JPH03111452A - Self-adhesive silicone rubber composition - Google Patents

Abstract

PURPOSE:To obtain the title compsn. which has excellent adhesive properties and with which adhesion can be easily performed by compounding each specified silicone rubber compd. and organopolysiloxane. CONSTITUTION:The title compsn. comprises an org. peroxide-curing type silicone rubber compd. (e.g. KE555U, a product of Shinetsu Chem. Co., Ltd.) and an organopolysiloxane of formula I (wherein R<1> is a monovalent org. group with an unsatd. bond; R<2> is a monovalent hydrocarbon group; 1<a<4; 0<=b<2; a+b<4) with a degree of polymn. of 1-1,000, e.g. a compd. of formula II (wherein Vi is a vinyl group).

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a self-adhesive silicone rubber composition, particularly a self-adhesive silicone rubber composition that has good adhesion to metals and can be easily bonded. The present invention relates to a silicone rubber composition.

[Conventional technology]

Silicone rubber is used for various purposes due to its excellent properties. This silicone rubber is also used in the form of a composite formed by adhering it to 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 adhere the silicone rubber and metal.

As this primer, a composition consisting of an alkoxysilane having an unsaturated bond, a hydrolyzed condensate thereof, or a co-hydrolyzed siloxane, a titanate ester, and a metal salt of an organic fatty acid (Japanese Patent Publication No. 17622/1983, 62 -17623) ; Alkoxysilane having an unsaturated bond or a hydrolyzed condensate or co-hydrolyzed siloxane thereof, a titanate ester, a metal salt of an organic fatty acid and: ;5t-I! A composition consisting of an organosilicon compound having a group (Japanese Patent Publication No. 61-2107): A rubber-like composition consisting of a vinyl group-containing organopolysiloxane, a polysiloxane resin, an alkoxysilane, an organic peroxide, and a titanate ester (Japanese Patent Publication No. 61-2107) Special Public Service No. 56-39817
) have been proposed.

[Problem to be solved by the invention]

However, when bonding silicone rubber to metal using these conventional primers, after applying the primer to the object to be bonded, air-drying or baking steps are essential in order to volatilize the solvent and solidify the primer. There was a problem that the adhesion work was complicated. Furthermore, conventional primers contain a hydrolytic condensate, a catalyst, or a solvent, which poses a problem in terms of safety during manufacturing operations.

Therefore, the object of the present invention is to provide a product that has good adhesion to metals, allows easy adhesion work, and does not contain hydrolyzed condensates, catalysts, or solvents, so there is no problem in terms of safety in manufacturing work. An object of the present invention is to provide a self-adhesive silicone rubber composition that does not cause adhesive bonding.

[Means to solve the problem]

In order to solve the above problems, the present invention provides (A) an organic peroxide-curable thermosetting silicone rubber compound and (B) a general compositional formula (I); (R1)a(R2)bSiO(4-( R2) bsio
, +i(1) [wherein R' is a monovalent organic group containing an unsaturated bond, R2 is a substituted or unsubstituted monovalent hydrocarbon group, a is the number l<a<4, b is a number of O≦b<2,
provided that a+b<4] A self-adhesive silicone rubber composition containing an organopolysiloxane having a degree of polymerization of 1 to 1000 is provided.

The organic peroxide-curable thermosetting silicone rubber compound, which is component (A) of the composition of the present invention, typically includes (1) diorganopolysiloxane, (2) finely powdered silica filler, and (3) ) A composition containing an organic peroxide as an essential component can be mentioned.

The diorganopolysiloxane as the first component has, for example, the formula: % formula % [Here, R3 is a methyl group, an ethyl group, a propyl group,
Alkyl groups such as butyl groups, alkenyl groups such as vinyl groups, allyl groups, and butenyl groups; aryl groups such as phenyl groups and tolyl groups; or some or all of the hydrogen atoms bonded to the carbon atoms of these groups are replaced with halogen atoms. , chloromethyl group, chloropropyl group substituted with cyano group, etc., 3,
3.3-) Same or different unsubstituted or substituted monovalent hydrocarbon groups having 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, selected from a lifluoropropyl group, a 2-cyanoethyl group, etc. and C is a number from 1.95 to 2.05. ] Examples include the following. In the diorganopolysiloxane, 98% or more of R3 in the above formula is an alkyl group having 1 to 4 carbon atoms, particularly a methyl group,
Other examples of R3 include those containing a vinyl group, a phenyl group, and a trifluoropropyl group. Further, although the molecular structure is preferably linear, the molecule may contain a branched chain partially. In addition, the degree of polymerization is usually 3,000 to 30,
000 to 4,000 to 4,000 t from the viewpoint of workability.
o, oooO are preferred.

In addition, the fine powder silica filler as the second component in the silicone rubber compound (A) is added for the purpose of reinforcing, thickening, improving processability, and increasing the amount of silicone rubber, and this includes fumed silica. Examples include wet silica, fumed silica with a hydrophobized surface, wet silica, fine quartz powder, diatomaceous earth, etc., which may be combined with other forms of fillers such as calcium silicate, calcium carbonate, carbon black, glass fiber, etc. The specific surface area of these particles is preferably 7 g or more per 1 cm, preferably 7 g or more per 50 m.

Note that if the amount of this compound is too small, the desired reinforcing properties will not be obtained and the processability will also be insufficient. On the other hand, if the amount is too large, processing properties such as mold flowability and dischargeability will be extremely degraded. Generally, the amount is preferably in the range of 10 to 300 parts by weight, more preferably 25 to 200 parts by weight, per 100 parts by weight of the first component organopolysiloxane.

(A) The third component in the silicone rubber compound.
Examples of the organic peroxide as a component include t-butyl peroxide, dicumyl peroxide, benzoyl peroxide, monochlorobenzoyl peroxide,
p-methylbenzoyl peroxide, 2.4-dichlorobenzoyl peroxide, t-butyl perbenzoate, 2.5-bis-(1-butylperoxy)-2,
5-dimethylhexane, 2,5-bis-(t-butylperoxy)-2,5dimethylhexine; dicarbonates such as similistilperoxycarbonate, dicyclododesilver oxydicarbonate; t-butyl monoper Examples of oxycarbonates include compounds represented by the following formula: (wherein R4 is a monovalent hydrocarbon group having 3 to 10 carbon atoms). These may be used alone or in combination of two or more, but the blending amount is 10% of the diorganopolysiloxane as the first component.
It is usually 0.1 to 5 parts by weight, preferably 0.5 to 2 parts by weight relative to 0 parts by weight.

In the above formula (1) representing the organopolysiloxane which is the component (B) of the composition of the present invention, R1 is a monovalent organic group containing an unsaturated bond, and is typically a substituted or unsubstituted hydrocarbon group. groups, preferably hydrocarbon groups having 2 to 8 carbon atoms, such as alkenyl groups such as vinyl groups and allyl groups;
Examples include aryl groups such as phenyl group and tolyl group, and (meth)acryloyl group. R2 is a substituted or unsubstituted monovalent hydrocarbon group, preferably having a carbon atom number of '1'
~10 monovalent hydrocarbon groups, such as alkyl groups such as methyl, ethyl, propyl, and butyl; cycloalkyl groups such as cyclohexyl; or hydrogen atoms bonded to carbon atoms of these groups. Examples include groups partially or entirely substituted with a halogen atom, a cyano group, etc., such as a chloromethyl group, a γ-trifluoropropyl group, a cyanoethyl group, and the like. a is a number of 1<a<4,
In terms of heat resistance of the resulting composition, a is 1.8≦a≦2.2.
It is preferable that the number is . b is a number satisfying 0≦b<2. However, a+b<4.

The degree of polymerization of this organopolysiloxane is 1 to 1000,
Preferably it is 1-10. If the organopolysiloxane has a degree of polymerization exceeding 1000, the adhesiveness of the resulting composition will decrease.

As component (B), one type or a combination of two or more types of organopolysiloxanes represented by the general formula (1) can be used.

The blending ratio of component (^) and component (B) in the composition of the present invention is usually 0.1 to 0.1 to 100 parts by weight of component (A) to 100 parts by weight of component (A) in order to obtain a suitable adhesive strength. The amount is 10 parts by weight, preferably 1 to 7 parts by weight.

The composition of the present invention can be produced by mixing the components (A) and (B) and kneading the mixture by appropriate means. Examples of the kneading means used include two rolls, a mixing kneader, and a Banbury mixer.

In addition to components (A) and (B), the composition of the present invention may contain heat resistance improvers, colorants, and other additives, such as red iron, cerium oxide, cerium hydroxide, cerium fatty acid salts, and iron. Fatty acid salts, titanium oxide, carbon black, etc. may be added as necessary to an extent that does not impair the effects of the present invention.

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 bondable metals include iron, aluminum, nickel, chromium, zinc, tin, copper, alloys thereof, and stainless steel.

The composition of the present invention can be bonded to metal by pressing the composition of the present invention onto the surface of the metal and vulcanizing it by an appropriate method. The crimping pressure is usually 10-10-1
It is about O0/cm2. Vulcanization temperature is usually 120~
The temperature is about 200°C. Vulcanization time is usually 2 minutes to 30 minutes.
It takes about a minute.

〔Example〕

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

Examples 1 to 3, Comparative Examples 1 to 2 Silicone rubber compound (manufactured by Shin-Etsu Chemical Co., Ltd., K
An unvulcanized rubber was obtained by kneading 100 parts by weight of E555tJ) and 0.5 parts by weight of 2,5-bis-(t-butylperoxy)-2,5-dimethylhexane using two rolls.

On each side, 2 g of each of the five organopolysiloxanes represented by the following formulas (a), (b) and (C) and average compositional formulas (d) and (e) were added to The mixture was mixed with 100 g of vulcanized rubber and kneaded using two rolls to obtain five types of compositions.

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

〔here, Vi is a vinyl group.

same as below〕 〔here, Me is a methyl group.

The same applies hereafter] (Vi) +, zt(Me) o, atsiOo,
qz(d) [Polymerization degree: 15] This fi turtle (Vi) r, or (Me) r, oosioo
, 995 (e) [degree of polymerization: 1200
) Thickness 0.1 with a clean surface thoroughly washed with volatile oil.
Two iron plates with a diameter of 3 mm, a width of 25 mm, and a length of 50 Illl are prepared, and as shown in FIG. 1, iron plates 1 and 2 are faced so that the overlapping area is 1 square inch, and composition 3 is sandwiched between them. , press cured at 165°C for 10 minutes while pressing at a pressure of 50 kg/afl to obtain test piece 4.
was created.

The ends 41 and 42 of the obtained test piece were fixed to the chuck of a tensile testing machine, and a tensile load was applied in the direction shown in Figure 1 at a tensile speed of 1 mm/min, and the maximum tensile load until breakage was measured. was taken as the adhesive force. The fracture state of the test piece was also examined. The results are shown in Table 1.

Table note) Ne: Interface between rubber and iron piece [Effects of the invention] The composition of the present invention has good adhesion to metals, can be easily bonded to metals, and can be manufactured easily. It has great practical value as it does not cause any problems in terms of work safety.

[Brief explanation of drawings]

FIG. 1 shows a tensile test specimen for measuring the adhesive strength of the compositions obtained in Examples and Comparative Examples of the present invention. 1.2・----------1--・Iron plate, 3-・-・-
・-・・Composition, 4-・・・・・・Test piece.

Claims (1)

[Claims] (A) Organic peroxide-curable thermosetting silicone rubber compound and (B) General compositional formula (I): (R^1)_a(R^2)_bSiO_(_4_-_a
___b_)_/_2(I) [In the formula, R^1 is a monovalent organic group containing an unsaturated bond, R^2 is a substituted or unsubstituted monovalent hydrocarbon group, and a is 1 A self-adhesive silicone rubber composition containing an organopolysiloxane with a degree of polymerization of 1 to 1000, where b is a number of 0≦b<2, where a+b<4. thing.