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EP0113869A2
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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
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
2026-11-01 07:07
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.
References Cited (Backward Citations)
No citation records indexed.
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