the center of the (X) particle and the (Z) particle is (X ) A shape that is less than or equal to the sum of the particle radius and (Z) particle radius.

  In the deformed particle of this embodiment, the (X) particle and the (Z) particle are both present in a substantially single region and are asymmetrically arranged with respect to the center point of the deformed particle as a whole. It is preferable. In other words, unlike the conventional core-shell particle in which the core portion is not exposed on the particle surface, the deformed particle of this embodiment has both (X) particles and (Z) particles exposed on the surface. Is preferred. In other words, a shape in which (Z) particles are localized on the surface of (X) particles or a shape in which (X) particles are localized on the surface of (Z) particles is preferable. In addition, the overall shape of the irregularly shaped particles of the present embodiment is specifically a shape in which (X) particles and (Z) particles are at least partially in contact with each other or overlap each other, so-called snow dharma shape. (Or a pear shape, a cocoon shape, etc.) is preferable. It is also preferred that the so-called snow dharma-shaped constricted part is in a shape located at or near the center of the whole deformed particle. As a specific example of such a “deformed” particle, as shown in FIG. The shape can be mentioned.

  In addition, when the shape as a whole particle | grain is a spherical shape with a spherical protrusion like FIG. 1, when it is a spherical shape like FIGS. 2-4, when it is a rugby ball shape like FIG. Even in the case of a twin sphere like the above, it is included in the concept of “deformed particle” in the present specification.

Long diameter / short diameter ratio:
The first deformed particles of the present embodiment have a ratio value ((L) / (D)) of the number average value (L) of the major axis and the number average value (D) of the minor axis of 1.0. Is preferably 2.0, more preferably 1.1 to 1.9, and particularly preferably 1.2 to 1.8. When the value of (L) / (D) is more than 2.0, dispersibility in the binder component is lowered, and it tends to be difficult to obtain a uniform light diffusion function.

  Here, in the present specification, “major axis” and “minor axis” are, for example, when the first irregularly shaped particles are spherical with spherical protrusions as shown in FIG. As shown in (2), the short diameter (D) is represented by the distance from the end of (X) particle 1 to the end of (Z) particle 2, and the short diameter (D) is the particle ((X) particle or (Z) particle). Of these, the diameter of the larger particle ((X) particle 1 in FIG. 7) is represented.

Number average particle size ratio ((X) / (Z)):
First deformed particles of this embodiment, (X) and the number average particle diameter of the particles _{(L a),} (Z) the ratio of the values of the number average particle diameter of the particles _{(L b) ((L a} ) / (L _b )) is preferably 0.05 to 20.0, more preferably 0.2 to 18 and particularly preferably 0.4 to 15. When the value of (L _a ) / (L _b ) is less than 0.05, the balance between light transmittance and light diffusibility tends to be remarkably inferior. On the other hand, even if the value of (L _a ) / (L _b ) exceeds 20.0, the balance between light transmittance and light diffusibility tends to be remarkably inferior. In addition, when the particle shape is not a true spherical shape but a so-called flat shape, a spherical shape having a spherical protrusion as shown in FIG. 1, the average value of the long diameter and the short diameter is referred to as “average particle diameter”. To do. That is, the value of (L _a ) / (L _b ) is calculated using the value of “average particle diameter”.

Refractive index ratio:
First deformed particles of this embodiment, the refractive index of the (X) particles _{(R a),} (Z) the ratio of the values of the refractive index of the particles _{(R b) ((R a} ) / (R b) ) Is preferably 0.7 to 1.4, more preferably 0.8 to 1.3, and particularly preferably 0.85 to 1.25. When the value of (R _a ) / (R _b ) is less than 0.7, it is difficult to obtain irregularly shaped particles. On the other hand, even if the value of (R _a ) / (R _b ) exceeds 1.4, it tends to be difficult to obtain irregularly shaped particles. The refractive index is a value measured by the following method.

[Refractive index measurement]:
(1) Particles to be measured are dried at 80 ° C. for 24 hours and then crushed and filtered through a 60 mesh wire net to prepare a test sample (dried primary particles). (2) A primary particle dispersion is prepared by mixing the prepared dried primary particles and a refractive index standard solution (Cargille) having an appropriate refractive index. (3) The prepared primary particle dispersion is observed with a microscope to check whether or not the outline of the primary particles is visible, and the refractive index of the refractive index standard solution in the case where the primary particle dispersion is not visible, that is, can be visually confirmed. The refractive index of the refractive index standard solution when it was not possible was defined as the “refractive index” of the particles.

Surface exposure ratio (X / Z):
The ratio (area ratio = (a) / (b) of the exposed surface formed by (X) particles and the exposed surface formed by (Z) particles in the total surface area of the first deformed particles of the present embodiment. )) Is preferably 5/95 to 95/5, and more preferably 10/90 to 90/10. When the ratio of either one of the (X) particles and the (Z) particles is less than the above range, the effect due to the irregular particles being “abnormal” may not be sufficiently obtained. In addition, the ratio of the exposed surface of the (X) particle | grains and the (Z) particle | grains which occupies for the total surface area of a 1st irregular shape particle | grain can be measured from an electron micrograph, for example.

(First production method of irregularly shaped particles)
Step (1):
The first deformed particles of the present embodiment can be produced, for example, according to the method shown below. First, (X) particles made of the first polymer are obtained by a usual emulsion polymerization method using an aqueous medium (step (1)). 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.

Emulsion polymerization conditions:
The conditions for emulsion polymerization may be in accordance with known methods. For example, when the total amount of monomers used is 100 parts by mass, 100 to 500 parts by mass of water is used, and the polymerization temperature is -10 to 100 ° C (preferably -5 to 100 ° C, more preferably 0 to 0. 90 ° C.) and a polymerization time of 0.1 to 30 hours (preferably 2 to 25 hours). As a method of emulsion polymerization, a batch method in which monomers are charged at once, a method in which monomers are divided or continuously supplied, a method in which a monomer pre-emulsion is divided or continuously added, or these A method that combines 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.

  When an initiator is used in the emulsion polymerization, the initiator includes 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 combining a reducing agent such as a radical emulsifier, sodium hydrogen sulfite, and ferrous sulfate; 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 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, and α-methylstyrene dimer are more preferably used.

  The polymerization conversion rate of the monomer at the end of the emulsion polymerization is preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 95% by mass or more. When the monomer for the second polymer is added in a state where the polymerization addition rate of the first polymer is less than 80% by mass, the formed (X) particles and (Z) particles are difficult to clearly separate. Become. That is, the (X) particles made of the first polymer obtained are usually spherical particles.

Number average particle size:
(X) The number average particle diameter of the particles is preferably 0.1 to 10 μm, and more preferably 0.2 to 10 μm. (X) If the number average particle diameter of the particles is outside this range, it may be difficult to produce by emulsion polymerization.

Step (2):
Next, in the presence of the obtained (X) particles, a monomer for the second polymer, that is, an aromatic vinyl monomer used for constituting the structural unit (m1), The polar functional group-containing monomer and the other monomer constituting the structural unit (m3) are polymerized accordingly (step (2)).

Seed polymerization:
More specifically, at least a part of the surface of the (X) particles is obtained by seed-polymerizing the monomer for the second polymer in a state where the obtained (X) particles are used as seed polymer particles. (Z) particles arranged in the can be obtained. Specifically, the monomer for the second polymer or a pre-emulsion thereof may be added all at once, in a divided manner, or continuously in an aqueous medium in which (X) particles are dispersed.

  The amount of (X) particles used at this time is preferably 1 to 10000 parts by mass, more preferably 2 to 9000 parts by mass, with respect to 100 parts by mass of the monomer for the second polymer. preferable. In the case of using an initiator or an emulsifier at the time of polymerization, the same ones as in the production of the (X) particles can be used. Further, the conditions such as the polymerization time may be the same as in the production of the (X) particles.

  (X) When the monomer for the second polymer is charged into the aqueous medium in which the particles are dispersed, as shown in FIG. 8, most of the charged monomer for the second polymer is Usually, the (X) particles are once occluded, and polymerization is started in or on the (X) particles. The monomer for the second polymer is less compatible with the first polymer as the polymerization proceeds, and phase separates from the first polymer. For this reason, at the initial stage of the polymerization, the polymerization can proceed at a plurality of locations of the (X) particles. If the monomer units constituting each polymer satisfy the relationship described so far, the second polymer As shown in FIG. 9, the (X) particles polymerized at various points tend to gather together to form a single (Z) particle. When the (Z) particles grow to a certain size, as shown in FIG. 10, the subsequent polymerization proceeds mainly with the (Z) particles. In this way, the first deformed particles of the present embodiment in which the (X) particles and the (Z) particles are separated asymmetrically are formed.

Number average particle size:
The number average particle diameter of the first deformed particles of the present embodiment obtained as described above is 0.3 to 8 μm, preferably 0.6 to 8 μm, and more preferably 0.8 to 8 μm. . When the number average particle diameter is smaller than 0.3 μm, sufficient light diffusibility may not be obtained. On the other hand, when it is larger than 8 μm, it may be difficult to produce by an emulsion polymerization method. In addition, the “number average particle diameter” of the first deformed particles of the present embodiment refers to the length of the first deformed particles with respect to the longest direction, and can be measured by, for example, a light scattering method.

The shape of the first irregular particle:
The shape of the first irregularly shaped particles depends on the mass ratio of (X) particles and (Z) particles, the separability of (X) particles and (Z) particles, the polymerization conditions when forming (Z) particles, etc. Various changes. For example, when the mass ratio of the (X) particles and the (Z) particles and the polymerization conditions are constant, the shape of the first deformed particles becomes as the separability of the (X) particles and (Z) particles increases. 2, FIG. 4, and FIG.

[2] Second modified particles:
As one embodiment of the second modified particles of the present invention, (Y) hollow particles made of a third polymer, and a fourth particle disposed on at least a part of the surface of the (Y) hollow particles, (Z) particles made of a polymer, and the number average particle diameter thereof is 0.4 to 10 μm. Such second irregularly shaped particles can provide a molded article for an optical material that suppresses regular reflection light on the surface, is excellent in light diffusibility, and is also excellent in linear transmittance.

[2-1] (Y) Hollow particles:
The (Y) hollow particles constituting the second modified particles of the present embodiment are made of a third polymer. By having such a (Y) hollow particle, the light scattering effect on the inner wall surface of the particle shell, that is, (Y) the light irradiated to the hollow particle, in addition to the surface of the particle, has a cavity inside the particle. There is an advantage that a light scattering effect due to being reflected by the inner wall surface is remarkably added, and higher light diffusibility is exhibited. The seed polymer particles are preferably seed polymer particles capable of absorbing an oil-soluble polymerization initiator containing an organic compound having a water solubility of ^10-2 % by mass or less. As used herein, “hollow particle” means a particle in which a single void is formed inside the particle.

  (Y) The thickness of the outer shell of the hollow particles is preferably 0.05 to 3.0 μm, more preferably 0.07 to 2.0 μm, and 0.1 to 1.0 μm. Is particularly preferred. If the thickness is less than 0.05 μm, the particles may be easily crushed by an external force or the like. On the other hand, if it exceeds 3.0 μm, sufficient light diffusibility may not be exhibited.

Third polymer:
The third polymer includes (a1) a structural unit derived from an aromatic vinyl monomer (hereinafter also referred to as “structural unit (a1)”), and (a2) a structural unit derived from a polar functional group-containing monomer. (Hereinafter also referred to as “structural unit (a2)”) and, if necessary, (a3) a structural unit derived from another monomer unit (hereinafter also referred to as “structural unit (a3)”). preferable.

((A1) aromatic vinyl monomer unit):
Examples of the aromatic vinyl monomer used for constituting the structural unit (a1) include styrene, α-methylstyrene, vinyltoluene, p-methylstyrene, 2-methylstyrene, 3-methylstyrene, and 4-methyl. Styrene, 4-ethylstyrene, 4-tert-butylstyrene, 3,4-dimethylstyrene, 4-methoxystyrene, 4-ethoxystyrene, 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 2,4- Examples include dichlorostyrene, 2,6-dichlorostyrene, 4-chloro-3-methylstyrene, divinylbenzene, 1-vinylnaphthalene, 2-vinylpyridine, 4-vinylpyridine, and the like. Among these, styrene, divinylbenzene, and α-methylstyrene are preferable. These aromatic vinyl monomers can be used singly or in combination of two or more.

Ratio of structural unit (a1):
The proportion of the structural unit (a1) contained in the third polymer is 60 to 98 mass when the total of the structural unit (a1), the structural unit (a2), and the structural unit (a3) is 100 mass%. %, More preferably 65 to 95% by mass, and particularly preferably 70 to 90% by mass. When the proportion of the structural unit (a) contained in the third polymer is less than 60% by mass, it tends to be difficult to obtain hollow particles favorably. On the other hand, if it exceeds 98% by mass, it tends to be difficult to obtain irregularly shaped particles.

((A2) polar functional group-containing monomer):
The polar functional group-containing monomer used for constituting the structural unit (a2) is a monomer having a polar functional group in the molecule. Preferred examples of the polar functional group include a carboxyl group, a cyano group, a hydroxyl group, and a glycidyl group. Specific examples of the polar functional group-containing monomer include (1) carboxyl group-containing monomer, (2) cyano group-containing monomer, (3) hydroxyl group-containing monomer, and (4) glycidyl group-containing monomer. And (5) an ester group-containing monomer. In addition, the monomer illustrated below can be used individually by 1 type or in combination of 2 or more types.

  (1) Examples of the carboxyl group-containing monomer include (meth) acrylic acid, crotonic acid, cinnamic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, monomethyl maleate, maleic acid Examples thereof include carboxyl group-containing unsaturated monomers such as monoethyl, monomethyl itaconate, monoethyl itaconate, and mono-2- (meth) acryloyloxyethyl hexahydrophthalate, and anhydrides thereof. Among these, (meth) acrylic acid is preferable.

  (2) Examples of the cyano group-containing monomer include vinyl cyanide monomers such as (meth) acrylonitrile, crotonnitrile, and cinnamic acid nitrile; 2-cyanoethyl (meth) acrylate, 2-cyanopropyl (meth) ) Acrylate, 3-cyanopropyl (meth) acrylate, and the like. Among these, (meth) acrylonitrile is preferable.

  (3) Examples of the hydroxyl group-containing monomer include hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxycyclohexyl (meth) acrylate, and neopentyl glycol. Hydroxy (cyclo) alkyl mono (meth) acrylates such as mono (meth) acrylate; substituted hydroxy (cyclo) such as 3-chloro-2-hydroxypropyl (meth) acrylate and 3-amino-2-hydroxypropyl (meth) acrylate ) Alkyl mono (meth) acrylates. Among these, hydroxymethyl (meth) acrylate is preferable.

  (4) Examples of the glycidyl group-containing monomer include allyl glycidyl ether, glycidyl (meth) acrylate, methyl glycidyl methyl acrylate, epoxidized cyclohexyl (meth) acrylate, and the like. Among these, glycidyl (meth) acrylate is preferable.

  (5) Examples of the ester group-containing monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (tertiary) butyl (meth) acrylate, and n-hexyl (meth) acrylate. , 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, p-methoxycyclohexyl (meth) acrylate, trimethylolpropane tri (meth) acrylate, and the like. Among these, methyl (meth) acrylate and (tertiary) butyl (meth) acrylate are preferable.

Ratio of structural unit (a2):
The proportion of the structural unit (a2) contained in the third polymer is 2 to 40 when the total of the structural unit (a1), the structural unit (a2), and the structural unit (a3) below is 100% by mass. It is preferably mass%, more preferably 4 to 35 mass%, and particularly preferably 8 to 30 mass%. When the proportion of the structural unit (a2) contained in the third polymer is less than 2% by mass, it tends to be difficult to obtain irregularly shaped particles. On the other hand, if it exceeds 40% by mass, the light diffusibility tends to be inferior.

(Other monomer units):
The third polymer may contain a structural unit (a3) derived from a monomer unit composed of other monomers copolymerizable with the above-mentioned various monomers, if necessary. Examples of other monomers constituting the structural unit (a3) include N-methylol unsaturated carboxylic acid amides such as N-methylol (meth) acrylamide and N, N-dimethylol (meth) acrylamide; 2 -Aminoalkyl group-containing acrylamides such as dimethylaminoethylacrylamide; unsaturated carboxylic acids such as (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N, N-ethylenebis (meth) acrylamide, maleic acid amide, maleimide Amides or imides; N-monoalkyl (meth) acrylamides such as N-methylacrylamide and N, N-dimethylacrylamide; N, N-dialkylacrylamides; Aminoalkyl such as 2-dimethylaminoethyl (meth) acrylate Group-containing (meth) a Relates; aminoalkoxyalkyl group-containing (meth) acrylates such as 2- (dimethylaminoethoxy) ethyl (meth) acrylate; vinyl halide compounds such as vinyl chloride, vinylidene chloride and fatty acid vinyl esters; Conjugated diene compounds such as butadiene, 2-methyl-1,3-butadiene, 2-chloro-1,3-butadiene, 2,3-dimethyl-1,3-butadiene,

  (Cyclo) such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, etc. ) Alkyl (meth) acrylates; alkoxy (cyclo) alkyl (meth) acrylates such as 2-methoxyethyl (meth) acrylate and p-methoxycyclohexyl (meth) acrylate; diethylene glycol di (meth) acrylate, trimethylolpropane tri ( Examples thereof include polyvalent (meth) acrylates such as (meth) acrylate; ester group-containing compounds such as vinyl esters such as vinyl acetate, vinyl propionate and vinyl versatate.

Ratio of structural unit (a3):
The proportion of the structural unit (a3) contained in the third polymer is 0 to 40 when the total of the structural unit (a1), the structural unit (a2), and the structural unit (a3) below is 100% by mass. It is preferable that it is mass%, It is still more preferable that it is 0-30 mass%, It is especially preferable that it is 0-20 mass%. When the proportion of the structural unit (a3) contained in the third polymer is more than 40% by mass, the light diffusion performance tends to be lowered.

  Preferable specific examples of the third polymer include a styrene polymer, a styrene-butadiene copolymer, a styrene- (meth) acrylic acid ester copolymer, and the like.

[2-2] (Z) particles:
The (Z) particles constituting the second deformed particles of the present embodiment are composed of the fourth polymer (Y) disposed on at least a part of the surface of the hollow particles, and the first described above. The same particles as the (Z) particles constituting the irregularly shaped particles can be used.

Fourth polymer:
The fourth polymer has, for example, (b1) aromatic vinyl monomer units (hereinafter also referred to as “structural units (b1)”), (b2) (meth) acrylate compounds (hereinafter, It is preferable that it also includes “structural unit (b2)”) and (b3) other monomer units (hereinafter also referred to as “structural unit (b3)”).

((B1) aromatic vinyl monomer unit):
Examples of the aromatic vinyl monomer used for constituting the structural unit (b1) include the same aromatic vinyl monomers used for constituting the structural unit (a1). Can do. Of these, styrene, divinylbenzene, and α-methylstyrene are preferable. These aromatic vinyl monomers can be used singly or in combination of two or more.

((B2) (meth) acrylate compound):
The (meth) acrylate compound used for constituting the structural unit (b2) is a monomer having a (meth) acryl group in the molecule. Specific examples of such (meth) acrylate compounds include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, n-hexyl (meth) acrylate, 2- (Cyclo) alkyl (meth) acrylates such as ethylhexyl (meth) acrylate and cyclohexyl (meth) acrylate; alkoxy (cyclo) alkyl (meth) such as 2-methoxyethyl (meth) acrylate and p-methoxycyclohexyl (meth) acrylate Acrylates; polyvalent (meth) acrylates such as trimethylolpropane tri (meth) acrylate are preferred, and methyl (meth) acrylate is more preferred. These (meth) acrylate compounds can be used singly or in combination of two or more.

(Other monomer units):
The fourth polymer may contain a monomer unit (also referred to as a structural unit (b3)) composed of other monomers copolymerizable with the above-mentioned various monomers, if necessary. Good. As the other monomer constituting the structural unit (b3), the (meth) acrylate compound is removed from the other monomer that may be used to constitute the structural unit (a3). The thing similar to a thing can be mentioned.

(Second deformed particle):
The second deformed particle of this embodiment has (Y) hollow particles and (Z) particles, and the (Z) particles are arranged on at least a part of the surface of the (Y) hollow particles. Is.

The composition of the third polymer and the composition of the fourth polymer:
In the second modified particles of the present embodiment, the composition of the third polymer and the composition of the fourth polymer may be the same or different, but the single polymer contained in the third polymer is different. It is also preferred that at least one of the monomer units is different from the monomer unit contained in the fourth polymer. That is, in this case, at least one of the monomer units constituting the second deformed particle is contained only in one of the third polymer and the fourth polymer. become. Thereby, for example, (Y) particles and (Z) particles can be separated asymmetrically.

Ratio of number average value of major / minor axis:
The second deformed particle of the present embodiment has a ratio value ((L) / (D)) of the number average value (L) of the major axis and the number average value (D) of the minor axis of 1.0. Is preferably 2.0, more preferably 1.1 to 1.9, and particularly preferably 1.2 to 1.8. When the value of (L) / (D) is more than 2.0, dispersibility in the binder component is lowered, and it tends to be difficult to obtain a uniform light diffusion function.

(Y) Hollow particle / (Z) number average particle size ratio:
Second deformed particles of this embodiment, the number average particle diameter (Y), hollow particles (L _{a), (Z)} the ratio of the values of the number average particle diameter of the particles _{(L b) ((L a} ) / (L _b )) is preferably 0.05 to 20.0, more preferably 0.2 to 18, and particularly preferably 0.4 to 15. When the value of (L _a ) / (L _b ) is less than 0.05, the balance between light transmittance and light diffusibility tends to be remarkably inferior. On the other hand, even if the value of (L _a ) / (L _b ) exceeds 20.0, the balance between light transmittance and light diffusibility tends to be remarkably inferior.

(Y) Hollow particle / (Z) particle refractive index ratio:
Second deformed particles of this embodiment, (Y) refractive index of the hollow particles and _{(R a),} (Z) the ratio of the values of the refractive index of the particles _{(R b) ((R a} ) / (R b )) Is preferably 0.7 to 1.4, more preferably 0.8 to 1.3, and particularly preferably 0.85 to 1.25. When the value of (R _a ) / (R _b ) is less than 0.7, it is difficult to obtain irregularly shaped particles. On the other hand, even if the value of (R _a ) / (R _b ) exceeds 1.4, it tends to be difficult to obtain irregularly shaped particles. The refractive index is a value measured by the method of [Refractive Index Measurement] already described above.

Surface exposure ratio (X / Z):
Of the total surface area of the second modified particles of the present embodiment, the ratio of the exposed surface formed by (Y) hollow particles and the exposed surface formed by (Z) particles (area ratio = (a) / ( b)) is preferably 5/95 to 95/5, more preferably 10/90 to 90/10. When the ratio of either one of (Y) hollow particles and (Z) particles is less than the above range, the effect due to the fact that the second deformed particles are “deformed” may not be sufficiently obtained. . In addition, the ratio of the exposed surface of the (Y) particle | grains and the (Z) particle | grains which occupies for the total surface area of 2nd irregular shape particle | grains can be measured from an electron micrograph, for example.

Reactive functional group:
A polymer having an ester group, an amide group, an amine group, a carboxyl group, a glycidyl group, or a hydroxyl group as a reactive functional group may be obtained by, for example, copolymerizing monomers having these reactive functional groups, or It can be obtained by grafting a compound having a reactive functional group. The polymer having a sulfonic acid group can be obtained, for example, by polymerizing a monomer in the presence of a reactive surfactant having a sulfonic acid group. Moreover, the polymer which has a sulfate group can be obtained by polymerizing a monomer using initiators, such as potassium persulfate, for example. The amount of the reactive functional group contained in the third polymer and / or the fourth polymer is calculated based on the total amount of each polymer in terms of the compound used for the introduction of the reactive functional group. 0.5 to 50% by mass is preferable, and 2 to 30% by mass is more preferable.

(Method for producing second irregularly shaped particles):
The 2nd irregular shape particle of this embodiment can be manufactured according to the method shown below, for example.

  First, (Y) hollow particles made of a third polymer are prepared by using particles made of a polymer having a carboxylic acid such as a methyl methacrylate / methacrylic acid copolymer as seed particles, and using third particles in an aqueous medium. Emulsion polymerization of the monomer for coalescence gives core-shell particles having the third polymer as a core (step (a-1)), and then the core is swollen by adding a basic substance such as ammonia. (Step (a-2)). 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.

Step (a-1):
Preparation of seed particles:
In this step, first, unsaturated carboxylic acid (c1) (hereinafter sometimes referred to as “monomer (c1)”) and radical polymerizable monomer (c2) (hereinafter sometimes referred to as “monomer (c2)”). Seed particles are prepared by emulsion polymerization of a monomer mixture (c) consisting of in an aqueous medium.

  Examples of the monomer (c1) include mono- or dicarboxylic acids such as (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid, acid anhydrides, monoalkyl esters, monoamides of the dicarboxylic acid, and the like. be able to. Among these, (meth) acrylic acid, itaconic acid and the like are preferable from the viewpoint that the obtained particles have good stability. These can be used individually by 1 type or in combination of 2 or more types.

  Examples of the monomer (c2) include unsaturated carboxylic acid esters; aromatic monomers such as styrene and α-methylstyrene; (meth) acrylonitrile; vinyl acetate; butadiene; isoprene. Among these, unsaturated carboxylic acid ester is preferable, and it is particularly preferable that 50% by mass or more of the total amount of the monomer (c2) is unsaturated carboxylic acid ester. When the unsaturated carboxylic acid ester is less than 50% by mass, the swelling action due to the volatile base described later is reduced, the formation of pores is insufficient, and even when the pores are formed, Core particles may remain in the pores.

Emulsion polymerization of the third monomer:
The conditions for emulsion polymerization may be in accordance with known methods. For example, when the total amount of monomers used is 100 parts by mass, 100 to 500 parts by mass of water is used, and the polymerization temperature is -10 to 100 ° C (preferably -5 to 100 ° C, more preferably 0 to 0. 90 ° C.) and a polymerization time of 0.1 to 30 hours (preferably 2 to 25 hours). As a method of emulsion polymerization, a batch method in which monomers are charged at once, a method in which monomers are divided or continuously supplied, a method in which a monomer pre-emulsion is divided or continuously added, or these A method that combines 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.

Initiator:
When an initiator is used in the emulsion polymerization, the initiator includes 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 combining a reducing agent such as a radical emulsifier, sodium hydrogen sulfite, and ferrous sulfate; 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.

Molecular weight regulator:
There is no restriction | limiting in particular in the molecular weight modifier used for 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.

Polymerization conversion rate:
The polymerization conversion rate of the monomer at the end of the emulsion polymerization is preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 95% by mass or more. When the polymer addition rate of the third polymer is less than 80% by mass and the monomer for the fourth polymer is added, the formed (Y) hollow particles and (Z) particles are clearly separated. It becomes difficult. That is, the obtained particles are spherical particles.

Step (a-2):
In this step, the pH of the dispersion of the core-shell polymer particles prepared in the previous step (step (a-1)) is adjusted to 7 or more with a volatile base such as ammonia or amine, and if necessary. By heating, the polymer particles are neutralized and swollen to prepare hollow polymer particles.

  Since the polymer derived from the monomer mixture (c) can penetrate a volatile base, the above treatment neutralizes the polymer particle component of the core, and accordingly, the polymer particle component of the core absorbs water significantly, The polymer particles are hollow polymer particles having pores inside.

  (Y) The number average particle diameter of the hollow particles is preferably 0.1 to 10 μm, and more preferably 0.2 to 10 μm. (Y) When the number average particle size of the hollow particles is outside this range, it may be difficult to produce by emulsion polymerization.

Step (b):
Next, in the presence of the obtained (Y) hollow particles, a monomer for the fourth polymer, that is, an aromatic vinyl monomer used to constitute the structural unit (b1), The (meth) acrylate compound used for constituting the structural unit (b2) and the other monomer constituting the structural unit (b3) used as necessary are polymerized (step (b)). . That is, in the state where the obtained (Y) hollow particles are used as seed polymer particles, the monomer for the fourth polymer is seed-polymerized, and (Y) is arranged on at least a part of the surface of the hollow particles. (Z) particles can be obtained. Specifically, the monomer for the fourth polymer or a pre-emulsion thereof may be added all at once, in a divided manner, or continuously in an aqueous medium in which (Y) hollow particles are dispersed. The amount of the (Y) hollow particles used at this time is preferably 1 to 10000 parts by mass and preferably 2 to 9000 parts by mass with respect to 100 parts by mass of the monomer for the fourth polymer. Further preferred. When an initiator or an emulsifier is used in the polymerization, the same ones as in the production of (Y) hollow particles can be used. Further, the conditions such as the polymerization time may be the same as in the production of (Y) hollow particles.

  Similar to the (Z) particles in the first deformed particles, the (Z) particles in the second deformed particles of the present embodiment grow as shown in FIGS.

Number average particle size of second irregularly shaped particles:
The number average particle diameter of the second deformed particles of the present embodiment obtained as described above is 0.4 to 10 μm, preferably 0.8 to 10 μm, more preferably 1.2 to 10 μm. When the number average particle diameter is smaller than 0.4 μm, sufficient light diffusibility may not be obtained. On the other hand, when it is larger than 10 μm, it may be difficult to produce by an emulsion polymerization method.

shape:
The shape of the second deformed particle is the same as the shape of the first deformed particle, the mass ratio of (Y) hollow particles to (Z) particles, (Y) the separability of hollow particles and (Z) particles, (Z) It varies depending on the polymerization conditions at the time of forming the particles, and tends to change as in the case of the first irregularly shaped particles.

[3] First irregular particle composition:
One embodiment of the first modified particle composition of the present invention comprises the above-mentioned (A-1) first modified particles and (B) a binder component. Therefore, the first irregularly shaped particle composition can provide a molded article for an optical material that suppresses regular reflection light on the surface, is excellent in light diffusibility, and is excellent in linear transmittance. The details will be described below.

[3-1] (A-1) First modified particles:
As the (A-1) first deformed particles contained in the first deformed particle composition of the present embodiment, the same particles as the first deformed particles of the present invention described above can be suitably used.

[3-2] (B) Binder component:
The (B) binder component contained in the first modified particle composition of the present embodiment is transparent and, for example, (A-1) disperses the first modified particles on the surface of a resin sheet or the like. The type is not particularly limited as long as it can be integrated. (B) Specific examples of the binder component include thermoplastic resins such as polyvinyl acetate, polyvinyl alcohol, polyvinyl chloride, polyvinyl butyral, poly (meth) acrylic acid ester, nitrocellulose; phenol resin, melamine resin, polyester resin, Examples thereof include thermosetting resins such as polyurethane resins and epoxy resins, and ionizing radiation curable resins that are cured by electron beam or ultraviolet irradiation, and these can be used depending on the optical material to be applied. These (B) binder components can be used singly or in combination of two or more.

Total light transmittance:
(B) The total light transmittance of the binder component is preferably 80% or more, and more preferably 90% or more. Thus, when the total light transmittance of the (B) binder component is 80% or more, it becomes possible to produce a molded article for an optical material having more excellent light transmittance.

(B) Ratio of binder component:
The ratio of the (B) binder component contained in the first modified particle composition of the present embodiment is (A-1) 1 to 10000 parts by mass with respect to 100 parts by mass of the first irregular particle. Preferably, it is 2-5000 mass parts, More preferably, it is 3-1000 mass parts. (B) 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 (A-1) first deformed particles on the surface of a resin sheet or the like. is there. On the other hand, when the content ratio of the (B) binder component is more than 10,000 parts by mass, the light diffusibility of the molded article for optical material produced using the first irregularly shaped particle composition tends to be difficult to improve.

[3-3] Other components:
In addition to (A-1) the first irregularly shaped particles and (B) the binder component, the first irregularly shaped particle composition of the present embodiment includes other components such as a curing agent, a dispersant, and a dye as necessary. These components can be contained.

  The content of other components is preferably 0 to 10 parts by mass, and 0 to 5 parts by mass with respect to 100 parts by mass as a total of (A-1) first irregularly shaped particles and (B) binder component. It is more preferable that it is 0-3 mass parts.

[4] Method for producing irregularly shaped particle composition:
In one embodiment of the method for producing a deformed particle composition of the present invention, the solvent is removed from the emulsion containing the above-mentioned (A-1) first deformed particle, and the (A-1) first in the dry state is removed. It has a step of obtaining irregular shaped particles (step (i)) and a step of mixing the obtained (A-1) first irregular shaped particles and (B) a binder component (step (ii)). By producing in this way, it is possible to obtain an irregularly shaped particle composition capable of providing a molded article for an optical material having an excellent balance between light transmittance and light diffusibility. Details will be described below.

Step (i):
In the method for producing the irregularly shaped particle composition of the present embodiment, first, an emulsion containing the first irregularly shaped particles ((A-1) first irregularly shaped particles) is obtained according to the method for producing the first irregularly shaped particles described above. Thereafter, the solvent is removed from the obtained emulsion to obtain dried first deformed particles (step (i)). In this step (i), the method for removing the solvent from the emulsion is not particularly limited, but the freeze-drying method and the spray-drying method are preferred because they can be easily dried.

  In addition, it is preferable to dry until the content rate of a solvent will be 5.0 mass% or less, and it is still more preferable to dry until it will be 3.0 mass% or less. When the content ratio of the solvent is more than 5.0% by mass, the dispersibility in (B) the binder component is lowered, and it tends to be difficult to produce a molded product exhibiting a uniform light diffusion function.

Step (ii)
Next, the dried (A-1) first deformed particles and (B) binder component obtained are mixed (step (ii)). In this step (ii), (A-1) the first irregularly shaped particles, (B) the binder component, and the above-described other components added as necessary are uniformly mixed, whereby A first irregularly shaped particle composition can be obtained. In addition, you may mix another component, after mixing (A-1) 1st unusual shape particle and (B) binder component. Although it does not specifically limit about the mixing method, For example, it can mix using various kneaders, a bead mill, a high-pressure homogenizer, etc.

[5] Second modified particle composition:
One embodiment of the second deformed particle composition of the present invention comprises (A-2) second deformed particles and (B) a binder component. Such a second irregularly shaped particle composition can provide a molded article for an optical material having an excellent balance between light transmittance and light diffusibility. The details will be described below.

[5-1] (A-2) Second modified particles:
As (A-2) second deformed particles contained in the second deformed particle composition of the present embodiment, the same particles as the second deformed particles of the present invention described above can be suitably used.

[5-2] (B) Binder component:
The (B) binder component contained in the second modified particle composition of the present embodiment is the same as the (B) binder component contained in the first modified particle composition of the present invention described above. be able to.

[5-3] Other components:
In the second modified particle composition of the present embodiment, in addition to (A-2) the second modified particle and (B) the binder component, other components such as a curing agent, a dispersant, and a dye may be used as necessary. These components can be contained.

  The content of other components is preferably 0 to 10 parts by mass, and 0 to 5 parts by mass with respect to 100 parts by mass as the total of (A-2) second modified particles and (B) binder component. It is more preferable that it is 0-3 mass parts.

Method for producing second modified particle composition:
The second modified particle composition of the present embodiment is the same as that of the first modified particle composition described above except that (A-1) the first modified particle is replaced with (A-2) the second modified particle. It can be manufactured in the same manner as the manufacturing method.

[6] First molded article for optical material:
The 1st molded article for optical materials of this invention consists of a resin material containing a resin component and the above-mentioned (A-1) 1st unusual shape particle. Such a first molded article for an optical material suppresses regular reflection light on the surface, is excellent in light diffusibility, and is excellent in linear transmittance. Therefore, the first molded article for an optical material of the present embodiment is suitable as a light guide plate, a light diffusing plate, a light diffusing film, an antiglare film, a prism sheet, or a protect sheet, taking advantage of such characteristics. Details will be described below.

Resin material:
The resin material constituting the first molded article for optical material contains a resin component and the above-mentioned (A-1) first deformed particles. Although it does not specifically limit about this resin component, The transparent thing which has high transmittance | permeability with respect to visible light is preferable. The term “transparency” conceptually includes colored transparency and translucency in addition to colorless transparency.

Resin component:
When the resin component is a sheet having a thickness of 200 μm, the light transmittance at a wavelength of 550 nm is 80% or more, and the light transmittance of the molded article for optical material can be further improved. Therefore, it is preferably 85% or more, more preferably 90% or more. In consideration of the use environment, storage environment, and the like, the glass transition temperature of the resin component is preferably 100 ° C. or higher, more preferably 120 ° C. or higher, and particularly preferably 150 ° C. or higher.

  Specific examples of the resin component include polyethylene terephthalate, polymethyl (meth) acrylate, polycarbonate, cycloolefin polymer, polyarylate, polyethersulfone, polystyrene, methyl (meth) acrylate-styrene copolymer, styrene-acrylonitrile copolymer, etc. Thermosetting resins such as epoxy resins, vinyl ether resins, (meth) acrylates having two or more (meth) acrylic groups, oxetane resins, vinyl ester resins, and the like, curable resins that can be cured with heat or active energy rays Can do. Among them, a curable resin that can be cured by heat or active energy rays is preferable because it is easily combined with glass fiber or glass fiber cloth and is thermally stable. A (meth) acrylate having a (meth) acryl group is more preferred.

(A-1) First irregularly shaped particles:
The ratio of the (A-1) first deformed particles contained in the resin material is preferably 1 to 1000 parts by mass and more preferably 1 to 500 parts by mass with respect to 100 parts by mass of the resin component. The amount is preferably 1 to 100 parts by mass. (A-1) When the content ratio of the first irregularly shaped particles is less than 1 part by mass, the light diffusibility tends not to be sufficiently improved. On the other hand, when it exceeds 1000 parts by mass, the light transmittance tends to be remarkably lowered.

Molding method for optical molded products:
The molding method of the first molded article for optical material of the present embodiment is, for example, supplying a resin component and (A-1) first deformed particles to an extruder, and a master batch obtained by extruding from the extruder. For example, the master batch can be supplied to an extruder and injected into a cavity for molding.

[7] Second molded article for optical material:
One embodiment of the second molded article for an optical material of the present invention is an optical material comprising a base material layer and the above-mentioned first irregular particle composition formed on at least one surface of the base material layer. And a layer. Such a molded article for the second optical material has excellent light transmittance and light diffusibility. Therefore, the second molded article for an optical material of the present embodiment makes use of such characteristics and is suitable as a light diffusing plate, a light diffusing film, an antiglare film, a prism sheet, a protect sheet, or the like. Details will be described below.

Base material layer:
The base material layer constituting the second optical material molded article is preferably a layer made of a transparent (colorless transparent, colored transparent, 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 first optical material molded article. Further, as the resin constituting the base layer, cyclic olefin ring-opening polymer hydrogenated product, cyclic olefin type addition polymer, polycarbonate, triacetyl cellulose (TAC), polyvinyl alcohol (PVA), polyvinyl butyral (PVB) Polyethylene terephthalate (PET), polypropylene (PP), polyarylate, polysulfone, polyethersulfone, acrylic resin and the like can also be preferably used.

  Although the thickness of a base material layer is not specifically limited, It is preferable that it is 30-300 micrometers, and it is still more preferable that it is 50-200 micrometers. Moreover, although it does not specifically limit about the thickness of a light-diffusion layer, It is preferable that it is 3-20 micrometers, and it is still more preferable that it is 3-15 micrometers.

Optical material layer:
The optical material layer formed on at least one surface of the base material layer is a layer made of the first irregularly shaped particle composition described above. The (A-1) first deformed particles contained in the first deformed particle composition are integrated on the base material layer by the (B) binder component also contained in the first deformed particle composition. ing. In addition, some (A-1) 1st irregular shape particles may be in the state which made the one part protrude from the surface of (B) binder component. Further, the protruding portion of the (A-1) first irregularly shaped particle may be entirely covered with the (B) binder component or may be partially covered. Note that (A-1) all of the first irregularly shaped particles may be completely buried in the (B) binder component.

Method for producing second molded article for optical material:
The second molded article for an optical material of the present embodiment is, for example, (A-1) a first irregularly shaped particle and (B) a binder component dispersed in (C) a solvent capable of dispersing or dissolving them. It can be manufactured by dissolving into a slurry, coating with various coaters, and drying. Specific examples of the solvent (C) include water, toluene, cyclohexane, methyl isobutyl ketone (MIBK), methyl ethyl ketone (MEK), N-methyl-2-pyrrolidone (NMP) and the like. Among these, an organic solvent is preferable.

  (C) It is preferable that the content rate of a solvent is 10-2000 mass parts with respect to 100 mass parts of total amounts of (A-1) 1st deformed particle and (B) binder component, and 20-1000 masses. More preferably, it is part.

[8] Third molded article for optical material:
One embodiment of the third molded article for an optical material of the present invention is made of a resin material containing a resin component and the above-mentioned (A-2) second deformed particles. Such a third molded article for an optical material is excellent in the balance between light transmittance and light diffusibility. Therefore, the third molded article for an optical material of the present embodiment is suitable as a light guide plate, a light diffusing plate, a light diffusing film, an antiglare film, a prism sheet, or a protect sheet, taking advantage of such characteristics.

Resin component:
As the resin component in the resin material constituting the third optical material molded article, the same resin component as that contained in the resin material constituting the first optical material molded article can be used in the same manner.

(A-2) Second modified particles:
The content ratio of the (A-2) second deformed particles contained in the resin material is the same as the (A-1) first deformed particles contained in the resin material constituting the first optical material molded article. It can be contained in proportions.

Third molding method of molded article for optical material:
As the molding method of the third molded article for optical material of the present embodiment, the same method as the molding method of the first molded article for optical material described above can be adopted.

[9] Fourth molded article for optical material:
One embodiment of the fourth molded article for an optical material of the present invention is an optical system comprising a base layer and the above-described second deformed particle composition formed on at least one surface of the base layer. And a material layer. Such a fourth molded article for an optical material is excellent in the balance between light transmittance and light diffusibility. Accordingly, the fourth molded article for optical material of the present embodiment is suitable as a light guide plate, a light diffusing plate, a light diffusing film, an antiglare film, a prism sheet, a protect sheet, or the like taking advantage of such characteristics.

Base material layer:
As the base material layer constituting the fourth optical material molded article, the same base material layer as that constituting the second optical material molded article described above can be used in the same manner.

Optical material layer:
The optical material layer constituting the fourth molded article for optical material is a layer made of the above-mentioned second deformed particle composition formed on at least one surface of the base material layer. The (A-2) second deformed particle contained in the second deformed particle composition is integrated on the base material layer by the (B) binder component also contained in the second deformed particle composition. ing. In addition, some (A-2) 2nd irregular shaped particles may be in the state which made the one part protrude from the surface of (B) binder component. Further, the protruding portion of the (A-2) second deformed particle may be entirely covered with the binder component (B) or may be only partially covered. Note that (A-2) all of the second deformed particles may be completely buried in the (B) binder component.

Fourth method for producing molded article for optical material:
The fourth molded article for optical material of the present embodiment includes, for example, (A-2) the second irregularly shaped particles and (B) the binder component dispersed in (C) an organic solvent capable of dispersing or dissolving them. Alternatively, it can be produced by dissolving it into a slurry, coating with various coaters, and drying. As the solvent (C), the same solvent as the solvent (C) that can be used for the above-described second molded article for optical materials can be used. (C) It is preferable that the content rate of a solvent is 10-2000 mass parts with respect to 100 mass parts of total amounts of (A-2) 2nd deformed particle and (B) binder component, and 20-1000 masses. More preferably, it is part.

  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]:
Measurement is performed using a laser particle size analysis system (trade name “LS13320”) manufactured by Beckman Coulter.

[Number average value of major axis (L) and number average value of minor axis (D)]:
It measures by observing using SEM (scanning electron microscope) by JEOL.

[60 ° gloss]:
Measured using a goniophotometer GP200 manufactured by Murakami Color Research Laboratory.

[Linear transmittance (light transmittance)]:
Measured using a goniophotometer GP200 manufactured by Murakami Color Research Laboratory.

[Haze]:
Measurement is performed according to JIS K7105 using a haze meter manufactured by Suga Test Instruments Co., Ltd.

[Total light transmittance]:
Using a haze meter manufactured by Suga Test Instruments Co., Ltd., the sample-free state (air) is measured as 100% according to JIS K7105.

Synthesis of polymer particles:
Example 1
After stirring and emulsifying 2 parts of t-butyl peroxy-2-ethylhexanoate (trade name “Perbutyl O” manufactured by NOF Corporation), 0.1 part of sodium lauryl sulfate and 20 parts of water, an ultrasonic homogenizer Were further microparticulated to obtain an aqueous dispersion. To the obtained aqueous dispersion, 15 parts of monodispersed polystyrene particles having a number average particle diameter of 1.0 μm (shown as “seed particles” in Table 1) were added and stirred for 16 hours. Next, 70 parts of styrene (ST), 20 parts of divinylbenzene (DVB), 10 parts of 2-hydroxyethyl methacrylate (HEMA) are added, and the mixture is slowly stirred at 40 ° C. for 3 hours to obtain monomer components (ST, DVB, and HEMA). ) Was absorbed into monodisperse polystyrene particles. Then, it heated up at 75 degreeC and performed the polymerization reaction for 3 hours, and the emulsion containing the (X) particle | grains which consist of a 1st polymer was obtained. The number average particle diameter of the (X) particles was 1.7 μm, and almost no coagulum was generated.

22.1 parts of the same aqueous dispersion as the above-mentioned aqueous dispersion and 20 parts of an emulsion containing the above (X) particles (but as solid content) were mixed and stirred for 16 hours. Next, 90 parts of styrene (ST) and 10 parts of divinylbenzene (DVB) were added, and the mixture was slowly stirred at 40 ° C. for 3 hours to absorb the monomer components (ST and DVB) in the (X) particles. Thereafter, the temperature is raised to 75 ° C. and a polymerization reaction is carried out for 3 hours to form (Z) particles composed of the second polymer, and polymer particles composed of (X) particles and (Z) particles (polymer (A An emulsion containing)) was obtained. The polymer particles have an irregular shape as shown in FIG. 1, the number average particle diameter of (Z) particles is 2.5 μm, the number average particle diameter of polymer particles is 3.8 μm, L _a (μm) / L _b (μm) = 1.7 / 2.5, and almost no coagulum was generated.

(Examples 2 and 3, Comparative Examples 1 to 4)
Except that the blending recipe of the first polymer and the second polymer is as shown in Table 1 (however, in Comparative Examples 1 and 2, the second polymer is not formed) In the same manner as in Example 1, emulsions each containing polymer particles (polymers (C) to (G)) were obtained. Various physical property values are shown in Table 2. In Table 1, the numbers represent parts by mass except for the number average particle diameter.

Preparation of polymer composition and production of light diffusion molded article:
Example 4
The emulsion containing the polymer (A) was dried using a spray dryer (model number “L-8 type”, manufactured by Okawara Chemical Co., Ltd.) to obtain a powdery polymer (A). A mixed solution obtained by mixing 50 parts of polymethyl methacrylate (polyMMA) (trade name “Parapet HR-L”, manufactured by Kuraray Co., Ltd., melt index: 2 g / 10 minutes) and 300 parts of methyl isobutyl ketone (MIBK). On the other hand, a polymer composition (first irregular particle composition) was obtained by adding and dispersing 50 parts of the powdery polymer (A).

  Subsequently, the obtained polymer composition was uniformly and layer-coated on a polyethylene terephthalate (PET) base material (total light transmittance: 87.3%, haze: 2.8%, thickness: 200 μm). Then, the optical film (optical material molded article) which has a light-diffusion layer with a thickness of 8 micrometers was obtained by drying at 60 degreeC for 3 hours. The obtained optical film had a total light transmittance of 93% and a haze of 94.5%, and had a very good balance.

(Examples 5 and 6, Comparative Examples 5 to 9)
A polymer composition was obtained in the same manner as in Example 4 except that the formulation shown in Table 3 was used. Moreover, using each obtained polymer composition, it carried out similarly to the case of the above-mentioned Example 4, and obtained the light-diffusion film (Examples 5 and 6 and Comparative Examples 5-9). Table 3 shows the thickness, total light transmittance, and haze of the light diffusion layer of the obtained optical film.

(Example 7)
Production of hollow particle polymer:
As shown in Table 4, seed polymer particles of 0.45 μm obtained by copolymerizing 80 parts of methyl methacrylate (MMA) and 20 parts of methacrylic acid (MAA) (shown as “seed particles” in Table 4) 10 Part was charged into a 2 liter flask together with 200 parts of water and 1.0 part of potassium persulfate, heated to 80 ° C. in nitrogen gas while stirring, and after reaching 80 ° C., 76 parts of styrene (ST), Polymerization was carried out by adding 20 parts of divinylbenzene, 4 parts of 2-hydroxyethyl methacrylate (HEMA), and 2 parts of t-dodecyl mercaptan. After the addition was completed, 1 part of ammonia was added all at once, and aging was performed for 2 hours. As a result, a hollow particle polymer ((Y) with a polymerization yield of 98%, a number average particle size of 1.0 μm, and a hollow ratio ({(volume of the hollow portion / volume of the whole particle) × 100 (%)}) Hollow particles) were obtained. In addition, except the thing which showed the unit, in Table 4, a number shows a mass part.

Production of hollow solid particles:
After stirring and emulsifying 2 parts of t-butyl peroxy-2-ethylhexanoate (trade name “Perbutyl O” manufactured by NOF Corporation), 0.1 part of sodium lauryl sulfate and 20 parts of water, an ultrasonic homogenizer Were further microparticulated to obtain an aqueous dispersion. The obtained aqueous dispersion was added to a mixed liquid composed of 40 parts of the hollow particle polymer obtained above and 10 parts of acetone, and stirred for 16 hours. Next, 200 parts of a 2.5% aqueous solution of polyvinyl alcohol (polymerization degree: 2000, saponification degree: 87 to 89), 80 parts of styrene (ST) and 20 parts of divinylbenzene (DVB) are added, and slowly at 40 ° C. for 3 hours. With stirring, the monomer components (ST and DVB) were absorbed by the seed polymer particles ((Y) hollow particles). Thereafter, the temperature was raised to 75 ° C., and a polymerization reaction was carried out for 3 hours. As a result, an emulsion containing second deformed particles (polymer (H)) having a polymerization yield of 98% and a number average particle diameter of 1.5 μm was obtained. The particle diameter of the solid particles ((Z) particles) is 1.0 μm, the value of the ratio (L) / (D) is 1.5, and L _a (μm) / L _b (μm) = 1.0. Met. Almost no coagulum was generated. Various physical property values are shown in Table 5.

(Examples 8 and 9, Comparative Examples 9 to 12)
Except that the blending formulation of the third polymer and the fourth polymer is as shown in Table 4, in the same manner as in Example 4 above, polymer particles (polymer ( Emulsions each containing I) to (M)) were obtained. Various physical property values are shown in Table 5.

Preparation of polymer composition and production of molded article for optical material:
(Example 10)
The emulsion containing the polymer (H) as the second irregularly shaped particles was dried using a spray dryer (model number “L-8”, manufactured by Okawara Kako Co., Ltd.) to obtain a powdery polymer (H). . (B) Obtained by mixing 50 parts of a binder component (polyMMA) (trade name “Parapet HR-L”, manufactured by Kuraray Co., Ltd., melt index: 2 g / 10 min) and 200 parts of methyl isobutyl ketone (MIBK). A polymer composition (second modified particle composition) was obtained by adding and dispersing 10 parts of the powdery polymer (H) to the mixed solution.

  Subsequently, the obtained polymer composition was uniformly coated on a TAC (triacetyl cellulose) film substrate (total light transmittance: 88.0%, haze: 3.2%, thickness: 200 μm). Then, the optical film (optical material molded article) which has a 10-micrometer-thick light-diffusion layer was obtained by drying at 60 degreeC for 1 hour. The obtained optical film had a 60 ° gloss of 18%, a haze of 34%, and a straight transmittance of 52%, and had a very good balance.

(Examples 11 and 12, Comparative Examples 13 to 17)
A polymer composition was obtained in the same manner as in Example 10 except that the formulation shown in Table 6 was used. Moreover, using each obtained polymer composition, it carried out similarly to the case of the above-mentioned Example 10, and obtained the light-diffusion film (Example 11, 12, Comparative Examples 13-17). Table 6 shows the thickness, 60 ° gloss, haze, and straight transmittance of the light diffusion layer of the obtained optical film.

(Discussion)
As shown in Table 3, the optical films of Examples 4 to 6 produced using the polymer particles of Examples 1 to 3 were the optical films of Comparative Examples 5 to 8 produced using the polymer particles of Comparative Examples 1 to 4. As compared with the film, it is clear that the balance between the total light transmittance and the haze is very excellent.

  In addition, the optical film of Comparative Examples 5 and 6 was produced using the polymer (D) and polymer (E) whose particle shape is a sphere. Thus, in the case of a spherical polymer, it is clear that it is difficult to improve the haze value as compared with irregularly shaped particles of a corresponding size (for example, Example 6; polymer (C)). is there. Further, as shown in Comparative Example 7, even when the particle shape is irregular, when the acrylic compound is included as the second polymer like the polymer (F), the thickness of the light diffusion layer is about 8 μm. When it is extremely thin, sufficient haze value cannot be improved. Further, as shown in Comparative Example 8, even when the polymer (G) having a number average particle diameter of less than 0.3 μm was used, the balance between the total light transmittance and haze was low.

  As shown in Table 6, the optical films of Examples 10 to 12 produced using the polymer particles of Examples 7 to 9 were the optical films of Comparative Examples 13 to 17 produced using the polymer particles of Comparative Examples 9 to 12. As compared with the film, it is clear that the 60 ° gloss, the haze and the straight transmittance are very excellent in balance.

  The optical film of Comparative Example 15 was prepared using a blend product obtained by simply blending a hollow polymer (K) having a spherical particle shape and a solid polymer (L). Thus, it is clear that it is difficult to improve the balance of 60 ° gloss, haze and straight transmittance by simply blending different particles without using irregularly shaped particles. Further, as is clear from Comparative Examples 16 and 17, even if the particle shape is irregular, the number average particle diameter is less than 0.4 μm, such as the polymer (M), or the polymer (N). In addition, an optical film produced using solid / solid-type irregularly shaped particles was inferior in the balance of 60 ° gloss, haze, and straight transmittance.

  The first deformed particles and the second deformed particles of the present invention are suitable as materials for light diffusion molded products such as a light guide plate, a light diffusion plate, a light diffusion film, and the like.

  The first deformed particle composition and the second deformed particle composition of the present invention are suitable as materials for light diffusion molded products such as a light guide plate, a light diffusion plate, and a light diffusion film.

  The method for producing an irregular particle composition of the present invention is a method for suitably producing an irregular particle composition that can be used as a material for a light diffusion molded article such as a light guide plate, a light diffusion plate, or a light diffusion film.

  The first light diffusion molded product to the fourth light diffusion molded product of the present invention are suitable as a light guide plate, a light diffusion plate, or a light diffusion film.

Claims (20)

  (X) particles made of the first polymer, and (Z) particles made of the second polymer disposed on at least a part of the surface of the (X) particles, and the number average particle thereof A deformed particle having a diameter of 0.3 to 8 μm. Wherein the number average particle size of (X) particles _{(L a),} the value of the ratio of the (Z) the number-average particle diameter of the particles _{(L b) is, (L a) / (L} b) = 0.05 The deformed particle according to claim 1, which is ˜20.0.   The first polymer and the second polymer both contain (m1) an aromatic vinyl monomer unit and (m3) another monomer unit. Deformed particles.   The deformed particle according to any one of claims 1 to 3, wherein the first polymer further contains (m2) a polar functional group-containing monomer unit.   The deformed particle according to any one of claims 1 to 4, wherein the (X) particle is a seed polymer particle, and the (Z) particle is formed by seed polymerization.   (A-1) An irregularly shaped particle composition comprising the irregularly shaped particle according to any one of claims 1 to 5 and (B) a binder component.   (A-1) A step of removing the solvent from the emulsion containing deformed particles according to any one of claims 1 to 5 to obtain the deformed particles in a dry state, and the obtained deformed particles and binder. And a step of mixing the components. A resin component;
(A-1) The irregularly shaped particles according to any one of claims 1 to 5;
Optical material molded product made of resin material containing   The molded article for an optical material according to claim 8, which is a light guide plate, a light diffusion plate, a light diffusion film, an antiglare film, a prism sheet, or a protection sheet. A base material layer;
A light diffusing layer made of the irregularly shaped particle composition according to claim 6, formed on at least one surface of the base material layer;
Optical material molded product with   The optical material molded article according to claim 10, which is a light diffusing plate, a light diffusing film, an antiglare film, a prism sheet, or a protect sheet.   (Y) hollow particles made of a third polymer, and (Z) particles made of a fourth polymer disposed on at least a part of the surface of the (Y) hollow particles, and the number thereof An irregularly shaped particle having an average particle diameter of 0.4 to 10 μm. Wherein (Y) and the number average particle diameter of the hollow particles _{(L a),} the value of the ratio of the (Z) the number-average particle diameter of the particles _{(L b) is, (L a) / (L} b) = 0. The irregular shaped particle according to claim 12, which is from 05 to 20.0.   The third polymer is (a1) 60 to 98% by mass of a structural unit derived from an aromatic vinyl monomer, (a2) 2 to 40% by mass of a structural unit derived from a polar functional group-containing monomer, And (a3) 0 to 30% by mass of a structural unit derived from another monomer unit, the deformed particle according to claim 12 or 13.   The fourth polymer contains at least one selected from the group consisting of (b1) a structural unit derived from an aromatic vinyl monomer and (b2) a structural unit derived from a (meth) acrylate compound. Item 15. The irregularly shaped particle according to any one of Items 12 to 14.   The deformed particle according to any one of claims 12 to 15, wherein the (Y) hollow particle is a seed polymer particle, and the (Z) particle is formed by seed polymerization. A resin component;
The irregularly shaped particles according to any one of claims 12 to 16,
An irregularly shaped particle composition comprising a resin material containing A resin component;
The irregularly shaped particles according to any one of claims 12 to 16,
Molded product for optical material made of resin material containing A base material layer;
The optical material layer comprising the irregularly shaped particle composition according to claim 18, formed on at least one surface of the base material layer,
A molded product for optical materials.   The optical material molded article according to claim 19, which is a light guide plate, a light diffusion plate, a light diffusion film, an antiglare film, a prism sheet, or a protection sheet.

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