JPH08312786A - Gasket material - Google Patents

Abstract

PURPOSE: To improve attachment with a flange surface when a water seal is used by a method wherein the surface of a metallic sheet is coated with a layer of a compound containing base material fibers, a rubber material, and an inorganic filler, and the compound further contains a water swelling material. CONSTITUTION: A compound layer 1 containing a base material fibers formed of both compressive inorganic fibers except asbestos and compressive organic fibers, a rubber material, and an inorganic filler is caused to further contain a water swelling agent. The compound layer 1 having a so formed composition is applied on both surfaces of a SPC steel sheet 3 previously coated with a heat resistant adhesive 2. This constitution improves drape with a flange surface when a gasket material is used in a water seal and provides excellent water sealing ability even at a low pressure surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gasket material used as a base material for various gaskets, and more particularly to a gasket material suitable for water sealing.

[0002]

2. Description of the Related Art Conventionally, joint sheets, beater sheets, oil sheets and the like have been widely used as non-metallic gasket materials.

Among conventionally known semi-metal gasket materials, flat metal plates such as SPCC steel plate, aluminum plate and stainless steel plate are coated with a layer of synthetic rubber alone (hereinafter, referred to as There was rubber coating gasket material.

In addition, synthetic rubber alone is used instead of 60
A semi-metal gasket material (hereinafter, referred to as rubber / asbestos compound / coating gasket material) in which the surface of a metal plate is coated with a rubber / asbestos compound containing 80% by weight has been developed and used in recent years.

Furthermore, the applicant of the present invention has found that Japanese Patent Publication No. 6-8478.
In No. 5, "a surface of a metal plate is a compound layer containing a base fiber composed of both a compressible inorganic fiber other than asbestos and a compressible organic fiber, a rubber material, a rubber chemical, and an inorganic filler. Gasket material which is coated on. "

[0006]

In the conventional soft gasket material such as the non-metallic gasket material, (a) the mechanical strength is weak (tensile strength is low), and (b) the pressure resistance is low (particularly the seal width). (C) is narrow), (c) is easily worn (torque reduction is large), (d) embossing cannot be performed, and it is difficult to increase surface pressure. (E) Assembly workability is poor (automatic assembly is performed). Difficult), etc.

Particularly, in recent years, as the weight of the engine has been reduced, the flange rigidity of the engine has decreased, and along with this, the deformation at the time of tightening the flange and the thermal deformation tend to increase. Therefore, when the conventional non-metallic gasket material is mounted on an engine, "breakage" or torque reduction exceeding the compression elastic limit is increased. Further, the decrease in heat resistance and the decrease in mechanical strength of joint sheets, beater sheets, etc. due to the non-asbestos gasket materials in recent years tend to further increase these problems.

On the other hand, the rubber coating gasket material has various advantages as follows.

(A) Embossing is possible, (B) Since the base material is a metal plate, it has high strength, and even in a narrow gasket width, the gasket does not cut and blows through. (C) Asbestos Since it is not a fibrous structure like a joint sheet, there is no substance leakage or oozing out from the gasket itself, (D) excellent torque retention, very little torque reduction, (E) good thickness accuracy, (F) mold Since it can be punched by, the dimensional accuracy is good, and the (G) metal plate is the main product, so workability is good and it is easy to incorporate it in the seal part of various machines. (H) The metal plate is the main product Has excellent aging resistance to heat,
(I) Asbestos joint sheet does not cause inconvenience due to fluffing of asbestos fibers, however, since this rubber coating gasket material is coated with a layer of synthetic rubber alone, it has the following drawbacks. Had.

(A) The heat resistance temperature is usually as low as about 150 ° C.

(B) When the tightening load is excessive, the surface rubber layer laterally flows and the rubber layer is easily peeled off. In particular, if there is a portion that receives excessive stress during embossing, the rubber layer laterally flows at that portion and is easily peeled off. If such peeling of the rubber layer occurs, naturally the gasket often leaks.

(C) When an excessive stress is applied, the torque of the bolt is likely to be reduced due to the lateral flow of the rubber.

(D) As the synthetic rubber layer becomes thicker, the lateral flow increases more and more, and due to the elasticity of the rubber,
Embossing becomes impossible (that is, even if the convex part of the mold presses the gasket material, it is absorbed by the deformation of the rubber and the metal plate part cannot be sufficiently deformed).
The thickness of the rubber layer is limited to about 100 μ on one side, and it is impossible to make it thicker than that.

Next, in order to solve the above-mentioned drawbacks of the rubber-coated gasket material, the rubber-asbestos-compound-coated gasket material is not a synthetic rubber alone but a rubber-asbestos compound containing asbestos. Is coated on the surface of a metal plate. However, in recent years, the adverse effects of asbestos on the human body have been pointed out, and the ban on the use of asbestos has become an imminent problem. For this reason, it has become necessary to construct the compound by using base fibers instead of asbestos. However, if the asbestos is simply replaced with a substitute fiber, it is not possible to create a compound because the substitute fiber is not uniformly dispersed in the rubber material, it is not possible to coat the metal plate, or the heat resistance is high. Satisfactory results could not be obtained due to problems such as inadequate properties and deterioration of sealing characteristics.

[0015] However, the applicant of the present invention has disclosed the Japanese Patent Publication No. 6-84.
According to the gasket material proposed in No. 785, the conventional rubber coating
Not only can the drawbacks of the gasket material be eliminated, but even when compared with the rubber asbestos compound coating gasket material, it is possible to obtain the same or even better performance in various physical characteristics and sealing characteristics.

The present invention has been made in view of the above circumstances, and one of the objects of the present invention is to further improve the gasket material proposed by the present applicant in Japanese Patent Publication No. 6-84785, and It is an object of the present invention to provide a gasket material which, when used for sealing, has good conformability to the flange surface and can obtain excellent water sealing property even at low surface pressure.

[0017]

A gasket material according to the present invention is a compound containing a base fiber composed of both compressive inorganic fibers other than asbestos and a compressible organic fiber, a rubber material, and an inorganic filler. In the gasket material obtained by coating the surface of a metal plate with the above layer, the compound further contains a water swelling agent.

The water swelling agent is, for example, a super absorbent resin (a resin having a structure in which the chains of an ionic, originally water-soluble electrolyte polymer are loosely cross-linked, and is several tens to several thousand times its own weight. The above water can be absorbed, the water does not separate even when pressure is applied, and the water is gradually released only after drying to return to the original size). As such a super absorbent polymer, for example, a vinyl alcohol acrylate copolymer can be used.

The amount of the compressive fiber and the filler in the compound is preferably 50% or more (by weight). The amount of the water swelling agent in the compound is preferably about 10%. The thickness of the compound layer is 50 to 6 on both sides.
About 00μ is preferable.

[0020]

In the gasket material of the present invention, since the metal plate is used as the core material, the tensile strength can be increased and the mechanical strength of the gasket as a whole is large as compared with the conventional non-metal gasket. At the same time, sufficient pressure resistance can be obtained even when the gasket seal width is narrow (for example, about 2 mm). Also, this reduces torque reduction.

Further, not the rubber alone, but the compound of the base material fiber made of both the compressible inorganic fiber other than asbestos and the compressible organic fiber and the rubber material is coated on the metal plate. Heat resistant temperature is improved compared to coating gasket material.

Further, since the compound of the base material fiber made of both the compressible inorganic fiber other than asbestos and the compressible organic fiber and the rubber material is coated on the metal plate instead of the rubber alone, the lateral flow of the coating layer is caused. Further, peeling is less likely to occur, and torque retention characteristics are also improved. Further, the thickness of the coating layer can be increased to 500 μ or more on one side, and embossing can be performed.

Since the surface layer (compound layer) is highly compressible and contains a water swelling agent, it swells when it comes into contact with water, so it has good conformability to the flange surface and is excellent even at low surface pressure portions. Excellent water sealing property can be obtained. Therefore, for example, sufficient water sealability can be maintained even in a low surface pressure portion such as when the gasket is flat or when the bolt span is wide and the flange is largely distorted.

Since compressible inorganic fibers other than asbestos are poor in flexibility, if only inorganic fibers other than asbestos are used as the base fibers, the sealing performance of the gasket material is lowered, while the organic fibers are heat resistant. Therefore, if only organic fibers are used as the base fibers, the heat resistance of the gasket material will deteriorate. In addition, the heat resistance of the filler is also reduced when an organic filler is used. However, by using the base fiber composed of both the compressible inorganic fiber and the compressible organic fiber and the inorganic filler as in the present invention, a gasket material satisfying both sealing performance and heat resistance can be obtained.

If the compound contains an oil swelling agent such as SBR (styrene-butadiene rubber), the oil swelling agent and thus the compound layer swells with the oil, so that the oil sealability at low surface pressure can be improved. .

When SBR is used as the oil swelling agent, it is preferable that the compound contains a non-oil swelling nitrile rubber (NBR) together with the SBR. This is because when SBR alone is used, the oil swelling property increases, but the pressure resistance deteriorates, but when NBR is also used, the pressure resistance can be increased and sufficient oil swelling property can be obtained. is there. Thus, when SBR and NBR are used together, the compounding ratio of both is SBR 70-5.
It is preferable to use 30 to 50 parts by weight of NBR with respect to 0 parts by weight.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the embodiments shown in the drawings.

A compound having the following composition was prepared.

(A) Glass fiber ... 50% by weight (b) Fibrillated aromatic polyamide fiber (trade name: Kepler pulp, manufactured by DuPont) ... 5% by weight (c) NBR ... 8% by weight (d) SBR. 8% by weight (e) Vinyl acrylate alcohol copolymer (trade name: Sumikagel SP-510 or SP-520, manufactured by Sumitomo Chemical Co., Ltd.) ... 10% by weight (f) Rubber chemicals ... 4% by weight (g) Inorganic Filler: 15% by weight In the above composition, the glass fiber is a kind of compressible inorganic fiber, and the fibrillated aromatic polyamide fiber is a kind of compressible organic fiber. Further, the vinyl acrylate alcohol copolymer is a kind of water swelling agent, especially a highly water-absorbent resin, as already described.

As the rubber chemicals, vulcanizing agents such as sulfur, zinc oxide, magnesium oxide, peroxides, dinitrorebenzene, and thiazole compounds, polyamine compounds, sulfenamide compounds, dithiocarbamate compounds. Vulcanization accelerators such as compounds, aldehyde amine compounds, guanidine compounds, thiourea compounds and xanthate compounds can be used.

As the inorganic filler, clay,
Talc, barium sulfate, sodium bicarbonate, graphite, lead sulfate, tripolylith, wollastonite, etc. can be used.

As shown in FIG. 1, by coating the layer 1 of the compound having the above-mentioned composition on both sides of the SPCC steel plate 3 previously coated with the heat resistant adhesive 2,
A gasket material was formed. In this embodiment, the steel plate 3
Has a thickness t ₁ of 0.2 mm, and the compound layer 1 has a thickness t ₂
Is 0.2 mm or 0.3 mm for each side of the steel plate 3.

In this gasket, since the metal plate is used as the core material, the tensile strength can be increased as compared with the conventional non-metal gasket, the mechanical strength of the gasket as a whole is large, and the gasket is Even if the seal width is narrow (for example, about 2 mm), sufficient pressure resistance can be obtained. Further, since the mechanical strength is high and the pressure resistance is excellent, the torque reduction is small.

Further, not the rubber alone, but the compound of the base material fiber made of both the compressible inorganic fiber other than asbestos and the compressible organic fiber and the rubber material is coated on the metal plate. Heat resistant temperature is improved compared to coating gasket material.

Further, since not the rubber alone but the compound of the base material fiber composed of both the compressible inorganic fiber other than asbestos and the compressible organic fiber and the rubber material is coated on the metal plate, the lateral flow of the coating layer is caused. Further, peeling is less likely to occur, and torque retention characteristics are also improved. In addition, the thickness of the coating layer can be increased and embossing can be performed.

In the present invention, the surface layer (compound layer 1) has a high compressibility, and since it contains a water swelling agent, it swells when it comes into contact with water, so that it has good conformability to the flange surface, Excellent water sealability can be obtained even in a low surface pressure area. Therefore, for example, sufficient water sealability can be maintained even in a low surface pressure portion such as when the gasket is flat or when the bolt span is wide and the flange is largely distorted.

Further, in this embodiment, since the compound layer 1 contains SBR having an oil swelling property, the compound layer 1 is swollen by the oil, so that the oil sealability at a low surface pressure can be improved. .

Table 1 shows ASTM. F-104 and F-
38 shows the result of having tested the general physical property of the gasket of the said Example based on 38. In addition, in the column of "measured value" in Table 1, (A) is when the compound layer 1 is 0.2 mm,
(B) shows the case where the compound layer 1 is 0.3 mm.

[0039]

[Table 1] Although a steel plate is used as the metal plate in the above-mentioned embodiments, other metal plates such as an aluminum plate and a stainless steel plate may be used in the present invention.

As the water swelling agent, a super absorbent polymer other than the vinyl acrylate copolymer or a water swelling agent other than the super absorbent resin can be used.

Although glass fibers are used as the inorganic fibers other than asbestos in the above-mentioned embodiments, other inorganic fibers such as ceramic fibers, rock wool, mineral wool, fused silica fibers, chemically treated fibers are used in the present invention. It is also possible to use silica fibers, fused silicate alumina fibers, continuous alumina fibers, stabilized zirconia fibers, boron nitride fibers, alkali titanate fibers, whiskers, boron fibers, carbon fibers, metal fibers and the like.

Although aromatic polyamide fibers are used as the organic fibers in the above embodiments, other organic fibers such as polyamide fibers, polyolefin fibers, polyester fibers, polyacrylonitrile fibers are used in the present invention. It is also possible to use polyvinyl alcohol fibers, polyvinyl chloride fibers, polyurea fibers, polyurethane fibers, polyfluorocarbon fibers, phenol fibers, cellulose fibers and the like.

In the above embodiment, SB is used as the rubber material.
Although R and NBR are used, other rubber materials such as isoprene rubber (IR), chloroprene rubber (CR), butadiene rubber (BR), butyl rubber (IIR), ethylene-propylene rubber (EP) are used in the present invention.
M), fluororubber (FPM), silicone rubber (S
i), chlorosulphonated polyethylene (CSM), ethylene vinyl acetate rubber (EVA), chlorinated polyethylene (CP)
E), butyl chloride rubber (CIR), shrimp chlorohydrin rubber (ECO), nitrile isoprene rubber (NIR),
Natural rubber (NR) or the like can also be used. Further, these rubber materials, for example, an oil-extended rubber obtained by adding a naphthene-based process oil to SBR can also be used as the rubber material.

However, as described above, when the compound layer 1 contains a rubber material having an oil swelling property such as SBR as in the above embodiment, the oil sealability at a low surface pressure can be improved. Further, even if an oil swelling agent other than the rubber material is contained in the compound layer 1, the oil sealability at a low surface pressure can be similarly improved.

[0045]

As described above, according to the gasket material of the present invention, not only the drawbacks of the conventional rubber coating gasket material can be solved without using asbestos, but also the rubber asbestos compound coating Compared with gasket materials, it can obtain the same or even better performance in various physical and sealing characteristics, and when used for water seals, it has very good conformability to the flange surface and low Excellent sealability can be obtained even with surface pressure. Further, if the compound layer also contains an oil swelling agent, the oil sealability at low surface pressure can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a gasket material according to the present invention.

[Explanation of symbols]

 1 compound layer 3 SPCC steel plate

Claims (7)

[Claims] 1. A surface of a metal plate is coated with a compound layer containing a base fiber composed of both a compressible inorganic fiber other than asbestos and a compressible organic fiber, a rubber material, and an inorganic filler. The gasket material according to claim 1, wherein the compound further contains a water swelling agent. 2. The gasket material according to claim 1, wherein the water swelling agent is made of a highly water-absorbent resin. 3. The gasket material according to claim 2, wherein the water swelling agent comprises a vinyl acrylate alcohol copolymer. 4. The gasket material according to claim 1, wherein the compound contains a rubber material having oil swelling property. 5. The gasket material according to claim 4, wherein the rubber material having oil swelling property is styrene-butadiene rubber (SBR). 6. The gasket material according to claim 5, wherein the compound contains nitrile rubber (NBR) together with SBR. 7. The gasket material according to claim 1, wherein the compound contains an oil swelling agent other than a rubber material.