JP2003185020A - Connection type gasket - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connection type gasket capable of being sufficiently connected at connected portions and capable of maintaining sealability even in large-sized frame plate-like and circular gaskets. <P>SOLUTION: This connection gasket is formed by connecting gaskets including expanded graphite sheets divided into multiple parts and core materials. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection type gasket used in automobiles, general industries and the like.

[0002]

2. Description of the Related Art Gaskets include a gasket having a complicated shape and having many sealing portions, and a gasket having a simple sealing portion and having a frame plate shape or a circular shape. In particular, when a large-sized frame plate-shaped or circular gasket is punched from an original material of the gasket, a large amount of unpunched material is generated, resulting in a high material cost per gasket.

Conventionally, in the case of the above-mentioned gasket, the gasket is divided into a plurality of pieces, punched out, combined, and then joined by resin. As the binder used for joining, epoxy resin, nitrile butadiene rubber, chloroprene rubber, etc. are generally used, although they differ depending on the gasket material. However, in the case of a gasket material using expanded graphite, there is a problem in that it cannot be sufficiently bonded by the conventional bonding method because it is soft and the interparticle strength of the cut surface is weak.

Further, when the connecting portion is a bolt hole portion to which a sufficient tightening surface pressure is applied, it is possible to use a piece of nitrile butadiene rubber or the like to connect the inner peripheral portion of the bolt hole portion depending on the gasket material. is there. However, since the gasket material and the material of the piece are different from each other, sufficient coupling cannot be expected due to the difference in thermal expansion difference, and also the difference in compressibility and the sealability of both end surfaces of the piece are not sufficient, resulting in poor practicality.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a connection type gasket which is capable of maintaining a sufficient sealing property and sufficient sealing even at a large frame plate-shaped or circular gasket. .

[0006]

DISCLOSURE OF THE INVENTION The present invention relates to a connection type gasket formed by connecting a plurality of expanded graphite sheets and a gasket containing a core material. The present invention also relates to a connection-type gasket whose core material is glass fiber, SUS steel plate, general engineering steel plate, or aluminum steel plate. Further, the present invention relates to a connection-type gasket in which a connection portion is a bolt hole portion and a ring-shaped molded body containing expanded graphite and resin is interposed in an inner peripheral portion of the bolt hole.

The present invention also relates to a connection type gasket in which resin-containing expanded graphite sheets are placed on both sides of the connection portion. The present invention also relates to a linked gasket in which the resin used for the ring-shaped molded body and the resin applied to the expanded graphite sheet are phenol resins containing a dihydrobenzoxazine ring and undergoing ring-opening polymerization. Furthermore, the present invention relates to a connection type gasket in which a ring-shaped molded body and an expanded graphite sheet with a resin are integrally molded by hot pressing.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The connected gasket according to the present invention is obtained by using an expanded graphite sheet as a covering material and combining it with a core material. As a preferred manufacturing method, the connecting points are joined by a molded body in which expanded graphite and a resin are mixed, the expanded graphite sheets with resin are pasted on both sides thereof, and further the joining of the joining points and the joining of the expansive graphite sheets on both sides of the joining points This is a method of simultaneously performing the hot pressing. In the present invention, the core material is not particularly limited, but it is preferable to use glass fiber, SUS steel plate, general engineering steel plate, aluminum steel plate and the like.

The expanded graphite used for the expanded graphite sheet is
It is obtained by immersing raw material graphite in a solution containing an acidic substance and an oxidizing agent to generate a graphite intercalation compound, and then rapidly heating it to expand the C axis direction of the graphite crystal. As a result, the expanded graphite becomes a worm-like shape and has a entangled complex shape with no directivity.

The raw material graphite is not particularly limited,
Preferable examples are highly crystallized graphites such as natural graphite, cache graphite and pyrolytic graphite. Natural graphite is preferable in consideration of the balance between the obtained properties and economy. The natural graphite used is not particularly limited, and F4
8C (Nippon Graphite Co., Ltd., trade name), H-50 (Chuetsu Graphite)
Commercially available products such as those manufactured by K.K. can be used. These are preferably used in the form of scale-like powder.

Further, as the acidic substance used for the treatment of expanded graphite, generally, an acidic substance such as sulfuric acid which can penetrate between the layers of graphite and generate acidic roots (anions) having sufficient expansion ability is used. . Further, as an oxidizing agent used together with an acidic substance, hydrogen peroxide, potassium perchlorate, potassium permanganate, peroxides such as potassium dichromate, or an acid having an oxidizing action such as nitric acid can be used, Hydrogen peroxide is particularly preferable from the viewpoint of easily obtaining good expanded graphite.

The acidic substance and the oxidizing agent are preferably used in the form of an aqueous solution. Sulfuric acid as an acidic substance is used at an appropriate concentration, but a concentration of 95% by weight or more is preferable, and concentrated sulfuric acid is preferably used.

The expanded graphite sheet used for the gasket material can be obtained by applying pressure to the expanded graphite obtained above with a press or a rolling roll. The plate thickness of the expanded graphite used as the covering material of the gasket depends on the tightening surface pressure of the gasket and the proper plate thickness at the time of tightening, but in practice, the plate thickness of the expanded graphite sheet is 0.1 mm to 2 mm per side. The range of 0.0 mm is preferable.
When the plate thickness is less than 0.1 mm, the moldability of the expanded graphite sheet tends to deteriorate, and when the plate thickness exceeds 2.0 mm, the shear strength of the gasket becomes weak and the sealing function cannot be ensured. Tend. The plate thickness is more preferably 0.4 mm to 0.8 mm in order to improve the balance of the tightening surface pressure of the connecting part and the part other than the connecting part.

[0014] The density of the expanded graphite sheet is practically range from 200kg ^{/ m 3} ~2000kg ^/ m 3 is preferred. If the density is less than 200 kg / m ³ , expandable graphite sheet moldability and sealability tend to deteriorate, and
If it exceeds 0 kg / m ³ , it is difficult to uniformly receive the surface pressure, and the sealing property tends to deteriorate. To improve the balance of the connecting portion and the fastening surface pressure of the non-connecting portion, and more preferably ranges density of ^{700kg / m 3 ~1200kg / m 3} .

In the present invention, it is preferable that the connecting portion is a bolt hole portion, and if a connecting molded body is interposed in the inner peripheral portion of the bolt hole portion, the sealing performance is excellent, and the shape is ring-like. It is preferable to use a molded body. The molded article for connection is, for example, expanded graphite or compression molded into a sheet by applying pressure to the expanded graphite, and then dry-mixed with a pulverized powder that has been pulverized to a predetermined particle size and the resin, It is obtained by temporarily forming into a sheet shape while applying heat and punching into a required shape. The expanded graphite described above, the generation of gas contained in the expanded graphite during temporary molding is small, when mixed with the resin, entanglement of the expanded graphite remains, it is easy to ensure the reinforcing effect of the resin, the strength of the molded body In order to secure the above, it is preferable to use crushed powder obtained by crushing the expanded graphite sheet.

The method of mixing the crushed powder of expanded graphite sheet and the resin is not particularly limited, and a shaker, a V blender or the like that does not apply a large shearing force to the expanded graphite at the time of mixing in order to prevent the crushed powder of the expanded graphite sheet from being pulverized. It is preferably according to the dry mixing method used. When the crushed powder of the expanded graphite sheet is pulverized at the time of mixing, the strength of the obtained molded body tends to be rapidly reduced.

The resin used in the molded article for connection and the resin used together with the crushed powder of the expanded graphite sheet are not particularly limited as long as they are thermosetting resins, but in consideration of cost and characteristics, powdery epoxy resin, phenol It is preferable to use a resin, a melamine resin, or the like. Further, these resins are used in combination with a curing agent, a curing accelerator, etc., if necessary. Among these resins, it is preferable to use a phenol resin in terms of heat resistance, economy and workability. As the phenolic resin, it is more preferable to use a ring-opening polymerization type powdery type phenolic resin containing a dihydrobenzoxazine ring in the molecular structure, which generates less gas during the curing reaction.

There is no limitation on the plate thickness and the specific gravity of the molded article for connection, but the plate thickness is appropriately set depending on the total plate thickness of the gaskets to be connected and the plate thickness when the gasket is properly tightened. This is because when the plate thickness of the molded body for connection is extremely thicker than the total thickness of the gasket, the surface pressure is concentrated on the molded body for connection, the surface pressure balance of the entire gasket is lost, and the sealing property tends to be significantly deteriorated. . On the contrary, if the plate thickness of the molded body for connection is extremely smaller than the total plate thickness of the gasket, a gap is formed on the upper and lower surfaces of the connection portion, and the sealing property tends to be deteriorated.

Further, it is preferable to mount an expanded graphite sheet with a resin on both sides of the connecting portion, that is, both ends of the connecting molded body, because the sealing property is excellent. The expanded graphite sheet used for this portion is a sheet having a resin coated on one side.
The resin used is not particularly limited, but a phenol resin is preferable from the viewpoint of heat resistance, heat resistance, economic efficiency, workability, etc., like the resin used for the molded article for connection.

The phenol resin is more preferably a powder-type phenol resin of a ring-opening polymerization type containing a dihydrobenzoxazine ring in the molecular structure because it generates less gas during the curing reaction. There is no particular restriction on the plate thickness and specific gravity of the expanded graphite sheet used on both sides of the connecting portion, and it is appropriately determined depending on the plate thickness and specific gravity of the expanded graphite used for the gasket clothing material.

As shown in FIG. 2, the connecting method is such that the divided gasket 1 and the divided gasket 2 are combined at the tightening bolt hole 3 portion as shown in FIG. 3, and the ring for connection is attached to the inner peripheral portion of the bolt hole 3. The expanded graphite sheet 5 with resin is placed on the upper and lower surfaces of the shaped body 4 and pressure is applied while applying heat. The temperature at this time is equal to or higher than the curing temperature of the resin to be used, and the pressure is applied to the expanded graphite sheet of the gasket covering portion other than the connecting portion so as not to apply a load, so that the connecting type gasket shown in FIG. 1 can be obtained. .

[0022]

EXAMPLES The present invention will be described below with reference to examples. Example 1 A gasket is made of SPC with a thickness of 0.2 mm as a core material.
A C steel sheet was used, and expanded graphite sheets with an adhesive were attached to both sides of this SPCC steel sheet to produce a gasket having a total thickness of 1.0 mm (manufactured by Hitachi Chemical Co., Ltd., trade name MR).
C-100). The expanded graphite density at this time is 900 kg /
It was m ³ . This gasket was punched into the shape shown in FIG. 2 and divided.

Next, the plate thickness is 1.0 mm and the density is 100.
Expanded graphite sheet with 0 kg / m ³ (Hitachi Chemical Co., Ltd.)
Product name: Carbofit HGP-5) manufactured by Co., Ltd. was crushed by a coarse crusher and a fine crusher to obtain an expanded graphite sheet crushed powder having an average particle size of 100 μm. Next, 0.3 kg of powdery phenolic resin having a dihydrobenzoxazine ring in the molecular structure (Hitachi Chemical Co., Ltd., trade name HR1060) was added and dry mixed with a small V blender to obtain 1.0 kg of mixed powder. It was

The mixed powder obtained above was compression molded with a simple sheet molding machine to obtain a sheet having a plate thickness of 1.2 mm. After this,
A ring-shaped molded body for connection was obtained by punching into a ring shape having an outer diameter of 14 mm and an inner diameter of 12 mm so as to be inserted into the inner peripheral portion of the divided bolt hole 3 shown in FIG.

On the other hand, the plate thickness is 0.5 mm and the density is 200.
A powdered phenolic resin (trade name: HR1060, manufactured by Hitachi Chemical Co., Ltd.) was added to an expanded graphite sheet of kg / m ^{3 in} an amount of 0.
It was applied at a rate of 006 kg / m ² , and this was punched out to a size larger than the outer diameter of the ring-shaped molded body to obtain an expanded graphite sheet with an adhesive.

Next, each of the materials obtained above was set as shown in FIG. 3, then compressed by a hot press preheated to 180 ° C., and held at a pressure of 2 MPa for 20 minutes, and then, as shown in FIG. The connected gasket shown in FIG.

Example 2 For a gasket, a glass cloth prepreg with an adhesive having a plate thickness of 0.2 mm was used as a core material, and expanded graphite sheets were attached to both surfaces of the glass cloth prepreg with an adhesive to give a total plate thickness. A 1.0 mm gasket was prepared.
(Manufactured by Hitachi Chemical Co., Ltd., trade name GRC-503). The expanded graphite density at this time was 900 kg / m ³ . This gasket was punched into the same shape as in Example 1 and divided. Thereafter, the same steps as in Example 1 were performed and compression was performed with a press to obtain a connected gasket.

Comparative Example 1 The gasket (trade name: MRC-100, manufactured by Hitachi Chemical Co., Ltd.) obtained in Example 1 was punched into a gasket shape having the dimensions after connection without division to obtain a continuous integral gasket. It was

Next, the seal test of each gasket obtained in the above-mentioned Examples 1, 2 and Comparative Example 1 was conducted. The results are shown in Table 1. In the seal test, as shown in FIG. 4, two flanges 7 each having a plate thickness of 20 mm were used, a gasket 8 was interposed between the flanges 7, and a bolt 9 was used to apply a tightening surface pressure to 0. 1 MPa unit and 10
Air injection port 10 at intervals of 0.1 MPa every 0.1 MPa
The inner pressure of the air is increased from 0.5 MPa, and the maximum inner pressure is 0.5 MPa.
When it became, it was judged by confirming the presence or absence of water bubbles generated in water.

[0030]

[Table 1]

As shown in Table 1, it was confirmed that the connecting type gaskets according to the examples of the present invention have the same sealing property as the continuous integral gasket of the comparative example 1.

[0032]

INDUSTRIAL APPLICABILITY The connection type gasket of the present invention is industrially extremely suitable, even in a large frame plate-shaped or circular gasket, because it sufficiently bonds the connection points and has excellent sealing characteristics.

[Brief description of drawings]

FIG. 1A is a plan view showing a connecting portion of a connection type gasket according to an embodiment of the present invention, and FIG. 1B is a sectional side view thereof.

FIG. 2 is a plan view of a split gasket.

FIG. 3 is a schematic cross-sectional view showing a setting state during thermocompression molding.

FIG. 4 is a side view showing a seal test method.

[Explanation of symbols]

1 split gasket 2 split gasket 3 bolt holes 4 Ring-shaped molded body 5 Expanded graphite sheet with resin 6 Indicator pin 7 flange 8 gasket 9 bolts 10 Air inlet

Claims (6)

[Claims] 1. A connection type gasket formed by connecting a plurality of expanded graphite sheets and a gasket containing a core material. 2. The connected gasket according to claim 1, wherein the core material is glass fiber, SUS steel plate, steel plate for general engineering materials, and aluminum steel plate. 3. The connection type gasket according to claim 1, wherein the connection portion is a bolt hole portion, and a ring-shaped molded body containing expanded graphite and resin is interposed in an inner peripheral portion of the bolt hole. 4. The connected gasket according to claim 1, wherein expanded graphite sheets with a resin are placed on both surfaces of the connected portion. 5. The linked gasket according to claim 3, wherein the resin used for the ring-shaped molded body and the resin applied to the expanded graphite sheet are phenol resins containing a dihydrobenzoxazine ring and undergoing ring-opening polymerization. 6. The linked gasket according to claim 3, 4 or 5, wherein the ring-shaped molded body and the expanded graphite sheet with resin are integrally molded by hot pressing.