| 摘要 |
883,562. Coating tubes &c. REIFENHAUSER, H. Dec. 20, 1957 [Dec. 20, 1956], No. 39682/57. Class 87(2). [Also in Group XXVIII] A method of coating the interior of a board, paper, &c. tube 8 with a thermoplastic material 5 e.g. polyethylene comprises forming a strip 12 of the board &c. into the tube 8 and feeding the tubes over an extrusion nozzle 4 which has a continuous discharge opening 7 through which the plastic material 5 emerges to coat the interior of the tube. The edges 11 of the strip 12 may overlap and have between them a filament of plastic material which under heat and pressure welds the overlapping edges 11 together. The filament may be applied from a roller 14, Fig. 3, heated by a heater 15, Fig. 6 (not shown), and the overlapping edges passed through rollers 16, 17, or the filament may be applied as a "bleed" 23 from the extrusion head, Fig. 7, and the edges 11 be passed through rollers 25, 26. In place of the heater 15 the pressing rollers 16, 17; 25, 26 may be heated. The interior of the coated tube may be filled with liquid, pulverulant a granular material, e.g. foodstuff through the bore 10 of the extrusion head.
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