NO743567L

A method of preparing a phenolaldehyde foamed plastic which involves mixing (1) a phenolaldehyde oligomer, such as a resol-type resin, or a mixture of such a resol-type resin with a novolac-type resin, (2) an acidic catalyst, such as an oligomeric product obtained by the treatment of an aromatic sulphoacid with formaldehyde, or an oligomeric product obtained by the treatment of an aromatic sulphoacid with formaldehyde and a nitrogen-containing compound, such as urea, aniline, and 4.4-diaminodiphenolmethane, (3) a compound of a complex-forming metal, such as cobalt, magnesium, manganese, vanadium, chromium, nickel, copper, iron, titanium, and lead, in the form of its oxide, hydroxide, salt, or mixtures thereof, (4) a surfactant, and (5) a foaming agent. The resulting mixture is foamed and cured at a temperature up to 100 DEG C. Introduction of the complex-forming metal insures improved water-resistance of the resulting foamed plastic.