Biaxially stretched multilayer film and process for manufacturing same
US5271976A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Apr 19, 1991 |
| Grant date | Dec 21, 1993 |
| Priority date | — |
| Expiry date | Apr 19, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/3192
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A tubular multilayer film including at least two, biaxially stretched tubular layers each formed of a polypropylene resin, wherein the innermost layer contains spherical antiblocking agent particles having an average particle size of 0.2 to 5 .mu.m in an amount of 0.1 to 0.7% by weight, and the outermost layer is free of the spherical antiblocking agent particles is disclosed. The multilayer film may be prepared by biaxially stretching a multilayer tubular raw sheet having an innermost polypropylene layer containing spherical antiblocking agent particles and an outermost polypropylene layer free of such antiblocking agent particles.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.