JP5902574B2 - Room temperature curable organopolysiloxane composition and automotive oil seal using the composition - Google Patents

Description

  The present invention relates to a room temperature curable organopolysiloxane composition, mainly an adhesive room temperature curable organopolysiloxane composition, and an automobile oil seal using the composition.

  Conventionally, oil-resistant gaskets and packing materials made of cork, organic rubber, asbestos, etc. have been used for the seals around automobile engines, but this has the disadvantage of complicated inventory management and work processes. Furthermore, there is a disadvantage that the sealing performance is not reliable. For this reason, the FIPG method (Formed In Place Gaskets) using room temperature curable silicone rubber has been adopted for this type of application, and has been highly evaluated in terms of workability, sealing performance, and heat resistance. .

  However, the above-mentioned materials were originally used only at locations where engine oil was sealed, but recently, long-life coolant that seals automatic transmission fluid (hereinafter abbreviated as ATF) and engine cooling. (Simply referred to as “LLC”), etc., the number of places where it is used is expanded, and the types of sealing materials are increased, engine oil grades, ATF grades, LLC grades, etc. Have been subdivided.

  In addition, the grades of these chemicals have been increasing year by year due to fuel savings and longer life. For example, engine oil, which was originally 10W-30 SD grade, has now been upgraded to SN grade. It has shifted to 0W-20, 5W-30, etc.

Among the above-mentioned sealing material grades, it is known that a technique for improving the LLC resistance performance is particularly difficult.
As a technique for improving LLC resistance, Patent Document 1 uses a method using silica treated with monoorganosilane or monoorganopolysilazane, and Patent Document 2 and Patent Document 3 use a treating agent having a softening point of 100 ° C. or higher. There has been proposed a method using colloidal calcium carbonate treated in the above manner.

  However, even if the surface treatment agents for these fillers are variously changed, the active groups on the filler surface cannot be completely treated, and therefore the LLC-resistant performance cannot be improved.

  Patent Document 4 proposes a method using a specific amount of titanium dioxide, Patent Document 5 uses a zinc oxide powder, and Patent Document 6 proposes a method using iron oxide. However, even if these fillers are used, water absorption of the polyorganosiloxane composition cannot be suppressed, so that sufficient LLC resistance cannot be obtained.

  In recent years, in Patent Document 7 and Patent Document 8, a method using an organopolysiloxane in which an organooxy group-bonded silicon atom is introduced into a terminal or a side chain via a divalent hydrocarbon group, and in Patent Document 9, A method using carbon black or MQ resin which is a crosslinking density improver has been proposed.

  Although these proposals are effective for LLC resistance, since the curing type is limited to the dealcoholization type, the initial curing is slow, and the time until engine oil can be injected after engine manufacture is increased. Therefore, the production efficiency is reduced. In addition, when these organopolysiloxanes having modified terminals are used, they are expensive because they are special, and have been avoided in recent years when cost competitiveness is severe.

  In Patent Document 10, it is proposed to use a specific amount of a partially hydrolyzed condensate of alkoxysilane as a curing agent. However, since this composition is also dealcoholized, the disadvantage of slow initial curing is improved. Not.

Japanese Patent No. 2516454 Japanese Patent No. 3440754 Japanese Patent No. 3419273 Japanese Patent No. 2671573 Japanese Patent Laid-Open No. 7-228779 JP-A-7-258550 Japanese Patent No. 3824071 Japanese Patent No. 3900267 Japanese Patent No. 4171868 JP 2007-321122 A

  As described above, in the room temperature curable organopolysiloxane composition as a sealing material for FIPG to date, all the main fluids (engine oil, ATF, LLC) used in power engines such as engines are sealed with one kind of material. No possible one was proposed. The development of a sealing material that can be applied to a plurality of fluids with a single material and has fast curing properties has been strongly desired by the industry from the viewpoint of workability and cost.

  The present invention has been made in view of the above problems, and an object thereof is to provide a room temperature curable organopolysiloxane composition that is excellent in chemical resistance against engine oil, ATF, and LLC and has fast curing properties. To do.

In order to solve the above problems, in the present invention, a room temperature curable organopolysiloxane composition,
(A) Organopolysiloxane represented by the following general formula (1) 100 parts by mass HO (SiR ¹ ₂ O) _n H (1)
(In the formula, R ¹ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and R ¹ may be the same or different groups. N is an integer of 10 or more.)
(B) 1 to 500 parts by mass of calcium carbonate (C) 0.1 to 50 parts by mass of fumed silica whose surface has been subjected to a hydrophobic treatment (D) 3 ketoxime groups represented by the following general formula (2) 1 to 30 parts by mass of R ¹ _a Si (ON = CR ² ₂ ) _4-a (2)
(In the formula, R ¹ is the same as above, and R ² is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms. A is 0 or 1.)
(E) Partial hydrolyzate of silane compound represented by the following general formula (3) 0.2 to 5.0 parts by mass R ³ _b Si (X) _4-b (3)
(In the formula, R ³ is a methyl group and / or a vinyl group, X is an alkoxy group, and b is 0 or 1.)
(F) Silane coupling agent represented by the following general formula (4) or a partial hydrolyzate thereof 0.1 to 10 parts by mass R ⁵ _b Si (OR ¹ ) _4-b (4)
(In the formula, R ¹ is the same as described above, and R ⁵ is a non-carbon group having 1 to 10 carbon atoms containing an atom selected from one or more of nitrogen atom, sulfur atom and oxygen atom other than R ³ described above. (It consists of a substituted or substituted monovalent hydrocarbon group, and b is 1 or 2.)
(G) Curing catalyst Provided is a room temperature-curable organopolysiloxane composition characterized by containing 0.001 to 10 parts by mass.

  Such a room temperature curable organopolysiloxane composition of the present invention has excellent chemical resistance and fast curability with respect to any of engine oil, ATF, and LLC.

  Moreover, it is preferable that the specific gravity in 25 degreeC of the said (E) component exists in the range of 1.04-1.25.

  Thus, if the specific gravity at 25 ° C. of the component (E) is within the above range, sufficient fast curability and chemical resistance can be imparted, and a composition having the desired rubber elasticity can be obtained. .

  Moreover, it is preferable that the hydrolyzable group of the said (E) component is a methoxy group.

  Thus, when the hydrolyzable group of the component (E) is a methoxy group, the room temperature curable organopolysiloxane composition can be quickly introduced as a crosslinking point when the room temperature curable organopolysiloxane composition is crosslinked. Chemical resistance can be imparted.

Moreover, it is preferable that the silane coupling agent of the said (F) component contains the at least 1 sort (s) of silane coupling agent chosen from following General formula (5)-(8).
(R ¹ O) _3-c R ¹ _c SiR ⁶ NH ₂ (5)
_{^{(R 1 O) 3-c}} R 1 c SiR 6 NHC 2 H 4 NH 2 (6)
(R ¹ O) _3-c R ¹ _c SiR ⁶ NHC ₂ H ₄ NHR ⁶ COOR ⁶ SiR ¹ _c (OR ¹ ) _3-c (7)
(R ¹ O) _3-c R ¹ _c SiR ⁶ NHR ⁶ NHR ⁶ SiR ¹ _c (OR ¹ ) _3-c (8)
(In the formula, R ¹ is the same as above, R ⁶ is an unsubstituted or substituted divalent hydrocarbon group having 1 to 10 carbon atoms, and R ⁶ may be the same or different from each other.) Is an integer selected from 0, 1, and 2.)

  When the silane coupling agent as the component (F) contains such a silane coupling agent, the composition can exhibit good adhesiveness.

  The present invention also provides an automobile oil seal using the room temperature curable organopolysiloxane composition.

  Since the automobile oil seal of the present invention is excellent in all of engine oil resistance, ATF resistance, and LLC resistance, it effectively acts as a sealing material for power engines such as engines. Moreover, since it also has quick curability, improvement in workability can be expected.

  As described above, according to the room temperature curable organopolysiloxane composition of the present invention, it is cheaper than the conventional composition and has excellent chemical resistance (particularly engine oil resistance, ATF resistance and LLC resistance). In addition, a room temperature-curable organopolysiloxane composition excellent in initial curability and adhesive temporal stability and storage stability exhibited at the beginning of production can be obtained. The composition of the present invention can be expected to be applied to industries that require chemical resistance and fast curability, and is particularly effective for automotive applications.

Hereinafter, the present invention will be described in detail.
As described above, it has been desired to develop a room temperature curable organopolysiloxane composition that is excellent in chemical resistance against any of engine oil, ATF, and LLC with one kind of material and has fast curing properties.

  As a result of intensive studies to achieve the above object, the present inventors have added a partial hydrolyzate of a specific alkoxysilane to a deoxime-type room temperature curable organopolysiloxane composition, so that an oxime group and It was found that a part of the alkoxy group in the partial hydrolyzate of alkoxysilane was replaced with an oxime group by transesterification, and the initial curability was dramatically improved. In addition, the partial hydrolyzate of a specific alkoxysilane is quickly introduced into the crosslink to improve the crosslink density, and by adding calcium carbonate and fumed silica whose surface is hydrophobized, engine oil is added. The present invention was completed by finding that a room temperature-curable organopolysiloxane composition excellent in chemical resistance to ATF, ATF, and LLC can be obtained.

That is, the room temperature curable organopolysiloxane composition of the present invention is:
(A) Organopolysiloxane represented by the following general formula (1) 100 parts by mass HO (SiR ¹ ₂ O) _n H (1)
(In the formula, R ¹ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and R ¹ may be the same or different groups. N is an integer of 10 or more.)
(B) 1 to 500 parts by mass of calcium carbonate (C) 0.1 to 50 parts by mass of fumed silica whose surface has been subjected to a hydrophobic treatment (D) 3 ketoxime groups represented by the following general formula (2) 1 to 30 parts by mass of R ¹ _a Si (ON = CR ² ₂ ) _4-a (2)
(In the formula, R ¹ is the same as above, and R ² is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms. A is 0 or 1.)
(E) Partial hydrolyzate of silane compound represented by the following general formula (3) 0.2 to 5.0 parts by mass R ³ _b Si (X) _4-b (3)
(In the formula, R ³ is a methyl group and / or a vinyl group, X is an alkoxy group, and b is 0 or 1.)
(F) Silane coupling agent represented by the following general formula (4), or a partial hydrolyzate thereof 0.1 to 10 parts by mass R ⁵ _b Si (OR ¹ ) _4-b (4)
(In the formula, R ¹ is the same as described above, and R ⁵ is a non-carbon group having 1 to 10 carbon atoms containing an atom selected from one or more of nitrogen atom, sulfur atom and oxygen atom other than R ³ described above. (It consists of a substituted or substituted monovalent hydrocarbon group, and b is 1 or 2.)
(G) Curing catalyst It is characterized by containing 0.001-10 mass parts.

Hereinafter, the present invention will be described in more detail.
[(A) component]
The component (A) is an organopolysiloxane represented by the following general formula (1).
HO (SiR ¹ ₂ O) _n H (1)
In the above formula (1), R ¹ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, for example, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, and an octyl group. A cycloalkyl group such as a cyclohexyl group; an alkenyl group such as a vinyl group, an allyl group, a propenyl group, a butenyl group, and a hexenyl group; an aryl group such as a phenyl group and a tolyl group; an aralkyl group such as a benzyl group and a phenylethyl group; A group in which the hydrogen atom of these groups is partially substituted with a halogen atom such as chlorine, fluorine or bromine, such as a trifluoropropyl group, is preferably a methyl group or a phenyl group, and particularly preferably a methyl group.

R ¹ may be the same or different from each other. N in the formula (1) is an integer of 10 or more, and the viscosity of this organopolysiloxane at 25 ° C. is in the range of 1,000 to 500,000 mPa · s, particularly 5,000 to 100,000 mPa · s. It is preferable to be in the range. In the present invention, the viscosity is a value measured with a rotational viscometer.

[Component (B)]
Calcium carbonate as component (B) refers to a reinforcing and non-reinforcing filler for imparting good engine oil resistance and ATF resistance to the composition, and also imparting rubber physical properties. As the calcium carbonate as the component (B), calcium carbonate in any surface state can be used regardless of whether it is surface-treated or untreated. Examples of calcium carbonate that is preferably used include heavy calcium carbonate and colloidal calcium carbonate.

  (B) The compounding quantity of a component is used in the range of 1-500 mass parts with respect to 100 mass parts of (A) component, Preferably, it is used in the range of 10-300 mass parts. If it is less than 1 part by mass, sufficient chemical resistance and rubber strength cannot be obtained, so that there is a problem that it is not suitable for the intended use. If it exceeds 500 parts by mass, the mixing property of the composition is deteriorated and the rubber properties obtained are obtained. The mechanical properties of this will also deteriorate.

[Component (C)]
Next, the fumed silica whose surface, which is the component (C), has been hydrophobized, imparts good thixotropy to the composition and also provides reinforcing properties for imparting rubber properties with good LLC resistance. Refers to reinforcing filler. The surface treatment agent for the (C) component fumed silica is preferably selected from chlorosilane, silazane, and siloxane. Among them, the fumed silica that has been hydrophobized using chlorosilane and silazane as the surface treatment agent is used. It is particularly preferred.

The specific surface area of the fumed silica whose surface is hydrophobized used are preferably those in the range of 50 to 300 m ² / g, more be used within the scope of 100 to 200 m ² / g among them preferable.

  (C) The compounding quantity of a component is 0.1-50 mass parts with respect to 100 mass parts of (A) component, Preferably, it is used in 0.5-20 mass parts. If the amount is less than 0.1 parts by mass, sufficient thixotropy / reinforcing properties cannot be obtained, and the rubber strength after LLC resistance is deteriorated. If the amount exceeds 50 parts by mass, the mixability of the composition deteriorates. In addition, the mechanical properties of the rubber properties obtained are also reduced.

[(D) component]
The silane compound having 3 or more ketoxime groups represented by the following general formula (2), which is the component (D), imparts good storage stability to the composition under hermetic conditions, and after opening Is a component that acts as a curing agent to react with moisture in the air and make it rubber.
R ¹ _a Si (ON = CR ² ₂ ) _4-a (2)
(In the formula, R ¹ is the same as above, and R ² is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms. A is 0 or 1.)

Here, what is selected as R ¹ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, among which an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms is preferable, A methyl group, a vinyl group, and a phenyl group are more preferable. R ² is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms. Among them, an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms is preferable, and a methyl group or an ethyl group is particularly preferable. , A propyl group, a butyl group, and an isobutyl group are more preferable. R ¹ and R ² may be the same or different from each other.

  Specific examples of the hydrolyzable silane compound (D) include methyltris (dimethylketoxime) silane, methyltris (methylethylketoxime) silane, methyltris (methylisobutylketoxime) silane, methyltris (methylpropylketoxime) silane, methyltris (Methylbutylketoxime) silane, vinyltris (methylethylketoxime) silane, vinyltris (dimethylketoxime) silane, vinyltris (methylisobutylketoxime) silane, vinyltris (methylpropylketoxime) silane, vinyltris (methylbutylketoxime) silane, etc. The ketoxime silane shown by the formula (2) is exemplified, and these can be used alone or in combination of two or more.

  The silane compound as the component (D) is used in an amount of 1 to 30 parts by weight, preferably 3 to 20 parts by weight, based on 100 parts by weight of the organopolysiloxane of the component (A). If the amount is less than 30%, sufficient crosslinking cannot be obtained, and the composition does not have the desired rubber elasticity. If the amount exceeds 30 parts by mass, the mechanical properties of the obtained rubber properties also deteriorate.

[(E) component]
The partial hydrolyzate of the silane compound represented by the following general formula (3), which is the component (E), improves the crosslink density of the composition and has good chemical resistance (particularly engine oil resistance and ATF resistance). , LLC resistance) is an essential component.
R ³ _b Si (X) _4-b (3)
(In the formula, R ³ is a methyl group and / or a vinyl group, X is an alkoxy group, and b is 0 or 1.)

  The hydrolyzable group of the component (E) is an alkoxy group, and among them, a methoxy group is more preferable. This is because the ketoxime group, acetoxy group, and isopropenoxy group are too hydrolyzable with moisture, causing gelation and viscosity increase during the production of this composition. In addition, a part of the alkoxy group slowly undergoes a transesterification reaction with the oxime group of the component (D), and the provision of fast curability is achieved by the replacement of the alkoxy group and the oxime group.

  In addition, when the alkoxy group is a methoxy group, when the room temperature curable organopolysiloxane composition is crosslinked, the component (E) can be quickly introduced as a crosslinking point, which can provide excellent chemical resistance. .

  The component (E) preferably has a specific gravity at 25 ° C. in the range of 1.04 to 1.25, more preferably in the range of 1.06 to 1.10. When the specific gravity at 25 ° C. is 1.04 or more, sufficient fast curability and chemical resistance can be imparted, and the composition having the desired rubber elasticity can be obtained. In addition, if the specific gravity at 25 ° C. is 1.25 or less, the crosslinking point is appropriate, and therefore, there is no fear that the mechanical properties of the obtained rubber properties are deteriorated.

[(F) component]
The component (F) is a silane coupling agent represented by the following general formula (4) or a partial hydrolyzate thereof, and is an essential component for causing the composition to exhibit good adhesiveness.
R ⁵ _b Si (OR ¹ ) _4-b (4)
(In the formula, R ¹ is the same as described above, and R ⁵ is a non-carbon group having 1 to 10 carbon atoms containing an atom selected from one or more of nitrogen atom, sulfur atom and oxygen atom other than R ³ described above. (It consists of a substituted or substituted monovalent hydrocarbon group, and b is 1 or 2.)

As specific examples of the hydrolyzable silane coupling agent of component (F), a large number of silane coupling agents can be exemplified, among which at least one of a nitrogen atom, a sulfur atom, or an oxygen atom. It is preferably an unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms containing an atom selected from one or more, and among them, a silane coupling agent represented by the following general formulas (5) to (8) is used. Then, favorable adhesiveness can be obtained. Moreover, these are not limited to 1 type, You may use the 2 types simultaneously.
(R ¹ O) _3-c R ¹ _c SiR ⁶ NH ₂ (5)
_{^{(R 1 O) 3-c}} R 1 c SiR 6 NHC 2 H 4 NH 2 (6)
(R ¹ O) _3-c R ¹ _c SiR ⁶ NHC ₂ H ₄ NHR ⁶ COOR ⁶ SiR ¹ _c (OR ¹ ) _3-c (7)
(R ¹ O) _3-c R ¹ _c SiR ⁶ NHR ⁶ NHR ⁶ SiR ¹ _c (OR ¹ ) _3-c (8)
(In the formula, R ¹ is the same as above, R ⁶ is an unsubstituted or substituted divalent hydrocarbon group having 1 to 10 carbon atoms, and R ⁶ may be the same or different from each other.) Is an integer selected from 0, 1, and 2.)

  The component (F) silane coupling agent is used in an amount of 0.1 to 10 parts by weight, preferably 0.3 to 5 parts by weight, based on 100 parts by weight of the organopolysiloxane (A). It is. Adhesiveness expected to be less than 0.1 parts by mass is not obtained, and if the amount exceeds 10 parts by mass, the resulting rubber is inferior in mechanical properties, chemical resistance is reduced, and cost is also reduced. Disadvantageous.

[(G) component]
The curing catalyst (G) is used to promote the hydrolysis reaction between the present composition and moisture in the air, and is generally called a curing catalyst. The same components as those used in the silicone resin composition that is cured in the presence of moisture, which are generally well known, can be used.

  Examples of the component (G) include tin-based catalysts, bismuth-based catalysts, and titanium-based catalysts, and it is more preferable to use tin-based catalysts and bismuth-based catalysts. Specific examples of tin-based catalysts include tin naphthenate, tin caprylate, dibutyltin diacetate, dibutyltin dioctate, dibutyltin dilaurate, dibutyltin diacetate, diphenyltin diacetate, dibutyltin oxide, dibutyltin dimethoxide, dibutylbis (triethoxysiloxy) ) Tin, dibutyltin benzyl malate and the like can be mentioned, and the bismuth catalyst is preferably bismuth tris (2-ethylhexanoate) or bismuth tris (neodecanoate).

  Specific examples of titanium-based catalysts include titanic acid such as tetraisopropoxy titanium, tetra-n-butoxy titanium, tetrabis (2-ethylhexoxy) titanium, dipropoxy bis (acetylacetona) titanium, titanium isopropoxy octylene glycol, and the like. Examples include esters and titanium chelate compounds.

  The amount of these curing catalysts used may be a very small amount of catalyst, and is in the range of 0.001 to 10 parts by mass, preferably 0.01 to 1 part by mass with respect to 100 parts by mass of the organopolysiloxane of component (A). It is what is used. When the amount is less than 0.001 part by mass, good curability cannot be obtained, and therefore, there is a problem that, for example, the time is extended before injecting engine oil at the time of manufacturing an automobile or the like. On the other hand, if the amount exceeds 10 parts by mass, the curability of the composition is too fast, so that the allowable time for adhering the adherend after application of the composition is shortened, or the mechanical properties of the resulting rubber are reduced. To do.

[Other additives]
In addition to the above components, generally known additives may be used in the present invention. Additives include polyethers as thixotropic agents, silicone oils as plasticizers, isoparaffins, etc., if necessary, colorants such as pigments, dyes, fluorescent brighteners, fungicides, antibacterial agents , Bioactive additives such as marine organism repellent, phenyl silicone oil as bleed oil, fluorosilicone oil, surface modifiers such as organic liquid incompatible with silicone, toluene, xylene, solvent volatile oil, cyclohexane, methyl Solvents such as cyclohexane and low boiling isoparaffin are also added.

  The room temperature-curable organopolysiloxane composition of the present invention can be obtained by mixing the components (A) to (G) and various additives as necessary while blocking moisture. The obtained composition is stored as it is in a sealed container, and is cured into a rubber-like elastic body by being exposed to moisture in the air at the time of use. Application to and use in a so-called one-packaging room temperature curable organopolysiloxane composition It can be used as a so-called two-packaging room temperature curable organopolysiloxane composition which is sometimes cured into a rubbery elastic body by mixing with other components. In addition, the composition obtained by this invention can anticipate the application to the industry where initial curability is calculated | required. Among them, it is particularly effective for automotive oil seal applications that require chemical resistance and rapid curability.

EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not restrict | limited to the following Example.
[Example 1]
(A) To 100 parts by mass of polydimethylsiloxane whose end at 25 ° C. has a viscosity of 50,000 mPa · s blocked with a silanol group, (B) heavy calcium carbonate with no surface treatment (trade name; Whiteon SSB, Shiroishi 100 parts by mass of Calcium Co., Ltd. and (C) 5 parts by mass of fumed silica whose surface was treated with dimethyldichlorosilane were added and mixed with a mixer, and then (D) 9 parts by mass of vinyltris (methylethylketoxime) silane And (G) 0.4 parts by mass of dibutyltin bis (benzyl malate) and thoroughly mixing under reduced pressure, and then (E) hydrolyzing mainly tetramer and pentamer of methyltrimethoxysilane. Add 1 part by weight of the decomposition mixture (specific gravity; 1.08) and 1.2 parts by weight of (F) 3-aminopropyltriethoxysilane, and mix thoroughly under reduced pressure. 1 was obtained.

[Example 2]
(A) To 100 parts by mass of polydimethylsiloxane whose end at 25 ° C. has a viscosity of 50,000 mPa · s blocked with a silanol group, (B) heavy calcium carbonate with no surface treatment (trade name; Whiteon SSB, Shiroishi 100 parts by mass of Calcium Co., Ltd. and (C) 5 parts by mass of fumed silica whose surface was treated with dimethyldichlorosilane were added and mixed with a mixer, and then (D) 9 parts by mass of vinyltris (methylethylketoxime) silane And (G) 0.4 parts by weight of dibutyltin bis (benzyl malate), and after complete mixing under reduced pressure, (E) a hydrolysis mixture (specific gravity) mainly composed of a tetramer of vinyltrimethoxysilane 1.10) and 1 part by weight of (F) 3-aminopropyltriethoxysilane 1.2 parts, and thoroughly mixed under reduced pressure to obtain Sample 2 .

[Example 3]
(A) To 100 parts by mass of polydimethylsiloxane whose end at 25 ° C. has a viscosity of 50,000 mPa · s blocked with a silanol group, (B) heavy calcium carbonate with no surface treatment (trade name; Whiteon SSB, Shiroishi 100 parts by mass of Calcium Co., Ltd. and (C) 5 parts by mass of fumed silica whose surface was treated with dimethyldichlorosilane were added and mixed with a mixer, and then (D) 9 parts by mass of vinyltris (methylethylketoxime) silane And (G) 0.4 parts by mass of dibutyltin bis (benzyl malate), and after complete mixing under reduced pressure, (E) a hydrolysis mixture mainly composed of tetramethoxysilane tetramer (specific gravity; 1.20) and 1 part by mass of (F) 3-aminopropyltriethoxysilane (1.2 part by mass) were added and mixed under reduced pressure to obtain Sample 3.

[Example 4]
(A) Heavy calcium carbonate having a viscosity of 50,000 mPa · s at 25 ° C. and 100 parts by mass of polydimethylsiloxane whose ends are blocked with silanol groups, and (B) a surface treated with fatty acid (trade name; MC coat (S-20, manufactured by Maruo Calcium Co., Ltd.) 100 parts by mass and (C) 5 parts by mass of fumed silica whose surface was treated with dimethyldichlorosilane were added and mixed with a mixer, and then (D) vinyl tris (methyl ethyl ketoxime). ) After adding 9 parts by mass of silane and 0.4 part by mass of (G) dibutyltin bis (benzyl malate) and thoroughly mixing under reduced pressure, (E) tetramer and pentamer of methyltrimethoxysilane Add 1 part by weight of hydrolyzed mixture (specific gravity; 1.08) as the main component and 1.2 parts by weight of (F) 3-aminopropyltriethoxysilane and mix thoroughly under reduced pressure , To obtain a sample 4.

[Example 5]
(A) Colloidal calcium carbonate having a viscosity of 50,000 mPa · s at 25 ° C. and having a terminal end blocked with a silanol group, and (B) a surface treated with a fatty acid (trade name; Hakusen CC) -R, 100 parts by mass of Shiraishi Calcium Co., Ltd.) and (C) 5 parts by mass of fumed silica whose surface was treated with dimethyldichlorosilane were added and mixed with a mixer, and then (D) vinyl tris (methyl ethyl ketoxime) After adding 9 parts by weight of silane and 0.4 parts by weight of (G) dibutyltin bis (benzyl malate) and thoroughly mixing under reduced pressure, (E) tetramer and pentamer of methyltrimethoxysilane are mainly composed 1 part by weight of the resulting hydrolyzed mixture (specific gravity: 1.08) and 1.2 parts by weight of (F) 3-aminopropyltriethoxysilane were added and mixed thoroughly under reduced pressure. To obtain a sample 5.

[Example 6]
(A) To 100 parts by mass of polydimethylsiloxane whose end at 25 ° C. has a viscosity of 50,000 mPa · s blocked with a silanol group, (B) heavy calcium carbonate with no surface treatment (trade name; Whiteon SSB, Shiroishi 100 parts by mass of Calcium Co., Ltd. and (C) 5 parts by mass of fumed silica whose surface was treated with dimethyldichlorosilane were added and mixed with a mixer, and then (D) 9 parts by mass of vinyltris (methylethylketoxime) silane And (G) 0.4 parts by mass of dibutyltin bis (benzyl malate) and thoroughly mixing under reduced pressure, and then (E) hydrolyzing mainly tetramer and pentamer of methyltrimethoxysilane. Add 1 part by weight of the decomposition mixture (specific gravity; 1.08) and 1.2 parts by weight of (F) N-2- (aminoethyl) -3-aminopropyltrimethoxysilane. Thoroughly mixed under to obtain a sample 6.

[Comparative Example 1]
A sample 7 was obtained in the same manner as in Example 1 except that the hydrolysis mixture mainly composed of the tetramer and pentamer of methyltrimethoxysilane as the component (E) was removed.

[Comparative Example 2]
In Example 1, instead of the hydrolysis mixture mainly comprising tetramer and pentamer of methyltrimethoxysilane as the component (E), it consists of Me ₃ SiO _1/2 units and SiO _4/2 units, and SiO ₂ An octamethylcyclotetrasiloxane solution of a branched organopolysiloxane having a molar ratio of Me ₃ SiO _1/2 units to _4/2 units of 0.90 and containing 0.03 mol / 100 g of hydroxysilyl groups (purity; Sample 8 was prepared under the same conditions except that 5 parts by mass of 50%) was used.

[Comparative Example 3]
In Example 1, 1 part by weight of methyltrimethoxysilane (specific gravity: 0.95) was used instead of the hydrolysis mixture mainly composed of tetramer and pentamer of methyltrimethoxysilane as the component (E). Were prepared under the same conditions to obtain Sample 9.

[Comparative Example 4]
A sample 10 was obtained in the same manner as in Example 1 except that the calcium carbonate as the component (B) was removed.

[Comparative Example 5]
A sample 11 was obtained in the same manner as in Example 1 except that the surface of the component (C) was removed except for the fumed silica treated with dimethyldichlorosilane.

The compounding amounts of Examples 1 to 6 are shown in Table 1 below, and the compounding amounts of Comparative Examples 1 to 5 are shown in Table 2.

[Test method]
The room temperature curable organopolysiloxane composition (silicone rubber composition) of Samples 1 to 11 obtained in the above Examples and Comparative Examples was poured into a 2 mm mold and cured at 23 ° C. and 50% RH for 7 days to 2 mm. A thick rubber sheet was obtained. The tack-free time (touch drying time) and the slump property were measured according to the method specified in JIS A 5758, and the rubber physical properties were measured from a 2 mm thick sheet according to JIS K 6249.

Further, from this composition, a shear adhesion test body having an adhesion area of 2.5 mm ² and an adhesion thickness of 1 mm was prepared using an adherend having a width of 25 mm and a length of 100 mm, and was cured at 23 ° C. and 50% RH for 7 days. The shear adhesion was confirmed by measurement.

  In the curing rate test method, a glass petri dish having an inner diameter of 10 mm was filled with the sample, and the cured thickness was measured from the portion exposed to air after 23 ° C. and 50% RH × 1 day.

  In the storage deterioration test, the obtained composition (samples 1 to 10) is left in an uncured state at 70 ° C. for 7 days under sealed conditions, and then the same test as in the initial stage of production is performed to confirm performance deterioration. Went.

  The initial curability test method was a pressure test using a pressure vessel similar to the pressure test flange pressure vessel defined in JIS K 6820 as a test apparatus. The pressure vessel comprises an upper vessel having an upper flange having an inner diameter of 58 mm, an outer diameter of 80 mm, and a height of 10 mm, and a lower vessel having a lower flange of the same size as the upper flange, and the inner side of the seal surface of the lower flange An annular cutout having a width of 3 mm and a depth of 3 mm is provided along the circumference of the edge. The sealing surface of the lower flange was washed with toluene. Then, this composition was apply | coated and it apply | coated to the center part of the lower seal surface in the shape of a bead. Immediately after application, the upper container was placed on the lower container so that the sealing surfaces of the upper flange and the lower flange were in contact with each other, and a 20.50 mm iron spacer was installed and four fastening bolts were assembled. The spacer causes a gap of 0.5 mm between the seal surfaces, which is a so-called accelerated test that makes the pressure test more severe. After curing at 23 ° C. and 50% RH for 30 minutes, a gas was inserted from the upper pressure port, and the gas pressure that the sealant could withstand was regarded as the seal strength (initial sealability). .

  Further, the obtained rubber sheet was immersed in a 50 wt% aqueous solution of engine oil, ATF, and LLC in order to confirm the chemical resistance performance, the engine oil resistance was 120 ° C. for 7 days, and the ATF resistance and LLC resistance were 100. Deteriorated at ℃ for 7 days, conducted chemical resistance confirmation test, and judged that the rate of change in aluminum shear adhesive strength within ± 50% after chemical resistance test, which is the cause of oil leakage, was acceptable . The results of Examples 1 to 6 are shown in Table 3 below, and the results of Comparative Examples 1 to 5 are shown in Table 4.

  From the results of Examples and Comparative Examples, the room temperature curable organopolysiloxane composition of the present invention has chemical resistance and initial seal having all of engine oil resistance, ATF resistance, and LLC resistance compared to Comparative Examples. It was shown that the composition was excellent in properties.

  As described above, according to the room temperature curable organopolysiloxane composition of the present invention, it is cheaper than the conventional composition and excellent in chemical resistance (particularly engine oil resistance, ATF resistance and LLC resistance), In addition, it is possible to obtain a room temperature-curable organopolysiloxane composition having excellent initial curability and adhesive temporal stability and storage stability that are exhibited at the beginning of production. In addition, the composition of the present invention is particularly effective for automobile applications because it has excellent chemical resistance and fast curability.

The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

Claims (5)

A room temperature curable organopolysiloxane composition comprising:
(A) Organopolysiloxane represented by the following general formula (1) 100 parts by mass HO (SiR ¹ ₂ O) _n H (1)
(In the formula, R ¹ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and R ¹ may be the same or different groups. N is an integer of 10 or more.)
(B) 1 to 500 parts by mass of calcium carbonate (C) 0.1 to 50 parts by mass of fumed silica whose surface has been subjected to a hydrophobic treatment (D) 3 ketoxime groups represented by the following general formula (2) 1 to 30 parts by mass of R ¹ _a Si (ON = CR ² ₂ ) _4-a (2)
(In the formula, R ¹ is the same as above, and R ² is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms. A is 0 or 1.)
(E) Partial hydrolyzate of silane compound represented by the following general formula (3) 0.2 to 5.0 parts by mass R ³ _b Si (X) _4-b (3)
(In the formula, R ³ is a methyl group and / or a vinyl group, X is an alkoxy group, and b is 0 or 1.)
(F) Silane coupling agent represented by the following general formula (4) or a partial hydrolyzate thereof 0.1 to 10 parts by mass R ⁵ _b Si (OR ¹ ) _4-b (4)
(In the formula, R ¹ is the same as described above, and R ⁵ is a non-carbon group having 1 to 10 carbon atoms containing an atom selected from one or more of nitrogen atom, sulfur atom and oxygen atom other than R ³ described above. (It consists of a substituted or substituted monovalent hydrocarbon group, and b is 1 or 2.)
(G) Curing catalyst A room temperature-curable organopolysiloxane composition characterized by containing 0.001 to 10 parts by mass.   2. The room temperature-curable organopolysiloxane composition according to claim 1, wherein the specific gravity at 25 ° C. of the component (E) is in the range of 1.04 to 1.25. The room temperature-curable organopolysiloxane composition according to claim 1 or 2, wherein the alkoxy group of the component (E) is a methoxy group. Any one of claims 1 to 3, characterized in that it contains at least one silane coupling agent selected from the (F) component of the silane coupling agent is represented by the following general formula (5) to (8) 2. The room temperature curable organopolysiloxane composition according to item 1.
(R ¹ O) _3-c R ¹ _c SiR ⁶ NH ₂ (5)
_{^{(R 1 O) 3-c}} R 1 c SiR 6 NHC 2 H 4 NH 2 (6)
(R ¹ O) _3-c R ¹ _c SiR ⁶ NHC ₂ H ₄ NHR ⁶ COOR ⁶ SiR ¹ _c (OR ¹ ) _3-c (7)
(R ¹ O) _3-c R ¹ _c SiR ⁶ NHR ⁶ NHR ⁶ SiR ¹ _c (OR ¹ ) _3-c (8)
(In the formula, R ¹ is the same as above, R ⁶ is an unsubstituted or substituted divalent hydrocarbon group having 1 to 10 carbon atoms, and R ⁶ may be the same or different from each other.) Is an integer selected from 0, 1, and 2.)   An automobile oil seal using the room temperature-curable organopolysiloxane composition according to any one of claims 1 to 4.