Reactive group-including polycaprolactone compound, novel silicone elastomer particles in which same is used, cosmetic composition, and other application

Abstract

[Problem] To provide silicone elastomer particles that comprise a crosslinked structure having an activity against biodegradability and that, when mixed into a cosmetic composition or similar, can achieve an equal or better tactile feeling and feeling of use as existing silicone elastomer particles, a reactive group-including polycaprolactone compound that comprises a specific structure and is useful as a raw material for a synthesis reaction for said silicone elastomer particles, and manufacturing methods for these. [Solution] A reactive group-including polycaprolactone compound (specifically, a compound selected from among a (meth)acrylic-modified polycaprolactone compound and an alkenyl-modified polycaprolactone compound) that has two or more modified polycaprolactone structures with the structure of structural formula (1) (in this formula, n is a number within the range 1-5, and Ra is a specific (meth)acrylic terminal group or alkenyl terminal group). Additionally, the use of said reactive group-including polycaprolactone compound as a raw material for silicone elastomer particles.

Description

Reactive group-containing polycaprolactone compound, novel silicone elastomer particles using the same, and cosmetic compositions and other uses

[0001] The present invention provides reactive group-containing polycaprolactone compounds useful as raw materials for synthetic reactions selected from radical polymerization and hydrosilylation reactions, and methods for producing them. Furthermore, the present invention relates to novel silicone elastomer particles that possess intersilicon-bridged structures derived from the reactive group-containing polycaprolactone compounds and that can impart an excellent feel and sensation to cosmetics. Furthermore, because the novel silicone elastomer particles possess crosslinked structures that are active toward biodegradation, the primary particles are expected to disintegrate in nature through decomposition reactions by microorganisms and the like, generating non-crosslinked siloxane molecules, and thus behave as biodegradable silicone elastomer particles. Furthermore, the present invention relates to cosmetic ingredients, cosmetic compositions, organic resin additives, and other uses containing the silicone elastomer particles, as well as methods for producing the silicone elastomer particles.

[0002] Silicone elastomer particles are obtained by curing addition-reaction-curable silicone compositions or condensation-reaction-curable silicone compositions, and although their particle size and oil absorption properties vary depending on the production method, they are widely used as cosmetic ingredients, stress relief agents for thermoplastic resins, etc. For example, the present applicant has proposed silicone particles with excellent dispersibility, high lipophilicity, and excellent storage stability, such as silicone particles containing alkylene groups having 4 to 20 carbon atoms, which are obtained by curing a crosslinkable composition for forming silicone particles described in Patent Document 1, which has a low content of silicon-bonded hydrogen atoms per unit mass and contains an alkenyl group having 4 to 20 carbon atoms, such as a hexenyl group.

[0003] On the other hand, the present applicant has focused on the fundamental problem of conventional silicone elastomer particles. That is, conventional silicone elastomer particles are formed through a crosslinking reaction of organopolysiloxane raw materials, such as a hydrosilylation reaction. However, this crosslinked structure is chemically stable, and if these silicone elastomer particles are released into the natural environment, it cannot be denied that they may remain in the natural environment without decomposing, at least for a short period of time, just like so-called microplastics. Therefore, in order to reduce the risk to the global environment, there is a potential demand in the market for silicone elastomer particles that have the performance to smoothly replace or substitute existing silicone elastomer particles and are expected to be highly biodegradable.

[0004] In view of such potential market demand, the present applicants have proposed silicone elastomer particles having a structure crosslinked by a divalent organic group having a partial structure formed by radical polymerization of vinyl acetate, as described in Patent Document 2. These silicone elastomer particles are expected to be highly biodegradable, and compared to conventional silicone elastomer particles, they are less likely to aggregate over time and give a smaller average secondary particle size, which has succeeded in realizing the properties of excellent dispersibility, ease of handling as a cosmetic raw material, storage stability, and stability in incorporation into systems.

[0005] However, when used as a cosmetic raw material, there is still a demand for silicone elastomer particles that can provide a feel equivalent to or even better than existing silicone elastomer particles and that are expected to be highly biodegradable.

[0006] On the other hand, polycaprolactone compounds are synthesized by ring-opening addition polymerization of ε-caprolactone, and are expected to have properties as a biodegradable raw material as well as a film-forming material. Patent Document 3 also discloses an (AB)n-type block copolymer containing a polycaprolactone structure and a polysiloxane structure. However, the document does not describe or suggest silicone elastomer particles having the polycaprolactone structure, and does not mention -C(=O)-CH=CH ２Nor does it disclose a (meth)acrylic-modified polycaprolactone compound having a terminal group represented by -C(=O)-CH=CH(CH3).

[0007] On the other hand, Non-Patent Documents 1 to 3 disclose the reaction of a polycaprolactone compound having a polyol terminal structure with butyroyl chloride or the like, but do not disclose a (meth)acrylic-modified polycaprolactone compound of a specific structure that has multiple polycaprolactone structures with a relatively low degree of polymerization in the molecule, all of whose terminal structures are (meth)acrylic terminal groups, and that is capable of forming silicone elastomer particles through a crosslinking reaction between polysiloxane structures or a radical polymerization reaction with a (meth)acrylic group-containing organopolysiloxane.

[0008] International Patent Publication WO2017 / 191798 International Patent Application PCT / JP2021 / 46142 JP Patent Publication No. 2002-146026 (Patent No. 3512399)

[0009] Preparation of positively charged polycaprolactone membrane materials and their biomaterial applications (Iwamatsu Kohei et al., Proceedings of the 2017 Academic Conference of the College of Science and Technology, Nihon University, pp. 1125-1126) Temperature-responsive cross-linked poly((-caprolactone)) membrane that functions near body temperature (Koichiro Uto et al., Journal of Controlled Release 110 (2006) 408-413) A novel degradable polycaprolactone networks for tissue (HaeYong Kweon et al., Biomaterials 24 (2003) 801-808)

[0010] The present invention has been made to solve the above-mentioned problems, and provides silicone elastomer particles which, when incorporated into cosmetic compositions and the like, can achieve a feel and sensation of use equal to or better than that of conventional silicone elastomer particles and which have a crosslinked structure that is active toward biodegradation; a reactive group-containing polycaprolactone compound with a specific structure that is useful as a raw material for the synthesis reaction of the silicone elastomer particles; and methods for producing the same.

[0011] Another object of the present invention is to provide applications such as cosmetic ingredients, organic resin additives, and other uses that use the silicone elastomer particles and that have an excellent feel when used, etc. Another object of the present invention is to provide cosmetic compositions that contain the silicone elastomer particles and have an excellent feel when used, etc.

[0012] Furthermore, the present invention aims to provide silicone elastomer particles, their synthetic raw materials, and uses thereof, which, in addition to having performance equal to or greater than that of conventional silicone elastomer particles, are expected to be biodegradable, thereby reducing the potential risk to the global environment, allowing for industrially sustainable and stable use, and which can be promoted as a biodegradable, eco-friendly material to users and general consumers who are concerned about the impact on the global environment.

[0013] As a result of intensive research to solve the above problems, the present inventors have found that a compound having the following structural formula (1) in a molecule: (1) {wherein n is a number ranging from 1 to 5, and Ra is —C(═O)—R １ -CR ２ =CH ２ (R １ is a carbonyl group or a divalent linking group containing one carbonyl group, and R ２The present inventors have discovered that the above-mentioned problems can be solved by using a reactive group-containing polycaprolactone compound having two or more modified polycaprolactone structures having {(a) (meth)acrylic terminal group and (b) alkenyl terminal group} represented by the formula (wherein (a) is a hydrogen atom or a methyl group) and (b) an alkenyl terminal group, and using the compound as a raw material for silicone elastomer particles. The reactive group refers to one or more reactive functional groups selected from (meth)acrylic-modified groups and alkenyl-modified groups, which are radically polymerizable or hydrosilylation reactive. In other words, the reactive group-containing polycaprolactone compound of the present invention includes both (meth)acrylic-modified polycaprolactone compounds and alkenyl-modified polycaprolactone compounds.

[0014] Similarly, the present inventors have discovered that the above-mentioned problems can be solved by silicone elastomer particles having a structure in which at least two silicon atoms within the silicone elastomer particles have been crosslinked by one or more reactions selected from the radical polymerization reaction and hydrosilylation reaction of the reactive group-containing polycaprolactone compound, more specifically, the radical polymerization reaction of a (meth)acrylic-modified polycaprolactone compound and the hydrosilylation reaction of silicon-bonded hydrogen atoms of an alkenyl-modified polycaprolactone compound, and by cosmetic ingredients, organic resin additives, cosmetics, or organic resins containing the same, and have arrived at the present invention.

[0015] When silicone elastomer particles obtained using the reactive group-containing polycaprolactone compound according to the present invention are blended into cosmetic compositions and the like, they can achieve a feel and sensation of use that is equal to or better than that of conventional silicone elastomer particles. Furthermore, by using the silicone elastomer particles according to the present invention, it is possible to provide cosmetic ingredients, organic resin additives, and other uses that contain the silicone elastomer particles. Furthermore, cosmetic compositions containing the silicone elastomer particles according to the present invention can provide cosmetics that offer excellent sensation of use.

[0016] Furthermore, the silicone elastomer particles of the present invention have a structure in which at least two silicon atoms that constitute polyorganosiloxane chain are crosslinked by a divalent organic group with a partial structure formed by the radical polymerization or hydrosilylation reaction of the reactive group-containing polycaprolactone compound of the present invention in the silicone elastomer particles, and this divalent organic group with this partial structure is active in biodegradation reaction, and in a biodegradable environment, the crosslinked structure formed between the silicon atoms in the silicone elastomer particles is at least partially cleaved, and the primary particles of the silicone elastomer particles are designed to have the property of being disintegrated with the generation of non-crosslinked polyorganosiloxane.Therefore, the silicone elastomer particles of the present invention are expected to have biodegradability, can reduce the risk to the global environment, and can be promoted as an eco-friendly material that can be used with a considerable sense of security to users and general consumers who care about the impact on the global environment.

[0017] 1 shows an image of silicone elastomer particles No. 1 (Example 5) according to the present invention observed with a digital microscope (device name: Keyence Corporation, model number VH-6000). 2 shows an image of silicone elastomer particles No. 3 (Example 7) according to the present invention observed with a digital microscope (device name: Keyence Corporation, model number VH-6000). 3 shows the results of an enzymatic degradation test of silicone elastomer particles of Examples 8, 7, and 12 according to the present invention and an existing silicone elastomer product (comparative experiment).

[0018] In this specification, the term "(meth)acrylic" means "acrylic or methacrylic," and when expressed as "(meth)acrylic-modified," it means that the modifying group may be either or both of an acrylic-modified group and a methacrylic-modified group. Similarly, the term "(meth)acryloxy" means "methacryloxy or acryloxy," and the term "(meth)acryloxy group-containing organic group" means that it may be either or both of a methacryloxy group-containing organic group and an acryloxy group-containing organic group.

[0019] [Reactive Group-Containing Polycaprolactone Compound] The reactive group-containing polycaprolactone compound according to the present invention is one or more compounds selected from (meth)acrylic-modified polycaprolactone compounds and alkenyl-modified polycaprolactone compounds. It is designed as a reactive raw material for the novel silicone elastomer particles according to the present invention, and is a component that, through its radical polymerization reaction and hydrosilylation reaction with silicon-bonded hydrogen atoms, provides a crosslinked structure within the silicone elastomer particles by a divalent organic group having a specific partial structure between at least two silicon atoms that make up the polyorganosiloxane chain.

[0020] Specifically, the reactive group-containing polycaprolactone compound of the present invention has, in the molecule, the following structural formula (1): (1) Because such compounds have two or more (meth)acrylic-modified groups or alkenyl-modified groups at their terminals, they form crosslinked structures within silicone elastomer particles by hydrosilylation or radical polymerization, and when the resulting silicone elastomer particles are used as a cosmetic ingredient, the feeling of use or touch is not impaired, and the crosslinked structure formed between the two silicon atoms is expected to be biodegradable.

[0021] Here, n in the formula represents the number of caprolactone units in the structure {—C(═O)—C ５ H １０ —O—} and is a number in the range of 1 to 5, and may be a number in the range of 1 to 3. The reactive group-containing polycaprolactone compound according to the present invention is designed as a crosslinking agent between silicon atoms in the silicone elastomer particles, and because the number of caprolactone units in each structure is relatively small and the number of repeating caprolactone units in the molecule as a whole is also relatively small, it has the advantage of not significantly impairing the feel and sensation of use that are derived from the organopolysiloxane main chain of the silicone elastomer particles.

[0022] In the formula, Ra is —C(═O)—R １ -CR ２ =CH ２where R is a (meth)acrylic or alkenyl end group represented by the formula: １ is a carbonyl group or a divalent linking group containing one carbonyl group, and is preferably a group selected from a carbonyl group (-C(=O)-), a divalent organic group containing a carbonyl group and having 1 to 20 carbon atoms, and a divalent silicon atom-containing group containing a carbonyl group. ２ is a hydrogen atom or a methyl group, which gives an acrylic-modified group, a methacrylic-modified group, and an alkenyl-modified group, respectively.

[0023] The reactive group-containing polycaprolactone compound of the present invention is a crosslinking agent between at least two silicon atoms, and therefore must have at least two reactive groups selected from reactive (meth)acrylic-modified groups and reactive alkenyl-modified groups in the molecule. Therefore, the (meth)reactive group-containing polycaprolactone compound of the present invention must have two or more of the above structures in the molecule, and may have from two to four of them. This is because polycaprolactone compounds having polyol (alcohol) hydroxyl groups at their terminals, which serve as precursors to the structures, are relatively readily available as reactive production raw materials on an industrial scale.

[0024] In the reactive group-containing polycaprolactone compound of the present invention, the number of repeating caprolactone units in each structure is relatively small, and the sum of the number of repeating caprolactone units in the molecule is preferably in the range of 2 to 20, and may be in the range of 2.5 to 15, or in the range of 3.0 to 12. If the number of repeating caprolactone units in the molecule of the reactive group-containing polycaprolactone compound exceeds the upper limit, the properties derived from the polycaprolactone structure will be strongly reflected in the resulting silicone elastomer particles, which may have an adverse effect on the feel and sensation of use of cosmetics and the like.

[0025] More specifically, the reactive group-containing polycaprolactone compound of the present invention may be a compound represented by one or more structural formulas selected from the following structural formulas (1-1) to (1-5), each of which has two, three, or four modified polycaprolactone structures represented by the following structural formula (1):

[0026] Structural formula (1-1): (1-1) Structural formula (1-2): (1-2) Structural formula (1-3): (1-3) Structural formula (1-4): (1-4) Structural formula (1-5): (1-5)

[0027] In each formula, Ra is the same group as defined above. In structural formula (1-1), m and n are each independently a number in the range of 1 to 5, m + n is a number in the range of 2 to 20, and m + n may be a number in the range of 2.5 to 15, or may be a number in the range of 3 to 10. In structural formula (1-2) or (1-3), w, x, y, and z are each independently a number in the range of 1 to 5, x + y + z is a number in the range of 3 to 20, and w + x + y + z is a number in the range of 4 to 20. Furthermore, x + y + z may be a number in the range of 3 to 7, and w + x + y + z may be a number in the range of 4 to 10. In structural formula (1-4), m and n are each independently a number in the range of 1 to 5, m + n is a number in the range of 2 to 20, and m + n may be a number in the range of 2.5 to 15, or may be a number in the range of 3 to 10. In structural formula (1-5), m and n are each independently a number ranging from 1 to 5, and m+n is a number ranging from 2 to 20. m+n may be a number ranging from 2 to 15, or may be a number ranging from 2 to 10. Furthermore, a+b may be a number ranging from 1 to 500, and a+b may be a number ranging from 2 to 350.

[0028] Such reactive group-containing polycaprolactone compounds, more specifically compounds selected from (meth)acrylic-modified polycaprolactone compounds and alkenyl-modified polycaprolactone compounds, can be obtained by reacting a precursor polycaprolactone compound having a polyol terminal structure with a (meth)acryloyl chloride compound and an alkenoyl chloride compound in the presence of a basic catalyst, or can be obtained by reacting with tetramethyldivinyldisilazane (hereinafter sometimes referred to as "vinylsilazane") in the presence of an acidic catalyst.

[0029] Specifically, the reactive group-containing polycaprolactone compound according to the present invention has, in the molecule, the following structural formula (1'): (1') (wherein n is a number in the range of 1 to 5), and a polycaprolactone compound having two or more polycaprolactone structures each having a polyol terminal structure represented by the formula Cl—C(═O)—R １ -CR ２ =CH ２ (R １ is a chemical bond between CH and C(=O) or a divalent organic group having 1 to 20 carbon atoms, and R ２ is a hydrogen atom or a methyl group) and an alkenoyl chloride compound in the presence of a basic catalyst, or further in the presence of an acid catalyst. The reaction ratio of the polycaprolactone compound to the (meth)acryloyl chloride compound, the alkenoyl chloride compound, and the vinylsilazane is such that the (meth)acryloyl chloride compound, the alkenoyl chloride compound, and the vinylsilazane are in amounts (number of moles) such that the amount of the (meth)acryloyl chloride compound, the alkenoyl chloride compound, and the vinylsilazane is 1 equivalent to a slight excess relative to the amount (number of moles) of the polyol terminal structure (—OH) of the polycaprolactone compound.

[0030] The basic catalyst usable in the reaction is not particularly limited, and may be an alkali metal salt of an inorganic base such as sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogencarbonate, etc.; an amine compound or a nitrogen-containing heterocyclic compound such as triethylamine, pyridine, dimethylaminopyridine, etc. The acidic catalyst usable in the reaction is not particularly limited, and may be trifluoromethanesulfonic acid, sulfuric acid, hydrochloric acid, etc.

[0031] The reaction may be carried out in an organic solvent, and examples of usable organic solvents include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; amides such as formamide, acetamide, N-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide, and dimethylacetamide; halogenated hydrocarbons such as methylene chloride, chloroform, 1,2-dichloroethane, chlorobenzene, bromobenzene, dichlorobenzene, benzotrifluoride, and hexafluoro-2-propanol; sulfoxides such as dimethyl sulfoxide (DMSO), diethyl sulfoxide, and benzyl phenyl sulfoxide; ethers such as diethyl ether, diisopropyl ether, dibutyl ether, tetrahydrofuran (THF), dioxane, 1,2-dimethoxyethane, and cyclopentyl methyl ether; esters such as ethyl acetate; nitriles such as acetonitrile and benzonitrile; aromatic hydrocarbons such as benzene, toluene, and xylene; and mixtures of two or more of these.

[0032] In this reaction, one or more polymerization inhibitors may be contained in the system to prevent the synthesized reactive group-containing polycaprolactone compound (e.g., a (meth)acrylic-modified polycaprolactone compound) from undergoing further radical polymerization reaction. For example, one or more selected from hindered phenol-based polymerization inhibitors, hydroquinone-based polymerization inhibitors (typically, hydroquinone monomethyl ether, MEHQ, etc.), and catechol-based polymerization inhibitors may be contained.

[0033] The reaction conditions should be appropriately selected depending on the synthesis amount, the reaction apparatus, etc., but it is preferable to dropwise add the (meth)acryloyl chloride compound, the alkenoyl chloride compound, and the vinylsilazane while stirring a mixed solution containing the polycaprolactone compound, the basic catalyst, and an optional polymerization inhibitor under a flow of inert gas such as nitrogen. After the reaction is completed, it is particularly preferable to separate the target reactive group-containing polycaprolactone compound and vinylsilazane and purify them by distilling off the unnecessary organic solvent under reduced pressure.

[0034] [Silicone Elastomer Particles] The silicone elastomer particles of the present invention, particularly their uses including as cosmetic raw materials, their production method, and cosmetic compositions and organic resins (including paints and coating agents) containing them will be described in detail below.

[0035] The silicone elastomer particles of the present invention are characterized by having a structure in which at least two silicon atoms within the silicone elastomer particles are crosslinked by one or more reactions selected from the group consisting of: (i) a radical polymerization reaction of the (meth)acrylic-modified polycaprolactone compound, which is a reactive group-containing polycaprolactone compound; and (ii) a hydrosilylation reaction of silicon-bonded hydrogen atoms of the alkenyl-modified polycaprolactone compound, which is a reactive group-containing polycaprolactone compound.

[0036] More specifically, the silicone elastomer particles of the present invention are obtained by a crosslinking reaction selected from a radical polymerization reaction and a hydrosilylation reaction, and each has the following structural characteristics.

[0037] [Radical Polymerization Reaction Type Silicone Elastomer Particles] These silicone elastomer particles are obtained by radically polymerizing an organopolysiloxane having three or more silicon-bonded radically reactive functional groups, such as (meth)acryloxy group-containing organic groups, bonded to silicon atoms within the molecule with the (meth)acrylic-modified polycaprolactone compound in the presence of a radical polymerization initiator, and are characterized in that at least two silicon-silicon bonds within the silicone elastomer particles comprise a crosslinked structure formed by a radical polymerization reaction between the terminal (meth)acrylic-modified group of the (meth)acrylic-modified polycaprolactone compound and the silicon-bonded radically reactive functional group.

[0038] [Hydrosilylation reaction-type silicone elastomer particles] These particles are obtained by subjecting an organopolysiloxane (=organohydrogenpolysiloxane) having three or more silicon-bonded hydrogen atoms in the molecule to a hydrosilylation reaction with an alkenyl-modified polycaprolactone compound in the presence of a hydrosilylation reaction catalyst, and are characterized in that at least two silicon-silicon bonds within the silicone elastomer particles comprise a crosslinked structure formed by a hydrosilylation reaction (addition reaction) between the modified group at the alkenyl end of the alkenyl-modified polycaprolactone compound and the silicon-bonded hydrogen atom.

[0039] The silicone elastomer particles of the present invention may further comprise -(R １ ２ SiO) ｎ - (wherein, R １ is an unsubstituted or halogen-substituted alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 22 carbon atoms, or a hydroxyl group, and n is a number in the range of 1 to 1000. This is a linear polysiloxane structure derived from component (A), which will be described later, and provides the silicone elastomer particles with appropriate hardness and flexibility.

[0040] In industry, R １ are each independently preferably a methyl group or a phenyl group, and n is preferably a number in the range of 50 to 800, more preferably a number in the range of 75 to 750.

[0041] The silicone elastomer particles according to the present invention are preferably produced by curing crosslinkable reactive silicone emulsion particles through a crosslinking reaction. The silicone elastomer particles of the present invention are particularly preferably silicone elastomer particles defined by their production process, and are obtained by crosslinking in water crosslinkable reactive silicone emulsion particles obtained by emulsifying in water a crosslinkable reactive silicone composition capable of crosslinking by one or more reactions selected from a radical polymerization reaction and a hydrosilylation reaction of silicon-bonded hydrogen atoms, the crosslinkable reactive silicone composition comprising at least: (A) at least one reactive organopolysiloxane selected from the following components (a1) and (a2): (a1) an organopolysiloxane having in its molecule at least three (meth)acryloxy group-containing organic groups, at least one type selected from methacryloxy group-containing organic groups and acryloxy group-containing organic groups; and (a2) an organopolysiloxane having in its molecule at least three silicon-bonded hydrogen atoms; (B) the reactive group-containing polycaprolactone compound; and (C) one or more curing agents selected from a radical polymerization initiator and a hydrosilylation reaction catalyst.

[0042] Furthermore, silicone elastomer particles obtained through such a manufacturing process may be able to further improve the appearance, spreadability, and feel of the cosmetic, particularly when used as a cosmetic ingredient, and particles obtained by this manufacturing method tend to be more suitable for solving the problems of the present invention. Thus, one of the preferred modes for achieving the technical effects of the present invention can and appropriately be defined by the manufacturing process.

[0043] The silicone elastomer particles according to the present invention are not particularly limited in their average primary particle size, but from the standpoints of imparting a smooth feel and comfortable sensation to cosmetics, not causing poor appearance, and ensuring storage stability and blending stability as a cosmetic ingredient, the average particle size measured by laser diffraction scattering is preferably in the range of 0.5 to 20 μm, and more preferably 0.5 to 15 μm. The particle size of the silicone elastomer particles can be controlled by the crushing / classification process of the crosslinked reactive silicone emulsion particles and the resulting silicone elastomer particles.

[0044] The shape of the silicone elastomer particles according to the present invention may be, for example, spherical, true spherical, ellipsoidal, or irregular, with spherical and true spherical shapes being particularly preferred. Spherical silicone elastomer particles can be easily obtained by preparing the silicone elastomer particles in the form of an aqueous suspension, as described below, and drying them using a vacuum dryer, a hot air circulation oven, or a spray dryer.

[0045] Furthermore, in the present invention, when the crosslinkable silicone composition used to form the silicone elastomer particles is cured into a sheet, it is preferable that the JIS-A hardness, as measured using a JIS-A hardness scale specified in JIS K6301, be in the range of 10 to 80. When the JIS-A hardness of the rubber sheet obtained by curing the crosslinkable silicone composition into a sheet falls within this range, the resulting silicone elastomer particles are likely to be sufficiently suppressed in aggregation and to be rich in fluidity, dispersibility, silky feel, smoothness, and softness. Furthermore, by selecting this JIS-A hardness, it is possible to design or predict, to a certain extent, the feel, texture, and handling properties of the silicone elastomer particles when incorporated into cosmetics, and it is also possible to improve stress relaxation properties when incorporated into organic resins. When the silicone elastomer particles of the present invention are used as a cosmetic ingredient or a stress relaxation agent for organic resins, it is particularly preferable to use silicone elastomer particles having a JIS-A hardness in the range of 30 to 80, particularly 50 to 80.

[0046] Optionally, the silicone elastomer particles of the present invention may have a structure in which the surface thereof is partially or entirely coated with one or more materials selected from organopolysiloxane resins, silica, and other silicone elastomer particles, which may be expected to further reduce cohesion, control oil absorption, improve feel, etc.

[0047] Optionally, the silicone elastomer particles of the present invention may have a mesoporous structure having fine pores.

[0048] Optionally, the silicone elastomer particles of the present invention may contain an oil that is liquid at 40° C. The oil can be easily incorporated into the silicone elastomer particles by emulsifying it together with the cross-linking reactive silicone composition described below, and the inclusion of the oil can be expected to further reduce cohesion, control oil absorption, improve feel, and the like.

[0049] Optionally, the silicone elastomer particles of the present invention may further have a structure in which at least two silicon atoms constituting the particles are crosslinked by a silalkylene group having 2 to 20 carbon atoms, formed by a hydrosilylation reaction involving an alkenyl group having 2 to 20 carbon atoms. These structures can be easily achieved by using an alkenyl group-containing organopolysiloxane, an organohydrogenpolysiloxane, and a hydrosilylation-reactive catalyst in combination. Furthermore, by using an alkenyl group having 4 or more carbon atoms, such as a hexenyl group, in addition to the silalkylene structure, further reduction in cohesion, control of oil absorption, and improvement in feel may be expected. However, when biodegradability is the primary objective, it is preferable that the silicone elastomer particles of the present invention are substantially free of a structure containing a silalkylene group.

[0050] [Crosslinking Reactive Silicone Composition Used to Form Silicone Elastomer Particles] More specifically, the silicone elastomer particles of the present invention can be obtained by crosslinking (curing) a crosslinking reactive silicone composition containing the following components through one or more reactions selected from a radical polymerization reaction and a hydrosilylation reaction of silicon-bonded hydrogen atoms: (A) at least one reactive organopolysiloxane selected from the following components (a1) and (a2): (a1) an organopolysiloxane having in its molecule at least three (meth)acryloxy group-containing organic groups, at least one of which is selected from methacryloxy group-containing organic groups and acryloxy group-containing organic groups, and (a2) an organopolysiloxane having in its molecule at least three silicon-bonded hydrogen atoms, (B) the reactive group-containing polycaprolactone compound, and (C) one or more curing agents selected from a radical polymerization initiator and a hydrosilylation reaction catalyst.

[0051] The crosslinking (curing) reaction is one or more reactions selected from a radical polymerization reaction and a hydrosilylation reaction, and although these reactions may proceed simultaneously, it is preferable to select one of them to form the silicone elastomer particles from the standpoint of reaction control. That is, the composition may be a composition containing the following two reaction types and components:

[0052] [Radical Polymerization Reaction-Type Silicone Elastomer Particle Forming Composition] A crosslinkable reactive silicone composition comprising: (a1) an organopolysiloxane having, in the molecule, at least three (meth)acryloxy group-containing organic groups, each of which is at least one type selected from methacryloxy group-containing organic groups and acryloxy group-containing organic groups; (B1) the (meth)acrylic-modified polycaprolactone compound, which is a reactive group-containing polycaprolactone compound; and (c1) a radical polymerization initiator.

[0053] [Hydrosilylation reaction-type silicone elastomer particle-forming composition] A crosslinkable reactive silicone composition comprising: (a2) an organopolysiloxane having at least three silicon-bonded hydrogen atoms in the molecule; (B2) the alkenyl-modified polycaprolactone compound described above, which is a reactive group-containing polycaprolactone compound; and (c2) a hydrosilylation reaction catalyst.

[0054] Component (a1) is an organopolysiloxane having at least three (meth)acryloxy group-containing organic groups in the molecule. Its structure is not particularly limited and may be one or more structures selected from linear, cyclic, network, and partially branched linear structures, with linear organopolysiloxanes being particularly preferred. Furthermore, the viscosity of component (a) is preferably such that the crosslinkable composition can be dispersed in water. Specifically, the viscosity is preferably within the range of 20 to 100,000 mPa·s at 25°C, and more preferably within the range of 20 to 10,000 mPa·s.

[0055] From the standpoints of the feel, dispersibility, and handling ease of the silicone elastomer particles, component (a1) is preferably a linear organopolysiloxane in which the content of dimethylsiloxane units represented by the formula -(CH3)2SiO- is 90 mol% or more of all siloxane units other than terminal siloxane units of the molecule. Similarly, from the standpoint of improving the oil absorption properties of the resulting silicone elastomer particles, cyclic or linear organopolysiloxanes with low degrees of polymerization (3 to 20) may be removed in advance from component (a1) by stripping or other methods.

[0056] Furthermore, when component (a1) is a linear organopolysiloxane, if the silicone elastomer particles according to the present invention are placed in a biodegradable environment, the silicone elastomer particles are easily decomposed into non-crosslinked linear organopolysiloxanes when the crosslinked structure is cleaved and the silicone elastomer particles are disintegrated, which has the advantage of making it easier to reduce environmental load and environmental risk.

[0057] Since component (a1) forms a crosslinked structure through a radical reaction with component (B1), it must contain an average of at least three (meth)acryloxy group-containing organic groups per molecule. If the molecule contains an average of two or fewer (meth)acryloxy group-containing organic groups, a sufficient crosslinked structure may not be formed, and practical silicone elastomer particles may not be obtained.

[0058] More specifically, the (meth)acryloxy group-containing organic group is a (meth)acryloxy group bonded to a silicon atom via a divalent organic group, and is represented by the formula: —R ２ -O-C(=O)-C(R ３ ) = CH ２ {In the formula, R ２ is an alkylene group having 1 to 20 carbon atoms or (CH ２ ) ｐ -Si(CH ３ ) ２ —O—Si(CH ３ ) ２ - (CH ２ ) ｑ (wherein p and q are each a number ranging from 1 to 20), and R ３is a hydrogen atom or a methyl group.}.

[0059] R in the formula ２ The alkylene group represented by (CH ２ ) ｐ -Si(CH ３ ) ２ —O—Si(CH ３ ) ２ - (CH ２ ) ｑ The divalent linking group represented by the formula (I) is a divalent linking group having a siloxane converter structure, and industrially, examples thereof include linking groups in which p and q are each independently a number from 3 to 6.

[0060] Component (a1) is preferably a linear organopolysiloxane represented by the following structural formula:

[0061] In formula (1), R １１ are each independently an unsubstituted or halogen-substituted alkyl group having 1 to 20 carbon atoms (e.g., methyl group), an aryl group having 6 to 22 carbon atoms (e.g., phenyl group), or a hydroxyl group, and are preferably a methyl group or a phenyl group industrially. ａ is the above-mentioned (meth)acryloxy group-containing organic group, and is particularly preferably a (meth)acryloxy group bonded to a silicon atom via the above-mentioned alkylene group or a divalent linking group having a siloxane converter structure. １１ or R ａ where m is a number of 1 or more, and n is a number of 1 or more. However, component (a) has at least three R ａ Since the (meth)acryloxy group-containing organic group represented by the formula (I) is contained, when m=1, R is R ａ That is, the linear organopolysiloxane represented by the above structural formula has R at one end and side chain, only at the side chain, or at both end and side chain of the siloxane molecule. ａand preferably an organopolysiloxane having a (meth)acryloxy group-containing organic group represented by the formula: and containing at least three (meth)acryloxy group-containing organic groups in the molecule.

[0062] m+n is the degree of siloxane polymerization of the linear organopolysiloxane molecule excluding the terminal siloxane structure, and from the standpoints of handling as a raw material, emulsification properties, and disintegration into fine linear siloxane molecules upon biodegradation, m+n is preferably in the range of 10 to 800, more preferably 20 to 600, and particularly preferably 30 to 500. Furthermore, it is particularly preferable that m+n be a number that results in a viscosity of component (a) of 20 to 10,000 mPa s at 25°C.

[0063] Component (a2) is an organopolysiloxane component that is crosslinked by component (B2) via a hydrosilylation reaction, and is characterized by having at least three silicon-bonded hydrogen atoms in the molecule. There are no particular restrictions on the bonding positions of these hydrogen atoms in the molecule.

[0064] Examples of organic groups other than hydrogen atoms that are bonded to silicon atoms contained in component (a2) include alkyl groups such as methyl, ethyl, propyl, butyl, and octyl groups, with methyl being preferred.Furthermore, examples of the molecular structure of the organohydrogenpolysiloxane of component (a2) include linear, branched, and branched cyclic structures, or a combination of one or more of these.The number of silicon-bonded hydrogen atoms in one molecule is the average value for all molecules.

[0065] In particular, when component (a2) is a linear organopolysiloxane (organohydrogenpolysiloxane), when the silicone elastomer particles according to the present invention are placed in a biodegradable environment, the cross-linked structure is cleaved and the silicone elastomer particles are disintegrated, which facilitates decomposition into non-cross-linked linear organopolysiloxanes, thereby providing the advantage of facilitating reduction in environmental load and environmental risk.

[0066] The viscosity of component (a2) at 25°C is 1 to 1,000 mPa·s, and preferably 5 to 500 mPa·s. If the viscosity of component (b) at 25°C is less than 1 mPa·s, component (a2) will be more likely to volatilize from the crosslinkable composition containing it, while if it exceeds 1,000 mPa·s, the curing time of the crosslinkable composition containing such component (a2) will be longer or this may cause poor curing. The component (a2) is not particularly limited, but examples thereof include a dimethylsiloxane-methylhydrogensiloxane copolymer both ends of which are capped with trimethylsiloxy groups, a dimethylsiloxane-methylhydrogensiloxane copolymer both ends of which are capped with dimethylhydrogensiloxy groups, a dimethylpolysiloxane both ends of which are capped with dimethylhydrogensiloxy groups, a methylhydrogenpolysiloxane both ends of which are capped with trimethylsiloxy groups, a cyclic methylhydrogenpolysiloxane, and a cyclic methylhydrogensiloxane-dimethylsiloxane copolymer.

[0067] Here, the molar ratio (=reaction ratio in the hydrosilylation reaction) of the carbon-carbon double bonds (Alk) contained in the alkenyl-modified polycaprolactone compound (component (B2)) to the silicon-bonded hydrogen atom content (H) of component (a2) (H / Alk) is preferably in the range of 0.7 to 1.2. The lower limit of H / Alk is preferably 0.80 or more, 0.85 or more, 0.90 or more, or 0.95 or more, and the upper limit is 1.15 or less, more preferably 1.10 or less, or 1.05 or less. If the upper limit of H / Alk exceeds the above-mentioned value, unreacted silicon-bonded hydrogen atoms are likely to remain after the reaction. Conversely, if the upper limit of H / Alk is less than the above-mentioned value, unreacted silicon-bonded hydrogen atoms and their alkenyl-modified terminal groups are likely to remain after the reaction. Because these are curing reactive groups, if a large amount remains in the particles, they can cause crosslinking reactions between particles over time, resulting in aggregation and poor dispersion of the obtained oil-containing silicone elastomer particles, and if reactive hydrogen atoms remain, they can cause the generation of flammable hydrogen gas over time. Particularly preferably, when the H / Alk value is 0.9 to 1.1, and especially close to 1.0, the curing reactive groups are completely consumed, the crosslinking reaction is terminated, and aggregation between particles over time can be effectively suppressed.

[0068] Component (B) is a reactive group-containing polycaprolactone compound (specifically, a compound selected from the aforementioned (meth)acrylic-modified polycaprolactone compound and alkenyl-modified polycaprolactone compound), which serves as a crosslinking agent for component (A) that imparts the characteristic crosslinked structure of the silicone elastomer particles of the present invention, and is also a radically polymerizable monomer component that itself forms a polymer or copolymer structure by radical polymerization. Whether the crosslinked moiety is a hydrosilylation reaction type or a radical polymerization type, it does not significantly impair the feel and usability of the resulting silicone elastomer particles, and is active in biodegradable reactions, so that in a biodegradable environment, the crosslinked structure formed between silicon atoms in the silicone elastomer particles at least partially cleaves, causing the primary particles of the silicone elastomer particles to disintegrate, generating non-crosslinked polyorganosiloxanes. Here, if component (A) is a linear polyorganosiloxane as described above, the silicone elastomer particles are easily broken down into linear polyorganosiloxane molecules by the biodegradable reaction, and unlike macroplastics, they are broken down into fine liquid components rather than solid powders with minute particle sizes. This makes it less likely to cause problems such as bioaccumulation through the food chain or accumulation / deposition in the environment, and is expected to have less impact or burden on the global environment.

[0069] The amount of component (B) used must be selected as follows, depending on the type of component (A) and the crosslinking reaction to be performed to obtain the silicone elastomer particles of the present invention.

[0070] When silicone elastomer particles are formed by the radical polymerization reaction of the aforementioned components (a1) and (B1), the ratio of the amount of component (B1) to the amount of (meth)acryloxy group-containing organic groups in component (a1) is preferably within the range of 0.5 to 30, more preferably 1 to 20, more preferably 3 to 15, and particularly preferably 5 to 10. When the amount of component (B) used is within the above range, a crosslinked structure derived from the (meth)acrylic-modified polycaprolactone compound with an appropriate average length is obtained between the polyorganosiloxane structures, thereby realizing appropriate hardness and a smooth surface state with low tackiness, and improving the feel and usability of the particles. On the other hand, if the amount of component (B) used is less than the above lower limit, crosslinking may be insufficient. Furthermore, if the amount of component (B) used exceeds the above upper limit, emulsion breakdown or the like may occur easily during the curing reaction, and silicone elastomer particles may not be obtained.

[0071] When silicone elastomer particles are formed by the hydrosilylation reaction of the aforementioned components (a2) and (B2), the amount of component (B2) used is preferably designed so that the molar ratio of the carbon-carbon double bond (Alk) contained in the alkenyl-modified terminal group to the silicon-bonded hydrogen atom content (H) of component (a2) (=reaction ratio in the hydrosilylation reaction), H / Alk, falls within the above-mentioned range.

[0072] Component (C) is a curing agent, and is selected from (c1) a radical polymerization initiator and (c2) a hydrosilylation reaction catalyst, depending on the selection of component (A) and the reaction system.

[0073] Component (c1) is a radical initiator that promotes the radical polymerization or radical copolymerization reaction of components (a1) and (B1). Examples of such radical initiators include conventional compounds commonly used in radical polymerization methods, such as azo compounds such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylbutyronitrile), and 2,2'-azobis(2,4-dimethylvaleronitrile); organic peroxides such as benzoyl peroxide, lauroyl peroxide, tert-butyl peroxybenzoate, tert-butylperoxy-2-ethylhexanoate, and tert-hexylperoxy-2-ethylhexanoate; and persulfates such as potassium persulfate, sodium persulfate, and ammonium persulfate. These radical initiators may be used alone or in combination.

[0074] The amount of radical initiator (c1) used is preferably in the range of 0.1 to 5 parts by mass per 100 parts by mass of the combined total of components (a1) and (B1). In particular, when component (c1) is a water-soluble persulfate such as potassium persulfate, it has the advantage of being extremely easy to add and react with, especially when crosslinking in water crosslinkable silicone emulsion particles obtained by emulsifying a crosslinkable silicone composition prepared by a radical polymerization reaction in water. Furthermore, when completing the radical polymerization reaction, it is particularly preferable to add aminomethylpropanediol or the like in the range of 0.1 to 5 parts by mass for the purpose of terminating the reaction and neutralizing the solution to adjust the pH.

[0075] The timing of adding component (c1) to the crosslinkable composition can be selected depending on the method for forming the silicone elastomer particles, and it may be added to the composition in advance, or component (a1) or component (B) may be supplied from different spray lines and component (c1) may be added to either one of them and mixed during spraying. The silicone elastomer particles of the present invention are preferably prepared via an aqueous suspension formed by emulsification in water, and component (c1) may be added to the crosslinkable silicone composition in advance, or an emulsion containing component (c1) may be added separately to water.

[0076] During the polymerization reaction of the crosslinkable silicone composition, a chain transfer agent can be optionally added. Specific examples of this chain transfer agent include mercapto compounds such as 2-mercaptoethanol, butyl mercaptan, n-dodecyl mercaptan, 3-mercaptopropyltrimethoxysilane, and polydimethylsiloxane having a mercaptopropyl group; and halides such as methylene chloride, chloroform, carbon tetrachloride, butyl bromide, and 3-chloropropyltrimethoxysilane.

[0077] Optionally, in order to adjust the particle hardness during the polymerization reaction of the crosslinkable silicone composition, a modified polycaprolactone compound having a (meth)acrylic end-modified group and an alkenyl end-modified group at one end may be used in combination. An example of such a (meth)acrylic end-modified compound is Plaxel FM1 manufactured by Daicel Corporation.

[0078] Component (c2) is a hydrosilylation catalyst that promotes the addition reaction (hydrosilylation reaction) between the carbon-carbon double bonds contained in the (meth)acrylic terminal groups present in the crosslinkable composition and silicon-bonded hydrogen atoms. Preferred hydrosilylation catalysts are those containing platinum-based metals, and specific examples include chloroplatinic acid, alcohol-modified chloroplatinic acid, olefin complexes of chloroplatinic acid, complexes of chloroplatinic acid and ketones, complexes of chloroplatinic acid and vinylsiloxanes, platinum tetrachloride, platinum fine powder, solid platinum supported on an alumina or silica carrier, platinum black, olefin complexes of platinum, alkenylsiloxane complexes of platinum, carbonyl complexes of platinum, and platinum catalysts containing these platinum-based catalysts in powders of thermoplastic organic resins such as methyl methacrylate resins, polycarbonate resins, polystyrene resins, and silicone resins. In particular, platinum alkenylsiloxane complexes such as a complex of chloroplatinic acid and divinyltetramethyldisiloxane, a complex of chloroplatinic acid and tetramethyltetravinylcyclotetrasiloxane, a platinum divinyltetramethyldisiloxane complex, and a platinum tetramethyltetravinylcyclotetrasiloxane complex are preferably used. Note that non-platinum metal catalysts such as iron, ruthenium, and iron / cobalt may also be used as catalysts for promoting the hydrosilylation reaction.

[0079] The amount of component (c2) added to the crosslinkable composition may be any catalytic amount, and typically, the amount is preferably such that the amount of platinum-based metal contained in component (c2) is in the range of 1 to 1,000 ppm, more preferably in the range of 5 to 500 ppm, relative to the total mass of the crosslinkable composition. The amount of platinum metal in the silicone elastomer particles may also be reduced by the method proposed by the present inventors in JP 2014-122316 A.

[0080] The timing of adding component (c2) to the crosslinkable composition can be selected depending on the method for forming the silicone elastomer particles, and it may be added to the composition in advance, or component (a2) or component (B) may be supplied from different spray lines and component (c2) may be added to either one of them and mixed during spraying. The oil-containing silicone elastomer particles of the present invention are preferably prepared via an aqueous suspension formed by emulsification in water, and component (c2) may be added in advance to the crosslinkable silicone composition, or a separate emulsion containing component (c2) may be added to water.

[0081] The crosslinkable silicone composition may contain a cure retarder, typically a hydrosilylation reaction inhibitor. Examples of such cure retarders include acetylene compounds, enyne compounds, organic nitrogen compounds, organic phosphorus compounds, and oxime compounds. Specific compounds include alkyne alcohols such as 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, 3-methyl-1-pentyn-3-ol, 2-phenyl-3-butyn-2-ol, and 1-ethynyl-1-cyclohexanol (ETCH); 3-methyl-3-trimethylsiloxy-1-butyne, 3-methyl-3-trimethylsiloxy-1-pentyne, 3,5-dimethyl-3-trimethylsiloxy-1-hexyne, 3-methyl-3-penten-1-yne; and 3,5-dimethyl-3-hexen-1-yne and other ene-yne ​​compounds; and alkenylsiloxanes such as 1-ethynyl-1-trimethylsiloxycyclohexane, bis(2,2-dimethyl-3-butynoxy)dimethylsilane, methyl(tris(1,1-dimethyl-2-propynyloxy))silane, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, and 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane. The amount added is within a range of 0.001 to 5 parts by mass per 100 parts by mass of component (a), but can be appropriately determined depending on the type of cure retarder used, the properties and amount of the hydrosilylation reaction catalyst used, and other factors.

[0082] The cross-linking reactive silicone composition may contain one or more polymerization inhibitors from the standpoint of preventing unintended side reactions. For example, it may contain one or more selected from hindered phenol-based polymerization inhibitors, hydroquinone-based polymerization inhibitors, and catechol-based polymerization inhibitors. The amount used can be selected appropriately, but the total concentration of the polymerization inhibitors relative to the sum of the components (A) to (C) is preferably 50 ppm by mass or less, and more preferably 30 ppm by mass or less.

[0083] The crosslinkable silicone composition may contain components other than those described above, provided that the technical effects of the present invention are not impaired. For example, the crosslinkable silicone composition may contain organic solvents such as aliphatic hydrocarbons such as n-hexane, cyclohexane, and n-heptane; aromatic hydrocarbons such as toluene, xylene, and mesitylene; ethers such as tetrahydrofuran and dipropyl ether; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; antioxidants such as phenols, quinones, amines, phosphorus compounds, phosphites, sulfur compounds, and thioether compounds; light stabilizers such as triazoles and benzophenones; flame retardants such as phosphate esters, halogen compounds, phosphorus compounds, and antimony compounds; one or more antistatic agents such as cationic surfactants, anionic surfactants, and nonionic surfactants; dyes; pigments.

[0084] The silicone elastomer particles of the present invention may optionally further have (i) a structure in which the surface is partially or entirely coated with one or more selected from organopolysiloxane resins, silica, and other silicone elastomer particles; (ii) a mesoporous structure; (iii) a structure containing an oil that is liquid at 40°C; and (iv) a structure crosslinked by silalkylene groups having 2 to 20 carbon atoms, and any components that impart these structures may be used in combination. Furthermore, in consideration of biodegradation, a biodegradable oil such as olive oil may be contained.

[0085] [Hardness of Silicone Elastomer] While the hardness of silicone elastomer particles cannot be measured directly, it can be measured indirectly by curing the crosslinkable silicone composition used to form the silicone elastomer particles, which is the raw material for the silicone elastomer particles. Specifically, the crosslinkable reactive silicone composition can be cured into a sheet without being emulsified in water, and the hardness of the silicone elastomer sheet can be measured using a JIS A hardness scale as specified in JIS K6301. The hardness of the silicone elastomer according to the present invention varies depending on the type of crosslinkable silicone composition, the amount of components (a) and (b) used, and the crosslink density, but is preferably in the range of 10 to 80. Other preferred hardness values ​​are as described above.

[0086] [Formation of Silicone Elastomer Particles and Method for Manufacturing The Same] The method for manufacturing silicone elastomer particles according to the present invention includes a step of curing cross-linked reactive silicone emulsion particles obtained by emulsifying the cross-linkable silicone composition used to form the silicone elastomer particles in water in the presence of a curing agent (C) to obtain spherical silicone elastomer particles.

[0087] More specifically, the silicone elastomer particles according to the present invention can be prepared preferably by a production method comprising the following steps (I) and (II): Step (I): A step of emulsifying in water (A) at least one reactive organopolysiloxane selected from the aforementioned components (a1) and (a2), (B) a reactive group-containing polycaprolactone compound, and (C) one or more curing agents selected from radical polymerization initiators and hydrosilylation reaction catalysts to form crosslinkable reactive silicone emulsion particles, and Step (II): A step of curing the crosslinkable reactive silicone emulsion particles obtained in step (I) in the presence of the curing agent (C) to obtain silicone elastomer particles.

[0088] The crosslinkable silicone composition used to form the silicone elastomer particles can be mixed uniformly using mechanical force such as a mixer. In addition, considering biodegradability, it can also be diluted with a biodegradable oil such as olive oil.

[0089] In this method, silicone elastomer particles can be obtained by emulsifying the above-mentioned crosslinkable silicone composition in an aqueous surfactant solution and curing it. Furthermore, particle size can be easily adjusted by adjusting the emulsion particle size. Examples of surfactants include nonionic, anionic, cationic, betaine, and water-soluble polymers such as polyvinyl alcohol. The particle size of the resulting silicone elastomer particles varies depending on the type and content of the surfactant. To prepare small-sized silicone elastomer particles, the amount of surfactant added is preferably within the range of 0.5 to 50 parts by weight per 100 parts by weight of the crosslinkable silicone composition.

[0090] To uniformly disperse the crosslinkable silicone composition in water in the form of crosslinkable reactive silicone emulsion particles, it is preferable to use an emulsifier, such as a homomixer, paddle mixer, Henschel mixer, homodisper, colloid mill, propeller agitator, homogenizer, in-line continuous emulsifier, ultrasonic emulsifier, or vacuum kneader.

[0091] The aqueous dispersion of crosslinkable silicone emulsion particles prepared by the above method can then be heated or left at room temperature to cure the crosslinkable silicone emulsion particles in the aqueous dispersion, thereby preparing an aqueous dispersion of silicone elastomer particles. When such an aqueous dispersion is heated, from the standpoint of hydrosilylation reactivity or radical polymerization reactivity, the heating temperature is preferably 100°C or less, and particularly preferably 10 to 95°C. Methods for heating the aqueous dispersion containing crosslinkable silicone emulsion particles include, for example, directly heating the aqueous dispersion or adding the aqueous dispersion to hot water. The liquid crosslinkable silicone emulsion particles cure in water through the crosslinking reaction, forming an aqueous dispersion of silicone elastomer particles.

[0092] The silicone elastomer particles of the present invention thus obtained can be used as an aqueous dispersion (aqueous suspension) as is. In particular, they may be used as a cosmetic raw material in the form of this aqueous suspension, and this is preferred. When blended into cosmetics that use an aqueous solution as a dispersion medium (e.g., hair cosmetics), blending the silicone elastomer particles of the present invention as an aqueous dispersion may facilitate uniform dispersion of the silicone elastomer particles, thereby achieving the desired performance and feel.

[0093] Preferably, the silicone elastomer particles of the present invention can be isolated by removing water from an aqueous dispersion of silicone elastomer particles. Methods for removing water from the aqueous dispersion include, for example, drying using a vacuum dryer, a hot air circulation oven, or a spray dryer. The heating and drying temperature of the spray dryer must be appropriately set based on the heat resistance and crosslinking temperature of the silicone elastomer particles. To prevent secondary aggregation of the resulting microparticles, it is preferable to control the temperature of the silicone elastomer particles below their glass transition temperature. The silicone elastomer particles thus obtained can be recovered using a cyclone, a bag filter, or the like. As a pretreatment for this operation, the dispersion may be concentrated by methods such as thermal dehydration, filtration, centrifugation, and decantation, and, if necessary, the dispersion may be washed with water.

[0094] The silicone elastomer particles of the present invention may be subjected to a surface treatment as needed, which may further improve the aggregation suppression effect of the silicone elastomer particles of the present invention. Furthermore, surface treatment with other known hydrophilic or hydrophobic treatment agents may also be performed. Optionally, as described above, the obtained silicone elastomer particles may be further coated in part or in whole with inorganic fine particles such as silica, silicone resin, or the like. Furthermore, the obtained silicone elastomer particles may be crushed or disintegrated using mechanical force as needed, or may be classified using known techniques.

[0095] [Cosmetic Raw Materials and Cosmetic Compositions] The silicone elastomer particles of the present invention are useful as cosmetic raw materials. When blended into cosmetic compositions and the like, they are soft and have an outstanding effect of improving the feel and sensation of use of cosmetics and the like, and are remarkably easy to handle as a cosmetic raw material and have excellent storage stability and incorporation stability into systems.

[0096] In particular, the silicone elastomer particles of the present invention have the advantages of being superior in feel and texture compared to known silicone particles, offering a high degree of freedom in formulation design, and when incorporated into cosmetics, not absorbing oily ingredients over time to cause thickening or a change in feel, and when applied to skin or hair, suppressing the oiliness and stickiness of the cosmetics, imparting smooth spreadability and a soft and moist feel, and improving compatibility with the skin, resulting in an excellent feel when used.In addition, when used in combination with UV protection ingredients, the silicone elastomer particles of the present invention may be able to improve the UV protection effect of cosmetics without impairing the feel and texture of the cosmetics compared to other powders or existing silicone elastomer particles.

[0097] Furthermore, the silicone elastomer particles of the present invention have performance equal to or better than that of conventionally known silicone elastomer particles, but are active in biodegradable reactions, and in a biodegradable environment, the cross-linked structure formed between silicon atoms in the silicone elastomer particles at least partially cleaves, and the primary particles of the silicone elastomer particles are disintegrated, generating non-cross-linked polyorganosiloxanes, so they are a material with low risk and environmental load to the global environment.Furthermore, they can be used in place of conventionally known silicone elastomer particles, and are extremely versatile.

[0098] Cosmetic compositions containing the silicone elastomer particles of the present invention are not particularly limited in type, but examples include cleansing cosmetics such as soap, body shampoo, and facial cleanser; basic cosmetics such as lotions, creams, emulsions, and packs; base makeup cosmetics such as powder and foundation; eyebrow cosmetics such as lipstick, blusher, eye shadow, eyeliner, and mascara; makeup cosmetics such as nail polish; hair cosmetics such as shampoo, hair rinse, hair styling products, hair growth agents, hair care products, and hair dyes; aromatic cosmetics such as perfumes and eau de colognes; toothpaste; bath additives; and specialty cosmetics such as depilatories, shaving lotions, antiperspirants, deodorants, and sunscreens. These cosmetic compositions may be formulated in aqueous liquid, oily liquid, emulsion, cream, foam, semi-solid, solid, or powder form. These cosmetic compositions can also be used as a spray.

[0099] In these cosmetic compositions, the content of the silicone elastomer particles is preferably within the range of 0.5 to 99.0% by mass, and particularly preferably within the range of 1.0 to 95% by mass, because if the content of the silicone elastomer particles exceeds the upper limit of the range, the cosmetic effect is lost, and if it is below the lower limit of the range, it is difficult to improve the feel of use of the cosmetic composition.

[0100] The silicone elastomer particles of the present invention can be used to replace part or all of the silicone particles in cosmetic compositions (particularly the formulation examples) containing silicone particles (such as silicone rubber powder) or silicone composite particles proposed in JP-A-07-316014, WO 2017 / 191798, JP-A-02-243612, JP-A-2011-105663, JP-A-2011-168634, JP-A-2011-102354, and JP-A-2014-122316, and may further improve the usability and production efficiency of the cosmetic compositions proposed in these patent documents. Needless to say, examples of cosmetic compositions containing silicone particles (such as silicone rubber powder) or silicone composite particles that can be blended with the silicone elastomer particles of the present invention are not limited to those described above. It is also possible to design formulations in which part or all of the silicone particle components in commercially available cosmetics are replaced with the silicone elastomer particles of the present invention using techniques commonly used by those skilled in the art.

[0101] Furthermore, the silicone elastomer particles of the present invention can be used to replace part or all of the silicone particles in the applications and formulations of cosmetic compositions disclosed in the above patent documents, etc., and such uses are encompassed within the scope of the present invention. For example, the silicone elastomer particles of the present invention may be used in combination with optional ingredients such as a cosmetic medium (aqueous medium or oily medium), an oily medium (including oils and volatile oils), water, colorants, pigments, UV protection ingredients, alcohols, water-soluble polymers, film-forming agents, oils, oil-soluble gelling agents, organically modified clay minerals, surfactants, resins, salts, moisturizers, preservatives, antibacterial agents, antioxidants, pH adjusters, chelating agents, cooling agents, anti-inflammatory agents, skin-beautifying ingredients (skin-whitening agents, cell activators, agents for improving rough skin, blood circulation promoters, skin astringents, antiseborrheic agents, etc.), vitamins, amino acids, nucleic acids, hormones, inclusion compounds, etc., physiologically active substances, active pharmaceutical ingredients, fragrances, etc., by selecting the same methods and quantitative ranges as those disclosed in International Patent Publication WO2017 / 191798, and are preferred.

[0102] In particular, the silicone elastomer particles of the present invention are superior in usability, feel, handling, storage stability, dispersibility, and high oil absorption properties to those of conventionally known silicone particles, silsesquioxane-coated silicone composite particles, and oil-containing silicone particles, and therefore can achieve particularly favorable appearance, usability, etc. in the following: (1) cosmetic compositions and formulations containing an oily medium (oily cosmetic ingredient) such as an oily agent, (2) cosmetic compositions and formulations containing a lipophilic UV protection component (e.g., octyl paramethoxycinnamate, etc.), and (3) cosmetic compositions and formulations containing an inorganic powder such as a colorant or pigment. These specific formulations will be described in more detail in the examples and subsequent sections.

[0103] In addition, because the silicone elastomer particles of the present invention allow for easy design of aqueous dispersions, they offer excellent formulation design freedom and blend stability, even in aqueous cosmetic compositions and formulations, making it possible to achieve a favorable feel when used. Specific formulations for these will be described in more detail in the examples and subsequent sections.

[0104] The cosmetic preparation of the present invention can be easily produced by simply uniformly mixing the cosmetic raw material of the present invention as described above with other cosmetic raw materials. Various mixing and kneading devices commonly used in the production of cosmetics can be used as mixing means. Examples of such devices include a homomixer, paddle mixer, Henschel mixer, homodisper, colloid mixer, propeller agitator, homogenizer, in-line continuous emulsifier, ultrasonic emulsifier, and vacuum kneader.

[0105] [Organic Resin Additives and Organic Resins, Paints, and Coating Agents] The silicone elastomer particles of the present invention have the above-mentioned properties, making them extremely useful as organic resin additives. Specifically, the silicone elastomer particles of the present invention have excellent uniform dispersibility in organic resins and, if desired, excellent stress relaxation properties, and are less likely to aggregate even after long-term storage, resulting in significantly excellent handling and storage stability. Furthermore, the members, paint films, or coating films obtained by curing organic resins containing the silicone elastomer particles have improved flexibility (including the softness of the coating layer), durability, and adhesion and conformability to substrates, and are particularly excellent in flexibility and thermal shock resistance, making them extremely useful as high-performance organic resins, paints, or coating agents used in electronic materials.

[0106] [Organic Resin] Suitable examples of organic resins containing the silicone elastomer particles of the present invention include curable organic resin compositions and thermoplastic resins. Of these, curable resins are suitable for electronic materials such as semiconductor substrates. More specifically, examples of curable organic resin compositions include phenolic resins, formaldehyde resins, xylene resins, xylene-formaldehyde resins, ketone-formaldehyde resins, furan resins, urea resins, imide resins, melamine resins, alkyd resins, unsaturated polyester resins, aniline resins, sulfone-amide resins, silicone resins, epoxy resins, and copolymer resins of these resins. Two or more of these curable resins can also be combined. In particular, the curable resin is preferably at least one selected from the group consisting of epoxy resins, phenolic resins, imide resins, and silicone resins. The epoxy resin may be any compound containing a glycidyl group or an alicyclic epoxy group, and examples thereof include o-cresol novolac type epoxy resins, phenol novolac type epoxy resins, biphenyl type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, dicyclopentadiene type epoxy resins, naphthalene type epoxy resins, anthracene type epoxy resins, naphthol aralkyl type epoxy resins, polyvinylphenol type epoxy resins, diphenylmethane type epoxy resins, diphenylsulfone type epoxy resins, triphenolalkane type epoxy resins, cresol-naphthol co-condensation type epoxy resins, bisphenylethylene type epoxy resins, fluorene type epoxy resins, stilbene type epoxy resins, spirocoumarone type epoxy resins, norbornene type epoxy resins, terpene type epoxy resins, phenolcyclohexane type epoxy resins, halogenated epoxy resins, imide group-containing epoxy resins, maleimide group-containing epoxy resins, allyl group-modified epoxy resins, and silicone-modified epoxy resins. Examples of the phenolic resin include polyvinylphenol type, phenol novolak type, naphthol type, terpene type, phenol dicyclopentadiene type, phenol aralkyl type, naphthol aralkyl type, triphenol alkane type, dicyclopentadiene type, cresol-naphthol co-condensation type, and xylene-naphthol co-condensation type.Examples of silicone resins include epoxy-modified silicone resins obtained by reacting an epoxy resin with a silanol group or a silicon-bonded alkoxy group in the silicone resin. Examples of the curing mechanism of such curable resins include heat curing, high-energy ray curing such as ultraviolet light or radiation, moisture curing, condensation reaction curing, and addition reaction curing. The state of such curable resins at 25°C is not limited, and they may be either liquid or solid that softens when heated.

[0107] The organic resin containing the silicone elastomer particles of the present invention can contain other optional components such as curing agents, curing accelerators, fillers, photosensitizers, higher fatty acid metal salts, ester waxes, plasticizers, etc. Examples of the curing agents include organic acids such as carboxylic acids and sulfonic acids and their anhydrides; organic hydroxy compounds; organosilicon compounds having silanol groups, alkoxy groups, or halogeno groups; primary or secondary amino compounds, and these can also be used in combination of two or more. Examples of the curing accelerator include tertiary amine compounds, organometallic compounds such as aluminum and zirconium; organophosphorus compounds such as phosphines; heterocyclic amine compounds, boron complex compounds, organic ammonium salts, organic sulfonium salts, organic peroxides, and hydrosilylation catalysts. Examples of fillers include fibrous fillers such as glass fiber, asbestos, alumina fiber, ceramic fiber containing alumina and silica, boron fiber, zirconia fiber, silicon carbide fiber, metal fiber, polyester fiber, aramid fiber, nylon fiber, phenolic fiber, and natural animal and plant fibers; and particulate fillers such as fused silica, precipitated silica, fumed silica, calcined silica, zinc oxide, calcined clay, carbon black, glass beads, alumina, talc, calcium carbonate, clay, aluminum hydroxide, barium sulfate, titanium dioxide, aluminum nitride, silicon carbide, magnesium oxide, beryllium oxide, kaolin, mica, and zirconia, and these may be used in combination. In the case of epoxy resins, it is particularly preferable to include an amine-based curing agent.

[0108] The silicone elastomer particles of the present invention may be incorporated as an additive into thermoplastic resins other than those mentioned above, and may be used as a physical property modifier (e.g., surface lubricant or stress relief agent) or an optical property modifier (e.g., light scattering agent). The type of thermoplastic resin is not particularly limited, and may be at least one polymer selected from the group consisting of polycarbonate resins, polyester resins, polyether resins, polylactic acid resins, polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymers, polystyrene resins, styrene copolymers, fluorine-containing polymers such as tetrafluoroethylene, polyvinyl ethers, and cellulose polymers, or a composite resin composed of a combination thereof. The silicone resin-coated silicone elastomer particles of the present invention can be uniformly dispersed in these thermoplastic resins (including masterbatches) using a mixing device such as a twin-screw or single-screw extruder or kneader / mixer, and may be molded into a desired shape, such as a film, for use.

[0109] The amount of silicone elastomer particles of the present invention added can be selected appropriately depending on the physical properties required of the organic resin, but is generally in the range of 0.1 to 30 parts by mass, and may be in the range of 0.5 to 10 parts by mass, per 100 parts by mass of organic resin. If the amount of the particles added is less than the lower limit, performance such as stress relaxation properties for the resin may be insufficient, and the flexibility and thermal shock resistance of the resulting cured organic resin, particularly the thermal shock resistance after moisture absorption, tend to be reduced. On the other hand, if the amount exceeds the upper limit, the organic resin or paint / coating agent may thicken after blending, reducing handling and workability, and the mechanical properties of the resulting cured organic resin tend to be reduced.

[0110] Furthermore, since the silicone elastomer particles of the present invention have excellent stress relaxation properties when blended with organic resins, they may be blended with epoxy resins, etc. for printed wiring boards to form prepregs. Furthermore, copper foil with a filler particle-containing resin layer for printed wiring boards may be formed by providing a resin layer containing the silicone elastomer particles of the present invention on one side of the copper foil, and used in copper-clad laminates (CCLs).

[0111] [Paints and Coating Agents] Paints and coating agents containing the silicone elastomer particles of the present invention can be exemplified by room temperature curing types, room temperature drying types, and heat curing types, and depending on their properties, they can be water-based, oil-based, and powder-based. Furthermore, depending on the vehicle resin, examples include polyurethane resin paints, butyral resin paints, long oil phthalic acid resin paints, alkyd resin paints, amino alkyd resin paints consisting of amino resins and alkyd resins, epoxy resin paints, acrylic resin paints, phenolic resin paints, silicone-modified epoxy resin paints, silicone-modified polyester resin paints, and silicone resin paints.

[0112] The amount of silicone elastomer particles of the present invention added can be selected appropriately depending on the physical properties required of the paint or coating agent, but in order to impart a uniform and soft matte finish to the resulting paint film, it is preferably in the range of 0.1 to 150 parts by mass, more preferably 0.1 to 100 parts by mass, and particularly preferably 0.1 to 50 parts by mass, or 0.1 to 20 parts by mass, per 100 parts by mass of the solids content of the paint. If the amount of the particles added is less than the above-mentioned lower limit, the matte finish, adhesion, stress relaxation properties, and other performance characteristics of the paint film may be insufficient, while if the amount exceeds the above-mentioned upper limit, the organic resin or paint or coating agent after blending may thicken, reducing handling and workability.

[0113] Paints and coating agents containing the silicone elastomer particles of the present invention may contain alcohols such as methanol and ethanol; ketones such as methyl ethyl ketone and methyl isobutyl ketone; esters such as ethyl acetate, butyl acetate and cellosolve acetate; amides such as N,N-dimethylformamide; olefins such as hexane, heptane and octane; organic solvents such as aromatic hydrocarbons such as toluene and xylene; known inorganic fillers such as reinforcing silica, organic fillers, curing accelerators, silane coupling agents, pigments such as carbon black, dyes, antioxidants, thickeners made of polymeric compounds, flame retardants, and weather resistance imparting agents.

[0114] [As an eco-friendly material] As mentioned above, the silicone elastomer particles of the present invention are different from conventional non-biodegradable thermoplastic resin particles and silicone particle materials, and are expected to have biodegradable properties in that, in a biodegradable environment, the cross-linked structure formed between silicon atoms in the silicone elastomer particles at least partially cleaves, and the primary particles of the silicone elastomer particles are disintegrated, accompanied by the generation of non-cross-linked polyorganosiloxanes.Therefore, they can be used as "eco-friendly" cosmetic raw materials and industrial raw materials that have low environmental load and environmental risk and comply with regulations such as microplastics, and can be expected to be able to appeal to users and general consumers who are concerned about the impact on the global environment as "eco-friendly" materials with biodegradability.

[0115] The reactive group-containing polycaprolactone compound of the present invention (specifically, a compound selected from the above-mentioned (meth)acrylic-modified polycaprolactone compound and alkenyl-modified polycaprolactone compound), silicone elastomer particles made therefrom, and a method for producing the same will be described in detail with reference to examples and comparative examples. However, the present invention is not limited to these examples. The viscosity values ​​in the examples are values ​​at 25°C. The properties of each silicone particle were measured as follows. Unless otherwise specified in the examples, silicone particles is a general term for particles made of a cured silicone (cured silicone particles) and does not include emulsions.

[0116] [Average Primary Particle Diameter of Emulsion Particles] The emulsion before the addition of the radical polymerization initiator and before the addition of the hydrosilylation catalyst was measured using a laser diffraction particle size distribution analyzer (LS-230 manufactured by Beckman Coulter), and the median diameter (particle size corresponding to 50% of the cumulative distribution, 50% particle size) was taken as the average particle size.

[0117] [Average secondary particle diameter of silicone particles (powder)] Using ethanol as a dispersion medium, the particle diameter of cured silicone particles was measured using a laser diffraction particle size distribution analyzer (Malvern Panalytical's Mastersizer 3000), and the median diameter (particle diameter corresponding to 50% of the cumulative distribution, D90, μm) and arithmetic dispersity (indicating the degree of dispersion of the particle size distribution, SD, μm2) of the cured silicone particles in ethanol were obtained. To prepare a measurement sample, cured silicone particles (1 g) and ethanol (100 mL) were dispersed in a 300 mL cup using a stirring blade and an ultrasonic vibrator.

[0118] The component (A) used in the examples and comparative examples is as follows. Note that "Me" means a methyl group. (a2-1) Structural formula: Me ３ SiO-(Me ２ SiO) ３４ -(Me(H)SiO) １６ (a1-1) Dimethylsiloxane-methylhydrogensiloxane copolymer having both ends blocked with trimethylsiloxy groups, represented by —SiMe3, and having the following structural formula: (wherein m=4, n=267) is a methacrylic-modified silicone polymer (viscosity at 25°C: 1524 mPas), and an example of its synthesis is as follows.

[0119] Synthesis Example: A four-neck separable flask was charged with 92.07 parts by weight of dodecamethylcyclosiloxane, 0.01 parts by weight of MEHQ (hydroquinone monomethyl ether, polymerization inhibitor), and 5.88 parts by weight of 3-methacryloxypropylmethyldimethoxysilane. The mixture was heated while stirring at 200 rpm and aerating with N2. When the mixture reached 50°C, 0.05 parts by weight of trifluoromethanesulfonic acid and 1.09 parts by weight of water were added. After reacting at 55°C for 2 hours, the mixture was heated to 70°C. The pressure was further reduced to 100 mmHg, and the by-product methanol was removed for approximately 1 hour. 0.90 parts by weight of hexamethyldisiloxane was then added, and the reaction continued for 3 hours. After the reaction, ammonia gas was bubbled through the mixture to neutralize the trifluoromethanesulfonic acid, and the resulting salt was removed by diatomaceous earth filtration. The filtrate was then vacuum treated at 150°C for 3 hours to remove volatile components. C, Si-NMR analysis revealed that (a1-1) a methacrylic-modified silicone polymer was obtained with 267 dimethylsiloxane units, 4 methacrylic group-introduced siloxane units, and a viscosity of 1524 mPas.

[0120] [Examples 1 to 6: Synthesis of (meth)acrylic-modified polycaprolactone compounds Nos. 1 to 3 and alkenyl-modified polycaprolactone compounds Nos. 4 to 6] Hereinafter, examples of synthesis of (meth)acrylic-modified polycaprolactone compounds according to the present invention by reacting a polycaprolactone compound having a polyol terminal structure with a specific (meth)acryloyl chloride compound will be described. These components are the components used as silicone elastomer raw materials in Examples 5 and onward described below.

[0121] Example 1: (Meth)acrylic-Modified Polycaprolactone Compound No. 1. A four-neck separable flask was charged with 18.81 parts by weight of Placel 205 (manufactured by Daicel Corporation, diol-type polycaprolactone, molecular weight: 530), 18.81 parts by weight of chloroform, 8.77 parts by weight of triethylamine, and 0.03 parts by weight of MEHQ (hydroquinone monomethyl ether, polymerization inhibitor). While stirring at 200 rpm and aerating with 2% O2-containing N2, 6.55 parts by weight of acryloyl chloride was added dropwise. The mixture was cooled in a water bath to prevent heat generation from exceeding 30°C. After the addition was complete, the stirring time was extended by 1 hour. The liquid temperature was then raised to 50°C and aged for approximately 2 hours. Next, 28.21 parts by weight of water-1 was added and the mixture was stirred thoroughly. The mixture was then transferred to a separatory funnel, and the lower phase containing the modified polycaprolactone was removed. An additional 18.81 parts by weight of water-2 was added to homogenize the mixture. The mixture was then transferred to a separatory funnel and left overnight to allow for further separation. After overnight, the solution was removed and transferred to another four-neck flask. While bubbling with 2% O2-containing N2, the chloroform was removed under reduced pressure, yielding a transparent orange polymer. H-NMR analysis of the polymer revealed peaks attributable to acrylic groups, confirming that it was polycaprolactone ((meth)acrylic-modified polycaprolactone compound No. 1) with the following structure: (In the formula, m+n=3.7)

[0122] Example 2 (Meth)acrylic-Modified Polycaprolactone Compound No. 2 The same procedure as in Example 1 was carried out, except that the ingredients were changed to 17.92 parts by weight of Placel 305 (trade name, manufactured by Daicel Corporation, triol-type polycaprolactone, molecular weight: 550), 17.92 parts by weight of chloroform, 10.27 parts by weight of triethylamine, 0.05 parts by weight of MEHQ, 9.02 parts by weight of acryloyl chloride, 26.89 parts by weight of Water-1, and 17.92 parts by weight of Water-2, to obtain polycaprolactone ((meth)acrylic-modified polycaprolactone compound No. 2) whose terminals were modified with acrylic groups and had the following structure. (In the formula, x+y+z=3.7)

[0123] Example 3 (Meth)acrylic-Modified Polycaprolactone Compound No. 3 The same procedure as in Example 1 was carried out, except that the ingredients were changed to 18.70 parts by weight of Placel 410 (trade name, manufactured by Daicel Corporation, tetraol-type polycaprolactone, molecular weight: 1000), 18.70 parts by weight of chloroform, 7.86 parts by weight of triethylamine, 0.02 parts by weight of MEHQ, 6.91 parts by weight of acryloyl chloride, 28.69 parts by weight of Water-1, and 19.12 parts by weight of Water-2, to obtain polycaprolactone ((meth)acrylic-modified polycaprolactone compound No. 3) whose terminals were modified with acrylic groups and had the following structure. (In the formula, w+x+y+z=7.6)

[0124] Example 4: Alkenyl-modified polycaprolactone compound No. 4. A four-neck separable flask was charged with 27.36 parts by weight of Placel 305 (manufactured by Daicel Corporation, triol-type polycaprolactone, molecular weight: 550), 27.36 parts by weight of chloroform, and 14.41 parts by weight of potassium carbonate. While stirring at 200 rpm and bubbling with N2, 30.86 parts by weight of undecenoyl chloride was added dropwise. The mixture was cooled in a water bath to prevent heat generation from exceeding 30°C. After the addition was completed, the mixture was stirred for 24 hours, and the by-product was filtered. The organic solution was transferred to another four-neck flask, and while bubbling with N2, the chloroform and excess undecylenic acid were removed under reduced pressure, yielding a transparent polymer. H-NMR analysis of the polymer showed a peak derived from undecyl groups, and polycaprolactone (alkenyl-modified polycaprolactone compound No. 4) having the following structure and modified at the terminal with undecyl groups was obtained. (In the formula, x+y+z=3.7)

[0125] Example 5: Alkenyl-modified polycaprolactone compound No. 5. A four-neck separable flask was charged with 57.62 parts by weight of Placel 210 (manufactured by Daicel Corporation, diol-type polycaprolactone, molecular weight: 1000) and 42.35 parts by weight of vinylsilazane. The mixture was heated to 50°C and, while stirring and aerating with N2, 0.02 parts by weight of trifluoromethanesulfonic acid was added dropwise. The reaction was allowed to proceed at 50°C for 4 hours. 3.00 parts by weight of Kyoward 500 (manufactured by Kyowa Chemical Industry Co., Ltd.: synthetic hydrotalcite) was added and stirred for 1 hour. After filtration, minor components were removed by bubbling with N2, yielding a transparent polymer. H-NMR and Si-NMR analysis of the polymer revealed peaks attributable to vinylsiloxy groups, yielding a polycaprolactone (alkenyl-modified polycaprolactone compound No. 5) with the following structure, terminally modified with vinylsiloxy groups. (In the formula, m+n=7.9)

[0126] Example 6: Alkenyl-modified polycaprolactone compound No. 6. A four-neck separable flask was charged with 35.12 parts by weight of Pluronic L-31 (manufactured by ADEKA Corporation, diol-type polyoxyethylene-polyoxypropylene copolymer, molecular weight: approximately 1100), 49.70 parts by weight of chloroform, and 0.22 parts by weight of triazabicyclodecene. 14.58 parts by weight of ε-caprolactone was added dropwise while bubbling with N2. The mixture was stirred at room temperature for 4 hours. After the reaction, 0.38 parts by weight of benzoic acid was added. After leaving the mixture overnight, the chloroform was removed under reduced pressure while bubbling with N2, yielding a transparent polymer. 83.21 parts by weight of the resulting polymer and 16.79 parts by weight of vinylsilazane were charged. The mixture was heated to 50°C while bubbling with N2, and 0.02 parts by weight of trifluoromethanesulfonic acid was added and allowed to react for 4 hours. After filtration, minor components were removed by bubbling with N2, yielding a transparent polymer. H-NMR and Si-NMR analyses of the polymer revealed peaks attributable to vinylsiloxy groups, indicating that polycaprolactone (alkenyl-modified polycaprolactone compound No. 6) with terminal vinylsiloxy groups had been obtained, with the following structure: (In the formula, m+n=4.0, a+b=18)

[0127] [Examples 7 to 12, Comparative Example 1: Production of Silicone Elastomer Particles] Examples of production of silicone elastomer particles obtained using the above-mentioned (meth)acrylic-modified polycaprolactone compound as a raw material are shown below in Examples 7 to 12. Note that Comparative Example 1 is a non-silicone polymer particle obtained using only the (meth)acrylic-modified polycaprolactone compound as a raw material.

[0128] Example 7: Silicone Elastomer Particles No. 1 (Hydrosilylation Reaction Type) An organohydrogenpolysiloxane (a2-1) and an alkenyl-modified polycaprolactone compound (b4) (No. 4) were mixed uniformly at room temperature in a mass ratio of 37:63. This composition was then dispersed in a 25°C aqueous solution consisting of 0.5 parts by mass of polyoxyethylene alkyl (C12-14) ether and 30 parts by mass of pure water, and the resulting mixture was further emulsified uniformly using a colloid mill. The resulting mixture was then diluted with 526 parts by mass of pure water to prepare an emulsion. An isopropyl alcohol solution of chloroplatinic acid (in an amount such that the platinum metal content in the composition was 10 ppm by mass) was then added to the emulsion as an aqueous dispersion of polyoxyethylene alkyl (C12-14) ether and pure water, and the mixture was stirred. The resulting emulsion was then allowed to stand at 50°C for 4 hours to prepare a uniform aqueous suspension of elastomer particles. Next, this aqueous suspension was filtered, and the residue was dried in an oven at 50°C for 5 hours to obtain silicone elastomer particles No. 1. The average primary and secondary particle sizes of the obtained silicone elastomer particles were 4.03 μm and 15.3 μm, respectively. An electron microscope photograph of the particles is shown in Figure 1.

[0129] Example 8: Silicone Elastomer Particles No. 2 (Radical Polymerization Type)] A methacrylic-modified silicone polymer (component (a1-1)) and a (meth)acrylic-modified polycaprolactone compound No. 1 (b1) were mixed uniformly at room temperature in a mass ratio of 30:70, and then olive oil (manufactured by Summit Oil Mills) was added in an amount equivalent to 20% of the total composition. This composition was then dispersed in a 25°C aqueous solution consisting of 0.27 parts by mass of Gohsenol EG-05C, 0.53 parts by mass of Gohsenol EG-18P, and 46 parts by mass of pure water. The resulting mixture was then uniformly emulsified using a colloid mill and diluted with 300 parts by mass of pure water to prepare an emulsion. The mixture was heated in a 1-L flask until the temperature reached 60°C, at which point an aqueous solution of 0.5 g of potassium persulfate (manufactured by Sigma-Aldrich) dissolved in 9.5 g of water was added dropwise over 1 minute. This emulsion was stirred at 100 rpm at 60°C for 3 hours to allow radical polymerization, producing a uniform aqueous suspension of silicone rubber particles. This aqueous suspension was then filtered and washed with 200 ml of ethanol and 100 ml of acetone. The residue was dried in an oven at 70°C for 3 hours to obtain silicone elastomer particles No. 2. The average primary and secondary particle sizes of the resulting silicone elastomer particles were 3.41 μm and 31.1 μm, respectively.

[0130] Example 9: Silicone elastomer particles No. 3 (radical polymerization type)] A methacrylic-modified silicone polymer (a1-1) and (b2) (meth)acrylic-modified polycaprolactone compound No. 2 were uniformly mixed at room temperature in a mass ratio of 30:70. Other than that, silicone elastomer particles No. 3 were obtained in the same manner as in Example 8. The average primary and secondary particle diameters of the obtained silicone elastomer particles were 3.43 μm and 31.1 μm, respectively. An electron microscope photograph thereof is shown in FIG. 2.

[0131] Example 10: Silicone elastomer particles No. 4 (radical polymerization type)] A methacrylic-modified silicone polymer (a2-1) and (b3) (meth)acrylic-modified polycaprolactone compound No. 3 were uniformly mixed at room temperature in a mass ratio of 30:70. Other than that, silicone elastomer particles were obtained in the same manner as in Example 8. The average primary and secondary particle diameters of the obtained silicone elastomer particles were 4.42 μm and 336 μm, respectively.

[0132] [Example 11: Silicone elastomer particles No. 5 (hydrosilylation reaction type)] Component (a1-1) organohydrogenpolysiloxane and (b5) alkenyl-modified polycaprolactone compound No. 5 were uniformly mixed at room temperature in a mass ratio of 18.7:81.3. Otherwise, silicone elastomer particles No. 5 were obtained in the same manner as in Example 7. The average primary and secondary particle diameters of the obtained silicone elastomer particles were 3.73 μm and 18.5 μm, respectively.

[0133] Example 12: Silicone elastomer particles No. 6 (hydrosilylation reaction type)] Component (a1-1) organohydrogenpolysiloxane and (b6) alkenyl-modified polycaprolactone compound No. 6 were uniformly mixed at room temperature in a mass ratio of 15:85. Other than that, silicone elastomer particles No. 6 were obtained in the same manner as in Example 7. The average primary and secondary particle sizes of the obtained silicone elastomer particles were 0.95 μm and 30.2 μm, respectively.

[0134] Comparative Example 1 (Radical Polymerization Type) Non-silicone polymer particles were obtained in the same manner as in Example 6, except that no polyorganosiloxane component was used and only 100 parts by mass of (b1) (meth)acrylic-modified polycaprolactone compound No. 1 was used. The average primary and secondary particle diameters of the obtained particles were 2.91 μm and 70.0 μm, respectively.

[0135] The average primary particle size and average secondary particle size of each of the particles obtained in Examples 7 to 12 and Comparative Example 1 are summarized in Table 1 below. As shown in Figures 1 and 2, when the silicone elastomer particles obtained in Examples 7 and 9 were observed with a digital microscope, they were found to be almost free of aggregation, confirming excellent dispersibility.

[0136] [Cosmetic Formulation Examples] Below are examples of cosmetic formulations of the present invention that can incorporate silicone elastomer particles, which are one aspect of the present invention, although the present invention is not limited to these.

[0137] [Examples 9 and 10, Comparative Example 2] Panelists compared and evaluated the feel of use of loose powders using silicone elastomer particles with the compositions shown in Table 3 below. (Tactile evaluation) Eighteen panelists applied samples to the inside of their forearms and evaluated the smoothness according to the criteria in Table 2 below.

[0138] (Preparation Method) 1. Mix Phase A. 2. Mix Phase B. 3. Stir Phase A and Phase B until uniform.

[0139] As shown in Table 3, the loose powder using the silicone elastomer particles of the present invention (Example 1, hydrosilylation reaction type) was evaluated to have good slip properties, unlike the loose powder using other particles (Comparative Example 1).

[0140] [Examples 17, 18, and 19, and Comparative Examples 3, 4, and 5] Panelists compared and evaluated the feel of use of water-in-oil sunscreen agents using silicone elastomer particles with the compositions shown in Table 5. (Feeling Evaluation) Eighteen panelists applied samples to the inside of their forearms and evaluated the ease of spread, smoothness, moist feeling, and absence of squeaky feeling according to the criteria in Table 4 below. [SPF Value and PA Value] The evaluation target (sunscreen cosmetic) was uniformly applied to HELIOPLATE HD6 (manufactured by HelioScreenLab) so as to be 2 mg / cm2, and the SPF value and PA value were measured using an SPF measuring device UV-1000S (manufactured by Labsphere Co., Ltd.) The values ​​shown in Tables 1 to 3 are the average values ​​obtained by measuring 10 locations on each of three test samples, excluding the maximum and minimum values.

[0141] (Preparation method) Mix phase A. Mix phase B. While stirring phase A, slowly add phase B. Add phase C to the above 4 and stir until uniform.

[0142] As shown in Table 5, the water-in-oil sunscreen using silicone elastomer particles No. 1 (Example 5) of the present invention was evaluated as having good spreadability, a smooth, moist feel, and less squeaky feel, unlike sunscreens using Comparative Example 5, which does not contain elastomer particles, or other particles (Comparative Example 4).Furthermore, it was evaluated as providing a superior feel to the touch compared to the existing product (Comparative Example 5).In addition, Example 11, which contains the silicone elastomer particles of the present invention, was able to significantly improve the SPF value and PA value compared to sunscreens containing other particles, without compromising the feel when used.

[0143] Examples 20 and 21, Comparative Examples 6, 7 and 8 The feel of use of water-in-oil foundations using silicone elastomer particles with the compositions shown in Table 6 was compared and evaluated by a panel. (Preparation method) Mix phase A. Mix phase B. Mix phase A and phase B. While stirring phase AB, slowly add phase C. Add phase D to the above 4 and stir until uniform. (Texture evaluation) The spreadability and moist feeling were evaluated when the samples were applied to the inside of the forearms of 18 panelists.

[0144] [Examples 22 and 23, Comparative Example 9] The performance of anti-wrinkle creams using silicone elastomer particles with the compositions shown in the table below was compared and evaluated. (Preparation method) Mix phase A. Mix phase B. Mix phase B and phase C. While stirring phase A, slowly add phase BC. (Tactile evaluation) The sample was evenly applied to a glass slide to a thickness of 75 μm, and the appearance of letters printed on paper placed below the glass slide was visually observed.

[0145] Enzymatic Degradation Test of Silicone Elastomer Particles [Examples 7, 8, and 12 (Silicone Elastomer Particles Nos. 1, 2, and 6) and Existing Silicone Elastomer Products] 0.1 g of each of the prepared silicone elastomer particles and an existing silicone elastomer product (manufactured by Dow-Toray Industries, Inc., product name: EP-9610 Cosmetic Powder; silicone elastomer particles obtained by hydrosilylation of alkenyl-modified polysiloxane and organohydrogenpolysiloxane) was weighed and placed in an Eppendorf tube. Type XIII lipase derived from Pseudomonas bacteria was mixed with 0.1 M phosphate-buffered saline (pH 7.4) to prepare an 8 U / mL enzyme solution. 1 mL of the resulting enzyme solution was added to each tube to prepare test specimens. The specimens were placed in a 37°C oven and tested for up to 96 hours, with the enzyme replaced every 24 hours. After a predetermined time, each sample was removed, washed with water, dried overnight, and then completely dried in a vacuum oven. The weight of the sample after complete drying was measured, and the weight loss rate was defined as the decomposition rate. The enzymatic decomposition test (test time - decomposition rate %) is shown in Figure 3.

[0146] Silicone elastomer particles Nos. 1 and 6 of Examples 7 and 12 have a structure crosslinked by polycaprolactone having alkenyl groups and organohydrogenpolysiloxane having silicon-bonded hydrogen atoms in the presence of a hydrosilylation catalyst, while silicone elastomer particle No. 2 of Example 8 has a structure crosslinked by (meth)acrylic-modified siloxane and polycaprolactone having (meth)acrylic-modified groups in the presence of a radical polymerization catalyst.

[0147] The silicone elastomer particles according to these Examples all show a weight loss over time in the presence of enzymes, and are therefore presumed to be degradable. In particular, the silicone elastomer particles according to Examples 8 and 12 both show a high decomposition rate of over 9% after 96 hours, and the silicone elastomer particles according to the Examples of the present application are highly expected to be biodegradable.

[0148] On the other hand, the elastomer particles obtained by hydrosilylation of alkenyl-modified siloxane and organohydrogenpolysiloxane do not have enzyme-degradable groups like polyester, and no weight loss was observed even in the presence of enzymes, so it is presumed that they are not biodegradable. In particular, the decomposition rates of the silicone elastomer particles according to the examples and existing silicone elastomer products after 96 hours show a clear and significant difference, which strongly suggests that the silicone elastomer particles according to the present invention have the advantages of performance and feel equal to or better than existing products, as well as achieving high biodegradability, which has been difficult to achieve with existing silicone elastomer products.

Claims

1. The molecule contains the following structural formula (1): 【Chemistry 1】 （１） {wherein n is a number ranging from 1 to 5, and Ra is -R １ -CR ２ =CH ２ (R １ is a carbonyl group or a divalent linking group containing one carbonyl group, and R ２ a (meth)acrylic terminal group and an alkenyl terminal group}, each of which is a hydrogen atom or a methyl group;

2. The modified polycaprolactone copolymer has 2 to 4 modified polycaprolactone structures represented by the following structural formula (1) in the molecule, and the caprolactone unit {—C(═O)—C ５ H １０ 2. The reactive group-containing polycaprolactone compound according to claim 1, wherein the reactive group-containing polycaprolactone compound has 2 to 20 —O—}.

3. In the functional group Ra in the following structural formula (1), R １ 2. The reactive group-containing polycaprolactone compound according to claim 1, wherein is a carbonyl group or a divalent linking group containing one carbonyl group and selected from organic groups having 1 to 20 carbon atoms and silicon-containing organic groups.

4. The reactive group-containing polycaprolactone compound according to claim 1, represented by one or more structural formulas selected from the following structural formulas (1-1) to (1-5): Structural formula (1-1): 【Chemistry 2】 （１－１） Structural formula (1-2): 【Transformation 3】 （１－２） Structural formula (1-3): 【Chemistry 4】 （１－３） Structural formula (1-4): 【Transformation 5】 （１－４） Structural formula (1-5): 【Transformation 6】 （１－５） (wherein Ra is the same group as defined above; m and n each independently represent a number in the range of 1 to 5, and m+n represents a number in the range of 2 to 20; w, x, y, and z each independently represent a number in the range of 1 to 5, and x+y+z represents a number in the range of 3 to 20, and w+x+y+z represents a number in the range of 4 to 20)

5. The reactive group-containing polycaprolactone compound according to any one of claims 1 to 4, which is a raw material for synthesizing silicone elastomer particles.

6. The molecule contains the following structural formula (1'): 【Transformation 7】 （１´） (wherein n is a number ranging from 1 to 5.) a polycaprolactone compound having two or more polycaprolactone structures each having a polyol terminal structure represented by the formula: Cl—C(═O)—R １ -CR ２ =CH ２ (R １ is a chemical bond between CH and C(=O) or a divalent organic group having 1 to 20 carbon atoms, and R ２ a (meth)acryloyl chloride compound represented by the formula (I) above, wherein R is a hydrogen atom or a methyl group, and an alkenoyl chloride are reacted in the presence of a basic catalyst, and tetramethyldivinyldisilazane is reacted in the presence of an acidic catalyst.

7. Silicone elastomer particles having a structure in which at least two silicon atoms within the silicone elastomer particles are crosslinked by one or more reactions selected from the group consisting of a radical polymerization reaction of the reactive group-containing polycaprolactone compound according to any one of claims 1 to 4 and a hydrosilylation reaction of silicon-bonded hydrogen atoms.

8. Within the silicone elastomer particles, -(R １ ２ SiO) ｎ - (In the formula, R １ is an unsubstituted or halogen-substituted alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 22 carbon atoms, or a hydroxyl group, and n is a number ranging from 1 to 1000. The silicone elastomer particles according to claim 7, further comprising a polyorganosiloxane structure represented by the formula:

9. (A) at least one reactive organopolysiloxane selected from the following components (a1) and (a2): (a1) an organopolysiloxane having at least three (meth)acryloxy group-containing organic groups in the molecule, each of which is at least one type selected from methacryloxy group-containing organic groups and acryloxy group-containing organic groups; and (a2) Organopolysiloxane having at least three silicon-bonded hydrogen atoms in the molecule (B) The reactive group-containing polycaprolactone compound according to any one of claims 1 to 4. (C) One or more curing agents selected from radical polymerization initiators and hydrosilylation reaction catalysts The silicone elastomer particles according to claim 7, which are silicone elastomer particles obtained by crosslinking in water crosslinkable reactive silicone emulsion particles obtained by emulsifying in water a crosslinkable reactive silicone composition which contains at least

10. 8. The silicone elastomer particles according to claim 7, wherein the average primary particle size measured by a laser diffraction scattering method is 0.5 to 20 μm.

11. 8. The silicone elastomer particles according to claim 7, wherein the cross-linkable silicone composition used to form the silicone elastomer particles has a JIS-A hardness of 10 to 80 as measured after curing the composition into a sheet.

12. 8. The silicone elastomer particles according to claim 7, having a structure in which a part or all of the surface thereof is covered with one or more materials selected from organopolysiloxane resin, silica, and other silicone elastomer particles.

13. The silicone elastomer particles according to claim 7 , wherein the silicone elastomer particles have a mesoporous structure.

14. The silicone elastomer particles according to claim 7, wherein the silicone elastomer particles contain an oil that is liquid at 40°C.

15. The silicone elastomer particles according to claim 7, characterized in that they are biodegradable.

16. 8. The silicone elastomer particles according to claim 7, wherein the divalent organic group having a partial structure formed by radical polymerization or hydrosilylation reaction of the reactive group-containing polycaprolactone compound within the silicone elastomer particles is active in biodegradable reactions, and in a biodegradable environment, the crosslinked structure formed between silicon atoms within the silicone elastomer particles is at least partially cleaved, and the primary particles of the silicone elastomer particles are disintegrated while generating polyorganosiloxane with an uncrosslinked structure.

17. A cosmetic raw material containing the silicone elastomer particles according to any one of claims 7 to 16.

18. A cosmetic composition containing the silicone elastomer particles according to claim 7.

19. An organic resin additive containing the silicone elastomer particles according to claim 7.

20. An organic resin containing the silicone elastomer particles according to claim 7.

21. The method for producing silicone elastomer particles according to claim 7, comprising the following steps (I) and (II): Step (I): (A) at least one reactive organopolysiloxane selected from the following components (a1) and (a2): (a1) an organopolysiloxane having at least three (meth)acryloxy group-containing organic groups in the molecule, each of which is at least one type selected from methacryloxy group-containing organic groups and acryloxy group-containing organic groups; and (a2) Organopolysiloxane having at least three silicon-bonded hydrogen atoms in the molecule (B) The reactive group-containing polycaprolactone compound according to any one of claims 1 to 4. (C) One or more curing agents selected from radical polymerization initiators and hydrosilylation reaction catalysts in water to form cross-linked reactive silicone emulsion particles; Step (II): (C) a step of curing the crosslinkable reactive silicone emulsion particles obtained in step (I) in the presence of a curing agent to obtain silicone elastomer particles.

22. In step (I), at least a part of component (A) is 22. The method for producing silicone elastomer particles according to claim 21, wherein (a1) is an organopolysiloxane having, in the molecule, at least three (meth)acryloxy group-containing organic groups, each of which is at least one type selected from methacryloxy group-containing organic groups and acryloxy group-containing organic groups.

Images