| 摘要 |
<p>984,915. Blow-moulding processes. IMPERIAL CHEMICAL INDUSTRIES Ltd. Sept. 16, 1963 [Oct. 18, 1962], No. 39477/62. Heading B5A. In a blow-moulding process for shaped articles, organic thermoplastic material is extruded from a helical die extrusion head 21 comprising a barrel 10 containing a tapering core member 11 having a helical groove 17 therein the depth of which decreases to zero as the core tapers, through a tube forming die, the tube thus formed being enclosed in a mould 28 and expanded by fluid pressure to conform to the shape of the mould. The use of the helical extrusion head prevents join lines in the finished article. Materials used in the process are e.g. polyolefine, polypropylene and poly-4-methyl-pentane-1. Specification 823,066 is referred to.</p> |
