Method of concurrently-biaxially drawing polyvinyl alcohol film
US4230654A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 31, 1979 |
| Grant date | Oct 28, 1980 |
| Priority date | — |
| Expiry date | Jan 31, 1999 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2329/04
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A concurrent-biaxially drawn polyvinyl alcohol film is prepared by fabricating a molten hydrate polyvinyl alcohol into a film; drying it under preventing an orientation thereof to form a substantially non-orientated substrate film having a water content of 3 to 20 wt. %; coating an aqueous dispersion of a macromolecular compound on at least one surface of the substrate film to form a coated film having an average water content of 5 to 30 wt. % with an increased water content of 2 to 10 wt. %; concurrent-biaxially drawing the coated film at an area elongation percent of 600 to 1300% to form a drawn film; drying the drawn film under releasing stress at a water content of less than 3 wt. % to form a dried film; and heat-treating continuously the dried film at higher than 160.degree. C. and lower than a decomposition temperature for a short time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.