Process for making porous membranes
First Claim
1. A process for the preparation of porous polymeric membranes comprising,a) forming a solution of a polymer in a solvent for the polymer;
- b) adding a nonsolvent to the polymer solution until a thermodynamically unstable polymer solution is obtained;
c) separately spraying the unstable polymer solution and nonsolvent from separate spray means onto a sliding and rotating mandrel means to form a precipitated material; and
d) placing the precipitated material into a bath of nonsolvent to cure the precipitated material.
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Accused Products
Abstract
Porous, distensible, gel-like membranes which in tubular form are suitable as implants, e.g., vascular prostheses and a process for the preparation thereof. The membranes are formed by a spraying, phase-inversion technique which employs thermodynamically unstable polymer solutions and is accomplished by separately spraying the unstable solution and a nonsolvent onto a rotating surface. Prostheses from the highly porous tubular membranes have shown a high degree of patency and completeness of the healing process and are useful for direct implantation in the body or for extracorporeal vascular accesses.
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Citations
13 Claims
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1. A process for the preparation of porous polymeric membranes comprising,
a) forming a solution of a polymer in a solvent for the polymer; -
b) adding a nonsolvent to the polymer solution until a thermodynamically unstable polymer solution is obtained; c) separately spraying the unstable polymer solution and nonsolvent from separate spray means onto a sliding and rotating mandrel means to form a precipitated material; and d) placing the precipitated material into a bath of nonsolvent to cure the precipitated material. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification