Thermally curable, thixotropic blends containing carbamate and/or allophanate groups

Abstract

Heat-curable thixotropic mixtures containing carbamate and/or allophanate groups, comprising (A) at least one oligomer and/or polymer selected from the group consisting of oligomers and polymers containing allophanate groups, carbamate groups, and carbamate and allophanate groups, and (B) at least one thixotropic agent selected from the group consisting of urea derivatives preparable by reacting at least one amine and/or water with at least one isocyanate in the presence of at least one amino resin; processes for preparing the mixtures, and their use as coating materials, adhesives and sealing compounds.

What is claimed is:  
     
         1 . A heat-curable thixotropic mixture containing carbamate and/or allophanate groups, comprising 
 (A) at least one oligomer and/or polymer selected from the group consisting of oligomers and polymers containing allophanate groups, carbamate groups, and carbamate and allophanate groups, and    (B) at least one thixotropic agent selected from the group consisting of urea derivatives preparable by reacting at least one amine and/or water with at least one isocyanate in the presence of at least one amino acid.    
     
     
         2 . The mixture as claimed in  claim 1 , wherein the urea derivatives (B) are preparable by reacting at least one monoamine with at least one polyisocyanate or by reacting at least one polyamine with at least one monoisocyanate.  
     
     
         3 . The mixture as claimed in  claim 1  or  2 , wherein the amines are selected from the group consisting of acyclic aliphatic, aliphatic-aromatic, cycloaliphatic, aliphatic-cycloaliphatic, and cycloaliphatic-aromatic, primary and secondary monoamines and polyamines.  
     
     
         4 . The mixture as claimed in  claim 3 , wherein the amines are selected from the group of the monoamines.  
     
     
         5 . The mixture as claimed in any of  claims 1  to  5 , wherein the polyisocyanates contain on average per molecule at least 1.8 isocyanate groups.  
     
     
         6 . The mixture as claimed in any of  claims 1  to  5 , comprising at least one silica as thixotropic agent (C).  
     
     
         7 . The mixture as claimed in any of  claims 1  to  6 , comprising at least one wetting agent (D).  
     
     
         8 . The mixture as claimed in any of  claims 1  to  7 , wherein the oligomers and polymers (A) are selected from the group consisting of random, alternating and block, linear and branched and comb addition (co)polymers of ethylenically unsaturated monomers, and polyaddition resins and polycondensation resins.  
     
     
         9 . The mixture as claimed in  claim 8 , wherein the addition (co)polymers (A) are selected from the group consisting of (meth)acrylate copolymers and polyvinyl esters and the polyaddition resins and polycondensation resins are selected from the group consisting of polyesters, alkyds, polyurethanes, polylactones, polycarbonates, polyethers, epoxy resin-amine adducts, polyureas, polyamides and polyimides.  
     
     
         10 . The mixture as claimed in any of  claims 6  to  9 , wherein the silicas (C) are selected from the group consisting of modified pyrogenic, hydrophilic and hydrophobic, transparent silicas.  
     
     
         11 . The mixture as claimed in any of  claims 7  to  10 , wherein the wetting agents are selected from the group consisting of siloxanes, fluorine compounds, carboxylic half-esters, phosphates, polyacrylic acids and their copolymers, and polyurethanes.  
     
     
         12 . The mixture as claimed in any of  claims 1  to  11 , comprising at least one crosslinking agent containing on average per molecule at least two reactive functional groups which are complementary to carbamate groups and allophanate groups.  
     
     
         13 . The mixture as claimed in any of  claims 1  to  12 , wherein the oligomers and polymers (A) contain on average per molecule at least one reactive functional group which is complementary to carbamate groups and allophanate groups.  
     
     
         14 . The mixture as claimed in  claim 12  or  13 , wherein the complementary reactive functional groups are selected from the group consisting of N-methylol groups and N-methylol ether groups.  
     
     
         15 . A process for preparing a heat-curable thixotropic mixture containing carbamate and/or allophanate groups as claimed in any of  claims 1  to  14  by mixing of the constituents (A) and (B) and, where appropriate, (C), (D), at least one crosslinking agent and/or at least one additive, which comprises preparing the thixotropic agent (B) by reacting at least one amine and/or water with at least one polyisocyanate or by reacting at least one polyamine with at least one monoisocyanate in the presence of at least one amino resin.  
     
     
         16 . The use of the heat-curable thixotropic mixture containing carbamate and/or allophanate groups as claimed in any of  claims 1  to  14  as a coating material, adhesive or sealing compound.  
     
     
         17 . The use as claimed in  claim 16 , wherein the coating material is used as a clearcoat material.  
     
     
         18 . The use as claimed in  claim 16  or  17 , wherein the coating material, adhesive or sealing compound is used in the fields of automotive OEM finishing, automotive refinish, the coating of buildings, inside and out, the coating of furniture, windows and doors, and industrial coating, including coil coating, container coating, the impregnation or coating of electrical components and the coating of white goods, including domestic appliances, boilers and radiators.