Pigment compositions and process of shading

Abstract

Compositions comprising a) a mixture of i) C.1. Pigment Violet 19 together with either C.I. Pigment Blue 15 or C.I. Pigment Blue 60, or ii) C.I. Pigment Red 177 together with either C.I. Pigment Blue 15 or C.I. Pigment Blue 60, and b) a dispersant, c) optionally a biocide, and d) water. A process for shading of paper using said compositions or by applying separate pigment dispersions of a) C.I. Pigment Violet 19 and either C.I. Pigment Blue 15 or C.I. Pigment Blue 60, or b) C.I. Pigment Red 177 and either C.I. Pigment Blue 15 or C.I. Pigment Blue 60.

1 . A composition comprising 
 a) a mixture of C.I. Pigment Violet 19 together with either C.I. Pigment Blue 15 or C.I. Pigment blue 60,    b) a dispersant,    c) optionally a biocide, and    d) water.    
     
     
         2 . A composition according to  claim 1  wherein component a) comprises a mixture of C.I. Pigment Violet 19 together with C.I. Pigment Blue 15, in which mixture the amount by weight of C.I. Pigment Violet 19 is greater than 50%, based on the weight of the mixture of pigments.  
     
     
         3 . A composition according to  claim 1  or  claim 2 , wherein the mixture of pigments contains 60% to 95% by weight of C.I. Pigment Violet 19.  
     
     
         4 . A composition according to any one of  claims 1  to  3 , wherein the mixture of pigments contains 70% to 90% by weight of C.I. Pigment Violet 19.  
     
     
         5 . A composition according to any one of  claims 1  to  4 , wherein the mixture of pigments contains 75% to 85% by weight of C.I. Pigment Violet 19 and 15% to 25% by weight of C.I. Pigment Blue 15.  
     
     
         6 . A composition according to  claim 1  wherein component a) comprises a mixture of C.I. Pigment Violet 19 together with C.I. Pigment Blue 15 or C.I. Pigment Blue 60, in which mixture the amount by weight of C.I. Pigment Violet 19 is less than 50%, based on the weight of the mixture of pigments,  
     
     
         7 . A composition according to  claim 6 , wherein the mixture of pigments contains C.I. Pigment Violet 19 together with C.I. Pigment Blue 60.  
     
     
         8 . A composition according to  claim 6  or  claim 7 , wherein the mixture of pigments contains 30% to less than 50% by weight of C.I. Pigment Violet 19.  
     
     
         9 . A composition according to any one of  claim 6  to  claim 8 , wherein the mixture of pigments contains 40% to less than 50% by weight of C.I. Pigment Violet 19.  
     
     
         10 . A composition comprising 
 a) a mixture of C.I. Pigment Red 177 together with C.I. Pigment Blue 15 or C.I. Pigment Blue 60,    b) a dispersant,    c) optionally a biocide, and    d) water.    
     
     
         11 . A composition according to  claim 10 , wherein the mixture of pigments contains C.I. Pigment Red 177 together with C.I. Pigment Blue 60.  
     
     
         12 . A composition according to  claim 10  or  claim 11 , wherein the mixture of pigments contains below 60% by weight of C.I. Pigment Red 177.  
     
     
         13 . A composition according to any one of  claims 10  to  12 , wherein the mixture of pigments contains below 50% by weight of C.I. Pigment Red 177.  
     
     
         14 . A composition according to any one of  claims 5  to  8 , wherein the mixture of pigments contains 20 to 40% by weight of C.I. Pigment Red 177 and 60 to 75% by weight of C.I. Pigment Blue 60.  
     
     
         15 . A composition according to any one of  claims 1  to  14 , which contains 0.1 to 40%, more preferably 10 to 30%, most preferably around 20% pigment, based on the weight of the dispersion.  
     
     
         16 . A composition according to any one of  claims 1  to  15 , which contains 0.1 to 30%, preferably 0.1 to 8% of dispersant, by weight of the composition.  
     
     
         17 . A composition according to any one of  claims 1  to  16 , which contains a biocide.  
     
     
         18 . A composition according to any one of  claims 1  to  17 , wherein the dispersant is polyacrylic acid, polymethacrylic acid, polymaleic anhydride, polyurethane, polyvinylether, polyvinylalcohol, polyalkylene glycol, polyethylene oxide, cellulose derivatives, polyimine, polyvinylpyridine, or copolymers thereof, or copolymers of acrylic acid with styrene, acrylonitrile, vinylacetate, vinylphosphonate, vinylpropionate, vinylchloride, itaconic acid or maleic anhydride, or ethoxylated or propoxylated fatty, ethoxylated or propoxylated fatty quaternary salts, ethoxylated fatty amides, alkyl-, cycloalkyl- or alkylaryl-oxypoly(ethylenoxy)ethanol, cycloalkyloxypoly(ethylenoxy)laurate or oleate, polyethylene glycol 400 laurate or oleate, alkyl-, cycloalkyl- or alkylaryl-poly(ethylenoxy)carboxylate or phosphonate or aromatic sulphonic acid polymer with formaldehyde or salts thereof.  
     
     
         19 . A process for shading of paper to be used for food packaging material, which process comprises applying to at least one stage of the paper making process either 
 a) a composition according to  claim 1 ,    b) a composition according to  claim 10 ,    c) an aqueous dispersion of C.I. Pigment Violet 19 and an aqueous dispersion of C.I. Pigment Blue 15, wherein amount of C.I. Pigment Violet 19, or    d) an aqueous dispersion of C.I. Pigment Red 177 and an aqueous dispersion of either C.I. Pigment Blue 15 or C.I. Pigment Blue 60.    
     
     
         20 . A process according to  claim 19 , wherein the composition is added to the mixing chest, the thin stock, the thick stock or preferably to the pulp.  
     
     
         21 . A process according to  claim 19  or  claim 20 , wherein the composition is added in an amount of 5 to 1000 g per tonne, preferably in an amount of 10 to 400 g/tonne and most preferably in an amount of 50 to 400 g/tonne.  
     
     
         22 . A process according to any one of  claims 19  to  21 , wherein in addition a cationic coagulant or retention aid is added.  
     
     
         23 . A process according to  claim 22 , wherein the cationic coagulant is added to the thick stock, preferably prior to dilution.  
     
     
         24 . A process according to  claim 23 , wherein the cationic coagulant is added in an amount of 10 to 1000 g per tonne, preferably in an amount of 50 to 700 g/tonne and most preferably in an amount of 100 to 500 g/tonne.  
     
     
         25 . Use of a composition according to  claim 1  or  claim 10  for shading of paper to be used for food packaging material.