JPH05180344A - Gasket - Google Patents

Abstract

PURPOSE:To provide a gasket capable of keeping a preferable sealing for a long time because of excellent adhesiveness between a gasket main body layer and a silicone coating layer without disposing a primer layer and excellent in manufacturing efficiency. CONSTITUTION:A part or the whole of a gasket main body layer 1 is covered with a silicone coating layer 3 via an obverse layer 2, which is made of a composition including non-asbesto fiber, non-silicone rubber, a silicone denatured polymer and a filler. Consequently, the obverse layer 2 by itself is excellent in sealing performance, and the composition for forming the obverse layer 2 is excellent in workability such as roll warkability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gasket which has excellent manufacturing efficiency and is suitable for various industrial applications.

[0002]

2. Description of the Related Art Conventionally, a gasket having a silicone coating layer on the surface of a gasket body layer via a primer layer made of a thermoplastic resin has been known. The silicone coating layer is for preventing the formation of gaps and improving the gasket sealing performance, and the primer layer is for improving the adhesion between the silicone coating layer and the gasket body layer. is there.

However, when a thermoplastic resin such as polyvinyl butyral is dissolved in a solvent such as ethanol or MEK and the solution is screen-coated to form a primer layer, the solvent volatilizes during the coating work, and the screen is not visible. There is a problem in that workability such as clogging is poor, a large amount of energy and a long time are required for heating and drying the coating layer, and there is a problem that the manufacturing efficiency of the gasket is generally poor. Even if the workability of screen coating is improved by using a high boiling point solvent, the energy and time required for the drying process are further increased, and it is difficult to improve the production efficiency as a whole.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the need for forming a primer layer. That is, an object of the present invention is to obtain a gasket that has excellent adhesion between the gasket body layer and the silicone-based coating layer without providing a primer layer, maintains good sealing performance for a long time, and has excellent manufacturing efficiency.

[0005]

According to the present invention, a silicone-based coating layer is provided on a part or all of the surface of a gasket body layer via a surface layer, and the surface layer comprises a non-asbestos fiber and a non-silicone. The present invention provides a gasket characterized by comprising a composition comprising a system rubber, a silicone-modified polymer and a filler.

[0006]

The above composition is excellent in workability such as roll workability and is also excellent in adhesiveness with silicone-based substances and non-silicone-based substances. Therefore, by providing the surface layer made of such a composition, the gasket body layer and the silicone-based coating layer can be firmly adhered, the primer layer can be eliminated, and good sealing performance can be exhibited for a long period of time. .. Further, since the processing is easy, the surface layer can be efficiently formed, and the manufacturing efficiency of the gasket is generally excellent.

[0007]

Examples of Components of the Invention The gasket of the present invention has a silicone-based coating layer on a part or all of the surface of the gasket body layer via a surface layer. Any appropriate material may be used as the gasket body layer. Internal combustion engine,
In particular, any of various known gaskets used for automobile engines and the like can be used.

A gasket body layer that can be preferably used is one in which a sealing composition layer is provided on both sides of a hook stand metal plate. The gasket having the gasket body layer of the form according to FIG. 1 is illustrated. 1 is a gasket body layer, 11 is a sealing composition layer (vulcanization treatment), 12 is a hook 13
2 is a surface layer and 3 is a coating layer.

As the sealing composition for forming the gasket body layer, rubber components 3 to 2 as a binder are used.
0% by weight, fiber component 1 to 30% by weight, filler 20 to 80
Those containing a rubber chemical in an appropriate amount by weight% and, if necessary, a water-absorbent resin are preferably used in view of sealing performance and mechanical strength. The composition for sealing can be prepared by using one kind or two or more kinds of the compounding ingredients and appropriately mixing them with various kneaders to form a compound.

Examples of the rubber component include natural rubber, styrene / butadiene rubber, acrylonitrile / butadiene rubber, acrylic rubber, chloroprene rubber, fluororubber, epichlorohydrido rubber, chlorosulfonated polyethylene rubber, chlorinated polyethylene rubber, ethylene. -Synthetic rubber such as propylene rubber and ethylene / propylene / diene rubber can be used.

As the fiber component, non-asbestos fibers are preferably used from the viewpoint of environmental hygiene and one or more kinds of organic fibers or non-asbestos inorganic fibers are used. Examples of the organic fiber include aromatic polyamide fiber, phenol resin fiber, fluororesin fiber, aromatic polyester fiber, aromatic polyimide fiber, aromatic polybenzimidazole fiber, cellulose fiber, carbon fiber and the like. Above all, those having excellent heat resistance are preferable. The thickness is 1 to 50 μm, especially 5 to 35 μm, and the aspect ratio is 10
Approximately 1000, and especially approximately 20 to 500 are preferably used.

Examples of the non-asbestos inorganic fibers are silica fibers, zirconia fibers, rock wool, alumina fibers, alumina silicate fibers, phosphate fibers, sepiolite fibers, gypsum fibers, potassium titanate fibers, glass fibers, metal fibers and the like. Can be given. Thickness is 1 to 50
A film having an aspect ratio of about 20 to 700 in μm is preferably used. The proportion of non-asbestos-based inorganic fibers used is
0 (unused) to 2000 parts by weight, and especially 50 to 1500 parts by weight are preferable per 100 parts by weight of the organic fiber.

Examples of the filler include talc, clay, calcium carbonate, barium sulfate, mica, silica, carbon black, alumina, vermiculite, activated clay and acid clay.

As the rubber chemicals, those usually blended in the formation of the gasket are appropriately used. Examples thereof include vulcanizing agents, vulcanization aids, vulcanization accelerators, antioxidants, pigments or colorants, coupling agents and the like.

The water-absorbent resin, which is blended as necessary, is
The purpose is to improve water sealability due to swelling due to water absorption. The content is suitably 20% by weight or less. The water-absorbent resin used may be insoluble in water that absorbs water and swells. Examples thereof include an ionizable group such as a carboxyl group, a sulfone group, a phosphoric acid group, a quaternary ammonium salt group, an amino group and a pyridinium group or a salt thereof, and / or a hydroxyl group, an ether group, a chain or cyclic amide group. , Natural or synthetic hydrophilic and water-insoluble polymer substances containing a nonionic hydrophilic group such as a nitrile group.

More specifically, for example, a copolymer of acrylic acid or a salt thereof and divinylbenzene, an alkali hydrolyzate of a copolymer of acrylonitrile, vinyl chloride and an ethylene monomer, acrylonitrile, vinylidene chloride and an ethylene type. Alkaline hydrolyzate of copolymer with monomer, formaldehyde cross-linked product of acrylamide copolymer, acid condensate of polyacrylic acid and polyvinyl alcohol, epichlorohydrin cross-linked product of polyvinyl alcohol, alkali hydrolyzate of acrylonitrile-based polymer Examples thereof include formaldehyde cross-linked products and polyvinyl alcohol phosphoric acid condensates.

Further, a copolymer of 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate, a copolymer of 2-methyl-5-vinylpyridine and N, N'-methylenebisacrylamide, N, N'-dimethyl. A copolymer of aminoethyl methacrylate and N, N'-methylenebisacrylamide, a copolymer of N-vinyl-2-pyrrolidone and ethylene glycol dimethacrylate, radiation-crosslinked polyoxyethylene, and starch under acidic conditions. Heat condensate, saponified starch / acrylonitrile graft copolymer, saponified vinyl ester / ester unsaturated carboxylic acid or its derivative (dry product), isobutylene / maleic acid copolymer, etc. Be done.

The surface layer provided on a part or all of the surface of the gasket body layer is formed of a composition having a sealing property, which contains non-asbestos fibers, non-silicone rubber, silicone modified polymer and a filler. The surface layer composition that can be preferably used in terms of sealing performance, interlayer adhesion, mechanical strength, and the like is 3 to 20% by weight of a binder component composed of a non-silicone rubber and a silicone-modified polymer, 1 to 30% by weight of a fiber component, and The agent contains 40 to 90% by weight and an appropriate amount of a rubber chemical. Such a composition can be prepared by using one or two or more of the respective components and appropriately mixing them with various kneaders to form a compound.

The ratio of the non-silicone rubber and the silicone-modified polymer used as the binder is 9 based on the former / the latter in view of the adhesion between the layers and the workability such as roll work.
9/1 to 90/10 are suitable. Examples of the non-silicone rubber that can be used include those exemplified in the above-mentioned sealing composition for forming the gasket body layer. Examples of silicone-modified polymers include polyolefin-modified silicone elastomers and silicone-modified acrylic polymers.

The above-mentioned polyolefin-modified silicone elastomer is, for example, a polyorganosiloxane obtained by reacting a polyolefin such as polyethylene, linear low-density polyethylene, ethylene / vinyl acetate, ethylene / ethyl acrylate, etc. It has a composition of a phase, a discontinuous phase (mesh structure) composed of silicone rubber (crosslinked product) and a polyolefin-silicone copolymer, and a compatibilized phase composed of a silicone-polyolefin graft compound. Such a polyolefin-modified silicone elastomer is commercially available, for example, under the trade name of Silgraft (manufactured by Nippon Unicar Co., Ltd.). On the other hand, the silicone-modified acrylic polymer is commercially available, for example, under the trade name: SX800 (A) -01 (manufactured by Japan Synthetic Rubber Co., Ltd.).

Examples of the fiber component, the filler, and the appropriate amount of rubber chemicals used for the preparation of the surface layer composition include those exemplified for the above-mentioned sealing composition for forming the gasket body layer. The proportion of the non-asbestos inorganic fiber used in the surface layer composition is preferably 0 to 50 parts by weight, and more preferably 1 to 30 parts by weight, per 100 parts by weight of the organic fiber.
The surface layer is formed by rubbing into the gasket body layer,
It can be performed by an appropriate method such as a method of forming the composition into a sheet and adhering it to a sheet.

The silicone coating layer provided on the surface layer is formed of silicone rubber. As the silicone-based rubber, any conventionally used silicone-based rubber such as room temperature or thermosetting type of addition type or condensation type can be used. As a specific example, CY5
2-237 (manufactured by Toray Dow Corning), X32-11
34, KE-1083 (all manufactured by Shin-Etsu Chemical Co., Ltd.) and the like.

In the manufacture of the gasket of the present invention, an unvulcanized sealing composition is formed on both sides of a support base made of, for example, a hook stand metal plate by a calendering method with a predetermined thickness using a calender roll or the like. After that, a layer of the composition in the unvulcanized state for the surface layer is formed thereon by a rubbing method or a sheet lamination method, and then they are heated to form a sealing composition layer and a surface layer composition layer. It can be carried out by a method of vulcanizing and then forming a silicone-based coating layer on the surface layer. When using a hook stand metal plate, it is preferable to squeeze the hook and hold the sealing composition layer or the surface composition layer with the hook.

In the gasket of the present invention, the surface layer may be formed on the entire surface of the gasket body layer,
It may be only the place where the silicone coating layer is provided. In that case, the gasket body layer may be, for example, one that has been punched into a predetermined shape in advance so as to fit the engine structure to which it is applied. The thickness of the surface layer to be formed may be appropriately determined, but is usually 0.05 to 0.5 mm,
Especially, it is 0.1 to 0.3 mm. The thickness of the sealing composition layer is not limited, but is usually 0.1 to 1.0 m.
m, especially 0.2 to 0.8 mm. The thickness of the supporting base such as a hook stand metal plate (excluding the hook portion) is not limited, but is usually 0.05 to 1.0 mm, especially 0.
It is 1 to 0.5 mm.

The silicone-based coating layer is formed by applying a silicone-based rubber or its diluting liquid onto the surface layer by an appropriate method such as a screen coating method, a roll coating method, a curtain coating method, a dispenser method and the like. It can be performed by curing treatment. In addition, in forming the coating layer, an appropriate additive or drug can be added to the silicone rubber in a conventional manner. The thickness of the silicone-based coating layer to be formed is arbitrary, but generally 10 to 500 μm, especially 50 to 2
It is 00 μm. The position where the silicone-based coating layer is formed on the gasket body layer can be appropriately determined according to the conventional method.

The gasket of the present invention can be used in various applications such as industrial applications such as automobile engines. In particular, it is advantageously used for applications exposed to high temperature and high pressure such as cylinder head gaskets in internal combustion engines, and applications involving water and the like.

[0027]

According to the present invention, it is possible to obtain a gasket in which the gasket body layer and the silicone-based coating layer are firmly adhered to each other via the surface layer which is excellent in sealing performance. As a result, the formation of the primer layer, which requires a lot of labor for the treatment, can be eliminated. Moreover, since the composition for forming the surface layer is excellent in workability such as roll workability, a gasket having good sealing performance for a long period of time and excellent manufacturing efficiency can be obtained.

[0028]

【Example】

Example 1 NBR (trade name: Perbunan 2818, manufactured by Bayer)
8 parts as a solid content (weight part, the same hereinafter), 5 parts of organic fiber (trade name: Kynol, manufactured by Gunei Chemical Co., Ltd.), clay (trade name: Soft Neo Carrier K, manufactured by Asada Flour Milling Co.) 40.9
Department, Talc (Product name: Talc SW, manufactured by Nippon Talc Co., Ltd.) 4
0 parts, red iron oxide 5 parts, vulcanizing agent (trade name: DCP40C,
Mitsui Petrochemical Industry Co., Ltd. 0.5 part and vulcanizing agent (trade name:
A mixture consisting of 0.1 part of Perkalink 400, manufactured by Kayaku Akzo Co., Ltd. was rubbed with calender rolls on both sides of an iron plate with a hook having a thickness of 0.25 mm to obtain a gasket main body layer, and then the above mixture was placed thereon. In accordance with the above, a surface layer composition in which 0.5 part of a polyolefin-modified silicone elastomer (trade name: Silgraft-150, manufactured by Nihon Unicar Co., Ltd.) was additionally blended was rubbed according to the above, and vulcanized by heating at 150 ° C. After that, a condensation type silicone rubber coating agent (trade name: KE-1081, manufactured by Shin-Etsu Chemical Co., Ltd.) is screen-coated on one surface of the surface layer, and heated at 80 ° C. for 10 minutes and then at 150 ° C. for 15 minutes to have a thickness of 70 μm. A coating layer was formed to obtain a gasket having a thickness of 1.25 mm.

Example 2 NBR (trade name: Nippon LX513, manufactured by Zeon Corporation) 8 parts as solid content, inorganic fiber (trade name: CMF-1)
50 parts, manufactured by Nippon Cement Co., Ltd., 3 parts Kynol, clay (trade name: Translink Clay 37, manufactured by Engelhard Co., Ltd.) 30 parts, talc SW; 40 parts, red iron oxide 5 parts,
Example 1 using a mixture of 10.3 parts of acid clay, 0.6 part of DCP40C, 0.1 part of PARCALINK 400, and a surface layer composition in which Silgraft-150; 1.0 part was additionally compounded. A gasket was obtained according to.

Example 3 Perbunan 2818; 8 parts as solids, CMF-15
0; 10 parts, Kynol 3 parts, Soft Neo Carrier K;
40 parts, talc SW; 32.9 parts, red iron oxide 5 parts, DC
P40C; 0.5 part, Percalink 400; 0.1 part mixture, and a composition for the surface layer additionally compounded with 0.5 part of a polyolefin-modified silicone elastomer (trade name: Silgraft-310, manufactured by Nippon Unicar Co., Ltd.) A gasket was obtained in the same manner as in Example 1 using.

Example 4 Perbunan 2818; 6 parts as solids, Kynol 5
Part, Translink clay 37; 40.3 parts, Talc S
W: 40 parts, red iron oxide 5 parts, DCP40C: 0.6 part,
PARKALINK 400; a mixture consisting of 0.1 part, and a silicone-modified acrylic polymer (trade name: SX
A gasket was obtained according to Example 1 using a surface layer composition additionally containing 3 parts of 800 (A) -01, manufactured by Japan Synthetic Rubber Co., Ltd.).

Example 5 Nippon LX513; 4 parts as solid content, CMF-1
50; 4 parts, Kynol 2 parts, Translink clay 3
7; 30 parts, talc SW; 39 parts, red iron oxide 5 parts, acid clay 10.3 parts, DCP40C; 0.6 parts, Parkerlink 400; 0.1 part mixture, and SX8
00 (A) -01; a gasket was obtained in the same manner as in Example 1 except that the surface layer composition additionally containing 5 parts was used.

Example 6 Perbunane 2818; 8 parts as solids, Kynol 5
Part, Soft Neo Carrier K; 40.3 parts, Talc SW;
35 parts, water absorbent resin (Brand name: Aquaric CAM
L-20, manufactured by Nippon Shokubai Co., Ltd.) 5 parts, red iron oxide 5 parts, DCP
40C; 0.6 part, Percalink 400; a mixture of 0.1 parts, and a surface layer composition containing Silgraft-310; 1.0 part in place of the water-absorbent resin. , Got the gasket.

Example 7 Nippon LX513; 8 parts as solid content, CMF-1
50; 3 parts, Kynol 3 parts, Soft Neo Carrier K;
30 parts, talc SW; 30 parts, water absorbent resin (trade name:
Sumikagel NP-1010, Sumitomo Chemical Co., Ltd.) 10 parts, red iron oxide 5 parts, acid clay 4.9 parts, silica (trade name: Microsilica SF powder, Nippon Heavy Chemical Industry Co., Ltd.) 5 parts,
DCP40C; 0.5 part, Parkerlink 400; 0.1
A gasket was obtained in the same manner as in Example 1 except that the surface layer composition containing 0.5 part of Silgraft-150;

Comparative Example 1 Perbunan 2818; 10 parts as solid content, Kynol 5 parts, Translink clay 37; 30 parts, Talc S
W: 10 parts, red iron oxide 4.5 parts, acid clay 39.5 parts,
Vulcanizing agent (sulfur, Hosoi Chemical Co., Ltd.) 0.05 parts, vulcanization accelerator (trade name: Nocceller TT, Ouchi Shinko Chemical Co., Ltd.)
A gasket body layer was formed using a mixture of 0.45 part and zinc flower (No. 3, manufactured by Sakai Chemical Industry Co., Ltd.) of 0.5 part, and then a silicone-based coating layer was directly formed according to Example 1. Got a gasket.

Comparative Example 2 Perbunane 2818; 5 parts as solids, Kynol 5
Part, Translink clay 37; 30.5 parts, talc S
W: 10 parts, red iron oxide 4.5 parts, acid clay 39.5 parts,
A mixture of 0.025 parts of sulfur, 0.225 parts of Nocceller TT; 0.25 parts of zinc white, and 4.8 parts of a silicone polymer (trade name: KR2706, manufactured by Shin-Etsu Chemical Co., Ltd.) and a silicone polymer. (Product name: C2
706, manufactured by Shin-Etsu Chemical Co., Ltd.). A gasket was obtained in the same manner as in Example 1 except that 0.2 parts of the surface layer composition was additionally compounded.

Comparative Example 3 Nippon LX513; 8 parts as solid content, CMF-1
50; 2 parts, Kynol 3 parts, Soft Neo Carrier K;
20 parts, talc SW; 6.4 parts, red iron oxide 5 parts, acid clay 50 parts, microsilica SF powder; 5 parts, DCP
After forming a gasket main body layer using a mixture of 40C; 0.5 part and Percalink 400; 0.1 part,
A silicone-based coating layer was directly formed on it according to Example 1 to obtain a gasket.

Evaluation Test Workability The workability in forming the seal layer and the surface layer in the calender roll processing before forming the silicone-based coating layer was examined and evaluated according to the following criteria. ◯: Good workability was exhibited, and in the case where the seal layer and the surface layer were formed, the overlapping layer could be formed with a uniform layer thickness. X: When the workability was poor and it was difficult to superimpose the surface layer on the seal layer with uniform layer thickness.

Adhesive Strength The silicone-based coating layers of the gaskets obtained in Examples and Comparative Examples were erased (JIS 583080 plastic
Rubbing with eraser) and the number of rubbing until the coating layer was peeled off was examined.

The above results are shown in Table 1.

[Table 1]

[Brief description of drawings]

FIG. 1 is a sectional view of an example.

[Explanation of symbols]

 1: Gasket body layer 11: Composition layer for sealing 12: Metal plate 13: Hook 2: Surface layer 3: Silicone coating layer

Claims (1)

[Claims] 1. A gasket coating comprising a silicone-based coating layer on a part or all of the surface of a gasket body layer, with the surface layer being filled with non-asbestos fibers, non-silicone rubber, and silicone-modified polymer. A gasket comprising a composition containing an agent.