| 摘要 |
<p>1328872 Moulding thermoplastic materials SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ BV 9 Sept 1970 [11 Sept 1969] 43160/70 Addition to 1166381 Heading B5A A method of forming a thermoplastic article comprises placing a predetermined amount of a molten thermoplastic polymer M, e.g. polypropylene into a mould cavity defined by a rigid surface 10 and a surface 17 of a body 14A which deforms under moulding pressure and has vents 20, closing the cavity by forcing down a second rigid surface 12 into contact with the polymer and the body 14A while permitting trapped air to escape through the vents, maintaining any unsolidified polymer in the cavity under compression until it is solidified by cooling at least one of the rigid surfaces, and removing the solidified article. The body 14A may comprise an elastomeric ring having a concave inner wall and surrounded by a rigid ring 15 adjacent a shim 16. Alternatively it may comprise a circular inflated rubber tube. A predetermined quantity of polymer may be fed to the mould cavity from a weigning table supplied from an extruder.</p> |
