| 摘要 |
Moulded plastics articles are made by filling a mixt. of at least two components which react exothermically to form a solid, into a mould of material with softening temp. and time greater than the gelling temp. and time, esp. greater than the hardening temp. and time, of the reaction mixt. The mould material is pref. a thermoplastic (pref. vacuum formed PVC) and the reaction mixt. also contains a filler and opt. a pigment. Used for mfr. of low cost articles, e.g. boundary posts for roads. High costs of presses, injection moulding machines and metal moulds are eliminated, together with maintenance costs. Labour costs are reduced by around 50%, no skilled operators being required. High proportions of cheap, hard mineral fillers can be used. Overall cost of articles is reduced by about 35%. |
