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
  • C14C11/00—Surface finishing of leather
  • C14C11/003—Surface finishing of leather using macromolecular 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
  • C14C13/00—Manufacture of special kinds or leather, e.g. vellum

Definitions

• the present invention relates to a method for the treatment of a semimanufactured product made of leather or fabrics similar to leather, and an item made from a semimanufactured product treated according to such a method.
• the present invention is targeted in particular at the processing of leather or imitation leather to be used to produce items destined to come at least partly into contact with the skin of an end user.
• Possible examples of these items are articles of clothing (jackets, coats), footwear, watchstraps, small leather items (bags and parts thereof, wallets), coverings for objects of various nature, such as coverings for eyewear, seat coverings (i.e. for automobiles).
• this list is provided by way of non-limiting example.
• One of the requirements related to the use of hide, leather and imitation leather in similar products is that of ensuring a high degree of comfort for the user. Not only must the leathers be soft and comfortable, but they must also ensure a high degree of water vapour permeability, so that when the leather is in contact with human skin, the perspiration produced by the user does not cause an unpleasant feeling when the item is worn.
• a further requirement is that of limiting the production of unpleasant odours caused by perspiration produced by the user. This requirement is particularly important in the footwear sector, where unpleasant odours frequently occur due to perspiring produced by the user's feet when wearing the footwear.
• silver has antiseptic, deodorant and antibacterial properties and that it is used for this purpose for example also in body deodorants.
• Document JP 2006 089583 A discloses leather, coated with silver, which is antiseptic and water vapor- and air-permeable and its use for shoes.
• Document RU 2 160 784 C1 discloses the finishing of leather with an aqueous solution of casein and an aqueous paint composition containing casein, pigment, water and wax emulsion and clothes obtained from said finished leather.
• Document KR 2006 0000291 A discloses an antibacterial fabric which contains a polyurethane layer that comprises silver particles.
• the problem underlying the present invention is therefore to provide a method for the treatment of leather (or of fabrics similar to leather) that is able to at least partly overcome the drawbacks mentioned with reference to prior art.
• the problem underlying the present invention is to provide a method for the treatment of leather or of fabrics similar to leather capable of offering a high degree of comfort, and a high level of breathability and of reducing odours caused by perspiration produced by the user's skin.
• a further objective of the present invention is to provide a method for the treatment of leather or fabrics similar to leather with limited environmental impact.
• the method according to the present invention is aimed at the treatment of leathers, in particular leathers of various kinds, but can also be used to treat fabrics similar to leather, such as imitation leather.
• leathers in particular leathers of various kinds
• fabrics similar to leather such as imitation leather.
• the method according to the invention firstly comprises a step to provide a semimanufactured product to be treated.
• This semimanufactured product can for example comprise a leather pre-tanned with known procedures.
• Treatment of the semimanufactured product takes place through the application thereto, according to procedures to be described, of a special treatment solution which is prepared according to specific procedures.
• the treatment solution is not necessarily applied to the entire semimanufactured product, but preferably only to one surface thereof.
• only one side of the leather is treated with the method according to the invention.
• the treatment is limited to the portion of the leather destined to come into contact with the user's skin.
• the treated surface is that destined to delimit the seat for the user's foot and which therefore will come into contact therewith.
• the treated surface is the inner surface of the watchstrap, i.e. the surface that will come into contact with the skin of the user's wrist.
• the treatment solution to be applied to the semimanufactured product includes a binder solution based on natural proteins in aqueous solution and silver in granules.
• the natural proteins used in the binder solution can be of various type. Preferably, they are selected from the group consisting of casein, egg albumin, blood albumin.
• the preferred binder used in the solution is in any case casein as this has the capacity to absorb moisture (which can, for example, derive from perspiration of the foot when the semimanufactured product is used to manufacture footwear).
• Casein is a phosphoprotein which can be obtained from milk through appropriate treatment processes (e.g.: pressure, fermentation, acidification).
• the binder solution it is possible for the binder solution to be provided with a combination of casein with albumin. In fact, this combination allows a sufficiently shiny film to be obtained on the leather.
• the binder solution can also comprise further additives suitable to give the leather specific characteristics.
• additives can include one or more of the following additives: linseed mucilage, cellulose derivatives, such as carboxymethyl cellulose, gelatin, lac, soaps.
• Linseed mucilages and cellulose derivatives give the films a high filling capacity on the leather.
• Gelatin gives the leather a soft handle and pasty texture.
• Lac gives the leather shine and homogeneity.
• the binder solution contains plasticizers suitable to reduce the stiffness, fragility and elasticity of the film of protein solution once this has been applied to the leather.
• the plasticizers are preferably selected from the group consisting of: sodium sulphoricinate, higher alcohols, glycols, glycerines, natural oils, natural waxes.
• natural oil it is possible, for example, to use medium sulfonation castor oil.
• Natural waxes can be of animal or vegetable origin.
• the vegetable waxes can be selected from a group consisting of: carnauba, which is extracted from the leaves of the Brazilian carnauba plant; montan, extracted from peat and lignite; candelilla, which is extracted mainly from the trunk of a Mexican plant.
• Animal waxes can instead be selected from the group consisting of: secretions from insects, such as beeswax; secretions from sebaceous glands, such as lanolin; secretions extracted from the adipose tissues of mammals, such as the sperm whale or whale.
• the absence of chemical solvents limits the overall environmental impact of the treatment.
• the items produced from semimanufactured products treated with the method according to the invention ensure high ecological quality standards.
• a further advantage linked to a binder solution of this type is that the presence of natural proteins ensures that the possibility of causing allergies in the end user is low.
• a further advantage linked to the use of an aqueous binder solution is the possibility of producing very thin, transparent and shiny finishes, which allow the leather to retain its natural water vapour permeability , while offering a high degree of comfort. Moreover, the antiseptic properties of silver are increased by the fact that it is immersed in a vapour permeable substance.
• the binder solution has anionic charge and, preferably, a pH of 8.
• the percentage of casein in the binder solution is preferably between 6% and 12%, even more preferably equal to 8%.
• the binder solution used is the solution called Hydrofin TU TM, manufactured by S.I.C. International TM .
• the granules of silver of the treatment solution preferably comprise granules of pure or substantially pure silver.
• the granules of silver in the treatment solution have a grain size of less than or equal to 10 microns.
• a part of the granules has a grain size of less than 10 microns.
• a part, preferably 50%, of the granules of silver has a grain size of less than 7 microns.
• Preparation of the treatment solution from the binder solution and from the granules of silver with the aforesaid properties comprises a series of successive steps.
• the binder solution and the granules of silver are mixed, preferably in a ratio of 1:10 (i.e. with one part of powdered silver and ten parts of binder), dispersing the silver in the binder solution.
• the suspension thus obtained is then mixed until obtaining a substantially homogenous paste.
• water is subsequently added to the paste thus obtained, in such a way as to obtain a diluted solution.
• water is added in a quantity such that in the treatment solution the granules of silver reach a concentration of between 7 and 12 g/l, preferably equal to 10 g/l.
• the solution thus obtained is then kept under stirring, for example using a blade stirrer.
• the maintenance speed is preferably between 250 and 350 rpm, even more preferably equal to 300 rpm.
• the treatment method includes a step to apply the treatment solution to the semimanufactured product to be treated, in particular to the surface destined to come into contact with the skin of the end user.
• the treatment solution is applied by spraying, preferably by means of compressed air guns.
• the spray pressure is preferably maintained between 0.4 and 0.7 atm. The use of these pressures ensures precision during application and also makes it possible to limit the phenomenon of bounce-back of the solution on the surface of the semimanufactured product. The quantity of treatment solution which is lost through bounce-back is therefore extremely low, to the advantage of production economy.
• the treatment solution is sprayed through nozzles having a diameter between 0.5 and 1.3 mm, even more preferably equal to 0.8 mm.
• the treatment solution is applied at low pressure and high volume, with reference to the pressures and to the volumes which are normally used to treat leathers (for example, when applying dyes).
• the step to apply the treatment solution is performed automatically.
• the semimanufactured products are transported on a conveyor belt and, when each of them is in proximity of the spray guns, specific sensor means detect their presence in the correct position and then transmit suitable signals to a control processor which activates the spray guns, opening their nozzles.
• the step to apply the treatment solution takes place according to a plurality of successive application operations.
• the treatment solution is applied in four subsequent application operations, each applying between 40 and 60 grams of treatment solution per square metre of surface of the semimanufactured product.
• the quantity of treatment solution applied is equal to 50 grams per square metre of surface of the semimanufactured product.
• the treatment solution applied is therefore equal to 200 g per square metre of surface of semimanufactured product, which, according to a preferred embodiment, corresponds to 2 grams of granules of silver per square metre of semimanufactured product to be treated.
• the treatment method according to the invention also comprises a step to fix the treatment solution to the surface of the semimanufactured product.
• the fixing step has the purpose of insolubilizing the natural proteins of the binder solution, so as to make them swell less in water and thus obtain stability to wet treatments.
• the fixing step takes place according to a plurality of successive fixing operations.
• each application operation is followed by a fixing operation suitable to fix the treatment solution applied in the specific application operation to the surface of the semimanufactured product.
• the fixing operations are also four in number, each following one of the four application operations described previously.
• each of the fixing operations comprises the application of a fixing substance to the surface of the semimanufactured product (to which the treatment solution has previously been applied).
• the fixing substance contains aldehydes suitable for crosslinking the natural proteins of the binder solution (and of the treatment solution).
• the fixing substance contains glyoxal, which is suitable for crosslinking casein. Glyoxal is preferably included in the fixing substance in a percentage between 3% and 5%.
• the method according to the invention comprises a step to dry the semimanufactured product.
• the drying step preferably includes a plurality of drying operations.
• the drying step includes a plurality of drying operations, each of which is performed subsequently to respective application operations, and a plurality of drying operations, each of which is performed subsequently to respective operations to fix the treatment solution on the semimanufactured product.
• the single drying operations can be implemented by placing the semimanufactured product in an environment which has a predetermined drying temperature, for example in a drying oven.
• the drying temperature is preferably between 30°C and 50°C, even more preferably equal to 40°C.
• the time of the drying operations preferably varies from 20 to 40 seconds.
• the times of the drying operations are selected so that the operations to apply the treatment solution take place on the dry leather, while the fixing operations take place on the leather while it is still, albeit slightly, damp. In fact, in this manner the fixing substance is made to act in depth, instead of only on the outer surface of the leather.
• the drying operations subsequent to the application operations preferably have a duration of 20 seconds, while the drying operations subsequent to the fixing operations preferably have a duration of 40 seconds.
• the method according to the invention also comprises a final buffing step.
• This buffing step can, for example, be obtained through hot stretching using heated rollers that press the semimanufactured product on the treated side. This process allows a leather with a high level of smoothness and shine to be obtained.
• the semimanufactured product treated according to the procedures described can advantageously be used to manufacture a particular item, such as an article of clothing, footwear, a watchstrap, a small leather article (wallet, purse), a covering for objects (for eyewear, for seats).
• a particular item such as an article of clothing, footwear, a watchstrap, a small leather article (wallet, purse), a covering for objects (for eyewear, for seats).
• the leather of the shoe Due to the treatment to which the semimanufactured product is subjected, based on an aqueous binder solution, the leather of the shoe is soft and elastic, as well as sufficiently breathable. Moreover, the presence of the granules of silver limits the production of unpleasant odours linked to perspiration of the foot due to the antiseptic, antibacterial and odour-preventing action of the silver dispersed on the internal surface of the shoe.
• the leather As treatment of the semimanufactured product is performed using an aqueous solution without pigments and dyes, the leather has an extremely natural appearance.
• aqueous binder solution especially when applied to leather, provides products with a high level of permeability to perspiration and the capacity to limit the occurrence of unpleasant odours.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Treatment And Processing Of Natural Fur Or Leather (AREA)
• Treatment Of Fiber Materials (AREA)
• Application Of Or Painting With Fluid Materials (AREA)

Applications Claiming Priority (1)

Publications (2)

Family

ID=42224942

Family Applications (1)

Country Status (12)

Families Citing this family (4)

Family Cites Families (6)

• 2009
  • 2009-01-10 UA UAA201205171A patent/UA100959C2/uk unknown
  • 2009-10-01 BR BR112012006726A patent/BR112012006726B1/pt not_active IP Right Cessation
  • 2009-10-01 WO PCT/IT2009/000445 patent/WO2011039786A1/en active Application Filing
  • 2009-10-01 CN CN200980161785.8A patent/CN102575302B/zh not_active Expired - Fee Related
  • 2009-10-01 ES ES09764312.6T patent/ES2445095T3/es active Active
  • 2009-10-01 MX MX2012002941A patent/MX2012002941A/es active IP Right Grant
  • 2009-10-01 EP EP09764312.6A patent/EP2483430B1/en not_active Not-in-force
• 2010
  • 2010-09-26 SA SA110310720A patent/SA110310720B1/ar unknown
  • 2010-09-29 AR ARP100103550A patent/AR080609A1/es active IP Right Grant
• 2012
  • 2012-03-19 TN TNP2012000120A patent/TN2012000120A1/en unknown
  • 2012-10-19 HK HK12110410.7A patent/HK1169684A1/zh not_active IP Right Cessation
• 2014
  • 2014-02-10 HR HRP20140127AT patent/HRP20140127T1/hr unknown

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