Blowing agents and their use in preparations of polyester foams

摘要: Quaternary ammonium borohydrides of the formula ##STR1## wherein R1, R2 and R3 may be same or different each is selected from alkyl, alkenyl, cycloalkyl, aryl, alkaryl aralkyl groups R4 alkyl alkenyl having 1 to 30 carbon atoms, with proviso that R2, are not all benzyl when remainder methyl ethyl. The new prepared by either mixing a borohydride salt quaternary in alkaline aqueous solution extracting resulting amine an organic solvent reacting finely divided salt. compounds used for foaming polyester resins.