Process of making stretchable, heat shrinkable polyethylene film
US5132074A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 15, 1989 |
| Grant date | Jul 21, 1992 |
| Priority date | — |
| Expiry date | Aug 15, 2009 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2323/08
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A stretchable, heat shrinkable ethylene-.alpha.-olefin copolymer film which has excellent stretchability as well as shrinkability at a low temperature and is useful as a good packaging material is prepared by melt extruding a composition including at least one ethylene-.alpha.-olefin copolymer as a main component to give a non-stretched film and biaxially stretching the film in a temperature region where an orientation can be induced and at an area stretching ratio of not less than 8 under conditions such that a tensile strength is from 30 to 170 kg/cm.sup.2. The film has an index of refraction N of 1.500 to 1.522, a degree of orientation Wk according to X-ray diffraction method of 0.78 to 0.93 and an area shrinkage of not less than 15% at 90.degree. C.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.