Non-metal tanning process

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 at least a mixture of compounds of formula (I) and formula (II),

wherein

Hal is fluorine or chlorine,

R1 is hydrogen, C 1-8 -alkyl or an alkyleneoxy radical of formula (III),

—(—C 2-3 alkylene—O—) q —H  (III)

R2 is

a) phenyl, mono- or di-substituted with SO 3 M or COOM and optionally substituted also with hydroxyl or C 1-4 -alkyl or C 1-4 -alkoxy, or

b) naphthyl, mono- or di- or tri-substituted with SO 3 M and optionally substituted also with hydroxyl, or

c) C 1-8 -alkylene, substituted with (SO 3 M) or (COOM), or

d) a radical of formula (IV),

—(—C 2-3 alkylene—O—) p —Y  (IV)

e) or a radical of formula (IVa),

—(C 2-3 alkylene—O) p —C 2-3 alkylene-SO 2 CH 2 CH 2 O—Y  (IVa)

m is 1 or 2,

p is 0 or 1,

Y is hydrogen or —SO 3 M,

q is of from 1 to 10,

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

R3 is hydrogen or chlorine,

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

2. A 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 pickled and subsequently depickled to a pH in the range of 6 to 10 before tanning with (A).

4. A process according to claim 1 , wherein the tanning agent (A) is 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 (C 1 ) or a mixture thereof 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 aqueous composition (T 1 ) comprises a thickener (E).

8. A process according to claim 1 , wherein the tanning bath 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 or 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 or 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, and

mixtures thereof.

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

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) comprising at least a mixture of compounds of formula (I) and formula (II),

wherein

Hal is fluorine or chlorine,

R1 is hydrogen, C 1-8 -alkyl or an alkyleneoxy radical of formula (III),

—(—C 2-3 alkylene-O—) g —H  (III)

R2 is

a) phenyl, mono- or di-substituted with SO 3 M or COOM and optionally substituted also with hydroxyl or C 1-4 -alkyl or C 1-4 -alkoxy, or

b) naphthyl, mono- or di- or tri-substituted with SO 3 M and optionally substituted also with hydroxyl, or

c) C 1-8 -alkylene, substituted with (SO 3 M) or (COOM), or

d) a radical of formula (IV),

—(—C 2-3 alkylene-O—) p —Y  (IV)

e) or a radical of formula (IVa),

—(C 2-3 alkylene-O) p —C 2-3 alkylene-SO 2 CH 2 CH 2 O—Y  (IVa)

m is 1 or 2,

p is 0 or 1,

Y is hydrogen or —SO 3 M,

q is of from 1 to 10,

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

R3 is hydrogen or chlorine.

15. A process as defined in claim 1 , further comprising at least one further treatment selected from the group consisting of

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

(b) fat-liquoring,

(c) dyeing, and

(d) finishing.

16. A process as defined in claim 1 , further comprising retanning with a non-mineral tanning agent (F).

17. A process in accordance with claim 1 , comprising retanning with non-mineral tanning agent (F), fat-liquoring and optionally dyeing, finishing or a mixture thereof.

18. A tanned leather, skin or pelt made by the process according to claim 1 .