Composite polyester/PVA barrier films
US5773092A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 7, 1997 |
| Grant date | Jun 30, 1998 |
| Priority date | — |
| Expiry date | May 7, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31797
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Polyester-based, biaxially oriented composite films having good transparency and gas-barrier properties, exhibiting excellent resistance to mechanical shock and being easily recyclable, comprise a polyester base film (for example shaped from polyethylene terephthalate) 5 .mu.m to 50 .mu.m in thickness, coated on at least one of its two face surfaces with a layer of polyvinyl alcohol having a number-average degree of polymerization equal to or greater than 350 and a thickness less than or equal to 0.3 .mu.m, the mean roughness Rz of the base film being less than or equal to 0.30 .mu.m on the at least one face surface of the film onto which a polyvinyl alcohol layer is coated and said at least one coated face surface comprising, on average, not more than 20 peaks of a height equal to or greater than 1 micrometer and not more than 150 peaks of a height ranging from 0.4 to 1 micrometer, per square millimeter, and such composite films exhibiting a permeability to oxygen, measured at 23.degree. C. at 50% relative humidity, less than or equal to 3 cm.sup.3 /m.sup.2 /24 h.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.