Pigment dispersing resin

Abstract

This invention relates to the use of a copolymer of polymerizable unsaturated monomer containing at least one kind of ionic functional group selected from the group consisting of quaternary ammonium salt group and sulfonic acid group, nonionic polymerizable unsaturated monomer having polyoxyalkylene chain, and other ethylenically unsaturated monomer, as a pigment dispersing resin for water-based paint or water-based ink.

1 . A pigment dispersing resin which is a copolymer of: 
 (A) polymerizable unsaturated monomer containing at least one kind of ionic functional group selected from the group consisting of quaternary ammonium salt group and sulfonic acid group;    (B) nonionic polymerizable unsaturated monomer having polyoxyalkylene chain; and    (C) other ethylenically unsaturated monomer.    
   
   
       2 . A pigment dispersing resin of  claim 1  wherein the ionic functional group-containing polymerizable unsaturated monomer (A) is selected from the group consisting of 2-(methacryloyloxy)ethyl trimethylammonium chloride, 2-(methacryloyloxy)ethyl trimethylammonium bromide, (meth)acryloylaminopropyl trimethylammonium chloride, (meth)acryloylaminopropyl trimethylammonium bromide, tetrabutylammonium(meth)acrylate, trimethylbenzylammonium (meth)acrylate, 2-(methacryloyloxy)ethyl trimethylammonium dimethylphosphate, 2-acrylamide-2-methylpropanesulfonic acid and 2-sulfoethyl(meth)acrylate.  
   
   
       3 . A pigment dispersing resin of  claim 1  wherein the ionic functional group-containing polymerizable unsaturated monomer (A) is selected from the group consisting of 2-(methacryloyloxy)ethyltrimethylammonium chloride and 2-acrylamide-2-methylpropanesulfonic acid.  
   
   
       4 . A pigment dispersing resin of  claim 1  wherein the ionic functional group-containing polymerizable unsaturated monomer (A) comprises a combination of quaternary ammonium salt group-containing polymerizable unsaturated monomer and tertiary amino group-containing polymerizable unsaturated monomer.  
   
   
       5 . A pigment dispersing resin of  claim 4  wherein tertiary amino group-containing polymerizable unsaturated monomer is selected from the group consisting of N,N-dialkylaminoalkyl (meth)acrylate and N,N-dialkylaminoalkyl (meth)acrylamide.  
   
   
       6 . A pigment dispersing resin of  claim 4  wherein the ionic functional group-containing polymerizable unsaturated monomer (A) comprises a combination of 2-(methacryloyloxy)ethyltrimethylammonium chloride and either N,N-dimethylaminoethyl (meth)acrylate or N,N-diethylaminoethyl (meth)acrylate.  
   
   
       7 . A pigment dispersing resin of  claim 1  wherein nonionic polymerizable unsaturated monomer (B) is compound of the following formula (1):  
     
       
         
         
             
             
         
       
       in which  
       R 1  stands for hydrogen or CH 3 ,  
       R 2  stands for hydrogen or alkyl group having one to four carbon atoms,  
       m is an integer of 4-60, and  
       n is an integer of 2 or 3,  
       and wherein oxyalkylene units (C n H 2n O) in the number of m may be the same or different from each other.  
     
   
   
       8 . A pigment dispersing resin of  claim 1  wherein nonionic polymerizable unsaturated monomer (B) is selected from the group consisting of polyethylene glycol (meth)acrylate and polypropylene glycol (meth) acrylate.  
   
   
       9 . A pigment dispersing resin of  claim 1  wherein other ethylenically unsaturated monomer (C) contains a hydroxyl group-containing polymerizable unsaturated monomer at least as a part of its component.  
   
   
       10 . A pigment dispersing resin of  claim 1  wherein other ethylenically unsaturated monomer (C) contains a carboxyl group-containing polymerizable unsaturated monomer at least as a part of its component.  
   
   
       11 . A pigment dispersing resin of  claim 1  wherein the copolymer has a weight average molecular weight within a range of 500 to 100,000.