Process for making a cellulose triacetate photographic film base
US5686036A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 11, 1996 |
| Grant date | Nov 11, 1997 |
| Priority date | — |
| Expiry date | Jan 11, 2016 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29K2001/00
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
The invention provides a method of making a cellulose triacetate photographic film base which comprises providing a casting composition of cellulose triacetate, plasticizer, and solvent having a cellulose triacetate and plasticizer concentration of from 36% to 72% by weight, casting the coating composition at a temperature of from 40.degree. C. to 63.degree. C. unto a surface maintained at from -70.degree. C. to 21.degree. C. for a residence time from 3 to 8 seconds, in accordance with the equation Tr/Tg<1.9, where Tg and Tr are the glass transition temperature in degrees Kelvin and the temperature of the casting composition in degrees Kelvin at a point adjacent to the surface where the film base is separated from the surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.