Packages embodying a controlled peel seal and method of preparing same
US4252846A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 22, 1975 |
| Grant date | Feb 24, 1981 |
| Priority date | — |
| Expiry date | Sep 22, 1995 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31928
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
Heat seals of closely controlled peel strengths are obtained utilizing a heat seal layer comprising essentially a blend of an ethylene vinyl acetate copolymer and a high density ethylene homopolymer, wherein a sealing temperature is employed adapted to activate the copolymer to seal, but insufficient to activate the homopolymer. Film packages prepared according to the invention may embody an easy opening peel seal achieved by sealing in the above-defined temperature range, and much stronger seals in other areas of the package achieved using the same heat seal layer, but a higher sealing temperature generally nearer the crystalline melting point of the homopolymer constituent.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.