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US 5,470,655 AGranted
Polytetrafluoroethylene filamentary material
AssigneeJapan Gore-Tex, Inc.
InventorKengo Hirai
Life of this patent
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Abstract
A filamentary material of polytetrafluoroethylene (PTFE) having an apparent density of 2.0 g/cc or more, tensile strength of 5 grams/denier or more, tensile elongation at break of 15% or more, high axial orientation and high crystalline content is disclosed. The filamentary material, when analyzed by differential scanning calorimetry, exhibits two endothermic peaks; the ratio of the energy defined by the higher temperature peak to the energy defined by the lower temperature peak being equal to or greater than 2.
Claims7
A polytetrafluoroethylene fiber,
- said fiber, when analyzed by differential scanning calorimetry over a temperature range of 30.degree. to 450.degree. at a heating rate of 10.degree. C./minute, exhibiting a first endothermic peak in the temperature range 325.degree. to 350.degree. C. and a second endothermic peak in the temperature range 370.degree. to 390.degree. C.;
- a melt energy ratio of the second peak to that of the first peak being equal to or greater than 2.
A polytetrafluoroethylene fiber;
- said fiber comprising polytetrafluoroethylene resin having a standard specific gravity of 2.20 or less.
- said fiber formed by stretching a precursor fiber having an apparent density of 1.8 grams/cc or less at a stretch rate of 10%/second or less, at a temperature of 320.degree. C. or less;
- said fiber, when analyzed by differential scanning calorimetry over a temperature range of 30.degree. to 450.degree. C. at a heating rate of 10.degree. C./minute, exhibiting a first endothermic peak in the temperature range 325.degree. to 350.degree. C. and a second endothermic peak in the temperature range 370.degree. to 390.degree. C.;
- a melt energy ratio of the second peak to that of the first peak being equal to or greater than 2.
1 more element
Dependencies are inferred from the claim text.