Use of reactive cross-linking agents for protein-containing substrates and processes for tanning and dyeing of leather

1. A reactive colourless protein cross-linking agent for the cross-linking of protein-based substrates having amine and optionally OH functionality, said cross-linking agent comprising a compound according to formula [1]:

wherein

L 1 and L 5 are each independently from each other selected from H or C 1 -C 4 alkyl, and

L 2 , L 3 , L 4 , L 6 , L 7 and L 8 are each independently from each other selected from H, C 1 -C 4 alkyl, SO 3 H, and OL 22 wherein L 22 is selected from H and C 1 -C 4 alkyl, and

X is selected from Cl, F and nicotinic acid, and

K 1 , K 2 , K 3 and K 4 are each independently from each other selected from —H and protein reactive radicals, and

wherein the protein-based substrates are selected from collagen containing fibrous material, gelatin, fibroin, elastin and soy (soyabean).

2. The reactive colourless protein cross-linking agent according to claim 1 , wherein the protein reactive radicals are selected from

—SO 2 —Y,

—NH—(CH 2 ) 2-3 —SO 2 —Y,

—NH—CO—(CH 2 ) 2-3 —SO 2 —Y,

—NH—(CH 2 ) 2 —O—(CH 2 ) 2 —SO 2 —Y,

—NH—CO—CHW—CH 2 —W, and

—NH—CO—C(W)═CH 2

wherein Y is selected from —CH 2 —CH 2 —U and —CH═CH 2 , and U and W are independently from each other a group removable under alkaline conditions.

3. The reactive colourless protein cross-linking agent according to claim 2 , wherein U and W are independently from each other selected from

—Cl, —Br, or —F,

—OSO 3 H,

—SO 3 H,

—OCO—CH 3 ,

—OPO 3 H 2 ,

—OCO—C 6 H 5 ,

—OSO 2 -C 1 -C 4 alkyl, and

—OSO 2 N(C 1 -C 4 alkyl) 2 .

4. The reactive colourless protein cross-linking agent according to claim 3 , wherein U and W are independently from each other selected from —Cl, —OSO 3 H, —SO 3 H, —OCO—CH 3 , —OCO—C 6 H 5 and —OPO 3 H 2 .

5. The reactive colourless protein cross-linking agent according to claim 1 , wherein K 1 , K 2 , K 3 and K 4 are each independently from each other selected from H, SO 2 —CH═CH 2 and —SO 2 —CH 2 —CH 2 —U and wherein U is a group removable under alkaline conditions.

6. The reactive colourless protein cross-linking agent according to claim 1 , wherein the cross-linking agent is selected from compounds according to formula [2], [3], [4], [5], [6], [7], [8], [9] and [10]:

7. A composition comprising the reactive colourless protein cross-linking agent according to claim 1 and at least one dye.

8. The composition according to claim 7 , wherein the dye is a reactive dye comprising a mono, bi, tri and/or poly functional reactive dye having at least one protein reactive radical.

9. The composition according to claim 8 , wherein the at least one reactive dye is selected from compounds according to formula [20] and [21]

wherein

A 1 , A 2 and A 3 are each independently of the others a radical of a monoazo, polyazo, metal-complexed azo, anthraquinone, phthalocyanine, formazan or dioxazine chromophore having at least one sulfo group,

B is an organic bridge member,

Q 1 , Q2, Q3 and Q4 are each independently of the others hydrogen or unsubstituted or substituted C 1 -C 4 alkyl,

G 1 and G2 are halogen, 3-carboxypyridin-1-yl or 3-carbamoylpyridin-1-yl,

(Z 1 ) 2-3 is 2 to 3 identical or different protein reactive radicals,

Z 2 and Z 3 are each independently of the other identical or different protein reactive radicals, and

b is the number 0 or 1.

10. The composition according to claim 9 , wherein the protein reactive radicals Z 1 , Z 2 and Z 3 are each independently of the others a radical of the formula

—SO 2 —Y  (3a),

—NH—CO—(CH 2 ) l —SO 2 —Y  (3b),

—CONR 2 —(CH 2 ) m —SO 2 —Y  (3c),

—NH—CO—CH(Hal)—CH 2 —Hal  (3d),

—NH—CO—C(Hal)═CH 2   (3e),

wherein

Hal is chlorine or bromine;

X 1 is halogen, 3-carboxypyridin-1-yl or 3-carbamoylpyridin-1-yl;

T 1 independently has the meaning of X 1 , or is a substituent which is not protein reactive, or is a protein reactive radical of the formula:

wherein

R 1 , R 1a and R 1b independently of one another are each hydrogen or C 1 -C 4 alkyl,

R 2 is hydrogen, C 1 -C 4 alkyl which is unsubstituted or substituted by hydroxyl, sulfo, sulfato, carboxyl or cyano or a radical

R 3 is hydrogen, hydroxyl, sulfo, sulfato, carboxyl, cyano, halogen, C 1 -C 4 alkoxycarbonyl, C 1 -C 4 alkanoyloxy, carbamoyl or the group —SO 2 —Y,

alk and alk 1 independently of one another are linear or branched C 1 -C 6 alkylene,

arylene is a phenylene or naphthylene radical which is unsubstituted or substituted by sulfo, carboxyl, C 1 -C 4 alkyl, C 1 -C 4 alkoxy or halogen,

Q is a radical —O— or —NR 1 —, in which R 1 is as defined above,

W is a group —SO 2 —NR 2 —, —CONR 2 — or —NR 2 CO—, in which R 2 is as defined above,

Y is vinyl or a radical —CH 2 —CH 2 —U and U is a group which can be split off under alkaline conditions,

Y 1 is a group —CH(Hal)—CH 2 —Hal or —C(Hal)═CH 2 and Hal is chlorine or bromine and

l and m independently of one another are an integer from 1 to 6 and n is the number 0 or 1;

and

X 2 is halogen or C 1 -C 4 alkylsulfonyl;

X 3 is halogen or C 1 -C 4 alkyl; and

T 2 is hydrogen, cyano or halogen.

11. The composition according to claim 7 , wherein the dye is an acid dye comprising acidic groups.

12. A process for cross-linking a protein-based substrate having amine and optionally OH functionality, said process comprising:

placing the protein-based substrate in a liquid medium, in a processing vessel, at temperature in the range 10° C. to 50° C.,

adding the reactive cross-linking agent according to claim 1 to the liquid medium in an amount in the range between 1 wt % and 40 wt % based on the dry weight of the protein-based substrate,

letting the reactive cross-linking agent penetrate for a period of time into the protein-based substrate,

adjusting the pH of the liquid medium in order for the cross-linking agent to react with the protein reactive groups in the protein-based substrate to complete the cross-linking reaction, and

rinsing/washing of the cross-linked substrate.

13. A process for simultaneously cross-linking and dyeing a protein-based substrate having amine and optionally OH functionality, said process comprising:

placing the protein-based substrate in a liquid medium, in a processing vessel, at temperature in the range 10° C. to 50° C.,

adding the reactive cross-linking agent according to claim 1 and a reactive dye to the aqueous liquid in an amount such that the amount of cross-linking agent is 1 wt % to 39 wt % and the amount of reactive dye is 1 wt % to 39 wt % based on the dry weight of the protein-based substrate,

letting the reactive cross-linking agent and reactive dye penetrate for a period of time into the protein-based substrate,

adjusting the pH of the liquid medium in order for the reactive cross-linking agent and reactive dye to react with the protein reactive groups in the protein-based substrate to complete the cross-linking and dyeing reaction, and

rinsing/washing of the cross-linked and dyed substrate.

14. A cross-linked protein-based substrate obtained by the process according to claim 12 .

15. A cross-linked and dyed protein-based substrate obtained by the process according to claim 13 .

16. The cross-linked and dyed protein-based substrate according to claim 14 , wherein the substrate is selected from collagen containing fibrous material, gelatin, fibroin, elastin and soy (soyabean).

17. The cross-linked and dyed protein-based substrate according to claim 15 , wherein the substrate is selected from collagen containing fibrous material, gelatin, fibroin, elastin and soy (soyabean).