• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    An improved procedure of chromium tanning. The use of water during the manufacture of leather is inevitable, since it is important for the diffusion and distribution of the chemical products in the leather matrix. Because a larger volume of water is used during several unit procedures, the discharge of effluents increases correspondingly with the contaminants. The present invention relates to the prevention of the use of water for a free-picking-basification chromium tanning process. Auxiliary chemicals, such as fatty liquors, are used to improve chrome depletion during the tanning process. In addition, the use of salt and the basification procedure are avoided in the new procedure. The organoleptic and resistance properties of tanned leathers are on a par with those of conventionally processed leathers. This new invention makes an effort to use the water inherent in leather for tanning in order to achieve sustainability with reduced contamination loads. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2632994A1
    申请号:ES201631104
    申请日:2016-08-18
    公开日:2017-09-18
    发明作者:Rathinam ARAVINDHAN；Palanisamy Thanikaivelan；Gladstone Christopher JAYAKUMAR；Palanivel SARAVANAN；Jonnalagadda Raghava Rao
    申请人:Council of Scientific and Industrial Research CSIR；
    IPC主号:
    专利说明:

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    DESCRIPTION
    An improved chrome tanning process Field of the invention
    The present invention relates to an improved chrome tanning process. More particularly, the present invention relates to the realization of the chrome tanning process without the addition of water. The water inherent in the leather is used for chrome tanning. The process employs auxiliary chemical products, such as fatty liquors to improve the distribution and depletion of chromium during the tanning process. In addition, the use of salt and the basification procedure are avoided in the new procedure. The organoleptic properties of tanned leathers are on par with those of conventionally processed leathers. The strength characteristics of raw tanned leathers meet the standard standards, which determine the quality of the final leathers. This new invention makes an effort to achieve sustainability with reduced pollution loads.
    Background of the invention
    A huge volume of water is used during leather treatment, which leads to the discharge of a huge amount of wastewater (Rao et al., Journal of Cleaner Production, 11, 591-599, 2003). Researchers throughout the world are involved in the development of technologies to minimize the use of water in the treatment of leather. Chrome tanning is a method widely used to prepare leathers due to its versatile properties. The use of water during chrome tanning is very important for obtaining a uniform chromium diffusion, distribution and hydrolysis. The chromium liquor used contains 1,500-3,500 ppm of chromium. Chromium discharge represents a major concern and the stipulated standard establishes 2 ppm of total chromium for the discharge of tannery effluents in inland water bodies (Suresh et al., Journal of Cleaner Production, 9, 483-491, 2001). Therefore, alternative technologies are required to reduce chromium contamination or an alternative tanning system to combat the current scenario. Due to the lack of availability of a more suitable alternative tanning agent, it seems more appropriate to continue using trivalent chromium as the main tanning material and it seems logical to manage chromium by reducing contamination at the source or treatment at the end. of the pipe.
    The recycling of the chromium liquor used to the tanning or pickling bath is one of the best chromium management procedures to overcome the problem of chromium contamination
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    (Sreeram et al., The Journal of the American Leather Chemists Association, 100, 233-242, Muralidharan and John, WO 2012153203A1, 2012). However, regular control and supervision of the acidity and salt content of the liquor are necessary. The recovery / reuse methodology is a very simple and effective procedure to combat chromium contamination, which is gaining importance (Sreeram and Ramasami, Resources, Conservation and Recycling, 38, 185-212, 2003). The use of chromium depletion aids, high depletion chrome tanning salts and technologies with less chromium has been developed (Ramamurthy et al., Clean Technologies and Environmental Policy, 16, 647-654, 2014; Van and Brendler., US Patent 7063728B2, 2014).
    Chromium-free tanning-basing is another commercially viable development, in which chromium tanning is performed at a pH higher than about 5.0, without the use of common salt. In addition, basification is not necessary in this procedure (Legesse et al., The Journal of the American Leather Chemists Association, 97, 475-486 2002, Rao et al., The Journal of the American Leather Chemists Association, 99, 82- 94, 2004, John and Muralidharan, patent WO 2012153203A1, 2006). However, the described procedure employs a significant amount of aqueous medium and discharges wastewater with quite low pollution loads compared to conventional pickling based on the chrome tanning system. In addition, researchers are also studying the use of an alternative means to water during the chrome tanning procedure. Silambarasan et al. (RSC Advances, 5, 6681566823, 2015) have shown that chromium tanning can be carried out in ethanol and its derivatives instead of water. Similarly, there are reports of the use of pressurized carbon dioxide as a means for chromium tanning (Manfred et al., The Journal of Supercritical Fluids, 66, 291-296, 2012). A recent study shows that a minimum of 55-65% internal moisture content is required within the collagen matrix for the manufacture of chrome-tanned leathers with comparable quality (Silambarasan et al., Journal of Cleaner Production, 87, 567-572, 2015).
    As can be seen in the prior art, current knowledge about cleaner chrome tanning procedures, as well! Like other chrome management options it is well known. The prior art focused on technologies such as an alternative tanning system, without stabbing and the use of an alternative means in chrome tanning. The recovery and recycling of used liquor are also practiced in some industries. However, the generation of chromium-containing wastewater remains an important challenge for leather manufacturers. In addition, the availability of quality water sources for chrome tanning is also increasingly scarce. Therefore, there is a
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    imperative need to provide a chrome tanning system without water.
    Objects of the invention
    The main objective of the present invention is to provide a chrome tanning process without water, which exceeds the limitations indicated above.
    Another objective of the present invention is to use the water inherent in the leather for chrome tanning.
    Yet another objective of the present invention is the use of auxiliary chemical products, such as acid-stable cationic fatty liquors, during the chrome tanning process.
    Still another objective of the present invention is the use of organic acids to adjust the pH before tanning to chromium.
    Still another objective of the present invention is to improve chromium absorption.
    Still another objective of the present invention is to reduce contamination and toxic chemicals in the effluent.
    Yet another objective of the present invention is to provide physical resistance characteristics to leather similar to those of conventional chrome tanned leather.
    Still another objective of the present invention is to reduce the processing time for chrome tanning, as compared to conventional processing.
    Still another objective of the present invention is to eliminate the basification procedures compared to conventional processing.
    Summary of the invention
    Accordingly, the present invention provides an improved chrome tanning process, which comprises
    I. Treat the skin / skin discarded with between 0.5 and 1.5% organic acid in the presence of between 40 and 60% water to adjust the pH in the range of 4.8 to 5.8 ,
    II. drain the floating layers and treat the leather / skin, as obtained in step (i), with between 0.5 and 2.0% of conventional fatty liquor during a period ranging from 20 to 60 minutes
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    III. treating the leather / skin, as obtained in step (ii), with between 5 and 8% of conventional chrome tanning agent, added one or more times, during a period in the range between 240 and 360 minutes to get chrome tanned leather.
    In one embodiment of the present invention, the organic acid used can be selected from formic acid, acetic acid, oxalic acid, individually or in different combinations.
    In another embodiment of the present invention, the conventional fatty liquor used may be selected from cationic fatty liquor, acid stable fatty liquor, universal fatty liquor, chromium stable fatty liquor, individually or in different combinations.
    Detailed description of the invention
    The invention is described below in detail.
    The discarded leather / skin is treated with between 0.5 and 1.5% organic acid in the presence of 40-60% water. The pH of the leather is adjusted in the range of 4.8 to 5.8. After achieving the pH, the floating layers are drained and the leather / skin is treated with between 0.5 and 2.0% of conventional fatty liquor. After a period of 20 to 60 minutes, the leather / skin is treated with between 5 and 8% of conventional chrome tanning agent, added one or more times, during a period in the range of 240 to 360 minutes Check that the pH is in the range of 3.6 to 4.4 to obtain chrome tanned leather.
    The inventive stage of the present invention resides in the utilization of the internal moisture content of the raw material for chromium tanning to reduce the discharge of effluents. In addition, the elimination of common salt and a considerable reduction in the water requirement, the duration and the cost of the process are achieved in the new invention.
    The following examples are provided by way of illustration only and, therefore, should not be construed as limiting the scope of the present invention.
    Example 1
    A disembodied leather weighing 1.5 kg was treated with 7.5 g of formic acid diluted with 75 ml of water and treated in a drum in the presence of 600 ml of water. The pH of the leather was found to be 4.8. After obtaining the pH, the floating layers were drained and the leather was treated with 7.5 g of acid-stable fatty liquor. After a period of 20 minutes, the leather was treated with 75 g of conventional chromium tanning agent (BCS) added in 2 feeds with an interval of 30 minutes over a period of 240 minutes. The pH was found to be 3.6 to obtain chrome tanned leather.
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    Example 2
    Three disembodied leathers weighing 5 kg were treated with 50 g of acetic acid diluted with 500 ml of water and treated in a drum in the presence of 2.5 l of water. It was found that the pH of the leather was 5.0. After obtaining the pH, the floating layers were drained and the leathers were treated with 50 g of cationic fatty liquor. After a period of 45 minutes, the leathers were treated with 350 g of conventional chromium tanning agent (BCS) added in 3 feeds with an interval of 30 minutes over a period of 300 minutes. The pH was found to be 3.8 to obtain chrome tanned leather.
    Example 3
    Two disembodied leathers weighing 3 kg were treated with 45 g of acetic acid diluted with 450 ml of water and treated in a drum in the presence of 1.8 l of water. It was found that the pH of the leather was 5.8. After obtaining the pH, the floating layers were drained and the leathers were treated with 60 g of universal fatty liquor. After a period of 60 minutes, the leathers were treated with 240 g of conventional chromium tanning agent (BCS) added in 4 feeds with an interval of 30 minutes over a period of 360 minutes. The pH was found to be 4.4 to obtain chrome tanned leather.
    Example 4
    Four disembodied leathers weighing 10 kg were treated with 100 g of acetic acid diluted with 1 l of water and treated in a drum in the presence of 6 l of water. It was found that the pH of the leather was 5.0. After obtaining the pH, the floating layers were drained and the leathers were treated with 100 g of cationic fatty liquor. After a period of 30 minutes, the leathers were treated with 600 g of conventional chromium tanning agent (BCS) added in 2 feeds with an interval of 30 minutes over a period of 300 minutes. The pH was found to be 4.0 to obtain chrome tanned leather.
    Example 5
    Two disembodied leathers weighing 6 kg were treated with 60 g of oxalic acid diluted with
    600 ml of water and were treated in a drum in the presence of 3.6 l of water. It was found that the pH
    of the leather was 5.2. After obtaining the pH, the floating layers were drained and the leathers
    They were treated with 60 g of chromium stable fatty liquor. After a period of 60 minutes, the
    leathers were treated with 360 g of conventional chrome tanning agent (BCS) added in 3
    feeds with an interval of 30 minutes over a period of 240 minutes. It was checked
    that the pH was 4.4 to obtain chrome tanned leather.
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    Example 6
    A disembodied leather weighing 1 kg was treated with 10 g of oxalic acid diluted with 50 ml of water and treated in a drum in the presence of 400 ml of water. The pH of the leather was found to be 4.8. After obtaining the pH, the floating layers were drained and the leather was treated with 5 g of cationic fatty liquor. After a period of 30 minutes, the leather was treated with 60 g of conventional chromium tanning agent (BCS) added in 2 feeds with an interval of 30 minutes over a period of 240 minutes. The pH was found to be 4.4 to obtain chrome tanned leather.
    Example 7
    Three disembodied leathers weighing 6 kg were treated with 30 g of acetic acid and 30 g of formic acid diluted with 900 ml of water and treated in a drum in the presence of 3.6 l of water. It was found that the pH of the leather was 5.2. After obtaining the pH, the floating layers were drained and the leathers were treated with 30 g of acid stable fatty liquor and 30 g of chromium stable fatty liquor. After a period of 60 minutes, the leathers were treated with 360 g of conventional chromium tanning agent (BCS) added in 2 feeds with an interval of 30 minutes over a period of 240 minutes. The pH was found to be 4.2 to obtain chrome tanned leather.
    Advantages of the present invention
    The main advantages of the present invention include:
    1. Utilization of the inherent moisture present in the skin discarded for tanning
    2. Elimination of the use of the processing water during the chrome tanning procedure
    3. Reduction of the pollution burden for the environment
    4. Reduction of processing time
    5. A suitable procedure for all types of raw material
    6. Production of soft and flexible leather
    权利要求:
    Claims (3)
    [1]

    1. An improved chrome tanning process, comprising:
    I. Treat the skin / skin discarded with between 0.5 and 1.5% organic acid in the presence of between 40 and 60% water to adjust the pH in the range of 4.8 to 5.8 ,
    5 II. drain the floating layers and treat the leather / skin, as obtained in step (i), with between 0.5 and 2.0% of conventional fatty liquor during a period ranging from 20 to 60 minutes
    III. treating the leather / skin, as obtained in step (ii), with between 5 and 8% of conventional chrome tanning agent, added one or more times, during a period 10 in the interval between 240 and 360 minutes to get chrome tanned leather.
    [2]
    2. Improved process according to claim 1, wherein the organic acid used is selected from formic acid, acetic acid, oxalic acid, individually or in different combinations.
    [3]
    3. Improved process according to claim 1, wherein the conventional fatty liquor used is selected from cationic fatty liquor, acid stable fatty liquor, fatty liquor
    universal, chromium stable fatty liquor, individually or in different combinations.
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    EP0994195A2|1998-10-14|2000-04-19|IBEJI -Investimentos e Servicos LDA.|Process for waterproofing chromium tanned bovine hides|
    WO2004015148A1|2002-08-09|2004-02-19|Rhodia Poliamida E Especialidades Ltda.|Process of tanning hide|
    US20050138738A1|2003-12-25|2005-06-30|Subramani Saravanabhavan|Transposed process for making leather|
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    CN105063253A|2015-08-10|2015-11-18|四川大学|Salt-free high-chrome-absorption chrome tanning method for animal skin and application of salt-free high-chrome-absorption chrome tanning method|
    法律状态:
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