Daikin Industries, Ltd.

Hirokazu Yukawa

Tetsuo Shimizu

Masamichi Sukegawa

Norimasa Honda

Kazuhide Sawada

Takahisa Aoyama

Mitsuru Kishine

Masayuki Tsuji

Shoji Kawachi

Michio Asano

Keisuke Hagi

Ken Yoshida

Masuo Kokumai

Shingo Tanigawa

Tetsuo Kitahaba

Kenjiro Idemori

Sang Bong Han

Yuuji Tanaka

Taku Yamanaka

Yasuhiko Sawada

Hiroyuki Yoshimoto

Tomihiko Yanagiguchi

Shinichi Yano

Tomohiko Hirata

Yukiharu Nakamura

Yukinaru Nakamura

A polytetrafluoroethylene composition containing polytetrafluoroethylene and fibrous filler. The fibrous filler has an average fiber length of 100 μm or shorter and includes fibers having a fiber length of longer than 160 μm in a proportion of 15% by mass or less.

Polytetrafluoroethylene composition

A method for producing low molecular weight polytetrafluoroethylene which includes: (1) feeding into an airtight container in the absence of oxygen: high molecular weight polytetrafluoroethylene: and a halogenated polymer having a halogen atom other than a fluorine atom; and (2) irradiating the high molecular weight polytetrafluoroethylene to provide low molecular weight polytetrafluoroethylene having a melt viscosity at 380&#xb0; C. of 1.0&#xd7;10to 7.0&#xd7;10Pa&#xb7;s.

Manufacturing method for low molecular weight polytetrafluoroethylene

A resin composition containing a crystalline resin having a melting point of 290&#xb0; C. or higher, a graphite yarn (A) having a crystallite size in a c-axis direction of not greater than 30.0 &#x212b;, and a graphite yarn (B) having a crystallite size in a c-axis direction of greater than 100.0 &#x212b;.

Resin composition

The invention provides a fluororesin composition capable of providing a molded article having low relative dielectric constant, excellent in a temperature stability and causing only small transmission losses. The invention is a fluororesin composition wherein a rate of change in relative dielectric constant between 25&#xb0; C. and 80&#xb0; C. of a molded article produced therefrom under a standard condition is not greater than 0.2%.

Fluororesin composition, fluororesin molded article and method for producing the same

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

Filler-containing polytetrafluoroethylene granular powder, which has a large apparent density, a small average particle size and a sharp particle size distribution and a superior powder flowability, and gives a molded product having a superior tensile strength, elongation and surface roughness, and a process for preparing the same. The granular powder is prepared by granulation of a mixture of a PTFE powder and a filler in water with stirring in the presence of an organic liquid forming liquid-liquid interface with water and a nonionic surfactant.

Filled polytetrafluoroethylene granular powder and process for the production thereof

Granular powder of filled polytetrafluoroethylene and process for the

Polytetrafluoroethylene molding powder which comprises 0.01 to 1% by weight of a perfluoro(vinyl ether) unit and which has a heat of crystallization of 18.0 to 25.0 J/g. The molding powder provides a molded article which has a flex life of not less than 7 million cycles, a creep resistance (total deformation at 200.degree. C.) of not more than 20%, and a creep resistance (total deformation at 25.degree. C.) of not more than 15%. The polytetrafluoroethylene molding powder which is excellent in both creep resistance and flex fatigue resistance is provided as a molding material for parts which are repeatedly bent such as pump.

Polytetrafluoroethylene molding powder

A process for preparing a filler-containing PTFE granular powder, which comprises mixing uniformly a PTFE powder having an average particle size of not more than 100 .mu.m and a (semi-)hydrophilic filler which is surface-treated with an organosilane of the formula: ##STR1## in a two-phase liquid medium comprising water and a water-insoluble organic liquid having a surface tension of not more than 35 dynes/cm at 25.degree. C. Accordingly to the process, the separation of filler can be avoided, and a colorless molded article can be provided.

Process for preparing polytetrafluoroethylene granular powder containing

A uniform mixture of a polytetrafluoroethylene molding powder and an organic filler, which can provide moldings having improved properties without lowering the appearance and mechanical property, is obtained without sticking the filler to the wall of a mixer by mixing the molding powder and the filler in the presence of a silane coupling agent and a polar solvent, or by previously treating the organic filler with the silane coupling agent and mixing the treated filler with the molding powder.

Process for mixing polytetrafluoroethylene molding powder and organic

A process for preparing a PTFE granular powder, which comprises agitating a PTFE powder having an average particle size of not more than 200 .mu.m in a two-phase liquid medium comprising water and at least one halogenated hydrocarbon selected from the group consisting of 1,1-dichloro-2,2,2-trifluoroethane, 1,1-dichloro-2,2,3,3,3-pentafluoropropane and 1,3-dichloro-1,1,2,2,3-pentafluoropropane. The PFTE powder may contain a hydrophilic filler surface-treated with an organosilane or a silicone resin. By using the particular halogenated hydrocarbon, the problemed environmental damage can be reduced, and loss of filler can be decreased.

Process for preparing polytetrafluoroethylene granular power

A molding process for preparing long and thick, large porous PTFE articles comprising preparation steps of a powder for molding which includes a step of gelation of PTFE powder; a pre-forming step by a ram-extrusion; a baking step of the pre-formed article under a non-constrained circumstance; and if necessary, a cooling step; said powder for molding being containing a binder which has a melting point of lower than that of PTFE and does not decompose at a baking temperature of PTFE.

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Settsu, Japan

Hirokazu Yukawa