KR20060127416A - A process for making leather - Google Patents

Abstract

The present invention relates to a leather process whereby the post tanning wet operations are done prior to tanning stage itself to make leather in ecofriendly manner in substantially shorter duration. It is envisaged to have enormous potential application in leather industry for making leathers with comparable sofness and grain smoothness, whereby the pollution load would be significantly less compared to that of the conventional leather processing.

Description

A process for making leather

TECHNICAL FIELD The present invention relates to a leather manufacturing process, and more particularly, to a leather manufacturing process for producing leather in an environmentally friendly manner in a substantially shorter period by performing a post tanning wet process before the tanning process. This is a leather manufacturing process that results in significantly reduced amounts of contaminants compared to conventional leather manufacturing processes and has a comparable softness and smooth grain, which will be widely used in the leather industry.

The conventional leather manufacturing process involves four important processes. That is, pre-tanning, tanning, post tanning, and finishing processes. Processes in which one or more steps are combined are various biological and organic as described by Germann (Science and Technology for Leather into the Next Millennium, Tata McGraw-Hill Publishing Company Ltd., New Delhi, p. 283, 1999). This includes supplying as well as removing inorganic materials. Conventional leather treatment methods include soaking, lime, reliming, deliming, bating, pickling, chrome tanning and basification. ), Steps 14-15 including rechromimg, basification, neutralization, retanning, dyeing, fatliquoring and fixing . The lime and relime processes supply lime and sodium sulfide to clean the leather matrix by removing hair, skin and other unwanted materials to produce pellets. The deliming process supplies quaternary ammonium salts to neutralize the alkali. The batting process uses pancreatic enzymes to clean the leather mattress. The pickling process prepares the leather for the subsequent tanning process. The tanned leather matrix is retanned to obtain better quality, to be fatliquored, to have the required softness, and to be dyed to obtain the required shade. This conventional technique generates a large amount of contaminants. According to the analysis of Aloy et al (Tannery and Pollution, Center Technique Du Cuir, Lyon, France, 1976), about 98% of total pollution occurs in tanning. This includes Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Dissolved Solids (TDS), sulfides, chlorides, sulfates, chromium, and the like. This is fundamentally due to the fact that conventional leather manufacturing processes use a 'do-undo' process as described by Bienkewicz (Physical Chemistry of Leather Making, Krieger Publishing, Malabar, FL, 1983). Is caused. 'do-undo' processes include swell-deswell (lime-lime); Pickle-depickle (pickling-base), recromming-baseling (acidification-baseling) and neutralization-fixing (baseling-acidification) and the like. That is, conventional leather treatment methods give a wide pH change to the skin / leather. Such pH changes require the use of acids and alkalis, resulting in salts. As a result, as reported by Thanikaivelan et al (Journal of Society of Leather Technologists and Chemists, 84, 276, 2000), the total amount of COD, TDS, chlorides, sulphates and other minerals increased in water used in tanning. do.

Conventional chromium tanning generally involves pickling and tanning using basic chromium sulfate (BCS) by a basicization process. As reported by Aloy et al (Tannery and Pollution, Center Technique Du Cuir, Lyon, France, 1976), since pickling involves the use of 8-10% sodium chloride salt with sulfuric acid, the pickling solution used is a solid. Many of the components are dissolved and have a significant amount of COD. As reported by Herfeld and Schubert (Das Leder, 26, 117, 1975), acids that do not swell in pickling are used to reduce the total dissolved solids. There are some better ways to treat chromium. This is known by the well-ventilated chromium tanning method reported by Chandrasekaran (Leather Science, 34, 91, 1987), Venba et al (Poster presented at 30 ^th Leather Research and Industry Get-together, Chennai, 1995). Pickle-less tanning method, chrome recovery and reuse reported by Covington et al (journal of the Society of Leather Technologists and Chemists, 67, 5, 1983), and Rao et al (Science and technology for leather) into the next millennium, Proceedings of the XV International Union for Leather Technologists and Chemists Societies congress, p. 295, 1999). The conventional post tanning process involves 7-8 main steps. 7-8 major steps include rechroming, basicization, neutralization, washing, retanning, staining, branches, and fixation. The post tanning process causes TDS, COD and heavy metal contamination, as analyzed by Simoncini and Sammarco (Proceedings of the III International Union for Leather Technologists and Chemists Societies congress, Germany, 1995). Common post tanning chemicals cause the COD to become large, which is achieved by using optimized amounts of high performance auxiliaries, which reduce the release of bio-treatable residues. Can be mitigated. Retanning and branching choices are based on their biodegradability and inhalation properties. However, improving these is specified as a task. The implementation of all advanced technical and environmentally friendly chemicals involves not only financial investments but also mechanical requirements. This requires the development of integrated leather manufacturing process technology and improving the process order. Very few attempts have been made to improve the overall leather manufacturing process. Thanikaivelan et al (Journal of the Society of Leather Technologists and Chemists 84, 276, 2000; 85, 106, 2001) attempted to make leather in a narrow range of pH 4.0-8.0. Thanikaivelan et al (Journal of the American Leather Chemists Association 98, 173, 2003) invented a three-step tanning process based on biochemistry at pH 4.0-8.0. The three-step tanning process involves hair removal at pH 8.0 without using lime, opening the fibers with sodium hydroxide, and chrome tanning at pH 8.0 without pickling. Saravanabhavan et al (Green Chemistry 5, 2003, 707) have successfully invented a three-step tanning method, which involves hair removal without the use of lime and sodium sulfide, fiber opening with enzymes, and chrome tanning at pH 8.0. It involves doing it. However, no attempt was made to change the stage of the leather manufacturing process. The above mentioned step of reference is, first of all, up to prime tanning. This three step process is followed by a conventional post tanning process involving 7-8 main steps including recroming, basicization, neutralization, washing, retanning, dyeing, eggplant, and fixation. The present invention provides a better leather manufacturing process than the conventional method shown in the flow chart of FIG.

The main technical problem to be achieved by the present invention is to provide a new order of leather manufacturing process.

Another technical problem to be achieved by the present invention is to provide a new order of leather manufacturing process, including a tanning process that does not require pickling and basicization steps.

Another technical task of the present invention is to provide a new order of leather manufacturing process, including post tanning processes that do not require acid cleaning, recroaming, neutralization, cleaning and fixing.

Another technical task of the present invention is to provide a new order of leather manufacturing process that can significantly reduce chemical oxygen demand, total solids and other contamination.

Another technical problem to be solved by the present invention is to provide a new step of treating raw skin which is not tanned with syntans, eggplant, and dyes, which are typically used as chemicals in the post tanning wet process, thereby making the process of manufacturing leather environmentally friendly. to provide.

The main object of the present invention is to provide a new order of leather manufacturing process that overcomes the above mentioned problems. The present invention provides a tanning process that does not require pickling and basicization steps. Moreover, the post tanning process does not require acid cleaning, recromming, neutralization, cleaning and fixing. The leather thus produced is comparable in quality to the leather produced in the usual leather manufacturing process steps. This new sequence of processes can significantly reduce chemical oxygen demand, total solids and other contamination. The leather manufacturing process of the present invention has fewer steps than the conventional process by changing the process sequence, and provides a simpler process. Another advantage of the present invention is that contaminants, some specific chemicals, water usage, power and time are reduced.

It is a feature of the present invention to treat untanned hides with syntans, eggplants, and dyes typically used as a post tanning wet treatment process chemical. Thereby, it is possible to provide an environmentally friendly leather manufacturing process. Syntans is a synthetic tanning agent based almost on organic chemicals and is used to fill leather. Luganyl FBO, Sandel Pearl Brown BSI, Dermapel blue IDBN and Sellafast orange-CGL are the dyes used in this study. The leather manufacturing process according to the present invention has fewer steps than the conventional process by changing the process sequence, and the process becomes simpler. This simple process eliminates several process steps, thus reducing the amount of chemical used. However, the nature and concentration of the chemicals used in the process of the present invention are the same as those of conventional processes. The main advantage of the present invention is the reduction of contaminants, specific chemicals, water usage, power and time (Tables 1 and 2; FIG. 1).

Leather manufacturing process of the new order according to the main embodiment of the present invention,

(a) Delimed and / or batted pellets are treated with 2-6% fatliquor at a temperature of about 20-55 ° C. and pH 5.0-8.5, optionally 1-6% adding synthetic tanning agent (syntan) and dye of w / w,

(b) mix the result of step (a) for about 3 hours to obtain fatliquoring raw material,

(c) 4-25% w / w of tanning agent pH 5.0-8.5 is mixed with the branched raw material of step (b), optionally adding a complexing agent, and the conventional method for about 3 hours. adjusting the pH of the material obtained in step (c) to 3.5-4.5 to obtain process treated wet leather.

In the new order of leather manufacturing process according to another embodiment of the present invention, the briquette of step (a) is acrylic, phenol condensates, urea condensates, sulfones, melamine, Any one selected from the group of protein condensates or combinations thereof.

In a new order leather manufacturing process according to another embodiment of the present invention, the dye of step (a) is any one selected from an acid, a metal complex, or a combination thereof.

In the new order of leather manufacturing process according to another embodiment of the present invention, the branching agent of step (a) is any one selected from the group comprising vegetable, synthetic, semisynthetic branching agents, or a combination thereof.

In a new order of leather manufacturing process according to another embodiment of the present invention, the tanning agent of step (c) is selected from the group comprising base chromic sulfuric acid, vegetable tannin, aluminum syntan or chromium-silica.

In a new order of leather manufacturing process according to another embodiment of the present invention, the complexing agent of step (c) is selected from the group comprising polymer syntan or acrylic syntan.

In step (a) of a new order of leather manufacturing process according to another embodiment of the present invention, the percentage of branching added is based on the weight of the fresh raw hide.

In step (c) of a new order of leather manufacturing process according to another embodiment of the present invention, the percentage of tanning agent is based on the weight of the fresh skin obtained in step (a).

The dye of step (a) of the new order of leather manufacturing process according to another embodiment of the present invention is about 2%.

The dye of step (a) of the new order of leather manufacturing process according to another embodiment of the present invention is about 1%.

The complexing agent of step (c) of the new order of leather manufacturing process according to another embodiment of the invention is about 2%, preferably about 1%.

Another embodiment of the present invention is directed to a new order of leather manufacturing process that takes about 6-10 hours for the leather to be processed.

Yet another embodiment of the present invention is directed to a new order of leather manufacturing process in which softness, fullness and texture density are improved over conventional processes of 8.5 ± 2.

Yet another embodiment of the present invention is directed to a new order of leather manufacturing process with improved softness, richness, and grain density than conventional processes of 8.2 ± 2.

Other specific details of the invention are included in the detailed description and drawings.

The present invention is described in more detail in the embodiments disclosed below, but the following embodiments are provided for illustration, which does not limit the scope of the invention.

1 is a flowchart illustrating a conventional leather manufacturing process and a new order of leather manufacturing process according to an embodiment of the present invention.

Example 1 (disclosed in US Patent Application No. 10 / 618,997)

A 2 liter round flask equipped with a stirrer contains 534gms of anthracene and 326ml of concentrated sulfuric acid. The flask is heated to a temperature of 140 ° C. for 90 minutes while continuing to stir the contents in the flask. 1 ml of this is placed in a beaker and shaken to add 3 ml of water. By observing the formation of a clear solution without the naphthalene odor, it can be confirmed that it is completely sulfonated. The sulfonated material is transferred to a reactor equipped with a thermometer, stirrer and drop funnel. Stir the mass continuously for 10 minutes while maintaining a temperature of 80 ° C. The sulfonated material was added to a mixture of 5.4 gms of oxalic acid, 4.14 gms of salicylic acid, and 10 gm of phthalic acid dissolved in 50 ml of water, and then stirred at 80 ° C. 1.5 gms of polymethacrylic acid is added to the sulfonic acid mixture and the mixture is heated to 80 ° C. for 1 hour. Add a portion of the reaction mixture to the beaker and add 2 ml of water. The pH of the solution in the beaker is adjusted to 3 and a clear solution is obtained which indicates that the reaction is complete. About 540 ml of water is added to the solution and the reaction solution is cooled to room temperature before it is transferred to a bucket. A solution containing 220 gm of sodium hydroxide was added to 500 ml of water, and an aqueous solution of 200 gm of sodium carbonate was added to 400 ml of water to increase the pH of the solution to 3. The slurry is aerated for 45 minutes in the usual manner and filtered using a cloth with a pore size of 5-10 μ. The filtrate is sprayed and dried at 260 ° C. and the white powder is stored in a plastic container. To the limed sheepskin is added 1.0% of prepared briquettes with 5% BCS on 20% float. Drum for 1 hour and add 80% water. The drum is then continued for 1 hour, and penetration can be assessed depending on whether a uniform blue color is checked along the cross section. The pH of the solution and the cross section can be 4.4. Drain the tank and hang out wet blue leather. The next day, the post tanning of the leather is carried out by the usual method of manufacturing the outer skin. The amount of chromium reduced in the tanning liquid used is 95%. The richness of crust leather is much better than conventional chrome tanned leather.

Example 2

Five batted goatskin skins, weighing 4.6 kgs of fresh skin weight, are placed in a small laboratory tanning drum. The cross-sectional pH of the baited skin is 8.0. Baited hides are washed with 9200 ml of water for 10 minutes and drained.

23 gms of Basintan DI (phenol condensed product from BASF (Badishe Anilin- & Soda-Fabrik AG)), 23 gms of Vernatan OS (phenol condensates from Color Chemicals), 46 gms of Relugan RE (co-based material from BASF) are added to the drum simultaneously with 6900 ml of water. Drum for 1 hour. Subsequently, 4.6 gms of Ruganil FBO (acid dye from BASF) is added. Drum for 30 minutes. Subsequently, a mixture emulsion of fatliquors in 460 ml of hot water at 50 ° C., namely, 46 gms of Bernol liquor PN (natural oil based material from Color Chemicals), 46 gm of Bernol liqueur ASN (Vernol liquor ASN) ) (Synthetic fatliquor from Color Chemicals) and 46 gms of Balmol SX-20 (synthetic fatliquor from Balmer Lowry) are added. Drum for 1.5 hours. A mixture of 46 gm of Shintan and 230 gm of BCS (Golden Chemicals, Mumbai, India) is added to the polymer invented by Kanthimathi et al (Example 1 above disclosed in US patent application No. 10 / 618,997). The pH of the leather cross section is 4.5. Wash the leather with 9200 ml of water for 10 minutes. The leather which has undergone the wet treatment described above is taken out of the drum and laid down.

Example 3 (disclosed in Indian Patent Application No. Del / 770/2000)

In a flask equipped with a stirrer, mix 303 gm of sodium dichromate and 105 gm of sodium metasilicate (Na2SiO3.5H2O). Continue stirring and add 550 ml of water to the material. 188 ml of 98% sulfuric acid is slowly added to the reaction mixture. A mixture of 41 ml of molasses and 41 gm of molasses in 41 ml of water in a beaker is added to the material, which is added by dropping the mixture into a drop funnel for at least 20 minutes. The temperature of the mixture is 95 ° C. The reaction mixture is mixed with a mixture of 40 gm of phthalic acid and 55 gm of sodium tartrate for at least 10 minutes.

Add 50 gm of molasses to 50 ml of water in the beaker and mix the material for at least about 30 minutes. Add the material to a mixture of 43 gm of phthalic acid and 60 gm of sodium tartrate and mix for at least 10 minutes. The temperature of the reaction mixture is 105 ° C. Stir again for 2 hours after the organic ligand is added completely. A 10% solution of this material is subjected to a diphenyl carbazide test to see if no chromium (VI) is detected. The reaction mixture thus formed is aged for 12 hours. Checking the pH of the 1: 1 aqueous solution of the mixture yields 2.7. The mixture is filtered through a cloth, which is dried by spraying at 260 ° C. for 3 seconds of contact time. This powder is stored in a plastic container. This product provides 1.0% metal oxide of the raw material weight and is used to tan pickled goat skin. The resulting leather has a shrinkage temperature of 109 ° C., with 91 and 90% of silica and chromium consumed, respectively. A general process is then used to post tan the skin of the tanned leather. The resulting leather has stronger features compared to conventional chrome tanned leather and is softer, more pliable, stronger and smoother.

Example 4

In a small experimental tanning drum, four battered cowhide leather weighing 25.6 kg fresh raw hides are placed. The cross-sectional pH of the baited skin is 8.0. Baked raw hides are washed with 51200 ml of water for 10 minutes and then dried.

512gms of Basintan DI (phenol condensate from BASF), 256gms of Vernatan OS (phenol condensate from Color Chemicals), 256gms of Basintan FB6 (urea melamine based material from BASF) and 256gms of Vernatan RD35 (from Color Chemistry) A syntans mixture of acrylic copolymer based material) is added to the drum simultaneously with 12800 ml of water. Drum for about 1 hour. Subsequently, 256 gms of Sandelfel Brown BSI (acid dye of Clariant) is added. Drum for 30 minutes. Subsequently, the eggplant mixture was mixed with 2560 ml of 25 ° C hot water, 256 gms of Bernol liqueur PN (natural oil based material from Color Chemicals), 256 gms of Bernol liqueur ASN (synthetic eggplants from Color Chemicals) and 256 gm of Balmol SX-20 ( A mixture of Balmer Lowry's synthetic eggplant) is added to the drum. Drum for 1 hour. 1280 ml of 10% concentration of formic acid is added in two portions at 10 minute intervals. Drum for 1 hour. The pH of the cross section is 6.0. This is accomplished by adding 1792 gm of chromium-silica tanning agent as invented by Thanikaivelan et al (Example 3 disclosed in Indian Patent Application No. Del / 770/2000). Drum for 8 hours. At the end of tanning the pH is 4.0. The leather is washed with 51200 ml of water for 10 minutes. The wet treated leather is removed from the drum and laid down.

Example 5

Five battered sheepskin skins with a weight of fresh skin of 5.6 kg are generally degreaseed from small laboratory tanning drums. The grease-free skin has a cross-sectional pH of 8.0.

Grease-free hides are washed with 11200 ml of water for 10 minutes and dried. Raw hides are placed in a drum with 5600 ml of water. The pH of the raw skin is 6.0 by adding 190 ml of 10% concentration of formic acid two times at 10 minute intervals. Continue drumming for 30 minutes. 112 gms of Basintan FB6 (urea melamine based material from BASF) is added to the drum. Drum for 1 hour. Then, 34 gms of luganyl FBO (acid dye from BASF) is added. Drum for 30 minutes. Subsequently, a mixture emulsion of eggplants, that is, 56 gms of Bernol liqueur SS (semi synthetic eggplants from Color Chemicals), 56 gms of Bernol liqueur ASN (synthetic eggplants of Color Chemicals), 56 gms of Balmol SXE (Balmer) Lowry synthetic eggplant), 56 gms of balmool LB-20 (balmer lowry synthetic eggplant) and 56 gm of Lipoderm liquor SLW (BASF's synthetic eggplant) with 560ml of 40 ℃ hot water Add to the drum. Drum for 1.5 hours. This is due to adding 280 gms of BCS (percent based on flashed weight). Drum for 3 hours. The pH of the cross section is 3.8. The leather is washed with 11200 ml of water for 10 minutes. The wet leather is removed from the drum and laid down.

Example 6

Four bait buffcalf hides weighing 26 kg of fresh hide weight are placed in a small laboratory tanning drum. Baked raw skin has a pH of 8.5. Baked raw hides are washed with 52000 ml of water for 10 minutes and dried. 260 gms of Basintan P (phenol condensate from BASF), 260 gms of Vernatan OS (phenol condensate from Color Chemicals), 260 gms of Basintan FB6 (urea melamine based material from BASF) and 260 gm of lelugan RE (copolymer of BASF Corporation) The syntans mixture of system material) is added to the drum simultaneously with 13000 ml of water. Drum for about 1 hour. Subsequently, a mixture of 130 gms of ruganyl FBO (acid dye from BASF) and 130 gms of Dermapearl Blue IDBN (direct dye from Client's mordant) is added. Drum for 30 minutes. Subsequently, a mixture of eggplants was added to 2600 ml of hot water at 50 ° C, 260 gms of Bernol liqueur PN (eggplants using natural oils from Color Chemicals), 260 gms of Bernol liqueur ASN (synthetic eggplants of Color Chemicals) and 260 gms of Balmol SX- 20 (Bulmer Lowry's synthetic eggplant) is added to the drum. Drum for 1 hour. Add 5.2 kg of Wattle to the drum. Drum for 8 hours. Then, 780 ml of formic acid (10% diluted) was added twice at 10 minute intervals, followed by drumming for 1 hour. The pH of the cross section is 3.5. The leather is washed with 52000 ml of water for 10 minutes. Processed wet leather is removed from the drum and laid down.

Example 7

Five baited chlorine hides weighing 4.6 kg of fresh hide weight are placed in a small laboratory tanning drum. The cross-sectional pH of the baited skin is 8.0. Baked hides are washed for 10 minutes with 9200 ml of water and dried.

46 gms of Sellasol PR (protein condensate from Together For Leather (TFL)), 23 gms of Bernatan OS (phenol condensate from Color Chemicals), 46 gms of Basintan FB6 (urea melamine based from BASF) and A syntans mixture of 46 gms of lelugan RE (copolymer of BASF) is added to the drum simultaneously with 2300 ml of water. Drum for 1 hour. Subsequently, 28 gms of dermafel blue IDBN (a dye without a mordant of Clariant) is added. Drum for 30 minutes. Subsequently, 138 gms of Bernol Liqueur ASN (synthetic eggplant made by Color Chemical Co.) is added to the drum with 460 ml of hot water at 50 ° C. Run for 1.5 hours. Add 690 gm of bottle to the drum. Drum for 2 hours. 140 ml formic acid (10% diluted) was added twice at 10 minute intervals and the drum treatment continued for 1 hour. The pH of the cross section is 3.5. The leather is washed with 9200 ml of water for 10 minutes. The wet leather is removed from the drum and laid down.

Example 8

Four bait beef hides weighing 25.6 kg of fresh hide weight are placed in a small laboratory tanning drum. The cross-sectional pH of the baited skin is 8.0. Baked raw hides are washed with 51200 ml of water for 10 minutes and dried.

512gms of Basintan DI (phenol condensate from BASF), 256 gms of Bernatan OS (phenol condensate from Color Chemicals), 256gms of Basintan FB6 (urea melamine based material from BASF) and 256gms of Lelugan RE (from BASF Corporation) A syntans mixture of copolymerizable material) is added simultaneously with 12800 ml of water to the drum. Drum for about 1 hour. Subsequently, 256 gms of ruganyl FBO (acid dye from BASF) is added. Drum for 30 minutes. Subsequently, 256 gms of Bernol liqueur PN (branching agent using natural oils from Color Chemicals), 256 gms of Bernol liqueur ASN (synthetic eggplants of Color Chemicals) and 256 gms of Valmol SX-20 (Balmer Row) in 2560 ml of hot water at 50 ° C. Add Lisa's synthetic eggplant) to the drum. Drum for 1 hour. 1280 ml of 10% strength formic acid is added twice at 10 minute intervals and the drum treatment is continued for 1 hour. The pH of the cross section is 5.0. This is due to the addition of 1536 gm of BCS (based on raw material weight) and Relugan RF (material using acrylic from BASF). Drum for 8 hours. After tanning, the pH is 4.0. The leather is washed with 51200 ml of water for 10 minutes. The treated leather is removed from the drum and laid down.

Example 9 (disclosed in Indian Patent Application No. Del 88/2002)

25gms of naphthalene and 25ml of concentrated sulfuric acid are placed in a 250ml round flask with a stirrer. Heat to 80 ° C. for 120 minutes while constantly stirring the contents of the flask. Shake a small amount of the above contents in a beaker and 1 ml of water. If a clear solution without a naphthalene odor was obtained, the sulfonation reaction was carried out completely. At the same time, add 0.5 gm of salicylic acid to another beaker and stir at 25 ° C., add 0.5 ml of concentrated sulfuric acid. The slurry is left to stir for 3 hours with occasional stirring. The naphthalene sulfuric acid prepared in the flask is cooled to 60 ° C. and transferred to a reactor equipped with a thermometer, agitator, and drop funnel. The material is continuously stirred for 10 minutes while maintaining a temperature of 60 ° C. using a thermostat. A mixture of 0.2 gm of polyacrylic acid, 0.25 gm of phthalic acid, 1 gm of citric acid, and 0.14 gm of salicylic acid is dissolved in 10 ml of water in a beaker. This is added to the reaction mass of the reactor via a drop funnel. The mixture is heated at 65 ° C. for 20 minutes. 250 gms of aluminum sulfate is added to the material with agitation with 100 ml of water. The temperature of the bath is gradually increased to 70 ° C. and heating is continued for 60 minutes. Sulfo salicylic acid prepared in the beaker is added to the material and heating is continued for another 30 minutes. Transfer the mixture to a bucket and continue stirring to dissolve 60gms of sodium sulfate in 100ml of water, bringing the pH to 2.5. Pass air through the solution for 70 minutes. The slurry is filtered using a muslin cloth with a pore size of 5-10 μ. The filtrate is dried at 130 ° C. and the powder is stored in a plastic container.

The production material provides Al 2 O 3 by 1.5% of the raw material weight and is used to tan the calcined goatskin. If the tanned leather is left overnight, aluminum appears to be consumed 80-82% and the shrinkage temperature is 85 ° C.

Example 10

Four battered pale yellow calf hides weighing 26 kg of fresh raw hide weight are placed in a small laboratory tanning drum. The cross-sectional pH of the baited skin is 8.0.

Baked raw hides are washed with 52000 ml of water for 10 minutes and dried. 520 gms of Basintan DI (phenol condensate from BASF), 260 gms of Bernatan OS (phenol condensate from Color Chemicals), 260 gms of Basyntan FB6 (urea melamine based material from BASF) and 260 gm of Relugan RE (copolymer of BASF) ) Is added to the drum simultaneously with 13000 ml of water. Drum for about 1 hour. Then 260 gms of ruganyl FBO (acid dye from BASF) is added. Drum for 30 minutes. Subsequently, a mixture of eggplants was added to 2600 ml of hot water at 50 ° C, 260 gms of Bernol liqueur PN (eggplants using natural oils from Color Chemicals), 260 gms of Bernol liqueur ASN (synthetic eggplants of Color Chemicals) and 260 gms of Balmol SX- 20 (Bulmer Lowry's synthetic eggplant) is added to the drum. Drum for 1 hour. This is due to the addition of 2600 gms of aluminum syntans invented by Kanthimathi et al (Example 9 disclosed in Indian Patent Application No. Del 88/2002). Drum treatment for 7 hours. The pH of the cross section is 4.0. The leather is washed with 52000 ml of water for 10 minutes, and the wet leather is removed from the drum and suspended.

Example 11

Five battered sheepskin skins with a fresh skin weight of 5.6 kg are generally degreased in small laboratory tanning drums. The grease-free skin has a cross-sectional pH of 8.0.

Grease-free hides are washed with 11200 ml of water for 10 minutes and dried. Place the raw hides in a drum with 5600 ml of water. The pH of the hide is adjusted to 6.0 by adding 190 ml of 10% concentration of formic acid twice at 10 minute intervals. Drum processing is continued for 30 minutes. 508 gm of Basintan DI (phenol condensate from BASF), 254 gm of Bernatan OS (phenol condensate from Color Chemicals), 254 gm of Basintan FB6 (urea melamine based material from BASF) and 254 gm of Lelugan RE (airborne from BASF) A syntans mixture of coalescing material) is added simultaneously to the drum. Drum for about 1 hour. Then a mixture of 127 gms of Cellafast Orange-CGL (metal complex dye dye from TFL) and 127 gms of ruganyl FBO (acid dye from BASF) is added. Drum for 30 minutes. Subsequently, a mixture of eggplants in 1280 ml of hot water at 50 ° C, 254 gms of Bernol liqueur PN (natural oil-based eggplants from Color Chemicals), 254 gms of Bernol liqueur ASN (synthetic eggplants from Color Chemicals) and 254 gms of Balmol SX-20 (The synthetic eggplant of Balmer Lowry Co., Ltd.) was added to the drum. Drum for 1 hour. This is due to the addition of 1778 gm of BCS (based on hide weight). Drum for 8 hours. At the end of tanning the pH is 4.0. The leather is washed with 50800 ml of water for 10 minutes. The treated leather is removed from the drum and laid down.

According to the leather manufacturing process according to an embodiment of the present invention, there are the following effects.

1. According to the leather manufacturing process of the present invention, it is not required to measure with complex control.

2. According to the leather manufacturing process of the present invention, no pickling, basicization, acid washing, recromming and neutralization steps are required.

3. Total solids and chemical oxygen demend (COD) are significantly reduced (see Table 1).

4. The time, power and water required for the leather manufacturing process of the present invention are significantly reduced (see Table 1).

5. According to the leather manufacturing process of the present invention, it is possible to produce leather having softness, smoothness, and other important properties equivalent to those produced by conventional processes (Table 2).

Table 1.Comparison of Process Conditions, Contamination Variables (Factors), Water, Time, and Power Conditions

Table 2. Comparison of the bulk properties of leather treated by the conventional process (C) and the process (E) according to the present invention.

The above value is the mean ± S.D of 10 leathers.

Claims (19)

(a) Delimed and / or batted pellets are treated with 2-6% fatliquor at a temperature of about 20-55 ° C. and pH 5.0-8.5, optionally 1-6% adding synthetic tanning agent (syntan) and dye of w / w, (b) mix the result of step (a) for about 3 hours to obtain fatliquoring raw material, (c) 4-25% w / w of tanning agent pH 5.0-8.5 to the branched raw material of step (b), optionally adding a complexing agent, (d) a new order of leather manufacturing process comprising obtaining the processed wet leather by adjusting the pH of the material obtained in step (c) to 3.5-4.5 for about three hours in a conventional manner. The method of claim 1, Xanthan in step (a) is any one selected from the group of acrylic, phenol condensates, urea condensates, sulfones, melamine, protein condensates or their Leather manufacturing process of a new order that is a combination. The method of claim 1, The dyeing process of step (a) is any one selected from an acid, a metal complex, or a combination thereof. The method of claim 1, The branching process of step (a) is any one selected from the group comprising vegetable, synthetic, semisynthetic branching, or a combination thereof. The method of claim 1, The tanning agent of step (c) is a new order leather manufacturing process selected from the group consisting of base chromic sulfuric acid, vegetable tannin, aluminum syntan or chromium-silica. The method of claim 1, (c) the complexing agent of step (c) is a new order of leather manufacturing process selected from the group consisting of polymer or briquettes. The method of claim 1, In step (a), the percentage of branching added is based on the weight of the fresh raw hide. The method of claim 1, in step (c), the percentage of tanning agent is based on the weight of the fresh skin obtained in step (a). The method of claim 1, A new order of leather manufacturing process wherein the dye of step (a) is about 2%, preferably 1%. The method of claim 1, and (c) the complexing agent of step 2 is a new order of leather manufacturing process. The method of claim 10, and (c) the complexing agent of step 1 is about 1%. The method of claim 1, A new order of leather manufacturing that takes about 6-10 hours to process the leather. The method of claim 1, This process is a new order of leather manufacturing process with more softness, fullness, and graininess than the conventional process of 8.5 ± 2. The method of claim 13, This process is a new order of leather making process with more softness, richness and graininess than the conventional process of 8.2 ± 2. The method of claim 1, A new sequence of leather manufacturing processes in the environment with COD amounts of 10-15 kg / t (raw skin / leather) The method of claim 1, The post tanning process is a new order of leather manufacturing process that does not require pickling, basicization, acid cleaning, recroaming or neutralization. The method of claim 1, The process of manufacturing a new order of leather is completed in about 5 days. The method of claim 1, The new process for producing leather, wherein the water required in the process is 15000-16000 liters / ton (raw skin / leather). The method of claim 1, The new leather manufacturing process of the new order is the power required in the process is 220-500kWh.

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