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
  • C14C1/00—Chemical treatment prior to 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
• • 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
  • C14C1/00—Chemical treatment prior to tanning
  • C14C1/08—Deliming; Bating; Pickling; Degreasing

Definitions

• the present invention relates to biologically stabilized and untanned hides and the process for obtaining these hides.
• these skins can be delivered in the raw state, having undergone a simple treatment intended to prevent or stop microbial development (salting, salting and drying, drying ). They can be delivered in pickled state, that is to say after having undergone a simple preparation by treatment with a strong acid solution in the presence of salt, or even after having been tanned with chromium (wet-blue treatment ) or otherwise; finally, the skins can be delivered in the semi-worked state (stain) or in the finished state.
• One of the important problems facing the leather industry at the moment is to be able to detect the defects existing in the skins as early as possible in the leather transformation dough, so as to allow a better orientation of the skins, according to their quality and market needs. This information is also essential for specialists in the various stages of preparation to enable them to possibly modify their treatment method.
• any orientation from the raw state to the finished state is accompanied by an improvement in the possibilities of assessing the quality of the material, an increase in its stability and its lifespan, optimization of the material balance in manufacturing; in return, the field of diversification becomes more and more narrow.
• BSH Wet White Stabilized
• These light-colored wet skins contain about 60% water, from 1 to 10% mineral matter, less than 1% aluminum oxide, the rate of dermal substance being 85-90%.
• BSH skins have certain drawbacks, especially due to their high water content, which makes them difficult to handle and greatly increases their transport costs.
• the Applicant has therefore established selection criteria for the numerous wetting chemical agents in order to determine those which were capable of satisfying these requirements. These criteria are as follows:
• These agents must have good stability in a pH zone ranging from 2.5 to 4.5.
• tanning must be compatible with the products subsequently used for tanning, whether vegetable tanning, mixed tanning (vegetable-synthetic) or mineral tanning (chromium, zirconium, titanium).
• the present invention relates to clear skins, biologically stabilized and not tanned and which will be referred to in the following as "Dry Stabilized White", which are characterized in that, completely free of chromium, they have a moisture content between 15 and 20%, a maximum mineral content of 1 to 12%, an aluminum oxide content of 0.7 ⁇ 0.2%, a possible content of acrylic derivatives of 2%, in that their pH is around 4.0, and their dermal content is around 85 ⁇ 3%. and in that they are able to rewet in less than an hour.
• Dry Stabilized White which are characterized in that, completely free of chromium, they have a moisture content between 15 and 20%, a maximum mineral content of 1 to 12%, an aluminum oxide content of 0.7 ⁇ 0.2%, a possible content of acrylic derivatives of 2%, in that their pH is around 4.0, and their dermal content is around 85 ⁇ 3%. and in that they are able to rewet in less than an hour.
• the invention makes it possible to have, after the pickling stage where the skin is still diversifiable but relatively fragile, skin which can be described as biologically preserved, which has the following advantages: -easy storage and transport, in particular because of its low moisture content; inertia vis-à-vis aging, -reasonable production cost, -very broad aptitude for diversification (including flower and crust towards different destinations); -better integration into the environment (reduced water pollution and obtaining non-chrome-plated solid waste); - ability to subsequently undergo all subsequent tanning treatments.
• the invention also relates to a process for obtaining so-called dry white stabilized skins described above.
• This process is of the type consisting in subjecting the cold de-scaled and crystallized skins to a pickling treatment optionally in the presence of acrylic resin and then, after resting, to a pretanning treatment using aluminum salts and it is characterized in what one introduces, in any phase of the treatment, a chemical agent facilitating rewetting and allowing the skin to preserve, after drying, a residual humidity close to 20%, and in that the skin is thus subjected treated on drying.
• the chemical agent facilitating rewetting is introduced into the pickling step.
• said chemical agent is introduced into the pretanning stage.
• said chemical agent is deposited on wet skin by any spraying, spraying or coating process, on the flesh side and / or on the flower side.
• said chemical agent is introduced in a subsequent step, after pickling and pretanning.
• the chemical agent facilitating rewetting is chosen, as specified above, from the group consisting of polyalcohols, condensates of fatty alcohols on ethylene oxide and condensates of alkyl phenols on ethylene oxide.
• the inventors also determined that it was especially important, in order to allow the subsequent rewetting and degreasing of the skins thus treated, to incorporate a mixture of hygroscopic compound and emulsifier as well as a co-surfactant capable of promoting the setting in micro-emulsion of the natural fats present in the native skin, this in order to improve the qualities, the presentation and the market value.
• a certain amount of emulsifier having a determined hydrophilic lipophilic balance (HLB) determined identical to the required HLB (RHLB) of natural fats is incorporated into the skins. of a cosurfactant in order to allow their dispersion in the form of microemulsions during rinses carried out at a temperature above the melting point of these fats in the presence of salts avoiding acidic swelling if necessary.
• HLB hydrophilic lipophilic balance
• the skin is thus communicated with good hygroscopic power, improved rewetting facilities associated with lubricating properties. , antifungal and antibacterial properties and an absence of crystallization.
• the preferred relative proportions of the compounds to be used are as follows: -Emulsifier 30 to 70% -Hygroscopic product 20 to 60% -Cosensitive 5 to 15% -Fungicide or bactericide 1 to 10% -Lubricant 5 to 15%
• the cosurfactants can be defined as hydrophilic products (alcohols, glycols or polyglycols, amines, amino alcohols for example) which, added to the surfactants, ensure the production of microemulsions by increasing their H.L.B.
• the emulsifiers are chosen from oxyethylenated compounds resulting from the condensation of ethylene oxide or propylene oxide on organic chains, such as octyl or nonylphenol, polyols, alcohols, with a chain between C8 and C18, having an H.L.B. between 6 and 18 or a mixture of two or more compounds of this type.
• the hygroscopic product is chosen from the following compounds: glycerol, polyglycerol, sorbitol, trimethylolpropane, polyethylene glycol alone or as a mixture, alkaline or alkaline earth salts hygroscopic and deliquescent and in particular chlorides of this type.
• the fungicides and bactericides are preferably quaternary ammonium salts such as trimethyl cetyl ammonium chloride or any other salt of this type combining antiseptic properties with wetting properties.
• the lubricant is advantageously chosen from aliphatic hydrocarbons with a chain between C15 and C30.
• the mixtures of these compounds are used at a rate of 0.5 to 6% of the weight of the tripe skins, depending on their nature, the state of dryer to which it is desired to wear the skins in the dry stabilized white or dry-white form, in order to allow rewetting and / or degreasing under the best conditions.
• compositions can also be added after rewetting on the skins, after draining the bath to allow their degreasing, if the quantities used during the preparation of the B.S.S. were insufficient.
• the pH of the bath is close to 3.2-3.3.
• the “White Stabilized Wet” skin is wrung out, which contains approximately 60% water, 7 to 10% mineral matter and less than 1% aluminum oxide, the level of dermal substance rising to 85-90% of dry weight.
• the skins thus obtained can be easily sorted and can be stored at least six months before being subjected to subsequent tanning and finishing treatments.
• a drying test of the skin obtained in Example 1 leads to a rigid and brittle skin which is very difficult to store by stacking and which, moreover, is not easily rewettable.
• Example 2 Preparation of BSS, without prior degreasing of the skin; this process is more particularly intended for raw materials containing few natural fats and easily rewettable (veal or bovine crusts, skin of maximum thickness 0.8 mm).
• a quantity of soluble mineral agents is added making it possible to obtain an ionic strength adapted to the optimal conditions of acidification or pickling of the skins:
• Sodium chloride or sulfate Potassium chloride or sulfate Calcium chloride Mixture of acid salts, aromatic or aliphatic acids. Agitation of the skins in this bath for 10 to 30 minutes.
• the quantities of stabilization products used as well as the physicochemical conditions of the reaction must lead to the production of a stabilized material whose shrinkage temperature is at least 55 ° C and the pH between 3.5 and 4.5.
• This spin is not essential, however: in some cases, stacking or draining the skins is sufficient.
• a white preparation stabilized in the wet state is incorporated into a preparation allowing both drying without effects side effects such as migration of adjuvants or parasitic recrystallizations, excellent rewetting for the skin, re-manufactured at a later stage and preparation for the degreasing operation essential for the successful production of quality leather from BSS
• the preparation contains a mixture: - emulsifying and wetting agents of the nonionic type (oxyethylation products of amines, amides, alkylphenols and alkylnaphthols, fatty acids or alcohols); - hygroscopic agents such as glycerol, glycol and / or sorbitol or alcohols.
• nonionic type oxyethylation products of amines, amides, alkylphenols and alkylnaphthols, fatty acids or alcohols
• - hygroscopic agents such as glycerol, glycol and / or sorbitol or alcohols.
• the skins brought to the wet stabilized white state are grazed for 15 minutes with an amount of 4% calculated relative to the weight of the goods to be treated with the above preparation. They are then stored 24 hours and then dried.
• Example 3 Preparation of BSS, without degreasing the skin; this process is more particularly intended for raw materials with an average content of natural fats (3 to 6%), (goats, calves, bull calves).
• a compound of the food oil or food auxiliary type with a cationic nature (hydroxyethylated derivative of fatty amines) is added in amounts of between 0.2 % and 1.5%.
• the operation is carried out initially in a similar fashion to that of Example 2, up to the stages of storage and spinning.
• a white stabilized material is incorporated in the wet state. preparation allowing at the same time a separation without side effects of the migration type of adjuvants or parasitic recrystallizations, an excellent rewetting for the skin put back in later manufacturing and a preparation for the degreasing operation essential to the success of the leather manufacturing quality from BSS
• the preparation contains a mixture: - emulsifying or wetting agents of the nonionic type (oxyethylation products of amines, amides, alkylphenols and alkylnaphthols, fatty acids or alcohols); - hygroscopic agents such as glycerol, glycol or sorbitol or alcohols.
• nonionic type oxyethylation products of amines, amides, alkylphenols and alkylnaphthols, fatty acids or alcohols
• - hygroscopic agents such as glycerol, glycol or sorbitol or alcohols.
• this mixture is as follows: Octylphenol with 12 Moles of ethylene oxide: 60 parts Glycerol: 30 parts Butylglycol: 10 parts
• the skins brought to the wet stabilized white state are grazed with an amount of 4% of this mixture, calculated relative to the weight of the goods to be treated with the preparation described above, for 15 minutes. They are then stored for 24 hours and then dried as in Example 2.
• Example 5 Preparation of BSS, with prior degreasing of the skin, more particularly intended for raw materials with a high content of natural fats.
• the skins are first fulled in a temperate bath containing an emulsifier and a solvent for natural fats or a commercial preparation, the composition of which is obtained from these basic agents.
• degreasing takes place in two or even three successive stages interspersed with rinses.
• the degreased wet skins are then drained and then chained according to a procedure of the type of that of Example No. 2.
• Example 6 Preparation of BSS, with prior degreasing of the skin, more particularly intended for raw materials with a high content of natural fats.
• the skins are first fulled in a temperate bath containing an emulsifier and a solvent for natural fats or a commercial preparation, the composition of which is obtained from these basic agents.
• degreasing is carried out in two or even three successive stages interspersed with rinses.
• the mixture is as follows: Alkylphenol with 10 Moles of ethylene oxide 95 parts Butanol 5 parts
• Example 4 After degreasing, the bath is emptied and the preparation used in Example 4 is applied to the skins, using only 2 to 3% of the composition described. The skins are then stored and dried according to the procedure described in Example 2.
• B.S.S. obtained by implementing the methods described in examples 2 to 6 retain a humidity level of approximately 18 to 20% which allows them to be easily integrated into the cycle of subsequent manufacturing. They easily rewet in less than an hour. There is therefore, after the pickling stage, a biologically preserved skin, with all the advantages described above.
• the process according to the invention applies to the preparation of BSH and BSS of all skin types, whether or not dehaired, such as cattle, sheep, goats, pigs, reptiles, birds, fish, amphibians, waterfowl.

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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)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
• Diaphragms For Electromechanical Transducers (AREA)
• Immobilizing And Processing Of Enzymes And Microorganisms (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Detergent Compositions (AREA)
• Medicines Containing Material From Animals Or Micro-Organisms (AREA)
• Parts Printed On Printed Circuit Boards (AREA)
• Inorganic Insulating Materials (AREA)
• Chemical And Physical Treatments For Wood And The Like (AREA)
• Medicines Containing Antibodies Or Antigens For Use As Internal Diagnostic Agents (AREA)
• Radiation-Therapy Devices (AREA)
• Preventing Corrosion Or Incrustation Of Metals (AREA)
• Cosmetics (AREA)
• Medicines Containing Plant Substances (AREA)
• Hydroponics (AREA)
• Fertilizers (AREA)

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ID=9348017

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Cited By (3)

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Citations (2)

• 1987
  • 1987-02-11 FR FR8702035A patent/FR2610643B1/fr not_active Expired
• 1988
  • 1988-01-29 IN IN76/DEL/88A patent/IN172177B/en unknown
  • 1988-02-01 ZA ZA880692A patent/ZA88692B/xx unknown
  • 1988-02-02 CA CA000557913A patent/CA1299822C/fr not_active Expired - Lifetime
  • 1988-02-09 NZ NZ223463A patent/NZ223463A/xx unknown
  • 1988-02-09 MX MX010344A patent/MX170629B/es unknown
  • 1988-02-10 JP JP63027802A patent/JPS63202700A/ja active Pending
  • 1988-02-10 EP EP88420039A patent/EP0281486B1/de not_active Expired - Lifetime
  • 1988-02-10 DE DE8888420039T patent/DE3861976D1/de not_active Expired - Fee Related
  • 1988-02-10 BR BR8800542A patent/BR8800542A/pt not_active Application Discontinuation
  • 1988-02-10 AT AT88420039T patent/ATE61634T1/de not_active IP Right Cessation
  • 1988-02-10 AU AU11484/88A patent/AU613338B2/en not_active Ceased
  • 1988-02-10 ES ES88420039T patent/ES2021157B3/es not_active Expired - Lifetime
  • 1988-02-11 PT PT86747A patent/PT86747B/pt not_active IP Right Cessation
  • 1988-02-11 KR KR1019880001289A patent/KR960011115B1/ko not_active IP Right Cessation
• 1991
  • 1991-05-22 GR GR91400657T patent/GR3001981T3/el unknown

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