JPH11181401A - Gasket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a gasket manifesting excellent high strength sealing properties and high strength heat resistance, useful for a gasket of an internal combustion engine and the like by including a steel reinforcing core plate layer which has an extension rate of a prescribed value or less and sealing layers laminated on the both sides of the core plate layer and allowing beads to be formed. SOLUTION: This gasket is constituted from a steel reinforcing core plate layer 1 having less than 15% of the extension rate, 500 N/mm<2> >= tensile strength and 0.1-0.3 mm of thickness and the sealing layer 2 including an expanded graphite laminated on the both sides of the steel plate and formed beads 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a gasket having excellent sealing properties. More specifically, the present invention relates to a gasket material for a cylinder head of an internal combustion engine, a gasket used to seal various joints of an internal combustion engine around oil, water, an intake system, an exhaust system, and the like.

[0002]

2. Description of the Related Art Conventional gasket materials include JIS-R
As shown in JP-3453, JIS-7S-40, etc., an asbestos joint sheet mainly using asbestos, a material in which asbestos and a reinforcing core plate are combined, and the like have been used. However, asbestos is harmed to the human body and its use is problematic. Therefore, as a gasket material not using asbestos, an organic and inorganic filler is kneaded with an organic binder such as rubber, for example, as shown in Nichias Technical Report, No. 241, published in March 1986. And Japanese Patent Application Laid-Open Nos. Hei 2-38760 and Hei 3-2290.
As shown in JP-A-69-69, for example, a so-called metal gasket material in which a rubber layer is coated on a surface of a metal plate such as a stainless steel plate or a normal steel plate is used.

However, a joint sheet formed by kneading an organic or inorganic filler with an organic binder such as rubber has a low heat-resistant temperature and a tensile strength of about 14.7 MPa (150 kgf / cm ² ). And it is difficult to use it at high temperature and high load application sites. In addition, a metal gasket material in which a rubber layer is coated on the surface of a steel plate is generally used by performing a bead (irregularity) process along a sealing portion and securing the sealing property by the compression restoring force of the bead. A metal gasket material using a normal steel plate as a steel plate has not only poor sealing properties due to a weak compression restoring force of a bead of the normal steel plate, but also a continuous use for a long time. Further, a metal gasket material using a stainless steel plate is very expensive.

[0004]

SUMMARY OF THE INVENTION The first aspect of the present invention is to provide a gasket having remarkably excellent sealing performance. The inventions according to claims 2 and 3 provide a gasket that is further excellent in sealing performance and has high strength, in addition to the object of the invention described in claim 1. The invention described in claim 4 provides a gasket that is particularly excellent in heat resistance and sealability, in addition to the objects of the inventions described in claims 1, 2, and 3.

[0005]

According to the present invention, an elongation percentage is 15%.
% Or less, and a gasket having a layer of a sealing material laminated on both sides of an iron reinforcing core plate and a bead formed on both sides thereof. The present invention also relates to a gasket in which the reinforcing core plate has a tensile strength of 500 N / mm ² or more. In the present invention, the reinforcing core plate may have a thickness of 0.1 to 0.1.
For a gasket that is 3 mm. The present invention also relates to a gasket in which the layer of the sealing material contains expanded graphite.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The gasket of the present invention has a reinforcing core plate layer and a sealing material layer laminated on both sides thereof.
The reinforcing core plate used in the present invention is required to have an elongation of 15% or less from the viewpoint of sealing properties and the like, preferably 10% or less, more preferably 5% or less. If the elongation exceeds 15%, there is a disadvantage that the bead strength of the gasket to be produced is reduced and the sealing property is reduced. The elongation percentage can be obtained as (elongation after test / length of test specimen before test) × 100 (%) by pulling a JIS Z 22015 test specimen until it is broken by a tensile tester.

The reinforcing core plate used in the present invention preferably has a tensile strength of not less than 500 N / mm ^2.
More preferably if 0N / mm ² or more, more preferably equal to 700 N / mm ² or more. If the tensile strength is less than 500 N / mm ² , the bead strength of the gasket to be produced is weak, and the sealing property after long-term use tends to decrease. Further, the tensile strength is preferably 2000 N / mm ² or less from the viewpoint of workability. The tensile strength was measured in accordance with JIS Z 22015.
It can be measured by pulling the test piece with a tensile tester and measuring the breaking strength.

Further, it is necessary that the material of the reinforcing core plate to be used is an iron plate in terms of good tensile strength, elongation and sealing properties. The thickness of the reinforcing core plate in the gasket of the present invention is preferably in the range of 0.1 to 0.3 mm. When the thickness of the reinforcing core plate used is less than 0.1 mm, the strength tends to decrease when a bead is formed as a gasket, and when it exceeds 0.3 mm, the workability tends to decrease.

A reinforcing core plate having such characteristics can be produced by rolling a normal steel plate. Further, if necessary, further annealing can be performed. Generally, by annealing an ordinary steel sheet, the crystal of the steel sheet is recrystallized, the tensile strength is reduced, and the elongation is increased. Therefore, the tensile strength and the elongation can be adjusted according to the annealing conditions.

[0010] The reinforcing core plate used in the present invention is preferably subjected to plating to prevent corrosion. The type of plating is not particularly limited, and examples thereof include hot-dip plating of zinc, nickel or the like, and electroplating. The gasket base material of the present invention can be manufactured by laminating a sealing material layer on both sides of the reinforcing core plate. The sealing material used in the present invention is not particularly limited as long as it is a material having a sealing property. For example, a rubber material including fluorine rubber, nitrile rubber, silicon rubber, a filler such as granular or fibrous, and an organic binder Sheets, inorganic sheets, expanded graphite sheets, etc. can be used, but a sealing material containing expanded graphite in terms of heat resistance and sealing properties when forming a gasket, specifically, an expanded graphite sheet should be used. Is preferred.

As the expanded graphite sheet, a sheet produced by a known production method can be used. For example, highly crystallized graphite such as natural graphite, quiche graphite, and pyrolytic graphite is immersed in a strongly oxidizing solution such as a mixture of concentrated sulfuric acid and nitric acid, or a mixture of concentrated sulfuric acid and hydrogen peroxide. To form a graphite intercalation compound, rinse with water, and then rapidly heat to obtain graphite crystal c.
A sheet obtained by cold-working graphite having compressive properties in an insect shape in which the axial direction is expanded is used.

The lamination of the sealing material on the reinforcing core plate is not particularly limited, but can be performed by, for example, a roll or a press via an adhesive. The adhesive to be used is not particularly limited, and for example, an adhesive containing a thermosetting resin such as a phenol resin and an epoxy resin as a main component is preferable in terms of heat resistance.

[0013] The thickness of the gasket sealing material layer is not particularly limited, but is preferably 0.03 in terms of sealing properties and bead workability.
It is preferably from 3 to 0.3 mm. Further, the thickness of the gasket including the reinforcing core plate and the sealing material is not particularly limited, but from the viewpoint of sealing properties and workability, is 0.16 to 0.9 mm.
It is preferred that The gasket of the present invention needs to be further formed with a bead in terms of sealing properties.

As the beads to be formed, full beads (convex beads) and half beads are preferable from the viewpoint of sealing properties. The height of the formed bead is preferably 0.1 to 0.9 mm from the viewpoint of sealing properties and the like. As a method of forming a bead, for example, a bead can be formed by pressing using a mold prepared to have a predetermined bead shape.

[0015]

Next, embodiments of the present invention will be described. Example 1 A hot-dip galvanized steel sheet having a tensile strength of 750 N / mm ² , an elongation of 2%, and a thickness of 0.23 mm (Steel Co., Ltd., S
GCH) on both surfaces of a phenolic resin adhesive dissolved in methyl ethyl ketone (Cemedine # 11, manufactured by Cemedine Co., Ltd.)
0) was applied, and the mixture was allowed to stand in a dryer at 80 ° C. for 1 minute to dry and remove methyl methyl ketone. Next, on both sides of this steel sheet, an expanded graphite sheet having a thickness of 0.3 mm (manufactured by Hitachi Chemical Co., Ltd.)
(Registered trademark Carbofit) was laminated, and the steel sheet and the expanded graphite sheet were bonded together using a hot press under the conditions of a temperature of 180 ° C. and a pressure of 30 kgf / cm ² . Further pass through the roll, the total sheet thickness after bonding 0.5mm, density of expanded graphite sheet layer 1.0g /
A sheet-shaped composite material of cm ³ was produced. FIG. 1 is a cross-sectional view of the obtained sheet-like composite material, where 1 is a galvanized steel sheet,
2 is an expanded graphite sheet layer. After punching this sheet-shaped composite material into a ring shape having an outer diameter of 50 mm and an inner diameter of 35 mm, as shown in FIG. 2, a full bead 3 having a height of 0.6 mm is formed into a circular shape having a diameter of 42 mm to obtain a gasket. Was.

Example 2 A hot-dip galvanized steel sheet having a tensile strength of 550 N / mm ² , an elongation percentage of 12% and a thickness of 0.23 mm (SG manufactured by Kawa Iron Steel Co., Ltd.)
CH), a phenolic resin adhesive (Cemedine # 110) dissolved in methyl ethyl ketone was applied to both sides, and 80 ° C.
Was left in a dryer for 1 minute to dry off methyl methyl ketone. Next, an expanded graphite sheet (Hitachi Kasei Kogyo Co., Ltd., trade name: Carbofit) having a thickness of 0.3 mm was laminated on both sides of the steel sheet, and was heated at 180 ° C. using a hot press.
The steel sheet and the expanded graphite sheet were bonded under a pressure of 30 kgf / cm ² . Further pass through the roll, the total thickness 0.5mm after bonding,
A sheet-like composite material having an expanded graphite sheet layer density of 1.0 g / cm ³ was produced. This sheet-shaped composite material has an outer diameter of 50 mm
And after punching into a ring shape with an inner diameter of 35 mm, a height of 0.3 mm.
A gasket was obtained by forming a full bead of 6 mm into a circle having a diameter of 42 mm.

Example 3 A hot-dip galvanized steel sheet having a tensile strength of 750 N / mm ² , an elongation of 2% and a thickness of 0.23 mm (SG manufactured by Kawa Iron Steel Co., Ltd.)
CH), a phenolic resin adhesive (Cemedine # 110) dissolved in methyl ethyl ketone was applied to both sides, and 80 ° C.
Was left in a dryer for 1 minute to dry off methyl methyl ketone. Then, on both sides, a fluoro rubber (Nippon Zeon)
Co., Ltd., trade name Nippol CMF700): Sulfur powder (manufactured by Hosoi Chemical Co., Ltd., colloidal sulfur): coated with a solution in which methyl ethyl ketone was mixed at a weight ratio of 10: 2: 20, and heat-treated at 60 ° C. for 10 minutes. 20 at 160 ° C
Heat-treated, vulcanized and cured rubber, 0.3mm thick
Was obtained. After punching this sheet-shaped composite material into a ring shape having an outer diameter of 50 mm and an inner diameter of 35 mm, a full bead having a height of 0.6 mm was formed into a circular shape having a diameter of 42 mm to obtain a gasket.

Comparative Example 1 A hot-dip galvanized steel sheet having a tensile strength of 360 N / mm ² , an elongation of 25%, and a thickness of 0.23 mm (SG manufactured by Kawa Iron Steel Co., Ltd.)
CC), apply a phenol resin adhesive (Cemedine # 110) dissolved in methyl ethyl ketone to both sides,
Was left in a dryer for 1 minute to dry off methyl methyl ketone. Then, on both sides of the steel sheet, an expanded graphite sheet having a thickness of 0.3 mm (trade name: Carbofit, manufactured by Hitachi Chemical Co., Ltd.) was laminated, and the temperature was set to 180 ° C. and the pressure was set to 30 kgf / cm ² using a hot press. Under the conditions, the steel sheet and the expanded graphite sheet were bonded. The sheet was further passed through a roll to prepare a sheet-like composite material having a total thickness of 0.5 mm after bonding and an expanded graphite sheet layer density of 1.0 g / cm ³ . FIG. 1 is a cross-sectional view of the obtained sheet-like composite material, wherein 1 is a galvanized steel sheet, 2 is an expanded graphite sheet layer, and 3 is an adhesive. After punching this sheet-like composite material into a ring shape having an outer diameter of 50 mm and an inner diameter of 35 mm, as shown in FIG.
A gasket was obtained by forming a circular shape of 2 mm.

Comparative Example 2 A hot-dip galvanized steel sheet having a tensile strength of 360 N / mm ² , an elongation of 25%, and a thickness of 0.23 mm (SG manufactured by Kawa Iron Steel Co., Ltd.)
CC), apply a phenol resin adhesive (Cemedine # 110) dissolved in methyl ethyl ketone to both sides,
Was left in a dryer for 1 minute to dry off methyl methyl ketone. Then, on both sides, a fluoro rubber (Nippon Zeon)
Co., Ltd., trade name Nippol CMF700): Sulfur powder (manufactured by Hosoi Chemical Co., Ltd., colloidal sulfur): coated with a mixed solution of methyl ethyl ketone at a weight ratio of 10: 2: 20, and heat-treated at 60 ° C. for 10 minutes. 20 at 160 ° C
Heat-treated, vulcanized and cured rubber, 0.3mm thick
Was obtained. After punching this sheet-shaped composite material into a ring shape having an outer diameter of 50 mm and an inner diameter of 35 mm, a full bead 3 having a height of 0.6 mm was formed into a circular shape having a diameter of 42 mm to obtain a gasket.

Next, the gaskets obtained in the above Examples and Comparative Examples were evaluated for gas sealing properties. For gas sealing, the gasket is sandwiched between aluminum flanges with a surface roughness of 10S and a thickness of 25mm, and tightened with a surface pressure of 10MPa. The flange is subjected to a heat cycle of 150 ° C / 1 hour and -30 ° C / 1 hour. Was measured. The resulting graph is shown in FIG.

As apparent from FIG. 3, the gaskets of Comparative Examples 1 and 2 are inferior in sealing performance. On the other hand, it was confirmed that the gaskets of Examples 1, 2, and 3 had excellent sealing properties.

[0022]

The gasket according to claim 1 has excellent sealing properties, and is a gasket material for a cylinder head of an internal combustion engine.
It is useful as a gasket used to seal various joints such as around oil, around water, an intake system, and an exhaust system of an internal combustion engine. Further, the gaskets according to claims 2 and 3 have remarkably excellent sealing properties and high strength in addition to the effects of the gasket according to claim 1. The gasket according to the fourth aspect is particularly excellent in heat resistance and sealing properties in addition to the effects of the gasket according to the first, second and third aspects.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a sheet-like composite material used in an example of the present invention.

FIG. 2 is a sectional view of a gasket according to the embodiment of the present invention.

FIG. 3 is a graph showing the sealing characteristics of gaskets in Examples and Comparative Examples of the present invention.

[Explanation of symbols]

 1 Galvanized steel sheet 2 Expanded graphite sheet layer 3 Full bead

Continued on the front page (72) Inventor Jun Fujita 3-3-1 Ayukawacho, Hitachi City, Ibaraki Prefecture Inside the Yamazaki Plant of Hitachi Chemical Co., Ltd. Sanwa Packing Industry Co., Ltd.

Claims (4)

[Claims] 1. A gasket comprising a layer of an iron reinforcing core plate having an elongation of 15% or less and a sealing material layer laminated on both sides thereof, and a bead formed. 2. The reinforcing core plate has a tensile strength of 500 N / mm ^2.
The gasket according to claim 1, which is as described above. 3. The gasket according to claim 1, wherein the reinforcing core plate has a thickness of 0.1 to 0.3 mm. 4. The gasket according to claim 1, wherein the sealing material layer contains expanded graphite.