FR2650294A1 - PROCESS FOR TREATING SKINS AND SKINS OBTAINED - Google Patents

Abstract

Method for the antifungal and/or antibacterial treatment of hides. This method consists in treating these hides with a bath containing a lanthanum or cerium salt, for example a lanthanum acrylate.

Description

PROCESS FOR TREATING SKINS ,. AND SKINS OBTAINED

  ! The present invention relates to a method of treating skins and

the skins thus treated.

  It relates more particularly to a treatment making it possible to ensure a better conservation of a biological point of view thereof, in particular during the process of elaboration thereof.

or after tanning.

  Currently, skins are generally marketed in different forms: - in the raw state (salted, pickled, salted - dry and fresh, etc ...) - in the pickled state (treatment with a strong acid solution in the presence salt) - in the pretanned reversible state (BSH or BSS, wet white, dry white, for example) - in the tanned state (for example by a chromium treatment) - in the semi-worked state (called " stain ")

- or in the finished state.

  These skins are often transported. or stored in places not adapted for their conservation, in particular the conditions of humidity, healthiness are conducive to the development of a bacterial contamination

  and / or fungal skin. The different treatment solutions used

  in each stage of skin development may exhibit antibacterial or antifungal action. However, this one is not

  sufficient to provide sufficient protection.

  For this purpose, it has already been proposed to use products or

  compositions comprising compounds having antifungal or anti-bacterial activity, such as, for example, tri or pentachlorophenols, parametharesol, orthophenylphenol and their sodium salts, benzothiazole derivatives (for example, TCNTB), isothiazolones, metal salts such as

than zinc or copper salts.

  These specific products have disadvantages because they are generally difficult to eliminate. Thus, if the skins are treated with such products before or during river operations, they will be present in the waste recovered during the development of the skin, for example, fleshing. This polluted waste can not be

  recovered, especially in the manufacture of collagen.

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  Moreover, these specific products are found in the waters -

  skin treatment waste causing unacceptable pollution.

  table for the environment. These products may also have a toxic effect for wastewater treatment processes (biological treatment) implemented in water treatment plants.

  In addition, these products can also be troublesome in

  after tanning, for example.

  The object of the invention is, in particular, to remedy these drawbacks by proposing a method of treating the skins to protect them from fungal or bacterial attacks, which can be applied to all

  the stages or steps of the process of making a skin.

  For this purpose, the invention proposes a process for treating skins to protect them from fungal and / or bacterial attacks-of treating them with a treatment bath comprising at least one salt

lanthanum or cerium.

  By lanthanum or cerium salts is meant any salt soluble in water such as inorganic salts such as nitrates, chlorides, sulphates,

  for example, organic salts or organosulfonic or glucosulphonic

  nates. According to a preferred characteristic of the invention, the salts of

  lanthanum or cerium are organic salts derived from a carboxylic acid

  vinylic acid such as, for example, acrylic acid, methacrylic acid,

crylique.

  The preferred salts of the invention are acrylates and methacrylates.

lanthanum.

  The skins are treated with a quantity of lanthanum or cerium, expressed in oxide between 0.02% and 1.25%, preferably between

0.04% and 1.25%.

  These percentages represent the mass of compound, for example lanthanum (expressed in oxide) added to treat 100 kg of skin in tripe. By skin in tripe is meant a skin that has been shaved and freed from

fats and epidermis.

  The percentages given in the text below always express the amount of product added to treat 100 kg of tripe skin, except

otherwise stated.

  Advantageously when the salt is a vinyl carboxylic acid salt, free vinyl carboxylic acid is added to the

treatment solution.

  According to another characteristic of the invention, the quantity of vinyl anion or of vinylic acid, expressed as free vinylic acid, is

  advantageously between 0.5% and 5% of tripe skin, preferably

between 1% and 3%.

  This treatment bath can be used alone or in combination with a skin treatment bath, such as, for example, pickling, tanning or pretanning baths such as BSH or BSS baths, described for example in French Patent No. 2. 610 643 of the Leather Technical Center

Shoe and leather goods.

  This anti-fungal and antibacterial treatment bath is particularly suitable for treating tanned skins in order to preserve them against

  molds that damage the appearance of these.

  Thus the treatment bath according to the invention preserves the skins against the attack of fungi such as for example aspergillus niger, penicillium funiculosum, rhizopus nigricans, trichoderma

  viride or bacteria bacilus subtilis, escherichia coli.

  Another advantage of the process of the invention lies in the fact that the treatment agent does not irreversibly bind to the fiber

  of the skin and therefore can be easily removed by washing.

  Thus, subsequent processing of the latter will not be al-

  Teres. In addition, lanthanum or cerium are not harmful and therefore

  may be discharged into waste water.

  On the other hand, vinyl monomers (acrylic or methacrylate)

  residuals are readily polymerizable, this polymerisation

  inhibiting the annoying effect of these monomers.

  The process of the invention may be carried out by any known means and for example by impregnation with a treatment bath.

passage in a fuller.

  The subject of the invention is also skins treated according to

  method of the invention and comprising lanthanum and / or cerium.

  According to another characteristic, the treated skins comprise from 0.02% to 1.2% of lanthanum or cerium expressed relative to the weight of dry matter, that is to say after drying in a ventilated oven during

  6 hours at 105 ° C. and drying at this temperature at constant weight.

  The treated skins also include vinyl units either

  in monomeric form, either in polymerized form.

  Further details, advantages and objects of the present invention will become more apparent from the examples given below only.

for information.

  - A first series of tests was carried out on a cowhide

completely unhappy.

  This skin has been sliced to a weight of 2000 grams.

  Each slice was treated with an acid pickling solution, the composition of which will be given below: sample 1 control sample pickle bath: 100% water; 10% NaCl; 1.5% acid

sulfuric; pH = 2.8.

The treatment lasted 3 hours.

  These percentages express the mass of compound added per 100 kg

of skin in tripe.

  The same is true for the following examples.

- sample 2

  pickle bath: 100% water; 10% NaCl; 1.5% sulfuric acid

  America; 1.96% lanthanum nitrate (0.725% in La 2 O 3); pH = 4.0.

The treatment lasted 3 hours.

  Sample 3 A solution of lanthanum acrylate and acrylic acid containing 178 g / l of La 2 O 3 172.8 g / l and 476.3 g / l of acrylic acid is added to a pickling bath containing 100% water. and 10% of se} to obtain an acrylic acid concentration equal to 2% - and in La203 equal to

0.725%.

  The skin is treated for 3 hours at a pH = 5.8.

  These samples are stored in an enclosure at 18-20 C with a

relative humidity 85%.

  Under these storage conditions, mold stains appear

  1 sample after 18 days of storage while samples 2 and 3 show no evolution. A second series of tests was carried out on a skin of pickled cattle with a pickling bath comprising 100% water, 5% NaCl,

1.5% sulfuric acid.

  The skin was divided into strips which were then treated with

  stabilizing baths to obtain B.S.H.

  This stabilization treatment consists in adding to the pickling solution after neutralization 2% (weight of tripe) of aluminum polychlorosulphate (ie 0.16% expressed as Al 2 O 3) in the form of an aqueous solution having a basicity of 55%. a desulfation rate of 82% and an Al 2 O 3 content of 8.3% obtained according to the process described in

  European Patent Application No. 218487.

  During this treatment, an antifungal agent

  and / or antiseptic was added to the stabilization bath, with neutralization

  bathing to obtain a pH equal to about 4.

band no1

  Without antifungal and / or antiseptic treatment agent.

  band No. 2 A solution containing lanthanum acrylate and acrylic acid (172.8 g / expressed as La 2 O 3 and 476.3 g acrylic acid), so as to have 0.4% expressed as La 2 O 3 by compared to the weight of tripe

(skin weight).

  23.8 g of lanthanum acrylate are added to the stabilization bath to have a content of 0.04% expressed as La 2 O 3 based on the weight of the tripe. - band 4

  A conventional antiseptic agent marketed under the trade name

  "Busan 30" is added to the stabilization bath to

  concentration of 0.07% based on the weight of tripe.

  These different bands are stored in a wet room at a

  temperature of 18-200C with 85% humidity.

  Thus after 11 weeks of storage, only the control strip No. 1 is invaded by molds both in the full leather

  thickness as of the split flower.

  In addition, some of these bands have been subjected to

  chrome tanning or vegetable tanning.

  These tanning tests have shown that the treatment of skins with a bath according to the invention does not affect the tanning conditions and

  the properties of the tanned skins obtained.

  A lanthanum assay on BSH skins has shown that the lanthanum content relative to the dry matter is 0.07% for strip 3 and

0.46% for band 2.

Claims (9)

  1 / Antifungal and antibacterial treatment method for hides   characterized in that it consists in treating them with a treatment bath   comprising at least one salt of lanthanum or cerium. 2 / A method according to claim 1, characterized in that the salt of lanthanum or cerium is a soluble or dispersible salt in water selected from the group consisting of nitrates, halides, sulfates, organic salts.   3 / A method according to claim 2, characterized in that the organic salts of lanthanum or cerium are carboxylic acid salts   vinylic or organosulfonic, gluconates.   4 / A method according to claim 3, characterized in that the vinyl carboxylic acid salts are salts of acrylic acid, methacrylic acid. 5 / A method according to claim 4, characterized in that the bath of   treatment contains a free vinyl carboxylic acid.   6 / Method according to one of the preceding claims, characterized -en   this. that the mass of lanthanum or cerium expressed as added oxide for the treatment of skins is between 0.02% and 1.25% of skin in   tripe, preferably between 0.04% and 1.25%.   7 / A method according to one of the preceding claims, characterized in   the mass of vinyl carboxylate anion and / or vinyl carboxylic acid, expressed as the free vinyl carboxylic acid added for the treatment of hides, is between 0.5 and 5% of tripe skin,   preferably between 1% and 3% of tripe skin.   8 / Method according to one of the preceding claims characterized in   what the anti-fungal and antibacterial treatment bath is used   in combination with one of the skin treatment baths.   9 / A method according to one of the preceding claims characterized in   what it consists in treating tanned or pretanned skins.   Skins characterized in that they contain lanthanum or cerium. 11 / Skins according to claim 10 characterized in that they   contain vinyl groups in monomeric or poly-   mérisee. 12 / skins according to claim 10 or 11 characterized in that the lanthanum or cerium content expressed as oxide is between 0.04%   and 1.2% with respect to the dry matter.