JP2012207215A - Resin particle, method for producing the same, and use thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a resin particle excellent in light-diffusing performance; a method for producing the same; and a use thereof.SOLUTION: This resin particle includes: a first polymer of crosslinked (meth)acrylic resin; and a second polymer derived from three kinds of monomers of a multifunctional vinyl monomer having two or more polymerizable carbon-carbon double bonds, a (meth)acrylate monomer having surface-active capacity and a monofunctional alkyl (meth)acrylate monomer (provided that the (meth)acrylate monomer having surface-active capacity is excluded). The first polymer and the second polymer is phase-separated. This resin particle has: a dispersion layer in the central part, wherein in the dispersion layer, a microphase-separation structure is formed where the first polymer phase exists in a state of dispersed particles with major axis of 1-200 nm; and at least one homogeneous layer outside the dispersion layer, the homogeneous layer comprising the first polymer or the second polymer.

Description

  The present invention relates to resin particles having light diffusion performance, a method for producing the resin particles, and uses of the resin particles (paints containing the resin particles, external preparations, resin compositions, light diffusion members, and light diffusion films). About.

  Resin particles having a particle size in the range of 1 to 100 μm and having a uniform size are used for spacers, slipperiness imparting agents, copier toners, paint matting agents, functional carriers, etc. In the liquid crystal field, it is also used as a raw material for light diffusing films and antiglare films.

  For example, a light diffusing film is manufactured by applying a mixture of resin particles in a binder and a solvent to the film, and the light diffusing performance is considered to be manifested by the irregular shape of the particles present on the film surface. Yes.

  In order to develop such light diffusion performance, various resin particles have been proposed.

  For example, Japanese Patent No. 4067694 (Patent Document 1) describes a matting agent for a soft film containing polymer particles having a multiphase structure, and a matting soft film containing the matting agent for a soft film. Yes. In the matting agent for a soft film disclosed in Patent Document 1, the polymer particles include a first-stage reaction that forms a rubbery polymer by suspension polymerization of a polymerizable monomer that forms a rubbery polymer, and then a glassy polymer. It is produced by a second-stage reaction in which a polymerizable monomer to be formed is added to form a glassy polymer by suspension polymerization.

  The polymer particles contained in the matting agent for a soft film disclosed in Patent Document 1 are a polymer formed by the first-stage reaction and a polymer formed by the second-stage reaction, which are present as different phases in one particle. It has a multiphase structure. In the polymer particles having such a multiphase structure, the polymer constituting each phase in the particles has a different light refractive index, so that the polymer particles having the multiphase structure have light diffusion performance.

Japanese Patent No. 4067694

  However, the polymer particles contained in the matting agent for soft film disclosed in Patent Document 1 have a multiphase structure inside, but the dispersion of the two polymers coexisting in the inside is not sufficient, specifically, Since each phase constituting the multiphase structure is large, it did not have sufficient light diffusion performance.

  For this reason, in the resin particle which has a multiphase structure inside, the improvement of light-diffusion performance was desired.

  This invention is made | formed in view of such a condition, Comprising: It aims at providing the resin particle excellent in light-diffusion performance, its manufacturing method, and its use.

  The inventor of the present invention adds three specific monomers to an aqueous emulsion in which specific seed particles (crosslinked (meth) acrylic resin particles) are dispersed, and causes the seed particles to absorb the three monomers. Thus, it was found that resin particles having excellent light diffusion performance can be obtained by polymerization, and the present invention has been completed.

  The resin particle according to the present invention is a resin particle having a multiphase structure, which is a polyfunctional vinyl having a first polymer that is a crosslinked (meth) acrylic resin and two or more polymerizable carbon-carbon double bonds. Monomer, following formula:

(Wherein R1 is H or CH ₃ , m is 0 to 50, and n is 0 to 50, provided that m + n> 1). And a second polymer derived from three monomers of a monofunctional alkyl (meth) acrylate monomer (excluding the (meth) acrylate monomer having the surface activity ability of the above formula),
The first polymer and the second polymer are phase-separated, and a dispersed layer in which a microphase-separated structure in which the phase of the first polymer is dispersed in the form of particles having a major axis of 1 to 200 nm is formed in the center. And having at least one homogeneous layer made of the first polymer or the second polymer outside the dispersion layer. In the present specification, “(meth) acryl” means “methacryl” or “acryl”, and “(meth) acrylate” means “methacrylate” or “acrylate”.

  The resin particles of the present invention have a special internal structure (fine phase separation structure = micro phase separation structure) in which a first polymer that is a crosslinked (meth) acrylic resin and a second polymer derived from three types of monomers coexist. ) Is formed at the center, and at least one homogeneous layer made of the first polymer or the second polymer is provided outside the dispersion layer. Thus, since the resin particles of the present invention are in a state where materials having different optical refractive indexes (that is, the first polymer and the second polymer) are mixed, excellent light diffusion that cannot be obtained with conventional resin particles. It is considered that the performance is exhibited. The resin particles of the present invention have at least one homogeneous layer made of a first polymer that is a crosslinked (meth) acrylic resin or a second polymer derived from three types of monomers, on the outside of the dispersion layer. Since the surface of the resin particles is constituted by such a homogeneous layer, there is no fusion between particles in dehydration and drying during production, and when used as a light diffusing agent (matting agent) for a soft film It is easy to disperse during kneading, and while maintaining flexibility, toughness and texture, it is possible to obtain a transparent and matte film without whitening or strength reduction during bending or stretching. . The soft texture of the film is thought to be due to the fact that a microphase separation structure is formed at the center of the resin particles and the core of the resin particles is soft.

  The method for producing resin particles of the present invention is a crosslinked (meth) acrylic type as seed particles in the presence of a polymerization initiator under a temperature condition of (10-hour half-life temperature T-10 ° C. of the polymerization initiator) or higher. A polyfunctional vinyl monomer having two or more polymerizable carbon-carbon double bonds in an aqueous emulsion in which resin particles are dispersed;

(Wherein R1 is H or CH ₃ , m is 0 to 50, and n is 0 to 50, provided that m + n> 1) and a (meth) acrylate monomer having a surface active ability represented by Three types of monomers of monofunctional alkyl (meth) acrylate monomer (excluding the (meth) acrylate monomer having surface active ability of the above formula) are added, and the three types of the above-mentioned crosslinked (meth) acrylic resin particles are added Polymerization is performed while absorbing the monomer to obtain resin particles.

  According to the method for producing resin particles of the present invention, as described above, the resin particles of the present invention having excellent light diffusion performance can be produced.

  The paint of the present invention includes the resin particles of the present invention.

  According to the coating material of the present invention, since the resin particles of the present invention are included, a coating film excellent in light diffusion performance can be obtained.

  The external preparation of the present invention includes the resin particles of the present invention.

  According to the external preparation of the present invention, since it contains the resin particles of the present invention, skin defects such as spots and freckles can be corrected by the light diffusion effect of the resin particles.

  The resin composition of the present invention includes the resin particles of the present invention.

  According to the resin composition of the present invention, since the resin particles of the present invention are included, a molded article having light diffusion performance (that is, a light diffusion member) can be obtained.

  The light diffusing member of the present invention includes the resin particles of the present invention.

  Since the light diffusion member of the present invention includes the resin particles of the present invention, the light diffusion member is excellent in light diffusion performance.

  The light-diffusion film of this invention is equipped with the surface layer formed from the resin composition for surface layers containing 10-500 weight part of resin particles of this invention, and 100 weight part of binder resin, It is characterized by the above-mentioned.

  Since the light diffusion film of the present invention includes the resin particles of the present invention, the light diffusion performance is excellent.

  ADVANTAGE OF THE INVENTION According to this invention, the resin particle excellent in the light-diffusion performance and its manufacturing method can be provided. Furthermore, the coating material, external preparation, resin composition, light-diffusion member, and light-diffusion film containing the resin particle excellent in the light-diffusion performance can be provided.

It is the schematic which shows an example of the internal structure of the resin particle of this invention. It is the (a) scanning electron microscope (SEM) photograph and (b) transmission electron microscope (TEM) photograph of the resin particle of manufacture example 1. It is the (a) scanning electron microscope (SEM) photograph and (b) transmission electron microscope (TEM) photograph of the resin particle of the comparative manufacture example 1. 6 is a transmission electron microscope (TEM) photograph of resin particles of Comparative Production Example 3.

[Resin particles of the present invention]
The resin particles of the present invention are resin particles having a multiphase structure, and are a first polymer that is a crosslinked (meth) acrylic resin, a polyfunctional vinyl monomer, a (meth) acrylate monomer having a specific surface active ability, and And a second polymer derived from three types of monomers, which are monofunctional alkyl (meth) acrylate monomers (excluding the (meth) acrylate monomer having surface-active ability). The cross-linked (meth) acrylic resin and the three types of monomers will be described in detail in the section of the method for producing resin particles of the present invention described later.

  In the resin particles of the present invention, the first polymer, which is the crosslinked (meth) acrylic resin, and the second polymer derived from the three types of monomers are phase-separated, and the phase of the first polymer has a major axis of 1 to A homogenous layer comprising a dispersion layer (inner layer) in which a microphase separation structure existing in a state of being dispersed in 200 nm particles is formed, and comprising the first polymer or the second polymer outside the dispersion layer It has at least one layer (surface layer).

  In the present specification, the “micro phase separation structure” means that two or more kinds of polymers are phase-separated in a mixture containing two or more kinds of polymers, and the phase of at least one of these polymers is 200 nm or less in major axis The structure which exists in the state disperse | distributed to the particle form (fine dispersion). That is, the “microphase separation structure” is not a homogeneous structure in which a state (coarse dispersion) including a large dispersed phase in which the major axis of the phase exceeds 200 nm and / or an aggregated phase in which a plurality of phases are aggregated or a phase separation is not observed. .

  The resin particles of the present invention may have, for example, the internal structure shown in FIG. The resin particles having the internal structure shown in FIG. 1 have a dispersion layer 1 as an inner layer and two homogeneous layers 2 and 3 as surface layers.

  The dispersion layer 1 is present in the center of the resin particle, and includes a first polymer phase 11 that is the crosslinked (meth) acrylic resin and a second polymer phase 12 derived from the three types of monomers. Yes. In the dispersion layer 1, the phase of the first polymer 11 exists in a state of being dispersed in the form of particles. The major axis T3 of the phase 11 of the first polymer in the dispersion layer 1 is in the range of 1 nm to 200 nm, and the dispersion layer 1 has a microphase separation structure.

  In addition, the resin particles shown in FIG. 1 include, on the outside of the dispersion layer 1, in order from the dispersion layer 1 side, the homogeneous layer 2 made of the second polymer derived from the three types of monomers, and the crosslinked (meth) acrylic resin. And a homogeneous layer 3 made of the first polymer. The surface layer is constituted by these two homogeneous layers 2 and 3. Here, the thickness T2 of the homogeneous layer 2 is 0.25 to 0.40 μm, and the thickness T1 of the homogeneous layer 3 is 0.03 to 0.05 μm. In the present specification, “homogeneous layer” means a layer having a homogeneous structure in which phase separation is not observed.

  Furthermore, the resin particle shown in FIG. 1 has a convex part on the surface. In the resin particle having such a convex portion on the surface, the maximum value of the convex portion thickness T4 is preferably 1/100 to 1/10 times the major axis R of the resin particle. Such surface protrusions further improve the light diffusion performance of the resin particles.

The internal structure of the resin particles as described above can be confirmed, for example, by observing the cross section of the particles with a transmission electron microscope (TEM) such as Model H-7600 manufactured by Hitachi High-Technologies Corporation. As a pretreatment method for observation, for example, a method in which resin particles are embedded in an epoxy resin, cut into a thin film slice, and stained with ruthenium tetroxide (RuO ₄ ) can be mentioned.

  Further, whether or not the major axis T3 of the phase 11 of the first polymer which is a crosslinked (meth) acrylic resin in the dispersion layer 1 is in the range of 1 to 200 nm is determined by, for example, resin particles using a transmission electron microscope (TEM). This can be determined by taking a cross-sectional photograph of the particle including the center of the particle and measuring the longest diameter T3 of the phase 11 of the first polymer that is the largest in the dispersion layer 1.

  In addition, the thicknesses T1 and T2 of the homogeneous layers 2 and 3 (surface layers) can be measured, for example, by taking a cross-sectional photograph of the particle including the center of the resin particle with a transmission electron microscope (TEM), and at any eight locations on the outer periphery of the resin particle. It can obtain | require as an average value of the measured thickness.

  The resin particles of the present invention preferably have a volume average particle diameter in the range of 2 to 100 μm. A more preferable volume average particle diameter is in the range of 4 to 90 μm. When the volume average particle diameter of the resin particles is less than 2 μm, the light transmittance may be lowered. On the other hand, if it exceeds 100 μm, the light diffusion performance may be insufficient.

[Method for Producing Resin Particles of the Present Invention]
The method for producing resin particles of the present invention is a crosslinked (meth) acrylic type as seed particles in the presence of a polymerization initiator under a temperature condition of (10-hour half-life temperature T-10 ° C. of the polymerization initiator) or higher. In an aqueous emulsion in which resin particles are dispersed, a polyfunctional vinyl monomer, a (meth) acrylate monomer having a specific surface activity and a monofunctional alkyl (meth) acrylate monomer (however, the (meth) acrylate monomer having the surface activity) 3) monomers are added, and the crosslinked (meth) acrylic resin particles are polymerized while absorbing the three types of monomers to obtain resin particles.

  That is, the resin particles of the present invention are specific to an aqueous emulsion (emulsion) containing specific crosslinked polymer particles (crosslinked (meth) acrylic resin particles) as seed particles (core particles) in the presence of a polymerization initiator. It can be produced by adding the three kinds of monomers and polymerizing the seed particles while absorbing the three kinds of monomers.

  Below, about the manufacturing method of the resin particle of this invention, the manufacturing process (1st process) of the bridge | crosslinking (meth) acrylic-type resin particle as a seed particle, the preparation process of the aqueous emulsion in which the mixture of the said 3 types of monomer was disperse | distributed ( The second step) and the polymerization step (third step) in which the crosslinked (meth) acrylic resin particles are polymerized while absorbing the three types of monomers will be described in more detail. Is not limited.

  In the present specification, “aqueous emulsion” means a suspension of seed particles or monomer components in an aqueous medium such as water, and the concentration thereof is such that the polymerization reaction is not inhibited. For example, seed particles or monomer components are about 0.5 to 500 g / l in the aqueous medium.

(1) First Step The seed particles produced in the first step are particles (crosslinked (meth) acrylic resin particles) made of a crosslinked (meth) acrylic resin and are also called core particles.

  The seed particles preferably have a volume average particle diameter of 1.5 to 90 μm. When the volume average particle diameter of the seed particles is less than 1.5 μm, the seed particles may be agglomerated when polymerizing the seed particles while absorbing the three types of monomers in the third step described later. There is a possibility that a microphase separation structure is not formed inside the resin particles. On the other hand, if it exceeds 90 μm, the three kinds of monomers may not be sufficiently absorbed by the seed particles. A more preferable volume average particle diameter is 3 to 80 μm. The method for measuring the volume average particle diameter of the particles will be described in detail in Examples.

  Although it does not specifically limit as said bridge | crosslinking (meth) acrylic-type resin particle, In this invention, the monofunctional alkyl (meta) used by the 2nd process mentioned later from the point of the solvent resistance of a seed particle, a dispersibility, and a cohesiveness. Resin particles having a structure in which an acrylate monomer is crosslinked with a polyfunctional vinyl monomer are preferred.

  Examples of the monofunctional alkyl (meth) acrylate monomer that forms the crosslinked (meth) acrylic resin particles (excluding the (meth) acrylate monomer having the surface active ability of the formula described later) include, for example, methyl acrylate, methacryl Methyl acid, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, tertiary butyl acrylate, tertiary butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate , Stearyl acrylate, stearyl methacrylate and the like. Of these, butyl acrylate, butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, tertiary butyl acrylate, and tertiary butyl methacrylate are preferred. These may be used individually by 1 type, or may use 2 or more types together.

  As the polyfunctional vinyl monomer that forms the crosslinked (meth) acrylic resin particles, those having two or more polymerizable carbon-carbon double bonds can be used, such as divinylbenzene, divinylnaphthalene, and the like. Aromatic divinyl compounds such as derivatives thereof, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol diacrylate, trimethylolpropane triacrylate, diethylenic carboxylic acid esters such as allyl methacrylate, N, N-divinylaniline, divinyl ether, Examples thereof include divinyl compounds such as divinyl sulfite and compounds having three or more vinyl groups. These may be used individually by 1 type, or may use 2 or more types together.

  When the crosslinked (meth) acrylic resin particles are resin particles having a structure in which a monofunctional (meth) acrylate monomer is crosslinked with a polyfunctional vinyl monomer, the monofunctional alkyl in the crosslinked (meth) acrylic resin particles The weight ratio of the structural unit derived from the (meth) acrylate monomer and the structural unit derived from the polyfunctional vinyl monomer is preferably 1: 0.01 to 0.5, more preferably 1: 0.02 to 0.4. . When the weight ratio of the structural unit derived from the polyfunctional vinyl monomer to the structural unit derived from the monofunctional alkyl (meth) acrylate monomer is less than 0.01, the crosslinked (meth) acrylic resin particles are bonded together. There is a risk that. On the other hand, when the weight ratio of the structural unit derived from the polyfunctional vinyl monomer to the structural unit derived from the monofunctional alkyl (meth) acrylate monomer exceeds 0.5, the specific three types of monomers are used in the third step. There is a possibility that the crosslinked (meth) acrylic resin particles may not be sufficiently absorbed, and the special structure of the present invention in the third step (specifically, a structure having a dispersion layer in which a microphase separation structure is formed). The resin particles may not be obtained.

  The crosslinked (meth) acrylic resin particles can be produced by a known method. However, in the production of the resin particles of the present invention, crosslinking is carried out by suspension polymerization in terms of ease of particle diameter adjustment. It is particularly preferable to produce (meth) acrylic resin particles. Specifically, after further adding a surfactant and a polymerization inhibitor to a dispersed phase obtained by adding a suspension stabilizer to water, a monomer and a polymerization initiator for forming the above-mentioned crosslinked (meth) acrylic resin particles are added. In addition, it is preferable to produce crosslinked (meth) acrylic resin particles by stirring at high speed and polymerizing the above monomer in the state of an aqueous emulsion.

  The polymerization temperature and time may be appropriately set depending on the material to be used, the polymerization conditions, etc.

  As the suspension stabilizer (dispersion stabilizer) used in the first step, a dispersion stabilizer generally used for polymer suspension polymerization, for example, a water-soluble polymer such as methyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol; Examples include poorly water-soluble inorganic salts such as calcium phosphate, magnesium hydroxide, magnesium pyrophosphate, barium sulfate, calcium carbonate, and silica. The amount used may be appropriately set depending on the material used, polymerization conditions, and the like, and is, for example, about 10 to 60 parts by weight with respect to 100 parts by weight of the monomer forming the crosslinked (meth) acrylic resin particles.

  Examples of the surfactant used in the first step include sodium lauryl sulfate, sodium dodecylbenzene sulfonate, and sodium α-olefin sulfonate. When an inorganic dispersant is used as the suspension stabilizer, it is preferable to use a suspension stabilizer (inorganic dispersant) and a surfactant in combination from the viewpoint of dispersion stability and particle size adjustment. What is necessary is just to set suitably the usage-amount of surfactant according to the material to be used, polymerization conditions, etc. For example, 0.1-20.0 weight with respect to 100 weight part of monomers which form the said bridge | crosslinking (meth) acrylic-type resin particle. About a part.

  Examples of the polymerization inhibitor used in the first step include water-soluble ones such as nitrites, sulfites, hydroquinones, ascorbic acids, water-soluble vitamin Bs, citric acid, and polyphenols. In addition, these polymerization inhibitors may be used individually by 1 type, or may use 2 or more types together.

  As the polymerization initiator used in the first step, for example, a conventionally known polymerization initiator that is widely used for the polymerization of acrylic resin monomers can be used. For example, benzoyl peroxide, lauroyl peroxide, orthochlorobenzoyl peroxide, orthomethoxybenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, t-butylperoxy-2-ethylhexanoate, di-t- Examples thereof include organic peroxides such as butyl peroxide, azo compounds such as azobisisobutyronitrile, azobiscyclohexacarbonitrile, and azobis (2,4-dimethylvaleronitrile). In addition, these polymerization initiators may be used individually by 1 type, or may use 2 or more types together. What is necessary is just to set suitably the usage-amount of a polymerization initiator by the material to be used, polymerization conditions, etc. For example, about 0.01-5 weight part with respect to 100 weight part of monomers which form the said bridge | crosslinking (meth) acrylic-type resin particle. It is.

  In the production of the crosslinked (meth) acrylic resin particles in the first step, the suspension polymerization is preferably performed in the presence of a mercaptan chain transfer agent. By performing suspension polymerization in the presence of a mercaptan chain transfer agent, a special structure of the present invention (specifically, a structure having a dispersed layer in which a microphase separation structure is formed) is formed in a third step described later. The resin particle which has can be obtained efficiently.

Examples of mercaptan chain transfer agents include n-octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, 2-hydroxyethyl mercaptan, lauryl mercaptan, stearyl mercaptan and the like, α-methylstyrene dimer (CH ₂ = CPhCH ₂ C (CH ₃ ) ₂ Ph [where Ph is a phenyl group]). In addition, these mercaptan chain transfer agents may be used individually by 1 type, or may use 2 or more types together. The amount of the mercaptan chain transfer agent used is 0.05 to 100 parts by weight with respect to 100 parts by weight of monomers (that is, monofunctional alkyl (meth) acrylate monomer and polyfunctional vinyl monomer) that form the crosslinked (meth) acrylic resin particles. The amount is 15 parts by weight, preferably 0.1 to 10 parts by weight. When the amount of the mercaptan chain transfer agent used is less than 0.05 parts by weight with respect to 100 parts by weight of the monomer forming the crosslinked (meth) acrylic resin particles, the crosslinked (meth) acryl obtained by polymerization The molecular chain of the resin-based resin particles becomes too long, and there is a possibility that the specific three types of monomers are not easily absorbed by the crosslinked (meth) acrylic resin particles. Resin particles having a structure (specifically, a structure having a dispersed layer in which a microphase separation structure is formed) may be difficult to obtain. On the other hand, when the amount of the mercaptan chain transfer agent used exceeds 15 parts by weight with respect to 100 parts by weight of the monomer forming the crosslinked (meth) acrylic resin particles, formation of crosslinked (meth) acrylic resin particles It takes time to complete the polymerization of the monomer, and the productivity may decrease.

(2) Second Step In this second step, an aqueous emulsion of three types of monomers is prepared. Specifically, a surfactant, three types of monomers, and a polymerization initiator are added to water and stirred at a high speed to obtain an aqueous emulsion.

  The three types of monomers used in the second step are a monofunctional alkyl (meth) acrylate monomer, a polyfunctional vinyl monomer, and a (meth) acrylate monomer having surface activity. Here, the polymerization initiator is preferably dissolved in the above three monomers and then suspended in water.

  As the monofunctional alkyl (meth) acrylate monomer used in the second step (excluding the (meth) acrylate monomer having the surface activity ability of the formula described later), in the description of the first step, the crosslinking (meth) Alkyl (meth) acrylate monomers exemplified as monomers for forming acrylic resin particles, for example, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, isobutyl acrylate, methacrylic acid Examples include isobutyl, tertiary butyl acrylate, tertiary butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, stearyl acrylate, and stearyl methacrylate. These may be used individually by 1 type, or may use 2 or more types together.

  “Polyfunctional” of a polyfunctional vinyl monomer means having two or more polymerizable carbon-carbon double bonds, that is, containing two or more vinyl groups in one molecule.

  As the polyfunctional vinyl monomer used in the second step, the polyfunctional vinyl monomer exemplified as the monomer for forming the crosslinked (meth) acrylic resin particles in the description of the first step, for example, divinylbenzene, divinylnaphthalene and Aromatic divinyl compounds such as their derivatives, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol diacrylate, diethylenic carboxylic acid esters such as trimethylolpropane triacrylate, N, N-divinylaniline, divinyl ether, divinylsulfate And divinyl compounds such as phyto, and compounds having three or more vinyl groups. These may be used individually by 1 type, or may use 2 or more types together.

  The (meth) acrylate monomer having surface activity used in the second step has the following formula:

(Where R1 is H or CH ₃ , m is 0 to 50, and n is 0 to 50, provided that m + n> 1). “Having surfactant ability” means that the (meth) acrylate monomer of the above formula has a surfactant function.

A commercially available product can be used as the (meth) acrylate monomer having the surface activity represented by the above formula. As a commercial item of the (meth) acrylate monomer which has surface active ability represented by the said formula, the "Blenmer (trademark)" series by NOF Corporation is mentioned, for example. Further, in the “Blemmer (registered trademark)” series, “Blemmer (registered trademark) 50 PEP-300” which is one of poly (ethylene glycol-propylene glycol) monomethacrylate (a plurality of types represented by the above formula). A mixture of compounds wherein R is CH ₃ , m averages about 3.5 and n averages about 2.5) and poly (ethylene glycol-propylene glycol) ) "Blemmer (registered trademark) 70PEP-350B" which is one kind of monomethacrylate (a mixture of a plurality of compounds represented by the above formula, wherein R is CH ₃ , m is about 5 on average) And n having an average of about 2) is suitable for the present invention. These may be used individually by 1 type, or may use 2 or more types together.

  The weight ratio A: B: C between the monofunctional alkyl (meth) acrylate monomer [A] and the polyfunctional vinyl monomer [B] used in the second step and the (meth) acrylate monomer [C] having surface activity is 1: 0.03-1.5: 0.001-0.5 is preferred.

  When the amount of the polyfunctional vinyl monomer [B] used is less than 0.03 parts by weight relative to the amount of the monofunctional alkyl (meth) acrylate monomer [A] used by 1 part by weight, the resin particles obtained are used as a solvent. When the paint is mixed and the resin particles are dissolved in the solvent, the resin particles do not play a role as a paint additive (paint matting agent (paint light diffusing agent)) in the paint. There is. On the other hand, when the amount of the polyfunctional vinyl monomer [B] used exceeds 1.5 parts by weight with respect to 1 part by weight of the monofunctional alkyl (meth) acrylate monomer [A], the resin particles obtained When there are no convex portions on the surface, or when the hardness of the obtained resin particles is increased and the resin particles are contained in the coating, other members may be damaged. The range of the more preferable usage-amount of polyfunctional vinyl monomer [B] is 0.1-1.2 weight part with respect to 1 weight part of usage-amount of monofunctional alkyl (meth) acrylate monomer [A].

  In addition, when the amount of the (meth) acrylate monomer [C] having surface active ability is less than 0.001 part by weight with respect to 1 part by weight of the monofunctional alkyl (meth) acrylate monomer [A], it can be obtained. The inside of the obtained resin particles may not have a fine phase separation structure (micro phase separation structure), and a shape having a convex portion which is a preferable surface shape of the resin particles may not be obtained. On the other hand, when the amount of the (meth) acrylate monomer [C] having surface active ability exceeds 0.3 parts by weight with respect to 1 part by weight of the monofunctional alkyl (meth) acrylate monomer [A], Polymerization stability may deteriorate, and a large amount of aggregates may be generated. The range of the use amount of the (meth) acrylate monomer [C] having a more preferable surface active ability is 0.01 to 0.2 with respect to 1 part by weight of the use amount of the monofunctional alkyl (meth) acrylate monomer [A]. It is.

  Examples of the surfactant used in the second step include those exemplified in the first step. Further, the amount of the surfactant used may be appropriately set depending on the material to be used and the polymerization conditions. For example, three types of monomers (that is, monofunctional alkyl (meth) acrylate monomer, polyfunctional vinyl monomer, and surface active ability) (Meth) acrylate monomer) having a content of about 0.1 to 20 parts by weight and about 0.01 to 5.0 parts by weight with respect to 100 parts by weight.

  Examples of the polymerization initiator used in the second step include those exemplified in the first step. The amount of the polymerization initiator may be appropriately set depending on the material to be used and the polymerization conditions. For example, three types of monomers (that is, a monofunctional alkyl (meth) acrylate monomer, a polyfunctional vinyl monomer, and a surface active ability are determined). (Meth) acrylate monomer) is about 0.1 to 20 parts by weight and about 0.01 to 5.0 parts by weight with respect to 100 parts by weight.

(3) Third Step In the third step, the crosslinked (meth) acrylic resin particles obtained in the first step are polymerized while absorbing the above-mentioned three kinds of monomers in a specific proportion, and the above-described present invention is performed. Resin particles are obtained. Specifically, an aqueous emulsion of three kinds of monomers in a specific ratio obtained in the second step containing a polymerization initiator is dropped into the aqueous emulsion of the crosslinked (meth) acrylic resin particles obtained in the first step. Then, the three kinds of monomers are polymerized while the three kinds of monomers are absorbed by the crosslinked (meth) acrylic resin particles. That is, in the presence of a polymerization initiator, the three kinds of monomers are added to an aqueous emulsion of crosslinked (meth) acrylic resin particles, and then the three kinds of monomers are added to the crosslinked (meth) acrylic resin particles. Polymerize while absorbing monomer.

  After polymerization, the obtained resin particles are separated and recovered through post-treatment by a known method.

  The temperature at the time of dropping (adding) the aqueous emulsion of the three monomers is 10 hours half-life temperature T-10 of (the polymerization initiator (polymerization initiator contained in the aqueous emulsion of the three monomers)). ℃) or more, preferably (10-hour half-life temperature T-10 ℃ of the polymerization initiator) to (10-hour half-life temperature T ℃ of the polymerization initiator), (10 of the polymerization initiator 10). It is more preferable that it is (time half-life temperature T-10 degreeC)-(10-hour half-life temperature T-4 degreeC).

  In addition, after dropping (adding) the aqueous emulsion of the three monomers, the temperature at which the crosslinked (meth) acrylic resin particles are polymerized while absorbing the three monomers is set to (the polymerization initiator (the 3 10-hour half-life temperature T-10 ° C. of polymerization initiator contained in aqueous emulsion of seed monomer) or more, (10-hour half-life temperature T-10 ° C. of polymerization initiator) to (initiation of polymerization) It is preferably 10 hours half-life temperature T ° C of the agent, and more preferably (10 hours half-life temperature T-10 ° C of the polymerization initiator) to (10 hours half-life temperature T-3 ° C). .

  For example, when azobisisobutyronitrile is used as a polymerization initiator, its 10-hour half-life temperature is 64 ° C., and is a crosslinked (meth) acrylic resin particle having a temperature of 54 ° C. or higher (more preferably 55-60 ° C.). The emulsion of the three types of monomers is dropped into the aqueous emulsion of (seed particles), and then the crosslinked (meth) acrylic resin particles are added to the crosslinked (meth) acrylic resin particles under a temperature condition of 54 ° C. or higher (more preferably 55 to 61 ° C.). Polymerization is performed while absorbing the three types of monomers.

  The polymerization time may be appropriately set depending on the material used, polymerization conditions, etc., and is, for example, about 2 to 5 hours.

  In the third step, the three kinds of monomers are crosslinked (meth) acrylic resin at an addition rate in the range of 3 to 50 g / min with respect to 100 g of the crosslinked (meth) acrylic resin particles obtained in the first step. It is preferably added to the aqueous emulsion of particles. When the addition rate of the three types of monomers is less than 3 g / min with respect to 100 g of the crosslinked (meth) acrylic resin particles, the addition rate is too slow and the predetermined amount of the three types of monomers is crosslinked (meth) acrylic. Before being absorbed by the resin particles, the state of the crosslinked (meth) acrylic resin particles may change, and the crosslinked (meth) acrylic resin particles may not be able to absorb a predetermined amount of the three types of monomers. As a result, polymerization may occur with the three types of monomers alone that are not absorbed by the crosslinked (meth) acrylic resin particles, and a microphase separation structure may not be formed inside the resulting resin particles. On the other hand, when the addition rate of the three types of monomers exceeds 50 g / min with respect to 100 g of the crosslinked (meth) acrylic resin particles, the addition rate is too high and the added three types of monomers are crosslinked (meth). Before being absorbed by the acrylic resin particles, the three types of monomers may be polymerized alone, and a microphase separation structure may not be formed inside the resulting resin particles.

  The weight ratio of the crosslinked (meth) acrylic resin particles used in the third step to the three kinds of monomers is preferably 1: 0.4 to 1.0. When the amount of the three kinds of monomers used is less than 0.4 parts by weight based on 1 part by weight of the crosslinked (meth) acrylic resin particles, the amount of the crosslinked (meth) acrylic resin particles is too large. There is a possibility that resin particles having a special particle structure (specifically, a structure having a dispersed layer in which a microphase separation structure is formed) may not be obtained. On the other hand, when the amount of the three types of monomers used exceeds 1.0 part by weight with respect to 1 part by weight of the crosslinked (meth) acrylic resin particles, the amount of the three types of monomers with respect to the crosslinked (meth) acrylic resin particles Since there is too much quantity, there exists a possibility that all the said monomers may not be absorbed by the said bridge | crosslinking (meth) acrylic-type resin particle, and the monomer which could not be absorbed may polymerize independently. The weight ratio between the crosslinked (meth) acrylic resin particles and the three monomers is more preferably 1: 0.5 to 1.0.

  By adjusting the compatibility between the crosslinked (meth) acrylic resin particles and the three types of monomers, that is, the absorption of the three types of monomers into the crosslinked (meth) acrylic resin particles that are the seed particles, a phase separation reaction is performed. Then, a volumetric shrinkage occurs, and a dispersion layer (inner layer) having a fine phase separation structure (microphase separation structure) is formed inside the resin particles, and the polymer or cross-link ( A surface layer composed of at least one homogeneous layer made of (meth) acrylic resin particles is formed. The surface layer thickness (total thickness of all layers outside the dispersion layer) of the resin particles obtained by the production method of the present invention is approximately 1/200 to 1/10 of the particle size (volume average particle size) of the resin particles. It is.

〔paint〕
The paint of the present invention contains the resin particles of the present invention.

  The paint of the present invention preferably contains a resin binder. Examples of the resin binder include (meth) acrylic ester resins (acrylic resins), polycarbonate resins, polyester resins, urethane resins, epoxy resins, polypropylene resins, silicone resins, styrene resins, and fluorine resins. Various polymers capable of forming a film, such as resins, cellulose resins, other vinyl resins (vinyl chloride resins, etc.), modified products thereof, precursors of these polymers (monomers, oligomers) Or a mixture thereof). These resin binders may be dissolved in a solvent or may exist as an emulsion in the solvent, and are appropriately selected according to the purpose of use.

  As a form of the paint of the present invention, a liquid paint in which a solid resin binder is dissolved in a solvent and resin particles are dispersed in the solvent; a liquid paint in which solid resin binder and resin particles are dispersed in the solvent; Powder paint containing solid resin binder and resin particles and not containing solvent; Liquid paint containing liquid resin binder and no solvent; Liquid paint obtained by diluting liquid resin binder with solvent .

  As the liquid resin binder, for example, a polymer precursor (monomer, oligomer, or mixture thereof) capable of ultraviolet curing and electron beam curing can be used. In this case, in the paint, It is preferable to contain a photopolymerization initiator. Specific examples of the photopolymerization initiator to be contained in the paint include acetophenones, benzophenones, thioxanthones, Michler benzoylbenzoate, α-amyloxime ester, thioxanthones, propiophenones, benzyls, benzoin (Benzoin, benzoin methyl ether, etc.), acylphosphine oxides, aromatic diazonium salts, aromatic sulfonium salts, aromatic iodonium salts, metallocene compounds, benzoin sulfonic acid esters and the like.

  The solvent used as necessary in the coating material of the present invention can be appropriately selected depending on the properties of the film formed by the resin particles and the resin binder. Usually, water, alcohols (ethyl alcohol, methyl alcohol, Isopropyl alcohol, propylene glycol monomethyl ether, etc.), esters (ethyl acetate, isopropyl acetate, butyl acetate, etc.), ketones (acetone, methyl ethyl ketone [MEK], methyl isobutyl ketone), ethers (cellosolve, butylcellosolve), terpenes (Tarpentin, Dipenten) and the like.

  In the paint of the present invention, as an auxiliary agent for enhancing the paintability and the performance of the coating film, an organic or inorganic ultraviolet absorber, a dispersant, a surfactant, an anti-settling agent, a wetting agent, an anti-sagging agent, An antifoaming agent, antioxidant, etc. can be mix | blended with a proper quantity as needed. Further, extender pigments, colored pigments, dyes, and the like can be added to the paint of the present invention.

The organic ultraviolet absorber is not particularly limited, and examples thereof include benzophenone ultraviolet absorbers such as 2-hydroxy-4-methoxy-5-sulfobenzophenone; 2,2′-methylenebis [4- ( 1,1,3,3-tetramethylbutyl) -6- [2H-
Benzotriazol-2-yl] phenol]] (“ADEKA STAB (registered trademark) LA-31” manufactured by ADEKA Corporation), 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy- Benzotriazole ultraviolet absorbers such as 5-t-butylphenyl) benzotriazole and 2- (2-hydroxy-3-5-dit-butylphenyl) -5-chlorobenzotriazole; hydroxyphenyltriazine ultraviolet absorbers; salicylic acid UV absorbers such as pt-butylphenyl salicylate and p-octylphenyl salicylate; 2-ethylhexyl-2-cyano-3,3-diphenyl acrylate, ethyl-2-cyano-3,3-diphenyl acrylate, etc. Use of cyanoacrylate UV absorbers, etc. Kill. The organic ultraviolet absorber is preferably 0.01 to 2.0 parts by weight, more preferably 0.03 to 2.0 parts by weight, and still more preferably 0 to 100 parts by weight of the resin binder in the paint. When included in a proportion of 0.05 to 1.0 part by weight, sufficient ultraviolet absorptivity can be imparted to the paint.

  Examples of the inorganic ultraviolet absorber include inorganic fine particles such as zinc oxide fine particles, titanium oxide fine particles, cerium oxide fine particles, zirconium oxide fine particles (particle diameter is 0.003 to 0.1 μm, preferably 0.003 to 0.05 μm). Particles) can be used. When the inorganic ultraviolet absorber is contained in the paint in a proportion of 0.001 to 24% by weight, sufficient ultraviolet absorptivity can be imparted to the paint. The inorganic ultraviolet absorber may be included in the resin particles at a ratio of 1 to 80% by weight. These ultraviolet absorbers may be used alone or in admixture of two or more.

  The paint has fluidity that can be made uniform, and the solid content needs to be integrated by curing the resin binder. Therefore, the components that form the coating film in the paint (components excluding the solvent, that is, components) In the case where the resin binder is solid, the content of the resin particles in the solid content) is preferably 95% by weight or less. When the content of the resin particles in the component forming the coating film in the coating exceeds 95% by weight, the coating film becomes extremely brittle. Moreover, it is preferable that content of the resin particle in the component which forms the coating film in the said coating material is 0.5 weight% or more. Thereby, the matte effect by a resin particle can fully be acquired.

[External preparation]
The resin particles of the present invention can be used as a raw material for external preparations. The external preparation of the present invention contains the resin particles of the present invention. Although content of the resin particle in an external preparation can be suitably set according to the kind of external preparation, it exists in the range of 1-80 weight%, and it is more preferable that it exists in the range of 5-70 weight%. When the content of the resin particles with respect to the total amount of the external preparation is less than 1% by weight, a clear effect due to the inclusion of the resin particles may not be recognized. On the other hand, when the content of the resin particles exceeds 80% by weight, a remarkable effect commensurate with the increase in the content may not be recognized, which is not preferable in terms of production cost.

  Examples of external preparations include cosmetics (cosmetics) and external medicines.

  The cosmetic is not particularly limited as long as it has an effect due to the inclusion of the resin particles. For example, liquids such as pre-shave lotion, body lotion, lotion, cream, emulsion, body shampoo, antiperspirant, etc. Cosmetics; soaps, scrubs, and other cosmetics; packs; shaving creams; funerals; foundations; lipsticks; lip balms; blushers; eyebrows cosmetics; nail polish cosmetics; hair-washing cosmetics; Examples include aromatic cosmetics; toothpaste; bath preparations; sunscreen products; suntan products; body powders such as body powders and baby powders.

  The topical pharmaceutical is not particularly limited as long as it is applied to the skin, and examples thereof include pharmaceutical creams, ointments, pharmaceutical emulsions, and pharmaceutical lotions.

  Moreover, the main agent or additive generally used can be mix | blended with these external preparations according to the objective in the range which does not impair the effect of this invention. Examples of such main agents or additives include water, lower alcohols (alcohols having 5 or less carbon atoms), oils and fats, hydrocarbons (such as petroleum jelly and liquid paraffin), and higher fatty acids (such as stearic acid having 12 carbon atoms). Fatty acids), higher alcohols (alcohols having 6 or more carbon atoms such as cetyl alcohol), sterols, fatty acid esters (octyldodecyl myristate, oleate, etc.), metal soaps, moisturizers, surfactants (polyethylene glycol, etc.) , Polymer compounds, clay minerals (components having several functions such as extender pigments and adsorbents; talc, mica, etc.), coloring materials (red iron oxide, yellow iron oxide, black iron oxide, etc.), perfume , Antiseptic / disinfectant, antioxidant, UV absorber, acrylic resin particles (poly (meth) acrylic acid ester particles), silicon System particles, resin particles such as polystyrene particles, organic-inorganic composite particles, pH modifiers (triethanolamine), a special formulation additives, pharmaceutical active ingredients, and the like.

(Resin composition)
The resin composition of the present invention contains the resin particles of the present invention.

  The resin composition of the present invention preferably further contains a base resin. Since the resin composition of the present invention further including a base resin has light diffusing performance, it can be used as a light diffusing resin composition for molding a light diffusing member such as a light diffusing plate.

  Examples of the base resin include polycarbonate resins; vinyl chloride resins such as polyvinyl chloride and vinyl chloride-vinylidene chloride copolymers; vinyl ester resins such as polyvinyl acetate and vinyl acetate-ethylene copolymers; Polystyrene (styrene resin such as polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer, styrene-butadiene block copolymer, styrene-isoprene block copolymer, styrene-methyl methacrylate copolymer; (Meth) acrylic acid ester, (meth) acrylic acid ester-acrylonitrile copolymer, (meth) acrylic acid ester-based resin such as (meth) acrylic acid ester-styrene copolymer; condensate of terephthalic acid and ethylene glycol, Adipic acid and ethylene glycol Polyester resins such as condensates with polyethylene; Polyolefin resins such as polyethylene, polypropylene, chlorinated polyethylene, chlorinated polypropylene, carboxyl-modified polyethylene, polyisobutylene, and polybutadiene; urethane resins; epoxy resins; silicone resins; Examples thereof include resins. These base resin may be used independently and may use 2 or more types together.

  As the polycarbonate resin, for example, an aromatic polycarbonate resin obtained by reacting an aromatic dihydroxy compound and phosgene or a carbonic acid diester by a melting method or a solution method can be used.

  Examples of the aromatic dihydroxy compound include 2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, and 2,2-bis (4 -Hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) octane, 2,2-bis (4-hydroxyphenyl) phenylmethane, 2,2-bis (4-hydroxy-1-methylphenyl) propane, Bis (4-hydroxyphenyl) naphthylmethane, 1,1-bis (4-hydroxy-t-butylphenyl) propane, 2,2-bis (4-hydroxy-3-bromophenyl) propane, 2,2-bis ( 4-hydroxy-3,5-tetramethylphenyl) propane, 2,2-bis (4-hydroxy-3-chlorophenyl) propyl Bis (hydroxyaryl) alkanes such as bread, 2,2-bis (4-hydroxy-3,5-tetrachlorophenyl) propane, 2,2-bis (4-hydroxy-3,5-tetrabromophenyl) propane; 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,5,5-trimethylcyclohexane, etc. Bis (hydroxyaryl) cycloalkanes; Dihydroxyaryl ethers such as 4,4′-dihydroxyphenyl ether and 4,4′-dihydroxy-3,3′-dimethylphenyl ether; 4,4′-dihydroxydiphenyl sulfide 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfide Droxydiaryl sulfides; dihydroxydiaryl sulfoxides such as 4,4′-dihydroxydiphenyl sulfoxide, 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfoxide; 4,4′-dihydroxydiphenyl sulfone, 4,4 ′ -Dihydroxy diaryl sulfones such as dihydroxy-3,3'-dimethyldiphenyl sulfone; and dihydroxy diphenyls such as 4,4'-dihydroxydiphenyl.

  These aromatic dihydroxy compounds may be used alone or in combination of two or more. In addition, the aromatic dihydroxy compound may contain an arbitrary substituent or the like as long as it does not affect desired physical properties, and may be crosslinked with a crosslinking agent or the like. As the aromatic dihydroxy compound, 2,2-bis (4-hydroxyphenyl) propane [bisphenol A] is preferable because a resin composition having excellent impact resistance can be obtained. In the resin composition of the present invention, two or more polycarbonate resins may be used.

  In general, the resin particles are preferably added in an amount of 0.1 to 30% by weight based on the resin composition. If the addition amount of the resin particles is less than 0.1% by weight, it becomes difficult to obtain a desired effect (for example, a light diffusion effect) by the resin particles, and if the addition amount of the resin particles exceeds 30% by weight, the resin particles Is not uniformly dispersed in the resin composition, and in this case as well, it is difficult to obtain a desired effect (for example, a light diffusion effect) by the resin particles.

  The resin composition of the present invention can also contain various components such as a fluorescent brightening agent, a heat stabilizer, and an organic or inorganic ultraviolet absorber. These various components can give the resin composition physical properties such as desired fluorescent whitening, thermal stability, and ultraviolet absorption. Examples of the compound that can be used as the UV absorber and the preferable range of the blending amount of the UV absorber are the same as those of the UV absorber that is used as necessary in the paint described in the section of the paint.

  The fluorescent brightening agent is not particularly limited, and for example, an oxazole fluorescent brightening agent (for example, “Kayalite (registered trademark) OS” manufactured by Nippon Kayaku Co., Ltd.), an imidazole fluorescent brightening agent. Rhodamine fluorescent whitening agents and the like can be used. Such fluorescent brightening agent is preferably 0.0005 to 0.1 parts by weight, more preferably 0.001 to 0.1 parts by weight, and more preferably 0.001 to 0.1 parts by weight with respect to 100 parts by weight of the base resin in the resin composition. When it is preferably contained in a proportion of 0.001 to 0.05 parts by weight, sufficient fluorescent whitening property can be imparted to the resin composition.

  The heat stabilizer is not particularly limited, and examples thereof include organic phosphorus heat stabilizers such as phosphate esters, phosphite esters, and phosphonate esters; hindered phenol heat stabilizers; lactone heat stabilizers. An phosphite antioxidant (for example, “ADEKA STAB (registered trademark) PEP-36” manufactured by ADEKA Corporation) having a function of suppressing thermal oxidation can be used. Such a heat stabilizer is preferably 0.005 to 0.5 part by weight, more preferably 0.01 to 0.5 part by weight, and further preferably 100 parts by weight of the base resin in the resin composition. Can be imparted with sufficient thermal stability to the resin composition.

(Light diffusion member)
The light diffusion member of the present invention includes the resin particles of the present invention. The light diffusing member of the present invention can be obtained, for example, by molding the resin composition of the present invention. As a molding method of the resin composition, from the viewpoint of productivity, a pellet-shaped resin composition is molded by a molding method such as injection molding, injection compression molding, or extrusion molding, and a molded body (light diffusion member) is formed. The method of obtaining can be adopted. Further, a method is adopted in which a resin composition is extruded to obtain a sheet-like molded body, and this sheet-like molded body is molded by a molding method such as vacuum molding or pressure molding to obtain a molded body (light diffusion member). be able to.

  The light diffusing member of the present invention includes electrical and electronic parts such as lighting covers, automobile parts such as automotive interior panels, machine parts, packaging films for packaging miscellaneous goods, foods and medicines, foods and medicines, etc. It can also be used as a building such as a container, fiber, board or roof.

  In addition, the light diffusing member of the present invention includes, as necessary, plasticizers, stabilizers, antioxidants, flame retardants, antistatic agents, lubricants, high additives as auxiliary agents for enhancing weather resistance and processing performance. An appropriate amount of a molecular modifier or the like can be blended as necessary. In addition, extender pigments, colored pigments, dyes, and the like can be added to the light diffusing member.

[Light diffusion film]
The resin particles of the present invention can be contained in a light diffusion film as a light diffusing agent. The light-diffusion film of this invention is equipped with the surface layer formed from the resin composition for surface layers containing 10-500 weight part of resin particles of this invention, and 100 weight part of binder resin, It is characterized by the above-mentioned.

  The binder resin contained in the resin composition for a surface layer is not particularly limited as long as it is a resin capable of preparing the resin composition for a surface layer, and specific examples include the binder resin exemplified in the description of the paint. Can do. For example, in the examples described later, an acrylic binder (acrylic resin) is used.

  The light diffusing film of the present invention is prepared, for example, by mixing the resin particles of the present invention, a binder resin, a solvent and the like by a known method to prepare a dispersion, which is then formed on a film serving as a substrate by a known method. It can be manufactured by coating and drying. In addition, the solvent used for manufacture of the light-diffusion film of this invention is not specifically limited, As a specific example, the solvent illustrated in description of the said coating material can be mentioned.

  Hereinafter, the present invention will be specifically described with reference to production examples, comparative production examples, examples, and comparative examples, but the present invention is not limited to these production examples and examples.

  First, a method for measuring the volume average particle diameter and variation coefficient of resin particles and the haze of a light diffusion film will be described.

[Method for measuring volume average particle diameter of resin particles and coefficient of variation of particle diameter]
The volume average particle diameter (arithmetic average diameter in the volume-based particle size distribution) and the coefficient of variation (CV value) of the particle diameter are measured using a Coulter Multisizer III (Beckman Coulter, Inc. measuring device). In this measurement, calibration is performed using an aperture having a size suitable for the particle diameter of the particle to be measured according to Reference MANUAL FOR THE COUNT MULTISIZER (1987) issued by Coulter Electronics Limited.

  Specifically, 0.1 g of resin particles are predispersed in 10 ml of 0.1% nonionic surfactant using a touch mixer and ultrasonic waves to obtain a dispersion. Next, the dispersion was dropped into a beaker filled with ISOTON (registered trademark) II (manufactured by Beckman Coulter, Inc .: electrolyte for measurement) attached to the body of Coulter Multisizer III with a dropper while gently stirring, and Coulter Multi Adjust the densitometer reading on the sizer screen to about 10%. Next, the size of the aperture (diameter), current (aperture current), gain (gain), and polarity (polarity of the inner electrode) are input to the Coulter Multisizer III main body according to Reference MANUAL FORTHE COUNTER SIZE MULTIRIZER 198 issued by Coulter Electronics Limited. Then, the volume-based particle size distribution is measured under a predetermined condition according to the aperture size. During the measurement, the beaker is gently stirred to the extent that bubbles do not enter, and the measurement ends when the particle size distribution of 100,000 particles is measured. The measured volume-weighted average diameter of 100,000 particles (arithmetic average diameter in volume% mode: volume median diameter) is calculated as the volume average particle diameter (X) of the resin particles.

  The size of the aperture used in this measurement is 20 μm for resin particles having a volume average particle diameter of less than 1 μm, 50 μm for resin particles having a volume average particle diameter of less than 1 to 10 μm, and the volume average particle diameter is Resin particles having a pore diameter of 100 μm for resin particles of less than 10 to 30 μm and a pore diameter of 280 μm for resin particles having a volume average particle diameter of more than 30 to less than 90 μm and a volume average particle diameter of more than 90 μm In contrast, the pore diameter is 400 μm.

  Further, the coefficient of variation (CV value) of the particle diameter of the resin particles is expressed by the following formula using the standard deviation (σ) of the volume-based particle size distribution of the resin particles and the volume average particle diameter (X) of the resin particles. calculate.

CV value (%) = (σ / X) × 100
[Measurement method of haze]
The haze of the light diffusing film is measured according to JIS K7136, specifically, using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., model: NDH-2000).

[Production Example 1: Production of resin particles]
[First step]
An autoclave having an internal volume of 5 L was charged with 2400 g of water and 164 g of magnesium pyrophosphate as a suspension stabilizer to obtain a dispersed phase. To this dispersed phase, 0.84 g of sodium lauryl sulfate as a surfactant and 0.24 g of sodium nitrite as a polymerization inhibitor were further added.

  Subsequently, 732 g of isobutyl methacrylate, 12 g of allyl methacrylate, 12 g of ethylene glycol dimethacrylate, 12 g of benzoyl peroxide as a polymerization initiator and 15 g of octyl mercaptan as a mercaptan chain transfer agent were mixed in the dispersed phase.

  The obtained mixture was stirred at a rotational speed of 7500 rpm for 10 minutes using a high-speed stirrer (manufactured by Primics Co., Ltd. (formerly Special Machinery Corporation), model: TK homomixer) to obtain an emulsion.

  The obtained emulsion was reacted at 70 ° C. for 3 hours to obtain an emulsion of a first reaction polymer (crosslinked (meth) acrylic resin particles serving as seed particles) having a volume average particle size of 7.4 μm. Hereinafter, “aqueous emulsion” is also simply referred to as “emulsion”.

[Second step]
To a stainless steel beaker with an internal volume of 2 L, 432 g of water and 0.05 g of sodium lauryl sulfate as a surfactant are added, and 398.4 g of methyl methacrylate as a monofunctional alkyl (meth) acrylate monomer [A], polyfunctional vinyl 14 g of ethylene glycol dimethacrylate as monomer [B] (0.04 parts by weight with respect to 1 part by weight of methyl methacrylate), poly (ethylene glycol-propylene glycol) as (meth) acrylate monomer [C] having surface-active ability ) Monomethacrylate (manufactured by NOF Corporation, product name: BLEMMER (registered trademark) 50PEP-300, a mixture composed of a plurality of types of compounds represented by the above formula, wherein R is CH ₃ , m is average About 3.5 and n is about 2.5 on average) 21.7 g Methacrylic 0.05 parts by weight to methyl 1 part by weight) and azobisisobutyronitrile (10 hours half-life temperature 64 ° C. as a polymerization initiator) was added to 4.8 g, they were mixed together.

  The obtained mixture was stirred for 10 minutes at a rotational speed of 7500 rpm using the above high-speed stirrer to obtain an emulsion. The total amount of monomers used in the second step (that is, methyl methacrylate, ethylene glycol dimethacrylate, and poly (ethylene glycol-propylene glycol) monomethacrylate) is 434.1 g, and this amount Is the total (756 g) of the amount used of the monomers (ie, isobutyl methacrylate, allyl methacrylate, and ethylene glycol dimethacrylate) used in the production of the crosslinked (meth) acrylic resin particles (seed particles) in the first step. This corresponds to 0.57 times the weight.

[Third step]
The emulsion of the first reaction polymer (cross-linked (meth) acrylic resin particles as seed particles) obtained in the first step in the autoclave is cooled to 60 ° C., and the first reaction polymer (cross-linked (meth)). The emulsion obtained in the second step was continuously dropped into the emulsion of (acrylic resin particles) over 10 minutes. After completion of the dropping, a polymerization reaction was performed at 60 ° C. for 4 hours. Thereafter, 0.3 g of sulfamic acid and 6.3 g of linear alkylbenzene sulfonic acid soda were added, the temperature was raised to 100 ° C., and the reaction was continued at this temperature for 1 hour. Next, after cooling to 30 ° C. and adding hydrochloric acid to decompose magnesium pyrophosphate, washing and dehydration are carried out, followed by drying at 60 ° C. in a vacuum dryer to obtain resin particles having a volume average particle size of 8.6 μm. Obtained.

  Moreover, the obtained resin particle was imaged with the scanning electron microscope (SEM), and the SEM image of Fig.2 (a) was obtained. Further, the obtained resin particles were embedded in an epoxy resin, cut into a thin film section (thickness 90 nm), stained with ruthenium tetroxide, and the cross section was imaged with a transmission electron microscope (TEM). A TEM image of (b) was obtained. From the SEM image shown in FIG. 2 (a) and the TEM image shown in FIG. 2 (b), the resin particles obtained in this Production Example 1 are the dispersion layer 1 shown in FIG. It was confirmed that it had a convex part on the surface of the said resin particle.

  Specifically, from the TEM image shown in FIG. 2 (b), the center of the resin particles obtained in Production Example 1 is a crosslinked (meth) acrylic resin (crosslinked (meta) produced in the first step. ) First polymer (derived from acrylic resin particles) (black portion in FIG. 2 (b) showing that it was dyed with a dye) and three types of monomers (monofunctional alkyl (meth) acrylate monomer [A], A second polymer derived from the polyfunctional vinyl monomer [B] and the (meth) acrylate monomer [C] having surface-active ability) (the gray part in FIG. 2 (b) showing that it is not dyed with a stain); Phase separated and the phase of the first polymer (cross-linked (meth) acrylic resin black part in FIG. 2 (b) showing dyed with a dyeing agent) dispersed in the form of particles Dispersion layer with separation structure (Fig. 1) It was observed corresponding to the layer 1 layer) is provided. The major axis of the phase of the first polymer (black portion in FIG. 2 (b) showing that it is dyed with a staining agent) that is a crosslinked (meth) acrylic resin in the dispersion layer of the resin particles obtained in Production Example 1 The maximum value of the length corresponding to T3 in FIG. 1 was measured based on the TEM image in FIG.

  Further, from the TEM image shown in FIG. 2 (b), the second polymer derived from the three types of monomers (not dyed with the staining agent) is outside the dispersion layer in which the microphase separation structure is formed. 2 (b) shown in FIG. 2 (b), a homogeneous layer (corresponding to the dispersion layer 2 in FIG. 1) is formed, outside the homogeneous layer made of the second polymer derived from these three types of monomers. Is a homogeneous layer (a layer corresponding to the dispersion layer 3 in FIG. 1) composed of a first polymer (a black portion in FIG. 2 (b) showing that it is dyed with a dyeing agent) which is a crosslinked (meth) acrylic resin. ) Was observed. Further, when the thickness of the homogeneous layer composed of the second polymer derived from the three kinds of monomers (thickness corresponding to T2 in FIG. 1) was measured based on the TEM image in FIG. 2 (b), it was 0.25 μm. there were. Furthermore, when the thickness of the homogeneous layer made of the first polymer which is a crosslinked (meth) acrylic resin (thickness corresponding to T1 in FIG. 1) was measured based on the TEM image in FIG. 2 (b), it was 0.05 μm. Met. For this reason, the thickness of the surface layer (the outer layer of the dispersion layer) of the resin particles obtained in Production Example 1 (that is, the sum of the thickness corresponding to T1 and the thickness corresponding to T2 in FIG. 1) is 0.3 μm. Become.

  Moreover, from the SEM image shown to Fig.2 (a) and the TEM image shown to FIG.2 (b), it was recognized that the surface of the resin particle obtained by manufacture example 1 has a convex part. And the maximum value of the thickness of a convex part (thickness corresponded to T4 of FIG. 1) was 0.5 micrometer when measured based on the TEM image of FIG.2 (b).

[Production Example 2: Production of resin particles]
[First step]
An autoclave having an internal volume of 5 L was charged with 2400 g of water and 164 g of magnesium pyrophosphate as a suspension stabilizer to obtain a dispersed phase. To this dispersed phase, 0.84 g of sodium lauryl sulfate as a surfactant and 0.24 g of sodium nitrite as a polymerization inhibitor were further added.

  Subsequently, 732 g of isobutyl methacrylate, 12 g of allyl methacrylate, 12 g of ethylene glycol dimethacrylate, 12 g of benzoyl peroxide as a polymerization initiator and 15 g of octyl mercaptan as a mercaptan chain transfer agent were mixed in the dispersed phase.

  The obtained mixture was stirred for 10 minutes at a rotational speed of 7500 rpm using the high-speed stirrer to obtain an emulsion.

  The obtained emulsion was reacted at 70 ° C. for 3 hours to obtain an emulsion of a first reaction polymer (crosslinked (meth) acrylic resin particles serving as seed particles) having a volume average particle size of 7.4 μm.

[Second step]
To a stainless steel beaker with an internal volume of 2 L, 432 g of water and 0.05 g of sodium lauryl sulfate as a surfactant are added, and 194.4 g of methyl methacrylate as a monofunctional alkyl (meth) acrylate monomer [A], polyfunctional vinyl 217 g of ethylene glycol dimethacrylate as monomer [B] (1.12 parts by weight with respect to 1 part by weight of methyl methacrylate), poly (ethylene glycol-propylene glycol) as (meth) acrylate monomer [C] having surface-active ability ) Monomethacrylate (manufactured by NOF Corporation, product name: BLEMMER 50 (registered trademark) PEP-300, a mixture comprising a plurality of types of compounds represented by the above formula, wherein R is CH ₃ and m is an average About 3.5, and n is about 2.5 on average) Added azobisisobutyronitrile 4.8g as and a polymerization initiator (0.11 parts by weight to 1 parts by weight of methyl methacrylate), mixing these.

  The obtained mixture was stirred for 10 minutes at a rotational speed of 7500 rpm using the above high-speed stirrer to obtain an emulsion. In addition, the sum total of the usage-amount of the monomer (namely, methyl methacrylate, ethylene glycol dimethacrylate, and poly (ethylene glycol-propylene glycol) monomethacrylate) used at this 2nd process is 433.1g, and this quantity Is the total (756 g) of the amount used of the monomers (ie, isobutyl methacrylate, allyl methacrylate, and ethylene glycol dimethacrylate) used in the production of the crosslinked (meth) acrylic resin particles (seed particles) in the first step. This corresponds to 0.57 times the weight.

[Third step]
The emulsion of the first reaction polymer (cross-linked (meth) acrylic resin particles as seed particles) obtained in the first step in the autoclave is cooled to 60 ° C., and the first reaction polymer (cross-linked (meth)). The emulsion obtained in the second step was continuously dropped into the emulsion of (acrylic resin particles) over 10 minutes. After completion of the dropping, a polymerization reaction was performed at 60 ° C. for 4 hours. Thereafter, 0.3 g of sulfamic acid and 6.3 g of linear alkylbenzene sulfonic acid soda were added, the temperature was raised to 100 ° C., and the reaction was continued at this temperature for 1 hour. Next, after cooling to 30 ° C. and adding hydrochloric acid to decompose magnesium pyrophosphate, washing and dehydration are carried out, followed by drying at 60 ° C. in a vacuum dryer to obtain resin particles having a volume average particle size of 8.6 μm. Obtained.

  The obtained resin particles were imaged with a scanning electron microscope (SEM). Moreover, after embedding the obtained resin particle in an epoxy resin, it cut out to the thin film slice, and after dyeing | staining with ruthenium tetroxide, the cross section was imaged with the transmission electron microscope (TEM). From these SEM images and TEM images, it was confirmed that the resin particles obtained in Production Example 2 had the same internal structure as in Production Example 1. Further, the major axis of the phase of the first polymer which is the crosslinked (meth) acrylic resin in the dispersion layer of the resin particles obtained in Production Example 2 (derived from the crosslinked (meth) acrylic resin particles produced in the first step). The maximum value of (the length corresponding to T4 in FIG. 1) was 100 nm when measured based on the TEM image. Moreover, it consists of a second polymer derived from three types of monomers (monofunctional alkyl (meth) acrylate monomer [A], polyfunctional vinyl monomer [B], and (meth) acrylate monomer [C] having surface activity). When the thickness of the homogeneous layer (thickness corresponding to T2 in FIG. 1) was measured based on the TEM image, it was 0.30 μm. Furthermore, the thickness of the homogeneous layer made of the first polymer that is a crosslinked (meth) acrylic resin (thickness corresponding to T1 in FIG. 1) was measured based on the TEM image, and found to be 0.10 μm. For this reason, the thickness of the surface layer (the outer layer of the dispersion layer) of the resin particles obtained in Production Example 2 (that is, the total thickness corresponding to T1 and T2 in FIG. 1) is 0.4 μm. Become.

  In addition, the resin particles obtained in Production Example 2 were found to have convex portions on the surface, similar to the resin particles obtained in Production Example 1, and the thickness of the convex portions (corresponding to T4 in FIG. 1). The maximum value of the thickness to be measured was 0.15 μm when measured based on the TEM image.

[Comparative Production Example 1: Production of resin particles]
An autoclave having an internal volume of 5 L was charged with 2400 g of water and 164 g of magnesium pyrophosphate as a suspension stabilizer to obtain a dispersed phase. To this dispersed phase, 0.84 g of sodium lauryl sulfate as a surfactant and 0.24 g of sodium nitrite as a polymerization inhibitor were further added.

  Next, 732 g of isobutyl methacrylate, 420 g of methyl methacrylate, 12 g of allyl methacrylate, 15 g of ethylene glycol dimethacrylate, 12 g of benzoyl peroxide as a polymerization initiator and 4.8 g of azobisisobutyronitrile were mixed in the dispersed phase.

  The obtained mixture was stirred for 10 minutes at a rotational speed of 7100 rpm using the above high-speed stirring to obtain an emulsion.

  The obtained emulsion was held at 60 ° C. for 4 hours for polymerization reaction. Thereafter, 0.3 g of sulfamic acid and 6.3 g of linear alkylbenzene sulfonic acid soda were added, the temperature was raised to 100 ° C., and the reaction was continued at this temperature for 1 hour. Next, after cooling to 30 ° C. and adding hydrochloric acid to decompose the magnesium pyrophosphate, washing and dehydration are performed, and drying is performed at 60 ° C. in a vacuum dryer to obtain resin particles having a volume average particle size of 8.3 μm. Obtained.

  The obtained resin particles were imaged with a scanning electron microscope (SEM) and a transmission electron microscope (TEM) in the same manner as the resin particles obtained in Production Example 1, and the SEM shown in FIG. An image and a TEM image shown in FIG. 3B were obtained.

[Comparative Production Example 2: Production of resin particles]
[First step]
An autoclave having an internal volume of 5 L was charged with 2400 g of water and 164 g of magnesium pyrophosphate as a suspension stabilizer to obtain a dispersed phase. To this dispersed phase, 0.84 g of sodium lauryl sulfate as a surfactant and 0.24 g of sodium nitrite as a polymerization inhibitor were further added.

  Next, 732 g of isobutyl methacrylate, 12 g of allyl methacrylate, 12 g of ethylene glycol dimethacrylate, 12 g of benzoyl peroxide as a polymerization initiator and 15 g of octyl mercaptan as a chain transfer agent were mixed in the dispersed phase.

  The obtained mixture was stirred for 10 minutes at a rotational speed of 7500 rpm using the above high-speed stirrer to obtain an emulsion.

  The obtained emulsion was reacted at 70 ° C. for 3 hours to obtain an emulsion of the first reaction polymer (seed particles) having a volume average particle size of 7.4 μm.

[Second step]
To a stainless steel beaker having an internal volume of 2 L, 432 g of water and 0.05 g of sodium lauryl sulfate as a surfactant are added, and 420 g of methyl methacrylate as a monofunctional alkyl (meth) acrylate monomer [A], a polyfunctional vinyl monomer [ B] 13 g of ethylene glycol dimethacrylate (0.03 parts by weight with respect to 1 part by weight of methyl methacrylate) and 4.8 g of azobisisobutyronitrile as a polymerization initiator were mixed.

  The obtained mixture was stirred for 10 minutes at a rotational speed of 7500 rpm using the above high-speed stirrer to obtain an emulsion. The total amount of monomers used in the second step (that is, methyl methacrylate and ethylene glycol dimethacrylate) is 433 g, and this amount is the first reactive polymer (seed) in the first step. This corresponds to 0.57 times the weight of the total amount used (756 g) of the monomers (ie, isobutyl methacrylate, allyl methacrylate, and ethylene glycol dimethacrylate) used in the production of the particles.

[Third step]
The emulsion of the first reaction polymer obtained in the first step in the autoclave is cooled to 60 ° C., and the emulsion obtained in the second step is continuously added to the emulsion of the first reaction polymer for 10 minutes. It was dripped. After completion of the dropping, a polymerization reaction was performed at 60 ° C. for 4 hours. Thereafter, 0.3 g of sulfamic acid and 6.3 g of linear alkylbenzene sulfonic acid soda were added, the temperature was raised to 100 ° C., and the reaction was continued at this temperature for 1 hour. Next, after cooling to 30 ° C. and adding hydrochloric acid to decompose magnesium pyrophosphate, washing and dehydration are carried out, followed by drying at 60 ° C. in a vacuum dryer to obtain resin particles having a volume average particle size of 8.6 μm. Obtained.

[Comparative Production Example 3: Production of resin particles]
[First step]
An autoclave having an internal volume of 5 L was charged with 2400 g of water and 164 g of magnesium pyrophosphate as a suspension stabilizer to obtain a dispersed phase. To this dispersed phase, 0.84 g of sodium lauryl sulfate as a surfactant and 0.24 g of sodium nitrite as a polymerization inhibitor were further added.

  Next, 732 g of isobutyl methacrylate, 12 g of allyl methacrylate, 12 g of ethylene glycol dimethacrylate, and 12 g of benzoyl peroxide as a polymerization initiator were mixed in the dispersed phase.

  The obtained mixture was stirred for 10 minutes at a rotational speed of 7500 rpm using the above high-speed stirrer to obtain an emulsion.

  The obtained emulsion was reacted at 70 ° C. for 3.5 hours to obtain an emulsion of a first reaction polymer (seed particles) having a volume average particle diameter of 7.7 μm.

[Second step]
To a stainless steel beaker having an internal volume of 2 L, 432 g of water and 0.05 g of sodium lauryl sulfate as a surfactant are added, and 420 g of methyl methacrylate as a monofunctional alkyl (meth) acrylate monomer [A], a polyfunctional vinyl monomer [ B] 10 g of ethylene glycol dimethacrylate (0.02 parts by weight with respect to 1 part by weight of methyl methacrylate) and 4.8 g of azobisisobutyronitrile as a polymerization initiator were mixed.

  The obtained mixture was stirred for 10 minutes at a rotational speed of 7500 rpm using the above high-speed stirrer to obtain an emulsion. The total amount of monomers used in the second step (that is, methyl methacrylate and ethylene glycol dimethacrylate) is 430 g, and this amount is the first reactive polymer (seed) in the first step. This corresponds to 0.57 times the weight of the total amount used (756 g) of the monomers (ie, isobutyl methacrylate, allyl methacrylate, and ethylene glycol dimethacrylate) used in the production of the particles.

[Third step]
The emulsion of the first reaction polymer obtained in the first step in the autoclave is cooled to 60 ° C., and the emulsion obtained in the second step is continuously added to the emulsion of the first reaction polymer for 10 minutes. It was dripped. After completion of the dropping, a polymerization reaction was performed at 60 ° C. for 4 hours. Thereafter, 0.3 g of sulfamic acid and 6.3 g of linear alkylbenzene sulfonic acid soda were added, the temperature was raised to 100 ° C., and the reaction was continued at this temperature for 1 hour. Next, after cooling to 30 ° C. and adding hydrochloric acid to decompose magnesium pyrophosphate, washing and dehydration are performed, and drying is performed at 60 ° C. in a vacuum dryer, and resin particles having a volume average particle size of 8.9 μm are obtained. Obtained.

  In addition, the obtained resin particles were imaged with a scanning electron microscope (SEM) and a transmission electron microscope (TEM) in the same manner as the resin particles obtained in Production Example 1 above, and FIG. The SEM image shown and the TEM image shown in FIG. 4B were obtained.

[Example 1: Production of light diffusion film]
100 parts by weight of the resin particles obtained in Production Example 1 and 140 parts by weight of an acrylic binder (manufactured by Mitsubishi Rayon Co., Ltd., product name: Dianal (registered trademark) LR-102) were mixed. 260 parts by weight of a mixed solvent of toluene and methyl ethyl ketone having a weight ratio of 1: 1 was added to and mixed with the obtained mixture to obtain 2.5 g of a dispersion.

  The obtained dispersion was stirred for 3 minutes using a centrifugal stirrer (manufactured by Sinky Corporation, model: AR-100), and then allowed to stand for 3 hours.

  Next, 30 parts by weight of a curing agent (manufactured by Asahi Kasei Chemicals Corporation, product name: Duranate (registered trademark) TKA-100) is added to the dispersion after standing, and the mixture is again stirred for 3 minutes using the centrifugal stirrer. A dispersion (resin composition for the surface layer) was obtained as a paint.

  Next, the dispersion after stirring was applied onto a PET film using a 75 μm coater and dried for 1 hour in a drier kept at 70 ° C., and a light diffusion film provided with a light diffusion layer (surface layer) Got.

  The haze of the obtained light diffusion film was measured.

[Example 2: Production of light diffusion film]
A light diffusion film provided with a light diffusion layer was obtained in the same manner as in Example 1 except that the resin particles obtained in Production Example 2 were used instead of the resin particles obtained in Production Example 1, and the haze was measured. did.

[Comparative Example 1: Production of light diffusion film]
A light diffusing film provided with a light diffusing layer was obtained in the same manner as in Example 1 except that the resin particles obtained in Comparative Production Example 1 were used instead of the resin particles obtained in Production Example 1, and the haze was determined. It was measured.

[Comparative Example 2: Production of light diffusion film]
A light diffusing film provided with a light diffusion layer was obtained in the same manner as in Example 1 except that the resin particles obtained in Comparative Production Example 2 were used instead of the resin particles obtained in Production Example 1, and the haze was determined. It was measured.

[Comparative Example 3: Production of light diffusion film]
A light diffusing film provided with a light diffusion layer was obtained in the same manner as in Example 1 except that the resin particles obtained in Comparative Production Example 3 were used instead of the resin particles obtained in Production Example 1, and the haze was determined. It was measured.

  The results obtained in Production Examples 1 and 2 and Comparative Production Examples 1 to 3 and Examples 1 to 2 and Comparative Examples 1 to 3 corresponding thereto are shown in Tables 1 and 2 together with the materials and conditions used for them.

  Moreover, (a) Scanning electron microscope (SEM) photograph) and (b) Transmission electron microscope (TEM) photograph of the resin particles of Production Example 1 and Comparative Production Example 1 are shown in FIGS. Furthermore, the transmission electron microscope (TEM) photograph of the resin particle of the comparative manufacture example 3 is shown in FIG.

  From the results in Table 1, it can be seen that the light diffusion films (Production Examples 1 and 2 and Examples 1 and 2) provided with the resin particles of the present invention and the surface layer containing the resin particles are excellent in light diffusion performance. Moreover, according to FIG. 2, the surface layer of the resin particles of the present invention obtained in Production Examples 1 and 2 is a crosslinked (meth) acrylic resin (derived from crosslinked (meth) acrylic resin particles (seed particles). And a homogeneous layer composed of a first polymer and a homogeneous layer composed of a second polymer derived from three types of monomers, and the interior (center) of the resin particles of the present invention obtained in Production Examples 1 and 2 Part) includes a first polymer that is a crosslinked (meth) acrylic resin (derived from crosslinked (meth) acrylic resin particles (seed particles)) and a second polymer derived from three types of monomers. It can be seen that a special internal structure (microphase separation structure) is formed. On the other hand, such a state of the resin particles cannot be confirmed with the conventional resin particles of FIGS.

[Example 3: Production example of light diffusing member]
(Manufacture of compounds)
Aromatic polycarbonate resin obtained by reaction of 2,2-bis (4-hydroxyphenyl) propane and a carbonate precursor as a base resin (product name “Taflon (registered trademark) A2500” manufactured by Idemitsu Kosan Co., Ltd.) ) 100 parts by weight and 5 parts by weight of the resin particles obtained in Production Example 1 as a light diffusing agent were mixed with a Henschel mixer for 15 minutes. The obtained mixture was extruded under the conditions of a temperature of 250 to 280 ° C. and a discharge rate of 10 to 25 kg / hr using a single screw extruder (made by Hoshi Plastic Co., Ltd., product name “R50”), and the extruded mixture was cooled with water. Thus, a compound as a resin composition was obtained. The compound was cut with a pelletizer to obtain a pellet-like light diffusing resin composition.

(Manufacture of light diffusion members)
The obtained pellet-like light diffusing resin composition was pre-dried at 120 ° C. for 5 hours to sufficiently remove moisture. Thereafter, by using an injection molding machine (product name “K-80” manufactured by Kawaguchi Tekko Co., Ltd.), the light diffusing resin composition is injection molded under the condition of a cylinder temperature of 255 to 280 ° C. A light diffusion plate having a thickness of 2 mm, a width of 50 mm, and a length of 100 mm was manufactured.

[Example 4: Preparation of external preparation]
After mixing 10 parts by weight of resin particles obtained in Production Example 1, 40 parts by weight of talc, 23 parts by weight of mica, 1 part by weight of red iron oxide and 1 part by weight of yellow iron oxide, 5 parts by weight of petrolatum, myristin 2 parts by weight of octyldodecyl acid, appropriate amounts of preservatives and perfume were supplied to a mixer and mixed uniformly. The mixture was pulverized and passed through a sieve, and then compression molded to obtain a powder foundation.

[Example 5: Production example of external preparation]
3 parts by weight of stearic acid, 2 parts by weight of cetyl alcohol, 5 parts by weight of petroleum jelly, 5 parts by weight of liquid paraffin, and 2 parts by weight of monooleate are dissolved by heating, and 10 parts by weight of the resin particles obtained in Production Example 1 are dissolved therein. Are added and mixed, and kept at 70 ° C. (oil phase). Further, 3 g of polyethylene glycol and 1 part by weight of triethanolamine are added to 65 parts by weight of purified water, dissolved by heating and kept at 70 ° C. (water phase). The oil phase was added to the water phase and pre-emulsified. Thereafter, the mixture was uniformly emulsified with a homomixer, and cooled to 30 ° C. while stirring after emulsification to obtain an emulsion.

DESCRIPTION OF SYMBOLS 1 Dispersion layer 11 Phase which consists of 1st polymer 12 Phase which consists of 2nd polymer 2 Homogeneous layer 3 Homogeneous layer

Claims (12)

Resin particles having a multiphase structure,
A first polymer that is a crosslinked (meth) acrylic resin;
A polyfunctional vinyl monomer having two or more polymerizable carbon-carbon double bonds, represented by the following formula:
(Wherein R1 is H or CH ₃ , m is 0 to 50, and n is 0 to 50, provided that m + n> 1). And a second polymer derived from three monomers of a monofunctional alkyl (meth) acrylate monomer (excluding the (meth) acrylate monomer having the surface activity ability of the above formula),
The first polymer and the second polymer are phase-separated, and a dispersed layer in which a microphase-separated structure in which the phase of the first polymer is dispersed in the form of particles having a major axis of 1 to 200 nm is formed in the center. Have
Resin particles comprising at least one homogeneous layer made of the first polymer or the second polymer outside the dispersion layer. The resin particle according to claim 1,
Resin particles having convex portions on the surface of the resin particles. The resin particle according to claim 1 or 2,
Having two of the homogeneous layers outside the dispersed layer;
One of the homogeneous layers on the dispersion layer side is made of the second polymer, and the other homogeneous layer is made of the first polymer. In the presence of a polymerization initiator, in a water-based emulsion in which crosslinked (meth) acrylic resin particles as seed particles are dispersed under a temperature condition equal to or higher than (10-hour half-life temperature T-10 ° C. of the polymerization initiator) A polyfunctional vinyl monomer having two or more polymerizable carbon-carbon double bonds, represented by the following formula:
(Wherein R1 is H or CH ₃ , m is 0 to 50, and n is 0 to 50, provided that m + n> 1) and a (meth) acrylate monomer having a surface active ability represented by Three types of monomers of monofunctional alkyl (meth) acrylate monomer (excluding the (meth) acrylate monomer having surface active ability of the above formula) are added, and the three types of the above-mentioned crosslinked (meth) acrylic resin particles are added A method for producing resin particles, wherein the resin particles are obtained by polymerization while absorbing monomers. It is a manufacturing method of the resin particles according to claim 4,
A method for producing resin particles, wherein a weight ratio of the crosslinked (meth) acrylic resin particles to the three kinds of monomers is 1: 0.4 to 1.0. It is a manufacturing method of the resin particle according to claim 4 or 5,
The weight ratio of the monofunctional alkyl (meth) acrylate monomer, the polyfunctional vinyl monomer, and the (meth) acrylate monomer having surface activity is 1: 0.03 to 1.5: 0.001 to 0.3. A method for producing resin particles, wherein: A method for producing resin particles according to any one of claims 4 to 6,
The method for producing resin particles, wherein the three kinds of monomers are added to the aqueous emulsion at an addition rate in the range of 3 to 50 g / min with respect to 100 g of the crosslinked (meth) acrylic resin particles.   The coating material containing the resin particle as described in any one of Claims 1-3.   An external preparation comprising the resin particles according to any one of claims 1 to 3.   A resin composition comprising the resin particles according to claim 1.   The light-diffusion member characterized by including the resin particle as described in any one of Claims 1-3.   A light diffusion comprising a surface layer formed from a resin composition for a surface layer comprising 10 to 500 parts by weight of the resin particles according to any one of claims 1 to 3 and 100 parts by weight of a binder resin. the film.