Prepn of hard moulded articles in polyurethane foam

摘要

Prepn of hard moulded articles in polyurethane foam.. F1-. Having a total density of 0.15 to 0.04 g./cm3 by mixing polyisocyanates with compds. contg. active H-atoms and introducing this mixt. into a moulding apparatus together with at least 70% wt. of the blowing agents which normally low boiling solvents. The main advantages of the polyurethane foams of this invention are that they have a very dense strong surface skin but the interior foam is of low density. These foams are particularly useful as insulating materials used in the construction of refrigerators.