Patent ID: 8716515

Claim:
A process for preparing a first polyether ester polyol comprising reacting starting compounds having Zerewitinoff-active hydrogen atoms (a) with at least one alkylene oxide (b) in the presence of at least one amine (c) selected from the group consisting of tertiary amines and optionally substituted imidazole and in the presence of at least one hydroxyl group-free fatty acid ester (d), wherein a second polyether ester polyol (e) is first mixed in amounts of 3.0 to 20.0 weight %, based on all the components (a), (b), (c), (d), and (e), with components (a) and (c), followed by a first metered addition of (b) in an amount from 10 to 70 weight %, based on the total amount of (b) to be metered in; followed by the addition of (d), and followed by a second metered addition of the remainder of (b) in an amount from 30-90 weight %, based upon the total amount of (b) to be metered in, wherein (a) is selected from the group consisting of at least one one of saccharose, pentaerythritol, sorbitol, trimethylolpropane, bisphenol F, bisphenol A, 1,3,5-trihydroxybenzene, isomers of diaminotoluene, isomers of diaminodiphenylmethane, methylol-group-containing condensation products of formaldehyde and phenol, melamine or urea, and Mannich bases, and wherein the at least one alkylene oxide (b) is metered in continuously, and wherein at least 99 wt % of the starting compounds having Zerewitinoff-active hydrogen atoms (a) are incorporated into the polyether ester polyol.