PROCESS FOR THE PRODUCTION OF POLYOXYMETHYLENE BLOCK COPOLYMERS

摘要

The invention relates to a process for producing polyoxymethylene block copolymers, comprising the step of activating the DMC catalyst in the presence of an OH-terminated polymeric formaldehyde starter compound by means of a defined amount of alkylene oxide, optionally followed by polymerization with alkylene oxides, if necessary in the presence of other comonomers. The invention further relates to polyoxymethylene block copolymers that can be obtained by means of such a process and to the use of these for producing polyurethane polymers.

主权项

1. A process for preparing polyoxymethylene block copolymers comprising catalytically adding one or more alkylene oxides and optionally additional comonomers onto at least one polymeric formaldehyde starter compound having at least one terminal hydroxyl group, in the presence of a double metal cyanide (DMC) catalyst, which comprises
(i) activating the DMC catalyst in the presence of the polymeric formaldehyde starter compound, in which activation of the DMC catalyst is accomplished by adding a portion, based on the totality of the amount of alkylene oxides used in the activation and polymerization, of one or more alkylene oxides, and (ii) adding one or more alkylene oxides and optionally additional comonomers to the mixture resulting from (i), in which the alkylene oxides used in (ii) may be the same as or different than the alkylene oxides used in (i), wherein the activation of the DMC catalyst in (i) is effected at an activation temperature (Tact) of 20 to 120° C.