| 摘要 |
1351931 Extruded packaging foam FREEFLOW PACKAGING CORP 16 Jan 1973 [31 Jan 1972] 2229/73 Heading B5A [Also in Divisions B8 C3 and F2] A free-flow interlocking packing material comprises units 10 of a foamed semi-rigid plastics material in the form of slices cut from a tube 38 having an elongated figure-of-eight section. The units are produced by apparatus in which a liquid or heat-softened plastics mixture is extruded from head 32 from which it is pulled as a foamed plastics tube 38 by friction belts 42. The tube passes through crimping wheels 48, 50 forming the adhered centre section 12, and is sliced by rotaty cutter 46. Progressive expansion of the slices is carried out by a succession of heating and ageing steps. The plastics material is selected from the group of polymers consisting of alkenyl aromatic, aliphatic olefin, and polyurethane polymers. |
