Polyimide film and preparation process of the film
US5260407A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 9, 1990 |
| Grant date | Nov 9, 1993 |
| Priority date | — |
| Expiry date | Jul 9, 2010 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31721
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A polyimide film essentially consisting of polyimide having recurring units of the formula (I): ##STR1## which has a density of 1.335 to 1.390 g/cm.sup.3 at 23.degree. C. and/or a refractive index of 1.605 to 1.680 at 23.degree. C. in the direction of thickness and is transparent; and a preparation process of the polyimide film by extruding the polyimide having recurring units of the above formula (I) through a common melt-extrusion process, casting in a chill-roller to obtain an unstretched film, uniaxially or biaxially stretching the unstretched film to cause molecular orientation, and successively setting the stretched film through heat-treatment.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.