Hoechst Celanese Corporation

Gregory W Farell

Stephen J Gust

Marshall Dean Ledbetter

A thin, biaxially oriented polyester film which is asymetrically oriented by stretching 1-2 times in the machine direction and about 3-5 times in the transverse direction in the plane of the film is disclosed. The film has a birefringence of at least 0.085, an optical retardation of at least 9000 nanometers and a shrinkage of less than 2% in any direction at 150.degree. C. The film produced is substantially free of color fringes when viewed in partially polarized light. There are also disclosed two processes for the production of said film.

Growing community of inventors

Greenville, SC, United States of America

Gregory W Farell