Novel triphenylmethane dyes for water-based compositions

Abstract

Novel pigment compositions comprising pigmentary salts and polymers are provided. Pigmentary salts of triphenylmethane dyes are co-precipitated with polyfunctional polymeric acids to form pigment compositions having greatly increased hydrophilicity, dispersability and compatibility with water/polymeric dye vehicles. Processes for forming these pigment compositions are also provided.

We claim:  
     
         1 . A composition comprising pigment particles comprising at least one salt of a dye and inclusions of an water-dispersible or water-soluble polymer.  
     
     
         2 . The composition of  claim 1 , wherein the dye is a triphenylmethane dye.  
     
     
         3 . The composition of  claim 2 , wherein the triphenylmethane dye comprises triphenylpararosaniline.  
     
     
         4 . The composition of  claim 1 , wherein the polymer is an acid-functional polymer.  
     
     
         5 . The composition of  claim 4 , wherein the acid-functional polymer is a poly(styrene-acrylic acid) copolymer.  
     
     
         6 . The composition of  claim 5 , wherein the poly(styrene-acrylic acid) copolymer comprises styrene and acrylic monomer units in a mole ratio of from about 1:4 to about 4:1.  
     
     
         7 . A process of preparing a composition, comprising the steps of: 
 a) providing an aqueous solution comprising at least one triphenylmethane dye and at least one aqueous acid;    b) heating the solution;    c) dispersing or dissolving an anionic polymer; and    d) coprecipitating out the dye and the polymer.    
     
     
         8 . The process of  claim 7 , wherein the triphenylmethane dye comprises triphenylpararosaniline.  
     
     
         9 . The process of  claim 7 , wherein the aqueous acid is selected from the group consisting of phosphoric acid, sulfuric acid, acetic acid, propionic acid, acrylic acid, HBr, HCI, HF, HI, RCO 2 H, wherein R is a lower molecular weight alkyl having from one carbon to about five carbons and R′CO 2 H, wherein R′ is a phenyl.  
     
     
         10 . The process of  claim 7 , wherein the aqueous acid is selected from the group consisting of phosphoric acid, sulfuric acid, acetic acid, propionic acid and acrylic acid.  
     
     
         11 . The process of  claim 7 , wherein the solution is heated to a temperature of at least 100° C.  
     
     
         12 . The process of  claim 7 , wherein the anionic polymer is an acid functional polymer.  
     
     
         13 . The process of  claim 12 , wherein the acid functional polymer is a poly(styrene-acrylic acid) copolymer.  
     
     
         14 . The process of  claim 13 , wherein the poly(styrene-acrylic acid) copolymer comprises styrene and acrylic monomer units in a mole ratio of from about 1:4 to about 4:1.  
     
     
         15 . The process of  claim 7 , further comprising cooling the heated solution.  
     
     
         16 . The process of  claim 15 , wherein the heated solution is cooled to less than about 60° C.  
     
     
         17 . The process of  claim 7 , wherein the dye and polymer are coprecipitated out by increasing the pH.  
     
     
         18 . The process of  claim 17 , wherein the pH of the solution is increased to from about pH 3 to about pH 11.  
     
     
         19 . The process of  claim 17 , wherein the pH of the solution is increased to from about pH 4.0 to about pH 6.0.  
     
     
         20 . The process of  claim 17 ,wherein the pH is increased by the addition of aqueous ammonia.  
     
     
         21 . A pigment composition prepared according to the process of  claim 7.