Daikin Industries, Ltd.

Daiken Industries, Ltd.

Michio Asano

Tetsuo Shimizu

Masamichi Sukegawa

Shoji Kawachi

Masayuki Tsuji

Shingo Tanigawa

Makoto Ono

Yoshinori Nanba

Hiroyuki Yoshimoto

Shunji Kasai

Kazuya Kawahara

Hirokazu Yukawa

Shinichi Yano

Tadashi Ino

Kenji Ichikawa

Tomihiko Yanagiguchi

Singo Tanigawa

Akira Shimodoh

Tetuo Shimizu

Shiouji Kawachi

Takatomo Nishino

Kenji Futatsugi

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 &#x3bc;m.

PTFE powder and method of producing PTFE molding powders

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

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.

Electrode additive

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 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):&#x2014;CF&#x2014;CF(&#x2014;O&#x2014;X)&#x2014;&#x2003;&#x2003;(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.

Seal ring

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.

Low-electrostatically-charging granular polytetrafluorethylene powder and preparation process of same

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/cm 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.

Resin powder for molding and preparation process of same

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.

Filler-containing polytetrafluoroethylene granular powder for molding and preparation process of same

To provide a PTFE granular powder containing no filler which has a large apparent density, a small average particle size, a narrow particle size distribution, a small electrostatic charge, a small angle of repose and an excellent powder flowability, and a process for preparing the same. The granular powder is prepared by granulation of a PTFE powder in water with stirring in the presence of an organic liquid forming liquid-liquid interface with water and a nonionic and/or anionic surfactant. A molded article obtained from the granular powder is excellent in tensile strength and elongation and has a small surface roughness, a high electrostatic charge and a high whiteness (Z value).

Filler-free granular polytetrafluoroethylene powder and process for producing the same

Filler-containing polytetrafluoroethylene granular powder, which has a large apparent density, a small average particle size, a narrow particle size distribution, a superior powder flowability, a small electrostatic charge and gives a molded product having a superior tensile strength and elongation a high degree of whiteness and a low surface roughness, and a process for preparing the same. The granulation is carried out by stirring, in water, of a PTFE powder and a filler in the presence of an organic liquid forming liquid-liquid interface with water and an anionic surfactant and/or nonionic surfactant such as a segmented polyalkylene glycol having a hydrophobic segment and hydrophilic segment and deagglomerating of the powder.

Filled particulate powder of polytetrafluoroethylene and process for preparing the same

To provide a filler-containing or non-filler-containing polytetrafluoroethylene granular powder having a high apparent density, a small electrostatic charge and a superior powder flowability and giving a molded product which is free from lowering of tensile strength and elongation and coloring attributable to the surfactant and has a high degree of whiteness, and a process for preparing the same. The granulation is carried out by wetting 100 part by weight of a polytetrafluoroethylene powder or a mixture of polytetrafluoroethylene powder and filler with 30 to 60 parts by weight of an aqueous solution containing a nonionic surfactant having a hydrophobic segment comprising a poly(oxyalkylene) unit having 3 or 4 carbon atoms and a hydrophilic segment comprising a poly(oxyethylene) unit and then applying a mechanical force to the wetted polytetrafluoroethylene powder or the wetted mixture of polytetrafluoroethylene powder and filler.

Granular polytetrafluoroethylene powders and process for producing the same

To provide a method of shaping a granular polytetrafluoroethylene powder, in which a powder flowability can be enhanced and an apparent density can be increased without substantially changing an average particle size and particle size distribution of the powder. The granular polytetrafluoroethylene powder having an average particle size of 100 to 800 &mgr;m is subjected to shaping by using a rotating-type stirring vessel with two cross axes.

Method for spherizing granular polyetrafluoroethylene powder

To provide a filler-containing PTFE granular powder, which has a large apparent density, a small average particle size, a narrow particle size distribution, a superior powder flowability and a small electrostatic charge, and gives a molded product having a superior tensile strength and elongation, a lower surface roughness and a high whiteness, and a process for preparing the same. The granular powder is prepared by forming a PTFE powder and a filler into an aqueous slurry by using an organic liquid forming liquid-liquid interface with water and a nonionic surfactant having a hydrophobic segment and a hydrophilic segment, and then granulating in combination of stirring and deagglomerating.

Filled granular polytetrafluoroethylene powder

To provide a modified PTFE granular powder which has a large apparent density, a small average particle size, a narrow particle size distribution, an electrostatic charge substantially approximate to zero, a small angle of repose and being excellent in powder characteristics, particularly particle stability. The modified PTFE powder is granulated with stirring in water under coexistence of an organic liquid which forms liquid-liquid interface with water and a nonionic surfactant of segmented polyalkylene glycols which has a hydrophobic segment and a hydrophilic segment. A molded article obtained from the granular powder is excellent in tensile strength and elongation and has a small surface roughness, a large break down voltage and a large whiteness (Z value).

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Settsu, Japan

Michio Asano