| abstract |
The present invention (i) in the first step, (A) optionally isophthalic acid in the form of a C 1 -C 4 alkyl ester and / or terephthalic acid in the form of a C 1 -C 4 alkyl ester (B) oligoethylene glycol of the formula H- (OCH 2 CH 2 ) n -OH, wherein the number-average number of oxyethylene groups is in the range from n to 3.0 to 9.0, 7 to 100 hours at a temperature of 160 ° C. to 240 ° C. and a pressure of 1 to 1013 mbar in the presence of at least one catalyst selected from the group consisting of tin (II) salts, bismuth (II) salts and titanium tetraalkoxylates. React for a period of time, (ii) in the second step, The reaction mixture resulting from step (i) (C) reacting with phthalic acid and / or phthalic anhydride, Process for the preparation of polyester polyols having a concentration of ether groups from 9.0 mol / kg polyester polyol to 22 mol / kg polyester polyol, polyester polyols obtained according to the above process, and their preparations for the production of PUR / PIR rigid foam materials It is about a use. |