| 摘要 |
PCT No. PCT/NL92/00040 Sec. 371 Date Aug. 30, 1993 Sec. 102(e) Date Nov. 1, 1993 PCT Filed Feb. 27, 1992 PCT Pub. No. WO92/15638 PCT Pub. Date Sep. 17, 1992.Process and intermediate for preparing an intrinsically foamed thermoplastic polymer comprising a vinyl monomer and maleic acid and/or maleic anhydride, in which process a polymer composition comprising: a) a core polymer based on a.1) 12-50 moles % maleic acid and/or maleic anhydride a.2) a vinyl monomer, and a.3) optionally a third monomer, where the sum total of a1+a2+a3 is 100 moles % and the weight average molecular weight of the core polymer is 50000-500000, and b) optionally a nucleating agent, is introduced into equipment suited for making foam, in which process the core polymer, and optionally the nucleating agent, are brought to a temperature which is high enough to release CO2 from the core polymer, and in which process the polymer melt is expanded to form a polymer foam with the desired density. The core polymer is preferably a polymer of styrene and maleic anhydride.
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