TWI527853B - Styrene-based resin composition - Google Patents

Description

Styrene resin composition

The present invention relates to a styrene resin composition and a molded body formed from the composition. More specifically, the present invention relates to a styrene system which is excellent in light diffusibility, excellent in diffused light transmittance, yellowed without scattering light, and excellent in dimensional stability and shape stability. A resin composition and a molded body composed of the styrene resin composition.

The molded article formed of the styrene resin composition of the present invention can activate the above-mentioned excellent characteristics, and can be effectively used for a light diffusing plate such as a liquid crystal display device, a Fresnel lens, a concave-convex lens, a lighting fixture, or the like. Optical use such as electrophotography.

In a large-sized display device such as a liquid crystal television, in order to obtain sufficient brightness, an illumination method called "positive-lower type" is used, which is irradiated with light from a plurality of cold cathode tubes (CCFLs) directly under the liquid crystal panel. The light irradiation method of the "lower type" must have a light diffusion plate for causing the light image to disappear so that the light is uniformly irradiated onto the liquid crystal panel.

In recent years, in the display device industry, cost competition has become more and more severe, and accordingly, it is desired to use a cold cathode tube having a lower number of outputs to lightly illuminate the liquid crystal panel. Along with this, in order to increase the diffusibility of light and to reduce the thickness of the sheet and to reduce the cost, it is also desired to reduce the light diffusing property.

Further, with the increase in size of the display device, a light diffusing plate excellent in dimensional stability and shape stability is required.

Since styrene resin is relatively inexpensive compared with styrene-methyl methacrylate copolymer resin (MS resin) or methyl methacrylate resin, it has small saturated moisture absorption, excellent dimensional stability and shape stability. Therefore, a styrene resin composition in which a light diffusing agent is blended in a styrene resin is used to produce a light diffusing plate for a display device.

Further, it is also known that a styrene resin composition containing a light diffusing agent is used for a screen lens such as a transmissive screen, or other optical applications such as a lighting fixture or a lighting panel.

The styrene resin composition containing a light diffusing agent is (1) 80 to 99% by mass of the styrene monomer unit, 20 to 1% by mass of the methacrylic monomer unit, and other vinyl compound monomer units. In the styrene-based polymer to be used in an amount of from 5% to 10% by mass, a molded article for a screen lens or a molded article for a light-diffusing sheet having an unmelted compound having a refractive index of 1.52 or less and an average particle diameter of 1 to 20 μm is used. The styrene resin composition (see Patent Document 1), and (2) the surface layer and the inner layer are made of crosslinked styrene polymer particles having a refractive index difference of 0.005 or less with respect to the styrene polymer. The styrene resin composition of the unmelted compound is formed, and the intermediate layer is made of a crosslinked methyl methacrylate polymer particle having a refractive index difference of 0.05 to 0.15 with respect to the styrene polymer. a multilayer sheet formed of a styrene resin composition of an unmelted compound (see Patent Document 2), and (3) a styrene monomer having 1 to 10% by weight of a (meth)acrylic monomer unit - (meth)acrylic monomer copolymer Index difference of 0.04 to 0.12, weight average particle diameter of 1.0 ~ 10μm organic crosslinked particles of light diffusing styrene-based resin composition (refer to Patent Document 3), based known.

However, in the styrene resin composition of the above (1), the strength of the styrene resin is remarkably lowered by the addition of the unmelted compound of cerium oxide or crosslinked polyorganosiloxane. In addition, the styrene resin composition of the above (1) is obtained by pulverizing high-purity crystals and spheroidizing them in a high-temperature flame, and then classifying them, or pulverizing high-purity crystals, and then classifying them. The high-valent particles of the cerium oxide particles or the cross-linked polyorganosiloxane particles are not melted, and even if the styrene resin of the matrix is low, the cost of the entire styrene resin composition is high, and it is not economical. The styrene resin composition excellent in light diffusibility and a molded body obtained from the composition are provided at a price. Next, the above (1) focuses only on the average particle diameter of the unmelted compound formed of cerium oxide or crosslinked polyorganosiloxane, and does not mention any relevant particle size distribution at all. Further, in the styrene resin composition of the above (1), the average particle diameter of the unmelted compound (cerium oxide particles or crosslinked polyorganosiloxane particles) is preferably from 1 to 20 μm, more preferably from 1.5 to 19 μm. Preferably, in the examples, an unmelted compound (cerium oxide particles or crosslinked polyorganosiloxane particles) having an average particle diameter of 2 to 18 μm is used, but when an unmelted compound having an average particle diameter of 3 μm or more is used, it is difficult to use. A styrene resin composition and a molded body excellent in light diffusibility are obtained by blending a small amount of an unmelted compound.

In the above (2), the average particle diameter of the unmelted compound formed of the crosslinked methyl methacrylate polymer particles blended in the intermediate layer is 2 to 10 μm, preferably 3 to 8 μm, and the average particle size. When the diameter is less than 2 μm, the light diffusibility is lowered. However, when the average particle diameter of the crosslinked methyl methacrylate polymer particles is more than 2.5 μm, it is practically difficult to obtain a styrene resin composition or a laminated sheet having excellent light diffusibility by a small amount of the compound. Further, in the above (2), there is no mention of focusing on the particle size distribution of the crosslinked styrene polymer particles or the crosslinked methyl methacrylate polymer particles used as the unmelted compound.

In the styrene resin composition of the above (3), the weight average particle diameter of the organic crosslinked particles is preferably 3 to 8 μm, and in the examples, organic crosslinked particles having a weight average particle diameter of 3.1 to 5.5 μm are blended. However, when organic crosslinked particles having an average particle diameter of 3 μm or more are used, it is difficult to obtain a styrene resin composition and a molded article excellent in light diffusibility by a small amount of blending. Further, in the above (3), there is no mention of focusing on the particle size distribution of the organic crosslinked particles used as the light diffusing agent.

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2006-124522

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2006-168088

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2007-204536

An object of the present invention is to provide a benzene which can provide a molded article or other product having high light diffusibility, excellent diffused light transmittance, yellowing without scattering and transmitted light, and excellent dimensional stability and shape stability. A vinyl resin composition.

An object of the present invention is to provide a molded body composed of the styrene resin composition.

The resin composition in which the light diffusing agent particles are blended in the transparent resin, and the light diffusing property of the molded body formed from the composition, the refractive index difference between the resin and the light diffusing agent particles, and the particle diameter of the light diffusing agent particles, When the content of the light diffusing agent particles is related to each other, and the larger the refractive index difference between the resin and the light diffusing agent particles, or the larger the particle diameter of the light diffusing agent particles, the light diffusing coefficient is increased by one light diffusing agent particle. Big. However, as the particle size of the light diffusing agent particles is larger, the mass of the light diffusing agent particles is larger, so when the content (mass) of the light diffusing agent particles in the resin is constant, the light diffusing agent particles contained in the resin are The number of the light diffusing agent particles is less than the number of the light diffusing agent particles contained in the resin, and the light diffusing performance of all the light diffusing properties is not necessarily high.

Further, when the particle diameter of the light diffusing agent particles contained in the transparent resin is too small, light having a short wavelength is more strongly scattered, and the wavelength dependence of the scattered light is increased, so that the scattered transmitted light has a yellow color. phenomenon.

Further, when the difference in refractive index between the transparent resin and the light diffusing agent particles is too large, the total light transmittance is lowered, and for example, when a light diffusing plate, a transmissive screen, a lighting fixture, a lighting panel, or the like as a display device is used, I can't get enough brightness.

In addition, when the light diffusing agent particles contained in the transparent resin are insufficient in heat resistance, and the original form or characteristics of the light diffusing agent particles are lost during melt molding, the properties as the light diffusing agent particles are not exhibited.

The present inventors have considered that when a light diffusing agent particle is contained in a styrene resin and a light diffusing styrene resin composition is produced, it has high light diffusibility and prevents yellow light from being transmitted and transmitted. In the case of a high total light transmittance, the balance between the light diffusing coefficient of the light diffusing agent particles contained in each styrene resin and the number (amount) of the light diffusing agent particles contained in the resin is The light diffusing agent particles must be made of a specific material having a refractive index difference suitable for light diffusion between the styrene resin and the styrene resin. In this case, the most suitable particle size range and particle size distribution are present.

In addition, the inventors of the present invention have reviewed the degree of crosslinking of the light diffusing agent particles which maintain the original form or characteristics of the light diffusing agent particles during the melt molding, etc., in the styrene resin composition containing the light diffusing agent particles.

Next, in view of the above circumstances, the results of the review were further examined and found to contain a volume average particle diameter of 0.7 to 2.5 μm in the styrene resin (preferably 0.8 to 2.0 μm, more preferably 0.9 to 1.5 μm). And the value of the volume average particle diameter/number average particle diameter is 1.2 or less (preferably 1.05 or less, more preferably 1.02 or less), and the particle size distribution is narrow, and the (meth) acrylate having a specific degree of crosslinking is used. When the crosslinked resin fine particles of the resin are used as a light diffusing agent, they can be maintained without being damaged by the above-described form or original characteristics of the crosslinked resin particles, and can be excellent in light diffusing property. Further, the present invention has been completed in that it has excellent diffusibility of diffused light, and does not have a styrene resin composition such as a molded article having excellent problem of dimensional stability and shape stability without scattering yellow light.

In addition, the present inventors have found that the light diffusing property can be more smoothly obtained by blending the crosslinked resin fine particles made of a (meth) acrylate resin in a specific ratio with respect to the styrene resin. And the styrene-based resin composition which is excellent in light transmittance and which does not cause light yellowing by scattering transmitted light.

In addition, the present inventors have found that the crosslinked resin fine particles are made of a (meth)acrylate resin fine particle produced by a dispersion polymerization method as a seed particle, and a vinyl monomer containing a crosslinkable monomer is absorbed therein. ‧ One or both of the crosslinked resin fine particles obtained by the crosslinking of the crosslinked resin fine particles obtained by the polymerization and the (meth)acrylate resin fine particles having a hydrolyzable alkylene group produced by the dispersion polymerization method are suitable. The average particle diameter, the particle size distribution, and the degree of crosslinking specified in the present invention are preferably used in the styrene resin composition of the present invention, and the present invention has been completed on the basis of various findings.

In other words, the styrene-based resin composition of the present invention is characterized in that the content ratio of the structural unit derived from the styrene-based monomer is 80% by mass or more based on 100% by mass of the total of all the structural units. a styrene resin composition comprising a resin (A) and a crosslinked resin fine particle (B), characterized in that the crosslinked resin fine particles (B) are crosslinked by a (meth)acrylate resin. Resin fine particles (hereinafter referred to as "requirement (b1)"), volume average particle diameter (dv) is 0.7 to 2.5 μm (hereinafter referred to as "requirement (b2)"), volume average particle diameter (dv) and number average particle diameter The ratio (dv/dn) of (dn) is 1.2 or less (hereinafter referred to as "requirement (b3)"), and the cross-linking point equivalent is set to 0.15 meq/g or more (hereinafter referred to as "requirement (b4)").

In the styrene-based resin composition of the present invention, the content ratio of the styrene-based resin (A) and the cross-linked resin fine particles (B) is 95.0% in the total of 100% by mass. 99.5 mass% and 0.5 to 5.0 mass% are preferable, and the content ratio of the structural unit derived from the styrene-based monomer constituting the crosslinked resin fine particles (B) is 80% by mass based on 100% by mass of the total of all structural units. The above is preferred.

Further, in the styrene resin composition of the present invention, the crosslinked resin fine particles (B) are contained in seed particles selected from the group consisting of fine particles of (meth)acrylate resin produced by a dispersion polymerization method. Crosslinking resin fine particles (Ba) obtained by polymerization of a vinyl monomer of a crosslinkable monomer, and crosslinking of (meth)acrylate resin fine particles having hydrolyzable alkylene group produced by a dispersion polymerization method The crosslinked resin fine particles of the crosslinked resin fine particles (Bb) are preferred.

In the molded article of the present invention, the molded article obtained from the styrene resin composition of the present invention is preferably used for a molded article for optical use.

[Effect of the invention]

The styrene resin composition of the present invention contains the crosslinked resin fine particles (B) having the above-described requirements (b1) to (b4) in the styrene resin (A), that is, the specific volume average of the present invention. The particle diameter (dv), and the ratio (dv/dn) of the volume average particle diameter (dv) to the number average particle diameter (dn) is 1.2 or less, the particle size distribution is narrow, the specific cross-linking point is specified, and the heat resistance is excellent. When the specific crosslinked resin fine particles (B) made of the (meth) acrylate resin are used as the light diffusing agent, the styrene resin composition of the present invention is used, and when it is subjected to melt molding or other molding processing under heating, It can be maintained without impairing the above-described form or characteristics of the crosslinked resin fine particles, and can smoothly produce various optical uses having high light diffusibility and excellent diffused light transmission, and scattering transmitted light does not have yellow color. An effective shaped body or article.

The molded article or product formed from the styrene resin composition of the present invention is excellent in low hygroscopicity, dimensional stability, and shape stability.

The crosslinked resin fine particles (B) are obtained by absorbing ‧ polymerization of a vinyl monomer containing a crosslinkable monomer in seed particles obtained by using (meth) acrylate resin fine particles produced by a dispersion polymerization method One or both of the crosslinked resin fine particles (B) and the crosslinked resin fine particles (Bb) obtained by crosslinking the (meth)acrylate resin fine particles having a hydrolyzable alkylene group produced by a dispersion polymerization method The specific volume average particle diameter (dv), the specific volume average particle diameter (dv), and the number average particle diameter (dn) ratio (dv/dn) specified by the present invention can be reliably and smoothly produced by the above method. And the crosslinked resin fine particles (Ba) and the crosslinked resin fine particles (Bb) having a specific cross-linking point are set, so that the above-described high light diffusing performance and good diffused light transmittance can be reliably and simply obtained, and A styrene-based resin composition of the present invention which does not cause a molded article having a yellow phenomenon in which scattered light is transmitted can be imparted.

The crosslinked resin fine particles (B) made of the (meth) acrylate-based resin used in the present invention are oxidized by the pulverization of pure crystal used as a light diffusing agent disclosed in Patent Document 1 When the amount of the unmelted compound formed by ruthenium or cross-linked polyorganosiloxane is lower than that of the unmelted compound, it is possible to provide the styrene-based resin composition and the molded article of the present invention having the above-described excellent properties at an economical price.

The styrene resin composition of the present invention and the molded article formed from the composition can be used for a light diffusing plate, a transmissive screen, or the like for a large display device such as a liquid crystal television. Optical applications such as screen lenses, lighting fixtures, and lighting panels.

In particular, the content ratio of the styrene resin (A) and the crosslinked resin fine particles (B) in the styrene resin composition of the present invention is 95.0 to 99.5% by mass in total of 100% by mass. And 0.5 to 5.0% by mass, the physical properties required for a light diffusing plate used in a conventional liquid crystal panel can be manufactured at a reduced cost (the light diffusing rate of a plate thickness of 1.5 mm is 70% or more, and the total light transmittance is not only reduced) a light diffusing plate of 60% to 65% and a yellow light having a diffused transmitted light of 20 or less), and a light-emitting plate used in recent years using a cold cathode tube having a relatively high number of outputs A light diffusing plate that requires light of a material (a light diffusing rate of 90% or more, a total light transmittance of 55% to 65%, and a yellow light of a transmitted light) of 10 or less.

[In order to implement the invention]

The invention is described in detail below.

The styrene resin composition of the present invention is used to form the styrene resin (A) in terms of melt fluidity, moldability, heat resistance, moisture absorption resistance, refractive index, and the like of the styrene resin composition. The resin content of the structural unit of the styrene-based monomer is 80% by mass or more, and the styrene-based resin (A) is used as the total amount of the structural unit of 100% by mass. The content ratio of the structural unit derived from the styrene monomer is preferably 90% by mass or more, and more preferably 95 to 100% by mass.

a styrene-based monomer forming a styrene-based resin (A) such as styrene, α-methylstyrene, p-methylstyrene, o-methylstyrene, m-methylstyrene, vinyltoluene , p-ethylstyrene, pt-butyl-styrene, pn-butylstyrene, pn-hexylstyrene, p-octylstyrene, 2,4-dimethylstyrene, p-methoxy Styrene, p-phenylstyrene, o-chlorinated styrene, m-chlorinated styrene, p-chlorinated styrene, 2,4-dichlorostyrene, etc., styrene resin (A) It can be formed from one or two or more of these styrene monomers.

Among these, the styrene resin (A) is made of styrene, and it is preferable in terms of ease of availability, cost, polymerizability, and the like of the styrene resin.

When the styrene resin (A) has a structural unit derived from a styrene monomer and a structural unit derived from a monomer other than the styrene monomer, other monomers such as methyl (meth)acrylate or (methyl) (meth)acrylates such as ethyl acrylate and butyl (meth)acrylate; vinyl cyanide monomers such as (meth)acrylonitrile; (meth)acrylic acid, maleic anhydride, and maleic acid , an unsaturated carboxylic acid such as itaconic anhydride or itaconic acid or an anhydride thereof; maleimide, N-methyl maleimide, N-phenyl maleimide, N-cyclohexylmalay A monomer containing a quinone dicarboxylate such as quinone or the like. These styrene-based resins (A) may contain one or two or more structural units derived from such other monomers.

When the styrene resin (A) has a structural unit derived from another monomer, the structural unit derived from another monomer is a structural unit derived from (meth)acrylic acid or maleic anhydride, and copolymerization property, heat resistance, cost, etc. It is better.

The molecular weight of the styrene resin (A) used in the present invention is not particularly limited. The weight average molecular weight (Mw) in terms of polystyrene measured by gel chromatography (GPC), the moldability of the styrene resin composition, particularly the melt moldability, the strength of the obtained molded body, and the like It is preferably 50,000 to 1,000,000, more preferably 100,000 to 500,000.

The molecular weight distribution (Mw/Mn) of the styrene resin (A) is preferably from 1.5 to 3.5, and the strength of the obtained molded body or the like is preferable.

Further, the refractive index of the styrene resin (A) is preferably 1.55 or more, more preferably 1.57 or more, and most preferably 1.58 to 1.62.

In addition, the refractive index referred to in the present specification means a refractive index measured by a wavelength of 589 nm and 25 ° C using an Abbe refractometer based on the method of JIS K7015.

The styrene resin composition of the present invention contains crosslinked resin fine particles (B) satisfying the following requirements (b1) to (b4).

(b1) Crosslinked resin fine particles composed of a (meth) acrylate resin.

(b2) The volume average particle diameter (dv) is 0.7 to 2.5 μm.

(b3) The ratio (dv/dn) of the volume average particle diameter (dv) to the number average particle diameter (dn) is 1.2 or less.

(b4) The cross-linking point equivalent is set to be 0.15 meq/g or more.

The crosslinked resin fine particles (B) are composed of a (meth) acrylate-based resin mainly composed of a structural unit derived from (meth) acrylate (requirement (b1)), and constitute the (meth) acrylate system. The content ratio of the structural unit derived from the (meth) acrylate of the resin is preferably 50% by mass or more, more preferably 80% by mass or more, and particularly preferably 90% by mass or more, and most preferably 95 to 100% by mass. quality%. In particular, when the content ratio of the structural unit derived from the (meth) acrylate is 80% by mass or more, the refractive index of the crosslinked resin fine particles (B) can be 1.46 to 1.49.

In the (meth) acrylate resin constituting the crosslinked resin fine particles (B), when the content ratio of the structural unit derived from the (meth) acrylate is small, the refractive index of the crosslinked resin fine particles (B) is likely to be increased. The difference in refractive index between the styrene resin (A) and the crosslinked resin fine particles (B) is small, and the light diffusibility of the styrene resin composition and the molded body formed from the composition is lowered, and the weather resistance is improved. insufficient.

When the difference in refractive index with the styrene resin (A) is increased, the refractive index of the crosslinked resin fine particles (B) made of the (meth) acrylate resin is preferably 1.51 or less, and 1.46 to 1.49 is better.

A (meth) acrylate which forms a (meth) acrylate resin constituting the crosslinked resin fine particles (B), for example, a monofunctional monomer and a crosslinkable monomer. The crosslinked resin fine particles (B) usually have a structural unit derived from a crosslinkable monomer because they have a crosslinked structure. The cross-linking structure may be a compound having two or more polymerizable unsaturated bonds, or a compound having at least one polymerizable unsaturated bond and a hydrolyzable decyl group, and a decane bond by hydrolysis condensation Benchmark.

Monofunctional monomers such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, 3 butyl methacrylate, amyl methacrylate An alkyl ester of methacrylic acid such as 2-ethylhexyl methacrylate, lauryl methacrylate or stearyl methacrylate; methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, acrylic acid An alkyl ester of isobutyl acrylate, 3-butyl acrylate, amyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, stearyl acrylate, etc.; cyclohexyl (meth)acrylate, (methyl) An alicyclic group-containing ester of (meth)acrylic acid such as isobornyl acrylate; a heterocyclic group-containing ester of (meth)acrylic acid such as (meth)acrylic acid propyl acrylate or (meth)acrylic acid tetrahydrofuran ester; a hydroxyalkyl (meth)acrylate such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate or 3-hydroxypropyl (meth)acrylate; (meth)acrylic acid 2- An alkoxyalkyl ester of (meth)acrylic acid such as methoxyethyl ester. These compounds may be used singly or in combination of two or more. Further, among these, methyl methacrylate and isobutyl methacrylate are preferred in terms of heat resistance blockability, weather resistance and refractive index of the particles.

Crosslinkable monomers such as ethylene glycol di(meth)acrylate, trimethylolpropane tri(methyl)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, etc. a polyhydric alcohol ester of acrylic acid; allyl (meth) acrylate; an alkoxy decyl alkyl (meth) acrylate such as trimethoxy decyl propyl (meth) acrylate. These compounds may be used singly or in combination of two or more. Among these, in order to carry out the synthesis of a particle having a high crosslinking density in a high yield and high productivity, an alkoxyalkylalkylalkyl (meth)acrylate is preferred.

The (meth) acrylate-based resin is preferably 60% by mass based on 100% by mass of the total structural unit of the monofunctional (meth) acrylate constituting the (meth) acrylate-based resin. % or more, more preferably 65% by mass or more, and most preferably 70 to 100% by mass, based on a structural unit derived from methyl methacrylate and/or a structural unit derived from isobutyl methacrylate ( A methyl) acrylate-based resin is preferred.

The crosslinked resin microparticles (B) may be particles having a uniform composition from the surface to the inside, or may be core-shell particles. In the latter case, there is no particular limitation on the number of shell layers.

The crosslinked resin fine particles (B) used in the present invention have a volume average particle diameter (dv) of 0.7 to 2.5 μm (essential (b2)), preferably 0.8 to 2.0 μm, more preferably 0.9 to 1.5 μm.

When the volume average particle diameter (dv) of the crosslinked resin fine particles (B) is too small, the light diffusing performance of the styrene resin composition and the molded body obtained from the composition cannot be sufficiently high, and a scattering light band is generated. There is a yellow question. In addition, when the volume average particle diameter (dv) of the crosslinked resin fine particles (B) is too large, the light diffusing performance of the styrene resin composition and the molded body obtained from the composition may be lowered.

The crosslinked resin fine particles (B) used in the present invention have a ratio (dv/dn) of a volume average particle diameter (dv) to a number average particle diameter (dn) of 1.2 or less (requirement (b3)), and a ratio of 1.05 or less. Good, better than 1.02.

When the ratio of the volume average particle diameter (dv) to the number average particle diameter (dn) (dv/dn) is close to 1, the particle size distribution is narrow, and the crosslinked resin fine particles (B) have the same size.

The crosslinked resin fine particles (B) used in the present invention have a ratio (dv/dn) of a volume average particle diameter (dv) to a number average particle diameter (dn) of 1.2 or less, and a particle size portion is narrow when it is extremely close to 1. , with a uniform size.

Here, the volume average particle diameter (dv) and the number average particle diameter (dn) of the crosslinked resin fine particles (B) of the present specification are based on a particle image of the photographed crosslinked resin fine particles (B) using a scanning electron microscope. The calculated volume average particle diameter (dv) and number average particle diameter (dn), and the detailed calculation methods thereof are as described in the following examples.

The crosslinked resin fine particles (B) used in the present invention are obtained by blending crosslinked resin fine particles in a styrene resin (A), and at the time of performing molding at a high temperature, particularly in melt molding, in order to prevent crosslinked resin fine particles ( B) melting, deformation, morphological change, fusion between particles, etc., and when fully functioning as a light diffusing agent, set the crosslinking point equivalent to 0.15 meq/g or more (requirement (b4)) to 0.3 meq/ More preferably, g is more preferably 0.5 meq/g or more. The upper limit of the cross-linking point equivalent of the crosslinked resin fine particles (B) is not particularly limited, and it is not difficult to manufacture, and the cost is preferably 10 meq/g, more preferably 5 meq. /g.

When a styrene-based resin composition containing a crosslinked resin fine particle having a too small cross-linking point is used, when the molding process is performed by melt molding or the like, the crosslinked resin fine particles (B) are melted, deformed, and changed in morphology. In the case of melt coagulation or the like, a molded body excellent in light diffusibility cannot be obtained.

Here, the "cross-linking point equivalent (meq/g) of the crosslinked resin fine particles (B)" in the present specification means a crosslinkable reactive group of a crosslinkable monomer used in the production of crosslinked resin fine particles. The equivalent of the equivalent value is obtained by the following formula (I).

Crosslinking point equivalent of the crosslinked resin fine particles (B) = (D × n) / W (I) (wherein D represents the use of the crosslinkable monomer used in the production of the crosslinked resin fine particles (B) The amount (mmol), n is the number (equivalent) of the crosslinkable reactive group per one molecule of the crosslinkable monomer, and W is the mass (g) of the crosslinked resin fine particles (B).

When the crosslinked point equivalent of the crosslinked resin fine particles (B) is determined from the composition of the present invention, a thermal decomposition gas chromatography method, an ICP emission analysis method, or the like can be used.

For example, 0.03 mol (30 mmol) of ethylene glycol dimethacrylate having two crosslinkable reactive groups (methacryl fluorenyl) is used as a crosslinkable monomer, and two ethylene glycol dimethacrylates are used. The methacrylonitrile group is substantially in the form of a cross-linking reaction (cross-linking reaction by an addition reaction) to obtain 100 g of the crosslinked resin fine particles (B), and the crosslinked resin fine particles (B) are set. The joint equivalent is (30 mmol × 2) / 100 g = 0.6 meq / g. In the case of radical polymerization, the methacrylanyl group is substantially related to the crosslinking reaction.

Further, for example, 0.03 mol (30 mmol) of trimethoxydecylpropyl methacrylate having a methoxy group bonded to a ruthenium atom having 3 crosslinkable reactive groups, trimethoxydecyl propyl methacrylate In the case where 100 g of the crosslinked resin fine particles (B) are obtained by substantially reacting the three methoxy groups with the crosslinking reaction (by hydrolysis to a decyl alcohol group and forming a decane bond), the resin fine particles are crosslinked. The cross-linking point equivalent of (B) is (30 mmol × 3) / 100 g = 0.9 meq / g. In the presence of a suitable catalyst, the methoxyalkylene group is substantially related to the crosslinking reaction.

Further, the crosslinking reaction of the non-catalytic methoxydecyl group is extremely slow, and when it is compared with the presence of a catalyst, it is produced by a catalyst-free condition because substantially no crosslinking reaction or only a crosslinking reaction is carried out. In the case where only a slight amount of the methoxyalkyl group is introduced, the crosslinking point equivalent is generally set to zero.

The crosslinked resin fine particles (B) used in the present invention may be any one of crosslinked resin fine particles obtained by satisfying the above-mentioned requirements (b1) to (b4) (meth)acrylate resin, and the production method thereof is not particularly limited. limits.

In the present invention, the crosslinked resin microparticles (B) are used.

(i) crosslinked resin fine particles obtained by absorbing ‧ polymerization of a vinyl monomer containing a crosslinkable monomer in seed particles formed by fine particles of (meth) acrylate resin produced by a dispersion polymerization method ),and

(ii) Crosslinked resin fine particles (Bb) obtained by crosslinking a (meth) acrylate-based resin fine particle having a hydrolyzable alkylene group produced by a dispersion polymerization method

Preferably. The crosslinked resin fine particles (Ba) and the crosslinked resin fine particles (Bb) may be used singly or in combination.

The method for producing the (meth)acrylic crosslinked resin fine particles is generally a suspension polymerization method. Generally, in the case of suspension polymerization, it is difficult to produce (meth)acrylate-based crosslinked resin fine particles having a narrow particle size distribution and uniform size. Further, when the dispersion polymerization method is employed, (meth)acrylate resin fine particles having a narrow particle size distribution and uniform size can be produced smoothly. In this regard, it is preferred to use any one or both of the above-mentioned crosslinked resin fine particles (Ba) and the aforementioned crosslinked resin fine particles (Bb). In particular, since the requirements (b1) to (b4) can be produced relatively easily and at low cost, it is preferable to crosslink the resin fine particles (Bb).

Description of crosslinked resin microparticles (Ba).

The seed particles of the (meth) acrylate-based resin fine particles used in the production of the crosslinked resin fine particles (Ba) can be used as a dispersion stabilizer by using a carboxyl group-containing polymer monomer in a water/alcoholic polar solvent. The polymerizable monomer mainly composed of (meth) acrylate is dispersed and polymerized, and is smoothly produced.

The carboxyl group-containing polymer monomer forming the seed particles is not particularly limited as long as it has a radical polymerizable unsaturated bond at a molecular terminal or a side chain. As the radical polymerizable unsaturated bond, a terminal vinylidene group, a terminal (meth)acryl fluorenyl group, a side chain (meth) acryl fluorenyl group, a terminal styryl group, or the like can be used.

The carboxyl group-containing polymer monomer can be obtained by using a carboxyl group-containing polymerizable monomer and a monomer having a hydrophobic vinyl monomer in the presence of a polymerization initiator, preferably at a temperature of 180 ° C or higher. A compound having a vinylidene type ethylenically unsaturated compound at the terminal obtained by radical polymerization (hereinafter referred to as "polymer monomer (mml)").

a polymerizable monomer having a carboxyl group, such as an unsaturated monocarboxylic acid such as acrylic acid, methacrylic acid, crotonic acid or acryloxypropionic acid; maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid An unsaturated dicarboxylic acid such as cyclohexanedicarboxylic acid; an unsaturated acid anhydride obtained by hydrolysis to form a carboxyl group such as maleic anhydride or tetrahydrophthalic anhydride;

Hydrophobic vinyl monomer such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate , (3-) (meth)acrylic acid, amyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, etc. Alkyl (meth)acrylate; cyclohexyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate; styrene, α-methylstyrene, p-methylbenzene Ethylene, o-methylstyrene, m-methylstyrene, vinyl toluene, p-ethylstyrene, pt-butyl-styrene, pn-butylstyrene, pn-hexylstyrene, p- A styrene monomer such as octyl styrene or 2,4-dimethyl styrene.

Further, a polymerization initiator such as benzammonium peroxide, lauroyl peroxide, o-chlorobenzoyl peroxide, o-methoxybenzoyl peroxide, peroxy 3,5,5-three Methylhexyl decyl, t-butylperoxy-2-ethylhexanoate, di-t-butyl peroxide, di-t-hexyl peroxide, di-t-pentyl peroxide, t-butyl An organic peroxide such as oxidized trimethylacetate; an azo compound such as azobisisobutyronitrile, azobiscyclohexanecarbonylonitrile or azobis(2,4-dimethylvaleronitrile) a persulfate-based compound such as potassium persulfate.

Further, the carboxyl group-containing polymer monomer can be used in the presence of a monomer having a hydroxyl group-forming polymerizable monomer and a hydrophobic vinyl monomer in the presence of a chain-linking agent having a carboxyl group and a polymerization initiator. After the polymerization, the first polymer having a carboxyl group at the terminal and having a hydroxyl group in the side chain is formed, and the terminal carboxyl group contained in the first polymer is reacted with a polymerizable unsaturated compound having an epoxy group to form a second polymer. The polymer is then a compound obtained by reacting a hydroxyl group contained in the second polymer with a dicarboxylic acid anhydride (hereinafter referred to as a polymer monomer (mm2)).

A chain shifting agent having a carboxyl group, for example, a mercaptan compound such as mercaptoacetic acid, mercaptopropionic acid, mercaptobutyric acid or thiosalicylic acid.

A polymerizable monomer having a hydroxyl group such as 2-hydroxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxyl (meth)acrylate Propyl ester, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol a (meth) acrylate having a hydroxyl group such as a compound obtained by adding ε-caprolactone to 2-hydroxyethyl (meth) acrylate; o-hydroxystyrene, m-hydroxyl group Styrene, p-hydroxystyrene, o-hydroxy-α-methylstyrene, m-hydroxy-α-methylstyrene, p-hydroxy-α-methylstyrene, 2-hydroxymethyl-α- Methylstyrene, 3-hydroxymethyl-α-methylstyrene, 4-hydroxymethyl-α-methylstyrene, 4-hydroxymethyl-1-vinylnaphthalene, 7-hydroxymethyl-1- Vinyl naphthalene, 8-hydroxymethyl-1-vinylnaphthalene, 4-hydroxymethyl-1-isopropenylnaphthalene, 7-hydroxymethyl-1-isopropenylnaphthalene, 8-hydroxymethyl-1-isopropenylnaphthalene, P-vinylbenzyl alcohol and the like.

As the hydrophobic vinyl monomer and the polymerization initiator, each of the compounds used in the formation of the above polymer monomer (mm1) can be used.

A polymerizable unsaturated compound having an epoxy group, such as glycidyl (meth)acrylate, β-methylglycidyl (meth)acrylate, β-ethylglycidyl (meth)acrylate, 3-methyl-3,4-epoxybutyl (meth)acrylate, 3-ethyl-3,4-epoxybutyl (meth)acrylate, 4-methyl-(meth)acrylate 4,5-epoxypentyl ester, 2,3-epoxycyclohexylmethyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, o-vinyl benzyl Glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether, 2-vinylcyclohexene oxide, 3-vinylcyclohexene oxide, oxidation 4 - vinylcyclohexene, allyl epoxidized ether, and the like.

Dicarboxylic anhydrides such as succinic anhydride, phthalic anhydride, citraconic anhydride, methyl succinic anhydride, ethenyl malic anhydride, and the like.

Further, the polymer monomer having a carboxyl group may be polymerized using a polymerization initiator in a monomer having a carboxyl group-containing polymerizable monomer and a hydrophobic vinyl monomer to form a first polymerization group having a carboxyl group. After the reaction, a compound obtained by reacting a carboxyl group contained in the first polymer with a polymerizable unsaturated compound having an epoxy group (hereinafter referred to as "polymer monomer (mm3)") is used.

A polymerizable monomer having a carboxyl group, a hydrophobic vinyl monomer, a polymerization initiator, and a polymerizable unsaturated compound having an epoxy group may each be used as the compound exemplified above.

The weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) of the polymer monomers (mm1), (mm2), and (mm3) is preferably 1,000 Å. 100,000, and more preferably 3,000 to 30,000.

The polymerizable monomer used in the formation of the above (meth)acrylate resin fine particles is mainly composed of (meth) acrylate. In other words, the content ratio of the (meth) acrylate contained in the polymerizable monomer is preferably 50% by mass or more, more preferably 70% by mass or more, and the upper limit is usually 100% by mass.

The aforementioned (meth) acrylate, such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, 3-butyl methacrylate An alkyl ester of methacrylic acid such as amyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate or stearyl methacrylate; methyl acrylate, ethyl acrylate, propyl acrylate, An alkyl ester of acrylic acid such as n-butyl acrylate, isobutyl acrylate, 3-butyl acrylate, amyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate or stearyl acrylate; (meth)acrylic acid ring An alicyclic group-containing ester of (meth)acrylic acid such as hexyl ester or isobornyl (meth)acrylate. These compounds may be used singly or in combination of two or more kinds. Further, the above (meth) acrylate is preferably methyl methacrylate or isobutyl methacrylate.

When the (meth)acrylate resin fine particles are produced, the amount of the polymer monomer used is preferably 0.5 to 50 parts by mass, more preferably 1.0, based on 100 parts by mass of the above polymerizable monomer. ~ 20 parts by mass. Further, the (meth)acrylate resin fine particles are usually produced in the presence of a polymerization initiator.

The (meth)acrylate resin fine particles (seed particles) have a weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC), preferably 1,000 to 10,000 Å. 2,000,000, more preferably 5,000 to 1,000,000.

In addition, the vinyl monomer which is absorbed and polymerized by the seed particles of the (meth)acrylate resin fine particles obtained by the dispersion polymerization is required to contain a polyfunctional ethylene when the crosslinked resin fine particles (Ba) are formed. Base monomer. The polyfunctional vinyl monomer is preferably a polyfunctional (meth) acrylate compound excellent in polymerizability. Specifically, for example, ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, two a di(meth)acrylate of a glycol such as a (meth)acrylic acid polypropylene glycol ester; a trimethylolpropane tris(meth)acrylate; and a trimethylolpropane ethylene oxide modified product (a) a tris(meth)acrylate of a trivalent or higher polyvalent alcohol such as acrylate, tris(meth)acrylic acid glycerol ester, pentaerythritol tri(meth)acrylate, pentaerythritol tetrakis(meth)acrylate, or the like A poly(meth)acrylate such as a (meth) acrylate may be used alone or in combination of two or more.

Among these, ethylene glycol di(meth)acrylate and trimethylolpropane tris(meth)acrylate can be easily absorbed by seed particles, the crosslinking density is improved, and the polymerization stability is excellent. Better words.

The vinyl monomer which is absorbed and polymerized by the seed particles is preferably a polyfunctional vinyl monomer and a monofunctional vinyl monomer, and is preferably used for absorption by seed particles and polymerization stability. The monofunctional vinyl monomer is preferably the same or similar (meth) acrylate monomer as the (meth) acrylate constituting the seed particles, such as methyl methacrylate and isobutyl methacrylate. By using the vinyl monomer containing the monofunctional vinyl monomer, the seed particles can be swollen well, whereby the vinyl monomer can be absorbed by the seed particles, and the cross-linking can be sufficiently obtained. Resin fine particles (Ba). Further, in order to increase the difference in refractive index between the styrene resin (A) and the crosslinked resin fine particles (Ba), a high light diffusibility can be obtained, and a single polymer having a lower refractive index can be selected. The functional vinyl monomer is preferably used, for example, isobutyl methacrylate or 3-butyl methacrylate.

The ratio of the use of the seed particles and the vinyl monomer in the production of the crosslinked resin fine particles (Ba) is preferably 0.5 to 10 parts by mass, and 0.7 to 5 parts by mass based on 1 part by mass of the seed particles. Better quality.

The content of the polyfunctional vinyl monomer in the vinyl monomer absorbed by the seed particles is a set crosslinking point of the crosslinked resin fine particles (Ba) obtained by absorbing and polymerizing the vinyl monomer by the seed particles. The equivalent is an amount above the value specified in the present invention.

In general, the amount of the polyfunctional vinyl monomer used is preferably from 3 to 95% by mass, more preferably from 5 to 75% by mass, based on the total mass of the vinyl monomer.

Next, the crosslinked resin fine particles (Bb) will be described.

The (meth)acrylate resin fine particles having a hydrolyzable alkylene group used in the production of the crosslinked resin fine particles (Bb) by using a vinyl monomer having a hydrolyzable alkylene group and (meth)acrylic acid A monomer mixture of an ester monomer is obtained by dispersion polymerization. Further, the hydrolyzable decyl group means a functional group which can be crosslinked by a hydrolysis condensation reaction to form a siloxane chain.

As the vinyl monomer having a hydrolyzable alkylene group, any vinyl monomer having one or more hydrolyzable alkylene groups can be used. For example, a vinyl decane such as vinyl trimethoxy decane, vinyl triethoxy decane, vinyl methyl dimethoxy decane, vinyl dimethyl methoxy decane or the like; trimethoxy decyl propyl acrylate Ethacrylate containing hydrolyzable decyl group such as ester, triethoxy decyl propyl acrylate, methyl dimethoxy decyl propyl acrylate; trimethoxy decyl propyl methacrylate, triethyl methacrylate a methacrylic ester containing a hydrolyzable decyl group such as methoxy oxime alkyl propyl ester, methyl dimethoxy decyl propyl methacrylate or dimethyl methoxy decyl propyl methacrylate; A vinyl ether containing a hydrolyzable decyl group such as a vinyl ether containing a hydrolyzable decyl group such as a mercaptopropyl propyl vinyl ether; or a vinyl ester containing a hydrolyzable decyl group such as vinyl tridecyl decyl undecanoate. These may be used alone or in combination of two or more.

Among these, a vinyl monomer having a hydrolyzable decyl group is preferably an acrylate containing a hydrolyzable decyl group and a methacrylate containing a hydrolyzable decyl group. These monomers are excellent in copolymerizability of a (meth)acrylate monomer which is a main body of a (meth)acrylate resin fine particle having a hydrolyzable alkylene group, and excellent in weather resistance. Therefore, it is better. In particular, in terms of copolymerizability with a (meth) acrylate monomer, stability at the time of dispersion polymerization, and excellent crosslinkability, triethoxy decyl propyl methacrylate (trimethyl methacrylate) is used. Oxyalkyl propyl propyl ester is preferred.

The amount of the vinyl monomer having a hydrolyzable alkylene group is a crosslinked resin fine particle (Bb) obtained by crosslinking the (meth)acrylate resin fine particles having a hydrolyzable alkylene group obtained by dispersion polymerization. The amount of the crosslinking point equivalent is set to be equal to or higher than the value specified in the present invention.

In general, a hydrolyzable alkyl group-containing vinyl group is used for the entire mass of a monomer mixture (including a polymer monomer) used in the production of a (meth)acrylate-based resin fine particle having a hydrolyzable alkylene group. The amount of the monomer used is 2 to 50% by mass, particularly preferably 5 to 25% by mass.

The dispersion polymerization in the case of producing the (meth)acrylate resin fine particles having a hydrolyzable alkylene group is preferably carried out in an alcohol solvent, particularly a mixed solvent of an alcohol and water. Thereby, the aggregation between the particles during the polymerization can be easily suppressed, and the crosslinking after the polymerization can be carried out. Further, it is preferred to adjust the particle size and the particle size distribution by adjusting the ratio of the alcohol to the water.

Further, a (meth) acrylate monomer used in the production of a (meth) acrylate resin fine particle having a hydrolyzable decyl group, for example, methyl (meth) acrylate or ethyl (meth) acrylate, Methyl)propyl acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, 3-butyl (meth)acrylate, amyl (meth)acrylate, (meth)acrylic acid 2 -ethylhexyl ester, (meth)acrylic acid alkyl ester such as (meth)acrylic acid methacrylate, (meth)acrylic acid cyclohexyl ester, (meth)acrylic acid isobornyl ester, etc. An alicyclic group-containing ester of (meth)acrylic acid; a heterocyclic group-containing ester of (meth)acrylic acid such as (meth)acrylic acid glycidyl acrylate or (meth)acrylic acid tetrahydrofuran ester; (meth)acrylic acid 2 a hydroxyalkyl (meth)acrylate such as hydroxyethyl ester, 2-hydroxypropyl (meth)acrylate or 3-hydroxypropyl (meth)acrylate; 2-methoxyethyl (meth)acrylate An alkoxyalkyl ester of (meth)acrylic acid or the like. These compounds may be used singly or in combination of two or more. Among these, methyl methacrylate, isobutyl methacrylate, and 3-butyl methacrylate are preferable in terms of heat resistance, weather resistance, and refractive index.

The amount of the (meth) acrylate monomer used in the production of the (meth) acrylate resin fine particles having hydrolyzable alkylene group is based on the total mass of the monomer mixture (excluding the polymer monomer). In other words, it is preferably from 50 to 100% by mass, more preferably from 80 to 100% by mass.

Further, in the case of producing a dispersion polymerization of a (meth) acrylate-based resin fine particle having a hydrolyzable decyl group, it is preferred to use a polymer monomer-type dispersion stabilizer having a (meth) acrylonitrile group. When a polymer monomer type dispersion stabilizer having a (meth) acrylonitrile group is used, a target particle size can be smoothly produced by using a small amount, and a hydrolyzable decyl group having a narrow particle size distribution can be obtained. Base) acrylate resin fine particles. Further, the polymer monomer type dispersion stabilizer preferably has a carboxyl group.

The (meth) acrylonitrile group may be bonded to any one of the polymer chain end and the side chain. In particular, a polymer monomer type dispersion stabilizer which is bonded to a side chain can be preferably used by using a smaller amount of a (meth) acrylate resin fine particle having a hydrolyzable decyl group for stable production. .

a method for producing a polymer monomer having a (meth) acrylonitrile group and a carboxyl group in a side chain, for example, synthesizing a carboxyl group-containing prepolymer by an emulsion polymerization method, and then adding a part of a carboxyl group of the prepolymer A method of forming an epoxy group-containing (meth) acrylate such as glycidyl methacrylate. This method can easily produce a high performance polymer monomer. The epoxy group-containing (meth) acrylate is preferably obtained by adding 0.6 to 1.1 per polymer chain to produce fine particles having a narrower particle size distribution and a more uniform particle size.

The polymer monomer has a weight average molecular weight (Mw) in terms of styrene measured by gel permeation chromatography (GPC), preferably 500 to 50,000, more preferably 1,000 to 10,000.

A polymer monomer having a (meth)acryloyl group and a carboxyl group used in the production of a (meth)acrylate resin fine particle having a hydrolyzable alkylene group is preferably used for neutralizing and using the carboxyl group. Thereby, the (meth) acrylate type resin fine particles having hydrolyzable decyl group can be stably produced by the electrostatic reverse effect of the neutralized carboxyl anion. The amount of the base used in the neutralization is preferably 2 or less equivalents of the carboxyl group. When the amount is more than 2 times equivalent, the basicity of the reaction liquid becomes strong, and the hydrolyzable decyl group reacts during the polymerization to cause agglomeration. It is preferred to neutralize the base to use ammonium which is easily removed.

The (meth)acrylate-based resin fine particles having a hydrolyzable alkylene group can be produced by subjecting the monomer mixture containing the polymer monomer to a polymerization reaction in the presence of a polymerization initiator. As the polymerization initiator, a compound used in the formation of the above polymer monomer (mm1) can be used.

Then, the (meth)acrylate-based resin fine particles having hydrolyzable alkylene group obtained as described above are subjected to a crosslinking reaction to produce crosslinked resin fine particles (Bb).

In the crosslinking reaction, a crosslinking catalyst can be added to a dispersion containing a (meth) acrylate-based resin fine particle having a hydrolyzable decyl group to form a decane bond by a condensation reaction between hydrolyzable decyl groups. To be carried out. The catalyst for crosslinking is preferably an alkali material, and particularly preferably an ammonium or a low-boiling amine which is easily removed upon drying.

The amount of use of the alkali material is preferably 3 times by weight or more, more preferably 6 times or more, based on the alkylene group in the (meth)acrylate resin fine particles having a hydrolyzable alkylene group. More than the equivalent weight is better.

Further, the styrene resin composition of the present invention may contain an additive as described below. In the present invention, the crosslinked resin fine particles (B) may contain particles such as an antioxidant or a light stabilizer. The styrene-based resin composition of the present invention is preferably excellent in heat-resistant decomposition stability and weather resistance by containing such an additive.

The antioxidant is, for example, a phosphorus-based antioxidant, a phenol-based antioxidant, or a sulfur-based antioxidant. Among them, phosphorus-based antioxidants such as phosphoric acid, phosphate, phosphorous acid, phosphite, and the like.

Light stabilizers such as bis(2,2,6,6-tetramethyl-4-piperidyl) phthalate, bis(1,2,2,6,6-pentamethyl-4-piperidinyl) Phthalate, bismuth (2,2,6,6-tetramethyl-4-piperidinyl)-1,2,3,4-butane tetracarboxylate, hydrazine (1,2,6,6, 6-pentamethyl-4-piperidinyl-1,2,3,4-butanetetracarboxylate, poly{[6-(1,1,3,3-tetramethylpiperidinyl) Amino]hexamethylene[(2,2,6,6-tetramethylpiperidinyl)imido]}, polymethylpropyl-2-oxo-[4-(2,2,6, A hindered amine compound such as 6-tetramethyl)piperidinyl]nonane or the like.

The content ratio of the styrene resin (A) and the crosslinked resin fine particles (B) in the styrene resin composition of the present invention is preferably from 94.0 to 99.7 by mass in the total amount of 100% by mass. % and 0.3 to 6.0% by mass, more preferably 95.0 to 99.5% by mass and 0.5 to 5.0% by mass, and particularly preferably 96.0 to 99.0% by mass and 1.0 to 4.0% by mass, and most preferably 96.5 to 98.5. % by mass and 1.5 to 3.5% by mass. When the content ratio is 95.0 to 99.5% by mass and 0.5 to 5.0% by mass, the light diffusing rate of forming a sheet thickness of 1.5 mm is 70% or more, the total light transmittance is 55% to 65%, and the scattering light is transmitted. A light diffusing plate having a yellowness of 20 or less.

When the content of the crosslinked resin fine particles (B) is too small, the light diffusibility of the styrene resin composition and the molded body formed from the material is insufficient. Moreover, the transmitted light also has a yellowish condition. In addition, when the content of the crosslinked resin fine particles (B) is too large, the light transmittance of the styrene resin composition and the molded body formed from the material may be lowered.

The styrene resin composition of the present invention can be adjusted by mixing the styrene resin (A) and the crosslinked resin fine particles (B) in the above-described mass ratio. Further, in the styrene resin composition of the present invention, a part of the styrene resin (A) and the entire amount of the crosslinked resin fine particles (B) are used, and the ratio of the content ratio of the crosslinked resin fine particles (B) is adjusted in advance. In the bath, the main bath and the residual portion of the styrene resin (A) are mixed, and the styrene resin (A) and the crosslinked resin fine particles (B) can be mixed at a preferable content ratio.

In addition, when the styrene resin composition of the present invention is used to finely adjust the color tone of the diffusing property, fine particles other than the crosslinked resin fine particles (B) (hereinafter referred to as "other fine particles") may be contained as necessary. Other fine particles such as crosslinked styrene fine particles, crosslinked polyorganosiloxane fine particles, cerium oxide fine particles and the like. These other fine particles may contain one type or two or more types.

The styrene resin composition of the present invention may contain an additive within a range not impairing the object of the present invention. Additives such as light stabilizers, ultraviolet absorbers, antioxidants, antistatic agents, smoothing agents, flame retardants, colorants (dyes, pigments), fluorescent whitening agents, wavelength selective absorbers, plasticizers, and the like.

The styrene resin composition of the present invention can prepare a mixture containing a styrene resin (A), a crosslinked resin fine particle (B), and an additive selected as desired, and the mixture can be melted and kneaded by a conventional method. Manufacturing. The production apparatus, for example, a melt extruder, various kneaders, a mixer mill, or the like, can be melted at a temperature lower than the melting temperature of the styrene resin (A) and lower than the softening temperature of the crosslinked resin fine particles (B). Hybrid to be manufactured.

In the styrene-based resin composition of the present invention, a molded resin composition such as an ethylene-based resin can be produced by various conventional molding methods.

The molding method for producing a molded article is appropriately selected depending on the purpose of use, use, and the like, and is not particularly limited, and is, for example, extrusion molding, injection molding, compression molding, extrusion blow molding, injection blow molding, casting molding, and calender molding. Melt molding such as injection molding. Further, the molded body obtained by melt molding may be subjected to secondary forming processing such as bending, vacuum forming, blow molding, or press molding as needed to form a molded article of interest. In the case of optical use, depending on the purpose of use and use, a method of forming a lens shape or an embossed shape on the surface of the molded body can be used to adjust the optical characteristics.

The molded article formed of the styrene resin composition of the present invention can be effectively used for optical applications such as a light diffusing plate such as a liquid crystal display device, a Fresnel lens, a concave-convex lens, a lighting fixture, and an electrophotographic panel.

When the molded article formed of the styrene-based resin composition of the present invention is a light-diffusing sheet for a liquid crystal television, it corresponds to a backlight method (light irradiation method) used in the liquid crystal panel, for example, (1) a plate thickness of 1.5 mm. a light diffusing plate having a light diffusing rate of 70% or more, a total light transmittance of 60% to 65%, and a yellow light of a scattered transmitted light of 20 or less, (2) a light diffusivity of 90% or more, and a total light transmittance of 55. % to 60% and a light diffusing plate having a yellowness of scattered light of 10 or less.

The liquid crystal panel differs depending on the number of lamps of the backlight, the output, and the like, and the required performance of the light diffusing plate is different, and the light diffusing plate suitable for each selection is selected depending on the required performance.

In the light diffusing plate, generally, the higher the light diffusivity, the smaller the total light transmittance, and the greater the light loss rate, but with the necessary light diffusing property, and the total light transmittance is higher, and the light is lost. A light diffusing plate having a small rate and a low yellowness is preferred.

In the recent liquid crystal display device, a liquid crystal panel is produced by using a cold cathode tube having a lower output and a lower output, and the above-mentioned (2) is required to have higher light diffusibility. Performance of the light diffuser.

By using the styrene resin composition of the present invention, not only the light diffusing plate of the above (1) required for a conventional liquid crystal panel can be smoothly produced, but also the light diffusing rate can be smoothly produced at a lower cost than conventionally. The light diffusing plate of the above (2) is 90% or more, and the necessary total light transmittance is ensured, and the yellowness is 10 or less.

In the following, the invention will be specifically described by way of examples and the like, but the invention is not limited by the following examples.

[Examples] 1. Evaluation method of physical properties

In the following examples, the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the prepolymer and the polymer monomer, the number average particle diameter (dn) of the crosslinked resin microparticles (B), and the volume average particle diameter ( Dv), the ratio of the volume average particle diameter (dv) to the number average particle diameter (dn) (dv/dn), and the total light transmittance, light diffusivity, and permeation of the molded body produced from the styrene resin composition The method for measuring the yellowness (Yellow Index (YI)) is as follows.

(1) Weight average molecular weight (Mw) and number average molecular weight (Mn)

The average molecular weight (Mw) and the number average molecular weight (Mn) in terms of polystyrene were determined by gel permeation chromatography (GPC).

Specifically, the GPC apparatus uses "HLC-8120GPC" (trade name) manufactured by Tosoh Co., and the column system uses four "TSK gel super MP-M" (trade name), and uses tetrahydrofuran as a developing solvent at a flow rate of 0.6 ml. The measurement was carried out under the conditions of a column temperature of 40 ° C. The measurement rate was a solution (concentration: 5 mg/ml) in which a prepolymer or a polymer monomer was dissolved in tetrahydrofuran. The measurement results were analyzed using a test line prepared using standard polystyrene, and the weight average molecular weight (Mw) and the number average molecular weight (Mn) in terms of polystyrene were determined.

(2) Number average particle diameter (dn), volume average particle diameter (dv), and ratio (dv/dn)

The seed particles obtained in the following Synthesis Examples 8 to 12, the crosslinked resin fine particles (B) obtained in Synthesis Examples 13 to 48, and the commercially available crosslinked resin fine particles were subjected to an electric field emission scanning electron microscope (see Japanese Electric Co., Ltd.). FE-SEM) "JSM-6330F" (type name) was photographed by SEM method. In this case, the magnification of the photographic method by the SEM method is a SEM photograph in which the magnification of about 50 to 100 particles is photographed in one photograph, and the photographing position is changed, and the number of the photographic particles is 200 or more. For example, when about 50 to 60 particles are photographed in one photograph, four or more SEM photographs of the photographing position are changed.

In the case of the "particles" in the SEM photograph, the particles having a total particle diameter (maximum particle diameter) of 0.2 μm or more were clearly confirmed, and the particle diameter corresponding to the area circle obtained from the area of the particles was measured. (di), and calculating the number average particle diameter (dn) and volume of the seed particles, the crosslinked resin fine particles (B), and the commercially available crosslinked resin fine particles based on the following formula (II) and the formula (III) Average particle size (dv).

Number average particle size (dn) = (Σnidi / Σni) (II)

Volume average particle size (dv) = (Σnidi ³ /Σni) ^1/3 (III)

Next, the ratio of the volume average particle diameter (dv) to the number average particle diameter (dn) (dv/dn) is obtained from the values of the volume average particle diameter (dv) and the number average particle diameter (dn) obtained, As an indicator of particle size distribution. When the ratio of the ratio (dv/dn) is close to 1, the particle size distribution is narrow and the particle size is uniform. In addition, when the value of the ratio (dv/dn) is far from 1, the particle size distribution is wide and the particle size is inconsistent.

(3) Variation coefficient of seed particles (Cv)

The index of the particle size distribution of the particles may be a coefficient of variation (Cv) in addition to the ratio of the volume average particle diameter (dv) to the number average particle diameter (dn) (dv/dn). The coefficient of variation (Cv) of the seed particles prepared in the following Synthesis Examples 8 to 12 was obtained by the following formulas (IV) and (V).

Coefficient of variation (Cv) (%) = 100σ / dn (IV)

σ (standard deviation) = (Σ (di-dn) ² /Σni) ^1/2 (V)

(In the formula, in order to obtain di and dn in the above formula (V) when σ is obtained, the particle diameter (di) and the number average particle diameter (dn) of the above (2) can be used.

(4) Total light transmittance of the formed body

The total amount of the plate-shaped molded body (thickness: 1.5 mm ± 0.05 mm) formed by the compositions obtained in the following examples and comparative examples was measured using a haze meter "Haze Meter NDH2000" (type name) manufactured by Nippon Denshoku Co., Ltd. Transmittance (%).

(5) Light diffusivity of the formed body

A plate-shaped molded body (thickness: 1.5 mm ± 0.05 mm) made of the composition obtained in the following examples and comparative examples using a variable angle photometer "Goniophotometer GP-200" (type name) manufactured by Murakami Color Technology Co., Ltd. One side, the parallel light is irradiated at a right angle in the thickness direction, and the distribution of the transmitted light is measured on the other side, and the light diffusivity of the molded body is obtained.

Specifically, regarding the transmitted diffused light emitted from the other surface side, the illuminances I ₅ , I _{20 ,} and I _{70 at} which the emission angles θ are 5 degrees, 20 degrees, and 70 degrees, respectively, are measured, from the following formula (VI) The luminances B ₅ , B ₂₀ and B _{70 at} which the angles of incidence were 5 degrees, 20 degrees, and 70 degrees, respectively, were obtained, and then the light diffusivity of the molded body was obtained from the following formula (VII).

Brightness (B _θ )=I _θ /cosθ (VI)

Light diffusivity (%) = [{(B ₇₀ + B ₂₀ )/2} / B ₅ ] × 100 (VII)

(6) Yellowness through the light (Yellow Index (YI))

A plate-shaped molded body (thickness: 1.5 mm ± 0.05 mm) formed of the compositions obtained in the following Examples and Comparative Examples was measured and transmitted through a color difference meter "color difference meter SE2000" (type name) manufactured by Nippon Denshoku Co., Ltd. Yellow Index (YI).

2. Synthesis of polymer monomers Synthesis Example 1 (Synthesis of a polymer monomer aqueous solution (MM-1))

The mixture was filled with 3-ethoxypropionate by a hot-oil, pressurized stirred tank reactor having a capacity of 500 ml of a heating device. The reactor was warmed at about 250 ° C, and the pressure in the reactor was set to be above the vapor pressure of ethyl 3-ethoxypropionate by a pressure regulator.

Then, 20 parts by mass of methyl methacrylate, 55 parts by mass of cyclohexyl acrylate, 25 parts by mass of acrylic acid, and 0.1 part by mass of peroxide di-t-butyl group were weighed and mixed to prepare a monomer mixture liquid. Next, the monomer mixture is stored in a raw material tank.

Next, the pressure in the aforementioned reactor is kept constant, and the aforementioned monomer mixture is continuously supplied to the reactor from the raw material tank. At this time, the average residence time of the monomer mixture in the reactor was set to 12 minutes to set the supply rate. The supply amount corresponding to the monomer mixture is continuously taken out from the outlet of the reactor. In the continuous supply of the monomer mixture, the temperature in the reactor was maintained at 230 ± 2 °C. The reaction liquid taken out from the outlet of the reactor is introduced into a thin film evaporator, and volatile components such as unreacted monomers in the reaction liquid are removed to obtain a polymer monomer. 90 minutes after the start of the supply of the monomer mixture, the polymer monomer was taken from the outlet of the thin film evaporator for 60 minutes.

When the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polymer monomer are measured by gel permeation chromatography (GPC) using a tetrahydrofuran solvent, the weight average molecular weight (Mw) is 10,600. The number average molecular weight (Mn) was 3,100.

Further, the terminal ethylenically unsaturated bond introduction ratio calculated from the concentration of the terminal ethylenically unsaturated bond and the number average molecular weight (Mn) measured by ¹ H-NMR of the above polymer monomer was 98%.

After the polymer monomer obtained as described above was pulverized into pieces, 100 parts by mass of the pulverized material of the polymer monomer, 260 parts by mass of water, and 22.5 parts by mass of 25% ammonium water were placed in a glass flask equipped with a cooling tube. The polymer was heated and stirred in a 90 ° C warm bath to dissolve the polymer monomer in water. After confirming that the polymer monomer was dissolved, water was added at a concentration of the polymer monomer of 25% by mass to prepare a polymer monomer aqueous solution (MM-1). The aqueous polymer monomer solution (MM-1) had a pH of 8.0 at 25 °C.

Synthesis Example 2 (Synthesis of Polymer Monomer Solution (MM-2))

15 parts by mass of propylene glycol monomethyl ether acetate, 18.19 parts by mass of methyl methacrylate, and 39.39 parts by mass of 2-hydroxyethyl methacrylate were added to a glass container provided with a liquid supply pipe by a quantitative pump. Further, 1.77 parts by mass of 2-mercaptopropionic acid was stirred to prepare 74.35 parts by mass of a vinyl monomer mixture.

In addition, 15 parts by mass of propylene glycol monomethyl ether acetate and a 2,2'-couple manufactured by Wako Pure Chemical Industries, Ltd., which is a polymerization initiator, are added to a glass container to which a liquid supply pipe for a quantitative pump is attached. 0.17 parts by mass of nitrogen bis(2-methylbutyronitrile) "V-59" (trade name) was stirred and dissolved to prepare 15.17 parts by mass of an initiator solvent (p1).

In addition, 40 parts by mass of propylene glycol monomethyl ether acetate and 0.39 parts by mass of the above polymerization initiator were added to a glass container provided with a liquid supply pipe by a quantitative pump, and the mixture was stirred and dissolved to prepare an initiator solution ( P2) 40.39 parts by mass.

30 parts by mass of propylene glycol monomethyl ether acetate, 12.13 parts by mass of methyl methacrylate, and 2-mercapto group were added to a glass reactor equipped with a mixer, a reflux condenser, a thermometer, a nitrogen gas introduction tube, and a liquid supply pipe connection portion. 1.77 parts by mass of propionic acid, and the temperature of the reactor was adjusted to 90 ° C while blowing nitrogen gas under stirring.

Then, it was confirmed that the temperature of the mixed liquid in the reactor was a stable value of 90 ° C, and the supply of the aforementioned vinyl monomer and the aforementioned initiator solution (p1) were started to be supplied to the aforementioned reactor. The supply of these is carried out by quantitative pumping. In other words, the vinyl monomer mixture was supplied at a constant rate over 2 hours, and the initiator solution (p1) was supplied in 3 hours. After the supply of the aforementioned initiator solution (p1) is completed, the aforementioned initiator solution (p2) is directly supplied to the reactor. The supply of the initiator solution (p1) is also carried out by means of a metering pump. In other words, the aforementioned initiator solution (p2) was supplied at a constant rate over 2 hours. After the reaction, a prepolymer having a carboxyl group at one end was prepared as a polymer monomer precursor. The reaction solution was sampled, and the molecular weight was measured by GPC. The weight average molecular weight (Mw) was 4,000 and the number average molecular weight (Mn) was 2,200.

Next, air was blown in instead of blowing nitrogen gas, and 0.03 parts by mass of methoxyhydroquinone and 0.81 parts by mass of tetrabutylammonium bromide (TBAB) were added to the reactor to raise the internal temperature of the reactor to 110 °C. The temperature of the mixed liquid in the reactor was confirmed to be a stable value of 110 ° C, and 5.67 parts by mass of glycidyl methacrylate was added. The reaction was carried out at an internal temperature of 110 ° C for 6 hours to carry out a reaction of glycidyl methacrylate. The acid value of the sampled reaction liquid was measured, and the result of the addition rate of the glycidyl methacrylate to the terminal carboxyl group of the prepolymer was 98%. Further, as a result of molecular weight measurement by GPC, the weight average molecular weight (Mw) was 4,800 and the number average molecular weight (Mn) was 2,400.

After 7 hours from the addition of the glycidyl methacrylate, the internal temperature was maintained at 110 ° C, 30.30 parts by mass of succinic anhydride was added, and succinic anhydride was added to the hydroxyl group derived from 2-hydroxyethyl methacrylate. After 2 hours from the addition of succinic anhydride, the reaction liquid was cooled to contain a carboxyl group and was present at the terminal to prepare a polymer monomer solution having a methacryl oxime group. The polymer monomer solution was heated at 200 ° C for 20 minutes to obtain a polymer monomer solution (MM-2) having a solid concentration of 53.2% by mass. When the molecular weight of the polymer monomer in the polymer monomer solution (MM-2) was measured by GPC, the weight average molecular weight (Mw) was 6,800 and the number average molecular weight (Mn) was 3,600.

Synthesis Example 3 (Synthesis of Polymer Monomer Dispersion (MM-3))

In a glass container provided with a liquid supply pipe by a quantitative pump, 28.2 parts by mass of methyl methacrylate, 28.2 parts by mass of isobutyl methacrylate, 30.0 parts by mass of methacrylic acid, and 2 - thiol acid were added. 13.6 parts by mass of ethylhexyl ester was stirred to prepare a monomer mixture liquid (100 parts by mass).

200 parts by mass of ion-exchanged water was added to a glass reactor equipped with a stirrer, a reflux condenser, a thermometer, a nitrogen gas introduction pipe, and a liquid supply pipe connection portion, and the reactor temperature was adjusted to 80 while blowing nitrogen gas under stirring. °C.

After confirming that the temperature in the reactor is a stable value of 80 ° C, an initiator aqueous solution of 0.8 parts by mass of ammonium persulfate (APS) in which a polymerization initiator is dissolved in 3.0 parts by mass of ion-exchanged water is added to the reactor for 5 minutes. Thereafter, the aforementioned monomer mixture is supplied to the reactor. 100 parts by mass of the monomer mixture was supplied to the reactor at a constant speed for 120 minutes using a metering pump. After the completion of the supply, the internal temperature of the reactor was maintained at 80 ° C, and after 90 minutes from the completion of the supply, an oxidizing agent aqueous solution containing 0.1 parts by mass of peroxy-3-butyl (oxidizing agent) dissolved in 2.0 parts by mass of ion-exchanged water was added. After 5 minutes, an aqueous solution of a reducing agent in which 0.3 parts by mass of sodium hydrosulfide (reducing agent) was dissolved in 4.0 parts by mass of ion-exchanged water was added. Then, the internal temperature of the reactor was maintained at 80 ° C in 25 minutes to prepare a dispersion of the prepolymer. Next, a small amount of the prepolymer dispersion was sampled, dried, and the molecular weight was measured by GPC measurement, and the weight average molecular weight (Mw) was 3,900 and the number average molecular weight (Mn) was 1,600.

The temperature of the prepolymer dispersion in the reactor was maintained at 80 ° C, and air was blown in instead of blowing nitrogen gas, and 14.1 parts by mass of triethylamine and 0.03 parts by mass of methoxyhydroquinone were directly added. After 15 minutes, 9.47 parts by mass of glycidyl methacrylate was added, and the mixture was heated at an internal temperature of 80 ° C for 2 hours to form a glycidyl methacrylate on the carboxyl group of the prepolymer to obtain a polymer monomer. Dispersions. It was confirmed by GPC analysis that glycidyl methacrylate remained in the polymer monomer dispersion. The polymer monomer dispersion obtained was added with ion-exchanged water at a solid content of 30% by mass to obtain a polymer monomer dispersion (MM-3).

Synthesis Examples 4 to 7 (Synthesis of Polymer Monomer Solution (MM-4) to (MM-7))

Using the monomer mixture of the composition shown in Table 1, the same operation as in Synthesis Example 3 was carried out to prepare a dispersion of the prepolymer. A small amount of the prepolymer dispersion was sampled, dried, and the molecular weight was measured by GPC measurement. The weight average molecular weight (Mw) and the number average molecular weight (Mn) of each prepolymer were as shown in Table 1. Show.

Then, using the prepolymer dispersion, the addition amount of triethylamine and glycidyl methacrylate was changed to as shown in Table 1, and the same operation as in Synthesis Example 3 was carried out to obtain a solid concentration of 30 mass. % of polymer monomer dispersion (MM-4) ~ (MM-7).

The raw materials, physical properties, and the like of the polymer monomers obtained in the above Synthesis Examples 1 to 7 are shown in Table 1.

3. Synthesis of seed particles Synthesis Example 8 (Synthesis of Seed Particle Dispersion (SD-1))

32.6 parts by mass of ion-exchanged water, 92.4 parts by mass of methanol, 75 parts by mass of methyl methacrylate, and a polymer sheet prepared by the synthesis example 1 were added to a glass container provided with a liquid supply pipe by a quantitative pump. 20 parts by mass of the aqueous solution (MM-1) was stirred to prepare a monomer mixture (220 parts by mass).

Further, 150 parts by mass of ion-exchanged water, 320 parts by mass of methanol, and 50 parts by mass of methyl methacrylate are added to a glass reactor equipped with a mixer, a reflux condenser, a thermometer, a nitrogen gas introduction pipe, and a liquid supply pipe connection portion. 40 parts by mass of the aqueous polymer monomer solution (MM-1) prepared in Synthesis Example 1 was adjusted to a temperature of 52 ° C while blowing nitrogen gas under stirring.

After confirming that the temperature in the reactor was 52 ° C, 3.0 parts by mass of a tributyl methacrylate-based tributyl acrylate (trade name "Perbutyl PV"; peroxidation) was added as a polymerization initiator to the reactor. The 70% solution of trimethylacetic acid 3-butyrate (hereinafter referred to as "Perbutyl PV") was started to polymerize. It was confirmed that the reaction liquid was turbid after the addition of the polymerization initiator, and it was gradually whitened to form a milky white color to form resin fine particles.

After the addition of the polymerization initiator, after 90 minutes passed, the aforementioned monomer mixture was supplied to the reactor. In other words, 220 parts of the monomer mixture was supplied to the reactor at a constant speed over 90 minutes using a metering pump. After the supply was completed, the temperature in the reactor was raised to 70 ° C in 30 minutes, and then held at 70 ° C for 90 minutes. Then, the internal temperature was cooled to 50° C., and a part of methanol and water were removed under reduced pressure to adjust the solid content of the reaction liquid to 35.0% by mass to prepare a seed particle dispersion containing methacrylate resin fine particles (SD). -1).

The seed particle dispersion (SD-1) was subjected to centrifugal separation treatment to remove the supernatant liquid and collect fine particles. The SEM observation of the fine particles was carried out, and the number average particle diameter (dn) obtained by the image was 1.68 μm, and the coefficient of variation (Cv) was 3.50%.

Synthesis Example 9 (Synthesis of Seed Particle Dispersion (SD-2))

42.9 parts by mass of ion-exchanged water, 89.6 parts by mass of methanol, 75 parts by mass of methyl methacrylate, and a polymer monomer prepared by Synthesis Example 1 were added to a glass container equipped with a liquid supply pipe for a quantitative pump. 10 parts by mass of the aqueous solution (MM-1) was stirred to prepare a monomer mixture (217.5 parts by mass).

Further, 150 parts by mass of ion-exchanged water, 320 parts by mass of methanol, and 50 parts by mass of methyl methacrylate are added to a glass reactor equipped with a mixer, a reflux condenser, a thermometer, a nitrogen gas introduction pipe, and a liquid supply pipe connection portion. The internal temperature of the reactor was adjusted to 59.6 ° C while blowing nitrogen gas under stirring with 40 parts by mass of the aqueous polymer monomer solution (MM-1) prepared in Synthesis Example 1.

After confirming that the temperature in the reactor was a constant value of 59.6 ° C, 3.0 parts by mass of 3-butyl peroxytrimethylacetate (using "Perbutyl PV") as a polymerization initiator was added to the reactor to start polymerization. After confirming the addition of the polymerization initiator, the reaction solution was turbid, and gradually whitened to form a milky white color to form resin fine particles.

After the addition of the polymerization initiator, after 90 minutes passed, the aforementioned monomer mixture was supplied to the reactor. In other words, 217.5 parts of the monomer mixture was supplied to the reactor at a constant speed over 90 minutes using a metering pump. After the supply was completed, the temperature in the reactor was raised to 70 ° C in 30 minutes, and then held at 70 ° C for 90 minutes. Then, the internal temperature was cooled to 50° C., and a part of methanol and water were removed under reduced pressure to adjust the solid content of the reaction liquid to 35.0% by mass to prepare a seed particle dispersion containing methacrylate resin fine particles (SD). -2).

The seed particle dispersion (SD-2) was subjected to centrifugal separation treatment to remove the supernatant liquid and collect fine particles. The SEM observation of the fine particles was carried out, and the number average particle diameter (dn) obtained by the image was 2.15 μm, and the coefficient of variation (Cv) was 4.83%.

Synthesis Example 10 (Synthesis of Seed Particle Dispersion (SD-3))

50 parts by mass of methyl methacrylate and 63.75 parts by mass of methyl methacrylate were used, except that 42.5 parts by mass of methyl methacrylate and 7.5 parts by mass of isobutyl methacrylate were used instead of 50 parts by mass of methyl methacrylate in the glass reactor of Synthesis Example 8. The addition of 11.25 parts by mass of isobutyl methacrylate to 70 parts by mass of methyl methacrylate supplied in a glass container was carried out in the same manner as in Example 8 to prepare a content having a solid content concentration adjusted to 35.0% by mass. A seed particle dispersion (SD-3) of acrylate resin fine particles.

The seed particle dispersion (SD-3) was subjected to centrifugal separation treatment to remove the supernatant liquid and collect fine particles. The SEM observation of the fine particles was carried out, and the number average particle diameter (dn) obtained by the image was 1.39 μm, and the coefficient of variation (Cv) was 3.16%.

Synthesis Example 11 (Synthesis of Seed Particle Dispersion (SD-4))

50 parts by mass of methyl methacrylate and 50 parts by mass of methyl methacrylate were used, except that 35.0 parts by mass of methyl methacrylate and 15.0 parts by mass of isobutyl methacrylate were used instead of 50 parts by mass of methyl methacrylate in the glass reactor of Synthesis Example 8. In the same manner as in Example 8, except that 22.5 parts by mass of isobutyl methacrylate was used in place of 70 parts by mass of methyl methacrylate supplied in a glass container, the content of the solid content was adjusted to 35.0% by mass (methyl group). A seed particle dispersion (SD-4) of acrylate resin fine particles.

The seed particle dispersion (SD-4) was subjected to centrifugal separation treatment to remove the supernatant liquid and collect fine particles. The SEM observation of the fine particles was carried out, and the number average particle diameter (dn) obtained by the image was 1.22 μm, and the coefficient of variation (Cv) was 2.78%.

Synthesis Example 12 (Synthesis of Seed Particle Dispersion (SD-5))

200 parts by mass of ion-exchanged water, 650 parts by mass of methanol, 50 parts by mass of methyl methacrylate, and 50 parts by mass of isobutyl methacrylate were added to a glass reactor equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas introduction tube. The inside temperature of the reactor was adjusted to 54 ° C while blowing nitrogen gas under stirring with 200 parts by mass of the aqueous polymer monomer solution (MM-1) prepared in Synthesis Example 1.

After confirming that the temperature in the reactor was a constant value of 54 ° C, 3.0 parts by mass of a polymerization initiator of 3-butyl peroxyacetate (using Perbutyl PV) was added to the reactor to start polymerization. After confirming the addition of the polymerization initiator, the reaction solution was turbid, and gradually whitened to form a milky white color to form resin fine particles.

After the addition of the polymerization initiator, after 180 minutes, the temperature in the reactor was raised to an internal temperature of 65 ° C in 60 minutes, and maintained at an internal temperature of 65 ° C for 60 minutes. Then, the internal temperature was cooled to 50° C., and a part of methanol and water were removed under reduced pressure, and the solid content concentration of the reaction liquid was adjusted to 22.0% by mass to prepare a seed particle dispersion containing methacrylate resin fine particles (SD). -5). The seed particle dispersion (SD-5) was subjected to centrifugal separation treatment to remove the supernatant liquid and collect fine particles. The SEM observation of the fine particles was carried out, and the number average particle diameter (dn) obtained by the image was 0.78 μm, and the coefficient of variation (Cv) was 3.40%.

In addition, the methacrylate resin fine particles (seed particles) contained in the seed particle dispersion (SD-5) obtained in the synthesis example 12 were subjected to an electric field emission scanning electron microscope (FE-SEM) manufactured by JEOL. ) "JSM-6330F" (type name) photography. The photo is shown in Figure 1.

The contents of the seed particle dispersions (SD-1) to (SD-5) obtained in the above Synthesis Examples 8 to 12 were confirmed as shown in Table 2 below.

4. Synthesis of crosslinked resin microparticles Synthesis Example 13 (Synthesis of Crosslinked Resin Microparticles (Ba-1))

50 parts by mass of methyl methacrylate and 50 parts by mass of trimethylolpropane triacrylate "Aronix M-309" (trade name) manufactured by Toagosei Co., Ltd. were placed in a reaction vessel made of stainless steel, and the mixture was stirred and mixed. To the mixture, an aqueous emulsifier solution of 1.5 parts by mass of ethyl laurate sodium sulfate "Emael 2F-30" (trade name) dissolved in 100 parts by mass of ion-exchanged water and dissolved in an ion-exchanged water was used, and emulsified using an emulsifier. An emulsion of a vinyl monomer mixture is prepared.

In addition, 299 parts by mass of ion-exchanged water and 3.0 parts by mass of a 10% KOH aqueous solution were added to a glass reactor equipped with a mixer, a reflux condenser, a thermometer, a nitrogen gas introduction pipe, and a liquid supply pipe connection portion, and were produced in Synthesis Example 8. In a seed particle dispersion (SD-1), 285.7 parts by mass, the internal temperature of the reactor was adjusted to 20 ° C while stirring.

An emulsion of the above-mentioned vinyl monomer mixture was added to the reactor, and 2,2'-azobis(2,4-dimethylvaleronitrile) manufactured by Wako Pure Chemical Industries, Ltd. was added to the polymerization initiator (trade name). 1 part by mass of "V-65") was stirred at a reactor internal temperature of 20 ° C for 12 hours to absorb a vinyl monomer mixture and a polymerization initiator in the seed particles.

Then, nitrogen gas was blown into the reactor through a nitrogen introduction tube provided above the liquid surface, and the internal temperature was raised from 20 ° C to 70 ° C in 2 hours. Thereby, the vinyl monomer mixture absorbed in the seed particles was polymerized, and the internal temperature was maintained at 70 ° C for 2 hours. Next, triethylene glycol bis(3-(3-tert-butyl-4-hydroxy-5-methylphenyl)-propylate prepared by ADEKA as an antioxidant was added to 19 parts by mass of methanol in the reaction liquid. 1 part by mass of the acid ester "AO-70" (trade name, hereinafter referred to as "antioxidant"), and kept at 70 ° C for 30 minutes, and then cooled to produce a crosslinked resin fine particle (Ba-1). Dispersion.

The dispersion liquid of the crosslinked resin fine particles (Ba-1) is subjected to centrifugal separation treatment, and the supernatant liquid is removed, and a precipitated block of the crosslinked resin fine particles is recovered. The precipitated block of the recovered crosslinked resin fine particles (Ba-1) is mixed with ion-exchanged water of the same mass, redispersed, and then subjected to centrifugal separation treatment. Next, the supernatant liquid was removed until the recovered precipitate was heated at 155 ° C for 30 minutes, and the nonvolatile content was 98% by mass or more, and dried at 80 ° C. Thereafter, it was pulverized and the crosslinked resin fine particles (Ba-1) were recovered.

The SEM observation of the crosslinked resin fine particles (Ba-1) was carried out, and the number average particle diameter (dn) obtained by the image was 2.08 μm, the volume average particle diameter (dv) was 2.09 vm, and the volume average particle diameter (dv). The ratio (dv/dn) to the number average particle diameter (dn) is 1.00.

Further, when the cross-linking point equivalent of the crosslinked resin fine particles (Ba-1) was determined, it was 2.53 meq/g.

Synthesis Examples 14 to 16 (Synthesis of Crosslinked Resin Microparticles (Ba-2) to (Ba-4))

The composition of the monomer mixture absorbed in the seed particles of the seed particle dispersion (SD-1) was changed to that shown in Table 3, and the same operation as in Synthesis Example 13 was carried out to produce crosslinked resin fine particles (Ba-2). ~ (Ba-4).

The SEM observation of the crosslinked resin fine particles (Ba-2) to (Ba-4), the number average particle diameter (dn), the volume average particle diameter (dv), and the volume average particle diameter (dv) obtained by the image The ratio to the number average particle diameter (dn) (dv/dn) is shown in Table 3.

Further, when the cross-linking point equivalent of the crosslinked resin fine particles (Ba-2) to (Ba-4) was determined, the results are shown in Table 3.

Synthesis Example 17 (Synthesis of Crosslinked Resin Microparticles (Ba-5))

In addition to 285.7 parts by mass of the seed particle dispersion (SD-3) produced in Synthesis Example 10, 285.7 parts by mass of the seed particle dispersion (SD-1) of Synthesis Example 13 was substituted, and the vinyl monomer mixture absorbed in the seed particles was allowed to be used. The composition was changed to the same as in Synthesis Example 13, and the crosslinked resin fine particles (Ba-5) were produced.

The SEM observation of the crosslinked resin microparticles (Ba-5), the number average particle diameter (dn), the volume average particle diameter (dv), the volume average particle diameter (dv), and the number average particle diameter obtained by the image The ratio of (dn) (dv/dn) is shown in Table 3.

Further, when the cross-linking point equivalent of the crosslinked resin fine particles (Ba-5) was determined, the results are shown in Table 3.

Synthesis Examples 18 and 19 (Synthesis of Crosslinked Resin Microparticles (Ba-6) and (Ba-7))

In addition to 285.7 parts by mass of the seed particle dispersion (SD-4) produced in Synthesis Example 11, 285.7 parts by mass of the seed particle dispersion (SD-1) of Synthesis Example 13 was substituted, and the vinyl monomer mixture absorbed in the seed particles was allowed to be used. The composition was changed to the same as in Synthesis Example 13, and the crosslinked resin fine particles (Ba-6) and (Ba-7) were produced.

The SEM observation of the crosslinked resin fine particles (Ba-6) and (Ba-7), the number average particle diameter (dn), the volume average particle diameter (dv), and the volume average particle diameter (dv) obtained by the image The ratio to the number average particle diameter (dn) (dv/dn) is shown in Table 3.

Further, as shown in Table 3, the cross-linking point equivalents of the crosslinked resin fine particles (Ba-6) and (Ba-7) were determined.

Synthesis Examples 20 to 23 (Synthesis of Crosslinked Resin Microparticles (Ba-8) to (Ba-11))

The amount of ion-exchanged water used in Synthesis Example 13 was changed from 100 parts by mass to 125 parts by mass, and 454.6 parts by mass of the seed particle dispersion (SD-5) produced in Synthesis Example 12 was used instead of the seed particle dispersion (SD-1) 285.7. In the same manner as in Synthesis Example 13, except that the composition of the vinyl monomer mixture absorbed in the seed particles was changed to that shown in Table 4, the crosslinked resin fine particles (Ba-8) to (Ba-11) were produced. .

The SEM observation of the crosslinked resin fine particles (Ba-8) to (Ba-11), the number average particle diameter (dn), the volume average particle diameter (dv), and the volume average particle diameter (dv) obtained by the image The ratio to the number average particle diameter (dn) (dv/dn) is shown in Table 4.

Further, when the cross-linking point equivalent of the crosslinked resin fine particles (Ba-8) to (Ba-11) was determined, the results are shown in Table 4.

In addition, the crosslinked resin fine particles (Ba-9) obtained in Synthesis Example 21 were photographed by an electric field emission scanning electron microscope (FE-SEM) "JSM-6330F" (type name) of JEOL. The photo is shown in Figure 2.

Synthesis Example 24 (Synthesis of Crosslinked Resin Microparticles (Ba-12))

The amount of ion-exchanged water used in Synthesis Example 13 was changed from 100 parts by mass to 157 parts by mass, and 227.3 parts by mass of the seed particle dispersion (SD-5) produced in Synthesis Example 12 was used instead of the seed particle dispersion (SD-1) 285.7. The crosslinked resin fine particles (Ba-12) were produced in the same manner as in Synthesis Example 13 except that the composition of the vinyl monomer mixture absorbed in the seed particles was changed to that shown in Table 4.

The SEM observation of the crosslinked resin fine particles (Ba-12), the number average particle diameter (dn), the volume average particle diameter (dv), the volume average particle diameter (dv), and the number average particle diameter obtained by the image The ratio of (dn) (dv/dn) is shown in Table 4.

Further, when the cross-linking point equivalent of the crosslinked resin fine particles (Ba-12) was determined, the results are shown in Table 4.

Synthesis Example 25 (Synthesis of Crosslinked Resin Microparticles (Ba-13))

The amount of the ion-exchanged water of Synthesis Example 13 was changed from 100 parts by mass to 525 parts by mass, and the composition of the vinyl monomer mixture absorbed in the seed particles was changed as shown in Table 4, and the polymerization initiator was 2, 2'- The amount of use of azobis(2,4-dimethylvaleronitrile) (using V-65) was changed from 1 part by mass to 3 parts by mass, and the antioxidant of the synthesis example 13 and methanol were not added, and the synthesis example was carried out. 13 The same operation was carried out to produce crosslinked resin fine particles (Ba-13).

The SEM observation of the crosslinked resin fine particles (Ba-13), the number average particle diameter (dn), the volume average particle diameter (dv), the volume average particle diameter (dv), and the number average particle diameter obtained by the image The ratio of (dn) (dv/dn) is shown in Table 4.

Further, when the cross-linking point equivalent of the crosslinked resin fine particles (Ba-13) was determined, the results are shown in Table 4.

Synthesis Example 26 (Synthesis of Crosslinked Resin Microparticles (Ba-14))

The amount of ion-exchanged water used in Synthesis Example 13 was changed from 100 parts by mass to 125 parts by mass, and 454.6 parts by mass of the seed particle dispersion (SD-5) produced in Synthesis Example 12 was used instead of the seed particle dispersion (SD-1) 285.7. The crosslinked resin fine particles (Ba-14) were produced in the same manner as in Synthesis Example 13 except that the composition of the vinyl monomer mixture absorbed in the seed particles was changed to that shown in Table 4.

The SEM observation of the crosslinked resin fine particles (Ba-14), the number average particle diameter (dn), the volume average particle diameter (dv), the volume average particle diameter (dv), and the number average particle diameter obtained by the image The ratio of (dn) (dv/dn) is shown in Table 4.

Further, when the cross-linking point equivalent of the crosslinked resin fine particles (Ba-14) was determined, the results are shown in Table 4.

Synthesis Example 27 (Synthesis of Crosslinked Resin Microparticles (Ba-15))

The amount of the ion-exchanged water of the synthesis example 13 was changed from 100 parts by mass to 242.0 parts by mass, and the seed particle dispersion (SD-2) manufactured by the synthesis example 9 was used in place of the seed particle dispersion (SD-1) 285.7. The same operation as in Synthesis Example 13 was carried out to produce crosslinked resin fine particles (Ba-15).

The SEM observation of the crosslinked resin fine particles (Ba-15), the number average particle diameter (dn), the volume average particle diameter (dv), the volume average particle diameter (dv), and the number average particle diameter obtained by the image The ratio of (dn) (dv/dn) is shown in Table 4.

Further, when the cross-linking point equivalent of the crosslinked resin fine particles (Ba-15) was determined, the results are shown in Table 4.

Synthesis Example 28 (Synthesis of Crosslinked Resin Microparticles (Bb-1))

In a glass container provided with a liquid supply pipe by a quantitative pump, 269.4 parts by mass of methanol, 0.28 parts by mass of 25% ammonium water, and a polymer monomer aqueous solution (MM-2) 3.76 prepared in Synthesis Example 2 were added. The mass fraction was stirred to prepare a mixed solution (273.4 parts by mass).

Further, 174.7 parts by mass of ion-exchanged water, 323.2 parts by mass of methanol, and 0.28 parts by mass of 25% ammonium water were added to a glass reactor equipped with a stirrer, a reflux condenser, a thermometer, a nitrogen gas introduction pipe, and a liquid supply pipe connection portion. 3.76 parts by mass of the aqueous polymer monomer solution (MM-2) prepared in Synthesis Example 2, 50.0 parts by mass of methyl methacrylate, and 50.0 parts by mass of isobutyl methacrylate, and the reaction was carried out while blowing nitrogen gas under stirring. The internal temperature of the unit is adjusted to 50 °C.

After confirming that the temperature in the reactor was a stable value of 50 ° C, 10.0 parts by mass of trimethoxydecyl propyl methacrylate was added to the reactor. After 10 minutes, 2.4 parts by mass of 3-butyl peroxyacetate (using "Perbutyl PV") as a polymerization initiator was added to initiate polymerization. After confirming the addition of the polymerization initiator, the reaction solution was turbid, and gradually whitened to form a milky white color to form resin fine particles.

After the addition of the polymerization initiator, after 20 minutes passed, the aforementioned monomer mixture was supplied to the reactor. In other words, using a quantitative pump, 273.4 parts of the monomer mixture was supplied to the reactor at a rate of 60 minutes. After the completion of the supply, the temperature in the reactor was raised to 50 ° C in 160 minutes to prepare a dispersion of methacrylate-based resin fine particles having a hydrolyzable decyl group.

Four hours after the addition of the polymerization initiator, 32.85 parts by mass of 25% ammonium water which is a basic catalyst when a hydrolyzable alkylene group is added is added to the reaction liquid. Then, the internal temperature of the reactor was raised to 60 ° C, and the mixture was kept at the same temperature for 3 hours to carry out particle crosslinking. At this time, 1.0 part by mass of the antioxidant was added after 2.5 hours from the start of the addition of the ammonium water.

Next, the reaction solution was cooled and filtered through a 200 mesh deep layer filter (Polynet). Then, crosslinked resin fine particles (crosslinked alkyl methacrylate resin fine particles) are recovered. Thereafter, the nonvolatile matter was heated at 155 ° C for 30 minutes until the nonvolatile content reached 98% by mass or more, and dried at 60 ° C. Then, it was subjected to pulverization to obtain crosslinked resin fine particles (Bb-1).

The SEM observation of the crosslinked resin fine particles (Bb-1) was carried out, and the number average particle diameter (dn) obtained by the image was 1.06 μm, the volume average particle diameter (dv) was 1.08 μm, and the volume average particle diameter (dv). The ratio (dv/dn) to the number average particle diameter (dn) is 1.02.

Further, when the cross-linking point equivalent of the crosslinked resin fine particles (Bb-1) was determined, it was 1.06 meq/g as shown in Table 5.

Synthesis Examples 29 to 31 (Synthesis of Crosslinked Resin Microparticles (Bb-2) to (Bb-4))

The type and amount of the basic catalyst in the case where the hydrolyzable alkylene group was crosslinked were changed as shown in Table 5, and the operation of Synthesis Example 28 was carried out to produce an alkyl methacrylate resin. The resin fine particles (Bb-2) to (Bb-4) are crosslinked.

The SEM observation of the crosslinked resin fine particles (Bb-2) to (Bb-4), the number average particle diameter (dn), the volume average particle diameter (dv), and the volume average particle diameter (dv) obtained by the image The ratio to the number average particle diameter (dn) (dv/dn) is shown in Table 5.

Further, when the cross-linking point equivalent of the crosslinked resin fine particles (Bb-2) to (Bb-4) was determined, the results are shown in Table 5.

Synthesis Example 32 (Synthesis of Crosslinked Resin Microparticles (Bb-5))

The crosslinking resin fine particles (Bb-5) obtained from the alkyl methacrylate resin were produced by the operation of Synthesis Example 28 except that the amount of the addition of trimethoxy methoxyalkyl methacrylate was changed to 1.0 part by mass. .

The SEM observation of the crosslinked resin microparticles (Bb-5) was carried out, and the number average particle diameter (dn), volume average particle diameter (dv), volume average particle diameter (dv), and number average particle diameter obtained by the image were obtained by image. The ratio of (dn) (dv/dn) is shown in Table 5.

Further, when the cross-linking point equivalent of the crosslinked resin fine particles (Bb-5) was determined, the results are shown in Table 5.

Synthesis Example 33 (Synthesis of Crosslinked Resin Microparticles (Bb-6))

134.0 parts by mass of ion-exchanged water, 440.8 parts by mass of methanol, and 25% of ammonium water (for neutralization) of 0.50 mass were added to a glass reactor equipped with a mixer, a reflux condenser, a thermometer, a nitrogen gas introduction pipe, and a liquid supply pipe connection portion. And 6.76 parts by mass of the aqueous polymer monomer solution (MM-3) prepared in Synthesis Example 3, 40.0 parts by mass of methyl methacrylate and 50.0 parts by mass of isobutyl methacrylate, and nitrogen gas was blown while stirring. The internal temperature of the reactor was adjusted to 55 °C.

After confirming that the temperature in the reactor was a stable value of 55 ° C, 10.0 parts by mass of trimethoxydecyl propyl methacrylate was added to the reactor. After 10 minutes, 2.4 parts by mass of 3-butyl peroxyacetate (using "Perbutyl PV") as a polymerization initiator was added to initiate polymerization. After confirming the addition of the polymerization initiator, the reaction solution was turbid, and gradually whitened to form a milky white color to form resin fine particles.

Then, after the addition of the polymerization initiator, the internal temperature of the reaction liquid was maintained at 55 ° C for 4 hours, and the mixture was stirred to obtain a dispersion liquid of the resin fine particles having hydrolyzable alkylidene groups.

Then, 32.9 parts by mass of 25% ammonium water which is an alkaline catalyst when a hydrolyzable alkylene group is used is added to the reaction liquid. Then, the internal temperature of the reactor was raised to 68 ° C, and the mixture was kept at the same temperature for 3 hours to carry out particle crosslinking. At this time, 1.0 part by mass of an antioxidant was added after 2.5 hours from the start of the addition of the ammonium water.

Next, the reaction solution was cooled and filtered through a 200 mesh deep layer filter (Polynet). Then, crosslinked resin fine particles (crosslinked alkyl methacrylate resin fine particles) are recovered. Thereafter, the nonvolatile matter was heated at 155 ° C for 30 minutes until the nonvolatile content reached 98% by mass or more, and dried at 60 ° C. Then, it was subjected to pulverization to obtain crosslinked resin fine particles (Bb-6).

The SEM observation of the crosslinked resin microparticles (Bb-6) was carried out, and the number average particle diameter (dn), volume average particle diameter (dv), volume average particle diameter (dv), and number average particle diameter obtained by the image were obtained. The ratio of (dn) (dv/dn) is shown in Table 6.

Further, when the cross-linking point equivalent of the crosslinked resin fine particles (Bb-6) was determined, the results are shown in Table 6.

Synthesis Examples 34 to 38 (Synthesis of Crosslinked Resin Microparticles (Bb-7) to (Bb-11))

The polymer monomer liquid (MM-3) of Synthesis Example 33 was changed to the polymer monomer liquid (MM-4), (MM-5), and (MM-6) produced in Synthesis Examples 4 to 6, respectively. Further, the amount of the ion-exchanged water, the methanol, and the neutralized 25% ammonium water added to the reactor was as shown in Table 6, and the operation of Synthesis Example 33 was carried out to produce crosslinked resin fine particles (Bb-7) to ( Bb-11).

The SEM observation of the crosslinked resin fine particles (Bb-7) to (Bb-11), the number average particle diameter (dn), the volume average particle diameter (dv), and the volume average particle diameter (dv) obtained by the image The ratio to the number average particle diameter (dn) (dv/dn) is shown in Table 6.

Further, when the cross-linking point equivalent of the crosslinked resin fine particles (Bb-7) to (Bb-11) was determined, the results are shown in Table 6.

Furthermore, the crosslinked resin fine particles (Bb-7) obtained in Synthesis Example 34 were imaged by an electric field emission scanning electron microscope (FE-SEM) "JSM-6330F" (type name) manufactured by JEOL Ltd. The photo is shown in Figure 3.

Synthesis Example 39 (Synthesis of Crosslinked Resin Microparticles (Bb-12))

Except that the polymer monomer liquid (MM-3) of Synthesis Example 33 was changed to a polymer monomer liquid (MM-4), (MM-5), and (MM-6), and ions added to the reactor were added. The amount of the water, the methanol, and the neutralized amount of 25% ammonium water was adjusted as shown in Table 6, and the operation of Synthesis Example 33 was carried out to produce crosslinked resin fine particles (Bb-12).

The SEM observation of the crosslinked resin microparticles (Bb-12) was carried out, and the number average particle diameter (dn), volume average particle diameter (dv), volume average particle diameter (dv), and number average particle diameter obtained by the image were obtained. The ratio of (dn) (dv/dn) is shown in Table 6.

Further, when the cross-linking point equivalent of the crosslinked resin fine particles (Bb-12) was determined, the results are shown in Table 6.

Synthesis Examples 40 to 44 (Synthesis of Crosslinked Resin Microparticles (Bb-13) to (Bb-17))

Except that the polymer monomer liquid (MM-3) of Synthesis Example 33 was changed to a polymer monomer liquid (MM-3), (MM-4), and (MM-7), and ions added to the reactor were added. The amounts of 25% ammonium water exchanged for water, methanol, and neutralization were carried out in the same manner as in Synthesis Example 33 to produce crosslinked resin fine particles (Bb-13) to (Bb-17).

The SEM observation of the crosslinked resin fine particles (Bb-13) to (Bb-17), the number average particle diameter (dn), the volume average particle diameter (dv), and the volume average particle diameter (dv) obtained by the image The ratio to the number average particle diameter (dn) (dv/dn) is shown in Table 7.

Further, when the cross-linking point equivalents of the crosslinked resin fine particles (Bb-13) to (Bb-17) were determined, they are shown in Table 7.

Further, the crosslinked resin fine particles (Bb-14) obtained in Synthesis Example 41 and the crosslinked resin fine particles (Bb-16) obtained in Synthesis Example 43 were subjected to an electric field emission scanning electron microscope (FE-SEM) manufactured by JEOL. "JSM-6330F" (type name) photography. The photographs are shown in Figures 4 (Bb-14) and 5 (Bb-16).

Synthesis Examples 45 to 48 (Synthesis of Crosslinked Resin Microparticles (Bb-18) to (Bb-21))

Except that the polymer monomer liquid (MM-3) of Synthesis Example 33 was changed to a polymer monomer liquid (MM-5) and (MM-7), and ion-exchanged water, methanol, and the like were added to the reactor. The amount of 25% ammonium water for neutralization is as shown in Table 8, and the composition of the monomer is as shown in Table 8, and the operation of Synthesis Example 33 was carried out to produce crosslinked resin fine particles (Bb-18) to (Bb-21). .

The SEM observation of the crosslinked resin fine particles (Bb-18) to (Bb-21), the number average particle diameter (dn), the volume average particle diameter (dv), and the volume average particle diameter (dv) obtained by the image The ratio to the number average particle diameter (dn) (dv/dn) is shown in Table 8.

Further, when the cross-linking point equivalents of the crosslinked resin fine particles (Bb-18) to (Bb-21) were determined, they are shown in Table 8.

Furthermore, the crosslinked resin fine particles (Bb-19) obtained in Synthesis Example 46 were imaged by an electric field emission scanning electron microscope (FE-SEM) "JSM-6330F" (type name) manufactured by JEOL Ltd. The photo is shown in Figure 6.

5. Manufacture and evaluation of styrenic resin compositions

A styrene resin composition (SOLARENE GPPS G-116HV) (trade name) manufactured by Dongbu Hannong Chemicals was used to produce a styrene resin composition, and was evaluated. Further, the styrene resin is a polystyrene made of a styrene monomer, and has a refractive index of 1.59 measured at 25 ° C using light having a wavelength of 589 nm based on JIS K7015.

Example 1 (styrene resin composition and molded body)

After adding 1.2 g of the crosslinked resin fine particles (Ba-1) produced in Synthesis Example 13 to 58.8 g of the styrene resin, the blender "LABO PLASTOMILL" (trade name) manufactured by Toyo Seiki Seisakusho Co., Ltd. was used. The melt kneading treatment was carried out at ° C for 9 minutes (rotation speed 50 rpm). Then, it was taken out immediately, and it was pressed and extended, and it cut|disconnected, and the pellet-form styrene-resin composition was manufactured. The content of the crosslinked resin fine particles (Ba-1) was 2% by mass.

In the pellets of the styrene-based resin composition, a compression molding machine "SFA-37" (type name, manufactured by Shinto Metal Industry Co., Ltd.) having a mold (size: 120 mm in length, 120 mm in width, and 1.5 mm in thickness) was used. Compression molding was carried out under the conditions of a pressure of 5 MPa at 220 ° C to produce a flat shaped body. When the thickness of the molded body was measured using a micrometer, it was confirmed to be in the range of 1.50 mm ± 0.05 mm.

Regarding the molded body, the total light transmittance (%), the light diffusivity (%), and the yellowness (Yellow Index (YI)) were measured. The results are shown in Table 10.

Examples 2 to 13 (styrene resin composition and molded body)

The same operation as in the first embodiment was carried out except that the crosslinked resin fine particles (Ba-2) to (Ba-13) produced by the synthesis examples 14 to 25 were used instead of the crosslinked resin fine particles (Ba-1), and each of the pellets was produced. A styrene-based resin composition.

Then, using the pellets of the styrene resin composition, the same operation as in Example 1 was carried out to produce a flat molded body having a thickness of 1.50 mm ± 0.05 mm.

Regarding the molded body, the total light transmittance (%), the light diffusivity (%), and the yellowness (Yellow Index (YI)) were measured. The results are shown in Table 10.

Example 14 (styrene resin composition and molded body)

A pelletized styrene resin composition was produced in the same manner as in Example 1 except that 1.8 g of the crosslinked resin fine particles (Ba-7) produced in Synthesis Example 19 was added to 58.2 g of the styrene resin. The content of the crosslinked resin fine particles (Ba-7) was 3% by mass.

Using the pellets of the styrene resin composition, the same operation as in Example 1 was carried out to produce a flat molded body having a thickness of 1.50 mm ± 0.05 mm.

Regarding the molded body, the total light transmittance (%), the light diffusivity (%), and the yellowness (Yellow Index (YI)) were measured. The results are shown in Table 10.

Examples 15 and 16 (styrene resin composition and molded body)

The same operation as in Example 14 was carried out except that the crosslinked resin fine particles (Ba-9) and (Ba-12) produced by Synthesis Examples 21 and 24 were used instead of the crosslinked resin fine particles (Ba-7), and each of the pellets was produced. A styrene-based resin composition.

Then, using the pellets of the styrene resin composition described above, the same operation as in Example 14 was carried out to produce a flat molded body having a thickness of 1.50 mm ± 0.05 mm.

Regarding the molded body, the total light transmittance (%), the light diffusivity (%), and the yellowness (Yellow Index (YI)) were measured. The results are shown in Table 10.

Comparative Examples 1 to 2 (styrene resin composition and molded body)

The same operation as in the first embodiment was carried out except that the crosslinked resin fine particles (Ba-14) and (Ba-15) produced by the synthesis examples 26 and 27 were used instead of the crosslinked resin fine particles (Ba-1), and each of the pellets was produced. A styrene-based resin composition.

Then, using the pellets of the styrene resin composition, the same operation as in Example 1 was carried out to produce a flat molded body having a thickness of 1.50 mm ± 0.05 mm.

Regarding the molded body, the total light transmittance (%), the light diffusivity (%), and the yellowness (Yellow Index (YI)) were measured. The results are shown in Table 10.

Comparative Example 3 (styrene resin composition and molded body)

In addition to the use of cross-linked polymethyl methacrylate microparticles "GM-0806S" (trade name) (hereinafter referred to as "crosslinked resin microparticles (Bc-1)") manufactured by Ganz Chemical Co., in place of crosslinked resin microparticles (Ba- 1) The same operation as in the first embodiment was carried out, and each of the pelletized styrene resin compositions was produced.

Then, using the pellets of the styrene resin composition, the same operation as in Example 1 was carried out to produce a flat molded body having a thickness of 1.50 mm ± 0.05 mm.

Regarding the molded body, the total light transmittance (%), the light diffusivity (%), and the yellowness (Yellow Index (YI)) were measured. The results are shown in Table 10. Further, when the light diffusivity of the molded body is measured, the light diffusibility is too low, and the intensity of the parallel transmitted light on the light emitting surface is high. Therefore, the sensitivity of the detector is exceeded, and the light diffusivity cannot be measured.

The crosslinked resin fine particles (Bc-1) were imaged by an electric field emission scanning electron microscope (FE-SEM) "JSM-6330F" (type name) manufactured by JEOL Ltd. The photo is shown in Figure 7. Next, the ratio of the number average particle diameter (dn), the volume average particle diameter (dv), the volume average particle diameter (dv), and the number average particle diameter (dn) (dv/dn) is shown in Table 9.

Comparative Example 4 (styrene resin composition and molded body)

A pellet-like styrene resin composition was produced in the same manner as in Example 1 except that 1.8 g of the crosslinked resin fine particles (Bc-1) was added to 58.2 g of the styrene resin. The content of the crosslinked resin fine particles (Bc-1) was 3% by mass.

Using the pellets of the styrene resin composition, the same operation as in Example 1 was carried out to produce a flat molded body having a thickness of 1.50 mm ± 0.05 mm.

Regarding the molded body, the total light transmittance (%), the light diffusivity (%), and the yellowness (Yellow Index (YI)) were measured. The results are shown in Table 10.

Comparative Example 5 (styrene resin composition and molded body)

A pelletized styrene resin composition was produced in the same manner as in Example 1 except that 2.4 g of the crosslinked resin fine particles (Bc-1) was added to 57.6 g of the styrene resin. The content of the crosslinked resin fine particles (Bc-1) was 4% by mass.

Using the pellets of the styrene resin composition, the same operation as in Example 1 was carried out to produce a flat molded body having a thickness of 1.50 mm ± 0.05 mm.

Regarding the molded body, the total light transmittance (%), the light diffusivity (%), and the yellowness (Yellow Index (YI)) were measured. The results are shown in Table 10.

Comparative Example 6 (styrene resin composition and molded body)

In place of the crosslinked resin microparticles (Ba-), the crosslinked polymethyl methacrylate microparticle "MBX-5" (trade name) (hereinafter referred to as "crosslinked resin microparticles (Bc-2)") was used. 1) The same operation as in the first embodiment was carried out to produce a pellet-like styrene resin composition.

Then, using the pellets of the styrene resin composition, the same operation as in Example 1 was carried out to produce a flat molded body having a thickness of 1.50 mm ± 0.05 mm.

Regarding the molded body, the total light transmittance (%), the light diffusivity (%), and the yellowness (Yellow Index (YI)) were measured. The results are shown in Table 10.

a ratio (dv/dn) of the number average particle diameter (dn), volume average particle diameter (dv), volume average particle diameter (dv), and number average particle diameter (dn) of the crosslinked resin fine particles (Bc-2), As shown in Table 9.

Comparative Example 7

The same as in the first embodiment except that the resin fine particles "Tospearl 1110" (trade name) (hereinafter referred to as "crosslinked resin fine particles (Bc-3)") of Momentive Performance Materials were used instead of the crosslinked resin fine particles (Ba-1). The operation was carried out to produce a pellet-like styrene resin composition.

Then, using the pellets of the styrene resin composition, the same operation as in Example 1 was carried out to produce a flat molded body having a thickness of 1.50 mm ± 0.05 mm.

Regarding the molded body, the total light transmittance (%), the light diffusivity (%), and the yellowness (Yellow Index (YI)) were measured. The results are shown in Table 10. Further, when the light diffusivity of the molded body is measured, the light diffusibility is too low, and the intensity of the parallel transmitted light on the light emitting surface is excessively high. Therefore, the sensitivity of the detector is exceeded, and the light diffusivity cannot be measured.

The ratio of the number average particle diameter (dn), the volume average particle diameter (dv), the volume average particle diameter (dv), and the number average particle diameter (dn) of the crosslinked resin fine particles (Bc-3) (dv/dn), As shown in Table 9.

Comparative Example 8

A pellet-shaped molded body having a thickness of 1.50 mm ± 0.05 mm was produced by the same operation as in Example 1 except that the pellets composed only of the styrene resin were used without using the crosslinked resin fine particles.

Regarding the molded body, the total light transmittance (%), the light diffusivity (%), and the yellowness (Yellow Index (YI)) were measured. The results are shown in Table 10.

When a crosslinked resin fine particle containing a (meth)acrylate resin having excellent cost and weather resistance is used as a component of a light diffusing agent, when the light diffusing plate for a liquid crystal panel is formed, the content is 2 to 3 mass. % is generally preferably a total light transmittance of 50 to 70%, a light diffusivity of 75% or more, and a yellowness (YI value) of transmitted light of 20 or less.

As is clear from the results of Table 10, in Examples 1 to 16, the styrene resin composition to be used has the constitution of the present invention, and the obtained molded articles all have a total light transmittance in the range of 55% to 70%, and A light diffusivity of greater than 78%, and a yellowness (YI) of transmitted light of less than 19 degrees. These are properties suitable for a light diffusing plate or the like used for a liquid crystal panel or the like.

On the other hand, in Comparative Example 1, an example of a styrene-based resin composition containing crosslinked resin fine particles (Ba-14) which could not satisfy the requirement of setting the crosslinking point equivalent of 0.10 meq/g was used. In Comparative Example 1, the content of the obtained light-diffusing agent was 2% by mass, the light diffusivity was a low value of 58.2%, and the yellowness (YI) of the transmitted light was a high value of 38.3, which was not desirable.

Further, in Comparative Examples 2 to 7, the volume average particle diameter (dv) was more than 3 μm, and the crosslinked resin fine particles (Ba-15), (Bc-1), (Bc-2) or the like which did not satisfy the additive (2) were used. An example of the styrene resin composition of (Bc-3). Comparative Example 8 is an example of a composition containing no crosslinked resin particles. In Comparative Examples 2, 4, 5 and 6, the content of the light diffusing agent was 2 to 3% by mass, and the light diffusing ratio was as low as 73% or less, which was insufficient. Further, in Comparative Examples 3, 7 and 8, since the intensity of the parallel transmitted light was too high, the light diffusivity could not be measured.

Example 17 (styrene resin composition and molded body)

A pelletized styrene resin composition was produced in the same manner as in Example 1 except that 0.6 g of the crosslinked resin fine particles (Bb-1) produced in Synthesis Example 28 was added to 59.4 g of the styrene resin. The content of the crosslinked resin fine particles (Bb-1) was 1% by mass.

Then, using the pellets of the styrene resin composition, the same operation as in Example 1 was carried out to produce a flat molded body having a thickness of 1.50 mm ± 0.05 mm.

Regarding the molded body, the total light transmittance (%), the light diffusivity (%), and the yellowness (Yellow Index (YI)) were measured. The results are shown in Table 11.

Example 18 (styrene resin composition and molded body)

A pelletized styrene resin composition was produced in the same manner as in Example 1 except that 1.2 g of the crosslinked resin fine particles (Bb-1) was added to 58.8 g of the styrene resin. The content of the crosslinked resin fine particles (Bb-1) was 2% by mass.

Using the pellets of the styrene resin composition, the same operation as in Example 1 was carried out to produce a flat molded body having a thickness of 1.50 mm ± 0.05 mm.

Regarding the molded body, the total light transmittance (%), the light diffusivity (%), and the yellowness (Yellow Index (YI)) were measured. The results are shown in Table 11.

Example 19 (styrene resin composition and molded body)

A pelletized styrene resin composition was produced in the same manner as in Example 1 except that 1.8 g of the crosslinked resin fine particles (Bb-1) was added to 58.2 g of the styrene resin. The content of the crosslinked resin fine particles (Bb-1) was 3% by mass.

Using the pellets of the styrene resin composition, the same operation as in Example 1 was carried out to produce a flat molded body having a thickness of 1.50 mm ± 0.05 mm.

Regarding the molded body, the total light transmittance (%), the light diffusivity (%), and the yellowness (Yellow Index (YI)) were measured. The results are shown in Table 11.

Examples 20 to 22 (styrene resin composition and molded body)

The same operation as in Example 18 was carried out except that the crosslinked resin fine particles (Bb-2) to (Bb-4) produced in Synthesis Examples 29 to 31 were used instead of the crosslinked resin fine particles (Bb-1), and pellets were produced. A styrene-based resin composition.

Then, using the pellets of the styrene resin composition, the same operation as in Example 18 was carried out to produce a flat molded body having a thickness of 1.50 mm ± 0.05 mm.

Regarding the molded body, the total light transmittance (%), the light diffusivity (%), and the yellowness (Yellow Index (YI)) were measured. The results are shown in Table 11.

Comparative Example 9 (styrene resin composition and molded body)

The pelletized styrene resin composition was produced in the same manner as in Example 18 except that the crosslinked resin fine particles (Bb-5) produced in Synthesis Example 32 were used instead of the crosslinked resin fine particles (Bb-1).

Then, using the pellets of the styrene resin composition, the same operation as in Example 18 was carried out to produce a flat molded body having a thickness of 1.50 mm ± 0.05 mm.

Regarding the molded body, the total light transmittance (%), the light diffusivity (%), and the yellowness (Yellow Index (YI)) were measured. The results are shown in Table 11.

As is clear from the results of Table 11, in Examples 17 to 22, the styrene resin composition to be used has the constitution of the present invention, and the obtained molded articles all have a total light transmittance in the range of 55% to 70%, and More than 80% of the high light diffusivity, and less than 20% of the low transmitted light yellowness (YI). These have properties suitable for a light diffusing plate or the like used for a liquid crystal panel or the like.

On the other hand, Comparative Example 9 contains a styrene resin composition having a crosslinking point equivalent of less than 0.15 meq/g, which cannot be sufficiently crosslinked, and which cannot satisfy the crosslinked resin fine particles (Bb-5) of the requirement (b4). An example of a thing. In the molded article obtained from the styrene resin composition of Comparative Example 9, the intensity of the parallel transmitted light was too high, and the light diffusivity could not be measured, and the yellowness of the transmitted light was a high value of 30 or more (42.1), which was not desirable.

Examples 23 to 32 (styrene resin composition and molded body)

The same operation as in the first embodiment was carried out except that the crosslinked resin fine particles (Bb-6) to (Bb-15) produced in Synthesis Examples 33 to 42 were used instead of the crosslinked resin fine particles (Ba-1), and each of the pellets was produced. A styrene-based resin composition.

Then, using the pellets of the styrene resin composition, the same operation as in Example 18 was carried out to produce a flat molded body having a thickness of 1.50 mm ± 0.05 mm.

Regarding the molded body, the total light transmittance (%), the light diffusivity (%), and the yellowness (Yellow Index (YI)) were measured. The results are shown in Table 12.

Example 33 (styrene resin composition and molded body)

The pelletized styrene resin composition was produced in the same manner as in Example 24 except that the amounts of the styrene resin and the crosslinked resin fine particles (Bb-7) were each 59.4 g and 0.6 g.

Then, using the pellets of the styrene resin composition, the same operation as in Example 1 was carried out to produce a flat molded body having a thickness of 1.50 mm ± 0.05 mm.

Regarding the molded body, the total light transmittance (%), the light diffusivity (%), and the yellowness (Yellow Index (YI)) were measured. The results are shown in Table 12.

Example 34 (styrene resin composition and molded body)

A pellet-like styrene resin composition was produced in the same manner as in Example 24, except that the amounts of the styrene-based resin and the cross-linked resin fine particles (Bb-7) were each 58.2 g and 1.8 g.

Then, using the pellets of the styrene resin composition, the same operation as in Example 1 was carried out to produce a flat molded body having a thickness of 1.50 mm ± 0.05 mm.

Regarding the molded body, the total light transmittance (%), the light diffusivity (%), and the yellowness (Yellow Index (YI)) were measured. The results are shown in Table 12.

Example 35 (styrene resin composition and molded body)

The pelletized styrene resin composition was produced in the same manner as in Example 24 except that the amount of the styrene resin and the crosslinked resin fine particles (Bb-7) used was 57.9 g and 2.1 g, respectively.

Then, using the pellets of the styrene resin composition, the same operation as in Example 1 was carried out to produce a flat molded body having a thickness of 1.50 mm ± 0.05 mm.

Regarding the molded body, the total light transmittance (%), the light diffusivity (%), and the yellowness (Yellow Index (YI)) were measured. The results are shown in Table 12.

Example 36 (styrene resin composition and molded body)

The pelletized styrene resin composition was produced in the same manner as in Example 24 except that the amount of the styrene resin and the crosslinked resin fine particles (Bb-7) used was 56.7 g and 3.3 g, respectively.

Then, using the pellets of the styrene resin composition, the same operation as in Example 1 was carried out to produce a flat molded body having a thickness of 1.50 mm ± 0.05 mm.

Regarding the molded body, the total light transmittance (%), the light diffusivity (%), and the yellowness (Yellow Index (YI)) were measured. The results are shown in Table 12.

Comparative Examples 10 to 15 (styrene resin composition and molded body)

The same operation as in the first embodiment was carried out except that the crosslinked resin fine particles (Bb-16) to (Bb-21) produced in Synthesis Examples 43 to 48 were used instead of the crosslinked resin fine particles (Ba-1). A styrene-based resin composition.

Then, using the pellets of the styrene resin composition, the same operation as in Example 1 was carried out to produce a flat molded body having a thickness of 1.50 mm ± 0.05 mm.

Regarding the molded body, the total light transmittance (%), the light diffusivity (%), and the yellowness (Yellow Index (YI)) were measured. The results are shown in Table 12.

Further, in Comparative Example 12, when the light diffusivity of the molded body was measured, the light diffusibility was too low, and the intensity of the transmitted light in parallel with the light-emitting surface became high. Therefore, the sensitivity of the detector is exceeded, and the light diffusivity cannot be measured.

As is clear from the results of Table 12, Examples 23 to 32 and 34 to 35 have the constitution of the present invention by using the styrene resin composition, and the obtained molded articles all have a total light in the range of 55% to 65%. Transmittance, with a high light diffusivity of over 87%, and a low yellowness (YI) of 14% or less. These have properties suitable for a light diffusing plate or the like used for a liquid crystal panel or the like.

On the other hand, in Comparative Examples 10 to 13, the volume average particle diameter (dv) was less than 0.7 μm, and the crosslinked resin fine particles (Bb-16) and (Bb-17) which could not satisfy the requirement (b2) were contained. An example of a styrene resin composition of Bb-18) or (Bb-19). The molded article obtained from the styrene resin compositions of Comparative Examples 10 to 13 contained not only 2% by mass of the light diffusing agent but also a light diffusing rate of less than 80%, and the yellowness (YI) of the transmitted light was The high value of 24 or more, so it is not for the purpose.

Further, in Comparative Examples 14 and 15, a styrene resin composition containing crosslinked resin fine particles (Bb-20) or (Bb-21) which could not satisfy the above requirement (b3) was used, using (dv/dn) of more than 1.2. An example. The molded article obtained from the styrene resin compositions of Comparative Examples 14 and 15 contained not only 2% by mass of a light diffusing agent but also a light diffusing rate of less than 72%, and the yellowness (YI) of transmitted light was The high value of 31 or above is not an attempt.

[Industry use value]

By using the styrene resin composition of the present invention, melt molding or other molding processing can be performed under heating, and high light diffusibility can be obtained, and the diffused light can be excellent in permeability, and the light transmitted without light can be yellow. A molded body excellent in dimensional stability and shape stability. The styrene resin composition of the present invention and the molded article formed from the composition can activate the above-mentioned excellent characteristics, and can be effectively used for a light diffusing plate for a large display device such as a liquid crystal panel or a screen lens such as a transmissive screen. Optical applications such as lighting fixtures and lighting panels.

[Fig. 1] An image photographed by FE-SEM using the seed particle dispersion (SD-5) obtained in Synthesis Example 12.

[Fig. 2] An image photographed by FE-SEM of the crosslinked resin fine particles (Ba-9) obtained in Synthesis Example 21.

[Fig. 3] An image photographed by FE-SEM of the crosslinked resin fine particles (Bb-7) obtained in Synthesis Example 34.

[Fig. 4] An image photographed by FE-SEM of the crosslinked resin fine particles (Bb-14) obtained in Synthesis Example 41.

[Fig. 5] An image photographed by the crosslinked resin fine particles (Bb-16) obtained in Synthesis Example 43.

[Fig. 6] An image photographed by the crosslinked resin fine particles (Bb-19) obtained in Synthesis Example 46.

[Fig. 7] Image of FE-SEM photographed by cross-linked polymethyl methacrylate microparticle "GM-0806S" (trade name) manufactured by Ganz Chemical Co. as a crosslinked resin fine particle (Bc-1) .

Claims (6)

A styrene-based resin composition containing a styrene resin (A) having a content ratio of 80% by mass or more from a structural unit of a styrene-based monomer, based on 100% by mass of the total of all structural units a styrene resin composition obtained by crosslinking the resin fine particles (B) in an amount of 50% by mass or more based on 100% by mass of the total of the structural units, and the content of the structural unit derived from the (meth) acrylate. It is characterized in that the crosslinked resin fine particles (B) are crosslinked resin fine particles composed of a (meth) acrylate-based resin, and the volume average particle diameter (dv) is 0.7 to 2.5 μm, and the volume average particle diameter (dv) The ratio (dv/dn) to the number average particle diameter (dn) is 1.2 or less, and the crosslinking point equivalent is set to 0.15 meq/g or more, and the styrene resin (A) and the crosslinked resin fine particles (B) are The content ratio is 95.0 to 99.5% by mass and 0.5 to 5.0% by mass, respectively, when the total amount thereof is 100% by mass. The styrene resin composition of the first aspect of the invention, wherein the structure of the (meth) acrylate constituting the crosslinked resin fine particles (B) is 100% by mass based on the total amount of all the structural units. The content ratio of the unit is 80% by mass or more. The styrene resin composition according to claim 1 or 2, wherein the crosslinked resin fine particles (B) are the total amount of the structural unit derived from the monofunctional (meth) acrylate constituting the crosslinked resin fine particles. 100% by mass, comprising 60% by mass or more of a structural unit derived from methyl methacrylate and/or a structural sheet derived from isobutyl methacrylate Bit. The styrene resin composition according to claim 1 or 2, wherein the crosslinked resin fine particles (B) are seed particles of (meth)acrylate resin fine particles produced by a dispersion polymerization method. Crosslinked resin fine particles (Ba) obtained by absorbing ‧ polymerization of a vinyl monomer containing a crosslinkable monomer, and (meth) acrylate resin fine particles having hydrolyzable alkylene group produced by a dispersion polymerization method The crosslinked resin fine particles selected by cross-linking the obtained crosslinked resin fine particles (Bb). A molded article comprising a styrene resin composition according to any one of claims 1 to 4 for optical use. A molded article of the fifth aspect of the patent application is a light diffusing plate.