| abstract |
A process for producing a foamed polymer comprises the steps of: mixing, in a dissolver, a mixture constituted by at least one isocyanate and a first unsaturated anhydride, adding to the mixture, a second aromatic anhydride, at least one foaming agent, a vinylidene compound, poly(vinyl chloride) and a heat stabilizer; until a paste is obtained curing said paste at atmospheric pressure, and at a temperature not higher than 80 DEG C; completing the curing of the paste-like mixture under pressure, by increasing temperature up to 180 DEG C and subsequent cooling, until partially foamed germs are obtained; and completing the germ foaming process, by heating. |