Tris-tetrazoles as chemical blowing agents

摘要

Tris-tetrazoles of formula I, <IMAGE> (I) wherein A is alkylene and R is hydrogen, alkyl or phenyl, are suitable blowing agents for thermoplastic resins, especially for polycarbonates and aromatic polyethers. The foaming process can be carried out at a temperature range of 230 DEG to 300 DEG C., the resulting foamed articles have a fine and homogeneous cellular structure.