Daikin Industries, Ltd.

Shinichi Yano

Yoshinori Nanba

Hiroyuki Yoshimoto

Tetsuo Shimizu

Makoto Ono

Michio Asano

Shunji Kasai

Katsutoshi Yamamoto

Masamichi Sukegawa

Kazutaka Hosokawa

Tomihiko Yanagiguchi

Hirokazu Yukawa

Kazuo Ishiwari

Tatsuro Uchida

It is an object of the present invention to obtain a PTFE molding excellent in flexing resistance without decreasing the tensile strength and tensile elongation. The present invention is a modified polytetrafluoroethylene molded article obtained by molding a modified polytetrafluoroethylene molding powder, wherein the modified polytetrafluoroethylene molding powder is not melt-moldable, the modified polytetrafluoroethylene constituting the modified polytetrafluoroethylene molding powder contains 0.01 to 1% by mass of a perfluorovinyl ether unit represented by the formula (I): (wherein X is a perfluoroalkyl group containing 1 to 6 carbon atoms or a perfluoroalkoxyalkyl group containing 4 to 9 carbon atoms) and the heat of crystallization thereof is 18.0 to 25.0 J/g as measured using a differential scanning calorimeter, and the modified polytetrafluoroethylene molded article has a heat of fusion of not more than 28 J/g and a flex life of at least 200&#xd7;10cycles.

Modified polytetrafluoethylene molded article and process for manufacture thereof

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&#x3b4; at 12 GHz of a film comprising the powder, which is obtained by cooling at 5 to 50&#xb0; C./second after baking, is at most 2.0&#xd7;10.

Polytetrafluoroethylene fine powder of particular specific standard gravity, polytetrafluoroethylene formed article prepared from the same and method for preparation of the same

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&#xd7;10under 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.

Tetrafluoroethylene based resin molding material excellent in high frequency electric characteristics

A polytetrafluoroethylene mixed powder, which is obtained by mixing low molecular weight polytetrafluoroetylene powder and high molecular weight polytetrafluoroethylene powder obtained by emulsion polymerization of tetrafluoroethylene, wherein the low molecular weight polytetrafluoroetylene powder has a number average molecular weight of 1,000,000&#xb1;500,000 and a maximum peak temperature of 327&#xb1;5&#xb0; C. in the endothermic curve appearing on the crystalline melting curve obtained by using a differential scanning calorimeter, the high molecular weight polytetrafluoroetylene powder has a number average molecular weight of 4,500,000&#xb1;1,000,000 and a maximum peak temperature of 340&#xb1;7&#xb0; C. in the endothermic curve appearing on the crystalline melting curve obtained by using a differential scanning calorimeter, and the mixed powder has evident peak temperatures of 327&#xb1;5&#xb0; C. and 340&#xb1;7&#xb0; C. in the endothermic curve appearing on the crystalline melting curve obtained by using a differential scanning calorimeter.

Polytetrafluoroethylene mixed powder used for insulation of product for high frequency signal transmission and product for high frequency signal transmission using the same

In the preparation of a modified polytetrafluoroethylene fine powder by polymerizing tetrafluoroethylene in an aqueous medium in the presence of a water soluble fluorine-containing dispersant, a fluoroalkyl vinyl ether is added to a reaction system at latest at a start of a reaction and a copolymerization reaction of the fluoroalkyl vinyl ether with tetrafluoroethylene is initiated, and a chain transfer agent is added to the reaction system after at least 80% of tetrafluoroethylene to be polymerized is consumed. The obtained modified polytetrafluoroethylene fine powder has good molding properties, in particular, extrusion properties, and high heat resistance.

Modified polytetrafluoroethylene fine powder and process for preparing the same

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Settsu, Japan

Shinichi Yano