Process for the manufacture of heat resistant multicellular materials

Abstract

Multicellular materials having excellent heat-resistance are provided by preparing granules of 1. a prepolymer obtained from: A. a product containing an imide group, which is A. a bis-imide of the formula: ##STR1## in which D represents a radical of the formula: ##STR2## WHEREIN Y represents H, CH.sub.3 or Cl, m is 0 or 1, and A represents a divalent organic radical containing 2 to 30 carbon atoms, or B. a mixture comprising a bis-imide of formula (I) and a mono-imide of the formula: ##STR3## in which D is as defined above and R represents a hydrogen atom or a monovalent organic radical containing 1 to 20 carbon atoms, and B. an amine product which is A. one or more polyamines containing from 2 to 5 primary or secondary amino groups, at least one of these groups being primary, or B. a mixture comprising one or more polyamines as defined under a) and one or more primary and/or secondary monoamines and/or one or more secondary polyamines, 2. a pore-forming agent and 3. a cell-forming agent, the degree of expansion (as hereinbefore defined) of which is a maximum of 90%, placing these granules in a mould, and effecting complete expansion and thermo-setting of the polymer by heating.

Dependencies are inferred from the claim text.