Process for controlling the curl of photographic film

US4994214A · kind A · utility

Assignee

• Agfa-Gevaert NV · BE

Inventors

• Marc P. Stevens · Belsele, BE
• Gery Vancoppenolle · Weerde, BE

Key dates

• Filing date: Jun 29, 1989
• Grant date: Feb 19, 1991
• Expiry date: Jun 29, 2009

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B29K2105/256
• WIPO field: Other special machines
• WIPO sector: Mechanical engineering

Abstract

A process of making biaxially oriented polyethylene terephthalate photographic film having a controlled amount of curl in the longitudinal direction, wherein the file is subjected to longitudinal stretching while being asymmetrically heated across its thickness, then wound into a stock roll, and the stock roll thus obtained is heat-tempered. The stock roll after heat-tempering may be longitudinally slit, cut and rewound into smaller rolls in a winding direction opposite to the direction of the longitudinal curl induced in the film during the longitudinal asymmetrical heat-stretching.