Froth system for continuous manufacture of polyurethane foam slab-stocks

Abstract

A process and a system for the continuous manufacture of polymeric foams. Reactive chemical components and additives comprising a low boiling blowing agent are mixed under pressure; the mixture is then frothed before chemical reaction takes place by feeding the mixture through a pressure equalizing and frothing device having a pressure-drop zone opening into a frothing cavity having an output aperture to discharge the froth onto a moving substrate.

What is claimed is:  
     
       1. A frothing device for use with a mixture of reactive polymeric polyurethane chemicals and liquid CO 2  blowing agent, comprising a pressure equalizing chamber having a pressurized inlet and a pressure drop outlet elongated in the direction of flow, said pressure drop outlet being dimensioned to maintain back pressure oil  on the upstream mixture to keep the blowing agent  mixture in a liquid state and to initiate frothing under pressure controlled conditions to avoid turbulent evaporation of the blowing agent upon discharge of the mixture from the pressure drop outlet, a walled frothing cavity extending from said pressure drop outlet and positioned so as to intercept the flow from said pressure drop outlet and control the gradual release of gaseous blowing agent into, and to distribute energy within frothing material flowing within said frothing cavity.