A simple approach to leather process investigation part 3 - The development of the modified standard process for side leather / Ibrahim Elrufai abuelhassan in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 68 (Année 1984)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 68 (Année 1984) . - p. 125-138 Titre : A simple approach to leather process investigation part 3 - The development of the modified standard process for side leather Type de document : texte imprimé Auteurs : Ibrahim Elrufai abuelhassan, Auteur ; Alan Gordon Ward, Auteur ; S. Wolstenholme, Auteur Année de publication : 1984 Article en page(s) : p. 125-138 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux Essais (technologie) Procédés de fabrication Statistique Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : A standard process for the production of segments of chrome side leather, in a controlled manner, has been reported in T. Soc. Leather Technol. Chem., (1974), 58, 88. This process has been further developed to give a modified standard process in which the three main changes are (I) the use of whole sides in place of segments, (II) a drum liming procedure to replace the circulatory system employed previously for liming stationary segments, and (III) the transfer of the operation of splitting from the stage after liming to after chrome tanning. The course of development of the modified standard process is described, including details of consequential changes to deliming, pickling, tanning, basifying and neutralisation. It was also necessary to modify drying and conditioning, to enable whole sides to be handled. The properties of leather made by the modified process have been compared with those of standard process leathers. Although minor differences can be detected between the subjective properties (break, temper and grain quality) of leathers made by the two processes and also between a minority of the physical properties measured at corresponding locations on a side or segment, the similarities are sufficient to regard the new process as a near equivalent of the original process. Leathers made by the modified standard process on different occasions have highly reproducible properties and so the process is suitable for the study of the effect of variants in the leather-making operations on properties of the final leather. Note de contenu : - DEVELOPMENT OF THE MSP FOR WHOLE SIDES : Raw material - Siding - Brining, soaking and liming - Defining, pickling and tanning - Washing and neutralisation - Drying - Conditioning - Operation of the temperature and pH controlled drum - Machine operations - THE MODIFIED STANDARD PROCESS : Farm environment - Slaughterhouse procedure - Siding - Washing - Green fleshing - Brining - Brine pile - Soaking - Liming - Lime fleshing - Hair and scud removal - White liming - Washing - Deliming - Flushing - Bating - Flushing - Pickling and tannage - Chrome pile - Samming - Chrome splitting - Shaving - Washing - Neutralisation - Flushing - Dyeing - Flushing - Fatliquoring - Fatliquor pile - Samming and setting - Conditioning - Toggling - Storage - Process control - TEST METHOD DETAILS : Weight and area measurements - Sample squares for subjective and physical tests - Subjective and objective physical testing - Chemicsal tests - STATISTICAL ANALYSES AND EXPERIMENTAL PLANNING : The sign test for the paired case - Mann-Whitney test - Wilcoxon test - The Kruskall-Wallis test - PROCEDURES FOR PREPARING PACKS 1-4 : Pack 1. Check of SP operations - Pack 2. Introduction of drum liming and chrome splitting variants - Pack 3. Comparison of SP and MSP for whole sides - Pack 4 : The standard pack - EXPERIMENTAL RESULTS AND DISCUSSION : Reproducibility of the standard process for segments - Effect of the drum liming and chrome splitting variants (for segments) - The change to processing whole sides (pack 3) - The standard pack of MSP leather (pack 4) - Fig. 1 : Location of segment required for the standard process of laight and of the area of the 20 squares available for test samples from modified standard process leather, within the side used for the modified standard process - Fig. 2 : Squares within the area of the side used for test purposes, together with the arrangement and orientation of samples within the 12 squares usef for lastometer and Instron testing En ligne : https://drive.google.com/file/d/19qG8HFhp0_MD1IyHdLXox-NwG0mvfEX2/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34149 [article]

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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)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 68 (Année 1984) . - p. 159-177 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 10 En ligne : https://drive.google.com/file/d/1aacM-aFOH_q0yrFh5sCdNDtgDHjfz3ac/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34152 [article]

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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]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 69 (Année 1985) . - p. 1-16 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 : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=9392 [article]

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