Method of making controlled porosity expanded polytetrafluoroethylene products
US5433909A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 12, 1993 |
| Grant date | Jul 18, 1995 |
| Priority date | — |
| Expiry date | Mar 12, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31544
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A method of forming porous articles with a varying pore distribution by extrusion from a billet with a varying lubricant distribution. A single-polymer polytetrafluoroethylene is extruded and then stretched and sintered to provide a differential porous PTFE structure composed of fibers and nodes connected to one another by these fibers. The microfibrous structure has a portion within the cross-section that possesses a different pore size, accompanied by a different node and fiber geometry, than adjacent areas within that cross section. In a vascular graft, the pores taper inwardly, providing a fluid-tight lumen wall structure that prevents leakage, yet promotes cellular ingrowth and natural tissue regeneration. A node structure of radially-oriented plates provides flexibility, suture strength, and enhanced protection against collapse.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.