METHOD FOR PRODUCING POLYETHER CARBONATE POLYOLS

摘要

The present invention relates to a method for producing polyether carbonate polyols, wherein: (i) in a first step, (a) carbon dioxide and propylene oxide or (b) carbon dioxide and a mixture of propylene oxide and at least one further alkylene oxide in a ratio by weight of >90:10 are attached to one or more H-functional starting substances in the presence of at least one DMC catalyst; ii) in a second step, the reaction mixture obtained from step (i) is (ii-1) first chain-lengthened with a mixture containing propylene oxide (PO) and ethylene oxide (EO) in a PO/EO ratio by weight of 90/10 to 20/80 in the presence of at least one DMC catalyst.

主权项

1. A process for preparing polyether carbonate polyol, comprising
(i) adding
(a) carbon dioxide and propylene oxide or(b) carbon dioxide and a mixture of propylene oxide and at least one further alkylene oxide in a weight ratio of >90:10onto one or more H-functional starter substance(s) in the presence of at least one DMC catalyst, (ii) a reaction mixture obtained from (i)
(ii-1) is first chain-extended with a mixture comprising propylene oxide (PO) and ethylene oxide (EO) in a PO/EO weight ratio of 90/10 to 20/80 in the presence of at least one DMC catalyst,(ii-2) then a resulting mixture is chain-extended with a mixture comprising propylene oxide (PO) and ethylene oxide (EO) in a PO/EO weight ratio of 60/40 to 2/98 in the presence of at least one DMC catalyst, and (iii) polyether carbonate polyol resulting from (ii) is chain-extended with ethylene oxide or a mixture of propylene oxide (PO) and ethylene oxide (EO) in a PO/EO weight ratio of 5/95 to 0.1/99.9 in the presence of at least one DMC catalyst, where the proportion by weight of EO in a mixture comprising PO and EO in (ii-2) is higher than the proportion by weight of EO in mixture comprising PO and EO in (ii-1).