Extrudable polyvinyl alcohol compositions containing modified starches
US5362778A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 16, 1993 |
| Grant date | Nov 8, 1994 |
| Priority date | — |
| Expiry date | Feb 16, 2013 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08L3/04
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
An extrudable polyvinyl alcohol composition useful for packaging and molding applications is prepared by melt blending polyvinyl alcohol and thermoplastic modified starch to provide a product which has reduced water sensitivity, improved modulus and reduced elongation at high relative humidity. A method for extruding the polyvinyl alcohol composition comprises: PA1 adding sufficient energy to the polyvinyl alcohol composition to both melt it and essentially eliminate the polyvinyl alcohol crystallinity in the melt, and PA1 simultaneously removing energy from the melt at a rate sufficient to avoid decomposition of the polyvinyl alcohol. The thermoplastic modified starch may be added to the polyvinyl alcohol before or during the melting of the polyvinyl alcohol and elimination of its crystallinity, or the starch may be blended with the thus treated polyvinyl alcohol and then melt extruding the polyvinyl alcohol/starch blend.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.