Polyetrafluoroethylene compositions
AssigneeW. L. Gore & Associates, Inc.
InventorPhillip A. Branca
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Abstract
In the present invention a blend of resin composition and blending technique is optimized to provide a desired balance of node size and fibril length with the additional property of thermal stability in the resulting stretched material. The stretched blend can be described as a polytetrafluoroethylene porous material having a microstructure of nodes interconnected by fibrils in which the material comprises a blend of two different polytetrafluoroethylenes, one polytetrafluoroethylene being a homopolymer of tetrafluoroethylene and the other polytetrafluoroethylene being a modified polymer of tetrafluoroethylene.
Claims10
A stretched porous polytetrafluoroethylene having a microstructure of nodes interconnected by fibrils in which the material comprises a mixture of two different polymers, one polymer being polytetrafluoroethylene homopolymer and the other polymer being a non-resilient modified polytetrafluoroethylene polymer in which the polymer contains units of a comonomer in an amount insufficient to cause the polymer to become melt-processible.
Process for preparing a porous polytetrafluoroethylene material which comprises the steps in sequence of:
- (a) forming an aqueous dispersion of a polytetrafluoroethylene homopolymer and a non-resilient modified polytetrafluoroethylene polymer in which the modified polymer contains units of a comonomer in an amount insufficient to cause the polymer to become melt-processible;
- (b) coagulating the solids from the dispersion;
- (c) lubricating and paste extruding the coagulated material;
- and
- (d) stretching the material.
Dependencies are inferred from the claim text.