A method for manufacturing bags or like containers of thermoplastic material

961,202. Making bags; seaming non- metallic sheet material. CELLOPLAST A.B. Nov. 3, 1960 [Nov. 4, 1959], No. 37882/60. Headings B5D and B5K. [Also in Division B8] Bags are formed by piling tubes of thermoplastic foil or pairs of foil sheets, alternate tubes or sheet pairs being of the same material and the intervening ones of a different material, so that when they are cut into lengths and sealed those adjacent one another adhere slightly to form a pack but do not fuse together. The two materials may be polyethylene and polyvinylchloride. The tubes may be sealed at intervals and then cut at each seal to form bags. Where foil sheets are used, their longitudinal edges are sealed first. The tubes may be wound on a drum, the roll of tubing cut radially, removed from the drum and opened out, the tubes being later cut and sealed by a hot wire or knife. Alternatively, the roll may be cut through and the exposed edges later sealed by a hot object either pressed on or held close to them. A hot gas or hot liquid may be used for sealing.