Process for producing microporous coatings and films

Claim 1

THE PROCESS OF PRODUCING A MICROPOROUS POLYMERIC LEATHERLIKE MATERIAL SUITABLE FOR USE IN FABRICATING SHOE UPPERS COMPRISING: (A) FORMING A SOLUTION CONTAINING ABOUT 25% BY WEIGHT OF A THERMOPLASTIC ESSENTIALLY LINEAR POLYESTEURETHANE DISSOLVED IN TETRAHYDROFURAN, SAID POLYURETHANE BEING THE REACTION PRODUCT OF (1) ONE MOL OF AN ESSENTIALLY LINEAR HYDROXYL TERMINATED POLYESTER OF A SATURATED ALIPHATIC GLYCOL HAVING FROM 4 TO 10 CARBON ATOMS AND HAVING HYDROXYL GROUPS ON ITS TERMINAL CARBON ATOMS, AND A MATERIAL SELECTED FROM THE GROUP CONSISTING OF A DICARBOXYLIC ACID OF THE FORMULA HOOC-R-COOH WHERE R IS A AN ALKYLENE RADICAL CONTAINING FROM 2 TO 8 CARBON ATOMS AND ITS ANHYDRIDE, SAID POLYESTER HAVING AN AVERAGE MOLECULAR WEIGHT BETWEEN 600 AND 1200 AND HAVING AN ACID NUMBER LESS THAN 10, AND (2) FROM ABOUT 1.1 TO 3.1 MOLS OF A DIPHENYL DIISOCYANATE HAVING AN ISOCYANATE GROUP ON EACH PHENYL NUCLEUS AND (3) FROM ABOUT 0.1 TO 2.1 MOLS OF A SATURATED ALIPHATIC GLYCOL CONTAINING FROM 4 TO 10 CARBON ATOMS AND HAVING HYDROXYL GROUPS ON ITS TERMINAL CARBON ATOMS, THE MOLAR AMOUNT OF SAID POLYESTER AND SAID FREE GLYCOL COMBINED BEING ESSENTIALLY EQUIVALENT TO THE MOLAR AMOUNT OF SAID DIPHENYL DIISOCYANATE; (B) ADMIXING WITH SAID SOLUTION FROM 100 TO 300 PARTS BY WEIGHT, PER 100 PARTS BY WEIGHT OF THE POLYESTERURETHANE PRESENT THEREIN, OF A SOLID MATERIAL DECOMPOSABLE SOLELY TO AMMONIA, HYDROGEN AND CARBON DIOXIDE GASES, SAID SOLID MATERIAL BEING SELECTED FROM THE CLASS CONSISTING OF AMMONIUM CARBONATE AND AMMONIUM BICARBONATE AND BEING IN PARTICULATE FORM AT LEAST FINE ENOUGH FOR ALL PARTICLES TO PASS THROUGH A 270 MESH SCREEN; (C) SPREADING THE ADMIXTURE OF SAID POLYESTERURETHANE AND SAID DECOMPOSABLE MATERIAL CONTAINED IN SAID SOLUTION INTO FILM OF 4 TO 15 MILS THICKNESS ON TO A NON-WOVEN FABRIC BACKER, SAID FILM BEING CONTINUOUS AND NON-POROUS AS VIEWED UNDER A MICCOSCOPE AT 30X MAGNIFICATION, AND (D) EXPOSING SAID NON-WOVEN FABRIC BAKCER WITH SAID FILM THEREON TO CONDITIONS WHICH DECOMPOSE SAID DECOMPOSABLE MATERIAL INTO AMMONIA, HYDROGEN AND CARBON DIOXIDE GASES BUT AT A TEMPERATURE BELOW 130*C. UNTIL EVOLUTION OF AMMONIA GAS FROM SAID FILM CEASES, THEREBY TO PRODUCE MICROPOROSITY IN SAID FILM AS A RESULT OF GAS EVOLUTION WITHOUT CHANGING THE SURFACE OF SAID FILM AS WHEN VIEWED AT 30X MAGNIFICATION.