| 摘要 |
<p>A scratch-resistant polyurethane coating for safety windows is made by curing a sheet of a liquid composition comprising (1) a polyglycol ether resulting from the condensation of propylene oxide with trimethylolpropane and containing 10.5%-12.0% free hydroxyls and (2) a biuret of 1,6-hexamethylene-diisocyanate, having 21-22% isocyanate groups, the weight ratio of said biuret to said polyglycol ether being about 0.9-1.1.</p> |
