Preparation of polyester-ether polyols

Abstract

The invention relates to preparation of polyester-ether polyols. The polyester-ether polyols are prepared from main raw materials including pyromellitic dianhydride and diol through esterification andetherification reactions. The method comprises steps as follows: pyromellitic dianhydride, small-molecular diols and a catalyst are added to a polyester reaction bottle and slowly heated to 120-140 DEG C under the protection of n2. When the acid value of a product is smaller than or equal to 1.5 mg koh / g, the reaction is stopped; filter pressing and discharging are performed when the temperatureis reduced to 90 DEG C or below, a filtrate is obtained, and pyromellitic acid type polyester polyols are obtained; (2) pyromellitic acid type polyester polyols and an amine catalyst are added to a polyether reaction kettle and treated under reduced pressure; propylene epoxide is added to the reaction kettle, the mixture is slowly heated to 100-130 DEG C, the pressure in the kettle is kept at 0.07-0.4 mpa, a reaction is performed at the temperature and under the pressure for 1-4 h, vacuum pumping is performed, filter pressing and discharging are performed when the temperature is reduced to 90DEG C or below, and pyromellitic acid polyester-ether polyols can be obtained.

Description

technical field [0001] The invention belongs to the field of chemical synthesis technology, in particular to the production of polyester ether polyols. Background technique [0002] Polyester polyol and polyether polyol are important components of polyurethane foam. Polyester polyol is prepared by reacting dibasic acid or anhydride with diol or polyol. Polyether polyol is based on ethylene oxide, Epoxy compounds such as propylene oxide are the post-polymerization units, and the oligomer polyols are synthesized by ring-opening homopolymerization and copolymerization reactions with polyhydroxyl and amine compounds as initiators. The advantages of polyester rigid foam are high strength, fine foam cells, low thermal conductivity, good adhesion and low price, but polyester itself is viscous, inconvenient to operate, and the foam obtained from polyester has poor hydrolytic stability. Polyether polyol has good hydrolysis stability and good compatibility with other additives in the...

AI Technical Summary

Problems solved by technology

The advantages of polyester rigid foam are high strength, fine foam cells, low thermal conductivity, good adhesion and low price, but polyester itself is viscous, inconvenient to operate, and the foam obtained from polyester has poor hydrolytic stability.

Polyether polyol has good hydrolysis stability and good compatibility with other additives in the formula, but the price of polymerized monomers such as ethylene oxide and propylene oxide used in the preparation of polyether polyol is relatively high, which leads to polyester High price of polyols