Copolymer, elastomer spherical particles, dispersion of elastomer spherical particles, and method for producing them

Abstract

Provided are: a copolymer that has high degradability by outside stimulation such as light and has a polyester structure and a polyether structure, preferably a polyester-polyether copolymer that has at least two radical polymerizable unsaturated groups per molecule; elastomer spherical particles having a structural unit derived from the copolymer; and a method for producing the elastomer spherical particles.　A copolymer that has a polyester structure and a polyether structure; and elastomer spherical particles having a volume-average grain diameter of 0.5-200 μm, the elastomer spherical particles being composed of a polymer having a structural unit derived from a copolymer that has a polyester structure and a polyether structure.

Description

[Technical Field]

[0001] The present invention relates to elastomeric spherical particles, a dispersion of elastomeric spherical particles, and a method for producing the same. [Background technology]

[0002] Conventionally, raw rubber used in rubber products has been [1] Polymers whose repeating units consist only 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 are essentially acrylate units, such as acrylic rubber. [5] A polymer, such as an ethylene-propylene rubber, having a repeating unit of ethylene, an α-olefin having 3 to 12 carbon atoms, and optionally a non-conjugated polyene; [6] Polymers whose repeating units are dimethylsiloxane units, such as silicone rubber. are listed and are widely used.

[0003] Elastomer (rubber) spherical particles, 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] On the other hand, silicone rubber spherical particles and powders have been proposed for use in a wide range of industrial fields. For example, it has been suggested that it be added to synthetic resin materials (Patent Documents 1 and 2), synthetic rubber materials (Patent Document 3), cosmetics (Patent Documents 4 to 7), and the like.

[0005] Silicone rubber spherical particles are compounded and used, taking advantage of their flexibility, as a stress-reducing agent for organic resins such as epoxy resin. The difference in the thermal expansion coefficient between electronic components and organic resins such as epoxy resin can cause stress to be applied to the resin, which can lead to cracks and breakage, and adding 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 in which the surface of silicone rubber spherical particles is coated with polyorganosilsesquioxane (Patent Document 9).

[0007] In addition, a method for preparing silicone-containing rubber spherical particles by copolymerizing a (meth)acrylic acid ester and a diorganopolysiloxane having a radically polymerizable functional group-containing organic group at one end in an emulsion system has also been disclosed (Patent Document 10). The spherical particles are used for the purpose of imparting lubricity to thermoplastic resins.

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

[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 and smoothness to cosmetics, creating a natural finish by scattering light, 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 composite silicone powders in which silicone rubber spherical particles are coated with polyorganosilsesquioxane resin (Patent Document 14). These silicone rubber spherical particles and composite particles in which silicone rubber spherical particles are coated with polyorganosilsesquioxane resin can impart a soft feel to cosmetics in addition to the above-mentioned sensation of use. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Special Publication No. 63-12489 [Patent Document 2] Special Publication No. 6-55805 [Patent Document 3] Japanese Patent Application Publication No. 2-102263 [Patent Document 4] Japanese Patent Application Publication No. 8-12546 [Patent Document 5] Japanese Patent Application Publication No. 8-12545 [Patent Document 6] Special Publication No. 4-17162 [Patent Document 7] Special Publication No. 4-66446 [Patent Document 8] Japanese Patent Application Publication No. 58-219218 [Patent Document 9] Japanese Patent Application Publication No. 8-85753 [Patent Document 10] Japanese Patent Application Publication No. 10-182987 [Patent Document 11] Japanese Patent Application Laid-Open No. 2001-40214 [Patent Document 12] Japanese Patent Application Publication No. 63-297313 [Patent Document 13] Japanese Patent Application Publication No. 8-12524 [Patent Document 14] Japanese Patent Application Publication No. 9-20631 Summary of the Invention [Problem to be solved by the invention]

[0012] However, when these silicone rubber spherical particles, which are blended into resins, cosmetics, etc., are released or spilled into the natural environment, such as soil, land water, seawater, or the ocean, they are not decomposed because they do not have a degradable skeleton or unit within their particle structure, and are therefore expected to continue to remain in the environment. Furthermore, because these particles are very small in diameter, it is extremely difficult to recover them, and it is currently unavoidable that they will end up in the ocean, etc.

[0013] In addition, plastics that have flowed into the ocean / microplastics that have broken down into tiny pieces have the ability to adsorb harmful substances and pathogens in the environment, raising concerns that they may have a negative impact on the ecosystem, and so there are also moves to regulate microplastics.

[0014] Against this background, there is a growing demand for silicone rubber or elastomer (rubber) spherical particles that decompose in the environment after use and do not remain as particles (solid matter).For elastomer (rubber) spherical particles to decompose in the environment, the cross-linked structure of the particles needs to be broken down and cleaved 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 (rubber) spherical particles, dispersions of elastomer spherical particles, and methods for producing the same, whose constituent units are copolymers that are highly degradable in natural environments, including soil, land water, and ocean / seawater, in response to external stimuli such as light, heat, acid, and base. Another object of the present invention is to provide a copolymer that is suitable for producing the above-mentioned elastomer (rubber) spherical particles and that has high degradability in response to external stimuli. [Means for solving the problem]

[0016] As a result of intensive research conducted by the present inventors to achieve the above-mentioned object, they have found that the above-mentioned problems can be solved by a copolymer having a specific polyester structure and a polyether structure, elastomer spherical particles made of a polymer containing structural units derived from said copolymer, and a dispersion thereof, and have thus completed the present invention.

[0017] Therefore, the present invention provides the following copolymer, elastomer spherical particles, dispersion of elastomer spherical particles, and methods for producing them. [1]. A polyester-polyether copolymer having at least two radically polymerizable unsaturated groups in one molecule, represented by the following general formula (1) or (2): [ka] (In general formula (1), R 1 each independently represents a divalent hydrocarbon group having 1 to 10 carbon atoms, and R 2 each independently represents a radically 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, l independently represents a number of 1≦l≦1,000, m independently represents a number of 1≦m≦1,000, and each n independently represents a number of 1≦n≦100. In general formula (2), R 3 each independently represents a divalent hydrocarbon group having 1 to 10 carbon atoms, and 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. [ka] (In general formulas (3a), (3b), (3c), (4a) and (4b), R 5 each independently represents a divalent hydrocarbon group having 1 to 8 carbon atoms, and R 6 represents a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms.) [2]. 2. The polyester-polyether copolymer according to claim 1, which is represented by the following general formula (5): [ka] (In general formula (5), R 1 each independently represents a divalent hydrocarbon group having 1 to 10 carbon atoms, and 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. [ka] (In general formulas (3a), (3b) and (3c), R 5 each independently represents a divalent hydrocarbon group having 1 to 8 carbon atoms, and R 6 represents a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms.) [3]. Elastomer spherical particles having a volume average particle size of 0.5 to 200 μm and made of a polymer containing structural units derived from a copolymer having a polyester structure and a polyether structure. [4]. The elastomer spherical particles according to [3], wherein the copolymer is a polyester-polyether copolymer having at least two radically polymerizable unsaturated groups in one molecule. [5]. The elastomer spherical particles according to [4], wherein the copolymer is a polyester-polyether copolymer represented by the following general formula (1) or (2): [ka] (In general formula (1), R 1 each independently represents a divalent hydrocarbon group having 1 to 10 carbon atoms, and R 2each independently represents a radically 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, l independently represents a number of 1≦l≦1,000, m independently represents a number of 1≦m≦1,000, and each n independently represents a number of 1≦n≦100. In general formula (2), R 3 each independently represents a divalent hydrocarbon group having 1 to 10 carbon atoms, and 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. [ka] (In general formulas (3a), (3b), (3c), (4a) and (4b), R 5 each independently represents a divalent hydrocarbon group having 1 to 8 carbon atoms, and R 6 represents a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms.) [6]. The elastomer spherical particles according to [5], wherein the copolymer is a polyester-polyether copolymer represented by the following general formula (5): [ka] (In general formula (5), R 1 each independently represents a divalent hydrocarbon group having 1 to 10 carbon atoms, and 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. [ka] (In general formulas (3a), (3b) and (3c), R 5 each independently represents a divalent hydrocarbon group having 1 to 8 carbon atoms, and R 6represents a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms.) [7]. A dispersion of elastomer spherical particles obtained by dispersing the elastomer spherical particles according to any one of [3] to [6] in at least one dispersant selected from silicone oil, hydrocarbon oil, higher fatty acid, ester oil, liquid oil, and water. [8]. A method for producing elastomer spherical particles according to any one of [3] to [6], comprising the following steps (i) to (iii): (i) (A) a copolymer having a polymerizable group and having a polyester structure and a polyether structure, (B) an oil phase component or an aqueous phase component that is insoluble in the component (A); (C) a surfactant, and (D) A step of preparing an O / O type or O / W type emulsion by stirring and emulsifying a polymerization initiator. (ii) A step of polymerizing the component (A) in the O / O type or O / W type emulsion obtained in the step (i) to obtain a dispersion of elastomer spherical particles. (iii) A step of obtaining elastomer spherical particles by washing and drying the continuous phase (B) component from the dispersion of elastomer spherical particles obtained in the step (ii). [9]. Step (i) is (A) a copolymer having a polymerizable group and having a polyester structure and a polyether structure, (B) an oil phase component that is insoluble in the component (A); (C) a surfactant, and (D) A step of stirring and emulsifying a polymerization initiator to obtain an O / O type emulsion. [Effects of the Invention]

[0018] The copolymers of the present invention have a polyester structure, which is a degradable functional group (unit), and the crosslinked structure is cleaved in the presence of water, making them degradable. In particular, copolymers having a poly-ε-caprolactone structure, which is a microorganism-recognition backbone, among the polyester structures, are expected to be environmentally degradable and therefore can be used in various industrial fields. In particular, they are expected to be used not only for the production of the elastomer spherical particles of the present invention, but also as replacements for various organic resins / plastics or as new resin / plastic materials. Furthermore, the elastomer spherical particles of the present invention have a polyester structure, which is a degradable functional group (unit), and the crosslinked structure is cleaved in the presence of water, making them degradable. In particular, particles having a poly-ε-caprolactone structure, which is a microorganism-recognition skeleton, as the polyester structure in the particles can be expected to be environmentally degradable. Therefore, the elastomer spherical particles of the present invention are degradable particles and are expected to be environmentally friendly materials. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is an electron microscope photograph of the elastomer spherical particles obtained in Example 1. [Figure 2] 2A and 2B are electron microscope photographs of the elastomer spherical particles obtained in Example 5, where FIG. 2A is a photograph at a magnification of 200 times, and FIG. 2B is a photograph at a magnification of 1,000 times. DETAILED DESCRIPTION OF THE INVENTION

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

[0021] [Copolymer] The copolymer of the present invention is represented by the following general formula (1) or (2), and is a polyester-polyether copolymer having at least two radically polymerizable unsaturated groups in one molecule.

[0022] [ka]

[0023] In general formula (1), R 1 each independently represents a divalent hydrocarbon group having 1 to 10 carbon atoms, and R 2 each independently represents a radically 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, l independently represents a number of 1≦l≦1,000, m independently represents a number of 1≦m≦1,000, and each n independently represents a number of 1≦n≦100.

[0024] In general formula (2), R 3 each independently represents a divalent hydrocarbon group having 1 to 10 carbon atoms, and 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.

[0025] [ka]

[0026] In general formulas (3a), (3b), (3c), (4a) and (4b), R 5 each independently represents a divalent hydrocarbon group having 1 to 8 carbon atoms, and R 6 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 3Examples 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 4 represents a radically 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 alkylene groups include methylene, ethylene, propylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, and octamethylene groups, and preferably methylene, ethylene, trimethylene, and tetramethylene groups. In general formulas (3a), (3b), (3c), (4a) and (4b), R 6 Examples of the hydrocarbon group having 1 to 3 carbon atoms represented by R include alkyl groups having 1 to 3 carbon atoms such as a methyl group, an ethyl group, and a propyl group. 6 is preferably a hydrogen atom or a methyl group. The radically polymerizable functional group-containing organic groups represented by the general formulae (3a), (3b), (3c), (4a), and (4b) are residues derived from polymerizable monomers, and specific examples of the polymerizable monomers include hydroxyl group-containing (meth)acrylic acid esters and isocyanate group-containing (meth)acrylic acid esters.

[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 acrylate, (meth)acryloyloxyethyl succinate, and (meth)acryloyloxyethyl phthalate. Examples of the isocyanate group-containing acrylic ester include isocyanate ethyl (meth)acrylate, isocyanate propyl (meth)acrylate, isocyanate butyl (meth)acrylate, and isocyanate hexyl (meth)acrylate.

[0031] In the general formula (1), each k is independently a number in the range of 1≦k≦10, and preferably a number in the range of 1≦k≦6. In the general formula (2), each p is independently a number in the range of 1≦p≦10, and preferably a number in the range of 1≦p≦6. Furthermore, each n in the general formula (1) is independently a number in the range of 1≦n≦100, preferably a number in the range of 1≦n≦30, and more preferably a number in the range of 2≦n≦10. In the general formula (2), each q is independently a number satisfying 1≦q≦100, preferably a number satisfying 1≦q≦30, and more preferably a number satisfying 2≦q≦10. If the values ​​of n and q are too large, the crystallinity will increase due to intramolecular / intermolecular interactions of the polymer caused by the ester bond sites, which may affect the handleability in the emulsification step described below. In the general formula (1), l is a number in the range of 1≦l≦1,000, and preferably 2≦l≦100. In the general formula (1), m is a number in the range of 1≦m≦1,000, and preferably 10≦m≦500. In the general formula (2), l is a number in the range of 1≦l≦1,000, and preferably 2≦l≦100. In the general formula (2), m is a number satisfying 1≦m≦1,000, and preferably a number satisfying 10≦m≦500.

[0032] The copolymer of the present invention is preferably a copolymer represented by the following general formula (5) from the viewpoints of ease of handling of raw materials and ease of production. [ka] In general formula (5), R 1 each independently represents a divalent hydrocarbon group having 1 to 10 carbon atoms, and R 2each 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. [ka] In general formulas (3a), (3b) and (3c), R 5 each independently represents a divalent hydrocarbon group having 1 to 8 carbon atoms, and R 6 represents a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms.

[0033] The copolymer of the present invention can be produced, for example, by the method described below.

[0034] [Elastomer spherical particles] The elastomer spherical particles of the present invention are made of a polymer containing structural units derived from a copolymer having a polyester structure and a polyether structure.

[0035] The shape of the elastomeric spherical 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 to 1.6, and even more preferably 1 to 1.4. As described below, when a copolymer having a polyester structure and a polyether structure is emulsified and dispersed in a continuous phase using a surfactant or the like and then crosslinked, the resulting particles have a spherical shape. The shape of the elastomeric spherical particles can be confirmed by observation using, for example, an optical microscope or an 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.

[0036] In the present invention, the volume average particle diameter of the elastomer spherical particles is in the range of 0.5 to 200 μm, more preferably 1 to 100 μm. If the volume average particle diameter is greater than the upper limit, the particles may lose their smoothness, resulting in a rough texture and reduced light diffusion properties. If the volume average particle diameter is less than the lower limit, the particles may become less fluid and more cohesive, making it difficult to provide sufficient smoothness and light diffusion properties, which is undesirable. The volume average particle size of the elastomeric spherical particles of the present invention is a value measured as follows. First, prior to measuring the volume average particle size, the particle sizes of 50 particles randomly selected from a micrograph of the elastomeric spherical particles are measured, and the average value is determined to be equal to or less than 1 μm. A dispersion in which the elastomeric spherical particles are redispersed in water using various surfactants is used. If the result is 1 μm or more, the volume average particle size is a value measured by the electrical resistance method. If the result is less than 1 μm, the volume average particle size is a value measured by the laser diffraction / scattering method.

[0037] The rubber (elastomer) that is a component of the elastomer spherical particles is preferably free of tack or stickiness. The rubber hardness, 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. The rubber hardness, measured using an Asker rubber hardness tester type C 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 is less than 5, the cohesion may increase and dispersibility may decrease, while if the rubber hardness is more than 90, the soft feel may decrease, which is undesirable.

[0038] The elastomer spherical particles of the present invention are preferably produced by polymerizing a polyester-polyether copolymer having at least two radically polymerizable unsaturated groups in one molecule.

[0039] 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). [ka] (In general formula (1), R 1 each independently represents a divalent hydrocarbon group having 1 to 10 carbon atoms, and R 2 each independently represents a radically 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, l independently represents a number of 1≦l≦1,000, m independently represents a number of 1≦m≦1,000, and each n independently represents a number of 1≦n≦100. In general formula (2), R 3 each independently represents a divalent hydrocarbon group having 1 to 10 carbon atoms, and 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. [ka] (In general formulas (3a), (3b), (3c), (4a) and (4b), R 5 each independently represents a divalent hydrocarbon group having 1 to 8 carbon atoms, and R 6 represents a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms.)

[0040] 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.

[0041] R 3Examples of alkylene groups include methylene, ethylene, propylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, and octamethylene groups, and preferably methylene, ethylene, trimethylene, and tetramethylene groups.

[0042] R 2 represents a radically polymerizable functional group-containing organic group represented by general formula (3a), (3b) or (3c), and R 4 represents a radically 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 alkylene groups include methylene, ethylene, propylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, and octamethylene groups, and preferably methylene, ethylene, trimethylene, and tetramethylene groups. In general formulas (3a), (3b), (3c), (4a) and (4b), R 6 Examples of the hydrocarbon group having 1 to 3 carbon atoms represented by R include alkyl groups having 1 to 3 carbon atoms such as a methyl group, an ethyl group, and a propyl group. 6 is preferably a hydrogen atom or a methyl group. The radically polymerizable functional group-containing organic groups represented by the general formulae (3a), (3b), (3c), (4a), and (4b) are residues derived from polymerizable monomers, and specific examples of the polymerizable monomers include hydroxyl group-containing (meth)acrylic acid esters and isocyanate group-containing (meth)acrylic acid esters.

[0043] 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 acrylate, (meth)acryloyloxyethyl succinate, and (meth)acryloyloxyethyl phthalate. Examples of the isocyanate group-containing acrylic ester include isocyanate ethyl (meth)acrylate, isocyanate propyl (meth)acrylate, isocyanate butyl (meth)acrylate, and isocyanate hexyl (meth)acrylate.

[0044] The polyester structure 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 be highly degradable. 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. From the viewpoints of degradability and ease of handling, those having a poly-ε-caprolactone structure are particularly preferred.

[0045] In the general formula (1), each k is independently a number in the range of 1≦k≦10, and preferably a number in the range of 1≦k≦6. In the general formula (2), each p is independently a number in the range of 1≦p≦10, and preferably a number in the range of 1≦p≦6. Furthermore, each n in the general formula (1) is independently a number in the range of 1≦n≦100, preferably a number in the range of 1≦n≦30, and more preferably a number in the range of 2≦n≦10. In the general formula (2), each q is independently a number satisfying 1≦q≦100, preferably a number satisfying 1≦q≦30, and more preferably a number satisfying 2≦q≦10. If the values ​​of n and q are too large, the crystallinity will increase due to intramolecular / intermolecular interactions of the polymer caused by the ester bond sites, which may affect the handleability in the emulsification step described below. In the general formula (1), l is a number in the range of 1≦l≦1,000, and preferably 2≦l≦100. In the general formula (1), m is a number in the range of 1≦m≦1,000, and preferably 10≦m≦500. In the general formula (2), l is a number in the range of 1≦l≦1,000, and preferably 2≦l≦100. In the general formula (2), m is a number satisfying 1≦m≦1,000, and preferably a number satisfying 10≦m≦500.

[0046] 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 ease of production. [ka] (In general formula (5), R 1 each independently represents a divalent hydrocarbon group having 1 to 10 carbon atoms, and 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 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 formula (6), R 3 each independently represents a divalent hydrocarbon group having 1 to 10 carbon atoms, and 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.

[0047] [Method of producing polyester-polyether copolymer] Examples of methods for producing polyester-polyether copolymers include a method in which various polyethers containing active hydrogen, such as polyethers, carboxy-modified polyethers, and amino-modified polyethers, are used as starting materials, and cyclic-ε-caprolactone is subjected to ring-opening polymerization to obtain poly-ε-caprolactone-modified polyethers. A polymerizable monomer having a radically polymerizable unsaturated group is introduced into the poly-ε-caprolactone-modified polyethers via an ester bond, an ether bond, a urethane bond, an amide bond, or the like. From the viewpoint of reactivity, the terminal structure of the various polyethers is preferably a structure in which a reactive functional group is bonded to a primary carbon atom.

[0048] The reaction conditions in the above production method include, for example, the following, but are not limited to these reaction conditions. For example, 3 to 4 equivalents (functional group equivalents) of ε-caprolactone are added to 1.0 equivalent of a polyether containing active hydrogen, such as a polyether or a carboxy-modified polyether, and the mixture is reacted at 120°C for 6 hours in the presence of a conventionally known ring-opening polymerization catalyst to obtain a poly-ε-caprolactone-modified polyether. Next, 1.0 to 1.25 equivalents (1.0 to 1.25 moles) of acrylic acid chloride per functional group, or a reaction catalyst depending on the circumstances, is added to 1.0 mole of the hydroxyl groups of the obtained poly-ε-caprolactone-modified polyether, and the mixture is reacted at 40 to 100° C. for 4 hours or more. After the reaction, the product (crude product) is filtered, washed with water, and / or subjected to an adsorption step to remove by-products, and finally the solvent is distilled off to obtain poly-ε-caprolactone acrylic-modified polyether (polyester-polyether copolymer).

[0049] When polyether is used as the starting material, examples of polyester-polyether copolymers include those shown in formulas (7a) and (7b) (only one end is shown due to the symmetrical structure). [ka]

[0050] 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.

[0051] 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). [ka]

[0052] In formulas (8a) and (8b), 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. 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.

[0053] When an amino-modified polyether is used as a starting material, examples of polyester-polyether copolymers include those shown in formulas (9a) and (9b) (only one end is shown due to the symmetrical structure). [ka]

[0054] In formulas (9a) and (9b), 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. Furthermore, l, m, s, and u are 1≦l≦1,000, 1≦m≦1,000, 1≦s≦30, and 0≦u≦10, and preferably 2≦l≦100, 10≦m≦500, 2≦s≦10, and 1≦u≦10.

[0055] 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 organic titanium compounds such as tetramethoxytitanium, tetraethoxytitanium, tetra-n-propoxytitanium, and tetrabutoxytitanium; organic tin 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.

[0056] The amount of the ring-opening polymerization catalyst added may be in the range of 10 to 10,000 ppm, preferably 10 to 1,000 ppm, relative to the ε-caprolactone monomer (cyclic-ε-caprolactone).

[0057] 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 conventionally known catalysts may be used.

[0058] 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). Of these, amine catalysts are preferred from the standpoint of the stability of the product obtained by the esterification reaction and from the economical standpoint.

[0059] When using an amine catalyst, a dehydration condensation agent may be added to improve the reaction efficiency. Examples of the dehydration condensation agent 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).

[0060] The (urethanization) catalyst used in the urethanization reaction may be any known catalyst, and is not limited thereto. Specific examples 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, and dibutyltin dilaurate (DBTL); organic titanium compounds such as tetramethoxytitanium, tetraethoxytitanium, tetra-n-propoxytitanium, tetrabutoxytitanium, titanium tetraacetylacetonate, and titanium diisopropoxybis(ethylacetoacetate); and organic zirconium compounds such as n-propyl zirconate, n-butyl zirconate, zirconium tetraacetylacetonate, and zirconium dibutoxybis(ethylacetoacetate).

[0061] The amount of catalyst added when introducing these polymerizable monomers having a radically polymerizable unsaturated group may be in the range of 10 to 10,000 ppm, preferably 10 to 1,000 ppm, based on the polymerizable monomer.

[0062] During the reaction, a polymerization inhibitor or antioxidant can be used to suppress the polymerization reaction of the (meth)acrylate group during the reaction. Specific 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, and 2,5-dihydroxy-p-benzoquinone.

[0063] Another example of a method for producing a polyester-polyether copolymer is a method in which poly-ε-caprolactone-modified (meth)acrylate represented by the following formula (10) is subjected to an esterification reaction with the above-mentioned carboxy-modified polyether. Commercially available poly-ε-caprolactone-modified (meth)acrylate products include, for example, Placcel FA2D, Placcel FA10L, Placcel FN2D, and Placcel FM4 (manufactured by Daicel Corporation). [ka] In general formula (10), R 7 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 3 carbon atoms, and is preferably a hydrogen atom or a methyl group. v satisfies 1≦v≦30, and preferably 1≦v≦10.

[0064] Examples of the production method include, but are not limited to, the methods shown below. To 1.0 mole of the carboxy group of the carboxy-modified polyether, 1.0 to 1.25 moles of poly-ε-caprolactone-modified (meth)acrylate (formula (10)) in terms of hydroxyl group equivalent and 0.1 to 5.0 moles of an esterification catalyst are mixed and stirred for about 10 to 30 minutes at 15 to 150°C. Optionally, 1.0 to 1.25 moles of a dehydration condensation agent is added, and the mixture is reacted at 15 to 150°C for 4 to 20 hours. After the reaction, the reaction product is filtered, washed with water, and subjected to an adsorption treatment step to remove by-products. The solvent is then distilled off to obtain a polyester-polyether copolymer.

[0065] The polyester-polyether copolymer is preferably liquid, and has a weight average molecular weight (Mw.) measured by gel permeation chromatography (GPC) of preferably 100 to 100,000, more preferably 300 to 10,000. If the weight average molecular weight is less than 100, the degradability of the resulting elastomer spherical particles may be poor, whereas if it is more than 100,000, it may be difficult to prepare the elastomer spherical particles.

[0066] In the filtration step, a dilution operation using a hydrophobic organic solvent may be carried out for the purpose of adjusting the viscosity of the reaction product. The hydrophobic organic solvent to be used is not particularly limited, but from the viewpoint of solubility / affinity, toluene, hexane, ethyl acetate, etc. are preferred.

[0067] The adsorption treatment step is intended to remove hydrochlorides that cannot be completely removed by washing with water, and to dehydrate, deodorize, and decolorize the waste. The adsorbent used in the adsorption treatment step may be any conventionally known adsorbent, and a combination of several types may be used. Preferred adsorbents include desiccants such as magnesium sulfate and sodium sulfate, activated carbon, and Kyoward series (manufactured by Kyowa Chemical Industry Co., Ltd.).

[0068] [Dispersion of elastomer spherical particles] The dispersion of elastomer spherical particles of the present invention is prepared by dispersing the elastomer spherical particles in at least one dispersion medium selected from silicone oil, hydrocarbon oil, higher fatty acid, ester oil, liquid oil, and water. Examples of the dispersion medium include silicone oil, hydrocarbon oil, higher fatty acid, ester oil, liquid oil and water, among which silicone oil, hydrocarbon oil, ester oil and water are preferred, and dimethylpolysiloxane, decamethylcyclopentasiloxane, liquid paraffin, isododecane, squalane, stearic acid, oleic acid, butyl stearate, decyl oleate, distilled water, ion-exchanged water and pure water are particularly preferred. The amount of elastomer spherical particles in the dispersion is preferably in the range of 5 to 80% by mass, more preferably 20 to 70% by mass, based on the total mass of the dispersion. If the amount of elastomer spherical particles is less than the above lower limit, productivity per elastomer particle will be low, which is undesirable because it will be inefficient. On the other hand, if the amount of elastomer spherical particles is more than the above upper limit, the viscosity of the dispersion will increase, making it difficult to handle, which is undesirable.

[0069] [Method for producing elastomer spherical particles and dispersion of elastomer spherical particles] The elastomeric spherical particles of the present invention can be produced, for example, by a method including the following steps (i) to (iii): The dispersion of the elastomeric spherical particles of the present invention can be produced by a method including the following steps (i) to (ii): (i) (A) a copolymer having a polymerizable group and having a polyester structure and a polyether structure, (B) an oil phase component or an aqueous phase component that does not dissolve the component (A); (C) Surfactant and (D) Polymerization initiator a process for preparing an O / O type or O / W type emulsion by stirring and emulsifying the above. (ii) A step of polymerizing the component (A) in the O / O type or O / W type emulsion obtained in the step (i) to obtain a dispersion of elastomer spherical particles. (iii) A step of obtaining elastomer spherical particles by washing and drying the continuous phase (B) component from the dispersion of elastomer spherical particles obtained in the step (ii).

[0070] Process (i) The components used in step (i) are as follows: As the copolymer containing a polyester structure and a polyether structure having a polymerizable group of component (A), a copolymer containing a polyester structure and a polyether structure having a polymerizable group, which is contained as a constituent unit of the elastomer spherical particles of the present invention, can be used, and preferably the polyester-polyether copolymer having at least two radically polymerizable unsaturated groups in one molecule, can be used. As mentioned above, specific examples of component (A) include the polyester-polyether copolymers represented by general formula (1) or (2), and more preferred examples include the polyester-polyether copolymers represented by general formula (5) or (6).

[0071] Component (B) is a component that becomes the continuous phase of the emulsion, and is either an oil phase component that does not dissolve (is insoluble or incompatible with) component (A) or has low affinity for it, or an aqueous phase component.

[0072] Examples of the oil phase component of component (B) include silicone oil, hydrocarbon oil, higher fatty acid, ester oil, liquid oil, etc., which 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, 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, 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 is preferable, and 10,000 mm 2 If the kinematic viscosity is greater than the above upper limit, it may be difficult to emulsify in step (i) or to obtain fine spherical particles with a narrow particle size distribution.

[0079] When an aqueous phase component is used as component (B), examples of the aqueous phase component of component (B) include distilled water, ion-exchanged water, pure water, and ultrapure water.

[0080] The surfactant of component (C) is not particularly limited and may be a nonionic surfactant, anionic surfactant, cationic surfactant, or amphoteric surfactant, which may be used alone or in combination of two or more.

[0081] Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyethylene glycol fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbit fatty acid esters, glycerin fatty acid esters, polyoxyethylene glycerin fatty acid esters, polyglycerin fatty acid esters, propylene glycol fatty acid esters, polyoxyethylene castor oil, polyoxyethylene hydrogenated castor oil, polyoxyethylene hydrogenated castor oil fatty acid esters, polyoxyethylene alkylamines, polyoxyethylene fatty acid amides, polyoxyethylene-modified organopolysiloxanes, and polyoxyethylene polyoxypropylene-modified organopolysiloxanes. Examples of polyoxyethylene-modified organopolysiloxanes include linear polyether-modified silicones (trade names: KF-6015, KF-6017, KF-6017P, manufactured by Shin-Etsu Chemical Co., Ltd.), linear alkyl-co-modified polyether-modified silicones (trade name: KF-6048, manufactured by Shin-Etsu Chemical Co., Ltd.), branched polyether-modified silicones (trade name: KF-6028, KF-6028P, manufactured by Shin-Etsu Chemical Co., Ltd.), and branched alkyl-co-modified polyether-modified silicones (trade name: KF-6038, manufactured by Shin-Etsu Chemical Co., Ltd.).

[0082] Examples of anionic surfactants include alkyl sulfate salts such as sodium lauryl sulfate, polyoxyethylene alkyl ether sulfate salts, polyoxyethylene alkyl phenyl ether sulfate salts, alkyl benzene sulfonates, polyoxyethylene alkyl phenyl ether sulfonates, alkyl diphenyl ether disulfonates, alkanesulfonates, N-acyltaurate salts, dialkyl sulfosuccinates, monoalkyl sulfosuccinates, polyoxyethylene alkyl ether sulfosuccinates, fatty acid salts, polyoxyethylene alkyl ether carboxylate salts, N-acylamino acid salts, monoalkyl phosphate salts, dialkyl phosphate salts, polyoxyethylene alkyl ether phosphate salts, and the like.

[0083] Examples of cationic surfactants include alkyltrimethylammonium salts, dialkyldimethylammonium salts, polyoxyethylenealkyldimethylammonium salts, dipolyoxyethylenealkylmethylammonium salts, tripolyoxyethylenealkylammonium salts, alkylbenzyldimethylammonium salts, alkylpyridinium salts, monoalkylamine salts, and monoalkylamidoamine salts.

[0084] Examples of amphoteric surfactants include alkyldimethylamine oxide, alkyldimethylcarboxybetaine, alkylamidopropyldimethylcarboxybetaine, alkylhydroxysulfobetaine, and alkylcarboxymethylhydroxyethylimidazolinium betaine.

[0085] As the surfactant, a nonionic surfactant or an anionic surfactant is preferred, since a small amount of the surfactant can emulsify the oil phase components and produce fine particles.

[0086] When an oil phase component is used as component (B), the surfactant (C) preferably has an HLB of 2.0 to 18.0. When an aqueous phase component is used as component (B), the surfactant (C) preferably has an HLB of 6.0 to 18.0, more preferably 9.0 to 18.0.

[0087] The amount of surfactant 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 emulsion. If the amount of surfactant added is less than 0.01 part by mass, poor emulsification or failure to obtain fine particles may occur. If the amount of surfactant added is more than 25 parts by mass, fine particles may not be obtained or the dispersibility of the elastomer spherical particles may be insufficient.

[0088] The amount of component (A) in the emulsion is preferably 1.0 to 80 parts by mass, more preferably 10 to 60 parts by mass, per 100 parts by mass of the emulsion. If the amount of component (A) is less than 1.0 part by mass, it will be disadvantageous in terms of production efficiency, and if it is more than 80 parts by mass, it may be difficult to obtain a dispersion of elastomer spherical particles.

[0089] As the polymerization initiator of component (D), a conventional radical polymerization initiator may be used, and in the presence of the initiator, reaction and curing can be carried out using a heating method, a redox method, light irradiation method, or the like.

[0090] As these polymerization initiators, peroxides, azo-based initiators, redox-based initiators in which an oxidizing agent and a reducing agent are combined, photopolymerization initiators, and the like can be used.

[0091] 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, and hydrogen peroxide. Alternatively, perchlorates such as potassium perchlorate and sodium perchlorate may be used.

[0092] 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.

[0093] Examples of redox initiators include a combination of ferrous sulfate, sodium pyrophosphate, glucose, and hydroperoxide, a combination of ferrous sulfate, ethylenediaminetetraacetic acid disodium salt, Rongalite, and hydroperoxide, etc. Also, a thermal polymerization initiator and a photopolymerization initiator can be used in combination.

[0094] Examples of the photopolymerization initiator 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, phenylglyoxylic 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, and (2,4,6-trimethylbenzoyl)-diphenylphosphine oxide. Benzoin alkyl ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether can also be used.

[0095] Among the above polymerization initiators, peroxides, azo-based initiators, and photopolymerization initiators used in the heating method or light irradiation method are preferred from the viewpoint of stability during the emulsion polymerization reaction.

[0096] The amount of polymerization initiator added is preferably within 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 0.01 part by mass, curing may be insufficient, while if it is more than 5.0 parts by mass, contamination from reaction residues may occur, resulting in odors, bleeding, etc.

[0097] [Other additives] In the method for producing elastomer spherical particles of the present invention, various additives may be added in step (i) as needed, in addition to the above-mentioned components (A), (B), (C), and (D). Examples of additives include thickeners, preservatives, pH adjusters, antioxidants, polymerization inhibitors, etc., and these may be used singly or in appropriate combinations of two or more in an appropriate amount within the range that does not impair the effects of the present invention.

[0098] The order in which the components are added and mixed in step (i) is not particularly limited. For example, the components (A) and (D) may be mixed, and then the components (B) and (C) may be added to the mixture of the components (A) and (D) to prepare an emulsion; alternatively, an emulsion may be prepared from the components (A), (B), and (C), and then the component (D) may be added. Alternatively, after preparing an emulsion from components (A), (B), (C), and (D), component (B) may be further added to the emulsion to achieve a desired concentration before subjecting the emulsion to step (ii).

[0099] A conventionally known emulsifying / dispersing machine may be used for emulsification to prepare an emulsion. Typical emulsifying / dispersing machines include a high-speed rotary shear type agitator such as a homomixer, a high-speed centrifugal radiation type agitator such as a homodisper, a high-pressure jet type emulsifying / dispersing machine such as a homogenizer, a colloid mill, an ultrasonic emulsifier, and a propeller agitator.

[0100] Process (ii) Step (ii) is a step of polymerizing (curing and crosslinking) the component (A) in the emulsion prepared in step (i) by the polymerization method described above to obtain a dispersion of elastomer spherical particles.

[0101] The polymerization reaction conditions can be appropriately determined depending on the type of (D) polymerization initiator. For example, when a peroxide or azo-based initiator is used as the (D) polymerization initiator, a heating method in which the polymerization reaction is carried out at a temperature of 30 to 80°C for 10 to 24 hours can be used. When a redox-based initiator is used as the (D) polymerization initiator, a redox polymerization method in which the polymerization reaction is carried out at a temperature of 30 to 70°C for 2 to 24 hours can be used. When a photopolymerization initiator is used as the (D) polymerization initiator, a photoirradiation method in which the polymerization reaction is carried out under light irradiation can be used. In the case of the light irradiation method, the light source and wavelength range used for light (UV) irradiation may be any known light source.

[0102] Process (iii) In the step (iii), the component (B) serving as the continuous phase is removed from the obtained dispersion of elastomer spherical particles by washing and drying, thereby obtaining elastomer spherical particles.

[0103] When the continuous phase (dispersion medium) is an aqueous phase component, specific methods for step (iii) include concentrating the dispersion by methods such as thermal dehydration, filtration, centrifugation, and decantation, followed by washing with water as necessary, and finally drying by heating under normal pressure or reduced pressure, spraying the dispersion into a heated air stream and drying by heating (spray drying), or drying by heating using a fluidized heat medium. Freeze drying is also an example of a method in which the dispersion is solidified, then reduced pressure is applied, and the dispersion medium is removed. If the elastomer spherical particles obtained after removing the dispersion medium are aggregated, they may be crushed using a mortar, jet mill, or the like.

[0104] When the continuous phase (dispersion medium) is an oil phase component, a specific method for step (iii) involves 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. By repeating this washing procedure multiple times, component (B) can be sufficiently removed and the solvent can be replaced. Examples of hydrophobic organic solvents that can be used in this process include toluene, hexane, and ethyl acetate. Thereafter, the mixture is subjected to a method of heat drying under normal pressure or reduced pressure, a method of heat drying using a fluid heat medium, freeze drying, or the like, to obtain elastomer spherical particles. [Example]

[0105] 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 these examples. In the examples, the kinematic viscosity is a value measured at 25°C, and the "%" indicating the concentration and content refers to "% by mass." The hardness (penetration) of the cured rubber is a value measured in accordance with the Standards and Regulations of the Society of Rubber Industry, Japan (SRIS).

[0106] The molecular weight of the polyester-polyether copolymer (poly-ε-caprolactone acrylate modified polyether) is a weight average molecular weight measured by GPC under the following conditions using polystyrene as a standard substance. [Measurement conditions] Developing solvent: tetrahydrofuran (THF) Flow rate: 0.60mL / min Detector: Refractive index detector (RI) Column: TSK Guardcolumn SuperH-H TSKgel SuperHM-N TSKgel SuperH2500 (All manufactured by Tosoh Corporation) Column temperature: 40℃ Sample injection volume: 50 μL (0.5% by mass THF solution)

[0107] [Biodegradability evaluation] Biodegradability was measured 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 the standard (control) substance. The degree of biodegradation was measured by measuring the oxygen consumption (biochemical oxygen consumption (BOD)) in a closed system in an incubator using a BOD meter, and calculating the degree of biodegradation based on the following formula. Biodegradation rate (%)=BOD-B / TOD×100 -(11) BOD: Biochemical oxygen consumption of the test suspension or control (measured value: mg) B: Average biochemical oxygen consumption of the plant source blank (measured in mg) TOD: Theoretical oxygen consumption (calculated value: mg) required for the complete oxidation of the test substance or sodium benzoate

[0108] [Synthesis of poly-ε-caprolactone acrylate modified polyether 1] A 2-L separable flask equipped with a stirrer, thermometer, condenser, and dropping funnel was charged with 500 g of primary-terminated EO / PO polyether (Sanyo Chemical Industries, Ltd., molecular weight 2,000, OH group equivalent: 0.0975 mol / 100 g), 183.6 g of ε-caprolactone (trade name: PLACCEL M, Daicel Corporation, 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-modified polyether 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 a uniform solution. 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 at 60°C for 4 hours. The resulting crude product was filtered under pressure, washed with a sodium chloride solution using a separatory funnel, and centrifuged. Then, magnesium sulfate, silica gel, activated carbon, etc. were added, and powder treatment by shaking was performed to adsorb and remove impurities. After removing various powders by pressure filtration, 0.22 g of dibutylhydroxytoluene (BHT) was added again, and the solvent was distilled off at 60-70°C and 50 mmHg or less to obtain poly-ε-caprolactone acrylate-modified polyether 1 (formula (12) below, weight-average molecular weight 2,880). [ka]

[0109] [Synthesis of poly-ε-caprolactone acrylate modified polyether 2] A 1-L separable flask equipped with a stirrer, thermometer, condenser, and dropping funnel was charged with 300 g of primary-terminated EO / PO polyether (Sanyo Chemical Industries, Ltd., molecular weight 2,000, OH group equivalent: 0.0975 mol / 100 g), 110.2 g of ε-caprolactone (trade name: PLACCEL M, Daicel Corporation, molecular weight 114.1), 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 (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-modified polyether obtained by the above operation was cooled to around room temperature, and then 100 g of dehydrated toluene, 0.96 g of dioctyltin dineodecanoate (trade name: Neostan U-830, manufactured by Nitto Kasei Co., Ltd., molecular weight 687.7) as a catalyst, and 0.12 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 a uniform solution. Then, 44.4 g of 2-isocyanatoethyl acrylate (trade name: Karenz AOI, manufactured by Showa Denko K.K., molecular weight 141.1) was added dropwise using a dropping funnel, and 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, followed by a quenching treatment. Subsequently, magnesium sulfate, silica gel, activated carbon, etc. were added, and impurities were adsorbed and removed by powder treatment through shaking. Various powders were removed by pressure filtration, and 0.12 g of dibutylhydroxytoluene (BHT) was added again, and the solvent was distilled off at 60-70°C and 50 mmHg or less to obtain poly-ε-caprolactone acrylate-modified polyether 2 (formula (13) below, weight-average molecular weight 3,120). [ka]

[0110] [Synthesis of poly-ε-caprolactone acrylate modified silicone] A 1-L separable flask equipped with a stirrer, a thermometer, a condenser, and a dropping funnel was charged with 300 g of carboxy-modified silicone (molecular weight 1,200, COOH group equivalent: 0.187 mol / 100 g), 202.8 g of poly-ε-caprolactone monoacrylate (trade name: Placcel FA2D, manufactured by Daicel Corporation, molecular weight 344.0, OH group equivalent: 0.291 mol / 100 g), 200 g of dehydrated toluene, and 6.85 g of 4-dimethylaminopyridine (DMAP) (manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight 122.2), 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) (Tokyo Chemical Industry Co., Ltd., molecular weight 206.3) dissolved in 173.6 g of dehydrated toluene was added dropwise using a dropping funnel, and the mixture was aged 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), followed by water washing with saturated aqueous sodium bicarbonate and 10% aqueous sodium chloride, in that order. After completing the above operations, 10 g each of 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 various powders by pressure filtration, 0.09 g of dibutylhydroxytoluene (BHT) was added as a polymerization inhibitor, and the solvent was distilled off at 60-70°C and 10 mmHg or less to obtain poly-ε-caprolactone acrylate-modified silicone (formula (14) below, weight-average molecular weight 2,130). [ka]

[0111] [Example 1] 60 g of poly-ε-caprolactone acrylate-modified polyether 1 and 0.48 g of the polymerization initiator 2,2'-azobis-(2,4-dimethylvaleronitrile) (hereinafter referred to as V-65) were placed in a 500 ml container and stirred at 1,000 rpm using a disper. Next, 10 g of branched polyether-modified silicone (trade name: KF-6028, manufactured by Shin-Etsu Chemical Co., Ltd., HLB: 4.0) and decamethylcyclopentasiloxane (trade name: KF-995, manufactured by Shin-Etsu Chemical Co., Ltd., kinematic viscosity at 25°C: 4.0 mmHg) were added. 2 50 g of cyclopentasiloxane (100%) was added to the container and stirred at 4,000-5,000 rpm using a homomixer. Thickening was observed, and stirring was continued for another 10 minutes, yielding an O / O emulsion. Subsequently, 80 g of decamethylcyclopentasiloxane was added while stirring at 1,500-2,000 rpm to dilute the mixture, yielding a white emulsion.

[0112] This emulsion was transferred to a 500 ml separable flask equipped with an anchor-type stirring blade, and the temperature was adjusted to 52-55°C using an oil bath. The emulsion was stirred and aged for 20 hours to obtain a dispersion of elastomer spherical particles.

[0113] Approximately 100 g of toluene was added to the resulting dispersion of elastomer spherical particles, and the mixture was stirred for a certain period of time in a separable flask equipped with an anchor-type impeller stirrer. The continuous phase, decamethylcyclopentasiloxane, was then removed by solid-liquid separation using pressure filtration. The above washing and separation procedure was repeated twice using toluene and once using ethanol to remove the continuous phase and replace it with a volatile solvent (<100°C). Finally, the mixture was allowed to stand and dry in a 70°C air thermostatic chamber for 24 hours or more, yielding the target product, white to pale yellow powdery elastomer spherical particles.

[0114] The obtained elastomer spherical particles were observed using an electron microscope (scanning microscope S-4700, manufactured by Hitachi High-Technologies Corporation), and were confirmed to be spherical elastomer particles with a particle size of approximately 100 μm. The resulting elastomer spherical particles were redispersed using a surfactant to form an aqueous solution, and the volume average particle size was measured by an electrical resistance method, confirming that it was 98 μm. An electron microscope photograph of the elastomer spherical particles made of poly-ε-caprolactone acrylate modified polyether 1 of Example 1 is shown in FIG. From the electron microscope photograph shown in FIG. 1, it was found that the aspect ratio of the elastomer spherical particles made of poly-ε-caprolactone acrylate-modified polyether 1 in Example 1 was approximately 1.

[0115] The hardness of the rubber constituting the rubber particles was measured as follows. 30.0 g of poly-ε-caprolactone acrylate-modified polyether 1 and 0.24 g of 2,2'-azobis-(2,4-dimethylvaleronitrile) (trade name: V-65, Fujifilm Wako Pure Chemical Industries, Ltd., molecular weight 248.4) were mixed and stirred, and the mixture was poured into an aluminum petri dish to a thickness of 10 mm. After leaving the mixture in a 70°C air thermostat for 1 hour, a flat rubber was obtained that was not sticky (tacky). The hardness of the resulting flat rubber was measured, and it was found to be 73 on an Asker C hardness scale and 55 on an Asker A hardness scale.

[0116] In accordance with the above method, the biodegradability of poly-ε-caprolactone acrylate-modified polyether 1 was evaluated and measured for 60 days at an incubation temperature of 22±1°C. As a result, the biodegradability of poly-ε-caprolactone acrylate-modified polyether 1 was 62% on average after 28 days and 73% on average after 60 days, which satisfied the criteria of 60% biodegradability after 28 days, and was therefore judged to be a "readily biodegradable substance." Therefore, if poly-ε-caprolactone acrylate-modified polyether 1 or elastomeric spherical particles made of poly-ε-caprolactone acrylate-modified polyether 1 is used and then released directly into the ocean via land waters, it is expected that it will eventually decompose without remaining in the environment as a copolymer or particles.

[0117] [Example 2] Elastomer spherical particles were obtained in the same manner as in Example 1, except that a linear polyether-modified silicone (product name: KF-6017, manufactured by Shin-Etsu Chemical Co., Ltd., HLB: 4.5) was used as the emulsifier instead of the branched polyether-modified silicone (product name: KF-6028). The resulting elastomer spherical particles were observed under an electron microscope in the same manner as in Example 1, and were confirmed to be elastomer spherical particles with a particle size of approximately 100 μm. The resulting elastomer spherical particles were redispersed using a surfactant to form an aqueous solution, and the volume average particle size was measured by an electrical resistance method, confirming that it was 72 μm.

[0118] [Example 3] Elastomeric spherical particles were obtained in the same manner as in Example 1, except that a linear polyether-modified silicone (trade name: KF-6017, manufactured by Shin-Etsu Chemical Co., Ltd., HLB: 4.5) was used as the emulsifier instead of the branched polyether-modified silicone (trade name: KF-6028), 20 g of a polyether-modified silicone gel activator (trade name: KSG-210, manufactured by Shin-Etsu Chemical Co., Ltd.) was also added when the linear polyether-modified silicone was added, and the amount of decamethylcyclopentasiloxane used during emulsification was changed from 50 g to 40 g. The resulting elastomer spherical particles were observed under an electron microscope in the same manner as in Example 1, and were confirmed to be elastomer spherical particles with a particle size of just under 100 μm. The resulting elastomer spherical particles were redispersed using a surfactant to form an aqueous solution, and the volume average particle size was measured by an electrical resistance method, confirming that it was 63 μm.

[0119] [Example 4] Component (B), which becomes the continuous phase during emulsification, was converted from cyclopentasiloxane to polydimethylsiloxane (trade name: KF-96-100cs, manufactured by Shin-Etsu Chemical Co., Ltd., kinematic viscosity at 25°C: 100 mm 2 Elastomer spherical particles were obtained in the same manner as in Example 3, except that the temperature was changed to (1 / s). The obtained elastomer spherical particles were observed under an electron microscope in the same manner as in Example 1, and it was found that the obtained elastomer spherical particles had a particle size of approximately 50 to 70 μm and a uniform particle size distribution. The resulting elastomer spherical particles were redispersed using a surfactant to form an aqueous solution, and the volume average particle size was measured by an electrical resistance method, confirming that it was 57 μm.

[0120] [Example 5] 60 g of poly-ε-caprolactone acrylate-modified polyether 2 and 0.48 g of radical polymerization initiator V-65 were placed in a 500 ml container and stirred at 1,000 rpm using a disperser to dissolve. Next, 10 g of linear polyether-modified silicone (trade name: KF-6017, HLB: 4.5), 20 g of polyether-modified silicone gel activator (trade name: KSG-210), and polydimethylsiloxane (trade name: KF-96-100cs, kinematic viscosity at 25°C: 100 mm) were added. 2 When 40 g of cyclopentasiloxane was added and stirred at 4,000-5,000 rpm using a homomixer, thickening was observed, and stirring was continued for an additional 10 minutes, yielding an O / O type emulsion. Subsequently, 70 g of cyclopentasiloxane was added while stirring at 1,500-2,000 rpm to dilute the mixture, yielding a white emulsion.

[0121] The steps after emulsion preparation were carried out in the same manner as in Example 1 to obtain elastomer spherical particles. The obtained elastomer spherical particles were observed under an electron microscope in the same manner as in Example 1, and it was found that the obtained elastomer spherical particles had a uniform particle size distribution with particle sizes of approximately 20 to 50 μm. The resulting elastomer spherical particles were redispersed using a surfactant to form an aqueous solution, and the volume average particle size was measured by an electrical resistance method, confirming that the particle size was 30 μm. An electron microscope photograph of the elastomer spherical particles made of poly-ε-caprolactone acrylate-modified polyether 2 in Example 5 is shown in Figure 2. The electron microscope photograph shown in Figure 2 reveals that the aspect ratio of the elastomer spherical particles made of poly-ε-caprolactone acrylate-modified polyether 2 in Example 5 was approximately 1.

[0122] In addition, when the hardness of the rubber constituting the rubber particles was measured in the same manner as in Example 1, a flat rubber without stickiness (tack) was obtained, and the rubber hardness values ​​were 76 on an Asker C hardness scale and 62 on an Asker A hardness scale.

[0123] In accordance with the above method, the biodegradability of poly-ε-caprolactone acrylate-modified polyether 2 was evaluated and measured for 60 days at an incubation temperature of 22±1°C. As a result, the biodegradability of poly-ε-caprolactone acrylate-modified polyether 2 was an average of 40% after 28 days and an average of 65% after 60 days, which met the criteria of 60% biodegradability after 60 days, and was therefore judged to be an "essentially biodegradable substance." Therefore, if poly-ε-caprolactone acrylate-modified polyether 2 or elastomeric spherical particles made of poly-ε-caprolactone acrylate-modified polyether 2 is used and then released directly into the ocean via land waters, it is presumed that it will eventually decompose without remaining in the environment as a copolymer or particles.

[0124] [Example 6] Elastomer spherical particles were obtained in the same manner as in Example 5, except that the amount of polydimethylsiloxane (trade name: KF-96-100cs), component (B), which serves as the continuous phase during emulsification, was changed from 40 g to 20 g. The obtained elastomer spherical particles were observed under an electron microscope in the same manner as in Example 1, and were confirmed to be elastomer spherical particles with a particle size of approximately 50 to 70 μm and a uniform particle size distribution. The resulting elastomer spherical particles were redispersed using a surfactant to form an aqueous solution, and the volume average particle size was measured by an electrical resistance method, confirming that the particle size was 26 μm.

[0125] [Comparative Example] The rubber hardness of the poly-ε-caprolactone acrylate modified silicone was measured in the same manner as in Example 1, and a flat rubber without stickiness (tack) was obtained, and the rubber hardness measured on an Asker C hardness scale was 71.

[0126] In accordance with the above method, the biodegradability of poly-ε-caprolactone acrylate-modified silicone was evaluated and measured for 28 days at an incubation temperature of 22±1°C. As a result, the biodegradability of poly-ε-caprolactone acrylate-modified silicone was only 26% on average, which did not meet the criterion of 60% biodegradability after 28 days, it was determined to be "not a readily biodegradable substance."

[0127] Due to their characteristic structural composition, the dispersions of copolymers and elastomer spherical particles of the present invention, as well as the elastomer spherical particles, are expected to be particularly useful in cosmetics, etc. Furthermore, because the copolymers and powders / particles contain polyester (especially poly-ε-caprolactone) and polyether structures, which are considered to be degradable skeletons, they are expected to exhibit and impart high biodegradability.

Claims

1. Elastomer spherical particles having a volume average particle size of 0.5 to 200 μm, which are made of a polymer containing a structural unit derived from a polyester-polyether copolymer, which is represented by the following general formula (1) or (2) and has at least two radically polymerizable unsaturated groups in one molecule: 【Chemistry 1】 (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), each k independently represents a number within the range of 1≦k≦10, each l independently represents a number within the range of 1≦l≦1,000, each m independently represents a number within the range of 1≦m≦1,000, and each n independently represents a number within the range of 1≦n≦100: In general formula (2), 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 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. 【Chemistry 2】 (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 represents a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms.)

2. The elastomer spherical particle described in claim 1, wherein the polyester-polyether copolymer is represented by the following general formula (5): 【Transformation 3】 (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: 【Chemistry 4】 (In general formulas (3a), (3b) and (3c), R 5 each independently represents a divalent hydrocarbon group having 1 to 8 carbon atoms; R 6 represents a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms.)

3. A dispersion of elastomer spherical particles, in which the elastomer spherical particles described in claim 1 or 2 are dispersed in at least one dispersant selected from silicone oil, hydrocarbon oil, higher fatty acid, ester oil, liquid oil, and water.

4. 3. A method for producing the elastomer spherical particles according to claim 1, comprising the following steps (i) to (iii): (i) (A) a copolymer having a polymerizable group and having a polyester structure and a polyether structure; (B) an oil phase component or an aqueous phase component that is insoluble in the component (A); (C) a surfactant, and (D) A step of preparing an O / O type or O / W type emulsion by stirring and emulsifying the polymerization initiator. (ii) A step of polymerizing the component (A) in the O / O type or O / W type emulsion obtained in the step (i) to obtain a dispersion of elastomer spherical particles. (iii) 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 the step (ii).

5. Step (i) is (A) a copolymer having a polymerizable group and having a polyester structure and a polyether structure; (B) an oil phase component that is insoluble in the component (A); (C) a surfactant, and The method according to claim 4, wherein (D) the polymerization initiator is stirred and emulsified to obtain an O / O type emulsion.

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