Concentrated Dye Solution

1 . A concentrated storage-stable colour-stable aqueous liquid dye solution comprising

(i) at least one cationizable dye of the formula (I):

wherein B 1 and B 2 are independently —OH or NH 2 and D 3 =H or a radical of the formula

wherein

R 6 , R 7 , R 8 and R 9 are independently H or —SO 3 H and

M a and M b are independently selected from the group consisting of:

and

R a and R b are independently selected from the group consisting of:

wherein A − is a non-coloured anion which is the anion of an organic acid and/or the anion of an inorganic acid

(ii) an organic acid, an inorganic acid or a mixture thereof, and

(iii) water

wherein the concentrated storage-stable colour-stable aqueous liquid dye solution has an at most equimolar chloride ion fraction based on the dye present in the solution.

2 . A concentrated storage-stable colour-stable aqueous liquid dye solution according to claim 1 , wherein the pH is in the range of 2.0 to 4.0.

3 . A concentrated storage-stable colour-stable aqueous liquid dye solution according to claim 1 , wherein the solution further comprises a dye of the formula (II)

wherein

each A is independently —NH— or —O—,

B is a polyvalent group or atom,

n′ and n″ are natural numbers and the sum total of n′ and n″ is ≧2,

m is a natural number ≧0, and

CC is a group having the formula (c 1 ) or (c 2 )

wherein

each R 10 is independently H; C 1-4 alkyl; C 5-6 cycloalkyl; phenyl, benzyl or phenylethyl,

each R 10 ′ is independently H; —OH or C 1-4 alkyl

each T 1 is independently H; —CN; —COOR 15 ; CONR 16 R 17 ; SO 2 NR 16 R 17 ;

G is H; —R 11 NHR 12 or —R 11 NR 13 R 14 , wherein

R 11 is C 1-6 alkylene or C 2-6 alkenylene,

R 12 , R 13 , and R 14 are independently H; unsubstituted C 1-6 alkyl; C 2-6 alkyl substituted by OH, CN or halogen; phenyl-C 1-3 alkyl, where the phenyl radical is optionally singly, doubly or triply substituted by substituents selected from the group consisting of chlorine, C 1-4 alkyl and C 1-4 alkoxy; unsubstituted C 5-6 cycloalkyl or C 5-6 cycloalkyl singly, doubly or triply substituted by C 1-4 alkyl groups,

R 15 is C 1-6 alkyl radical or phenyl-C 1-3 alkyl radical,

R 16 and R 17 are independently H or a C 1-4 alkyl radical,

R 18 is in each occurrence independently H; C 1-4 alkyl radical; —NR 16 R 17 —(CH 2 ) 2-4 —NR 16 R 17 or —CONR 16 R 17 ,

R 19 is a C 1-4 alkyl radical or a hydroxy-C 1-4 alkyl radical,

R 20 is —S— or —O—,

R 21 is a hydrogen atom or a C 1-4 alkyl radical and

An − is a non-coloured anion,

with the proviso that

(i) the sum total of n′, n″ and m is less than the number of valences of B,

(ii) when the sum total of n′ and n″=2, then m is ≧1,

(iii) when the sum total of n′ and n″ 3 and A=NH, then m≧1, and/or a dye of the formula (III)

wherein

R 1 , R 2 or R 3 are independently H, CH 3 , C 2 H 5 , n-C 3 H 7 , i-C 3 H 7 , n-C 4 H 9 , i-C 4 H 9 , sec-C 4 H 9 ,

R n is —C 2 H 4 —, —C 3 H 6 —, —CH(CH3)CH 2 — or —C 4 H 6 —

Y is hydrogen or nitro, and

q is 1 or 2.

4 . A concentrated storage-stable colour-stable aqueous liquid dye solution according to claim 1 , wherein the concentrated storage-stable colour-stable aqueous liquid dye solution contains up to 40% by weight of dye, from 0.5% to 25% by weight of the organic acid and is made up to 100% by weight with water.

5 . A process for producing the concentrated storage-stable colour-stable aqueous liquid dye solution according to claim 1 , comprising the step of filtering an aqueous solution or suspension of at least one crude cationic dye of the formula (I) using a semipermeable membrane, by applying a pressure to remove salts and synthesis by-products having molecular weights below 500 and some water until the chloride ion fraction is at most equimolar with regard to the dye of the formula (I) and wherein the step of filtering forms a permeate.

6 . A process for producing the concentrated storage-stable colour-stable aqueous liquid dye solution according to claim 5 wherein the permeate is continuously or intermittently replaced or supplemented by water or buffer solution so that the dye concentration of the permeate does not change by more than 20%.

7 . A process for producing the concentrated storage-stable colour-stable aqueous liquid dye solution according to claim 5 , wherein the filtering step is done at a pH of between 5.5 and 6.5 and at a temperature of between 20 and 50 degrees Celsius.

8 . A process for producing the concentrated storage-stable colour-stable aqueous liquid dye solution according to claim 5 , further comprising the step of adjusting the pH to the range of 2.0 to 4.0.

9 . (canceled)

10 . A process for dyeing and/or printing a cellulosic material, comprising the step of contacting the cellulosic material with a concentrated storage-stable colour-stable aqueous liquid dye solution according to claim 1 .

11 . A process for producing an ink formulation for non-impact printing, comprising the step of mixing a concentrated storage-stable colour-stable aqueous liquid dye solution according to claim 1 with at least one other ink formulation compound.

12 . A substrate that has been dyed or printed with a concentrated storage-stable colour-stable aqueous liquid dye solution according to claim 1 .

13 . A process for producing the concentrated storage-stable colour-stable aqueous liquid dye solution according to claim 7 , wherein the filtering step is done at a pH of between 5.9 and 6.1.

14 . A process for producing the concentrated storage-stable colour-stable aqueous liquid dye solution according to claim 7 , wherein the filtering step is done at a temperature of between 30 and 35 degrees Celsius.

15 . A process according to claim 10 for dyeing and/or printing a cellulosic material, wherein the cellulosic material is selected from the group consisting of: paper, paperboard, card and wood.

16 . A process according to claim 11 wherein the ink formulation is for inkjet printing.

17 . A cellulosic material dyed and/or printed by a process according to claim 10 .

18 . An ink formulation produced by the process according to claim 11 .

19 . A concentrated storage-stable colour-stable aqueous liquid dye solution according to claim 1 , wherein the solution further comprises a dye of the formula (II)

wherein

each A is independently —NH— or —O—,

B is a polyvalent group or atom,

n′ and n″ are natural numbers and the sum total of n′ and n″ is ≧2,

m is a natural number ≧0, and

CC is a group having the formula (c 1 ) or (c 2 )

wherein

each R 10 is independently H; C 1-4 alkyl; C 5-6 cycloalkyl; phenyl, benzyl or phenylethyl,

each R 10 ′ is independently H; —OH or C 1-4 alkyl

each T 1 is independently H; —CN; —COOR 15 ; CONR 16 R 17 ; SO 2 NR 16 R 17 ;

G is H; —R 11 NHR 12 or —R 11 NR 13 R 14 , wherein

R 11 is C 1-6 alkylene or C 2-6 alkenylene,

R 12 , R 13 , and R 14 are independently H; unsubstituted C 1-6 alkyl; C 2-6 alkyl substituted by OH, CN or halogen; phenyl-C 1-3 alkyl, where the phenyl radical is optionally singly, doubly or triply substituted by substituents selected from the group consisting of chlorine, C 1-4 alkyl and C 1-4 alkoxy; unsubstituted C 5-6 cycloalkyl or C cycloalkyl singly, doubly or triply substituted by C 1-4 alkyl groups,

R 15 is C 1-6 alkyl radical or phenyl-C 1-3 alkyl radical,

R 16 and R 17 are independently H or a C 1-4 alkyl radical,

R 18 is in each occurrence independently H; C 1-4 alkyl radical; —NR 16 R 17 —(CH 2 ) 2-4 —NR 16 R 17 or —CONR 16 R 17 ,

R 19 is a C 1-4 alkyl radical or a hydroxy-C 1-4 alkyl radical,

R 20 is —S— or —O—,

R 21 is a hydrogen atom or a C 1-4 alkyl radical and

An − is a non-coloured anion,

with the proviso that

(i) the sum total of n′, n″ and m is less than the number of valences of B,

(ii) when the sum total of n′ and n″=2, then m is ≧1,

(iii) when the sum total of n′ and n″=3 and A=NH, then m≧1.

20 . A concentrated storage-stable colour-stable aqueous liquid dye solution according to claim 1 , wherein the solution further comprises a dye of the formula (III)

wherein

R 1 , R 2 or R 3 are independently H, CH 3 , C 2 H 5 , n-C 3 H 7 , i-C 3 H 7 , n-C 4 H 9 , i-C 4 H 9 , sec-C 4 H 9 ,

R n is —C 2 H 4 —, —C 3 H 6 —, —CH(CH3)CH 2 — or —C 4 H 6 —

Y is hydrogen or nitro, and

q is 1 or 2.