Abstract: A food container comprising an open-ended cylindrical body which is made of a crystallizable polyethylene terephthalate material, and end closures at each end of the body forming with the body a closed container, the body material being biaxially oriented and the container body having been head-set, while restrained against radial or axial shrinkage, at a temperature between about 180.degree. C. and about 240.degree. C., whereby the container is able to withstand hot-filling, pasteurization or sterilization temperatures of up to about 120.degree. C. without undergoing shrinkage of its linear dimensions by more than 3%.

Abstract: A tubular article with a closed end is formed from a thermoformable polymer material, e.g. a high molecular weight saturated linear polyester such as polyethylene terephthalate, by forcing a punch (21) through the plane of a pre-heated and clamped sheet (13) of the polymer, centrally within an annular die (10) so as to draw the sheet into tubular form without exerting compressive stresses on the sheet between the punch and die, the punch being maintained at a temperature below the glass transition temperature of the polymer, e.g. by passing cooling fluid through internal passages (16), and being moved at a speed of at least 1/2 meter per second to effect the drawing. The punch head (21) may be convex or concave to produce a shaped closed end on the article, e.g. for making a pressure-resistant container, and the punch may co-operate with a shaped movable anvil (201) at the end or at an intermediate point in its stroke.

Abstract: For heat-setting tubular articles (such as can bodies) of an at least partly biaxially oriented crystallizable polymer, preferably a saturated linear polyester such as polyethylene terephthalate, e.g. for thermally processable food containers, a tube of the polymer is fitted over a mandrel and clamped at its ends to the mandrel at a temperature below the glass transition temperature of the polymer. The tube is then heated, e.g. by inserting a heater 28 into the interior of the mandrel, above the temperature to which it is to be heat-set (at least 60.degree. C. above for PET) whereupon it shrinks into contact with the mandrel but is restrained from axial or further radial shrinkage. The tube and mandrel are cooled to below the heat-set temperature and the tube may then be cut into can body sections by knives engaging in circumferential grooves. Contact between the tube and mandrel is released, e.g.

Abstract: A method and apparatus are described for flanging a tubular article of a crystallizable thermoplastic polymer, particularly of a saturated linear polyester material such as polyethylene terephthalate, which has been heat-set to an elevated temperature, e.g. for producing bodies for processable food and beverage containers. The open end of the tubular body is applied to a flanging die and heated to a flanging temperature above the glass transition temperature but below the heat-set temperature of the polymer. The tubular body and the die are forced together so that the softened end of the tubular article is forced to move outwards until it abuts against a stop ring to form the flange. The residual shrinkage in the polymer material helps it to take up the precise contours of the die and to form a well-defined flange. The flanged end is then cooled, preferably to a temperature at least 20.degree. C. below the flanging temperature, before releasing the tubular body 10 from the die.

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.

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.