JPH0655933B2 - Self-adhesive silicone rubber composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a self-adhesive silicone rubber composition, and particularly to a self-adhesive silicone rubber composition which has good adhesiveness to a metal and can be easily adhered. -Related silicone rubber composition.

[Conventional technology]

Silicone rubber is used in various applications by taking advantage of its excellent properties. This silicone rubber is also used in the form of a composite formed by adhering to a metal. In the production of this composite, the surface of the metal is treated with a primer as a pretreatment for adhesion in order to firmly bond the silicone rubber and the metal.

As the primer, a composition comprising an alkoxysilane having an unsaturated bond, a hydrolyzed condensate thereof, or a cohydrolyzed siloxane, and a titanate ester and a metal salt of an organic fatty acid (Japanese Patent Publication Nos. 62-17622 and 62-62).
-17623); an alkoxysilane having an unsaturated bond or a hydrolyzed condensate or cohydrolyzed siloxane thereof, a titanate ester, a metal salt of an organic fatty acid, and
Composition comprising an Si-H group-containing organosilicon compound (Japanese Patent Publication No. 61-2107); a rubber-like composition comprising a vinyl group-containing organopolysiloxane, a polysiloxane resin, an alkoxysilane, an organic peroxide and a titanate ester. A composition (Japanese Patent Publication No. 56-39817) and the like have been proposed.

[Problems to be Solved by the Invention]

However, in the adhesion between the silicone rubber and the metal performed using these conventional primers, after the primer is applied to the adherend, the steps of air drying and baking are essential to volatilize the solvent and solidify the primer. There is a problem that the adhesion work becomes complicated. Further, the conventional primer has a drawback in that it contains a hydrolysis-condensation product, a catalyst, or a solvent, which causes a problem in terms of safety in manufacturing work.

Therefore, the object of the present invention is to have a good adhesiveness with a metal, the adhesion work can be easily carried out, and since there is no hydrolysis-condensation product or a catalyst or solvent, there is a problem in terms of the safety of the production work. It is to provide a self-adhesive silicone rubber composition that does not occur.

[Means for Solving the Problems]

In order to solve the above-mentioned problems, the present invention provides (a-1) 100 parts by weight of diorganopolysiloxane having a degree of polymerization of 3,000 to 30,000 (a-2) 10 to 300 parts by weight of finely divided silica filler (a-3 ) 0.1 to 5 parts by weight of organic peroxide and (B) general composition formula (I): [Wherein, R ¹ is a vinyl group, R ² is a substituted or unsubstituted monovalent hydrocarbon group, a is a number of 1 <a <4, and b is 0 ≦ b <
The degree of polymerization is 1 to 1000, and the total amount of the components (a-1) to (a-3) is 0.1 per 100 parts by weight. The present invention provides a self-adhesive silicone rubber composition containing 10 to 10 parts by weight.

That is, the present invention relates to an organic peroxide-curable thermosetting silicone rubber compound (hereinafter, referred to as “component (A)”) comprising the components (a-1) to (a-3), and (B) It is a blend of an organopolysiloxane having a low degree of polymerization as a component.

Examples of the diorganopolysiloxane of the component (a-1) in the organic peroxide-curable thermosetting silicone rubber compound of the component (A) include compounds represented by the formula: [Wherein R ³ is a methyl group, an ethyl group, a propyl group,
Alkyl group such as butyl group, alkenyl group such as vinyl group, allyl group and butenyl group; aryl group such as phenyl group and tolyl group; or some or all of hydrogen atoms bonded to carbon atoms of these groups are halogen atoms , A chloromethyl group substituted with a cyano group, a chloropropyl group, 3,
A same or different unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, selected from 3,3-trifluoropropyl group, 2-cyanoethyl group, etc. Yes, c is a number from 1.95 to 2.05. ] The thing represented by is mentioned. In the diorganopolysiloxane, 98% or more of R ^{3 in} the above formula is an alkyl group having 1 to 4 carbon atoms, especially a methyl group, and other R ³ is a vinyl group, a phenyl group, a trifluoro group. Those containing a propyl group are typical. Further, the molecular structure is preferably linear, but the molecule may partially contain a branched chain. The degree of polymerization is 3,000 to 30,000,
From the viewpoint of workability, those of 4,000 to 10,000 are preferable.

In addition, the silicone rubber compound of component (A)
The fine powder silica filler as the component (a-2) is added for the purpose of reinforcing, thickening, improving processability, increasing the amount of the silicone rubber, and includes fumed silica, wet silica, and a surface. Examples include hydrophobized fumed silica, wet silica, fine quartz powder, diatomaceous earth, etc., which contain some other form of filler, such as calcium silicate, calcium carbonate, carbon black, glass fiber, etc. However, they may have a specific surface area of 1 m ² / g or more, preferably 50 m ² / g or more.

If the blending amount of this product is too small, the desired reinforcing property cannot be obtained and the workability becomes insufficient. On the other hand, if the amount is too large, processing characteristics such as mold flowability and dischargeability are extremely deteriorated. The component (a-1) is used in an amount of 10 to 300 parts by weight, particularly 25 to 200 parts by weight, per 100 parts by weight of the diorganopolysiloxane.

Examples of the organic peroxide as the component (a-3) in the silicone rubber compound as the component (A) include t-butyl peroxide, dicumyl peroxide, benzoyl peroxide, monochlorobenzoyl peroxide, p-methylbenzoyl peroxide. , 2,4-dichlorobenzoyl peroxide, t-butyl perbenzoate, 2,5
-Bis- (t-butylperoxy) -2,5-dimethylhexane, 2,5-bis- (t-butylperoxy) -2,5-dimethylhexyne; dimyristylperoxycarbonate, dicyclododecylper Dicarbonates such as oxydicarbonates; t-butyl monoperoxycarbonates, the following formula: (However, in the formula, R ⁴ is a monovalent hydrocarbon group having 3 to 10 carbon atoms.) And the like. These may be used alone or in combination of two or more, but (a-1)
Per 100 parts by weight of the component diorganopolysiloxane,
It is used in an amount of 0.1 to 5 parts by weight, especially 0.5 to 2 parts by weight.

In the above general composition formula (I), R ¹ is a vinyl group in the organopolysiloxane having a low degree of polymerization, which is the component (B) of the composition of the present invention. R ² is a substituted or unsubstituted monovalent hydrocarbon group, preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms, such as an alkyl group such as a methyl group, an ethyl group, a propyl group or a butyl group; A cycloalkyl group such as a cyclohexyl group; or a group in which a part or all of hydrogen atoms bonded to carbon atoms of these groups are substituted with a halogen atom, a cyano group, etc., for example, a chloromethyl group, γ-trifluoropropyl Group, cyanoethyl group and the like. a is a number of 1 <a <4, and in terms of heat resistance of the obtained composition, a is preferably a number of 1.8 ≦ a ≦ 2.2. b is a number 0 ≦ b <2. However, a + b <4
Is.

Particularly in the present invention, it is extremely important that the number a, which represents the ratio of vinyl groups to silicon atoms, be greater than 1. That is, as is clear from Comparative Example 1 described later, when the above-mentioned organopolysiloxane having a of 1 or less is used (in Comparative Example 1, the organopolysiloxane of a = 1 is used), self-adhesion is performed. The sex becomes unsatisfactory.

The degree of polymerization of this organopolysiloxane is 1-1000, preferably 1-10. The organopolysiloxane having a degree of polymerization of more than 1000 reduces the adhesiveness of the resulting composition.

As the component (B), one type or a combination of two or more types of the organopolysiloxane represented by the general formula (I) can be used.

In the composition of the present invention, the blending amount of the component (B) is the silicone rubber compound of the component (A) (that is, (a-1)
~ (A-3) total amount of components) 0.1 to 10 per 100 parts by weight
Parts by weight, especially 1 to 7 parts by weight.

The composition of the present invention is a mixture of the component (A) and the component (B),
It can be manufactured by kneading by an appropriate means. Examples of the kneading means used include a two-roll, a mixing kneader, a Banbury mixer, and the like.

In the composition of the present invention, in addition to the components (A) and (B), a heat resistance improver, a colorant and other additives, for example, red iron oxide, cerium oxide, cerium hydride, fatty acid salts of cerium, iron If desired, the fatty acid salt, titanium oxide, carbon black, etc. can be added to the extent that the effects of the present invention are not impaired.

The compositions of the present invention are capable of adhering to a variety of substrates, and are particularly useful for adhering to a wide range of metals. Examples of the metal that can be adhered include iron, aluminum, nickel, chromium, zinc, tin, copper, alloys thereof, and stainless steel.

The composition of the present invention and a metal can be adhered to each other by pressing the composition of the present invention onto the surface of the metal and vulcanizing the composition by an appropriate method. The pressure of the pressure is, usually, 10~100kgf / cm ²
It is a degree. The vulcanization temperature is usually about 120 to 200 ° C. The vulcanization time is usually about 2 minutes to 30 minutes.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples.

Examples 1 to 3, Comparative Examples 1 and 2 Silicone rubber compound (K, Shin-Etsu Chemical Co., Ltd., K
E555U) 100 parts by weight and 2,5-bis- (t-butylperoxy) -2,5-dimethylhexane 0.5 parts by weight were kneaded using a two-roll mill to obtain an unvulcanized rubber. .

In each example, 2 g of each of the five types of organopolysiloxanes represented by the following formulas (a), (b) and (c), and the average composition formulas (d) and (e) were obtained as above. Vulcanized rubber 1
It was mixed with 00 g and kneaded using a two-roll mill to obtain 5 kinds of compositions.

The adhesive strength of each of the five obtained compositions was measured according to the following method.

Example 1 [Here, Vi is a vinyl group. The same applies hereinafter] Example 2 [Here, Me is a methyl group. Same below] Comparative Example 1 Example 3 (Vi) _1.27 (Me) _0.87 SiO _0.93 (d) [Polymerization degree: 15] Comparative example 2 (Vi) _1.01 (Me) _1.00 SiO _0.995 (e) [Polymerization degree: 1200] Adhesive strength Good with volatile oil Having a clean surface that has been cleaned, thickness 0.3
mm, width 25 mm, and length 50 mm, two iron plates were prepared, and as shown in FIG. 1, the iron plates 1 and 2 were faced so that the overlapping area was 1 square inch, and the composition 3 was sandwiched between them. A test piece 4 was prepared by press-curing at 165 ° C. for 10 minutes while pressure-bonding at a pressure of 50 kg / cm ² .

The ends 41 and 42 of the obtained test piece were fixed to the chuck of the tensile tester, and the tensile load was applied in the direction shown in FIG.
The maximum tensile load until breakage was measured, and this was taken as the adhesive strength. Moreover, the fracture state of the test piece was examined. The results are shown in Table 1.

[Advantages of the Invention] The composition of the present invention has good adhesiveness to a metal and can easily perform an operation of adhering to a metal. Also, since there is no problem in terms of safety of the manufacturing work,
It is of great practical value.

[Brief description of drawings]

FIG. 1 shows a test piece for a tensile test for measuring the adhesive strength of the compositions obtained in Examples of the present invention and Comparative Examples. 1, 2 ... Iron plate, 3 ... Composition, 4 ... Test piece.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C09J 183: 07)

Claims (1)

[Claims] (A-1) 100 parts by weight of diorganopolysiloxane having a degree of polymerization of 3,000 to 30,000 (a-2) Fine silica powder filler 10 to 300 parts by weight (a-3) Organic peroxide 1 to 5 parts by weight and (B) general composition formula (I): [Wherein, R ¹ is a vinyl group, R ² is a substituted or unsubstituted monovalent hydrocarbon group, a is a number of 1 <a <4, and b is 0 ≦ b <
2 is a number, where a + b <4], and the degree of polymerization is 1-1000. Organopolysiloxane 0.1 to 100 parts by weight of the total amount of the components (a-1) to (a-3). A self-adhesive silicone rubber composition containing 10 to 10 parts by weight.