Nanjing Chemical Material Corp.
Polyether polyol is an oligomer whose main chain contains ether bond (-R-O-R-) and whose end or pendant group contains more than two hydroxyl groups (-OH). It is prepared by the ring-opening polymerization with oxidized olefin under the action of catalyst using low molecular weight polyhydric alcohols, polyamines or compounds containing reactive hydrogen as initiators. Polyol initiators include dihydric alcohols such as propylene glycol and ethylene glycol, trihydric alcohols such as glycerinum and trimethylolpropane, and polyhydric alcohols such as pentaerythritol, tetraol, xylitol, sorbitol and cane sugar; amine initiators include diethylamine, diethylenetriamine.
The common polyether polyol is propylene glycol polyether with molecular weight of 800-2000, trimethylolpropane polyether with molecular weight of 400-4000 and hydroxyl-terminated polytetrahydrofuran.
The residual alkaline catalysts should be removed when polyether resin is used as the adhesive, because they can catalyze the dimerization of isocyanate and affect the quality of adhesives. The polyether is usually neutralized with acid to make the polyether slightly acidic (It does not affect the reaction of polyurethane). The polyether used for preparing polyurethane adhesives is more stringent. Besides hydroxyl value and acid value, potassium and sodium ions should be less than 10 and water content is less than 0.05%. Otherwise, gels may be generated. The polyurethane adhesive prepared with polyether resin has good water resistance, impact resistance and low temperature resistance.
Polyether polyol with different functionalities can be prepared according to the number of active atoms in the initiator. The most commonly used polyethers in the preparation of polyurethane adhesives are propylene oxide glycol, polyoxypropylene triol as well as polytetrahydrofuran glycol.
