| 摘要 |
PROBLEM TO BE SOLVED: To provide a polyester polyol which shows a viscosity lower than those of conventional polyester polyols and which can be manufactured by an economically profitable method. SOLUTION: The polyester polyol that has a functionality of 1.95-3.25 and a hydroxyl number of 90-33 mgKOH/g, is manufactured by a method comprising (1) a process for reacting (a) a polycarboxylic acid, which has the number of carbons of 4-12 and the number of carboxyl groups of 2-4, with (b) a polyol having a functionality of 2-4 and a molecular weight of 62-400 at 150-250°C to thereby give an end hydroxyl group-bearing polyester polyol Z having a hydroxyl number of 100-40 mgKOH/g and a functionality of 1.95-3.25, then (2) a process for adding to the polyester polyol Z (c) a cyclic ester in a weight ratio of polyester polyol Z to the ester of 10:1-1:1 at the starting temperature of lower than 220°C in such a way that the temperature is not higher than 175°C after 60 minutes or less, and the polyester polyol Z has the hydroxyl number reduced by 5 mgKOH/g or more, and furthermore a hydroxyl group mole ratio of the ester to polyester polyol Z is 0.75:1-10:1. COPYRIGHT: (C)2008,JPO&INPIT |
