| 摘要 |
Method of making foam thermoplastics mouldings from pre-expanded thermoplastics, such as polystyrene, consists of using heat and steam to produce further foaming and sintering together of the particles in the mould. Mould surfaces are cooled before the moulding is removed. This (conventional) procedure is amplified by releasing part of the gas and the vapours from the interior of the moulding at the start of cooling thus reducing the pressure by a predetermined amt. Moulding is then allowed to bear again against the internal facings of the mould cavity and is cooled to give it its final form. Used in partic. for mouldings made from expanded polystyrene. Method enables greater control over the expansion pressure to be attained. |
