Preparation method of polyether polyol with high molecular weight, low unsaturation degree and high primary hydroxyl group content

Abstract

The invention relates to a preparation method of polyether polyol with high molecular weight, low unsaturation degree and high primary hydroxyl group content, belonging to the field of chemical engineering. According to the preparation method, a treating agent is used for treating the polyether polyol with high molecular weight and low unsaturation degree, which contains bimetallic catalyst DMC; ethylene oxide is added for end capping; an adsorbent is used for treating the product of the end capping; filtration is finally carried out to obtain the polyether polyol with high molecular weight, low unsaturation degree and high activity, wherein the molecular weight of the polyether polyol is 8000-15000 and the primary hydroxyl group mole fraction is 85-93%. The prepared polyether polyol with high molecular weight, low unsaturation degree and high primary hydroxyl group content has the characteristics of high activity, short demoulding time and good physical mechanical property; by using the polyether polyol as a raw material, the prepared high-resilience moulding foam product is suitable for the preparation of various automotive trim materials. The invention expands the application of the polyether polyol to PU big high-resilience foam and one-step moulding foam.

Description

technical field [0001] The invention belongs to the field of chemical industry and relates to a preparation method of polyether polyol with high molecular weight, low unsaturation, high primary hydroxyl content and high activity. Background technique [0002] Ordinary polyether polyol (PPG) has a series of problems such as low molecular weight, high unsaturation and insufficient activity, which lead to poor product quality and application performance, which limit the application field of PPG. When the relative molecular weight of PPG is higher, the number of hydroxyl groups becomes smaller, and the relative content of primary hydroxyl groups must be increased to improve the reactivity of the product. The activity of the primary hydroxyl group is three times that of the secondary hydroxyl group. The PPG with primary hydroxyl group can shorten the curing time during foam molding. [0003] Highly active polyether prepared by traditional basic compound catalyst has high degree ...

AI Technical Summary

Problems solved by technology

Although polyether polyols made with bimetallic catalysts (DMC) have the advantages of narrow molecular weight distribution, adjustable molecular weight, low unsaturation, and low viscosity, DMC has high catalytic activity. During the (EO) addition reaction, the chain growth rate of EO is faster than the chain transfer rate. As a result, some polyethylene oxide branch chains in the PPG finished product are very long, and some chain segments have fewer EO chains, or even no

In this way, the length of the molecular chain is uneven, the distribution of EO is uneven, and the primary hydroxyl content of the polyether is low.

Therefore, at present, when using EO end-capping to increase the number of primary hydroxyl groups, satisfactory results cannot be achieved with DMC catalysts, and alkali-based or acid-based catalysts are still required.

[0004] Usually, in the presence of a basic catalyst, EO is used to end-cap PPG to obtain terminal primary hydroxyl PPG, but this technology cannot be simply extended to the process using DMC catalyst. When EO is added to PPG containing DMC catalyst, the obtained A heterogeneous mixture of unblocked PPG, polyethylene glycol and a very small amount of high-capped PPG