Polyoxazoline-Containing Compositions Catalyzed with Onium Salt

Abstract

Polyoxazoline-containing compositions cured in the presence of an onium salt catalyst are disclosed.

1 . A composition comprising:
 (a) a polymer comprising acid functionality,   (b) a polyoxazoline, and   (c) an onium salt group-containing catalyst.   
     
     
         2 . The composition of  claim 1  in which the polymer comprising acid functionality comprises a polyester. 
     
     
         3 . The composition of  claim 1  in which the polymer comprising acid functionality has an acid value of at least 30. 
     
     
         4 . The composition of  claim 1  in which the polyoxazoline comprises a tris-oxazoline. 
     
     
         5 . The composition of  claim 1  in which the onium salt group-containing catalyst comprises a phosphonium salt group-containing catalyst. 
     
     
         6 . The composition of  claim 1  in which (a) is present in amounts of 60 to 95 percent by weight; (b) is present in amounts of 2 to 30 percent by weight and (c) is present in amounts of 0.1 to 10 percent by weight; the percentages are by weight based on total weight of (a), (b) and (c). 
     
     
         7 . The composition of  claim 1 , which is a thermosetting composition. 
     
     
         8 . A thermosetting powder coating composition comprising:
 (a) a polymer comprising acid functionality,   (b) a polyoxazoline, and   (c) an onium salt group-containing catalyst.   
     
     
         9 . The thermosetting composition of  claim 8  in which the carboxylic acid functional polymer is a polyester. 
     
     
         10 . The thermosetting composition of  claim 8  in which the polymer comprising acid functionality has an acid value of at least 30. 
     
     
         11 . The thermosetting composition of  claim 8  in which the polyoxazoline comprises a tris-oxazoline. 
     
     
         12 . The thermosetting composition of  claim 8  in which the onium salt group-containing catalyst comprises a phosphonium salt group-containing catalyst. 
     
     
         13 . The thermosetting composition of  claim 8  in which (a) is present in amounts of 60 to 95 percent by weight; (b) is present in amounts of 2 to 30 percent by weight and (c) is present in amounts of 0.1 to 10 percent by weight; the percentages are by weight based on total weight of (a), (b) and (c). 
     
     
         14 . A method of preparing the thermosetting powder coating composition of  claim 8  which comprises a step of blending the ingredients of the coating composition. 
     
     
         15 . The method of  claim 14 , comprising dry blending the ingredients to provide an admixture, melt blending the admixture in an extruder, extruding the melt blended admixture, cooling the melt blended extrudate and pulverized the cooled melt blended extrudate. 
     
     
         16 . A method of coating a substrate with the powder coating composition of  claim 8  comprising the steps of:
 (i) applying the powder coating composition to the substrate; and 
 (ii) curing the coating on the substrate. 
 
     
     
         17 . The method of  claim 16 , where in step (i) the coating is applied by electrostatic spraying. 
     
     
         18 . The method of  claim 16 , where in step (ii) curing is effected by heating the coating on the substrate. 
     
     
         19 . A substrate coated at least in part with the powder coating composition of  claim 8 . 
     
     
         20 . The substrate of  claim 19 , wherein the substrate is a vehicle. 
     
     
         21 . The substrate of  claim 19 , wherein the substrate is a metal can. 
     
     
         22 . The coating of  claim 8 , further comprising a thermoplastic polymer.