Oxazolidone ring containing adducts
Embodiments include oxazolidone ring containing adducts obtainable by combining an aliphatic epoxy compound, an aromatic epoxy compound, and a diisocyanate. Embodiments further include a curable powder coating composition including a resin component and a hardener component, where the resin component includes the oxazolidone ring containing adduct.
1. A curable powder coating composition comprising a resin component and a hardener component, where the hardener component is selected from the group consisting of amines, anhydrides, carboxyl-functional polyesters, and combinations thereof, where the resin component includes an oxazolidone ring containing adduct formed by a method, comprising:
reacting an aliphatic epoxy compound, a first diisocyanate and a catalyst to form a first adduct, wherein the aliphatic epoxy compound is a polyglycidyl ether of aliphatic polyols or alkylene-oxide adducts thereof; and
reacting a second diisocyanate with a mixture of the first adduct and an aromatic epoxy compound to form the oxazolidone ring containing adduct, wherein where the aliphatic epoxy compound is 20 weight percent (wt %) to 60 wt % of a total weight of the oxazolidone ring containing adduct, the aromatic epoxy compound is 20 wt % to 40 wt % of the total weight of the oxazolidone ring containing adduct, and the first and second diisocyanate are 10 wt % to 40 wt % of the total weight of the oxazolidone ring containing adduct such that the aliphatic epoxy compound, the aromatic epoxy compound, and the diisocyanate weight percents sum to 100 wt % of the oxazolidone ring containing adduct.
2. The curable powder coating composition of claim 1 , where the oxazolidone ring containing adduct has an epoxide equivalent weight of 800 grams/equivalent (g/eq) to 1300 g/eq, a melt viscosity at 150 degrees Celcius (° C.) of 2 pascal second (Pa·s) to 10 Pa·s, a softening point of 80° C. to 100 ° C. and a glass transition temperature of 35° C. to 55° C.
3. The curable powder coating composition of claim 1 , where the aliphatic epoxy compound is selected from the group consisting of a diglycidyl ether of polypropylene glycol, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and combinations thereof; the aromatic epoxy compound is selected from the group consisting of a glycidyl ether of bisphenol A, a glycidyl ether of bisphenol F, and combinations thereof; and the first and second diisocyanates are each selected from the group consisting of 4,4′-diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, 4,4′-methylenebis(cyclohexylisocyanate), and combinations thereof.