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Assessment of vegetable tannin extracts by colorimetry / Timothy D. Stilwell in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVI, N° 6 (06/2001)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVI, N° 6 (06/2001) . - p. 192-204 Titre : Assessment of vegetable tannin extracts by colorimetry Type de document : texte imprimé Auteurs : Timothy D. Stilwell, Auteur ; Bruce W. Buehrig, Auteur ; Robert J. Harvey, Auteur ; L. Shepley Hermann, Auteur ; Jean J. Tancous, Auteur Année de publication : 2001 Article en page(s) : p. 192-204 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Spray-dried, untreated wattle and treated quebracho extracts were tested for color by four laboratories equipped with Lovibond Tintometers. A comparison of color readings was conducted at the U.S.H.S.L.A. Laboratory where more reasonably priced meters, a Jenway Colorimeter and a Milton-Roy Spectrophotometer, were used. Time for testing was shortened considerably because preliminary tannin analyses were not done and the meters were simpler to operate. Samples of extracts were weighed, dissolved in distilled water, heated to 82oC, cooled and read immediately. A ratio, constructed by dividing yellow readings by red readings, was found to be a valuable method for understanding factors that influence color such as pH and addition of reagents. En ligne : https://drive.google.com/file/d/149LW5NP9yrPYRBQMilRHVQ4FIsZpsm8H/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4371 [article]

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The use and subsequent treatment of surfactants for leather processing / Rumon A. Hankey in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVI, N° 6 (06/2001)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVI, N° 6 (06/2001) . - p. 205-213 Titre : The use and subsequent treatment of surfactants for leather processing Type de document : texte imprimé Auteurs : Rumon A. Hankey, Auteur ; V. L. Addy, Auteur ; K. Senior, Auteur ; D. A. Langridge, Auteur ; Warren Bowden, Auteur ; W. Scholz, Auteur Année de publication : 2001 Article en page(s) : p. 205-213 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The appropriate choice of the type of surfactant for degreasing is very important. In today's environment, pressures from 'green' issues limit the choice of type of degreaser used. The method of comparing degreasers for use in bovine soaking and liming systems is discussed along with the screening of suitable alternatives to Nonyl Phenol Ethoxylate based degreasers. The volume of the grease emulsion in the waste water can be reduced by the use of ultrafiltration. Alkyl phenol ethoxylates function as effective surfactants. More specifically, nonyl phenol ethoxylates (NPE) exhibit excellent wetting and emulsification properties which has resulted in their use as cost effective detergents for the leather industry. Recently, however, their use has been questioned due to environmental concerns. The objective of this study was, therefore, to evaluate commercially available alternative surfactants to nonyl phenol ethoxylate (NPE) based products for the removal of dermal fat from bovine hides. The performance of the surfactants was tested, initially using a model system based on extracted bovine subcutaneous lipid. Subsequently the best four products (tested under the conditions of the assay) were evaluated in small-scale trials. The assay system proved effective for differentiating between good and poor emulsifiers of bovine fat. Four products were selected for exhibiting performance equal to the NPE based products.These products were subsequently evaluated in soaking and liming trials in the production of bovine wet blue. Each of the surfactants gave performance equivalent to that given by the NPE based products. However, the levels of intra-dermal fat were low, in the region of 1.0% and meaningful quantitative analysis was therefore difficult. This suggests that problematic degreasing in bovine processing may originate from poorly fleshed hides rather than residual intra-dermal fat. There was no evidence of redeposition of fat into the wet blue. In conclusion, a number of surfactant products that give acceptable removal of hide fat and contain no NPE have been identified. Their use in full-scale production has not been evaluated within the scope of this project. Two techniques for determining the amount of surfactant present in liquors and leather have been evaluated and developed. The combination of these analytical techniques may enable further optimisation of processes with a view to allowing an overall reduction in offers of surfactants used. The treatment of surfactants in the waste water treatment plant is difficult. Progress has been made by the use of ultrafiltration to remove up to approximately 90% of grease-emulsion from waste streams. En ligne : https://drive.google.com/file/d/1tGm3R7dvS2HHvAyZLPsZToUHFHE84FP-/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4372 [article]

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Live cattle value based on phenotypic characteristics as related to hide quality / L. N. Patterson in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVI, N° 6 (06/2001)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVI, N° 6 (06/2001) . - p. 214-221 Titre : Live cattle value based on phenotypic characteristics as related to hide quality Type de document : texte imprimé Auteurs : L. N. Patterson, Auteur ; R. T. Ervin, Auteur ; A. D. Herring, Auteur Année de publication : 2001 Article en page(s) : p. 214-221 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Members of the leather industry have historically attempted to acquire high quality hides for leather. Several industry groups have encouraged cattle producers to alter management practices to accomplish this goal. However, progress toward this objective has not been realized. There has been some speculation that producers do not receive any financial signals that should motivate them to increase the quality of the hide. The objective of this study was to determine if monetary incentives exist for branded vs. non-branded, and horned vs. polled cattle in current cattle markets. Random pens of cattle were sampled at four area livestock auction facilities located at Roswell and Clovis, New Mexico, and Amarillo and San Angelo, Texas. Data were collected on phenotypic characteristics considered to influence live cattle values. Data analysis indicates that a premium, of $1.72 per hundredweight, is paid for cattle with native as opposed to branded hides (P<0.001). Results of this research also demonstrate that the premium paid to producers for polled animals rather than horned is $1.42 per hundredweight (P=0.0001). En ligne : https://drive.google.com/file/d/1v_8V__fpBuk63olzK5lXlQ0C-2QNsJo5/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4373 [article]

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Approach towards zero discharge tanning : exploration of NaOH based opening up method / Palanisamy Thanikaivelan in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVI, N° 6 (06/2001)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVI, N° 6 (06/2001) . - p. 222-233 Titre : Approach towards zero discharge tanning : exploration of NaOH based opening up method Type de document : texte imprimé Auteurs : Palanisamy Thanikaivelan, Auteur ; T. Ramasami, Auteur ; Balachandran Unni Nair, Auteur ; Jonnalagadda Raghava Rao, Auteur Année de publication : 2001 Article en page(s) : p. 222-233 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Beam house processes are known to contribute 60-70% of the total pollution load in leather processing. The chemicals, namely sodium sulphide and lime, were not quantified and employed without proper rationale. Lime has a potential to drive swelling in a gradual manner due to its low solubility but lacks in environmental concern. Huge amounts of lime sludge and total solids formation are the main drawbacks of lime. In an earlier attempt, lime has been totally avoided for dehairing purpose. However, lime has been indispensable for the purpose of opening up of fibre bundles. Sodium hydroxide for this purpose was thought to be an improper choice due to its high alkaline nature. In this investigation an optimum concentration (1.0% offer at 350% float) of sodium hydroxide has been established for optimal opening up of fibre bundles. This has been substantiated through scanning electron microscopic, spent alkali liquor and pelt analysis, softness measurements and stratigraphic chrome distribution analysis. Performance of the leathers is shown to be on par with conventionally treated leathers through physical and hand evaluation. Especially softness of the leathers is numerically proven to be comparable with that of control. The process also enjoys elimination of deliming process coupled with a 45% reduction in total solids load on environment. En ligne : https://drive.google.com/file/d/1FMDazk_Ue4XcI_64aCdPZPIZDhE5qDlW/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4374 [article]

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