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
  • C14C3/18—Chemical tanning by organic agents using polycondensation products or precursors thereof
• • 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
  • C14C3/26—Chemical tanning by organic agents using other organic substances, containing halogen
• • 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
  • C14C3/28—Multi-step processes
• • 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 concerns a low environmental impact and low toxicity process (therefore, compatible from the ecological point of view and with relation to health) to realize an "ecological" hide, that is a hide completely free of undesired toxic effects (such as, just as a way of non-limiting example, allergic reactions, inflammations, skin irritations, and so on), both on the workers at the productive process and on the consumers, that is the purchasers/users of the finished product.
• an "ecological" hide that is a hide completely free of undesired toxic effects (such as, just as a way of non-limiting example, allergic reactions, inflammations, skin irritations, and so on)
• the present invention concerns also the hide realized with said process.
• the traditional tanning processes commonly applied in the sector comprise, among others, three indispensable/necessary manufacturing phases (in the present document briefly indicated with the term “ steps ”) that are distinguished by their hazardousness, toxicity and polluting action also in the long term.
• steps commonly known in the field as “Pickle”, “Tanning”, and “Re-tanning”.
• the first of these steps (designated in the sector as Pickle [or " Pickling "]) consists of the preparation of the hides for the subsequent phase of effective tanning by means of the treatment of the same with a robust mixture of salts (for example, sodium chloride and sulfate), of strong acids (such as organic acids, for example, formic acid, and inorganic acids, for example sulfuric acid) at rather low pH values (of about 2,5), and of the so-called pickling agents, such as, for example, naphthalenesulfonic acid (employed to reduce a part of HCOOH and of H 2 SO 4 ).
• salts for example, sodium chloride and sulfate
• strong acids such as organic acids, for example, formic acid, and inorganic acids, for example sulfuric acid
• pickling agents such as, for example, naphthalenesulfonic acid (employed to reduce a part of HCOOH and of H 2 SO 4 ).
• the second of these steps (designated in the sector as Tanning) consists of the treatment of hides, pretreated in the above-mentioned Pickle phase, with heavy metals mixtures (in particular, chromium salts, aluminum, iron, zirconium and titanium, among the most common ones); aldehydes, for example, formaldehyde, glutaric dialdehyde; syntans, that can contain very high formaldehyde values, vegetable tannins (that carry the C.O.D.
• heavy metals mixtures in particular, chromium salts, aluminum, iron, zirconium and titanium, among the most common ones
• aldehydes for example, formaldehyde, glutaric dialdehyde
• syntans that can contain very high formaldehyde values
• vegetable tannins that carry the C.O.D.
• the third of these steps basically consists of a first further treatment, for a whole night, of the hides, obtained from the preceding step of Tanning, with heavy metals (in particular Chromium salts), aldehydes , various additives, followed by, the next day, a second further treatment, the so-called anionic re-tannings, in the presence of rather toxic synthetic resins and/or anionic synthetic tannins.
• heavy metals in particular Chromium salts
• aldehydes various additives
• anionic re-tannings in the presence of rather toxic synthetic resins and/or anionic synthetic tannins.
• the hides obtained at the end of a traditional tanning process that comprises the indispensable passages of Pickle, Tanning and Re-Tanning as commonly known in the sector and as described above, still contain quantitatively and qualitatively significant residues of the toxic pollutants described above (in particular, the heavy metals), thus provoking a series of toxic effects (allergic reactions, skin irritations, inflammations and so on), both on the workers at the productive process, and on the users of the finished product.
• WO 2012/062413 describes a tanning process without metals and without the pickle phase based on halogenated sulfonated organic compounds.
• EP 2 415 879 A1 describes a tanning process without metals and without the Pickle phase based on aqueous compositions of compounds containing carbamoyl-sulfonate groups.
• the aim of the present invention is that of giving an adequate answer to the need mentioned above.
• the Applicant has studied diligently the problem previously described, taking into account both the Italian and Community laws concerning environmental anti-pollution and those laws relative to the low toxicity of the intermediate reactants and of the final products (that is, the hides) obtained and put in commerce.
• object of the present invention a productive process, of low environmental impact and low toxicity, to realize an ecological hide, that is without undesired toxic effects on the organism, free of the traditional steps of Pickle and Tanning, as indicated in the independent claim attached.
• the present invention refers to a process, of low toxicity and low environmental impact (both at short and long term), for the industrial preparation of ecological hide (that is, presenting the characteristics of complete non-toxicity, both for the manufacturing workers and for the final users), wherein said process is substantially characterized in that it is free of the two indispensable manufacturing steps of the known art (highly toxic and polluting) called Pickle and Tanning, as previously described, wherein said two steps are substituted by a single step (non-toxic or polluting), conventionally/for simplicity reasons designated by the Applicant in the present document as Pre-tanning.
• the process in accordance with the present invention is characterized in that it comprises one step, conventionally designated by the Applicant as Pre-tanning, and is also characterized by the absence of the indispensable standard steps of the known art commonly called Pickle and Tanning, described before.
• the process in accordance with the present invention is further characterized by the presence of one step, conventionally/for simplicity reasons designated by the Applicant in the present document as Re-tanning, wherein, unlike what is taught and applied in the known art, said step of Re-tanning of the present invention is made without employing the heavy metals and/or the other toxic substances commonly employed in the known art, but using an adequate selection of re-tannings based on known non-toxic natural products, as described below in the present description.
• the process in accordance with the present invention comprises or consists of, schematically, at least the following manufacturing phases:
• Said process is further characterized in that the step designated as Re-tanning of the present invention is carried out without employing the heavy metals and/or the other very toxic substances commonly employed in the known art, but using known tannings based on known non-toxic natural products, as described below in the present description.
• the hides as received from the provider (that is, conserved in sodium chloride sprinkled on the skin side and on the flesh side), are weighed and introduced into wooden "barrels", or made of inox steel, or of polypropylene, or of wood internally covered with polypropylene, of cylindrical shape.
• said barrels are preferably in polypropylene, or internally covered with polypropylene (the polypropylene does not absorb or release contaminant substances, unlike wooden and steel barrels).
• each step consists of appropriate barrel rotation times with introduction and emptying (into and from the same) of the products/reactants necessary to realize the step itself.
• step of Finishing of the PHASE III of the process of the invention which differs from the corresponding step of Finishing of the standard process of the state of the art precisely in the accurate selection of the reactants and of the toxicologically and ecologically most compatible products.
• the step (i) (Soaking) has the aim of re-giving the hides the water lost during the conservation (re-hydration); of cleaning the hide; and of removing the salt of conservation.
• step (i) it is normally made use of: various antibacterial agents, commonly known in the art, preferably, those based on organic sulfur compounds, with a pH of about 10 (for example, the product commercially available in Italy with the commercial name TRUPOSEPT ® BA; product of: Trumpler Italia S.P.A, IT, in a total concentration of about 0,6%); soaking enzymes commonly known in the art (for example, the product commercially available in Italy with the commercial name FORTRAN ® K-225; product of: KEMIA TAU s.a.s La Cassa TORINO, in a total concentration of about 1%); salts with alkaline reaction, such as hydroxides, bicarbonates or carbonates (for example, sodium carbonates in an overall concentration of about 0,9% and sodium hydroxide in an overall concentration of about 0,3%); detergents commonly known in the art (for example, the product commercially available in Italy as ALYSOL LDG; product of: POLYCOLOR s.r.l.
• various antibacterial agents commonly known in the art
• the step (i) comprises one or more barrel rotation periods and terminates with a phase that, in technical terms, is conventionally defined as "Automatic by Night", during which the hides, into the barrel, suffers rotation periods followed by rest periods. In general, the barrel makes some minutes of rotation followed by sixty minutes of rest; all this is automatized for a working cycle of about twelve hours, preferably carried out during the night (hence the name).
• the step (ii) (Liming) has the purpose of solubilizing the globular proteins, of saponifying the natural fats, of destroying the skin, of making the hide re-inflate in such a way as to obtain spaces between the fibers, which will be important for the subsequent fixation of the non-toxic tannings of the present invention.
• step (ii) use of the following is made: hydrated lime, known commercial anti-wrinkle agents (containing a part of organically-bound sulfur), reducing products such as commercial sodium sulphide (Na 2 S), at the 60/62%, with a content of S around the 24,6%, and the commercial sodium hydrogen sulphate (NaHS), at the 70/72%, with a content of S around the 40%.
• reducing products such as commercial sodium sulphide (Na 2 S), at the 60/62%, with a content of S around the 24,6%
• NaHS sodium hydrogen sulphate
• the hides are again weighed ( fleshed weight ) and introduced into the barrel to undergo the subsequent steps of de-liming and bating. From here onwards, as already anticipated, the percentages of the products/reactants used will be referred to the weight of the hides after the fleshing ( fleshed weight, as defined above).
• the step (iii) (De-liming) and the step (iv) (Bating) have, respectively, the aim of eliminating the lime used in the preceding step (ii) (making thus lower the pH of the hide from about 12,5 of final Liming to 7,5-8,5), and of completing the opening of the hide (already initiated in step (ii)), eliminating the elastic proteins that keep the fibers tight.
• mild delimings which are preferably constituted of organic salts based on buffered dicarboxylic acids, for a period of time comprised between about 40 min and 60 min, preferably, of 50 min.
• step (iv) use is made of bates based on proteolytic enzymes of pancreatic origin for a period of time comprised between about 50 min and 70 min, preferably, of 60 min. At the end, it is treated/rinsed with current water to lower the temperature of the bath and the pH (at about 7-7,5) in such a way as to inhibit the further enzymatic action.
• the PHASE I above is executed following substantially the process and the modalities of the standard tanning cycle, optimizing, according to the type of hide, the times, the selection and the amounts of the reactants (privileging those that are less toxic) and using the machinery known and commonly employed in the sector.
• Pre-tanning an intermediate step conventionally designated by the Applicant in the present document as Pre-tanning.
• Said step, so-called Pre-tanning is used in substitution of the necessary standard steps (highly toxic and polluting) of the state of the known art, commonly known as Pickle and Tanning.
• said step of Pre-tanning has the aim of preparing the hides for the subsequent operations, in the first place, for the mechanical operations of the "Pressing" and of the " ⁇ Shaving". Moreover, it has also allowed to increase advantageously the affinity of the hides and the chemical reactants selected for the manufacturing steps of the PHASE II (Re-tanning, Fatting and Dyeing), with respect to what has been obtained with the phases of Pickle and Tanning of the known art. Following this, it has been advantageously possible to reduce the manufacturing times and the amounts of the reactants of the subsequent steps, obtaining an unexpectedly saving also in terms of water and electric energy used, as already explained.
• the so-called step of Pre-tanning comprises the following manufacturing.
• an appropriate non-toxic amphoteric heterocyclic aromatic organic tanning agent is introduced into said barrel, having a pH similar to 6,5, free of metals, aldehydes, phenols (for example, the product commercially available in Italy as GRANOFIN ® F90; product patented by Clariant, based on a non-toxic halogenated heterocyclic aromatic derivative; product of CLARIANT Prodotti - ITALY, S.p.A) in an amount comprised between 5% and 20% by weight, with respect to the weight of the fleshed hides; preferably, between 8% and 12%, more preferably of about the 10%, applying a continuous barrel rotation for the whole night (about 12 hours).
• the bath is emptied and, after the drainage, water from 100% to 300% is introduced, preferably about the 200%, at a temperature comprised between 25°C and 35°C, preferably of 30°C, making the barrel rotate from 5 min to 15 min, preferably 10 min; after which the bath and the hides are discharged.
• the hides are piled and left at rest for about 24 hours; then, they preferably undergo three external mechanical treatments, well known and commonly applied in the sector, which are: the pressing, the shaving and the trimming (the pressing compresses the wet hide, stretching it appropriately; the shaving, made from 1 mm to 1,3 mm, preferably, from 1,1 mm to 1,2 mm, renders the thickness of the hide itself homogeneous; the trimming, last, eliminates a series of residues of shavings and of preceding manufacturing works).
• the operations above are carried out with modalities and apparatus well known an commonly used in the sector.
• the beginning of the PHASE II of the process of the present invention is preferably preceded by a brief phase of soaking or re-conditioning of the hides.
• Said brief phase of soaking/re-conditioning consists of putting the hides in water from 200% to 400%, preferably about the 300%, at a temperature comprised between 30°C and 40°C, preferably of 35°C, applying a barrel rotation time from 20 min to 40 min, preferably of 30 min; after which the barrel is emptied of the water.
• the step (v) of the present invention conventionally designated as Re-tanning by the Applicant, has unexpectedly resulted sufficient to substitute the traditional necessary steps of Tanning and Re-tanning of the known art (Scheme 1 above), advantageously completing the tanning process of the hides initiated in the preceding step, the so-called Pre-tanning, and, as it will result clear from the description below, is preferably made in conjunction with the step (vi) (Fatting).
• a filling agent preferably a proteic filler derived from the proteins of milk, at the 90%-95% of active substance (for example, the product commercially available in Italy with the commercial name MARACRYL ® SD emuls.
• the process goes on by adding, in the same bath, from 80% to 120%, preferably the 100%, of water at a temperature comprised between 40°C and 50°C, preferably of 45°C, and a mixture constituted of: a minimum amount, from 0,4% to 0,6%, preferably of 0,5%, of a metal sequestering agent, preferably an appropriate mixture of polyphosphates and of alkali metal salts, at the 96% of active substance (for example, the product commercially available in Italy with the commercial name UTANIT ® AF emuls.
• a metal sequestering agent preferably an appropriate mixture of polyphosphates and of alkali metal salts
• the draining of the hide is carried out, introducing into the barrel water from 100% to 300%, preferably 200%, at a temperature comprised between 45°C and 55°C, preferably 50°C, and applying a barrel rotation from 5 min to 15 min, preferably 10 min; after which the bath is emptied.
• the assembly of said components iii) and iv) constitutes the fattening component and gives softness to the touch to the final hide.
• water is introduced again into the barrel from 100% to 300%, preferably the 200%, at a temperature comprised between 25°C and 35°C, preferably of 30°C, and it is added, in the same bath, from 1% to 2%, preferably the 1,5%, of a complex of phosphonates and polyacrylates (for example, commercially available in Italy as CHELENE ® DSE emuls. 1:3; product of CLARIANT Prodotti S.p.A., ITALY; it serves to sequester the iron ions and the heavy ions, eventually still present, and to fix in the best way the preceding stage); and applying a rotation from 10 min and 30 min, preferably of 20 min; after which, the barrel is emptied and drained.
• a complex of phosphonates and polyacrylates for example, commercially available in Italy as CHELENE ® DSE emuls. 1:3; product of CLARIANT Prodotti S.p.A., ITALY; it serves to sequester the iron ions
• step (v) of Re-tanning of the present invention
• modest amounts of poorly toxic and poorly polluting reactants have been employed (significantly inferior to those used normally in the known art), thus contributing significantly to reduce advantageously the possible negative environmental impact of the process itself on the whole.
• Chart 1 Analysis of the residue waters of the baths of Tanning, Pre-tanning and Re-tanning of the standard processes of the state of the art and of the invention
• Bath A Bath B) Bath C) Bath D) Bath E) * Residue Value found (Internal method) [mg/L] Chromium 3.243,67 2.688,46 116 0,023 0,28 Cadmium ⁇ 0,01 ⁇ 0,01 ⁇ 0,01 0,0007 0,0030 Zirconium 1,0 ⁇ 0,01 1,53 0,011 0,048 Manganese 2,26 1,25 1,24 0,19 -- Copper 0,12 0,09 0,85 0,029 0,26 Pond 1,58 4, 96 3,60 ⁇ 0,0001 ⁇ 0,0001
• B) from the step of Re-tanning (night) of the state of the art (Scheme 1)
• C) from step of Re-tanning (morning) of the state of the art (Scheme 1)
• step (v) Re-tanning
• step (vii) the PHASE II of the process of the present invention foresees the realization of the phase (vii) (Dyeing) of the hides. Also in this step (vii) (Dyeing) the maximum care has been placed in the selection of the more natural and less toxic dyes in order to improve the environmental impact and the toxicity of the process of the invention.
• step (vii) (Dyeing)
• into the barrel water is introduced from 40% to 60%, preferably the 50%, at a temperature comprised between 25°C and 35°C, preferably of 30°C, with a barrel rotation from 5 min to 15 mien, preferably of 10 min; after which, the desired mixture of dyes is added (preferably synthesis acid dyes that bind on the hides, derivatives of food dyes and substantially free of metals), appropriately dosed and in the necessary concentration to obtain the tone of color that wants to be reached, applying a barrel rotation from 50 min to 70 min, preferably of 60 min.
• this phase of dyeing it is added, in the same bath, from 150% to 250%, preferably the 200%, of water at a temperature comprised between 45°C and 55°C, preferably of 50°C, with a barrel rotation from 5 min to 15 min, preferably of 10 min; then formic acid diluted 1:10 is added slowly (generally in a period of time that goes from 15 min to 25 min) up to reaching a value of pH comprised between 3,7 and 4, preferably of 3,8-3,9, applying then a barrel rotation from 50 min to 70 min, preferably of 60 min.
• the bath is drained, then water is re-introduced from 100% to 300%, preferably the 200%, at a temperature comprised between 25°C and 35°C, preferably of 30°C, and from 0,8% to 1,2%, preferably the 1%, of sodium formate in powder to remove the residue acidity, and applying a barrel rotation from 15 min to 25 min, preferably of 20 min.
• the bath is drained, after which water is still introduced into the barrel from 100% to 300%, preferably the 200%, between 25°C and 35°C, preferably at 30°C, and then from 0,8% to 1,2%, preferably the 1%, of the product CHELENE DSE dil.
• Said step (viii) (Finishing) is executed on the dried hides and has the aim of improving and also of giving a particular protection to the grain side of the hide (sometimes also to the flesh side), through applications of substances (appropriately selected among those known provided with low or no toxicity), which determine the realization of a surface film, thus giving a particular aesthetic aspect apart from the desired softness features.
• Said step of Finishing consists of a series of operations (mechanical and not) known and commonly applied in the sector.
• said phases are selected from the following:
• the undercoat consists of a mixture constituted of: from 40 pp to 80 pp, preferably from 50 to 70 pp, of organic and/or inorganic-based pigments in water with solids at the 35% (for example, the products commercially available in Italy as PIGMENTI TELAFIN; products of LMF BIOKIMICA S.p.A., Santa Croce Sull'Arno, PI); from 80 pp to 100 pp, preferably 90 pp, of a casein binder and polyamide in water with solids at the 14% (for example, the product commercially available in Italy with the commercial name PROTAN ® LP 3150; product of LMF BIOKIMICA S.p.A., Santa Croce Sull'Arno, PI); from 10 pp to 30 pp, preferably 20 pp, of condensed starch with fat acids, with solids at the 19% (for example, the product commercially available in Italy with the commercial name
• step of Finishing of the process of the present invention taken into consideration together with the other steps of said process, represents a further characterizing aspect of the process itself, with respect to the standard processes commonly applied in the tanning art.
• the hides obtained with the process according to the invention have shown to present characteristics that can be absolutely compared (and are also often better) to those of analogous hides realized with the standard processes commonly employed in the sector. Moreover, they have shown to contain only minimum amounts (on the whole non toxic or polluting) of residue products deriving from the manufacturing, as illustrated in the examples, though not-limiting, of the following Chart 2.
• the process of the present invention has revealed of low environmental impact and substantially free of toxicity.
• said process has unexpectedly allowed to obtain a final hide having optimal characteristics with regard to aesthetics, softness, brightness, homogeneity of the dye and elasticity, absolutely not inferior to those of the hides obtained with the traditional tanning processes.
• the hide realized with the process of the present invention can, eventually, contain only traces of chromium and/or of other metals (substantially deriving from the machineries of metal with which the hides are manufactured), of formaldehyde, of phenols, of phthalates, in a not significant amount from the point of view of the toxicity and of the eco-compatibility, thus resulting a low environmental impact product as well and, above all, absolutely non toxic or allergenic.

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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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Citations (4)

• 2013
  • 2013-04-02 IT IT000073A patent/ITFI20130073A1/it unknown
• 2014
  • 2014-04-02 EP EP20140163245 patent/EP2787086A1/de not_active Withdrawn

Patent Citations (4)

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