IMPROVED EPOXIDE POLYMERIZATION PROCESS

摘要

The amount of high molecular weight impurity present in a polyether polyol produced by alkoxylation of an active hydrogen-containing initiator using an epoxide such as propylene oxide and a substantially amorphous highly active double metal cyanide complex catalyst may be advantageously lowered by havin g a non-protic Lewis acid present during the epoxide polymerization. The use o f halides such as zinc chloride and aluminum chloride is especially effective for such purposes. In a preferred embodiment, minor amounts of water are als o present during polymerization. The higher purity polyether polyols thereby produced are particularly useful in the preparation of slab and molded polyurethane foams, which tend to collapse or become excessively tight when elevated levels of high molecular tail are present in the polyether polyol.< /SDOAB>