Process for preparation of polymer polyols

The present invention relates to the use of a hydrofoil impeller for the preparation of a polymer polyol, and to a process for the preparation of a polymer polyol, said process comprising the preparation of a polymer polyol in the presence of a free-radical initiator and optionally a chain transfer agent, a base polyol, at least one ethylenically unsaturated monomer, and a macromonomer or a preformed stabilizer are reacted in a reactor, where the reactor is stirred by a stirring system, the stirring system includes a shaft rotatable about its longitudinal axis and a plurality of radially extending hydrofoil impellers mounted on the shaft and axially spaced apart, respectively, and wherein the reactor does not include a baffle. 本发明涉及水翼叶轮用于制备聚合物多元醇的用途，并且涉及用于制备聚合物多元醇的方法，所述方法包括在自由基引发剂和任选的链转移剂的存在下，在反应器中使基础多元醇、至少一种烯键式不饱和单体和大分子单体或预形成的稳定剂反应，其中所述反应器通过搅拌系统搅拌，所述搅拌系统包括可绕其纵向轴线旋转的轴和安装在轴上并分别轴向间隔开的复数个径向延伸的水翼叶轮，并且其中反应器不包括挡板。