| 摘要 |
1356327 Polyurethanes VEBA-CHEMIE AG 2 Sept 1971 [2 Sept 1970] 41034/71 Heading C3R An hydrolysis resistant polyurethane, for use in coating compositions comprises the reaction product of a polyisocyanate with one or more OH-containing polyesters, at least 50 mole per cent of which polyester is a reaction product of 2,2,4- and / or 2,4,4 - trimethylhexanediol (1,6) and terephthalic acid, the remainder of the polyesters being a reaction product of at least one other diol and/or triol with terephthalic acid. Examples of such diols and triols are : ethylene-, propylene- or butylene - glycols, other hexane diols, octadecene - 9,10 - diol (1,12), thiodiglycol, 2,2 - dimethylpropanediol (1,3), octadecanediol, 2 - ethylhexanediol (1,3), 2,4 - dimethyl - 2 - propylheptanediol (1,3), butenediol (1,4), butinediol (1,4), diethylene glycol, triethylene glycol, glycerol and hexanetriol - (1,2,6). A preferred polyisocyanate is 3 - isocyanatomethyl - 3,5,5 - trimethylcyclohexylisocyanate, its trimer or adduct with a polyhydric alcohol. The polyester may contain approximately equal amounts of the 2,2,4- and 2,4,4-isomers of the diol; it may have a M.W. of 1500-2500. Reaction may take place in a solvent. |
