Flexible cellular plastic - with closed cells subjected to compression after expansion

摘要

The closed cells in a flexible expanded plastic are subjected to a temporary compression after a lapse of time beyond that required for maximum expansion, the crushing effect giving rise to liberation of gas from the cells and producing a hollow cellular structure which is elastic. The process yields light cellular, flexible materials at high output and low cost and may be applied to polyurethanes and other expansible materials. The lapse of time before applying pressure is pref. 3-4mins so that pressure is applied before the internal gases have cooled. Pressure is applied by means of compression rolls, beaters, eccentrics, or vibrations. Alternatively compressed gas may be blown into the foam.