Methods of making stretched filled microporous films
US6179939A · kind A · utility
24Cited by
47References
56Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | May 12, 1997 |
| Grant date | Jan 30, 2001 |
| Priority date | — |
| Expiry date | May 12, 2017 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29K2105/16
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Breathable barriers, comprising a thermoplastic polymer and at least 30% by weight filler, are stretched in one direction in multiple discrete steps wherein the strain rate of each discrete stretching step is less than about 100,000%/minute and wherein the line speed of the last stretching step is in excess of 500 feet per minute. The resulting films may be stretched, as a result of the cumulative discrete stretching operations, from about 2 to 7 times its original length in order to create a breathable barrier having a WVTR in excess of 800 g/m.sup.2 /day and a hydrohead of at least 60 cm.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.