Water-resistant polyvinyl alcohol film and its application to the preparation of gas-impermeable composite articles
US5030404A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 3, 1990 |
| Grant date | Jul 9, 1991 |
| Priority date | — |
| Expiry date | Jan 3, 2010 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31928
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Polyvinyl alcohol films are provided which are gelled, non-tacky, bubble-free and resistant to water at ambient temperatures. The polyvinyl alcohol film is obtained by plasticizing (fluxing) and melting granules of pure polyvinyl alcohol containing from 25 to 35% by weight of water at a temperature at least 100.degree. C. above the equilibrium melting point of the granules and less than or equal to 220.degree. C., and extruding the melted granules through a die at a temperature at least 5.degree. C. above the equilibrium melting point of the granules and less than or equal to 98.degree. C., optionally followed by monoaxial stretching or biaxial stretching of the unstretched film obtained. The stretched or unstretched film may be heat-treated to improve its properties. The polyvinyl alcohol film can be used to prepare with thermoplastic films composite films or sheets having a high gas impermeability. The invention also provides composite, biaxially oriented, impermeable barrier layer coated, thermoplastic hollow shaped articles useful as packaging materials, e.g., as packages and bottles for flavored foods and carbonated beverages. The hollow shaped articles are produced by externa…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.