Leather property : looseness / Karl Flowers in INTERNATIONAL LEATHER MAKER (ILM), N° 37 (09-10/2019)  

[article]  inINTERNATIONAL LEATHER MAKER (ILM) > N° 37 (09-10/2019) . - p. 30-33 Titre : Leather property : looseness Type de document : texte imprimé Auteurs : Karl Flowers, Auteur Année de publication : 2019 Article en page(s) : p. 30-33 Langues : Anglais (eng) Catégories : Cuirs et peaux -- Propriétés mécaniques Cuirs et peaux -- Propriétés physiques Cuirs et peaux de bovins Relachement (mécanique) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The fine or coarse wrinkles that appear on the grain side of a leather bent concavely are known in the tanning community as looseness. A leather with the absence of wrinkles will be described as a tight-grained leather. A leather with large, coarse wrinkles that develop particularly with time will be described as loose-grained leather. The leather technologist focusses on two main leather-maldng layers : the grain (corium minor) and the corium (corium major). The transition from the grain to the corium is hypothetically dealt with by a zone known as the grain-corium junction. Many scientists attribute this zone, in bovine leather, as the horizontal zone at the base of the hair follicles. Many animal types exhibit differing degrees of looseness and this is often due to the presence of dermal fat. The removal of that fat during the leather-making process will leave the material porous and prone to loose-grain in the final leather article. The density and proximity of the leather fibres also plays a major role in the natural tendency/ aversion to loose-grain. The belly/axillae region of the hide and skin (a naturally loose structured area) tend to have poor grain tightness. An exaggerated opening up during the beamhouse will increase the incidence of the looseness, particularly in some animais (e.g. buffalo). The heart of the looseness problem is twofold : the looseness can develop during wear, with extremes including delamination of the grain away from the corium; the leather is already loose - but unevenly loose - making the cutting of the leather article difficult to match (in terms of consistent visual pattern). Many leathers, such as floating grain leathers and other mill-grain effects, are intentionally loose in grain structure. Note de contenu : - Beam theory - Looseness testing - Fig. 1 : Tigh-grained leathers bending in on the grain. Blue arrows showing long extension and yellow arrows showing compression of the grain. Modified from Haines and Barlow (1975) - Fig. 2 : Loose-grained leathers bending in on the grain. Blue arrows showing lower extension and yellow arrows showing compression of the grain. Modified from Haines and Barlow (1975) - Table 1 : An outline of some of the techniques to measure leather tightness En ligne : https://drive.google.com/file/d/1b_KDRs5_dLuT-7RDDJlW4ZGIAgJMctkI/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=33621 [article]

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Tying up loose ends / Geoff Holmes in LEATHER INTERNATIONAL, Vol. 217, N° 4863 (08/2016)  

[article]  inLEATHER INTERNATIONAL > Vol. 217, N° 4863 (08/2016) . - p. 17-18 Titre : Tying up loose ends Type de document : texte imprimé Auteurs : Geoff Holmes, Auteur ; Sujay Prabakar, Auteur ; Thijs van Stiphout, Auteur ; Petrik Galvosas, Auteur Année de publication : 2016 Article en page(s) : p. 17-18 Langues : Anglais (eng) Catégories : Collagène -- Détérioration Cuirs et peaux -- Analyse Cuirs et peaux -- Défauts Fleur du cuir Relachement (mécanique) Relaxometrie par résonance magnétique nucléaire Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The authors of this article have observed some excessive plumping in the flanks of limed split hides that has been correlated to looseness in crust leathers. But these observations only accurately predict downgrading in less than 30% of the hides we have pulled from production and processed through to leather, suggesting a tenuous connection at best. We have also seen a strong correlation between sammed wet-blue looseness, as measured using a modified TM 174 technique, and crust looseness in 32 regions of 1,000 hides followed through commercial production. The main issue with all these techniques is that they cannot identify looseness in the raw material. Other studios in this project are looking at the chemical composition of base and tight hides, and follow a similar protocol to the one adopted in this study, where five regions of suspected loose hides are sampled and the remaining hide processed through to leather to identify whether it is actually base or not. Our observations, from investigating looseness in cattle hides identified at the slaughter plant through to crust leather, is that looseness cannot be readily observed from information gathered on animal condition, breed, age or gender, but does become more obvious once the hides are processed, and can be readily seen in the cross-section of processed hides. Note de contenu : - Technical aspects - Control measures - What was observed - Project outcomes En ligne : https://drive.google.com/file/d/1Le8yr_8z5bP70Pr65d4eVnV6eqRy1ldt/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=26903 [article]

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