Method and apparatus for uniformly stretching thermoplastic film and products produced thereby
AssigneeClopay Plastic Products Company, Inc.
InventorsLeopoldo V. Cancio, Thomas G. Mushaben, Robert M. Mortellite, Pai-Chuan Wu
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Abstract
Thermoplastic films and laminates are made by extrusion and stretching using differential speed rollers employing a short stretching gap of no more than one inch immediately after the extruded film product is formed. The method and apparatus control the thickness of the stretched film and impart desirable mechanical properties thereto such as film products with a high modulus for handling and suitable tensile for softness.
Claims16
An apparatus for making a stretched thermoplastic film comprising an extruder for extruding a thermoplastic molten extrudate in the form of a web,
- a chill roller for operating at a peripheral velocity (V1) and at a temperature (T1) to receive and cool said web thereby forming a film,
- a second roller for operating at a peripheral velocity (V2) greater than said V1 to receive said film at a temperature (T2),
- said second roller spaced from said chill roller to provide a roll gap of no more than one inch between said chill roller and said second roller for stretching said film to provide a film of uniform gauge.
Dependencies are inferred from the claim text.