Method of forming a porous polyolefin film
US4921653A · kind A · utility
58Cited by
4References
12Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Nov 2, 1988 |
| Grant date | May 1, 1990 |
| Priority date | — |
| Expiry date | Nov 2, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S264/47
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A gas-permeable porous film which is prepared by stretching a film made from a mixture containing a polyolefin resin and an inorganic filler at least uniaxially and possesses a rugged pattern on its surface. One process for producing the film comprises forming the aforesaid mixture into a film, providing on the surface of the film a rugged pattern, stretching the resulting film at least uniaxially, and forming on the stretched film thus-formed a rugged pattern by means of a heated emboss roll and simultaneously allowing the stretched film to contract.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.