Abstract: This invention provides a polytetrafluoroethylene powder capable of giving moldings which are improved in surface roughness Ra, tensile strength and/or tensile elongation as compared with the prior art ones and can be excellent in dielectric breakdown strength and, further, can be excellent, if desired, in apparent density and/or powder flowability as well, and a method of producing a polytetrafluoroethylene molding powder. The present invention is a PTFE powder wherein a surface roughness Ra of molded articles a1 for measurement is less than 0.92 ?m.

Abstract: There is provided a process for producing hexafluoropropylene oxide which is novel and capable of achieving a higher yield. An organic phase comprising hexafluoropropylene (HFP) in an organic solvent and an aqueous phase comprising an oxygen-containing oxidizing agent in water are supplied to a small space (or microspace), preferably together with a phase transfer catalyst. The organic phase and the aqueous phase are contacted with each other in the small space, thereby reacting hexafluoropropylene (HFP) with the oxygen-containing oxidizing agent, preferably by an action of the phase transfer catalyst to give hexafluoropropylene oxide (HFPO). After the reaction, the organic phase and the aqueous phase are taken out from the small space to obtain an organic phase comprising the hexafluoropropylene oxide (HFPO).

Abstract: This invention provides a polytetrafluoroethylene powder capable of giving moldings which are improved in surface roughness Ra tensile strength and/or tensile elongation as compared with the prior art ones and can be excellent in dielectric breakdown strength and, further, can be excellent, if desired, in apparent density and/or powder flowability as well, and a method of producing a polytetrafluoroethylene molding powder. The present invention is a PTFE powder wherein a surface roughness Ra of molded articles a1 for measurement is less than 0.92 ?m.

Abstract: The present invention provides a polytetrafluoroethylene molded article, particularly a PTFE molded article for high-frequency insulation, which is excellent in various electric properties and mechanical properties in a high frequency range of 3 to 30 GHz. The present invention also provides PTFE fine powder, which is excellent in extrusion moldability and capable of providing the molded article, and a process for preparing the same. More specifically, the present invention relates to a polytetrafluoroethylene fine powder having a standard specific gravity of 2.180 to 2.225, which is obtained by contacting polytetrafluoroethylene fine powder having a standard specific gravity of 2.180 to 2.225 with a fluorine radical source, wherein tan? at 12 GHz of a film comprising the powder, which is obtained by cooling at 5 to 50° C./second after baking, is at most 2.0×10?4.

Abstract: An electrode additive comprising an aqueous fluoropolymer dispersion, wherein the aqueous fluoropolymer dispersion is stabilized by the use of a surfactant that does not substantially remain in an electrode coating film after a drying step during electrode production.

Abstract: The present invention provides a TFE resin molding material which has electric characteristics, particularly low dielectric dissipation factor, in a microwave area, can also lower extrusion pressure as the material is of low molecular weight and can provide a molded article excellent in surface smoothness. The material is especially useful as a coating material for a coaxial cable for equipment in which microwave is used, including satellite transmitting equipment and a cell phone base station. A tetrafluoroethylene resin molding material excellent in high frequency electric characteristics, which provides a molded article having a dielectric constant of at most 2.2 and a dielectric dissipation factor of at most 1.60×10?4 under 12 GHz, and a standard specific gravity of at least 2.192 and less than 2.3 is provided. As the tetrafluoroethylene resin, a tetrafluoroethylene homopolymer or a copolymer of 99.9 to 99.9999% by mole of tetrafluoroethylene and 0.0001 to 0.1% by mole of a specific fluoromonomer is used.

Abstract: A seal ring with a sliding surface, which is obtained by molding a molding powder or granulated powder of non-melt-moldable modified polytetrafluoroethylene containing 0.01 to 1% by weight of a perfluorovinylether unit represented by the formula (I): —CF2—CF(—O—X)—??(I) wherein X represents a perfluoroalkyl group having 1 to 6 carbon atoms or a perfluoroalkoxyalkyl group having 2 to 9 carbon atoms, the modified polytetrafluoroethylene having a heat of crystallization of 18 to 25J/g measured by a differential scanning calorimeter.

Abstract: There is provided a fluorine-containing polymer latex providing a fluorine-containing polymer material being excellent in mechanical properties of a molded article. The preparation process comprises emulsion-polymerizing a fluorine-containing olefin solely or a fluorine-containing olefin and other monomer in an aqueous medium in the presence of at least one of fluorine-containing surfactants represented by the formula (I): F(CF2?mO—(CF(X)CF2—O?nCF(X)COOM wherein X is fluorine atom or a linear or branched lower perfluoroalkyl group; —COOM is a carboxylic acid salt; m is an integer of from 3 to 10; n is 0, 1 or 2. There are also provided a molding material and dispersion comprising a tetrafluoroethylene/hexafluoropropylene copolymer, polytetrafluoroethylene or fluoro elastomer which are obtained by the above-mentioned preparation process.

Abstract: This invention provides a polytetrafluoroethylene powder capable of giving moldings which are improved in surface roughness Ra, tensile strength and/or tensile elongation as compared with the prior art ones and can be excellent in dielectric breakdown strength and, further, can be excellent, if desired, in apparent density and/or powder flowability as well, and a method of producing a polytetrafluoroethylene molding powder. The present invention is a PTFE powder wherein a surface roughness Ra of molded articles a1 for measurement is less than 0.92 ?m.

Abstract: The present invention provides a TFE resin molding material which has electric characteristics, particularly low dielectric dissipation factor, in a microwave area, can also lower extrusion pressure as the material is of low molecular weight and can provide a molded article excellent in surface smoothness. The material is especially useful as a coating material for a coaxial cable for equipment in which microwave is used, including satellite transmitting equipment and a cell phone base station. A tetrafluoroethylene resin molding material excellent in high frequency electric characteristics, which provides a molded article having a dielectric constant of at most 2.2 and a dielectric dissipation factor of at most 1.60×10−4 under 12 GHz, and a standard specific gravity of at least 2.192 and less than 2.3 is provided. As the tetrafluoroethylene resin, a tetrafluoroethylene homopolymer or a copolymer of 99.9 to 99.9999% by mole of tetrafluoroethylene and 0.0001 to 0.

Abstract: The present invention provides a polytetrafluoroethylene molded article, particularly a PTFE molded article for high-frequency insulation, which is excellent in various electric properties and mechanical properties in a high frequency range of 3 to 30 GHz. The present invention also provides PTFE fine powder, which is excellent in extrusion moldability and capable of providing the molded article, and a process for preparing the same. More specifically, the present invention relates to a polytetrafluoroethylene fine powder having a standard specific gravity of 2.180 to 2.225, which is obtained by contacting polytetrafluoroethylene fine powder having a standard specific gravity of 2.180 to 2.225 with a fluorine radical source, wherein tan &dgr; at 12 GHz of a film comprising the powder, which is obtained by cooling at 5 to 50° C./second after baking, is at most 2.0×10−4.

Abstract: To provide a granular PTFE powder having a low electrostatic charging property even after drying. A process for preparing a low-electrostatically-charging granular polytetrafluoroethylene powder by contacting a polar group-containing organic compound having an electrostatic charging-preventing ability when substantially dry to a granular polytetrafluoroethylene powder and then drying the granular powder while the polar group-containing organic compound is kept remaining in the granular powder.

Abstract: There is provided a resin powder for molding which comprises 35 to 98% by weight of a polytetrafluoroethylene powder having an average particle size of not more than 120 &mgr;m, 35 to 2% by weight of a heat resistant aromatic polyoxybenzoyl ester resin powder subjected to water repelling treatment and 30 to 0% by weight of an inorganic filler, has an apparent density of not less than 0.6 g/cm3 and an average particle size of not more than 800 &mgr;m, and provides a molded article having an elongation at break of not less than 20%. The resin powder for molding is free from separation of a filler, has excellent flowability and apparent density which are important characteristics in handling the powder, and can provide a PTFE molded article having a high elongation which has not been obtained.

Abstract: The present invention relates to a seal ring comprising 40 to 94% by weight of polytetrafluoroethylene powder and 6 to 60% by weight of aromatic polyoxybenzoylester heat resistant resin powder or 40 to 94% by weight of polytetrafluoroethylene powder, 3 to 30% by weight of aromatic polyoxybenzoylester heat resistant resin powder and 3 to 30% by weight of molybdenum disulfide powder or 3 to 30% by weight of tungsten disulfide powder. The seal ring has little deformation by bulging of the seal even when used under pressure, can restrict the abrasion of a contacting material even when made of soft metal, providing a stable sealing effect over a long period. Furthermore, the seal ring is low in friction and change in sliding torque and therefore can significantly improve control and response of a device equipped with the seal ring.

Abstract: An electrode additive comprising an aqueous fluoropolymer dispersion, wherein the aqueous fluoropolymer dispersion is stabilized by the use of a surfactant that does not substantially remain in an electrode coating film after a drying step during electrode production.

Abstract: To provide a filler-containing PTFE granular powder for molding, which has a high apparent density, a small electrostatic charge and excellent flowability and gives a molded article which is free from lowering of tensile strength and elongation and coloring attributable to a surfactant. Also a process for preparing the granular powder is provided. The granulation is carried out by wetting 100 parts by weight of a mixture of a PTFE powder and filler with 30 to 60 parts by weight of an aqueous solution containing an anionic surfactant in a concentration of not less than 10 times and less than 40 times the critical micelle concentration and then applying mechanical force to the mixture.

Abstract: A seal ring which contains a scaly graphite powder essentially alone as a filler, and comprises 2 to 35% by weight of the graphite powder and 65 to 98% by weight of a polytetrafluoroethylene powder, wherein the graphite powder has an interplanar spacing of 0.335 to 0.340 nm, as measured by the powder X-ray diffraction method, and a size of a crystallite of (004) face of at least 70 nm is provided. Since deformation and extrusion of the seal ring are kept small even under a high pressure, and the abrasion of the opposite material can be prevented even if it is made of a soft metal, it is possible to maintain a stable sealing effect for a longer period of time. In addition, since the seal ring has small sliding resistance, handling property, response of the sealing device and suitability for fitting to the device can be largely improved. Thus, the seal ring is suitable for the valve device of power steering of automobiles, automatic transmission or shock absorber.

Abstract: There is provided a seal ring which is excellent since the seal ring has a high durability under sliding at high pressure during a long-term use, and a necessary suitability for fitting. The seal ring can provide an effect of sealing oil stably for a long period of time, and possesses properties suitable particularly for a seal ring of endless type.

Abstract: There is provided a resin powder for molding which comprises 35 to 98% by weight of a polytetrafluoroethylene powder having an average particle size of not more than 120 &mgr;m, 35 to 2% by weight of a heat resistant aromatic polyoxybenzoyl ester resin powder subjected to water repelling treatment and 30 to 0% by weight of an inorganic filler, has an apparent density of not less than 0.6 g/cm3 and an average particle size of not more than 800 &mgr;m, and provides a molded article having an elongation at break of not less than 20%. The resin powder for molding is free from separation of a filler, has excellent flowability and apparent density which are important characteristics in handling the powder, and can provide a PTFE molded article having a high elongation which has not been obtained.

Abstract: A seal ring comprising 40 to 94% by weight of a polytetrafluoroethylene powder, 3 to 30% by weight of a heat resistant aromatic polyoxybenzoyl ester resin powder and 3 to 30% by weight of a graphite powder. A stable sealing effect can be obtained for a long period of time since a deformation of the seal ring is small for the use even under a high pressure and an abrasion of an opposite material can be inhibited even if the opposite material is a soft metal. Further a frictional force is small, and a change in a sliding torque is small. Therefore the seal ring is suitable as a seal ring for a power steering where operability and response of the sealing device can be enhanced and also as a seal ring for an automatic transmission which slides at high revolutions and as a seal ring for a shock absorber which is required to have a sealing property under reciprocating sliding environment.