Ultra thin heat-shrinkable monolayer polyethylene films
US5709932A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 21, 1995 |
| Grant date | Jan 20, 1998 |
| Priority date | — |
| Expiry date | Nov 21, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S428/91
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
This invention relates to a preparation process of a biaxially oriented heat-shrinkable ultra-thin film, biaxially oriented by the flat process and made of linear low-density polyethylene, characterized in that: PA1 an ethylene homopolymer or an ethylene and C.sub.4 to C.sub.18 alpha-olefinic comonomer copolymer of a density lying between 0.89 and 0.94, alone or in combination, are heated beyond the melt temperature and extruded, PA1 the extruded film is poured and cooled at the appropriate hardening temperature, PA1 the film is drawn a first time in the machine direction at the appropriate temperature between 3 and 7 times the initial dimension of the non stretched film, PA1 the film is drawn a second time in the transverse direction at the appropriate temperature between 3 and 15 times the initial dimension of the non stretched film, the biaxially oriented film is drawn a third time in the machine direction at the appropriate temperature between 1.01 and 3 times the dimension after the first draw, PA1 the biaxially oriented film obtained is cooled at room temperature. The invention also concerns an ultra-thin monolayer film obtained notably by such process. These ultra-thin films…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.