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A simple approach to leather process investigation / P. Laight in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 60 (Année 1976)
[article]
Titre : A simple approach to leather process investigation : Part 1 - The introduction of variants in the liming, conditioning/staking and retannage/fatliquoring sub-processes Type de document : texte imprimé Auteurs : P. Laight, Auteur ; A. G. Ward, Auteur ; S. Wolstenholme, Auteur Année de publication : 1976 Article en page(s) : p. 1-11 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Chaulage
Conditionnement
Cuirs et peaux
Palissonnage
Produits de nourriture du cuir
RetannageIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : The process, already described in J. Soc. Leather Tech. Chem. (1974), 58, 88, for making standard segments of chrome tanned upper leather, has been modified by the introduction of selected variants. The subprocesses which have been varied are: (i) liming; (ii) staking and conditioning; (iii) retannage and fatliquoring. Control segments made by the unmodified standard process have been included as a part of each pack. In addition to measurements made during processing, the leathers produced have been assessed for their main mechanical properties, using both subjective and objective methods. The results show the exceptional reproducibility of the standard process itself and so enable the effects of the variants to be reliably assessed. The marked effect of increased duration of liming on subjective properties is not reflected in all the physical test results. The degree of staking employed (Mollisa) resulted in significant differences in subjective properties and in the stress/strain properties for low strains. The use of glutaraldehyde retannage and of a higher level of fatliquor produced significant differences in certain of the mechanical properties which were measured or assessed. Statistical analyses have been applied to the results of the factorial designs employed. Note de contenu : - The standard process and the leathers produced from it (Packs 1-5)
- The liming variant
- The conditioning/staking variant
- Table 1 : Water content as a percentage of dry fat free solids of pelt equilibriated with pH 3-72 buffer
- Table 2 : Variants introduced in the standard chrome side leather process
- Table 3 : Test results on completion of sub-process. Standard process II. Means, ranges and range of admissible variation (RAV) packs 4 and 5
- Table 4 : Mean values of test results for leathers front packs 1 and 2 (standard process I), pack 3 (standard process I with delays in brine and chrome pile), packs 4 and 5 (standard process II). For tensile specimens AI, M4, P4 perpendicular to backbone, M2 parallel to backbone
- Table 5 : Standard process H, packs 4 and 5. Mean values and the confidence limits for packs and sub-packs of two or four segments. (mean ± A gives the confident limits)
- Table 6 : Overall average values (packs 1 to 9) of 72 segments for weight and area during processing. Area values for sub-processes prior to drying are compared (as %) with the original area, for drying and after estimates are used, correcting for trimming of one end. Weights are related to the appropriate stages at which material
was removed (original, lime splitting, shaving, end trimming)
- Table 7 : Comparison of standard (mean packs 4, 5), and lime variant (mean packs 1, 2) leathers. student's "t" test (30 degrees of freedom). Calculated "t" values
- Table 8 : Comparison of standard (mean packs 4, 5) and lime variant (mean packs 1, 2) leathers. student's "t" test (30 degrees of freedom), calculated "t" values
- Table 9 : Conditioning/dtaking bariant. Allocation of degments 41-48 were collected from slaughter house one week before 49-56
- Table 10 : Overall treatment means for the Pairs of segments receiving identical conditioning/staking levels
- Table 11 : Two-way table of means for whole Segment subjective break values. Conditioning/staking variant
- Table 12 : Two-Way Table of means for stress at 10% extension (kg cm-2). Conditioning/staking variant
- Fig. 1 : Location of segment and test squares on the sideEn ligne : https://drive.google.com/file/d/1vj-qu2LdEERKvqdUQgzHaRr0le_y0-qW/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35263
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 60 (Année 1976) . - p. 1-11[article]Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 008596 - Périodique Archives Documentaires Exclu du prêt A simple approach to leather process investigation part 4 - The introduction of variants in the drying process / Ibrahim Elrufai abuelhassan in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 68 (Année 1984)
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Titre : A simple approach to leather process investigation part 4 - The introduction of variants in the drying process Type de document : texte imprimé Auteurs : Ibrahim Elrufai abuelhassan, Auteur ; A. G. Ward, Auteur ; S. Wolstenholme, Auteur Année de publication : 1984 Article en page(s) : p. 159-177 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux -- Séchage Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Details of the Modified Standard Process (MSP) for the controlled experimental production of side upper leather have been recorded in Part 3 (J. Soc. Leather Technol. Chem., 1984, 68, 125). The present part of the investigation examines the drying stage of the experimental procedure. MSP leather is dried, in the standard operation, using free hanging for the first drying and toggle drying for the second stage. The consequences of using different air temperatures and humidities for each of the two stages have been investigated. Leather produced using higher air temperatures for both drying stages was shown to differ from MSP leather in some properties. In particular, the leather has a tighter break but a firmer temper. Much more marked changes resulted from the use of paste drying, toggle drying or vacuum drying in place of free hanging for the first stage of drying. These first stage drying techniques were combined with the use of vacuum drying for the second stage. The leather dried initially either by paste drying or by toggle drying showed a coarser break, firmer temper, poorer grain quality and lower cutting value than the leathers dried initially by free hanging or vacuum drying. The differences were further shown in the physical tests, where the lastometer distension at grain crack was unacceptably low for the paste and toggle dried leathers and was reduced (to some degree) even for the vacuum dried leather, in comparison with free hanging. A limited study was made of the effect of the slicking direction, before paste drying, on the resulting leather properties. Only a small effect was noticed, the statistical significance of which could not be fully established. The study of how to improve the adversely affected properties of the paste dried leathers is described in Part 5, J. Soc. Leather Technol. Chem. (awaiting publication). Note de contenu : - INTRODUCTION : Variation of operating conditions using MSP drying procedures - Variation of the methods of drying - Variation of slicking direction in paste drying
- THE DRYING OPERATION : Free-hanging - Toggling, nailing - Paste-drying - Vacuum drying - Non-vacuum conduction drying
- EXPERIMENTAL METHODS : Samming-setting - Drying-free-hanging and toggling - Drying-Paste drying - Slicking out - Drying-Vacuum drying - Methods used for control during drying - Terst methods for the final leathers - Statistical techniques and experimental planning
- PROCEDURES FOR PREPARING PACKS 5-10 : Packs 5 and 6, drying conditions experiment 1 - Pack 7, drying conditions experiment 2 - Packs 8 and 9, drying methods experiment - Pack 10, slicking direction in paste drying experiment
- EXPERIMENTAL RESULTS AND DISCUSSION : Drying conditions, experiment 1, packs and 6 - Drying conditions, experiment 2, pack 7 - Packs 8 and 9, drying and methods experiments - General observations - Slicking direction in paste drying experiment, pack 10En ligne : https://drive.google.com/file/d/1aacM-aFOH_q0yrFh5sCdNDtgDHjfz3ac/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34152
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 68 (Année 1984) . - p. 159-177[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 007131 - Périodique Bibliothèque principale Documentaires Disponible A simple approach to leather process investigation part 5 - The correction of defects in paste dried leather by variants in retannage and fatliquoring / Ibrahim Elrufai abuelhassan in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 69 (Année 1985)
[article]
Titre : A simple approach to leather process investigation part 5 - The correction of defects in paste dried leather by variants in retannage and fatliquoring Type de document : texte imprimé Auteurs : Ibrahim Elrufai abuelhassan, Auteur ; A. G. Ward, Auteur ; S. Wolstenholme, Auteur Année de publication : 1985 Article en page(s) : p. 1-16 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : In part 4 (JSLTC, 1984, 68, 159) the effect of the main techniques of leather drying, free hanging, toggling, paste drying and vacuum drying, on the properties of side upper leather was studied. The leather was prepared by the Modified Standard Process (MSP) as described in part 3 (JSLCT, 1984, 68, 125), except for the drying variants. The leathers that had been dried by processes involving stretching (especially toggling and paste drying) were adversely affected as regards break and were also modified in temper. They showed substantially reduced distension to grain crack (lastometer) and elongation to rupture. The present investigation examined how far retannage and modified fatliquoring can restore the leather properties to the generally satisfactory standards of MSP leather itself. Preliminary experiments resulted in the selection of a combination retannage made up to Tanigan OS, Retingan R7 and mimosa extract. This retannage was used together with normal and enhanced levels of fatliquoring. The combined action of retanning and increased fatliquoring appeared, from the first trials, to be effective in improving the break characteristics and giving a softer leather. It failed, however, to achieve a satisfactory distension to grain crack in the lastometer teset. A trial was carried out on retannage and modified fatliquoring, using the full range of subjective and physical tests that were employed in previous parts of this work. The results fully confirmed the previous tentative conclusions that the subjective properties could be adjusted to match standard MSP leathers. Retannage had no significant effect on the grain brittleness arising from paste drying but the extra fatliquoring reduced somewhat the grain brittleness, in comparison with MSP leather, as assessed by the distension to grain crack (lastometer). The final sections of the paper describe studies on the weight, area and thickness of the sides, using data from the various packs studied in parts 3, 4 and 5. The paper concludes with a summary of findings collected from the entire investigation (Parts 1-5). Note de contenu : - The purpose and effects of retannage and fatliquoring.
- Experimental planning and procedures.
- Experimental results and discussion.
- The effect of processing on the weight, area and thickness of the experimental leathers.
- Termination of the investigation.En ligne : https://drive.google.com/file/d/1ihG9dhMlLSBny1OX8kazFIlRVx6xvnBA/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=9392
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 69 (Année 1985) . - p. 1-16[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 007132 - Périodique Bibliothèque principale Documentaires Disponible The mechanical properties of chrome tanned sheepskin. Variation of properties with position / Poulter Ward in JOURNAL OF THE SOCIETY OF LEATHER TRADES' CHEMISTS, Vol. 50, N° 4 (04/1966)
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Titre : The mechanical properties of chrome tanned sheepskin. Variation of properties with position Type de document : texte imprimé Auteurs : Poulter Ward, Auteur ; A. G. Ward, Auteur Année de publication : 1966 Article en page(s) : p. 130-138 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux -- Propriétés mécaniques
Cuirs et peaux de moutons
Essais dynamiques
Tannage au chrome
Traction (mécanique)Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The investigation of the variability of the mechanical properties of side and calf leather by Popplewell and Ward has been extended to chrome tanned sheepskin. The plastic set and stress for constant extension have been determined for strips from various positions on the tanned skin. The plastic set showed large variability between neighbouring samples. There was a tendency for strips from the belly region, tut parallel to the backbone, to give higher values of the set, on average, than elsewhere. The stress at constant extension varied systematically with position, the pattern resembling in main features that already reported for full chrome calf and side leather. The results have been related to observations of the fibre weave, as shown by the light microscope. Note de contenu : - EXPERIMENTAL : Tannage - Sampling - Conditioning - Testing
- EXPERIMENTAL RESULTS : Set - Stress for 10 % and 20 % extension - Instron tensile test measurement - Appearance of sections. Fibre structure
- Table 1 : Characteristics of samples for microscopie examination
- Table 2 : % Set for the regions of the skin
- Table 3 : Maximum and minimum stresses for 10% and 20% extension
- Table 4 : Mean values of 5 strips Temperature c. 20°c. Instron machinePermalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35680
in JOURNAL OF THE SOCIETY OF LEATHER TRADES' CHEMISTS > Vol. 50, N° 4 (04/1966) . - p. 130-138[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 007069 - Périodique Bibliothèque principale Documentaires Disponible