Thixotropic alkyd resin compositions

An air drying alkyd resin based thixotropic composition (I) contains (A) 75-98 wt.% alkyd resin or modified alkyd resin having an oil content of 20-90 % and (B) 2-25 wt.% of a thixotropic agent prepared by reaction of an isocyanate functional reaction product (B1) of a multi-functional isocyanate (B11) with an olefinically unsaturated hydroxy functional compound (B12) consisting of a hydroxyalkylester of an aliphatic alpha , beta -unsaturated carboxylic acid or an alpha , beta -unsaturated dicarboxylic acid having 2-10C atoms in the hydroxyalkyl group and alkoxylation products of (meth)acrylic acid to a degree of alkoxylation of 10 moles alkylene oxide per mole of (meth)acrylic acid with an amine component (B2) consisting of a (poly)amine or ammonia. Whereby the ratio of the number of isocyanate groups; in (B11) to the number of hydroxy groups in (B12) is 1:0.3-1:0.8 for the production of (B1) and the remaining isocyanate groups in (B1) react fully with the amine component (B2). An Independent claim is included for a process for the production of (I) by mixing 75-98 wt.% (A) and 2-25 wt.% (B). POLYMERS - Preferred Composition: A 3-22C linear branched or cyclic monoalcohol or aralaliphatic alcohol, preferably an unsaturated monoalcohol whereby the hydroxy group is bonded to an aliphatic carbon atom is added to (B11) and (B12). The multi-functional isocyanate (B11) is a linear, or cyclic aliphatic or aromatic compound having at least 2 isocyanate groups per molecule or is a mixture of isocyanates having an average isocyanate functionality of at least 1.8. (B12) is a hydroxyalkyl(meth)acrylate having 2-4C atoms in the alkyl group or is an alkoxylated product of acrylic and/or methacrylic acid having up to 10 moles of alkylene oxide per mole of (meth)acrylic acid, whereby the alkylene oxide is ethylene oxide and /or propylene oxide is a 4-10C prim. diamine or a polyoxyalkylene-polyamine having a wt. average mol. wt. of 200-800 g/mole. Preferred Process: The reaction of (B1) and (B2) is carried out in the presence of at least 25 wt.% of (A).