| 摘要 |
This invention provides novel resin systems and high solids, solvent-based chain-extendable, self-crosslinking coating compositions comprising same. The resin system comprises novel diblocked diisocyanate diurea oligomers of number average molecular weight about 300 to 5000. The resin system further comprises a polyepoxide, preferably a diepoxide, of molecular weight about 100 to 1000 used generally with said oligomer in weight ratio of about 1:1 to about 1:10, respectively. The resin components provide chain-extension polymerization during cure at elevated temperature, in situ, on the surface of a substrate. The resin system is also self-crosslinking. That is, no additional crosslinking component is required to cure the composition. The cured coatings of the invention provide greatly improved physical properties, in particular, greatly improved corrosion resistance.
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