KR101094149B1 - Inflated graphite gasket and method of preparing same - Google Patents

Abstract

PURPOSE: An expanded graphite gasket and a manufacturing method thereof are provided to secure a sealing performance by reducing porosity of expanded graphite and restricting the penetration of gas. CONSTITUTION: An expanded graphite gasket is as follows. The surface of an expanded graphite sheet(1) is shot-blasted by glass beads. The expanded graphite sheet is located between two sheets of wire meshes. The expanded graphite sheet passes through a pair of compression rollers. A honeycomb pattern is formed in both side surface of the expanded graphite sheet. Clay-dispersed liquid spreads in the expanded graphite sheet.

Description

Inflated Graphite Gasket and Method of Preparing Same

The present invention relates to a novel method for producing expanded graphite gasket, and more particularly, to a method for producing an expanded graphite gasket having a low compression rate and a high recovery rate, and an expanded graphite gasket manufactured by the method. .

In general, a gasket is attached to a joint of various pipes in a petrochemical plant, a nuclear power plant, a thermal power plant, and the like to prevent leakage of fluid flowing through the interior.

As these gaskets, asbestos joint sheet gaskets and non-asbestos joint sheet gaskets have been conventionally used.

These joint sheet gaskets mix asbestos, rock wool, glass fiber, aramid fiber, ceramic fiber and the like as rubber or resin binders, and mix various fillers. For this reason, it is hard at room temperature, has a low compression ratio (small distortion amount), and has a high recovery rate.

For this reason, if the joint seat gasket G is attached to the joint surface of the pipe flange F and the bolt B which connects a flange is tightened (refer FIG. 8), a tightening torque will increase rapidly and will be tightened. And the tightening worker can certainly feel the feeling that the tightening is completed (lock feeling).

As a result, the plurality of bolts can be tightened evenly, and uneven tightening does not occur, and leakage of fluid inside the pipe can be prevented.

As described above, the joint sheet gasket has a low compression ratio and a high recovery rate. Therefore, the joint sheet gasket is excellent in that it can be tightened when attached to the joint surface of the flange, thereby preventing leakage of the fluid.

However, asbestos joint sheet gaskets are currently not manufactured in Korea because of the problem of carcinogenicity of asbestos. On the other hand, although the non-asbestos joint sheet gasket is also used as a substitute for the asbestos joint sheet gasket, there is a problem that it is not suitable for use in a high temperature environment because of low heat resistance (about 260 ℃).

On the other hand, expanded graphite sheet gasket (for example, refer patent document 1) has high heat resistance (about 400 degreeC) compared with a non-asbestos joint sheet gasket, and is suitable for using in a high temperature environment. In addition, it is excellent in chemical resistance and stress relaxation resistance.

However, generally used expanded graphite sheet gasket has a density of expanded graphite of about 0.8 to 1.3 g / cm 3 (reference: JPI-7S-79-1988 (expanded graphite sheet gasket for piping)) and a compression ratio of about 35 to 45 High in%, low recovery rate.

Fig. 9 is a graph showing an example of the relationship between the amount of deformation (mm) and the fastening surface pressure (MPa) with respect to the asbestos joint sheet gasket and the non-asbestos joint sheet gasket and the expanded graphite sheet gasket. In the figure, (A) shows an asbestos joint sheet gasket, (B) shows a non-asbestos joint sheet gasket, and (C) shows an expanded graphite sheet gasket.

In Fig. 9, it can be seen that the expanded graphite sheet gasket has a considerably higher compressibility than the asbestos joint sheet gasket and the non-asbestos joint sheet gasket.

Since the compression ratio is high, when the expanded graphite sheet gasket (G) is attached to the joint surface of the pipe flange (F) and the bolt (B) connecting the flange is tightened, the tightening torque does not increase rapidly, and the tightening operator feels a feeling of locking. It may not be felt clearly, which may cause uneven tightening (see FIG. 10) or compression failure due to excessive tightening.

In addition, since the compression ratio is high, the length of the pipe line is long, such as in petrochemical plants, nuclear power plants, and thermal power plants. There is also.

In order to overcome the shortcomings of the expanded graphite sheet, an expanded graphite sheet having a density of 1.4 g / cm 3 or more, which has a low extrusion rate and a high recovery rate, is suitable for use as a gasket of a pipe flange.

In general, the expanded graphite material has low insulation effect, which allows electricity to pass through, dust is generated well, and graphite is easily adhered to the hand. Thus, the surface is coated with a clay film. The expanded graphite sheet has a disadvantage that it is difficult to coat because the surface of the expanded graphite is not sticking well.

The present inventors have developed a technology for effectively coating a high density expanded graphite sheet of 1.4 g / cm 3 or more as described above, has an insulation effect, dust does not occur well, even when touched by hand, the graphite does not stick well, even waterproof effect It is to develop the expanded graphite clay composite of the present invention.

Patent Document 1: Japanese Patent Application Laid-open No. Hei 10-130626

The present invention has been made to solve the problems of the prior art, to provide an expanded graphite gasket coated on the surface with clay while having a low compression rate and a high recovery rate like a joint sheet gasket.

The present invention relates to a gasket formed by pressurizing expanded graphite, wherein the density of expanded graphite after press molding is 1.4 g / cm 3 or more.

Another embodiment of the present invention is to provide an expanded graphite gasket having a clay coating on the surface of the expanded graphite sheet.

Another embodiment of the present invention is a gasket formed by pressing a laminate having a structure in which a metal plate is sandwiched between two expanded graphite sheets, wherein the expanded graphite has a density of not less than 1.4 g / cm 3 after the pressing. It relates to a gasket made of graphite.

 Another embodiment of the present invention relates to the expanded graphite gasket according to claim 2, wherein a plurality of the laminates are stacked together to be integrated.

 Another embodiment of the present invention relates to the expanded graphite gasket according to claim 3, wherein the plurality of laminates are integrated by a grommet.

 Another embodiment of the present invention relates to the expanded graphite gasket according to any one of claims 1 to 4, wherein the expanded graphite after press forming has a density of 1.6 g / cm 3 or more.

 In another embodiment of the present invention, the plurality of laminates comprise a pair of surface laminates positioned on the top and bottom surfaces of a gasket, and an intermediate laminate sandwiched between the pair of surface laminates. The expanded graphite agent according to claim 3 or 4, wherein the expanded graphite density of the sieve is 1.6 g / cm 3 or more, and the density of the expanded graphite of the surface laminate is 1.4 g / cm 3 or more and less than 1.6 g / cm 3. It is about a gasket.

 Another embodiment of the present invention relates to the expanded graphite gasket according to any one of claims 1 to 6, wherein the expanded graphite is impregnated with antirust oil or antirust agent.

According to another embodiment of the present invention, the surface is coated with a damage preventing agent, wherein the damage preventing agent is composed of inorganic particles and a fixing polymer material for fixing the inorganic particles to the gasket surface. The expanded graphite gasket according to any one of claims 8 to 10.

According to the present invention, since the density of the expanded graphite is 1.4 g / cm 3 or more, the expanded graphite gasket has a high recovery rate and a high recovery rate like the joint sheet gasket.

The compression rate is low and the recovery rate is high, so that when the gasket is attached to the joint surface of the pipe flange and the bolt connecting the flange is tightened, the tightening operator can feel a sense of locking. For this reason, non-uniform tightening phenomenon or excessive tightening does not occur, and it becomes possible to prevent the leakage of the fluid inside a piping and the compression fracture of a gasket.

In addition, since permeation of gas is suppressed by decreasing the porosity of expanded graphite, high sealing performance can be exhibited. In addition, the tensile strength is also excellent.

According to another embodiment of the present invention, since the density of the expanded graphite is 1.4 g / cm 3 or more, the expanded graphite gasket has a high compression ratio and a high recovery rate as well as excellent sealing property and tensile strength as the joint sheet gasket.

In addition, since the metal sheet is sandwiched between two sheets of expanded graphite sheet, the expanded graphite is reinforced by the metal plate, so that the expanded graphite gasket having excellent mechanical strength can be obtained.

According to the other specific example of this invention, since the laminated body is piled up and integrated, the gasket of arbitrary thickness can be obtained easily.

According to another embodiment of the present invention, since a plurality of laminates are integrated by a grommet, a gasket having an arbitrary thickness can be easily obtained, and the porosity of expanded graphite can be reduced by tightening the grommet, thereby providing a sealing property. It becomes possible to raise.

According to another embodiment of the present invention, since the expanded graphite has a density of 1.6 g / cm 3 or more, the expanded graphite gasket is very high at a compression rate of 10% or less and at a recovery rate of more than 50%.

According to another embodiment of the present invention, the plurality of laminates comprises a pair of surface laminates positioned on the top and bottom surfaces of a gasket, and an intermediate laminate sandwiched between the pair of surface laminates, the intermediate laminate The expanded graphite has a density of 1.6 g / cm 3 or more and the surface graphite has a density of 1.4 g / cm 3 or more and less than 1.6 g / cm 3, so that the intermediate laminate has a low compression ratio and a high recovery rate. At the same time, the surface layered product provides an expanded graphite gasket having excellent affinity and high sealing performance.

According to another embodiment of the present invention, since the antirust oil or the antirust agent is impregnated in the expanded graphite, the voids inside the expanded graphite are filled with the antirust oil or the antirust agent, thereby improving the sealing property of the gasket.

According to another embodiment of the present invention, since the surface is covered with a clay film, an expanded graphite gasket having excellent heat resistance, corrosion resistance, gas barrier property, and acid resistance is obtained.

According to another embodiment of the present invention, since the surface is coated with a damage preventing agent, and the damage preventing agent is composed of inorganic particles and a fixing polymer material for surface fixing the inorganic particles, an expanded graphite gasket having excellent damage resistance Becomes

1 is a view showing a first embodiment of an expanded graphite gasket according to the present invention, where (a) is a plan view and (b) is a sectional view.
2 is a graph showing the relationship between the density of expanded graphite and the compression recovery rate.
3 is a graph showing a relationship showing the relationship between the density (g / cm 3) and the stress relaxation ratio (%) of expanded graphite under 200 ° C. heating conditions.
4 is a cross-sectional view showing another embodiment of the expanded graphite gasket according to the present invention, where (a) shows a second embodiment and (b) shows a third embodiment.
Fig. 5 is a cross-sectional view showing still another embodiment of the expanded graphite gasket according to the present invention, wherein (a) shows a fourth embodiment and (b) shows a fifth embodiment.
FIG. 6 is a graph showing compression restoration test results for the expanded graphite gaskets of Examples 1 and 2. FIG.
Fig. 7 is a graph showing the sealing test results for the expanded graphite gaskets of Examples 3 to 6;
Fig. 8 is an explanatory diagram showing a state when a joint seat gasket is attached to a joint surface of a pipe flange and the bolt connecting the flange is tightened.
9 is a graph showing an example of the relationship between the deformation amount (mm) and the tightening surface pressure (MPa) with respect to the asbestos joint sheet gasket and the non-asbestos joint sheet gasket and the expanded graphite sheet gasket.
Fig. 10 is an explanatory diagram showing a state when the expanded graphite sheet gasket is attached to the joint surface of the pipe flange and the bolt connecting the flange is tightened.

EMBODIMENT OF THE INVENTION Hereinafter, preferred embodiment of the expanded graphite gasket which concerns on this invention is described, referring drawings.

1 is a view showing a first embodiment of an expanded graphite gasket according to the present invention, where (a) is a plan view and (b) is a sectional view.

The expanded graphite gasket according to the first embodiment is a gasket formed by press-molding expanded graphite, and the density of expanded graphite after press molding is 1.4 g / cm 3 or more, and more preferably 1.6 g / cm 3 or more.

In the expanded graphite gasket according to the present invention (including all the embodiments described later), the density of the expanded graphite is set higher than that of the conventional expanded graphite gasket.

That is, while the density of expanded graphite in the conventional expanded graphite gasket is about 0.8-1.3 g / cm 3, the density of expanded graphite in the expanded graphite gasket according to the present invention is 1.4 g / cm 3 or more, more preferably. 1.6 g / cm 3 or more.

In general, in the case of a low density expanded graphite sheet, it is possible to spray clay particles directly onto the expanded graphite sheet, but in the case of a high density expanded graphite sheet of 1.4 g / cm 3 or more, the viscosity is very poor, It is not possible to coat by direct spraying. Therefore, the coating according to the order of the coating method of the expanded graphite sheet according to the present invention as follows.

The higher the density, the lower the compression rate and the higher the recovery rate.However, when the density is increased to 1.54 g / cm3 or more, it is very difficult to manufacture the expanded graphite sheet because it requires pressurization to 400-600 kg / cm2. In terms of productivity, the economical efficiency of the expanded graphite is preferably 1.4 to 1.54 g / cm 3.

According to the coating method of the expanded graphite sheet according to the present invention, first, the surface of the expanded graphite sheet 1 is subjected to shot blast treatment with glass beads having a diameter of 0.5 to 0.8 mm. By such a treatment, the smooth expanded graphite sheet surface becomes an irregular rough surface. The shot blasting process can be easily carried out by those skilled in the art.

The expanded graphite sheet blasted on the surface as described above is then placed between the two sheets of mesh-shaped mesh wire mesh and passed between the compression rollers to process both surfaces of the expanded graphite sheet into a honeycomb pattern. . The mesh wire mesh used for the processing has a diameter of the wire constituting the wire mesh in the range of about 0.08 ~ 0.1 mm, and uses a mesh wire mesh having a density of 250 ~ 300 mesh (mesh). The pressure of the compression roller can be easily carried out by those skilled in the art to which the present invention pertains. After setting the distance between the compression rollers to be equal to the thickness of the expanded graphite sheet, the expanded graphite sheet is placed between two mesh mesh meshes and passed between the compression rollers. According to the honeycomb pattern is formed.

By blasting the surface and processing into a honeycomb, the expanded graphite sheet is improved in adhesion to the coating film so as to be suitable for coating the clay dispersion. When the clay dispersion is laminated on the surface of the expanded graphite sheet treated by the screen printing method, the expanded graphite clay composite coated with the clay film is completed.

As a clay dispersion liquid laminated | stacked on the expanded graphite sheet surface, the thing in which the clay or the additive which has a clay as a main component is disperse | distributed or melt | dissolved in the solvent which uses water as a main component is used. As the clay used in the clay dispersion, natural clay, synthetic clay, modified clay, etc., in which the solid content is contained in a proportion of 3 to 15% by weight may be used.

As the additive of the clay, cellulose, phenol resin, alkyd resin, urea resin, cellulose acetate, vinyl acetate resin, acrylic resin, styrene resin, vinyl chloride resin, melamine resin, polyethylene, polyurethane resin, vinylidene chloride resin, poly Amide resin, unsaturated polyester, silicon resin, acrylonitrile-styrene resin, fluorine resin, epoxy resin, diallyl phthalate resin, acrylonitrile-butadiene-styrene resin, polyethylene terephthalate, polypropylene, polycarbonate, polyacetal, One kind or more than one kind of polyamide, polysulfone, polyphenylene ether, polybutylene terephthalate, polyether sulfone, liquid crystal polymer, polyphenylene sulfide and polyetheramide may be used in combination.

In addition, not only water but an organic solvent may be used as the solvent in the clay dispersion.

Graphite clay composite material prepared in the above manner has an insulating effect by coating the surface of the graphite having a conductive property with a clay film having a non-conductive property. Also, dust does not occur well, and graphite does not stick to hands even if touched by hand. It is also suitable for use as sealing materials for joint seats, gaskets, and packings because of its improved waterproofing effect.

2 is a graph showing the relationship between the density (g / cm 3) and the compression recovery rate (%) of expanded graphite.

As shown, the expanded graphite has a lower compression ratio and a higher recovery rate as the density increases.

More specifically, the compression ratio and the recovery rate are the same in the vicinity of the density of the expanded graphite exceeding 1.3 g / cm 3, and when it is 1.4 g / cm 3 or more, the recovery rate is higher than the compression rate. For this reason, when the density of expanded graphite is made 1.4 g / cm <3> or more, like a joint sheet gasket, it becomes a expanded graphite gasket which has a low compression rate and a high recovery rate, More specifically, a recovery rate is higher than a compression rate.

In addition, since the sealing property and the tensile strength increase when the density of expanded graphite increases, the density of expanded graphite is made 1.4 g / cm <3> or more, and it becomes an expanded graphite gasket excellent also in sealing property and tensile strength.

Moreover, when the density of expanded graphite is 1.6 g / cm <3> or more, it becomes the expanded graphite gasket which is very low in the compression rate to several ten% or less, and very high in the recovery rate more than 50%.

Here, when the density of expanded graphite exceeds 1.75 g / cm 3, the compressibility becomes almost constant. For this reason, in this invention, the upper limit of the density of expanded graphite can be set to 1.75 g / cm <3>. In this case, the setting range of density is 1.4-1.75 g / cm <3>, Preferably it is 1.6-1.75 g / cm <3>.

3 is a graph showing the relationship between the density (g / cm 3) and the stress relaxation rate (%) of expanded graphite under 200 ° C. heating conditions.

Although the stress relaxation rate of a general non-asbestos joint sheet is several% at normal temperature, it increases to 15 to 25% at 200 degreeC.

As shown in Fig. 3, the expanded graphite has a smaller stress relaxation rate than the non-asbestos joint sheet even when the density is small (1.1 g / cm 3), but when the density increases, the stress relaxation rate becomes smaller, and the tightening surface pressure is 20 MPa. Has a density of 1.54 g / cm 3 and almost no stress relaxation.

From this fact, it can be said that the expanded graphite gasket having a density of 1.4 g / cm 3 or more of expanded graphite has excellent stress relaxation performance under high temperature conditions.

4 is a cross-sectional view showing another embodiment of the expanded graphite gasket according to the present invention, where (a) shows a second embodiment and (b) shows a third embodiment. In addition, a top view is the same as that of 1st Embodiment.

The expanded graphite gasket according to the second and third embodiments is a gasket formed by press-molding a laminate having a structure in which a metal plate 2 is sandwiched between two expanded graphite sheets 1, and the expanded graphite after press molding. The density is at least 1.4 g / cm 3, more preferably at least 1.6 g / cm 3.

As a material of the metal plate 2, iron, copper, a copper alloy, stainless steel, aluminum, etc. can be illustrated, but it is most preferable to use stainless steel from a corrosion resistance viewpoint.

The shape of the metal plate 2 differs from that of 2nd Embodiment and 3rd Embodiment.

Specifically, the thing of 2nd Embodiment consists of a thin plate with the metal plate 2 flat, and the thing of 3rd Embodiment consists of a hook plate in which the metal plate 2 protrudes up and down.

According to the expanded graphite gaskets according to the second and third embodiments, since the strength of the expanded graphite is reinforced by the metal plate 2, the expanded graphite gasket having excellent mechanical strength can be obtained.

Although the thickness of the expanded graphite sheet 1 and the metal plate 2 is not particularly limited, in the second embodiment, for example, the thickness of the expanded graphite sheet 1 is 0.75 mm and the thickness of the metal plate 2 is 0.05 mm. You can do After adhering them to each other, the expanded graphite gasket of the second embodiment can be obtained by press molding and the density of the expanded graphite to be 1.4 g / cm 3 or more.

In the third embodiment, for example, the thickness of the expanded graphite sheet 1 may be 0.75 mm, and the thickness of the metal plate 2 may be 0.1 mm. After adhering these to each other, the expanded graphite gasket of the third embodiment can be obtained by press molding and the density of the expanded graphite to be 1.4 g / cm 3 or more.

Fig. 5 is a cross-sectional view showing still another embodiment of the expanded graphite gasket according to the present invention, wherein (a) shows a fourth embodiment and (b) shows a fifth embodiment. In addition, a top view is the same as that of 1st Embodiment.

The expanded graphite gaskets according to the fourth and fifth embodiments include a laminate 3 having a structure in which a metal plate 2 is sandwiched between two expanded graphite sheets 1 (three in the illustrated example). ), They are integrated by the grommet 4.

The plurality of laminates 3 are composed of a pair of surface laminates 3a positioned on the top and bottom surfaces of the gasket, and an intermediate laminate 3b sandwiched between the pair of surface laminates 3a. have. Although the intermediate | middle laminated body 3b is one piece in the example shown, you may make it multiple sheets.

In the expanded graphite gasket according to the fourth embodiment, the laminated body 3 having a structure in which a metal plate 2 made of flat thin plates is sandwiched between two expanded graphite sheets 1 is sandwiched by a grommet 4. It is integrated.

The expanded graphite gasket according to the fifth embodiment includes two expanded graphite sheets between two laminated bodies 3 having a structure in which a metal plate 2 made of flat thin plates is sandwiched between two expanded graphite sheets 1. It overlaps and integrates three pieces by the grommet 4 so that the one laminated body 3 which has the structure which pinched | interposed the metal plate 2 which consists of the hook plate which has a projection up and down between (1) is inserted.

As a material of the metal plate 2, iron, copper, a copper alloy, stainless steel, aluminum, etc. can be illustrated, but it is most preferable to use stainless steel from a corrosion resistance viewpoint.

The grommet 4 is fitted to the inner diameter portion of the ring-shaped gasket in the illustrated example, but may be fitted to both the inner diameter portion and the outer diameter portion.

The grommet 4 is formed from stainless steel plates, such as SUS304, SUS316, and SUS316L, and it is preferable that the thickness is 0.2 mm or less (preferably 0.1 mm).

By setting the thickness of the grommet 4 to 0.2 mm or less, the affinity of the gasket surface becomes favorable.

The gasket radial length of the grommet 4 may be the same on the gasket surface side and the back side as shown in FIG. 5 (a), or may be different as shown in FIG. 5 (b). In other cases, the operator can easily distinguish between the gasket surface and the back side, or the grommet does not fall out even when the gasket is displaced when installed on the joint surface of the pipe extending in the horizontal direction (horizontal direction). There is this.

In the 4th and 5th embodiment demonstrated above, you may use the other method which does not use the grommet 4 as a method of integrating the several laminated body 3.

As another method for integration, a method such as pressing or bonding can be used.

The adhesive agent used when integrated by adhesion is not specifically limited, Various adhesives, such as a phenol type, a rubber type, and an organic type, can be selected suitably and can be used.

In this invention, although the density of expanded graphite of the surface laminated body 3a and the intermediate | middle laminated body 3b may be made the same, the density of the expanded graphite of the surface laminated body 3a is the density of the expanded graphite of the intermediate laminated body 3b. It is preferable to make it smaller. Specifically, the density of expanded graphite of the intermediate laminate 3b is preferably 1.6 g / cm 3 or more, and the density of expanded graphite of the surface laminated body 3a is preferably 1.4 g / cm 3 or more and less than 1.6 g / cm 3. Do.

Thereby, the intermediate | middle laminated body 3b exhibits the low compression rate and the high recovery rate, and the expanded graphite gasket which is excellent in affinity and high sealing property is exhibited by the surface laminated body 3a. do.

In the present invention, in the gaskets of all the embodiments described above, the expanded graphite may be impregnated with antirust oil or antirust agent.

By impregnating antirust oil or an antirust agent with expanded graphite, the space | gap inside an expanded graphite is filled with antirust oil or an antirust agent, and the sealing property of a gasket can be improved.

In the present invention, the surface (upper and lower surface) may be covered with a clay film in the gaskets of all the embodiments described above.

As the clay constituting the clay film, at least one of natural clay, synthetic clay and modified clay can be used.

More specifically, mica, vermiculite, montmorillonite, baydelite, saponite, hectorite, stevensite, magadiite, aira light, kanemite, illite, sericite, At least one of nontronite is suitably used.

The clays used for the modified clays are natural or synthetic, suitably, for example, mica, vermiculite, montmorillonite, baydelite, saponite, hectorite, stevensite, margotite, airite, cannemite, il One or more of light, sericite, more suitably, any one of these natural or synthetic or mixtures thereof are exemplified.

Examples of the organic cation used in the modified clay include those containing quaternary ammonium cation or quaternary phosphonium cation. At this time, the structure which makes the organic cation composition in modified clay into less than 30 weight% can be employ | adopted.

Moreover, in this invention, what made the cyrilizing agent react with modified clay can also be used. In this case, it is possible to employ a configuration in which the silylating agent composition is less than 30% by weight relative to the total weight of the clay and the silylating agent.

Examples of the organic material included in the modified clay include quaternary ammonium cation, quaternary phosphonium cation, imidazolium cation, and pyridinium cation. Although it does not specifically limit as a quaternary ammonium cation, The dimethyl octadecyl type, the dimethyl stearyl benzyl type, and the trimethyl stearyl type are illustrated. Also, as similar organic substances, quaternary phosphonium cations are exemplified. These organic substances are introduced into the clay by ion exchange of the raw clay.

The silylating agent contained in the modified clay is not particularly limited, but may be methyltrimethoxysilane, methyltriethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxy Silane, dodecyl trimethoxysilane, and octadecyl trimethoxysilane can be illustrated.

The thickness of a clay film is 3-100 micrometers, for example, Preferably it is set to 3-30 micrometers.

The gas barrier performance of the clay membrane is less than 0.1 cc / m 2 · 24 hr · atm of oxygen permeability and less than 0.1 cc / m 2 · 24 hr · atm of hydrogen permeability at a thickness of 30 μm, and room temperature of helium, hydrogen, oxygen, nitrogen, and air. The gas transmission coefficient at is less than 3.2 × 10 ⁻¹¹ cm 2 s ⁻¹ cmHg ⁻¹ .

In addition, the degree of ordering is that the ordering coefficient is 2 × 0 ^-11 cm / s or less, excellent flexibility, and the structure does not change even at a high temperature of 250 to 600 ° C.

Moreover, in this invention, in the gasket of all embodiment demonstrated above, you may coat the surface (upper and lower surface) with a damage inhibitor.

The damage preventing agent is composed of inorganic particles and a fixing polymer material for fixing the inorganic particles to the gasket surface.

The kind of the inorganic particles is not particularly limited as long as it is excellent in heat resistance. Those having the above heat resistance are suitably used.

Specifically, silica, alumina, glass, aluminosilicate, shiras balloon, kaolin, clay, talc, calcium carbonate, graphite, mica, boron nitride, molybdenum disulfide, aluminum sulfate, barium sulfate, calcium sulfate, oxide It is preferable to use one or two or more selected from magnesium, magnesium silicate, calcium silicate, potassium titanate, diatomaceous earth and vermiculite.

Among the inorganic particles described above, in the present invention, it is preferable to use one or two or more of silica, alumina, talc, kaolin, clay, and graphite.

This is because these inorganic particles are relatively easy to obtain and are excellent in general-purpose handling properties.

It is preferable that it is 0.1-30 weight% with respect to whole damage inhibitor, and, as for the compounding quantity of an inorganic particle, it is more preferable that it is 0.5-10 weight%.

If the blending amount is less than 0.1% by weight, the damage preventing effect cannot be sufficiently obtained. If the blending amount is more than 30% by weight, the damage preventing layer becomes too thick and the sealability may be impaired.

It is preferable that it is 0.1-30 micrometers, and, as for the particle diameter of an inorganic particle, it is more preferable that it is 0.5-20 micrometers.

If the particle size is less than 0.1 μm, the handleability decreases and the manufacturing cost increases due to the occurrence of coagulation of particles or scattering during mixing. If the particle size exceeds 30 μm, the gap between particles increases and the sealing property may be damaged. It is not preferable in either case.

Thermosetting resins, thermoplastic resins, higher fatty acids and the like are suitably used as the fixing polymer material, but the cellulose polymer material is most preferably used. This is because the inorganic particles have excellent fixability, and are excellent in film strength, flexibility, solubility, and safety.

Specific examples of the cellulose polymer include ethyl methyl cellulose, cellulose acetate, methyl cellulose, and ethyl cellulose.

It is preferable that it is 0.01-10 weight% with respect to the damage inhibitor whole quantity, and, as for the compounding quantity of the fixing polymeric material, it is more preferable that it is 0.01-5 weight%.

If the blending amount is less than 0.01% by weight, the fixation of the coated inorganic particles may be poor, and the fall prevention function may be reduced, and the damage prevention function may be lowered. Neither case is preferable.

It is preferable that the compounding ratio (weight ratio) of an inorganic particle and a high molecular material for fixation is the high molecular material for fixation when it is set to 1 for inorganic particle to be 0.01-2.0.

If the ratio of the high molecular material for fixation when the inorganic particles is 1 is less than 0.01, the fixation of the coated inorganic particles may deteriorate easily, and the damage prevention function may be impaired. Since it cannot be, neither case is preferable.

[Example]

Hereinafter, by showing examples of the expanded graphite gasket according to the present invention, the effects of the present invention will be more clearly shown. However, the present invention is not limited to the following examples.

<Examples 1-6: The gasket consisting only of expanded graphite>

A gasket composed only of expanded graphite was fabricated and subjected to a compression restoration test and a leak test.

1. Compression Restoration Test

(Example 1)

An expanded graphite sheet having a thickness of 3.05 mm and a density of 1.0 g / cm 3 was press-molded to produce a compressed sheet having a thickness of 1.85 mm and a density of 1.65 g / cm 3. The surface of the expanded graphite sheet was shot blasted with glass beads having a diameter of 0.7 mm, and between two sheets of mesh wire mesh having a diameter of about 0.09 mm and a density of 270 mesh. The expanded graphite sheet was placed and passed between compression rollers to process both surfaces of the expanded graphite sheet into a honeycomb pattern, and a clay dispersion was applied to the expanded graphite sheet by screen printing.

(Example 2)

An expanded graphite gasket was produced in the same manner as in Example 1 except that an expanded graphite sheet having a thickness of 3.18 mm and a density of 1.0 g / cm 3 was press-molded to produce a compressed sheet having a thickness of 1.83 mm and a density of 1.74 g / cm 3. .

About the expanded graphite gasket of Examples 1 and 2, the compression restoration test was done in accordance with the method prescribed | regulated to EN13555, and the relationship between deformation (mm) and tightening surface pressure (MPa) was measured.

The results are shown in FIG.

As shown in FIG. 6, it was confirmed that the expanded graphite gaskets of Examples 1 and 2 had a low compression ratio and a high recovery rate, and had compression restoring characteristics close to those of the joint sheet gasket shown in FIG. 9.

2. Leak test

(Example 3)

An expanded graphite gasket was produced in the same manner as in Example 1 except that the expanded graphite sheet having a thickness of 2.0 mm and a density of 1.0 g / cm 3 was press-molded to produce a compressed sheet having a thickness of 1.72 mm and a density of 1.41 g / cm 3. .

(Example 4)

An expanded graphite gasket was produced in the same manner as in Example 1 except that the expanded graphite sheet having a thickness of 2.0 mm and a density of 1.0 g / cm 3 was press-molded to produce a compressed sheet having a thickness of 1.60 mm and a density of 1.54 g / cm 3. .

(Example 5)

An expanded graphite gasket was manufactured in the same manner as in Example 1 except that an expanded graphite sheet having a thickness of 2.0 mm and a density of 1.0 g / cm 3 was press-molded to produce a compressed sheet having a thickness of 1.53 mm and a density of 1.67 g / cm 3. .

(Example 6)

An expanded graphite gasket was produced in the same manner as in Example 1 except that an expanded graphite sheet having a thickness of 2.0 mm and a density of 1.0 g / cm 3 was press-molded to produce a compressed sheet having a thickness of 1.37 mm and a density of 1.74 g / cm 3. .

The expanded graphite gaskets of Examples 3 to 6 were subjected to a sealing test using a gasket sealing tester (manufactured by Amtec, Germany, TA-LOFT recognizer) according to the method specified in EN13555, and tightened. The relationship between the surface pressure (MPa) and the leakage amount (atmcc / s) was measured. The internal pressure was helium 1 MPa.

The results are shown in FIG.

As shown in Fig. 7, it was confirmed that the leakage amount decreases as the expanded graphite density increases.

<Examples 7 to 10: Gaskets made of expanded graphite and metal plate>

A gasket made of expanded graphite and a metal plate was fabricated, and subjected to a compression restoration test and a leak test.

(Examples 7-9)

Three laminates each having a thickness of 0.7 mm and an expanded graphite sheet having a density of 1.0 g / cm &lt; 3 &gt; adhered to both surfaces of a flat thin plate of a SUS316 product having a thickness of 0.05 mm were bonded together to obtain a total thickness of 4.5 mm. The expanded graphite gaskets of Examples 7, 8, and 9 were produced in the same manner as in Example 1, except that they were press-molded to have thicknesses of 3.0 mm, 2.7 mm, and 2.5 mm.

About the expanded graphite gasket of Examples 7-9, the compression rate (%), recovery rate (%), and leakage amount (atm * cc / s) were measured by the method similar to Examples 1-6. In addition, gasket tightening surface pressure in leak amount measurement was 20 Mpa, and internal pressure was helium 1 Mpa.

The measurement results are shown in Table 1.

Density (g / cm 3) Compression ratio Recovery rate Leakage Example 7 1.54 10.2 61.3 1.83 × 10 ^-5 Example 8 1.70 7.2 78.8 1.43 × 10 ^-5 Example 9 1.82 5.8 78.8 8.12 × 10 ^-6

As shown in Table 1, all of the expanded graphite gaskets of Examples 7 to 9 had a low compression ratio, a high recovery rate, excellent sealing properties, and high density, these characteristics became more remarkable.

(Example 10)

An expanded graphite sheet having a thickness of 0.75 mm and a density of 1.0 g / cm3 was bonded to both sides of a hook plate of a SUS316 product having a thickness of 0.10 mm, and 0.75 mm of a thickness and 1.0 g of a density were provided on both sides of a flat sheet of a SUS316 product having a thickness of 0.05 mm. The laminated bodies of thickness 1.5mm which adhere | attached the / cm <3> expanded graphite sheet | seat further adhere | attached each other, and were made into total thickness 4.5mm. The expanded graphite gasket of Example 10 was prepared in the same manner as in Example 1, except that the mold was pressed under a thickness of 2.7 mm.

About the expanded graphite gasket of Example 10, the compression rate (%), recovery rate (%), and leakage amount (atm * cc / s) were measured by the method similar to Examples 7-9. In addition, gasket tightening surface pressure in leak amount measurement was 20 Mpa, and internal pressure was helium 1 Mpa.

The measurement results are shown in Table 2.

Density (g / cm 3) Compression ratio Recovery rate Leakage Example 10 1.70 7.80 68.4 2.31 × 10 ^-5

As shown in Table 2, the expanded graphite gasket of Example 10 had a low compression ratio, a high recovery rate, and an excellent sealing property.

The expanded graphite gasket according to the present invention can be suitably used as a substitute for conventional asbestos joint sheet gaskets at joints of various pipes in petrochemical plants, nuclear power plants, thermal power plants, and the like.

Simple modifications and variations of the present invention can be readily used by those skilled in the art, and all such variations or modifications can be considered to be included within the scope of the present invention.

1: expanded graphite sheet 2: metal plate
3: laminate 3a: surface laminate
3b: intermediate stack 4: grommets

Claims (9)

delete delete delete The surface of the expanded graphite sheet produced by pressing the expanded graphite is shot blasted with glass beads beads; Placing the treated expanded graphite sheet between two mesh mesh meshes and passing them through a pair of compression rollers to form a honeycomb pattern on both surfaces of the expanded graphite sheet; And applying a clay dispersion to the processed expanded graphite sheet, wherein the mesh wire mesh has a wire diameter of 0.08 to 0.1 mm and a diameter of 250 to 300 mesh. It has a density, The manufacturing method of expanded graphite gasket characterized by the above-mentioned.
The method for producing an expanded graphite gasket according to claim 4, wherein the expanded graphite after press forming has a density of 1.4 to 1.54 g / cm 3.
The method for producing an expanded graphite gasket according to claim 4, wherein the expanded graphite sheet is a laminate having a structure in which a metal plate is sandwiched between two expanded graphite sheets.
The method for producing an expanded graphite gasket according to claim 6, wherein a plurality of the laminates are stacked and integrated.
The method for producing an expanded graphite gasket according to claim 7, wherein the plurality of laminates are integrated by a grommet.
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