Miller & Prestia
Polyurethane resins and polyurethane resin coating compositions
 Polyurethane resins with an excellent weather resistance are provided by the reaction of polyols with trifunctional isocyanates which are expressed by the following general formula: ##STR1## (R=a remnant of divalent hydrocarbon group with carbon number of 2 or 3) The reaction between a polyol and a trifunctional isocyanate is effectuated at an NCO/OH mole percentage of 0.5 to 2.0, and adjustments are made so that the concentration of carbamide group will be 5.times.10.sup.-4 to 50.times.10.sup.-4 moles per gram of the reaction product, and that the bridging parameter will be 150 to 1,500. The resins may be used to best advantage as polyurethane resin coatings excelling in weather resistance. 
Toray Industries, Inc.
C
C08G
inventional
Sadayuki Tadanori Masami
Sakamoto Fukuda Saito