JP2000204258A - Granular silicone cured product and preparation thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a granular silicone cured product which has a peculiar viscoelasticity and gives a good feel, and a preparation process thereof. SOLUTION: The granular silicone cured product, which has an average particle size of from 0.1 to 500 μm, is prepared by curing (A) 100 pts.wt. polydiorganosiloxane having at least two silicon atom-bound alkenyl groups within a molecule, (B) from 1 to 50 pts.wt. polyorganosiloxane resin of the formula: (R3SiO1/2)x(SiO4/2)1.0 (wherein multiple R are each an identical or different monovalent hydrocarbon group; and x is from 0.6 to 4.0) and (C) a polyorganosiloxane having at least two silicon atom-bound hydrogen atom within a molecule at an amount which cures component (A) or components (A) and (B) through crosslinking} using a catalytic amount of (D) a platinum catalyst. In the preparation process of the granular silicone cured product, 100 pts.wt. component (A), from 1 to 50 pts.wt. component (B) and component (C) at an amount which cures component (A) or components (A) and (B) through crosslinking} are dispersed in water by an emulsifier and cured using a catalytic amount of component (D).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cured particulate silicone material and a method for producing the same, and more particularly, to a cured particulate silicone material having a special viscoelasticity and a good tactile sensation.
It relates to the manufacturing method.

[0002]

2. Description of the Related Art Curing comprising a polyorganosiloxane having at least two silicon-bonded alkenyl groups in one molecule, a polyorganosiloxane having at least two silicon-bonded hydrogen atoms in one molecule, and a platinum-based catalyst By curing the water-soluble silicone composition in a dispersed state in water with an emulsifier, the average particle size is 0.1 to 500.
It is known that a particulate silicone cured product having a particle size of μm can be prepared. As a polyorganosiloxane having at least two silicon-bonded alkenyl groups in one molecule, CH ₂ ＣＨCH (CH ₃ ) ₂ SiO _1/2 units And (CH ₃ ) ₃ Si
It is also known that a polyorganosiloxane resin consisting of O _1/2 units and SiO _4/2 units can be blended (Japanese Patent Laid-Open No. Sho 62).
-243621, JP-A-63-17959, JP-A-63-77942, and
198324).

However, although these publications describe that the above-mentioned polyorganosiloxane resins can be blended, the blending amount with respect to the polydiorganosiloxane having at least two silicon-bonded alkenyl groups in one molecule is described. Is not described, and is merely an example as a polyorganosiloxane having an alkenyl group.

[0004]

SUMMARY OF THE INVENTION The present inventors have conventionally
A polyorganosiloxane resin as described above, which has been known as a component of a curable silicone composition for forming a granular silicone cured product, comprises at least two silicon atom-bonded alkenyl groups in one molecule as a main component. When a granular silicone cured product was formed by adding a specific amount to the polydiorganosiloxane having, it was found that a granular silicone cured product having a special viscoelasticity and a good tactile sensation could be formed, and the present invention was reached. . That is, an object of the present invention is to provide a cured particulate silicone material having a special viscoelasticity and good tactile sensation, and a method for producing the same.

[0005]

The cured granular silicone of the present invention has an average particle size of 0.1 to 500 μm, and (A)
100 parts by weight of a polydiorganosiloxane having at least two silicon-bonded alkenyl groups in one molecule,
(B) Average unit formula: (R ₃ SiO _1/2 ) _x (SiO _4/2 ) _1.0 (wherein R is the same or different monovalent hydrocarbon group, and x is 0.6 to 4. 1 to 50 parts by weight of a polyorganosiloxane resin represented by the formula (A), and (C) a polyorganosiloxane having at least two silicon-bonded hydrogen atoms per molecule (A) component, or (C) A)
The amount by which the component and the component (B) can be cured by crosslinking is obtained by curing with a catalytic amount of the (D) platinum-based catalyst.

The process for producing a cured particulate silicone according to the present invention comprises: (A) a polydiorganosiloxane having at least two silicon-bonded alkenyl groups per molecule;
00 parts by weight, (B) average unit formula: (R ₃ SiO _1/2 ) _x (SiO _4/2 ) _1.0 (where R is the same or different monovalent hydrocarbon group, and x is 0. 1 to 50 parts by weight of a polyorganosiloxane resin represented by the following formula: (C) a polyorganosiloxane having at least two silicon-bonded hydrogen atoms per molecule {(A) Ingredient or (A)
An amount of the component (B) that can be cured by crosslinking with the component (B) is dispersed in water with an emulsifier, and cured with a catalytic amount of (D) a platinum-based catalyst.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the granular cured silicone of the present invention will be described in detail. The particulate silicone cured product of the present invention comprises the above component (A), component (B), and (C)
The component is cured by the component (D), and has an average particle size of 0.1 to 500 μm. this is,
This is because it is difficult to prepare a granular silicone cured product having an average particle size smaller than the lower limit of the above range, and on the other hand, the use of the particulate silicone cured product exceeding the upper limit of the above range is limited. The above component (A) is a main component for forming the cured particulate silicone of the present invention, and is a polydiorganosiloxane having at least two silicon-bonded alkenyl groups in one molecule. Examples of the alkenyl group include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, and a heptenyl group, and a vinyl group is particularly preferable. The bonding position of the alkenyl group may be, for example, a molecular chain terminal in component (A) and / or
Alternatively, a molecular side chain is exemplified. Examples of the group bonded to a silicon atom other than the alkenyl group in the component (A) include, for example, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and a heptyl group; Aryl groups such as phenyl, tolyl, xylyl and naphthyl; aralkyl such as benzyl and phenethyl; chloromethyl, 3-chloropropyl,
Examples include a halogenated alkyl group such as a 3,3-trifluoropropyl group, and a methyl group and a phenyl group are particularly preferable. Although the component (A) has a substantially linear molecular structure, a component having a branched structure in a part of the molecular chain may be used as long as the object of the present invention is not impaired. The viscosity of the component (A) at 25 ° C. is 10 to 10.
It is preferably in the range of 500,000 mPa · s, and particularly preferably in the range of 100 to 100,000 mPa · s. This is because if the viscosity at 25 ° C. of the component (A) is less than the lower limit of the above range, the mechanical strength of the obtained cured particulate silicone material is reduced. This is because it is difficult to obtain a cured particulate silicone having a particle size of 500 μm or less.

Examples of such a polydiorganosiloxane of the component (A) include a dimethylsiloxane / methylvinylsiloxane copolymer having a trimethylsiloxy group at both ends of a molecular chain, a polymethylvinylsiloxane having a trimethylsiloxy group at both ends of a molecular chain, Trimethylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane / methylphenylsiloxane copolymer at both ends of molecular chain, polydimethylsiloxane blocked at both ends of molecular chain, dimethylvinylsiloxy group-blocked polymethylvinylsiloxane, molecule Dimethylvinylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane copolymer at both ends of chain, dimethylsiloxane / methylvinylsiloxane / methylphenylsiloxane blocked at both ends of molecular chain San copolymers, and mixtures of two or more of these polydiorganosiloxanes are exemplified.

The component (B) is a component for imparting characteristic viscoelasticity to the granular silicone cured product of the present invention and improving the tactile sensation, and has an average unit formula: (R ₃ SiO _{1 / 2} ) A polyorganosiloxane resin represented by _x (SiO _4/2 ) _1.0 . R in the above formula is the same or different monovalent hydrocarbon group,
For example, methyl group, ethyl group, propyl group, butyl group,
Alkyl groups such as pentyl, hexyl and heptyl;
Alkenyl groups such as vinyl group, allyl group, butenyl group, pentenyl group, hexenyl group and heptenyl group; aryl groups such as phenyl group, tolyl group, xylyl group and naphthyl group; aralkyl groups such as benzyl group and phenethyl group; And a halogenated alkyl group such as a 3-chloropropyl group and a 3,3,3-trifluoropropyl group. A methyl group, a vinyl group and a phenyl group are particularly preferable. In particular, the component (B) has at least one silicon-bonded alkenyl group in one molecule, that is, at least one R in one molecule of the polyorganosiloxane resin represented by the above formula is an alkenyl group. ,
It is preferably a polyorganosiloxane resin,
Particularly, the alkenyl group is preferably a vinyl group. In this case, the other R in the polyorganosiloxane resin represented by the above formula is preferably a methyl group or a phenyl group, and in particular, at least 95 mol% of R in one molecule is a methyl group. preferable. Further, x in the above equation is a number in the range of 0.6 to 4.0.

The amount of the component (B) is 100 parts (A)
It is in the range of 1 to 50 parts by weight, preferably 1 to 30 parts by weight, particularly preferably 2 to 30 parts by weight with respect to parts by weight. This is because if the blending amount of the component (B) is less than the lower limit of the above range, the viscoelasticity of the obtained cured particulate silicone material is reduced. Is 500 μm
This is because it becomes difficult to obtain the following granular silicone cured product or the mechanical properties of the obtained granular silicone cured product are reduced.

The component (C) is the component (A) or the component (A)
It is a component for forming the cured silicone resin of the present invention by crosslinking the component and the component (B), and is a polyorganosiloxane having at least two silicon-bonded hydrogen atoms in one molecule. Examples of the bonding position of the silicon-bonded hydrogen atom include a molecular chain terminal and / or a molecular chain side chain in the component (C). Examples of the group bonded to a silicon atom other than a hydrogen atom in the component (C) include, for example,
Alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group and heptyl group; aryl groups such as phenyl group, tolyl group, xylyl group and naphthyl group; aralkyl groups such as benzyl group and phenethyl group A halogenated alkyl group such as a chloromethyl group, a 3-chloropropyl group, and a 3,3,3-trifluoropropyl group; and a methyl group and a phenyl group are particularly preferable. Examples of such a component (C) include those having a molecular structure such as linear, branched, cyclic, network, or partially branched linear. The viscosity of the component (C) at 25 ° C. is preferably in the range of 1 to 500,000 mPa · s, particularly preferably in the range of 5 to 100,000 mPa · s. This is because if the viscosity of the component (C) at 25 ° C. is less than the lower limit of the above range, the mechanical strength of the obtained cured particulate silicone material is reduced. Particle size 500μm
This is because it becomes difficult to obtain the following granular silicone cured product.

Examples of such a polyorganosiloxane as the component (C) include polymethyl hydrogen siloxane having a trimethylsiloxy group at both ends of a molecular chain and dimethylsiloxane having a trimethylsiloxy group at both ends of a molecular chain.
Methyl hydrogen siloxane copolymer, molecular chain terminal trimethylsiloxy group-blocked dimethyl siloxane / methyl hydrogen siloxane / methyl phenyl siloxane copolymer, molecular chain terminal dimethyl hydrogen siloxy group-blocked polydimethyl siloxane, molecular chain terminal dimethyl hydrogen siloxy group dimethylsiloxane-methylphenylsiloxane copolymers, both molecular terminals with dimethylhydrogensiloxy groups at polymethylphenylsiloxane, wherein: the siloxane units of the formula _{^{R 1 3 SiO 1/2: R 1}} 2 siloxane units of the formula HSiO _1/2: organosiloxane copolymers composed of siloxane units represented by SiO _4/2, wherein: the siloxane units represented by the formula R ¹ ₂ HSiO _1/2: SiO _4/2 The siloxane unit represented by Polyorganosiloxane copolymer,
The siloxane unit represented by the formula: R ¹ HSiO _2/2 and the formula: R
Siloxane unit represented by ¹ SiO _3/2 or formula: HSi
Examples thereof include an organosiloxane copolymer comprising a siloxane unit represented by O _3/2 , and a mixture of two or more of these polyorganosiloxanes. Note that R in the above equation
¹ is a monovalent hydrocarbon group other than an alkenyl group, for example, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group; a phenyl group, a tolyl group, a xylyl group, Aryl groups such as a naphthyl group; aralkyl groups such as a benzyl group and a phenethyl group; and halogenated alkyl groups such as a chloromethyl group, a 3-chloropropyl group and a 3,3,3-trifluoropropyl group.

[0013] The amount of the component (C) is determined by the component (A) or
It is an amount capable of crosslinking and curing the components (A) and (B), and specifically, 1 mole of a silicon atom-bonded alkenyl group in the component (A) or the components (A) and (B). On the other hand, the amount of silicon-bonded hydrogen atoms in the component (C) is preferably in the range of 0.5 to 10 mol. This is because the silicon-bonded hydrogen atom in the component (C) is less than the lower limit of the above range per 1 mol of the silicon-bonded alkenyl group in the component (A) or the components (A) and (B). This is because if it is present, the curing will be insufficient, while if it exceeds the upper limit of the above range, the physical properties of the obtained cured particulate silicone material will deteriorate.

The component (D) comprises the components (A) and (C),
Alternatively, a platinum-based catalyst for accelerating the curing of the components (A), (B) and (C), for example, platinum fine powder, platinum black, platinum-supported silica fine powder, platinum-supported activated carbon, Chloroplatinic acid, platinum tetrachloride, alcohol solutions of chloroplatinic acid, olefin complexes of platinum, alkenylsiloxane complexes of platinum,
Examples include carbonyl complexes of platinum.

The amount of component (D) is a catalytic amount. Specifically, the amount of platinum in component (D) is based on the total weight of components (A), (B) and (C). The metal atom is 0.1 by weight.
The amount is preferably in the range of 1 to 1,000 ppm, and particularly preferably in the range of 1 to 500 ppm. This is because if the blending amount in the component (D) is less than the lower limit of the above-mentioned range, the curing is difficult to proceed quickly, and on the other hand, even if the amount exceeds the upper limit of the above-mentioned range, the curing is not promoted. .

The cured particulate silicone of the present invention has a special viscoelasticity. Specifically, the cured particulate silicone has a characteristic that the loss tangent (tan δ) of the particulate silicone is 0.5 or less. The viscoelasticity of this granular silicone cured product can be measured using a viscoelasticity measuring device (for example, Reometric Scienti).
(ARES viscoelasticity measuring device manufactured by Fic Co., Ltd.) and the measurement is performed by sandwiching the cured particulate silicone material in a parallel plate. At that time, the storage elastic modulus G ′ (× 10 ³ dyne / cm ² ) and the loss elastic modulus G ″ (× 10 ³ dyne / cm ² ) of the cured particulate silicone can be determined. In addition,
Measurement conditions are room temperature, 25 mm parallel plate, gap: 0.5 to 0.6 mm, pressure: 700 to 1000 gf, strain: 10%, and frequency: 0.1 to 50 rad / s.

Further, the granular silicone cured product of the present invention comprises:
Since a polydiorganosiloxane such as the component (A) is blended as a component, the rubber composition has a rubbery or gel-like property, and a polyorganosiloxane resin such as the component (B) is blended. The specific gravity can be 0.98 or more, and further 0.99 or more. For this reason, it has the characteristic that it has a different viscoelasticity and feel from a hard powder represented by polymethysylsilsesquioxane powder. Further, the cured particulate silicone having such a specific gravity is characterized by having good stability in an aqueous dispersion, and is used as an additive for paints, an additive for cosmetics,
It is useful as an organic resin modifier.

Next, the method for producing the granular silicone cured product of the present invention will be described in detail. The production method of the present invention comprises: (A) 100 parts by weight of a polydiorganosiloxane having at least two silicon-bonded alkenyl groups in one molecule;
Average unit formula: (R ₃ SiO _1/2 ) _x (SiO _4/2 ) _1.0 (where R is the same or different monovalent hydrocarbon group, and x is a number of 0.6 to 4.0) And (C) a polyorganosiloxane having at least two silicon-bonded hydrogen atoms in one molecule (A) component, or (A)
An amount of the component (B) that can be cured by crosslinking with the component (B) is dispersed in water with an emulsifier, and cured with a catalytic amount of (D) a platinum-based catalyst. In the production method of the present invention, the curable silicone composition obtained by mixing the components (A) to (D) in advance may be dispersed in water with an emulsifier, and then cured. After dispersing the silicone composition comprising the components (C) and (C) in water with an emulsifier, the composition may be cured by adding the component (D) thereto. The components (A) to (D) are the same as described above.

In the production method of the present invention, the emulsifier comprises (A)
Component-A silicone composition comprising the component (C), or
It is a component for stably dispersing the curable silicone composition comprising the components (A) to (D) in water. Examples of such an emulsifier include primary to tertiary aliphatic amine salts and alkyl Cationic surfactants such as trimethylammonium salt, dialkyldimethylammonium salt, tetraalkylammonium salt, trialkylbenzylammonium salt, alkylpyridinium salt, N, N'-dialkylmonoformolinium salt, and polyethylenepolyamine fatty acid amide salt; fatty acids Salt, alkylbenzene sulfonate, alkylnaphthalene sulfonate, alkyl sulfonate, α-olefin sulfonate, dialkyl sulfosuccinate, α-sulfonated fatty acid salt, N-acyl-N-methyltaurate, alkyl sulfate , Sulfated fats and oils, polyoxyethylene Alkyl ether sulfate, polyoxyethylene alkyl phenyl ether sulfate, polyoxyethylene styrenated phenyl ether sulfate, alkyl phosphate, polyoxyethylene alkyl ether phosphate, polyoxyethylene alkyl phenyl ether phosphate, naphthalene sulfone Anionic surfactants such as acid formaldehyde condensates; N, N-dimethyl-
N-alkyl-N-carboxymethylammonium betaine, N, N-dialkylaminoalkylenecarboxylate, N, N, N-trialkyl-N-sulfoalkyleneammonium betaine, N, N-dialkyl-N, N-
Zwitterionic surfactants such as bispolyoxyethyleneammonium sulfate betaine and 2-alkyl-1-carboxymethyl-1-hydroxyethylomidazolinium betaine; polyoxyethylene alkyl ether, polyoxyethylene alkenyl ether, polyoxy Ethylene alkyl phenyl ether, polyoxyethylene polystyryl phenyl ether, polyoxyethylene / polyoxypropylene glycol, polyoxyethylene /
Polyoxypropylene alkyl ether, sorbitan fatty acid ester, glycerin fatty acid ester, decaglycerin fatty acid ester, polyglycerin fatty acid ester,
Polyhydric alcohol fatty acid partial esters such as propylene glycol / pentaerythritol fatty acid ester, propylene glycol / pentaerythritol fatty acid ester, etc., polyoxyethylene polyhydric alcohol fatty acid partial esters such as polyoxyethylene sorbitan fatty acid ester and polyoxyethylene glycerin fatty acid ester, poly Oxyethylene fatty acid ester, polyglycerin fatty acid ester, polyoxyethylated castor oil, fatty acid diethanolamide, polyoxyethylene alkylamine,
Non-ionic surfactants such as triethanolamine fatty acid partial esters, trialkylamine oxides, polyoxyalkylene group-containing polyorganosiloxanes, and mixtures of two or more of these surfactants. Preferably, it is a surfactant.

In the production method of the present invention, the component (A)
A known emulsifier can be used when emulsifying the silicone composition comprising the component (C) or the curable silicone composition comprising the components (A) to (D) in water. Examples of the emulsifier include a homogenizer and a colloid mill.

In the production method of the present invention, the component (A)
When the (C) component is dispersed in water with an emulsifier and then the (D) component is added thereto, it is preferable to add the (D) component emulsified in water with an emulsifier. . In the gender method of the present invention, the curable silicone composition obtained by previously mixing the components (A) to (D) is dispersed in water with an emulsifier, or the component (A)
The silicone composition comprising the component (C) is dispersed in water with an emulsifier, and after the component (D) is added thereto, the mixture is allowed to stand at room temperature or the dispersion of the curable silicone composition is not reduced. By heating the composition, the composition can be cured to prepare a cured particulate silicone material. The granular silicone cured product thus obtained is obtained as an aqueous dispersion, which is used as a coating additive,
It may be used as an additive for cosmetics or an organic resin modifier,
Further, water may be removed from the aqueous dispersion before use.

[0022]

Examples The granular silicone cured product of the present invention and the method for producing the same will be described in detail with reference to examples. In addition, the viscosity in an Example is a value in 25 degreeC. The average particle size and viscoelasticity of the cured particulate silicone were measured as follows. [Average particle size of cured particulate silicone] An aqueous dispersion of the cured particulate silicone was measured with a laser diffraction particle size distribution analyzer (LA-500, manufactured by Horiba, Ltd.), and the resulting median diameter (50% of the cumulative distribution) (Particle size corresponding to) was taken as the average particle size. [Viscoelasticity of cured granular silicone] Storage elastic modulus G ′ (× 10 ³ dyne / cm ² ), loss elastic modulus G ″ of cured granular silicone
(× 10 ³ dyne / cm ² ), and the loss tangent tan δ was measured using an ARES viscoelasticity measurement device (Reometric Scientific).
c). The measurement conditions were room temperature,
25mm parallel plate, gap: 0.6-0.9mm,
Pressure: 700 to 1000 gf, strain: 10%, frequency:
0.1 to 50 rad / s. [Specific Gravity of Granular Silicone Cured Product] Salt water of each specific gravity was prepared, and after confirming the specific gravity of the salt water by a floating and sedimentation method, crosslinked silicone particles were mixed and the specific gravity was determined by the floating and sinking. [Hardness of Granular Silicone Cured Product] A curable silicone composition was prepared so as to have the same composition as in Examples and Comparative Examples.
After defoaming, the mixture was placed in an oven at 150 ° C. for 30 minutes to prepare a cured silicone plate. The hardness of the silicone cured product was measured with a type A durometer specified in JIS K6253.

Example 1 63.5 parts by weight of a dimethylvinylsiloxy group-blocked methylvinylsiloxane-dimethylsiloxane copolymer (vinyl group content = 1.2% by weight) having a viscosity of 370 mPa · s on both molecular chains, Number average molecular weight is 460
0 and the average unit formula: [(CH ₃ ) ₃ SiO _1/2 ] _0.6 [CH ₂ ＣＨCH (CH ₃ ) ₂ SiO
_1/2 ] _0.1 (SiO _4/2 ) 25 parts by weight of a polyorganosiloxane resin represented by _1.0 ,
Trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer having a viscosity of 45 mPa · s at both molecular chain terminals (content of silicon-bonded hydrogen atoms = 0.43)
(% By weight) was mixed to prepare a silicone composition.

Next, 4% by weight of the silicone composition
-Polyoxyethylene nonyl phenyl ether (HLB
= 13.1) After emulsification with 53 parts by weight of an aqueous solution, 50 parts by weight of pure water was further added to prepare an emulsion of the silicone composition.

A platinum-based catalyst comprising a 1,3-divinyltetramethyldisiloxane solution containing a 1,3-divinyltetramethyldisiloxane complex of platinum as a main component is treated with polyoxyethylene nonylphenyl ether (HLB = 13.1). An emulsion of a platinum-based catalyst obtained by emulsification (average particle size of the platinum-based catalyst = 0.05 µm, platinum metal concentration = 0.05% by weight) was added to the emulsion of the silicone composition described above.
The polysiloxane component in the emulsion was uniformly mixed with platinum metal atoms in an amount of 20 ppm by weight to obtain an emulsion of a curable silicone composition.

The emulsion was allowed to stand at room temperature for one day to cure the curable silicone composition, thereby preparing an aqueous dispersion of a granular silicone cured product. The aqueous dispersion was dried with a hot air drier at 300 ° C. to recover a spherical rubber-like granular silicone cured product. Table 1 shows the properties of the granular silicone cured product.

Example 2 80 parts by weight of a methylvinylsiloxane-dimethylsiloxane copolymer (vinyl group content = 1.2% by weight) having a dimethylvinylsiloxy group at both ends of a molecular chain having a viscosity of 370 mPa · s, 80 parts by weight, number average The molecular weight is 4600, and the average unit formula is: [(CH ₃ ) ₃ SiO _1/2 ] _0.6 [CH ₂ ＣＨCH (CH ₃ ) ₂ SiO
_1/2 ] _0.1 (SiO _4/2 ) 10 parts by weight of a polyorganosiloxane resin represented by _1.0 ,
Trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer having a viscosity of 45 mPa · s at both molecular chain terminals (content of silicon-bonded hydrogen atoms = 0.43)
(% By weight) to prepare a silicone composition.

Next, this silicone composition was added in an amount of 1% by weight.
-Polyoxyethylene nonyl phenyl ether (HLB
= 13.1) After emulsification with 53 parts by weight of an aqueous solution, 50 parts by weight of pure water was further added to prepare an emulsion of the silicone composition.

Platinum obtained by emulsifying a platinum-based catalyst comprising a 1,3-divinyltetramethyldisiloxane solution containing a 1,3-divinyltetramethyldisiloxane complex of platinum as a main component in water with polyoxyethylene nonylphenyl ether The emulsion of the catalyst (average particle size of the platinum catalyst = 0.05 µm, the concentration of platinum metal = 0.05% by weight) was added to the emulsion of the silicone composition and the polysiloxane component in the emulsion was mixed with platinum. The metal was uniformly mixed in an amount of 20 ppm by weight to obtain an emulsion of the curable silicone composition.

The emulsion was allowed to stand at room temperature for one day to cure the curable silicone composition to prepare an aqueous dispersion of a cured spherical silicone product. The aqueous dispersion was dried with a hot air drier at 300 ° C. to recover a spherical rubber-like granular silicone cured product. Table 1 shows the properties of the granular silicone cured product.

Example 3 85.5 parts by weight of a methylvinylsiloxane-dimethylsiloxane copolymer (vinyl group content = 1.2% by weight) having a dimethylvinylsiloxy group at both ends of the molecular chain having a viscosity of 370 mPa · s. Number average molecular weight of 4,60
0, and 5 parts by weight of a polyorganosiloxane resin represented by an average unit formula: [(CH ₃ ) ₃ SiO _1/2 ] _0.7 (SiO _4/2 ) _1.0 , and trimethylsiloxy at both ends of a molecular chain having a viscosity of 45 mPa · s. Group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer (content of silicon-bonded hydrogen atoms = 0.
(43% by weight) was mixed with 9.5 parts by weight to prepare a silicone composition.

Next, this silicone composition was added in an amount of 3% by weight.
-Polyoxyethylene nonyl phenyl ether (HLB
= 13.1) After emulsification with 53 parts by weight of an aqueous solution, 50 parts by weight of pure water was further added to prepare an emulsion of the silicone composition.

Platinum obtained by emulsifying a platinum-based catalyst comprising a 1,3-divinyltetramethyldisiloxane solution containing a 1,3-divinyltetramethyldisiloxane complex of platinum as a main component in water with polyoxyethylene nonylphenyl ether The emulsion of the catalyst (average particle size of the platinum catalyst = 0.05 µm, the concentration of platinum metal = 0.05% by weight) was added to the emulsion of the silicone composition and the polysiloxane component in the emulsion was mixed with platinum. The metal was uniformly mixed in an amount of 20 ppm by weight to obtain an emulsion of the curable silicone composition.

The emulsion was allowed to stand at room temperature for one day to cure the curable silicone composition to prepare an aqueous dispersion of a cured particulate silicone material.

Next, the aqueous dispersion was dried by a hot air drier at 300 ° C. to recover a spherical rubber-like granular silicone cured product. Table 1 shows the properties of the granular silicone cured product.

Comparative Example 1 90 parts by weight of a dimethylvinylsiloxy-group-blocked methylvinylsiloxane-dimethylsiloxane copolymer (vinyl group content = 1.2% by weight) having a viscosity of 370 mPa · s and a viscosity of 45 mPa. A silicone composition was prepared by mixing 10 parts by weight of a dimethylsiloxane-methylhydrogensiloxane copolymer (content of silicon-bonded hydrogen atoms = 0.43% by weight) with both ends of a trimethylsiloxy group capped at both molecular chains of s. .

Next, 1% by weight of the silicone composition
-Polyoxyethylene nonyl phenyl ether (HLB
= 13.1) After emulsification with 53 parts by weight of an aqueous solution, 50 parts by weight of pure water was further added to prepare an emulsion of the silicone composition.

A platinum-based catalyst comprising a 1,3-divinyltetramethyldisiloxane solution containing a 1,3-divinyltetramethyldisiloxane complex of platinum as a main component is treated with polyoxyethylene nonylphenyl ether (HLB = 13.1). An emulsion of a platinum-based catalyst emulsified in water (average particle size of the platinum-based catalyst = 0.05 µm, platinum metal concentration = 0.
Of the curable silicone composition is uniformly mixed with the above silicone composition emulsion in an amount such that platinum metal is 20 ppm by weight based on the polysiloxane component in the emulsion. And

The emulsion was allowed to stand at room temperature for one day to cure the curable silicone composition, thereby preparing an aqueous dispersion of the granular silicone cured product.

Next, the aqueous dispersion was dried by a hot air drier at 300 ° C. to recover a spherical rubber-like cured silicone particle. Table 1 shows the properties of the granular silicone cured product.

Comparative Example 2 Methyltrimethoxysilane was hydrolyzed in an aqueous potassium hydroxide solution to prepare polymethylsilsesquioxane fine particles, which were washed with water.
After drying, the primary particles were further pulverized by a jet mill to prepare spherical polymethylsilsesquioxane fine particles.

[0042]

[Table 1]

[Feeling of Skin of Granular Silicone Cured Product]
The feel when the granular silicone cured product was spread on the back of the hand with a finger was observed. As a result, the cured particles of silicone in Examples 1 to 3 spread well on the skin and had a good feel.
On the other hand, the cured particulate silicone in Comparative Example 1 had a slightly hard feel to the skin, and the cured particulate silicone in Comparative Example 2 had a rough and hard feel when spread, had poor smoothness, and was difficult to spread.

[0044]

The cured particulate silicone of the present invention has a special viscoelasticity and good touch feeling, and the method for producing the cured particulate silicone of the present invention is characterized in that There is a feature that a silicone cured product can be efficiently produced.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court II (Reference) C08L 83:05) (72) Inventor Takashi Tachibana 2-2 Chigusa Beach, Ichihara-shi, Chiba Dow Corning Toray Toray F-term in R & D Co., Ltd. (Reference) 4J002 CP032 CP043 CP131 CP141 DA116 DD046 EZ006 FD206 GB00 GH00

Claims (4)

[Claims] (A) 100 parts by weight of a polydiorganosiloxane having at least two silicon-bonded alkenyl groups in one molecule, (B) average unit formula: (R ₃ SiO _1/2 ) _x (SiO _{4 / 2} ) _{1.0 to} 1 part by weight of a polyorganosiloxane resin represented by _1.0 (where R is the same or different monovalent hydrocarbon group, and x is a number from 0.6 to 4.0), And (C) a polyorganosiloxane having at least two silicon-bonded hydrogen atoms in one molecule {component (A), or (A)
The amount by which the component and the component (B) can be cured by cross-linking is determined by a catalytic amount of the (D) platinum-based catalyst.
A granular cured silicone having a particle size of 1 to 500 μm. 2. The cured particulate silicone according to claim 1, wherein the component (B) is a polyorganosiloxane resin having at least one alkenyl group in one molecule. (A) 100 parts by weight of a polydiorganosiloxane having at least two silicon-bonded alkenyl groups in one molecule, (B) average unit formula: (R ₃ SiO _1/2 ) _x (SiO _{4 / 2} ) _{1.0 to} 1 part by weight of a polyorganosiloxane resin represented by _1.0 (where R is the same or different monovalent hydrocarbon group, and x is a number from 0.6 to 4.0), And (C) a polyorganosiloxane having at least two silicon-bonded hydrogen atoms in one molecule {component (A), or (A)
2. The granular silicone cured product according to claim 1, wherein the amount of the component and the component (B) that can be cured by crosslinking is dispersed in water with an emulsifier and cured with a catalytic amount of a (D) platinum-based catalyst. How to manufacture. 4. The method for producing a cured particulate silicone according to claim 3, wherein the component (B) is a polyorganosiloxane resin having at least one alkenyl group in one molecule.