| 摘要 |
1312486 Moulding cellular articles FREEFLOW PACKAGING CORP 8 April 1970 [11 April 1969] 16617/70 Heading B5A [Also in Divisions B8 and C3] An interlocking free flow packing material is made by heating a plastics material together with foaming and nucleating agents to form a heat softened extrusion mass which is extruded, e.g. by being continuously fed to an extrusion zone and heating the extrusion mass, to form the heat-softened tube, the tube is subject to cooling, e.g. in an ambient atmosphere, to a hardened stage, the extruded tube is then longitudinally stretched, e.g. by being continuously frictionally engaged to pull the same away from the extrusion zone to thereby stretch and to maintain the freshly extruded material in a desired hollow tube configuration, such longitudinal stretching serving to longitudinally orient gas cells formed in the walls of the tube during the extruding, the hardened tube is continuously sliced to form at least two adjacent substantially hollow annular tube portions, desired lengths of said sliced tube are continuously severed as short hollow sliced sections, and thereafter the severed hollow sections are further heated to expand the longitudinally oriented cells to effect an expansion of the severed sections. The foamed material may be made in an apparatus shown in Fig. 17 wherein extruder 50 with head 52 forms an expanded tube 58 which is pulled by belts 62 into cutter 66 (shown in detail in Figs. 6-16, 26 and 27, in the form of embodiments for producing differently shaped foamed materials) wherein the tube is both sliced and severed and the severed units are held on belt 140 and then passed to expander 144, held on belt 150 and expanded again in 154. The packing elements may be made in the apparatus of Fig. 17 (not shown) wherein extruded tube is stretched, sliced and severed and then expanded in two stages. The use of mating mould units to produce the packing elements is suggested.
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