Method of making laminated polyurethane structures

Claim 1

A CONTINUOUS PROCESS FOR PREPARING A RIGID, MECHANICALLY STRONG, LIGHTWEIGHT LAMINATE STRUCTURE WHICH COMPRISES THE STEPS; (1) DELIVERING A FOAMED URETHANE POLYMER COMPOSITION, CONTAINING A GAS FORMING AGENT, FROM A REACTANT MIXER UNDER PRESSURE THROUGH AN ORIFICE AND BETWEEN A CONTINUOUSLY ADVANCING PAIR OF COVERING SHEETS EACH SUPPORTED BY A TEMPERATURE CONTROLLED ROLL TO ADHERE SAID SHEETS TO THE FOAMED URETHANE POLYMER, (2) POST EXPANDING THE FOAMED URETHANE POLYMER COMPOSITION AND THE COVERING SHEETS BY APPLYING HEAT TO SAID COMPOSITION AND SHEETS TO CONVERT A SECONDARY GAS FORMING AGENT TO A GASEOUS STTE, (3) CUTTING THE CONTINUOUS ASSEMBLY OF THE FOAMED URETHANE POLYMER COMPOSITION AND THE COVERING SHEETS INTO A PLURALITY OF NARROWER ASSEMBLIES OF SUBSTANTIALLY EQUAL WIDTH, (4) TURNING EACH OF SAID NARROWER ASSEMBLIES THROUGH AN ANGLE OF 90 DEGREES, (5) PRESSING SAID NARROWER ASSEMBLIES INTO TOUCHING RELATIONSHIP, (6) ADHESIVELY JOINING SAID NARROWER ASSEMBLIES TO FORM A CORE OF A FOAMED URETHANE POLYMER THAT IS REINFORCED WITH A PLURALITY OF SUBSTANTIALLY EQUIDISTANT PARALLEL REINFORCING SHEETS WHICH RUN THROUGHOUT THE LENGTH OF THE SHEET, AND (7) LAMINATING COVERING SHEETS TO THE TOP AND BOTTOM SURFACES OF THEIR REINFORCED FOAMED URETHANE POLYMER CORE.