In situ prodn. of phenol-formaldehyde foams - by pouring prefoamed mixt. of resol and heated catalyst, e.g. into cavity walls

摘要

Phenol-formaldehyde foams (e.g. for filling cavity walls of buildings) are produced by introducing a resol and a heated catalyst into a mixer and pouring it in situ. This method gives very little pressure on the walls. Pref. a solid blowing agent is used which reacts with the acid catalyst to give a product which does not condense. The blowing agent pref. acts as a neutraliser and is esp. an alkali(ne earth)carbonate of grain size 1-20 mu. A volatile blowing agent is pref. also used.