JPH07233873A - Sheet for metal gasket and coating agent therefor - Google Patents

Abstract

PURPOSE:To obtain a sheet for metal gasket and a coating agent which develop the excellent sealing performance with good balance for gas, water or/and oil and develop the high performance sealing function even for an internal combustion engine which secures the power economization and reduction of weight in the low total tightened quantity and thin deformable type constitution. CONSTITUTION:A sheet for a metal gasket which has a coating layer 2 consisting of a vulcanized rubber layer containing a water absorptive resin or/and an oil absorptive resin at least on one-sided surface of a metal core member 1, and a coating agent for the metal core member for gasket which is formed by compounding 10-100 pts.wt. of the water absorptive resin or/and oil absorptive resin into 100 pts.wt. of the vulcanization type rubber composition are provided. These substances possess the excellent mechanical strength, durability, and manufacturing efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal gasket sheet which exhibits excellent sealing performance against gas, water and oil and is suitable for forming various industrial gaskets for automobiles and the like, and a coating agent therefor. .

[0002]

2. Description of the Related Art Conventionally, as a cylinder head gasket, one having a coating layer of fluororubber provided on one side or both sides of a metal core material composed of a single plate or a laminated plate has been known. The cylinder head gasket is intended to seal between the cylinder head and the cylinder block of the internal combustion engine, and exhibits sealing performance against cooling water and lubricating oil in addition to high pressure combustion gas generated in the cylinder. Is required. By the way, for automobiles, performances such as heat resistance, LLC (Long Life Coolant) resistance, oil and water resistance, and high strength are required.

However, the conventional cylinder head gasket has a problem that it cannot sufficiently cope with the recent labor-saving and lightweight internal combustion engine. That is, in recent years, internal combustion engines have been designed to reduce the number of tightening holes for the purpose of labor saving in the hole drilling process and the assembly process, and to reduce the wall thickness for the purpose of weight reduction. It is required that the desired sealing performance is exhibited even with a small tightening surface pressure and a larger deformation than before, but the conventional cylinder head gasket has a well-balanced sealing performance against gas and water or / and oil. However, it is difficult to form such products, and it is not possible to meet such demands.

Incidentally, in the case where the cylinder head and the cylinder flock are tightened with high surface pressure and high rigidity by giving priority to the gas seal, the number of tightening holes and the thickness of the tightening holes are relatively large with respect to the sealing portion of the cooling water or the lubricating oil. It becomes necessary to reduce the distribution of thickness, which leads to a decrease in tightening surface pressure and a large deformation, resulting in a reduction in sealing conditions, and it is necessary to cover the decrease with improved gasket performance.

[0005]

SUMMARY OF THE INVENTION The present invention provides a well-balanced sealing performance against gas, water and / or oil, and therefore, the above-mentioned labor-saving and lightweight internal combustion engine,
In other words, it is an object to develop a metal gasket sheet that exhibits a high-performance sealing function even for an internal combustion engine of a low tightening amount and a thin and easily deformable type.

[0006]

According to the present invention, a metal gasket having a coating layer made of a vulcanized rubber layer containing a water-absorbent resin or / and an oil-absorbent resin is provided on at least one surface of a metal core material. A sheet, and a coating agent for a metal core material for a gasket, comprising 100 parts by weight of a vulcanizable rubber composition and 10 to 100 parts by weight of a water-absorbent resin or / and an oil-absorbent resin. It is a thing.

[0007]

With the above structure, a metal gasket sheet which is excellent in strength and thinness based on the metal core material and is free from harmful fibers such as asbestos can be easily obtained, and a water-absorbent resin or / and oil-absorbent resin can be obtained. Absorbs water and / or swells oil based on a vulcanized rubber-based coating layer containing a water-soluble resin, and exhibits excellent sealing performance against water or oil due to its volume expansion, and protects against gas and water or / and oil. The advanced sealing function lasts for a long time.

[0008]

Examples of Embodiments The metal gasket sheet of the present invention has a coating layer composed of a vulcanized rubber layer containing a water-absorbent resin and / or an oil-absorbent resin on one or both sides of a metal core material. I will do it. Examples thereof are shown in FIGS. 1 and 2. Reference numeral 1 is a metal core material, and 2 is a coating layer. In the present invention, the fiber-free coating layer may be a fiber-free metal gasket sheet.

As the metal core material, a flat single plate or a laminated plate,
Appropriate ones such as those partially folded back by pressing or the like and those subjected to beading may be used. The thickness may be appropriately determined according to the purpose of specification, but from the viewpoint of thinning and strength, 50 μm to 1 mm, especially 100 to 800 μm, especially 200 to
500 μm is preferred. The material may be appropriately determined, for example, iron-based metals such as steel, iron, zinc-plated iron, tin-plated iron, copper-based metals such as copper and brass, aluminum-based metals such as aluminum and its alloys, and other stainless steels. Examples include high strength metals.

The coating layer is formed as a vulcanized rubber layer containing a water-absorbent resin and / or an oil-absorbent resin. The coating agent preferably used for forming the coating layer is 100 parts by weight of the vulcanizable rubber composition, and the total amount of the water-absorbent resin or / and the oil-absorbent resin is 10 to 1
00 parts by weight, especially 15 to 90 parts by weight, especially 20 to 80 parts by weight.

When the total amount of the water-absorbent resin and / or the oil-absorbent resin is less than 10 parts by weight, the swelling degree due to water absorption and / or oil absorption is poor and the effect of increasing the film thickness of the coating layer is not sufficient. When it exceeds the weight part, the rubber elasticity is lowered, and in any case, it is difficult to balance the sealing performance against gas and water or / and oil.

Examples of the vulcanizable rubber composition include suitable rubbers such as (hydrogenated) acrylonitrile-butadiene rubber, fluororubber, acrylic rubber, epichlorohydrin rubber, natural rubber, styrene-butadiene rubber and silicone rubber. Known substances include vulcanizing agents, vulcanization aids, and vulcanization accelerators, if necessary, for vulcanization treatment. When exposed to a high temperature atmosphere like a cylinder head gasket, fluororubber is preferably used as the rubber component.

As the water-absorbent resin, various resins which are insoluble in water and absorb water to swell can be used. 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, an imino group and a pyridinium group, or a salt thereof, and / or a hydroxyl group, an ether group, a chain or a cyclic group. Amide group of
Examples thereof include natural or synthetic hydrophilic and water-insoluble polymer substances containing a nonionic hydrophilic group such as a nitrile group.

Specific examples of the polymer substance include acrylic acid or a salt thereof, a copolymer thereof with divinylbenzene, an alkaline hydrolyzate of a copolymer of acrylonitrile, vinyl chloride and an ethylene monomer, acrylonitrile and chloride. Alkaline hydrolysates of copolymers of vinylidene and ethylene-based monomers, formaldehyde cross-linked products of acrylamide-based copolymers, acid condensates of polyacrylic acid and polyvinyl alcohol, epichlorohydrin cross-linked products of polyvinyl alcohol, acrylonitrile-based polymers Examples thereof include formaldehyde cross-linked products of alkaline hydrolysates and phosphoric acid condensates of polyvinyl alcohol.

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. To be

As the oil-absorbent resin, one that absorbs oil and swells is used, and its type is not particularly limited. Examples thereof include polynorbornene rubber-based oil-absorbing resin, self-swelling acrylic polymer, and the like, and commercially available products include, for example, oleosorb (trade name, manufactured by Nippon Shokubai Kagaku Kogyo Co., Ltd.). Among them, a granular water slurry type (oleosorb SL-200), particularly an emulsion type (oleosorb EM-631) is preferably used.

The vulcanizable rubber composition is prepared by a method of mixing one or more kinds of respective compounding components with a solvent such as methyl ethyl ketone or methyl isobutyl ketone as necessary, or various kneading of the compounding components. It can be carried out by appropriately mixing by a mixing method using a machine or the like.

In preparing the vulcanizable rubber composition, if necessary, for example, carbon, talc, clay, barium sulfate, silica, mica, vermiculite, fillers such as calcium carbonate, calcium hydroxide, etc. Acid acceptor,
Conventional additives such as processing aids, antioxidants, pigments, colorants, coupling agents, scorch inhibitors, etc. can be added in usual amounts.

The sheet for metal gasket is formed by, for example, a method of applying a vulcanizable rubber composition having a solid content concentration of 20 to 50% by weight using a solvent by a suitable method, or a vulcanization method using a calendar roll or the like. A vulcanizable rubber composition on one side or both sides of the metal core material by an appropriate method such as a method of attaching or sliding in a rubber composition, or a method of forming a vulcanizable rubber composition into a sheet shape in advance and crimping the sheet. The coating layer can be attached, and the vulcanized rubber layer can be obtained by vulcanizing the coating layer under heating.

The thickness of the coating layer composed of the vulcanized rubber layer to be formed may be appropriately determined according to the purpose of use, but is generally 500 μm or less, preferably 5 to 200 μm in view of thinness and the like.
m, especially 10 to 100 μm. When the coating layer is attached, the metal core material may be previously coated with an appropriate adhesive such as an acrylonitrile rubber / phenol resin solution or a coupling agent such as a silane coupling agent to improve the adhesion.

The metal gasket sheet of the present invention is put to practical use in various industrial fields, for example, as a gasket used for a cylinder head or its periphery in an internal combustion engine such as an automobile engine, or in various forms combined with other materials. Can be used for The gasket is illustrated in FIGS. 3 to 5.

The gasket illustrated in FIG. 3 is for a cylinder head. This is performed by punching the metal gasket sheet of the present invention by a punching method to form a bore hole 31 corresponding to the opening shape of the cylinder top, a bolt insertion hole 32 for fixing the cylinder head to the cylinder block, and cooling water or lubrication. After the oil passage hole 33 is provided, the grommet 5 is attached to the bore hole portion.

In the gasket illustrated in FIG. 4, the metal gasket sheet (1, 2) of the present invention and the metal base material 4 having the projection 41 at the end are integrated by the grommet 5, and the vulcanized rubber The auxiliary seal portion 6 is provided.
This is intended to improve the sealing performance by adding the metal base material 4, and the metal base material (4) is usually made of the same or different metal as the metal core material and has a thickness of 1 mm. ~ 3
About twice as many are used.

The gasket illustrated in FIG. 5 is one in which the metal gasket sheets (1, 2) of the present invention are adhesively laminated on both sides of the metal base material 7. This can be formed, for example, by arranging the metal gasket sheet before vulcanization treatment on both sides of the metal base material 7 with an adhesive layer interposed therebetween, and heating under pressure to simultaneously perform vulcanization treatment and adhesion treatment. You can In the gasket of such a form, the metal layer is dispersed in the thin metal core material or the metal base material as compared with the case where one thick metal core material is used, the flexibility is increased by the dispersion effect, and the sealing performance is improved. It has advantages such as improved production and continuous production.
The metal base material (7) is usually made of the same or different metal as the metal core material and has a thickness of about 100 to 1000 μm.

[0025]

【Example】

Example 1 Fluorine rubber (E60C, containing vulcanizing agent, manufactured by DuPont) 1
00 parts (parts by weight, solid content, the same below), magnesium oxide (vulcanization aid) 3 parts, calcium hydroxide 6 parts, MT carbon (Thermax N990, manufactured by CanCarb Limited)
10 parts, and water-absorbent resin (Aqualic CA ML-
20, 20 parts manufactured by Nippon Shokubai Kagaku Kogyo Co., Ltd.) is mixed with methyl ethyl ketone to prepare a 25 wt% mixed liquid, which is applied to a stainless steel core material having a thickness of 200 μm,
After drying, it was vulcanized to obtain a metal gasket sheet having a coating layer with a thickness of 20 μm on both sides.

Example 2 Instead of a water-absorbent resin, an oil-absorbent resin (oleosorb) was used.
A metal gasket sheet was obtained in the same manner as in Example 1 except that 20 parts of SL-200 (the same applies hereinafter) was used.

Example 3 A metal gasket sheet was obtained in the same manner as in Example 1 except that 20 parts of the oil-absorbent resin was additionally compounded.

Comparative Example A sheet for metal gasket was obtained according to Example 1 except that a coating layer containing no water-absorbent resin was used.

Evaluation Test The following characteristics of the metal gasket sheets obtained in Examples and Comparative Examples were examined. Thickness change 100 ℃ cooling water (water + ethylene glycol etc.) or 1
The test piece was immersed in JIS No. 3 oil at 50 ° C. for 70 hours, and the change in thickness of the coating layer before and after the immersion was determined.

Sealing property A donut-shaped metal gasket sheet with a bead processing is set at a position with an outer diameter of 75 mm, an inner diameter of 55 mm, and a diameter of 57.1 mm in a test device conforming to the sealing property test of ASTM-F37, and the total is set. Tighten with a pressure of 150 kg (linear pressure 8.4 kg / cm ² ) to increase the internal water pressure or hydraulic pressure from 0.5 kg in 0.5 kg steps, and keep each rising pressure for 15 minutes to prevent water leakage or oil leakage. The internal pressure at which leakage occurred (confirmed visually) was examined. The test is the one that has been subjected to the above-mentioned immersion treatment,
And the one before immersion treatment (normal product). The water used for the sealability test is the cooling water described above, and the oil is JIS
It is No. 3 oil.

The above results are shown in Table 1.

[Table 1]

[0032]

EFFECTS OF THE INVENTION According to the present invention, excellent mechanical strength and durability, well-balanced high sealing function against gas and water or / and oil, low total tightening amount, thin-wall easily deformable type labor-saving and lightweight It is possible to obtain a metal gasket sheet that has a high-performance sealing function for a long period of time even in a simplified internal combustion engine and is excellent in manufacturing efficiency.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an example of a metal gasket sheet.

FIG. 2 is a cross-sectional view of another embodiment of the metal gasket sheet.

FIG. 3 is a plan view of an example gasket.

FIG. 4 is a cross-sectional view of another gasket example.

FIG. 5 is a cross-sectional view of another gasket example.

[Explanation of symbols]

 1: Metal core material 2: Coating layer 3: Cylinder head gasket 31: Bore hole 33: Cooling water or lubricating oil through hole 4, 7: Metal base material 5: Grommet 6: Auxiliary seal layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location F16J 15/08 Q

Claims (3)

[Claims] 1. A sheet for a metal gasket, which has a coating layer made of a vulcanized rubber layer containing a water-absorbent resin and / or an oil-absorbent resin on at least one surface of a metal core material. 2. A cylinder head gasket comprising the metal gasket sheet according to claim 1, wherein fluororubber is used as a rubber component of the vulcanized rubber layer. 3. A coating agent for a metal core material for gaskets, which comprises 100 parts by weight of a vulcanizable rubber composition and 10 to 100 parts by weight of a water-absorbent resin and / or an oil-absorbent resin.