Hoechst Aktiengesellschaft

Detlef Gneuss

Hans Strutzel

Ludwig Klenk

Wolfgang Meintzschel

This invention relates to a biaxially stretched and longitudinally afterstretched thin-walled tubular film of polyethylene terephthalate having a tensile stress of 40 to 60 kg/mm.sup.2 and a tear resistance of 40 to 70 kg/mm.sup.2 in the longitudinal direction, and an elongation at break of 350 to 800% in the transverse direction. The invention also relates to a process for the production of the film.

Tubular film of polyethylene terephthalate and process for the

This invention relates to a process for the manufacture of a plastic tube suitable for use as a sausage casing, which comprises extruding a crystalline thermoplastic material at a temperature above its crystalline melting point through an annular die of non-uniform cross-section, to produce a tube any cross-section of which varies continuously from a maximum to a minimum, the positions of the minimum and maximum thickness being diametrically opposed, the maximum being 1.3 to 3.0 times as thick as the minimum, cooling the tube to below its crystalline melting point, biaxially orienting the tube, and longitudinally stretching the biaxially oriented tube under conditions such that the temperature of the portion of the tube of maximum thickness is greater than that of the portion of the tube of minimum thickness. The invention also relates to the tube so produced.

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Marktredwitz, Germany

Detlef Gneuss