Polyvinyl alcohol compositions prepared by crosslinking in a freezing step
US5972375A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 23, 1997 |
| Grant date | Oct 26, 1999 |
| Priority date | — |
| Expiry date | Dec 23, 2017 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08L35/08
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The invention provides a translucent, water-insoluble hydrogel composition and methods of making it. The hydrogel composition comprises a polyvinyl alcohol polymer and a complexing agent which are physically crosslinked to form a semi-crystalline polyvinyl alcohol-complexing agent polymer complex. This is achieved by: PA1 (i) combining a polyvinyl alcohol polymer with a suitable aprotic solvent; PA1 (ii) Adding a complexing agent to (i) to form a water soluble complex with the polyvinyl alcohol polymer; and PA1 (iii) Allowing the polyvinyl alcohol polymer and the complexing agent to form a water-insoluble, semi-crystalline structure. The formation of the semi-crystalline structure is assisted by freezing the polyvinyl alcohol/complexing agent/polar aprotic solvent mixture.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.