Flexible packing laminate in the form of sheets or of a web, a method for the manufacture of the laminate and packing containers manufactured from the laminate
US4994310A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 30, 1988 |
| Grant date | Feb 19, 1991 |
| Priority date | — |
| Expiry date | Nov 30, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31783
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
In the manufacture of packing containers by means of folding of laminate in the form of sheets or of a web of the type which comprises a relatively thick carrier layer (2) of paper or cardboard and a gas-tight, thin metal foil (5) the laminate is subjected to stresses which, particularly within folding regions comprising multiple material thicknesses, may be so strong that crack formations occur in the metal foils protecting against gas which are sensitive to tension, thus entailing the risk of the intended gas barrier characteristics of the packing container being impaired or wholly lost. To counteract this risk the packing laminate is provided with a layer (6) of ethylvinyl alcohol laminated between the metal foil (5) and the carrier layer (2) which for one thing is mechanically sufficiently durable to withstand the external stresses during the folding of the laminate, and for another has sufficiently good gas barrier properties to compensate for the loss in gas tightness which thus may arise if the integrity of the metal foil (5) is lost during the manufacture of the container. Preferably the laminate is provided also with a further layer (7) of a material permeable to moisture …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.