Low-temperature curable surface cross-linking agent of super absorbent polymer and preparing method of low-temperature curable surface cross-linking agent of super absorbent polymer

摘要

Disclosed is a preparation method of a low-temperature curing surface crosslinking agent of a superabsorbent resin, which comprises: a first step of mixing polyhydric alcohol and a Lewis acid catalyst at 30-40°C; a second step of adding epichlorohydrin to the mixture of the first step, and making reaction at 60-90°C to obtain halohydrin ether; a third step of adding a quaternary ammonium salt to halohydrin ether obtained in the second step and make reaction at 50-60°C; a fourth step of adding a strongly alkaline aqueous solution to a resultant product of the reaction in the third step to make condensation reaction; a fifth step of dividing the reaction product obtained in the fourth step into a salt layer and a resin layer including epichlorohydrin by using a dry filter at 40-60°C; a sixth step of recovering and removing excess of epichlorohydrin from the resultant product obtained in the fifth step; and a seventh step of adding an alkali absorbent to the resultant product obtained in the sixth step to perform mixing at 65-80°C. The fourth step of making condensation reaction includes: an A step of adding to the reaction product obtained in the third step a strongly alkaline aqueous solution as much as one third of strongly alkaline aqueous solution necessary for reaction with halohydrin ether to remove a salt water layer; and a B step of adding to the reaction product obtained in the A step a strongly alkaline aqueous solution as much as two-thirds of a strongly alkaline aqueous solution necessary for reaction with halohydrin ether to perform a decompression and dehydration process, wherein a reaction temperature in the B step is controlled to increase relative to the reaction temperature of the A step.