Elastomeric composite particles, method for producing same, and method for producing elastomeric spherical particles

Abstract

Provided are: elastomeric composite particles containing elastomeric spherical particles having, as a constituent unit, a (co)polymer that is highly degradable when exposed to an external stimulus such as light; elastomeric spherical particles; and methods for producing elastomeric spherical particles and elastomeric composite particles.　The elastomeric composite particles have a polyorganosilsesquioxane or silica on the surface of elastomeric spherical particles which have a volume average particle diameter of 0.5-200 µm and which are crosslinked particles of a copolymer having a polyester structure and a polyether structure.

Description

Elastomer composite particles, their manufacturing method, and elastomer spherical particles

[0001] The present invention relates to elastomer composite particles, a method for producing the same, and a method for producing elastomer spherical particles.

[0002]

[0003] Conventionally, examples of raw rubbers used for rubber products include, and are frequently used, the following: [1] polymers whose repeating units are composed solely of conjugated diene units, such as butadiene rubber, isoprene rubber, chloroprene rubber, and natural rubber; [2] polymers whose repeating units essentially consist of conjugated diene units and aromatic vinyl units, such as styrene-butadiene copolymer rubber, styrene-isoprene copolymer rubber, and styrene-isoprene-butadiene copolymer rubber; [3] polymers whose repeating units essentially consist of conjugated diene units and α,β-unsaturated nitrile units, such as acrylonitrile-butadiene copolymer rubber; [4] polymers whose repeating units essentially consist of acrylate units, such as acrylic rubber; [5] polymers whose repeating units are composed of ethylene, an α-olefin having 3 to 12 carbon atoms, and optionally a non-conjugated polyene, such as ethylene-propylene rubber; and [6] polymers whose repeating units are composed of dimethylsiloxane units, such as silicone rubber.

[0003] Spherical elastomer (rubber) particles obtained from these raw rubber materials, especially those with an organic skeleton, are used primarily in electronic materials, including electronic devices, to improve various properties such as impact resistance, thermal shock resistance, and adhesion.

[0004] Meanwhile, silicone rubber spherical particles and powders have been proposed for use in a wide range of industrial fields, including, for example, their addition to synthetic resin materials (Patent Documents 1 and 2), synthetic rubber materials (Patent Document 3), and cosmetics (Patent Documents 4 to 7).

[0005] Silicone rubber spherical particles are blended and used, taking advantage of their flexibility, as a stress-reducing agent for organic resins such as epoxy resins. The difference in the thermal expansion coefficient between electronic components and organic resins such as epoxy resins can cause stress to be applied to the resin, resulting in cracks and breakage. The addition of silicone rubber spherical particles can prevent this.

[0006] Specifically, there have been proposed epoxy resins containing spherical particles of a cured polymer containing linear organopolysiloxane blocks (Patent Document 8), and epoxy resins containing spherical particles of silicone rubber whose surfaces are coated with polyorganosilsesquioxane (Patent Document 9).

[0007] Patent Document 10 also discloses a method for preparing silicone-containing rubber spherical particles by copolymerizing, in an emulsion system, a (meth)acrylic acid ester and a diorganopolysiloxane having an organic group containing a radically polymerizable functional group at one end. These organic rubber spherical particles are used to impart slip properties to thermoplastic resins.

[0008] Furthermore, organic crosslinked rubber spherical particles (Patent Document 11) have been proposed which are obtained by crosslinking a liquid composition comprising an organic compound having an aliphatic unsaturated bond and a silicon-containing organic compound having silicon-bonded hydrogen atoms through a hydrosilylation reaction, as they have excellent dispersibility in components such as various resins, paints, and rubbers, and are easy to handle.

[0009] Furthermore, silicone rubber spherical particles are used in a wide range of cosmetics and cosmetic materials, including makeup cosmetics such as foundations and primers, basic cosmetics such as creams and emulsions, and sunscreen cosmetics, for the purposes of imparting a soft feel, smoothness, and other sensations upon use to cosmetics, scattering light to create a natural finish, and making pores and wrinkles less visible.

[0010] For example, proposed cosmetics include those containing polymethylsilsesquioxane particles and powder (Patent Document 12), makeup cosmetics containing spherical silicone rubber particles and powder (Patent Document 13), and cosmetics containing silicone composite particles and powder in which silicone rubber spherical particles are coated with a polyorganosilsesquioxane resin (Patent Document 14). As described above, these silicone rubber spherical particles and composite particles in which silicone rubber spherical particles are coated with a polyorganosilsesquioxane resin can impart a soft feel, smoothness, and other usability sensations to cosmetics.

[0011] JP 63-12489 JP 6-55805 JP 2-102263 JP 8-12546 JP 8-12545 JP 4-17162 JP 4-66446 58-219218 JP 8-85753 JP 10-182987 JP 2001-40214 JP 63-297313 JP 8-12524 JP 9-20631

[0012] However, when these silicone rubber spherical particles that are blended into various resins, cosmetics, etc. are released or spilled into natural environments such as soil, land water, seawater, and the ocean, they are predicted to remain in the environment without being decomposed because they do not have a skeleton or units within their particle structure that possess or impart degradability. Furthermore, because these particles have a small particle size, recovery, etc. is extremely difficult, and it is currently unavoidable that they will end up in the ocean, etc.

[0013] In addition, plastics that have flowed into the ocean and microplastics that have been broken down and refined to millimeter to micrometer sizes have the ability to adsorb harmful substances and pathogens present in the environment. There are concerns that if marine organisms accidentally ingest these, they could have a negative impact on the ecosystem, and so there are beginning to be moves to regulate these microplastics.

[0014] Against this background, there is a growing demand for silicone or elastomer spherical particles that decompose in the environment after use and do not remain as particles (solid matter). In order for these elastomer spherical particles to decompose in the environment, the crosslinked structure that forms the particles must be cleaved and decomposed in the environment, but silicone rubber spherical particles are not degradable due to their structure.

[0015] The present invention has been made in view of the above circumstances, and aims to provide elastomer composite particles containing elastomeric spherical particles whose constituent units are (co)polymers that are highly degradable in natural environments, including soil, land water, and ocean / seawater, due to external stimuli such as light, heat, acids, and bases, or the action of microorganisms, fungi, etc. Another object of the present invention is to provide methods for producing elastomeric spherical particles and elastomer composite particles whose constituent units are (co)polymers that are highly degradable.

[0016] As a result of intensive research to achieve the above-mentioned object, the present inventors have found that elastomer composite particles having as core particles elastomer spherical particles, which are crosslinked particles of a copolymer having a specific polyester structure and a polyether structure, can solve the above-mentioned problems, and have thus completed the present invention.

[0017] Accordingly, the present invention provides the following elastomer composite particles, a method for producing elastomer spherical particles, and a method for producing elastomer composite particles. [1] Elastomer composite particles having a volume average particle size of 0.5 to 200 μm, each of which is a crosslinked particle of a copolymer having a polyester structure and a polyether structure, and which have polyorganosilsesquioxane or silica on the surface of the elastomer spherical particles. [2] Elastomer composite particles according to [1], wherein the copolymer is a polyester-polyether copolymer having at least two radically polymerizable unsaturated groups in one molecule. [3] Elastomer composite particles according to [2], wherein the copolymer is a polyester-polyether copolymer represented by the following general formula (1) or (2): (In general formula (1), R 1 each independently represents a divalent hydrocarbon group having 1 to 10 carbon atoms; R 2each independently represents a radically polymerizable functional group-containing organic group represented by the following general formula (3a), (3b), or (3c), where k is a number that satisfies 1≦k≦10, l is a number that satisfies 1≦l≦1,000, m is a number that satisfies 1≦m≦1,000, and n is a number that satisfies 1≦n≦100. 3 each independently represents a divalent hydrocarbon group having 1 to 10 carbon atoms; R 4 each independently represents a radically polymerizable functional group-containing organic group represented by the following general formula (4a) or (4b), each p independently represents a number that satisfies 1≦p≦10, each l independently represents a number that satisfies 1≦l≦1,000, each m independently represents a number that satisfies 1≦m≦1,000, and each q independently represents a number that satisfies 1≦q≦100. (In general formulas (3a), (3b), (3c), (4a) and (4b), R 5 each independently represents a divalent hydrocarbon group having 1 to 8 carbon atoms; R 6 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms.) [4]. The elastomer composite particles according to [2], wherein the copolymer is a polyester-polyether copolymer represented by the following general formula (5): (In general formula (5), R 1 each independently represents a divalent hydrocarbon group having 1 to 10 carbon atoms; R 2 each independently represents a radically polymerizable functional group-containing organic group represented by the following general formula (3a), (3b), or (3c), l is a number that satisfies 1≦l≦1,000, m is a number that satisfies 1≦m≦1,000, and each r is independently a number that satisfies 1≦r≦100. (In general formulas (3a), (3b) and (3c), R 5 each independently represents a divalent hydrocarbon group having 1 to 8 carbon atoms; R 6each independently represents a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms.) [5]. A method for producing elastomer spherical particles, comprising the following steps i) to iii): i) a step of stirring and suspending the following components (A), (B), (C), and (D) to prepare a suspension composition: (A) a copolymer having a polymerizable group and having a polyester structure and a polyether structure; (B) an aqueous phase component or an oil phase component in which component (A) is insoluble or poorly soluble; (C) a suspending agent; and (D) a polymerization initiator. ii) a step of radically polymerizing component (A) in the suspension composition obtained in step i) to obtain a dispersion of elastomer spherical particles; and iii) a step of washing and drying to remove the continuous phase (B) from the dispersion of elastomer spherical particles obtained in step ii) to obtain elastomer spherical particles. [6]. A method for producing elastomer composite particles according to any one of items [1] to [4], comprising the following step iv): iv) A step of adding the following component (I) to a liquid phase containing the following components (E), (F), (G), and (H), and hydrolyzing and polymerizing the component (I): (E) Elastomeric spherical particles produced by the method described in [5], which are crosslinked particles having a volume average particle size of 0.5 to 200 μm and containing structural units derived from a copolymer having a polyester structure and a polyether structure; (F) An alkaline substance; (G) One or more selected from a cationic surfactant and a cationic water-soluble polymer compound; (H) Water; and (I) A trialkoxysilane or a tetraalkoxysilane.

[0018] The elastomer composite particles of the present invention have a degradable polyester structure as a unit skeleton. The crosslinked structure of the particles is cleaved in the presence of moisture, making them degradable. In particular, particles containing a poly-ε-caprolactone structure, a microorganism-recognition skeleton, as the polyester structure within the particles are expected to be environmentally and biodegradable as elastomer spherical particles and elastomer composite particles. Therefore, the elastomer composite particles of the present invention are (biodegradable) particles and are expected to be used as materials that reduce environmental impact. Furthermore, because the elastomer composite particles of the present invention have low agglomeration and high dispersibility, they are expected to have an enhanced stress relaxation effect when blended with various resins. Furthermore, in cosmetic applications, the incorporation of the elastomer composite particles of the present invention is expected to enhance usability, such as a soft feel and smoothness, and to impart extensibility. The elastomer composite particles of the present invention can also be made hydrophilic by adjusting the coating (attachment) amount of silica microparticles attached to the surface, allowing them to be incorporated into aqueous cosmetics without the use of dispersants such as emulsifiers.

[0019] 1 is an electron microscope photograph of elastomer spherical particles obtained in Production Example 1. 2 is an electron microscope photograph of elastomer spherical particles obtained in Production Example 3. 3 is an electron microscope photograph (magnification x 1,000) of elastomer composite particles (silica-coated elastomer spherical particles) obtained in Example 3. 4 is an electron microscope photograph (magnification x 7,500) of elastomer composite particles (silica-coated elastomer spherical particles) obtained in Example 3.

[0020] The present invention will be described in detail below.

[0021] [Elastomer Composite Particles] The elastomer composite particles of the present invention have polyorganosilsesquioxane or silica on the surface of elastomer spherical particles, which are crosslinked particles of a copolymer having a polyester structure and a polyether structure. Preferably, the elastomer spherical particles have polyorganosilsesquioxane spherical fine particles or silica spherical fine particles attached to the particle surface.

[0022] The shape of the elastomer composite particles of the present invention is preferably spherical. In the present invention, "spherical" does not only refer to a true sphere, but also includes deformed ellipsoids with an average aspect ratio (length of longest axis / length of shortest axis) of typically 1 to 4, preferably 1 to 2, more preferably 1.0 to 1.6, and even more preferably 1.0 to 1.4. As described in the production method described below, when a copolymer having a polyester structure and a polyether structure is suspended and dispersed using a suspending agent and crosslinked, the resulting particles have a spherical shape. The shape of the elastomer composite particles can be confirmed, for example, by observation using an optical microscope or electron microscope. The aspect ratio is calculated by measuring the lengths of the longest and shortest axes of 50 randomly selected particles from a micrograph and averaging the results.

[0023] In the present invention, the volume average particle size of the elastomer composite particles is in the range of 0.5 to 200 μm, more preferably in the range of 1.0 to 50 μm. If the volume average particle size is larger than the above upper limit, the particles' smoothness and silkiness may decrease, resulting in a rough feeling and reduced light diffusion. Furthermore, if the volume average particle size is smaller than the above lower limit, the fluidity of the particles decreases and the tendency to aggregate increases, making it impossible to impart sufficient smoothness and light diffusion, which is undesirable. The volume average particle size of the elastomer composite particles of the present invention is a value measured as follows. Prior to measuring the volume average particle size, the particle sizes of 50 particles are randomly selected from a micrograph of the elastomer composite particles, and the average value is determined to be equal to or greater than 1 μm or less. A dispersion liquid is prepared by redispersing the elastomer composite particles in water using various surfactants, and if the result of the above determination is 1 μm or more, the volume average particle size is indicated as a value measured by an electrical resistance method, and if the result of the determination is less than 1 μm, the volume average particle size is indicated as a value measured by a laser diffraction / scattering method.

[0024] The rubber (elastomer) that is a component of the elastomer composite particles preferably does not exhibit tack or stickiness. The rubber hardness of the rubber (elastomer) that is a component of the elastomer composite particles, as measured using a Type A durometer as specified in JIS K6253, is preferably in the range of 5 to 90, more preferably 10 to 80. Furthermore, the rubber hardness of the rubber (elastomer) that is a component of the elastomer composite particles, as measured using an Asker Type C rubber hardness tester as specified in the Society of Rubber Industry Standards of Japan (SRIS), is preferably in the range of 5 to 90, more preferably 20 to 85, and even more preferably 40 to 85. If the rubber hardness measured is less than 5, the particles may become more cohesive and their dispersibility may decrease. Furthermore, if the rubber hardness is greater than 90, the soft feel may decrease, which is undesirable.

[0025] - Elastomer spherical particles that are crosslinked particles of a copolymer having a polyester structure and a polyether structure. The elastomer spherical particles in the elastomer composite particles of the present invention are preferably particles made of a polyester-polyether copolymer having at least two radically polymerizable unsaturated groups per molecule, i.e., crosslinked particles of a polyester-polyether copolymer having at least two radically polymerizable unsaturated groups per molecule. The aspect ratio of the elastomer spherical particles in the elastomer composite particles of the present invention is also defined in the same manner as above, and the average aspect ratio (length of longest axis / length of shortest axis) of the elastomer spherical particles is typically in the range of 1 to 4, preferably 1 to 2, more preferably 1.0 to 1.6, and even more preferably 1.0 to 1.4. The volume-average particle size of the elastomer spherical particles in the elastomer composite particles of the present invention is also defined in the same manner as above, and the volume-average particle size of the elastomer spherical particles is in the range of 0.5 to 200 μm, more preferably 1.0 to 50 μm.

[0026] The polyester-polyether copolymer having at least two radically polymerizable unsaturated groups in one molecule is preferably a copolymer represented by the following general formula (1) or (2). (In general formula (1), R 1 each independently represents a divalent hydrocarbon group having 1 to 10 carbon atoms; R 2 each independently represents a radically polymerizable functional group-containing organic group represented by the following general formula (3a), (3b), or (3c), where k is a number that satisfies 1≦k≦10, l is a number that satisfies 1≦l≦1,000, m is a number that satisfies 1≦m≦1,000, and n is a number that satisfies 1≦n≦100. 3 each independently represents a divalent hydrocarbon group having 1 to 10 carbon atoms; R 4 each independently represents a radically polymerizable functional group-containing organic group represented by the following general formula (4a) or (4b), each p independently represents a number that satisfies 1≦p≦10, each l independently represents a number that satisfies 1≦l≦1,000, each m independently represents a number that satisfies 1≦m≦1,000, and each q independently represents a number that satisfies 1≦q≦100. (In general formulas (3a), (3b), (3c), (4a) and (4b), R 5 each independently represents a divalent hydrocarbon group having 1 to 8 carbon atoms; R 6 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms.

[0027] R 1 Examples of alkylene groups include methylene, ethylene, propylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, and octamethylene groups, and preferably methylene, ethylene, trimethylene, and tetramethylene groups.

[0028] R 3 Examples of alkylene groups include methylene, ethylene, propylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, and octamethylene groups, and preferably methylene, ethylene, trimethylene, and tetramethylene groups.

[0029] R 2 represents a radically polymerizable functional group-containing organic group represented by general formula (3a), (3b), or (3c), and R 4represents a radical polymerizable functional group-containing organic group represented by general formula (4a) or (4b). In general formulas (3b), (3c), (4a), and (4b), R 5 Examples of R include alkylene groups such as methylene, ethylene, propylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, and octamethylene, and are preferably methylene, ethylene, trimethylene, or tetramethylene. 6 Examples of the radical polymerizable functional group-containing organic groups represented by general formulas (3a), (3b), (3c), (4a), and (4b) include a hydrogen atom, a methyl group, an ethyl group, a propyl group, or another alkyl group having 1 to 3 carbon atoms, and preferably a hydrogen atom or a methyl group. Specific examples of the radical polymerizable functional group-containing organic groups represented by general formulas (3a), (3b), (3c), (4a), and (4b) include residues derived from polymerizable monomers, and specific examples of the polymerizable monomers include hydroxyl group-containing (meth)acrylic acid esters, isocyanate group-containing (meth)acrylic acid esters, and (meth)acrylic acid chlorides.

[0030] Examples of hydroxyl group-containing (meth)acrylic acid esters include hydroxyalkyl esters of (meth)acrylic acid having 2 to 8 carbon atoms, such as hydroxyethyl (meth)acrylic acid ester and hydroxypropyl (meth)acrylic acid ester, and carboxy(meth)acrylates, such as carboxyethyl (meth)acrylate, (meth)acryloyloxyethyl succinate, and (meth)acryloyloxyethyl phthalate. Examples of isocyanate group-containing (meth)acrylic acid esters include isocyanate ethyl (meth)acrylic acid ester, isocyanate propyl (meth)acrylic acid ester, isocyanate butyl (meth)acrylic acid ester, and isocyanate hexyl (meth)acrylic acid ester. Examples of (meth)acrylic acid chlorides include acryloyl chloride, methacryloyl chloride, acryloyl bromide, and methacryloyl bromide.

[0031] The polyester structure (unit) of the polyester-polyether copolymer having at least two radically polymerizable unsaturated groups in one molecule is preferably an aliphatic polyester, which is considered to have or have high degradability. Examples of aliphatic polyesters include poly-ε-caprolactone, poly-β-propiolactone, γ-butyrolactone, polylactic acid, polyhydroxybutyrate, polyglycolic acid, polyethylene adipate, polyhydroxybutyric acid, polyethylene succinate, and polybutylene succinate. In particular, from the viewpoints of degradability and ease of handling, those having a poly-ε-caprolactone structure are preferred.

[0032] In general formula (1), k's each independently represent a number within the range of 1≦k≦10, and preferably a number within the range of 1≦k≦6. In general formula (2), p's each independently represent a number within the range of 1≦p≦10, and preferably a number within the range of 1≦p≦6.

[0033] In general formula (1), n ​​is independently a number satisfying 1≦n≦100, preferably a number satisfying 1≦n≦50, and more preferably a number satisfying 2≦n≦20. In general formula (2), q is independently a number satisfying 1≦q≦100, preferably a number satisfying 1≦q≦50, and more preferably a number satisfying 2≦q≦20. When the values ​​of n and q are greater than the upper limit values, the crystallinity increases due to the intramolecular / intermolecular interactions of the polymer caused by the ester structure (unit). Therefore, if the fluidity of the copolymer is too low, this may affect the handleability in the preparation step of the suspension composition described below.

[0034] In general formulas (1) and (2), l is a number within the range of 1≦l≦1,000, preferably 2≦l≦100. In general formulas (1) and (2), m is a number within the range of 1≦m≦1,000, preferably 10≦m≦500. If the value of l is greater than the upper limit, the crystallinity increases due to the intramolecular / intermolecular interactions of the polymer caused by the ethylene oxide structure (unit), which may reduce the fluidity of the copolymer. In this case, as described above, the handleability may be affected in the preparation process of the suspension composition described below, which is undesirable.

[0035] The polyester-polyether copolymer having at least two radically polymerizable unsaturated groups in one molecule is preferably a copolymer represented by the following general formula (5) or (6), from the viewpoints of ease of handling of raw materials and production. (In general formula (5), R 1 each independently represents a divalent hydrocarbon group having 1 to 10 carbon atoms; R 2 each independently represents a radically polymerizable functional group-containing organic group represented by general formula (3a), (3b) or (3c), l is a number of 1≦l≦1,000, m is a number of 1≦m≦1,000, and r is a number of 1≦r≦100. (In general formula (6), R 3 each independently represents a divalent hydrocarbon group having 1 to 10 carbon atoms; R 4 each independently represents a radically polymerizable functional group-containing organic group represented by general formula (4a) or (4b), l is a number that satisfies 1≦l≦1,000, m is a number that satisfies 1≦m≦1,000, and each s is independently a number that satisfies 1≦s≦100.

[0036] Methods for Producing Polyester-Polyether Copolymers Examples of methods for producing the polyester-polyether copolymers that constitute the elastomer composite particles of the present invention include a method in which various polyethers containing active hydrogen, such as polyethers having hydroxyl groups, carboxy-modified polyethers, and amino-modified polyethers, are used as starting materials and subjected to ring-opening polymerization of cyclic-ε-caprolactone, γ-butyrolactone, or the like to obtain poly-ε-caprolactone-modified polyethers and poly-γ-butyrolactone-modified polyethers, and then a polymerizable monomer having a radically polymerizable unsaturated group is introduced via an ester bond, ether bond, urethane bond, amide bond, or the like. From the viewpoint of reactivity during production, the terminal structure of the various polyethers is preferably a structure in which a reactive functional group is bonded to a primary carbon atom.

[0037] In the above-described production method, reaction conditions include, but are not limited to, the following: To 1.0 equivalent of an active hydrogen-containing polyether, such as a polyether or a carboxy-modified polyether, 3.0 to 4.0 equivalents (functional group equivalent ratio) of cyclic-ε-caprolactone are added, for example, and the reaction is carried out at 120°C for 4 to 6 hours in the presence of a conventional ring-opening polymerization catalyst, to obtain a poly-ε-caprolactone-modified polyether. Next, to 1.0 mole of hydroxyl groups in the obtained poly-ε-caprolactone-modified polyether, 1.0 to 1.25 moles (functional group equivalent ratio) of a (meth)acrylic acid chloride such as acrylic acid chloride or an isocyanate group-containing (meth)acrylic acid ester such as isocyanate ethyl (meth)acrylate is added, for example, and a reaction catalyst is added as necessary, followed by reaction at 40 to 100°C for 4 hours or longer. After the reaction, the crude product is quenched with alcohol or the like, and then by-products are removed by filtration, washing with water, and / or adsorption treatment. Finally, the solvent is distilled off to obtain an acrylic-modified poly-ε-caprolactone polyether (polyester-polyether copolymer).

[0038] When a polyether having a hydroxyl group is used as a starting material, examples of polyester-polyether copolymers include those represented by formulas (7a) and (7b) (only one side structure is shown due to the symmetrical structure).

[0039] In formulas (7a) and (7b), R 5 is a divalent hydrocarbon group having 1 to 8 carbon atoms, and R 6 is a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms. l, m, and r are 1≦l≦1,000, 1≦m≦1,000, and 1≦r≦30, and preferably 2≦l≦100, 10≦m≦500, and 2≦r≦10.

[0040] When a carboxy-modified polyether is used as a starting material, examples of polyester-polyether copolymers include those shown in formulas (8a) and (8b) (only one end is shown due to the symmetrical structure).

[0041] In formulas (8a) and (8b), R5 is a divalent hydrocarbon group having 1 to 8 carbon atoms, and R 6 is a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms. Furthermore, l, m, s, and t are 1≦l≦1,000, 1≦m≦1,000, 1≦s≦30, and 0≦t≦10, and preferably 2≦l≦100, 10≦m≦500, 2≦s≦10, and 1≦t≦10.

[0042] The catalyst used in the ring-opening polymerization of cyclic-ε-caprolactone may be any known catalyst, and is not limited thereto. Specific examples include organotitanium compounds such as tetramethoxytitanium, tetraethoxytitanium, tetra-n-propoxytitanium, and tetra-n-butoxytitanium; organotin compounds such as di-n-butyltin laurate, diisobutyltin oxide, and dibutyltin diacetate; acetates of magnesium, calcium, zinc, and the like; antimony oxide; stannous halides; and perchloric acid.

[0043] The amount of the ring-opening polymerization catalyst added may be in the range of 1 to 10,000 ppm, preferably 10 to 1,000 ppm, based on the ε-caprolactone monomer (cyclic ε-caprolactone).

[0044] As a method for introducing a polymerizable monomer having a radically polymerizable unsaturated group into the poly-ε-caprolactone-modified polyether, various catalysts may be used depending on the reaction substrate (reactive functional group) of the polymerizable monomer and the skeleton to be formed, and a conventionally known catalyst may be used.

[0045] When the reaction between a polymerizable monomer and a poly-ε-caprolactone-modified polyether is an esterification reaction, examples of the (esterification) catalyst used in the esterification reaction include alcoholates, carboxylates, or chelate compounds of titanium, zirconium, tin, aluminum, and zinc, as well as Lewis acid catalysts such as boron trifluoride and boron trifluoride etherate; acid catalysts such as hydrochloric acid, sulfuric acid, hydrogen bromide, acetic acid, trifluoroacetic acid, methanesulfonic acid, and p-toluenesulfonic acid; and amine catalysts such as pentamethyldiethylenetriamine (PMDETA), trimethyltriazacyclononane (TACN), triethylamine (TEA), 4-(N,N-dimethylamino)pyridine (DMAP), 1,4-diazabicyclo(2,2,2)octane (DABCO), and tetramethylethylenediamine (TMEDA). Among these, amine catalysts are preferred from the viewpoints of stability of the product obtained by the esterification reaction and economy.

[0046] When an amine catalyst is used, a dehydration condensation agent may be added to improve the reaction efficiency. Examples of the dehydration condensation agent that can be used include, but are not limited to, 1,1'-carbonyldiimidazole (CDI), N,N'-dicyclohexylcarbodiimide (DCC), N,N'-diisopropylcarbodiimide (DIC), 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC), 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC.HCl), and 1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3-oxide hexafluorophosphate (HATU).

[0047] When the reaction between a polymerizable monomer and a poly-ε-caprolactone-modified polyether is a urethanization reaction, examples of the catalyst used in the urethanization reaction include amines such as triethylamine, triethylenediamine, pentamethylenediethylenetriamine, N,N-dimethylethanolamine, 1,4-diazabicyclo(2,2,2)octane (DABCO), pyridine, and N,N,N',N'-tetramethyl-1,3-propanediamine (TMPDA); organic tin compounds such as di-n-butyltin laurate, diisobutyltin oxide, dibutyltin diacetate, dibutyltin dilaurate (DBTL), and dioctyltin dineodecanoate; tetramethoxytitanium, tetraethoxysilane, and the like. organic titanium compounds such as titanium dioxide, tetra-n-propoxy titanium, tetrabutoxy titanium, tetrakis(octyloxy) titanium, titanium acetylacetonate, titanium tetraacetylacetonate, dodecylbenzenesulfonic acid titanium compound, phosphate ester titanium complex, titanium triethanolaminate, titanium diisopropoxybis(ethylacetoacetate); organic zirconium compounds such as n-propyl zirconate, n-butyl zirconate, zirconium tetraacetylacetonate, zirconium dibutoxybis(ethylacetoacetate), zirconium octylate compound; and organic iron compounds such as tris(2,4-pentanedionato)iron(III).

[0048] The amount of catalyst added when introducing these polymerizable monomers having radically polymerizable unsaturated groups may be in the range of 1 to 10,000 ppm, preferably 10 to 1,000 ppm, based on the polymerizable monomer.

[0049] During the reaction, a polymerization inhibitor or antioxidant can be used to inhibit the polymerization reaction of the (meth)acrylate group during the reaction. Examples of the polymerization inhibitor or antioxidant include, but are not limited to, hydroquinone, p-methoxyphenol, 2,6-di-tert-butyl-p-cresol, 2,4-dimethyl-6-t-butylphenol, p-benzoquinone, dibutylhydroxytoluene, 2,5-dihydroxy-p-benzoquinone, and mequinol.

[0050] A method for producing a polyester-polyether copolymer includes, when a carboxy-modified polyether is used as a starting material, an esterification reaction with a poly-ε-caprolactone-modified (meth)acrylate represented by the following formula (9): Commercially available poly-ε-caprolactone-modified (meth)acrylates include PLACCEL FA2D, PLACCEL FA10L, PLACCEL FN2D, and PLACCEL FM4 (manufactured by Daicel Corporation). In general formula (9), R 7 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 3 carbon atoms, preferably a hydrogen atom or a methyl group, and v satisfies 1≦v≦50, preferably 1≦v≦30.

[0051] Examples of methods for producing the polyester-polyether copolymer include, but are not limited to, the following. To 1.0 mole of carboxy groups in the carboxy-modified polyether, 1.0 to 1.25 moles (functional group equivalent ratio) of poly-ε-caprolactone-modified (meth)acrylate (formula (9)) and 0.1 to 5.0 moles of an esterification catalyst are added and mixed, and the mixture is stirred at 15 to 150°C for 10 to 30 minutes. Optionally, 1.0 to 1.25 moles of a dehydration condensation agent are added thereto, and the mixture is reacted at 15 to 150°C for 4 to 20 hours. After the reaction, the crude product is filtered, washed with water, and / or subjected to an adsorption treatment to remove by-products, and finally the solvent is distilled off to obtain an acrylic-modified polyester(poly-ε-caprolactone)-polyether copolymer.

[0052] The obtained polyester-polyether copolymer having at least two radically polymerizable unsaturated groups in one molecule is preferably liquid, and the weight-average molecular weight (Mw.) measured by gel permeation chromatography (GPC) is preferably in the range of 100 to 100,000, more preferably 500 to 50,000. If the weight-average molecular weight is less than the lower limit mentioned above, the crosslink density of the elastomer in the obtained elastomer spherical / composite particles will be high, which is undesirable as it may result in poor degradability, whereas if it is greater than the upper limit mentioned above, the viscosity of the copolymer will be high, which may make it difficult to prepare the elastomer spherical particles.

[0053] In the filtration step, the crude reaction product may be diluted with a hydrophobic organic solvent to adjust its viscosity. The hydrophobic organic solvent to be used is not particularly limited, but toluene, hexane, ethyl acetate, etc. are preferred from the viewpoints of solubility and affinity for the polyester-polyether copolymer.

[0054] The adsorption treatment step is carried out for the purposes of removing hydrochlorides that cannot be completely removed by washing with water, and for the purposes of dehydration, decolorization, and deodorization. Any conventionally known adsorbent may be used, and a combination of several types may be used. Preferable adsorbents include desiccants such as magnesium sulfate and sodium sulfate, activated carbon, silica gel, and the Kyoward series (manufactured by Kyowa Chemical Industry Co., Ltd.). Using the copolymer having a polyester structure and a polyether structure produced by the above method, elastomer spherical particles can be produced, for example, by a method including the steps i) to iii) described below.

[0055] In the present invention, the polyorganosilsesquioxane on the surface of the elastomer spherical particles is R 7 SiO 3 / 2 It is a resin-like solid material in which units represented by are crosslinked in a three-dimensional network.

[0056] R in the above formula 7 is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 20 carbon atoms. 7Examples of the alkyl group include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, undecyl, dodecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, and icosyl; alkenyl groups such as vinyl and allyl; aryl groups such as phenyl, tolyl, and naphthyl; aralkyl groups such as benzyl and phenethyl; cycloalkyl groups such as cyclopentyl, cyclohexyl, and cycloheptyl; and hydrocarbon groups in which some or all of the hydrogen atoms bonded to carbon atoms of these groups have been substituted with atoms such as halogen atoms (fluorine, chlorine, bromine, and iodine atoms) and / or substituents such as amino, acryloyloxy, methacryloyloxy, epoxy, glycidoxy, mercapto, and carboxyl. In order to adhere polyorganosilsesquioxane to the surface of the elastomer spherical particles by the production method of the present invention described later, the above R 7 Preferably, 50 mol % or more of R are methyl groups, vinyl groups, or phenyl groups, 7 More preferably, 80 mol % or more of R are methyl groups, vinyl groups, or phenyl groups, 7 More preferably, 90 mol % or more of the groups are methyl groups, vinyl groups, or phenyl groups.

[0057] The polyorganosilsesquioxane may be selected from the group consisting of polyorganosilsesquioxane, ... 7 SiO 3 / 2 In addition to units, R 7 2SiO 2 / 2 Unit, R 7 3SiO 1 / 2 units, and SiO 4 / 2 In such polyorganosilsesquioxanes, at least one of R 7 SiO 3 / 2 The content of the units in the total siloxane units is preferably 70 to 100 mol %, more preferably 80 to 100 mol %.

[0058] -Silica In the present invention, the silica on the surface of the elastomer spherical particles is R 8 SiO 4 / 2 It is an inorganic solid in which units represented by the formula (I) are crosslinked in a three-dimensional network.

[0059] R in the above formula 8 is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms. 8 Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group.

[0060] Silica is obtained by the hydrolysis and polycondensation reaction of tetraalkoxysilane and is mainly composed of SiO2 units. In addition to the structure consisting of SiO2 units, silica may also contain alkoxy groups derived from the raw material tetraalkoxysilane and silanol groups that have not undergone condensation reaction.

[0061] In the present invention, the shape of the polyorganosilsesquioxane or silica is preferably spherical. The particle sizes of the polyorganosilsesquioxane and silica are each preferably 10 to 500 nm, more preferably 20 to 200 nm. If the particle sizes of the polyorganosilsesquioxane and silica are less than 10 nm, the light scattering properties of the resulting elastomer composite particles may be reduced. If the particle sizes of the polyorganosilsesquioxane and silica are greater than 500 nm, the resulting elastomer composite particles may lack a soft feel and have reduced light scattering properties. The polyorganosiloxane or silica may be attached to a portion of the particle surface of the elastomeric spherical particles, or may be attached over the entire particle surface, i.e., cover the entire particle surface; however, it is preferred that the polyorganosiloxane or silica be coated over the entire surface of the elastomeric spherical particles with almost no gaps. The particle size, shape, and adhesion density of polyorganosilsesquioxane and silica on the surface of the elastomer spherical particles can be confirmed by observing the particle surfaces of the obtained elastomer composite particles with an electron microscope. The particle sizes of polyorganosilsesquioxane and silica are calculated as the average value of the particle sizes of 50 randomly selected particles from an electron microscope photograph of the particle surfaces of the obtained elastomer composite particles.

[0062] In the elastomer composite particles of the present invention, the amount of polyorganosilsesquioxane or silica attached to the surface of the elastomer spherical particles is preferably 0.5 to 200 parts by mass, more preferably 1.0 to 50 parts by mass, per 100 parts by mass of the elastomer spherical particles. If the amount of polyorganosilsesquioxane or silica is less than the above-mentioned lower limit, the particles may become highly cohesive and poorly dispersible, resulting in reduced light scattering and a poor smooth feel. If the amount of polyorganosilsesquioxane or silica exceeds the above-mentioned upper limit, the elastomer composite particles may become less soft to the touch.

[0063] [Method for producing elastomeric spherical particles and elastomer composite particles] The method for producing elastomeric spherical particles of the present invention comprises the following steps i) to iii): i) a step of stirring and suspending the following components (A), (B), (C), and (D) to prepare a suspension composition: (A) a copolymer having a polymerizable group and having a polyester structure and a polyether structure; (B) an aqueous phase component or an oil phase component that is insoluble or poorly soluble in the component (A); (C) a suspending agent; and (D) a polymerization initiator. ii) a step of radically polymerizing the component (A) in the suspension composition obtained in the step i) to obtain a dispersion of elastomeric spherical particles. iii) a step of washing and drying to remove the continuous phase (B) from the dispersion of elastomeric spherical particles obtained in the step ii) to obtain elastomeric spherical particles.

[0064] The elastomer composite particles of the present invention can be produced, for example, by a method including the following step iv): iv) a step of adding the following component (I) to a liquid phase containing the following components (E), (F), (G), and (H) and subjecting component (I) to a hydrolysis and polymerization reaction; (E) elastomer spherical particles produced by the steps i) to ii) or i) to iii), which are crosslinked copolymer particles having a volume average particle size of 0.5 to 200 μm and having a polyester structure and a polyether structure; (F) an alkaline substance; (G) one or more members selected from a cationic surfactant and a cationic water-soluble polymer compound; (H) water; and (I) a trialkoxysilane or a tetraalkoxysilane. That is, the method for producing elastomer composite particles of the present invention can be broadly divided into two steps: steps i) to iii) for producing elastomer spherical particles and step iv) for composite-forming the elastomer spherical particles. Each step is described below. The aqueous dispersion of elastomer composite particles obtained in step iv) may be used as an aqueous dispersion as it is depending on the intended use, or may be subjected to a dehydration step for removing water and a powdering step to produce an elastomer composite particle powder, which may then be used for the intended use.

[0065] -Production Process of Elastomer Spherical Particles The elastomer spherical particles constituting the elastomer composite particles of the present invention are polymers (crosslinked particles) obtained by a radical polymerization reaction of the polyester-polyether copolymer, and are produced by a production method including the following steps i) to iii):

[0066] Step i) In step i), the following components (A), (B), (C), and (D) are stirred and suspended to prepare a suspension composition. The components used in step i) are as follows:

[0067] Component (A) is a copolymer having a polymerizable group and a polyester structure and a polyether structure, preferably a polyester-polyether copolymer having a radically polymerizable unsaturated group. The constituent units of the elastomer composite particles of the present invention are derived from a copolymer having a polyester structure and a polyether structure, and preferably a polyester-polyether copolymer having at least two radically polymerizable unsaturated groups in one molecule. Specific examples of component (A) include polyester-polyether copolymers represented by the general formula (1) or (2), and more preferably polyester-polyether copolymers represented by the general formula (5) or (6).

[0068] The content of component (A) in the suspension composition prepared in step i) is preferably 1.0 to 80 parts by mass per 100 parts by mass of the composition. If the amount of component (A) is less than the above lower limit, production efficiency may decrease, while if it is more than the above upper limit, suspension may be poor, making it difficult to obtain a dispersion of elastomer spherical particles, which is not preferred.

[0069] Component (B) is a component that forms a continuous phase in the suspension composition, and is an aqueous phase component or an oil phase component in which component (A) is insoluble or poorly soluble.

[0070] When component (B) is an aqueous phase component, specific examples of the water contained in the aqueous phase component include distilled water, ion-exchanged water, pure water, and ultrapure water.

[0071] The aqueous phase component may contain any additives as long as they do not impair the function of the continuous phase. Specific examples include, but are not limited to, preservatives, salts, pH adjusters, chelating agents, vitamins, amino acids, moisturizers, and antioxidants. To achieve a composition in which component (A) is insoluble or slightly soluble, the water content of the aqueous phase component is preferably 90 to 100% by mass.

[0072] When component (B) is an oil phase component, examples of the oil phase component include silicone oil, hydrocarbon oil, higher fatty acid, ester oil, liquid oil, etc., and these may be used alone or in appropriate combination of two or more types, but are not limited to these.

[0073] Examples of silicone oils include dimethylpolysiloxane, methylhydrogenpolysiloxane, methylphenylpolysiloxane, octamethylsiloxane, decamethyltetrasiloxane, decamethylcyclopentasiloxane, hexamethylcyclotrisiloxane, and octamethylcyclotetrasiloxane.

[0074] Examples of hydrocarbon oils include liquid paraffin, α-olefin oligomer, isododecane, isohexadecane, squalane, ozokerite, squalene, ceresin, paraffin, isoparaffin, paraffin wax, polyethylene wax, polyethylene-polypropylene wax, pristane, polyisobutylene, petrolatum, and microcrystalline wax.

[0075] Examples of higher fatty acids include lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, undecylenic acid, oleic acid, linoleic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), isostearic acid, and 12-hydroxystearic acid.

[0076] Examples of ester oils include isopropyl myristate, cetyl octanoate, octyldodecyl myristate, isopropyl palmitate, butyl stearate, hexyl laurate, myristyl myristate, decyl oleate, hexyldecyl dimethyloctanoate, cetyl lactate, myristyl lactate, lanolin acetate, isocetyl stearate, isocetyl isostearate, isononyl isononanoate, cholesteryl 12-hydroxystearate, ethylene glycol di-2-ethylhexanoate, dipentaerythritol fatty acid esters, N-alkyl glycol monoisostearate, neopentyl glycol dicaprate, diisostearyl malate, glycerin di-2-heptylundecanoate, trimethylolpropane tri-2-ethylhexanoate, trimethylolpropane triisostearate, penta-2-ethylhexanoate, Erythritol, glycerin tri-2-ethylhexanoate, glycerin trioctanoate, glycerin triisopalmitate, trimethylolpropane triisostearate, cetyl 2-ethylhexanoate, 2-ethylhexyl palmitate, glycerin trimyristate, tri-2-heptylundecanoic acid glyceride, castor oil fatty acid methyl ester, oleyl oleate, acetoglyceride, 2-hexyl palmitate butylundecyl, diisobutyl adipate, N-lauroyl-L-glutamic acid 2-octyldodecyl ester, di-2-heptylundecyl adipate, ethyl laurate, di-2-ethylhexyl sebacate, 2-hexyldecyl myristate, 2-hexyldecyl palmitate, 2-hexyldecyl adipate, diisopropyl sebacate, 2-ethylhexyl succinate, triethyl citrate, and the like.

[0077] Examples of liquid oils and fats include avocado oil, camellia oil, turtle oil, macadamia nut oil, corn oil, mink oil, olive oil, rapeseed oil, egg yolk oil, sesame oil, persic oil, wheat germ oil, camellia oil, castor oil, linseed oil, safflower oil, cottonseed oil, perilla oil, soybean oil, peanut oil, tea seed oil, Japanese kaya oil, rice bran oil, Chinese tung oil, Japanese tung oil, jojoba oil, germ oil, and triglycerin.

[0078] Component (B) has a kinematic viscosity of 100,000 mm at 25°C. 2 / s or less, and more preferably 10,000 mm 2 If the kinematic viscosity is greater than the above upper limit, suspension in step i) becomes difficult, and it may become difficult to obtain a suspension composition and elastomer spherical particles having a narrow particle size distribution.

[0079] Examples of the suspending agent of component (C) include conventionally known water-soluble polymer compounds such as natural polymer compounds, semi-synthetic polymer compounds, and synthetic polymer compounds, or polymer compounds used as thickeners. These may be used alone or in appropriate combination of two or more.

[0080] Examples of natural polymeric compounds include xanthan gum, cellulose, tamarind gum, tamarind seed gum, locust bean gum, gellan gum, HM pectin, carrageenan, guar gum, amaryllis seed gum, gum arabic, pullulan, agarose, agaropectin, alginic acid, karaya gum, succinoglycan, starch, dextrin, gelatin, and casein.

[0081] Examples of semi-synthetic polymer compounds include methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropylmethyl cellulose, carboxymethyl cellulose, cationized xanthan gum, LM pectin (acid-treated / alkali-treated), cationized guar gum, alginate, soluble starch, and cellulose nanofiber.

[0082] Examples of synthetic polymer compounds include polyvinyl alcohol, polyvinyl methyl ether, polyvinylpyrrolidone, carboxyvinyl polymer, polyacrylic acid, sodium polyacrylate, ammonium polyacrylate, polyacrylic acid amide, polyethylene glycol, polypropylene glycol, and polyethylene-polypropylene glycol.

[0083] As component (C), xanthan gum, tamarind gum, carrageenan, guar gum, gum arabic, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropylmethyl cellulose, carboxymethyl cellulose, cationized xanthan gum, cationized guar gum, polyvinyl alcohol, and polyvinylpyrrolidone are preferred, since a small amount of component (C) is sufficient to suspend component (A) and to obtain fine elastomeric spherical particles.

[0084] The amount of component (C) added is preferably 0.01 to 25 parts by mass, more preferably 0.05 to 15 parts by mass, per 100 parts by mass of the suspension composition. Addition amounts less than the lower limit mentioned above are undesirable, as they may result in poor emulsification or inability to obtain fine elastomeric spherical particles. Addition amounts greater than the upper limit mentioned above are undesirable, as they may result in a significant increase in the viscosity of the composition, making it impossible to obtain fine elastomeric spherical particles and resulting in insufficient particle dispersibility.

[0085] The polymerization initiator of component (D) may be a conventionally known radical polymerization initiator. In the presence of the polymerization initiator, an external stimulus such as heating, light irradiation, or UV irradiation is applied to generate radicals, which can cause reaction and curing (crosslinking).

[0086] Specific examples of the polymerization initiator (D) that can be used include peroxides, azo initiators, photoinitiators, and redox initiators that combine an oxidizing agent and a reducing agent.

[0087] Examples of peroxides include benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, o-methylbenzoyl peroxide, p-methylbenzoyl peroxide, 2,4-dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, di-t-butyl peroxide, t-butyl perbenzoate, hydrogen peroxide, etc. Perchlorates such as potassium perchlorate and sodium perchlorate may also be used.

[0088] Examples of azo initiators include 2,2'-azobis-isobutyronitrile, 2,2'-azobis-(2-methylbutyronitrile), 2,2'-azobis-(2,4-dimethylvaleronitrile), dimethyl 2,2'-azobis-(2-methylpropionate), dimethyl 2,2'-azobis-isobutyrate, t-butylperoxy-2-ethylhexanoate, and 2,2-azobis-(2-aminodipropane) dihydrochloride.

[0089] Examples of photoinitiators include 2,2-diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy-cyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropan-1-one, phenyl glyoxylic acid methyl ester, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, (2,4,6-trimethylbenzoyl)-diphenylphosphine oxide, and the like. Benzoin alkyl ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether can also be used.

[0090] Examples of redox initiators include a combination of ferrous sulfate, sodium pyrophosphate, glucose, and hydroperoxide, and a combination of ferrous sulfate, disodium ethylenediaminetetraacetic acid, Rongalite, and hydroperoxide. These redox initiators may also be used in combination with azo initiators or photoinitiators.

[0091] As the polymerization initiator, peroxides, azo-based initiators, and photoinitiators used in a heating method or a light irradiation method are preferred from the viewpoints of stability during the (radical) polymerization reaction of the suspension composition, ease of handling, and the like.

[0092] The amount of polymerization initiator added is preferably in the range of 0.01 to 5.0 parts by mass per 100 parts by mass of component (A). If the amount of polymerization initiator added is less than the above lower limit, curing (crosslinking) may be poor, while if it is more than the above upper limit, contamination from reaction residues may occur, resulting in odors, bleeding, and the like, which is undesirable.

[0093]

[0033] In the method for producing elastomer composite particles of the present invention, when preparing the suspension composition in step i), various additives may be blended as necessary in addition to the components (A), (B), (C), and (D). Examples of additives include thickeners, pH adjusters, preservatives, antioxidants, and polymerization inhibitors. These additives may be used singly or in appropriate combinations of two or more, in appropriate amounts within a range that does not impair the effects of the present invention.

[0094] The order of adding and mixing the components in step i) is not particularly limited, but for example, the suspension composition may be prepared by previously mixing component (A) and component (D) and then adding component (B) and component (C), or the suspension composition may be prepared from component (A), component (B), and component (C) and then component (D) is added. Furthermore, after preparing a suspension composition from component (A), component (B), component (C), and component (D), component (B) may be further added to dilute the composition to a desired concentration before subjecting it to step ii).

[0095] Furthermore, when the polyester-polyether copolymer having a radically polymerizable unsaturated group as component (A) has a cloud point (when the solubility of component (A) rapidly decreases and phase separation occurs at a certain temperature upon heating), or when the component (A) is temperature-dependent, the suspension composition in step i) may be prepared at a temperature appropriate for the temperature characteristics of component (A), for example, by stirring and suspending the component under heating. The temperature conditions for heating and heating are, for example, 100°C or lower, preferably 30 to 90°C, and more preferably 40 to 70°C. When the continuous phase is an aqueous phase component, a temperature higher than the upper limit mentioned above during heating and heating is undesirable because of the risk of water evaporation and bumping.

[0096] In preparing the suspension composition in step i), a conventionally known emulsifying disperser may be used. Examples of common emulsifying dispersers include a high-speed rotary shear type agitator such as a homomixer, a high-speed centrifugal radial type agitator such as a homodisper, a combination mix emulsifying agitator combining a homomixer and a homodisper, a mixing / emulsifying agitator (adihomomomixer) combining a homomixer or a homodisper and an anchor mixer, a high-pressure jet type emulsifying disperser such as a homogenizer, a colloid mill, an ultrasonic emulsifier, and a propeller agitator.

[0097] Step ii) Step ii) is a step of reacting and curing (crosslinking) the component (A) in the suspension composition prepared in step i) by (radical) polymerization to obtain a dispersion of elastomer spherical particles.

[0098] In step ii), the polymerization reaction conditions can be appropriately determined depending on the type of polymerization initiator (D). For example, when a peroxide or azo-based initiator is used, a heating method in which the reaction is carried out at a temperature of 30 to 80°C for 10 to 24 hours can be used, and when a redox-based initiator is used, a redox method in which the reaction is carried out at a temperature of 30 to 70°C for 2 to 24 hours can be used. When a photoinitiator is used, a photoirradiation method in which the reaction is carried out under light irradiation can be used, and the light source and wavelength range used for light or UV irradiation may be any of those known in the art.

[0099] Step iii) Step iii) is a step of obtaining elastomer spherical particles by washing and drying to remove the continuous phase component (B) from the dispersion of elastomer spherical particles obtained in step ii).

[0100] When the continuous phase (dispersion medium) of component (B) is an aqueous phase component, specific methods for step iii) include concentrating the dispersion by methods such as thermal dehydration, (pressure) filtration, centrifugation, and decantation, followed by a water washing operation, if necessary, by adding pure water or the like. Finally, examples include a method of heat drying under normal pressure or reduced pressure, a method of spraying the dispersion into a heated air stream and heat drying (spray drying), a method of heat drying using a fluid heat medium, and a freeze-drying method in which the dispersion is solidified, then reduced pressure is applied, and the dispersion medium is removed, thereby obtaining elastomeric spherical particles. Note that if the elastomeric spherical particles obtained by washing and drying to remove the dispersion medium are aggregated, they may be crushed using a mortar, ball mill, jet mill, etc.

[0101] When the continuous phase (dispersion medium) of component (B) is an oil phase component, specific methods for step iii) include adding a hydrophobic organic solvent to a dispersion of elastomer spherical particles, stirring for a certain period of time, and then filtering under pressure to wash and remove component (B) and replace the solvent. Repeating this washing procedure multiple times can thoroughly remove component (B) and replace the solvent. Examples of hydrophobic organic solvents that can be used in this process include toluene and hexane. Finally, elastomer spherical particles can be obtained by methods such as heat drying under atmospheric or reduced pressure, spray drying in which the dispersion is sprayed into a heated air stream and then heat-dried (spray drying), heat drying using a fluidized heat medium, or freeze-drying in which the dispersion is solidified, then decompressed, and the dispersion medium is removed. The elastomer spherical particles produced by the method comprising steps i) to iii) above have a volume-average particle size in the range of 0.5 to 200 μm, and more preferably are fine particles in the range of 1.0 to 50 μm. Therefore, the elastomer spherical particles obtained by the method for producing elastomer spherical particles of the present invention can be particularly suitably used for producing the elastomer composite particles of the present invention.

[0102] - Production process of elastomer composite particles (resin or silica-coated elastomer spherical particles) Step iv) Step iv) is a process in which the following component (I) is added to a liquid phase containing the following components (E), (F), (G), and (H), and component (I) is subjected to a hydrolysis and polymerization reaction.

[0103] The elastomer spherical particles of component (E) are the elastomer spherical particles obtained in the above-described steps i) to ii) or i) to iii). When component (B) used in step i) is an aqueous phase component, the aqueous dispersion of elastomer spherical particles obtained in steps i) and ii) may be subjected to step iv) as a mixture of component (E) and component (H) without going through step iii).

[0104] The amount of the elastomer spherical particles (E) is preferably 1.0 to 150 parts by mass, and more preferably 3.0 to 70 parts by mass, per 100 parts by mass of water (H) in the liquid phase containing components (E) to (H). If the amount of component (E) is less than the above lower limit, the production efficiency of the desired elastomer composite particles may decrease, while if it is more than the above upper limit, it becomes difficult to coat the surfaces of the elastomer spherical particles with polyorganosilsesquioxane or silica, which may cause aggregation or fusion of the particles, which is undesirable.

[0105] The alkaline substance (F) acts as a catalyst for the hydrolysis and polycondensation reaction of trialkoxysilane or tetraalkoxysilane. The alkaline substances may be used alone or in appropriate combination of two or more.

[0106] The alkaline substance is not particularly limited, and examples thereof include alkali metal hydroxides such as potassium hydroxide, sodium hydroxide, and lithium hydroxide; alkaline earth metal hydroxides such as calcium hydroxide and barium hydroxide; alkali metal carbonates such as potassium carbonate and sodium carbonate; ammonia; tetraalkylammonium hydroxides such as tetramethylammonium hydroxide and tetraethylammonium hydroxide; and amines such as monomethylamine, monoethylamine, monopropylamine, monobutylamine, monopentylamine, dimethylamine, diethylamine, trimethylamine, triethanolamine, and ethylenediamine. These alkaline substances may be used alone or in appropriate combination of two or more.

[0107] The most preferred alkaline substance is ammonia, since it can be easily removed from the powder of the elastomer composite particles obtained by volatilization. As the ammonia, commercially available aqueous ammonia solutions of various concentrations may be used.

[0108] The amount of alkaline substance (F) added is preferably an amount that results in a liquid phase containing components (E) to (H) with a pH of 9.0 to 13.0 at 25° C., more preferably an amount that results in a pH in the range of 10.0 to 12.0. Adding an amount that results in a pH of 9.0 to 13.0 allows the hydrolysis and polycondensation reaction of the trialkoxysilane or tetraalkoxysilane to proceed satisfactorily, and the surfaces of the elastomer spherical particles to be sufficiently coated with resin or silica.

[0109] (G) Cationic surfactants and cationic water-soluble polymer compounds have the effect of accelerating the condensation reaction of hydrolyzed trialkoxysilanes or tetraalkoxysilanes to produce resin or silica. They also have the effect of adsorbing the produced resin or silica onto the surfaces of the elastomer spherical particles. The cationic surfactants and cationic water-soluble polymer compounds can be used alone or in appropriate combinations of two or more.

[0110] Examples of cationic surfactants include alkyltrimethylammonium salts, dialkyldimethylammonium salts, polyoxyethylenealkyldimethylammonium salts, dipolyoxyethylenealkylmethylammonium salts, tripolyoxyethylenealkylammonium salts, alkylbenzyldimethylammonium salts, alkylpyridinium salts, monoalkylamine salts, and monoalkylamidoamine salts.

[0111] Examples of the cationic water-soluble polymer compound include polymers of dimethyldiallylammonium chloride, polymers of vinylimidazoline, polymers of methylvinylimidazolium chloride, polymers of ethyl acrylate trimethylammonium chloride, polymers of ethyl methacrylate trimethylammonium chloride, polymers of acrylamidopropyl trimethylammonium chloride, polymers of methacrylamidopropyl trimethylammonium chloride, epichlorohydrin / dimethylamine polymers, polymers of ethyleneimine, quaternized polymers of ethyleneimine, polymers of allylamine hydrochloride, polylysine, cationic starch, cationized cellulose, chitosan, copolymers of these with monomers having a nonionic group or an anionic group, and derivatives thereof.

[0112] As component (G), alkyltrimethylammonium salts of cationic surfactants are preferred, and among these, lauryltrimethylammonium salts and cetyltrimethylammonium salts are more preferred.

[0113] The amount of cationic surfactant and cationic water-soluble polymer compound added is preferably 0.01 to 2.0 parts by mass, more preferably 0.1 to 1.0 part by mass, per 100 parts by mass of water in the liquid phase containing (E) to (H). If the amount of component (G) added is less than the above lower limit, there is a risk of resin or silica not being coated on the surface of the elastomeric spherical particles, and if the amount added is more than the above upper limit, there is also a risk of resin or silica not being coated on the surface of the elastomeric spherical particles.

[0114] The water (H) is not particularly limited, and may be, for example, purified water, ion-exchanged water, pure water, or the like. When the component (B) is an aqueous phase component and the aqueous dispersion of elastomer spherical particles obtained in the step ii) is subjected to the step iv) without going through the step iii), the water (H) includes the water in the aqueous dispersion and water added as needed.

[0115] (I) The trialkoxysilane and tetraalkoxysilane are not particularly limited, and conventionally known ones may be used. From the viewpoint of reactivity, methyltrimethoxysilane, methyltriethoxysilane, tetramethoxysilane, and tetraethoxysilane are preferred, and methyltrimethoxysilane and tetramethoxysilane are more preferred. The tetraalkoxysilane may be one in which some or all of the alkoxy groups are hydrolyzed, or one in which some of the alkoxy groups are condensed.

[0116] The amount of trialkoxysilane added is preferably such that the amount of polyorganosilsesquioxane is 1.0 to 50 parts by mass, more preferably 2 to 25 parts by mass, per 100 parts by mass of the elastomer spherical particles (E).The amount of tetraalkoxysilane added is preferably such that the amount of silica is 0.5 to 200 parts by mass, more preferably 1.0 to 50 parts by mass, per 100 parts by mass of the elastomer spherical particles (E).

[0117] Hydrolysis and Polycondensation Reaction: (I) trialkoxysilane or tetraalkoxysilane is added to a liquid phase containing (E) to (H), and these are subjected to a hydrolysis and polycondensation reaction. Specifically, (I) trialkoxysilane or tetraalkoxysilane is added to an aqueous dispersion in which (E) elastomer spherical particles are dispersed in (H) water and (F) an alkaline substance, (G) one or more selected from cationic surfactants and cationic water-soluble polymer compounds are dissolved, and hydrolysis and polycondensation are carried out. Through the hydrolysis and polycondensation, polyorganosilsesquioxane or silica is attached to the surface of the elastomer spherical particles as a condensate of the trialkoxysilane or tetraalkoxysilane, thereby coating the surfaces of the elastomer spherical particles with polyorganosilsesquioxane or silica.

[0118] The trialkoxysilane and tetraalkoxysilane are preferably added under stirring using a conventional stirrer such as a propeller blade or flat blade. They may be added all at once, but it is preferable to add them over a period of time. The dropwise addition time is preferably in the range of 1 minute to 6 hours, more preferably 10 minutes to 3 hours.

[0119] The temperature of the liquid phase at this time is preferably 0 to 60°C, more preferably 0 to 40°C. If the temperature is within the above range, the polyorganosilsesquioxane or silica can be successfully attached to and coated on the surfaces of the elastomer spherical particles in the liquid phase. Stirring is continued after the addition of the trialkoxysilane or tetraalkoxysilane until the hydrolysis and polycondensation reactions are complete. To complete the hydrolysis and polycondensation reactions, the reaction may be carried out at room temperature or under heating at about 40 to 100°C, and an alkaline substance may also be added as appropriate.

[0120] Dehydration Step / Powdering Step After the hydrolysis / polycondensation reaction in step iv), water is optionally removed from the resulting aqueous dispersion of the elastomer composite particles of the present invention. Water removal can be achieved by heating the aqueous dispersion after the reaction under normal pressure or reduced pressure. Specific examples include a method of heat drying under normal pressure or reduced pressure, a method of spraying the dispersion into a heated air stream and heat drying (spray drying), a method of heat drying using a fluidized heat medium, and a freeze-drying method in which the dispersion is solidified, then reduced pressure is applied, and the dispersion medium is removed. This method yields elastomer composite particles. As a pretreatment step for this operation, the dispersion may be concentrated by a method such as heat dehydration, filtration, centrifugation, or decantation, and the aqueous dispersion may be washed with water or alcohol, if necessary.

[0121] If the powder of elastomer composite particles obtained by removing water from the aqueous dispersion after the reaction is aggregated, it may be pulverized using a pulverizer such as a jet mill, a ball mill, or a hammer mill.

[0122] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following examples, unless otherwise specified, "%" indicating concentration and content refers to "% by mass" and "parts" refers to "parts by mass." The kinematic viscosity indicates a value measured at 25°C. In the following examples, the volume average particle size and aspect ratio of the elastomer spherical particles and elastomer composite particles indicate values ​​measured by the above-mentioned methods. The hardness of the cured rubber (elastomer) is a value measured in accordance with the Society of Rubber Science and Technology Standards of Japan (SRIS).

[0123] The molecular weight of a copolymer having a polyester structure and a polyether structure (a polyester-polyether copolymer having at least two radically polymerizable unsaturated groups in one molecule) is the weight-average molecular weight (Mw.) measured by GPC under the following conditions, using polystyrene as the standard. [Measurement conditions] Developing solvent: tetrahydrofuran (THF) Flow rate: 0.60 mL / min Detector: differential refractive index detector (RI) Column: TSK Guard column Super H-H, TSKgel Super HM-N, TSKgel Super H2500 (all manufactured by Tosoh Corporation) Column temperature: 40°C Sample injection volume: 50 μL (THF solution with a concentration of 0.5% by mass)

[0124] [Method for measuring and evaluating biodegradability] Biodegradability was measured using a method using activated sludge as a microbial (degradation) source in accordance with OECD Guidelines for the Testing of Chemicals, No. 301F, July 17, 1992, "Ready Biodegradability: MANOMETRIC RESPIROMETRY TEST," and evaluated based on the degree of biodegradability. Activated sludge used was from a municipal sewage treatment plant, and the suspended solids concentration was 2,400 mg / L. Sodium benzoate was used as a reference (control) substance. The degree of biodegradation was measured by measuring the amount of oxygen consumed (biochemical oxygen consumption (BOD)) in a closed system in an incubator using a BOD meter, and calculating the degree of biodegradation according to the following formula: Biodegradation (%) = BOD - B / TOD x 100 BOD: Biochemical oxygen consumption of the test suspension or operation control (measured value: mg) B: Average biochemical oxygen consumption of the plant-source blank (measured value: mg) TOD: Theoretical oxygen consumption required for complete oxidation of the test substance or sodium benzoate (calculated value: mg)

[0125] Synthesis Example 1 of Acrylic-Modified Poly-ε-Caprolactone / Polyether Copolymer 1 A 2-L separable flask equipped with a stirrer, thermometer, condenser, and dropping funnel was charged with 500 g of primary-terminated EO (ethylene oxide) / PO (propylene oxide) polyether (molecular weight: approximately 2,000, OH group equivalent: 0.09-0.10 mol / 100 g), 183.6 g of ε-caprolactone (molecular weight: 114.1), and 350 g of dehydrated toluene, and heated to 90° C. under a nitrogen flow. After reaching the target temperature, 0.68 g of tetra-n-butoxytitanium (molecular weight: 340.0) was added as a catalyst, and the mixture was aged at 120° C. for 4 to 6 hours. Next, the poly-ε-caprolactone / polyether copolymer obtained by the above operation was cooled to near room temperature, and then 60.7 g of triethylamine (molecular weight 101.2), 100 g of dehydrated toluene, and 0.22 g of dibutylhydroxytoluene (BHT) (molecular weight 220.4) as a polymerization inhibitor were added, and the mixture was stirred for a certain period of time to achieve uniform dissolution. Then, 49.7 g of acrylic acid chloride (molecular weight 90.5) was added dropwise using a dropping funnel, and after confirming the generation of heat, the mixture was aged for 4 hours at 60° C. The resulting crude product was pressure filtered, washed with an aqueous sodium chloride solution using a separatory funnel, centrifuged, and then magnesium sulfate, silica gel, activated carbon, etc. were added, and powder treatment was performed by shaking to adsorb and remove impurities. After removing the various powders by pressure filtration, 0.22 g of dibutylhydroxytoluene (BHT) was added again, and the solvent was then distilled off at 60 to 70°C and 50 mmHg or less, thereby obtaining an acrylic-modified poly-ε-caprolactone / polyether copolymer 1 (formula (11) below, weight-average molecular weight: 2,880).

[0126] [Synthesis of acrylic-modified poly-ε-caprolactone / polyether copolymer 2 - Synthesis Example 2] 300 g of the same primary-terminated EO / PO polyether as in Synthesis Example 1, 110.2 g of ε-caprolactone, and 200 g of dehydrated toluene were placed in a 1 L separable flask equipped with a stirrer, a thermometer, a condenser, and a dropping funnel, and heated to 90° C. under a nitrogen flow. After the target temperature was reached, 0.41 g of tetra-n-butoxytitanium was added as a catalyst, and the mixture was aged at 120° C. for 4 to 6 hours. Next, the poly-ε-caprolactone / polyether copolymer obtained by the above procedure was cooled to near room temperature, and then 100 g of dehydrated toluene, 0.96 g of dioctyltin dineodecanoate (molecular weight: 687.7) as a catalyst, and 0.12 g of dibutylhydroxytoluene (BHT) were added. The mixture was stirred for a certain period of time to achieve a uniform solution, and then 44.4 g of 2-isocyanatoethyl acrylate (molecular weight: 141.1) was added dropwise using a dropping funnel. After confirming the generation of heat, the mixture was aged at 60°C for 4 hours. The resulting crude product was cooled to below 40°C, and 0.8 g of ethanol was added to react with unreacted (residual) isocyanate groups, resulting in a quenching treatment. Next, magnesium sulfate, silica gel, activated carbon, etc. were added, and the mixture was subjected to powder treatment by shaking to adsorb and remove impurities. After removing the various powders by pressure filtration, 0.12 g of dibutylhydroxytoluene (BHT) was added again, and the solvent was then distilled off at 60 to 70°C and 50 mmHg or less, thereby obtaining an acrylic-modified poly-ε-caprolactone / polyether copolymer 2 (formula (12) below, weight-average molecular weight: 3,120).

[0127] Synthesis Example 3 of Acrylic-Modified Poly-ε-Caprolactone / Polyether Copolymer 3 A 1-L separable flask equipped with a stirrer, a thermometer, a condenser, and a dropping funnel was charged with 300 g of primary-terminated EO / PO polyether (molecular weight: approximately 2,600, OH group equivalent: 0.09 to 0.10 mol / 100 g), 115.2 g of ε-caprolactone, and 200 g of dehydrated toluene, and heated to 90° C. under a nitrogen flow. After reaching the target temperature, 0.42 g of tetra-n-butoxytitanium was added to the catalyst, and the mixture was aged at 120° C. for 4 to 6 hours. Next, the poly-ε-caprolactone / polyether copolymer obtained by the above procedure was cooled to near room temperature, and then 70 g of dehydrated toluene, 0.18 g of tris(2,4-pentanedionato)iron(III) (also known as iron(III) acetylacetonate, molecular weight: 353.2) as a catalyst, and 0.13 g of dibutylhydroxytoluene (BHT) were added, and the mixture was stirred for a certain period of time to achieve a uniform solution. Then, 46.4 g of 2-isocyanatoethyl acrylate was added dropwise using a dropping funnel, and after confirming heat generation, the mixture was aged for 4 hours at 60° C. The obtained crude product was subjected to post-treatment and purification steps in the same manner as in Synthesis Example 2 above, to obtain acrylic-modified poly-ε-caprolactone / polyether copolymer 3. The acrylic-modified poly-ε-caprolactone / polyether copolymer 3 had a structure of formula (12), where l≈18-21, m≈34-38, r≈3-4, and the weight average molecular weight was 4,870.

[0128] [Synthesis of acrylic-modified poly-ε-caprolactone / polyether copolymer 4 - Synthesis Example 4] 300 g of the same primary-terminated EO / PO polyether as in Synthesis Example 3, 115.2 g of ε-caprolactone, and 200 g of dehydrated toluene were placed in a 1 L separable flask equipped with a stirrer, a thermometer, a condenser, and a dropping funnel, and heated to 90° C. under a nitrogen flow. After the target temperature was reached, 0.42 g of tetra-n-butoxytitanium was added as a catalyst, and the mixture was aged at 120° C. for 4 to 6 hours. Next, the poly-ε-caprolactone / polyether copolymer obtained by the above procedure was cooled to near room temperature, and then 70 g of dehydrated toluene, 2.77 g of zirconium tetraacetylacetonate (molecular weight: 487.7) as a catalyst, and 0.13 g of dibutylhydroxytoluene (BHT) were added. The mixture was stirred for a certain period of time to achieve a uniform solution, and then 46.4 g of 2-isocyanatoethyl acrylate was added dropwise using a dropping funnel. After confirming the generation of heat, the mixture was aged at 60°C for 4 hours. The obtained crude product was subjected to post-treatment and purification steps similar to the method described in Synthesis Example 2 above, thereby obtaining acrylic-modified poly-ε-caprolactone / polyether copolymer 4. Acrylic-modified poly-ε-caprolactone / polyether copolymer 4 had a structure represented by formula (12), where l≈18-21, m≈34-38, and r≈3-4, and had a weight-average molecular weight of 4,990.

[0129] Synthesis Example 5 of Acrylic-Modified Poly-ε-Caprolactone / Polyether Copolymer 5 A 1 L separable flask equipped with a stirrer, a thermometer, a condenser, and a dropping funnel was charged with 300 g of primary-terminated EO / PO polyether (molecular weight: approximately 3,200, OH group equivalent: 0.062 mol / 100 g), 106.3 g of ε-caprolactone, and 200 g of dehydrated toluene, and heated to 90° C. under a nitrogen flow. After reaching the target temperature, 0.41 g of tetra-n-butoxytitanium was added as a catalyst, and the mixture was aged at 120° C. for 4 to 6 hours. Next, the poly-ε-caprolactone / polyether copolymer obtained by the above procedure was cooled to around room temperature, and then 70 g of dehydrated toluene, 1.01 g of dioctyltin dineodecanoate as a catalyst, and 0.13 g of dibutylhydroxytoluene (BHT) were added, and the mixture was stirred for a certain period of time to achieve a uniform solution. 28.4 g of 2-isocyanatoethyl acrylate was then added dropwise using a dropping funnel, and after confirming the generation of heat, the mixture was aged for 4 hours at 60° C. The obtained crude product was subjected to post-treatment and purification steps in the same manner as in the method described in Synthesis Example 2 above, to obtain acrylic-modified poly-ε-caprolactone / polyether copolymer 5 (formula (13), weight average molecular weight: 7,940).

[0130] Synthesis Example 6 of Acrylic-Modified Poly-ε-Caprolactone / Silicone Copolymer: 300 g of carboxy-modified silicone (molecular weight: approximately 1,200, COOH group equivalent: 0.19 mol / 100 g), 202.8 g of poly-ε-caprolactone monoacrylate (OH group equivalent: 0.29 mol / 100 g, molecular weight: 344.0), 200 g of dehydrated toluene, and 6.85 g of 4-dimethylaminopyridine (DMAP) (molecular weight: 122.2) were placed in a 1 L separable flask equipped with a stirrer, thermometer, condenser, and dropping funnel, and the mixture was stirred and mixed in an ice bath. Once sufficiently cooled, a solution of 168.9 g of N,N'-dicyclohexylcarbodiimide (DCC) (molecular weight: 206.3) dissolved in 173.6 g of dehydrated toluene was added using the dropping funnel, and the mixture was allowed to react and age at room temperature for 20 hours. After aging, the mixture was washed with 200 g of toluene and 300 g of 0.5 mol / L hydrochloric acid (to remove DMAP), and then washed with saturated aqueous sodium bicarbonate and 10% aqueous sodium chloride, in that order. After performing the above operations, magnesium sulfate, silica gel, activated carbon, and Kyoward 700 (Kyowa Chemical Industry Co., Ltd.) were added and the mixture was shaken to adsorb and remove impurities. After removing the various powders by pressure filtration, 0.09 g of dibutylhydroxytoluene (BHT) was added, and the solvent was distilled off at 60 to 70°C and 10 mmHg or less, yielding an acrylic-modified poly-ε-caprolactone / silicone copolymer (formula (14) below, weight-average molecular weight: 2,130).

[0131] [Production of Elastomeric Spherical Particles - Production Example 1] A 1 L container of an AdiHomomixer was charged with 250 g of a 2.6% aqueous solution of hydroxypropyl methylcellulose (trade name: Metrose 60SH-4,000, manufactured by Shin-Etsu Chemical Co., Ltd.), and while operating the Homomixer and Anchor Mixer, the mixture was stirred and mixed under heating at 55 to 60°C. At the same time, 100 g of the acrylic-modified poly-ε-caprolactone / polyether copolymer 4 from Synthesis Example 4 described above and 1.0 g of dimethyl 2,2'-azobis-(2-methylpropionate) (molecular weight: 230.3) were charged into a descup, and the mixture was premixed in a Disper Mixer and preheated to 60 to 65°C. Next, the premixed acrylic-modified poly-ε-caprolactone / polyether copolymer was added to a 1 L adihomomomixer containing a heated aqueous hydroxypropyl methylcellulose solution, and the mixture was stirred and suspended for 10 minutes or more at 4,500 rpm with the homomixer at a temperature of 55 to 60°C, yielding an O / W suspension composition. The resulting suspension composition was then stirred and aged for 8 hours at 70°C at 200 rpm using a paddle-type stirring impeller, after which 50 g of pure water was added and the mixture was further aged for 6 hours at 80°C at the same rotation speed, yielding a dispersion of elastomer spherical particles.

[0132] The shape of the elastomer spherical particles in the obtained dispersion was observed under an optical microscope and found to be spherical. The volume average particle size was measured using an electrical resistance particle size distribution measuring device (Multisizer 3, manufactured by Beckman Coulter, Inc.) and found to be 5 μm.

[0133] The obtained dispersion of elastomer spherical particles was filtered through a mesh filter (#100) to check for the presence of agglomerates. If agglomerates were found, they were removed, and then the continuous phase, pure water, was removed by solid-liquid separation through pressure filtration. The above washing and separation procedure was repeated three times with pure water to remove water. Note that if solid-liquid separation is not successful in the pressure filtration step, centrifugation may be used. Finally, the obtained concentrate of elastomer spherical particles was left to stand and dried for 8 hours or more to obtain the desired white to pale yellow powder of elastomer spherical particles.

[0134] The resulting elastomer spherical particle powder was observed using an electron microscope (Scanning Microscope S-4700, manufactured by Hitachi High-Technologies Corporation), and was confirmed to be spherical particles with a particle size of approximately 5 μm. The aspect ratio of the resulting elastomer spherical particles was 1.0. The resulting elastomer spherical particles were redispersed in water using polyoxyethylene lauryl ether as a surfactant, and the resulting dispersion was measured and evaluated using an electrical resistance method, confirming that the volume average particle size was 5 μm.

[0135] The hardness of the elastomer (rubber) constituting the elastomer spherical particles was measured as follows. 30 g of the synthesized acrylic-modified poly-ε-caprolactone / polyether copolymer 4 and 0.24 g of 2'-azobis-(2,4-dimethylvaleronitrile) (molecular weight: 248.4) were stirred and mixed, and poured into an aluminum petri dish to a thickness of 10 mm. After leaving the mixture in an air thermostatic chamber at 70°C for 1 to 2 hours, a flat rubber without stickiness (tack) was obtained. The rubber hardness of the obtained flat rubber was measured, and it was found to be 72 on an Asker C hardness scale and 55 on an Asker A hardness scale.

[0136] [Production of Elastomeric Spherical Particles - Production Example 2] Elastomeric spherical particles were produced in the same manner as in Production Example 1, except that 250 g of a 2.6% aqueous solution of hydroxypropyl methylcellulose was used instead of 173 g of a 3.8% aqueous solution. As a result, elastomer spherical particles with a volume average particle size of 2 μm were obtained.

[0137] [Production of Elastomeric Spherical Particles - Production Example 3] Elastomeric spherical particles were produced in the same manner as in Production Example 1, except that the hydroxypropyl methylcellulose (trade name: Metrose 60SH-4,000, manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead (trade name: Metrose 60SH-50, manufactured by Shin-Etsu Chemical Co., Ltd.). As a result, elastomer spherical particles with a volume average particle size of 11 μm were obtained.

[0138] [Production of Elastomeric Spherical Particles - Production Example 4] Elastomeric spherical particles were produced in the same manner as in Production Example 1, except that 250 g of a 5.2% aqueous solution of xanthan gum was used instead of 250 g of a 2.6% aqueous solution of hydroxypropyl methylcellulose (trade name: Metrose 60SH-4,000, manufactured by Shin-Etsu Chemical Co., Ltd.). As a result, elastomeric spherical particles having a volume average particle size of 20 μm were obtained.

[0139] [Production of Elastomer Composite Particles - Example 1] A 500 ml glass flask equipped with a paddle-type stirring blade was charged with 100 g of the 20% solids dispersion of elastomer spherical particles obtained in Production Example 1, 184.9 g of pure water, and 0.2 g of a 30% aqueous solution of lauryltrimethylammonium chloride. After adjusting the temperature of the aqueous dispersion to 5-10°C, 0.75 g of 5.0% aqueous ammonia was added. While maintaining the aqueous dispersion at 5-10°C, 11.2 g of tetramethoxysilane (an amount sufficient to provide 22.0 parts of silica after the hydrolysis and polycondensation reaction per 100 parts of elastomer spherical particles) was added dropwise over 15-30 minutes. The liquid temperature was maintained at 5-10°C during this period, and stirring was continued for 1 hour. The mixture was then heated to 55-60°C, and stirred and aged for 1 hour while maintaining the temperature, completing the hydrolysis and condensation reaction of the tetramethoxysilane.

[0140] A dispersion of elastomer spherical particles, in which tetramethoxysilane was hydrolyzed and condensed, was dehydrated to a water content of approximately 30% using a pressure filter. The dehydrated product was then transferred to a 1 L glass flask equipped with an anchor-type impeller stirrer, 500 g of water was added, and the mixture was stirred for 30 minutes, after which it was dehydrated by pressure filtration. This washing and dehydration procedure was repeated three times, and the resulting dehydrated product was dried in a hot air flow dryer at 105°C. The dried product was then crushed in a jet mill to obtain flowable particles.

[0141] Observation of the obtained particles under an electron microscope confirmed that the entire particle surface of the elastomer spherical particles was coated with spherical silica, and that silica-coated elastomer spherical particles (elastomer composite particles) were obtained. The aspect ratio of the silica-coated elastomer spherical particles (elastomer composite particles) obtained in Example 1 was 1.0.

[0142] The obtained silica-coated elastomer spherical particles (elastomer composite particles) were dispersed in water using a surfactant (polyoxyethylene lauryl ether), and the dispersion was measured using an electrical resistance particle size distribution analyzer (Multisizer 3, manufactured by Beckman Coulter, Inc.). As a result, it was confirmed that the particle size distribution was equivalent to that of the aqueous dispersion of the above-mentioned elastomer spherical particles, and that the volume average particle size was approximately 5 μm.

[0143] [Production of Elastomer Composite Particles - Example 2] Elastomer composite particles were produced in the same manner as in Example 1, except that the elastomer spherical particles of Production Example 2 were used instead of the elastomer spherical particles of Production Example 1. As a result, silica-coated elastomer spherical particles (elastomer composite particles) with a volume average particle size of about 2 μm were obtained, in which spherical silica was attached and coated over the entire particle surface of the elastomer spherical particles.

[0144] [Production of Elastomer Composite Particles - Example 3] Elastomer composite particles were produced in the same manner as in Example 1, except that the elastomer spherical particles of Production Example 3 were used instead of the elastomer spherical particles of Production Example 1. As a result, silica-coated elastomer spherical particles (elastomer composite particles) with a volume average particle size of about 11 μm were obtained, in which spherical silica was attached and coated over the entire particle surface of the elastomer spherical particles.

[0145] [Production of Elastomer Composite Particles - Example 4] Elastomer composite particles were produced in the same manner as in Example 1, except that the elastomer spherical particles of Production Example 4 were used instead of the elastomer spherical particles of Production Example 1. As a result, silica-coated elastomer spherical particles (elastomer composite particles) with a volume average particle size of about 20 μm were obtained, in which spherical silica was attached and coated over the entire particle surface of the elastomer spherical particles.

[0146] [Production of Elastomer Composite Particles - Example 5] A 500 ml glass flask equipped with a paddle-type stirring blade was charged with 100 g of the 20% solids dispersion of elastomer spherical particles obtained in Production Example 3, 184.9 g of pure water, and 0.2 g of a 30% aqueous solution of lauryltrimethylammonium chloride. After adjusting the temperature of the aqueous dispersion to 5-10°C, 0.84 g of 5.0% aqueous ammonia was added. While maintaining the aqueous dispersion at 5-10°C, 12.5 g of methyltrimethoxysilane (an amount sufficient to provide 22.0 parts of silane per 100 parts of elastomer spherical particles after the hydrolysis and polycondensation reaction) was added dropwise over 15-20 minutes. The temperature of the solution was maintained at 5-10°C during this period, and the mixture was stirred for 1 hour. The subsequent procedures were the same as in Example 1, yielding particles with good flowability.

[0147] Observation of the obtained particles under an electron microscope confirmed that the entire particle surface of the elastomer spherical particles was coated with spherical polyorganosilsesquioxane, and that resin (polyorganosilsesquioxane)-coated elastomer spherical particles (elastomer composite particles) were obtained. Furthermore, the aspect ratio of the resin (polyorganosilsesquioxane)-coated elastomer spherical particles (elastomer composite particles) obtained in Example 5 was 1.0.

[0148] The obtained resin (polyorganosilsesquioxane)-coated elastomer spherical particles (elastomer composite particles) were dispersed in water using a surfactant (polyoxyethylene lauryl ether), and the particle size distribution was measured using an electrical resistance particle size distribution analyzer (Multisizer 3, manufactured by Beckman Coulter, Inc.). As a result, it was confirmed that the particle size distribution was equivalent to that of the aqueous dispersion of the above-mentioned elastomer spherical particles, and the volume average particle size was approximately 11 μm.

[0149] [Production of Elastomer Composite Particles - Example 6] Elastomer composite particles were produced in the same manner as in Example 1, except that the amount of tetramethoxysilane added was changed from 11.2 g (an amount that would result in 22.0 parts of silica after the hydrolysis and polycondensation reaction per 100 parts of the elastomer spherical particles) to 5.6 g (an amount that would result in 11.0 parts of silica after the hydrolysis and polycondensation reaction per 100 parts of the elastomer spherical particles). As a result, silica-coated elastomer spherical particles (elastomer composite particles) with a volume average particle size of approximately 5 μm were obtained, in which spherical silica was attached to and coated over the entire particle surface of the elastomer spherical particles.

[0150] The particle sizes of the spherical silica or resin (polyorganosilsesquioxane) attached to or coated on the surfaces of the elastomer spherical particles obtained in each Example were as shown in the table below.

[0151] [Biodegradability Evaluation] In accordance with the above-mentioned evaluation method, the biodegradability of acrylic-modified poly-ε-caprolactone / polyether copolymer 1 was evaluated at an incubation temperature of 22±1°C for 60 days. As a result, the degree of biodegradation of acrylic-modified poly-ε-caprolactone / polyether copolymer 1 averaged 62% after 28 days and 73% after 60 days, satisfying the criterion of 60% biodegradation after 28 days, and was therefore judged to be a "readily biodegradable substance." Therefore, it is presumed that the elastomer spherical particles, which are crosslinked particles of acrylic-modified poly-ε-caprolactone / polyether copolymer 1, and the composite particles will eventually decompose without remaining as particles in the environment if they are used and then released directly into the ocean via land waters or the like.

[0152] The biodegradability of acrylic-modified poly-ε-caprolactone / polyether copolymers 2 to 4 was measured at an incubation temperature of 22±1°C for 60 days. As a result, the biodegradability of acrylic-modified poly-ε-caprolactone / polyether copolymers 2 to 4 averaged 40% after 28 days and 65% after 60 days, satisfying the criterion of 60% biodegradation after 60 days, and they were therefore judged to be "essentially biodegradable substances." Therefore, it is presumed that the crosslinked elastomer spherical particles and composite particles of acrylic-modified poly-ε-caprolactone / polyether copolymers 2 to 4 will eventually decompose without remaining as particles in the environment if they are used and then released directly into the ocean via land waters or the like.

[0153] The biodegradability of the acrylic-modified poly-ε-caprolactone / silicone copolymer was evaluated at an incubation temperature of 22±1°C for 28 days, and the biodegradability of the acrylic-modified poly-ε-caprolactone / silicone copolymer was measured. After 28 days, the average biodegradability remained at 26%, with no increase in biodegradability observed thereafter. Since the criterion of 60% biodegradability after 28 days was not met, it was determined to be "not a (readily) biodegradable substance."

[0154] Due to their characteristic structural composition, the elastomer composite particles (resin- or silica-coated elastomer spherical particles) of the present invention are expected to be particularly useful in cosmetics, etc. Furthermore, because the powder / particle skeleton contains a degradable polyester structure (particularly poly-ε-caprolactone) and a polyether structure, they are expected to exhibit and impart high biodegradability.

Claims

1. Elastomer composite particles having a volume average particle size of 0.5 to 200 μm, the particles being elastomer spherical particles which are crosslinked particles of a copolymer having a polyester structure and a polyether structure, and on the surface of which are provided polyorganosilsesquioxane or silica.

2. The elastomer composite particle according to claim 1, wherein the copolymer is a polyester-polyether copolymer having at least two radically polymerizable unsaturated groups in one molecule.

3. The elastomer composite particle according to claim 2, wherein the copolymer is a polyester-polyether copolymer represented by the following general formula (1) or (2): (In general formula (1), R 1 each independently represents a divalent hydrocarbon group having 1 to 10 carbon atoms; R 2 Each independently represents a radical polymerizable functional group-containing organic group represented by the following general formula (3a), (3b) or (3c), each k independently represents a number of 1≦k≦10, each l represents a number of 1≦l≦1,000, each m represents a number of 1≦m≦1,000, and each n independently represents a number of 1≦n≦100. 3 each independently represents a divalent hydrocarbon group having 1 to 10 carbon atoms; R 4 each independently represents a radically polymerizable functional group-containing organic group represented by the following general formula (4a) or (4b), each p is independently a number of 1≦p≦10, each l is a number of 1≦l≦1,000, each m is a number of 1≦m≦1,000, and each q is independently a number of 1≦q≦100. (In general formulas (3a), (3b), (3c), (4a) and (4b), R 5 each independently represents a divalent hydrocarbon group having 1 to 8 carbon atoms; R 6 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms.

4. The elastomer composite particle according to claim 2, wherein the copolymer is a polyester-polyether copolymer represented by the following general formula (5): (In general formula (5), R 1 each independently represents a divalent hydrocarbon group having 1 to 10 carbon atoms; R 2 each independently represents a radically polymerizable functional group-containing organic group represented by the following general formula (3a), (3b) or (3c), l is a number that satisfies 1≦l≦1,000, m is a number that satisfies 1≦m≦1,000, and each r is independently a number that satisfies 1≦r≦100. (In general formulas (3a), (3b) and (3c), R 5 each independently represents a divalent hydrocarbon group having 1 to 8 carbon atoms; R 6 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms.

5. A method for producing elastomeric spherical particles comprising the following steps i) to iii): i) a step of stirring and suspending the following (A), (B), (C) and (D) components to prepare a suspension composition: (A) a copolymer having a polymerizable group and a polyester structure and a polyether structure; (B) an aqueous phase component or an oil phase component in which the (A) component is insoluble or poorly soluble; (C) a suspending agent; and (D) a polymerization initiator. ii) a step of radically polymerizing the (A) component in the suspension composition obtained by the step i) to obtain a dispersion of elastomeric spherical particles. iii) a step of washing and drying to remove the continuous phase (B) from the dispersion of elastomeric spherical particles obtained by the step ii) to obtain elastomeric spherical particles.

6. A method for producing the elastomer composite particles according to any one of claims 1 to 4, comprising the following step iv): iv) a step of adding the following component (I) to a liquid phase containing the following components (E), (F), (G) and (H) and subjecting the component (I) to a hydrolysis / polymerization reaction: (E) Elastomer spherical particles produced by the method according to claim 5, which are crosslinked particles of a copolymer having a polyester structure and a polyether structure and have a volume average particle size of 0.5 to 200 μm; (F) an alkaline substance; (G) one or more members selected from cationic surfactants and cationic water-soluble polymer compounds; (H) water; and (I) a trialkoxysilane or a tetraalkoxysilane.

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