Non metal tanning

1. A process for the production of tanned leather, skin or pelt by non-metal tanning, comprising the step of tanning a bated hide, skin or pelt with a tanning agent (A), the tanning agent (A) being a sulpho-group-containing dichloro-diazine selected from the group of consisting of compounds of formula (I)

of formula (II)

of formula (III)

and mixtures thereof,

wherein

R1 is hydrogen, methyl, methoxy, benzoyl, naphthoyl, mono- or di(C 1-4 -alkyl)-aminocarbonyl, C 1-8 alkoxy-carbonyl or oxy-mono- or oligo-(C 2-3 -alkyleneoxy)-carbonyl

R2-(SO 3 M) n is a radical of formula

R3 is hydrogen, C 1-8 -alkyl or C 1-8 -alkoxy,

m is 1 or 2,

n is 1 or 2

and

M is hydrogen, an alkali metal cation or an ammonium cation, the ammonium cation being a protonated tertiary amine or a quaternary ammonium cation,

in a tanning bath, the tanning bath having a pH of from 6 to 10 at the beginning of tanning step.

2. A tanning process according to claim 1 , wherein the bated hide or skin or pelt is subjected to tanning with (A) without previous pickling.

3. A process according to claim 1 , wherein a bated and pickled hide, skin or pelt is depickled to a pH in the range of 6 to 10 before the tanning step.

4. A process according to claim 1 , wherein the tanning agent (A) is employed in the form of an aqueous composition (T) free of metal compounds of tanning activity.

5. A process according to claim 4 , wherein the composition (T) is a composition (T1), the composition (T1) further comprising a surfactant (B) a buffer (C1) or both to keep an acidic to neutral pH.

6. A process according to claim 5 , wherein the composition (T1) further comprises an agent (D) to protect against the damaging action of microorganisms a polysaccharide-based thickener (E) or a mixture thereof.

7. A process according to claim 6 , wherein the aqueous composition (T1) comprises a thickener (E).

8. A process according to claim 1 , wherein the tanning bath further comprises a buffer (C2) to achieve a nearly neutral to basic pH at the beginning of the tanning step.

9. A process according to claim 1 , wherein the tanning step with the tanning agent (A) is a pre-tanning, a main tanning, a full tanning or a pretanning and a main tanning.

10. A process according to claim 9 , wherein a non-mineral tanning agent (F), which is different from the tanning agent (A), is used before, after or together with tanning agent (A) in pre-tanning, in main tanning, in full tanning, or in combination with tanning agent (A) in full tanning.

11. A process according to claim 10 , wherein the non-mineral tanning agent (F) is selected from the group consisting of

(F1) a vegetable tanning agent,

(F2) a syntan,

(F3) a synthetic, semisynthetic or natural resin or polymer,

(F4) a tanning natural oil or modified oil,

(F5) a 4,6-dichloro-1,3,5-triazin-2-yl-aminobenzene-mono- or di-sulphonic acid salt and

(F6) a tanning oxazolidine.

12. A process according to claim 9 , wherein the skin hide or pelt is tanned with tanning agent (A) in a main or full tanning and then are subjected to a complementary tanning with a non-mineral tanning agent (F) which is different than tanning agent (A).

13. A process according to claim 10 , wherein the non-mineral tanning agent (F) is employed in a smaller amount compared with the amount of the tanning agent (A).

14. A tanning agent (A) for a tanning process comprising a tanning agent (A), the tanning agent (A) being a sulpho-group-containing dichloro-diazine selected from the group of consisting of compounds of formula (I)

of formula (II)

of formula (III)

and mixtures thereof,

wherein

R1 is hydrogen, methyl, methoxy, benzoyl, naphthoyl, mono- or di(C 1-4 -alkyl)-aminocarbonyl, C 1-8 -alkoxy-carbonyl or oxy-mono- or oligo-(C 2-3 -alkyleneoxy)-carbonyl

R2-(SO 3 M) n is a radical of formula

R3 is hydrogen, C 1-8 -alkyl or C 1-8 -alkoxy,

m is 1 or 2,

n is 1 or 2

and

M is hydrogen, an alkali metal cation or an ammonium cation, the ammonium cation being a protonated tertiary amine or a quaternary ammonium cation.

15. A process according to claim 1 , further comprising at least one further treatment selected from the group consisting of

(a) retanning with a non-mineral tanning agent (F), which is different from the tanning agent (A),

(b) fat-liquoring,

(c) dyeing, and

(d) finishing.

16. A process according to claim 1 , further comprising a further treatment comprising retanning with a non-mineral tanning agent (F) which is different than tanning agent (A).

17. A process according to claim 1 , further comprising a further treatment comprising retanning with a non-mineral tanning agent (F) which is different than tanning agent (A), fat-liquoring and optionally dyeing finishing or both.

18. Tanned leather, skin or pelt made by a process according to claim 1 .