Foaming high melting synthetic resin - with chemically stable zinc peroxide blowing agent

摘要

High-melting synthetic resins, e.g. melting above 160 degrees C are foamed by incorporating, as blowing agent, >=1 Zn peroxide having formula Zn1Om.(H2O)n/2 (I) (where 1 = 1-10; m = 2-20; n = 0-5). (I) are esp. ZnO2, Zn2O3 or Zn3O5, and pref. have decomposition temp. 200-260 (220-240) degrees C. Proportion of (I) is esp. 1-30 wt.% w.r.t. resin. (I) are chemically stable. E.g. heat decompsn. of (I) contg. 58.4% ZnO2 is 0.68% after 240 hrs. at 90 degrees C. (I) decompose quickly to form a tiny uniform cell-contg. structure; leave no residue after decomposition and do not cause discolouration.