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
  • C14C1/08—Deliming; Bating; Pickling; Degreasing
• • 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
  • C14C3/06—Mineral tanning using chromium compounds
• • 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
  • C14C9/00—Impregnating leather for preserving, waterproofing, making resistant to heat or similar purposes
  • C14C9/02—Impregnating leather for preserving, waterproofing, making resistant to heat or similar purposes using fatty or oily materials, e.g. fat liquoring

Definitions

• the present invention relates to a process for producing leather comprising a plurality of steps, characterized in that methanesulfonic acid is used in at least one step.
• Processes for making leather typically involve a variety of steps. Many leather making steps are carried out in the aqueous medium at a certain pH. The adjustment of the optimum pH is of great importance and influences the properties of the produced leather.
• the choice of a suitable acid to neutralize the leather has a significant influence on the quality of the leather produced. This is the case, for example, in the deliming step. For example, using too much acid can negatively affect the optical and physical properties of the leather, possibly because the raw hides swell too much. If one chooses a too weak acid, this can mean that the adjustment of the pH is slow or the acid or other substances needed for the production of the leather do not completely penetrate the rawhide.
• conventional leather production methods in the deliming step remove the lime residues adhering to the liming, for example with about 1% lactic acid, dilute acetic acid, formic acid or other organic acids.
• suitable acids are, for example, boric acid, phosphoric acid or carbonic acid.
• hydrochloric acid or sulfuric acid is also possible.
• the use of these acids in leather production has long been known to the person skilled in the art and is described, for example, in Römpp's Chemie Lexikon under the heading "Tannery”. For a subsequent Mineralgerbung the nakedness is adjusted sour by pimples, whereby as pimples usually inorganic acids and common salt, if necessary also with additions of organic acids serve.
• the object of the present invention was to provide a process for producing leather which does not have the disadvantages of the prior art which gives soft and attractive leather and is efficient to perform.
• the object has been achieved by a process for producing leather comprising a plurality of steps, characterized in that methanesulfonic acid is used in at least one step.
• Animal skins are the skins of any dead animals such as beef, veal, pork, goat, sheep, kangaroo, fish, ostrich or game. It is irrelevant to the present invention whether the animals whose hides one wishes to treat were slaughtered, were huntmännisch killed or have died from natural causes.
• Processes for making leather typically involve a variety of steps.
• the hair is removed from the animal skin.
• This step is also referred to as a shearing step.
• the animal skin is usually treated with basic substances such as lime. Frequently, sodium hydroxide, sodium carbonate, sulfides or organic sulfur compounds are also added.
• the deboning step for example, meat remnants and subcutaneous connective tissue are mechanically removed from the animal skin.
• the deliming step also: descaling, English: deliming
• the basic components from the depilatory step are partially or completely neutralized.
• the animal skin is loosened and prepared for the absorption of tannin and thus on the actual tanning.
• Suitable tanning methods include the use of mineral salts (chromium III, aluminum, zirconium or iron salts), vegetable tanning with vegetable tannins (tannins in leaves, barks, woods and fruits), tanning (synonymously tanning) with fish and marine oils ( Trane) or with fats of the brain, Synthetic tanning with synthetically produced tannins (Syntans, resin tannins, polymer tanning agents, polyphosphates, paraffinsulfochloride), aldehyde tanning (formerly formaldehyde, today mainly glutaraldehyde). It is also possible to combine different tanning procedures.
• mineral salts chromium III, aluminum, zirconium or iron salts
• vegetable tanning with vegetable tannins tannins in leaves, barks, woods and fruits
• tanning synthetic tanning with synthetically produced tannins (Syntans, resin tannins, polymer tanning agents, polyphosphates, paraffinsulfochloride), aldehyde tanning
• the leather After tanning, the leather is usually mechanically dehydrated (withering) and brought to a uniform thickness with folding machines.
• the final leather properties such as softness, color, fullness, structure, ductility, water absorption, etc. are determined by the wet finish. Further steps are often the retannage, deacidification or neutralization, dyeing, fatliquoring and fixation of dyes and fatty substances. Basically, you can retake all tanning agent groups described in the main tanning can be used.
• synthetic tanning agents, vegetable tanning agents and resin and polymer tanning agents are of particular importance in the retanning, since they often have a particularly favorable influence on the fullness and structure of the leather.
• the acid residues of strong acids are often neutralized, as a result of which, as a rule, a better resistance of the leather is obtained.
• the coloring is often done with dyes that form a chemical bond with the leather fiber.
• Advantageous dyes are distinguished not only by the good dyeing properties (for example, tacking properties on the leather, combinability, large color palette) and fastness properties, but also by low environmental impact.
• the natural leather color depends, among other things, on the tanning agent used.
• Chrome tannins often give a light, greyish-green intrinsic color, vegetable oils can, for example, yellow-brown - reddish brown.
• Aluminum salts and synthetic tannins often yield white to light beige leather.
• Glutaraldehyde and fatty tanning agents usually color the leathers yellowish.
• the fatliquors envelop the leather fibers with a thin film of grease. As a result, the fibers do not stick together so much during drying and can shift more easily against each other.
• leather can be dirt and water repellent, equipped to waterproof.
• steps are often carried out in the order given for preparation. However, within limits, it is also possible to execute them in other orders or to execute and combine steps together. Not all of the above steps need to be performed to produce leather. In addition, processes for producing leather may include other steps in addition to the aforementioned steps.
• methanesulfonic acid is used in at least one of the steps for the production of leather.
• Methanesulfonic acid serves primarily to adjust the pH.
• Methanesulfonic acid is preferably added to the animal skin at the beginning of the actual working step.
• the operation consists essentially of the neutralization of basic components with acids comprising methanesulfonic acid according to the invention.
• the use of methanesulfonic acid in a particular step is also understood to mean the addition of methanesulfonic acid before the actual working step or after the preceding working step, if this serves to prepare the actual working step.
• methanesulfonic acid is used in at least one of the following steps: deliming, pickling, pickling, brushing, tanning, retanning, dyeing, fatliquoring.
• Methanesulfonic acid is particularly preferably used at least in the case of deliming and / or pickling and / or pickling.
• methanesulfonic acid is used at least in the deliming step.
• Methanesulfonic acid is used according to the invention usually as an aqueous solution.
• methanesulfonic acid is used as 0.05 to 0.5% strength by weight aqueous solution, preferably 0.07 to 0.2% by weight and particularly preferably 0.08 to 0.15% by weight.
• methanesulfonic acid is used together with salts and / or other acids and / or acid derivatives. Suitable acid derivatives are, for example, esters or acid anhydrides.
• methanesulfonic acid is used with salts of methanesulfonic acid.
• Suitable salts of methanesulfonic acid include, for example, alkali metal or alkaline earth metal salts such as sodium, potassium, magnesium or calcium salts of methanesulfonic acid.
• methanesulfonic acid is used together with inorganic salts.
• Suitable inorganic salts are, for example, salts of sulfuric acid, hydrohalic acids, phosphoric acid, boric acid, carbonic acid, nitric acid.
• suitable inorganic salts are, for example, ammonium sulfate, sodium sulfate, sodium chloride, ammonium chloride.
• methanesulfonic acid is used together with salts of organic acids.
• Suitable salts of organic acids are, for example, ammonium, alkali metal or alkaline earth metal salts of organic acids, such as ammonium, sodium, potassium or magnesium salts of organic acids.
• Suitable salts of organic acids are, for example, salts of monocarboxylic acids or dicarboxylic acids.
• Suitable salts of organic acids are, for example, salts of formic acid, acetic acid, propionic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, tartaric acid, lactic acid, phthalic acid, terephthalic acid, maleic acid, fumaric acid.
• methanesulfonic acid is used together with other acids.
• Suitable other acids may be inorganic acids or organic acids.
• Suitable inorganic acids are, for example, sulfuric acid, hydrochloric acid, boric acid, carbonic acid, phosphoric acid.
• Suitable organic acids are, for example, monocarboxylic acids or dicarboxylic acids.
• Suitable organic acids are formic, acetic, lactic, formic, propionic, oxalic, malonic, succinic, glutaric, adipic, tartaric, lactic, phthalic, terephthalic, maleic and fumaric acids.
• methanesulfonic acid is used in combination with ammonium sulfate. In another embodiment, methanesulfonic acid is used in combination with formic acid.
• methanesulfonic acid is used in combination with one or more ammonium salts of dicarboxylic acids.
• methanesulfonic acid is used in combination with one or more aliphatic dicarboxylic acids.
• methanesulfonic acid is used in combination with one or more carboxylic acid esters.
• the amount of salts, other acids or acid derivatives can vary widely.
• an aqueous solution containing 0.05 to 0.2% by weight of methanesulfonic acid and 0.5 to 2% by weight of ammonium sulfate is used.
• a pH of 4 to 9, preferably 6 to 8.5 and particularly preferably 7.5 to 8.5 is set.
• the deliming step lasts from 30 minutes to 4 hours, in exceptional cases shorter or longer.
• the deliming step is completed in 45 to 90 minutes.
• Processes according to the invention are characterized in that they are simple to carry out and permit an efficient and rapid adjustment of the pH in the individual process steps. Furthermore, inventive methods allow the production of leather, which are characterized by advantageous optical and haptic properties. In particular, they are characterized by pleasant softness and do not swell so much, do not swell so much as leather, which are produced by conventional methods.
• the leathers produced according to the invention are characterized by a good softness and have a pleasant, appealing, fine and clean grain.
• the physical properties such as tensile strength, elongation at break or grain elongation of the leather produced by the process according to the invention are comparable or better than those of leather, which have been prepared according to the prior art.
• Another object of the present invention is leather, which has been produced by the process according to the invention.
• a rawhide of beef was depilated and fleshed. The depilation took place with the addition of quick lime and sodium sulfide.
• the leathers were treated with decalcifier according to Example 1 to 6 to adjust a pH of 8. The skins were first treated at room temperature for 20 minutes with a mixture A and then for 60 minutes with a mixture B. Subsequently, the skins were subjected to tanning and retanning with identical chromium-tanning formulations.
• methanesulfonic acid made it possible to adjust the pH in a shorter time and to give clean and flat raw skins which were not as swollen as skins were subjected to deliming without methanesulfonic acid.
• the leathers made using methanesulfonic acid in the deleting step are softer than leathers made according to the prior art and they have beautiful, fine and clean scars.
• the physical properties are comparable to or better than those of leathers made according to the prior art.

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

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• 2013
  • 2013-02-14 EP EP13155256.4A patent/EP2607499A3/fr not_active Withdrawn
• 2014
  • 2014-02-12 BR BR112015019537A patent/BR112015019537A2/pt not_active Application Discontinuation
  • 2014-02-12 CN CN201480008276.2A patent/CN104981549A/zh active Pending
  • 2014-02-12 KR KR1020157024903A patent/KR102230317B1/ko active IP Right Grant
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  • 2014-02-12 ES ES14703867.3T patent/ES2616043T3/es active Active
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  • 2014-02-12 WO PCT/EP2014/052691 patent/WO2014124951A1/fr active Application Filing
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• 2015
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