| 摘要 |
<p>Polyurethane coating compsn. is prepd. from (a) polymer contg. ester gps. and free OH gps. consisting of a poly(meth)acrylic acid ester polyol and (b) an isocyanate compsn. made by reacting 1,1,1-trimethylolpropane (I) with 9-12 dimethylbenzene - Omega, Omega'-diisocyanate (II) followed by removal of the unreacted diisocyanate. Reacting the (I) with excess (II) gives isocyanate components with improved properties compared with prior art adducts based on these materials. Use of 9 mols (II) in the initial reaction gives a prod. with inferior toluene tolerance, while the use of >12 moles (II) is uneconomical. The combination of (a) and (b) gives polyurethane lacquers with improved gloss, elongation, tensile strength and anti yellowing properties.</p> |
