JPH0586987B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for bonding metal and fluororubber. More specifically, the present invention relates to a method of bonding metal and fluororubber using a vulcanized adhesive composition. [Prior Art] Conventionally, organic silane adhesives have been mainly used for adhesion between metals and fluorocarbon rubber.
When bonding with this adhesive, there is a problem with heat resistance after bonding, especially when the temperature of secondary vulcanization is 200℃.
In the above cases, hydrogen fluoride generated from the fluororubber often causes peeling on the metal surface. [Problems to be Solved by the Invention] Therefore, the present inventor conducted various efforts in search of an adhesive compound that would provide sufficient adhesive strength between metal and fluoro rubber even when heat-treated at high temperatures. As a result of investigation, it has been found that a vulcanized adhesive formulation containing the following components fully satisfies these objectives. [Means for Solving the Problems] and [Operation] Therefore, the present invention relates to a method of bonding metal and fluoro rubber, and the bonding between metal and fluoro rubber is performed using novolac type epoxy resin, novolac type phenol. applying a vulcanized adhesive formulation containing a resin and a curing agent of the novolac type phenolic resin onto the metal;
After carrying out a baking treatment as necessary, it is brought into contact with unvulcanized fluororubber and vulcanized under pressure at the vulcanization temperature of the fluororubber. The novolak type epoxy resin, which is a component of the vulcanizable adhesive formulation, is represented by the following general formula.

[Chemical] Novolac-type epoxy resin is a component used to further improve the heat resistance, chemical resistance, and adhesive properties of adhesives.It is a component that is used to further improve the heat resistance, chemical resistance, and adhesive properties of adhesives. It is produced by converting a hydroxyl group into glycidyl ether. The other component, novolac type phenolic resin, is represented by the following general formula.

[C] In this way, novolac type phenolic resin is
By reacting phenol or alkyl-substituted phenol with formaldehyde under an acid catalyst, it is obtained as a resin-like substance that is soluble in organic solvents such as alcohols and ketones. By heating, an insoluble and infusible phenolic resin is formed. In the present invention, the melting point is approximately 100 to 150°C.
Those with a molecular weight of about tens of thousands are used. Amine compounds or phosphorus compounds are generally used as curing agents for novolak type phenolic resins. As the amine compound, those represented by the following general formula are used. (a) H _z N (C _o H _zo NH) _n C _o H _zo NH _z m: Positive integer up to 0 or 25 n: Positive integer (b) H _z N−R ₃ −NH _z R ₃ :

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【formula】

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【formula】 〔Effect of the invention〕

When bonding metal and fluoro rubber using a vulcanized adhesive compound containing a novolac type epoxy resin and a novolac type phenolic resin as main components, the bonded material remains stable on the metal surface even when subjected to high temperature treatment. In particular, it has the effect of hardly causing any peeling even on metal surfaces such as aluminum, copper, zinc, etc., which often peel off in such cases. This effect is exhibited regardless of the type of vulcanizing agent used for fluoro rubber, such as amine, polyol, or peroxide, and provides stable adhesion to the adhesive. In addition, it effectively prevents corrosion of metals due to hydrogen fluoride generated from fluorine gas during heating. The vulcanization bonding of metal and fluoro rubber performed by the method of the present invention is suitably applied to the production of oil seals, valve stem seals, reed valves, valve parts, and the like. [Example] Next, the present invention will be explained with reference to an example. Example 1 Vulcanized adhesive consisting of 100 parts of novolac type epoxy resin (ECN1299 manufactured by Nippon Ciba Geigy) (weight, same hereinafter), 100 parts of novolac type phenolic resin, 10 parts of hexamethylenetetramine, 1000 parts of methyl ethyl ketone and 1000 parts of methanol. The formulation was applied onto a mild steel plate treated with a zinc phosphate coating, air-dried at room temperature for 30 minutes, and then baked at 180°C for 10 minutes. Next, on the mild steel plate on which the vulcanized adhesive composition was baked, an unvulcanized fluoro rubber made from the above formulation example was brought into contact, and pressure vulcanization was performed at 180°C for 8 minutes. The sulfurized adhesive was heat treated at 200°C for 22 hours. Example 2 In Example 1, as the unvulcanized fluororubber, the one in the formulation example described above was used. Comparative Example In Example 1, the zinc phosphate coated mild steel sheet and the unvulcanized fluoro rubber were bonded using an organosilane adhesive, and the pressure vulcanizate was cured at 180°C for 8 minutes. Heat treatment was performed at ℃ for 22 hours. Regarding the heat-treated adhesives obtained in each of the above Examples and Comparative Examples, the peel force and remaining rubber area (area where no peeling was observed between the rubber and adhesive) were determined by the JIS K-6301 90° peel test method. ) were measured respectively. The results obtained are shown in the following table.

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Claims (1)

[Scope of Claims] 1. The ratio of novolak type phenolic resin to 100 parts by weight of novolak type epoxy resin is 40 to 100 parts by weight, and the curing agent thereof is 5 to 30 parts by weight to the novolak type phenolic resin. A method of applying a vulcanizable adhesive composition to a metal, contacting it with unvulcanized fluorocarbon rubber, and vulcanizing it under pressure at the vulcanization temperature of the fluorocarbon rubber. Adhesion method with fluoro rubber. 2. Adhesion method according to claim 1, in which the vulcanized adhesive formulation is used in the form of an organic solvent solution. 3 A additive in which the novolak type phenolic resin is used in a ratio of 40 to 100 parts by weight to 100 parts by weight of the novolak type epoxy resin, and the curing agent thereof is used in a ratio of 5 to 30 parts by weight to the novolak type phenolic resin. A sulfur adhesive formulation is applied to the metal, subjected to a baking process, and then brought into contact with unvulcanized fluorocarbon rubber.
A method of bonding metal and fluoro rubber characterized by pressure vulcanization at the vulcanization temperature of fluoro rubber. 4. Adhesion method according to claim 3, in which the vulcanized adhesive formulation is used in the form of an organic solvent solution.