Microscopic study of leather defects / A. L. Everett in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. LXI (Année 1966)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXI (Année 1966) . - p. 112-127 Titre : Microscopic study of leather defects : I. Veininess in glazed calfskin Type de document : texte imprimé Auteurs : A. L. Everett, Auteur ; H. J. Willard, Auteur ; J. Naghski, Auteur Année de publication : 1966 Article en page(s) : p. 112-127 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Cuirs et peaux -- Défauts Défaut de veine (cuir) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Prominent blood vessel pattern on the grain surface of leather is an esthetic defect which has long been troublesome and costly to the industry. In spite of numerous attempts to solve the problem, as summarized from the literature, the basic cause of the defect remains unknown. Inadequate curing and drastic processing were most frequently suspected, but so far there has been no conclusive proof. Therefore a continuing search for preventive measures would seem less practical than systematic testing of corrective treatments. Microscopic examination of cross-sections, improved by a suitable aqueous embedding technique, is shown to be helpful in guiding such a program. Studies of blood vessel distribution have established that they are typically arranged in three layers. The deepest and largest vessels, especially the arteries, are the principal offenders in this problem, but it is shown that their depth can be so variable that shaving is not a dependable solution. More significantly, there is almost always a large void space around the deep vessels in veiny leather but not in non-veiny samples, even from skins processed together in the same tannery pack. Thin skins are an especially difficult problem. The suggested approach for correction would be to fill there voids, either by plumping the fibers with a suitable retannage or by the use of impregnating materials. Cross-sections illustrating an experimental zirconium retannage indicate a definite reduction in void space and in consequent veininess. Likewise a resin treatment, being studied elsewhere, seems quite promising af ter preliminary trials. Note de contenu : - EXPERIMENTAL METHODS : Sectioning - Gelatin embedding - Microscopy - RESULTS AND DISCUSSION : Veiny vs. non-veiny skins - Veiny thin skins -Veniness without void space - Veniness reduced by retannage En ligne : https://drive.google.com/file/d/1kS5RRAvgc4pKf9T4XiHF_7NrLb0vAQTw/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37939 [article]

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Modified processing cockle defect in sheepskins / E. H. Bitcover in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. LXXV (Année 1980)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXXV (Année 1980) . - p. 49-53 Titre : Modified processing cockle defect in sheepskins Type de document : texte imprimé Auteurs : E. H. Bitcover, Auteur ; H. J. Willard, Auteur ; A. L. Everett, Auteur Année de publication : 1980 Article en page(s) : p. 49-53 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : - Dewooling - Reliming - Bating - Pickling Note de contenu : The cause of cockle defect in domestic sheepskins has been demonstrated. It is caused by keds (melophagus ovinus), which are blood-sucking parasites that live in the wool of sheep. The defect becomes apparent only after the wool is removed during processing. It appears as a scattering of dense nodules in the grain layer of sheepskins in a characteristic pattern of distribution. Affected sheepskin leathers can be seriously downgraded, depending on the severity of the defect. In addition, cockle reduces the physical strengh of both grain and suede leathers and increases their stiffness. Our earlier studies entailed special processing to expose the cockle nodules for easier counting. When subjected to certain process modifications, however, which were suggested by a cooperating tanner, sheepskins resulted that had lower apparent cockle counts and improved appearence. This paper describes certain process modifications which were found effective in attenuating some of the grosser defects in cockled sheepskins. En ligne : https://drive.google.com/file/d/1dzw6maIQs4fQ2BYG4WXDvuXXK0EXriw8/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=17726 [article]

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