Cross-linking blocked two-step prepolymer polyurethane coating compositions

Claim 1

A CURABLE POLYURETHANE COATING COMPOSITION WHICH COMPRISES ON THE BASIS OF 100% BY WEIGHT (A) ABOUT 25% TO 100% OF A MIXTURE COMPRISING (1) A BLOCKED ISOCYANATE-TERMINATED POLYETHERBASED URETHANE INTERMEDIATE WHEREIN SAID POLYETHER HAS A MOLECULAR WEIGHT OF ABOUT 134 TO ABOUT 600, SAID INTERMEDIATE BEING THE PRODUCT OF A PROCESS WHICH COMPRISES: FIRST, MIXING A POLYETHER POLYOL WITH AN ORGANIC DIISOCYANATE IN THE PROPORTION OF ABOUT 2:1 TO 3:2, INCLUSIVE, MOLES OF POLYOL TO DIISOCYANATE AT A TEMPERATURE OF ABOUT 20*C. TO 100*C. UNTIL A HYDROXYTERMINATED ADDUCT HAVING A SUBSTANTIALLY CONSTANT VISCOSITY IS OBTAINED; SECOND, MIXING THE HYDROXY-TERMINATED ADDUCT WITH ABOUT ONE MOLAR PROPORTION OF AN ORGANIC DIISOCYANATE FOR EACH HYDROXY GROUP OF THE SAID ADDUCT AT A TEMPERATURE OF ABOUT 20* TO 70*C. UNTIL AN IXOCYANATE-TERMINATED ADDUCT HAVING A SUBSTANTIALLY CONSTANT VISCOSITY IS OBTAINED; AND THIRD, MIXING THE ISOCYANATE-TERMINATED ADDUCT WITH ABOUT ONE MOLAR PROPORTION OF A BLOCKING AGENT FOR EACH ISOCYANATE GROUP UNTIL A BLOCKED ISOCYANATE-TERMINATED ADDUCT IS OBTAINED, WHEREIN SAID POLYETHER POLYOL IS A MEMBER SELECTED FROM THE GROUP CONSISTING OF (A) POLYPROPYLENE ETHER GLYCOLS HAVING A MOLECULAR WEIGHT BETWEEN ABOUT 134 AND 1000 AND (B) AN ALKYLENE OXIDE ADDITION PRODUCT OF A POLYHYDRIC ALKANOL, SAID ALKANOL HAVING ABOUT THREE TO TEN CARBON ATOMS AND AT LEAST THREE AND NOT MORE THAN SIX HYDROXY GROUPS AND SAID ADDITION PRODUCT HAVING ON AN AVERAGE AT LEAST ONE AND NOT MORE THAN TEN OXYALKYLENE GROUPS HER HYDROXY GROUP, AND WHEREIN EACH OXYALKYLENE GROUP CONTAINS ABOUT TWO OR FOUR CARBON ATOMS, AND SAID BLOCKING AGENT IS A MEMBER SELECTED FROM THE GROUP CONSISTING OF PHENOL, CRESOL, ETHYL ACETYL ACETATE (DIACETIC ESTER), CYCLOHEXANONE OXIME, AND ISOPROPANOL, AND (2) A DEBLOCKING AGENT HAVING TWO TO FOUR HYDROXY GROUPS SELECTED FROM THE GROUP CONSISTING OF (A) HYDROXY-TERMINATED TERTIARY NITROGENCONTAINING POLYETHER-BASED INTERMEDIATES PREPARED BY, FIRST, MIXING A POLYPROPYLENEETHER GLYCOL WITH AN ORGANIC DIISOCYANATE IN THE PROPORTION OF ABOUT 1:2 MOLES OF GLYCOL TO DIISOCYANATE AT A TEMPERATURE OF ABOUT 20*C. TO 70*C. UNTIL AN IXOCYANATE-TERMINATED POLYPROPYLENEETHER ADDUCT IS OBTAINED AND, SECOND, MIXING THE ISOCYANATETERMINATED ADDUCT WITH A HYDROXY TERTIARY AMINE IN THE PROPORTION OF ABOUT 1:2 MOLES OF ADDUCT TO HYDROXY TERTIARY AMINE AT A TEMPERATURE OF ABOUT 20*C. TO 100*C. UNTIL A HYDROXY-TERMINATED ADDUCT IS OBTAINED, WHEREIN SAID POLYPROPYLENEETHER GLYCOL HAS A MOLECULAR WEIGHT BETWEEN ABOUT 134 AND 1000, AND WHEREIN SAID HYDROXY TERTIARY AMINE IS SELECTED FROM THE GROUP CONSISTING OF COMPOUNDS OF THE FORMULAE: