| 摘要 |
1,252,522. Expanded polybutylene articles. BADISCHE ANILIN- & SODA-FABRIK A.G. 26 March, 1969 [27 March, 1968], No. 15712/69. Heading B5A. Expanded polybutylene articles are produced by heating and compressing expanded particles of polybutylene or butylene copolymers until fused in a confined space, e.g. a closed mould, from which gaseous or liquid substances can escape but not the expanded particles. Heating medium can be passed through the confined space e.g. through at least one probe or perforated tube, which is withdrawn before fusing and compression of the particles. The particles, which are preferably closed-cell, may be compressed from two directions toward the centre of the mould e.g. by 5-60% of their original bulk volume. The heating medium is preferably recycled. Hot steam may be used as the heating medium but heating may also be effected with infra-red radiation or by blowing in hot air. The particles may be coated with a small amount of a substance having a high dielectric loss, e.g. water, aqueous salt solutions and heated in a high frequency field. Copolymers of butylene, e.g. with isobutylene, ethylene, may also be used. |
