JP2004076911A - Rubber metal laminate gasket - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber metal laminate gasket with an excellent waterproof adhering property even without applying a hazardous application-type chromate processing to metal at the time of forming the rubber metal laminate gasket composed of a complex of metal such as stainless steel and rubber. <P>SOLUTION: To form this rubber metal laminate gasket, (A) a silane-base basecoating agent, (B) a topcoat adhesive containing novolak type epoxy resin, phenol resin, and a tertiary amine compound, and (C) fluorine rubber are sequentially laminated on a metallic plate. A hydrolytic condensate of organoalkoxysilane, and preferably copolymeric origomer of amino group containing alkoxysilane and vinyl group containing alkoxysilane is used as the silane-base basecoating agent, and also an organic metal compound can be added to it. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rubber-metal laminated gasket. More specifically, the present invention relates to a rubber-metal laminated gasket having excellent liquid resistance to water, ethylene glycol, alcohol, LLC (long life coolant) and the like.
[0002]
[Prior art]
Stainless steel is often used to form a composite of metal and rubber that requires resistance to water and LLC, but a vulcanizing adhesive is applied directly on the stainless steel and vulcanized and bonded to the rubber. Then, the obtained stainless steel-rubber composite has poor water resistance and LLC resistance, and when these immersion tests are carried out, the adhesive peels off.
[0003]
As a countermeasure for this, a coating type chromate treatment is performed on stainless steel as a pretreatment for applying a vulcanizing adhesive, thereby improving the resistance to water and LLC. However, the coating type chromate treatment is not preferable in view of environmental measures because it contains Cr ions.
[0004]
The present applicant has previously proposed various vulcanized adhesive compositions based on alkoxysilane as an adhesive between metal and rubber when manufacturing a rubber-metal laminated gasket (Japanese Patent Laid-Open No. 7-34054). JP-A-7-216309, JP-A-8-209102, JP-A-9-3432, JP-A-9-40916, JP-A-9-132758, JP-A-10-7990, JP-A-10-80221 These vulcanized adhesive compositions are particularly suitable for bonding to a metal surface that has been chemically or physically treated in advance. When applied to an untreated metal surface, for example, it is not possible to obtain the same degree of adhesion as in the case of stainless steel subjected to a coating type chromate treatment.
[0005]
Further, although various primers for vulcanized adhesives based on phenolic resins are commercially available, they do not exhibit sufficient adhesiveness and water resistance in bonding with stainless steel.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to form a rubber-metal laminated gasket made of a composite of a metal such as stainless steel and a fluororubber, without subjecting the metal to a harmful coating-type chromate treatment or the like, a rubber having excellent water-resistant adhesion. It is to provide a metal laminated gasket.
[0007]
[Means for Solving the Problems]
The object of the present invention is to sequentially laminate (A) a silane-based primer, (B) a novolak-type epoxy resin, a phenolic resin and a tertiary amine compound-containing topcoat adhesive and (C) a fluororubber on a metal plate. Achieved by rubber-metal laminate gaskets.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
As the metal plate, a stainless steel plate, a mild steel plate, an aluminum plate, an aluminum die-cast plate, or the like is used, and preferably, a stainless steel plate such as SUS304, SUS301, or SUS430 is used. Since the plate thickness is used for a gasket, a plate having a thickness of about 0.1 to 2 mm is generally used.
[0009]
First, a silane-based primer (A) is applied on these metal plates. As the silane-based primer, a hydrolysis-condensation product of an organoalkoxysilane is used. Here, organoalkoxysilane of the general formula R ^'is represented by Si (OR) _3, R is a lower alkyl group such as a methyl group, an ethyl group, ^R' is a methyl group, an ethyl group, 3-aminopropyl group , N- (2-aminoethyl) -3-aminopropyl group, N-phenyl-3-aminopropyl group, vinyl group, 3-methacryloxypropyl group, 3-glycidoxypropyl group, 3-mercaptopropyl group, etc. It is.
[0010]
The hydrolysis-condensation reaction of the organoalkoxysilane is carried out by heating to about 40 to 80 ° C. in the presence of an acid catalyst such as formic acid while water for hydrolysis is present. Further, as such a hydrolyzed condensate, a copolymer oligomer of an amino group-containing alkoxysilane and a vinyl group-containing alkoxysilane is preferably used. Examples of the amino group-containing alkoxysilane as one component of the copolymerized oligomer include, for example, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane , N-β- (aminoethyl) -γ-aminopropyltriethoxysilane and the like. As the vinyl group-containing alkoxysilane as another component, for example, vinyltrimethoxysilane, vinyltriethoxysilane, or the like is used.
[0011]
In the oligomerization reaction, 25 to 400 parts by weight, preferably 50 to 150 parts by weight, and 20 to 150 parts by weight of water for hydrolysis are used per 100 parts by weight of the amino group-containing alkoxysilane. . If the vinyl group-containing alkoxysilane is used in a higher ratio, the compatibility with the overcoating agent or rubber becomes poor and the adhesiveness decreases, while if used in a lower ratio, the water resistance decreases. Become like
[0012]
In the oligomerization reaction, these are charged into a reactor having a distillation apparatus and a stirrer, and stirred at about 60 ° C. for about 1 hour. Thereafter, an acid, for example, formic acid or acetic acid, is added within about one hour in an amount of about 1 to 2 mol per mol of the amino group-containing alkoxysilane. The temperature at this time is kept at about 65 ° C. The mixture is further stirred for 1 to 5 hours to allow the reaction to proceed, and at the same time, the alcohol produced by the hydrolysis is distilled under reduced pressure. The distillation is terminated when only distilled water is present, and then the dilution is adjusted so that the silane concentration becomes 30 to 80% by weight, whereby the desired copolymer oligomer is obtained. This copolymerized oligomer is an oligomer that is soluble in alcoholic organic solvents such as methanol and ethanol. Further, a commercially available copolymerized oligomer can also be used as it is.
[0013]
The use of an amino / vinyl group-containing alkoxysilane copolymer oligomer for bonding a metal such as stainless steel to a fluororubber has been proposed by the present applicant (WO 02/24826). Is used as a vulcanizing adhesive, while in the present invention it is used as a vulcanizing adhesive primer and requires a separate vulcanizing adhesive.
[0014]
It is preferable that an organometallic compound is further added to these silane-based primers. Examples of the organometallic compound include triisopropoxyaluminum, monosecondary butoxydipropoxyaluminum, trisecondary butoxyaluminum, ethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate), and aluminum monoacetylacetonate bis (ethyl acetoacetate). Organic aluminum compounds such as acetate), aluminum tris (acetyl acetate), tetraisopropoxytitanium, tetra n-butoxytitanium, isopropoxytitanium bis (ethylacetoacetate), 1,3-propanedioxytitanium bis (ethylacetoacetate), Organic titanium compounds such as isopropoxytitanium bis (acetylacetonate) and titanium tetraacetylacetonate, tetra-n-propyl zirconium Organic zirconium compounds such as tetra-n-butoxyzirconium, di-n-butoxyzirconium bis (acetylacetonate), di-n-butoxyzirconium bis (ethylacetoacetate), dibutyltin dilaurate, dibutyltin dioctate, dibutyltin dilaurate, etc. An organic tin compound is exemplified.
[0015]
These organometallic compounds are used in an amount of about 100 parts by weight or less, preferably about 20 to 80 parts by weight, per 100 parts by weight of the hydrolytic condensate. The addition of the organometallic compound at such a usage ratio increases the liquid resistance to heated water, ethylene glycol or an aqueous solution thereof, alcohol, and the like, while when used at a higher ratio, the overcoating agent or The compatibility with rubber is deteriorated, and the adhesiveness is reduced. Further, depending on the use, an amine carboxylate, an inorganic filler and the like can be added to the silane-based primer and used.
[0016]
The silane-based primer having the above components as essential components is generally used in an amount of about 0.2 to 3 of an alcohol-based organic solvent such as methanol, ethanol, or isopropanol or a mixed solvent of ketone-based organic solvent such as acetone or methyl ethyl ketone and water. It is prepared and used as a solution having a concentration of% by weight. The organic solvent and water are used in a mixture such that the former is about 100 to 80% by weight and the latter is about 0 to 20% by weight. When water is used in combination, the higher molecular weight of the hydrolyzed condensate is further increased, and a tough film can be formed.
[0017]
Examples of the silane-based primer include commercially available products, for example, Chemlock AP-133 manufactured by Lord Far East Co., Metaloc S-2 manufactured by Toyo Chemical Laboratory, Megam 3290-1 manufactured by Rohm and Haas, and the like. It can be used after being diluted with an aqueous mixed solvent.
[0018]
The silane-based primer is applied on a metal plate by spraying, brush printing, roll coating, or the like, to a thickness of about 0.1 to 10 μm, dried at room temperature, and then dried at about 100 to 250 ° C. It is baked for about 1 to 20 minutes.
[0019]
A top coat adhesive (B) containing a novolak type epoxy resin, a phenol resin and a tertiary amine compound is applied on the silane base coat (A) applied on the metal plate. As the novolak epoxy resin, for example, a phenol novolak epoxy resin, an o-cresol novolak epoxy resin, or the like is used. As the phenol resin, a novolak-type phenol resin obtained by condensation polymerization of a phenol compound such as phenol, cresol, alkylphenol, and bisphenol A with formaldehyde is generally used. As the tertiary amine compound acting as a curing agent for these components, for example, 2,4,6-tris (dimethylaminomethyl) phenol, 2-methylimidazole, 2-ethyl-4-methylimidazole and the like are used.
[0020]
Each of these components contains about 20 to 60 parts by weight, preferably about 30 to 50 parts by weight of a phenolic resin, and about 0.2 to 1 part by weight of a tertiary amine compound with respect to 100 parts by weight of a novolak type epoxy resin. Parts. A solution of a ketone-based organic solvent such as acetone and methyl ethyl ketone or an alcohol-based organic solvent such as methanol, ethanol, and isopropanol is used so that the total amount of the resin-based topcoating agent composed of the above components is about 3 to 10% by weight. And the same application method, application temperature and application time as in the case of the undercoat are applied to form an overcoat layer having a thickness of about 1 to 15 μm. With respect to the overcoating agent, the same application method, application temperature, and application time as in the case of the undercoating agent are applied, and an overcoating layer having a thickness of about 1 to 15 μm is formed.
[0021]
On the adhesive layer thus formed, the unvulcanized fluororubber compound (C) is formed so as to form a single-sided vulcanizate layer having a thickness of about 5 to 120 μm. Applied as a solvent solution. The applied rubber layer is dried at a temperature of room temperature to about 100 ° C. for about 1 to 15 minutes, and after evaporating methyl ethyl ketone, toluene, xylene or a mixed solvent thereof used as an organic solvent, about 150 to Vulcanization by heating at 230 ° C. for about 0.5 to 30 minutes and, if necessary, vulcanization under pressure. The vulcanized fluororubber layer preferably has a hardness (durometer A) of 80 or more and a compression set (100 ° C., 22 hours) of 50% or less for use as a gasket. In this case, an anti-adhesive agent can be applied to the surface.
[0022]
As the fluororubber (C), any of a polyol vulcanizable and a peroxide vulcanizable can be used.
[0023]
Polyol vulcanizable fluororubbers include generally vinylidene fluoride and other fluorinated olefins such as hexafluoropropene, pentafluoropropene, tetrafluoroethylene, trifluorochloroethylene, vinyl fluoride, perfluoro (methyl vinyl ether) and the like. Copolymers with at least one kind thereof are mentioned. These fluororubbers include polyhydroxy resins such as 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) perfluoropropane and hydroquinone. The polyol is vulcanized by the aromatic compound.
[0024]
Examples of the peroxide-curable fluororubber include, for example, fluororubbers having iodine and / or bromine in the molecule. These fluororubbers are vulcanized by an organic peroxide generally used for peroxide vulcanization. It is sulfurized (crosslinked). In this case, it is preferable to use a polyfunctional unsaturated compound represented by triallyl isocyanurate together with the organic peroxide.
[0025]
【The invention's effect】
The rubber-metal laminated gasket according to the present invention has a laminated structure composed of a metal plate, a silane-based undercoat, a novolak-type epoxy resin, a phenolic resin and an overcoat containing a tertiary amine compound, and a fluororubber compound. By using an agent, preferably a hydrolyzed condensate of an organoalkoxysilane, more preferably an amino / vinyl group-containing alkoxysilane copolymerized oligomer, it has excellent resistance to heated water, ethylene glycol or its aqueous solution, alcohol and the like. It exhibits liquid properties, and its liquid resistance effect is more remarkable when one component of a silane-based primer is used in combination with an organometallic compound.
[0026]
【Example】
Next, the present invention will be described with reference to examples.
[0027]
Reference Example A three-necked flask equipped with a stirrer, a heating jacket and a dropping funnel was charged with 40 parts (weight, the same applies hereinafter) of γ-aminopropyltriethoxysilane and 20 parts of water, and acetic acid was added so that the pH became 4 to 5. And stirred for several minutes. While continuing stirring, 40 parts of vinyltriethoxysilane was gradually dropped using a dropping funnel. After completion of the dropwise addition, the mixture was heated under reflux at a temperature of about 60 ° C. for 5 hours, and cooled to room temperature to obtain a copolymerized oligomer.
[0028]
Example 1
After the surface of the surface dull finish SUS301 steel plate (thickness 0.2 mm) is alkali-degreased,
A silane-based primer comprising 2.5 parts of the above copolymerized oligomer, 87.5 parts of methanol and 10.0 parts of water was applied, dried at room temperature, and then baked at 220 ° C. for 5 minutes.
[0029]
After cooling,
24.4 parts of o-cresol novolak type epoxy resin (Japan epoxy resin product Epicoat 180S65)
9.7 parts of novolak type phenolic resin (Deno Nippon Ink and Chemicals phenolite KA-1174)
A top coat adhesive consisting of 0.1 part of 2-ethyl-4-methylimidazole and 65.8 parts of methyl ethyl ketone was applied, dried at room temperature, and baked at 210 ° C. for 5 minutes.
[0030]
In this adhesive layer,
Fluoro rubber (Viton E60C manufactured by DuPont) 100 parts Vulcanizing agent (Diac No. 3 manufactured by DuPont) 3 parts Magnesium oxide (Magnesia # 30 manufactured by Kyowa Chemical Co., Ltd.) 10 parts MT carbon black Fluoro rubber compound with a compounding ratio of 30 parts Using
A rubber solution (solid content: 25% by weight) consisting of 25 parts of a fluororubber compound, 60 parts of methyl isobutyl ketone and 15 parts of methanol is applied and dried at 60 ° C. for 15 minutes to form an unvulcanized rubber layer having a thickness of 20 μm on one side. After the formation, pressure vulcanization was performed at 180 ° C. and 60 kgf / cm ² for 10 minutes to obtain a rubber-metal laminated gasket.
[0031]
This rubber-metal laminated gasket was subjected to a strip tape test according to the method of JIS K-5400 8.5.2. The test was carried out initially and in each case by immersing water, ethylene glycol (EG), 50% by weight aqueous solution of EG, ethanol at 120 ° C. in a pressurized solution for 70 hours.
[0032]
Example 2
In the silane-based primer of Example 1, the amount of methanol was changed to 86.5 parts, and one part of aluminum tris (acetyl acetate) was added thereto.
[0033]
Example 3
In the silane-based primer of Example 1, the amount of methanol was changed to 86.5 parts, and 1 part of titanium tetra (acetylacetate) was added thereto.
[0034]
Example 4
In the silane-based primer of Example 1, the amount of methanol was changed to 86.5 parts, and 1 part of di-n-butoxyzirconium bis (ethylacetoacetate) was added thereto.
[0035]
Example 5
In the top coat adhesive of Example 4, the same amount of phenol novolak type epoxy resin (Epicoat 154 manufactured by Japan Epoxy Resin) was used in place of the o-cresol novolak type epoxy resin.
[0036]
Example 6
In Example 4, as the fluororubber compound forming the solid content of the rubber solution,
A fluorine rubber compound having a compounding ratio of 100 parts of fluororubber (Viton B manufactured by DuPont), 15 parts of lead oxide (PbO), 15 parts of a vulcanizing agent (Diac No. 4 manufactured by DuPont), 3 parts of MT carbon black and 20 parts of MT carbon black was used.
[0037]
Comparative Example 1
In Example 1, no silane-based primer was used.
[0038]
Comparative Example 2
In Example 4, no overcoat adhesive was used.
[0039]
Comparative Example 3
In Example 4, a commercially available primer (Metaloc PA-3375 manufactured by Toyo Chemical Laboratory) was used in place of the silane-based primer.
[0040]
Comparative Example 4
In Example 4, a commercial topcoat adhesive (Monicas VT-100 manufactured by Yokohama Polymer Research Institute) was used in place of the topcoat adhesive containing a novolak epoxy resin, a phenolic resin, and a tertiary amine compound.
[0041]
Comparative Example 5
Example 4
Bisphenol A type epoxy resin 21.5 parts (Epicoat 828 from Japan epoxy resin product)
A novolak type phenol resin (Phenolite KA-1174) was used. A top coat adhesive composed of 9.7 parts of 2-ethyl-4-methylimidazole 0.1 part of methyl ethyl ketone 65.8 parts was used.
[0042]
The measurement results in the above Examples and Comparative Examples are shown in the following table.

Claims (6)

A rubber-metal laminated gasket obtained by sequentially laminating (A) a silane-based primer, (B) a novolak-type epoxy resin, a phenolic resin and a tertiary amine compound on a metal plate, and (C) a fluororubber. The rubber-metal laminated gasket according to claim 1, wherein the metal plate is a stainless steel plate. The rubber-metal laminated gasket according to claim 1, wherein the silane-based primer is a hydrolytic condensate of an organoalkoxysilane. The rubber metal-laminated gasket according to claim 3, wherein the hydrolysis condensate of the organoalkoxysilane is a copolymerized oligomer of an amino group-containing alkoxysilane and a vinyl group-containing alkoxysilane. 5. The rubber-metal laminated gasket according to claim 1, wherein the organometallic compound is further added to the silane-based primer. The rubber-metal laminated gasket according to claim 1, which is used for contact with water, ethylene glycol, alcohol or LLC.