Method for producing ο-phthalate polyester polyols with low cyclic ester content

摘要

A method for producing a polyester polyol is disclosed. The method comprises reacting phthalic anhydride with a diol selected from the group consisting of ethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 1,6-hexanediol, polyethylene glycols having a number average molecular weight within the range of 200 g/mol to 600 g/mol, and mixtures thereof at a diol to phthalic anhydride molar ratio within the range of 1.1 to 1.6. The resulting o-phthalate polyester polyol has a hydroxyl value in the range of 18 to 400 mg KOH/g, an acid value in the range of 0.2 to 5.0 mg KOH/g, and 1 wt. % or less of cyclic esters.

主权项

1. A method which comprises reacting phthalic anhydride with a diol selected from the group consisting of propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, neopentyl glycol, polyethylene glycols having a number average molecular weight within the range of 200 g/mol to 600 g/mol, mixtures of ethylene glycol and at least one polyethylene glycol having a number average molecular weight within the range of 200 g/mol to 600 g/mol, and mixtures thereof in the presence of a catalyst comprising titanium at a diol to phthalic anhydride molar ratio within the range of 1.1:1 to 1.6:1 to produce an o-phthalate polyester polyol having a hydroxyl value in the range of 18 to 400 mg KOH/g, an acid value in the range of 0.2 to 5.0 mg KOH/g, and 1 wt. % or less of cyclic esters.