| 摘要 |
<p>1,222,158. Polyurethane coating compositions. TAKEDA CHEMICAL INDUSTRIES Ltd. 23 May, 1968 [23 May, 1967 (2)], No. 24743/68. Headings C3P and C3R. [Also in Divisions B1-B2] Two-can polyurethane coating compositions comprise a polyester polyol component and an isocyanate component which is an adduct produced by reacting trimethylolpropane with dimethylbenzene-#,#<SP>1</SP>-diisocyanate in a molar ratio of the former to the latter of 1 : 7 to 1 : 16 and removing unreacted dimethylbenzene- #,#<SP>1</SP>-diisocyanate. The polyester polyol may be (a) a fatty acid-modified polyester polyol having 4 to 7 OH groups in the molecule, a molecular weight of 200 to 600 per OH group and terminal mono or diglyceride groups; (b) a copolymer having a M.W. of 1500 to 8000 and an OH number of 30 to 180 and being the reaction product of hydroxyethyl methacrylate and a compound of formula where R is hydrogen or a methyl radical and R<SP>1</SP> is a C 1-4 alkyl radical, with or without styrene, (c) a saturated polyester polyol which has 3 OH groups in the molecule and a M.W. of 250 to 500 per OH group and which is prepared by reacting adipic acid, a C 2-8 glycol and a C 3-6 triol, or (d) an isocyanate modified polyester polyol produced by reacting (i) a polyester of M.W. 500 to 3000 and which is prepared by reacting adipic acid and a C 2-10 glycol with or without a C 3-6 triol, and (ii) dimethylbenzene- #,#<SP>1</SP>-diisocyanate, with or without a C 2-10 glycol in a molar ratio of 0À95#NCO.OH< 1À0. The reaction between the trimethylolpropane and dimethylbenzene - #,#<SP>1</SP> - diisocyanate is suitably conducted at 60‹ to 80‹ C. and the unreacted diisocyanate removed by extraction with a solvent. Additives such as pigments or dyes, solvents, viscosity regulators, fillers, antioxidants and levelling agents may be added preferably to the polyester component before admixture with the isocyanate component. As the dimethylbenzene-#,#<SP>1</SP>-diisocyanate, any of the ortho, meta and paracompounds, or a mixture thereof may be used. The preparation of several polyesters of the classes (a), (b), (c) and (d) is described.</p> |
