Process for making polyester photographic film base and photographic element comprising said base
US6737226B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 24, 2002 |
| Grant date | May 18, 2004 |
| Priority date | — |
| Expiry date | Oct 24, 2022 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31786
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A process for making polyester film base material comprising more than 65 mol % of 1,4-cyclohexanedimethanol (CHDM) of the total glycol component in the polyester material. The film base is prepared by sequentially carrying out the following steps: (a) casting a molten polyester resin in a machine direction onto a casting surface to form a continuous sheet, (b) drafting the sheet by stretching in the machine direction at a stretch ratio of from 2 to 4, and at a temperature ranging from 70° C. to 130° C., (c) tentering the sheet in the transverse direction by stretching at a stretch ratio of from 2 to 4, and at a temperature ranging from 70° C. to 130° C. to obtain a biaxially oriented film, (d) heat-setting the oriented film at an actual temperature of from 160° C. to 200° C., and (e) cooling the heat-set film without substantial detentering to obtain a biaxially oriented, heat-set polyester-based film having a cutting index of 1 to 1.5 and a tensile toughness ranging from 15 to 55 MPa. The invention is also directed towards a silver halide light sensitive photographic element comprising the PET-based film base made by the present process. The photographic f…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.