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The replacement of nonylphenol ethoxylates (NPEs) as degreasing agents in wet blue manufacture / George Stockman in WORLD LEATHER, Vol. 18, N° 6 (10/2005)  

[article]  inWORLD LEATHER > Vol. 18, N° 6 (10/2005) . - p. 25-27 Titre : The replacement of nonylphenol ethoxylates (NPEs) as degreasing agents in wet blue manufacture Type de document : texte imprimé Auteurs : George Stockman, Auteur ; Ravindran Rangarajan, Auteur ; Dean Didato, Auteur Année de publication : 2007 Article en page(s) : p. 25-27 Langues : Anglais (eng) Catégories : Cuirs et peaux -- Dégraissage Nonylphenol éthoxylates Produits chimiques -- Suppression ou remplacement Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Alkylphenols (APs) are chemical compounds used mainly to manufacture alkylphenol ethoxylates (APEs); APEs have been used for more than 50 years and are important to a number of industrial processes. This includes pulp and paper, textiles, coatings, agricultural pesticides, lube oils, fuels, metals, plastics, and leather. The industrial applications comprises 55% of the total APE market. Other uses are mostly in industrial, institutional, and household cleaning products. Note de contenu : - The chemistry of nonphenol ethoxylates - Environmental and regulatory issues surrounding NPEs - NPEs application in leather manufacture - Alternatives to NPEs - LAEs' leather degreasing performance - Moving forward : embracing "clean" technologies - Panel 1 : Nonylphenol - Panel 2 : Nonylphenol ethoxylate - Panel 3 : Comparative biodegradability of a LAE and a typical NPE - Panel 4 : Performance of LAE (+/- lipase) for degreasing in comparison with NPE - Panel 5 : Comparison of different categories of degreasing agents En ligne : https://drive.google.com/file/d/1h_L0BMlWRgLFvniRhd0bZ8NUrSuzyD9q/view?usp=drive [...] Format de la ressource électronique : pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=32474 [article]

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Removing phospholipide from hides : Looking back on a "New Perspective on Wet Processing" / Alan Cecil in WORLD LEATHER, Vol. 18, N° 6 (10/2005)  

[article]  inWORLD LEATHER > Vol. 18, N° 6 (10/2005) . - p. 33-35 Titre : Removing phospholipide from hides : Looking back on a "New Perspective on Wet Processing" Type de document : texte imprimé Auteurs : Alan Cecil, Auteur Année de publication : 2007 Article en page(s) : p. 33-35 Langues : Anglais (eng) Catégories : Chaulage Formulation (Génie chimique) Peaux brutes Phospholipides -- Elimination Sébum Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The paper "New perspective on wet processing" was published in World Leather October/November 1993, in which the advantages offered by the removal of phospholipids were discussed. It is a curious fast that the advantages offered by a new development are sometimes so restricted by established practices that the technology becomes marginalised. In the situation described, the gains in surface area became problematic in machine operation, the removal of unwanted hide components created increased effluent charges, and improvecl wet blue properties increased chemical costs. At that Lime the advantages were judged against the disadvantages and found to be lacking. Given that the value of rom/ hides and leather seing prices - strongly influenced by area and quality - are so important to the tanner, perhaps it is rime to re-evaluate this technology. Note de contenu : - The structure of sebum - Different wet blue behaviour - Success, but requiring change - Problems and opportunities - Fig. 1 : Enzyme use within formulations - Fig. 2 : Outline formulate for phospholipids - Fig. 3 : Outline formulae for triglycerides - Table : Outline processes : Liming of domestic wet salted hides En ligne : https://drive.google.com/file/d/11J2gJYjRO3VkNs42CmWX_3lABcPJoCu3/view?usp=drive [...] Format de la ressource électronique : pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=32479 [article]

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Process vessels : effects within chemical processing / Richard Daniels in WORLD LEATHER, Vol. 18, N° 6 (10/2005)  

[article]  inWORLD LEATHER > Vol. 18, N° 6 (10/2005) . - p. 36-37 Titre : Process vessels : effects within chemical processing Type de document : texte imprimé Auteurs : Richard Daniels, Auteur ; Walter Landmann, Auteur Année de publication : 2007 Article en page(s) : p. 36-37 Langues : Anglais (eng) Catégories : Peaux brutes Traitement chimique Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The relationship between the processing vessel, raw mate rials and chemical procedure is intimate. Ultimately rhe needs of hides and skins within wet processing are developed—and limited—by the characterisrics of rhe vessel. The most common pieces of equipment are drums, but significant differences in behaviour are found within the wide range of processing vessels that are available. Notwithstanding, must variations can be understood by considering effects common to drum and paddles. These include combinations that relate to the float level and mechanical action, the movement of hides and skins, and the distribution of chemicals. Note de contenu : - Float levels and mechanical action : The need for good penetration - Shape and movement : The teasing action of pegs - Minimising tangling and formation of knots - The uniform application of force - The distribution of chemicals - The value of cross-circulation - Balancing quality and efficiency - Addressing the limitations of raw materials - Additional information - Panel 1 : The benefits of processing pieces of uniform shape - Panel 2 : Mechanical action to suit the changing needs of hides and skins En ligne : https://drive.google.com/file/d/1LwTW95n7AiLH-EVGYviX7JXFQFLHwWzR/view?usp=drive [...] Format de la ressource électronique : pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=32480 [article]

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How to make perfect patent leather / Peter Jessop in WORLD LEATHER, Vol. 18, N° 6 (10/2005)  

[article]  inWORLD LEATHER > Vol. 18, N° 6 (10/2005) . - p. 39-42 Titre : How to make perfect patent leather Type de document : texte imprimé Auteurs : Peter Jessop, Auteur Année de publication : 2007 Article en page(s) : p. 39-42 Langues : Anglais (eng) Catégories : Cuirs et peaux -- Finition Essais dynamiques Flexion (mécanique) Vernis Vernis en phase aqueuse Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Patent leathers are currently fashionable. When demand is strong, as is the case today, tanners and finishing units that have the expertise to produce leather finished with a well proven patent coating system will have experienced and overcome the many application and performance difficulties that are associated with this type of finish. The original patent leather finishing process that was developed and introduced into commercial manufacture during the latter part of the ni neteenth century used a linseed oil based lacquer coating. This process produced finished leather having the desired high gloss, "plastic" surface. Physical performance was adequate initially but the finish hardened on ageing, resulting in a tendency to crack. Technology has moved since Chose days but the so-called "genuine patent leather" produced today is finished using solvent dilutable polyurethane solutions that are cured using isocyanate based crosslinkers. Water based products are now available that will produce what are termed "wet look" finishes. These products are relatively easy and safe to apply and overcome many of the difficulties and hazards associated with the well-tried solvent based systems. However, they still fall slightly short on the depth of transparency and lustrous gloss level when compared with that of the solvent based systems. Whilst it is the final top coat applied to the leather that determines its gloss level, there are many additional factors that determine the quality, physical performance, consistency and look of the finished leather. Note de contenu : - Making patent leather - Creating a clear, smooth, glossy and glass-like look : Preparation of the crust leather - Impregnation - Base coat - The intermediate coat - Patent top coat - Drying and curing conditions - Handling - Troubleshooting problems - Overall - Panel 1 : Finish peeling off the toe of a shoe on ageing - Panel 2 : Finish peeling off the upper of a shoe on ageing - Panel 3 : Finish cracking on lasting - Panel 4 : Troubleshooting and solutions - Panel 5 : Testing patent leather for flex resistance En ligne : https://drive.google.com/file/d/1cfE5J0MRh-e_X5rhpzZa7VL_KYtxarCK/view?usp=drive [...] Format de la ressource électronique : pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=32481 [article]

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The diffusion barrier within the unhairing process / Carlos S. Cantera in WORLD LEATHER, Vol. 18, N° 6 (10/2005)  

[article]  inWORLD LEATHER > Vol. 18, N° 6 (10/2005) . - p. 29-32 Titre : The diffusion barrier within the unhairing process Type de document : texte imprimé Auteurs : Carlos S. Cantera, Auteur ; Maria Laura Garro, Auteur ; M. L. Goya, Auteur ; L. Barbeito, Auteur ; Betina Galarza, Auteur Année de publication : 2007 Article en page(s) : p. 29-32 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Epilage Peaux brutes Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Hair-saving processes for bovine hides are being applied in tanneries in several countries to replace traditional hair burning systems. The factors that are taken into account when using this unhairing technique are : - the need for a pelt that is suitable for the production of different types of leather - a reduction in the effluent load arising from the beamhouse - the recovery of the partially degraded hair as a solid waste with potential industrial applications It is well known that the organic matter, the sulfide ion content and the presence of suspended solids in the liquid effluent is greatly dependant on the unhairing process employed. Within the sulfide unhairing system there are problems associated with toxicity, odour and effluent treatment. Hydrogen sulfide is a highly toxic gas, and can be liberated from within the unhairing process and from effluent treatment. In extreme cases it has led to the death of workers, and in the wider environment creates an odour within the tannery surroundings which causes associated complaints. The acceptable maximum concentration in the work environment, in which a worker can remain for 8 hours/day and 5 days/a week, is 10 cm3 H2S/m3 (15 mg/m3) without suffering physical damage. The enzymatic removal of intact hair offers a suitable alternative to destructive sulfide unhairing. However, interest in the enzyme unhairing process cornes and goes. This is because of difficulties in managing the process, mainly because the proteolysis cannot be accurately focused and controlled. Essentially, the enzyme activity is not restricted to the function of hair removal, but also affects the structure of the dermis. The grain layer is therefore partially digested hence there is a decrease in the quality of the grain structure in the final leather. Enzyme unhairing remains a fascinating concept, but is full of difficulties. Nevertheless, the problems and costs of treating effluent to acceptable standards are considerable. If hair could be removed intact without using sulfide, then there would be a significant easing of techniques, capital equipment and power requirements to achieve discharge limits. In addition, the volume of sludge would be considerably reduced, with the hair remaining as a new clean raw material with many potential ourlets. Note de contenu : - The epidermis as a diffusion barrier - The role of lipids within the epidermis - The diffusion of substances across the epidermis - Enhancers for penetration, or promoters for reactions : Sodium sulfite - Surfactants - Proteolytic enzymes - Trypsin - Urea - Organic solvents - Phases of the unhairing process En ligne : https://drive.google.com/file/d/14I1LkOfYwz-xkhH5GSFeR0kmgJqXd9Yb/view?usp=drive [...] Format de la ressource électronique : pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35688 [article]

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The milling drum - from blunt instrument to sophisticated process vessel in WORLD LEATHER, Vol. 18, N° 6 (10/2005)  

[article]  inWORLD LEATHER > Vol. 18, N° 6 (10/2005) . - p. 45-48 Titre : The milling drum - from blunt instrument to sophisticated process vessel Type de document : texte imprimé Année de publication : 2007 Article en page(s) : p. 45-48 Langues : Anglais (eng) Catégories : Cuirs et peaux -- Appareils et matériels Cuirs et peaux -- Foulonnage Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The purpose of dry milling is principally to restore the softness and suppleness to leather alter drying or surface finishing operations. This is achieved simply by tumbling the pack of leather for several hours in a drum, normally equipped with plain internai shelves. The repeated tumbling and flexing of the leather frees loose fibres and dust from the flesh side. Early milling drums were normally wooden, sometimes with numerous holes drilled in the circumference to allow the dust to escape, and sometimes of slatted construction, to achieve the same end. The release of the dry dust around the drum made for a very dirty working area, and was a considerable fire risk. Simple dust extraction systems were developed, with an external fan drawing dust-laden air through a hollow axle and into a separation cyclone for collection. Wooden drum drives were normally by ring gear and pinion, and horribly noisy. Re-humidification of the leather was sometimes carried out by injecting low pressure steam via a hollow axle, but this was a hit-or-miss affair, and could often result in irregular wet patches on the leather. So-called "stuffing" drums (Figure 1) were used with some types of leathers, with hot air blown through the hollow axles to aid the re-impregnation of the leather with oils and greases as it was tumbled in the drum. Note de contenu : - Stainless steel construction - PLC control - Non-cylindrical vessels - Automated loading & unloading En ligne : https://drive.google.com/file/d/1HE_h8FhC-ytxcpSx8-rlERwDFMrCk8ac/view?usp=drive [...] Format de la ressource électronique : pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35689 [article]

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