PROCESS AND HIGH-PRESSURE MIXING APPARATUS FOR THE PRODUCTION OF FROTHED POLYURETHANE FOAMS

摘要

A process and a high-pressure mixing apparatus for the production of a frothed polyurethane foam. Two reactive chemical components and a low-boiling blowing agent (CO2) are mixed into a high pressure mixing apparatus comprising a mixing chamber (10) connected to a discharge duct (19); the flow of the mixture is throttled to generate a pressure inside the mixing chamber (10) which is sufficient to maintain the blowing agent at a liquid state. The mixture is thereupon frothed by releasing the blowing agent along a frothing chamber (18) extending between the mixing chamber (10) and the discharge duct (19); a back-pressure is generated into the frothing mixture by extending the frothing chamber (18) for a substantial length and by changing the flow direction of the frothing mixture while flowing from the frothing chamber (18) into the discharge duct (19).