US EPA

1195961 

Journal Article 

ALIPHATIC ISOCYANATES BLOCKED WITH VOLATILE ALCOHOLS FOR DECORATIVE COATINGS 

Huang, Y; Chu, GB; Nieh, M; Jones, FN 

1995 

Yes 

Journal of Coatings Technology
ISSN: 0361-8773 

67 

842 

33-40 

English 

WOS:A1995QP92100003 

Aliphatic polyisocyanates blocked with simple aliphatic alcohols, such as methanol and ethanol, are widely thought to require baking temperatures and times that are too high and/or too long for application of decorative coatings under production conditions. Here we show that polyisocyanates blocked with these alcohols can, when catalyzed with organotin catalysts, crosslink an acrylic polyol at temperatures comparable to those of commercial ε-caprolactam blocked crosslinkers. With 0.5% of dibutyl tin diacetate catalyst, methanol blocked 1,3-bis (1-isocyanato-1-methylethyl) benzene (TMXDI) and methanol blocked hexamethylene diisocyanate isocyanurate are effective crosslinkers for an acrylic polyol at 145 to 155°C. It is theorized that physical factors (blocking agent diffusion rate and volatility) strongly influence cure response.