Preparation of flexible elastomeric cellular polyurethane products

Claim 1

IN THE PROCESS OF PREPARING A FLEXIBLE ELASTOMERIC CELLULAR MATERIAL FROM THE REACTION OF AN ORGANIC DIISOCYANATE, WATER AND AN ACTIVE-HYDROGEN-CONTAINING POLYMERIC MATERIAL CONTAINING NOT MORE THAN 0.2% WATER BY WEIGHT AND BEING SELECTED FROM THE GROUP CONSISTING OF POLYESTERS, POLYESTERAMIDES AND POLYALKYLENE ETHER GLYCOLS HAVING AN AVERAGE MOLECULAR WEIGHT OF FROM 750 TO 2,250 AND A HYDROXYL NUMBER OF FROM 50 TO 150, SAID POLYESTERS AND POLYESTERAMIDES HAVING AN ACID NUMBER NOT GREATER THAN 5 SAID POLYESTER BEING PREPARED FROM THE CONDENSATION OF AT LEAST ONE DISCARBOXYLIC ACID AND AT LEAST ONE GLYCOL, SAID POLYESTERMIDES BEING PREPARED FROM THE CONDENSATION RECTION OF AT LEAST ONE DICARBOXYLIC ACID, AT LEAST ONE GLYCOL AND A BIFUNCTIONAL AMINO COMPOUND SELECTED FROM THE GROUP CONSISTING OF AMINO CARBOXYLIC ACIDS, AMINO ALCOHOLS AND DIAMINES, WHICH PROCESS INCLUDES THE STEPS OF FIRST FORMING A LIQUID PREPOLYMER BY REACTING SAID POLYMERIC MATERIAL WITH FROM 0.9 TO 1.10 MOLS OF AN ORGANIC DIISOCYANATE PER MOL OF SAID POLYMERIC MATERIAL UNTIL THE EXOTHERMIC HEAT OF REACTION HAS BEEN SUBSTANTIALLY EVOLVED AND REMOVED FROM THE REACTION MIXTURE, AND THEN ADDING ADDITIONAL ORGANIC DIISOCYANATE AND WATER TO SAID LIQUID PREPOLYMER, AND CURING THE COMPLETE REACTION MIXTURE, THE IMPROVEMENT WHICH COMPRISES EMPLOYING IN AT LEAST ONE OF THE DIISOCYANATE REACTIONS A MIXTURE OF TOLYLENE DIISOCYANATES CONTAINING FROM 9 TO 35% BY WEIGHT OF THE 2,6 ISOMER AND FROM 91 TO 65% BY WEIGHT OF THE 2,4 ISOMER.