Composite polytetrafluoroethylene article and a process for making the same
AssigneeW. L. Gore & Associates, Inc.
InventorJeffery B. Bowman
Life of this patent
Estimating the term…
Abstract
A porous polytetrafluoroethylene (PTFE) article which is made up of a number of smaller articles with a microstructure of nodes interconnected by fibrils, these articles having been joined to one another such that their microstructure is virtually unaltered across the join. A process for producing such a PTFE article by closely abutting small-shaped PTFE segments and applying a force perpendicular to the seam while heating to a temperature above the crystalline melt point of the segments.
Claims4
A process for joining a plurality of shrinkable expanded porous polytetrafluoroethylene segments, each having a microstructure of nodes interconnected by fibrils, such that the microstructure is virtually uninterrupted at the seam joining said segments, comprising the steps of:
- (a) arranging said segments such that their edges are disposed in abutting relationship;
- (b) causing a pressure to be applied perpindicular to said abutting edges;
- (c) causing said segments to be restrained from shrinking in any direction;
- (d) heating said segments while they are so held, to a temperature above the crystalline melt point of polytetrafluoroethylene for a predetermined time;
- and
- (e) allowing said segments to cool while still being held restrained and under pressure.
A method for manufacturing a porous composite tube from a plurality of segments of shrinkable expanded porous polytetrafluoroethylene, each having a microstructure of nodes interconnected by fibrils such that the microstructure is virtually uninterrupted at the seam joining said segments comprising the steps of:
- (a) forming a tube of expanded porous polytetrafluoroethylene segments by disposing said segments around a suitable mandrel in abutting relationship;
- (b) winding a film of high strength shrinkable expanded porous polytetrafluoroethylene with a microstructure of nodes interconnected by fibrils around said segments;
- (c) restraining said segments from shrinking longitudinally;
- (d) bonding and shrinking said film to said segment, thereby applying pressure perpindicular to the edge of said segments by heating to a temperature above the crystalline melt point of polytetrafluoroethylene for a predetermined time;
- and
- (e) allowing said wrapped bonded segments to cool.
Dependencies are inferred from the claim text.