Crosslinking agent based on linear hydroxypolyallyl ether

Abstract

An allyl type crosslinking agent for use in production of a super water-absorbent polymer comprising a polymerizable compound having a carbon-carbon double bond or a salt thereof, comprising a linear hydroxypolyallyl ether having at least one hydroxyl groups and at least two allyl groups obtained by allyletherification of hydroxyl groups in a linear polyol compound selected from the group consisting of erythritol, xylitol and sorbitol, is provided. This allyl type crosslinking agent is highly soluble in an aqueous solvent, and can give an excellent super water-absorbent polymer, which cannot be obtained in the prior arts, having high levels of both of water absorptivity under atmospheric pressure and water absorptivity under pressurized conditions are obtained.

1 . A crosslinking agent for use in the production of a super water-absorbent polymer comprising a polymerizable compound having a carbon-carbon double bond or a salt thereof, comprising a linear hydroxypolyallyl ether having at least one hydroxyl group and at least two allyl groups obtained by allyletherification of a hydroxyl group in a linear polyol compound which has a straight-chain carbon skeleton, which has carbon atoms each having one hydroxyl group, and which is represented by the formula (1):  
       HOCH 2 [CH(OH)] n CH 2 OH  (1)  
       wherein n is an integer of from 2 to 8.  
     
     
         2 . The crosslinking agent according to  claim 1 , wherein the linear polyol compound is selected from the group consisting of erythritol, xylitol and sorbitol.  
     
     
         3 . The crosslinking agent according to  claim 1 , wherein the linear polyol compound is sorbitol.  
     
     
         4 . The crosslinking agent according to  claim 1 , wherein the linear polyol compound is sorbitol triallyl ether or sorbitol tetraallyl ether.  
     
     
         5 . The crosslinking agent according to anyone of  claims 1  to  4 , wherein the super water-absorbent polymer is crosslinked in an aqueous medium.  
     
     
         6 . The crosslinking agent according to anyone of  claims 1  to  4 , wherein the polymerizable compound has also a carboxyl group.