JP5666487B2 - Oval shaped resin particles, production method thereof, and use thereof - Google Patents

Description

  The present invention relates to a light diffusing agent (light diffusing body) such as a light diffusing sheet (light diffusing film), a light diffusing plate, a lighting cover (lighting cover for LED lighting, etc.); Light diffusion agent constituting light diffusive coating agent such as coating agent for paper coating agent (coating agent for paper), coating agent for light diffusing member, etc .; antiglare agent Light diffusing agent that constitutes a film; irregularly shaped resin particles that can be used as a raw material for external preparations such as cosmetics (for example, additives such as slipperiness improvers), its production method, and its use (external preparations, paints, and Light diffusing member).

  Conventionally, irregularly shaped resin particles produced by seed polymerization are known. For example, in Comparative Example 5 of Patent Document 1 and Comparative Example 1 of Patent Document 2, dharma-like polymer particles are described.

  Patent Document 3 describes polymer particles having a bowl-like shape. Patent Document 3 discloses that the polymer particles having a bowl-like shape are effective for adding to a paint or cosmetics and imparting them viscosity characteristics, light scattering characteristics, and other unique surface characteristics. Is described.

  Patent Document 4 describes polymer particles having a concave cross-sectional shape, a mushroom-like shape, a hemispherical shape, or a double-sided lens-like shape having one cutout portion communicating in the diametrical direction.

JP-A-8-120005 JP 2011-63758 A JP 2008-163171 A International Publication No. 2010/113812

  Conventionally known irregularly shaped resin particles are limited to the shape as described above, and do not necessarily have desired characteristics (light diffusibility, adhesion, oil absorption, etc.), so there is room for further improvement. If it is possible to provide irregular shaped resin particles having a novel shape, it is considered possible to improve the properties of the irregular shaped resin particles such as light diffusibility, adhesion, and oil absorption.

  Patent Documents 1 to 4 do not disclose odd-shaped resin particles in which the resin core is unevenly distributed in an ellipsoidal shape. If it is possible to provide deformed resin particles in which such resin cores are unevenly distributed in an elliptical shape, it is considered that characteristics such as light diffusibility of the deformed resin particles can be improved.

  An object of the present invention is to provide a novel shaped irregular shaped resin particle capable of improving properties such as light diffusibility, adhesion and oil absorption, a method for producing the same, an external preparation excellent in moisture retention, and a coating excellent in scratch resistance. An object of the present invention is to provide a paint capable of forming a film and a light diffusing member excellent in light diffusibility.

  The irregularly shaped resin particles of the present invention are irregularly shaped resin particles comprising a resin layer that forms the surface layer of irregularly shaped resin particles and a resin core made of a resin component different from the resin layer and formed inside the resin layer. And the resin core has an ellipsoidal shape and is adjacent to the depression, and the ratio B / of the minor diameter B of the deformed resin particle to the major diameter A of the deformed resin particle A is characterized by being 0.7 or more.

  Since the irregular shaped resin particles having the above-described configuration have a depression, the specific surface area is large, and advantageous effects can be obtained in various applications.

  For example, when a deformed resin particle is mixed with a binder (adhesive) to produce a coating agent or paint (such as for optical film use), if the deformed resin particle has a large specific surface area, the contact area with the binder increases. Therefore, the adhesiveness with respect to a binder improves. Therefore, when the coating agent or paint is applied to the surface to be coated, it is difficult to drop off from the coating film of the coating agent or paint, and a coating or paint film having excellent scratch resistance can be formed.

  Further, when the irregular shaped resin particles are added to an external preparation such as cosmetics, if the specific surface area of the irregular shaped resin particles is large, the amount of oil absorption increases, so that the oil absorbency of the external preparation such as cosmetics can be improved. Moreover, the adaptability to an external preparation can be improved because the oil-absorbing property of the irregular shaped resin particles is high.

  In addition, because the specific surface area of the irregular shaped resin particles is large, light is refracted or reflected when the irregular shaped resin particles are used as a light diffusing agent constituting a light diffusing member such as a light diffusing sheet, a light diffusing plate, or a lighting cover. Since the interface (with other substances) of the irregular shaped resin particles becomes wide, light diffusibility is improved.

  Further, the odd-shaped resin particles having the above-described configuration have a ratio B / A of the short diameter B of the odd-shaped resin particles to the long diameter A of the odd-shaped resin particles of 0.7 or more, and the surface shape is nearly spherical. Is small and has good slipperiness, the tactile sensation is improved when the irregularly shaped resin particles are added to an external preparation such as cosmetics.

  Furthermore, the odd-shaped resin particles having the above-described configuration are made of a resin component different from that of the resin layer and have a resin core formed inside the resin layer, so that light is easily refracted at the interface between the resin layer and the resin core. And since the resin core is largely unevenly distributed because it is adjacent to the recess, and has an ellipsoidal shape, the thickness of the resin layer surrounding the resin core increases with increasing distance from the recess. As a result, the way of refraction (such as the refraction angle) at the interface between the resin layer and the resin core differs depending on the direction of incidence of light on the irregular shaped resin particles. As a result, the irregular shaped resin particle (s) diffuse light unevenly even when light from the same direction is incident. Therefore, the irregular shaped resin particles having the above-described structure easily refract light, and when the irregular shaped resin particles are used as a light diffusing agent constituting a light diffusing member such as a light diffusing sheet, a light diffusing plate, and a lighting cover, Will improve.

  As described above, according to the modified resin particles of the present invention, characteristics such as light diffusibility, adhesion, and oil absorption can be improved.

  In this specification, “the resin core is adjacent to the depression” means that the distance between the deformed resin particle surface and the resin core in the depression is the minor axis B of the irregular resin particle and the minor axis of the resin core. Means less than half of the difference. In this specification, “ellipsoidal shape” means a spherical shape or an elliptical shape that is not a sphere. Further, in this specification, “ellipsoidal shape” includes a shape in which a part of an ellipsoid is missing.

The method for producing irregular shaped resin particles of the present invention is a method for producing irregular shaped resin particles having a single depression,
A first step of producing resin particles by polymerizing a fluorine-containing (meth) acrylic acid ester monomer containing 0.1 to 5% by mass of a polyfunctional monomer;
A second step of polymerizing the resin particles obtained in the first step after absorbing a (meth) acrylic acid ester-based monomer containing 1 to 50% by mass of a polyfunctional monomer; It is characterized by including.

  According to the above method, since resin particles are obtained by polymerizing a fluorine-containing (meth) acrylate monomer containing 0.1% by mass or more of a polyfunctional monomer, the resulting resin particles are crosslinked. It is a polymer that exhibits sufficient structural properties. As a result, when the (meth) acrylate monomer is absorbed by the resin particles, the (meth) acrylate monomer is easily phase-separated from the resin particles, and the shape of the resin particles Is easily maintained. Further, according to the above method, since resin particles are obtained by polymerizing a fluorine-containing (meth) acrylic acid ester monomer containing a polyfunctional monomer at 5% by mass or less, the obtained resin particles are: It is a polymer having a crosslinked structure with a relatively low degree of crosslinking. Thereby, the (meth) acrylic acid ester monomer is sufficiently absorbed by the resin particles.

  Moreover, according to the said method, the usage-amount of the polyfunctional monomer in a said 2nd process exists in the range of 1-50 mass% with respect to the whole quantity of a (meth) acrylic-ester type monomer. Therefore, it is assumed that the phase separation from the resin particles is easy when the (meth) acrylic acid ester monomer is polymerized.

  As described above, according to the above method, when the (meth) acrylic acid ester monomer is absorbed by the resin particles, the (meth) acrylic acid ester monomer is sufficiently absorbed by the resin particles, The (meth) acrylic acid ester monomer and the polymer thereof are easily phase separated from the resin particles, and the shape of the resin particles is easily maintained. Due to these synergistic effects, the phase separation causes a single depression, the resin core is adjacent to the depression, and is a nearly spherical deformed resin particle, in particular the ratio B / A of the short diameter B to the long diameter A The irregular shaped resin particles of the present invention having a ratio of 0.7 or more can be produced.

  Furthermore, in the above method, the polyfunctional monomer is added to resin particles (that is, crosslinked seed particles) obtained by polymerizing a fluorine-containing (meth) acrylate monomer containing a polyfunctional monomer. Since the polymerization is carried out by absorbing the (meth) acrylic acid ester monomer contained therein, the seed is absorbed by the non-crosslinked seed particles as described in Examples 1 to 17 of Patent Document 4. Compared with the method of performing polymerization, it is possible to obtain deformed resin particles having a high degree of cross-linking of the part derived from the seed particles. Therefore, when the deformed resin particles obtained by the above method are put in a solvent, the portion derived from the seed particles is reduced from bleeding out and eluted. As a result of reduced elution, when mixed with a solvent to make a paint or coating agent, it is possible to prevent the coating from becoming difficult due to the increase in viscosity due to elution or the coating from becoming uneven due to elution. it can. In addition, the deformed resin particles obtained by the above method can avoid deterioration of properties due to elution of components when mixed with a solvent, even when used for other applications such as molded products and external preparations. Has solvent resistance. Therefore, the deformed resin particles obtained by the above method have advantageous properties in a wide range of applications.

  Here, in this specification, “(meth) acryl” means acryl or methacryl, and “(meth) acrylate” means acrylate or methacrylate.

  In the present specification, the “(meth) acrylic acid ester monomer” means a monomer having (meth) acrylic acid ester as a main component (including 50% by mass or more).

  In addition, in the manufacturing method of the particle | grains described in patent documents 1-4, it is impossible to obtain the irregular-shaped resin particle which has the characteristic shape which concerns on this invention.

  First, in the method for producing particles according to claim 1 of Patent Document 1, as described in paragraph [0013] of Patent Document 1, a monomer and a crosslinking agent are uniformly supplied to the seed polymerization active sites. Therefore, true spherical polymer particles can be obtained. Similarly, in the method for producing particles according to claim 5 of Patent Document 2, true spherical polymer particles are obtained as described in paragraph [0009] of Patent Document 2.

  Further, the method for producing particles described in Comparative Example 5 of Patent Document 1 and the method for producing particles described in Comparative Example 1 of Patent Document 2 are obtained by copolymerizing methyl methacrylate and a crosslinkable monomer. Since the monomer is absorbed into the resin particles and seed polymerization is performed, the monomer is added to the resin particles obtained by polymerizing a fluorine-containing (meth) acrylate monomer containing a polyfunctional monomer. Compared with the production method of the present invention in which seed polymerization is carried out by absorbing water, phase separation between the seed particles and the monomer is less likely to occur, so that only Dharma-shaped deformed resin particles can be obtained.

  Further, the method for producing particles described in the claims of Patent Document 3 performs seed polymerization by absorbing a monomer into resin particles obtained by copolymerizing methyl methacrylate and the like and a crosslinkable monomer. Compared with the production method of the present invention in which a monomer is absorbed into resin particles obtained by polymerizing a fluorine-containing (meth) acrylic acid ester-based monomer containing a polyfunctional monomer and seed polymerization is performed. Thus, since phase separation between the seed particles and the monomer is difficult to occur, only cocoon-shaped deformed resin particles can be obtained.

  In addition, in the method for producing particles described in Examples 1 to 17 of Patent Document 4, the monomer is absorbed into the non-crosslinked seed particles obtained by polymerization of methyl methacrylate and polymerization of branched alkyl methacrylate, and seed polymerization is performed. Therefore, the resin is obtained by polymerizing a fluorine-containing (meth) acrylic acid ester-based monomer containing a polyfunctional monomer, that is, the monomer is absorbed and seed polymerization is performed. Compared with the production method of the present invention to be performed, the spherical resin portion derived from the spherical shape of the seed particles is less likely to be formed inside, and phase separation occurs in a form different from the production method of the present invention, and therefore communicates in the diameter direction. Only deformed resin particles having a cross-sectional concave shape, a mushroom shape, a hemispherical shape, or a double-sided lens shape having one cutout portion can be obtained.

  The external preparation of the present invention is characterized by containing the deformed resin particles of the present invention.

  According to the said structure, since the resin particle is excellent in oil absorption, the external preparation excellent in moisture retention can be provided.

  The paint of the present invention is characterized by containing the irregular shaped resin particles of the present invention.

  According to the said structure, since the resin particle is excellent in adhesiveness and cannot fall easily from a coating film, the coating material which can form the coating film excellent in scratch resistance can be provided.

  The light diffusing member of the present invention is characterized by including the irregular shaped resin particles of the present invention.

  According to the said structure, since the resin particle is excellent in light diffusivity, the light-diffusion member excellent in light diffusibility can be provided.

  As described above, according to the present invention, it is possible to provide a deformed resin particle having a novel shape capable of improving characteristics such as light diffusibility, adhesion, and oil absorption, and a method for producing the same.

  Moreover, according to this invention, the external preparation excellent in moisture retention, the coating material which can form the coating film excellent in scratch resistance, and the light-diffusion member excellent in light diffusibility can be provided.

It is sectional drawing which shows typically the deformed resin particle which concerns on one Example of this invention. It is a SEM image obtained by imaging the surface of the irregular-shaped resin particle obtained in the other Example of this invention with the scanning electron microscope (SEM). It is the TEM image obtained by imaging the cross section of the irregular shaped resin particle obtained in the other Example of this invention with the transmission electron microscope (TEM). It is a SEM image obtained by imaging the surface of the irregular-shaped resin particle obtained in the further another Example of this invention by SEM. It is a SEM image obtained by imaging the surface of the irregular-shaped resin particle obtained by the comparative example by SEM.

  Hereinafter, the present invention will be described in detail.

[Deformed resin particles]
The shape of the irregular shaped resin particles of the present invention will be described in more detail based on FIG.

  For example, as shown in FIG. 1, the deformed resin particle of the present invention is a deformed resin particle including a resin layer 1 forming a surface layer of the deformed resin particle and a resin core 2 formed inside the resin layer 1. The resin core 2 has an ellipsoidal shape and is adjacent to the recess 3. The resin core 2 is made of a resin component different from that of the resin layer 1, and the ratio B / A of the minor diameter B of the irregular shaped resin particles to the major diameter A of the irregular shaped resin particles is 0.7 or more. The shape of the resin core 2 does not have to be a complete ellipsoidal shape, but may be a substantially ellipsoidal shape.

  The ratio B / A of the minor axis B of the irregularly shaped resin particle to the major axis A of the irregularly shaped resin particle is preferably in the range of 0.7 to 0.9 (0.7 or more and 0.9 or less). More preferably, it is within the range of .8 to 0.9. When the ratio B / A is less than 0.7, the shape of the irregularly shaped resin particles is far from the spherical shape and close to a hemispherical shape, so that the performance is deteriorated in terms of slipperiness. When the ratio B / A exceeds 0.9, the depth of the dent 3 becomes shallow, and the specific surface area of the deformed resin particle becomes close to a true spherical resin particle. The effect of improving properties such as diffusibility, adhesion, and oil absorption is reduced.

  It is preferable that the ratio C / A of the diameter C of the recess 3 (diameter in the major axis direction of the irregularly shaped resin particles) C to the major axis A of the irregularly shaped resin particles is in the range of 0.1 to 0.4. When the ratio C / A is less than 0.1, the diameter (width) C of the dent 3 is small, and the specific surface area of the deformed resin particles is close to that of a true spherical resin particle. The effect of improving characteristics such as light diffusibility, adhesion, and oil absorption for a certain case is reduced. In addition, when the ratio C / A exceeds 0.4, the diameter C of the recess 3 is increased, so that the shape of the deformed resin particles is far from a spherical shape and close to a hemispherical shape. Get smaller.

  The ratio D / A of the major axis D of the resin core 2 to the major axis A of the irregularly shaped resin particles is preferably in the range of 0.2 to 0.7. When the ratio D / A is less than 0.2, the diameter of the resin core 2 is small, and refraction at the interface between the resin layer 1 and the resin core 2 is difficult to occur, so that the effect of improving the light diffusibility is small. Become. When the ratio D / A exceeds 0.7, the thickness of the resin layer 1 becomes thin and non-uniform light diffusion hardly occurs, so the effect of improving the light diffusibility becomes small.

  The irregular shaped resin particles of the present invention have a ratio B / A in the range of 0.7 to 0.9, a ratio C / A in the range of 0.1 to 0.4, and a ratio D / A. Is in the range of 0.2 to 0.7, the shape of the deformed resin particles as a whole is farther from the spherical shape, so that it is possible to improve the slip properties such as light diffusibility, adhesion, and oil absorption. .

  The ratio E / D of the minor axis E of the resin core 2 to the major axis D of the resin core 2 is preferably 0.7 or more. When the ratio E / D is less than 0.7, the shape of the resin core 2 is far from the spherical shape, and refraction at the interface between the resin layer 1 and the resin core 2 is less likely to occur, thereby improving the light diffusibility. Becomes smaller.

  The irregular shaped resin particles of the present invention preferably have a particle diameter variation coefficient of 15% or less. Thereby, the uniformity (between particles) of the characteristics of the irregular shaped resin particles is improved. Therefore, when a product such as a light diffusing member, an external preparation, or a paint is produced using the irregular shaped resin particles of the present invention, a product such as a light diffusing member, an external preparation, or a paint having uniform optical characteristics is obtained. It is done.

  The deformed resin particles of the present invention preferably have an average particle diameter in the range of 0.5 to 50 μm. Thereby, it becomes a particle suitable for various uses. When the irregular shaped resin particles of the present invention are used as a component (light diffusing agent) of an antiglare film, the average particle diameter is more preferably in the range of 1.5 to 8 μm. Thereby, the anti-glare film which has favorable anti-glare property is realizable. Moreover, when using the irregular shaped resin particle of this invention as a component (light-diffusion agent) of a light-diffusion member, it is more preferable that an average particle diameter exists in the range of 1-50 micrometers, and an average particle diameter is 3-10 micrometers. More preferably, it is within the range. Thereby, the light-diffusion member which has favorable light diffusibility is realizable. Moreover, when using the irregular shaped resin particle of this invention as a raw material of an external preparation, it is preferable that an average particle diameter exists in the range of 1-50 micrometers. Thereby, a favorable external preparation can be realized. Moreover, when the irregular shaped resin particle of this invention is used as a coating agent for paper, it is preferable that an average particle diameter exists in the range of 0.5-10 micrometers. Thereby, a good paper coating agent can be realized. In addition, when the average particle diameter is in the range of 1 to 10 μm, particularly when the average particle diameter is in the range of 1 to 3 μm, the shape of the deformed resin particles can be easily controlled to a desired shape. Thus, the production of the irregular shaped resin particles becomes easy.

  The resin layer 1 and the resin core 2 are preferably made of a (meth) acrylic ester resin. Thereby, the irregular-shaped resin particle excellent in weather resistance is realizable. The (meth) acrylic acid ester resin means a resin obtained by polymerizing a monomer having (meth) acrylic acid ester as a main component (including 50% by mass or more).

  It is preferable that the resin layer 1 is crosslinked with 1 to 50% by mass of a polyfunctional monomer with respect to the total mass of the resin layer 1. Thereby, the solvent resistance of irregular-shaped resin particle can be improved. In addition, the resin layer 1 crosslinked with 1 to 50% by mass of the polyfunctional monomer with respect to the total mass of the resin layer 1 is 1 to 50% by mass of the polyfunctional monomer and the monofunctional monomer. It is obtained by polymerizing a monomer mixture containing a body.

  The resin core 2 is preferably made of a fluorine-containing (meth) acrylic acid ester resin crosslinked with 0.1 to 5% by mass of a polyfunctional monomer with respect to the total mass of the resin core 2. When the resin core 2 is cross-linked with 0.1 to 5% by mass of a polyfunctional monomer, the portion derived from the seed particles when the solvent is put in a solvent is reduced from bleeding out. . In addition, since the (meth) acrylic acid ester-based resin contains fluorine, it becomes easy to realize a deformed shape peculiar to the present invention, so that the manufacture is facilitated. Furthermore, since the refractive index of the resin core 2 is reduced by the fluorine contained in the (meth) acrylic acid ester resin, refraction at the interface between the resin layer 1 and the resin core 2 is likely to occur, and light diffusibility is achieved. Will improve. The fluorine-containing (meth) acrylic ester resin crosslinked with 0.1 to 5% by mass of a polyfunctional monomer with respect to the total mass of the resin core 2 is 0.1 to 5% by mass. It is obtained by polymerizing a monomer mixture containing a functional monomer and a (monofunctional) fluorine-containing (meth) acrylic acid ester monomer.

[Method for producing irregularly shaped resin particles]
The manufacturing method of the irregular shaped resin particle which concerns on this invention is a manufacturing method of the irregular shaped resin particle which has a single hollow, Comprising: The fluorine-containing (meth) acrylic acid containing 0.1-5 mass% of polyfunctional monomers In the first step of producing resin particles by polymerizing 100 parts by mass of an ester monomer (hereinafter referred to as “fluorine-containing monomer mixture”), the resin particles obtained in the first step are 1 to Second step of polymerizing after absorbing (meth) acrylic acid ester-based monomer (hereinafter referred to as “(meth) acrylic monomer mixture”) containing 50% by mass of polyfunctional monomer That is, a seed polymerization step. By this method, the irregular shaped resin particles of the present invention can be produced with high certainty.

[Seed particle manufacturing process]
The first step is a step of producing resin particles used for absorbing the (meth) acrylic monomer mixture in the seed polymerization step, that is, seed particles. In the first step, 0.1 to 5% by mass of a polyfunctional monomer in the absence of a polymer of (meth) acrylic acid ester or in the presence of a polymer of (meth) acrylic acid ester. The fluorine-containing monomer mixture containing is polymerized to obtain seed particles.

  The fluorine-containing monomer mixture contains at least a fluorine-containing (meth) acrylic acid ester and a polyfunctional monomer. Examples of the fluorine-containing (meth) acrylic acid ester include 2,2,2-trifluoroethyl acrylate (for example, “Biscoat V-3F” manufactured by Osaka Organic Chemical Industry Co., Ltd.), 2,2,2-trifluoroethyl. Methacrylate (for example, “Biscoat V-3F M” manufactured by Osaka Organic Chemical Industries, Ltd.), 2,2,3,3-tetrafluoropropyl acrylate (for example, “Biscoat V-4F” manufactured by Osaka Organic Chemical Industries, Ltd.) ), 1H, 1H, 5H-octafluoropentyl acrylate (for example, “Biscoat V-8F” manufactured by Osaka Organic Chemical Industries, Ltd.), 1H, 1H, 5H-octafluoropentyl methacrylate (for example, Osaka Organic Chemical Industries, Ltd.) "Biscoat V-8FM" manufactured by the same company). These compounds may be used alone or in combination of two or more.

  The fluorine-containing (meth) acrylic acid ester is used within a range of 99.9% by mass or less with respect to the fluorine-containing monomer mixture, but is 75 to 99.9 mass with respect to the fluorine-containing monomer mixture. % Is more preferable, and it is even more preferable that it is used in the range of 90 to 99.9% by mass with respect to the fluorine-containing monomer mixture. When a resin particle is produced by polymerizing a fluorine-containing monomer mixture comprising 75% by mass or more of a fluorine-containing (meth) acrylic acid ester, and the (meth) acrylic monomer mixture is absorbed by the resin particle In addition, the (meth) acrylic monomer mixture is easily phase-separated from the resin particles, and an irregular shape peculiar to the present invention is easily obtained.

  The polyfunctional monomer is a compound having two or more polymerizable alkenyl groups (broadly defined vinyl groups) in one molecule. Examples of the polyfunctional monomer include ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and pentaerythritol tetra. (Meth) acrylate, divinylbenzene and the like can be mentioned. It is preferable that the polyfunctional monomer does not include a divalent linear hydrocarbon group having 4 or more carbon atoms between a polymerizable alkenyl group and another polymerizable alkenyl group. When the polyfunctional monomer contains a divalent linear hydrocarbon group having 4 or more carbon atoms between a polymerizable alkenyl group and another polymerizable alkenyl group, seed particles and (meta ) Phase separation from the acrylic monomer mixture is unlikely to occur, and it is difficult to obtain a deformed shape peculiar to the present invention.

  The polyfunctional monomer is used in the range of 0.1 to 5 parts by mass with respect to 100 parts by mass of the fluorine-containing monomer mixture, but 0 to 100 parts by mass of the fluorine-containing monomer mixture. More preferably, it is used within the range of 1 to 3 parts by mass. By making the polyfunctional monomer 0.1 mass part or more with respect to 100 mass parts of the fluorine-containing monomer mixture, phase separation between the seed particles and the (meth) acrylic monomer mixture is more likely to occur. Thus, it becomes easy to obtain a deformed shape peculiar to the present invention. In addition, when a polyfunctional monomer exceeds 5 mass parts with respect to 100 mass parts of fluorine-containing monomer mixtures, the cross-linking degree of seed particles becomes too high, and the seed particles are (meth) acrylic monomers. It becomes difficult to absorb the mixture, and a phenomenon occurs in which the (meth) acrylic monomer mixture is polymerized without being absorbed by the seed particles. Therefore, in this case, many fine particles are generated, and the coefficient of variation (CV value) of the particle diameter increases, which is not preferable.

  The fluorine-containing monomer mixture may contain a monofunctional monomer other than the fluorine-containing (meth) acrylic acid ester. The monofunctional monomer is a compound having only one polymerizable alkenyl group (broadly-defined vinyl group) in one molecule. As the monofunctional monomer other than the fluorine-containing (meth) acrylic acid ester, a monofunctional (meth) acrylic acid ester other than the fluorine-containing (meth) acrylic acid ester is preferable. Monofunctional (meth) acrylic acid esters other than fluorine-containing (meth) acrylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n- Butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, n-heptyl (meth) acrylate, n-octyl (meth) Examples include acrylate, 2-ethylhexyl (meth) acrylate, n-nonyl (meth) acrylate, n-decyl (meth) acrylate, and cyclohexyl (meth) acrylate. These compounds may be used alone or in combination of two or more. The amount of the monofunctional monomer other than the fluorine-containing (meth) acrylic acid ester is preferably 20 parts by mass or less with respect to 100 parts by mass of the fluorine-containing monomer mixture. More preferably.

  The polymerization of the fluorine-containing monomer mixture is more preferably performed in the presence of a chain transfer agent. Examples of the chain transfer agent include mercaptans such as n-octyl mercaptan and tert-dodecyl mercaptan; α-methylstyrene dimer; terpenes such as γ-terpinene and dipentene; halogenated hydrocarbons such as chloroform and carbon tetrachloride, etc. Can be used. As the chain transfer agent, mercaptans are preferable, and n-octyl mercaptan is particularly preferable. The chain transfer agent is more preferably used within a range of 0.1 to 0.9 parts by mass with respect to 100 parts by mass of the fluorine-containing monomer mixture, and 100 parts by mass of the fluorine-containing monomer mixture. More preferably, it is used within the range of 0.1 to 0.5 parts by mass relative to the mass. When the amount of the chain transfer agent used is 0.9 parts by mass or less with respect to 100 parts by mass of the fluorine-containing monomer mixture, the molecular chain of the resin particles obtained by polymerization does not become too short. The shape is easily maintained. Therefore, phase separation between the seed particles and the (meth) acrylic monomer mixture is more likely to occur, and an irregular shape peculiar to the present invention is easily obtained. On the other hand, when the amount of the chain transfer agent used is 0.1 parts by mass or more with respect to 100 parts by mass of the fluorine-containing monomer mixture, the molecular chain of the resin particles obtained by polymerization does not become too long. ) The acrylic monomer mixture is sufficiently absorbed by the resin particles.

  In the first step, when the fluorine-containing monomer mixture is polymerized to obtain seed particles, a known method such as emulsion polymerization or suspension polymerization can be used. In view of the uniformity of the seed particle size and the simplicity of the production method, emulsion polymerization is preferred. Although the method using emulsion polymerization is described below, it is not limited to this method.

  When obtaining seed particles by emulsion polymerization of the fluorine-containing monomer mixture, first, the fluorine-containing monomer mixture is dispersed in an aqueous medium to prepare an aqueous emulsion.

  Examples of the aqueous medium include water and a mixed medium of water and a water-soluble solvent (for example, a lower alcohol (alcohol having 5 or less carbon atoms)). In the aqueous medium, a surfactant described later in the section of [Seed polymerization step] may or may not be added. The fluorine-containing monomer mixture is added to an aqueous medium, and the fluorine-containing monomer mixture is dispersed in an aqueous medium using a fine emulsifier such as a main stirrer, a homogenizer, a sonicator, or a nanomizer. The dispersion is heated to the polymerization temperature. After purging (replacement) the reaction system with an inert gas such as nitrogen, seed particles are obtained by performing polymerization while sequentially adding a solution of a polymerization initiator dissolved in water to the dispersion.

  Examples of the polymerization initiator include persulfates such as potassium persulfate, ammonium persulfate, and sodium persulfate; benzoyl peroxide, lauroyl peroxide, benzoyl peroxide, orthomethoxybenzoyl peroxide, 3,5,5- Organic peroxides such as trimethylhexanoyl peroxide, tert-butylperoxy-2-ethylhexanoate, di-tert-butyl peroxide; 2,2′-azobisisobutyronitrile, 1,1′- Examples thereof include azo compounds such as azobiscyclohexanecarbonitrile and 2,2′-azobis (2,4-dimethylvaleronitrile). The polymerization initiator is preferably used within a range of 0.1 to 3 parts by mass with respect to 100 parts by mass of the fluorine-containing monomer mixture.

  Next, seed particles are obtained by polymerizing the fluorine-containing monomer mixture in the aqueous emulsion. The polymerization temperature can be appropriately selected according to the type of the fluorine-containing monomer mixture and the type of the polymerization initiator. The polymerization temperature is preferably 25 to 110 ° C, more preferably 50 to 100 ° C. If necessary, after completion of the polymerization, the seed particles may be separated from the aqueous medium by filtration or the like, the aqueous medium may be removed from the seed particles by centrifugation or the like, washed with water and a solvent, and then dried.

  As described above, seed particles composed of a cross-linked fluorine-containing (meth) acrylic ester resin are obtained.

  On the other hand, in the first step, when obtaining the seed particles by polymerizing the fluorine-containing monomer mixture in the presence of the (meth) acrylic acid ester polymer, the (meth) acrylic acid ester polymer is It is preferably used in an amount of 100 parts by mass or less with respect to 100 parts by mass of the fluorine-containing monomer mixture, and more preferably in the range of 1 part by mass to 80 parts by mass. When the polymer of (meth) acrylic acid ester is 100 parts by mass or less with respect to 100 parts by mass of the fluorine-containing monomer mixture, phase separation between the seed particles and the (meth) acrylic monomer mixture is likely to occur. Therefore, it becomes easy to form a deformed shape peculiar to the present invention. On the other hand, when the polymer of (meth) acrylic acid ester is 1 part by mass or more with respect to 100 parts by mass of the fluorine-containing monomer mixture, the fluorine-containing monomer mixture is not absorbed by the seed particles and the aqueous medium It is possible to avoid the generation of abnormal particles by suspension polymerization.

  In this case, after the (meth) acrylic acid ester is polymerized to obtain the (meth) acrylic acid ester polymer particles, the fluorine-containing single monomer containing the fluorine-containing (meth) acrylic acid ester and the polyfunctional monomer. It is preferable to use a seed polymerization method in which a body mixture is absorbed and polymerized by the (meth) acrylic acid ester polymer particles. That is, in the first step, a (meth) acrylic acid ester is polymerized to obtain (meth) acrylic acid ester polymer particles, and the fluorine-containing monomer mixture is converted into the (meth) acrylic acid ester. It is preferable to prepare seed particles in two stages, a second stage in which the polymer particles are absorbed and polymerized. Thereby, it becomes easy to obtain deformed resin particles having a deformed shape peculiar to the present invention in a seed polymerization step described later. In addition, the manufacturing method of the particle | grains of (meth) acrylic acid ester polymer particle | grain is mentioned later.

  In the seed polymerization method, first, the fluorine-containing monomer mixture is dispersed in an aqueous medium to prepare an aqueous emulsion, and (meth) acrylate polymer particles are added as seed particles to the aqueous emulsion. As the aqueous medium, the aforementioned medium can be used. A surfactant described later in the section of [Seed polymerization step] may be added to the aqueous medium. Further, as described above, the polymerization of the fluorine-containing monomer mixture is more preferably performed in the presence of a chain transfer agent.

  You may mix the polymerization initiator mentioned above with the said fluorine-containing monomer mixture as needed. The polymerization initiator may be preliminarily mixed with the fluorine-containing monomer mixture and then dispersed in an aqueous medium, or a mixture obtained by separately dispersing both in an aqueous medium. The particle diameter of the droplets of the fluorine-containing monomer mixture in the obtained aqueous emulsion is smaller than the (meth) acrylic acid ester polymer particles, and the fluorine-containing monomer mixture is (meth) acrylic. The acid ester polymer particles are preferred because they are efficiently absorbed. The polymerization initiator is preferably used within a range of 0.1 to 3 parts by mass with respect to 100 parts by mass of the fluorine-containing monomer mixture.

  The (meth) acrylic acid ester polymer particles may be added directly to the aqueous emulsion, or the (meth) acrylic acid ester polymer particles may be added to the aqueous emulsion in a form dispersed in an aqueous medium. After the (meth) acrylic acid ester polymer particles are added to the aqueous emulsion, the (meth) acrylic acid ester polymer particles are allowed to absorb the fluorine-containing monomer mixture. This absorption can be normally performed by stirring the aqueous emulsion after adding the (meth) acrylic ester polymer particles at room temperature (about 20 ° C.) for 1 to 12 hours. Moreover, you may accelerate | stimulate absorption by heating an aqueous emulsion to about 30-50 degreeC.

  The (meth) acrylic acid ester polymer particles are swollen by absorption of the fluorine-containing monomer mixture. The end of absorption can be determined by confirming the enlargement of the particle diameter by observation with an optical microscope.

  Next, seed particles are obtained by polymerizing the fluorine-containing monomer mixture absorbed in the (meth) acrylic acid ester polymer particles. The polymerization temperature can be appropriately selected according to the type of the fluorine-containing monomer mixture and the type of the polymerization initiator. The polymerization temperature is preferably 25 to 110 ° C, more preferably 50 to 100 ° C. The polymerization reaction is preferably performed by raising the temperature after the fluorine-containing monomer mixture is completely absorbed by the (meth) acrylic acid ester polymer particles. If necessary, after completion of the polymerization, the seed particles may be separated from the aqueous medium by filtration or the like, the aqueous medium may be removed from the seed particles by centrifugation or the like, washed with water and a solvent, and then dried.

  As described above, seed particles composed of a cross-linked fluorine-containing (meth) acrylic acid ester resin are obtained by polymerization in the presence of (meth) acrylic acid ester polymer particles. The size and shape of the seed particles are not particularly limited. As the seed particles, spherical particles having an average particle diameter of 0.1 to 5 μm are usually used.

[Method for producing (meth) acrylic acid ester polymer particles]
Next, the manufacturing method of the (meth) acrylic acid ester polymer particle | grain used as needed in a seed particle manufacturing process is demonstrated.

  In the method for producing (meth) acrylic acid ester polymer particles, (meth) acrylic acid ester is polymerized. As (meth) acrylic acid ester, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert -Butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, n-heptyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-nonyl The various compounds mentioned above as (meth) acrylate, n-decyl (meth) acrylate, cyclohexyl (meth) acrylate, fluorine-containing (meth) acrylic acid ester, etc. may be mentioned. These compounds may be used alone or in combination of two or more. The (meth) acrylic acid ester may be the same compound as the fluorine-containing (meth) acrylic acid ester contained in the fluorine-containing monomer mixture.

  As a polymerization method of (meth) acrylic acid ester, known methods such as emulsion polymerization and suspension polymerization can be used, but the particle diameter uniformity of (meth) acrylic acid ester polymer particles and the simplicity of the production method. In view of the above, emulsion polymerization is preferred. Although the method using emulsion polymerization is described below, it is not limited to this method.

  When (meth) acrylic acid ester is emulsion polymerized to obtain (meth) acrylic acid ester polymer particles, first, (meth) acrylic acid ester is dispersed in an aqueous medium to prepare an aqueous emulsion.

  Examples of the aqueous medium include the above-described medium. A surfactant described later in the section of [Seed polymerization step] may be added to the aqueous medium. The aqueous emulsion can be prepared, for example, by the method using the fine emulsifier described above.

  You may mix the polymerization initiator mentioned above with (meth) acrylic acid ester as needed. The polymerization initiator may be mixed in advance in (meth) acrylic acid ester and then dispersed in an aqueous medium, or may be mixed in which both are separately dispersed in an aqueous medium. It is preferable to use a polymerization initiator in the range of 0.1-3 mass parts with respect to 100 mass parts of (meth) acrylic acid ester.

  The polymerization of (meth) acrylic acid ester is preferably performed in the presence of the chain transfer agent described above. As the chain transfer agent, mercaptans are preferable, and n-octyl mercaptan is particularly preferable. The chain transfer agent is preferably used within a range of 0.1 to 0.9 parts by mass with respect to 100 parts by mass of the (meth) acrylic acid ester, and 100 parts by mass of the (meth) acrylic acid ester. On the other hand, it is more preferably used within the range of 0.1 to 0.5 parts by mass. As a result, phase separation between the seed particles and the (meth) acrylic monomer mixture is likely to occur, and an irregular shape unique to the present invention is easily formed.

  Next, (meth) acrylic acid ester polymer particles are obtained by polymerizing the (meth) acrylic acid ester in the aqueous emulsion. The polymerization temperature can be appropriately selected according to the type of (meth) acrylic acid ester and the type of polymerization initiator. The polymerization temperature is preferably 25 to 110 ° C, more preferably 50 to 100 ° C. After completion of the polymerization, the (meth) acrylic acid ester polymer particles are separated from the aqueous medium by filtration or the like, and the aqueous medium is removed from the (meth) acrylic acid ester polymer particles by centrifugation or the like as necessary. Wash with water and solvent, then dry.

  As described above, (meth) acrylic acid ester polymer particles are obtained. In addition, the magnitude | size and shape of a (meth) acrylic acid ester polymer particle are not specifically limited. For the (meth) acrylic acid ester polymer particles, spherical particles having a particle diameter of 0.1 to 5 μm are usually used.

[Seed polymerization process]
In the seed polymerization step (second step), the seed particles (resin particles) absorb a (meth) acrylic monomer mixture containing 1 to 50% by mass of a polyfunctional monomer and then polymerize. Thus, irregular shaped resin particles are obtained.

  The (meth) acrylic monomer mixture contains at least a (meth) acrylic acid ester and a polyfunctional monomer, and has different components from the fluorine-containing monomer mixture. The (meth) acrylic acid ester is a monofunctional (meth) acrylic acid ester having one polymerizable alkenyl group (broadly-defined vinyl group) in one molecule. Examples of the (meth) acrylic acid ester include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, 2-hydroxylethyl (meth) ) Acrylate, glycidyl (meth) acrylate, (meth) acrylic acid ester having an alkylene oxide group, and the like. These monomers may use only 1 type and may mix and use 2 or more types. The (meth) acrylic acid ester is preferably a (meth) acrylic acid ester other than a fluorine-containing (meth) acrylic acid ester, a linear alkyl (meth) acrylate, a (meth) acrylic acid ester having a hydroxyl group, or a glycidyl group. More preferred are (meth) acrylic acid esters having and (meth) acrylic acid esters having an alkylene oxide group. As a result, phase separation between the seed particles and the (meth) acrylic monomer mixture is likely to occur, and an irregular shape unique to the present invention is easily formed.

  Examples of the (meth) acrylic acid ester having an alkylene oxide group include compounds of the following formula (1).

In the formula, R ₁ is H or CH ₃ , R ₂ and R ₃ are different alkylene groups selected from C ₂ H ₄ , C ₃ H ₆ , C ₄ H ₈ , C ₅ H ₁₀ , m 0 to 50, n is 0 to 50 (where m and n are not 0 simultaneously), and R ₄ is H or CH ₃ . In addition, in the monomer of Formula (1), when m is larger than 50 and when n is larger than 50, the polymerization stability may be lowered and coalescence particles may be generated. The preferable range of m and n is 0-30, and the more preferable range of m and n is 0-15.

Examples of the (meth) acrylic acid ester having an alkylene oxide group include Blemmer (registered trademark) series manufactured by NOF Corporation, for example, Blemmer (registered trademark) 50PEP-300 (R ₁ is CH ₃ , R ₂ is C ₂ H ₅ , R ₃ is C ₃ H ₆ , m and n are on average a mixture of m = 3.5 and n = 2.5, R ₄ is H), Blemmer® 70 PEP-350B (R ₁ is CH ₃ , R ₂ is C ₂ H ₅ , R ₃ is C ₃ H ₆ , m and n are on average a mixture of m = 5 and n = 2, R ₄ is H), Blemmer® PP-1000 (R ₁ is CH ₃ , R ₃ is C ₃ H ₆ , m is 0, n is a mixture of 4 to 6 on average, R ₄ is H), Blemmer ( PME-400 (R ₁ is CH ₃ , R ₂ is C ₂ H ₅ , m is a mixture of 9 on average, n is 0, R ₄ is CH ₃ ) and the like.

  The polyfunctional monomer is a compound having two or more polymerizable alkenyl groups (broadly defined vinyl groups) in one molecule. Examples of the polyfunctional monomer include ethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, divinylbenzene, and the like. The amount of the polyfunctional monomer used is 1 to 50% by mass with respect to the total amount of the (meth) acrylic monomer mixture, but with respect to the total amount of the (meth) acrylic monomer mixture. It is more preferable that it is 20-50 mass%. When the amount of the polyfunctional monomer used is 20% by mass or more based on the total amount of the (meth) acrylic monomer mixture, phase separation between the seed particles and the (meth) acrylic monomer mixture It is presumed that this easily occurs and it becomes easy to form a deformed shape peculiar to the present invention.

  The (meth) acrylic monomer mixture may contain a monofunctional monomer other than the (meth) acrylic acid ester. Examples of monofunctional monomers other than (meth) acrylic acid esters include (meth) acrylic acid; (meth) acrylamide; vinyl acetate; acrylonitrile. These compounds may be used alone or in combination of two or more. It is preferable that the usage-amount of monofunctional monomers other than (meth) acrylic acid ester is 20 mass% or less with respect to the whole quantity of the said (meth) acrylic-type monomer mixture, and is 10 mass% or less. More preferably.

  In the seed polymerization step, an aqueous emulsion is prepared by dispersing a (meth) acrylic monomer mixture in an aqueous medium. Examples of the aqueous medium include the above-described medium. The aqueous emulsion can be prepared, for example, by the method using the fine emulsifier described above.

  The aqueous emulsion preferably contains a surfactant. As the surfactant, any of an anionic surfactant, a cationic surfactant, a nonionic surfactant, and a zwitterionic surfactant can be used.

  Examples of anionic surfactants include fatty acid oils such as sodium oleate and castor oil, alkyl sulfate salts such as sodium lauryl sulfate and ammonium lauryl sulfate, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, and alkylnaphthalene sulfone. Acid salts, alkane sulfonates, dialkyl sulfosuccinates such as sodium dioctyl sulfosuccinate, alkenyl succinates (dipotassium salts), alkyl phosphate esters, naphthalene sulfonate formalin condensates, polyoxyethylene alkylphenyl ether sulfates Examples thereof include salts, polyoxyethylene alkyl ether sulfates such as sodium polyoxyethylene lauryl ether sulfate, and polyoxyethylene alkyl sulfate salts.

  Examples of the cationic surfactant include alkylamine salts such as laurylamine acetate and stearylamine acetate, and quaternary ammonium salts such as lauryltrimethylammonium chloride. Examples of zwitterionic surfactants include lauryl dimethylamine oxide and phosphate ester or phosphite ester surfactants. You may use the said surfactant individually or in combination of 2 or more types. Among the surfactants, anionic surfactants are preferable from the viewpoint of dispersion stability during polymerization.

  The (meth) acrylic monomer mixture may contain a polymerization initiator as necessary. The polymerization initiator may be preliminarily mixed in the (meth) acrylic monomer mixture and then dispersed in an aqueous medium, or may be mixed in which both are separately dispersed in an aqueous medium. When the particle diameter of the droplets of the (meth) acrylic monomer mixture in the obtained aqueous emulsion is smaller than the seed particles, the (meth) acrylic monomer mixture is more efficiently absorbed by the seed particles. Therefore, it is preferable.

  The seed particles may be added directly to the aqueous emulsion, or may be added in a form in which the seed particles are dispersed in an aqueous medium. After the seed particles are added to the aqueous emulsion, the (meth) acrylic monomer mixture is absorbed into the seed particles. This absorption can usually be performed by stirring the aqueous emulsion after addition of seed particles at room temperature (about 20 ° C.) for 1 to 12 hours. Moreover, you may accelerate | stimulate absorption by heating an aqueous emulsion to about 30-50 degreeC.

  The seed particles swell due to absorption of the (meth) acrylic monomer mixture. The amount of the (meth) acrylic monomer mixture absorbed in 1 part by mass of the seed particles is preferably in the range of 2 to 125 parts by mass, more preferably in the range of 2 to 50 parts by mass, More preferably, it is in the range of 2 to 30 parts by mass. When the amount of the (meth) acrylic monomer mixture absorbed in 1 part by mass of the seed particles is within the range of 2 to 125 parts by mass, the ratio D / of the major axis D of the resin core 2 to the major axis A of the deformed resin particles Since it is easy to obtain odd-shaped resin particles having A in the range of 0.2 to 0.7, the light diffusibility can be further improved. When the amount of the (meth) acrylic monomer mixture absorbed in 1 part by mass of the seed particles is 2 parts by mass or more, the increase in the particle diameter due to seed polymerization becomes sufficiently large, and the productivity is improved. When the amount of the (meth) acrylic monomer mixture absorbed in 1 part by mass of the seed particles is 50 parts by mass or less, the (meth) acrylic monomer mixture is not absorbed by the seed particles in the aqueous medium. It is possible to avoid the generation of abnormal particles by independent suspension polymerization.

  A polymerization initiator can be mixed with the (meth) acrylic monomer mixture as necessary. Examples of the polymerization initiator include benzoyl peroxide, lauroyl peroxide, orthochlorobenzoyl peroxide, orthomethoxybenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, tert-butylperoxy-2-ethylhexano Organic peroxides such as ate and di-t-butyl peroxide; 2,2′-azobisisobutyronitrile, 1,1′-azobiscyclohexanecarbonitrile, 2,2′-azobis (2,4- And azo compounds such as dimethylvaleronitrile). The polymerization initiator is preferably used within a range of 0.1 to 3 parts by mass with respect to 100 parts by mass of the (meth) acrylic monomer mixture.

  In the seed polymerization step, a polymer dispersion stabilizer may be added to the aqueous emulsion in order to improve the dispersion stability of the formed irregular shaped resin particles. Examples of the polymer dispersion stabilizer include polyvinyl alcohol, polycarboxylic acid, celluloses (such as hydroxyethyl cellulose and carboxymethyl cellulose), and polyvinyl pyrrolidone. Also, a polymer dispersion stabilizer and an inorganic water-soluble polymer compound such as sodium tripolyphosphate can be used in combination. Of these polymer dispersion stabilizers, polyvinyl alcohol and polyvinyl pyrrolidone are preferred. The addition amount of the polymer dispersion stabilizer is preferably in the range of 1 to 10 parts by mass with respect to 100 parts by mass of the (meth) acrylic monomer mixture.

  In the seed polymerization step, in order to suppress the generation of emulsified particles in the aqueous system, the aqueous emulsion is mixed with nitrites such as sodium nitrite, sulfites, hydroquinones, ascorbic acids, water-soluble vitamin Bs, Water-soluble polymerization inhibitors such as acids and polyphenols may be added. It is preferable that the addition amount of a polymerization inhibitor exists in the range of 0.02-0.2 mass part with respect to 100 mass parts of (meth) acrylic-type monomer mixtures.

  Next, the shaped resin particles are obtained by polymerizing the (meth) acrylic monomer mixture absorbed in the seed particles. The polymerization temperature can be appropriately selected depending on the type of (meth) acrylic monomer mixture and the type of polymerization initiator. The polymerization temperature is preferably in the range of 25 to 110 ° C, and more preferably in the range of 50 to 100 ° C. The polymerization reaction is preferably performed by raising the temperature after the (meth) acrylic monomer mixture is completely absorbed by the seed particles. After completion of the polymerization, the irregular shaped resin particles are separated from the aqueous medium by filtration or the like, and if necessary, the aqueous medium is removed from the irregular shaped resin particles by centrifugation or the like, and if necessary, washed with water and a solvent and then dried.

  As described above, the resin layer that forms the surface layer of the irregularly shaped resin particles, and the irregularly shaped resin particles that include the resin core that is formed of the resin component different from the resin layer and is formed inside the resin layer, According to the present invention, the resin core has a single depression, the resin core is present adjacent to the depression, and the deformed resin particles close to a spherical shape, in particular, the ratio B / A of the minor axis B to the major axis A is 0.7 or more. Deformed resin particles can be created.

[External preparation]
The irregularly shaped resin particles of the present invention can be used as a raw material for external preparations, for example, as a slipperiness improver for external preparations. The external preparation of the present invention contains the irregular shaped resin particles of the present invention. The content of the irregularly shaped resin particles in the external preparation can be appropriately set according to the type of the external preparation, but is preferably in the range of 1 to 80% by mass, and more preferably in the range of 5 to 70% by mass. When the content of the irregular shaped resin particles with respect to the total amount of the external preparation is less than 1% by mass, a clear effect due to the inclusion of the irregular shaped resin particles may not be recognized. On the other hand, if the content of the irregular shaped resin particles exceeds 80% by mass, a remarkable effect corresponding to 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 deformed resin particles. For example, liquid systems such as pre-shave lotion, body lotion, lotion, cream, milky lotion, body shampoo, antiperspirant, etc. Cosmetics for soap, scrubs, facial cleansers, etc .; packs; shaving creams; funny products; foundations; lipsticks; Aromatic cosmetics; toothpaste; bath preparation; sunscreen product; suntan product; body powder, baby powder and other body cosmetics.

  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.), color material (red iron oxide, yellow iron oxide, etc.), flavor, antiseptic / sterilization Agent, antioxidant, UV absorber, acrylic resin particles (poly (meth) acrylate particles), silicone particles, Resin particles such as styrene particles, irregular resin particles other than irregular resin particles of the present invention, pH adjusting agents (triethanolamine), a special formulation additives, pharmaceutical active ingredients, and the like.

〔paint〕
The irregular shaped resin particles of the present invention can be contained in a paint as a coating film softening agent or a paint matting agent. The paint contains the irregular shaped resin particles of the present invention. The paint contains at least one of a binder resin and a solvent as necessary. As the binder resin, a resin soluble in an organic solvent or water, or an emulsion-type aqueous resin that can be dispersed in water can be used. Examples of such binder resins include acrylic resins, alkyd resins, polyester resins, polyurethane resins, chlorinated polyolefin resins, and amorphous polyolefin resins. These binder resins can be appropriately selected depending on the adhesion of the paint to the substrate to be coated, the environment in which it is used, and the like.

  The addition amount of the binder resin and the deformed resin particles varies depending on the film thickness of the formed coating film, the average particle diameter of the deformed resin particles, and the coating method. The addition amount of the binder resin is preferably in the range of 5 to 50% by mass with respect to the total of the binder resin (solid content when an emulsion-type aqueous resin is used) and the deformed resin particles. It is more preferably in the range of ˜50% by mass, and further preferably in the range of 20˜40% by mass.

  The added amount of the irregular shaped resin particles is preferably in the range of 5 to 50% by mass with respect to the total of the binder resin (solid content when using an emulsion type aqueous resin) and the irregular shaped resin particles, It is more preferably in the range of 10 to 50% by mass, and further preferably in the range of 20 to 40% by mass. When the content of the irregular shaped resin particles is less than 5% by mass, the matte effect may not be sufficiently obtained. On the other hand, when the content of the irregular shaped resin particles exceeds 50% by mass, the dispersion of the irregular shaped resin particles may occur because the viscosity of the coating composition becomes too large. Therefore, the appearance defect of the coating film may occur, such as micro cracks occurring in the coating film obtained, or roughness on the surface of the coating film obtained.

  Although it does not specifically limit as a solvent which comprises the said coating material, It is preferable to use the solvent which can melt | dissolve or disperse | distribute binder resin. For example, when the paint is an oil paint, as the solvent, hydrocarbon solvents such as toluene and xylene; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; ester solvents such as ethyl acetate and butyl acetate; dioxane and ethylene And ether solvents such as glycol diethyl ether and ethylene glycol monobutyl ether. When the paint is an aqueous paint, water, alcohols, etc. can be used as the solvent. These solvents may be used alone or in combination of two or more. The content of the solvent in the coating is usually in the range of 20 to 60% by mass with respect to the total amount of the coating.

  The paint includes known coating surface modifiers, fluidity modifiers, ultraviolet absorbers, light stabilizers, curing catalysts, extender pigments, colored pigments, metal pigments, mica powder pigments, dyes, etc., as necessary. It may be.

  The formation method of the coating film using a coating material is not specifically limited, Any well-known method can be used. Examples of the method for forming the coating film include methods such as spray coating, roll coating, and brush coating. The paint may be diluted by adding a diluent to adjust the viscosity as necessary. Diluents include hydrocarbon solvents such as toluene and xylene; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; ester solvents such as ethyl acetate and butyl acetate; ether solvents such as dioxane and ethylene glycol diethyl ether; water An alcohol solvent or the like. These diluents may be used alone or in combination of two or more.

[Light diffusing resin composition]
By dispersing the irregular shaped resin particles of the present invention in a transparent base resin (transparent resin) as a light diffusing agent, it can be used as a light diffusing resin composition. That is, the light diffusing resin composition contains the irregular shaped resin particles of the present invention and a transparent base resin. The light diffusing resin composition is a raw material for lighting covers (light emitting diode (LED) lighting lighting covers, fluorescent lamp lighting lighting covers, etc.) and light diffusion members (light diffusion sheets, light diffusion films, light diffusion plates, etc.). Can be used as

  As the transparent base resin, a thermoplastic resin different from the component of the polymer particles constituting the irregular shaped resin particles is usually used. Examples of the thermoplastic resin used as the transparent base resin include acrylic resin, alkyl (meth) acrylate-styrene copolymer, polycarbonate, polyester, polyethylene, polypropylene, and polystyrene. Among these thermoplastic resins, acrylic resin, alkyl (meth) acrylate-styrene copolymer, polycarbonate, polyester, and polystyrene are preferable when excellent transparency is required for the transparent base resin. These thermoplastic resins can be used alone or in combination of two or more.

  The addition ratio of the irregular shaped resin particles to the transparent base resin is preferably in the range of 0.01 to 40 parts by weight, and in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the transparent base resin. More preferably, it is within. When the odd-shaped resin particles are less than 0.01 parts by mass, it may be difficult to impart light diffusibility to the light diffusing member. When the number of irregular shaped resin particles is more than 40 parts by mass, the light diffusing member can be given light diffusibility, but the light diffusing member may have low light transmittance.

  The method for producing the light diffusing resin composition is not particularly limited, and can be produced by mixing the irregularly shaped resin particles and the transparent base resin by a conventionally known method such as a mechanical pulverization and mixing method. In the mechanical pulverization and mixing method, for example, by using a device such as a Henschel mixer, a V-type mixer, a turbula mixer, a hybridizer, or a rocking mixer, the irregular shaped resin particles and the transparent base resin are mixed and stirred to obtain light. A diffusible resin composition can be produced.

  By molding the light diffusing resin composition, a light diffusing member such as a lighting cover or a light diffusing sheet according to the present invention can be produced. In this case, for example, a light diffusing agent and a transparent base resin are mixed with a mixer, and a pellet made of a light diffusing resin composition is obtained by kneading with a melt kneader such as an extruder. A light diffusing member having an arbitrary shape can be obtained by extrusion molding or injection molding after melting the pellet.

  The light diffusion sheet can be used as, for example, a light diffusion sheet of a liquid crystal display device. The configuration of the liquid crystal display device is not particularly limited as long as it includes a light diffusion sheet. For example, the liquid crystal display device includes at least a liquid crystal display panel having a display surface and a back surface, a light guide plate disposed on the back surface side of the liquid crystal display panel, and a light source that makes light incident on the side surface of the light guide plate. In addition, the liquid crystal display device includes a light diffusion sheet on a surface of the light guide plate facing the liquid crystal display panel, and a reflection sheet on the surface opposite to the surface of the light guide plate facing the liquid crystal display panel. This arrangement of light sources is generally referred to as an edge light type backlight arrangement. Furthermore, as the arrangement of the light source, there is a direct type backlight arrangement in addition to the edge light type backlight arrangement. Specifically, this arrangement is an arrangement in which a light source is arranged on the back side of the liquid crystal display panel and at least a light diffusion sheet arranged between the liquid crystal display panel and the light source.

[Light diffusing coating agent]
In the paint containing the irregular shaped resin particles, a transparent paint containing a binder resin, that is, a paint containing a transparent binder resin and not containing a non-transparent material such as a pigment or a dye is used for a paper coating agent or a light diffusion member. It can be used as a light diffusing coating agent such as a coating agent. In this case, the irregular shaped resin particles function as a light diffusing agent.

  The light diffusing member of the present invention is manufactured by coating a transparent base material as a base material with a light diffusing coating agent (light diffusing member coating agent) to form a transparent coating film (light diffusing coating). can do.

  As the transparent substrate, for example, a resin substrate made of a resin such as polyethylene terephthalate (PET), polyester, acrylic resin, polycarbonate, or polyamide, or an inorganic substrate such as a transparent glass sheet can be appropriately selected and used. The thickness of the transparent substrate is not particularly limited, but is preferably in the range of 10 to 500 μm in consideration of ease of processing and handling properties. As a method for forming the light diffusive coating, known methods such as reverse roll coating, gravure coating, die coating, comma coating, and spray coating can be used. The thickness of the light diffusive coating is not particularly limited, but is preferably in the range of 1 to 100 μm and preferably in the range of 3 to 30 μm in consideration of light diffusibility, film strength, and the like. Is more preferable.

  Matte paper can be produced by coating a light-diffusing coating agent (paper coating agent) on paper as a base material to form a transparent coating film. As the method for forming the coating film, the above-described method can be used, but it is preferable to use a method in which irregularities derived from the deformed resin particles are formed on the surface of the coating film. Moreover, as said transparent base resin, the transparent base resin used for the light diffusable resin composition mentioned above can be used. The light diffusing member obtained by coating the coating agent for the light diffusing member can be used as an antiglare film, and also used for the same use as the light diffusing member obtained by molding the light diffusing resin composition described above. be able to.

  Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited to this.

[Method for measuring average particle diameter of seed particles]
The average particle size of the seed particles was measured with a laser diffraction / scattering particle size distribution analyzer (LS230 type, manufactured by Beckman Coulter, Inc.). Specifically, 0.1 g of seed particles and 10 ml of 0.1% nonionic surfactant solution are put into a test tube and mixed for 2 seconds with a touch mixer (manufactured by Yamato Kagaku Co., Ltd., “TOUCHMIXER MT-31”). did. Thereafter, the seed particles in the test tube were dispersed for 10 minutes using a commercially available ultrasonic cleaner (“ULTRASONIC CLEARNER VS-150” manufactured by VervoCrea Inc.) to obtain a dispersion. While irradiating the dispersion with ultrasonic waves, the average particle size of the seed particles in the dispersion was measured with a laser diffraction / scattering particle size distribution analyzer (LS230, manufactured by Beckman Coulter, Inc.). The optical model at the time of measurement was adjusted to the refractive index of the produced seed particles. When one kind of monomer was used for the production of seed particles, the refractive index of the homopolymer of the monomer was used as the refractive index of the seed particles. When multiple types of monomers are used in the production of seed particles, the average value obtained by weighted average of the refractive index of the homopolymer of each monomer by the amount of each monomer used as the refractive index of the seed particles Was used.

[Measurement method of average particle diameter of irregular shaped resin particles]
The average particle size of the irregular shaped resin particles was measured by a Coulter method using a Coulter type precision particle size distribution analyzer Multisizer II (manufactured by Beckman Coulter, Inc.). According to the measurement method, according to Reference MANUAL FOR THE COULTER MULTISIZER (1987) published by Coulter Electronics Limited, Multisizer II was calibrated using a 50 μm aperture, and the average particle size was measured.

  Specifically, 0.1 g of irregularly shaped resin particles was dispersed in 10 ml of a 0.1% nonionic surfactant aqueous solution using a touch mixer and ultrasonic waves to obtain a dispersion. The dispersion is dropped into a beaker filled with the measurement electrolyte “ISOTON (registered trademark) II” (manufactured by Beckman Coulter, Inc.) attached to the Multisizer II body with a dropper while gently stirring, and the Multisizer The reading of the densitometer on the screen of the II main body was adjusted to around 10%. Next, enter Multisizer II body with an aperture size (diameter) of 50 μm, a current (aperture current) of 800 μA, a gain of 4, and a Polarity (polarity of the inner electrode) of + (manual mode) ) To measure the volume-based particle size distribution. The aperture size and the like can be changed and input as necessary. During the measurement, the beaker was stirred gently to the extent that no bubbles were introduced, and the measurement was terminated when the particle size distribution of 100,000 particles was measured. The arithmetic average diameter in the measured volume-based particle size distribution was defined as the average particle diameter.

[Measurement method of coefficient of variation (CV value) of particle diameter of irregular shaped resin particle]
The CV value of the particle diameter of the irregularly shaped resin particles was calculated from the standard deviation (σ) and the average particle diameter (D) when the above-mentioned volume-based particle size distribution was measured by the following formula.

CV value (%) = (σ / D) × 100
[Seed Particle Production Example 1]
First, 3500 g of pure water as an aqueous medium was put into a reactor equipped with a stirrer and a thermometer. Subsequently, 396 g of methyl methacrylate as a (meth) acrylic acid ester and 1.2 g of n-octyl mercaptan as a chain transfer agent were added to pure water in the reactor. Subsequently, a nitrogen purge (nitrogen replacement) was performed, and the temperature was raised to 55 ° C. Thereafter, a solution obtained by dissolving 2.0 g of potassium persulfate as a polymerization initiator in 100 g of pure water was added to the contents in the reactor, and nitrogen purge was performed again. Thereafter, polymerization was carried out at 55 ° C. for 12 hours while stirring to obtain seed particles (hereinafter referred to as “seed particles (1)”) in a slurry state. When the average particle diameter of the seed particles (1) was measured by the method described above, the average particle diameter of the seed particles (1) was 0.45 μm.

[Seed Particle Production Example 2]
First, 3500 g of pure water as an aqueous medium was put into a reactor equipped with a stirrer and a thermometer. Next, 396 g of trifluoroethyl methacrylate as a fluorine-containing (meth) acrylic acid ester and 4 g of ethylene glycol dimethacrylate as a polyfunctional monomer (based on the total amount of the monomer mixture) were added to pure water in the reactor. 1 mass%), 1.2 g of n-octyl mercaptan as a chain transfer agent, and 285 g of seed particles (1) obtained in seed particle production example 1 as a polymer of (meth) acrylic acid ester did. Subsequently, the reactor was purged with nitrogen and heated to 55 ° C. Thereafter, a solution obtained by dissolving 2.0 g of potassium persulfate as a polymerization initiator in 100 g of pure water was added to the contents in the reactor, and nitrogen purge was performed again. Thereafter, polymerization was carried out at 55 ° C. for 12 hours with stirring to obtain seed particles (hereinafter referred to as “seed particles (2)”) in a slurry state. When the average particle diameter of the seed particles (2) was measured by the method described above, the average particle diameter of the seed particles (2) was 1.0 μm.

[Seed Particle Production Example 3]
Seed particles were produced in the same manner as in Seed Particle Production Example 2, except that 396 g of methyl methacrylate was used instead of 396 g of trifluoroethyl methacrylate. Thereby, seed particles (hereinafter referred to as “seed particles (3)”) were obtained in a slurry state. When the average particle diameter of the seed particles (3) was measured by the method described above, the average particle diameter of the seed particles (3) was 1.0 μm.

[Example 1]
First, 80 g of ion-exchanged water as an aqueous medium is placed in a reactor equipped with a high-speed stirrer and a thermometer, and then sodium dioctylsulfosuccinate as an anionic surfactant (product) is added to the ion-exchanged water in the reactor. 0.8 g of the name “Lapisol (registered trademark) A-80” (manufactured by NOF Corporation) was added. Thereafter, the contents of the reactor were charged with 56 g of methyl methacrylate as a monofunctional (meth) acrylic acid ester and 24 g of ethylene glycol dimethacrylate as a polyfunctional monomer (30% based on the total amount of the monomer mixture). Mass%) and 0.5 g of benzoyl peroxide as a polymerization initiator were added, and the mixture was stirred with a high-speed stirrer at a stirring speed of 8000 rpm for 10 minutes to obtain an emulsion.

  Thereafter, 36.6 g of seed particles (2) obtained in Seed Particle Production Example 2 were added to the emulsion, and the seed particles (2) were allowed to absorb the emulsion over 2 hours at 30 ° C. The particles (2) were swollen. Thereafter, 240 g of ion-exchanged water as an aqueous medium and 3.2 g of polyvinyl alcohol as a polymer dispersion stabilizer are added to the reactor contents, and 0.064 g of sodium nitrite as a polymerization inhibitor is further added. Then, polymerization was carried out at 50 ° C. for 6 hours with stirring. By filtering the reaction solution after polymerization, the resin particles were separated from the reaction solution. The separated resin particles were thoroughly washed with warm water and then dried to obtain resin particles.

  The obtained resin particle was imaged with the scanning electron microscope (SEM), and the SEM image of FIG. 2 was obtained. It was. Further, a thin slice including the center of the resin particle was cut out from the obtained resin particle, the thin slice was stained and imaged with a transmission electron microscope (TEM), and the TEM image of FIG. 3 was obtained. It was. From the SEM image in FIG. 2 and the TEM image in FIG. 3, it was found that the resin particles were irregular shaped resin particles having a single depression. Further, from the TEM image of FIG. 3, the deformed resin particles include a resin layer (a black portion surrounding a white portion in FIG. 3) that forms the surface layer of the deformed resin particles, and a resin core formed inside the resin layer. (A white portion in FIG. 3 and a black portion surrounded by the white portion). Further, from the TEM image of FIG. 3, it was found that the resin core of the odd-shaped resin particles had a shape in which a part of the ellipsoid was missing (ellipsoidal shape) and was adjacent to the depression.

  Further, the major axis A and minor axis B of the irregular shaped resin particles were measured from the TEM image in FIG. 3 (the scale bar at the lower end is 500 nm), and the ratio B / A of the minor axis B to the major axis A was determined. B / A was 0.88. Further, the diameter C of the dent was measured from the TEM image of FIG. 3 and the ratio C / A of the diameter C of the dent to the major axis A was determined. The ratio C / A was 0.33. Further, the major axis D of the resin core was measured from the TEM image of FIG. 3, and the ratio D / A of the major axis D of the resin core to the major axis A of the irregular shaped resin particles was determined. The ratio D / A was 0.53. .

  Moreover, when the average particle diameter of the obtained irregular shaped resin particle was measured by the above-mentioned method, the average particle diameter of the irregular shaped resin particle was 2.5 μm. Further, when the CV value of the particle diameter of the obtained irregular shaped resin particles was measured by the above-mentioned method, the CV value of the particle diameter of the irregular shaped resin particles was 12%, and it was found that the irregular shaped resin particles were monodisperse particles. It was.

[Example 2]
Resin particles were produced by the same production method as in Example 1 except that 56 g of butyl methacrylate was used instead of 56 g of methyl methacrylate as the monofunctional (meth) acrylic acid ester.

  The obtained resin particles were imaged with SEM, and the SEM image of FIG. 4 was obtained. Further, a thin slice including the center of the resin particle was cut out from the obtained resin particle, and the thin slice was stained and imaged with TEM. From the SEM image of FIG. 4 and the TEM image (not shown), it was found that the resin particles are odd-shaped resin particles having a single depression. Further, from the TEM image, it was found that the deformed resin particles include a resin layer that forms a surface layer of the deformed resin particles and a resin core formed inside the resin layer. Further, from the TEM image, it was found that the resin core of the odd-shaped resin particles has an elliptical shape and is adjacent to the depression.

  Moreover, when the major axis A and minor axis B of the irregular shaped resin particles were measured from the TEM image and the ratio B / A of the minor axis B to the major axis A was determined, the ratio B / A was 0.82. Moreover, when the diameter C of the hollow was measured from the TEM image and the ratio C / A of the diameter C of the hollow with respect to the major axis A was determined, the ratio C / A was 0.16. Moreover, when the major axis D of the resin core was measured from the TEM image and the ratio D / A of the major axis D of the resin core to the major axis A of the irregular shaped resin particles was determined, the ratio D / A was 0.56.

  Moreover, when the average particle diameter of the obtained irregular shaped resin particle was measured by the above-mentioned method, the average particle diameter of the irregular shaped resin particle was 2.5 μm. Further, when the CV value of the particle diameter of the obtained irregular shaped resin particles was measured by the above-mentioned method, the CV value of the particle diameter of the irregular shaped resin particles was 12%, and it was found that the irregular shaped resin particles were monodisperse particles. It was.

  In Example 1 and Example 2, the ratio B / A of the minor diameter B of the irregular shaped resin particle to the major axis A of the irregular shaped resin particle, the ratio C / A of the hollow diameter C to the major diameter A of the irregular shaped resin particle, and the irregular shaped resin particle Table 1 summarizes the values of the ratio D / A of the major axis D of the resin core to the major axis A.

[Comparative Example 1]
Resin particles were produced by the same production method as in Example 1 except that 36.6 g of seed particles (3) obtained in Seed Particle Production Example 3 were used instead of 36.6 g of seed particles (2).

  The obtained resin particles were imaged with an SEM to obtain the SEM image of FIG. Further, a thin slice including the center of the resin particle was cut out from the obtained resin particle, and the thin slice was stained and imaged with TEM. From the SEM image and the TEM image, it was found that the resin particles are homogeneous spherical resin particles having no depression.

[Measurement of oil absorption]
Based on the measurement method of JIS K 5101-13-2, the primary linseed oil is used instead of the boiled linseed oil and the end point is determined based on the oil absorption amount of the resin particles of Example 1, Example 2 and Comparative Example 1. The measurement was performed by a method in which the reference was changed (changed to a point in time when the sample did not flow even if the measurement plate was set up). Details of the oil absorption measurement are as follows.

(A) Apparatus and instrument Measuring plate: Smooth glass plate larger than 300 x 400 x 5 mm Pallet knife (scalar): With handle with steel or stainless steel blade Chemical scale (meter): Can measure up to 10 mg order Things Bullet: 10 ml capacity specified in JIS R 3505 (B) Reagent First grade linseed oil: Wako Pure Chemical Industries, Ltd. (C) Measuring method
(1) Take 1 g of resin particles in the center of the measuring plate and drop 4 or 5 drops of primary linseed oil from the burette at a time into the center of the resin particles. Each time, resin particles and primary linseed oil are added. Knead the whole with a pallet knife.

  (2) Repeat the above dripping and kneading, and if the resin particles and primary linseed oil become a hard putty-like lump, knead each drop and paste (resin particles) by adding the last drop of primary linseed oil. And the kneaded mixture of first grade linseed oil) is softened suddenly, and the end point is the point where flow begins.

(3) Determination of flow It is determined that the paste is flowing when the last drop of primary linseed oil drastically softens and the paste moves when the measuring plate is set up vertically. If the paste does not move when the measuring plate is erected vertically, add another drop of primary linseed oil.

  (4) Read the consumption of the first grade linseed oil when the end point is reached as the decrease in the liquid volume in the burette.

  (5) The measurement time for one measurement should be completed within 7 to 15 minutes. If the measurement time exceeds 15 minutes, it will be re-measured, and the value when the measurement is completed within the specified time will be adopted. To do.

(D) Calculation of oil absorption amount Oil absorption amount per 100 g of sample is calculated by the following formula.

O = (V / m) × 100
Here, O: oil absorption (ml / 100 g), m: mass of resin particles (g), V: volume of consumed primary linseed oil (ml)
The results of measuring the oil absorption of the resin particles of Example 1, Example 2, and Comparative Example 1 are shown in Table 2. In addition, the value of the oil absorption amount shown in Table 2 is an average value obtained by measuring the oil absorption amount of each resin particle three times and averaging the measured values.

[Measurement of specific surface area]
The specific surface area of the resin particle of Example 1, Example 2, and Comparative Example 1 was manufactured by Shimadzu Corporation as a measuring instrument by the BET (Brunauer-Emmett-Teller) method (nitrogen adsorption method) described in JIS R 1626. The specific surface area / pore distribution measuring device “TriStar (registered trademark) 3000” was used. For the target resin particles, the BET nitrogen adsorption isotherm was measured using the above-mentioned automatic specific surface area / pore distribution measuring device “Tristar (registered trademark) 3000”, and the specific surface area was determined from the nitrogen adsorption amount using the BET multipoint method. Was calculated. The nitrogen adsorption isotherm was measured using nitrogen as an adsorbate and a constant volume method under the condition of an adsorbate cross section of 0.162 nm ² .

  Table 2 shows the results of measuring the specific surface areas of the resin particles of Example 1, Example 2, and Comparative Example 1. In addition, the value of the specific surface area shown in Table 2 is an average value obtained by measuring the specific surface area of each resin particle three times and averaging the measured values.

  The irregular shaped resin particles of Example 1 and Example 2 had a larger specific surface area and higher oil absorption than the true spherical resin particles of Comparative Example 1.

  This is because the irregular shaped resin particles of Example 1 and Example 2 have depressions, so that the specific surface area is larger than the true spherical resin particles of Comparative Example 1, and the oil absorption area is also increased accordingly. . Therefore, when the irregular shaped resin particles of Example 1 and Example 2 are used for external preparations such as cosmetic liquids and paints, the surface of the resin particles in contact with the medium (solvent, etc.) becomes large, leading to the medium (other components). It is considered that the familiarity of the resin particles is improved (the falling of the resin particles is reduced, etc.).

[Example 3: Compounding of irregularly shaped resin particles in external preparation]
A body lotion as an example of the external preparation of the present invention was prepared by mixing 2 g of irregularly shaped resin particles of Example 1, 9 g of ion-exchanged water, and 1 g of ethanol as a lower alcohol.

[Example 4: Compounding of irregularly shaped resin particles in external preparation]
A body lotion as an example of the external preparation of the present invention was prepared in the same manner as in Example 3 except that the irregularly shaped resin particles of Example 2 were used in place of the irregularly shaped resin particles of Example 1.

[Comparative Example 2]
Example 3 except that the spherical resin particles of Comparative Example 1 were used in place of the irregularly shaped resin particles of Example 1.
In the same way, a body lotion for comparison was created.

[Evaluation of moisturizing properties (moist feeling)]
When the body lotions of Example 3, Example 4, and Comparative Example 2 were applied to the wrist, sensory evaluation was performed by ten panelists on the moist feeling when touched with a finger. The moist sensory evaluation result was calculated as an average value of evaluation values by the following five-step evaluation.

1 ... very moist 2 ... moist 3 ... slightly moist 4 ... slightly moist 5 ... not moist at all Example 3, Table 3 shows sensory evaluation results of moist feeling for the body lotions of Example 4 and Comparative Example 2.

  The moisture retention of the body lotion was correlated with the result of the oil absorption of the resin particles, and the result was that the moisture retention of the body lotion was higher as the specific surface area of the resin particles was larger. The moisture retention of the body lotion of Example 3 and Example 4 was superior to the moisture retention of the body lotion of Comparative Example 2.

[Example 5: Preparation of light diffusing film]
A mixture obtained by mixing 20 parts by mass of irregularly shaped resin particles of Example 1 and 20 parts by mass of an acrylic binder (trade name: Dianal (registered trademark) BR-116, manufactured by Mitsubishi Rayon Co., Ltd.) as a binder resin. On the other hand, 180 parts by mass of a mixed solvent in which toluene and methyl ethyl ketone were mixed at a volume ratio of 1: 1 was added and stirred for 3 minutes with a centrifugal stirrer to obtain a solution. This solution was allowed to stand for 3 hours and then stirred again for 3 minutes with a centrifugal stirrer to obtain a solution (light diffusible coating agent) as an example of the paint of the present invention. Thereafter, the obtained solution was coated on a 100 μm thick PET film as a transparent substrate using a 75 μm coater. The obtained film was dried for 1 hour in a drier kept at 70 ° C. to obtain a light diffusion film having a total thickness (dry film thickness) of about 110 μm to 120 μm as an example of the light diffusion member of the present invention.

[Example 6: Preparation of light diffusion film]
A light diffusing film as an example of the light diffusing member of the present invention was obtained in the same manner as in Example 5 except that the deformed resin particles of Example 2 were used instead of the deformed resin particles of Example 1.

[Comparative Example 3]
A comparative light diffusion film was obtained in the same manner as in Example 5 except that the resin particles of Comparative Example 1 were used in place of the irregularly shaped resin particles of Example 1.

[Test of scratch resistance of resin for light diffusion film (removability of resin particles)]
The surface of the resin particle-containing layer in the light diffusing films of Example 5, Example 6, and Comparative Example 3 was reciprocally polished 20 times with a cloth using a friction fastness tester. Was visually observed.

  When the polished light diffusing film has 3 or less scratches, the scratch resistance is “◯”, and when 4 to 9 scratches are seen, the scratch resistance is “Δ”. Scratch resistance was determined to be “x” when 10 or more flaws were observed.

  The irregular shaped resin particles of Example 1 having a larger specific surface area are more familiar with the binder resin and less fallen from the light diffusion film than the spherical resin particles of Comparative Example 1 having a smaller specific surface area. Thus, it was confirmed that the surface of the light diffusion film was less likely to be scratched (the scratch resistance of the light diffusion film was improved).

[Evaluation of light diffusibility of light diffusion film]
The light diffusibility of the light diffusion films of Example 5, Example 6, and Comparative Example 3 was evaluated by measuring haze. The haze was measured by a method according to JIS K 7136, using a haze meter “NDH2000” manufactured by Nippon Denshoku Industries Co., Ltd. as a measuring instrument. In addition, the value of haze shown in Table 5 is an average value obtained by measuring the haze of each light diffusion film three times and averaging the measured values.

  When the light diffusion films of Example 5 and Example 6 were compared with the light diffusion film of Comparative Example 3, the light diffusion films of Example 5 and Example 6 were higher than the light diffusion film of Comparative Example 3. Haze value was shown. This difference is considered to be caused by the shape of the resin particles of Example 1 and Example 2 (shape having depressions). In addition, the deformed resin particles produced by the method (seed polymerization method) shown in Example 1 and Example 2 have a monomer composition of the resin core (core particle) and a monomer composition of the resin layer (surface resin). Due to the difference, it has been confirmed that a high haze value is exhibited.

  From this result, it can be seen that the irregular shaped resin particles of Example 1 and Example 2 are suitable for the use of a light diffusion member such as a light diffusion film or a light diffusion plate. In addition, the irregular shaped resin particles of Example 1 and Example 2 are excellent in concealability caused by the difference in refractive index between the resin core and the resin layer, and can be expected to be useful for the use of external preparations such as cosmetics.

1 Resin layer 2 Resin core 3 Dimple

Claims (12)

A resin layer that forms the surface layer of the deformed resin particles;
The resin layer is formed of a resin component different from the resin layer, and is a deformed resin particle including a resin core formed inside the resin layer,
Has a single depression,
The resin core has an ellipsoid shape and is adjacent to the depression;
The odd-shaped resin particle, wherein the ratio B / A of the minor diameter B of the irregular-shaped resin particle to the major axis A of the irregular-shaped resin particle is 0.7 or more. The deformed resin particle according to claim 1,
The odd-shaped resin particle, wherein the ratio B / A of the minor diameter B of the irregular-shaped resin particle to the major axis A of the irregular-shaped resin particle is 0.9 or less. The deformed resin particle according to claim 1 or 2,
A deformed resin particle, wherein a ratio C / A of the diameter C of the recess to the major axis A of the deformed resin particle is in a range of 0.1 to 0.4. The deformed resin particle according to any one of claims 1 to 3,
The odd-shaped resin particles, wherein the ratio D / A of the major axis D of the resin core to the major axis A of the irregular-shaped resin particles is in the range of 0.2 to 0.7. The deformed resin particle according to any one of claims 1 to 4,
The deformed resin particles, wherein the resin layer and the resin core are made of a (meth) acrylic ester resin. The deformed resin particle according to any one of claims 1 to 5,
The deformed resin particles, wherein the resin layer is crosslinked with 1 to 50% by mass of a polyfunctional monomer with respect to the total mass of the resin layer. The deformed resin particle according to any one of claims 1 to 6,
The variant in which the resin core is made of a fluorine-containing (meth) acrylic acid ester resin crosslinked with 0.1 to 5% by mass of a polyfunctional monomer with respect to the total mass of the resin core Resin particles. A method for producing deformed resin particles having a single depression,
A first step of producing resin particles by polymerizing a fluorine-containing (meth) acrylic acid ester monomer containing 0.1 to 5% by mass of a polyfunctional monomer;
A second step of polymerizing the resin particles obtained in the first step after absorbing a (meth) acrylic acid ester-based monomer containing 1 to 50% by mass of a polyfunctional monomer; A method for producing odd-shaped resin particles, comprising: It is a manufacturing method of the unusual shape resin particle according to claim 8,
The method for producing irregularly shaped resin particles, wherein the amount of the (meth) acrylic acid ester monomer absorbed in 1 part by mass of the resin particles in the second step is within the range of 2 to 125 parts by mass.   An external preparation comprising the deformed resin particles according to any one of claims 1 to 7.   A paint comprising the deformed resin particles according to any one of claims 1 to 7.   The light-diffusion member characterized by including the irregular-shaped resin particle of any one of Claims 1-7.