Patent · US Expired

Method of manufacturing thermoplastic sheet or film

US5149481A · kind A · utility

24Cited by

6References

4Claims

0Family size

Assignee

Rohm GmbH Chemische Fabrik · DE

Inventors

Heinz Gross · Lutherstadt Eisleben, DE
Andreas Fetzer · Emmelshausen, DE
Günther Dickhaut · Riedstadt, DE

Key dates

Filing date	Jun 10, 1991
Grant date	Sep 22, 1992
Priority date	—
Expiry date	Jun 10, 2011

Classification

Technology area (CPC B)Performing Operations; Transporting
CPC primaryB29C59/04
WIPO fieldOther special machines
WIPO sectorMechanical engineering

Abstract

An extruded, smooth finished solid sheet or film of thickness <1 mm is prepared from a thermoplastic plastic having a glass transition temperature >50.degree. C., by extruding the plastic in the thermoplastic state through a slot nozzle to form a flat extruded strip, which is introduced into the roll gap of a roll stack having a smoothed upper roll and a lower roll, with the upper roll being maintained at a temperature below the glass transition temperature of the thermoplastic plastic and with the lower roll being maintained at a temperature in the plastic state domain of the thermoplastic plastic, and, after exiting the roll gap, the extruded strip is moved resting on a smooth-finished endless belt which passes around the lower roll, thereby smoothing the surface of the strip; and cooling said extruded strip below the glass transition temperature.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.