Method of producing plasticized polyvinyl alcohol and its use for the preparation of starch-based, biodegradable thermoplastic compositions
US5462981A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 25, 1994 |
| Grant date | Oct 31, 1995 |
| Priority date | — |
| Expiry date | Jul 25, 2014 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2329/04
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The method of producing plasticized polyvinyl alcohol by mixing polyvinyl alcohol in the presence of an organic plasticizer and water in a quantity which is insufficient to dissolve the polyvinyl alcohol under normal conditions, includes the steps of: PA0 i) pre-plasticizing the polyvinyl alcohol at a maximum temperature no higher than its softening point so as to produce a pre-plasticized polyvinyl alcohol having a melting point below the softening point of the polyvinyl alcohol used, and PA0 ii) further processing the pre-plasticized polyvinyl alcohol thus produced at a temperature above its melting point, under shear-stress conditions and for a period of time to produce a substantially homogeneous melt.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.