EP3286342A1 - Skins tanning process - Google Patents

Skins tanning process

Info

Publication number
EP3286342A1
EP3286342A1 EP16723529.0A EP16723529A EP3286342A1 EP 3286342 A1 EP3286342 A1 EP 3286342A1 EP 16723529 A EP16723529 A EP 16723529A EP 3286342 A1 EP3286342 A1 EP 3286342A1
Authority
EP
European Patent Office
Prior art keywords
tanning
skins
drum
retanning
process according
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP16723529.0A
Other languages
German (de)
French (fr)
Other versions
EP3286342B1 (en
Inventor
Fabrizio NICOLETTI
Andrea Piazza
Ludovico MASSIGNAN
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Osmo Srl
Original Assignee
Osmo Srl
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Osmo Srl filed Critical Osmo Srl
Publication of EP3286342A1 publication Critical patent/EP3286342A1/en
Application granted granted Critical
Publication of EP3286342B1 publication Critical patent/EP3286342B1/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

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
    • C14C3/16—Chemical tanning by organic agents using aliphatic aldehydes
    • 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
    • C14C3/20—Chemical tanning by organic agents using polycondensation products or precursors thereof sulfonated
    • 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
    • C14C3/22—Chemical tanning by organic agents using polymerisation products
    • 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 relates to a skins tanning process.
  • a tanning process includes preliminary operations producing the so-called pelt; the actual tanning; the retanning; and dressing treatments.
  • Preliminary operations are basically aimed at removing, from the skins, various impurities and the preservatives used to maintain the skins intact until the tanning process as well as at restoring the features of the skins, thus making them suitable for the following actual tanning treatments.
  • the skins are then subjected to dressing operations, even based on the uses for which the skins are intended.
  • the object of the present invention is to provide a tanning process that is not affected by the above-mentioned drawbacks shown by prior art processes; in particular, it is an object of the present invention to provide a tanning process that allows manufacturers to obtain a fully biodegradable product, besides being versatile and effective, which leads to the production of high-quality products .
  • the present invention relates to a tanning process as defined, in its essential aspects, in appended claim 1 and, in its additional features, in the dependent claims .
  • the process according to the present invention thanks to the specific products used and to the processing techniques applied, allows manufacturers to obtain a fully biodegradable product.
  • the process according to the present invention allows the skins to gain (after having been dried) features that are comparable with the ones obtained with traditional techniques, in particular softness, a peasant feel, colouring and technical performances that are suitable for the use in different fields, such as shoes, leather products, furniture, car upholstery, etc.
  • - figure 1 contains a table (Table I) showing examples of the ways in which a preliminary step, in particular a soaking-liming step, of the process according to the invention can be carried out;
  • - figure 2 contains a table (Table II) showing examples of the ways in which further steps, defining - as a whole - a tanning macro-step, of the process according to the invention can be carried out;
  • the process according to the invention is advantageously carried out in drums, for example in the ways (processing recipes) shown, by way of example, in the appended tables.
  • a rotary drum which is manually or semi-manually operated or is controlled by a control unit, which automatically manages, based on operating schedules corresponding to pre-set recipes, the operation of the drum and, therefore, the different steps of the process.
  • the drum can be set so as to rotate for predetermined time intervals at the desired speed, if necessary alternating rest times (still drum) .
  • an indication such as "automatic cycle x-y-x" indicates that the drum rotates for periods of x minutes alternated with rest periods of y minutes .
  • the drum is drained, when the processing recipe requires to do so, through suitable openings.
  • the process according to the present invention is used to treat raw skins, for example skins that are freshly salted immediately after having flayed the animal.
  • Raw skins are firstly introduced into the drum for a preliminary soaking-liming step, during which, in substantially known ways, the first processing in preparation of the tanning is carried out, thus obtaining the so-called pelt (state of the skin at the end of the preliminary soaking-liming step) .
  • tanning macro-step (carried out, for example, in the ways shown in Table II of figure 2) , which comprises four main steps: deliming, bating, pickling, tanning .
  • compositions of the products used in the tanning macro-step are indicated as percentage of the weight of the pelt of the skin (weight of the material obtained from the preliminary step and destined to the tanning macro-step) .
  • the deliming step has the function of completely removing the lime absorbed by the skin during the preliminary soaking-liming step.
  • thioglycolic acid e.g.: COSMOCAL E
  • the skin undergoes a bating treatment, which basically consists in the removal of the so-called surface shield (residues of proteins, albumins, etc.) and of elastin.
  • the bating step can be carried out in basically known ways, through suitable degreasing substances and enzymes (as indicated, for example, in Table II) .
  • the skin is subjected to a pickling step, consisting in conditioning the skin at a highly acid pH below 4 and approximately ranging from 2.7 to 3.5, preferably around 3-3.2.
  • the pickling step is carried out with known products (basically, sodium chloride, formic acid and sulfuric acid) , but, according to the invention, it requires specific operating techniques, which ensure a particular balance among the content of water, salts and acids in the treatment bath contained in the drum, this condition being necessary to make sure that the subsequent addition of the tanning substance and the penetration into the section of the skin produce good results.
  • known products basicly, sodium chloride, formic acid and sulfuric acid
  • the drum After having emptied the drum from the water left by the previous step (bating) , the drum is filled with a bath containing :
  • the drum is caused to rotate for 10-20 minutes and then density of the bath is controlled to make sure that it ranges from 8 to 10 degrees Baume .
  • the result is a bath with a pH below 4 and approximately ranging from 2.7 to 3.5, preferably ranging from approximately 3 to 3.2.
  • the total content of water at the end of the pickling step (hence, before the tanning step) , starting from 25% of initial water and after the addition of the diluted acids, is approximately 40% +/- 5%.
  • the content of water at the beginning of the tanning step should range from 25% to 55%.
  • experiments have shown that a total water content below 25% or exceeding 55% slows down - or even completely blocks - the penetration of the tanning product and, therefore, the stability of the tanning itself.
  • a tanning product (2-10%) is added to the drum, which contains an acid naphthalene tannin, an acid phenolic tannin and sodium sulphate; and a synthetic ester (0.1-1.0%) .
  • the drum is rotated for 5 hours.
  • the skins are discharged from the drum without being washed (contrary to what normally happens in traditional tanning processes) .
  • This type of tanning allows manufacturers to obtain a partial stabilization of the skins, which can be stored after having been subjected to pressing (or, if necessary, complete drying), split, shaved and, at the end, sent to the retanning and drying steps .
  • the skins Once the skins have been split and/or shaved to obtain the desired thickness, they are reintroduced into drums, in which a retanning step is carried out so as to give to the skins (after the drying thereof) high softness, a peasant feel, colouring and technical performances that are useful in the production of articles such as shoes, leather products, furniture, car upholstery, etc.
  • the retanning step is carried out, for example, in the ways shown in Table III of figure 3, where (like in the description below) the compositions of the products used are indicated as percentage of the weight of the shaved skin (material ready for the retanning step) .
  • the retanning step is carried out using a retanning compound containing a C4-C6 linear di-aldehyde in an aqueous solution, wherein the di-aldehyde is available in quantity ranging from 1 to 15% of the weight of the treated skin.
  • the retanning compound is prepared by mixing (for example, through rotation in the drum for approximately 20 minutes) :
  • a fatliquor for example a synthetic oil mixed with deodorized sulphited fish oil (e.g.: COSMOFAT G) , rotating for 30 minutes; then a liquid tanning product (8-12%) is added, which contains sulphone-based synthetic tannins, in particular phenolsulphone-based and/or di-idroxy-diphenilsulphone- based (e.g.: COSMOWHITE SR) , rotating for 120 minutes.
  • the drum is rotated for periods of 3 minutes with rest intervals of 30 minutes for a whole night (8 hours) .
  • the drum is drained and two washing steps are carried out with 300% of hot water (40°C) .
  • a vegetable fatliquor for example a vegetable lecithin-based one (e.g.: COSMOFAT C) , rotating for 30 minutes;
  • a vegetable lecithin-based one e.g.: COSMOFAT C
  • a vegetable extract-base filler e.g.: COSMOWHITE F
  • COSMOWHITE F a vegetable extract-base filler
  • tanning product containing sulphone- based synthetic tannins e.g.: COSMOWHITE SR
  • COSMOWHITE SR sulphone- based synthetic tannins
  • the drum is drained and two further washing steps are carried out .
  • the skin is pressed, vacuum-dried at a temperature not exceeding 40 °C and then hung in a catenary for complete drying.
  • the skin Once the skin has dried, it can be processed to manufacture any kind of article.
  • the products used for the dressing of the skins must be selected so as not to jeopardize the biodegradability of the leather obtained with the process according to the invention .

Abstract

A skins tanning process comprises a tanning step and a retanning step; the tanning step comprises the steps of: treating the skin in a drum with a bath containing a tanning product comprising an acid naphthalene tannin, an acid phenolic tannin and sodium sulphate; and optionally a synthetic ester; and the retanning step comprises the steps of: treating the skin in a rotary drum with a retanning bath containing an aqueous solution of a di-aldehyde, in particular a C4-C6 linear di-aldehyde; adding a fatliquor; adding a liquid tanning product containing sulphone-based synthetic tannins, in particular phenolsulphone-based and/or di-idroxy-diphenilsulphone-based; adding a vegetal-base filler.

Description

"SKINS TANNING PROCESS"
TECHNICAL FIELD
The present invention relates to a skins tanning process.
BACKGROUND ART
Skins tanning, i.e. the processing undergone by animal skins to turn them into leather, in an ancient process, but nowadays it is carried out with advanced techniques.
Generally speaking, a tanning process includes preliminary operations producing the so-called pelt; the actual tanning; the retanning; and dressing treatments.
Preliminary operations are basically aimed at removing, from the skins, various impurities and the preservatives used to maintain the skins intact until the tanning process as well as at restoring the features of the skins, thus making them suitable for the following actual tanning treatments.
Then, tanning transforms the pelt into leather by means of proper tanning substances, which penetrate the skin and are steadily fixed to the dermal fibres. There are different types of tanning (vegetable tanning, mineral tanning, etc.), which differ from one another because of the tanning substances used and of the ways in which these substances are applied; some types of tanning are better than others for the treatment of certain skins and, generally speaking, manufacturers select the tanning process that is deemed to be the most appropriate to obtain specific features of the end product .
After the actual tanning there is a retanning step, which is used to define the specific features of the skins depending on the article to be manufactured; the skins are then subjected to dressing operations, even based on the uses for which the skins are intended.
Tanning processes known at the moment have proven to be not good enough, in particular from the point of view of their environmental impact. As a matter of fact, known processes, because of the products used in the different processing steps and of the techniques involved, cause the production of waste waters and of processing waste that are highly polluting and, anyway, are very difficult to be handled from an environmental point of view; moreover, they do not lead to an end product or to a processing waste that are completely (or at least largely) biodegradable or compostable.
DISCLOSURE OF INVENTION
The object of the present invention is to provide a tanning process that is not affected by the above-mentioned drawbacks shown by prior art processes; in particular, it is an object of the present invention to provide a tanning process that allows manufacturers to obtain a fully biodegradable product, besides being versatile and effective, which leads to the production of high-quality products .
Therefore, the present invention relates to a tanning process as defined, in its essential aspects, in appended claim 1 and, in its additional features, in the dependent claims .
The process according to the present invention, thanks to the specific products used and to the processing techniques applied, allows manufacturers to obtain a fully biodegradable product.
Furthermore, the process according to the present invention allows the skins to gain (after having been dried) features that are comparable with the ones obtained with traditional techniques, in particular softness, a peasant feel, colouring and technical performances that are suitable for the use in different fields, such as shoes, leather products, furniture, car upholstery, etc.
BRIEF DESCRIPTION OF THE DRAWINGS
Further features and advantages of the invention will be best understood upon perusal of the description of the following non-limiting embodiments, with reference to the accompanying figures, wherein:
- figure 1 contains a table (Table I) showing examples of the ways in which a preliminary step, in particular a soaking-liming step, of the process according to the invention can be carried out;
- figure 2 contains a table (Table II) showing examples of the ways in which further steps, defining - as a whole - a tanning macro-step, of the process according to the invention can be carried out;
- figure 3 contains a table (Table III) showing examples of the ways in which a retanning step of the process according to the invention can be carried out.
BEST MODE FOR CARRYING OUT THE INVENTION
The process according to the invention is advantageously carried out in drums, for example in the ways (processing recipes) shown, by way of example, in the appended tables.
Advantageously, all operations are carried out in a rotary drum, which is manually or semi-manually operated or is controlled by a control unit, which automatically manages, based on operating schedules corresponding to pre-set recipes, the operation of the drum and, therefore, the different steps of the process.
For example, the drum can be set so as to rotate for predetermined time intervals at the desired speed, if necessary alternating rest times (still drum) .
In the appended tables, an indication such as "automatic cycle x-y-x" indicates that the drum rotates for periods of x minutes alternated with rest periods of y minutes .
Obviously, the indications provided below and contained in the appended tables must be interpreted as merely explanatory and the operating modes of the process, in particular the products used, their quantity and the duration of the single operations and steps, can be different from the ones shown.
The drum is drained, when the processing recipe requires to do so, through suitable openings.
The process according to the present invention is used to treat raw skins, for example skins that are freshly salted immediately after having flayed the animal.
Raw skins are firstly introduced into the drum for a preliminary soaking-liming step, during which, in substantially known ways, the first processing in preparation of the tanning is carried out, thus obtaining the so-called pelt (state of the skin at the end of the preliminary soaking-liming step) .
By mere way of example, the preliminary step is carried out in the ways shown in appended Table I of figure 1 (where the compositions of the products used are indicated as percentage of the weight of the raw skin treated in the preliminary step) . Here and below (and in all tables), the commercial names of the products used are provided by mere way of example; each product indicated herein can be replaced with equivalent products.
Then, there is a tanning macro-step (carried out, for example, in the ways shown in Table II of figure 2) , which comprises four main steps: deliming, bating, pickling, tanning .
In Table II and in the description below, the compositions of the products used in the tanning macro-step are indicated as percentage of the weight of the pelt of the skin (weight of the material obtained from the preliminary step and destined to the tanning macro-step) .
The deliming step has the function of completely removing the lime absorbed by the skin during the preliminary soaking-liming step.
According to the invention, it is important that the lime is completely removed.
In the deliming step, at first, a first bath is used, which contains:
- 50-100% cold water;
- 0.1-0.5% ammonium sulfate;
- 0.1-1.0% thioglycolic acid (e.g.: COSMOCAL E) .
The drum is caused to rotate for 15-45 minutes, then it is drained. Subsequently, after having drained the drum, (cold) water is added, in particular 30-100%; then, in successive stages, a deliming agent is added, in particular a sulfamic acid-based deliming agent (e.g.: DECALCINANTE A-OS SPECIAL), in increasing quantities:
- 0.5-2.0%, preferably approximately 1.0%, rotating for 15-45 minutes (for example, 30 minutes);
- 0.5-3.0%, preferably approximately 1.5%, rotating for 15-45 minutes (for example, 30 minutes);
- 1.0-5.0%, preferably approximately 3.0%, rotating for
120-240 minutes (for example, 180 minutes);
The drum is drained and a delimed skin is obtained, which is completely free from lime.
After having been delimed, the skin undergoes a bating treatment, which basically consists in the removal of the so-called surface shield (residues of proteins, albumins, etc.) and of elastin. The bating step can be carried out in basically known ways, through suitable degreasing substances and enzymes (as indicated, for example, in Table II) .
Subsequently, the skin is subjected to a pickling step, consisting in conditioning the skin at a highly acid pH below 4 and approximately ranging from 2.7 to 3.5, preferably around 3-3.2.
The pickling step is carried out with known products (basically, sodium chloride, formic acid and sulfuric acid) , but, according to the invention, it requires specific operating techniques, which ensure a particular balance among the content of water, salts and acids in the treatment bath contained in the drum, this condition being necessary to make sure that the subsequent addition of the tanning substance and the penetration into the section of the skin produce good results.
The pickling step is carried out as follows:
After having emptied the drum from the water left by the previous step (bating) , the drum is filled with a bath containing :
- 20-30% cold water;
- 4-10% sodium chloride;
- 0.3-0.7% sodium formate.
The drum is caused to rotate for 10-20 minutes and then density of the bath is controlled to make sure that it ranges from 8 to 10 degrees Baume .
Then there is the addition of:
- 1% formic acid at 85%, rotating for 30-60 minutes;
- 1% sulfuric acid at 98%, rotating for 3-4 hours. This is followed by a rest step lasting 12-24 hours, during which the drum rotates, for example, with cycles of 5-10 minutes alternated with pauses of 60-90 minutes.
The result is a bath with a pH below 4 and approximately ranging from 2.7 to 3.5, preferably ranging from approximately 3 to 3.2.
The total content of water at the end of the pickling step (hence, before the tanning step) , starting from 25% of initial water and after the addition of the diluted acids, is approximately 40% +/- 5%.
In any case, it is important to remember that the content of water at the beginning of the tanning step should range from 25% to 55%. As a matter of fact, experiments have shown that a total water content below 25% or exceeding 55% slows down - or even completely blocks - the penetration of the tanning product and, therefore, the stability of the tanning itself.
Then there is the actual tanning step, during which a tanning product (2-10%) is added to the drum, which contains an acid naphthalene tannin, an acid phenolic tannin and sodium sulphate; and a synthetic ester (0.1-1.0%) . The drum is rotated for 5 hours.
At the end of the tanning step, the skins are discharged from the drum without being washed (contrary to what normally happens in traditional tanning processes) .
This type of tanning allows manufacturers to obtain a partial stabilization of the skins, which can be stored after having been subjected to pressing (or, if necessary, complete drying), split, shaved and, at the end, sent to the retanning and drying steps . Once the skins have been split and/or shaved to obtain the desired thickness, they are reintroduced into drums, in which a retanning step is carried out so as to give to the skins (after the drying thereof) high softness, a peasant feel, colouring and technical performances that are useful in the production of articles such as shoes, leather products, furniture, car upholstery, etc.
The retanning step is carried out, for example, in the ways shown in Table III of figure 3, where (like in the description below) the compositions of the products used are indicated as percentage of the weight of the shaved skin (material ready for the retanning step) .
In particular, the retanning step is carried out using a retanning compound containing a C4-C6 linear di-aldehyde in an aqueous solution, wherein the di-aldehyde is available in quantity ranging from 1 to 15% of the weight of the treated skin.
For example, the retanning compound is prepared by mixing (for example, through rotation in the drum for approximately 20 minutes) :
- 150-250% hot water (at 40°);
- 1-15% of a C4-C6 linear di-aldehyde in an aqueous solution (e.g.: COSMOWHITE 58) .
Then the skins are introduced into the drum, which is rotated for 60 minutes. Subsequently, a fatliquor (8-12%) is added, for example a synthetic oil mixed with deodorized sulphited fish oil (e.g.: COSMOFAT G) , rotating for 30 minutes; then a liquid tanning product (8-12%) is added, which contains sulphone-based synthetic tannins, in particular phenolsulphone-based and/or di-idroxy-diphenilsulphone- based (e.g.: COSMOWHITE SR) , rotating for 120 minutes.
Then the drum is rotated for periods of 3 minutes with rest intervals of 30 minutes for a whole night (8 hours) .
The drum is drained and two washing steps are carried out with 300% of hot water (40°C) .
Then a bath of 100% hot water (40°C) is added, as well as a metal-free colouring agent, rotating for 30 minutes.
Subsequently, there is the addition of:
- 15-25% of a vegetable fatliquor, for example a vegetable lecithin-based one (e.g.: COSMOFAT C) , rotating for 30 minutes;
- 5-15% of an acrylic resin at 25% (e.g.: COSMOWHITE H) , rotating for 30 minutes;
- 5-15% of a vegetable extract-base filler (e.g.: COSMOWHITE F) , rotating for 120 minutes;
- 2-3% of formic acid, rotating for 30 minutes;
- 2-3% of formic acid, rotating for 30 minutes;
- 5-15% of the tanning product containing sulphone- based synthetic tannins (e.g.: COSMOWHITE SR) , rotating for 120 minutes .
The drum is drained and two further washing steps are carried out .
Subsequently, the skin is pressed, vacuum-dried at a temperature not exceeding 40 °C and then hung in a catenary for complete drying.
Once the skin has dried, it can be processed to manufacture any kind of article.
The products used for the dressing of the skins must be selected so as not to jeopardize the biodegradability of the leather obtained with the process according to the invention .
The process described and explained herein can be subjected to further changes and variants, which do not go beyond the scope of protection of the appended claims.

Claims

1. Tanning process, comprising a tanning step and a retanning step; the process being characterized in that the tanning step comprises the steps of: treating skins in a drum with a bath containing a tanning product comprising an acid naphthalene tannin, an acid phenolic tannin and sodium sulphate; and optionally a synthetic ester; and the retanning step comprises the steps of: treating the skins in a drum with a retanning bath containing an aqueous solution of a di-aldehyde, in particular a C4-C6 linear di-aldehyde; adding a fatliquor; adding a liquid tanning product containing sulphone-based synthetic tannins, in particular phenolsulphone-based and/or di-idroxy-diphenilsulphone- based; adding a vegetal-base filler.
2. A process according to claim 1, wherein the retanning step comprises then the steps of: draining the drum; effecting at least one and preferably two washes with water; optionally adding a coloring bath; adding a vegetal- base fatliquor; adding an acrylic resin; adding a vegetal- base filler; adding formic acid, in one or more times; adding a tanning product containing sulphone-base synthetic tannins; draining the drum; effecting at least one and preferably two more washes with water.
3. A process according to claim 1 or 2, wherein at the end of the tanning step the skins are discharged from the drum without being washed for being then subjected to the retanning step.
4. A process according to one of the preceding claims, comprising, before the tanning step, a step of deliming, performed so as to remove completely the lime that the skins have absorbed previously, in particular in a preliminary step of soaking-liming .
5. A process according to one of the preceding claims, comprising, before the tanning step, a pickling step, comprising the steps of: treating the skins in a drum with a bath containing sodium chloride and sodium formate, the bath having a density ranging between about 8 and about 10 degrees Baume; adding formic acid; adding sulfuric acid, for obtaining a bath having a pH lower than about 4 and approximately ranging between about 2,7 and about 3,5 and preferably ranging between about 3,0 and about 3,2.
6. A process according to one of the preceding claims, wherein the total water content at the end of the pickling step and before the tanning step is comprised between about 25% and about 55% of the pelt weight of the skins treated.
7. Tanned skin (i.e. leather), characterized by being obtained by the tanning process according to one of the preceding claims.
EP16723529.0A 2015-04-21 2016-04-21 Skins tanning process Active EP3286342B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ITTV2015A000055A ITTV20150055A1 (en) 2015-04-21 2015-04-21 SKIN TANNING PROCESS
PCT/IB2016/052282 WO2016170503A1 (en) 2015-04-21 2016-04-21 Skins tanning process

Publications (2)

Publication Number Publication Date
EP3286342A1 true EP3286342A1 (en) 2018-02-28
EP3286342B1 EP3286342B1 (en) 2021-07-28

Family

ID=53490121

Family Applications (1)

Application Number Title Priority Date Filing Date
EP16723529.0A Active EP3286342B1 (en) 2015-04-21 2016-04-21 Skins tanning process

Country Status (5)

Country Link
EP (1) EP3286342B1 (en)
CN (1) CN107743525B (en)
ES (1) ES2887790T3 (en)
IT (1) ITTV20150055A1 (en)
WO (1) WO2016170503A1 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106834563B (en) * 2017-01-20 2018-08-17 辽宁富新新材料有限公司 A method of few salt pickling, tanning leather
EP3844310B1 (en) * 2018-08-30 2023-10-18 Santori Pellami S.p.A. Metal-free tanning method
CN116397059A (en) * 2023-05-10 2023-07-07 顾家家居股份有限公司 Anti-odor composition for retanning of cowhide

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2834121C2 (en) * 1978-08-03 1980-08-21 Bayer Ag, 5090 Leverkusen Condensation products from terphenyl sulfonic acids, naphthalene sulfonic acids, bis (4-hydroxyphenyl) sulfone and formaldehyde
CN1208470C (en) * 2001-12-20 2005-06-29 单凯波 Processing method of making leather using frog skin
TW200641140A (en) * 2004-12-17 2006-12-01 Tfl Ledertechnik Gmbh Composition for the treatment of leather
DE102006029408A1 (en) * 2006-06-23 2007-12-27 Lanxess Deutschland Gmbh Condensation products containing sulfonic or carboxylic acid groups and based on di-aldehyde and amino compounds, e.g. glutaraldehyde and melamine and-or urea, used for tanning leather and furs
CN102586505B (en) * 2012-01-13 2014-04-23 浙江中辉皮草有限公司 Circularly-tanning technology for chrome tanning liquor of sheep garment leather
CN103215391B (en) * 2013-04-23 2015-02-04 何裕华 Non-chromium leather tanning method

Also Published As

Publication number Publication date
CN107743525A (en) 2018-02-27
ES2887790T3 (en) 2021-12-27
WO2016170503A1 (en) 2016-10-27
EP3286342B1 (en) 2021-07-28
ITTV20150055A1 (en) 2016-10-21
CN107743525B (en) 2020-12-29

Similar Documents

Publication Publication Date Title
KR102230317B1 (en) Method for producing leather
EP3286342B1 (en) Skins tanning process
CN102405297B (en) Method for tanning animal skins
AU2008331353A1 (en) Method of preserving hides and skins
JP2009286993A (en) Animal skin tanning method using no heavy metal such as chromium or aldehyde tanning agent
KR950014924B1 (en) Non-chrome tanning process
CN109415774B (en) Method for producing leather
KR100489725B1 (en) The processing method of natural leather
JP4926138B2 (en) Split leather for automobile sheets and manufacturing method thereof
JP6484610B2 (en) Tanning method for obtaining leather
US2266448A (en) Process and products for deliming limed pelts
JP6525966B2 (en) Chrome tanning method
EP3844310B1 (en) Metal-free tanning method
KR101581949B1 (en) Manufacturing method of natural leather capable of low content of hexavalent chromium
DK3110978T3 (en) Method for tanning animal skins and thus tanned leather
US1268876A (en) Manufacture of leather.
US1378213A (en) Leather-making process
US351204A (en) Tanning process
JP2020531637A (en) How to lick animal skin
US690357A (en) Depilating process.
US680222A (en) Tanning compound.
CN116391049A (en) Retanning and fatliquoring composition comprising hemp oil derivatives
JPH0663000B2 (en) A method for producing tanned leather with a fine grained surface with a fine silver surface
JPH07150200A (en) Method of tanning hide of shark or the like and production of leather product
PL204914B1 (en) Method for the processing the sheepskins for the fur industry purposes

Legal Events

Date Code Title Description
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE

PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 20171024

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

AX Request for extension of the european patent

Extension state: BA ME

DAV Request for validation of the european patent (deleted)
DAX Request for extension of the european patent (deleted)
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: EXAMINATION IS IN PROGRESS

17Q First examination report despatched

Effective date: 20181114

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: EXAMINATION IS IN PROGRESS

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: GRANT OF PATENT IS INTENDED

INTG Intention to grant announced

Effective date: 20210226

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE PATENT HAS BEEN GRANTED

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

REG Reference to a national code

Ref country code: DE

Ref legal event code: R096

Ref document number: 602016061229

Country of ref document: DE

REG Reference to a national code

Ref country code: AT

Ref legal event code: REF

Ref document number: 1414796

Country of ref document: AT

Kind code of ref document: T

Effective date: 20210815

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

REG Reference to a national code

Ref country code: LT

Ref legal event code: MG9D

REG Reference to a national code

Ref country code: NL

Ref legal event code: MP

Effective date: 20210728

REG Reference to a national code

Ref country code: AT

Ref legal event code: MK05

Ref document number: 1414796

Country of ref document: AT

Kind code of ref document: T

Effective date: 20210728

REG Reference to a national code

Ref country code: ES

Ref legal event code: FG2A

Ref document number: 2887790

Country of ref document: ES

Kind code of ref document: T3

Effective date: 20211227

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: RS

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210728

Ref country code: SE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210728

Ref country code: PT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20211129

Ref country code: NL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210728

Ref country code: NO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20211028

Ref country code: FI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210728

Ref country code: HR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210728

Ref country code: LT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210728

Ref country code: BG

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20211028

Ref country code: AT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210728

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: PL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210728

Ref country code: LV

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210728

Ref country code: GR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20211029

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210728

REG Reference to a national code

Ref country code: DE

Ref legal event code: R097

Ref document number: 602016061229

Country of ref document: DE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SM

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210728

Ref country code: SK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210728

Ref country code: RO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210728

Ref country code: EE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210728

Ref country code: CZ

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210728

Ref country code: AL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210728

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed

Effective date: 20220429

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

REG Reference to a national code

Ref country code: BE

Ref legal event code: MM

Effective date: 20220430

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MC

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210728

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20220421

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20220430

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20220430

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20220430

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20220421

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: IT

Payment date: 20230407

Year of fee payment: 8

Ref country code: FR

Payment date: 20230421

Year of fee payment: 8

Ref country code: ES

Payment date: 20230510

Year of fee payment: 8

Ref country code: DE

Payment date: 20230427

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20230418

Year of fee payment: 8

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: HU

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT; INVALID AB INITIO

Effective date: 20160421

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210728

Ref country code: CY

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20210728