Patent ID: 7728075

Claim:
Coating composition for the manufacture of a car wash-resistant coating comprising at least one hydroxyl-functional binder selected from the group of hydroxyl-functional acrylic binders and hydroxyl-functional polyester binders and one or more cross- linkers reactive with the reactive groups of the binder, wherein the binder and cross-linkers are selected such that, after curing to a coating, the coating has an initial gloss of at least 81 GU and a loss of gloss (LoG) of less than 0.18, the loss of gloss being determined by the formula (I) LoG= A+B·E′ ·( X ) −1 ·10 (C·ΔTg) +D· ( E′ ) −0.5 (I) wherein A=0.0132, B=1.0197, C=0.0113, and D=0.0566, E′ reflects the tensile storage modulus at 40° C. in GPa, ΔTg the width of the glass transition temperature in °C., and X the cross-link density parameter in kPa/K, all three parameters determined in a DMTA test at 11 Hz and a heating rate of 5° C./min. and wherein, in case the at least one hydroxyl-functional binder is an acrylic binder, the acrylic binder comprises (1) at least 20 wt % based on the total weight of the monomers of hydroxyl group-containing monomers selected from the group of primary hydroxyl group-containing monomers or hydroxyl cycloalkyl group-containing monomers, this acrylic binder comprises (2) more than 10 mole % of monomers selected from the group of non-OH-functional low Tg monomers with a monomer Tg not exceeding 253K for acrylic non-OH-functional monomers, or not exceeding 293 K for methacrylic or non-acrylic non-OH-functional monomers, and wherein (3) the average number of atoms between the polymeric backbone of the acrylic binder and the oxygen atom of the hydroxyl group is at least 6, and (4) the acrylic binder has an OHV value of between 80 and 250 mg KOH/g.