JPH0912891A - Organopolysiloxane composition, surface treatment, and silicone rubber parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a cured film which can form a matte surface and impart a design and has excellent abrasion resistance by coating the surface of a silicone rubber substrate with a particular organopolysiloxane compsn. and heating the coating. SOLUTION: 100 pts.wt. organopolysiloxane (i), having at least two alkenyl groups per molecule, represented by R<1> a R<2> b SiO(4-a-b)/2 (R<1> represents a monovalent hydrocarbon group; R<2> represents an alkenyl group; a is 1.6 to 2.05; b is 0.001 to 0.5; and a+b=1.85 to 2.1), a hydrogenpolysiloxane (ii), having at least two hydrogen atoms per molecule, represented by R<3> c Hd SiO(4-c-d)/2 (R3 represents a monovalent hydrocarbon group; c is 0.8 to 2; d is 0.01 to 1; and c+d=0.85 to 2.5) in such an amt. as will give 0.4 to 10 hydrogen atoms per alkenyl group in the component (i), 2 to 50 pts.wt., based on 100 pts.wt. in total of the components (i) and (ii), polycarbonate resin power (iii) having an average particle, diameter of not more than 50μm, and a catalytic amt. of platinum or a platinum compd. (iv) are mixed together to prepare an organopolysiloxane compsn.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is capable of imparting a design property to a surface of silicone rubber and forming a film having excellent wear durability, and is subjected to surface treatment of silicone rubber, particularly subjected to repeated frictional force over a long period of time. Such applications, eg O
An organopolysiloxane composition that can be suitably used as a surface treatment agent for equipment A key tops, rubber contacts, etc., a surface treatment agent effective for silicone rubber, and a coating film formed by curing this composition on the silicone rubber surface. It relates to a formed silicone rubber part.

[0002]

2. Description of the Related Art Generally, a silicone rubber material has a glossy surface and is inferior in a high-grade appearance. Therefore, when it is used in an application where designability is required,
Surface treatment is applied to deluster.

Here, a silicone-based curable composition is often used as the surface treatment agent from the viewpoint of adhesiveness to the base rubber. In order to make the cured film of this silicone-based curable composition matte, it is necessary to add a large amount of inorganic powder such as silica, diatomaceous earth, calcium carbonate, alumina, etc. In addition to deteriorating the physical properties of (1) and (3), the adhesiveness with the base rubber is impaired, so that there is a problem that the wear resistance of the cured film is significantly reduced. In addition, when the viscosity of the silicone-based curable composition is low or when it contains a solvent, there is a problem that the inorganic powder is precipitated and aggregated, and redispersion becomes difficult.

Further, polymethylsilsesquioxane powder has been proposed as a matting additive other than the above-mentioned inorganic powder (Japanese Patent Laid-Open No. 4-161468, Japanese Patent Publication No. 4-22).
No. 189), the composition added with this powder is improved in the dispersibility of the powder and is good, but it is disadvantageous in terms of cost, and the wear resistance of the cured film is also unsuitable for use in which repeated friction is applied. It is enough. Further, when a solvent is used, there is a problem that polymethylsilsesquioxane precipitates.

The present invention has been made in order to solve the above-mentioned problems, and it provides a cured film excellent in abrasion resistance as well as capable of delustering the surface of the silicone rubber to give good designability. It is an object of the present invention to provide an organopolysiloxane composition that can be formed, a surface treatment agent effective for silicone rubber, and a silicone rubber component having a coating film formed by the composition formed on the surface of the silicone rubber.

[0006]

The present inventor has set forth the above-mentioned object.
As a result of repeated diligent studies to achieve the purpose, the following average group
Formula (1) R¹ _aR^Two _bSiO_{(4-ab) / 2} (1) (where R¹Is a substitution or a bond containing no aliphatic unsaturated bond.
Is an unsubstituted monovalent hydrocarbon group, R^Two Is arche Is a nyl group
, A is 1.6 to 2.05, b is 0.001 to 0.5
And a positive number that satisfies a + b = 1.85 to 2.1.
You. ), An alkane bonded to a silicon atom in one molecule
Organopolysiloxane containing at least two kenyl groups
Sun and the following average composition formula (2) R^Three _cH_dSiO_{(4-cd) / 2} (2) (where R^ThreeIs a substitution or a bond containing no aliphatic unsaturated bond.
Is an unsubstituted monovalent hydrocarbon group, c is 0.8 to 2, d
Is 0.01 to 1 and c + d = 0.85 to 2.5 is satisfied.
It is a positive number. ) With a silicon atom in one molecule
Organohai having at least two hydrogen atoms bonded
From drogene polysiloxane and platinum or platinum compound
Addition reaction curable organopolysiloxane composition
As a matting agent, a polycarbonate with an average particle size of 50 μm or less
By adding a predetermined amount of carbonate resin powder,
The corn rubber surface can be delustered to add design.
Hardened film that is not only durable but also wear-resistant
To obtain an organopolysiloxane composition
The silicone rubber surface is a coating film formed by curing
By coating the surface, silicone
Is obtained, and therefore the above organopolysiloxane
The xanthane composition has a repetitive frictional force especially over a long period of time.
Applications that receive it, such as key tops and mules for office automation equipment
-Can be suitably used as a surface treatment agent for contacts, etc.
As a result, the present invention has been completed.

Therefore, the present invention provides [A] (1) 100 parts by weight of organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule represented by the above average composition formula (1) (2) An organohydrogenpolysiloxane having at least two hydrogen atoms bonded to a silicon atom in one molecule represented by the above average composition formula (2) is added to one alkenyl group in the organopolysiloxane component of the above formula (1). On the other hand, an amount that gives 0.4 to 10 hydrogen atoms bonded to silicon atoms in the organohydrogenpolysiloxane component. (3) Polycarbonate resin powder having an average particle size of 50 μm or less is added to the organopolysiloxane of the above formula (1). 2 to 50 parts by weight per 100 parts by weight of the total amount of the siloxane and the organohydrogenpolysiloxane of the above formula (2) (4) Platinum or platinum compound
An organopolysiloxane composition containing a catalyst amount, [B] a surface treatment agent comprising the above organopolysiloxane composition, and [C] a coating film obtained by curing the above organopolysiloxane composition. Provides a silicone rubber part formed on a silicone rubber surface.

The present invention will be described in more detail below.
And the first component of the organopolysiloxane composition of the present invention
Is the following average composition formula (1) R¹ _aR^Two _bSiO_{(4-ab) / 2} (1) (where R¹Is a substitution or a bond containing no aliphatic unsaturated bond.
Is an unsubstituted monovalent hydrocarbon group, R^Two Is arche Is a nyl group
, A is 1.6 to 2.05, b is 0.001 to 0.5
And a positive number that satisfies a + b = 1.85 to 2.1.
Preferably, a is 1.8 to 2.0 and b is 0.005.
0.1 and a + b = 1.9 to 2.04. ) Indicated by
The number of alkenyl groups bonded to silicon atoms in one molecule is small.
It is an organopolysiloxane having at least two.

In the above formula (1), R ¹ may be the same or different and is a substituted or unsubstituted monovalent hydrocarbon group containing no aliphatic unsaturated bond, preferably having 1 to 1 carbon atoms.
12, more preferably those having 1 to 8 carbon atoms, for example, methyl group, ethyl group, propyl group, isopropyl group,
Butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, octyl group, decyl group, dodecyl group and other alkyl groups, cyclopentyl group,
Cycloalkyl group such as cyclohexyl group, cycloheptyl group, aryl group such as phenyl group, tolyl group, xylyl group, naphthyl group, aralkyl group such as benzyl group, phenylethyl group, phenylpropyl group, and hydrogen atom of these groups A part or all of which is substituted with a halogen atom such as fluorine, bromine or chlorine, or a cyano group, such as a chloromethyl group, a chloropropyl group, a bromoethyl group, a trifluoropropyl group, a cyanoethyl group, and the like. Among them, all are preferably methyl groups from the viewpoint of chemical stability and ease of synthesis. In addition, a part of the methyl group may be substituted with a phenyl group, a trifluoropropyl group, or the like, if necessary for the characteristics. R ^{2 s} may be the same or different, for example, a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, a pentenyl group and the like, usually having 2 to 8 carbon atoms, especially carbon atoms. Number 2
Alkyl groups of 4 to 4, particularly vinyl group and allyl group are preferred, and vinyl group is most preferred from the viewpoint of ease of synthesis and chemical stability.

The at least two alkenyl groups contained in the molecule may be bonded to any silicon atom at the end of the molecular chain or in the middle of the molecular chain. It is preferable that the compound has an alkenyl group bonded to, from the viewpoint of the curing rate or the physical properties of the cured product.

The above-mentioned organopolysiloxane is 2
Viscosity at 5 ° C. is preferably 100 cs (centistokes) or more, and particularly preferably in the range of 400 to 500,000 cs. When the viscosity is lower than 100 cs, the film after curing becomes brittle and the substrate cannot be deformed. However, if it exceeds 500,000 cs, the viscosity of the composition before curing becomes large, the handling becomes inconvenient, and it may be necessary to use a large amount of solvent. As the organopolysiloxane, if the viscosity is within the above range, two or more kinds of components may be used in combination.

The average degree of polymerization of the above organopolysiloxane, that is, the number of silicon atoms in the molecule is usually 150 to 20.
About 00 is suitable.

Further, the molecular structure of the above-mentioned organopolysiloxane may be any of linear, branched, cyclic or three-dimensional network structure, but normally, the main chain is basically a repeating diorganosiloxane unit. It is generally a linear diorganopolysiloxane having a molecular chain end blocked with a triorganosiloxy unit.

Next, the second component, organohydrogenpolysiloxane, has at least two, preferably three or more hydrogen atoms bonded to silicon atoms in one molecule, and has the following average composition formula (2). R ³ _c H _d SiO _{(4-cd) / 2} (2) (wherein, R ³ is a substituted or unsubstituted monovalent hydrocarbon group containing no aliphatic unsaturated bond, and c is 0.8 ~ 2, d
Is a positive number satisfying 0.01 to 1 and c + d = 0.85 to 2.5, and preferably c is 1 to 1.95, d is 0.02 to 0.5, and c + d = 1. .3 to 2.3. )
It is shown by.

The above-mentioned organohydrogenpolysiloxane acts as a cross-linking agent, and in the presence of the platinum-based catalyst of the fourth component, the silicon-bonded hydrogen atom of the second component of the organohydrogenpolysiloxane is the first component. It undergoes an addition reaction with a silicon atom-bonded alkenyl group of the organopolysiloxane, and as a result, a cured film having a three-dimensional network structure is provided.

In the organohydrogenpolysiloxane of the above formula (2), the substituent other than the silicon atom-bonded hydrogen atom, that is, R ³ , is the same as R ¹ above, usually having 1 to 12 carbon atoms, preferably C ³ Those of 1 to 8 are exemplified. R ³ may be the same or different, but from the viewpoint of ease of synthesis and chemical stability, it is preferable that all R ³ are methyl groups, and if necessary for the characteristics, part of the methyl groups is phenyl group or trifluoropropyl group. It may be substituted with a group or the like.

The organohydrogenpolysiloxane of the above formula (2) has at least two, preferably three or more hydrogen atoms (SiH groups) bonded to a silicon atom in one molecule. The compound may be bonded to a silicon atom at the terminal of the molecular chain or may be bonded to a silicon atom in the middle of the molecular chain.

The above-mentioned organohydrogenpolysiloxane is not particularly limited in its molecular structure and, for example, basically 2
Valency siloxane units

[0019]

Embedded image Of monovalent siloxy units

[0020]

Embedded image It is possible to use those having a linear structure blocked with, a cyclic structure composed of divalent siloxane units, or a branched or three-dimensional network structure (resinous material). A polysiloxane is a polymer composed of only siloxane units having a silicon-hydrogen bond, and a copolymer containing one or more of triorganosiloxy units, diorganosiloxane units, monoorganosiloxysan units and SiO ₂ units. It may be a combination.

The degree of polymerization of the organohydrogenpolysiloxane is not particularly limited, but the number of silicon atoms in one molecule is usually 300 in view of compatibility with the first component and ease of synthesis. In the following, it is particularly preferable that the number is about 4 to 150, and that the viscosity at 25 ° C. is 500 cs or less, usually about 0.5 to 300 cs.

The content of the organohydrogenpolysiloxane as the second component is contained in the organohydrogenpolysiloxane component with respect to one silicon atom-bonded alkenyl group contained in the organopolysiloxane component as the first component. Number of hydrogen atoms bonded to silicon atom is 0.4
The range is 10 to 10, preferably 1 to 5. If the number of silicon atom-bonded hydrogen atoms is less than 0.4, the curing will be insufficient and the required film strength will not be obtained, and if it is more than 10, it will cause foaming during curing or cause a change in physical properties over time. I will end up.

The polycarbonate resin powder having an average particle diameter of 50 μm or less as the third component not only eliminates the gloss of the cured film obtained from the composition of the present invention, but also reduces the tackiness of the surface of the film, and further, It is intended to improve wear resistance.

The average particle size of the above polycarbonate resin powder must be 50 μm or less, preferably 0.3 to 40 μm, and when the average particle size exceeds 50 μm,
Not only the mechanical strength of the cured film is reduced, but also the wear resistance is reduced. If the average particle size is smaller than 0.3 μm, not only the production is difficult, but also it is difficult to uniformly disperse, and the effect of adding the component may not be obtained.

Further, the shape of the polycarbonate resin powder having the above-mentioned average particle diameter is preferably spherical or scaly, but may be a polyhedron, a polyhedron, or a single body.

The blending amount of the above-mentioned polycarbonate resin powder is 100 parts by weight of the above-mentioned first and second components (parts by weight,
The same applies hereinafter) to 2 to 50 parts, particularly 5 to 30 parts. If the amount is less than 2 parts, the desired effect will not be exhibited, and if it exceeds 50 parts, the mechanical strength of the cured film will be poor, and the abrasion resistance will be markedly reduced.

Next, the fourth component platinum or platinum compound is
It is used as a catalyst for promoting the addition reaction between the above-mentioned first component organopolysiloxane and the second component organohydrogenpolysiloxane.

Here, as the platinum compound, known compounds can be used. Specifically, platinum black, chloroplatinic acid, an alcohol modified product of chloroplatinic acid, platinum and olefin, aldehyde, vinyl siloxane or acetyl alcohol. And the like.

The addition amount of platinum or a platinum compound may be a catalytic amount and may be appropriately increased or decreased according to a desired curing rate, but usually 0.1 atom amount of platinum based on the first component.
The range of up to 1000 ppm, especially 1 to 300 ppm, is suitable. If it is less than 0.1 ppm, the catalytic function may not be sufficiently exhibited and curing may be poor, and if it exceeds 1000 ppm, it may be economically disadvantageous.

The composition of the present invention comprises the above-mentioned first to fourth components.
Can be obtained by mixing a predetermined amount of
Within the range that does not impair the object of the present invention, further
Add fillers, pigments, adhesion aids, reaction control agents, etc.
You may. In addition, non-functional di-
Methyl polysiloxane, especially high viscosity dimethyl polysiloxane
Xan may be added. Specifically as a filler, smoke
Atomized silica, precipitated silica and their hydrophobized products, various silica
Reinforcing filler such as silicone resin and organic resin, silica air
Examples of non-reinforcing fillers such as rogel, ground quartz and diatomaceous earth
Can be shown, one of these alone or two or more
Can be mixed and used. Reinforcing filler
Examples of the silicone resin include R _ThreeSiO_1/2
Unit and SiO_TwoUnit and / or RSiO_3/2Unit (R in the formula
Is R¹Monovalent, which does not contain aliphatic unsaturated bonds similar to
It is a group selected from a hydrocarbon group and a vinyl group. From)
Become essential, SiO_TwoR for unit _ThreeSiO_1/2unit
Has a molar ratio of 0.4 to 1.2, preferably about 0.5 to 1.
Silicone resin, etc., and if necessary, the first component
0 to 100 parts, especially 10 to 50 parts per 100 parts
Can be blended.

The pigment is, for example, an inorganic pigment such as carbon black, iron oxide, titanium oxide or zinc oxide, and the adhesion aid is, for example, tetraalkoxysilanes such as tetramethoxysilane or tetraethoxysilane or trimethoxysilane. , Triethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, and other trialkoxysilanes and their partial hydrolysates, α-silyl esters, γ-glycidoxypropyl Trimethoxysilane, γ-glycidoxypropyltriethoxysilane,
Reaction control agents such as alkoxysilanes containing an epoxy functional group such as β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane include vinyl siloxanes, acetylene alcohols, silanes or siloxanes containing an ethynyl group, tris Allyl isocyanurate or the like can be added. When the above-mentioned vinyl group-containing silicone resin and / or vinyl siloxane is added as an additive, one unsaturated bond of the alkenyl group bonded to the silicon atom in the entire composition is directly bonded to the silicon atom. It is necessary to make 0.4 to 10 hydrogen atoms exist.

An ultraviolet absorber may be added to the composition of the present invention. As the ultraviolet absorber, for example, carbon black or benzotriazole may be added. In addition, the addition amount of these optional components can be a usual amount as long as the effect of the present invention is not hindered.

The composition of the present invention can be easily prepared by uniformly mixing the above-mentioned components, but the reaction of the first component and the second component proceeds immediately in the presence of the fourth component. Therefore, it is preferable to store it in two packages before use. For example, a part of the first component, the third component and the fourth component are packaged in one package, the rest of the first component and the second component are packaged in another package, and these two packages are used in a prescribed amount by a proper method at the time of use. Mixing is preferred. When acetylene alcohol, ethynyl group-containing silane or siloxane is used as the reaction control agent, it can be stored as one package.

The composition of the present invention can be used for treating various silicone rubber substrates by the method described below. That is, the organopolysiloxane composition of the present invention as it is or after being diluted with an organic solvent to a solution state, dip coating, spray coating, brush coating, knife coating, roll coating, on the surface of the silicone rubber substrate.
It can be applied by a method such as screen printing.

In this case, as the organic solvent, for example, n-
Examples include hexane, n-heptane, cyclohexane, industrial gasoline, petroleum naphtha, isoparaffin, benzene, toluene, xylene, isopropyl alcohol, butyl alcohol, cyclohexanone, methyl ethyl ketone, low molecular weight siloxane, cyclic siloxane, and mixtures thereof. Among these, industrial gasoline, petroleum naphtha, isoparaffin, toluene, xylene, low-molecular-weight siloxane, or a mixture thereof with one or two of three solvents selected from isopropyl alcohol, methyl ethyl ketone or cyclohexanone is preferable. Used for. The amount of such organic solvent used can be appropriately selected according to the desired viscosity of the composition.

Further, when diluted with an organic solvent,
After they are dried and removed, a coating film of silicone rubber can be obtained by heating and curing at a temperature of 60 to 200 ° C. for about 30 seconds to 120 minutes.

[0037]

EFFECTS OF THE INVENTION The organopolysiloxane composition of the present invention can make the surface of a silicone rubber matte and give it a good design when the surface of various silicone rubber substrates is coated and treated. In addition, when compared with the conventional treatment with the organopolysiloxane composition, a cured film having particularly excellent abrasion resistance can be provided. Therefore, the composition of the present invention is particularly suitable as a surface treatment agent for forming a film having excellent wear durability, and is used in applications where frictional force is repeatedly applied for a long period of time, such as key tops of OA equipment and rubber contacts. Can be suitably used as a surface treatment agent for

[0038]

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. All parts in each example are parts by weight.

[Examples 1 and 2] The viscosity at 25 ° C was 10
Linear dimethylpolysiloxane 350 having a molecular chain end of 30,000 cs blocked with a trivinylsilyl group
Part, (CH ₃ ) ₃ SiO _0.5 unit, (CH ₂ = CH) (CH
₃ ) ₂ SiO _0.5 units and SiO ₂ units,
H _{3) 3} and SiO _0.5 units _{(CH 2 = CH) (CH} 3) 2 Si
A xylene solution of methylvinylpolysiloxane resin having a total of _0.5 units of O based on SiO ₂ units of 0.8 and a vinyl value of 0.08 mol per 100 g (50% by weight).
300 parts, 70 parts of scale-like polycarbonate resin powder having an average particle diameter of 25 μm, 0.9 part of a solution of chloroplatinic acid in n-octyl alcohol (2% by weight as platinum metal concentration), 3
- methyl-1-butyn-3-ol 0.3 parts of average formula (CH _{3) 3} SiO [(CH ₃₎ HSiO] ₃₈ Si (C
A mixture of 20 parts of organohydrogenpolysiloxane represented by H ₃ ) ₃ was uniformly mixed using a planetary mixer to obtain an organopolysiloxane composition. Next, 500 parts of xylene was added to this composition to obtain a xylene solution of the organopolysiloxane composition (Example 1).

A part of the xylene solution of the obtained composition was transferred to another container and allowed to stand at room temperature (25 ° C.) for 30 days.
Upon re-stirring, the polycarbonate resin powder could be easily dispersed uniformly in the solution.

Further, a xylene solution of the organopolysiloxane composition was obtained in the same manner as in Example 1 except that the compounding amount of the above polycarbonate resin powder was 35 parts (Example 2).

After the treatment liquid of each organopolysiloxane composition prepared in Examples 1 and 2 above was cured on a vulcanized and cured silicone rubber plate, it was applied (knife coat) to a thickness of 10 μm for 5 minutes. When air-dried and then heat-cured at 180 ° C. for 300 seconds, a non-adhesive and robust cured film was obtained.

[Comparative Examples 1 and 2] A cured film was formed in the same manner as in Example 1 except that the polycarbonate resin powder was not used (Comparative Example 1).

A cured film was formed in the same manner as in Example 1 except that 70 parts of spherical powder of polymethylsilsesquioxane (average particle diameter 1.2 μm) was used in place of the polycarbonate resin powder (Comparative Example). 2).

The cured film obtained was measured for glossiness and evaluated for abrasion resistance by the following methods. Table 1 shows the results. Gloss: The gloss is IG-31, a gloss meter manufactured by HORIBA, Ltd.
0 was used, and measurement was performed under the conditions of an incident angle of 60 ° and a light receiving angle of 60 °. Abrasion resistance: The abrasion resistance test was conducted under the following conditions. Test conditions: Tester Reciprocating abrasion tester Friction element Sand eraser (SH502 manufactured by Lion Corporation) Load 500g Stroke 25mm Friction cycle 700 reciprocations / min For abrasion resistance, check the abrasion state of the cured coating every 70 times. The evaluation was made by the number of times of friction until the cured film peeled from the substrate or the film itself was abraded and the substrate started to rub. The numerical values in Table 1 indicate that the base material started to be worn after that number of times (next check).

From the results shown in Table 1, the organopolysiloxane composition of the present invention can make the surface of the silicone rubber matte and is excellent in abrasion resistance as compared with the conventional treatment with the organopolysiloxane composition. It was confirmed that it gives a cured film.

[0047]

[Table 1] * Amount of the 1st component relative to 100 parts of organopolysiloxane ** PMS (polymethylsilsesquioxane)

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location C09D 183/05 C09D 183/05 183/07 PMU 183/07 PMU (72) Inventor Kazumi Okada Matsui Usui-gun Gunma Prefecture Tamachi Daiji Hitomi 1-10 Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Technology Laboratory

Claims (3)

[Claims] 1. The following average composition formula (1) R¹ _aR^Two _bSiO_{(4-ab) / 2} (1) (where R¹Is a substitution or a bond containing no aliphatic unsaturated bond.
Is an unsubstituted monovalent hydrocarbon group, R^Two Is arche Is a nyl group
, A is 1.6 to 2.05, b is 0.001 to 0.5
And a positive number that satisfies a + b = 1.85 to 2.1.
You. ), Which is bonded to a silicon atom in one molecule
Organopolysiloxa having at least two kenyl groups
100 parts by weight (2) The following average composition formula (2) R^Three _cH_dSiO_{(4-cd) / 2} (2) (where R^ThreeIs a substitution or a bond containing no aliphatic unsaturated bond.
Is an unsubstituted monovalent hydrocarbon group, c is 0.8 to 2, d
Is 0.01 to 1 and c + d = 0.85 to 2.5 is satisfied.
It is a positive number. ) With a silicon atom in one molecule
Organohai having at least two hydrogen atoms bonded
The drogen polysiloxane is replaced with the organo of formula (1) above.
For one alkenyl group in the polysiloxane component,
Silicon source in Luganohydrogenpolysiloxane component
Amount to give 0.4 to 10 hydrogen atoms bonded to the child (3) Polycarbonate resin having an average particle size of 50 μm or less
The fat powder was mixed with the organopolysiloxane of formula (1) above.
With the organohydrogenpolysiloxane of formula (2)
2 to 50 parts by weight relative to the total amount of 100 parts by weight (4) Platinum or platinum compound
 Characterized by containing a catalytic amount
Organopolysiloxane composition. 2. A surface treatment agent comprising the organopolysiloxane composition according to claim 1. 3. A silicone rubber part having a coating film formed by curing the organopolysiloxane composition according to claim 1 formed on the surface of the silicone rubber.