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Abstract

An article of a thermoplastic of polyester or polyamide type, preferably of polyethylene terephthalate, manufactured from an element consisting of an edge part which surrounds a body in an arrangement in which the latter is sunk relative to the edge part. The element is formed from a blank of mainly amorphous material or from a material having a crystallinity of less than 10%. The blank consists, for example, of a flat plate, a blank shell or the like. The body or parts thereof are shaped by stretching the blank until that material flows which is located within the material sections of the blank, which form the edge part in the element, the material stretched up to flowing in the body assuming a crystallinity of between 10% and 25%, while the crystallinity in the material in the edge part and in the unstretched parts retains its original value of less than 10%. At least the body of the element is expanded against warm mould walls until the final shape of the particular article is obtained. Optionally, the expansion is preceded by a number of drawing steps with an axial elongation of the body coupled with a simultaneous reduction in its dimensions at right angles thereto.

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First Claim