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Abstract

Biaxially oriented tubular articles which are destined to provide bodies for processable food containers are made from an elongate tube of thermoplastics material as it emerges from an extruder. The manufacturing process comprises repeatedly performing a cycle of operations each including the following steps: engaging the tube by a first clamping means (11,12) over a first region at a leading end of the tube (10) and by a second clamping means (13,14) over a second region at a spacing from the first region, so as to define between the clamping regions a portion of the tube to be longitudinally stretched and radially expanded; moving the clamping means apart to stretch the tube portion longitudinally and admitting pressure fluid to the tube portion to expand it radially, such stretching and expansion forming a bubble (100) of biaxially oriented thermoplastics material adjacent the leading end of the tube; and severing (at 22) at least a substantial part of the bubble from the tube to form the tube with a new end as the said leading end of the tube for the succeeding cycle of operations.

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First Claim