Process for making thick-skinned articles comprising polyurethane foam

Claim 1

A PROCESS FOR MAKING AN ARTICLE COMPRISING POLYURETHANE FOAM WHICH COMPRISES: (A) BLENDING A POLYURETHANE MIXTURE HAVING AN ULTIMATE FREE BLOW DENSITY FROM ABOUT 2 TO 8 POUNDS PER CUBIC FOOT, SAID MIXTURE BEING CAPABLE OF SUBSEQUENTLY FOAMING INTO A FINAL POROUS STRUCTURE, SAID MIXTURE COMPRISING A POLYISOCYANATE, AN ACTIVE HYDROGEN-CONTAINING ORGANIC SUBSTANCE CAPABLE OF FORMING A POLYURETHANE STRUCTURE WITH SAID POLYISOCYANATE, AND A BLOWING AGENT; (B) CHARGING A FIXED VOLUME MOLD CAVITY WITH A QUANTITY OF SAID MIXTURE IN EXCESS OF THAT NORMALLY ADEQUATE TO FILL THE WHOLE MOLD CAVITY WITH FOAM GENERATED AGAINST ATMOSPHERIC PRESSURE, SAID QUANTITY CHARGED BEING SUFFICIENT FOR EXERTING AN AUTOGENOUS PEAK PRESSURE OF ABOUT 8-35 P.S.I.G. IN THE MOLD CAVITY DURING SUBSEQUENT FOAMING OF SAID MIXTURE; (C) CLOSING THE MOLD CAVITY; (D) PERMITTING SAID MIXTURE THERIN TO FOAM UNTIL MOVEMENT OF THE FOAM SUBSIDES WHILE BLEEDING OFF FLUID FROM THE MOLD CAVITY THAT IS IN EXCESS OF THAT REQUIRED FOR ATTAINING SAID PEAK POSITIVE PRESSURE; (E) DISENGAGING THE RESULTING ARTICLE FROM SAID MOLD CAVITY.