| 摘要 |
1,248,314. Moulding plastics materials. BADISCHE ANILIN- & SODA-FABRIK A.G. 20 Feb., 1969 [21 Feb., 1968], No. 9152/69. Heading B5A. [Also in Division C3] A process for the production of an expanded plastics moulding wherein particles of a partially crystalline ethylene polymer, which polymer contains an expanding agent capable of causing expansion of the plastics particles at temperatures above its activation temperature and which polymer has been subjected to high energy radiation so as to produce a gel content (as defined) from 5 to 80% by weight, are heated in a mould which is not gastight when closed to a temperature above the crystallite melting point of the polymer and above the activation temperature of the expanding agent. The walls of the mould may be rigidly connected to one another and may be provided with perforations permitting the entry and escape of gaseous or liquid materials without permitting the escape of the polymer particles. The mould may also comprise continuous shaping equipment of a type known for use in the continuous production of mouldings from particulate expanded plastics. The cavity of the mould may be filled with expandable particles to the extent of from 10 to 80% of its volume. |
