Patent · US Expired

Method for making biaxially stretched articles of thermoplastic resin

US4235834A · kind A · utility

12Cited by

7References

7Claims

0Family size

Assignee

Rohm Co., Ltd. · JP

Inventors

Heinz Vetter · Weiterstadt, DE
Ernst Friederich · Darmstadt, DE
Karl-Heinz Schanz · Heilbad Heiligenstadt, DE
Hartmut Schikowsky · Darmstadt, DE

Key dates

Filing date	Feb 13, 1978
Grant date	Nov 25, 1980
Priority date	—
Expiry date	Feb 13, 1998

Classification

Technology area (CPC B)Performing Operations; Transporting
CPC primaryB29K2031/00
WIPO fieldOther special machines
WIPO sectorMechanical engineering

Abstract

A method is disclosed for biaxially stretching a band of thermoplastic resin which comprises attenuating a band of unstretched resin, in a forming zone while the resin is in the thermoelastic condition, by passing the band between two surfaces spaced at a distance less than the thickness of said band of unstretched resin while permitting said band to expand in width, and then cooling said band to a temperature below the softening point of the resin while maintaining the dimensions of the attenuated and expanded band; apparatus for performing such a method is also disclosed.

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