JP6652321B2 - Fluoroplastic wrapped gasket - Google Patents

Description

  The present invention relates to a fluorine resin wrapped gasket. More specifically, for example, the present invention relates to a fluororesin wrapping gasket that can be suitably used as a pipe sealing material or the like at a connection between pipes, and a method of manufacturing the same.

  As a gasket excellent in chemical resistance, a gasket made of fluororesin has been proposed. However, a gasket made of a fluororesin has a disadvantage that stress relaxation at a high temperature is large.

  As a gasket excellent in heat resistance and chemical resistance, a wrapping gasket that has a core material and the outer periphery of the core material is covered with a sheath made of a fluororesin film is known. The wrapping gasket is used, for example, as a pipe sealing material at a connection between pipes. However, the wrapped gasket is inferior in workability when mounted on a pipe or the like because the outer skin is easily peeled off when connecting the pipes, and the content in the pipe is determined by the gap between the outer skin and the connection portion of the pipe. Things may leak.

  As a gasket capable of suppressing the peeling of the envelope of the wrapped gasket, the gasket is composed of an annular core material and a fluorocarbon resin outer material covering the core material, wherein the outer material is an inner peripheral surface of an upper surface of the annular core material, There has been proposed a gasket that continuously covers the inner peripheral surface and the inner peripheral surface of the bottom surface and is partially joined to the upper surface and the bottom surface of the annular core material (for example, refer to claim 5 of Patent Document 1). However, in the gasket, the outer shell material is joined to the upper surface and the bottom surface of the annular core material by a substantially linear stitch, so that not only a complicated suturing operation is required to manufacture the gasket, but also the annular When the core is made of a fluororesin, it is difficult to sew the annular core with the outer skin because the annular core is hard. Therefore, it has been proposed to use expanded porous polytetrafluoroethylene for the upper and lower surfaces of the annular core material in order to facilitate the suturing of the outer shell material of the gasket and the upper and lower surfaces of the annular core material (for example, However, since the gasket uses porous polytetrafluoroethylene, there is a disadvantage that stress relaxation is remarkable.

JP 2006-258212 A

  The present invention does not require the use of a porous fluororesin, and the annular core and the outer skin covering the upper surface, the inner peripheral surface, and the lower surface of the core are integrated without suturing, thereby reducing stress. It is an object of the present invention to provide a wrapping gasket which is small and has excellent sealing properties. Further, the present invention does not require the use of a porous fluororesin, and the annular core and the outer skin covering the upper surface, the inner peripheral surface, and the lower surface of the core are integrated without suturing. It is another object of the present invention to provide a method of manufacturing a wrapping gasket which can efficiently manufacture a wrapping gasket having small stress relaxation and excellent sealing properties.

The present invention
(1) A wrapping gasket having an annular core and an outer cover covering an upper surface, an inner peripheral surface and a lower surface of the core, wherein the core is a fluororesin gasket made of a fluororesin containing a filler. The filler is a particulate filler having an average particle diameter of 1 to 100 μm , and the content of the particulate filler in the fluororesin gasket is 3 to 80% by mass ; The filler is carbon-based particles, clay, silica particles, alumina particles, silicon carbide particles, inorganic particles selected from the group consisting of glass particles and metal particles, the outer skin is a non-porous fluororesin outer skin, The fluororesin gasket and the outer cover are fused and integrated, and the thermocompression bonding strength between the fluororesin gasket and the outer cover is 0.5 N / mm or more. Look gasket,
(2) The fluororesin wrapped gasket according to (1), wherein the outer skin contains a filler.
(3) A method for producing a wrapping gasket having an annular core and an outer cover covering an upper surface, an inner peripheral surface, and a lower surface of the core, wherein the core has an average particle diameter of 1 to 100 μm. A filler is contained at a content of 3 to 80% by mass , and the particulate filler is selected from the group consisting of carbon-based particles, clay, silica particles, alumina particles, silicon carbide particles, glass particles, and metal particles. using Oh Ru fluororesin gasket inorganic particles, the use of a non-porous fluorine resin skin as outer skin, covering the top surface and the inner peripheral surface and the lower surface of the fluororesin gasket in the outer skin, and the fluororesin gasket Producing a fluororesin wrapped gasket, wherein the outer cover is fused and integrated by thermocompression bonding, and the thermocompression bonding strength between the gasket and the outer skin is adjusted to 0.5 N / mm or more. Methods, and (4) a method for producing a fluororesin covered gasket according to the said outer skin contains a filler (3).

  According to the present invention, it is not necessary to use a porous fluororesin as in the related art, and the annular core and the outer skin covering the upper surface, the inner peripheral surface, and the lower surface of the core do not need to be sewn. A wrapping gasket that is integrated, has low stress relaxation, and has excellent sealing properties between the core and the outer skin is provided. Further, according to the present invention, it is not necessary to use a porous fluororesin, and the annular core and the outer skin that covers the upper surface, the inner peripheral surface, and the lower surface of the core are integrated without being stitched. The present invention provides a method for manufacturing a wrapping gasket capable of efficiently manufacturing a wrapping gasket which is reduced in stress, has small stress relaxation, and has excellent sealing properties between a core and an outer skin.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing which shows one Embodiment of the fluorine resin wrapping gasket of this invention. It is a schematic sectional drawing which shows another embodiment of the fluororesin wrapping gasket of this invention.

  As described above, the fluororesin wrapped gasket of the present invention is a wrapped gasket having an annular core and an outer skin covering the upper surface, the inner peripheral surface, and the lower surface of the core, wherein the core contains a filler. A fluororesin gasket made of a fluororesin, wherein the outer skin is a fluororesin outer skin, and the fluororesin gasket and the fluororesin outer skin are thermocompression-bonded.

  The fluororesin wrapped gasket of the present invention, for example, covers the upper surface, inner peripheral surface, and lower surface of the fluororesin gasket with a fluororesin outer skin, and integrates the fluororesin gasket and the fluororesin outer skin by thermocompression bonding. Can be manufactured.

  The fluororesin gasket used as the annular core is made of a fluororesin containing a filler. The fluororesin gasket can be manufactured, for example, by molding a gasket-forming resin composition containing a fluororesin and a filler into a sheet having a predetermined shape.

  Examples of the fluororesin that can be used for the fluororesin gasket include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkylvinylether copolymer (PFA), and tetrafluoroethylene-hexafluoropropylene copolymer ( FEP), tetrafluoroethylene-ethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), chlorotrifluoroethylene-ethylene copolymer (ECTFE), and the like. The invention is not limited only to such an example. These fluororesins may be used alone or in combination of two or more. Among these fluororesins, polytetrafluoroethylene (PTFE) is preferable because of excellent moldability and workability.

  Fillers can be broadly classified into inorganic fillers and organic fillers. The inorganic filler and the organic filler may be used alone or in combination.

  As the inorganic filler, for example, graphite particles, expanded graphite particles, carbon black particles, carbon-based particles such as activated carbon particles, talc, clay, mica particles, magnesium carbonate particles, calcium carbonate particles, magnesium oxide particles, silica particles, alumina particles Inorganic particles such as particles, silicon carbide particles, silicon nitride particles, boron nitride particles, calcium silicate particles, aluminum silicate particles, calcium sulfate particles, barium sulfate particles, glass particles, metal particles; carbon nanotubes, glass fibers, carbon fibers, rock Examples thereof include inorganic fibers such as wool, ceramic fibers, and zirconia fibers, but the present invention is not limited to only such examples. These inorganic fillers may be used alone or in combination of two or more.

  As the organic filler, for example, polyester resin particles, polyamide resin particles, acrylic resin resin particles, polystyrene resin particles, vinyl chloride resin resin particles, vinyl acetate resin resin particles, phenol resin resin particles, epoxy Resin particles such as resin-based resin particles, silicone-based resin particles, polyurethane-based resin particles, and polyphenylene sulfide (PPS) particles; resin fibers such as aramid fiber, fluororesin fiber, polyester fiber, nylon fiber, acrylic resin fiber, and polyolefin fiber. However, the present invention is not limited to only such examples. These organic fillers may be used alone or in combination of two or more.

  The average particle diameter of the particulate filler is not particularly limited, but is preferably 1 μm or more, more preferably 2 μm or more, and still more preferably 3 μm or more, from the viewpoint of improving the mechanical strength of the fluororesin gasket. From the viewpoint of improving the stress relaxation of the resin gasket, the thickness is preferably 100 μm or less, more preferably 80 μm or less, and still more preferably 30 μm or less. The average particle diameter of the particulate filler means a volume average particle diameter measured by a Coulter counter method. In the Coulter counter method, an electrolyte in which a filler is suspended is passed through pores (apertures), and a change in a voltage pulse generated in proportion to the volume of the filler at that time is read to measure a particle diameter. The method is to measure the height of the voltage pulse one by one to obtain a volume distribution histogram of the filler.

The fiber length of the fibrous filler is not particularly limited, but is usually preferably 15 mm or less, more preferably 3 to 10 mm, from the viewpoint of improving the mechanical strength and stress relaxation of the fluororesin gasket.

  From the viewpoint of improving the mechanical strength of the fluororesin gasket, the content of the filler in the fluororesin gasket is preferably 3% by mass or more, more preferably 5% by mass or more, and still more preferably 10% by mass or more. From the viewpoint of improving the stress relaxation of the fluororesin gasket, the content is preferably 80% by mass or less, more preferably 75% by mass or less, and further preferably 70% by mass or less.

  As long as the object of the present invention is not hindered, for example, a fluorinated resin gasket may include a tackifier such as a terpene resin, a terpene-phenol resin, a coumarone resin, a coumarone-indene resin, a rosin, an ultraviolet absorber, and an antioxidant. Agents and coloring agents such as pigments may be contained in appropriate amounts.

  The resin composition for forming a gasket used as a raw material of a gasket made of a fluororesin is made of a fluororesin, a filler, and, if necessary, a processing aid, an additive, etc., in any order at once, or by dividing a small amount into a plurality of times. It can be prepared by mixing so as to have an appropriate composition. In addition, in order to obtain a gasket-forming resin composition having a uniform composition, an excessive amount of a processing aid is added to the gasket-forming resin composition, and after sufficient stirring, an excess processing aid is, for example, You may remove by means, such as filtration and volatilization.

  The fluororesin gasket can be manufactured, for example, by molding a resin composition for forming a gasket into a sheet having a predetermined shape by extrusion molding or the like. The obtained fluororesin gasket can be volatilized and removed, if necessary, by leaving it at room temperature or by heating it appropriately, if necessary.

  The fluororesin gasket can be fired by heating at a temperature equal to or higher than the melting point of the fluororesin. The heating temperature of the fluororesin gasket is different depending on the type of the fluororesin and cannot be unconditionally determined.However, from the viewpoint of uniformly firing the entire fluororesin gasket and avoiding the decomposition of the fluororesin, usually, The temperature is preferably about 340 to 370 ° C.

  The fluororesin gasket obtained as described above may be used as it is or after being cut into a desired shape.

  The thickness of the fluororesin gasket is preferably 0.5 to 5 mm, and more preferably 1 to 3 mm, from the viewpoint of obtaining a wrapping gasket with small stress relaxation and excellent sealing properties.

  In the fluororesin wrapped gasket of the present invention, a fluororesin gasket is used as an annular core, and a fluororesin outer skin is used as an outer cover for covering the upper surface, inner peripheral surface, and lower surface of the fluororesin gasket. ing.

  Examples of the fluororesin used for the fluororesin sheath include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkylvinylether copolymer (PFA), and tetrafluoroethylene-hexafluoropropylene copolymer (FEP). ), Tetrafluoroethylene-ethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), and chlorotrifluoroethylene-ethylene copolymer (ECTFE). Is not limited only to such an example. These fluororesins may be used alone or in combination of two or more. Among these fluororesins, polytetrafluoroethylene (PTFE) is preferable from the viewpoint of moldability and workability.

  In addition, a filler may be contained in the fluororesin outer shell from the viewpoint of obtaining a wrapped gasket that has small stress relaxation and excellent sealing properties.

  Examples of the filler include those similar to the inorganic filler and the organic filler used in the fluororesin gasket. The inorganic filler and the organic filler may be used alone or in combination.

  From the viewpoint of improving the mechanical strength of the fluororesin skin, the content of the filler in the fluororesin skin is preferably 5% by mass or more, more preferably 10% by mass or more, and still more preferably 15% by mass or more. From the viewpoint of improving the stress relaxation of the fluororesin skin, the content is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less.

  As with the fluororesin gasket, within the range in which the object of the present invention is not impaired, for example, a terpene resin, a terpene-phenol resin, a coumarone resin, a coumarone-indene resin, and a tackiness imparting such as rosin are applied to the fluororesin skin. Agents, ultraviolet absorbers, antioxidants, coloring agents such as pigments and the like may be contained in appropriate amounts.

  The thickness of the fluororesin outer shell is preferably 50 to 600 μm, more preferably 50 to 600 μm, from the viewpoint of integrating the fluororesin gasket and the fluororesin outer shell, reducing stress relaxation, and obtaining a wrapped gasket excellent in sealability. Is 100 to 400 μm.

  The fluororesin sheath can be manufactured, for example, by cutting a fluororesin sleeve having a predetermined size with a lathe or the like. More specifically, the fluororesin sheath is cut, for example, by applying a cutting tool to a predetermined position on the outer peripheral surface of a cylindrical fluororesin sleeve having a predetermined thickness, and corresponding to the shape of the fluororesin gasket. It can be obtained by forming a groove. The fluororesin outer skin obtained by the above operation has a shape that covers the upper surface, the inner peripheral surface, and the lower surface of the fluororesin gasket.

  In the present invention, a fluororesin sheet can be used as the fluororesin skin. When a fluororesin sheet is used as the fluororesin outer skin, the upper surface, inner peripheral surface, and lower surface of the fluororesin gasket are covered with a ring-shaped fluororesin sheet to have a cross-sectional shape shown in FIG. A wrapped gasket made of fluororesin can be obtained.

  The fluororesin wrapped gasket of the present invention is, for example, using a fluororesin envelope having a groove corresponding to the shape of the fluororesin gasket, and after attaching the fluororesin gasket to the groove of the fluororesin envelope, the fluororesin It can be manufactured by thermocompression bonding of a gasket made of gasket and a sheath made of fluororesin. The degree of thermocompression bonding between the fluororesin gasket and the fluororesin sheath is preferably such that the fluororesin gasket and the fluororesin sheath are firmly integrated.

  The thermocompression bonding between the fluororesin gasket and the fluororesin shell is performed, for example, by sandwiching a fluororesin gasket in a groove of the fluororesin shell between two heating plates, and heating the heating plate. This can be done by pressing.

The heating temperature at the time of thermocompression bonding between the fluororesin gasket and the fluororesin outer cover cannot be determined unconditionally because it differs depending on the type of the fluororesin used for the fluororesin gasket and the fluororesin outer cover. From the viewpoint of firmly integrating the fluororesin gasket and the fluororesin outer skin and suppressing the thermal degradation of the fluororesin, the melting point of the fluororesin is preferably in the range of the decomposition temperature of the fluororesin, It is more preferable that the temperature is in the range of 10 ° C. higher than the melting point of the fluororesin to 10 ° C. lower than the decomposition temperature of the fluororesin, and 15 ° C. higher than the melting point of the fluororesin to decomposition of the fluororesin. More preferably, the temperature is within a range of 15 ° C. lower than the temperature. For example, when polytetrafluoroethylene is used as the fluororesin, the heating temperature at the time of thermocompression bonding between the fluororesin gasket and the fluororesin sheath is from 327 ° C. (melting point of polytetrafluoroethylene) to 370 ° C. (polytetrafluoroethylene ). ( The decomposition temperature of ethylene ), preferably 337 to 370 ° C, and more preferably 350 to 370 ° C.

  The pressure at the time of thermocompression bonding between the fluororesin gasket and the fluororesin outer skin differs depending on the heating temperature, heating time, etc. when thermocompression bonding the fluororesin gasket and the fluororesin outer skin, so it should be decided unconditionally. Therefore, it is preferable that the fluorocarbon resin gasket and the fluorocarbon resin sheath are firmly integrated with each other, and that the gasket and the fluorocarbon resin skin be appropriately adjusted within a range that does not cause deformation or deterioration. Normally, the pressure during thermocompression bonding between a fluororesin gasket and a fluororesin sheath is strongly integrated with the fluororesin gasket and the fluororesin sheath, and deformed into a fluororesin gasket and a fluororesin sheath. From the viewpoint of preventing deterioration or deterioration, the pressure is preferably 0.03 to 0.2 MPa, and more preferably 0.08 to 0.12 MPa.

  When the fluororesin gasket and the fluororesin outer skin are thermocompression bonded, the area where the fluororesin outer skin is thermocompression bonded on the upper and lower surfaces of the fluororesin gasket is the same as the fluororesin gasket and the fluororesin outer skin, respectively. From the viewpoint of firm integration, it is preferable that the fluororesin outer skin be 10 to 100% of the area of the portion in contact with the upper and lower surfaces of the fluororesin gasket.

  When performing thermocompression bonding between the fluororesin gasket and the fluororesin outer skin in several places, the locations where the fluororesin gaskets and the fluororesin outer skin are thermocompression bonded may be unevenly distributed, not at equal intervals. . However, from the viewpoint of uniformly integrating the fluororesin gasket and the fluororesin sheath, the fluororesin gasket and the fluororesin gasket and the fluororesin sheath are equally spaced at four to eight locations at the peripheral end of the fluororesin sheath. It is preferable that the resin outer skin is thermocompression-bonded.

  By thermocompression bonding the fluororesin gasket and the fluororesin outer skin as described above, a fluororesin envelope gasket in which the fluororesin gasket and the fluororesin outer skin are integrated can be obtained.

  Hereinafter, a schematic cross-sectional view of one embodiment of the fluororesin wrapped gasket of the present invention is shown in FIG. 1, but the present invention is not limited to only this embodiment.

  In the fluororesin wrapped gasket shown in FIG. 1, a fluororesin gasket 1 made of a fluororesin containing a filler is used as a core. A fluororesin outer skin 2 is formed around the fluororesin gasket 1 so as to cover the upper surface, the inner peripheral surface, and the lower surface of the fluororesin gasket 1. The fluororesin gasket 1 and the fluororesin skin 2 are integrated by thermocompression bonding at the contact surface between them.

  In the fluorine resin wrapped gasket shown in FIG. 1, the annular groove 3 is formed. The annular groove 3 does not necessarily have to be formed. The annular groove 3 may be filled with an adhesive (not shown) for adhering the fluororesin gasket 1 and the fluororesin sheath 2 as necessary, and a filler (not shown) May be filled. Further, in order to discharge gas, liquid, and the like in the annular groove 3 to the outside of the fluororesin wrapped gasket, the annular groove 3 is connected to the outside of the fluororesin wrapped gasket by a through hole communicating in a radial direction. You may.

  In the fluororesin wrapped gasket shown in FIG. 1, the annular groove 3 is formed. For example, when the fluororesin wrapped gasket is tightened between flanges and used by venting high-pressure gas into the pipe, The high-pressure gas may permeate the fluororesin sheath 2 and increase the internal pressure of the annular groove 3. At this time, when the flange is opened, the gas in the annular groove 3 may blow out to the outside through the boundary surface between the fluororesin gasket 1 and the fluororesin sheath 2.

  On the other hand, when the fluororesin gasket and the fluororesin outer cover are firmly thermocompressed, and the thermocompression bonding strength between the fluororesin gasket and the fluororesin outer cover is adjusted to be 0.5 N / mm or more. Thus, it is possible to suppress the gas in the annular groove 3 of the fluororesin wrapping gasket from flowing out to the outside through the boundary surface between the fluororesin gasket 1 and the fluororesin outer skin 2. The thermocompression bonding strength between the fluororesin gasket and the fluororesin sheath is a value measured according to the method described in the following examples. When the annular groove 3 is filled with an adhesive, a filler or the like in advance, it is possible to prevent the high-pressure gas from being impregnated into the annular groove 3. Gas can be prevented from blowing out of the fluororesin wrapping gasket.

  Further, in order to discharge gas, liquid, and the like in the annular groove 3 to the outside of the fluororesin wrapped gasket, the annular groove 3 is connected to the outside of the fluororesin wrapped gasket by a through hole communicating in a radial direction. You may. When the through-hole is formed in this way, gas, liquid, and the like existing in the annular groove 3 can be discharged to the outside of the fluororesin-enclosed gasket as needed through the through-hole.

  Further, in order to discharge gas, liquid, and the like in the annular groove 3 to the outside of the wrapped gasket made of fluororesin, for example, a gasket 1 made of fluororesin is formed by stacking a plurality of gaskets of about 2 to 4 sheets. You may. When the gasket 1 made of fluororesin is formed by stacking a plurality of gaskets as described above, the gas or liquid in the annular groove 3 is wrapped with the fluorocarbon resin at any time via the contact surface of the gasket overlapped. It can be discharged outside the gasket. In this case, the contact surface of the gaskets to be superimposed may be provided with grooves, irregularities, etc. for efficiently discharging the gas or liquid in the annular groove 3 to the outside of the wrapping gasket made of fluororesin.

  FIG. 2 is a schematic sectional view showing another embodiment of the wrapping gasket made of fluororesin of the present invention. The fluororesin wrapped gasket shown in FIG. 2 uses a fluororesin gasket 1 made of a fluororesin containing a filler as a core, similarly to the fluororesin wrapped gasket shown in FIG. A fluororesin outer skin 2 is formed so as to cover the upper surface, the inner peripheral surface, and the lower surface of the resin gasket 1. The fluororesin gasket 1 and the fluororesin skin 2 are integrated by thermocompression bonding at the contact surface between them.

  The cross-sectional shape of the annular groove 3 formed by the fluororesin wrapped gasket shown in FIG. 1 is triangular, whereas the cross-sectional shape of the annular groove 3 formed by the fluororesin wrapped gasket shown in FIG. Are different in that they are square, but the fluororesin wrapped gasket shown in FIG. 2 may be otherwise the same as the fluororesin wrapped gasket shown in FIG. The cross-sectional shape of the annular groove 3 formed in the fluororesin wrapped gasket may be a semicircle other than the triangle illustrated in FIG. 1 and the square illustrated in FIG. 2. It is not limited by the cross-sectional shape of the groove 3.

  Since the fluororesin wrapped gasket of the present invention configured as described above uses a fluororesin gasket made of a fluororesin containing a filler as a core, it is excellent in durability and stress relaxation. It has the advantage of being small. In addition, since the resin component of the fluororesin gasket is a fluororesin, the fluororesin gasket is unlikely to deteriorate, and therefore, it is necessary to prevent the contents in the piping from leaking due to the deterioration of the fluororesin gasket. Can be.

  In addition, since the fluororesin wrapped gasket of the present invention is such that the fluororesin gasket and the fluororesin outer shell are both formed of substantially the same fluororesin, the fluororesin gasket and the fluororesin outer cover are Since it is firmly integrated by thermocompression bonding, it is possible to prevent the fluororesin sheath from peeling off from the fluororesin gasket.

  Furthermore, since the fluororesin wrapped gasket of the present invention has the fluororesin gasket and the fluororesin outer skin integrated by thermocompression bonding, it is possible to prevent the fluororesin gasket and the fluororesin outer skin from slipping. Can be. In addition, the fluororesin wrapped gasket of the present invention has excellent sealing properties with respect to piping and the like, in comparison with a fluororesin wrapped gasket in which the fluororesin gasket and the fluororesin outer cover are not thermocompression-bonded, This has the advantage that crushing of the resin skin is unlikely to occur.

  Therefore, the fluororesin wrapping gasket of the present invention does not require the use of a porous fluororesin as in the related art, and has a small stress relaxation. Therefore, for example, the gasket is suitably used as a pipe sealing material at a connection between pipes. Can be used.

  Next, the present invention will be described in more detail based on examples, but the present invention is not limited to only these examples.

Example 1
Clay powder (manufactured by Showa KDE Co., Ltd., product number: NK-300, average particle size: 10 μm) was used as a filler, and the clay powder was mixed with polytetrafluoroethylene so that the content of the clay powder in the gasket was 60% by mass. A mixture of fluoroethylene (PTFE) fine powder (manufactured by Daikin Industries, Ltd., product number: F104) and a mixture of 1350 g of the obtained mixture and a hydrocarbon-based organic solvent [manufactured by ExxonMobil Co., Ltd., trade name: Isopar G] 250 g Was mixed in a kneader for 5 minutes, and extruded with an extruder having a die opening size of 300 mm × 20 mm to produce a preform.

  Next, a biaxial roll (roll diameter: 700 mm, roll interval: 20 mm) and a biaxial roll (roll diameter: 700 mm, roll diameter adjusted to a roll speed of 6 m / min and a roll temperature of 40 ° C.) The preform obtained above is sequentially passed through a biaxial roll (roll diameter: 700 mm, roll interval: 5 mm) and a biaxial roll (roll diameter: 700 mm, roll interval: 3 mm), a biaxial roll (roll: 700 mm, roll interval: 5 mm). By doing so, a sheet having a thickness of 3 mm was produced.

  After leaving the sheet obtained above in an atmosphere at room temperature (about 25 ° C.) for 24 hours to remove the solvent contained in the sheet, the sheet is placed in an electric furnace and placed at 350 ° C. for 3 hours. By firing, a fluororesin gasket having a gasket size of JIS 10K 100A was obtained.

  A fluororesin (polytetrafluoroethylene) outer skin having a cross-sectional shape shown in FIG. 1 and a thickness of 0.4 mm is mounted on the fluororesin gasket obtained above, and the fluorine is provided with the outer skin. By sandwiching a resin gasket between two flat metal plates heated to 350 ° C., heating at a pressure of 0.1 MPa for 10 minutes, and fusing a fluororesin skin over the entire surface of the fluororesin gasket, A wrapped gasket made of fluororesin was prepared.

  Next, a heat cycle test was performed on the fluororesin wrapped gasket obtained above under the following conditions. Since the sealable internal pressure was 2.5 MPa or more, the fluororesin wrapped gasket obtained above was obtained. It was confirmed that the wrapped gasket had excellent sealing properties.

[Heat cycle test]
A test piece was prepared by mounting a fluororesin wrapped gasket between two carbon steel (S25C) flanges and tightening with a bolt made of alloy steel (SNB7) so that the gasket tightening surface pressure was 25 MPa. The specimen obtained above was heated from room temperature, kept at a temperature of 200 ° C. for 48 hours, and subjected to three cycles of a heat cycle test in which a series of operations of cooling to room temperature was performed as one cycle. The measurement was performed by increasing the sealable surface pressure required for the amount of air leaking from between the resin-wrapped gasket and the flange to be 1.7 × 10 ⁻⁴ Pa · m ³ / s in increments of 0.5 MPa.

Example 2
A wrapped gasket made of fluororesin was produced in the same manner as in Example 1, except that the content of the clay powder in the gasket made of fluororesin was adjusted to be 10% by mass.

  Next, a heat cycle test of the wrapped gasket made of the fluororesin obtained above was performed in the same manner as in Example 1. Since the sealable internal pressure was 2.5 MPa or more, the fluorinated resin obtained above was obtained. It was confirmed that the wrapped gasket had excellent sealing properties.

Example 3
A wrapping gasket made of fluororesin was produced in the same manner as in Example 1, except that the content of the clay powder in the gasket made of fluororesin was adjusted to be 20% by mass.

  Next, a heat cycle test of the wrapped gasket made of the fluororesin obtained above was performed in the same manner as in Example 1. Since the sealable internal pressure was 2.5 MPa or more, the fluorinated resin obtained above was obtained. It was confirmed that the wrapped gasket had excellent sealing properties.

Example 4
A wrapped gasket made of fluororesin was produced in the same manner as in Example 1, except that the content of the clay powder in the fluorinated resin gasket was adjusted to be 40% by mass.

  Next, a heat cycle test of the wrapped gasket made of the fluororesin obtained above was performed in the same manner as in Example 1. Since the sealable internal pressure was 2.5 MPa or more, the fluorinated resin obtained above was obtained. It was confirmed that the wrapped gasket had excellent sealing properties.

Example 5
In Example 1, a wrapped gasket made of fluororesin was produced in the same manner as in Example 1, except that the content of the clay powder in the gasket made of fluororesin was adjusted to be 50% by mass.

  Next, a heat cycle test of the wrapped gasket made of the fluororesin obtained above was performed in the same manner as in Example 1. Since the sealable internal pressure was 2.5 MPa or more, the fluorinated resin obtained above was obtained. It was confirmed that the wrapped gasket had excellent sealing properties.

Example 6
Example 1 was the same as Example 1 except that glass particles (average particle diameter: 30 μm) were used as the filler and the content of the filler (glass particles) in the fluororesin gasket was adjusted to 20% by mass. In the same manner as in Example 1, a wrapping gasket made of fluororesin was produced.

  Next, a heat cycle test of the wrapped gasket made of the fluororesin obtained above was performed in the same manner as in Example 1. Since the sealable internal pressure was 2.5 MPa or more, the fluorinated resin obtained above was obtained. It was confirmed that the wrapped gasket had excellent sealing properties.

Example 7
Example 1 was the same as Example 1 except that glass particles (average particle diameter: 100 μm) were used as the filler and the content of the filler (glass particles) in the fluororesin gasket was adjusted to 20% by mass. In the same manner as in Example 1, a wrapping gasket made of fluororesin was produced.

  Next, a heat cycle test of the wrapped gasket made of the fluororesin obtained above was performed in the same manner as in Example 1. Since the sealable internal pressure was 2.5 MPa or more, the fluorinated resin obtained above was obtained. It was confirmed that the wrapped gasket had excellent sealing properties.

Example 8
In Example 1, except that silicon carbide particles (average particle diameter: 50 μm) were used instead of glass particles as the filler, and the content of the filler (silicon carbide particles) in the fluororesin gasket was adjusted to 10% by mass. In the same manner as in Example 1, a wrapping gasket made of fluororesin was produced.

  Next, a heat cycle test of the wrapped gasket made of the fluororesin obtained above was performed in the same manner as in Example 1. Since the sealable internal pressure was 2.5 MPa or more, the fluorinated resin obtained above was obtained. It was confirmed that the wrapped gasket had excellent sealing properties.

Example 9
In Example 1, except that alumina particles (average particle size: 50 μm) were used instead of glass particles as the filler, and the content of the filler (alumina particles) in the fluororesin gasket was adjusted to 10% by mass. In the same manner as in Example 1, a wrapped gasket made of fluororesin was produced.

  Next, a heat cycle test of the wrapped gasket made of the fluororesin obtained above was performed in the same manner as in Example 1. Since the sealable internal pressure was 2.5 MPa or more, the fluorinated resin obtained above was obtained. It was confirmed that the wrapped gasket had excellent sealing properties.

Example 10
In Example 1, except that silica particles (average particle diameter: 50 μm) were used instead of glass particles as the filler and the content of the filler (silica particles) in the fluororesin gasket was adjusted to 10% by mass. In the same manner as in Example 1, a wrapped gasket made of fluororesin was produced.

  Next, a heat cycle test of the wrapped gasket made of the fluororesin obtained above was performed in the same manner as in Example 1. Since the sealable internal pressure was 2.5 MPa or more, the fluorinated resin obtained above was obtained. It was confirmed that the wrapped gasket had excellent sealing properties.

Example 11
In Example 1, a fluororesin wrapped gasket was prepared in the same manner as in Example 1 except that the fluororesin outer skin was fused to 10% of the area of the fluororesin gasket (fusion rate: 10%). did.

  Next, a heat cycle test of the wrapped gasket made of the fluororesin obtained above was performed in the same manner as in Example 1. Since the sealable internal pressure was 2.5 MPa or more, the fluorinated resin obtained above was obtained. It was confirmed that the wrapped gasket had excellent sealing properties.

Example 12
A wrapped gasket made of fluororesin was produced in the same manner as in Example 1, except that the outer surface made of fluororesin was fused to 5% of the area of the fluororesin gasket (fusion rate: 5%). did.

  Next, when a heat cycle test of the wrapped gasket made of the fluororesin obtained above was performed in the same manner as in Example 1, the sealable internal pressure was 1.5 MPa. It was confirmed that the wrapped gasket had excellent sealing properties.

Example 13
In Example 1, as a fluororesin skin, a fluororesin skin having a cross-sectional shape shown in FIG. 1 and a thickness of 0.4 mm [content of glass fiber (fiber length: 5 μm): 20% by mass] A fluororesin wrapped gasket was produced in the same manner as in Example 1 except that the gasket was used.

  Next, a heat cycle test of the wrapped gasket made of the fluororesin obtained above was performed in the same manner as in Example 1. Since the sealable internal pressure was 2.5 MPa or more, the fluorinated resin obtained above was obtained. It was confirmed that the wrapped gasket had excellent sealing properties.

Example 14
In Example 1, as a fluororesin skin, a fluororesin skin having a cross-sectional shape shown in FIG. 1 and a thickness of 0.4 mm [content of carbon fiber (fiber length: 5 μm): 30% by mass] A fluororesin wrapped gasket was produced in the same manner as in Example 1 except that the gasket was used.

  Next, the heat cycle test of the wrapped gasket made of the fluororesin obtained above was performed in the same manner as in Example 1. Since the sealable internal pressure was 2.5 MPa or more, the fluorinated resin obtained above was obtained. It was confirmed that the wrapped gasket had excellent sealing properties.

Example 15
In Example 1, as the fluororesin skin, a fluororesin skin having a cross-sectional shape shown in FIG. 1 and a thickness of 0.4 mm [glass fiber (fiber length: 5 μm) and carbon fiber (fiber length: 5 μm) )), A fluororesin wrapped gasket was produced in the same manner as in Example 1 except that the content of the mixed fiber with ()) was used.

  Next, the heat cycle test of the wrapped gasket made of the fluororesin obtained above was performed in the same manner as in Example 1. Since the sealable internal pressure was 2.5 MPa or more, the fluorinated resin obtained above was obtained. It was confirmed that the wrapped gasket had excellent sealing properties.

Example 16
In Example 1, as a fluororesin skin, a fluororesin skin having a cross-sectional shape shown in FIG. 1 and a thickness of 0.4 mm [content of copper-tin alloy particles (average particle diameter: 10 μm): 30% by mass)], except that a wrapping gasket made of fluororesin was produced in the same manner as in Example 1.

  Next, the heat cycle test of the wrapped gasket made of the fluororesin obtained above was performed in the same manner as in Example 1. Since the sealable internal pressure was 2.5 MPa or more, the fluorinated resin obtained above was obtained. It was confirmed that the wrapped gasket had excellent sealing properties.

Example 17
In Example 1, as a fluororesin skin, a fluororesin skin having a cross-sectional shape shown in FIG. 1 and a thickness of 0.4 mm [content of carbon fiber (fiber length: 5 μm): 10% by mass] A fluororesin wrapped gasket was produced in the same manner as in Example 1 except that the gasket was used.

  Next, the heat cycle test of the wrapped gasket made of the fluororesin obtained above was performed in the same manner as in Example 1. Since the sealable internal pressure was 2.5 MPa or more, the fluorinated resin obtained above was obtained. It was confirmed that the wrapped gasket had excellent sealing properties.

Comparative Example 1
In Example 1, a wrapped gasket made of fluororesin was produced in the same manner as in Example 1, except that no filler was used in the gasket made of fluororesin.

  Next, a heat cycle test of the fluororesin wrapped gasket obtained above was performed in the same manner as in Example 1. Since the sealable internal pressure was 1 MPa, the fluororesin wrapped gasket obtained above was obtained. Was inferior in sealability.

  From the above results, the fluororesin wrapped gasket obtained in each of the examples uses a fluororesin gasket containing a filler, so that the stress relaxation is small, so that excellent sealing properties are maintained. You can see that.

Example 18
Clay powder (manufactured by Showa KDE Co., Ltd., product number: NK-300, average particle size: 10 μm) was used as a filler, and the clay powder was mixed with polytetrafluoroethylene so that the content of the clay powder in the gasket was 60% by mass. A mixture of fluoroethylene (PTFE) fine powder (manufactured by Daikin Industries, Ltd., product number: F104) and a mixture of 1350 g of the obtained mixture and a hydrocarbon-based organic solvent [manufactured by ExxonMobil Co., Ltd., trade name: Isopar G] 250 g Was mixed in a kneader for 5 minutes, and extruded with an extruder having a die opening size of 300 mm × 20 mm to produce a preform.

  Next, a biaxial roll (roll diameter: 700 mm, roll interval: 20 mm) and a biaxial roll (roll diameter: 700 mm, roll diameter adjusted to a roll speed of 6 m / min and a roll temperature of 40 ° C.) The preform obtained above is sequentially passed through a biaxial roll (roll diameter: 700 mm, roll interval: 5 mm) and a biaxial roll (roll diameter: 700 mm, roll interval: 3 mm), a biaxial roll (roll: 700 mm, roll interval: 5 mm). By doing so, a sheet having a thickness of 2 mm was produced.

  After leaving the sheet obtained above in an atmosphere at room temperature (about 25 ° C.) for 24 hours to remove the solvent contained in the sheet, the sheet is put in an electric furnace and placed at 350 ° C. for 3 hours. By calcining, a fluororesin gasket having a gasket size of JIS 10K 25A was obtained.

  The fluororesin gasket having the cross-sectional shape shown in FIG. 1 and having a thickness of 0.2 mm is attached to the fluororesin gasket obtained above, and the fluororesin gasket to which the outer skin is attached is brought to 350 ° C. By sandwiching and heating between two heated flat metal plates, a fluororesin outer shell is fused to the entire surface of the fluororesin gasket to produce a fluororesin wrapped gasket having the thermocompression strength shown in Table 1. did. The thermocompression bonding strength was measured based on the following method.

[Measurement method of thermocompression bonding strength]
For the measurement of the thermocompression bonding strength, a precision universal testing machine [manufactured by Shimadzu Corporation, trade name: Autograph AG-50KNX type] was used.

  Peel off a part (length: about 10 mm) of the fluororesin outer skin of the fluororesin wrapped gasket, hold the peeled fluororesin outer skin on the upper chuck of a precision universal testing machine, and then chuck the gasket with the peeled surface , A tensile test is performed at a tensile speed of 30 mm / min, a maximum load (N) at a moving distance between the chucks of 10 to 20 mm is obtained, and the maximum load (N) is peeled off from the fluororesin outer skin. By dividing by the distance (mm), the thermocompression bonding strength (N / mm) was obtained.

  Next, the presence or absence of gas leakage from the annular groove of the fluororesin wrapped gasket obtained above was evaluated based on the following method. Table 1 shows the results.

[Evaluation of gas leakage]
A gasket made of wrapped fluororesin was mounted on a test platen (standard: JIS B2490), a compressive load was applied so that the surface pressure became 20 MPa, and helium gas was applied so that the internal pressure became 2.0 MPa. After standing for a period of time, the internal pressure and the compressive load were removed. Take out the gasket from the test platen, visually observe whether there is peeling from the annular groove to the outside between the fluoroplastic outer shell and the gasket of the fluoroplastic wrapped gasket, and evaluate based on the following evaluation criteria did.

In addition, when peeling from the annular groove to the outside was recognized between the gasket and the fluororesin sheath of the fluororesin wrapped gasket, it was evaluated that there was gas leakage.
(Evaluation criteria)
：: No peeling was observed.
X: The peeling was observed.

Example 19
In Example 18, except that the gasket size of the fluororesin gasket was changed from JIS 10K 25A to JIS 10K 50A, a fluororesin wrapped gasket was prepared in the same manner as in Example 18, and the thermocompression bonding strength was examined. The presence or absence of leakage was evaluated. Table 2 shows the results.

Example 20
In Example 18, except that the gasket size of the fluororesin gasket was changed from JIS 10K 25A to JIS 10K 100A, a fluororesin wrapped gasket was produced in the same manner as in Example 18, and the thermocompression bonding strength was examined. The presence or absence of leakage was evaluated. Table 3 shows the results.

Example 21
In Example 18, except that the gasket size of the fluororesin gasket was changed from JIS 10K 25A to JIS 10K 150A, a fluororesin wrapped gasket was produced in the same manner as in Example 18, and the thermocompression bonding strength was examined. The presence or absence of leakage was evaluated. Table 4 shows the results.

Example 22
In Example 18, except that the gasket size of the fluororesin gasket was changed from JIS 10K 25A to JIS 10K 175A, a fluororesin wrapped gasket was produced in the same manner as in Example 18, and the thermocompression bonding strength was examined. The presence or absence of leakage was evaluated. Table 5 shows the results.

Example 23
In Example 18, except that the gasket size of the fluororesin gasket was changed from JIS 10K 25A to JIS 10K 200A, a fluororesin wrapped gasket was prepared in the same manner as in Example 18, and the thermocompression bonding strength was examined. The presence or absence of leakage was evaluated. Table 6 shows the results.

From the results of Examples 18 to 23, has a cross-sectional shape shown in FIG. 1, in the case of using the fluororesin covered gasket that an annular groove is formed, thermal pressure Chakukyodo the fluororesin outer skin and the gasket Is adjusted to be 0.5 N / mm or more, it can be understood that leakage of gas from the annular groove of the wrapping gasket made of fluororesin can be suppressed.

DESCRIPTION OF SYMBOLS 1 Fluororesin gasket 2 Fluororesin skin 3 Annular groove

Claims (4)

A wrapping gasket having an annular core and an outer cover covering an upper surface, an inner peripheral surface, and a lower surface of the core, wherein the core is a fluororesin gasket made of a fluororesin containing a filler. wood has an average particle size of the particulate filler is 1 to 100 [mu] m, the content of the particulate filler in the fluororesin gasket is 3 to 80 mass%, the particulate filler Carbon-based particles, clay, silica particles, alumina particles, silicon carbide particles, inorganic particles selected from the group consisting of glass particles and metal particles, wherein the outer skin is a non-porous fluororesin outer skin, A gasket and the outer cover are fused and integrated, and a thermocompression bonding strength between the fluororesin gasket and the outer cover is 0.5 N / mm or more, Socket.   The wrapping gasket made of fluororesin according to claim 1, wherein the outer skin contains a filler. A method of manufacturing a wrapped gasket having a skin covering the top surface and the inner peripheral surface a lower surface of the core and the center-core in the annular particulate filler having an average particle diameter of 1~100μm as the wick The particulate filler is inorganic particles selected from the group consisting of carbon-based particles, clay, silica particles, alumina particles, silicon carbide particles, glass particles, and metal particles. using Oh Ru fluororesin gasket, using a non-porous fluorine resin outer skin as the outer skin, covering the upper surface and the inner peripheral surface of the fluororesin gasket and the lower surface in the skin, and the fluororesin gasket and the outer skin For producing a fluororesin wrapped gasket, wherein the gasket and the outer skin are adjusted to have a thermocompression bonding strength of 0.5 N / mm or more.   The method according to claim 3, wherein the outer skin contains a filler.

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