| 摘要 |
1,126,473. Tubular wrappers. RHEINISCHE BLATTMETALL A.G. and M. VONCLAVEBOUHABEN. 9 Feb., 1966 [12 Feb., 1965], No. 5740/66. Heading F2P. [Also in Division B5] In a method of making a tubular wrapper, such as a sausage casing, from a metal (e.g. aluminium) foil coated on one or both sides with a thermoplastic, the tubular wrapper is formed either by longitudinally lapping two edges one over the other, Figs. 2 or 3 (not shown), or by placing the inside of one edge longitudinally against the inside of the other edge and hotwelding the seam such that the width of the seam proper as determined by the width of the jaw of a seaming tool is narrower than the width of contact or overlap of the two edges, thus giving rise to narrow fusion zones 7 alongside the seam-proper. The partly fused zones of the stretched or unstretched plasticscoated metal foil are pressed together by manner of feeding foil past the seaming tool or by cooled or uncooled pressing tools. The method of welding of the seam proper may comprise thermal contact welding, impulse welding, inductive high frequency welding or capacitive high frequency welding. If the last-mentioned method is employed, the foil edge nearest the jaw of the welding tool contains no metal. If thermo-plastics coatings are provided on both sides of the metal foil, the thermoplastic coatings may be the same or different. After the tubular wrapper is filled, the ends may be closed by clips or by twisting or pressing the ends together. |
