JPS61207477A - Adhesive composition for vulcanization and method of bonding using same - Google Patents

Abstract

PURPOSE:To obtain an adhesive composition for vulcanization useful for bonding between a metal and a silicone rubber, by adding a specific organic silane compound to a novolak phenol resin and a curing agent comprising hexamethylenetetramine. CONSTITUTION:The titled composition is prepared by adding about 0.5-5pts.wt. at least one member selected from a vinyltrialkoxysilane and a alpha- aminopropyltrialkoxysilane to each of 100pts.wt. novolak phenol resin and 5-20pts.wt. curing agent comprising hexamethylenetetramine. The composition is generally used in the form of an organic solvent solution thereof. The composition is used for bonding between a metal and a silicone rubber as follows. The composition is applied on a metal and subjected to baking treatment. An unvulcanized composition of a silicone rubber is bonded thereto and vulcanization under pressure is conducted at a temperature suitable for vulcanization of a silicone rubber.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to vulcanized adhesive formulations and adhesive methods using the same. More specifically, the present invention relates to a vulcanized adhesive compound that is effectively used for bonding surfaces between metal and silicone rubber, and a bonding method using the same.

[Prior Art] and [Problems to be Solved by the Invention] Conventionally, organic silane-based adhesives have been used to bond metals and silicone rubber, but when this adhesive is used, The outside environment causes rust on the surface of metal, especially steel plates, which causes adhesive to leak.

The present inventors have conducted various studies in search of a vulcanized adhesive formulation for this type of use that suppresses rusting that causes adhesive failure and has excellent peeling strength. It has been found that the above problems can be effectively solved by adding a specific organic silane compound to the tetramine curing agent.

SUMMARY OF THE INVENTION Accordingly, the present invention relates to a vulcanizable adhesive formulation comprising a novolac type phenolic resin and a hexamethylenetetramine cured mK.

At least one of vinyltrialkoxysilane and r-aminopropyltrialkoxysilane is added.

The present invention also relates to a method of adhering metal and silicone rubber using such a vulcanized adhesive composition, wherein the adhesion between metal and silicone rubber is performed by applying the above-mentioned vulcanized adhesive composition onto the metal;
After the baking treatment, an unvulcanized silicone rubber compound is bonded thereto and pressure vulcanized at the vulcanization temperature of silicone rubber.

Novolak type phenol resin is a soluble phenol-formaldehyde resin obtained by condensing phenol and formaldehyde using an acid as a catalyst, and in the present invention, its melting point (softening temperature) is about 100°C. At the front and back, the molecular weight is 'Ilt, about 100 to several thousand 2.
Stage process phenolic resins are commonly used. Novolak molecules do not have reactive groups (methylol groups), so simply heating will not cause intermolecular condensation and will maintain thermoplasticity permanently, but formaldehyde is used as a source of methylene groups for curing. Alternatively, when hexamethylenetetramine is added and heated, it becomes insoluble and infusible.

The vulcanizable adhesive formulation according to the present invention comprises a commonly used vinyl trichloride in a proportion of about 0.5 to 5 parts by weight, respectively, to 100 parts by weight of a novolac-type phenolic resin and about 5 to 20 parts by weight of a hexamethylenetetramine curing agent. It is prepared by adding at least one of alkoxysilane and r-aminopropyltrialkoxysilane. In these organic silane compounds, the alkoxy group is preferably an ethoxy group.

A compound consisting of the above ingredients is generally prepared and used in the form of an organic solvent solution. Any organic solvent can be used as long as it can dissolve these components, but methanol, ethanol, etc. are particularly preferred. The organic solvent solution is about 0.5 to 1
The solids concentration is adjusted to 5%, preferably within the range of about 3-7%.

When the vulcanized adhesive formulation solution prepared in this way is used for bonding metal and silicone rubber, this solution is applied onto the metal, such as a mild steel plate, and the After heating and drying to about ℃, the temperature is generally about 180℃.
Baking treatment is carried out by heating at ~210°C for approximately 5 to 30 minutes, and an unvulcanized silicone rubber compound is bonded thereto, and the mixture is heated to approximately 160 to 20°C, which is the vulcanization temperature of silicone rubber, using a mold or the like.
Bonding is performed by heating to 0° C. and vulcanizing under pressure.

Unvulcanized formulations of silicone rubber to be bonded are generally prepared by adding fillers and vulcanizing agents to organopolysiloxane raw rubbers, such as reinforcing silica-based fillers, and vulcanized fillers. Organic peroxides are generally used as sulfur agents.

〔Effect of the invention〕

When the vulcanized adhesive composition according to the present invention is used for adhering metal and silicone rubber, etc., no rust is observed on the metal surface in an open air environment, and therefore, the adhesive composition does not cause rusting. This phenomenon is not observed and a stable adhesion effect can always be obtained.

The vulcanized adhesive composition of the present invention, which exhibits such effects, can be applied as an adhesive between metal and silicone rubber, for example, to engine seals, cylinder head gaskets, oil seals in high-temperature atmospheres, etc. It can be used effectively.

〔Example〕

Next, the present invention will be described with reference to one embodiment.

Example 1 Novolac type phenol resin (melting point 100°C) 100 parts by weight Hexamethylenetetramine 10 Vinyltriethoxysilane I! -aminopropyltriethoxysilane 1 methanol
2240 A solution vulcanized adhesive formulation consisting of a mixture of the above components was applied onto a mild steel plate whose surface had been roughened to about 10-15 μm by shot blasting.

Thereafter, it was dried at 50°C for 10 minutes, then baked at 200°C for 10 minutes, and the baked metal plate was left in an atmosphere of 30°C and 85% relative humidity for 1 or 3 days.

On this metal plate, add 100 f of organopolysiloxane raw rubber.
s, 50 parts of reinforcing silica-based filler, and 2 parts of di-tert-butylperoxyhexane. TIS K-6301,90
＠Join according to the peel test method and use a mold to
℃ for 4 minutes, and then the vulcanized adhesive was
Heat treatment was performed at 75°C for 5 hours.

Example 2 In Example 1, a solution vulcanizable adhesive formulation was prepared using 2 parts by weight of vinyltriethoxysilane without r-aminopropyltriethoxysilane.

Example 3 In Example 1, a solution vulcanizable adhesive formulation was prepared using 2 parts by weight of 1-aminopropyltriethoxysilane without t-vinyltriethoxysilane.

Comparative Example Commercially available organic silane-containing adhesive (Nippon Unicar product AP1
33), coating and vulcanization adhesion to a mild steel plate were performed in the same manner as in Example 1.

Regarding the vulcanized adhesives of adhesive-coated metal plates and silicone rubber obtained in each of the above examples and comparative examples,
The peeling force was measured using the peel test method described above, the area ratio of the rubber remaining after peeling was measured, and the state of rust was also observed. The results obtained are shown in the following table.

table

Claims (1)

[Scope of Claims] 1. A vulcanized adhesive composition comprising a novolac type phenolic resin and a hexamethylenetetramine curing agent, and at least one of vinyltrialkoxysilane and γ-aminopropyltrialkoxysilane. 2. Claim 1 prepared in the form of an organic solvent solution
Vulcanized adhesive formulations as described in Section. 3. Applying a vulcanized adhesive composition consisting of a novolak type phenol resin and a hexamethylenetetramine curing agent to which at least one of vinyltrialkoxysilane and γ-aminopropyltrialkoxysilane is added onto the metal, and baking treatment. A method for adhering metal and silicone rubber, which comprises bonding an unvulcanized mixture of silicone rubber thereto and vulcanizing it under pressure at the vulcanization temperature of silicone rubber. 4. Adhesion method according to claim 3, in which the vulcanized adhesive formulation is used in the form of an organic solvent solution.