JP5530586B2 - Resin particles and their use - Google Patents

Description

  The present invention relates to resin particles and uses thereof. More specifically, the present invention is a resin having an extremely excellent tactile sensation (smoothness, soft feel) and an extremely uniform spreadability at the time of coating, dropout of particles, dispersibility in an aqueous medium, and redispersibility. It relates to particles and their uses. The resin particles of the present invention can be suitably used as a coating film softening agent, a matting agent for paints, and the like.

Some car interior parts have a matte finish. Such matte paint finish has been performed using a matting agent in which a pigment for gloss adjustment represented by silica or talc is added to the paint.
However, the coating film obtained by the matting agent has a problem that it has a hard feel and is easily scratched when an impact is applied from the outside.
Therefore, a coating film having high scratch resistance, soft texture (soft feel) and smooth texture is demanded.

As a method of imparting a unique pattern or soft texture to the coating film and improving scratch resistance, slip agents in the paint, such as acrylic resin particles, urethane resin particles, nylon resin particles, silicon resin particles, polyethylene resin particles The method of adding etc. is generally known.
Japanese Patent Laid-Open No. 2000-186017 (Patent Document 1) discloses a nonporous material having an average particle diameter of 0.5 to 30 μm formed by adhering inorganic powder to the surface and a compressive strength of 0.05 to 0.6 kg / mm ^2. It is described that the true spherical cross-linked (meth) acrylic ester resin particles can improve the feel of external preparations such as cosmetics and paints.
Examples of Patent Document 1 include 1,6-hexanediol dimethacrylate, caprolactone-modified pentaerythritol hexaacrylate, tetraethylene glycol dimethacrylate, and ethylene glycol dimethacrylate.

Japanese Patent Application Laid-Open No. 2002-265620 (Patent Document 2) describes a compressive strength at 10% deformation as a resin that is excellent in dispersibility and can impart a good feeling such as soft feeling, elongation, and smoothness to an external preparation. (Meth) acrylic acid characterized in that 5 to 100 parts by weight of an organic solvent aqueous solution is contained in 100 parts by weight of crosslinked (meth) acrylic ester resin particles of 0.01 to 0.6 kgf / mm ^2. An ester-based resin particle wet product and an external preparation containing the wet product are described.
Examples of Patent Document 2 include 1,6-hexanediol dimethacrylate and tetraethylene glycol dimethacrylate.

Furthermore, Japanese Patent Application Laid-Open No. 2004-099700 (Patent Document 3) describes a coating composition containing porous (meth) acrylic acid ester polymer particles, and the particles have a particle size of 10 by applying a load. It is described that it has a compressive strength of 0.05 to 0.6 kgf / mm ² when deformed in%.
Examples of Patent Document 3 include 1,6-hexanediol dimethacrylate and diethylene glycol dimethacrylate.
JP-A-5-156171 (Patent Document 4) describes a resin composition in which a fine polymer is dispersed in a synthetic resin. This publication describes that the resin composition can improve impact resistance and solvent resistance, can impart light diffusibility, and can suppress adverse effects caused by the emulsifier derived from the fine particulate polymer.

JP 2000-186017 A JP 2002-265620 A JP 2004-099700 A JP-A-5-156171

  The above conventional technique is not sufficient, and it has been desired to provide resin particles capable of providing a coating film having further improved characteristics (particularly, scratch resistance and soft touch).

As a result of intensive efforts, the present inventors have found that the above-mentioned problems can be solved by resin particles having a restoration rate of 15% to 30%, and have completed the present invention.
Thus, according to the invention, the general formula (I):
_{CH 2 = C (CH 3)} -COO- (CH 2 CH 2 O) n -CO-C (CH 3) = CH 2
(In the formula, n is an integer of 5 to 20)
And a polymer of a mixture containing at least 10 to 50% by weight and 90 to 50% by weight of a crosslinkable monomer having vinyl groups at both ends of the molecule and (meth) acrylic acid ester, and Resin particles having a restoration rate of 15% to 30% are provided.

ADVANTAGE OF THE INVENTION According to this invention, when it is made to contain in the coating composition for coating-film formation, the resin particle which can form a coating film with a flexible and matt effect can be provided. Since the resin particles of the present invention are soft themselves, the resulting coated film can be provided with a soft touch, a smooth touch, and a texture free of roughness by including the resin particles in the coating composition. Can do. The resin particles of the present invention are very excellent in dispersibility and redispersibility in a solvent.
Moreover, when the resin particles of the present invention are used as a paint matting agent or the like, an excellent scratch-resistant coating film can be obtained.

In the presence of a suspension stabilizer, the resin particles of the present invention are represented by the general formula (I):
_{CH 2 = C (CH 3)} -COO- (CH 2 CH 2 O) n -CO-C (CH 3) = CH 2
(In the formula, n is an integer of 5 to 20)
It is obtained by subjecting a mixture containing at least a crosslinkable monomer having an ethyleneoxy group repeating unit and a vinyl group to both ends of the molecule and (meth) acrylic acid ester to aqueous suspension polymerization. . In addition, (meth) acryl means methacryl or acryl.

  Examples of the crosslinkable monomer represented by the general formula (I) include pentaethylene glycol di (meth) acrylate, hexaethylene glycol di (meth) acrylate, heptaethylene glycol di (meth) acrylate, and octaethylene glycol. Examples include di (meth) acrylate, nonaethylene glycol di (meth) acrylate, decaethylene glycol di (meth) acrylate, tetradecaethylene glycol di (meth) acrylate, and pentadecaethylene glycol di (meth) acrylate.

  Other crosslinkable monomers having vinyl groups other than the general formula (I) at both ends of the molecule may be used. Examples of such other crosslinkable monomers include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, and 1,3. -Butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, glycerin di (meth) acrylate, trimethylolpropane tri (meth) acrylate, penta Erystol tetra (meth) acrylate, diethylene glycol phthalate di (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, caprolactone-modified hydroxypivalate ester Neope Chill glycol diacrylate, polyester acrylate, (meth) acrylic ester monomer such as urethane acrylate, divinyl benzene, aromatic divinyl monomers divinyl naphthalene, and derivatives thereof.

Among them, nonaethylene glycol di (meth) acrylate (n = 9) and tetradecaethylene glycol di (meth) acrylate (n = 14) are particularly preferable for obtaining soft resin particles. In the present invention, the term “soft” means that the compression strength described below is in the range of 0.05 to 0.6 kgf / mm ² .
The crosslinkable monomer of the general formula (I) is used in a proportion of 10 to 50% by weight based on the total amount of the crosslinkable monomer of the general formula (I) and the (meth) acrylic acid ester.

  If the proportion of the other crosslinkable monomer used is increased, the resin particles become hard, which is not preferable because the softness of the coating film obtained using the resin particles is impaired. Therefore, the other crosslinkable monomer is preferably used in a proportion of 25% by weight or less based on the total amount of the crosslinkable monomer of the general formula (I) and the other crosslinkable monomer. . Further, when the proportion of other crosslinkable monomer used is reduced, the solvent resistance may be inferior when preparing a solvent-based coating composition. Therefore, the other crosslinkable monomer is preferably used in a proportion of 1% by weight or more based on the total amount of the crosslinkable monomer of the general formula (I) and the other crosslinkable monomer. . A more preferable use ratio of the other crosslinkable monomer is in the range of 4 to 12% by weight.

  Moreover, it does not specifically limit as (meth) acrylic acid ester, All can use well-known (meth) acrylic acid ester. Among known (meth) acrylic acid esters, although depending on the degree of polymerization, it is preferable to use a (meth) acrylic acid ester monomer having a single polymer having a glass transition temperature of 20 ° C. or lower. By using such a monomer, it is possible to provide resin particles that can improve scratch resistance and can provide a softer feel.

Examples of the (meth) acrylic acid ester monomer having a glass transition temperature of 20 ° C. or lower of the polymer include acrylic acid esters such as ethyl acrylate, n-butyl acrylate, isobutyl acrylate, and 2-ethylhexyl acrylate. And methacrylates such as n-butyl methacrylate and 2-ethylhexyl methacrylate.
Said (meth) acrylic acid ester-type monomer can be used individually or in combination of 2 or more types, respectively.

  A (meth) acrylic acid ester monomer having a glass transition temperature of 20 ° C. or higher may be used together with a monomer having a glass transition temperature of 20 ° C. or lower. Examples of such monomers include methyl acrylate, methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, isobornyl methacrylate, 2-hydroxyethyl methacrylate, 2-methoxy methacrylate. Examples include ethyl, glycidyl methacrylate, tetrahydrofurfuryl methacrylate, diethylaminoethyl methacrylate, trifluoroethyl methacrylate, heptadecafluorodecyl methacrylate, and the like.

Among these monomers, in order to sufficiently improve the mechanical strength of the resin particles, for example, to prevent the destruction of the resin particles due to the kneading share when preparing the coating composition, an alkyl group having 1 to 8 carbon atoms is used. An acrylic ester having an alkyl group having 1 to 4 carbon atoms is more preferable.
The use ratio of the (meth) acrylic acid ester is 50 to 90% by weight, more preferably 60 to 80%, based on the total amount of the crosslinkable monomer of the general formula (I) and the (meth) acrylic acid ester. % By weight.
In addition, as long as the performance of the obtained resin particles does not fall, other monomers that can be copolymerized with (meth) acrylate monomers are used in combination with (meth) acrylate monomers. May be.

As said other copolymerizable monomer, what has vinyl groups, such as styrene, p-methylstyrene, (alpha) -methylstyrene, vinyl acetate, is mentioned, for example. These monomers can be used alone or in combination of two or more.
In the suspension polymerization, a polymerization initiator is used as necessary.
Examples of the polymerization initiator include oil-soluble peroxides such as benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, benzoyl orthochloroperoxide, methyl ethyl ketone peroxide, diisopropyl peroxydicarbonate, cumene hydroperoxide, and t-butyl hydroperoxide. Examples thereof include oil-soluble azo compounds such as oxides, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile).

These polymerization initiators can be used alone or in combination of two or more.
The amount of the polymerization initiator used is about 0.1 to 1 part by weight with respect to 100 parts by weight of the total amount of the crosslinkable monomer of the general formula (I) and the (meth) acrylic acid ester.
Moreover, you may use a dispersing agent and / or surfactant, etc. for suspension polymerization.
Examples of such a dispersant include poorly water-soluble inorganic salts such as calcium phosphate and magnesium pyrophosphate, and water-soluble polymers such as polyvinyl alcohol, methyl cellulose, and polyvinyl pyrrolidone.

  Examples of the surfactant include anionic surfactants such as sodium olefinate, sodium lauryl sulfate, sodium dodecylbenzene sulfonate, alkyl naphthalene sulfonate, alkyl phosphate ester salt, polyoxyethylene alkyl ether, polyoxy Nonionic surfactants such as ethylene alkylphenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxysorbitan fatty acid ester, polyoxyethylene alkylamine, glycerin fatty acid ester, amphoteric surfactants such as lauryl dimethylamine oxide, etc. Is mentioned.

These dispersants and surfactants can be used alone or in combination of two or more. Among these, from the viewpoint of dispersion stability, it is preferable to use a combination of a poorly water-soluble phosphate dispersant such as calcium phosphate and magnesium pyrophosphate and an anionic surfactant such as alkyl sulfate and alkyl benzene sulfonate. .
The use ratio of the dispersant is about 0.5 to 10 parts by weight with respect to 100 parts by weight of the total amount of the crosslinkable monomer of the general formula (I) and the (meth) acrylic ester, and the use ratio of the surfactant. Is about 0.01 to 0.2% by weight based on 100 parts by weight of the aqueous medium.

  In the polymerization reaction, an oil phase (for example, a monomer, a polymerization initiator, a non-polymerizable organic solvent, etc.) and an aqueous phase (for example, an aqueous medium, a dispersant, a surfactant, etc.) are mixed and then heated while stirring. To get started. The aqueous phase is preferably used in an amount of 100 to 1000 parts by weight with respect to 100 parts by weight of the oil phase. Examples of the aqueous medium include water and a mixture of water and a water-soluble organic solvent (for example, a lower alcohol).

  The polymerization temperature is preferably about 40 to 90 ° C. The polymerization time while maintaining the reaction system at the polymerization temperature is usually about 1 to 10 hours. The average particle diameter of the resin particles can be appropriately controlled by adjusting the mixing ratio of the oil phase and the aqueous phase, the dispersant, the amount of surfactant used, the stirring conditions, and the dispersion conditions.

As a method to disperse the oil phase in the water phase with fine droplets, a method using a stirring force such as a propeller blade, a homogenizer, an emulsifying disperser using a high shear applied to the gap between the rotating blade and the wall or between the rotating blades. Examples thereof include a method used, an ultrasonic disperser, a method using a high-pressure jet disperser, and the like. For example, in the case of a homogenizer, when the number of rotations is large and the dispersion time is long, the obtained droplet diameter tends to be small.
After the completion of the polymerization reaction, the desired resin particles can be obtained by decomposing and removing the dispersant with an acid or the like as desired, followed by filtration, water washing, dehydration, drying, pulverization, and classification.

As for the average particle diameter of the resin particle used for this invention, 3-100 micrometers is preferable, More preferably, it is the range of 5-60 micrometers. Resin particles having an average particle diameter within this range are preferred because they can further improve the matte and finished appearance.
When the average particle diameter is less than 3 μm, the unevenness formed in the matte coating film is small, and therefore, a substantial matting effect may not be obtained.
In addition, when the average particle diameter of the particles exceeds 100 μm, the appearance when the matte coating film is formed may be rough, which is not preferable because the finished appearance may be deteriorated.
The obtained resin particles may be isolated from the aqueous medium by a known method.

In order to prevent coalescence of the isolated resin particles, an inorganic powder may be attached to the surface of the obtained resin particles, or a mixture of resin particles and an appropriate amount of inorganic powder may be used. Examples of the inorganic powder include silica, alumina, titania, zirconia, ceria, iron oxide, and zinc oxide.
The inorganic powder preferably has an average particle diameter of 1/10000 to 1/100 of the average particle diameter of the resin particles, and preferably has an average particle diameter of 1/3000 to 1/900. More preferred. Specifically, the average particle diameter of the inorganic powder is preferably 1 to 100 nm, more preferably 2 to 50 nm, and most preferably 10 to 15 nm.

Furthermore, the inorganic powder is preferably used in an amount of 0.1 to 5% by weight, and more preferably 1.0 to 3.0% by weight, based on the total of the inorganic powder and the resin particles.
The resin particles of the present invention have a restoration rate of 15 to 30%. If the restoration rate is less than 15%, the scratch resistance of the coating film containing the resin particles may be lowered, which is not preferable. If it is more than 30%, the particle shape of the resin particles cannot be maintained, which is not preferable. A more preferable restoration rate is 16 to 28%. The restoration rate is a value obtained by measurement with a micro compression tester HCTM200 manufactured by Shimadzu Corporation.

The resin particles preferably has a compressive strength in the range of 0.05~0.6kgf / mm ^2, and has a compressive strength in the range of 0.1~0.4kgf / mm ² It is more preferable. When the compressive strength is less than 0.05 kgf / mm ² , for example, the resin particles may collapse due to the kneading share when producing a matting agent for paint, which is not preferable. On the other hand, if the compressive strength exceeds 0.6 kgf / mm ² , the touch feeling of the coating film containing the resin particles may be felt hard, which is not preferable. The compressive strength is a value obtained by measurement with a micro compression tester HCTM200 manufactured by Shimadzu Corporation.

The resin particles of the present invention preferably have both compressive strength and restoration rate that satisfy a specific range. Specifically, the compressive strength is preferably in the range of 0.05 to 0.6 kgf / mm ² , and the restoration rate is preferably in the range of 15 to 30%, and the compressive strength is 0.1 to 0.4 kgf / mm ^2. in the range of mm ^2, and more preferably recovery ratio is in the range 16-20%.

Since the resin particles of the present invention are soft resin particles having the specific compressive strength and restoration rate, they can be suitably used as a coating film softening agent or a paint matting agent.
The resin particles of the present invention can be contained in a coating composition as a coating film softening agent or a coating matting agent. The coating composition contains a binder resin and a solvent as necessary. As the binder resin, an organic solvent, a water-soluble resin, 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 amount of binder resin and resin particles added varies depending on the film thickness of the coating film to be formed, the average particle diameter of the resin particles, and the coating method. The addition amount of the binder resin is preferably 5 to 50% by weight, more preferably 10 to 50% by weight, based on the total of the binder resin (solid content when an emulsion type aqueous resin is used) and the resin particles. More preferred is ˜40% by weight.

  If the content of the resin particles is less than 5% by weight, the matte effect may not be sufficiently obtained, which is not preferable. On the other hand, when the content exceeds 50% by weight, the viscosity of the coating composition becomes too high, and thus the resin particles may be poorly dispersed. For this reason, it is not preferable because appearance defects such as generation of micro cracks in the obtained coating film and roughness of the coating film surface occur.

For coating compositions, known coating surface conditioners, fluidity conditioners, UV absorbers, light stabilizers, curing catalysts, extender pigments, color pigments, metal pigments, mica powder pigments, dyes, organics, if necessary A solvent or the like may be contained.
Although it does not specifically limit as a solvent which comprises a coating composition, It is preferable to use the solvent which can melt | dissolve or disperse | distribute binder resin. For example, for oil-based paints, 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, ethylene glycol diethyl ether, ethylene glycol And ether solvents such as monobutyl ether. If it is a water-based paint, water, alcohols, etc. can be used. These solvents may be used alone or in combination of two or more.
The solvent content in the coating composition is usually about 20 to 60% by weight based on the total amount of the coating composition.

  The formation method of the coating film using a coating composition is not specifically limited, Any well-known method can be used. For example, a spray coating method, a roll coating method, a brush coating method, or the like can be used. The coating composition may be diluted 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.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto. In addition, the measuring method of the average particle diameter and compressive strength in the following examples is described below.
[Average particle size]
The average particle diameter of the resin particles in the present invention is a weight average particle diameter, and the average particle diameter of each resin particle obtained in the following Examples and Comparative Examples is measured using a Coulter Multisizer II manufactured by Coulter. .
The aperture tube used for the measurement is an aperture tube having a pore diameter of 50 μm for resin particles having an average particle diameter of less than 10 μm, and fine for resin particles having an average particle diameter of 10 to 30 μm. Using an aperture tube with a pore diameter of 100 μm and an aperture tube with a pore diameter of 280 μm for resin particles with an average particle diameter exceeding 30 μm, the average particle diameter obtained in the following examples and comparative examples was measured. did.

[Compressive strength]
The compressive strength of the resin particles is determined by measuring the amount of deformation and the load of the resin particles when a load of 1 gf is applied to one resin particle at a constant load speed using a micro compression tester MCTM2000 manufactured by Shimadzu Corporation. The load when the particle diameter is deformed by 10% and the particle radius before compression are expressed by the following formula:
Compressive strength (kgf / mm ² ) = 2.8 × load (kgf) / {π × (particle radius (mm)) ² }
It is a value obtained by counting into.
Measurement conditions and sample preparation of compressive strength (S10 strength) of resin particles; each resin particle obtained in the following examples and comparative examples was dispersed in ethanol, and then applied and dried on a sample stage, and a measurement sample To prepare.
Test temperature: Room temperature Test indenter: Flat 50 (flat indenter with a diameter of 50 μm)
・ Test type: Compression test (MODE1)
Test load: 1.00 (gf)
・ Loading speed: 0.072500 (gf / sec)
・ Displacement full scale: 10 (μm)

[Restore rate]
The restoration rate is based on the restoration amount due to the displacement from the particle diameter when the load is applied to the resin particles to the particle diameter when the load is reduced to 0.2 gf, and the particle diameter before the load is applied. ,formula:
Restoration rate (%) = restoration amount (μm) ÷ particle diameter (μm) × 100
Is calculated by

[Number average molecular weight]
The number average molecular weight (Mn) of the crosslinkable monomer is measured under the following conditions using GPC (manufactured by Tosoh Corporation: HLC-8020).
Column: “TSK GEL” (manufactured by Tosoh Corporation) G-1000H, G-2000H, G-4000H
・ Outflow: Tetrahydrofuran ・ Outflow rate: 1 ml / min ・ Outflow temperature: 40 ° C.

[Production of resin particles]
Example 1
Resin particles were produced using an oil phase and an aqueous phase comprising the composition in the proportions shown below.
(Oil phase)
80 parts by weight of butyl acrylate 20 parts by weight of tetradecaethylene glycol dimethacrylate “Light Ester 14EG” manufactured by Kyoeisha Chemical Co., Ltd.
(In formula (I), n = 14; number average molecular weight 780)
Benzoyl peroxide 0.3 parts by weight (aqueous phase)
400 parts by weight of deionized water Polyvinyl alcohol (degree of saponification 85%) 8 parts by weight Sodium lauryl sulfate 0.04 parts by weight Silica 3 parts by weight (R974 manufactured by Nippon Aerosil Co., Ltd., average particle size 12 nm)
The above oil phase was dispersed in the water phase at a rotation speed of 5000 rpm using a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd., tabletop TK homomixer). This dispersion was put into a polymerization reactor equipped with a stirrer, a heating device and a thermometer, and suspension polymerization was carried out by continuing stirring at 60 ° C. for 6 hours.
This suspension was filtered under reduced pressure, the resulting reaction product was washed with water, silica was added separately before and after drying, dried and pulverized to obtain resin particles having an average particle size of 7.8 μm. The restoration rate of the obtained resin particles was 26%.

Example 2
Tetradecaethylene glycol dimethacrylate (general formula I n = 14) was changed to nonaethylene glycol dimethacrylate (general formula I n = 9) (Kyoeisha Chemical Co., Ltd. “Light Ester 9EG”; number average molecular weight 560) Except that, resin particles having an average particle diameter of 7.9 μm were obtained in the same manner as in Example 1. The restoration rate of the obtained resin particles was 20%.
Example 3
Resin particles having an average particle diameter of 8.0 μm were obtained in the same manner as in Example 1 except that butyl acrylate was changed to butyl methacrylate. The restoration rate of the obtained resin particles was 18%.

Example 4
Example 1 except that butyl acrylate was changed to butyl methacrylate and tetradecaethylene glycol dimethacrylate (general formula I n = 14) was changed to nonaethylene glycol dimethacrylate (general formula I n = 9). Thus, resin particles having an average particle diameter of 7.9 μm were obtained. The restoration rate of the obtained resin particles was 16%.
Example 5
Resin particles having an average particle diameter of 7.9 μm were obtained in the same manner as in Example 1 except that silica was not added. The restoration rate of the obtained resin particles was 27%.

Comparative Example 1
The average particle size was 7.8 μm in the same manner as in Example 1 except that tetradecaethylene glycol dimethacrylate (n = 14 in general formula I) was changed to ethylene glycol dimethacrylate (n = 1 in general formula I). Resin particles were obtained. The restoration rate of the obtained resin particles was 11%.
Comparative Example 2
Example 1 was repeated except that butyl acrylate was changed to butyl methacrylate and tetradecaethylene glycol dimethacrylate (general formula I n = 14) was changed to ethylene glycol dimethacrylate (general formula I n = 1). Thus, resin particles having an average particle diameter of 7.8 μm were obtained. The restoration rate of the obtained resin particles was 2%.

Comparative Example 3
The average particle size was 7.8 μm in the same manner as in Example 1 except that tetradecaethylene glycol dimethacrylate (n = 14 in general formula I) was changed to tetraethylene glycol dimethacrylate (n = 4 in general formula I). Resin particles were obtained. The restoration rate of the obtained resin particles was 13%.
Comparative Example 4
Example 1 except that butyl acrylate was changed to butyl methacrylate and tetradecaethylene glycol dimethacrylate (general formula I n = 14) was changed to tetraethylene glycol dimethacrylate (general formula I n = 4). Thus, resin particles having an average particle diameter of 7.8 μm were obtained. The restoration rate of the obtained resin particles was 5%.

[Manufacture of paint]
3 parts by weight of each resin particle obtained in Examples 1 to 5 and Comparative Examples 1 to 4, and 20 parts by weight of a commercially available aqueous resin binder liquid (solid content 30%, manufactured by ALBERDINGK, trade name “U330”) The mixture was mixed for 10 minutes using a stirring deaerator and deaerated for 1 minute to obtain a paint.
The coating material was allowed to stand at 30 ° C. for 30 days and then shaken by hand, and the number of shaking until all the settled resin particles were uniformly dispersed was used as an index for evaluating the redispersibility of the resin particles.
In addition, evaluation was set to (circle) when the frequency | count of shaking was less than 20 times and disperse | distributed, and when exceeded 20 times, it was set as x.

[Manufacture of coating film]
A coating film was obtained by applying the obtained paint on a polyester film and drying using a coating apparatus in which a blade having a clearance of 100 μm was set.
The obtained coating film was evaluated by the following method.
1. Scratch resistance evaluation In the scratch resistance evaluation, scratches were scratched with a nail one week after formation of the coating film produced as described above, and ◯ indicates that no streak remained, and × indicates that white streak remained.

2. Evaluation of Tactile Feel Using a friction tester (KES-SE-DC FRICTION TESTER manufactured by Kato Tech Co., Ltd.), the friction characteristics of the coating film surface were measured.
Sample preparation: The coating film was allowed to stand at 20 ° C. and 60% RH for 48 hours, and then mounted on a tester sample stage.
Measurement conditions: Each part (a) and (b) of the tester was set as follows, and then operated using a KES-FB SYSTEM data measurement program ver. 6.46WJ manufactured by Kato Tech Co., Ltd. (c). After the operation was completed, the MIU value and MMD value calculated by the program were used as measured values of the friction coefficient.
Here, MIU is the average friction coefficient, MMD is the average deviation of the friction coefficient, MIU is the surface slipperiness, and MMD is the surface roughness.
Therefore, if MIU is 1.3 or less, the surface is smooth, and if MMD is 0.008 or less, there is little roughness and tactile sensation is good.

(A) Setting of KES-SE-STP SURFACE TESTER SENS; H
SPEED: 0.5 mm / sec (b) KES-SE-STP Friction Tester setting Friction; Silicone rubber friction, Friction load; 25 gf
(C) Setting of KES-FB SYSTEM data measurement program ver6.46WJ / friction SENS; H
・ SPEED: 0.5 mm / second ・ Frictional load: 25 g
・ Direction selection; WARP

  Table 1 shows the paint redispersibility evaluation, the scratch resistance evaluation of the coating film, and the tactile sensation evaluation. Table 1 also shows the average particle diameter, restoration rate, and compressive strength of the resin particles used in each paint.

From the above results, even when the average particle diameter of the resin particles is almost the same, in the compound of the general formula (I), n is 1 or 4, ethylene glycol dimethacrylate (Comparative Examples 1 and 2) or Resin particles obtained using tetraethylene glycol dimethacrylate (Comparative Examples 3 and 4), respectively, are tetradecaethylene glycol dimethacrylate (Examples 1 and 3 ) in which n is 14 or 9 in the compound of general formula (I). And 5 ) or nonaethylene glycol dimethacrylate (Examples 2 and 4 ), respectively, all showed a low value in the restoration rate and a high value in the compressive strength.

That is, in the compound of the general formula (I), the resin particles obtained in Examples 1 to 5 using a compound having a higher degree of polymerization of ethyleneoxy group used a compound having a lower degree of polymerization of ethyleneoxy group. A softer coating film was obtained from the resins obtained in Comparative Examples 1 to 4, and a coating liquid showing good redispersibility was obtained.
Moreover, the coating film produced with the coating material using the resin particle obtained in Examples 1-5 gave all favorable evaluation in scratch resistance and tactile evaluation.

Claims (6)

Formula (I):
_{CH 2 = C (CH 3)} -COO- (CH 2 CH 2 O) n -CO-C (CH 3) = CH 2
(Where n is an integer from 9 to 14 )
And a polymer of a mixture containing at least 10 to 50% by weight and 90 to 50% by weight of a crosslinkable monomer having a vinyl group at both ends of the molecule and (meth) acrylic acid ester, Resin particles having a restoration rate of 15% to 30%.   The resin particle according to claim 1, wherein n in the general formula (I) is 9 or 14.   The resin particles according to claim 1, wherein the resin particles are particles obtained by subjecting the mixture to aqueous suspension polymerization in the presence of a suspension stabilizer.   The resin particles include an inorganic powder adhered to a surface thereof, and the inorganic powder has an average particle diameter of 1/10000 to 1/100 of an average particle diameter of the resin particles, The resin particles according to claim 1, wherein 0.1 to 5% by weight of the inorganic powder and the resin particles are used.   The coating-film softening agent containing the resin particle as described in any one of Claims 1-4.   A matting agent for paint comprising the resin particles according to any one of claims 1 to 4.