| 摘要 |
Novel solvent based, thermosetting coating compositions comprising epoxy ester resin and blocked polyisocyanate crosslinking agent. The epoxy ester resin used in the composition has a number average molecular weight (Mn) of about 900 to about 5000 and is the reaction product of diepoxide, for example bisphenol-A epichlorohydrin epoxy resin, with (i) diphenol, for example bisphenol A, in chain extension reaction, (ii) dicarboxylic acid, for example the dimer acid reaction product of the dimerization of C-18 fatty acid, in chain extension reaction and (iii) fatty acid, for example Soya fatty acid, in chain terminating esterification reaction, which chain extension reaction and esterification reaction occur at least in part substantially simultaneously and at a temperature reaching at least about 135 DEG C. (275 DEG F.). The blocked polyisocyanate crosslinking agent comprises at least one isocyanato group which has been blocked by reaction with an active hydrogen bearing blocking agent and is included in an amount sufficient to provide about 0.5 to about 1.6 reactive isocyanato groups per reactive group on the epoxy ester resin upon deblocking during cure.
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