Continuous preparation method for polyether glycol

Abstract

The invention is a continuous preparation method of the polyether polyol; the starting reagent containing the DMC catalyst is added into the reaction kettle; the air is removed with nitrogen; the method is to vacuum, stir, raise the temperature, and the epoxy compound is continuously added into the reaction kettle to make the reaction kettle have the inducing pressure; when the temperature is raised and the pressure is lowered in the reaction kettle, the epoxy compound is continued to to be added into the reaction kettle; the temperature is kept in the reaction between 90 and 200 Celsius system, the pressure between minus 0.05 and 1.0 MPa. Then the starting reagent containing the bimetallic cyanide catalyst and the epoxy compound are added into the reaction kettle according to the proportion at the same time. When the reaction kettle is full, the reaction materials flow into the aging kettle to continue to react; the temperature of the aging kettle is kept between 100 and 180 Celsius system. The polyether polyol product enters the product storage tank after being discharged out of the aging kettle. The polyether polyol produced in the method of the invention has the narrow molecular weight distribution, the low non-saturation degree and the stable quality; the method can use the polyether polyol of the low molecular weight as the starting reagent, and can also directly use the small-molecule polyol as the starting reagent.

Description

technical field [0001] The invention relates to a method for preparing polyether polyol, specifically, a method for continuously preparing polyether polyol. Background technique [0002] Polyether polyols are mainly used in the field of polyurethane materials for the production of polyurethane soft foam, hard foam and polyurethane coatings, adhesives, sealants, elastomers and other products, and its consumption accounts for about 80% of the total production of polyether polyols. In addition, polyether polyols are mainly used in the production of foam stabilizers, defoamers, demulsifiers and lubricants. [0003] The double metal cyanide (DMC) catalyst has the characteristics of strong catalytic activity, fast reaction speed, and can react at a lower temperature. The polyether polyol prepared by DMC has the following advantages: the range of number average molecular weight regulation is wide, and high Molecular weight polyether polyol; the product has low unsaturation, which ...

AI Technical Summary

Problems solved by technology

There are many disadvantages in batch production, mainly the low utilization rate of the reaction tank, long production cycle, unstable quality indicators between batches, etc.

In addition, in the batch method, the DMC catalyzed polymerization system generally has a shortcoming: it is not possible to directly use small molecule polyhydric alcohols such as propylene glycol and glycerin as the initiator during polymerization, otherwise there will be a very long induction period in the initial stage of the reaction.

Unsaturation is one of the important indicators to measure the quality of polyether polyols. During the synthesis of polyether polyols, there is a side reaction of epoxide isomerization to generate allyl alcohol, which leads to the formation of monohydric alcohols with low relative molecular weight. , thereby reducing the average molecular mass and functionality of polyether polyols

This -hydric alcohol will play a variety of adverse effects in the synthesis of polyurethane materials

Such as: it limits the growth of the relative molecular weight of polyurethane and has adverse effects on the physical and mechanical properties of the final product

It will also reduce the weather resistance of polyurethane, which is prone to degradation under ultraviolet radiation, etc.

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