General Electric Company

Robert Allan Bourne

Dennis Joseph Coyle

Kenneth L Lilly

William C Paul

Russell Wayne Wildeman

Robert Morrow

Brian Scott Schenk

An apparatus for producing a thermoplastic film having low-birefringent, low stress and at least one polished surface for optical media applications as well as low stress film for non-optical applications using a continuous extrusion process. The apparatus consists of a novel calendering roll in a calendering roll stack wherein, at least one roll consists of an inner steel shell, a resilient covering over the inner steel roll and a multi-layer metal sleeve outer covering of at least two layers. The metal sleeve preferably consists of three layers. The inner layer of the multi-layer outer sleeve is preferably nickel, the intermediate layer is preferably copper and the outer layer is preferably chrome with a highly polished surface. The film produced by the process has a retardation value (birefringence times thickness) of less than about 100 nanometers and a surface roughness of less than about 4 microinches. The process is a continuous extrusion process for producing such film or sheet and does not require any further finishing operations.

Film extrusion process for producing thermoplastic film

An apparatus and method for controlling in a variably controllable fashion the width of an extruder die opening whereby the width of material being extruded may be controllably varied.

Variable width die and method for extruding sheet products

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Mt. Vernon, IN, United States of America

Robert Allan Bourne