JP2010180382A - Ambient temperature-curing organopolysiloxane composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dealcoholizing one-pack type ambient temperature-curing organopolysiloxane composition which is low in transmission oil foaming and gives a seal of excellent oil resistance. <P>SOLUTION: The low-foaming ambient temperature-curing organopolysiloxane composition includes the following components (A)-(E): (A) 100 pts.mass diorganopolysiloxane having at least two silanol groups or an alkoxy group in the molecule and a degree of polymerization of not smaller than 10, (B) 10-300 pts.mass inorganic filler, (C) 1-30 pts.mass alkoxy silane represented by general formula (7): R<SP>1</SP><SB>4-n</SB>Si(OR)<SB>n</SB>, its partial hydrolysate or their combination (wherein R is a mutually independently 1-4C alkyl group, R<SP>1</SP>is a mutually independent substituted or unsubstituted 1-20C monovalent group and n is an integer of 2-4), (D) 0.01-15 pts.mass curing catalyst and (E) 0.05-15 pts.mass silane coupling agent. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a room temperature curable organopolysiloxane composition and an automobile oil seal obtained by curing the composition. Even when the composition is mixed in the transmission oil of an automatic vehicle, the degree of foaming of the oil is low. Further, the cured product of the composition is excellent in oil resistance and chemical resistance, and is suitably used as an automobile oil seal.

Conventionally, oil-resistant solid gaskets and packing materials made of cork, organic rubber, asbestos, and the like have been used for various oil seals for automobile engines. However, these materials have the disadvantage of complicated inventory management and work processes. Further, the sealing performance has a drawback of low reliability.

Therefore, instead of the solid gasket, a sealing method called FIPG (Formed In Place Gaskets) method using room temperature curable silicone rubber is employed. This is a one-part room temperature curable organopolysiloxane composition applied to the seal surface of the engine block when the engine is assembled, and the seal surfaces are bonded together and bolted while the composition is uncured. It is. This method is excellent in workability and excellent in the sealing property and heat resistance of the sealing material.

An engine assembled while applying an oil seal according to the FIPG method is usually subjected to a start test by injecting oil immediately after assembly. However, the room temperature curable organopolysiloxane composition requires a relatively long time for curing. Therefore, part of the organopolysiloxane composition is dispersed or dissolved in the oil during the start-up test. In particular, when dispersed or dissolved in automatic transmission oil (ATF) and continuously variable transmission oil (CVT), the oil is bubbled due to the complicated structure of the transmission, and the oil at the top of the engine There may be a problem that oil is ejected from the inlet. Therefore, a low-foaming one-component room temperature curable organopolysiloxane composition is desired.

Various measures for foaming have been studied. For example, there are a method of adding isocyanate silane to the composition (Patent Document 1) and a method of adding aminosiloxane (Patent Documents 2 and 3). However, since any of these suppresses foaming by eluting the additive component into the oil, the performance of the oil may be reduced. Moreover, the oil resistance of the oil seal obtained from the composition was not sufficient.

Other methods include a method of blending alkoxysilane and aluminum stearate in the gasket composition (Patent Document 4) and a method of blending a specific silane coupling agent (Patent Document 5). According to these methods, there is almost no influence on the oil. However, the effect of reducing foaming is insufficient, and the oil resistance of the seal is not sufficient.

Japanese Patent Laid-Open No. 08-73745 Japanese Patent Laid-Open No. 02-215862 Japanese Patent Laid-Open No. 02-67364 Japanese Patent Laid-Open No. 03-17157 Japanese Patent Laid-Open No. 09-124946

  Accordingly, the present inventors have studied for the purpose of providing a dealcohol-free one-part room temperature curable organopolysiloxane composition that provides a seal with less foaming of transmission oil and excellent oil resistance. The cause of this is that a substance having a hydroxyl group contained in the transmission oil reacts with a silicon compound having a hydrolyzable group contained in the composition to produce a substance in which the oil component and the silicon compound are bonded to each other. The knowledge that it acts as an activator was obtained. Based on this finding, when alkoxysilane, which has a relatively slow reaction with the above-mentioned substance having a hydroxyl group, was used, reduction of foaming was achieved. Furthermore, the oil resistance of the oil seal was improved by blending a silane coupling agent component.

That is, the present invention is a low-foaming room temperature curable organopolysiloxane composition comprising the following components (A) to (E).
(A) Diorganopolysiloxane having at least two silanol groups or alkoxy groups per molecule and having a polymerization degree of 10 or more 100 parts by mass (B) Inorganic filler 10 to 300 parts by mass (C) The following general formula ( 7) Alkoxysilane, a partial hydrolyzate thereof, or a combination thereof R ¹⁴ _-n Si (OR) _n (7)

Wherein R is independently an alkyl group having 1 to 4 carbon atoms, R ¹ is independently a substituted or unsubstituted monovalent group having 1 to 20 carbon atoms, and n is independently 1 to 30 parts by mass (D) curing catalyst 0.01 to 15 parts by mass (E) silane coupling agent 0.05 to 15 parts by mass The present invention also provides curing of the above composition. It is an automobile oil seal containing objects.

The composition of the present invention has a remarkably low degree of foaming when in contact with automobile oil, particularly transmission oil. In addition, it forms a cured product that is excellent in adhesion to the engine and less deteriorated by oil.

  In the composition of the present invention, the component (A) is an organopolysiloxane that serves as a base polymer. The organopolysiloxane has at least two silanol groups or alkoxy groups per molecule, preferably at both ends of the molecule. The component (A) has a degree of polymerization of 10 or more and is preferably liquid. More preferably, the viscosity at 25 ° C. is 1,000 to 300,000 mPa · s, and particularly preferably 5,000 to 100,000 mPa · s. In the present invention, the viscosity is a value measured by a rotational viscometer. If the viscosity is too low, the physical properties of the cured product, particularly flexibility and impact resistance, tend to be insufficient. On the other hand, when the viscosity is too high, the viscosity of the composition becomes high, and workability may be reduced. The organopolysiloxane is a substantially linear diorganopolysiloxane, but may have a branched structure as long as it has rubber elasticity after curing.

Preferably, the component (A) is at least one selected from the group consisting of organopolysiloxanes represented by the following formulas (1) to (6).

HO (SiR ² ₂ O) _m H (1)

(Here, R ² is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and m is an integer of 10 or more.)

（式中、Ｒ及びＲ²は上記のとおりであり、Ｙは酸素原子または炭素原子数１〜５のアルキレン基であり、ｍは１０以上の整数、ｎは互いに独立に０又は１である。）

Wherein R and R ² are as described above, Y is an oxygen atom or an alkylene group having 1 to 5 carbon atoms, m is an integer of 10 or more, and n is 0 or 1 independently of each other. )

（式中、Ｒ、Ｒ²、Ｙ、ｍ、ｎは上記のとおりであり、Ｚは炭素原子数２〜５のアルケニル基である。）

(In the formula, R, R ² , Y, m, and n are as described above, and Z is an alkenyl group having 2 to 5 carbon atoms.)

（式中、Ｒ、Ｒ²、Ｙ、ｍ、ｎは上記のとおりであり、ｋは１〜１０の整数であり、Ｒ³は下記一般式（５）で示される加水分解性基を含む分岐鎖である。）

(In the formula, R, R ² , Y, m, and n are as described above, k is an integer of 1 to 10, and R ³ is a branch containing a hydrolyzable group represented by the following general formula (5). A chain.)

（ここで、Ｒ、Ｒ²、Ｙ、ｎは上記の通りである。）

(Here, R, R ² , Y, and n are as described above.)

（式中、Ｒ、Ｒ²、Ｒ³、Ｙ、Ｚ、ｎ、ｍは上記のとおりである。）

(In the formula, R, R ² , R ³ , Y, Z, n and m are as described above.)

  Of these, the organopolysiloxane represented by the formula (1) is more preferable. By using the organopolysiloxane in combination with at least one of the organopolysiloxanes represented by the formulas (2) to (6), a composition having higher storage stability can be obtained.

In the general formulas (2) to (6), R is an alkyl group having 1 to 4 carbon atoms, preferably a methyl group or an ethyl group, and particularly preferably a methyl group. R ² is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, particularly 1 to 6 carbon atoms. Examples of R ² include an alkyl group such as a methyl group, an ethyl group, and a propyl group; a cycloalkyl group such as a cyclohexyl group; an aryl group such as a phenyl group; and a hydrogen atom of these groups is partially substituted with a halogen atom. Group, for example, 3,3,3-trifluoropropyl group and the like. Among these, a methyl group, an ethyl group, a phenyl group, and a 3,3,3-trifluoropropyl group are preferable, a methyl group is particularly preferable, and 50 mol% or more, particularly 80 mol% or more of R is a methyl group. Is preferred. The plurality of R ² may be the same group or different groups.

  Y is an oxygen atom or an alkylene group having 1 to 5 carbon atoms. Examples of the alkylene group include a methylene group, an ethylene group, a propylene group, and a butylene group, and an ethylene group is preferable.

Z is an alkenyl group having 2 to 5 carbon atoms. As an alkenyl group, a vinyl group, an allyl group, a butenyl group, a pentenyl group etc. are mentioned, for example, Among these, a vinyl group is preferable.

(B) As the inorganic filler, surfaced or untreated fumed silica, precipitated silica, wet silica, carbon powder, talc, bentonite, calcium carbonate, zinc carbonate, magnesium carbonate, calcium oxide, zinc oxide, Examples thereof include magnesium oxide, aluminum oxide, and aluminum hydroxide. Of these, fumed silica, carbon powder, and calcium carbonate are preferable, and surface-treated calcium carbonate is particularly preferable.

(B) The compounding quantity of a component is 10-300 mass parts with respect to 100 mass parts of (A) component, Preferably, it is 20-200 mass parts. In the composition in which the amount of the filler is less than the lower limit, the rubber strength of the cured product is lowered. On the other hand, a composition containing a filler in excess of the above upper limit has low storage stability and poor dischargeability from the cartridge. Furthermore, the mechanical properties of the rubber properties of the resulting cured product are not satisfactory.

The component (C) is an alkoxysilane represented by the following general formula (7), a partial hydrolyzate thereof, or a combination thereof. Here, the “partial hydrolyzate” includes a condensate in which a part of the alkoxy group is hydrolyzed and the generated silanol group is condensed.

R ¹⁴ _-n Si (OR) _n (7)

In Formula (7), R is a methyl group or an ethyl group mutually independently. R ¹ , independently of each other, is a substituted or unsubstituted monovalent group having 1 to 20 carbon atoms, and n is an integer of 2 to 4. R ¹ is an alkyl group such as a methyl group or an ethyl group; an alkenyl group such as a vinyl group or an allyl group; an aryl group such as a phenyl group; a carbonyloxy-containing group such as an alkyloxycarbonylalkyl group; and a halogen substituent thereof. For example, a 3,3,3-trifluoropropyl group is mentioned. Examples of the component (C) include tetramethoxysilane, ethyl silicate, propyl silicate, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, methyltris (methoxyethoxy) silane, vinyltris ( Methoxyethoxy) silane, dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, vinylmethyldimethoxysilane and other general alkoxysilanes, reaction products of acrylates and alkoxymethylsilanes, such as 2-ethylhexyl acrylate and dimethoxy Examples include a reaction product with methylsilane, a reaction product with 2-ethylhexyl acrylate and trimethoxysilane, and a partial hydrolyzate of these silanes. A combination of two or more of these may be used. When it is a partial hydrolysis-condensation product, it is preferable that it is an oligomer with a polymerization degree of about 2-8.

(C) As a component, the partial hydrolysis-condensation product of methyltrimethoxysilane and the reaction product of the acrylic ester represented by a following formula, and dialkoxymethylsilane are preferable.

Ｒは上記のとおりであり、Ｒ^６は炭素原子数１〜１５の炭化水素基であり、より好ましくは２−エチルヘキシル基である。Ｒ^７は炭素数２〜４の二価炭化水素基である。Ｒ^８は炭素原子数１〜１０の炭化水素基であり、好ましくはメチル基である。

R is as described above, and R ⁶ is a hydrocarbon group having 1 to 15 carbon atoms, more preferably a 2-ethylhexyl group. R ⁷ is a divalent hydrocarbon group having 2 to 4 carbon atoms. R ⁸ is a hydrocarbon group having 1 to 10 carbon atoms, preferably a methyl group.

(C) 2 or more types of mixtures may be sufficient as a component. (C) The compounding quantity of a component is 1-30 mass parts with respect to 100 mass parts of (A) component, Preferably it is 3-15 mass parts. The composition having the component (C) less than the lower limit value may cause gelation during production or storage, and a cured product exhibiting desired elasticity may not be obtained. On the other hand, a composition containing more than the above upper limit tends to have a high shrinkage during curing and a low elasticity of the resulting cured product.

The (D) curing catalyst performs a catalytic action of a condensation reaction between the base oil of the component (A) and the component (C) in the composition of the present invention. As component (D), organic acid metal salts such as iron octoate, iron naphthenate, cobalt octoate, cobalt naphthenate, tin octoate, tin naphthenate, lead octoate and lead naphthenate, dibutyltin diacetate Alkyl tin ester compounds such as dibutyltin dilaurate and dibutyltin dioctate, metal halides such as tin halide compounds, tin orthoester compounds, tetrabutyl titanate and tetrabutylzirconate , Titanium chelate such as diisopropoxybis (acetylacetonato) titanium, diisopropoxybis (ethylacetoacetate) titanium, amines such as diethylhydroxylamine and dimethylhydroxylamine, guanidyl group-containing alkoxysilanes, etc. Is exemplified. Two or more of these may be used. Preferably, an alkyl tin ester compound, a guanidyl group-containing alkoxysilane, or a titanium chelate is used.

(D) The compounding quantity of a component is 0.01-15 mass parts with respect to 100 mass parts of (A) component, and 0.05-10 mass parts is preferable. When the amount of the component (D) is less than the above lower limit, it takes a long time to form a tack-free film when exposed to air, and the internal curability is also poor. On the other hand, a composition in which the amount of the component (D) exceeds the upper limit is extremely short in film formation time of several seconds, resulting in poor workability, and the resulting cured product tends to have low heat resistance.

(E) A silane coupling agent has the effect | action which improves the adhesiveness and chemical-resistance of the composition of this invention. Examples of the silane coupling agent include (meth) acrylic silane coupling agents, epoxy silane coupling agents, aminosilane coupling agents, mercaptosilane coupling agents, and the like. For example, γ-methacryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyltriethoxysilane, N-β- ( Aminoethyl) γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane and the like are exemplified.

  Among these, aminosilane coupling agents are preferable, and silane coupling agents represented by the following general formula (8) are particularly preferable, and the chemical resistance is remarkably improved.

式中、Ｒ、Ｒ²は上記の通りであり、Ｒ^４は炭素数１〜１０の二価の炭化水素基、Ｒ^５は芳香環を含む炭素数７〜１０の二価の炭化水素基を示し、Ｒ^５は芳香環を含む炭素数７〜１０の二価の炭化水素基、但し、ＮＨ基及びＮＨ₂基の少なくとも一方は該芳香環には結合しておらず、及びｐは１〜３、好ましくは２、３の整数である。該シランカップリング剤の詳細は、特開平５−１０５６８９号公報を参照されたい。

In the formula, R and R ² are as described above, R ⁴ is a divalent hydrocarbon group having 1 to 10 carbon atoms, and R ⁵ is a divalent hydrocarbon group having 7 to 10 carbon atoms including an aromatic ring. R ⁵ is a C 7-10 divalent hydrocarbon group containing an aromatic ring, provided that at least one of the NH group and the NH ₂ group is not bonded to the aromatic ring, and p is 1 to An integer of 3, preferably 2 or 3. For details of the silane coupling agent, refer to JP-A-5-105689.

In the formula (8), R is preferably a methyl group or an ethyl group, and R ⁴ is a methylene group, ethylene group, propylene group, tetramethylene group, hexamethylene group, octamethylene group, decamethylene group, 2-methylpropylene. An alkylene group such as a group, an arylene group such as a phenylene group, a group in which these alkylene groups and an arylene group are bonded, and the like, preferably a methylene group, an ethylene group, a propylene group, and the like, particularly preferably a propylene group It is.

R ⁵ is preferably a group in which a phenylene group and an alkylene group are bonded, and examples thereof include those represented by the following formula.
—CH ₂ —C ₆ H ₄ —
—CH ₂ —C ₆ H ₄ —CH ₂ —
—CH ₂ —C ₆ H ₄ —CH ₂ —CH ₂ —
_{-CH 2 -C 6 H 4 -CH 2} -CH 2 -CH 2 -
—CH ₂ —CH ₂ —C ₆ H ₄ —
—CH ₂ —CH ₂ —C ₆ H ₄ —CH ₂ —
_{-CH 2 -CH 2 -C 6 H 4} -CH 2 -CH 2 -
—CH ₂ —CH ₂ —CH ₂ —C ₆ H ₄ —
_{-CH 2 -CH 2 -CH 2 -C 6} H 4 -CH 2 -
Of these, —CH ₂ —C ₆ H ₄ —CH ₂ — is particularly preferred. In these formulas, the alkylene group bonded to the right side of the phenylene group (NH ₂ side in Formula (8)) (when there is no alkylene group, it becomes —NH ₂ group) is in the ortho, meta, and para positions. May be.

Examples of the silane coupling agent represented by the formula (8) include those represented by the following formula.

  (E) The quantity of a component is 0.05-15 mass parts per 100 mass parts of (A) component, Preferably it is 0.5-10 mass parts, Most preferably, it is 1-5 mass parts. When used below the lower limit, the cured product may not exhibit sufficient adhesion performance. On the other hand, when it is used in an amount exceeding the upper limit, it becomes difficult to obtain a cured product having desired rubber elasticity, which is disadvantageous economically.

In the composition of the present invention, in addition to the components (A) to (E), various additives can be blended in amounts that do not hinder the achievement of the object of the present invention. For example, fibrous fillers such as asbestos, glass fibers, carbon fibers, organic fibers; heat resistance improvers such as Bengala and cerium oxide; cold resistance improvers; dehydrating agents; rust preventives; pigments; Diluents such as diorganopolysiloxanes blocked with groups; liquid reinforcing agents such as network polysiloxanes composed of triorganosiloxy units and SiO ₂ units; and organic polyhydric alcohols such as hexamethyldisilazane, glycerin, fatty acids, Examples thereof include storage stabilizers such as fatty acid esters. Two or more of these may be used in combination.

  The room temperature curable organopolysiloxane composition of the present invention can be obtained by mixing the components (A) to (E) and various additives as necessary while blocking moisture. The obtained composition can be used as a so-called one-component room temperature curable organopolysiloxane composition which is stored in a closed container and cured into a rubbery elastic body by being exposed to moisture in the air during use.

  EXAMPLES Hereinafter, although this invention is demonstrated with reference to a synthesis example, an Example, and a comparative example, this invention is not restrict | limited to the following Example. In addition, in the following example, a part shows a mass part and a viscosity is a measured value with a rotational viscometer at 25 degreeC.

[Example 1]
Heavy calcium carbonate (trade name: MC Coat S-20, Maruo Calcium (trade name; MC Coat S-20), whose surface is treated with fatty acid on 100 parts by weight of dimethylpolysiloxane having a viscosity of 5,000 mPa · s, both ends of which are blocked with hydroxyl groups 80 parts by weight, colloidal calcium carbonate whose surface is treated with fatty acid (trade name: Shiraka Hana CC-R, manufactured by Shiraishi Calcium Co., Ltd.) 40 parts by weight, and acetylene black powder (trade name; Denka black powder) 12 parts by weight of Denki Kagaku Kogyo Co., Ltd.) was dispersed and mixed until uniform. To the resulting mixture, 5 parts by weight of a reaction product of 2-ethylhexyl acrylate and dimethoxymethylsilane (trade name; OCMS-2, manufactured by Shin-Etsu Chemical Co., Ltd.) and a partial hydrolysis condensate of methyltrimethoxysilane (Product name: KC-89E, manufactured by Shin-Etsu Chemical Co., Ltd.) 5 parts by weight and 1,1,3,3-tetramethyl-2- [3-trimethoxysilyl] propylguanidine 0.6 part by weight were added. The mixture was dispersed and mixed until uniform under reduced pressure. To the resulting mixture, 1.2 parts by weight of γ-aminopropyltriethoxysilane and 0.12 parts by weight of dioctyltin diversate were added and mixed well under reduced pressure to obtain Composition 1.

[Example 2]
Heavy calcium carbonate (trade name: MC Coat S-20, Maruo Calcium (trade name; MC Coat S-20) whose surface is treated with fatty acid on 100 parts by weight of dimethylpolysiloxane having a viscosity of 20,000 mPa · s, both ends of which are blocked with hydroxyl groups 80 parts by weight, colloidal calcium carbonate whose surface is treated with fatty acid (trade name; Shiraka Hana CC-R, manufactured by Shiraishi Calcium Co., Ltd.) 20 parts by weight, acetylene black powder (trade name; Denka black powder, 12 parts by weight of Denki Kagaku Kogyo Co., Ltd. was dispersed and mixed until uniform. To the obtained mixture, 3 parts by weight of a reaction product of 2-ethylhexyl acrylate and dimethoxymethylsilane (trade name; OCMS-2, manufactured by Shin-Etsu Chemical Co., Ltd.) and a partial hydrolyzate of methyltrimethoxysilane ( Trade name: KC-89E, manufactured by Shin-Etsu Chemical Co., Ltd.) 5 parts by weight and 1,1,3,3-tetramethyl-2- [3-trimethoxysilyl] propylguanidine 0.6 part by weight were added, Dispersion mixing was performed until uniform under reduced pressure. A compound obtained by dehydrochlorination reaction of xylylenediamine and 3-chloropropyltrimethoxysilane having a structure represented by the following formula (trade name; CF-73, manufactured by Shin-Etsu Chemical Co., Ltd.) 2.5 parts by weight and 0.12 parts by weight of dioctyltin diversate were added and mixed well under reduced pressure to obtain Composition 2.

[Example 3]
Heavy calcium carbonate (trade name; MC Coat P-20, Maruo) with 100 parts by weight of dimethylpolysiloxane having a viscosity of 20,000 mPa · s blocked at both ends of the molecular chain with a trimethoxy group and treated with a paraffinic surface. 60 parts by weight of Calcium Co., Ltd. and 15 parts by weight of acetylene black powder (trade name; Denka Black powder, manufactured by Denki Kagaku Kogyo Co., Ltd.) were dispersed and mixed until uniform. The above mixture obtained by dehydrochlorination reaction of 5 parts by weight of methyltrimethoxysilane, 2 parts by weight of diisopropoxybis (acetylacetonato) titanium, xylylenediamine and 3-chloropropyltrimethoxysilane was added to the obtained mixture. 1 part by weight of a compound (trade name: CF-73, manufactured by Shin-Etsu Chemical Co., Ltd.) was added and mixed well under reduced pressure to obtain Composition 3.

[Example 4]
Heavy calcium carbonate (trade name; MC Coat S-20, Maruo Calcium, whose surface is treated with fatty acid on 100 parts by weight of dimethylpolysiloxane having a viscosity of 20,000 mPa · s, both ends of which are blocked with trimethoxy groups. 80 parts by weight and 12 parts by weight of acetylene black powder (trade name; Denka Black powder, manufactured by Denki Kagaku Kogyo Co., Ltd.) were dispersed and mixed until uniform. To the resulting mixture, 5 parts by weight of a partial hydrolyzate of methyltrimethoxysilane (trade name; KC-89E, manufactured by Shin-Etsu Chemical Co., Ltd.), dehydrochlorination reaction of xylylenediamine and 3-chloropropyltrimethoxysilane 2.5 parts by weight of the above compound (trade name; CF-73, manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.12 parts by weight of dioctyltin diversate were added and mixed thoroughly under reduced pressure to give Composition 4 Got.

[Example 5]
Heavy calcium carbonate with 100 parts by weight of dimethylpolysiloxane having a viscosity of 20,000 mPa · s sealed with trimethoxy groups at both ends of the molecular chain via ethylene groups (trade name: MC coat) 60 parts by weight of P-20, manufactured by Maruo Calcium Co., Ltd. and 15 parts by weight of acetylene black powder (trade name; Denka Black powder, manufactured by Denki Kagaku Kogyo Co., Ltd.) were dispersed and mixed until uniform. 3 parts by weight of a partial hydrolyzate of methyltrimethoxysilane (trade name: KC-89E, manufactured by Shin-Etsu Chemical Co., Ltd.), 2 parts by weight of diisopropoxybis (acetylacetonato) titanium 1 part by weight of the above compound (trade name; CF-73, manufactured by Shin-Etsu Chemical Co., Ltd.) obtained by dehydrochlorination reaction of xylylenediamine and 3-chloropropyltrimethoxysilane was added and mixed well under reduced pressure. A composition 5 was obtained.

[Example 6]
Heavy calcium carbonate (trade name; MC Coat S) whose surface is treated with fatty acid on 100 parts by weight of dimethylpolysiloxane having a viscosity of 20,000 mPa · s, both ends of which are blocked with ethylene groups via ethylene groups -20, Maruo Calcium Co., Ltd.) 80 parts by weight and acetylene black powder (trade name; Denka Black powder, manufactured by Denki Kagaku Kogyo Co., Ltd.) 12 parts by weight were dispersed and mixed until uniform. To the resulting mixture, 5 parts by weight of a partial hydrolyzate of methyltrimethoxysilane (trade name; KC-89E, manufactured by Shin-Etsu Chemical Co., Ltd.), dehydrochlorination reaction of xylylenediamine and 3-chloropropyltrimethoxysilane 2.5 parts by weight of the above compound (trade name; CF-73, manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.12 part by weight of dioctyltin diversate were added and mixed well under reduced pressure. Obtained.

[Comparative Example 1]
In Example 1, the same procedure as in Example 1 was used except that methyltri (methylethylketoxime) silane was used instead of the reaction product of 2-ethylhexyl acrylate and dimethoxymethylsilane and the partial hydrolyzate of methyltrimethoxysilane. A comparative composition was prepared.

<Evaluation method>
The obtained composition was evaluated according to the following method. The results are shown in Table 1.
1. 0.63 g of the foamability test composition was weighed and dissolved in xylene. The resulting solution was added to and mixed with 250 ml of automatic transmission oil [trade name: Nissan genuine ATF fluid MATIC S], and the foaming property was measured according to JIS K2518. Further, after the solution was aged at 120 ° C. for 240 hours, the foamability was similarly evaluated.
2. The tack free time and slump property of the composition were measured according to JIS A 5758.
3. The rubber property value composition was poured into a 2 mm mold and cured at 23 ° C. and 50% RH for 7 days to obtain a rubber sheet having a thickness of 2 mm. The sheet was measured for rubber physical properties (referred to as “initial rubber physical properties”) in accordance with JIS K 6249.
4). Shear adhesive strength width 25 mm, length 100 mm, 1 mm thickness of two aluminum plates through the composition applied to the width 25 mm, length 10 mm, thickness 1 mm end of each plate in the length direction The two plates were bonded by shifting in the length direction so as to overlap only at 10 mm, placing a weight on the upper aluminum plate, and curing for 7 days at 23 ° C. and 50% RH. About the obtained test piece, the shear adhesive force was measured.
5). Oil resistance After immersing the rubber sheet obtained by the above method and the shear adhesion test piece in each of automatic transmission oil and continuous variable transmission oil at 150 ° C. for 10 days, the rubber properties and The adhesive force was measured. The automatic transmission oil and continuously variable transmission oil used are as follows.
Automatic transmission oil [Product name: Nissan genuine ATF fluid MATIC S]
Continuously variable transmission oil [Product name: Nissan genuine CVT fluid NS-2]

As shown in Table 1, the composition of the example containing the component (C) has significantly less foaming than the comparative example 1 (deoxime type) lacking the component, and the physical properties by being immersed in oil. The degree of deterioration is low.

The room temperature curable organopolysiloxane composition of the present invention has a significantly lower degree of foaming compared to conventional compositions even when dispersed or dissolved in an automatic transmission oil for automobiles and a continuously variable transmission oil. . The composition is particularly useful as an oil seal material for an automatic transmission having a complicated structure.

Claims (5)

(A) Diorganopolysiloxane having at least two silanol groups or alkoxy groups per molecule and having a polymerization degree of 10 or more 100 parts by mass (B) Inorganic filler 10 to 300 parts by mass (C) The following general formula ( 7) Alkoxysilane, a partial hydrolyzate thereof, or a combination thereof R ¹⁴ _-n Si (OR) _n (7)

Wherein R is independently an alkyl group having 1 to 4 carbon atoms, R ¹ is independently a substituted or unsubstituted monovalent group having 1 to 20 carbon atoms, and n is independently 1 to 30 parts by mass (D) curing catalyst 0.01 to 15 parts by mass (E) Silane coupling agent 0.05 to 15 parts by mass Room temperature curable organopolysiloxane composition. The composition according to claim 1, wherein the component (A) is at least one selected from the group consisting of organopolysiloxanes represented by the following formulas (1) to (6).

HO (SiR ² ₂ O) _m H (1)

(Here, R ² is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and m is an integer of 10 or more.)

Wherein R and R ² are as described above, Y is an oxygen atom or an alkylene group having 1 to 5 carbon atoms, m is an integer of 10 or more, and n is 0 or 1 independently of each other. )

(In the formula, R, R ² , Y, m, and n are as described above, and Z is an alkenyl group having 2 to 5 carbon atoms.)

(In the formula, R, R ² , Y, m, and n are as described above, k is an integer of 1 to 10, and R ³ is a branch containing a hydrolyzable group represented by the following general formula (5). A chain.)

(Here, R, R ² , Y, and n are as described above.)

(In the formula, R, R ² , R ³ , Y, Z, n and m are as described above.) The composition according to claim 1 or 2, wherein the component (E) is a silane compound represented by the following general formula (8) or a partial hydrolyzate thereof.

(In the formula, R and R ² are as described above, R ⁴ is a divalent hydrocarbon group having 1 to 10 carbon atoms, and R ⁵ is a divalent hydrocarbon group having 7 to 10 carbon atoms including an aromatic ring. (However, at least one of the NH group and the NH ₂ group is not bonded to the aromatic ring, and p is an integer of 1 to 3). The composition according to any one of claims 1 to 3, further comprising a component that is used in contact with transmission oil of an automobile and reacts with a substance contained in the transmission oil to act as a surfactant. object. The automobile oil seal containing the hardened | cured material of the composition which concerns on any one of Claims 1-4.