| 摘要 |
A method for the manufacture of polyester polyols is disclosed. The method comprises feeding to a reactor at least one aliphatic carboxylic acid or ester thereof, at least one secondary dihydric alcohol and at least one primary trihydric alcohol, heating the resultant admixture and removing water. When at least 95% of the water has been removed, N-phenyl dialkanolamine and additional primary trihydric alcohol are added and heating is continued. The reactants are selected so that the range of molecular weights thereof is not more than 100. A block polyester polyol is obtained. Polyurethanes obtained from the polyester polyol tend to have more uniform and superior properties. The polyurethanes may be used in variety of end uses.
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