Classifications

• • C—CHEMISTRY; METALLURGY
  • C14—SKINS; HIDES; PELTS; LEATHER
  • C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
  • C14C3/00—Tanning; Compositions for tanning
• • C—CHEMISTRY; METALLURGY
  • C14—SKINS; HIDES; PELTS; LEATHER
  • C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
  • C14C3/00—Tanning; Compositions for tanning
  • C14C3/02—Chemical tanning
  • C14C3/04—Mineral tanning

Definitions

• the present invention relates to the tanning of leathers and it relates, more particularly, to the technical field of leathers intended to form all or part of clothing elements and, more especially, still leathers intended for the manufacture, at least in part, of shoes.
• French Patent No. 2,364,969 describes a process for protecting leathers against fungi consisting in tanning the hides in a tanning liquid containing usual tanning ingredients and the presence of 0.4 to 1.8 g of p -toluyl diiodomethylsulfone for 10 kg of skins.
• usual ingredients are cited those containing chromium sulfate and sulfuric acid.
• iatrogenic diseases corresponding to accidents caused by the absorption of the skin by antimycotic and fungicidal products.
• iatrogenic diseases are known to produce various manifestations, ranging from mild burns to severe allergies and complex forms.
• the object of the invention is to solve the above problems by proposing a new tanning process making it possible to make hides and skins mycostatic and antimycotic, in a durable way in time, without risk of allergic accident, even when the products made with such hides and skins are worn frequently and intensively.
• Another object of the invention is to propose a new tanning process including, to achieve the object of the invention, a treatment phase which can be applied, without any loss of efficiency, at any stage of the tanning proper , that is to say from the confit to the last finishing operations.
• An additional object of the invention is to propose a new tanning process which can be implemented for all types of hides and skins, without causing any modification of the essential qualities sought, that is to say fineness, flexibility, mechanical resistance, etc.
• the method according to the invention gives leathers mycostatic properties by fixing a biocidal agent to the leather fiber by means of an insoluble metal complex and having basic functions giving it tanning properties.
• the method according to the invention makes it possible to tan hides and skins from insoluble basic metal complexes formed in situ and on which it is possible to fix antiseptic, bactericidal, fungicidal, germicidal, antimycotic and more generally biocidal agents in order to their confer a mycostatic, bacteriostatic, fungistatic or more generally biostatic power.
• These basic insoluble metal complexes having a tanning activity can be formed in situ on the fiber by the reaction of two water-soluble salts or by the fixing of a salt insoluble in water but soluble in an emulsifiable solvent and of course having the basic character already mentioned.
• biocidal agent which can be used in a water-soluble form or used in a solvent. In both cases, it will react with the free basic functions of the insoluble and tanning metal complex to fix it in an insoluble form.
• This process can be used alone or in combination with other conventional tanning agents such as metal salts of chromium, iron, aluminum, silica, zirconium, etc. with tanning properties, or even proven vegetable or synthetic tannins. It can be used for pretanning, tanning or retanning.
• conventional tanning agents such as metal salts of chromium, iron, aluminum, silica, zirconium, etc. with tanning properties, or even proven vegetable or synthetic tannins. It can be used for pretanning, tanning or retanning.
• the set of anions may be replaced by (A) or by (A-) and an anion not specified by (a) or (a-) or in a more general and precise manner (a n- ) .
• the set will be (C) and an unspecified cation (c) or according to the protocol adopted for the anions (cm +).
• Basicity will be indicated in a global formula by a basic (OH) group capable of forming by dissociation of the product an ionic or ionized particle (OH) -.
• (M) will represent all of the antibacterial or bactericidal, antifungal or fungicidal or even antiseptic antimycotic agents and, more generally, biocides. A biocide from this list and not specified will be indicated by (m) in a general or global application.
• Monovalent acids derived from fluorine, chlorine, iodine and bromine are not to be considered interesting except with tri or tetravalent metals. The same is true for nitrogen anions which are monovalent with the same reservations.
• chromium, iron, zirconium and aluminum used in the form of basic insoluble complexes.
• Naphthenic acid and its salts dimethylthiocarbamic acid and its salts, 2 mercaptobenzothiozol and its salts, diethyldithiocarbamic and its salts, dimethyldithiocarbamates, ethylene dithiocarbamate, ethylxanthate, isopropylxanthate and phenylacetate undethenylacetate, and ethylphenylacetate nitrophenoxyacetatic acid and nitrophenoxyacetates, cresylic acid (cresol) and cresylates, bensuldazic acid and bensuldazates, 2 phenylphenol and salts, pentachlorophenol and salts, tetrachlorophenol, triphenylantimoine, triphenylboluth, parphenol, parethylphenol, parphenophenol, parethylphenol, parethylphenol, parphenophthalophenol, parethylphenol, parphenophenol
• the number and the substances are not limited. All that matters is the mode of binding of the biocide to the leather fiber by means of a basic insoluble and tanning complex.
• precipitated complexes have been defined as basic. This character is very useful in tanning to allow efficient tanning. It is this basicity which gives such character to cations such as chromium, iron, alumina, zirconium and silicon, etc.
• the tanning is obtained by metal hydroxides. Trivalent and sometimes tetravalent cations are used to the exclusion of all others.
• so-called “masking agents” are used which do not insolubilize the basic forms but on the contrary dissolve them.
• the tanning factor remains the basicity and the versatility equal to or greater than 3 which makes it possible to crosslink or three-dimensional the bonds between the collagen fibers by cationic bridges and this in a statistical manner.
• Tanning with cationic hydroxides can be expressed with the conventions adopted (c, OH) and by tanning becomes (leather) U (c) and (c) is tri or tetravalent.
• 5 salts can be formed: 2 acids, a neutral and 2 basic. It appears that the number of basic salts is always equal to n - 1 and that of the acid salts to m - 1.
• the anions can be introduced into the final composition either in the form of soluble salts directly giving an insoluble basic complex, or be obtained by reaction of certain compounds to obtain the one that is sought, or still go through the stage of a third solvent which will be reacted in solution or in emulsion.
• barium salts (Ba) to transform Na 2 SO 4 into BaS0 4 which is insoluble.
• the complex (c, m) gives all the desired reactivity to the antiseptic (m) to impart mycostaticity to the leather fibers tanned by the pair (c, a).
• the jersey is kept in contact with the leather for 12 hours in an atmosphere of 100% humidity and at a temperature of 37 ° C.
• the jersey is then separated from the leather and left for 12 hours at 20 ° C and a humidity of 60%.
• the leather pieces After microbial impregnation and drying, the leather pieces will be placed in a culture broth most favorable to the strain tested, at the pH and temperature most favorable for the development of each species. With a really mycostatic leather, there must be no bacterial development (negative test).
• a leather sample is then placed in a PETRI box with the most suitable culture broth for the strain studied and seeded with the bacteria, yeasts and fungi chosen, even on the leather sample.
• the cultures must develop on all the surface of the box except in contact with the leather above and below.
• the extract thus obtained is studied with very sensitive detection methods (infrared spectrophotometer for example).
• very sensitive detection methods infrared spectrophotometer for example.
• the advantage of infrared spectrophotometry is to be able check whether the biocidal compound has migrated.
• anions it is preferable to choose, from list (A), direct and indirect sulfides, phosphates and borates, as well as silicates.
• dimethylthiocarbamate, undecylenic acid and phenylphenol 2 will preferably be chosen.
• the results at minimum doses give excellent results.
• the tanning process can be applied once or several times at the various stages of manufacturing: pre-tanning,
• this pH will be obtained by adding baking soda dissolved in hot water (60 ° C).
• the amount of bicarbonate depends on the composition of the initial pickle.
• sulphhydrate a phosphate, a polyphosphate, or even a silicate. It is retanned with chromium, vegetable tannin or synthetic.
• chromium oxide binds to the leather fiber and releases sulfuric acid which dissolves the zinc oxide to form zinc sulfate. This is induced in the notion of tanning.
• the leather is intended to make dark colors, it is advisable to replace all or part of the zinc sulphate with copper sulphate.
• the dyeing and feeding operations can be done without intermediate drying.
• part of the zinc sulphate can be added or replaced by copper sulphate. To give weight and a little firmness, you can also add 7 to 14% of barium chloride.
• the SANDOLIX WWL can be replaced by any emulsifier containing a percentage of sulfated or sulfonated oil, or even sulfited.
• sheepskins for linings it is unnecessary to add food, but it is desirable to add 0.6% of undecylenate of soda at the same time as 2-phenylphenol. This operation is done hot but can be done cold without bath.
• Example 5 Special method for leather with soles:
• Sodium diethyldithiocarbamate can be replaced with sodium bensuldazate.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Treatment And Processing Of Natural Fur Or Leather (AREA)

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• 1982
  • 1982-05-12 FR FR8208615A patent/FR2526809A1/fr active Granted
• 1983
  • 1983-05-10 EP EP83420083A patent/EP0094329B1/fr not_active Expired
  • 1983-05-10 DE DE8383420083T patent/DE3361908D1/de not_active Expired
  • 1983-05-11 US US06/493,727 patent/US4484925A/en not_active Expired - Fee Related

Non-Patent Citations (1)

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