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Ajouter le résultat dans votre panierTreatment of saltless curing waste using hydrogen peroxide / G. Sekaran in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. LXXXIII (Année 1988)
Titre : Treatment of saltless curing waste using hydrogen peroxide Type de document : texte imprimé Auteurs : G. Sekaran, Auteur ; W. Madhavakrishna, Auteur ; K. Chitra, Auteur Année de publication : 1988 Article en page(s) : p. 5-16 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In the absence of an effective method of treating soak liquor containing sodium chloride, an alternative curing technique for hides and skins using phenol-borax mixture is discussed. The characterization of spent liquor, first soak liquor and second soak liquor is reported. Anaerobic treatment of phenolic waste liquor does not yield the desired results, but treatment with hydrogen peroxide and a catalyst produced good results. The optimum conditions like pH, phenol : H2O ratio, the catalyst (FeSO4, 7 H2O) and phenol concentrations have been arrived at for the maximum removal of phenol. The residual phenol, after treatment with hydrogen peroxide, can be successfully removed using lime under agitation. En ligne : https://drive.google.com/file/d/1dKytCY4aG987tzUEexlb7b0AWZ21oxCx/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8839
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXXXIII (Année 1988) . - p. 5-16[article]Réservation
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Titre : Large scale chrome recovery from chrome wash liquors Type de document : texte imprimé Auteurs : David A. Boast, Auteur Année de publication : 1988 Article en page(s) : p. 17-23 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : A direct liquor chrome recycling system has been successful operating at a South African wet blue tannery for approximately 4 years. For this period, excess chrome liquors (chrome wash liquors, sammying liquors and excess chrome recycle liquors) were discharged into the effluent treatment plant. This paper describes the incorporation of a plant for chrome recovery from these liquors by precipitation, settling out of the chrome sludge, and subsequent re-solubilisation of the chrome in the sludge by acidification.
The supernatant, containing very low concentrations of chrome, replaces the excess chrome liquors that were previously discharged to effluent, thereby reducing the chrome content in the effluent to an absolute minimum. (The supernatant entering the effluent contains <100mg/l Cr2O3). The chromium in the mixed effluent was reduced from 508 mg/l to 54mg/l Cr2O3 on average, after installation of the recovery plant.
The large scale implementation of this system is described, together with the economic and ecological advantages. Approximate net savings, excluding labor and electrical costs, amounted to R206 per day or batch of 1000 hides processed to the wet-blue. This amounts to an annual saving of R51700. At 251working days per annum. (R100 = $49.10 U.S.)En ligne : https://drive.google.com/file/d/1XMpdJk4mjCVHZBiQVqyC8OAhJFL8LM8N/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8840
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXXXIII (Année 1988) . - p. 17-23[article]Réservation
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Titre : Wet process technology IV. Evaluation of an alternative deliming agent Type de document : texte imprimé Auteurs : Maryann M. Taylor, Auteur ; David G. Bailey, Auteur ; Stephen H. Feairheller, Auteur ; P. M. Civitillo Sweeney, Auteur ; Edward J. Diefendorf, Auteur Année de publication : 1988 Article en page(s) : p. 35-45 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Ammonium sulfate is commonly used to delime hides by the United States tanning industry, a practice that results in elevated levels of ammonia in beamhouse effluent. Concern that eventual restrictions on the levels of ammonia permitted in tannery effluent will be difficult and expensive to meet has led to investigations to find alternative. While this substitution effectively lowered the concentration of ammonia in the effluent, the quality of the resulting leather has been questioned. The ability of magnesium to replace ammonia in deliming as reported in the literature was examined at ERRC. While differences were found in the resulting leather, modification of the published process produced an acceptable product. The chemical and physical changes which occurred using magnesium sulfate are compared with data from a standard process developed for converting cattlehides to chrome tanned leather using ammonium sulfate. The proposed modification to the process, the resulting analytical data, and the crust leather evaluations are presented. En ligne : https://drive.google.com/file/d/1Gkqqw3j5BPg-DIiNvARvnN8p3tm72ZH0/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8841
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Titre : Electron beam irradiation of fresh hides, salted hides and leather. Microbial control and effect on physical properties Type de document : texte imprimé Auteurs : David G. Bailey, Auteur ; Michael J. Haas, Auteur Année de publication : 1988 Article en page(s) : p. 46-57 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : This study is the first report of the effects of electron irradiation on the physical properties and microbial activity on fresh and brine cured cattlehides. The results were similar to those found on treatment of raw skins with gamma irradiation which had previously been reported by several laboratories. Samples of fresh hides, brine cured hides and chrome tanned crust leather were irradiated with an electron beam at levels up to 60 Mrads. At a level of 5 Mrads of irradiation microbial activity on fresh hides was eliminated for 28 days. There was a loss in tensile strength and ball burst compared to the control at this level of irradiation. Irradiation of chrome tanned crust leather containing 55 percent moisture at 20 Mrads caused a severe loss in tensile strength relative to the control. Leather with a 16 percent moisture content had less damage. En ligne : https://drive.google.com/file/d/1K8Fq-xy1eSB3ZS6wxtszIzjInBMYhOv_/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8842
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Titre : All-aqueous finishing systems for leather, problems and solutions Type de document : texte imprimé Auteurs : Werner Walther, Auteur Année de publication : 1988 Article en page(s) : p. 74-83 Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Aqueous or hydro-finishes for leather must today meet numerous criteria and requirements :
- Applicable as universally as possible and rational for use with all normal leather types, comparable to organic systems.
- Practicality of application, as far as possible without any modifications to existing equipment or technologies.
- High processing and end-use fastness properties, comparable to those with organic systems(according to DIN norms).
- Good wearing and hygienic end-use properties.
- Elegant,fashionably attractive appearance of the finished product
- Ecological requirement in the widest sens of the term
- Non-flammability of the products
- Non-hazardous from an industrial hygiene standpoint
- Commercial aspects as favorable as possible
All-aqueous systems are problematical from a technical application and qualitative standpoint.
For hydro-finishes, in addition to the traditional protein substances, essentially polyacrylate dispersions,polybutadiene dispersions,polyurethane dispersions and high-grade nitrocellulose emulsions are used. Most recently,cellulose ester emulsions have also come onto the market.
Moreover,combinations of all the above products are processed.
High-quality crosslinking agents based on polyfunctional nitrogen compounds increase the quality of hydro-finishes appreciably.
Today high-grade aqueous finishing systems are applied which meet many of the criteria already mentioned.En ligne : https://drive.google.com/file/d/1HwBfQ7Knz4T8dtrUoqpQKJRCq464fKn0/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8844
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Titre : Waterborne coatings based on different film forming polymers Type de document : texte imprimé Auteurs : Dietrich Lach, Auteur ; Karl Fischer, Auteur ; Ivo Knoll, Auteur Année de publication : 1988 Article en page(s) : p. 87-94 Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : For about 20 years, the problems of environmental protection have been intensively discussed at the congresses of the leather industry in all parts of the world. In the seventies, the effluent problems were of topical interest. In the heighties, the discussions have concentrated more and more on subjects concerning air pollution. The problems of environmental protection have thus shifted from the beamhouse to the finishing department. Requirements of the government agencies are,to a great extent, already in existence. Enforcement of these regulations will make the use of lacquers based on oganic solvent difficult in the future. This means that the traditional finishing system has to be changed completely. Waterborne coatings have therefore to be used for finishing and top coating leather. However, the question is whether this will be possible without impairing the physical properties and the appearance of the finished leather.
Before we discuss this question, let us first take a look at the improvements we can achieve with existing technology. Let us consider a tannery finishing 2000 sides a day using two top coats based on nitrocellulose. These top coats can be applied to the leather in four different ways. They can be sprayed or printed as a nitrocellulose lacquer or they can be sprayed or printed as a lacquer emulsion. Table I shows the approximated amounts of solvents emitted.En ligne : https://drive.google.com/file/d/1WXdsQbn9fi4T8LAzh9MlsKftJEp-5T5D/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8846
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Titre : What's adhesion Type de document : texte imprimé Auteurs : William C. Prentiss, Auteur Année de publication : 1988 Article en page(s) : p. 100-109 Langues : Américain (ame) Catégories : Adhésion Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : There are two purposes for testing the physical properties of finished leather. One is for quality assurance, that is, to be sure production leathers meet the standards established for them. The other is for diagnostic purposes, a problem is uncovered during routine QC testing or a new finish is being developed and performance needs improvement in one or more properties. The property we are discussing is adhesion, the role is diagnotic since we are addressing the problems, and the primary method of test is the Scotch tape method, although I will also discuss other observations which can be made to identify whether an adhesion problem does exist. For the Scotch tape method, there are several adhesion situations which I will address along with some guidelindes for corrective action. En ligne : https://drive.google.com/file/d/1UuPWLAofXiFJWU8vTx5Qe62R-6uO0dxi/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8849
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXXXIII (Année 1988) . - p. 100-109[article]Réservation
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Titre : Fiber orientation and small-deformation modulus of stretched, partially-dried hide Type de document : texte imprimé Auteurs : Paul L. Kronick, Auteur ; Peter R. Buechler, Auteur Année de publication : 1988 Article en page(s) : p. 115-124 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The dynamic, low-deformation, tensile modulus of raw bovine corium was measured in various states of static elongation and dehydration from neutral and low pH. The data were analyzed by comparing the overall change in fiber orientation during stretching, as determined by small angle light scattering, with yhe number of fibers that are pulled straight while subject to interfiber adhesions. The wet rawhide at pH=7, which contained 164 percent water based on dry weight, elongated with little overall fiber orientation, but its modulus increased by two orders of magnitude when stretched by 20 percent, showing the effects of progressive growth in the number of straightened fibers. The modulus at 20 percent elongation increased only 2 fold in the presence of 60 percent (v/v) isopropanol, showing a greater effect of interfiber adhesion, which hindered the movement and straightening of fibers. Within experimental error the maximum values of the moduli of samples in 0%, 60%, and 100% isopropanol, at 20 percent elongation, were the same, showing the equivalence of fiber adhesion. The hide shrank more when solvent-dried from an acid-swollen state (pH=3), but the interfiber adhesion wazs lowered, as seen in the behavior of the fibers when the dried material was stretched. These results explain the properties of solvent-dried hides in terms of the movements of the hide fibers when the dried hide is deformed, and have implications for process design and product quality. En ligne : https://drive.google.com/file/d/1HKP5T3s9tlXm_vI88tkR64jcTKfmHjbk/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8850
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Titre : Determination of spray machine transfer efficiency for leather finishing Type de document : texte imprimé Auteurs : George Stockman, Auteur Année de publication : 1988 Article en page(s) : p. 125-128 Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : A practical of measuring transfer efficiency for the finishing of leather on a spray machine has been demonstrated. Solvent-based lacquer compounded with a copper pigment was sprayed on side leather with and without micro-processor spray controls. Atomic absorptio analysis of the lacquer-pigment miwture and of the leather before and after spraying provides the data from which transfer efficiencies are calculated.
This method can be used to measure the tranfer efficiency of new equipment or to gauge the effectiveness of modifications to existing spray lines. Additional research needs to be conducted to define the affect of different types of finish material and different leather substrates on spray machine transfer efficiency. Similarly, the relative contributions of "overspray" and "bounce-back" need to be further evaluated.En ligne : https://drive.google.com/file/d/102bQa3exh6sI46qwAKsxob0wW3YPlYv5/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8863
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Titre : A study of the histological characteristics of chinese hankow goatskins Type de document : texte imprimé Auteurs : P. Jinshen, Auteur ; W. Shiling, Auteur ; H. Yuixiang, Auteur ; Z. Chuanbo, Auteur ; X. Shiping, Auteur Année de publication : 1988 Article en page(s) : p. 129-143 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : This paper describes the study on the histological structure of the Chinese Hankow Goatskins. By employing the scanning electron microscope (SEM), the transmission electron microscope (TEM), and the light microscope (LM), the authors have observed the samples from various parts and layers of the goatskins. The results show such aspects of the histological characteristics of the skins as the thickness distributio of the skin, the hair and its distribution, the layers in the epidermal area, the fibre variation and interweaving orientation in the dermal area. From the results we cannot only predict the leather characteristics, eg. the grain pattern of the leather from this kind of skin, but also anticipate the problems that may arise in the processing. En ligne : https://drive.google.com/file/d/1MKKuugHQVxD1V4ic79S0zHpUAUxf7VLm/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8864
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Titre : Flavonols, flavones and tanning of parkia clapperoniana Type de document : texte imprimé Auteurs : Raphael O. Adewoye, Auteur ; Olubode O. Ajayi, Auteur Année de publication : 1988 Article en page(s) : p. 153-156 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The fruit husk of Parkia clappertoniana, a tropical plant which belongs to the family of Mimosaceae, constitutes a significant potential source of vegetable tanning agent. The tanning content is about 45%, mainly condensed tannins. Six flavone, tricin, have so far been isolated from the material. En ligne : https://drive.google.com/file/d/1yUwFtYfoAMa0kQMexXoV8W7Ny6jEahnj/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8865
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Titre : Computerization of equipment maintenance Type de document : texte imprimé Auteurs : J. Michael Geaghan, Auteur Année de publication : 1988 Article en page(s) : p. 157-162 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Recently Prime Tanning Co. selected and placed into service a Computerized Maintenace Management System. This paper explains how the system was selected, problems encountered, start up and follow up programs. En ligne : https://drive.google.com/file/d/1lzstzhovwOSyl_LnL_VH7bG9Zo_pDl43/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8866
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Titre : Retannage and retainning materials Type de document : texte imprimé Auteurs : H. Träubel, Auteur ; K. H. Rogge, Auteur Année de publication : 1988 Article en page(s) : p. 193-205 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The change from corrected grain to aniline type leathers in the seventies created new types of retanning materials. These retanning materials had to fulfill the requirements of soft and filled leathers, with good dyeing properties. Different types of retanning products and their basic applications are discussed. En ligne : https://drive.google.com/file/d/1B7LOw2g_ZFZ7MEzNkFhgy5_MiQVZjCB8/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8871
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Titre : Endoparasitic phase of demodex bovis in cattle, I Type de document : texte imprimé Auteurs : R. A. Venkatesan, Auteur ; M. Chandran, Auteur ; P. Richard Masillamony, Auteur Année de publication : 1988 Article en page(s) : p. 211-219 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Presence of demodex bovis has been demonstrated in various body fluids and testicles of adult cattle and also in bovine foetal tissues (neo-natal calf) dead of dystokia in-utero and procured by caesarean operation under aseptic precautions. The parasites are present in the tissue superimposed one over the other in single file, such that the limbs of the individual parasites are arranged in a linear fashion. Alternatively, in certain tissues they appear as "parasite clumps", and within the parasitic clump individual D. bovis lie in a criss-cross fashion. En ligne : https://drive.google.com/file/d/1NQctD6eiG55tXZdBENHvDCw75ZbJlFlX/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8872
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Titre : Comparison of chromium leachability from tannery waste usin EP toxicity and toxicity characteristic leaching procedure methods Type de document : texte imprimé Auteurs : Edward E. Menden, Auteur ; Frank H. Rutland, Auteur Année de publication : 1988 Article en page(s) : p. 220-231 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : A total of 82 samples typical of leather industry solid waste materials was evaluated for chromium leachability by EPA Extraction Procedure Toxicity (EPT) and Toxicity Characteristic Leaching Procedure(TCLP) methods. These samples consisted promarily of wet blue leather trimmings and shavings, dry leather trim scrap, buffing dust and sludge. For acidic materials(pH<5) such as wet blue and dry leather wastes, TCLP extraction was 4-5 times more aggressive than EPT due to the complexing effect of acetate ion. The majority of such materials would exceed a regulatory threshold of 5.0mg/l if based on total Cr rather than CrVI. For alkaline sludge wastes, the difference in EPT and TCLP extraction was quite small, if indeed significant, and a majority of samples was below 5.0mg/l. Chromium leachability from dry leather waste was substantially lower than wet blue, despite higher solids content. Thus, leather drying appears to have a major beneficial effect. Efforts to analyze the effects of moisture level, chromium content and pH were inconclusive, and more work is planned to further clarify their role in chromium leachability. En ligne : https://drive.google.com/file/d/1EzhnP-J6CjvUYgCaLddMIa37E-recmfe/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8873
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Titre : A new look at cationic fatliquors Type de document : texte imprimé Auteurs : Samir Das Gupta, Auteur Année de publication : 1988 Article en page(s) : p. 239-261 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Cationic Fatliquors have been used in the leather industry for a long time, but only as an adjunct to anionic fatliquors,mainly for surface characteristics.
Very few publications give, in quantitative terms, their actual contribution in leather making. In this paper, an attempt has been made to quantify contributions of cationic fatliquors and new ways of applying cationics as primary fatliquors are proposed,particularly for retanned side leather.
Various processes and comparative statistical data on the physical properties of leather, fatliquored primarily with cationic and anionic fatliquors are presented.En ligne : https://drive.google.com/file/d/1P3tvVqRGg1d8go_-5lQuoHTwEKQ0EcIu/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8874
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Titre : Radiation-cured coatings for leather. II. color coats for side leather Type de document : texte imprimé Auteurs : F. Scholnick, Auteur ; Peter R. Buechler, Auteur ; Edward J. Diefendorf, Auteur Année de publication : 1988 Article en page(s) : p. 262-268 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Ultraviolet and electron beam radiation have been used to effect cures of intermediate color coats for side leather. Radiation-curable systems containing inorganic pigments and organic dyes were developed. The effect of variation in type of radiation was studied as well as change in formulation. Physical properties of the finished leather including Taber abrasion, flexibility,adhesion and crock resistance were determined. The radiation-cured coatings were equal or superior to conventional coatings in every respect. En ligne : https://drive.google.com/file/d/1-SCJppJP1mxME70L9zkGjWChUtiM3Xa3/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8875
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Titre : Polyurethane dispersions Type de document : texte imprimé Auteurs : H. Träubel, Auteur Année de publication : 1988 Article en page(s) : p. 317-326 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Dispersions et suspensions
Polymères en émulsion
PolyuréthanesIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : The different types of polyurethane dispersions are presented. Due to the high tensile strengh and abrasion properties, polyurethanes are able to fulfill finish requirements in thin layers. Aniline type finishes with high fastness properties can be obtained if good covering pigments are used in combination with aqueous polyurethane. En ligne : https://drive.google.com/file/d/1wUBunoqgEQwByT2ECSzibWvzDKdbqhhK/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8876
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Titre : Interactions of polyphenols and their derivatives with collagen : a model study of vegetable tannins Type de document : texte imprimé Auteurs : G. C. Na, Auteur Année de publication : 1988 Article en page(s) : p. 337-349 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The interactions of gallic acid,pyrogallol, and the derivatives of pyrogallol with solubilized calf skin collagen were investigated. At pH 2.7, gallic acid, but not pyrogallol, showed binding to solubilized collagen. At neutral pH and 25°C, the color of the pyrogallol solution changed from clear to light brown over a period of several hours, reflecting the auto-oxidation of the phenol groups. Gel column chromatography showed that pyrogallol underwent a series of spontaneous reactions to form products of high molecular weights and changed bound to collagen. At pH 4.0, high concentrations of pyrogallol (0.05-0.15M) in the solution reduced the melting temperature of the soluble collagen, indicating that pyrogallol can compete for the hydrogen-bonding sites and break the interchain interactions. At pH 7.0, pyrogallol, or most likely its derivatives, increased the rate of collagen fibril assembly and stabilized the fibril structure. These results are discussed in light of the leather tanning effects of the polyphenols. En ligne : https://drive.google.com/file/d/1USFjSaNF0_ONU95__KQgsxkUlk8qCbn5/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8877
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Titre : Advantages of application of standard data computers as process controllers in drum automation Type de document : texte imprimé Auteurs : Andrea D. Bocca, Auteur Année de publication : 1988 Article en page(s) : p. 350-354 Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Industrial automation is switching from punched cards to process controllers based on microprocessors. In data management we see a proliferation of personal computers based on microprocessors as a replacement or support to mainframes. An efficient drum automation needs a process controller and a data management device for formulation editing : using a personal computer as process controller we get an easy and economical integration of both functions and complete access to mainframes for useful data interchange. The choice of the personal computer family involves the choice of a working media or environment : this is a matter of vital importance for the safeguarding of the invested capital. En ligne : https://drive.google.com/file/d/1Yo3JgALQ2OjMAa0AqrBFWwr1JWtiyVdW/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8950
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Titre : Chemical modification of collagen for improved chrome tannage Type de document : texte imprimé Auteurs : Stephen H. Feairheller, Auteur ; Maryann M. Taylor, Auteur ; Edward H. Harris, Auteur Année de publication : 1988 Article en page(s) : p. 363-371 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Chrome salts are known to tan by bonding with collagen's side chain carboxyl groups as the primary sites for the crosslinking. As part of a basic study to develop chrome-sparing tannage, additional carboxyl groups have been added to collagen by use of the Michael Reaction.Under these conditions, beta-carboxyethyl acrylate was covalently bonded to existing free amino side chains of collagen. This resulted in a significant improvement in chrome tanning. With equal chrome offerings, the treated hide samples showed lysine and hydroxylysine losses indicating that these amino acid residues are the sites of the reaction with collagen. Physical properties of the leather were determined. En ligne : https://drive.google.com/file/d/1w7pAyA4kthnWevu7pWQhbCMjW0KYccsV/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8951
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Titre : High-strength collagen biomaterials Type de document : texte imprimé Auteurs : Kenneth E. Hughes, Auteur ; David J. Fink, Auteur ; Timothy B. Hutson, Auteur ; Arthur Veis, Auteur Année de publication : 1988 Article en page(s) : p. 372-377 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Described is a new collagen process technology which uses controlled, convection-driven laminar flow to produce oriented fibrillar collagen gels. It was found that,under the correct experimental conditions, collagen could be induced to form oriented gels which can be further processed to yield highstrength ribbons, tapes,filaments and composites. En ligne : https://drive.google.com/file/d/1UGJb5QjMbKo5S5fojklGcrDKFUVLbo1p/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8952
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Titre : The effect of trivalent chromium on anareobic digestion Type de document : texte imprimé Auteurs : C. A. Jackson-Moss, Auteur ; J. R. Duncan, Auteur Année de publication : 1988 Article en page(s) : p. 389-395 Note générale : Biblio. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The effect of trivalent chromium an anaerobic digestion was investigated using a synthetic waste containing glucose as the organic carbon source. It was found that an influent concentration of 5000mg/l trivalent chromium could be tolerated by acclimatized methanogenic bacteria. However,if the concentration in the synthetic waste was further increased, inhibition of the methanogens resulted, with a corresponding decrease in degester performance. These results suggest,therefore, that the concentration of trivalent chromium present in tannery effluents and sludges,which ranges from 1 to 2500 mg/l would have no significant effect on an acclimatized, stable anaerobic digester treating these wastes. En ligne : https://drive.google.com/file/d/1E38LDTW0-AgOjKbRDzj6McPoiHAx8QUn/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8953
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Titre : The occurence of endoparasitic phase of demodex bovis in cattle - II Type de document : texte imprimé Auteurs : R. A. Venkatesan, Auteur ; M. Chandran, Auteur ; A. Koteeswaran, Auteur ; P. Richard Masillamony, Auteur Année de publication : 1988 Article en page(s) : p. 396-405 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : A series of viscera from three different prenatal bovine foetuses and one postnatal calf were procured aseptically from the Veterinary Hospital, Madras Veterinary College, and examined for the presence of Demodex bovis. All the foetal viscera, such as lung, liver, spleen, kidney, brain, spinal cord, intestines, mesenteric lymph glands, testes and skin examined have shown their presence beyond doubt. En ligne : https://drive.google.com/file/d/1lV7n_9muwRmtY87PD-e_IOL9pwRnJD7e/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8958
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Titre : The pros and cons of a hair-save process in the beamhouse Type de document : texte imprimé Année de publication : 1988 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Chaulage
Cuirs et peaux de bovins
Travail de rivière (cuir)Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In recent years, legisltators in many different countries have been pressing ever harder for the treatment of tannery effluents. Apart from the chromium III load, it is the protein Joad from the beamhouse effluents which is seen as a cause for alarm. This protein load consists of dissolved and undissolved substances like hair sludge and machine fleshings, e. g., which result in high COD. A review of the individual process steps quickly showed that the largest quantities of dissolved and undissolved organic substances are obtained during liming. The distribution of the COD values up to tanning inclusive is shown in Fig. 1.
The rising costs of waste water treatment and sludge disposai induced tanners to consider very carefully whether a hair-save liming process could substantially reduce the effluent load. Before we discuss the existing hair-save processes in terms of effluent load, technical outlay and feasibility, let us see whan an optimum hair-save process can achieve.
To answer this question, we took two pieces of cowhide. From one piece we removed the hair mechanically, whereas the other piece was subjected to a conventional hair-burn liming process. The results are shown in Fig. 2. The maximum reduction of the contamin-ants load COD to be expected from an optimum hair-save lime is about 55 - 60%, corres-ponding to an overall reduction of about 30% up to chrome tanning inclusive. Apart from reducing the COD value, however, hair-save processes will also cut down on sulphide, nitrogen and hair sludge.Note de contenu : - Röhm HS-process
- Soaking
- Incubation phase
- Immunization and activation phase
- Hair removal
- Reliming
- Alternatives to a hair-save process
- Fig. 1 : The contribution to the overall COD value of each process step of leather manufacturing (to wet-blue)
- Fig. 2 : Comparison between hair-save and hair-burn liming process in terms of COD values
- Fig. 3 : Formation of Lanthionine by alkaline treatment (immunization)
- Table 1 : Low sulfide hair-saving liming process with hair separation during recycling
- Table 2 : Low sulfide Röhm hair saving liming process with hair separation and splitting
- Table 3 : Typical analytical effluent data from Rohm HS-process and a conventional hair pulping systemEn ligne : https://drive.google.com/file/d/1t4wWzzhjt5zmajJLmYz5j5pCuy9hnwys/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35113
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Titre : Enzymes in the tannery - Catalysts for progress ? Type de document : texte imprimé Année de publication : 1988 Article en page(s) : p. 289-316 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Enzymes Une enzyme est une protéine dotée de propriétés catalytiques. Pratiquement toutes les biomolécules capables de catalyser des réactions chimiques dans les cellules sont des enzymes ; certaines biomolécules catalytiques sont cependant constituées d'ARN et sont donc distinctes des enzymes : ce sont les ribozymes.
Une enzyme agit en abaissant l'énergie d'activation d'une réaction chimique, ce qui accroît la vitesse de réaction. L'enzyme n'est pas modifiée au cours de la réaction. Les molécules initiales sont les substrats de l'enzyme, et les molécules formées à partir de ces substrats sont les produits de la réaction. Presque tous les processus métaboliques de la cellule ont besoin d'enzymes pour se dérouler à une vitesse suffisante pour maintenir la vie. Les enzymes catalysent plus de 5 000 réactions chimiques différentes2. L'ensemble des enzymes d'une cellule détermine les voies métaboliques qui peuvent avoir lieu dans cette cellule. L'étude des enzymes est appelée enzymologie.
Les enzymes permettent à des réactions de se produire des millions de fois plus vite qu'en leur absence. Un exemple extrême est l'orotidine-5'-phosphate décarboxylase, qui catalyse en quelques millisecondes une réaction qui prendrait, en son absence, plusieurs millions d'années3,4. Comme tous les catalyseurs, les enzymes ne sont pas modifiées au cours des réactions qu'elles catalysent, et ne modifient pas l'équilibre chimique entre substrats et produits. Les enzymes diffèrent en revanche de la plupart des autres types de catalyseurs par leur très grande spécificité. Cette spécificité découle de leur structure tridimensionnelle. De plus, l'activité d'une enzyme est modulée par diverses autres molécules : un inhibiteur enzymatique est une molécule qui ralentit l'activité d'une enzyme, tandis qu'un activateur de cette enzyme l'accélère ; de nombreux médicaments et poisons sont des inhibiteurs enzymatiques. Par ailleurs, l'activité d'une enzyme décroît rapidement en dehors de sa température et de son pH optimums.
Travail de rivière (cuir)Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In today's lecture I have attempted to hihglight some of the possibilities that are now available to tanners for exploiting enzymes more effectively in the beamhouse.
Although current enzyme technology is still primarily dependant upon proteolytic en-zymes, better characterisation and more sensitive methods of control can provide the basis for using these products more selectively during soaking and bating, for the production of more specific types of production.
There is now also the opportunity of using selected proteases during chemical unhairing/liming to improve beamhouse processing, based on a clearer understanding of the opening¬up process and the role of proteoglycan. Commercial trials and production runs have now confirmed the viability of Enzyme Assisted Chemical Unhairing under practical conditions and a range of key options are available to the tanner, depending on the priorities of production:
- shortening of liming time
- increased opening-up of the fibre structure and the production of softer leather
- improved pulping and the production of cleaner grains
- reduction of sulphide requirement
- increased area yields
Enzymes can offer considerable potential to the innovative tanner for improving leather processing. There are many new developments currently underway. I hope that I have been able to highlight some of the ways in which enzymes can realistically be catalysts for progress over the coming decade.Note de contenu : - Historical perspective
- Current tannery applications
- Enzyme characterization
- Enzyme assisted chemical unhairing
- Enzyme unhairing
- Soaking enzymes
- Enzyme control
- Fig. 3 : pH activity profiles of a commercial protease measured against different chromogenic substrates representative of the proteins in native hide, compared to the Anson method
- Fig. 4 : Cross-sections showing the difference in enzymatic degradationof elastin in the grain of bovine hide by the commercial protease profile in Fig. 3 when added during
- Fig. 5 : Diagrammatic representation of dermatan sulphate proteoglycal, showing the repeating disaccharide unit of L-iduronic acid and N-acetyl-D-galactosamine-4-sulfate
- Fig. 6 : Regular distribution of dermatan sulphate proteoglycan over the surface of the collagen fibrils in hide and skin
- Fig. 7 : Degradation of dermatan sulphate proteoglycan by strong alkali or proteolytic action during liming. Model of some of the chemical changes that accompany opening-up of the fibre structure
- Fig. 8 : Neck region of crust leather
- Fig. 9 : Cleaner grain surface after liming with enzyme
- Fig. 10 : Wet blue : cleaner grain surface and reduction in growth in enzyme treated sides
- Fig. 11 : Cross-sections of wet blue showing fibre structure and extent of removal of follicle hair
- Fig. 12 : Grainsurfaces of goatskin crust leather
- Fig. 13 : Stability of alkali-stable enzyme in sulphide unhairing/lime liquor (2,3% flake sulphide, 1,5% lime on float, 20°C
- Fig. 14 : Removal of sebaceous grease by enzyme action
- Fig. 15 : Expert workmen classifying calf skins durig and after bating
- Fig. 16 : Detection of grain faults (chemical or mechanical damage) during pre-tanning processing of sheepskins, using a reversible pigment
- Fig. 17 : Identification of enzymes by isoelectric focusing (gel stained with Coomassie blue)
- Fig. 18 : Isometric tension - chemical stabilisation of young skins by oxidising agents in 1600% float (plot for a mature sheepskin in shown for comparison as a solid line)
- Table 1 : Properties of thin bovine clothing leathers (0.6 mm)
- Table 2a : Protein core of dermatan sulphate proteoglycan (a) Amino acid composition (calf skin)
- Table 2b : Protein core of dermatan sulphate proteoglycan (b) NH2-terminal amino acid sequence of protein core of dermatan sulphate proteoglycan
- Table 3 : Dermatan sulphate removal during liming, and physical properties of crust leather
- Table 4 : 24 hour raw -> wet blue process
- Table 5 : Shortening of liming time required for upholstery leather by enzyme assisted unhairing
- Table 6 : Endogenous levels of dermatan sulphate and hyaluronic acid in ovine skin
- Table 7 : Removal of interfibrillary protein from lambskin during soak/scourEn ligne : https://drive.google.com/file/d/1yJ-6ff-FOqCxII6ybCt3roJGRP9HSeZ5/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35114
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