Recovery of silver and other valuable constituents from polyester based photographic film
US4078916A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 5, 1977 |
| Grant date | Mar 14, 1978 |
| Priority date | — |
| Expiry date | Apr 5, 1997 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02W30/62
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Scrap photographic film comprising at least a four component system involving a polyalkyleneterephthalate film base, an adhesive or subbing layer utilizing a terpolymer consisting chiefly of polyvinylidenechloride and a gelatin layer containing metallic silver or a compound thereof and a variety of contaminants such as causal dirt, dyes and the like is broken down for recovery of the valuable constituents therein including the silver, the polyvinylidenechloride terpolymer, and the polyesters by treating the chopped photographic film at an elevated temperature with a solvent for both the polyester and polyvinylidenechloride values in which solvent both the gelatin and silver values are insoluble, under conditions chosen to insure the quantitative recovery of the silver values.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.