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Patent EP0113869A2 successfully refreshed from Google Patents.
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EP0113869A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Porous polytetrafluoroethylene material

Assignee: Daikin Industries Ltd
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Filing: 1983-12-10
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Granted: —
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Expires: 2003-12-10
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Abstract

Abstract A porous polytetrafluoroethylene material produced by forming a mixture of an adequate amount of a liquid lubricant and polytetrafluoroethylene fine powder having an average molecular weight of at least 6,000,000, an amorphous index larger than 0.1 and a number average primary particle size of 0.1 to 0.8 microns, and a clear endothermic peak at a temperature of 347±3°C and an another endothermic peak or shoulder at a temperature between 330 °C and the temperature of said clear endothermic peak on a crystalline melting chart recorded by a differential scanning calorimeter, removing the lubricant to obtain an unsintered PTFE material and expanding the unsintered polytetrafluoroethylene material at least monoaxially at a temperature higher than the melting point of polytetrafluoroethylene.

Inventors

  • 👤 Yasuhiro Moriyama
  • 👤 Shoji Suzuki
  • 👤 Atsuo Yoshimura
  • 👤 Kanji Kawakami
  • 👤 Jyuzaemon Hoashi
  • 👤 Syozo Fumoto
  • 👤 Kiyoshi Oshita

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-28 16:52
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/18; B; B29; B29C; B29C55/00; B29C55/005; B29C67/00; B29C67/20; B29C67/202; C08J9/00; C08J9/28; B29K; B29K2027/00; B29K2027/12; B29K2027/18; B29K2105/00; B29K2105/04; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/18; Y; Y10; Y10S; Y10S521/00; Y10S521/919

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 116 words
A porous polytetrafluoroethylene material produced by forming a mixture of an adequate amount of a liquid lubricant and polytetrafluoroethylene fine powder having an average molecular weight of at least 6,000,000, an amorphous index larger than 0.1 and a number average primary particle size of 0.1 to 0.8 microns, and a clear endothermic peak at a temperature of 347±3°C and an another endothermic peak or shoulder at a temperature between 330°C and'the temperature of said clear endothermic peak on a crystalline melting chart recorded by a differential scanning calorimeter, removing the lubricant to obtain an unsintered PTFE material and expanding the unsintered polytetrafluoroethylene material at least monoaxially at a temperature higher than the melting point of PTFE.
Claim 2
Dependent Claim 116 words
A porous polytetrafluoroethylene material produced by forming a mixture of an adequate amount of a liquid lubricant and polytetrafluoroethylene fine powder having an average molecular weight of at least 6,000,000, an amorphous index larger than 0.1 and a number average primary particle size of 0.1 to 0.8 microns, and a clear endothermic peak at a temperature of 347±3°C and an another endothermic peak or shoulder at a temperature between 330°C and'the temperature of said clear endothermic peak on a crystalline melting chart recorded by a differential scanning calorimeter, removing the lubricant to obtain an unsintered PTFE material and expanding the unsintered polytetrafluoroethylene material at least monoaxially at a temperature higher than the melting point of PTFE.
Claim 3
Dependent Claim 20 words
A porous polytetrafluoroethylene material according to claim 1, wherein the molecular weight of the fine powder is at least 6,500,000.
Claim 4
Dependent Claim 20 words
A porous polytetrafluoroethylene material according to claim 1, wherein the amorphous index of the fine powder is larger than 0.11.
Claim 5
Dependent Claim 23 words
A porous polytetrafluoroethylene material according to claim 1, wherein the endothermic ratio as defined hereinbefore of the fine powder is larger than 0.30.
Claim 6
Dependent Claim 27 words
A porous polytetrafluoroethylene material according to claim 1, wherein the critical thickness of devirification of the film formed from the fine powder is 20 to 45 microns.
Claim 7
Dependent Claim 59 words
A porous polytetrafluoroethylene material according to claim 1, wherein the fine powder is prepared by emulsion polymerizing tetrafluoroethylene in an aqueous medium in the presence of an anionic surfactant, an'emulsion stabilizer which is liquid under the polymerization conditions and a water-soluble polymerization initiator, at a temperature of lower than 20°C under a pressure of 5 to 20 Kg/c m2.

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