JP5365048B2 - Oval or acicular polymer particles and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an elliptic or needle-like polymer particle capable of enhancing an optical characteristic such as light diffusability and light convergency, a frictional characteristic such as slidability, and the like, and having a high aspect ratio. <P>SOLUTION: This elliptic or needle-like polymer particle has fine irregularity on a surface, and the aspect ratio P<SB>1</SB>satisfies P<SB>1</SB>&ge;1.8, where P<SB>1</SB>=major diameter L<SB>1</SB>/minor diameter D<SB>1</SB>is calculated based on the major diameter L<SB>1</SB>in a projection two-dimensional diagram obtained by emitting light from a direction orthogonal to an major-axial direction of the particle, and based on a minor diameter D<SB>1</SB>therein. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to elliptical or acicular polymer particles and a method for producing the same.

Particles or fillers having a micron-size high aspect ratio are used in various fields such as electronic / electrical materials, optical materials, building materials, biological / pharmaceutical materials, cosmetics and the like as fillers and specimens.
Many of the particles having a high aspect ratio that are generally used are made of an inorganic material such as a metal oxide.
Since such inorganic materials have a higher specific gravity than organic materials, they are not only difficult to disperse uniformly depending on the intended use of films, molded products, etc., but also difficult to become familiar with resins. Inconvenience may occur.

  By the way, as the development of resin particles progresses in recent years, it has a peculiar shape such as a disk shape or a flat shape, which is different from the amorphous or spherical particles obtained from the conventionally used pulverization method and solution polymerization method. Resin particles have been developed (Patent Document 1: Japanese Patent Publication No. 6-53805, Patent Document 2: JP-A-5-317688, etc.).

Since these particles are superior to conventional spherical particles in properties such as concealability, whiteness, and light diffusibility, they are used as coating materials and coating agents for paper such as information recording paper (Patent Document 3: Special). (Kaihei 2-14222), light diffusion sheet (Patent Document 4: Japanese Patent Laid-Open No. 2000-39506), and the like.
On the other hand, although all the particles are plate-like, when compared with plate-like particles made of inorganic compounds such as talc and mica, remarkable improvement in slipperiness, light condensing property, light diffusibility, etc. can still be achieved. Not.

Therefore, in order to improve these characteristics, recently, resin particles having a specific shape formed by two curved surfaces based on the boundary line have been reported (Patent Document 5: International Publication No. 01/070826 pamphlet). Improvement of slipperiness, light condensing property, light diffusibility, etc. has been studied using resin particles.
Each of these characteristics greatly depends on the size and aspect ratio of the particles, but with the method of Patent Document 5, it is difficult to produce particles with a high aspect ratio and a micron size, Further improvements are required in terms of size and shape.

  In addition, organic particles having a high aspect ratio can be produced by, for example, a mechanical method including melting, spinning, and cutting processes. In this method, however, the particle size can be reduced to a micron size. Not only is it technically difficult, but time and labor are required for mass production. Moreover, with such a mechanical method, it is difficult to obtain high-precision oval-spherical particles that have a thick central portion and become narrower toward both poles without a fracture surface.

  From these points, optical properties such as light diffusibility and light condensing properties, friction properties such as slipperiness, adhesion, adhesion, material mechanical properties such as impact strength and tensile strength of molded products, developer High aspect ratio and micron-sized oval or needle-shaped organic materials that have the potential to improve various properties such as cleaning characteristics while maintaining their chargeability, flowability, paint matteness, and hiding properties There is a need for particle development.

Japanese Patent Publication No. 6-53805 JP-A-5-317688 Japanese Patent Laid-Open No. 2-14222 JP 2000-39506 A International Publication No. 01/070826 Pamphlet JP 2007-70372 A

  The present invention has been made in view of such circumstances, and an ellipse having a high aspect ratio that can improve optical characteristics such as light diffusibility and light condensing property, and friction characteristics such as slipperiness. It is an object to provide a needle-like or needle-like polymer particle and a method for producing the same.

The inventors of the present invention have made extensive studies to achieve the above object, and have already found elliptical polymer particles having a high aspect ratio (Patent Document 6: JP 2007-70372 A).
Since these particles have a smooth surface, the specific surface area is small, and there is room for improvement in terms of light diffusibility.
Therefore, as a result of further studies, the present inventors have found that elliptical or acicular polymer particles having fine irregularities on the surface and having a high aspect ratio have optical properties such as light diffusibility and light condensing properties. The present invention was completed by finding out not only superiority but also excellent flowability and finding an efficient method for producing the particles.

That is, the present invention
1. Oval or acicular polymer particles having fine irregularities on the surface, wherein the polymer particles are styrene monomers, (meth) acrylic acid ester monomers, styrene sulfonates, styrene carboxylates, (meta ) A particle made of at least one polymer selected from acrylate, (meth) acrylate carboxylate, and (meth) acrylate sulfonate, and orthogonal to the major axis direction of the particle the aspect ratio calculated from the major axis of the projection a two-dimensional diagram obtained by irradiating light from a direction (L ₁₎ minor axis and (D ₁₎ to (P ₁₎ = major axis (L ₁₎ / short diameter (D ₁ ) is less than the (P ₁₎ ≧ 1.8, and a specific surface area of the particles, elliptical or needle-like polymer particles and satisfies the following formula (1),
(SB) / (SD) ≧ 5 (1)
(In the formula, SB means the actual specific surface area of the particles, and SD means the theoretical specific surface area of true spherical particles calculated from the average particle diameter of the particles.)
2. 1 elliptical or acicular polymer particles having a specific surface area of 10 m ² / g or more ,
3. Average length (L _1a) is 1 or 2 elliptical or acicular polymer particles is 0.01~500μm of the major axis (L _1),
4). Any one of 1-3 elliptical or acicular polymer particles that are porous ;
5. A method for producing elliptical or acicular polymer particles in which a monomer is solution polymerized in the presence of a solvent, wherein the total light transmittance of the reaction medium including the monomer is 20 to 70%, and an emulsified part, a dissolved part, 1 for producing the elliptical or acicular polymer particles , wherein the polymerization is performed under the coexisting conditions ;
6). Processes for the manufacture of said solvent, elliptical or needle-like polymer particles of 5 is a mixed solvent of water and a water-soluble organic solvent,
7). The method for producing 6 elliptical or acicular polymer particles, wherein the solvent further contains a hydrophobic organic solvent ,
8). A resin composition comprising any one of elliptical or acicular polymer particles of 1-4 ,
9. A sheet for light diffusion using any one of elliptical or acicular polymer particles of 1-4 ,
10. A cosmetic member using the elliptical or acicular polymer particles of any one of 1 to 4 ,
11. 1 to 4 colored material using the elliptical or acicular polymer particles,
12 A paint comprising any one of the elliptical or acicular polymer particles 1 to 4 is provided.

The elliptical or acicular polymer particles of the present invention have fine irregularities on the surface, a high aspect ratio of 1.8 or more, and high light diffusibility. Furthermore, by appropriately adjusting the size of the surface irregularities and the porosity, it is possible to diffuse light with a high light transmittance.
Moreover, since the main component is an organic component, not only can the refractive index of the resin be easily changed using it as a resin additive, but also the particle diameter can be reduced, so that fine packing is possible, It becomes very easy to change the light diffusivity and refractive index. Therefore, the elliptical or acicular polymer particles of the present invention can be suitably used as an additive for a light diffusion sheet.
Furthermore, for example, when used as a member of cosmetics and the like, not only conventional cosmetic effects such as hiding by light diffusibility, but also a great effect as an auxiliary to obtain smoothness etc. to improve flowability due to high aspect ratio There is.
Moreover, since it is porous, multifunctional effects such as water absorption and oil absorption can be obtained.

Furthermore, since it is an organic polymer particle and has a specific gravity smaller than that of inorganic particles, when used as an additive for various resins, it is excellent in dispersibility in the resin as an additive and affinity with the resin. Therefore, a resin molded product such as a film obtained by molding a resin composition containing the particles and various resins has excellent mechanical properties such as strength.
In addition, since the main component is an organic component, the surface of the particles can be easily subjected to an inorganic or organic coating treatment, so that a functional capsule can be produced. And since it can also be set as the particle | grains which have an ionic functional group, a multifunctional particle | grain can be produced by modifying this functional group.
Furthermore, since the main component is an organic component, it can be easily colored with pigments, dyes, etc., and can be applied to the field of coloring materials such as paints and toner materials.

Such elliptical or acicular polymer particles having a high aspect ratio are subjected to a plating process, vacuum discharge deposition, or the like, thereby providing an electromagnetic shielding filler, a conductive filler that imparts conductivity to a plastic material, etc., and a liquid crystal As conductive particles used for conductive materials such as the connection of display panel electrodes and driving LSIs, the connection of LSI chips to circuit boards, and other conductive materials for connecting electrode terminals with a very small pitch, Application is possible.
Since the elliptical or acicular polymer particles of the present invention have a high aspect ratio and can be easily made micron-sized, they can be used as fillers and specimens as electronic / electrical materials, optical materials, building materials, biological materials.・ Applicable in various fields such as pharmaceutical materials and cosmetics.

Hereinafter, the present invention will be described in more detail.
The elliptical or acicular polymer particles according to the present invention have fine irregularities on the surface, and the major axis (L ₁ ) of the projected two-dimensional view obtained by irradiating light from the direction perpendicular to the major axis direction of the particles. The aspect ratio (P ₁ ) calculated from the minor axis (D ₁ ) = major axis (L ₁ ) / minor axis (D ₁ ) satisfies (P ₁ ) ≧ 1.8.

In the present invention, the aspect ratio (P ₁ ) in the projection two-dimensional view obtained by irradiating light from the direction perpendicular to the major axis direction of the elliptical or needle-like polymer particles is (P ₁ ) ≧ 1.8. From the viewpoint of light diffusion performance and maintenance (hardness) of the shape of the elliptical or acicular polymer particles in the composition, 1.8 ≦ (P ₁ ) ≦ 20 is preferable, and 2.0 ≦ (P ₁ ) ≦ 15 is more preferable, and 2.2 ≦ (P ₁ ) ≦ 10 is optimal.
Furthermore, the shape of the elliptical or acicular polymer particles viewed from the major axis direction (that is, the same as the shape of the projected two-dimensional view obtained by irradiating light from the major axis direction) is substantially circular or has a major axis and a minor axis. An elliptical shape with a ratio to the diameter of 1 is preferable.

The elliptical or acicular polymer particles of the present invention are presumed to be constituted by agglomeration of a large number of fine particles, and thus have fine irregularities on the surface that are considered to be derived from the fine particles. Moreover, since it has such a structure, it has porosity and a specific surface area is comparatively large.
The specific surface area of the elliptical or acicular polymer particles of the present invention is not particularly limited, but it is preferable to satisfy the following formula (1) in consideration of further increasing the light diffusibility.
(SB) / (SD) ≧ 5 (1)
(In the formula, SB means the actual specific surface area of the elliptical or acicular polymer particles, and SD means the theoretical specific surface area of the true spherical particles calculated from the average particle diameter of the elliptical or acicular polymer particles.)
More preferably, (SB) / (SD) ≧ 10, and still more preferably (SB) / (SD) ≧ 15.

Further, the specific surface area of the elliptical or acicular polymer particle itself of the present invention is not particularly limited, but is preferably 10 m ² / g or more in consideration of further increasing the light diffusibility as described above. 15 m ² / g or more is more preferable.
The specific surface area is a value measured by a gas adsorption method using an automatic specific surface area pore distribution measuring apparatus (TriStar 3000, manufactured by Shimadzu Corporation).

Furthermore, the average major axis (L _1a ) of the major axis (L ₁ ) in the projected two-dimensional view obtained by irradiating light from the direction orthogonal to the major axis direction of the elliptical or acicular polymer particles of the present invention is 0.01 -500 micrometers is preferable, 0.1-200 micrometers is more preferable, 0.3-100 micrometers is still more preferable, 0.8-80 micrometers is further more preferable, and 1-50 micrometers is optimal.
Although particles having an average major axis (L _1a ) exceeding 500 μm can be produced, there are few merits, especially in the cosmetics field and the electric material field requiring diffusion performance. On the other hand, when the average major axis (L _1a ) is less than 0.01 μm, the particle diameter is too small, so that it is difficult to form elliptical or acicular polymer particles with the fine particles of the present invention, and the particles aggregate. There is a high possibility that monodispersed particles cannot be obtained.

The molecular weight of the polymer constituting the elliptical or acicular polymer particles of the present invention is not particularly limited, and is usually about 1,000 to 3,000,000 in weight average molecular weight. The weight average molecular weight is a value measured by gel permeation chromatography.
In addition, when the resin composition containing the elliptical or acicular polymer particles of the present invention is molded into a diffusion plate or a diffusion sheet, the elliptical or acicular polymer is used in order to exhibit sufficient heat resistance even at high temperatures. The melting point of the particles is preferably 60 ° C. or higher.
The elliptical or acicular polymer particles of the present invention can be improved in melting point by polymerization using a monomer that improves heat resistance. For example, by introducing an ionic functional group into the monomer or changing the type or amount thereof, the temperature can be 100 ° C. or higher, in some cases 120 ° C. or higher, and even 150 ° C. or higher. .
The melting point in the present invention means a temperature at which a peak due to melting is observed in a differential scanning calorimeter (DSC6200, manufactured by Seiko Instruments Inc.).

The elliptical or acicular polymer particles of the present invention have a state in which the reaction medium including the monomer has both dissolved and dispersed portions when the monomer is solution-polymerized in the presence of a solvent. That is, it can be produced by at least having both an emulsified part and a dissolved part (fuzzy).
In this case, when the emulsion is completely emulsified, it is stably present as fine particles, so that an oval or needle-like aggregate of fine particles is difficult to form and becomes only fine particles. Even in the case of an elliptical shape or a needle shape, since the fine particles are too small, they cannot be composed of fine particles when forming the elliptical particles, so that particles having fine irregularities on the target surface are obtained. I can't.
On the other hand, when completely dissolved, it is difficult to synthesize elliptical or acicular particles. In addition, even when the shape is an ellipse or a needle, it is difficult to form an aggregate of fine particles.

The total light transmittance of the reaction medium can be used as a standard for creating the coexistence state of the emulsified part and the dissolved part as described above. Here, the total light transmittance is a value measured by putting a solution into a cell having a cell thickness of 1 cm using a haze meter produced based on JIS K7136, 7361.
In producing the elliptical or acicular polymer particles of the present invention, it is preferable to adjust the total light transmittance of the reaction medium including the monomer to 20 to 70%, more preferably 25 to 70%, More preferably, it is adjusted to 25 to 65%, and best to 30 to 60%.
This total light transmittance can be appropriately adjusted by changing the types and amount ratios of the monomer and the solvent, which will be described in detail later, and the amount ratios of dispersants and emulsifiers used as necessary.

The organic monomer that can be used for the production of the elliptical or acicular polymer particles of the present invention is not particularly limited, and a monomer having an unsaturated double bond as generally used in solution polymerization is used. Can be mentioned.
Specific examples thereof include (i) styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, pt-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-phenyl Styrene monomers such as styrene, p-chlorostyrene, 3,4-dichlorostyrene, (ii) methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, hexyl acrylate, acrylic 2-ethylhexyl acid, n-octyl acrylate, dodecyl acrylate, lauric acrylate , Stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, propyl methacrylate, hexyl methacrylate, methacryl (Meth) acrylic acid ester monomers such as 2-ethylhexyl acid, n-octyl methacrylate, dodecyl methacrylate, lauryl methacrylate, stearyl methacrylate, (iii) vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, etc. (Iv) (meth) acrylic acid derivatives such as acrylonitrile and methacrylonitrile, (v) vinyl esters such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether. Ter monomers, (vi) vinyl ketone monomers such as vinyl methyl ketone, vinyl hexyl ketone, methyl isopropenyl ketone, (vii) N such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone -Vinyl compounds, (viii) vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, or (meth) acrylic acid ester monomers having a fluorine alkyl group such as trifluoroethyl acrylate, tetrafluoropropyl acrylate, etc. , (Ix) styrene sulfonic acids such as styrene sulfonic acid and α-methyl styrene sulfonic acid and salts thereof, (x) styrene carboxylic acids such as vinyl benzoic acid and salts thereof, (xi) (meth) acrylic acid and the like (Meta Acrylic acid and its salts, (xii) maleic acid or maleic acid mono C1-8 alkyl esters, itaconic acid or itaconic acid mono C1-8 alkyl esters and the like (meth) acrylic acid ester carboxylic acids and salts thereof, (xiii) C1-10 alkyl (meth) allylsulfosuccinic acid ester, sulfo C2-6 alkyl (meth) acrylate such as sulfopropyl (meth) acrylate, methyl vinyl sulfonate, 2-hydroxy-3- (meth) acryloxypropyl sulfonic acid , 2- (meth) acryloylamino-2,2-dimethylethanesulfonic acid, 3- (meth) acryloyloxyethanesulfonic acid, 3- (meth) acryloyloxy-2-hydroxypropanesulfonic acid, 2- (meth) acrylamide 2-Methylpropa (Meth) acrylic acid ester sulfones such as sulfonic acid, 3- (meth) acrylamide-2-hydroxypropanesulfonic acid, 2-sulfoethyl methacrylate, decaneallyl succinate sulfonic acid, bis (orioxyethylene diphenyl ether) methacrylate sulfonic acid Examples include acids and salts thereof.
Depending on the polymerizable group, a monomer having a reactive functional group such as a hydroxyl group, an amino group, an epoxy group, a thiol group, an isocyanate group, an oxazoline group, or a carbodiimide group can also be used.
In addition, these organic monomers can be used individually by 1 type or in combination of 2 or more types.

In the present invention, when only a monomer having no hydrophilic group is used, it is likely to be in an emulsified state or a suspended state, and it is difficult to create a (fuzzy) state having both the emulsified part and the dissolved part.
For this reason, it is preferable to use a monomer having a hydrophilic group alone or in combination with a hydrophobic monomer.
Examples of the hydrophilic group include an ester group, an ether group, an ethylene oxide group, a hydroxyl group, and an ionic functional group. Among these, an ionic functional group is preferable.

The ionic functional group may be either an anionic functional group or a cationic functional group. Examples of the anionic functional group include a carboxyl group, a sulfonic acid group, a phosphoric acid group, a phenolic hydroxyl group, and salts thereof. Examples of cationic functional groups include amino groups, imidazole groups, pyridine groups, amidino groups, and salts thereof.
In particular, since there are many general-purpose products, there are many types, and the size and shape of elliptical or acicular polymer particles can be controlled efficiently, an anionic functional group is suitable and easy introduction into the molecule. In addition, since it is excellent in stability and safety, among these, one or more functional groups selected from a carboxyl group, a sulfonic acid group, a phosphoric acid group, and derivatives thereof are preferable.

Examples of compounds that can be counterions of these ionic functional groups include metal cations, ammonium cations, pyridinium cations, and phosphonium cations for anionic functional groups, and chlorides for cationic functional groups. Examples thereof include halide ions such as bromide and iodide.
In the case of using an anionic functional group, a metal cation is particularly preferable as a counter ion in consideration of production cost and abundant types and efficient control of the accuracy, size, shape, etc. of elliptical or acicular polymer particles. It is.

  Metal cations include alkali metal cations such as lithium, sodium, rubidium and cesium, alkaline earth metal cations such as magnesium, calcium, strontium and barium, other non-transition metal cations such as aluminum, zinc, copper, manganese and nickel , Transition metal-containing cations such as oxides, hydroxides and carbonates of transition metals such as cobalt, iron and chromium.

Examples of the monomer having an anionic functional group include a monocarboxylic acid monomer, a dicarboxylic acid monomer, a sulfonic acid monomer, a sulfate ester monomer, a phenolic hydroxyl group-containing monomer, and a phosphoric acid monomer.
Examples of the monocarboxylic acid monomer include (meth) acrylic acid, crotonic acid, cinnamic acid, maleic acid mono C1-8 alkyl ester, itaconic acid mono C1-8 alkyl ester, vinyl benzoic acid, and salts thereof. .
Examples of the dicarboxylic acid monomer include (anhydrous) maleic acid, α-methyl (anhydride) maleic acid, α-phenyl (anhydride) maleic acid, fumaric acid, itaconic acid, and salts thereof.

  Examples of the sulfonic acid monomer include alkene sulfonic acid such as ethylene sulfonic acid, vinyl sulfonic acid, (meth) allyl sulfonic acid, aromatic (styrene) sulfonic acid such as styrene sulfonic acid, α-methylstyrene sulfonic acid, C1 10 alkyl (meth) allyl sulfosuccinic acid ester, sulfo C2-6 alkyl (meth) acrylate such as sulfopropyl (meth) acrylate, methyl vinyl sulfonate, 2-hydroxy-3- (meth) acryloxypropyl sulfonic acid, 2 -(Meth) acryloylamino-2,2-dimethylethanesulfonic acid, 3- (meth) acryloyloxyethanesulfonic acid, 3- (meth) acryloyloxy-2-hydroxypropanesulfonic acid, 2- (meth) acrylamide-2 -Methylpropanesulfonic acid, 3 (Meth) a sulfonic acid group-containing unsaturated esters and their salts, such as acrylamido-2-hydroxypropane sulfonic acid.

Examples of the sulfate ester-based monomers include (meth) acryloyl polyoxyalkylene (degree of polymerization: 2 to 15) sulfate such as polyoxypropylene monomethacrylate sulfate ester and salts thereof.
Examples of the phenolic hydroxyl group-containing monomer include hydroxystyrene, bisphenol A monoallyl ether, bisphenol A mono (meth) acrylic ester, and salts thereof.
Examples of phosphoric acid monomers include (meth) acrylic acid hydroxyalkyl phosphate monoesters such as 2-hydroxyethyl (meth) acryloyl phosphate and phenyl-2-acryloyloxyethyl phosphate, and vinyl phosphate.

  In this case, examples of the salt include alkali metal salts such as sodium salt and potassium salt, amine salts such as triethanolamine, and quaternary ammonium salts such as tetra C4-18 alkyl ammonium salt.

On the other hand, the monomer having a cationic functional group includes a primary amino group-containing monomer, a secondary amino group-containing monomer, a tertiary amino group-containing monomer, a quaternary ammonium base-containing monomer, a heterocyclic ring-containing monomer, and a phosphonium group-containing monomer. , Sulfonium group-containing monomers, sulfonic acid group-containing polymerizable unsaturated monomers, and the like.
Examples of the primary amino group-containing monomer include C3-6 alkenylamines such as (meth) allylamine and crotylamine, amino C2-6 alkyl (meth) acrylates such as aminoethyl (meth) acrylate, vinylaniline, and p-aminostyrene. A monomer having an aromatic ring and a primary amino group, ethylenediamine, polyalkylenepolyamine and the like can be mentioned.
Examples of secondary amino group-containing monomers include C1-6 alkylamino C2-6 alkyl (meth) acrylates such as t-butylaminoethyl (meth) acrylate and methylaminoethyl (meth) acrylate, and C6 such as di (meth) allylamine. ˜12 dialkenylamine, ethyleneimine, diallylamine and the like.

  Tertiary amino group-containing monomers include N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminopropyl Di-C1-4 alkylamino C2- such as (meth) acrylate, N, N-dibutylaminoethyl (meth) acrylate, Nt-butylaminoethyl (meth) acrylate, N, N-dimethylaminobutyl (meth) acrylate, etc. DiC1-4 alkylamino C2-6 alkyl (meth) acrylamide, N, N such as 6 alkyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, etc. -An aromatic ring such as dimethylaminostyrene and 3 Such a monomer having an amino group.

Examples of the quaternary ammonium base-containing monomer include those obtained by quaternizing a tertiary amine using a quaternizing agent such as C1-12 alkyl chloride, dialkyl sulfuric acid, dialkyl carbonate, benzyl chloride or the like.
For example, 2- (meth) acryloyloxyethyltrimethylammonium chloride, 2- (meth) acryloyloxyethyltrimethylammonium bromide, (meth) acryloyloxyethyltriethylammonium chloride, (meth) acryloyloxyethyldimethylbenzylammonium chloride, (meth) Alkyl (meth) acrylate quaternary ammonium salts such as acryloyloxyethyl methylmorpholino ammonium chloride, (meth) acryloylaminoethyltrimethylammonium chloride, (meth) acryloylaminoethyltrimethylammonium bromide, (meth) acryloylaminoethyltriethylammonium chloride , (Meth) acryloylaminoethyldimethylbenzylammoni Alkyl (meth) acrylamide quaternary ammonium salts such as muchloride, dimethyldiallylammonium methylsulfate, trimethylvinylphenylammonium chloride, tetrabutylammonium (meth) acrylate, trimethylbenzylammonium (meth) acrylate, 2- (methacryloyloxy) ethyl Other quaternary ammonium base-containing monomers such as trimethylammonium dimethyl phosphate are listed.

Heterocycle-containing monomers include N-vinylcarbazole, N-vinylimidazole, N-vinyl-2,3-dimethylimidazoline, N-methyl-2-vinylimidazoline, 2-vinylpyridine, 4-vinylpyridine, N-methyl Examples include vinyl pyridine and oxyethyl-1-methylene pyridine.
Examples of the phosphonium group-containing monomer include glycidyl tributyl phosphone.
Examples of the sulfonium group-containing monomer include 2-acryloxyethyldimethylsulfone, glycidylmethylsulfonium, and the like.
Examples of the sulfonic acid group-containing polymerizable unsaturated monomer include (meth) acrylamide-alkanesulfonic acid such as 2-acrylamido-2-methylpropanesulfonic acid, and sulfoalkyl (meth) acrylate such as 2-sulfoethyl (meth) acrylate. Can be mentioned.
The monomer having a cationic functional group can also be used as an inorganic acid salt such as hydrochloride or phosphate, or an organic acid salt such as formate or acetate.
In the above description, “C” means carbon number.

In particular, in the present invention, a water-soluble monomer is preferable. By using a water-soluble monomer, the particle diameter of the obtained elliptical or acicular polymer particles can be further reduced.
Specific examples of the water-soluble monomer include (meth) acrylic acid, ethylene sulfonic acid, vinyl sulfonic acid, (meth) allyl sulfonic acid, styrene sulfonic acid, α-methyl styrene sulfonic acid, 2-hydroxy-3- (meth). Acryloxypropylsulfonic acid, 2- (meth) acryloylamino-2,2-dimethylethanesulfonic acid, 3- (meth) acryloyloxyethanesulfonic acid, 3- (meth) acryloyloxy-2-hydroxypropanesulfonic acid, 2 -(Meth) acrylamido-2-methylpropanesulfonic acid, 3- (meth) acrylamide-2-hydroxypropanesulfonic acid and salts thereof; (meth) acryloyl polyoxyalkylene (polymerization) such as polyoxypropylene monomethacrylate sulfate compound Degree 2-15) Sulfate 2-hydroxyethyl (meth) acryloyl phosphate; acrylamide, ethylenediamine, N, N-dimethylaminoethyl (meth) acrylate; 2- (meth) acryloyloxyethyltrimethylammonium chloride, 2- (meth) acryloyl Quaternary ammonium base-containing monomers such as oxyethyltrimethylammonium bromide, (meth) acryloyloxyethyltriethylammonium chloride, (meth) acryloylaminoethyltrimethylammonium chloride; 2-vinylpyridine, 4-vinylpyridine, 2-acrylamide-2 -Methylpropane sulfonic acid etc. are mentioned.

Among these, (meth) acrylic acid, ethylenesulfonic acid, vinylsulfonic acid, (meth) allylsulfonic acid, styrenesulfonic acid, α-methylstyrenesulfonic acid, 2-hydroxy-3- (meth) acryloxypropylsulfonic acid 2- (meth) acryloylamino-2,2-dimethylethanesulfonic acid, 3- (meth) acryloyloxyethanesulfonic acid, 3- (meth) acryloyloxy-2-hydroxypropanesulfonic acid and salts thereof; polyoxy (Meth) acryloyl polyoxyalkylene (polymerization degree: 2 to 15) sulfate such as propylene monomethacrylate sulfate compound and salts thereof are more preferable.
In addition, the monomer which has an anionic functional group demonstrated above and the monomer which has a cationic functional group can be used individually by 1 type or in combination of 2 or more types, respectively.

In the present invention, it is particularly preferable to copolymerize the above-mentioned monomer having a hydrophilic group and a hydrophobic monomer. By doing so, it becomes possible to increase the aspect ratio as well as control the fine particle diameter and the porosity of the obtained elliptical or acicular polymer particles, and to approximate the ideal elliptical shape.
Here, as a hydrophobic monomer, a styrene-type monomer, a (meth) acrylic acid ester-type monomer, etc. are preferable. These hydrophobic monomers can be used singly or in combination of two or more.

In particular, a combination of at least one selected from the following water-soluble monomer α group and at least one selected from the hydrophobic monomer β group can be suitably employed.
(1) Water-soluble monomer α group Styrene sulfonic acid and its salt, styrene carboxylic acid and its salt, (meth) acrylic acid and its salt, (meth) acrylic ester carboxylic acid and its salt, (meth) acrylic Acid ester sulfonic acid and its salt, vinyl sulfonic acid and its salt, vinyl carboxylic acid and its salt, (meth) acrylic sulfonic acid and its salt, (meth) acrylic carboxylic acid and its salt (2) hydrophobic Monomer β group Styrene monomer, (meth) acrylic acid ester monomer

  In this case, the use ratio of the water-soluble monomer and the hydrophobic monomer is not particularly limited, and can be, for example, water-soluble monomer: hydrophobic monomer = 5: 95 to 50:50 by mass ratio. . Considering that the aspect ratio of the particles to be obtained is further increased and approaches an ideal elliptical shape, the use ratio thereof is preferably water-soluble monomer: hydrophobic monomer = 10: 90 to 40:60, 15:85 ~ 25: 75 is more preferred.

In addition, the total content of organic monomers in the reaction solution (hereinafter referred to as polymerization component content) increases the aspect ratio of the resulting particles, and efficiently produces ideal elliptical particles. The total reaction solution is preferably 1 to 80% by mass, more preferably 5 to 50% by mass, and still more preferably 10 to 30% by mass.
That is, when the content of the polymerization component exceeds 80% by mass, the component becomes excessive, and the balance in the solution is easily lost to form spherical particles. As a result, the surface of the present invention has fine irregularities (small It may be difficult to obtain monodispersed elliptical or acicular polymer particles. On the other hand, when the amount is less than 1% by mass, particles having a desired shape can be obtained, but it takes a long time to complete the reaction, which is not practical.

As the solvent used for the polymerization reaction, a solvent that can obtain at least both the emulsified part and the dissolved part (fuzzy) state in the reaction medium including the above-described monomer may be used. It is preferable to use a mixed solvent composed of water and a water-soluble organic solvent.
In addition, when using hydrophobic monomers, in addition to water and water-soluble organic solvents, in order to maintain harmony of mixing, it is easy to obtain both the desired emulsified and dissolved (fuzzy) states. Furthermore, it is preferable to use a hydrophobic organic solvent in combination.
Here, the hydrophobic organic solvent means a solvent in which the mixed liquid cannot maintain a uniform appearance after gently mixing with pure water of the same volume at a temperature of 20 ° C. at 1 atmosphere and the flow is stopped. An organic solvent means that the liquid mixture maintains a uniform appearance.

  Specific examples of the water-soluble organic solvent include methanol, ethanol, 2-propanol, ethylene glycol, propylene glycol, methyl cellosolve, ethyl cellosolve, propyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, methyl carbitol, ethyl carbitol, and butyl. Examples thereof include carbitol, ethyl carbitol acetate, acetone, tetrahydrofuran, dimethylformamide, N-methyl-2-pyrrolidone, and acetonitrile. These solvents can be used alone or in combination of two or more.

  Specific examples of the hydrophobic organic solvent include 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, and isopentyl. Alcohol, tert-pentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 4-methyl-2-pentanol, 2-ethylbutanol, 1-heptanol, 2-heptanol, 3-heptanol, 2-octanol, Higher alcohols such as 2-ethyl-1-hexanol, benzyl alcohol and cyclohexanol; ether alcohols such as butyl cellosolve; ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ethyl acetate, butyl acetate, ethyl propionate, butyl Esters such as rubitol acetate; pentane, 2-methylbutane, n-hexane, cyclohexane, 2-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane, heptane, n-octane, isooctane, 2,2 , 3-trimethylpentane, decane, nonane, cyclopentane, methylcyclopentane, methylcyclohexane, ethylcyclohexane, p-menthane, dicyclohexyl, benzene, toluene, xylene, ethylbenzene and other aliphatic or aromatic hydrocarbons; carbon tetrachloride , Halogenated hydrocarbons such as trichloroethylene, chlorobenzene, and tetrabromoethane. These can be used alone or in combination of two or more.

Among these, the hydrophobic organic solvent that can be easily adjusted to the above-described fuzzy state is compatible with a water-soluble organic solvent and has a solubility in water of less than 10 g / 100 g of water.
Examples of such hydrophobic organic solvents include 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, and isopentyl. Alcohols such as alcohol, tert-pentyl alcohol, 1-hexanol; pentane, 2-methylbutane, n-hexane, cyclohexane, 2-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane, heptane, n- Aliphatic or aromatic such as octane, isooctane, 2,2,3-trimethylpentane, decane, nonane, cyclopentane, methylcyclopentane, methylcyclohexane, ethylcyclohexane, p-menthane, dicyclohexyl, benzene, toluene, xylene, ethylbenzene Hydrocarbon such systems; methyl ethyl ketone, and diisobutyl ketone; the like ester solvents such as ethyl acetate and the like, in particular, 1-butanol is preferred.

The mixing ratio of the solvent is arbitrary. For example, the mass ratio of water: organic solvent other than water = 1: 99 to 99: 1 can be obtained, but the intended fuzzy state can be easily obtained. Therefore, in order to improve (co) polymerization and obtain particles having a smaller particle diameter and a high aspect ratio more efficiently, 10:90 to 80:20, particularly 30:70 to 70:30. It is preferable that
When a mixed solvent of a hydrophilic organic solvent and a hydrophobic organic solvent is used as the organic solvent other than water, the hydrophilic organic solvent: hydrophobic organic solvent = 10: 90 in mass ratio for the same reason as described above. It is preferable to set it as the range of -90: 10, it is more preferable to set it as the range of 80: 20-20: 80, and the range of 70: 30-30: 70 is the best.

In the present invention, by adjusting the solvent composition as described above, the particle diameter and aspect ratio of the elliptical or acicular polymer particles can be controlled, and the size of the fine irregularities on the surface, which is a major feature of the present invention. In other words, it is possible to adjust the particle diameter of the microparticles that are assumed to constitute elliptical or acicular polymer particles, and as a result, the porosity can be controlled, so that the optical characteristics, water absorption and absorption can be controlled. Thus, various properties such as oil absorbency can be controlled in a well-balanced manner.
In the present invention, it is not clear why the oval or acicular polymer particles having fine irregularities on the surface (presumed to be formed from an aggregate of fine particles) are formed, but in the reaction medium Due to the presence of the emulsifying part and the dissolving part, emulsion polymerization and dispersion polymerization proceed with each other, and at the same time, the surface tension changes due to the influence of stirring and polar groups (hydrophilic groups) that may be present in the monomer. It is presumed to be caused by

  As the polymerization initiator used in carrying out the polymerization reaction, various known polymerization initiators can be used. For example, benzoyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, sodium persulfate, Peroxides such as ammonium sulfate, azobisisobutyronitrile, azobismethylbutyronitrile, azobisisovaleronitrile, 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis (N , N'-dimethyleneisobutylamidine) dihydrochloride, azo compounds such as 2,2'-azobis-2-cyanopropane-1-sulfonic acid disodium salt, various oil-soluble, water-soluble, and ionic polymerization initiations Agents. These polymerization initiators can be used alone or in combination of two or more.

The reaction temperature at the time of polymerization varies depending on the type of solvent to be used and cannot be generally defined, but is usually about -100 to 200 ° C, preferably 0 to 150 ° C, more preferably 40 to 100. ° C.
In addition, the reaction time is not particularly limited as long as it is a time required for the oval or needle-like formation of the particles to be almost completed, and the monomer species and the amount thereof, the type of ionic functional group, the viscosity of the solution Although it greatly depends on the concentration and the like, considering that the target elliptical or acicular particles are ideally shaped and efficiently manufactured, for example, in the case of 40 to 100 ° C., 2 to 2 24 hours, preferably about 8 to 16 hours.

In the production of elliptical or acicular polymer particles, a (polymer) dispersant, a stabilizer, an emulsifier (surfactant), etc. are added in an amount of 0.01 to It can also be blended in an appropriate amount of 50% by mass.
Examples of the dispersant and stabilizer include polyhydroxystyrene, polystyrene sulfonic acid, vinylphenol- (meth) acrylic acid ester copolymer, styrene- (meth) acrylic acid ester copolymer, styrene-vinylphenol- (meth) acrylic. Polystyrene derivatives such as acid ester copolymers; poly (meth) acrylic ester copolymers, poly (meth) acrylic acid, poly (meth) acrylamide, polyacrylonitrile, polyethyl (meth) acrylate, polybutyl (meth) acrylate, etc. Poly (meth) acrylic acid derivatives; polyvinyl alkyl ether derivatives such as polymethyl vinyl ether, polyethyl vinyl ether, polybutyl vinyl ether, polyisobutyl vinyl ether; polyethylene glycol, polypropylene glycol, etc. Polyalkylene glycol derivatives; cellulose derivatives such as cellulose, methyl cellulose, cellulose acetate, cellulose nitrate, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose; polyvinyl acetate derivatives such as polyvinyl alcohol, polyvinyl butyral, polyvinyl formal, and polyvinyl acetate Nitrogen-containing polymer derivatives such as polyvinyl pyridine, polyvinyl pyrrolidone, polyethyleneimine, poly-2-methyl-2-oxazoline; Polyhalogenated vinyl derivatives such as polyvinyl chloride and polyvinylidene chloride; Polysiloxane derivatives such as polydimethylsiloxane And various hydrophobic or hydrophilic dispersants and stabilizers. These can be used alone or in combination of two or more.

  Examples of emulsifiers (surfactants) include alkyl sulfate salts such as sodium lauryl sulfate, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, alkylnaphthalene sulfonates, fatty acid salts, alkyl phosphates, and alkylsulfosuccinates. Anionic emulsifiers; cationic amines such as alkylamine salts, quaternary ammonium salts, alkylbetaines, amine oxides; polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene alkyl phenyl ethers, sorbitan fatty acid esters, Nonionic emulsifiers such as glycerin fatty acid ester and polyoxyethylene fatty acid ester are listed. These can be used alone or in combination of two or more.

The dispersant, stabilizer and emulsifier are appropriately selected according to the reaction solvent, but in the present invention, it is preferable to use a mixed solvent of water and a water-soluble organic solvent as the reaction solvent. Therefore, from the viewpoint of stabilizing the particle diameter of the resulting elliptical or acicular polymer particles and efficiently obtaining particles having a smaller particle diameter, it is preferable that these dispersants dissolve in a mixed solvent. Examples of such dispersants and stabilizers include polystyrene derivatives, poly (meth) acrylic acid derivatives, polyvinyl alkyl ether derivatives, polyalkylene glycol derivatives, polyvinyl pyrrolidone, etc., and emulsifiers such as alkyl sulfates such as sodium lauryl sulfate. Examples thereof include salts, alkylbenzenesulfonates such as sodium dodecylbenzenesulfonate, alkylnaphthalenesulfonates, and nonionic emulsifiers.
These dispersants, stabilizers, and emulsifiers are similar to the intended particles for the purpose of efficiently controlling the size, shape, etc. of the elliptical or acicular polymer particles, and from the viewpoint of the quality of the remaining components. It may be a derivative.

In the present invention, in the polymerization reaction, a crosslinking agent can be blended in an appropriate amount of 0.01 to 80% by mass with respect to the total mass of the polymerization components, depending on the intended use of the particles obtained.
Cross-linking agents include aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; ethylene glycol diacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, trimethylol Propane triacrylate, trimethylolpropane trimethacrylate, 1,4-butanediol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol dimethacrylate, penta Erythritol tetramethacrylate, glycerol acryloxy dimethacrylate DOO, N, N-divinyl aniline, divinyl ether, divinyl sulfide, compounds such as divinyl sulfone, for example. These can be used alone or in combination of two or more.

In the polymerization reaction, a catalyst (reaction accelerator) can be blended depending on the intended use of the particles obtained. The blending amount can be an appropriate amount that does not adversely affect the particle physical properties, for example, 0.01 to 20% by mass relative to the total mass of the polymerization components.
The catalyst is not particularly limited as long as it is a positive catalyst, and can be appropriately selected from known ones. Specific examples include tertiary amines such as benzyldimethylamine, triethylamine, tributylamine, pyridine and triphenylamine; quaternary ammonium compounds such as triethylbenzylammonium chloride and tetramethylammonium chloride; triphenylphosphine, tricyclo Phosphines such as phosphine; Phosphonium compounds such as benzyltrimethylphosphonium chloride; Imidazole compounds such as 2-methylimidazole and 2-methyl-4-ethylimidazole; Alkali metals such as potassium hydroxide, sodium hydroxide and lithium hydroxide Hydroxides; alkali metal carbonates such as sodium carbonate and lithium carbonate; alkali metal salts of organic acids; Lewis acidity such as boron trichloride, boron trifluoride, tin tetrachloride and titanium tetrachloride Include catalysts such as halides or complex salts. These can be used alone or in combination of two or more.

In addition, it can be dissolved in water or other polar solvents for the purpose of adjusting the size, shape, quality, etc. of the resulting elliptical or acicular polymer particles during the polymerization reaction, and is ionized into cations and anions. It is also possible to add a compound whose solution exhibits electrical conductivity.
Specific examples include salts, inorganic acids, inorganic bases, organic acids, organic bases, ionic liquids and the like. The blending amount can be an appropriate amount that does not adversely affect the physical properties of the particles, for example, 0.01 to 80% by mass relative to the total mass of the polymerization components.

Since the production method of the present invention described above is a method of controlling the particle size called solution polymerization, it is possible to precisely design the shape, particle size, etc., and as a result, the surface has fine irregularities (small Presumed to be formed from an aggregate of particles), elliptical or acicular polymer particles having a predetermined aspect ratio will be obtained.
When this production method is used, other organic compounds and the like can be directly bonded to the obtained elliptical or acicular polymer particles, so that the core / shell type structured particles are continuously and efficiently used. You can also get

When the production method of the present invention is carried out, not all of the obtained particles have the target elliptical shape or needle shape, but usually 100 obtained elliptical or needle-like polymer particles are randomly extracted. In this case, the aspect ratio (P ₁ ) = major axis calculated from the major axis (L ₁ ) and minor axis (D ₁ ) of the projected two-dimensional drawing obtained by irradiating light from the direction orthogonal to the major axis direction of each particle. The average (P _1a ) of (L ₁ ) / minor axis (D ₁ ) satisfies (P _1a ) ≧ 1.5. From a practical standpoint, this average aspect ratio is preferably (P _1a ) ≧ 1.8, more preferably 1.8 ≦ (P _1a ) ≦ 20, and even more preferably 2.0 ≦ ( P _1a ) ≦ 15, more preferably 2.2 ≦ (P _1a ) ≦ 10.

In the present invention, using a scanning electron microscope (S-4800, manufactured by Hitachi High-Technologies Corporation), a photograph is taken at a measurable magnification (300 to 100,000 times), and the obtained elliptical spherical particles are two. In a dimensioned state (usually, the elliptical spherical particles keep the major axis direction horizontal), the major axis (L ₁ ) and minor axis (D ₁ ) of each particle are measured, and the aspect ratio (P ₁ ) Is calculated.
Similarly, the average major axis (L _1a ) of the particles can be determined by repeatedly measuring the major axis (L ₁ ) at n = 100.

The elliptical or acicular polymer particles of the present invention can be further combined with other fine particles physically and chemically to form composite particles.
Specifically, (1) particles are taken in at the time of particle production, (2) addition is performed using the polarity of the ionic functional group present on the particle surface after particle production, (3) addition polymerization, polycondensation, addition The method of adding by chemical bonds, such as condensation, is mentioned.

Here, the other fine particles are not limited to organic and inorganic substances as long as the particles are smaller than the elliptical or acicular polymer particles serving as mother particles. The preferred particle size is usually about 0.01 to 1000 μm, although it depends on the size of the elliptical or acicular polymer particles.
Examples of the organic particles include particles made of a polymerizable monomer used for producing the particles of the present invention, curable particles, and organic pigments.
Inorganic particles include copper powder, iron powder, gold powder, aluminum oxide, titanium oxide, zinc oxide, silicon oxide, tin oxide, copper oxide, iron oxide, magnesium oxide, manganese oxide, calcium carbonate, magnesium hydroxide, aluminum hydroxide And inorganic particles such as metals, metal oxides, hydrated metal oxides, and inorganic pigments.
In addition, these fine particles may use a commercial item as it is, and may use what was surface-modified with surface treatment agents, such as a coupling agent, beforehand.

In particular, when the elliptical or acicular polymer particles of the present invention are used for optical applications, metal oxide fine particles having a particle diameter of 0.01 to 500 μm, particularly oxidized particles are used for the purpose of controlling the refractive index and improving light diffusibility. It is preferable to add titanium, zinc oxide, silicon oxide or the like. These can be used alone or in combination of two or more.
The addition of the metal oxide fine particles is an elliptical or acicular polymer obtained by reacting the fine particles in an amount of 0.1 to 50% by mass with respect to the entire polymerization component during the production of the particles of the present invention. For example, the fine particles can be incorporated into the particles by physical or chemical adsorption.

As already described, the elliptical or acicular polymer particles of the present invention are excellent in light diffusibility, and can be suitably used as an additive for a light diffusion sheet. Specifically, for example, a composition comprising the elliptical or needle-like polymer particles of the present invention, a binder, and other additives is coated on a transparent or milky white substrate such as a film, sheet, or plate. By forming a light diffusion layer, it can be suitably used as a light diffusion sheet used for liquid crystal displays, overhead projectors, advertising signboards, televisions, movie screens, and other video screens.
In addition to the light diffusing performance, the elliptical or acicular polymer particles of the present invention also have a porous property, a water absorbing property, an oil absorbing property, etc., and therefore can be suitably used as a functional cosmetic member. it can.

EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated more concretely, this invention is not limited to the following Example.
First, a method for measuring physical properties and the like in this example will be described.

(1) Aspect ratio of elliptical or acicular polymer particles Using a scanning electron microscope (S-4800, manufactured by Hitachi High-Technologies Corporation, hereinafter referred to as SEM) at a measurable magnification (300 to 100,000 times) Take a picture and make the resulting elliptical or acicular polymer particles two-dimensional (normally, the elliptical or acicular polymer particles keep their major axis horizontal) The major axis (L ₁ ) and minor axis (D ₁ ) are measured, and the aspect ratio (P ₁ ) is calculated.
Similarly, the average long diameter (L _1a ) of the particles is calculated by repeatedly measuring the long diameter (L ₁ ) at n = 100.

(2) The volume average particle diameter converted into a spherical shape of elliptical or acicular polymer particles was measured using MICROTRACK HRA9320-X100 (manufactured by Nikkiso Co., Ltd.).
(3) Glass transition temperature Tg
Measurement was performed using a differential scanning calorimeter (DSC6200, manufactured by Seiko Instruments Inc.).
Specifically, 10 mg of a measurement sample is precisely weighed, the precisely measured measurement sample is put in an aluminum pan, and an empty aluminum pan is used as a reference, and the temperature is raised in a measurement temperature range of 20 to 200 ° C. at normal temperature and humidity. The temperature was raised at a rate of 10 ° C./min. The endothermic (melting) peak point of the obtained reversing heat flow curve was calculated.

(4) Measurement of specific surface area It measured by the gas adsorption method using the automatic specific surface area pore distribution measuring apparatus (TriStar 3000, Shimadzu Corp. make).
(5) Measurement of specific gravity It measured using the dry-type automatic densimeter (Acpic 1330-01, Shimadzu Corp. make).

(6) Calculation of theoretical specific surface area SD (m ² / g) of true spherical particles having the same average particle diameter of elliptical or needle-like polymer particles First, the same average particle diameter of elliptical or needle-like particles is 2r (m). The radius was r (m) and the specific gravity was G (g / m ³ ). At this time, the area S ′ (m ² ) and the volume V (m ³ ) of the true spherical particles having the radius r (m) are represented by the following equations, respectively.
Area S ′ (m ² ) = 4πr ² of true spherical particles with radius r (m)
The volume of the spherical particles of radius ^{r (m) V (m 3} ) = 4πr 3/3
In this case, the number N of particles contained per 1 g of particles is expressed by the following formula.
Number of particles contained per gram of particle N = 1 / VG
Therefore, the theoretical specific surface area SD (m ² / g) of a true spherical particle having the same particle diameter as that of an elliptical or acicular polymer particle is represented by the following formula.
Theoretical specific surface area SD (m ² / g) = S′N = S ′ / VG = 3 / rG

(7) Measurement of total light transmittance of synthetic solution Using haze meter NDH-5000 (manufactured by Nippon Denshoku Industries Co., Ltd.), the synthetic solution was added to the square cell (10 × 36 × 55) attached to the apparatus and measured. .
(8) Measurement of total light transmittance and turbidity of light diffusion film Based on JIS K7136, 7361, it was measured using a haze meter NDH-5000 (manufactured by Nippon Denshoku Industries Co., Ltd.).
(9) Measurement of light diffusion performance Using an automatic variable angle photometer GP-200 (manufactured by Murakami Color Research Laboratory Co., Ltd.), the diffused light intensity at -90 ° to 90 ° was measured, and the obtained diffused light The intensity was calculated by calculating the radiance represented by the following formula, and the light diffusion performance was confirmed.
Radiance = diffuse light intensity / cos (θ)

(10) Measurement of water absorption The dried powder was dispersed in water at a concentration of about 2% by mass, allowed to stand for one day, dispersed again, and filtered under reduced pressure using a glass filter. The filtered glass filter was centrifuged at 3000 rpm for 30 minutes using a centrifuge (CR-20GII, manufactured by Hitachi High-Technologies Corporation), and then the powder obtained was dried and powder before and after drying. The mass was measured, and the difference was taken as the amount of absorbed water.
(11) Measurement of oil absorption amount Measured according to the oil law described in JIS K 5101.

[1] Elliptical or acicular polymer particles [Example 1]
A mixture prepared by mixing the compounds shown below in a 2000 ml flask at the following ratio is charged all at once. After replacing the dissolved oxygen with nitrogen, the mixture is heated with an agitator at an oil bath temperature of 88 ° C. for about 12 hours under a nitrogen stream. To obtain a styrene / p-sodium styrenesulfonate copolymer particle solution. The total light transmittance of the charged medium (including the monomer, hereinafter the same) was 58.8%. Further, before the polymerization, the emulsified part and the dissolved part coexisted in the medium.
240g of styrene
60 g of sodium p-styrenesulfonate
Butanol 400g
Methanol 200g
600g of water
Azobisisobutyronitrile (AIBN) 30g
Polyvinylpyrrolidone (K-30) 250g
SDS (sodium dodecyl sulfate) 6.0 g

Next, this particle solution was washed and filtered with methanol about 3 to 5 times using a known suction filtration equipment and vacuum-dried to obtain elliptical or needle-like polymer particles.
100 resulting particles were extracted at random, observation of the shape in SEM, the average major axis of the long diameter (L ₁₎ (L _1a) is 19.1Myuemu, numerous fine particles Deki aggregated Thus, it was confirmed to be an elliptical or acicular polymer particle having fine irregularities on the surface. Moreover, the average (P _1a ) of the aspect ratio (P ₁ ) was 6.2, and the volume average particle diameter when converted into a spherical shape measured using the particle size distribution was 8.5 μm. The melting point calculated from the temperature at which a peak due to melting was observed in a differential scanning calorimeter (DSC6200, manufactured by Seiko Instruments Inc.) was 115 ° C., the specific gravity was 1.09 g / cm ³ , and the specific surface area was 10. It was 4 m ² / g. SEM photographs of the obtained elliptical or acicular polymer particles are shown in FIGS.

[Example 2]
A mixture prepared by mixing the compounds shown below in a 2000 ml flask at the following ratio is charged all at once. After replacing the dissolved oxygen with nitrogen, the mixture is heated with a stirrer at an oil bath temperature of 90 ° C. for about 12 hours under a nitrogen stream. To obtain a styrene / p-sodium styrenesulfonate copolymer particle solution. The total light transmittance of the charged medium was 41.2%. Further, before the polymerization, the emulsified part and the dissolved part coexisted in the medium.
Styrene 225g
Sodium p-styrenesulfonate 75g
Butanol 400g
Methanol 200g
600g of water
Azobisisobutyronitrile (AIBN) 30g
Polyvinylpyrrolidone (K-30) 400g
SDS (sodium dodecyl sulfate) 6.0 g

Next, this particle solution was washed and filtered repeatedly with methanol about 3 to 5 times using a known suction filtration equipment, and vacuum dried to obtain elliptical or needle-like polymer particles.
100 resulting particles were extracted at random, observation of the shape in SEM, the average major axis of the long diameter (L ₁₎ (L _1a) is 5.0 .mu.m, a large number of fine particles Deki aggregated Thus, it was confirmed to be an elliptical or acicular polymer particle having fine irregularities on the surface. Moreover, the average (P _1a ) of the aspect ratio (P ₁ ) was 4.6, and the volume average particle diameter when converted into a spherical shape measured using the particle size distribution was 3.0 μm. The melting point calculated from the temperature at which a peak due to melting was observed in a differential scanning calorimeter (DSC6200, manufactured by Seiko Instruments Inc.) was 106 ° C., the specific gravity was 1.09 g / cm ³ , and the specific surface area was 91.000. 2 m ² / g. SEM photographs of the obtained elliptical or acicular polymer particles are shown in FIGS.

[Example 3]
Charge a mixture of the compounds shown below in a 500 ml flask at the same rate, replace the dissolved oxygen with nitrogen, and then heat for about 12 hours with a stirrer at an oil bath temperature of 90 ° C. under a nitrogen stream. As a result, a solution of n-butyl methacrylate / methacrylic acid copolymer particles was obtained. The total light transmittance of the charged medium was 63.8%. Further, before the polymerization, the emulsified part and the dissolved part coexisted in the medium.
48g of n-butyl methacrylate
Methacrylic acid 12g
Butanol 80g
40g of methanol
120g of water
Azobisisobutyronitrile (AIBN) 6.0 g
Polyvinylpyrrolidone (K-30) 60g
SDS (sodium dodecyl sulfate) 1.2 g

Next, this particle solution was washed and filtered repeatedly with a methanol solution about 3 to 5 times using a known suction filtration equipment and vacuum-dried to obtain elliptical or needle-like polymer particles.
100 resulting particles were extracted at random, observation of the shape in SEM, the average major axis of the long diameter (L ₁₎ (L _1a) is 13.2Myuemu, numerous fine particles Deki aggregated Thus, it was confirmed to be an elliptical or acicular polymer particle having fine irregularities on the surface. Further, the average (P _1a ) of the aspect ratio (P ₁ ) was 3.0, and the volume average particle diameter when converted into a spherical shape measured using the particle size distribution was 9.2 μm. The melting point calculated from the temperature at which a peak due to melting was observed in a differential scanning calorimeter (DSC6200, manufactured by Seiko Instruments Inc.) was 142 ° C., the specific gravity was 1.1 g / cm ³ , and the specific surface area was 10. It was 3 m ² / g.

[Example 4]
Charge a mixture of the compounds shown below in a 300 ml flask at the following ratio, replace the dissolved oxygen with nitrogen, and then heat for about 12 hours at 90 ° C. in an oil bath under nitrogen flow with a stirrer. Then, a styrene / Antox MS-60 (bis (polyoxyethylene diphenyl ether) methacrylate sodium sulfate) copolymer particle solution was obtained. In addition, the total light transmittance of the medium after preparation was 52.8%. Further, before the polymerization, the emulsified part and the dissolved part coexisted in the medium.
28g of styrene
Antox MS-60 (Nihon Emulsifier Co., Ltd.) 13.3g
Hexane 24g
Isopropyl alcohol 72g
48g of water
Azobisisobutyronitrile (AIBN) 4.0 g
Polyvinylpyrrolidone (K-30) 20g

Next, this particle solution was washed and filtered repeatedly with a methanol solution about 3 to 5 times using a known suction filtration equipment and vacuum-dried to obtain elliptical or needle-like polymer particles.
100 resulting particles were extracted at random, observation of the shape in SEM, the average major axis of the long diameter (L ₁₎ (L _1a) is 10.5 [mu] m, a large number of fine particles Deki aggregated Thus, it was confirmed to be an elliptical or acicular polymer particle having fine irregularities on the surface. Moreover, the average (P _1a ) of the aspect ratio (P ₁ ) was 3.6, and the volume average particle diameter when converted into a spherical shape measured using the particle size distribution was 7.5 μm. The melting point calculated from the temperature at which a peak due to melting was observed in a differential scanning calorimeter (DSC6200, manufactured by Seiko Instruments Inc.) was 78 ° C., the specific gravity was 1.1 g / cm ³ , and the specific surface area was 18. It was 3 m ² / g.

[Example 5]
A mixture prepared by mixing the compounds shown below in a 2000 ml flask at the following ratio is charged all at once. After replacing the dissolved oxygen with nitrogen, the mixture is heated with a stirrer at an oil bath temperature of 90 ° C. for about 12 hours under a nitrogen stream. To obtain a styrene / methacrylic acid copolymer particle solution. The total light transmittance of the charged medium was 27.8%. Further, before the polymerization, the emulsified part and the dissolved part coexisted in the medium.
270 g of styrene
Methacrylic acid 180g
480 g of butanol
240g methanol
600g of water
Azobisisobutyronitrile (AIBN) 90g
Polyvinylpyrrolidone (K-60) 150g
SDS (sodium dodecyl sulfate) 6.0 g

Next, this particle solution is washed with a water / methanol = 1: 1 mixed solution about 3 to 5 times using a known suction filtration equipment, washed and filtered repeatedly, and vacuum dried to obtain elliptical or needle polymer particles. It was.
100 resulting particles were extracted at random, observation of the shape in SEM, the average major axis of the long diameter (L ₁₎ (L _1a) is 1.8 .mu.m, a large number of fine particles Deki aggregated Thus, it was confirmed to be an elliptical or acicular polymer particle having fine irregularities on the surface. Further, the average (P _1a ) of the aspect ratio (P ₁ ) was 6.8, and the volume average particle diameter when converted into a spherical shape measured using the particle size distribution was 0.8 μm. The melting point calculated from the temperature at which a peak due to melting was observed in a differential scanning calorimeter (DSC6200, manufactured by Seiko Instruments Inc.) was 167 ° C., the specific gravity was 1.1 g / cm ³ , and the specific surface area was 112. It was 6 m ² / g.

[Comparative Example 1]
A 300 ml flask was charged with the mixture at the ratio shown below, and the dissolved oxygen was replaced with nitrogen. Then, the mixture was heated with a stirrer at an oil bath temperature of 65 ° C. for about 15 hours under a nitrogen stream, and styrene p- A sodium styrene sulfonate copolymer particle solution was obtained. The total light transmittance of the charged medium was 76.8%. Further, before polymerization, the medium was almost transparent.
Styrene 28.9g
Sodium p-styrenesulfonate 7.2g
Methanol 82.8g
55.2 g of water
Azobisisobutyronitrile (AIBN) 1.0 g
Polyvinylpyrrolidone (K-90) 10.0g

Next, this particle solution is washed with a water-methanol mixed solution (mass ratio 3: 7) about 3 to 5 times using a known suction filtration equipment, repeatedly washed and filtered, dried in vacuum, and then elliptical or needle-shaped polymer. Particles were obtained.
100 resulting particles were extracted at random, observation of the shape in SEM, a major axis (L ₁₎ average length of (L _1a) is 19.0Myuemu, elliptical or have a single continuous curved surface It was confirmed to be acicular polymer particles. Moreover, the average (P _1a ) of the aspect ratio (P ₁ ) was 5.9, and the volume average particle diameter when converted into a spherical shape measured using the particle size distribution was 8.5 μm. The melting point calculated from the temperature at which a peak due to melting was observed in a differential scanning calorimeter (DSC6200 manufactured by Seiko Instruments Inc.) was 151 ° C., the specific gravity was 1.09 g / cm ³ , and the specific surface area was 1.5 m. ² / g. An SEM photograph of the obtained elliptical or acicular polymer particles is shown in FIG.

[Comparative Example 2]
Charge a mixture of the compounds shown below in a 500 ml flask at the same rate, replace the dissolved oxygen with nitrogen, and heat for about 12 hours at an oil bath temperature of 78 ° C. under a nitrogen stream with a stirrer. To obtain a styrene polymerized particle solution. The total light transmittance of the charged medium was 95.8%. Further, only the solution portion was present in the medium before polymerization.
86g of styrene
184g of methanol
Ethanol 46g
Azobisisobutyronitrile (AIBN) 7.29 g
Polyvinylpyrrolidone (K-30) 24.5g

Next, this particle solution was repeatedly washed and filtered with methanol about 3 to 5 times using a known suction filtration equipment, and vacuum dried to obtain spherical particles.
The volume-average particle diameter in terms of sphere measured using the particle size distribution was 8.5 μm. The melting point calculated from the temperature at which a peak due to melting was observed in a differential scanning calorimeter (DSC6200, manufactured by Seiko Instruments Inc.) was 101 ° C., the specific gravity was 1.10 g / cm ³ , and the specific surface area was 0.1. It was 85 m ² / g.

[Comparative Example 3]
Charge a mixture of the compounds shown below in a 500 ml flask at the same rate, replace the dissolved oxygen with nitrogen, and heat for about 12 hours at an oil bath temperature of 78 ° C. under a nitrogen stream with a stirrer. To obtain a styrene polymerized particle solution. The total light transmittance of the charged medium was 93.2%. Further, only the solution portion was present in the medium before polymerization.
86g of styrene
Methanol 230g
Azobisisobutyronitrile (AIBN) 6.08 g
Polyvinylpyrrolidone (K-30) 35g

Next, this particle solution was repeatedly washed and filtered with methanol about 3 to 5 times using a known suction filtration equipment, and vacuum dried to obtain spherical particles.
The volume average particle diameter in terms of spherical shape measured using the particle size distribution was 3.0 μm. The melting point calculated from the temperature at which a peak due to melting was observed in a differential scanning calorimeter (DSC6200, manufactured by Seiko Instruments Inc.) was 101 ° C., the specific gravity was 1.10 g / cm ³ , and the specific surface area was 2. It was 75 m ² / g.

[Comparative Example 4]
A mixture prepared by mixing the compounds shown below in a 500 ml flask at the following ratio is charged all at once. After replacing the dissolved oxygen with nitrogen, the mixture is heated with an agitator under a nitrogen stream at an oil bath temperature of 90 ° C. for about 12 hours. To obtain a styrene polymerized particle solution. The total light transmittance of the charged medium was 10.3%. Further, only the emulsified portion was present in the medium before polymerization.
Styrene 82.8g
SDS (sodium dodecyl sulfate) 2.0 g
Water 292.8g
Sodium bicarbonate 0.075g
Potassium persulfate 0.193g

Next, this particle solution is centrifuged at 10,000 rpm for 30 minutes using a centrifuge (CR-20GII, manufactured by Hitachi High-Technologies Corporation), and after removing the supernatant, methanol is added to disperse the particles. I let you. The same centrifugal separation operation was repeated about 3 to 5 times, followed by vacuum drying to obtain styrene polymer particles.
When the shape of the obtained particles was observed with an SEM, it was a true spherical particle, and the target elliptical or acicular polymer particles could not be obtained. The volume average particle diameter in terms of spherical shape measured using the particle size distribution was 0.4 μm. The melting point calculated from the temperature at which a peak due to melting was observed in a differential scanning calorimeter (DSC6200, manufactured by Seiko Instruments Inc.) was 101 ° C., the specific gravity was 1.10 g / cm ³ , and the specific surface area was 16. It was 4 m ² / g.

  Table 1 shows the volume average particle diameter, specific surface area (SB), theoretical specific surface area (SD), and ratio (SB) / (SD) of the particles obtained in Examples 1-5 and Comparative Examples 1-4. Shown in

[2] Light diffusion sheet [Example 6]
The following components were mixed to prepare a composition, and coated on one side of a 100 μm thick PET film (E-5000, manufactured by Toyobo Co., Ltd., the same applies hereinafter). After coating, hot air drying was performed with a drier to prepare a light diffusing sheet 1 having a coating layer thickness of 100 μm.
Binder resin: Acrylic resin (resin content 45%) 41.3g
Polymer particles: Ellipsoidal or acicular polymer particles of Example 1 10 g
Acrylic resin: Joncrill 511 manufactured by BASF Japan (the same applies hereinafter)

[Example 7]
The following components were mixed to prepare a composition, and coated on one side of a PET film having a thickness of 100 μm. After coating, hot air drying was performed with a drier to prepare a light diffusion sheet 2 having a coating layer thickness of 100 μm.
Binder resin: Acrylic resin (resin content 45%) 41.3g
Polymer particles: Ellipsoidal or acicular polymer particles of Example 2 10 g

[Comparative Example 5]
The following components were mixed to prepare a composition, and coated on one side of a PET film having a thickness of 100 μm. After coating, hot air drying was performed with a drier to prepare a light diffusion sheet 3 having a coating layer thickness of 100 μm.
Binder resin: Acrylic resin (resin content 45%) 41.3g
Polymer particles: 10 g of elliptical or acicular polymer particles of Comparative Example 1

[Comparative Example 6]
The following components were mixed to prepare a composition, and coated on one side of a PET film having a thickness of 100 μm. After coating, hot air drying was performed with a drier to prepare a light diffusing sheet 4 having a coating layer thickness of 100 μm.
Binder resin: Acrylic resin (resin content 45%) 41.3g
Polymer particles: 10 g of spherical particles of Comparative Example 2

[Comparative Example 7]
The following components were mixed to prepare a composition, and coated on one side of a PET film having a thickness of 100 μm. After coating, hot air drying was performed with a drier to prepare a light diffusion sheet 5 having a coating layer thickness of 100 μm.
Binder resin: Acrylic resin (resin content 45%) 41.3g
Polymer particles: 10 g of spherical particles of Comparative Example 3
The total light transmittance and haze of the light diffusing sheets obtained in Examples 6 and 7 and Comparative Examples 5 to 7 are shown in Table 2, and the light diffusing sheets 1 and 1 obtained in Example 6 and Comparative Examples 5 and 6 are shown in Table 2. The radiance distribution using the automatic variable angle photometers 3 and 4 is shown in FIG. 9, and the radiance distribution using the automatic variable angle photometer of the light diffusion sheets 2 and 5 obtained in Example 7 and Comparative Example 7 is shown in FIG. Is shown in FIG.

[3] Cosmetic application The water absorption and oil absorption of the particles obtained in Examples 1 and 2 and Comparative Examples 1 to 3 were measured, and the touch, slipperiness and glossiness when applied to the skin were evaluated. The results are shown in Table 3.

○: Extremely good, Δ: Good, ×: Poor

2 is a view showing an SEM photograph (× 1000) of elliptical or acicular polymer particles obtained in Example 1. FIG. 2 is a view showing an SEM photograph (× 30000) of elliptical or acicular polymer particles obtained in Example 1. FIG. 3 is a view showing an SEM photograph (× 35000) of a cross section of an elliptical or acicular polymer particle obtained in Example 1. FIG. 4 is a view showing an SEM photograph (× 3000) of elliptical or acicular polymer particles obtained in Example 2. FIG. 4 is a diagram showing an SEM photograph (× 40000) of elliptical or acicular polymer particles obtained in Example 2. FIG. 4 is a diagram showing an SEM photograph (× 80000) of elliptical or acicular polymer particles obtained in Example 2. FIG. 4 is a view showing an SEM photograph (× 100,000) of elliptical or acicular polymer particles obtained in Example 2. FIG. 4 is a view showing an SEM photograph (× 2000) of elliptical or acicular polymer particles obtained in Comparative Example 1. FIG. It is a figure which shows the radiance distribution using the automatic variable angle photometer of the sheet | seat for light diffusion obtained in Example 6 and Comparative Examples 5 and 6. FIG. It is a figure which shows the radiance distribution using the automatic variable angle photometer of the sheet | seat for light diffusion obtained in Example 7 and Comparative Example 7. FIG.

Claims (12)

Oval or acicular polymer particles having fine irregularities on the surface,
The polymer particles are styrene monomer, (meth) acrylate monomer, styrene sulfonate, styrene carboxylate, (meth) acrylate, (meth) acrylate carboxylate, and ( Particles consisting of at least one polymer selected from (meth) acrylic acid ester sulfonates,
Aspect ratio (P ₁ ) = major axis (L) calculated from the major axis (L ₁ ) and minor axis (D ₁ ) of the projection two-dimensional view obtained by irradiating light from the direction orthogonal to the major axis direction of the particles ₁₎ / short diameter (D ₁₎ is less than the (P ₁₎ ≧ 1.8, and a specific surface area of the particles, elliptical or needle-like polymer particles and satisfies the following formula (1) .
(SB) / (SD) ≧ 5 (1)
(In the formula, SB means the actual specific surface area of the particles, and SD means the theoretical specific surface area of true spherical particles calculated from the average particle diameter of the particles.) The elliptical or acicular polymer particle according to claim 1, wherein the particle has a specific surface area of 10 m ² / g or more . Average length (L _1a) is elliptical or needle-like polymer particles of claim 1 or 2 wherein the 0.01~500μm of the major axis (L _1). The elliptical or acicular polymer particle according to any one of claims 1 to 3, which is porous . A method for producing elliptical or acicular polymer particles in which a monomer is solution polymerized in the presence of a solvent, comprising:
Wherein a total light transmittance of the reaction medium, including the monomer 20 to 70% of the elliptical or acicular polymer particles of claim 1 Symbol placement perform the polymerization under conditions where the emulsification portion and lysing portion coexist Manufacturing method . The solvent method of elliptical or acicular polymer particles of claim 5 Symbol mounting a mixed solvent composed of water and a water-soluble organic solvent. The method for producing elliptical or acicular polymer particles according to claim 6 , wherein the solvent further contains a hydrophobic organic solvent . The resin composition containing the elliptical or acicular polymer particle of any one of Claims 1-4 . A light diffusing sheet comprising the elliptical or acicular polymer particles according to claim 1 . A cosmetic member using the elliptical or acicular polymer particles according to any one of claims 1 to 4 . The coloring material which uses the elliptical or acicular polymer particle of any one of Claims 1-4 . The coating material using the elliptical or acicular polymer particle of any one of Claims 1-4 .