JP2602086B2 - Heat resistant gasket - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant gasket suitable as a gasket for an exhaust system in an engine of an automobile, a truck, a ship, or other various transportation means.

2. Description of the Related Art Since the exhaust gas during operation of the engine is at a high temperature of 500 ° C. or more, it is used for a gasket used for an exhaust system of an engine, for example, for an exhaust manifold, a gasket used for a connection between an exhaust pipe and a turbocharger. For example, a heat-resistant material that can maintain required sealing properties even when exposed to such a high temperature for a long time is required.

To meet this demand, a so-called case type gasket in which both sides of a carbon base sheet formed into a predetermined gasket shape are covered with a heat-resistant thin metal plate has been conventionally known. This gasket was developed focusing on the fact that carbon exhibits extremely excellent heat resistance in a state where the carbon is shielded from the atmosphere, especially oxygen, and the entire heat-resistant metal sheet covers the carbon base sheet from oxygen. It is applied for the purpose of blocking protection. This case-type gasket exhibits an excellent sealing effect in the above-mentioned high temperature range due to the elasticity of the internal carbon base sheet and the protective action of the external heat-resistant metal envelope.

Problems to be solved By the way, in the case type gasket, it is necessary to apply a heat-resistant metal sheet on the carbon base sheet in order to completely shield the carbon base sheet from the outside air. It is difficult to perform the heat treatment, and in the actual product, a gap is formed at the joint of the heat-resistant metal sheet. In addition, the flange repeatedly undergoes thermal expansion and contraction due to large temperature changes that occur during operation and when the engine is stopped, and the seams of the heat-resistant metal sheet of the case-type gasket spread due to this are wider than at the time of initial installation. Specifically, oxygen infiltrates into the gasket, and as a result, the internal carbon base sheet is subjected to the high temperature and oxygen, and furthermore, strong vibrations from the engine acting in a direction to destroy the structure of the carbon base sheet itself. In addition, there is often a problem that disappears in an unexpectedly short time.

In view of the above-mentioned drawbacks of the carbon-based sheet, the present inventors have further attempted to develop a case-type gasket having a core material of an asbestos sheet conventionally known as a heat-resistant fiber. It was also found that a satisfactory product could not be obtained because of the defect.

Under the circumstances described above, it is necessary to develop a case gasket that maintains excellent heat resistance for a long time even when the heat-resistant metal sheet is applied relatively roughly.

Means for solving the problems The present invention, as means for solving the above problems,
At least both sides of the core sheet formed into a predetermined gasket shape and both sides of the gas passage opening are covered with a heat-resistant metal sheet, and the core sheet has a heating loss of 5% by weight at 700 ° C. for 1 hour. % Or less of inorganic components is contained by 74% by weight or more,
850 ° C in an atmosphere containing oxygen as its inorganic component, 3
It is an object of the present invention to provide a heat-resistant gasket comprising at least a sheet layer containing 15% by weight or more of high-heat-resistant fiber having a residual tensile strength of 80% or more after heating for 0 minutes. is there.

Effect of the Invention The core sheet used in the heat-resistant gasket of the present invention contains at least 74% by weight of an inorganic component having a heating loss of 5% by weight or less at 700 ° C. for 1 hour, and an oxygen-containing atmosphere as the inorganic component. It has at least a sheet layer containing 15% by weight or more of high heat resistant fibers (hereinafter referred to as component A) having a residual tensile strength of 80% or more after heating at 850 ° C. for 30 minutes below. Therefore, when the core material sheet is formed as a composite structure of a sheet layer and a metal plate or the like, the above-described configuration conditions are evaluated based only on the sheet layer portion that does not include the metal plate or the like. By forming a sheet layer that satisfies the above-mentioned constitutional conditions, the loss on heating at 700 ° C. for one hour is reduced by 30%.
% Or less (hereinafter, this may be referred to as a second condition). In the following,
The material for forming the sheet layer may be abbreviated as the composition of the present invention.

The composition of the present invention contains at least 10% by weight of the above-mentioned component A as a main component. The component may be used for a long time at a high temperature during operation of the engine as well as at a low temperature as long as the second condition is satisfied. Over time, it functions as a structural material that gives the composition of the present invention an appropriate elasticity. Moreover, this function at high temperatures does not matter with or without oxygen. Therefore, the gasket of the present invention has two points: the core material sheet itself is excellent in heat resistance, and at least both front and back surfaces and the gas passage opening side surface of the core material sheet are covered with a heat-resistant metal sheet. Has a synergistic effect, so that even if the covering with the heat-resistant metal sheet is somewhat incomplete, the gasket as a whole maintains excellent heat resistance in a real machine test for a long period of time, as shown in Examples described later.

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the present invention will be described in detail with reference to the drawings. 1 is a top view of one embodiment of the present invention, FIG. 2 is a sectional view taken along line XX of FIG. 1, and FIG. 3 is another embodiment taken along line XX of FIG. It is sectional drawing of an example.

In FIGS. 1 to 3, reference numeral 1 denotes a stamped and formed gasket having one gas passage port 4;
A core sheet 2 having two fastening bolt holes 5 and 2 are formed in substantially the same shape as the core sheet 1 and
The heat-resistant metal sheet 3 provided so as to cover the upper surface of the sheet 1 covers the lower surface of the core sheet 1 and simultaneously covers the entire outer peripheral side surface of the sheet 1 and the side surface of the gas passage port 4. This is a heat-resistant metal sheet that covers up to the upper surface. As the heat-resistant thin metal plates 2 and 3, for example, a stainless plate having a thickness of 0.1 to 0.3 mm, particularly a stainless plate such as SUS310S or SUS304 is preferable.

In the present invention, the overlapping portion of the heat-resistant metal sheets 2 and 3 may be welded, or may be simply mechanically pressed. In order to produce the gasket of the present invention at a low cost, it is more preferable to only mechanically press the gasket.

The side surfaces of the tightening bolt holes 5 may also be covered with the heat-resistant thin metal plate 3. However, if the bolt holes 5 are not exposed to high-temperature outside air when the gasket is tightened between the flanges with bolts, FIG. It is not necessary to cover with the heat-resistant metal sheet 3 as shown in FIG. The entire outer peripheral side surface of the core sheet 1 may not be required to be covered, but it is generally preferable to cover the core sheet 1 with the heat-resistant thin metal plate 3 as shown.

The core material sheet 1 may be composed only of the composition of the present invention as shown in the embodiment of FIG. 2, or may be made of a heat-resistant metal plate 11 such as a hook iron plate as shown in the embodiment of FIG. It may have a composite structure composed of the invention composition layer 12.

As the metal plate 11, a metal plate having hooks on both sides, which is conventionally known for a steel vest, can be used. The metal plate 11 may be provided inside or on the surface of the composition sheet of the present invention. Instead of the metal plate 11, a well-known plate having a hook on one side or a mere flat plate without a hook on both sides can be used for a power vest.

Examples of the component A as the main component of the composition of the present invention include silica-alumina-CaO-MgO fiber, silica fiber, alumina fiber, alumina-silica fiber, alumina-polyarsilica fiber, silica-alumina-MgO fiber, and potassium titanate fiber. Glass fibers such as zirconia fiber, silicon carbide fiber, silicon nitride fiber, etc., natural quartz glass fiber, synthetic pure quartz glass fiber, high softening point silicate glass fiber, etc., stainless steel fiber, tungsten fiber etc. Examples thereof include melting point metal fibers. A
The component preferably has a thickness of 0.1 to 50 μm, particularly about 1 to 30 μm, and a length of 1 to 150 mm, particularly about 5 to 100 mm.

The composition of the present invention may be composed of only one or more of the component A which does not show substantial weight loss when heated at 700 ° C. for 1 hour, or may satisfy the above first and second conditions. As long as it is possible, it may be a mixture with one or more of the other materials described below. However, when other kinds of materials are used in combination, if the content of the component A in the composition of the present invention is too small, the function as a structural material in the core sheet is insufficient, and the sealing function of the gasket tends to be deteriorated. Become. Therefore, the content of the component A in the composition of the present invention is at least 10
% By weight, preferably at least 15% by weight, in particular at least 20% by weight.

Examples of other materials other than the component A include a heat-resistant material having a heating loss at 700 ° C. × 1 hour of 5% by weight or less, preferably 2% by weight or less (excluding the component A; hereinafter, referred to as component B); Organic polymer fibers (referred to as component C), inorganic binders (referred to as component D), organic binders (referred to as component E), and the like. In the present invention, the weight loss on heating (the composition of the present invention and those of the component B) refers to an amount excluding water and volatile substances absorbed during storage in any case. Specifically, the material to be tested is heated at 105 ° C for 1-2
It means the amount detected by heating at 700 ° C. for 1 hour in the air after heating and drying for an hour.

As the B component, fibers such as rock wool, C glass, E glass, and metal fibers (hereinafter, referred to as B component fibers), powder of the same material as the B component fiber, powder of the same material as the A component, talc, clay , Mica powder, swollen vermiculite,
Examples thereof include dry sand of rivers and coasts, and powders of various other heat-resistant ores (hereinafter, referred to as B component powders). The B component fiber has a thickness of 0.1 to 50 μm, particularly 1 to 30 μm.
It is preferable that the length is about m and the length is about 1 to 150 mm, particularly about 5 to 100 mm. The B component powder has an average particle size of 1 to 700 μm, particularly 200 μm.
m or less is preferable.

As the component C, fibers such as aromatic polyamide, aromatic polyester, phenol resin, and carbon, and natural organic fibers such as kraft pulp can be used. Examples of commercially available products include Kevlar (trade name, manufactured by DuPont), Twaron (trade name, manufactured by Akzo), and Kyonol (trade name, manufactured by Kainol Japan). The thickness of the C component is 0.1-100μ
m, especially 1 to 50 μm, length is 1 to 300 μm, especially 2 to 50 m
m is preferred.

As the D component, not only those which are inorganic in an uncured state or a semi-cured state, but also those which are essentially inorganic in a state where they are substantially organic even if they are organic even in those states. Used. For example, various types of ceramic silicon (for example, CELA400 manufactured by Kansai Paint Co., Ltd. and AY49 manufactured by Toray Silicone Co., Ltd.)
-208), silica-based solution (for example, Sumiseram PN2010 manufactured by Asahi Chemical Industry Co., Ltd.) and the like. When the D component is contained in the composition of the present invention in an appropriate amount, the cohesion of the core sheet when heated to a high temperature is improved.

Examples of the E component include an NBR emulsion, an acrylic emulsion, and an aqueous polyvinyl alcohol solution. When an appropriate amount of the E component is used, production of a sheet of the composition of the present invention and handling of the obtained sheet in a normal state become easy.

Hereinafter, the amounts of the components B to E when they are used will be described.

Component B is preferably from 5 to 600 parts by weight, particularly preferably from 10 to 400 parts by weight, per 100 parts by weight of component A. It is particularly preferable to use at least one of the component B fibers in an amount of 10 to 200 parts by weight per 100 parts by weight of the component A.

The C component and the E component have a property of burning or decomposing at a high temperature, and thus their total use amount (the E component including the solvent and the dispersion medium is the solid content weight, and so on).
Is required to be a small amount of less than 30% by weight, and it is preferable that all components are small amounts of 10% by weight or less, preferably 5% by weight or less in the composition of the present invention. In the following, it is particularly preferable not to use.

The use amount of the D component (solid content weight for the D component including the solvent and the dispersion medium, the same applies hereinafter) is preferably 5 to 300 parts by weight, particularly preferably 30 to 200 parts by weight, per 100 parts by weight of the A component.

In general, the higher the density of the composition of the present invention in the state of the core sheet, the better the long-term sealing properties of the gasket. Therefore, the grammage (in the case of a composite structure as shown in FIG. 3, the total grammage of the layer composed of the composition of the present invention)
800 g / m ² or more, especially 1000 g / m ² or more, further 1200 g / m ²
It is preferable that it is above. A sheet having a high grammage may be obtained by stacking one of the raw material sheets or a plurality of sheets of the raw material sheet at room temperature to 20 ° C.
It can be obtained by pressing at a high temperature of about 0 ° C.

The thickness of the composition layer of the present invention in the core sheet (in the case of a composite structure as shown in FIG. 3, the total thickness of the layer composed of the composition of the present invention) is 0.5 to 2.5 mm, preferably 1.0 to 2.0 mm. mm.

 Hereinafter, preferred embodiments of the composition of the present invention will be described.

(1) A compressed sheet comprising only the component A, or a composition comprising the component A and a very small amount, particularly 5 parts by weight or less, preferably 2 parts by weight or less of the component D and / or E per 100 parts by weight of the component A Stuff.

(2) A composition comprising A component 100 parts by weight and B component fiber 5 to 250 parts by weight.

(3) A component 100 parts by weight, B component fiber 5 to 200 parts by weight,
A composition comprising 10 to 200 parts by weight of component B powder and 5 to 100 parts by weight of component D.

(4) A component 100 parts by weight, B component fiber 5 to 200 parts by weight,
A composition comprising 10 to 300 parts by weight of component B powder, 1 to 10 parts by weight of component C, and 1 to 100 parts by weight of component D.

(5) A component 100 parts by weight, B component fiber 5 to 200 parts by weight,
A composition comprising 10 to 300 parts by weight of component B powder, 1 to 10 parts by weight of component C, and 1 to 10 parts by weight of component E.

(6) A composition having a heating loss at 700 ° C. for 1 hour of 20% by weight or less, particularly 10% by weight or less.

Effect of the Invention The present invention relates to an improved case gasket, and as a core sheet material covered with a heat-resistant metal sheet, a high mechanical strength even when heated to a high temperature in a state of contact with the outside air containing oxygen. Since a composition containing a high heat-resistant fiber as a main component that can maintain the mechanical strength is used, sufficient high-temperature sealing property is exhibited even if the core material sheet is slightly incompletely covered with the heat-resistant metal sheet.
Therefore, the gasket of the present invention exhibits extremely high performance as an exhaust system gasket for various engines, because it is easy to manufacture and has a stable sealing property at a high temperature.

Examples Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

Example 1 Alumina-silica fiber as component A (average thickness 1.9 μm)
m, average length 70 mm) 80% by weight of alumina silica powder (shot) as a B component powder and 20% by weight of IBIDEN J (a shotless product) manufactured by IBIDEN Co., Ltd.
A sheet-like composition (solids content 102.8 parts by weight) consisting of 100 parts by weight, 2 parts by weight of the NBR emulsion as the E component in terms of its solid content, and 16 parts by weight of a 5% by weight alum aqueous solution was formed into a sheet. The sheet thus obtained was subjected to high-pressure pressing at room temperature to obtain a sheet having an average thickness of 1.0 mm and a basis weight of 750 g / m ² . Then, two sheets (total basis weight: 1500 g / m ² ) are applied to both sides of a hook iron plate (thickness: 0.2 mm) having hooks on both sides to obtain a steel vest type core material sheet (thickness: 1.6 mm). Was.

A core sheet having the structure shown in FIG. 1 was punched out of the core sheet material thus obtained, and a wrapped gasket having the structure shown in FIG. 3 was obtained using a SUS310S stainless steel plate having a thickness of 0.25 mm.

Example 2 Alumina-silica fiber as component A (average thickness 1.9 μm)
m, average length: 70 mm) 50 parts by weight of alumina silica powder (shot) as a B component powder and 50 parts by weight of IBIWOOL J (shot product) 63 parts by weight, manufactured by IBIDEN Co., Ltd., B component fiber Glass fiber (thickness 11μm, average length 13mm, trade name of Fuji Fiberglass Co., Ltd.)
FES-13) 27 parts by weight, 7 parts by weight of kraft pulp (approximately 50 μm in thickness, average length 2.0 mm) as the C component, and expanded vermiculite (average particle size of approximately 0.5 mm, Hirishi Chemical) as the B component powder 40 parts by weight of Hilcon S # 80 manufactured by Kogyo Co., Ltd.
A porridge composition (solids content of 144 parts by weight) consisting of 5 parts by weight of the NBR emulsion as the E component and 40 parts by weight of a 5% by weight alum aqueous solution was formed into a sheet to obtain a sheet. The obtained sheet was pressed at 120 ° C. to obtain a sheet having an average thickness of 1.0 mm and a basis weight of 930 g / m ² . Then, the two sheets were respectively applied to both sides of a hook iron plate (thickness: 0.2 mm) having hooks on both sides to obtain a steel vest type core material sheet (1.6 mm in thickness).

A core sheet having the structure shown in FIG. 1 was punched out of the core sheet material thus obtained, and a wrapped gasket having the structure shown in FIG. 3 was obtained using a SUS310S stainless steel plate having a thickness of 0.25 mm.

Example 3 Kraft pulp was used in an amount of 4 parts by weight, the NBR emulsion was used as a solid content in an amount of 4 parts by weight, and the average thickness was 1.0 m.
Example 2 except that a sheet having a basis weight of 950 g / m ² was obtained.
A core sheet material (thickness: 1.6 mm) of a steel vest type was obtained in the same manner as in Example 1, and a case type gasket having the same structure was obtained in the same manner as in Example 1.

Example 4 In the formulation of Example 2, no NBR emulsion was used, and the average thickness was 1.8 mm with the amount of kraft pulp used being 15 parts by weight.
A sheet having a basis weight of 1600 g / m ² was obtained. From the sheet thus obtained, a core sheet having the structure shown in FIG.
Using a 2 mm SUS304 stainless steel plate, a case type gasket having the structure shown in FIG. 2 was obtained.

Examples 5 to 9 Alumina silica fiber, glass fiber, kraft pulp,
In the same manner as in Example 2 except that the types and amounts (parts by weight) of kainol, expanded vermiculite, NBR emulsion, and inorganic binder were changed as shown in the table below, all had an average thickness of 1.0 mm and a basis weight of 930.
g / m ² sheet. The amount of all inorganic binders was unified to 20 parts by weight.
When used, a sheet obtained by forming a material other than the above is immersed in the inorganic binder and applied.
Was used, spraying was performed on the surface of the sheet obtained by papermaking.

Next, two sheets of each sheet were applied to both sides of a hook iron plate (thickness: 0.2 mm) having hooks on both sides to obtain a steel vest type core sheet material (thickness: 1.6 mm). Similarly, a case type gasket having the same structure was obtained.

Example 10 A case gasket different from that of Example 4 was obtained only in that the outer peripheral side face was not covered with a thin metal plate.

Comparative Example 1 A core sheet material was prepared in the same manner as in Example 1 except that a graphite sheet having an average thickness of 1.0 mm and a density of 1000 g / m ³ was used instead of the alumina silica fiber sheet used in Example 1. (Thickness: 1.6 mm), and a case type gasket having the same structure was obtained in the same manner as in Example 1.

Comparative Example 2 A composition comprising 88 parts by weight of asbestos instead of the alumina silica fiber sheet used in Example 1, 10 parts by weight of the NBR emulsion in terms of its solid content, and a small amount of a vulcanizing agent was obtained. Except for using an asbestos sheet having an average thickness of 1.0 mm and a density of 1000 g / m ³ , a steel vest type core sheet material (thickness 1.6 m) was used in the same manner as in Example 1.
m), and a case type gasket having the same structure was obtained in the same manner as in Example 1.

Comparative Example 3 Example 1 was the same as Example 1 except that a sheet having an average thickness of 1.0 mm and a basis weight of 950 g / m ² was obtained by using 60 parts by weight of the NBR emulsion in terms of its solid content. In this way, a steel vest type core sheet material (thickness 1.6 mm) was obtained, and using this, a case type gasket similar to that of Example 1 was obtained.

Comparative Example 4 The average thickness was 1.20 parts by weight of the alumina silica fiber as the component A and 80 parts by weight of the glass fiber as the component E fiber.
A steel vest type core sheet material (thickness: 1.6 mm) was obtained in the same manner as in Example 2 except that a sheet having a thickness of 0 mm and a basis weight of 800 g / m ² was obtained. A similar case gasket was obtained.

Each of the gaskets of Examples 1 to 10 and Comparative Examples 1 to 4 was attached to the inlet of a turbocharger of an actual engine,
A continuous 200 hr durability test was performed. As a result, Example 1
No gas leak was found in any of the gaskets Nos. To 10, but traces of gas leaks were found in all of the comparative examples.

[Brief description of the drawings]

1 is a top view of one embodiment of the present invention, FIG. 2 is a sectional view taken along line XX of FIG. 1, and FIG. 3 is another embodiment taken along line XX of FIG. It is sectional drawing of an example. 1 to 3, reference numeral 1 denotes a core sheet punched and formed into a predetermined gasket shape, reference numerals 2 and 3 denote heat-resistant metal sheets, reference numeral 4 denotes a gas passage port, reference numeral 5 denotes a bolt hole for tightening, and reference numeral 11 denotes a hook. Iron plate.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Yasuo Ijiri 8 Nishinocho, Higashimukaijima, Amagasaki City, Hyogo Prefecture Judge of Mitsubishi Cable Industries, Ltd. JP-A 56-1556437 (JP, A) JP-A 61-171786 (JP, A) JP-A 52-34349 (JP, U)

Claims (1)

(57) [Claims] 1. A core sheet formed into a predetermined gasket shape, wherein at least both front and back surfaces and a side surface of a gas passage opening are covered with a heat-resistant metal sheet, and the core sheet is heated at 700 ° C.
74% by weight of inorganic components whose heating loss per hour is 5% by weight or less
Containing at least 850 ° C. in an atmosphere containing oxygen as an inorganic component and having a residual tensile strength of 8 after heating for 30 minutes.
A heat-resistant gasket comprising at least a sheet layer containing 15% by weight or more of highly heat-resistant fibers of 0% or more.