Formo-phenolic foams and their process of preparation

Abstract From the Canadian patent

A process for the production of a phenol-formaldehyde foam includes reacting phenol with formaldehyde in the presence of an alkali, removing or neutralizing the alkali and con-, centrating the resulting resol to form a product having a dry extract content of at least 85% and a viscosity at 20°C between 10,000 and 100,000 poises. The product is then mixed at a temperature in the range of from about 50°C to about 70°C with a blowing agent and a low activity acid catalyst the catalyst, being phosphoric acid, the acid sulphate of triethylene glycol or oxalic acid, and the mixture is expanded and hardened at a temperature in the range of from about 80°C to about 100°C.