Polyurethane-modified alkyd resin

Abstract

A polyurethane-modified alkyd resin obtained by the process consisting of the steps (a) forming an alkyd resin by reacting an unsaturated fatty acid with an aromatic dicarboxylic acid or anhydride, and dimethylolpropionic acid with an excess of polyol, and (b) reacting the alkyd so formed with toluene diisocyanate.

We claim: 
     
       1. An air-drying, water-soluble, polyurethane-modified alkyd resin having superior corrosion resistance and hardness obtained by the steps of: (a) (1) forming an alkyd resin by melting together at 175° F. a mixture of trimethylpentanediol 1170 parts, linoleic acid 1848 parts, and phthalic anhydride 1465 parts,   (2) with agitation adding thereto trimethylolethane 698 parts, dimethylolpropionic acid 567 parts, and dibutyl tin oxide 6.5 parts,   (3) heating the mixture slowly under a nitrogen blanket to 210° C. until an acid number of 52-57 is obtained,   (4) cooling the mixture to 160° C. and adding ethyl benzene 517 parts, cooling to 82° F. and adding methyl ethyl ketone 339 parts, and cooling to 65° C.,   (b).Iadd., .Iaddend.adding thereto toluene diisocyanate 730 parts over a two-hour period, maintaining the temperature at 82° C. or below .Iadd.adding thereto additional toluene diisocyanate 50 parts.Iaddend., then heating to 100°-105° C. for about 1.5 hours, and then diluting with inert solvent. .Iadd. 2. An air-drying water-soluble, polyurethane-modified alkyd resin having superior corrosion resistance and hardness obtained by the steps of:   (a) forming an alkyd resin by reacting at elevated temperatures a fatty acid having 10-20% conjugated unsaturation in an amount of about 30-48% by weight with an aromatic dicarboxylic acid or anhydride thereof in an amount of about 21-30%, and dimethylolpropionic acid in an amount of about 4-11% with a stoichiometrical excess amount of a polyol and   (b) reacting at elevated temperatures the alkyd resin so formed with toluene diisocyanate. .Iaddend. .Iadd. 3. The alkyd resin of claim 2 wherein the fatty acid is present in an amount of 30-36%, the aromatic dicarboxylic acid or anhydride thereof is present in an amount of about 23-28% and the dimethylolpropionic acid is present in an amount of 8.5-10.5%. .Iaddend..Iadd. 4. The alkyd resin of claim 12 wherein the fatty acid is present in an amount of 31-33%, the aromatic dicarboxylic acid or anhydride thereof is present in an amount of 24-27% and the dimethylpropionic acid is present in an amount of 9-10%. .Iaddend..Iadd. 5. The alkyd resin of claim 2 wherein the polyol is supplied by trimethylpentanediol 17-24%, and trimethylolethane 11-15%. .Iaddend..Iadd. 6. The alkyd resin of claim 5 wherein the trimethylpentanediol is present in an amount of 19-22% and the trimethylolethane is present in an amount of 11-13%. .Iaddend..Iadd. 7. The alkyd resin of claim 5 wherein the trimethylpentanediol is present in an amount of 20-21%. .Iaddend..Iadd. 8. An air-drying, water-soluble, alkyd resin modififed by reacting the alkyd resin with toluene disiocyanate, the alkyd portion being obtained by the steps of   (a) reacting at elevated temperatures a fatty acid having 10-20% conjugated unsaturation in an amount of about 30-48% by wt with an aromatic dicarboxylic acid or anhydride thereof about 21-30% and trimethyl pentanediol 17-24% and   (b) adding a thereto trimethylolethane 11-15% and dimethylolpropionic acid 4-11% in the presence of dibutyl tin oxide catalyst and heating until an alkyd resin of acid number 52-57 is obtained..Iaddend.