Pigment compositions with modified atrp copolymer dispersants

Abstract

The present invention relates to a composition containing modified block copolymer dispersants and dispersible inorganic or organic pigment. The block copolymers are prepared by atom transfer radical polymerization (ATRP) and modified with a salt forming group. The pigment composition is useful for preparing coating compositions, prints, images, inks or lacquers and other disperse systems.

1 . A composition comprising 
 a) 0.1-99.9% by weight dispersible inorganic or organic pigment particles; and    b) 0.1-99.9% by weight dispersing agents that essentially consist of a combination of 
 (i) a copolymer of the formula  
   {X-[(A x -B y )} p Y] q    (I),  
 wherein  
   X represents the fragment of a polymerisation initiator capable of initiating polymerisation of ethylenically unsaturated monomers by atom transfer radical polymerisation (ATRP) in the presence of a catalyst capable of activating controlled radical polymerisation by ATRP;    Y represents a polymer chain terminal group;    A and B represent polymer blocks composed of non-ionic repeating units of ethylenically unsaturated monomers; and wherein    at least one of the polymer blocks A or B or the chain terminal group Y additionally contains repeating units of ethylenically unsaturated monomers substituted with basic residues;    one of x and y represents zero, one or a numeral greater than one and the other one represents a numeral greater than one; and wherein    x and y defines the number of monomer repeating units in the polymer blocks A and B;    one of p and q represents one and the other one represents one or a numeral greater than one; and wherein    p defines the number of groups of the partial formula      X-(A x -B y )—  (A),    attached to the polymer chain terminal group Y; and    q defines the number of groups of the partial formula      -(A x -B y )—Y   (B),    per initiator fragment X; and    (ii) a salt forming compound selected from the group consisting of an organic acid, an alkylhalide group and a sulphonic acid ester or, in the alternative,    (i′) a copolymer (I), wherein 
 X, Y, A, B, x, y, p, and q are as defined above; and wherein  
 at least one of the polymer blocks A or B or the chain terminal group Y additionally contains repeating units of ethylenically unsaturated monomers substituted with acidic residues; and  
   (ii′) a salt forming compound substituted with basic residues;    with the proviso that p-toluenesulphonic acid is excluded as salt-forming component (ii).    
     
     
         2 . A composition according to  claim 1 , wherein the dispersible organic pigments or pearlescent flakes of component a) are selected from the azo pigment group consisting of azo, disazo, naphthol, benzimidazolone, azocondensation, metal complex, isoindolinone, and isoindoline pigments, the chinophthalon pigment, dioxazine pigment and the polycyclic pigment group consisting of indigo, thioindigo, quinacridones, phthalocyanines, perylenes, perionones, anthraquinones, anthrapyrimidines, indanthrones, flavanthrones, pyranthrones, anthantrones, isoviolanthrones, diketoypyrrolopyrrole, and carbazoles.-.  
     
     
         3 . A composition according to  claim 1 , wherein the dispersible inorganic pigment particles of component a) are selected from the group consisting of aluminum, aluminum oxide, silicon oxide and silicates, iron(III)oxide, chromium(III)oxide, titanium(IV)oxide, zirconium(IV)oxide, zinc oxide, zinc sulphide, zinc phosphate, mixed metal oxide phosphates, molybdenum sulphide, cadmium sulphide, carbon black or graphite, vanadates, chromates, and molybdates, and mixtures, crystal forms or modifications thereof.  
     
     
         4 . A composition according to  claim 1 , wherein 
 X represents a polymer chain terminal group from a polymerisation initiator which is selected from the group consisting of C 1 -C 8 alkyl halides, C 6 -C 15 aralkyl halides, C 2 -C 8 haloalkyl esters, arene sulphonyl halides, α-haloalkanenitriles, α-haloacrylates and halolactones;    Y represents a radically transferable group, hydrogen or a polymerisable chain terminal group and    p and q represent one.    
     
     
         5 . A composition according to  claim 1 , wherein 
 X represents a polymer chain terminal group from a polymerisation initiator which is selected from the group consisting of C 1 -C 8 alkyl halides, C 6 -C 15 aralkyl halides, C 2 -C 8 haloalkyl esters, arene sulphonyl halides, α-haloalkane nitriles and halolactones;    Y represents a saturated polymer chain terminal group;    p represents a numeral greater than one; and    q represents one.    
     
     
         6 . A composition according to  claim 1 , wherein one of the polymer blocks A and B is essentially composed of repeating units of ethylenically unsaturated monomers selected from the group consisting of styrenes, acrylic and C 1 -C 4 alkylacrylic acid-C 1 -C 24 alkyl esters, acrylic and C 1 -C 4 alkylacrylic acid-C 6 -C 11 aryl-C 1 -C 4 alkyl esters, acrylic and C 1 -C 4 alkylacrylic acid-C 6 -C 11 aryloxy-C 1 -C 4 alkyl esters, acrylic and C 1 -C 4 alkylacrylic acid-hydroxy-C 2 -C 6 alkyl esters, acrylic and C 1 -C 4 alkylacrylic acid-polyhydroxy-C 3 -C 6 alkyl esters, acrylic and C 1 -C 4 alkylacrylic acid-(C 1 -C 4 alkyl) 3 silyloxy-C 2 -C 4 alkyl esters; acrylic and C 1 -C 4 alkylacrylic acid-(C 1 -C 4 alkyl) 3 silyl-C 1 -C 4 alkyl esters, acrylic and C 1 -C 4 alkylacrylic acid-heterocyclyl-C 2 -C 4 alkyl esters; acrylic and C 1 -C 4 alkylacrylic acid esters having poly-C 2 -C 4 alkyleneglycol ester groups, wherein the ester groups may be substituted with C 1 -C 24 alkoxy groups, acrylic and methacrylic acid amides, acrylic and C 1 -C 4 alkylacrylic acid-(C 1 -C 4 alkyl) 1-2 amide, acrylonitrile, esters of maleic acid or fumaric acid, maleinimide and N-substituted maleinimides.  
     
     
         7 . A composition according to  claim 1 , wherein one of the polymer blocks A and B is essentially composed of repeating units of ethylenically unsaturated monomers selected from the group consisting of styrenes, acrylic and methacrylic acid-C 1 -C 24 alkyl esters, acrylic and methacrylic acid-hydroxy-C 2 -C 6 alkyl esters, acrylic and methacrylic acid-dihydroxy-C 3 -C 4 alkyl esters and acrylic and methacrylic acid esters having poly-C 2 -C 4 alkyleneglycol ester groups, wherein the ester groups may be substituted with C 1 -C 24 alkoxy groups.  
     
     
         8 . A composition according to  claim 1 , wherein the repeating unit of an ethylenically unsaturated monomer substituted with basic residues present in at least one of the polymer blocks A and B or the chain terminal group Y is represented by a compound of the formula  
         CH 2 ═C(—R 1 )—C(═O)—R 2    (III),  
       wherein 
 R 1  represents hydrogen or C 1 -C 4 alkyl; and  
 R 2  represents a basic substituent selected from the group consisting of amino-C 2 -C 18 alkoxy, C 1 -C 4 alkylamino-C 2 -C 18 alkoxy, di-C 1 -C 4 alkylamino-C 2 -C 18 alkoxy, hydroxy-C 2 -C 4 alkylamino-C 2 -C 18 alkoxy and C 1 -C 4 alkyl-(hydroxy-C 2 -C 4 alkyl)amino-C 2 -C 18 alkoxy; or wherein  
 the ethylenically unsaturated monomer substituted with a basic group present in one of the polymer blocks A and B or the chain terminal group Y is an amino monomer selected from the group consisting of amino substituted styrene, (C 1 -C 4 alkyl) 1 2 amino substituted styrene, N-mono-(C 1 -C 4 alkyl) 1-2 amino-C 2 -C 4 alkyl(meth)acrylamide and N,N-di-(C 1 -C 4 alkyl) 1-2 amino-C 2 -C 4 alkyl(meth)acrylamide, vinylpyridine or C 1 -C 4 alkyl substituted vinylpyridine, vinylimidazole and C 1 -C 4 alkyl substituted vinylimidazole.  
 
     
     
         9 . A composition according to  claim 8 , wherein the repeating unit of an ethylenically unsaturated monomer substituted with a basic group present in one of the polymer blocks A and B is represented by a compound of the formula (III), wherein 
 R 1  represents hydrogen or methyl; and    R 2  represents amino substituted C 2 -C 18 alkoxy selected from the group consisting of amino-C 2 -C 4 alkoxy, C 1 -C 4 alkylamino-C 2 -C 4 alkoxy, di-C 1 -C 4 alkylamino-C 2 -C 4 alkoxy, hydroxyC 2 -C 4 alkylamino-C 2 -C 18 alkoxy and C 1 -C 4 alkyl-(hydroxy-C 2 -C 4 alkyl)amino-C 2 -C 4 alkoxy;    or is amino substituted styrene, (C 1 -C 4 alkyl) 1-2 amino substituted styrene, and N,N-di-(C 1 -C 4 alkyl) 2 amino-C 2 -C 4 alkyl(meth)acrylamide.    
     
     
         10 . A composition according to  claim 1 , wherein the repeating unit of an ethylenically unsaturated monomer substituted with basic residues present in at least one of the polymer blocks A and B or the chain terminal group Y is selected from the group consisting of 4-aminostyrene, 4-dimethylaminostyrene, 2-dimethylaminoethylacrylate (DMAEA), 2-dimethylaminoethyl methacrylate (DMAEMA), 2-diethylaminoethyl acrylate (DEAEA), 2-diethylaminoethyl methacrylate (DEAEMA), 2-t-butylamino ethylacrylate (t-BAEA), 2-t-butylaminoethyl methacrylate (t-BAEMA), 3-dimethylaminopropylmethacrylamide 3-dimethylaminopropylmethacrylamide, 4-vinylpyridine, 2-vinylpyridine and 1-vinylimidazole.  
     
     
         11 . A composition according to  claim 1 , wherein the polymer chain terminal group Y represents a radically transferable group, hydrogen, a polymerisable chain terminal group or a saturated polymer chain terminal group, which is formed by polymerisation or copolymerisation of a polymerisable chain terminal group.  
     
     
         12 . A composition according to  claim 1 , wherein the component (ii) forms a salt with the copolymer (I) by acid-base reaction, acid addition or quaternisation reaction.  
     
     
         13 . A composition according to  claim 12 , wherein a sulpho, carboxy or phosphono group, a sulphonic acid-C 1 -C 4 alkyl ester group or an C 1 -C 8 alkyl halide group, which is present in the salt forming compound (ii), forms a salt by reaction with a free amino group or a primary, secondary or tertiary amino group which is present in at least one of the polymer blocks A and B or the chain terminal group Y of the copolymer component (i).  
     
     
         14 . A composition according to  claim 12 , wherein the salt forming compound (ii) is selected from the group consisting of monocyclic or polycyclic sulphonic, mono- or polycyclic carboxylic or phosphonic acids, aliphatic sulphonic, carboxylic or phosphonic acids substituted with mono- or polycyclic groups, C 1 -C 8 alkyl halides substituted with mono- or polycyclic groups and C 1 -C 4 alkyl esters of mono- or polycyclic sulphonic acids, with the proviso that p-toluenesulphonic acid is excluded.  
     
     
         15 . A composition according to  claim 12 , wherein the salt forming compound (ii) is selected from the group consisting of polycyclic sulphonic, mono- or polycyclic carboxylic or phosphonic acids, aliphatic sulphonic, carboxylic or phosphonic acids substituted with mono- or polycyclic groups, C 1 -C 8 alkyl halides substituted with mono- or polycyclic groups and C 1 -C 4 alkyl esters of mono- or polycyclic sulphonic acids.  
     
     
         16 . A composition according to  claim 1 , which additionally contains binding agents and conventional additives selected from the group consisting of surfactants, light stabilisers, UV-absorbers, anti-foaming agents, antioxidants, dyes, plasticisers, thixotropic agents, drying catalysts, anti-skinning agents and levelling agents.  
     
     
         17 . A pigment dispersion comprising 
 a′) dispersed pigment particles; and    b′) a combination of a copolymer (I) wherein X, A, B, Y, x, y, p and q are as defined in  claim 1;  and a salt forming compound (ii) or (ii′) as defined in  claim 1;  
 and a carrier liquid.  
   
     
     
         18 . A process for preparing the pigment dispersion according to  claim 17 , which comprises preparing the copolymer (I) by copolymerising the fragments A and B by ATRP and optionally replacing or polymerising the chain terminal group Y; and 
 α) modifying the copolymer with the salt forming compound, isolating and adding the modified block copolymer to dispersible pigment particles and optionally binder materials, fillers or other conventional additives; or    β) modifying the copolymer with the salt forming compound in the presence of dispersible pigment particles and optionally binder materials, fillers or other conventional additives.    
     
     
         19 . A process according  claim 18  comprising the additional step of isolating the pigment and the modified copolymer and optionally other conventional additives in a solid product form essentially free from liquid carrier medium.  
     
     
         20 . A method of preparing coating compositions, prints, images, inks, lacquers, pigmented plastics, adhesives, casting resins, filled composites, glass fibre reinforced composites, laminates, cement based construction materials like plaster and tile adhesives which comprises adding the pigment dispersion according to  claim 17  thereto.