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Low strain characteristics of leather / R. G. Mitton in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 54, N° 2 (02/1970)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 54, N° 2 (02/1970) . - p. 44-53 Titre : Low strain characteristics of leather Type de document : texte imprimé Auteurs : R. G. Mitton, Auteur ; C. Price, Auteur Année de publication : 1970 Article en page(s) : p. 44-53 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Chaussures Cuir Cuirs et peaux de veaux Déformations (mécanique) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Upstone and ward have shown that, in the region of strains below 2% shoe upper leathers frequently have a low elastic modulus, which is much smaller than that for greater extensions. This is likely to be advantageous, because it permits a shoe to take up the shape of the foot without undue pressure, and yet resist deformations large enough to cause unsightliness and loss of shape. Experiments show that the shape of the stress/strain curve if frequently (and perhaps always) due to stresses in different layers of an unstrained leather, the grain layer being usually in tension when the leather if flat, and the corium and flesh in compression. Any leather strip which does not have this characteristic can be given it by suitable heat 'setting', such that an unstressed flat strip of the leather is left with its grain permanently in tension. Whether the 'steps' of the stress/strain curves are sufficiently large to be of practical importance is not clear. It is possible that heat setting during shoe making relaxes any differential stresses otherwise present, and that the steps consequently disappear in the made up shoe. Note de contenu : - Elastic and plastic changes of length - The shapes of extension/load curves - Extension/load curve for a poromeric - The mechanism of step formation - Table 1 : Observed and predicted values for two strips of chrome calf leather - Table 2 : Curvature and apparent extension of a composite strip En ligne : https://drive.google.com/file/d/11f3gGPrFKiu4dEpWP1xuX6v9abNQ5oSN/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36597 [article]

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The deterioration of pickled lambskins / P. A. Moffat in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 54, N° 2 (02/1970)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 54, N° 2 (02/1970) . - p. 54-76 Titre : The deterioration of pickled lambskins Type de document : texte imprimé Auteurs : P. A. Moffat, Auteur ; G. W. Vivian, Auteur Année de publication : 1970 Article en page(s) : p. 54-76 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux -- Détérioration Cuirs et peaux d'agneaux Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The influence of pickle liquor composition, as well as temperature and time of storage, on pickled sheep and calf skins have been thoroughly investigated by many workers. These faéctors have been referred to by Mitton and Bowes as the storage factors and their importance clearly demonstrated. Woodroff and Caughley showed the deleterious effect of high acid, approximately 1%, in the pickle liquor at the completion of the process on pelt quality during storage and recommended a 'low acid pickle' whereby the free acid is reduced from 1% to 0.3%. Most New Zealand productions now contain 0.5%-0.6% free acid. Advice from American tanners indicates that the productions have a variable shelf life which is independent of acid strength, so it is apparent that other factors in producing pickled pelts have an effect on their keeping qualities. The factors involved in the present study are outlined in the statistical design below. A hydration factor has been used in addition to the storage factors of previous workers, in view of the findings of Parr who shoed that pelt pieces pressed to reduce their original weight by 80% were in a sound condition after a storage period of 14 years. Four fellmongery processes have also been included. The storage factors are repeated in this study, since it is felt that there could be interactions between these and the fellmongery processes, as well as interactions with the new storage factor of degree of hydration. These interactions cannot be detected or quantitatively measured using the classical experimental method and for this purpose it is necessary to use factorial analysis. Note de contenu : - EXPERIMENTAL : Paint strength - Temperature of stacking - Liming - Deliming and bating - Pickling - Hydration - Temperature of storage - Time of storage - RESULTS : Visual - Chemical - Physical - - DISCUSSION : The relationship between chemical and physical data - Summary of the effects of processing and storage factors En ligne : https://drive.google.com/file/d/1kgENAJxw1On1JzGFmkioYxKYZJBWZyeU/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36598 [article]

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