Heat-sealable packaging film producing a peelable seal
US4367312A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 7, 1980 |
| Grant date | Jan 4, 1983 |
| Priority date | — |
| Expiry date | Aug 7, 2000 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31928
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Heat-sealable packaging film producing a peelable seal, process for the preparation thereof and packages made therefrom or comprising such a film. This film produces such a seal on a wide range of packaging films, including polyester, polyvinyl chloride, polyamide and polyacrylonitrile films owing to: PA0 1. its chemical composition which comprises: PA1 (a) 55 to 95% by weight of at least one ethylene polymer selected from polyethylene having a density of from 0.91 to 0.93 g/cm.sup.3 and an ethylene-vinyl acetate copolymer containing at most 10% by weight of vinyl acetate, PA1 (b) 5 to 30% by weight of polystyrene, and PA1 (c) 0 to 20% by weight of a thermoplastic, elastomeric styrene-butadiene-styrene or styrene-isoprene-styrene block copolymer, and PA0 2. the fact that that face of the film which is intended to form the peelable seal, has a surface tension of from 35 to 50, preferably of 37 to 45 millinewtons per meter. The film is prepared by extrusion followed by a corona discharge pretreatment of said face.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.