PROCESS FOR LIMING OF HIDES, SKINS OR PELTS

Abstract

The present invention relates to a novel process for liming of skins/hides/pelts using a quaternary ammonium salt as anti-wrinkle agent.

Claims

1. A process for liming of hides, skins or pelts comprising treating the hides, skins or pelts with an anti-wrinkle agent composition comprising a quaternary ammonium salt.

2. Process according to claim 1, wherein the quaternary ammonium salt is represented by the formula X.sup.()N.sup.(+)R.sub.1R.sub.2R.sub.3R.sub.4 moiety, wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are the same or different alkyl or aryl groups, wherein X.sup.() is a negative counterion present when none of R.sub.1, R.sub.2, R.sub.3 and R.sub.4 is an internal counterion.

3. Process according to claim 2, wherein R.sub.1 and R.sub.2 are both alkyl groups having 1 to 4 carbon atoms.

4. Process according to claim 1, wherein the quaternary ammonium salt anti-wrinkle agent is selected from the group consisting of a salt of 2-hydroxy-N,N,N-trimethyl-ethanaminium (choline), 1-carboxy-N,N,N-trimethyl-methanaminium (trimethylglycine), 3-carboxy-2-hydroxy-N,N,N-trimethyl-1-propanaminium (carnitine), a salt of N,N,N-tributyl-1-butanaminium (tetrabutylammonium), a salt of N-alkyl-N,N-dimethyl-benzenemethanaminium, and any mixture thereof.

5. Process according to claim 1, wherein X.sup.() is a halide, when the quaternary ammonium salt is not an internal salt.

6. Process according to claim 1, wherein the anti-wrinkle agent composition further comprises another anti-wrinkle agent different from said quaternary ammonium salt.

7. Process according to claim 1, wherein the anti-wrinkle agent composition is an aqueous solution.

8. Process according to claim 1, wherein the quaternary ammonium salt has a concentration between 30 and 80 weight % based on a total weight of anti-wrinkle agent composition as 100%.

9. Process according to claim 1, wherein the total amount of anti-wrinkle agent composition is between 0.50 weight % and 2.0 weight %, based on a weight of the hide, skin or pelt as 100%.

10. Process according to claim 1, wherein the anti-wrinkle composition further contains one or more surfactants, biocides and/or unhairing agents.

11. Process according to claim 1, comprising: i) treating washed skins, hides or pelts in a drum with a solution comprising 30-100% of water together with 0.50-500% of lime and 0.50-2.00% of an anti-wrinkle agent composition comprising a quaternary ammonium salt for a duration of between 10 and 120 minutes; ii) adding unhairing agents and an additional 0.30-2.00% of lime to the solution and dehairing at a pH maintained above 12 for a duration of between 30 and 90 minutes; iii) running the drum for a duration of between 30 and 240 minutes to achieve 90-100% penetration of the lime as determined by a change of pH to below 8 inside 90-100% of the volume of the skin, hide or pelt; (iv) adding 50-150% of water together with 0.3-2.0% of lime and performing several cycles of running the drum and resting, followed by draining the drum.

12. A limed hides, skins or pelts obtainable by the process according to claim 1.

13. Process according to claim 2, wherein said alkyl or aryl groups contains 1 to 18 carbon atoms.

14. Process according to claim 2, wherein said alkyl or aryl groups are functionalized with one or more hydroxyl, carboxyl, or halide groups.

15. Process according to claim 3, wherein R.sub.1 and R.sub.2 are independently selected from the group consisting of methyl groups and butyl groups.

16. Process according to claim 9, wherein the total amount of anti-wrinkle agent composition is between 0.60% and 1.20% based on a weight of the hide/pelt as 100%.

17. Process according to claim 10, wherein the unhairing agent is urea or a thiol compound.

18. Process according to claim 11, wherein ii) comprises filtering hair from the solution.

19. Process according to claim 11, wherein iii) comprises use of phenolphthalein as pH indicator.

Description

EXAMPLE 1

[0033] Dutch cattle hide that has been soaked in the conventional way was used. Percentages are weight percentages compared to the weight of the pelt. The liming process comprised the following steps:

[0034] (i) Soaked hide was drummed in a mixture of water of 25 C., 0.03% of a sustainable surfactant mixture (ProSoak; obtainable from Stahl Europe BV), 0.15% of an unhairing enzyme (Bemanol RS-300; obtainable from Stahl Europe BV), 0.15% of sodium sulphide as unhairing agent, and anti-wrinkle agent composition for 20 minutes. The type of anti-wrinkle agent, the amount thereof and the amount of water used is indicated in Table 1 below.

[0035] (ii) To the drum was added 0.15% sustainable degreasing agent (ProDegreaze; obtainable from Stahl Europe BV) and 2.00% of lime for immunization. After 15 minutes of running, the drum was rested for 15 minutes.

[0036] (iii) Next, 0.85% of sodium hydrosulphide and 0.50% of sodium sulphide was added to start the unhairing. After 45 minutes unhairing was achieved for 95% and the hair was filtered from the bath during 30 minutes. After another 90 minutes of drumming, a mixture was added to the drum consisting of 30% of water, 0.02% of an emulsifier (Eusapon EM; obtainable from Stahl Europe BV) and 0.10% of a wetting agent (Eusapon W; obtainable from Stahl Europe BV). This was run for 30 minutes. Thereafter, the penetration of lime was monitored closely with phenolphthalein, as known to those skilled in the art. As soon as 80% of penetration was achieved the next step was carried out.

[0037] (iv) 80% of water was added, together with 1.00% of lime, 0.30% of sodium sulphide as unhairing agent and 0.02% of emulsifying agent (Eusapon EM; obtainable from Stahl Europe BV). The drum was programmed to run for 5 minutes and stop for 25 minutes subsequently, for 9 of those cycles, and drained afterwards.

[0038] (v) 100% of water was added to wash the unhaired and limed pelts and they were taken for fleshing and splitting.

[0039] Thereafter, using conventional methods, crust was obtained after Easywhite tanning (a tradename from Stahl Europe BV for chrome-free tanning), retanning, neutralization, dyeing and fatliquoring.

[0040] Chemical Oxygen Demand (COD) was measured according to ISO 15705. A lower COD value, expressed in mg per kg of skin/pelt, is better. BOD.sub.5 was measured according to EN 1899-1. A higher ratio of BOD.sub.5/COD means that the wastewater is more biodegradable and thus easier to treat. Therefore a high BOD.sub.5/COD can be considered to be more environmentally friendly.

[0041] The compositions of the various anti-wrinkling agent compositions in entries 2 to 7 of Table 1 are as follows: a mixture of 50 weight % of the indicated material, together with 20 weight % of urea and 30 weight % of water. Entries 2 and 7 are comparative examples, as ethanolamine is a primary amine that is commonly used as anti-wrinkle agent. The composition of the anti-wrinkling agent composition of entry 8 is as follows: a mixture of 70 weight % of the indicated material and 30 weight % of water.

[0042] The benzalkonium chloride, which is used in entry 5, is a mixture of N-alkyl-N,N-dimethyl-benzenemethanaminium chlorides, wherein the alkyl chains have various lengths of between 8 and 18 carbon atoms in each alkyl chain. It was purchased from Sigma-Aldrich.

TABLE-US-00001 TABLE 1 Anti-wrinkle % % antiwrinkle agent, water agent BOD.sub.5/ Leather Entry a mixture with soaking composition COD quality 1 None 40 None 0.28 Visible (ref) wrinkling 2 Ethanolamine 40 0.80 0.25 Good (comp) 3 Choline chloride 40 0.80 0.32 Good 4 Tetrabutyl- 40 0.80 0.45 Good ammonium bromide 5 Benzalkonium 40 0.80 0.32 Good chloride 6 Choline chloride 40 0.80 0.44 Good 7 Ethanolamine 100 0.60 0.30 Good (comp) 8 Only Choline 100 0.60 0.38 Good chloride*

[0043] The quality of the leather obtained was good after the treatment as described above using the anti-wrinkle agents of the entries 2 to 8, and only when no anti-wrinkle agent was used, in entry 1, the wrinkles were clearly visible in the leather. So, the anti-wrinkle agents based on the inventive quaternary ammonium salts are given the same good performance as the comparative primary amine anti-wrinkle agents of entries 2 and 7. The BOD.sub.5/COD ratio ranged between 0.32 and 0.45 when using anti-wrinkle agents based on the inventive quaternary ammonium salts, whereas the BOD.sub.5/COD was only 0.25 or 0.30 when using comparative primary amine of entries 2 and 7.