Foaming composition and method for producing foamed polymers.

摘要

A method of making a foamed polymer article by injection molding, using a foaming composition that evolves minimal water and does not form by-products which could pit or chalk the polymer surface. The foaming composition contains an alkali metal borohydride in an amount from 0.01 to 5.0 weight percent of the polymer to be foamed, and sodium dihydrogen phosphate or a polyhydric alcohol such as six-carbon mannitol as an activator to react with the borohydride and produce hydrogen gas. Boric acid can be included with the alcohol. The borohydride is kept separated from the other reactive components such as by encapsulation until gas production is desired when the polymer is heated and molded.