JPH06279732A - Primer composition for bonding fluororubber - Google Patents

Abstract

PURPOSE:To obtain a primer compsn. which strongly bonds various adherends made of fluororubbers vulcanizable with an org. peroxide and forms an adhesive layer excellent in heat resistance, oil resistance, etc., by compounding specific components. CONSTITUTION:A primer compsn. for bonding fluororubbers vulcanizable with an org. peroxide is obtd. by compounding a silane coupling agent of formula I [wherein R<1> is a monovalent group having a carbon-carbon unsatd. bond; R<2> is a (substd. monovalent group; R<3> is a hydrolyzable monovalent group; and a is 1, 2, or 3 and b is 0, 1, or 2 provided a+b is 1, 2, or 3] or its partially hydrolyzed condensate, at least either an organic silicate (or its partially hydrolyzed condensate) or a polyalkoxyorganosiloxane of formula II [wherein R<4> to R<7> are each a (substd.) monovalent group; p is 0-2; q is a positive integer of 1 or higher; and r is 0. 5-4], and at least either an org. titanic ester or an aluminum alkoxide.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a primer composition, and more particularly to an organic peroxide vulcanizable fluororubber adhesive primer composition.

[0002]

2. Description of the Related Art Conventionally, epoxy-based primers have been widely used as a primer for adhering fluororubber to various adherends during vulcanization molding because they have excellent adhesive strength. When a substance-vulcanized fluororubber is used, the adhesion to various adherends is not always sufficient, and the heat resistance and oil resistance of the primer layer are not satisfactory. Further, the silane coupling agent-based primer did not provide sufficient adhesive strength.

[0003]

The object of the present invention is to provide various metals having excellent heat resistance, oil resistance, water resistance, etc., and at the time of vulcanization molding of organic peroxide vulcanized fluororubber, It is intended to provide a primer composition having a strong adhesive strength when it is adhered to glass, ceramics, resin, wood and the like.

[0004]

The present invention has been made to solve the above-mentioned problems, and includes the following (A):
The above problems are solved by a primer composition containing (B) and (C) for adhering a fluororubber capable of vulcanizing an organic peroxide. (A) A silane coupling agent represented by the following (1) or a partial hydrolysis-condensation product thereof, R ¹ _a SiR ² _b R ³ _4-ab ··· (1) (where R ¹ is a carbon-carbon A monovalent group having a saturated bond,
R ² is a substituted or unsubstituted monovalent group, R ³ is a hydrolyzable monovalent group, and when R ¹ , R ² and R ³ are respectively plural, they are the same or different groups, and a is 1, 2 or 3 , B is 0, 1 or 2,
a + b is 1, 2 or 3) (B) at least one selected from organic silicic acid esters or partial hydrolysis-condensation products thereof, and polyalkoxyorganosiloxanes represented by the following (2): [R ⁴ O- (SiR ⁵ R ⁶ -O) _q ] _r SiR ⁷ _p O _{(4-pr) / 2} ... (2) (wherein R ⁴ , R ⁵ , R ⁶ and R ⁷ are substituted or unsubstituted monovalent groups, R ⁴ , R ⁵ , R ⁶ , and R ⁷ are the same or different when they are respectively plural, p is a positive number of 0 to 2, q is a positive integer of 1 or more,
r is a positive number of 0.5 to 4) (C) At least one selected from organic titanate esters and aluminum alkoxides.

The fluororubber to which the primer composition of the present invention is applied is a conventionally known organic peroxide vulcanizable one, and is a vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene. -Tetrafluoroethylene copolymer, tetrafluoroethylene-propylylene copolymer, vinylidene fluoride-tetrafluoroethylene-propylylene copolymer or vinylidene fluoride-perfluoroalkyl vinyl ether copolymer, etc. It is possible to vulcanize the organic peroxide by polymerizing or introducing an unsaturated bond.

Since the silane coupling agent represented by (1) of the component (A) used in the present invention has a hydrolyzable group and an alkenyl group, various silanol groups produced by hydrolysis are covered. The fluororubber and various adherends adhere to each other by chemically bonding to the adherend and co-vulcanizing one of the alkenyl groups with the fluororubber with an organic peroxide during vulcanization of the fluororubber.

Specific examples of the component (A) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (β-methoxyethoxy) silane, vinyltriacetoxysilane, vinyltris (methylethylketoxime) silane, vinylmethyldimethoxysilane and allyl. Examples thereof include trimethoxysilane, allyltriethoxysilane, and the like, or partial hydrolysis-condensation products of these silanes and partial co-hydrolysis condensation products of two or more kinds of silanes. These may be used alone or as a mixture of two or more.

The component (B) organic silicic acid ester or its partial hydrolyzed condensate used in the present invention and the polyalkoxysiloxane represented by (2) are co-hydrolyzed with the component (A) to form a primer layer. To improve the film-forming property and improve the adhesive strength and heat resistance. Among them, since the polyalkoxyorganosiloxane represented by (2) has a flexible skeleton structure, the heat resistance of the primer layer is further improved by using it in combination with an organic silicate ester.

Specific examples of the organic silicic acid ester as the component (B) include tetramethyl orthosilicate, tetraethyl orthosilicate, tetra-n-propyl orthosilicate, tetra (β-methoxyethyl) orthosilicate, and the like. Partially hydrolyzed condensates and partially co-hydrolyzed condensates of two or more silicates may be mentioned. These may be used alone or as a mixture of two or more.

Examples of the polyalkoxyorganosiloxane represented by (2) include polyethoxydimethylsiloxane, polyethoxymethylvinylsiloxane, polymethoxydimethylsiloxane, polyethoxytrifluoropropylmethylsiloxane and the like. These may be used alone or as a mixture of two or more.

The component (C) organic titanate and aluminum alkoxide used in the present invention are
The purpose of the invention is to accelerate the hydrolysis of the components (A) and (B), and, surprisingly, as the component (C), particularly an organic titanate ester, when the fluororubber is adhered to various adherends as in the present invention. Shows a remarkable effect, and the adhesiveness and the heat resistance of the primer layer are further improved.

Specific examples of the component (C) include tetra-n.
-Butyl titanate, tetra-n-propyl titanate, diisopropoxy titanium acetylacetonate, aluminum acetylacetonate, aluminum-n-
Examples thereof include butoxide and the like, or condensates of these and co-condensates of two or more kinds. These may be used alone or as a mixture of two or more.

The proportions of the component (A), the component (B) and the component (C) used are not particularly limited, but the amount of the component (A) is 5 to 5.
80% by weight, preferably 10 to 50% by weight, (B) component is 3 to 50% by weight, preferably 5 to 30% by weight, (C)
The component is 1 to 30% by weight, preferably 3 to 20% by weight.

The unsaturated polyfunctional compound as the component (D) and the organic peroxide used in the present invention co-vulcanize the alkenyl group of the component (A) in the primer layer and the fluororubber during the vulcanization of the fluororubber. It serves as a vulcanization aid in the curing, and these increase the crosslink density of the primer layer and improve heat resistance, oil resistance and the like. As the component (D), at least one of an unsaturated polyfunctional compound and an organic peroxide may be used, but it is more effective to use both in combination. As the unsaturated polyfunctional compound and the organic peroxide as the component (D), any of those generally used for the vulcanization of organic peroxides in rubber can be used.

Specific examples of the unsaturated polyfunctional compound as the component (D) include triallyl isocyanurate, triallyl cyanurate, trialkyl formal, trimethylolpropane trimethacrylate, diallyl phthalate and the like. Further, specific examples of the organic peroxide of the component (D) include 2,5-dimethyl-2,5-ditertiarybutylperoxyhexane, 2,5-dimethyl-2,
5-ditertiary butylperoxyhexyne-3, dicumyl peroxide, benzoyl peroxide,
α, α'-bis (tertiary butyl peroxy) -p
-Diisopropylbenzene and the like. These (D) components are used alone or as a mixture of two or more kinds. The amount of component (D) used is not particularly limited because it may exert a catalytic effect, but
It is 10% by weight, preferably 0.5 to 5% by weight.

The fluororubber of the component (E) used in the present invention or its composition is originally intended to improve the oil resistance of the primer layer due to the excellent oil resistance of the fluororubber, and is adhered during vulcanization. It is preferable that the composition is the same as or similar to that of the fluororubber.

When the component (E) is a fluororubber capable of vulcanizing an organic peroxide, the component (E) in the primer layer is
It is more preferable because the component co-vulcanizes with the alkenyl group in the component (A) and the fluororubber to be adhered during vulcanization. (E)
The component fluororubber may be used as a composition in which various fillers, additives, vulcanizing agents and the like are mixed.

Specific examples of the component (E) include vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, tetrafluoroethylene-propyleneylene copolymer, and fluorinated. Vinylidene-tetrafluoroethylene-propylylene copolymer or vinylidene fluoride-
Examples thereof include perfluoroalkyl vinyl ether copolymers and the like, and copolymers thereof with iodine or bromine-containing monomers, or by introducing an unsaturated bond to enable organic peroxide vulcanization. The amount of component (E) used is not particularly limited, but is 1 to 20% by weight, preferably 5 to 10% by weight.
Is.

Since the silane coupling agent represented by (3) of the component (F) used in the present invention has a hydrolyzable group and an amino group, vinylidene fluoride as a fluororubber is a copolymerization component. When a fluororubber contained as is used, the silanol groups produced by hydrolysis chemically bond with various adherends, and one amino group chemically bonds with the vinylidene fluoride moiety in the fluororubber during vulcanization. , To make the adhesion between the fluororubber and various adherends more effective.

Specific examples of the component (F) include γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane and N-β.
Examples thereof include-(aminoethyl) -γ-aminopropylmethyldiethoxysilane and the like, or partial hydrolysis-condensation products of these silanes and partial co-hydrolysis condensation products of two or more silanes. These are used alone or as a mixture of two or more kinds. The amount of the component (F) used is not particularly limited,
It is 5 to 40% by weight, preferably 10 to 20% by weight.

The primer composition of the present invention can be easily prepared simply by mixing the above-mentioned components, but an organic solvent, water or a mixed solvent thereof may be added to facilitate the handling during production or use. It may be dissolved. At that time, the amount of the solvent used is arbitrary and is determined depending on the use conditions and the like.
The primer composition of the present invention is mixed with other additives such as other silane coupling agents, titanate coupling agents, carbon black, silica, various metal oxide powders and pigments, as long as the performance is not impaired. May be.

The primer composition of the present invention is effective in adhering fluororubber to various adherends. As the adherend, metals such as iron, stainless steel, aluminum, brass, copper and nickel, vinyl chloride resin, polycarbonate, polyurethane, polyethylene, nylon,
Polyimide, polyester, PPS, PTFE, ETF
Thermoplastic resins such as E, natural rubber, rubbers such as SBR, NBR, silicone rubber and fluororubber, unsaturated polyester, urethane resin, silicone resin, phenol resin,
Examples thereof include thermosetting resins such as epoxy resins, fiber reinforced plastics, glass, ceramics, wood, stones and the like, or those whose surfaces are chemically or physically treated.

The primer composition of the present invention is applied to the surface of various adherends and dried, and a fluororubber of peroxide vulcanization is brought into contact with the surface to vulcanize the fluororubber and various adherends. Adheres firmly. You may pressurize with a press etc. at the time of vulcanization. The drying condition after applying the primer is in the range of several minutes to 24 hours at room temperature, but it may be longer than that range. Moreover, you may heat-dry at 40-250 degreeC for about several seconds-24 hours, and irradiate with an ultraviolet ray or an electron beam. Further, by mixing the primer composition of the present invention into fluororubber, it is possible to impart adhesiveness to the fluororubber and develop self-adhesiveness.

The primer composition of the present invention comprises a fluororubber other organic peroxide vulcanizable rubber such as natural rubber,
It can also be used as a bonding primer for styrene butadiene rubber, butadiene rubber, isoprene rubber, silicone rubber, ethylene propylene rubber and the like. The primer composition of the present invention may be used not only as a primer but also as an adhesive agent for a vulcanized rubber and various adherends. In that case, it is preferable to cure the adhesive layer.

[0025]

In the present invention, a silane coupling agent containing an alkenyl group, an organic silicic acid ester and a polyalkoxyorganosiloxane are cohydrolyzed with an organic titanic acid ester or the like to form a flexible and strong primer layer. The alkenyl group in the silane coupling agent is co-vulcanized with the fluororubber to firmly adhere to the fluororubber.

[0026]

EXAMPLES Examples will be described below. In the examples, "parts" means "parts by weight". In addition, in Table 1, “real” indicates an example and “ratio” indicates a comparative example.

Reference Example 100 parts of fluororubber Aflas 150P (tetrafluoroethylene / propylene copolymer manufactured by Asahi Glass Co., Ltd.), 30 parts of MT carbon, 5 parts of triallyl isocyanurate, and 1 part of perhexa-2,5B were uniformly mixed with 2 rolls. A fluororubber composition was obtained (fluororubber-1). 100 parts of fluororubber Afras 200 (tetrafluoroethylene / propylene-based copolymer manufactured by Asahi Glass Co., Ltd.), 30 parts of MT carbon,
5 parts triallyl isocyanurate and perhexa-2
1 part of 5B was uniformly mixed with 2 rolls to obtain a fluororubber composition (fluororubber-2).

100 parts of fluororubber Viton GF (vinylidene fluoride / hexafluoropropylene / tetrafluoroethylene copolymer manufactured by DuPont), MT carbon 3
A fluororubber composition was obtained by uniformly mixing 0 parts, 5 parts of zinc oxide, 5 parts of triallyl isocyanurate and 1 part of perhexa-2,5B with 2 rolls (fluororubber-3). 100 parts of fluororubber Viton GLT (tetrafluoroethylene / perfluoromethyl vinyl ether copolymer manufactured by DuPont), 30 parts of MT carbon, 5 parts of carbite (calcium hydroxide of Omi Chemical Co., Ltd.), 5 parts of triallyl isocyanurate and perhexa. 1,5B1 part was uniformly mixed with 2 rolls to obtain a fluororubber composition (fluororubber-4). These were used in the following tests.

Examples 1 to 12 and Comparative Examples 1 to 5 Primer compositions were prepared according to the compositions shown in Tables 1 to 3. These were applied to an adherend and subjected to the drying conditions shown in Tables 1 to 3, and then the fluororubber composition obtained above was brought into contact with it and press-vulcanized at 170 ° C. for 10 minutes. The test piece was peeled off, and the area where the fluororubber cohesively failed was measured.
Further, the bonded test piece was heated at 230 ° C. for 70 hours, and then the same test was conducted to examine the heat resistance. Further, the bonded test piece was tested according to JIS No. Dip in 3 oils, 7 at 175 ° C
After heating for 0 hour, the same test was performed to examine the oil resistance. The results are shown in Tables 1 to 3.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

[0033]

EFFECT OF THE INVENTION The primer composition of the present invention firmly adheres the organic peroxide vulcanized fluororubber to various adherends, and has excellent heat resistance and oil resistance of the adhesive layer. Therefore, the industrial benefits of the present invention are extremely large.
Molded products obtained by adhering various kinds of adherends to the fluororubber obtained according to the present invention are used for oil seals and oil drilling parts of transportation vehicles such as automobiles and airplanes, and other general industrial parts requiring heat resistance and oil resistance. Extremely useful.

Claims (5)

[Claims] 1. A primer composition for bonding an organic peroxide vulcanizable fluororubber containing the following (A), (B) and (C). (A) A silane coupling agent represented by the following (1) or a partial hydrolysis-condensation product thereof, R ¹ _a SiR ² _b R ³ _4-ab ··· (1) (where R ¹ is a carbon-carbon A monovalent group having a saturated bond,
R ² is a substituted or unsubstituted monovalent group, R ³ is a hydrolyzable monovalent group, and when R ¹ , R ² and R ³ are respectively plural, they are the same or different groups, and a is 1, 2 or 3 , B is 0, 1 or 2,
a + b is 1, 2 or 3) (B) at least one selected from organic silicic acid esters or partial hydrolysis-condensation products thereof, and polyalkoxyorganosiloxanes represented by the following (2): [R ⁴ O- (SiR ⁵ R ⁶ -O) _q ] _r SiR ⁷ _p O _{(4-pr) / 2} ... (2) (wherein R ⁴ , R ⁵ , R ⁶ and R ⁷ are substituted or unsubstituted monovalent groups, R ⁴ , R ⁵ , R ⁶ , and R ⁷ are the same or different when they are respectively plural, p is a positive number of 0 to 2, q is a positive integer of 1 or more,
r is a positive number of 0.5 to 4) (C) At least one selected from organic titanate esters and aluminum alkoxides. 2. The primer composition according to claim 1, containing at least one selected from unsaturated polyfunctional compounds and organic peroxides. 3. The primer composition according to claim 1, which contains a fluororubber. 4. The primer composition according to claim 3, wherein the fluororubber is a copolymer containing vinylidene fluoride as a copolymerization component. 5. A silane coupling agent represented by the following (3) or a partially hydrolyzed condensate thereof is contained.
The primer composition of. [H ₂ N- (CH ₂ CH ₂ NH) _x -R ⁸ ] _y -SiR ⁹ _z R ¹⁰ _4-yz ... (3) (wherein R ⁸ is a divalent hydrocarbon group, R ⁹ is A substituted or unsubstituted monovalent group, R ¹⁰ is a hydrolyzable monovalent group, R ⁸ , R ⁹ ,
When each R ¹⁰ is plural, the same or different groups, x is 0
Or an integer of 1 to 4, y is 1, 2 or 3, z is 0, 1
Or 2, y + z is 1, 2 or 3)