JP2008273199A - Sealing material - Google Patents

Abstract

The present invention provides a sealing material that can secure a sufficient sealing property and is excellent in slidability and anti-sticking property.
A sealing material is formed by laminating a polytetrafluoroethylene porous film obtained by stretching an unfired body or a semi-fired body of polytetrafluoroethylene in a biaxial direction on a surface of a sealing material body formed of an elastomer. .
[Selection] Figure 1

Description

  The present invention relates to a sealing material in which a stretched porous film of polytetrafluoroethylene is laminated on the surface of a sealing material body.

  Conventionally, when a vacuum vessel or the like is configured by combining members, sealing is secured through a sealing material in consideration of maintenance and the like. For example, in a plasma etching apparatus, a reactive gas is introduced into a vacuum and turned into plasma by applying a high frequency. However, when a synthetic rubber sealing material generally used for a vacuum shield is used, a portion exposed to the plasma gradually deteriorates. Particles are generated, and finally cracks occur and the vacuum cannot be maintained. A general synthetic rubber sealing material is not only inferior in corrosion resistance in this way, but also inferior in heat resistance, and thus has a problem that the replacement frequency is increased.

  When a seal material made of a fluororesin having corrosion resistance is used instead of the synthetic rubber seal material, the elasticity is low and the outside air blocking property is low. For this reason, fluorine-containing perfluoro rubber has been developed, but it is expensive and has a problem that it costs 100 to 1000 times as much as a normal synthetic rubber-based sealing material. Therefore, Patent Document 1 proposes a composite material in which a fluororesin fiber layer is laminated on the surface of a rubber base body which is a sealing material body. Patent Document 2 proposes a laminate obtained by vulcanizing and bonding a perfluoro rubber layer and a fluororesin layer.

JP 7-227935 A JP 2000-313089 A

  An object of this invention is to provide the sealing material which can ensure sufficient sealing performance, and was excellent in slidability and sticking prevention property.

  The present invention relates to a sealing material in which a polytetrafluoroethylene porous film obtained by stretching an unfired or semi-fired polytetrafluoroethylene is laminated on the surface of a sealing material body formed of an elastomer.

  The polytetrafluoroethylene porous membrane is preferably a polytetrafluoroethylene porous membrane stretched in the biaxial direction.

  The elastomer is preferably a fluorine-containing elastomer.

  The porosity of the polytetrafluoroethylene porous membrane is preferably 40 to 99%.

  The thickness of the polytetrafluoroethylene porous membrane is preferably 5 to 150 μm.

  The present invention also relates to a method for producing the sealing material obtained by superposing and integrally molding an unvulcanized elastomer and a polytetrafluoroethylene porous membrane.

  In the present invention, since the surface of the sealing material body is laminated with a stretched polytetrafluoroethylene porous film, it has corrosion resistance and high sealing properties, and there is no fuzz on the surface of the sealing material, and surface smoothness and flexibility. In addition, it is possible to obtain a sealing material that is excellent in prevention of sticking to a member in contact with the sealing material.

  The present invention relates to a sealing material formed by laminating a porous film obtained by stretching an unfired body or a semi-fired body of polytetrafluoroethylene on the surface of a sealing material body formed of an elastomer.

  The sealing material body is formed from an elastomer and is not particularly limited as long as it is conventionally used for a sealing material. However, in view of heat resistance, vacuum sealing properties and plasma resistance, a fluorine-containing elastomer is used. Is preferably used. Examples of the fluorine-containing elastomer include fluororubber, thermoplastic fluororubber, and rubber compositions containing these fluororubbers.

  Examples of the fluoro rubber include non-perfluoro fluoro rubber and perfluoro fluoro rubber, and perfluoro fluoro rubber is particularly preferably used.

  Non-perfluorofluororubbers include vinylidene fluoride (VdF) fluororubber, tetrafluoroethylene (TFE) / propylene fluororubber, tetrafluoroethylene (TFE) / propylene / vinylidene fluoride (VdF) fluororubber, ethylene / Hexafluoroethylene (HFP) fluorine rubber, ethylene / hexafluoroethylene (HFP) / vinylidene fluoride (VdF) fluorine rubber, ethylene / hexafluoropropylene (HFP) / tetrafluoroethylene (TFE) fluorine rubber, fluoro Examples thereof include silicone-based fluororubber, fluorophosphazene-based fluororubber, and the like, which can be used alone or in any combination as long as the effects of the present invention are not impaired.

  Examples of the perfluorofluororubber include TFE / perfluoro (alkyl vinyl ether) (PAVE) / a fluorine-containing elastomer composed of a monomer that provides a crosslinking site. The composition of TFE / PAVE is preferably 50 to 90/10 to 50 (mol%), more preferably 50 to 80/20 to 50 (mol%), and still more preferably 55 to 70/30 to 45 (mol%). The monomer that gives a crosslinking site is preferably 0 to 5 mol%, more preferably 0 to 2 mol%, based on the total amount of TFE and PAVE. When the composition is out of the range, the properties as a rubber elastic body are lost, and the properties tend to be similar to those of a resin.

  Examples of PAVE in this case include perfluoro (methyl vinyl ether) and perfluoro (propyl vinyl ether), and these can be used alone or in any combination within a range not impairing the effects of the present invention. .

  The sealing material body of the present invention may contain a filler. Fillers include polyimide, polyamideimide, polyetherimide, and other imide fillers; engineering plastics such as polyarylate, polysulfone, polyethersulfone, polyphenylene sulfide, polyetheretherketone, and polyoxybenzoate. Organic pigment fillers such as isoindolinone, quinacridone, diketopyrrolopyrrole and anthraquinone; metal oxide fillers such as aluminum oxide, silicon oxide and yttrium oxide; metal carbides such as silicon carbide and aluminum carbide; nitriding Metal nitride fillers such as silicon and aluminum nitride; Carbon compound fillers such as diamond, fullerene and graphite; such as aluminum fluoride and carbon fluoride Machine filler, and the like. Among these, aluminum oxide, yttrium oxide, silicon oxide, polyimide, carbon fluoride, and diamond are preferable from the viewpoint of the shielding effect of various plasmas.

  In particular, in fields where high purity and non-contamination are not required, the seal ring body 1 contains usual additives contained in the elastomer as necessary, such as fillers, processing aids, plasticizers, and colorants. You may let them.

  The sealing material of the present invention is formed by laminating a porous film obtained by stretching an unfired body or a semi-fired body of polytetrafluoroethylene (hereinafter also referred to as PTFE) on the surface of the sealing material body. When simply laminating PTFE, thin film processing of PTFE is difficult and thin film processing is limited, and the flexibility of the sealing material is impaired. However, according to the configuration of the present invention, such a problem is solved. The In addition, characteristics such as surface smoothness, fluffing, flexibility and sealing properties, which are disadvantages of Patent Document 1, are improved. Further, it is not necessary to perform a surface treatment on the surface of the fluororesin in order to perform vulcanization adhesion as in the laminate of Patent Document 2, and since an adhesive layer is required, flexibility that is a drawback is improved.

  PTFE used for the porous membrane includes not only a homopolymer of tetrafluoroethylene but also a copolymer of tetrafluoroethylene and other monomers capable of copolymerization not exceeding 2% by weight.

  The PTFE porous membrane of the present invention may contain a filler. Examples of the filler include fillers that may be blended in the above-described sealing material, but metal oxide, polyimide, and diamond fine particle fillers are preferable from the viewpoint that properties such as wear resistance and plasma resistance can be imparted.

  The PTFE porous membrane is a process of obtaining a sheet-like extrudate by extruding a paste-like mixture of unfired or semi-fired PTFE fine powder as a raw material and an extrusion aid such as naphtha with an extruder and then rolling the mixture. The obtained rolled product is obtained by heating or extracting it with a solvent such as trichloroethane or trichlorethylene, and removing the extrusion aid and stretching the rolled product not containing the extrusion aid.

  In the step of removing the extrusion aid, when it is removed by heating, the heating temperature can be appropriately selected depending on the extrusion aid, but is preferably 200 to 300 ° C. It is particularly preferable to heat at around 250 ° C. If the temperature exceeds 300 ° C., especially 327 ° C., which is the melting point of PTFE, there is a tendency to be fired.

  Examples of the stretching direction in the stretching step include a biaxial direction. The biaxial stretching (biaxial stretching) may be sequential biaxial stretching or simultaneous biaxial stretching. Moreover, you may preheat at about 300 degreeC before extending | stretching. The draw ratio is preferably 20 to 500 magnification, more preferably 30 to 300 magnification, and even more preferably 50 to 200 magnification, from the viewpoint that the intended basis weight and porosity can be obtained. The draw ratio is obtained by multiplying the stretch ratio in the longitudinal direction and the stretch ratio in the transverse direction.

  The porosity of the PTFE porous membrane is preferably 40% or more, and more preferably 60% or more from the viewpoint of good adhesion to the mating base material at the time of compounding. Further, the porosity of the PTFE porous membrane is preferably 99% or less, and more preferably 97% or less, from the viewpoint that the handleability during processing is good.

  The thickness of the PTFE porous membrane is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 20 μm or more from the viewpoint that the porous membrane does not break and is excellent in moldability. Moreover, 150 micrometers or less are preferable from the point that the crack or leak of a porous film does not arise, 100 micrometers or less are more preferable, and 50 micrometers or less are further more preferable.

The weight per unit area of the porous PTFE membrane within the preferable ranges of the porosity and thickness is 200 g / m ² or less, and more preferably 50 g / m ² or less. Moreover, 0.5 g / m < ² > or more is preferable and 1.0 g / m < ² > or more is more preferable from the point that the porous film does not break and is excellent in moldability.

  The composition used for the main body of the sealing material of the present invention can be prepared by mixing each of the above-described components using an ordinary elastomer processing machine, for example, an open roll, a Banbury mixer, a kneader or the like. In addition, it can be prepared by a method using a closed mixer.

  A method for obtaining a preform from the composition may be a normal method, and may be performed by a known method such as a method of heat-compressing with a mold, a method of press-fitting into a heated mold, or a method of extruding with an extruder. it can.

  The sealing material of the present invention is a method in which a preformed PTFE porous membrane is placed in a mold of the sealing material, and is filled with an unvulcanized elastomer composition and pressed, and the PTFE porous membrane is formed on the surface of a preform. Can be manufactured by a method of forming a non-adhering material layer on the surface of the sealing material after the pressing.

  The sealing material of this invention can be used suitably in the field | area shown below.

  In semiconductor-related fields such as semiconductor manufacturing equipment, liquid crystal panel manufacturing equipment, plasma panel manufacturing equipment, plasma addressed liquid crystal panels, field emission display panels, solar cell substrates, O (square) rings, packing, sealing materials, gaskets, diaphragms, etc. These can be used for CVD apparatus, dry etching apparatus, wet etching apparatus, oxidation diffusion apparatus, sputtering apparatus, ashing apparatus, cleaning apparatus, ion implantation apparatus, and exhaust apparatus. Specifically, as a gate valve O-ring, seal material, quartz window O-ring, seal material, chamber O-ring, seal material, gate O-ring, seal material, bell jar O-ring, seal material As an O-ring for a coupling, as a sealing material, as an O-ring for a pump, as a sealing material, as a diaphragm, as an O-ring for a semiconductor gas control device, as a sealing material, as an O-ring for a resist developer, as a stripping solution, as a sealing material Can be used.

  In the automotive field, gaskets, shaft seals, valve stem seals, seal materials can be used for engines and peripheral devices, seal materials can be used for AT devices, O (square) rings, packings, seal materials and diaphragms It can be used for fuel systems as well as peripheral devices. Specifically, engine head gasket, metal gasket, oil pan gasket, crankshaft seal, camshaft seal, valve stem seal, manifold packing, oxygen sensor seal, injector O-ring, injector packing, fuel pump O-ring, diaphragm, Crankshaft seal, gearbox seal, power piston seal, cylinder liner seal, valve stem seal, automatic transmission front pump seal, rear axle pinion seal, universal joint gasket, speedometer pinion seal, foot brake piston Diaphragm for cup, torque transmission O-ring, oil seal, exhaust gas reburning device seal, bearing seal, carburetor sensor It can be used as a beam or the like.

  In the aircraft field, the rocket field, and the ship field, there are diaphragms, O (square) rings, valves, packings, sealing materials, and the like, which can be used for fuel systems. Specifically, in the aircraft field, it is used for jet engine valve steal seals, gaskets and O-rings, rotating shaft seals, hydraulic equipment gaskets, firewall seals, etc., and in the marine field, screw propeller shaft stern seals, Used for intake and exhaust valve stem seals of diesel engines, valve seals of butterfly valves, shaft seals of butterfly valves, and the like.

  In the field of chemical products such as plants, there are valves, packings, diaphragms, O (square) rings, sealing materials, and the like, which can be used in the manufacturing process of chemical products such as pharmaceuticals, agricultural chemicals, paints, and resins. Specifically, chemical pumps, rheometers, pipe seals, heat exchanger seals, glass cooler packing for sulfuric acid production equipment, pesticide sprayers, pesticide transfer pump seals, gas pipe seals, plating solutions Seals, packing for high-temperature vacuum dryers, roller seals for papermaking belts, fuel cell seals, wind tunnel joint seals, gas chromatography, packing for pH meter tube connections, analytical instruments, physics and chemistry instrument seals, diaphragms, valve parts Etc. can be used.

  In the field of photography such as a developing machine, the field of printing such as a printing machine, and the field of painting such as a painting facility, it can be used as a seal or valve part of a dry copying machine.

  In the field of food plant equipment, valves, packings, diaphragms, O (square) rings, sealing materials and the like can be mentioned and used in food production processes. Specifically, it can be used as a seal for a plate heat exchanger, a solenoid valve seal for a vending machine, or the like.

  In the field of nuclear plant equipment, packing, O-rings, sealing materials, diaphragms, valves and the like can be mentioned.

  In the general industrial field, packing, O-rings, sealing materials, diaphragms, valves and the like can be mentioned. Specifically, hydraulic, lubrication machinery seals, bearing seals, dry cleaning equipment windows, other seals, uranium hexafluoride concentrator seals, cyclotron seals (vacuum) valves, automatic packaging machine seals, air Used for diaphragms (pollution measuring devices) of sulfur dioxide and chlorine gas analysis pumps.

  In the electric field, specifically, it is used as an insulating oil cap for Shinkansen, a benching seal for a liquid seal transformer, and the like.

  In the fuel cell field, specifically, it is used as a sealing material between electrodes and separators, a seal for hydrogen / oxygen / product water piping, and the like.

  In the electronic component field, specifically, it is used as a heat radiating material, an electromagnetic shielding material, a hard disk drive gasket of a computer, and the like.

  There are no particular limitations on what can be used for on-site molding, and examples include an engine oil pan gasket, a magnetic recording device gasket, and a clean room filter unit sealing agent.

  Further, it is particularly preferably used as a sealing material for clean equipment such as a gasket for a magnetic recording device (hard disk drive), a sealing material for a device storage such as a semiconductor manufacturing device or a wafer.

  Furthermore, taking advantage of characteristics such as chemical resistance, low gas permeability, flame retardancy, etc., it is also particularly suitably used for fuel cell sealing materials such as packing used between fuel cell electrodes and surrounding piping. .

  EXAMPLES Next, the present invention will be specifically described with reference to examples, but the present invention is not limited only to these examples.

Production Examples 1 to 6 (Production of biaxially stretched membrane)
The endothermic peak on the crystal melting diagram when the number average molecular weight is 5.8 million and the differential scanning calorimeter (DSC) has a heating rate of 10 ° C./min is 345 ° C. and does not show a shoulder near 330 ° C. and contains a comonomer. First prepared PTFE fine powder. 25 parts by weight of hydrocarbon oil (“Isopar M” manufactured by ExxonMobil) as an extrusion aid is added to 100 parts by weight of the PTFE fine powder, and a round bar paste is extruded by an extruder having a cylinder inner diameter of 130 mm and an extrusion die of 16 mm. This was calendered at a speed of 28 m / min with a calender roll heated to 70 ° C. to obtain a tape. This tape was passed through a hot air drying oven at 250 ° C. to remove the extrusion aid, and a PTFE green tape having an average thickness of 200 μm and an average width of 180 mm was produced.

  This green tape was first stretched in the longitudinal direction at a stretching temperature of 300 ° C. and a stretching speed of 200% / sec. Using a biaxial stretching machine, and then stretched in the transverse direction at a stretching temperature of 200 ° C. and a stretching speed of 50% / sec. After stretching by B times, the film was fixed with a frame so that the film did not shrink, and then heat-fixed by placing it in an oven at 350 ° C. for 3 minutes. It shows in Table 1 about the obtained stretched film. In addition, about the draw ratio, it computed by AxB.

Production Example 7 (Preparation of fluororubber 1 (binary fluororubber))
Fluororubber (Daikin Kogyo Co., Ltd. Daiel G-751), Carbon Black (Cancarb Corp. Thermax N-990), Magnesium Oxide (Kyowa Chemical Industry Co., Ltd. MA-150), and Calcium Hydroxide (Omi Chemical Co., Ltd.) CALDIC # 2000) was mixed with an open roll at a weight ratio of 100/20/3/6 (parts by weight).

に示す乳化剤を１０ｇ、ｐＨ調整剤としてリン酸水素二ナトリウム・１２水塩０．０９ｇを仕込み、系内を窒素ガスで充分に置換し脱気したのち、６００ｒｐｍで撹拌しながら、５０℃に昇温し、テトラフルオロエチレン（ＴＦＥ）とパーフルオロ（メチルビニルエーテル）（ＰＭＶＥ）の混合ガス（ＴＦＥ／ＰＭＶＥ＝２５／７５モル比）を、内圧が０．７８ＭＰａ・Ｇになるように仕込んだ。ついで、過硫酸アンモニウム（ＡＰＳ）の５２７ｍｇ／ｍＬの濃度の水溶液１０ｍＬを窒素圧で圧入して反応を開始した。 Production Example 8 (Synthesis of fluororubber (nitrile group-containing elastomer))
In a 3 mL stainless steel autoclave with no ignition source, 1 L of pure water and the formula:

10 g of the emulsifier shown in the above and 0.09 g of disodium hydrogen phosphate · 12 hydrate as a pH adjuster were added, the system was thoroughly purged with nitrogen gas, degassed, and then raised to 50 ° C. while stirring at 600 rpm. The mixture was heated and charged with a mixed gas of tetrafluoroethylene (TFE) and perfluoro (methyl vinyl ether) (PMVE) (TFE / PMVE = 25/75 molar ratio) so that the internal pressure became 0.78 MPa · G. Next, 10 mL of an aqueous solution of ammonium persulfate (APS) having a concentration of 527 mg / mL was injected under nitrogen pressure to initiate the reaction.

When the internal pressure dropped to 0.69 MPa · G due to the progress of the polymerization, 3 g of CF ₂ = CFOCF ₂ CF (CF ₃ ) OCF ₂ CF ₂ CN (CNVE) was injected under nitrogen pressure. Next, 4.7 g of TFE and 5.3 g of PMVE were respectively injected under their own pressure so that the pressure became 0.78 MPa · G. Thereafter, TFE and PMVE are injected in the same manner as the reaction proceeds, and the pressure is increased and decreased repeatedly between 0.69 and 0.78 MPa · G, and the total amount of TFE and PMVE is 70 g, 130 g, 190 g, and 250 g. At that time, 3 g of CNVE was injected under nitrogen pressure.

  19 hours after the start of the polymerization reaction, when the total amount of TFE and PMVE reached 300 g, the autoclave was cooled to release unreacted monomers, and 1330 g of an aqueous dispersion having a solid content concentration of 21.2% by weight. Got.

  1196 g of this aqueous dispersion was diluted with 3588 g of water and slowly added to 2800 g of 3.5 wt% aqueous hydrochloric acid with stirring. After stirring for 5 minutes after the addition, the coagulated product was filtered off, and the obtained polymer was further poured into 2 kg of HCFC-141b, stirred for 5 minutes, and filtered again. Thereafter, washing with HCFC-141b and filtration were repeated four more times, followed by vacuum drying at 60 ° C. for 72 hours to obtain 240 g of a nitrile group-containing elastomer.

As a result of ¹⁹ F-NMR analysis, the monomer unit composition of this polymer was TFE / PMVE / CNVE = 56.6 / 42.3 / 1.1 mol%.

Production Example 9 (Preparation of fluoro rubber 2 (perflo rubber))
A nitrile group-containing fluorine-containing elastomer obtained in Fluororubber Production Example 8 and a crosslinking agent synthesized by the method described in Journal of Polymer Science, Polymer Chemistry, Vol. 20, pages 2381 to 2393 (1982) 2,2-bis [3-amino-4- (N-phenylamino) phenyl] hexafluoropropane and carbon black (Thermax N-990, manufactured by Cancarb) in a weight ratio of 100 / 0.8 / 20 (weight) Part).

Production Example 10 (Production of fluororesin 1)
After pre-molding polytetrafluoroethylene (polyflon PTFE M12 manufactured by Daikin Industries, Ltd.) at a pressure of 17 MPa at room temperature, it is heated at a heating rate of 30 ° C./hour, held at a temperature of 370 ° C. for 10 hours, and a cooling rate of 30 ° C. It fired on the conditions cooled at / hour, and obtained the block of diameter 100mm and height 30mm. The block was skived to obtain a sheet having a thickness of 0.5 mm.

Production Example 11 (Production of fluororesin 2)
The sheet of fluororesin 1 obtained in Production Example 10 is immersed in a commercially available processing agent (Tetra Etch, manufactured by Junko Co., Ltd.) for 5 seconds, then washed with methyl alcohol and then with water to obtain a sheet whose surface is etched. It was.

  Further, a commercially available vulcanized adhesive for fluororubber (Rohm and Haas Japan Co., Ltd. MEGUM 3290-1) was applied to the adhesive surface of the sheet with a brush and air-dried at room temperature.

Example 1
The 4-fold stretched film of Production Example 2 obtained by the production of the biaxially stretched film and the fluororubber 1 obtained in Production Example 7 were superposed, and primary vulcanized at 170 ° C. for 10 minutes, and further at 230 ° C. for 24 hours. Secondary vulcanization for a time was performed to obtain a vulcanized rubber sheet having a thickness of 25 mm × 50 mm × 2 mm.

Example 2
A vulcanized rubber sheet was obtained in the same manner as in Example 1 except that the 25-fold stretched film obtained in Production Example 3 was used instead of the 4-fold stretched film.

Example 3
A vulcanized rubber sheet was obtained in the same manner as in Example 1 except that the 100-fold stretched film obtained in Production Example 4 was used instead of the 4-fold stretched film.

Example 4
A vulcanized rubber sheet was obtained in the same manner as in Example 1 except that the 300-fold stretched film obtained in Production Example 5 was used instead of the 4-fold stretched film.

Example 5
A vulcanized rubber sheet was obtained in the same manner as in Example 1 except that the 500-fold stretched film obtained in Production Example 6 was used instead of the 4-fold stretched film.

Example 6
The 4-fold stretched film of Production Example 2 obtained by the production of the biaxially stretched film and the fluororubber 2 obtained in Production Example 9 were superposed, and primary vulcanized at 180 ° C. for 20 minutes, and further at 290 ° C. for 18 Secondary vulcanization for a time was performed to obtain a vulcanized rubber sheet having a thickness of 25 mm × 50 mm × 2 mm.

Example 7
A vulcanized rubber sheet was obtained in the same manner as in Example 6 except that the 25-fold stretched film obtained in Production Example 3 was used instead of the 4-fold stretched film.

Example 8
A vulcanized rubber sheet was obtained in the same manner as in Example 6 except that the 100-fold stretched film obtained in Production Example 4 was used instead of the 4-fold stretched film.

Example 9
A vulcanized rubber sheet was obtained in the same manner as in Example 6 except that the 300-fold stretched film obtained in Production Example 5 was used instead of the 4-fold stretched film.

Example 10
A vulcanized rubber sheet was obtained in the same manner as in Example 6 except that the 500-fold stretched film obtained in Production Example 6 was used instead of the 4-fold stretched film.

Comparative Example 1
The fluororubber 1 obtained in Production Example 7 was subjected to primary vulcanization at 170 ° C. for 10 minutes and further subjected to secondary vulcanization at 230 ° C. for 24 hours to obtain a vulcanized rubber sheet having a thickness of 25 mm × 50 mm × 2 mm.

Comparative Example 2
The fluororubber 2 obtained in Production Example 9 was primarily vulcanized at 180 ° C. for 20 minutes, and further subjected to secondary vulcanization at 290 ° C. for 18 hours to obtain a vulcanized rubber sheet having a thickness of 25 mm × 50 mm × 2 mm.

Comparative Example 3
The PTFE green tape obtained in Production Example 1 and the fluororubber 1 obtained in Production Example 7 obtained in the middle of the production of the biaxially stretched film were superposed and subjected to primary vulcanization at 170 ° C. for 10 minutes, and further at 230 ° C. Secondary vulcanization was performed for 24 hours to obtain a vulcanized rubber sheet having a thickness of 25 mm × 50 mm × 2 mm.

Comparative Example 4
The PTFE green tape obtained in Production Example 1 and the fluororubber 2 obtained in Production Example 9 obtained in the middle of the production of the biaxially stretched film were superposed and subjected to primary vulcanization at 180 ° C. for 20 minutes, and further at 290 ° C. Secondary vulcanization for 18 hours was performed to obtain a vulcanized rubber sheet having a thickness of 25 mm × 50 mm × 2 mm.

Comparative Example 5
Instead of PTFE green tape, a fluororesin fiber body with a thickness of 0.5 mm and a porosity of 77 vol% made from paper made from polytetrafluoroethylene resin fibers (Daikin Industries, Ltd., Polyflon Paper PA-5LH) A vulcanized rubber sheet was obtained by the same method as in Comparative Example 3 except that.

Comparative Example 6
Instead of PTFE green tape, a fluororesin fiber body with a thickness of 0.5 mm and a porosity of 77 vol% made from paper made from polytetrafluoroethylene resin fibers (Daikin Industries, Ltd., Polyflon Paper PA-5LH) ) Was used to obtain a vulcanized rubber sheet by the same method as in Comparative Example 4.

Comparative Example 7
A vulcanized rubber sheet was obtained in the same manner as in Comparative Example 3 except that the fluororesin 1 obtained in Production Example 10 was used instead of the PTFE green tape.

Comparative Example 8
A vulcanized rubber sheet was obtained in the same manner as in Comparative Example 4 except that the fluororesin 1 obtained in Production Example 10 was used instead of the PTFE green tape.

Comparative Example 9
A vulcanized rubber sheet was obtained in the same manner as in Comparative Example 3 except that the fluororesin 2 obtained in Production Example 11 was used instead of the PTFE green tape.

Comparative Example 10
A vulcanized rubber sheet was obtained in the same manner as in Comparative Example 4 except that the fluororesin 2 obtained in Production Example 11 was used instead of the PTFE green tape.

  Evaluation of the fixing strength, surface roughness, and hardness of the obtained sample was performed by the following methods. The results are shown in Table 2.

<Adhesiveness>
The stretched film and fluororubber or fluororesin were adhered and evaluated according to the following criteria.
A: Adhering very firmly and peeling is extremely difficult or impossible.
○: Strongly bonded.
(Triangle | delta): The grade which can peel easily by hand.
X: Not adhered at all.

<Fixing strength>
As shown in FIG. 1, a test sample 2 (20 mm × 15 mm × 2 mm) was placed between two SUS316 plates 1 and allowed to stand at 200 ° C. under a load of 3: 700 g / cm ² for 20 hours. Then, after allowing to cool to room temperature with the load 3 applied, the SUS316 plate 1 was pulled in the shear direction 4 as shown in FIG. 2, and the fixing strength (180 degrees, shear peeling) was measured.

<Surface roughness>
It measured using the surface shape measuring microscope VF-7500 of Keyence Corporation.

<Hardness>
It was measured using a microhardness meter, MICRO IRHD SYSTEM manufactured by Hildebrand Gmbh.

It is explanatory drawing of the processing method of the test piece for the measurement of adhesion strength. It is explanatory drawing of the measuring method of fixation strength.

Explanation of symbols

1 SUS316 plate 2 Test sample 3 Load 4 Shear direction

Claims (6)

A sealing material obtained by laminating a polytetrafluoroethylene porous film obtained by stretching an unfired body or a semi-fired body of polytetrafluoroethylene on the surface of a sealing material body formed of an elastomer. The sealing material according to claim 1, wherein the polytetrafluoroethylene porous film is a polytetrafluoroethylene porous film stretched biaxially. The sealing material according to claim 1 or 2, wherein the elastomer is a fluorine-containing elastomer. The sealing material according to any one of claims 1 to 3, wherein the porosity of the polytetrafluoroethylene porous membrane is 40 to 99%. The sealing material according to any one of claims 1 to 4, wherein the polytetrafluoroethylene porous membrane has a thickness of 5 to 150 µm. The manufacturing method of the sealing material in any one of Claims 1-5 obtained by superposing | stacking an unvulcanized elastomer and a polytetrafluoroethylene porous film, and integrally forming.

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