JPS6059139B2 - Method for manufacturing a gasket made of tetrafluoroethylene resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a method of manufacturing a gasket made of tetrafluoroethylene resin, which is particularly applied to sealing high temperature and high pressure fluids, vacuum fluids, corrosive fluids, and the like.

Technical Background of the Invention and its Problems The encased gasket made of tetrafluoroethylene resin has an asbestos joint sheet or a metal plate in the annular groove on the outer periphery of the tetrafluoroethylene resin outer cover A, as shown in Fig. 4. It is known to connect the annular core body with an adhesive.

In this gasket, when sealing a vacuum fluid, the outer cover A and the core opening are integrally joined by adhesive C, so the outer cover is not drawn inward by the vacuum suction force. For sealing high-temperature fluids, there is no adhesive that can withstand the high temperatures (maximum continuous use temperature 260°C, melting point 32γC) equivalent to that of the tetrafluoroethylene resin jacket, so this gasket effectively utilizes the heat-resistant properties of the jacket. I can't say that. Purpose of the Invention The present invention aims to solve the drawbacks associated with the prior art, and aims to firmly bond the outer cover made of tetrafluoroethylene resin and the core body made of an annular metal plate, and to A packaging made of tetrafluoroethylene resin that does not reduce the adhesive strength between the tetrafluoroethylene resin outer cover and the metal plate even if used for a long time under various conditions, and therefore does not cause peeling problems. The purpose is to provide a method for manufacturing gaskets.

1 Another object of the present invention is to provide a four-sided fluid seal that can be applied not only to a normal inner diameter fluid seal but also to an outer diameter fluid seal that prevents corrosive fluid from leaking from the outer diameter side to the inner diameter side. The object of the present invention is to provide a method for manufacturing an ethylene resin wrapped gasket.

DESCRIPTION OF THE INVENTION The method of manufacturing a gasket made of polytetrafluoroethylene resin according to the present invention is to apply a primer mixed with fluorine resin powder to the upper and lower surfaces of an annular metal plate, and then apply a heat-fusible fluorine resin powder on the wet primer layer. A process of spreading base resin powder and thermally decomposing and sintering it to form an adhesive layer on the upper and lower surfaces of the annular metal plate, and interposing a heat-resistant woven fabric in the adhesive layer or not interposing it. A process of heating and bonding a wide annular tetrafluoroethylene resin jacket protruding from the inside and outside of the metal plate to the metal plate using an adhesive layer, and bonding the protruding parts of the jacket to each other and the protruding parts to the metal plate. The method of manufacturing a gasket made of tetrafluoroethylene resin includes the step of joining the inner and outer surfaces of the gasket with a heated melt of a heat-melting fluororesin.

DETAILED DESCRIPTION OF THE INVENTION I In FIGS. 1 and 2, reference numeral 1 denotes an annular metal plate serving as a core, and adhesive layers 2, 2 are formed on the upper and lower circumferential surfaces of this metal plate.

This adhesive layer 2 is made by applying a primer mixed with fluorine resin powder to the metal plate 1, uniformly scattering the heat-melting fluorine resin powder on the wet primer layer, and applying the heat-melting fluorine resin powder to the metal plate 1. It can be formed when fluororesin is heated and sintered to a temperature higher than that at which it decomposes.

For example, the dispersed heat-melting fluororesin may be a copolymer resin (PFA) of tetrafluoroethylene and perfluoroalkyl vinyl ether, or a copolymer resin of tetrafluoroethylene and hexafluoropropylene (FEP). For powders, etc., a temperature of at least 380'C or higher is required.

In addition, tetrafluoroethylene resin (PTFE), . P.F.A. ．．
As a primer mixed with fluorine resin powder such as FEP, particles are added to an aqueous solution containing phosphoric acid, phosphate, chromic acid, or dichromate, or an organic liquid solution containing heat-resistant resin such as polyimide or silicone resin. Diameter approx. 0.05~
0.5μ. It is made by dispersing fluorine resin powder. (2) Next, wide annular tetrafluoroethylene resin jackets 3, 3 protruding from the inside and outside of the metal plate 1 are integrally heat-bonded to the entire surface of the metal plate 1 using the adhesive layer 2. Further, as shown in FIG. 3, an adhesive layer 2 formed on the upper and lower surfaces of the metal plate 1
Heat-resistant woven fabrics such as glass cloth and asbestos cloth6,6
may be superimposed and the wide tetrafluoroethylene resin outer sheaths 3, 3 may be integrally joined thereon.

In this case, the adhesive layer 2 is bonded to the woven fabric 6 by heating and pressing the adhesive layer.
The outer cover and the metal plate are joined together through the mesh. In addition, as mentioned above, in thermally bonding the metal plate 1 and the outer cover 3 via the adhesive layer 2, it is necessary to heat the metal plate 1 to at least the melting point (32rC) of the tetrafluoroethylene resin.

(2) Finally, the inner and outer protrusions 4, 4 of the outer sheath 3 and the protrusions and the inner and outer surfaces of the metal plate are integrally joined with melts 5, 5 of thermofusible fluororesin.

As a good example, in order to completely cover the metal plate 1 with the outer sheaths 3, 3 made of tetrafluoroethylene resin, the outer sheaths 3, 3 are overlapped on the upper and lower surfaces of the adhesive layer 2 of the metal plate 1, and the inner and outer sides of the outer sheath are protrusions 4, 4
If a heat-melting fluororesin film such as PFBeFEI is interposed between them, and this is placed in a mold and heated and pressurized, the metal plate 1 and the outer sheath 3 are integrated with the adhesive layer 2. At the same time, the heat-melting fluororesin film melts, and the molten material joins the protruding parts 4, 4 of the outer cover, and the molten material flows to the inner and outer surfaces of the metal plate, and the protruding parts and It is possible to join the inner and outer surfaces of metal. Effects of the Invention As described above, the present invention applies a primer mixed with fluororesin powder to a metal plate, sprinkles heat-melting fluororesin powder on this, and forms an adhesive layer by thermally decomposing and sintering this. Since the outer sheath made of tetrafluoroethylene resin is thermally bonded via this adhesive layer, the bonding force is strong and stable bonding force can be maintained at high temperatures.

Then, when the outer sheath made of tetrafluoroethylene resin is widened and the protruding parts protruding to the inside and outside of the metal plate are joined with a heated melt of heat-melting fluorine resin, both the protruding part and the inner and outer surfaces of the metal plate are bonded together. Since they are also bonded in the same way, heat-resistant bonding strength can be obtained.

Therefore, in the gasket according to the present invention, the metal plate and the outer sheath made of tetrafluoroethylene resin are bonded together using an adhesive layer and a heated melt of heat-melting fluororesin, and these have a bonding strength that can withstand high temperatures. It can be applied not only to sealing vacuum fluids, but also to sealing high-temperature, high-pressure fluids whose heat resistance corresponds to that of the polytetrafluoroethylene resin jacket.

In addition, since the inner and outer protrusions of the tetrafluoroethylene resin jacket are joined, it not only provides a normal fluid seal on the inner diameter side, but also prevents corrosive fluid from leaking from the outer diameter side to the inner diameter side. Fluid sealing on the outer diameter side is also possible.

Furthermore, if a woven fabric is interposed between the metal plate and the outer cover, it will be possible to provide cushioning properties to the gasket and improve the sealing effect.In addition, the heated and pressurized adhesive layer will pass through the mesh of the woven fabric and be removed. Since it is bonded to the outer sheath, it has the effect of smoothly joining the metal plate and the outer sheath.

Of course, since the metal plate is entirely covered with a sheath made of tetrafluoroethylene resin, it is also effective as a gasket with excellent electrical insulation properties.

[Brief explanation of drawings]

FIG. 1 is a plan view of a gasket made of polytetrafluoroethylene resin according to the present invention, and FIG. 2 is a sectional view taken along line A-A in FIG.
Fig. 3 is a sectional view of another embodiment of the present invention, and Fig. 4 is a sectional view of a conventional tetrafluoroethylene resin wrapped gasket with reference number 1.
...Metal plate, 2...Adhesive layer, 3...
...Tetrafluoroethylene resin jacket, 4...Protrusion, 5...Heat-melted body of heat-melting fluororesin,
6...Heat-resistant woven fabric.

Claims (1)

[Claims] 1 A primer mixed with fluororesin powder is applied to the upper and lower surfaces of the annular metal plate 1, and the heat-melting fluororesin powder is sprinkled on the wet primer layer, and this is thermally decomposed and sintered to form the annular shape. A step of forming an adhesive layer 2 on the upper and lower surfaces of the metal plate, and forming a wide annular shape protruding from the inside and outside of the metal plate 1 with or without intervening heat-resistant woven fabrics 6, 6 on the adhesive layer 2. A process of integrally heat-bonding the tetrafluoroethylene resin jackets 3, 3 to the metal plate 1 via the adhesive layer 2, and the protrusions 4, 4 of the jackets 3, 3 and the protrusions and the inside and outside of the metal plate. A method for producing a gasket made of polytetrafluoroethylene resin, which comprises the step of joining the side surfaces with heated melts 5, 5 of heat-melting fluororesin.