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
  • C14C3/02—Chemical tanning
  • C14C3/08—Chemical tanning by organic agents
• • 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 untanned hides, biologically stable, in wet form, also called B.S.H. ("White Stabilized Wet").
• skins can come in different forms: - unprocessed (salted, brined, salted-dry and fresh ...) - in the pickled state (treatment with a strong acid solution in the presence of salt) - in the tanned state (notably "wet-blue” chrome treatment) - in the semi-worked state (stain) - or in the finished state.
• the skins in the raw state present, according to their presentation problems of salt pollution, rewetting .... As for pickled skins, they are fragile because they have not undergone chemical treatment and must be protected against swelling.
• the leather industry has been interested in new products constituting an intermediate phase of preconditioning the skins after pickling; these have several advantages: - they are free of chromium - they are likely to withstand the operations of slitting and shoring (intended to produce leathers for different markets) before the tanning operations; these ripping and deraying operations carried out on these new products therefore make it possible to avoid the production of chrome-plated solid waste. - the defects existing in the skins can be detected very early in the leather transformation sector, which allows a better choice and a better orientation of the skins according to their quality and market needs.
• the subject of the present invention is moist, colorless, biologically stable, untanned skins, completely free of chromium, containing from 50 to 70%, preferably from 55 to 65% by weight of water, from 5 to 30%, preferably from 7 to 12%, by weight of total mineral matter relative to dry leather and degreased, from 0.5 to 1.5%, preferably less than 1%, by weight of Al2O3 relative to dry and degreased leather and from 85 to 90% by weight of dermal substance relative to dry and degreased leather, wet skin characterized in that it is intrinsically insensitive to mold without the addition of complementary fungistatic and bacteriostatic agents.
• the BSHs of the invention can be obtained by impregnation at a pH of the order of 3 to 4, preferably of the order of 3.5 to 3.8, of pickled skins, using a base of basic aluminum polychloride or of basic aluminum polychlorosulfate in an amount corresponding to 0.08 to 0.45%, preferably 0.10 to 0.25% by weight of Al2O3 relative to the weight of the skin in guts, then basification to a final pH of the order of 4 to 4.4 and possibly wringing.
• the pickled skins used come from various animal species such as sheep, goats, cattle ... and obtained by pickling according to the usual methods of pickling skins that have undergone the classic river operations (revegetation, depilation, deliming, confectionery ).
• the impregnation operation can be carried out at ordinary temperature (10 to 35 ° C. for example) in a fulling drum with adjustable speed of rotation with the possibility of reheating the impregnation bath.
• the basification operation is then carried out for example using bicarbonate or sodium carbonate, magnesium oxide, dolomites ... in sufficient quantity to obtain a pH of the bath of the order of 4 to 4 , 4.
• the product obtained is not very sensitive to molds, without the addition of fungistatic or bacteriostatic agents. So after 7 weeks of storage at 35 ° C, the B.S.H. of the invention still do not exhibit mold.
• a refinement of the impregnation operation makes it possible to prevent any accidental phenomenon of mold, consists in introducing into the treatment bath from 0.5 to 5% by weight relative to the weight of tripe of a vinyl acid such as methacrylic. , allylic and in particular acrylic and / or 0.02 to 1.25% by weight (expressed as oxide) relative to the tripe weight of one of their metal salts (rare earths of the lanthanum, cerium type; zinc, nickel ...) and in particular lanthanum acrylate.
• vinyl acids or their salts can be eliminated or transformed for the subsequent use of waste, by polymerization using an oxidation-reduction couple, X-rays, etc.
• the usual antifungal agents in the treatment of skin can also be introduced into the impregnation bath (derivatives of chlorinated phenols, benzothiazoles, isothiazolones).
• the B.S.H. of the invention have particularly good rewettability properties, which make it possible in particular in the case of small skins (goats, sheep) not to use a rewetting agent (surfactants of the sulfonate type, amines, amine salts. ..) for their transformation into BSS dry stabilized skin
• a rewetting agent surfactants of the sulfonate type, amines, amine salts. ..
• the B.S.H. of the invention are simply introduced for rewetting in a fuller in the presence of water with minimum mechanical work so as not to damage the skins by abrasion.
• the B.S.H. of the invention is easily reversible; in fact, it can be transformed back into raw skin by acid treatment in a fuller (for example using an aqueous solution of hydrochloric, sulfuric acid, etc.) in order to remove the aluminum salts.
• the B.S.H. subject of the invention have a minimum shrinkage temperature of at least 60 ° C, generally of the order of 64 to 68 ° C, fully compatible with slitting and derayage operations.
• the B.S.H. can then undergo the conventional tanning operations: chrome tanning with better exhaustion of the chromium bath since the B.S.H. contains aluminum salts; synthetic tanning; vegetable tanning or combinations of these different types of tanning.
• Half-croupons of cows having undergone river operations are subjected to the pickling and stabilization operations according to the invention.
• the device used is an 800 liter wooden fuller with adjustable speed. The percentages mentioned are by weight and calculated on the weight of tripe unless otherwise indicated.
• the pH of the bath obtained is 3.4.
• Impregnation rotation speed 6 to 8 rpm 2% (ie 0.16% expressed as Al2O3) of aqueous aluminum polychlorosulfate solution having a basicity of 55%, a desulfation rate of 82% and an Al2 O3 content of 8.3% obtained are added to the bath. according to the process described in European patent application No. 218,487. The medium is rotated for 2 hours The pH of the bath obtained is 3.6.
• the BSH wringed contains - 60% of its weight of water - 10% of its weight (relative to the dry matter according to standard NF-G 52 202) of mineral matter. - 0.80% of its weight (relative to the dry matter) of Al2O3 - 85% of its weight (relative to the dry matter) of dermal substances.
• Tanning rotation speed from 8 to 10 rpm 8% chromium sulphate is added to the bath in the form of a 25% aqueous solution - rotation: 6 hours
• the pH of the bath obtained is from 3.2 to 3.3.
• Basification rotation speed 8 to 10 rpm
• Basification rotation speed 8 to 10 rpm
• the wet-blue obtained are unloaded and placed on an easel.
• the stains obtained are unloaded and placed on the easel for 24 hours.
• the product obtained contains 0.132% of fixed Al2O3 (expressed relative to the dry matter).
• the B.S.H. contained 0.80% of Al2O3 expressed in relation to the dry matter.
• Example 2 The pickling, impregnation and basification operations described in Example 1 are repeated, carrying out the impregnation operation using 2.2% aqueous solution of basic aluminum polychlorosulfate.

Landscapes

• 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)
• Compositions Of Macromolecular Compounds (AREA)
• Chemical And Physical Treatments For Wood And The Like (AREA)
• Reinforced Plastic Materials (AREA)

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• 1989
  • 1989-07-28 FR FR898910193A patent/FR2650293B1/fr not_active Expired - Fee Related
• 1990
  • 1990-07-23 NZ NZ234622A patent/NZ234622A/xx unknown
  • 1990-07-23 EP EP90402109A patent/EP0411986A1/fr not_active Withdrawn
  • 1990-07-25 CN CN90107247A patent/CN1049525A/zh active Pending
  • 1990-07-26 AU AU59840/90A patent/AU631229B2/en not_active Ceased
  • 1990-07-26 NO NO90903321A patent/NO903321L/no unknown
  • 1990-07-26 ZA ZA905880A patent/ZA905880B/xx unknown
  • 1990-07-26 MA MA22187A patent/MA21917A1/fr unknown
  • 1990-07-26 IL IL95194A patent/IL95194A0/xx unknown
  • 1990-07-26 CA CA002022044A patent/CA2022044A1/fr not_active Abandoned
  • 1990-07-27 RU SU904830679A patent/RU1836429C/ru active
  • 1990-07-27 TN TNTNSN90107A patent/TNSN90107A1/fr unknown
  • 1990-07-27 JP JP2198106A patent/JPH03115499A/ja active Pending
  • 1990-07-27 HU HU904673A patent/HU210155B/hu not_active IP Right Cessation
  • 1990-07-27 PT PT94840A patent/PT94840A/pt not_active Application Discontinuation
  • 1990-07-27 IE IE273690A patent/IE902736A1/en not_active Application Discontinuation
  • 1990-07-27 DD DD90343107A patent/DD296706A5/de not_active IP Right Cessation
  • 1990-07-27 FI FI903774A patent/FI903774A0/fi not_active IP Right Cessation
  • 1990-07-27 BR BR909003681A patent/BR9003681A/pt not_active Application Discontinuation
  • 1990-07-27 RO RO145638A patent/RO109557B1/ro unknown
  • 1990-07-28 KR KR1019900011762A patent/KR910003118A/ko not_active Application Discontinuation
  • 1990-07-30 US US07/559,337 patent/US5147693A/en not_active Expired - Fee Related

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