JPH03115500A - How to treat the skin - Google Patents

Abstract

PURPOSE: To apply antibacterial treatment to hide without exerting toxic action on biochemical waste water treatment applied to a water purifying plant by treating leather with a treatment bath containing La or Ce salt.

CONSTITUTION: A hide is treated with a treatment bath containing one or more kind of La or Ce salt (e.g. lanthanum nitrate-containing aq. sol.).

COPYRIGHT: (C)1991,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for treating hides and to hides so treated.

More particularly, the invention relates to a processing method which ensures a better preservation of the leather from a biological point of view, especially during the processing of the leather before or after tanning.

[Prior art and its problems] At present, hides are generally processed in various forms, that is, in their raw form (salted, brine-pickled, salted/dried, raw hide, etc.); In acid conditions (treatment with strong acid solutions in the presence of salts), in 0 reversible pretanned conditions (eg λ, B, S.

It is commercially available in the tanned state (for example by chroming), in the semi-finished state (referred to as "staining") and in the finished product state (Hl or B, S, S, wet white, dry white).

These skins are often transported or stored in locations that are not suitable for their preservation, especially the humid conditions that favor the occurrence of bacterial and/or fungal contamination of the skins. The various treatment solutions used in each leather processing step can exhibit antibacterial and antimicrobial activity. However, this is not sufficient to ensure satisfactory protection.

For this purpose, compounds with antimicrobial or antibacterial action are used, for example tri- or pentachlorophenol, p-metacresol, 0-phenylphenol and their sodium salts, benzothiazole derivatives (for example TCMTB).
It has been proposed to use substances or compositions containing, for example, isothiazolones, metal salts such as zinc or copper salts.

However, these particular substances present disadvantages. This is because they are generally difficult to remove. Thus, if the hides are treated with such substances before or during a series of operations, these will be present in the waste recovered during the processing of the leather, for example during freshing. These contaminated waste products cannot be recovered, especially in the case of collagen production.

Additionally, these specific substances are found in wastewater from leather processing and create unacceptable pollution to the environment. Additionally, these substances may have a toxic effect on wastewater treatment (biological treatment) provided to water treatment plants.

These substances may also be a nuisance in the processing of hides, for example after tanning.

[Problem to be Solved by the Invention] Therefore, the present invention proposes, in particular, a method for treating hides for protecting the hides from fungal or bacterial attack, which is applicable to all stages or processes of processing the hides. The purpose is to prevent the above-mentioned inconveniences.

[Means for Solving the Problem] To this end, the present invention provides a method for protecting hides from attack by fungi and/or bacteria, comprising treating the hides with a treatment bath containing at least one lanthanum or cerium salt. We propose a method for treating skin.

Here, lanthanum or cerium salts are, for example, nitrates,
Inorganic salts such as chlorides and sulfates; any water-soluble salts such as organic salts, organic sulfonates or gluconates are meant.

According to a preferred feature of the invention, the lanthanum or cerium salt is an organic salt derived from vinylic carboxylic acids, such as acrylic acid, methacrylic acid, etc.

Preferred salts of the invention are lanthanum acrylate and lanthanum methacrylate.

The skin contains 0.02% to 1, 25% expressed as oxides,
Preferably treated with lanthanum or cerium in an amount of 1.25%.

This % represents the weight (expressed as oxide) of the compound, e.g. lanthanum, added to treat 100 kg of depilated skin, where depilated skin means the skin that has been depilated and freed of fat and epidermis. do.

Note that the percentages shown below are for depilated raw hides unless otherwise specified.
, always represents the amount of substance added to treat OOkg.

Advantageously, when the salt is a salt of a vinylic carboxylic acid,
Free vinyl carboxylic acid is added to the processing solution.

According to another feature of the invention, the amount of vinyl carboxylic acid anion or vinyl carboxylic acid, expressed as free vinyl carboxylic acid, advantageously ranges from 0.5% to 0.5% of the depilated raw hide.
5%, preferably 1% to 3%.

This treatment bath can be used alone or as a leather treatment bath, such as a pickling bath, a tanning bath or, for example, B, S, H or B as described in French Patent No. 2610643 of the Center for Leather and Shoemaking Technology.
, S, S, bath.

This antibacterial and antibacterial treatment bath is particularly suitable for treating tanned hides to protect them from molds that impair their appearance.

Thus, the treatment bath according to the invention can remove skin from fungi, e.g.
Aspergillus niger
iger) Penicillium funiculosum (Pe
nicillium funiculosum), Rhizopus nigricans (Rhizopus nigri)
cans), Trichoderma bit (Tr:chode
rma vfride), and bacteria such as Bacillus subtilis,
Eschirichia col
i) protect against attacks by

Another advantage of the method of the invention is that the treatment agent is not irreversibly fixed in the leather fibers and can therefore be easily removed by washing.

Subsequent processing of the skin is thus not impaired.

Furthermore, lanthanum or cerium are not harmful and can therefore be dumped into wastewater.

Moreover, the residual vinyl monomers (acrylic acid or methacrylic acid) can be easily polymerized, and this polymerization suppresses the interfering effects of these monomers.

The method of the invention can be carried out by any known means, for example by impregnating the drum with a treatment bath.

A subject of the invention is also a hide treated by the method of the invention and containing lanthanum and/or cerium.

According to another characteristic, the treated hides also have an average weight of 10
After drying for 6 hours at 5°C and dehydrating to constant weight at this temperature, it contains 0.02% to 1.2% lanthanum or cerium.

The treated skin also contains vinyl units in monomeric or polymerized form.

Other details, advantages and objects of the invention will become apparent from the following examples, given by way of example only.

Examples A. A first series of experiments was conducted on fully decalcified cowhide.

This skin was cut into pieces weighing 2000 g. Each section was treated with an acid solution in a manic acid bath having the following composition.

Test "1 piece" 2 (control experiment) m: l O0% water, 10% NaCl2.1.5
% sulfuric acid, pH=2.8 Treatment lasted for 3 hours.

The above percentages represent the weight of the compound added to 100 kg of depilated raw skin.

This is the same in the example below.

Armpit and water: 100% water, 10% NaCl2.1.
5% sulfuric acid, 1.96% lanthanum nitrate (0,725%
La203), pi (=10) treatment continued for 3 hours.

172 in a pickling bath containing 100% water and 10% salt.
．． A solution of lanthanum acrylate and acrylic acid containing 8 g/fl of a203 and 476.3 g/β of acrylic acid was added to obtain an acrylic acid concentration of 2% and a La, zOs concentration of 0.725%.

The skins were treated in this bath for 3 hours at pH=5.8.

These specimens were tested at a temperature of 18-20'C and a relative humidity of 8
It was stored in a 5% chamber.

Under these storage conditions, mold spots appeared on control specimen 1 after 18 days of storage, whereas mold spots appeared on specimen 2.
and 3 showed no change.

B. A second series of experiments was carried out in 100% water, 5% NaCβ.
and cowhide treated with a manic acid bath containing 1.5% sulfuric acid.

The skin was divided into strips and these were then treated in a stabilizing bath to obtain B, S, H, skins.

This stabilization treatment involves adding 2% (based on the weight of the depilated skin) polychloroaluminum sulfate (
i.e. 0.16% expressed as 8β203) obtained by the method described in European patent application no.
It consists of adding as an aqueous solution having an Al2aOs content of .

During this treatment, antimicrobial and/or preservative agents were added to the stabilizing bath and the bath was neutralized to obtain a pH of about 4.

Nikasada Eyu No antibacterial and/or preservatives added.

A solution containing lanthanum acrylate and acrylic acid (expressed as Laies) in an amount of 0.4% expressed as LazO3 based on the weight (skin weight) of Tamagotan Eyu hair removal raw hide.
72.8 g and 476.3 g of acrylic acid).

''0.
23.8 g of lanthanum acrylate are added to the stabilizing bath to have a content of 0.04%.

A representative preservative commercially available under the trade name "Busan 30J" is added to the stabilizing bath to a concentration of 0.07% based on the weight of the hide.

These various strips were heated at a temperature of 18 to 20°C and a humidity of 85%.
Store in a humid room.

Thus, after 11 weeks of storage, only control zone No. 1 was attacked by mold on both the sufficiently thick leather and the cut surface.

Furthermore, some of these strips were subjected to chrome tanning or vegetable tanning treatment.

These tanning experiments demonstrated that the treatment of hides with a bath according to the invention does not affect the tanning conditions and the properties of the resulting tanned hides.

Quantification of the lanthanum of B, S, H, supports demonstrated that the lanthanum content on dry matter was 0.07% for band NO13 and 0.46% for band NO12.

In addition, we conducted an experiment on skin contamination with mold in a vetri dish.
The experiments were carried out by inoculating small leather specimens with microbial cells at a rate of 1X10'cells/cm'' of leather.

The thus inoculated test piece was placed in a kerose medium poured into a vetri dish. It is itself also inoculated with a suspension of the corresponding microbial cells.

These were incubated at 3Q°C in a constant temperature incubator.

The development of mold on the leather and gelose medium was observed.

In the first test, tanned with chromium salts and normally
Leather, referred to as "Wet Blue" leather, was treated with an antibacterial compound according to the invention or, as a comparative example, with a widely used known compound, namely a benzotriazole derivative marketed under the name "Busan". It was impregnated with a solution containing some antibacterial compound.

The lanthanum content or butane content, expressed as lanthanum oxide, was 0.4%.

The results obtained are summarized in the table below.

Follow the same instructions as above, except for B, S.

Another test was carried out using a leather pre-tanned with an aluminum solution, referred to as H1 leather.

Thus, a skin impregnated with 0.4% lanthanum (expressed as Lag Os) by lanthanum acrylate has 6
Leather impregnated with a solution of lanthanum acrylate in acrylic acid was 75% infected with mold after 10 days, and 75% after 24 days; It was observed that the uncontained skin was 100% infected after 3 days.

These tests were also carried out on hides that had undergone vegetable tanning treatment. Tests showed that a mixture of lanthanum acrylate and acrylic acid delayed mold attack for several days (approximately 6 days) under these test conditions, whereas untreated hides were attacked by mold very quickly (1 day). has been proven.

Claims (1)

[Scope of Claims] 1) A method for the antibacterial and antibacterial treatment of leather, which comprises treating the skin with a treatment bath containing at least one kind of lanthanum or cerium salt. 2) Lanthanum or cerium salt is nitrate, halide,
The method according to claim 1, characterized in that the salt is a water-soluble or water-dispersible salt selected from the group consisting of sulfates and organic salts. 3) The method according to claim 2, wherein the organic salt of lanthanum or cerium is a salt of vinyl carboxylic acid, organic sulfonic acid or gluconic acid. 4) The method according to claim 3, wherein the vinyl carboxylic acid salt is an acrylic acid or methacrylic acid salt. 5) The method according to claim 4, wherein the treatment bath contains free vinyl carboxylic acid. 6) The weight of lanthanum or cerium added for the treatment of leather, expressed as oxide, is 0.02
% to 1.25%, preferably 0.04% to 1.25%. 7) The weight of the vinyl carboxylic acid anion and/or vinyl carboxylic acid added for the treatment of leather, expressed as free vinyl carboxylic acid, is
．． 7. Process according to any of claims 1 to 6, characterized in that it is between 5% and 5%, preferably between 1% and 3%. 8) A method according to any one of claims 1 to 7, characterized in that an antibacterial and antibacterial treatment bath is used in combination with one of the skin treatment baths. 9) Process according to any one of claims 1 to 8, characterized in that it consists of treating tanned or pre-tanned hides. 10) A skin characterized by containing lanthanum or cerium. 11) A skin according to claim 10, characterized in that it contains vinyl groups in monomeric or polymeric form. 12) Claim 1 characterized in that the content of lanthanum or cerium is 0.04% to 1.2% on dry matter expressed as an oxide.
The skin according to 0 or 11.