Method for producing water-absorbing composite

Abstract

According to this invention, there are provided a process for manufacturing a water-absorbing composite comprising the steps of: (A) spraying an aqueous monomer solution containing acrylic acid and/or its salt on a heat-raised fibrous substrate to apply droplets of the aqueous monomer solution on the fiber constituting the fibrous substrate; (B) polymerizing the monomers in the droplets to form a water-absorbing composite in which the water-absorbing resin particles adhere to the fiber; a process for manufacturing a thermally-compressed water-absorbing composite further comprising step (C): further thermally compressing the above water-absorbing composite; and a process for manufacturing a laminated water-absorbing composite further comprising step (D): laminating the water-absorbing composite and a fibrous substrate to form a laminate and then thermally compressing the laminate to thermally fuse the water-absorbing composite and the fibrous substrate.

1 . A process for manufacturing a water-absorbing composite comprising the steps of: 
 (A) spraying an aqueous monomer solution containing acrylic acid and/or its salt on a heat-raised fibrous substrate to apply droplets of the aqueous monomer solution on the fiber constituting the fibrous substrate;    (B) polymerizing the monomers in the droplets to form a water-absorbing composite in which the water-absorbing resin particles adhere to the fiber constituting the fibrous substrate.    
   
   
       2 . A process for manufacturing a water-absorbing composite comprising the steps of: 
 (A) spraying an aqueous monomer solution containing acrylic acid and/or its salt on a heat-raised fibrous substrate to apply droplets of the aqueous monomer solution on the fiber constituting the fibrous substrate;    (B) polymerizing the monomers in the droplets to form a water-absorbing composite in which the water-absorbing resin particles adhere to the fiber constituting the fibrous substrate; and    (C) thermo-compressing the water-absorbing composite prepared in step (B).    
   
   
       3 . The process for manufacturing a water-absorbing composite as claimed in  claim 1 , wherein the amount of the water-absorbing resin particles adhering to the fibrous substrate is 100 g/m 2  or more.  
   
   
       4 . The process for manufacturing a water-absorbing composite as claimed in  claim 1 , wherein the amount of the water-absorbing resin particles adhering to the fibrous substrate is 250 to 500 g/m 2  or more.  
   
   
       5 . The process for manufacturing a water-absorbing composite as claimed in  claim 1 , wherein the aqueous monomer solution contains a crosslinking agent in 1000 to 5000 ppm to the amount of the monomers.  
   
   
       6 . The process for manufacturing a water-absorbing composite as claimed in  claim 1 , wherein the fibrous substrate to be sprayed with the aqueous monomer solution is an unwoven fabric with a tensile strength of 50 to 300 g/25 mm.  
   
   
       7 . A process for manufacturing a laminated water-absorbing composite comprising the steps of: 
 (A) spraying an aqueous monomer solution containing acrylic acid and/or its salt on a heat-raised fibrous substrate to apply droplets of the aqueous monomer solution on the fiber constituting the fibrous substrate;    (B) polymerizing the monomers in the droplets to form a water-absorbing composite in which the water-absorbing composite in which the water-absorbing resin particles adhere to the fiber constituting the fibrous substrate; and    (D) laminating the water-absorbing composite prepared in step (B) and a fibrous substrate to form a laminate and then passing the laminate between a pair of rollers, at least one of which is heated, for thermally compressing the laminate to integrate combine the water-absorbing composite and the fibrous substrate by thermal fusion.    
   
   
       8 . The process for manufacturing a laminated water-absorbing composite as claimed in  claim 7 , wherein at least one of the pair of rollers has a surface with an uneven pattern.  
   
   
       9 . The process for manufacturing a water-absorbing composite as claimed in  claim 2 , wherein the amount of the water-absorbing resin particles adhering to the fibrous substrate is 100 g/m 2  or more.  
   
   
       10 . The process for manufacturing a water-absorbing composite as claimed in  claim 2 , wherein the amount of the water-absorbing resin particles adhering to the fibrous substrate is 250 to 500 g/m 2  or more.  
   
   
       11 . The process for manufacturing a water-absorbing composite as claimed in  claim 2 , wherein the aqueous monomer solution contains a crosslinking agent in 1000 to 5000 ppm to the amount of the monomers.  
   
   
       12 . The process for manufacturing a water-absorbing composite as claimed in  claim 2 , wherein the fibrous substrate to be sprayed with the aqueous monomer solution is an unwoven fabric with a tensile strength of 50 to 300 g/25 mm.