EP0339437A1 - Tanning process saving chromium - Google Patents
Tanning process saving chromium Download PDFInfo
- Publication number
- EP0339437A1 EP0339437A1 EP89106934A EP89106934A EP0339437A1 EP 0339437 A1 EP0339437 A1 EP 0339437A1 EP 89106934 A EP89106934 A EP 89106934A EP 89106934 A EP89106934 A EP 89106934A EP 0339437 A1 EP0339437 A1 EP 0339437A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- chromium
- tanning
- acid
- salts
- iii
- 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.)
- Withdrawn
Links
- 238000000034 method Methods 0.000 title claims abstract description 16
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 title description 25
- 239000011651 chromium Substances 0.000 title description 10
- 229910052804 chromium Inorganic materials 0.000 title description 9
- 239000002253 acid Substances 0.000 claims abstract description 25
- BFGKITSFLPAWGI-UHFFFAOYSA-N chromium(3+) Chemical class [Cr+3] BFGKITSFLPAWGI-UHFFFAOYSA-N 0.000 claims abstract description 25
- 239000000203 mixture Substances 0.000 claims abstract description 22
- 150000003839 salts Chemical class 0.000 claims abstract description 15
- 150000003628 tricarboxylic acids Chemical class 0.000 claims abstract description 12
- 125000003118 aryl group Chemical group 0.000 claims abstract description 11
- 206010000496 acne Diseases 0.000 claims description 14
- HHLFWLYXYJOTON-UHFFFAOYSA-N glyoxylic acid Chemical compound OC(=O)C=O HHLFWLYXYJOTON-UHFFFAOYSA-N 0.000 claims description 14
- 239000011230 binding agent Substances 0.000 claims description 12
- XNGIFLGASWRNHJ-UHFFFAOYSA-N phthalic acid Chemical compound OC(=O)C1=CC=CC=C1C(O)=O XNGIFLGASWRNHJ-UHFFFAOYSA-N 0.000 claims description 10
- 229910000514 dolomite Inorganic materials 0.000 claims description 8
- 239000010459 dolomite Substances 0.000 claims description 8
- -1 keto carboxylic acid Chemical class 0.000 claims description 7
- 150000001299 aldehydes Chemical class 0.000 claims description 5
- 229930194542 Keto Natural products 0.000 claims description 2
- HQWKKEIVHQXCPI-UHFFFAOYSA-L disodium;phthalate Chemical compound [Na+].[Na+].[O-]C(=O)C1=CC=CC=C1C([O-])=O HQWKKEIVHQXCPI-UHFFFAOYSA-L 0.000 claims 1
- 238000002203 pretreatment Methods 0.000 claims 1
- 239000000370 acceptor Substances 0.000 abstract 1
- QDOXWKRWXJOMAK-UHFFFAOYSA-N dichromium trioxide Chemical compound O=[Cr]O[Cr]=O QDOXWKRWXJOMAK-UHFFFAOYSA-N 0.000 description 30
- 235000002639 sodium chloride Nutrition 0.000 description 18
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 12
- 239000010985 leather Substances 0.000 description 10
- GRWVQDDAKZFPFI-UHFFFAOYSA-H chromium(III) sulfate Chemical compound [Cr+3].[Cr+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O GRWVQDDAKZFPFI-UHFFFAOYSA-H 0.000 description 9
- 239000003795 chemical substances by application Substances 0.000 description 8
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 7
- 150000007513 acids Chemical class 0.000 description 7
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 6
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 6
- 235000015217 chromium(III) sulphate Nutrition 0.000 description 5
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 4
- KKEYFWRCBNTPAC-UHFFFAOYSA-N Terephthalic acid Chemical compound OC(=O)C1=CC=C(C(O)=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-N 0.000 description 4
- 150000001844 chromium Chemical class 0.000 description 4
- QQVIHTHCMHWDBS-UHFFFAOYSA-N isophthalic acid Chemical compound OC(=O)C1=CC=CC(C(O)=O)=C1 QQVIHTHCMHWDBS-UHFFFAOYSA-N 0.000 description 4
- 239000000395 magnesium oxide Substances 0.000 description 4
- 239000011780 sodium chloride Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 description 3
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 3
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical class OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 description 3
- 150000001735 carboxylic acids Chemical class 0.000 description 3
- 235000019253 formic acid Nutrition 0.000 description 3
- 239000011833 salt mixture Substances 0.000 description 3
- 239000001648 tannin Substances 0.000 description 3
- 235000018553 tannin Nutrition 0.000 description 3
- 229920001864 tannin Polymers 0.000 description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- LCTONWCANYUPML-UHFFFAOYSA-N Pyruvic acid Chemical compound CC(=O)C(O)=O LCTONWCANYUPML-UHFFFAOYSA-N 0.000 description 2
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 2
- 229910052783 alkali metal Inorganic materials 0.000 description 2
- 125000004432 carbon atom Chemical group C* 0.000 description 2
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 2
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 2
- 229910000423 chromium oxide Inorganic materials 0.000 description 2
- 230000000873 masking effect Effects 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- 159000000000 sodium salts Chemical class 0.000 description 2
- GEHJYWRUCIMESM-UHFFFAOYSA-L sodium sulfite Chemical compound [Na+].[Na+].[O-]S([O-])=O GEHJYWRUCIMESM-UHFFFAOYSA-L 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- KDYFGRWQOYBRFD-UHFFFAOYSA-N succinic acid Chemical compound OC(=O)CCC(O)=O KDYFGRWQOYBRFD-UHFFFAOYSA-N 0.000 description 2
- 208000032544 Cicatrix Diseases 0.000 description 1
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 150000008064 anhydrides Chemical class 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 235000019606 astringent taste Nutrition 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 235000010216 calcium carbonate Nutrition 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 150000001732 carboxylic acid derivatives Chemical class 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- JOPOVCBBYLSVDA-UHFFFAOYSA-N chromium(6+) Chemical class [Cr+6] JOPOVCBBYLSVDA-UHFFFAOYSA-N 0.000 description 1
- 229910000356 chromium(III) sulfate Inorganic materials 0.000 description 1
- 239000011696 chromium(III) sulphate Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 125000005843 halogen group Chemical group 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 150000004715 keto acids Chemical class 0.000 description 1
- 239000001095 magnesium carbonate Substances 0.000 description 1
- 235000014380 magnesium carbonate Nutrition 0.000 description 1
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 1
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 235000010755 mineral Nutrition 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 150000002790 naphthalenes Chemical class 0.000 description 1
- 125000000449 nitro group Chemical group [O-][N+](*)=O 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 235000005985 organic acids Nutrition 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 125000002924 primary amino group Chemical group [H]N([H])* 0.000 description 1
- 229940107700 pyruvic acid Drugs 0.000 description 1
- 231100000241 scar Toxicity 0.000 description 1
- 230000037390 scarring Effects 0.000 description 1
- 230000037387 scars Effects 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 235000010265 sodium sulphite Nutrition 0.000 description 1
- RPACBEVZENYWOL-XFULWGLBSA-M sodium;(2r)-2-[6-(4-chlorophenoxy)hexyl]oxirane-2-carboxylate Chemical compound [Na+].C=1C=C(Cl)C=CC=1OCCCCCC[C@]1(C(=O)[O-])CO1 RPACBEVZENYWOL-XFULWGLBSA-M 0.000 description 1
- 239000001384 succinic acid Substances 0.000 description 1
- 125000000542 sulfonic acid group Chemical group 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
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
- C14C3/28—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
- C14C1/00—Chemical treatment prior to tanning
- C14C1/08—Deliming; Bating; Pickling; Degreasing
-
- C—CHEMISTRY; METALLURGY
- C14—SKINS; HIDES; PELTS; LEATHER
- C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
- C14C3/00—Tanning; Compositions for tanning
- C14C3/02—Chemical tanning
- C14C3/04—Mineral tanning
- C14C3/06—Mineral tanning using chromium compounds
Definitions
- Chrome tanning is an essential step in leather production.
- chromium salts are offered in a concentration which corresponds to an equivalent of 2 to 2.5% by weight of Cr 2 O 3, based on nakedness, in order to achieve a cookable leather. Of these, however, only 70 to 80% are actually permanently fixed in the skin, so that 20 to 30% of the chromium tannin offered ends up in the waste water.
- the level of chromium tanning can be improved.
- the increased astringency of the chrome tanning agents leads to scarring i.e. lower quality leathers. In most cases, a loss of space also has to be accepted.
- aromatic di- and tricarboxylic acids such as phthalic acid and / or their salts are used in pimples or in chrome tanning, to achieve a better fixation of the chromium in the skin. If they are used in the pimple, however, this leads to a significant reduction in the penetration speed of the subsequent chrome tanning agents, an uneven chrome distribution and, in the case of stronger, unsplit nakedness, even insufficient tanning in some cases.
- tanning must usually be carried out in two stages in order to reduce these deficiencies by using mild organic tanning which is carried out with mostly organically masked chromium (III) sulfate tanning agent and which is then carried out with the addition of aromatic di- and tricarboxylic acids follow alone or in the presence of further chrome tanning agent and / or a base agent.
- mild organic tanning which is carried out with mostly organically masked chromium (III) sulfate tanning agent and which is then carried out with the addition of aromatic di- and tricarboxylic acids follow alone or in the presence of further chrome tanning agent and / or a base agent.
- the invention relates to a process for chromium-saving tanning, in which the bosses are pretreated with 0.5 to 2% by weight, preferably 0.7 to 1.2% by weight, of an aldehyde or ketocarboxylic acid before the tanning Tanned and then tanned with 1 to 4.5% by weight, preferably 1 to 3% by weight, of a mixture of chromium (III) salts, acid-binding agents and aromatic di- or tricarboxylic acids or their salts.
- the preferred aldehyde or keto acid is glyoxylic acid, but also pyruvic acid.
- the pretreatment with these acids is carried out from an aqueous liquor with the above-mentioned concentrations. This pretreatment can be carried out separately, it is expedient to combine this pretreatment with these acids with the pimple.
- the combination with the pimple also has the advantage that the addition of the acids mentioned to the pimple eliminates the masking acids which are usually used there, such as formic acid or acetic acid.
- the pimple otherwise contains the usual acids and salts in the usual concentrations, for example 0.1 to 2% by weight sulfuric acid (90%). This pretreatment generally lasts 0.5 to 20 hours.
- the subsequent chrome tanning is carried out using the customary commercially available chromium (III) tannins according to the processes known per se.
- the chromium available, based on the pelt weight, is generally 0.8 to 1.5% by weight.
- the tanning time is approx. 30 to 180 minutes.
- chromium (III) salts for The tanning is suitable for the chrome (III) salts which are customarily used for chrome tanning, in particular chromium (III) sulfates, basic chromium (III) sulfates, and also with organic acids, for example formic acid, acetic acid, and chromium (III) salts masked , self-dulling chromium tanning agents which, in addition to chromium (III) salts, also contain inorganic salts, such as sodium sulfate, or reaction products of hexavalent chromium compounds with reducing agents.
- the tanning is carried out by treatment with an aqueous solution which contains chromium (III) salts, acid-binding agents and aromatic di- or tricarboxylic acids or their salts.
- the mixtures used for tanning preferably contain chromium sulfates and basic chromium sulfates as chromium (III) salts.
- Masked chromium (III) salts, in particular chromium (III) sulfates, which expediently only have a low degree of masking, can also be used.
- Suitable acid-binding agents are e.g. Dolomite, alkali carbonates and bicarbonates, alkaline earth carbonates and bicarbonates, magnesium oxide or sodium sulfite.
- the dolomite can be used either alone or in combination with other acid-binding substances, the dolomite content of the mixtures preferably being at least 10% of the total amount of acid-binding agents used.
- dolomite Mixtures containing 10 to 130% by weight of dolomite per 100% by weight of Cr2O3 are particularly suitable.
- the amount of dolomite to be used depends on the basicity of the chromium (III) salts used, and also on the basicity to which these chromium (III) compounds are to be made in the course of the tanning, on the basicity and the amount of those used in the preliminary tanning Chromium (III) salts and according to the amount of other acid-binding substances which may be used in the mixture.
- Aromatic dicarboxylic acids and tricarboxylic acids with 8 to 13 carbon atoms are those of the benzene and naphthalene series which, in addition to the carboxyl groups, can also contain hydroxyl, amino or nitro groups and / or halogen atoms. Phthalic acid and isophthalic acid are preferably used. Aromatic di- and tricarboxylic acids, which contain sulfonic acid groups in addition to the carboxyl groups, can only be used up to about a third of the total amount of carboxylic acid used.
- the carboxylic acids can expediently be used both in the form of the free acids, in the form of mixtures of the free acids and the salts of such carboxylic acids and also solely in the form of the salts, the alkali metal salts. Powdery mixtures of the free carboxylic acids and their salts in a molar ratio of 60:40 and 40:60 are preferably used.
- the tanning is expediently carried out in the same bath by adding the mixtures in powder form.
- the components of the claimed mixtures can preferably be added together. Only a few of these components can be added together, but also each individually.
- the basic chromium (III) salts are expediently added alone or together with further components. These chromium (III) salts can also be added together with the chromium (III) salts used for pretanning.
- the amounts of the mixtures to be used are such that the total amount of Cr2O3 offered in the pretanning and retanning is 1.2 to 2%, in particular 1.5 to 1.8% Cr2O3, based on the weight of the skin, and that the aromatic di - And / or tricarboxylic acids with 8-14 carbon atoms and / or their salts amount to at least 1.0 mole per mole of chromium oxide of the total chrome tanning agents used both for pretanning and for tanning.
- the tanning is carried out with a liquor in a liquor ratio of less than 100%, preferably 10 to 50%, based on the pelt weight, at temperatures of approx. 36-45 ° C.
- the tanning is carried out in such a way that at the end of the tanning the liquor has a pH of more than 3.6, in particular 3.9 to 4.5.
- the tanning process takes approximately 7 to 12 hours.
- the method of operation described above is particularly recommended for thinner nakedness.
- about 0.5 to 2.5% by weight, preferably 0.5 to 1.5% by weight, based on the nakedness, is used.
- the rest of this mixture about 1.5 to 2 wt .-%, is then used for tanning as described above. All of the operations described can be carried out in the same bathroom, but you can also work in several separate steps.
- the leather obtained by this process is cooked, soft, firm-grained, extremely fine-grained, easy to color with excellent physical properties and good yield.
- the chromium oxide content in the residual tannin liquor is extremely low.
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)
Abstract
Description
Die Chromgerbung ist ein wesentlicher Arbeitsschritt in der Lederherstellung. Bei herkömmlichen Verfahren werden zur Erzielung eines kochgaren Leders Chromsalze in einer Konzentration angeboten, die einem Äquivalent von 2 bis 2,5 Gew.-% Cr₂O₃ bezogen auf Blöße entsprechen. Hiervon werden jedoch nur 70 bis 80 % tatsächlich in der Haut dauerhaft fixiert, so daß 20 bis 30 % des angebotenen Chromgerbstoffs in das Abwasser gelangen.Chrome tanning is an essential step in leather production. In conventional methods, chromium salts are offered in a concentration which corresponds to an equivalent of 2 to 2.5% by weight of Cr 2 O 3, based on nakedness, in order to achieve a cookable leather. Of these, however, only 70 to 80% are actually permanently fixed in the skin, so that 20 to 30% of the chromium tannin offered ends up in the waste water.
Sowohl aus ökonomischen als auch ökologischen Gründen hat es daher in der Vergangenheit nicht an Versuchen gefehlt, die Chromfixierung in der Haut zu verbessern und die für eine kochgare Gerbung notwendige Chrommenge zu reduzieren.For economic and ecological reasons, there has been no shortage of attempts in the past to improve the chromium fixation in the skin and to reduce the amount of chromium required for cookable tanning.
So läßt sich durch Erhöhung des pH-Werts der Gerbflotte über das übliche Maß hinaus der Auszehrungsgrad der Chromgerbstoffe verbessern. Die gleichzeitig erhöhte Adstringenz der Chromgerbstoffe führt jedoch zu Narbenzug d.h. qualitativ minderwertigeren Ledern. Meist muß zusätzlich auch noch ein Flächenverlust in Kauf genommen werden.Thus, by increasing the pH of the tanning liquor beyond the usual level, the level of chromium tanning can be improved. However, the increased astringency of the chrome tanning agents leads to scarring i.e. lower quality leathers. In most cases, a loss of space also has to be accepted.
Desweiteren läßt sich durch Erhöhung der Temperatur der Gerbflotten von üblichen 38 bis 40 °C auf ca. 45 °C eine verbesserte Auszehrung der Chromgerbstoffe erreichen Die Temperaturerhöhung bringt jedoch ebenfalls einen Anstieg der Adstringenz der Chromgerbstoffe mit sich, so daß auch hier die Gefahr von Narbenzug und Rendementverlust, also der Qualitätsminderung des Leders gegeben ist.Furthermore, by increasing the temperature of the tanning liquors from the usual 38 to 40 ° C to approx. 45 ° C, an improved exhaustion of the chrome tanning agents can be achieved and loss of yield, i.e. the deterioration in the quality of the leather.
Aus der Literatur ist außerdem bekannt, daß aromatische Diund Tricarbonsäuren wie z.B. Phthalsäure und/oder deren Salze im Pickel oder in der Chromgerbung eingesetzt werden, um eine bessere Fixierung des Chroms in der Haut zu erreichen. Werden sie im Pickel angewandt, bedingt dies jedoch eine deutliche Verminderung der Penetrationsgeschwindigkeit der nachfolgenden Chromgerbstoffe, eine ungleichmäßige Chromverteilung und bei stärkeren, ungespaltenen Blößen sogar in manchen Fällen eine unzureichende Durchgerbung. Sollen sie in der Chromgerbung eingesetzt werden, muß zur Minderung dieser Mängel die Gerbung meist zweistufig geführt werden, indem mit meist organisch maskiertem Chrom(III)-Sulfat-Gerbstoff eine bei niedrigem pH-Wert verlaufende milde Vorgerbung vorgenommen wird, der dann der Zusatz der aromatischen Di- und Tricarbonsäuren allein oder in Gegenwart weiteren Chromgerbstoffs und/oder eines Basifizierungsmittels folgt.It is also known from the literature that aromatic di- and tricarboxylic acids such as phthalic acid and / or their salts are used in pimples or in chrome tanning, to achieve a better fixation of the chromium in the skin. If they are used in the pimple, however, this leads to a significant reduction in the penetration speed of the subsequent chrome tanning agents, an uneven chrome distribution and, in the case of stronger, unsplit nakedness, even insufficient tanning in some cases. If they are to be used in chrome tanning, tanning must usually be carried out in two stages in order to reduce these deficiencies by using mild organic tanning which is carried out with mostly organically masked chromium (III) sulfate tanning agent and which is then carried out with the addition of aromatic di- and tricarboxylic acids follow alone or in the presence of further chrome tanning agent and / or a base agent.
Weiterhin bekannt ist ein Chromspar-Gerbverfahren (US 4,715,861), bei dem 0,1 bis 2 Gew.-% einer Aldehyd- oder Ketocarbonsäure, vorzugsweise Glyoxylsäure, vor der Gerbung im Pickelbad als Ersatz oder teilweiser Ersatz für die üblicherweise verwendete Schwefelsäure oder Ameisensäure eingesetzt werden. Die Chrom-Gerbung wird im gleichen Bad durchgeführt. Dieses Verfahren ergibt sehr weiche Leder mit fest anliegendem Narben und verbesserten physikalischen Eigenschaften. Die Auszehrung der Chromgerbflotten wird zwar deutlich verbessert, ohne aber den erhöhten Ansprüchen in allen Fällen zu genügen.Also known is a chrome-saving tanning process (US Pat. No. 4,715,861), in which 0.1 to 2% by weight of an aldehyde or keto carboxylic acid, preferably glyoxylic acid, is used as a replacement or partial substitute for the sulfuric acid or formic acid usually used before tanning in the pimple bath will. The chrome tanning is carried out in the same bath. This process results in very soft leather with tightly fitting scars and improved physical properties. The consumption of the chrome tanning liquor is improved significantly, but without meeting the increased demands in all cases.
Bekannt ist ein anderes Verfahren (US 4,042,321), das die wie üblich gepickelten Blößen mit Chrom(III)salzen vorgerbt, und zur Ausgerbung eine Mischung von Chrom(III)salzen, säurebindenden Mitteln (Dolomit, MgO, Alkali- und Erdalkalicarbonate und/oder Bicarbonate) und aromatischen Di- und Tricarbonsäuren (Phthalsäure, Isophthalsäure, Bernsteinsäure usw.), deren Salzen oder Anhydriden verwendet. Bei diesem Verfahren wird eine sehr gute Auszehrung der Chromgerbflotten erzielt. Die erhaltenen Leder aber sind meist schlecht färbbar, haben einen groben Narben und ein schlechtes Rendement.Another method is known (US Pat. No. 4,042,321), which pretannens the picks that are pecked as usual with chromium (III) salts, and for tanning a mixture of chromium (III) salts, acid-binding agents (dolomite, MgO, alkali metal and alkaline earth metal carbonates and / or Bicarbonates) and aromatic di- and tricarboxylic acids (phthalic acid, isophthalic acid, succinic acid etc.), their salts or anhydrides. This procedure is a very good one Exhaustion of the chrome tanning fleets achieved. However, the leather obtained is usually difficult to dye, has a coarse grain and poor yield.
Gegenstand der Erfindung ist ein Verfahren zur Chromspargerbung, bei dem man die Bößen vor der Gerbung mit 0,5 bis 2 Gew.-%, vorzugsweise 0,7 bis 1,2 Gew.-%, einer Aldehyd- oder Ketocarbonsäure vorbehandelt, in üblicher Weise gerbt und anschließend mit 1 bis 4,5 Gew.-%, vorzugsweise 1 bis 3 Gew.-%, einer Mischung aus Chrom(III)salzen, säurebindenden Mitteln und aromatischen Di- oder Tricarbonsäuren oder deren Salzen ausgerbt.The invention relates to a process for chromium-saving tanning, in which the bosses are pretreated with 0.5 to 2% by weight, preferably 0.7 to 1.2% by weight, of an aldehyde or ketocarboxylic acid before the tanning Tanned and then tanned with 1 to 4.5% by weight, preferably 1 to 3% by weight, of a mixture of chromium (III) salts, acid-binding agents and aromatic di- or tricarboxylic acids or their salts.
Als Aldehyd- oder Ketosäure kommt vorzugsweise Glyoxylsäure, aber auch Brenztraubensäure in Frage. Die Vorbehandlung mit diesen Säuren erfolgt aus wäßriger Flotte mit den obengenannten Konzentrationen. Man kann diese Vorbehandlung separat durchführen, zweckmäßigerweise kombiniert man diese Vorbehandlung mit diesen Säuren mit dem Pickel. Die Kombination mit dem Pickel hat auch den Vorteil, daß durch den Zusatz der genannten Säuren zum Pickel die üblicherweise dort mitverwendeten maskierenden Säuren wie Ameisensäure oder Essigsäure entfallen können. Der Pickel enthält ansonsten die hierfür üblichen Säuren und Salze in den üblichen Konzentrationen, beispielsweise 0,1 bis 2 Gew.-% Schwefelsäure (90 %ig). Diese Vorbehandlung dauert im allgemeinen 0,5 bis 20 Stunden.The preferred aldehyde or keto acid is glyoxylic acid, but also pyruvic acid. The pretreatment with these acids is carried out from an aqueous liquor with the above-mentioned concentrations. This pretreatment can be carried out separately, it is expedient to combine this pretreatment with these acids with the pimple. The combination with the pimple also has the advantage that the addition of the acids mentioned to the pimple eliminates the masking acids which are usually used there, such as formic acid or acetic acid. The pimple otherwise contains the usual acids and salts in the usual concentrations, for example 0.1 to 2% by weight sulfuric acid (90%). This pretreatment generally lasts 0.5 to 20 hours.
Die anschließende Chromgerbung geschieht mit den üblichen im Handel befindlichen Chrom(III)-Gerbstoffen nach den an sich bekannten Verfahren.The subsequent chrome tanning is carried out using the customary commercially available chromium (III) tannins according to the processes known per se.
Das Chromangebot, bezogen auf das Blößengewicht, beträgt hierbei im allgemeinen 0,8 bis 1,5 Gew.-%. Die Gerbzeit beträgt ca. 30 bis 180 Minuten. Als Chrom(III)-Salze für die Gerbung eignen sich die üblichen für die Chromgerbung einsetzbaren Chrom(III)-Salze, insbesondere Chrom(III)-Sulfate, basische Chrom(III)-sulfate, ferner mit organischen Säuren, z.B. Ameisensäure, Essigsäure, maskierte Chrom(III)-Salze, selbstabstumpfende Chromgerbstoffe, die neben Chrom(III)-Salzen noch anorganische Salze, wie Natriumsulfat, enthalten, oder Umsetzungsprodukte von 6-wertigen Chromverbindungen mit Reduktionsmitteln.The chromium available, based on the pelt weight, is generally 0.8 to 1.5% by weight. The tanning time is approx. 30 to 180 minutes. As chromium (III) salts for The tanning is suitable for the chrome (III) salts which are customarily used for chrome tanning, in particular chromium (III) sulfates, basic chromium (III) sulfates, and also with organic acids, for example formic acid, acetic acid, and chromium (III) salts masked , self-dulling chromium tanning agents which, in addition to chromium (III) salts, also contain inorganic salts, such as sodium sulfate, or reaction products of hexavalent chromium compounds with reducing agents.
Im Anschluß an die eigentliche Gerbung erfolgt eine Ausgerbung durch Behandeln mit einer wäßrigen Lösung, die Chrom(III)-Salze, säurebindende Mittel und aromatische Di- oder Tricarbonsäuren oder deren Salze enthält.Following the actual tanning, the tanning is carried out by treatment with an aqueous solution which contains chromium (III) salts, acid-binding agents and aromatic di- or tricarboxylic acids or their salts.
Die zur Ausgerbung verwendeten Gemische enthalten als Chrom(III)-Salze bevorzugt Chromsulfate und basische Chromsulfate. Ferner sind auch maskierte Chrom(III)-Salze, insbeondere Chrom(III)-Sulfate, die zweckmäßig nur einen geringen Maskierungsgrad aufweisen, einsetzbar.The mixtures used for tanning preferably contain chromium sulfates and basic chromium sulfates as chromium (III) salts. Masked chromium (III) salts, in particular chromium (III) sulfates, which expediently only have a low degree of masking, can also be used.
Als säurebindende Mittel eignen sich z.B. Dolomit, Alkalicarbonate und -bicarbonate, Erdalkalicarbonate und -bicarbonate, Magnesiumoxid oder Natriumsulfit.Suitable acid-binding agents are e.g. Dolomite, alkali carbonates and bicarbonates, alkaline earth carbonates and bicarbonates, magnesium oxide or sodium sulfite.
Als Dolomit wird das mineralische Doppelsalz CaCO₃ · MgCO₃, das einen Gehalt von 20 bis 40 % CaO, vorzugsweise 25 bis 35 % CaO, und das einen Gehalt von 10 bis 25 ‰ MgO, vorzugsweise 16 bis 24 % MgO, aufweist, eingesetzt. Der Dolomit kann entweder für sich allein oder in Kombination mit anderen säurebindenden Stoffen eingesetzt werden, wobei der Gehalt der Gemische an Dolomit vorzugsweise mindestens 10 % der insgesamt verwendeten Menge an säurebindenden Mitteln betragen soll.The mineral double salt CaCO₃ · MgCO₃, which contains 20 to 40% CaO, preferably 25 to 35% CaO, and which has a content of 10 to 25 ‰ MgO, preferably 16 to 24% MgO, is used as dolomite. The dolomite can be used either alone or in combination with other acid-binding substances, the dolomite content of the mixtures preferably being at least 10% of the total amount of acid-binding agents used.
Besonders geeignet sind Gemische, die 10 bis 130 Gew.-% Dolomit pro 100 Gew.-% Cr₂O₃ enthalten. Die anzuwendende Dolomitmenge richtet sich nach der Basizität der eingesetzten Chrom(III)-Salze, ferner nach der Basizität, zu der diese Chrom(III)-Verbindungen im Verlauf der Gerbung geführt werden sollen, nach der Basizität und der Menge der in der Vorgerbung verwendeten Chrom(III)-Salze und nach der Menge der gegebenenfalls in der Mischung mitverwendeten weiteren säurebindenden Stoffe.Mixtures containing 10 to 130% by weight of dolomite per 100% by weight of Cr₂O₃ are particularly suitable. The amount of dolomite to be used depends on the basicity of the chromium (III) salts used, and also on the basicity to which these chromium (III) compounds are to be made in the course of the tanning, on the basicity and the amount of those used in the preliminary tanning Chromium (III) salts and according to the amount of other acid-binding substances which may be used in the mixture.
Aromatische Dicarbonsäuren und Tricarbonsäuren mit 8 bis 13 C-Atomen sind solche der Benzol- und Naphthalin-Reihe, die neben den Carboxyl-Gruppen noch Hydroxy-, Amino- oder Nitrogruppen und/oder Halogenatome enthalten können. Bevorzugt werden Phthalsäure und Isophthalsäure eingesetzt. Aromatische Di- und Tricarbonsäuren, die neben den Carboxyl-Gruppen noch Sulfonsäuregruppen enthalten, können nur bis zu etwa ein Drittel der insgesamt eingesetzten Carbonsäuremengen mitverwendet werden.Aromatic dicarboxylic acids and tricarboxylic acids with 8 to 13 carbon atoms are those of the benzene and naphthalene series which, in addition to the carboxyl groups, can also contain hydroxyl, amino or nitro groups and / or halogen atoms. Phthalic acid and isophthalic acid are preferably used. Aromatic di- and tricarboxylic acids, which contain sulfonic acid groups in addition to the carboxyl groups, can only be used up to about a third of the total amount of carboxylic acid used.
Die Carbonsäuren können sowohl in Form der freien Säuren, in Form von Gemischen der freien Säuren und den Salzen solcher Carbonsäuren, als auch allein in Form der Salze, zweckmäßig der Alkalimetallsalze angewendet werden. Bevorzugt werden pulverförmige Gemische der freien Carbonsäuren und deren Salze im Molverhältnis von 60:40 und 40:60 angewendet.The carboxylic acids can expediently be used both in the form of the free acids, in the form of mixtures of the free acids and the salts of such carboxylic acids and also solely in the form of the salts, the alkali metal salts. Powdery mixtures of the free carboxylic acids and their salts in a molar ratio of 60:40 and 40:60 are preferably used.
Die Ausgerbung erfolgt zweckmäßig im gleichen Bad durch Zugabe der Gemische in Pulverform. Die Komponenten der beanspruchten Gemische können bevorzugt gemeinsam zugegeben werden. Von diesen Komponenten können auch nur einige gemeinsam aber auch jede für sich zugegeben werden. Zweckmäßig werden die basischen Chrom(III)-Salze allein oder gemeinsam mit weiteren Komponenten zuerst zugegeben. Diese Chrom(III)-Salze können auch zusammen mit den zur Vorgerbung angewandten Chrom(III)-Salzen zugegeben werden.The tanning is expediently carried out in the same bath by adding the mixtures in powder form. The components of the claimed mixtures can preferably be added together. Only a few of these components can be added together, but also each individually. The basic chromium (III) salts are expediently added alone or together with further components. These chromium (III) salts can also be added together with the chromium (III) salts used for pretanning.
Die anzuwendenden Mengen der Gemische werden so bemessen, daß die insgesamt in der Vor- und Ausgerbung angebotene Cr₂O₃-Menge 1,2 bis 2 %, insbesondere 1,5 bis 1,8 % Cr₂O₃, bezogen auf Blößengewicht, beträgt und daß die aromatischen Di- und/oder Tricarbonsäuren mit 8-14 C-Atomen und/oder deren Salze wenigstens 1,0 Mol pro Mol Chromoxid der insgesamt sowohl für die Vorgerbung als auch für die Ausgerbung eingesetzten Chromgerbstoffe betragen.The amounts of the mixtures to be used are such that the total amount of Cr₂O₃ offered in the pretanning and retanning is 1.2 to 2%, in particular 1.5 to 1.8% Cr₂O₃, based on the weight of the skin, and that the aromatic di - And / or tricarboxylic acids with 8-14 carbon atoms and / or their salts amount to at least 1.0 mole per mole of chromium oxide of the total chrome tanning agents used both for pretanning and for tanning.
Die Ausgerbung wird mit einer Flotte im Flottenverhältnis von unter 100 %, vorzugsweise 10 bis 50 %, bezogen auf Blößengewicht, bei Temperaturen von ca. 36-45 °C vorgenommen. Die Gerbung wird so geführt, daß die Flotte am Ende der Gerbung einen pH-wert von über 3,6, insbesondere von 3,9 bis 4,5 aufweist. Die Ausgerbung dauert ungefähr 7 bis 12 Stunden.The tanning is carried out with a liquor in a liquor ratio of less than 100%, preferably 10 to 50%, based on the pelt weight, at temperatures of approx. 36-45 ° C. The tanning is carried out in such a way that at the end of the tanning the liquor has a pH of more than 3.6, in particular 3.9 to 4.5. The tanning process takes approximately 7 to 12 hours.
Die oben beschriebene Arbeitsweise empfiehlt sich besonders für dünnere Blößen. Bei dickeren Blößen ist es vorteilhaft, einen Teil der Mischung aus Chrom(III)-Salzen, säurebindenden Mitteln und aromatischen Di- oder Tricarbonsäuren vor der Vorgerbung dem Pickelbad zuzusetzen. Hierfür werden ca. 0,5 bis 2,5 Gew.-%, vorzugsweise 0,5 bis 1,5 Gew.-% bezogen auf Blöße genommen. Der Rest dieser Mischung, ca. 1,5 bis 2 Gew.-%, wird dann zur Ausgerbung verwendet wie oben beschrieben. Alle beschriebenen Arbeitsgänge lassen sich im selben Bad durchführen, man kann aber auch in mehreren getrennten Schritten arbeiten.The method of operation described above is particularly recommended for thinner nakedness. In the case of thicker pelts, it is advantageous to add part of the mixture of chromium (III) salts, acid-binding agents and aromatic di- or tricarboxylic acids to the pimple bath before the pretanning. For this, about 0.5 to 2.5% by weight, preferably 0.5 to 1.5% by weight, based on the nakedness, is used. The rest of this mixture, about 1.5 to 2 wt .-%, is then used for tanning as described above. All of the operations described can be carried out in the same bathroom, but you can also work in several separate steps.
Das nach diesem Verfahren erhaltene Leder ist kochgar, weich, festnarbig, extrem feinnarbig, gut färbbar mit hervorragenden physikalischen Eigenschaften und gutem Rendement. Der Gehalt an Chromoxid in der Gerbrestflotte ist extrem niedrig.
Claims (5)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE3814220A DE3814220A1 (en) | 1988-04-27 | 1988-04-27 | METHOD FOR CHROME SAVING |
DE3814220 | 1988-04-27 |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0339437A1 true EP0339437A1 (en) | 1989-11-02 |
Family
ID=6353008
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP89106934A Withdrawn EP0339437A1 (en) | 1988-04-27 | 1989-04-18 | Tanning process saving chromium |
Country Status (9)
Country | Link |
---|---|
US (1) | US4978361A (en) |
EP (1) | EP0339437A1 (en) |
JP (1) | JPH01315500A (en) |
KR (1) | KR900016474A (en) |
AR (2) | AR240483A1 (en) |
AU (1) | AU614055B2 (en) |
BR (1) | BR8901956A (en) |
DE (1) | DE3814220A1 (en) |
PT (1) | PT90355A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2686099A1 (en) * | 1992-01-14 | 1993-07-16 | Hoechst France | APPLICATION OF SILICA SOILS TO OBTAIN WHITE STABILIZED PICKLE WHITE OR STABILIZED WHITE SKIN. |
EP0634517A1 (en) * | 1993-07-10 | 1995-01-18 | Hoechst Aktiengesellschaft | Process for dying for pelts with oxidation dyes |
EP0822263A1 (en) * | 1996-07-31 | 1998-02-04 | Seta S.A.-Extrativa Tanino de Acacia | Leather tanning process |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0583697A2 (en) * | 1992-08-14 | 1994-02-23 | Hoechst Aktiengesellschaft | Tanning process saving chrome and improved fixing of chrome |
TR200708916A1 (en) * | 2007-12-25 | 2009-07-21 | Soda Sanay� A.�. | The use of chromium complexes in leather. |
EP2853605A1 (en) | 2013-09-30 | 2015-04-01 | Rhodia Poliamida E Especialidades Ltda | Tanning process for obtaining leather |
EP2853604A1 (en) | 2013-09-30 | 2015-04-01 | Rhodia Poliamida E Especialidades Ltda | Tanning process |
CN105567885B (en) * | 2016-01-26 | 2017-11-21 | 湖州长城皮业有限公司 | One kind is without two layers of shoe lining leather preparation technology of chrome tanning pigskin |
CN105543425B (en) * | 2016-01-26 | 2017-11-17 | 湖州长城皮业有限公司 | One kind is without chrome tanning goat leather for making garment preparation technology |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2271290A1 (en) * | 1974-05-18 | 1975-12-12 | Bayer Ag | |
EP0201054A1 (en) * | 1985-05-10 | 1986-11-12 | Hoechst Aktiengesellschaft | Tanning process saving chrome |
-
1988
- 1988-04-27 DE DE3814220A patent/DE3814220A1/en not_active Withdrawn
-
1989
- 1989-04-13 AR AR313664A patent/AR240483A1/en active
- 1989-04-18 EP EP89106934A patent/EP0339437A1/en not_active Withdrawn
- 1989-04-24 PT PT90355A patent/PT90355A/en not_active Application Discontinuation
- 1989-04-25 AR AR313762A patent/AR240482A1/en active
- 1989-04-25 US US07/343,010 patent/US4978361A/en not_active Expired - Fee Related
- 1989-04-25 KR KR1019890005413A patent/KR900016474A/en not_active Application Discontinuation
- 1989-04-26 AU AU33350/89A patent/AU614055B2/en not_active Ceased
- 1989-04-26 JP JP1104780A patent/JPH01315500A/en active Pending
- 1989-04-26 BR BR898901956A patent/BR8901956A/en not_active Application Discontinuation
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2271290A1 (en) * | 1974-05-18 | 1975-12-12 | Bayer Ag | |
EP0201054A1 (en) * | 1985-05-10 | 1986-11-12 | Hoechst Aktiengesellschaft | Tanning process saving chrome |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2686099A1 (en) * | 1992-01-14 | 1993-07-16 | Hoechst France | APPLICATION OF SILICA SOILS TO OBTAIN WHITE STABILIZED PICKLE WHITE OR STABILIZED WHITE SKIN. |
EP0551785A1 (en) * | 1992-01-14 | 1993-07-21 | SOCIETE FRANCAISE HOECHST Société anonyme dite: | Application of silica sols for obtaining a skin called "blanc picklé stabilisé" or "blanc stabilisé" |
US5480456A (en) * | 1992-01-14 | 1996-01-02 | Societe Francaise Hoechst | Silica sols for obtaining a hide which is called a stabilized pickled or white or stabilized white |
EP0634517A1 (en) * | 1993-07-10 | 1995-01-18 | Hoechst Aktiengesellschaft | Process for dying for pelts with oxidation dyes |
US5466263A (en) * | 1993-07-10 | 1995-11-14 | Hoechst Aktiengesellschaft | Process for dyeing fur skins with oxidation dyes |
EP0822263A1 (en) * | 1996-07-31 | 1998-02-04 | Seta S.A.-Extrativa Tanino de Acacia | Leather tanning process |
Also Published As
Publication number | Publication date |
---|---|
JPH01315500A (en) | 1989-12-20 |
AU614055B2 (en) | 1991-08-15 |
DE3814220A1 (en) | 1989-11-09 |
KR900016474A (en) | 1990-11-13 |
PT90355A (en) | 1989-11-10 |
BR8901956A (en) | 1989-12-05 |
AU3335089A (en) | 1989-11-02 |
US4978361A (en) | 1990-12-18 |
AR240482A1 (en) | 1990-04-30 |
AR240483A1 (en) | 1990-04-30 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
DE2626430C2 (en) | Process for tanning leather and tanning mix | |
CH615224A5 (en) | ||
EP0339437A1 (en) | Tanning process saving chromium | |
EP0201054B1 (en) | Tanning process saving chrome | |
EP0429830A2 (en) | Method of tanning hides and retanning chrome-tanned leather | |
EP0533011B1 (en) | Process for producing chrome-tanned leather | |
EP0304677A1 (en) | Tanning method with high chrome exhaustion | |
EP0554216B1 (en) | Process for pickling and pretanning of hides | |
DE2424300C3 (en) | Process for chrome tanning and tanning mix therefor | |
EP0349892A2 (en) | Tanning method presenting a high chrome exhaustion of the tanning bath | |
CH691062A5 (en) | An aqueous composition for pre-tanning of hide pelts or retanning leather. | |
DE2424301C3 (en) | Process for chrome tanning and tanning mix therefor | |
EP0270767A1 (en) | Tanning process saving chrome | |
EP0554217B1 (en) | Aqueous composition for pretanning hides | |
DE2739844A1 (en) | CHROME TANING PROCESS | |
DE1303521C2 (en) | TANNING PROCESS USING BASIC ALUMINUM-CHROME (III) COMPLEX COMPLEXES | |
DE487670C (en) | Process for tanning hides and skins with the help of iron compounds | |
DE2755087A1 (en) | Tanning of leather and pelts - in presence of chromium salt pref. using carboxyl-contg. polymer and/or polycondensate tanning agent | |
EP0204213B1 (en) | Method of retanning chrome-tanned leather | |
DE3306374A1 (en) | METHOD FOR TANNING SKIN WITH A HIGH BASIC CHROME TANNER | |
DE587724C (en) | Process for the production of chrome tanning agents | |
DE642728C (en) | Process for tanning hides and skins using iron compounds | |
DE3636002A1 (en) | Improved process for the chrome-tanning of pelts | |
DE750988C (en) | Process for tanning with tanning agents containing aluminum | |
DD254595A1 (en) | METHOD OF MAKING SOFT, WHITE LEATHER |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
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 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): DE ES FR GB IT NL |
|
17P | Request for examination filed |
Effective date: 19900426 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN |
|
18W | Application withdrawn |
Withdrawal date: 19930421 |