A series of new oligomeric polyorthoesters for low-VOC coatings was prepared by protecting OH groups with orthoester compounds to achieve both low viscosity and excellent compatibility with cross-linking agents. These new oligomeric polyorthoesters were synthesized through co-condensation reaction among polyol, orthoester, and α or β - glycol compounds under an acidic condition. Here, the α or β- glycol compounds were used as stoppers to prevent excessive polymerization. The polyorthoesters can easily be hydrolyzed with atmospheric moisture, and the reproduced OH groups can react with appropriate cross-linking agents. It is unique in this system that even the stoppers, α or β - glycol compounds, can react with the cross-linking agents to achieve an extremely low VOC emission. The polyorthoesters cured with polyisocyanate compounds proved to be highly cross-linked polymers showing excellent mechanical properties, chemical resistance, etc.
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