Process of manufacturing porous multi-expanded fluoropolymers
First Claim
Patent Images
1. A process of preparing a polytetrafluroethylene-elastomer microporous substrate comprising the steps of:
- forming said substrate from a blend of polytetrafluoroethylene and an elastomer;
heating said substrate to a temperature, and for a period of time which will not cause said elastomer to become cured;
expanding said heated substrate to a first expanded position;
maintaining said substrate in said first expanded position;
heating said substrate to a temperature for a sufficient period of time for curing said elastomer but that will not effect sintering of said polytetrafluoroethylene;
raising the temperature of said substrate for a sufficient period of time to flash sinter said polytetrafluoroethylene while allowing the substrate to assume a second expanded position.
2 Assignments
0 Petitions
Accused Products
Abstract
Interpenetrated matrix of polytetrafluoroethylene and elastomer is disclosed. The matrix is formed into a composite material which is flexible, durable, highly porous with a tight microporous structure and improved retractability. The composite material is subjected to a multi-expansion process to produce shaped articles such as films, tubes, rods and filaments with excellent flexibility and elasticity. More particularly, the composite material can be utilized to produce vascular grafts with excellent biological compatibility.
168 Citations
23 Claims
-
1. A process of preparing a polytetrafluroethylene-elastomer microporous substrate comprising the steps of:
-
forming said substrate from a blend of polytetrafluoroethylene and an elastomer; heating said substrate to a temperature, and for a period of time which will not cause said elastomer to become cured; expanding said heated substrate to a first expanded position; maintaining said substrate in said first expanded position; heating said substrate to a temperature for a sufficient period of time for curing said elastomer but that will not effect sintering of said polytetrafluoroethylene; raising the temperature of said substrate for a sufficient period of time to flash sinter said polytetrafluoroethylene while allowing the substrate to assume a second expanded position. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. A process of forming a vascular graft comprising the steps of:
-
forming a tubular structure from a blend of polytetrafluoroethylene and at least one elastomer; heating said tubular structure to a temperature below said elastomer curing temperature; expanding said tubular structure to a first expanded state; maintaining said tubular structure in said first expanded state; curing said elastomer; and flash sintering said polytetrafluoroethylene while allowing said tubular structure to assume a second expanded position. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
-
Specification