Manufacture of articles by drawing and blow-moulding

A process for the manufacture of an article from polyethylene terephthlate or similar materials comprising providing a substantially flat blank of amorphous, polyethylene terephthlate having a crystallinity of less than 10%, clamping said blank between clamping devices to form at least one inner zone completely surrounded by a closed, band-like, clamped section of material, applying a press element against said inner zone over a region smaller than the total area of said inner zone, whereby a second closed, band-like zone is formed between said clamped band-like section and said inner zone to which the press element is applied, relatively displacing said press element and said clamping devices with the thermoplastic material at a temperature below the glass transition temperature (Tg) while maintaining said press element in contact with said inner zone, the second band-like zone being substantially greater than the thickness of the blank whereby the material in said second band-like zone is freely stretched by drawing in a drawing region between the outer surface of the press element and the inner surface of the clamping devices without contact of the drawn material with the surfaces of the clamping devices, the material in said drawing region forming a transition zone at which flow takes place in the material reducing the original thickness of the blank by a factor of about 3 to effect crystallization thereof and monoaxial orientation whereby a drawn element is formed which comprises an edge part composed of said clamped section and a body which is drawn relative to said edge part and includes material drawn until it flows to form the monoaxially oriented crystallized material, the crystallinity of said material of said body being between 10% and 25%, while the crystallinity of the material in said edge part and in any undrawn part of the body retains its original value of less than 10%, and reshaping said body at a temperature above the glass transition temperature (Tg) by blow-moulding to achieve the shape of the final product.