| 摘要 |
691,592. Seaming sheet material. STEVENS, A. H. (Shellmar Products Corporation). Dec. 15, 1948. No. 32438/48. Class 42 (i). [Also in Group XXVIII] A method of making flexible tubes of thermoplastic material such as rubber hydrochloride comprises placing a web or webs.of non-thermoplastic material 12, such as paper, adjacent one face of a composite web consisting of two lengths 11 of thermoplastic material of.greater width than the total width of the paper, winding the webs into a roll 13 with the paper web separating successive layers of the composite web, and heating the ends of the roll to unite the contiguous edges of the composite web to form a tube. Heating may be effected by holding against a hot plate, by a flame, or by immersion in molten metal. The seamed tube is unwound and cut into lengths. The edges of one of the webs 11 may be coated with a pigmented lacquer ink to prevent the adjacent layers of the composite web from sticking together at their edges during heating. |
