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Hide, skin and leather defects : a guide to their microscopy / Mary Dempsey / Palmerston North [Nouvelle Zélande] : New Zealand Leather and Shoe Research Association (1984)
Titre : Hide, skin and leather defects : a guide to their microscopy Type de document : texte imprimé Auteurs : Mary Dempsey, Auteur Editeur : Palmerston North [Nouvelle Zélande] : New Zealand Leather and Shoe Research Association Année de publication : 1984 Importance : 105 p. Présentation : ill. Format : 31 cm Note générale : Index - Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux -- Défauts Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Preservation - Heat damage - Alkali damage - machine related defects - Miscellaneous blemishes - Some physical defects - Skin structural features - Diseases - Some healed conditions - Photosensitivity - Miscellaneous. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=1689 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 1425 675 DEM Monographie Bibliothèque principale Documentaires Disponible Lime speck / Mary Dempsey in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 58 (Année 1974)
[article]
Titre : Lime speck Type de document : texte imprimé Auteurs : Mary Dempsey, Auteur ; I. R. Hughes, Auteur Année de publication : 1974 Article en page(s) : p. 12-15 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Chaulage
Chaux
Cuirs et peaux
TachesIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : Lime speck, which is first clearly recognised in the pickled pelt as white spots or areas, was experimentally shown to originate in the painted skin According to X-ray analysis and microscopical examination the defect is due to gypsum (CaS042H20) within the grain layer. While painted skin piled for one day before pulling remained clear, skin piled for three days or four days developed speck. The effect was aggravated at raised temperature and by drying, though skin which was still moist at the end of piling could also become speckled. X-ray analysis of limed, bated, and pickled pelts showed that calcium carbonate (in the form of calcite) was the precursor in the limed pelt of speck in the pickled. Nevertheless, calcium carbonate present as calcite in the lime used for the paint did not affect the incidence of speck. It appears that calcite as precursor is formed in situ and, so long as sufficient calcium ions and carbon dioxide are available, will form if, during piling, water is extracted from the system by the collagen fibres (tending to plump under the alkaline conditions) or by the fleece (competing with the pelt for water) or by evaporative drying.
The small amount of calcite found in the clear limed pelt appeared to have been directly transformed into gypsum in the clear pickled pelt, but an intermediate, vaterite—another form of calcium carbonate—occurred in the affected bated pelt: its role in the transformation to gypsum is not understood.
The practical implications of the work are: duration of piling should be kept short, skins should be piled cool and in a cool place, conditions encouraging skins to heat in pile and conditions that could allow evaporative drying to start should be avoided.Note de contenu : - EXPERIMENT I : The effect of drying and duration in pile - X-ray diffusion analysis - Results
- EXPERIMENT II : The effect of composition of the lime used, duration and temperature in pile, and position of the pelt in pile - Results
- Table 1 : Composition of lime (Exp. II)
- Table 2 : Effect on duration and temperature on incidence of speck
- Fig. 1 : Section through grain of speckled pelt, where the spots were discrete. Photographed between partially
- Fig. 2 : Diagram to show the piling of pieces in Experiment I, B and CEn ligne : https://drive.google.com/file/d/14h849ao9XmG_6ZyJI6mHyymq23GVqeb4/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35481
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 58 (Année 1974) . - p. 12-15[article]Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 008594 - Périodique Archives Documentaires Exclu du prêt Some investigations into methods of unhairing - I. Lime-sulphide processing / R. S. Andrews in JOURNAL OF THE SOCIETY OF LEATHER TRADES' CHEMISTS, Vol. 50, N° 6 (06/1966)
[article]
Titre : Some investigations into methods of unhairing - I. Lime-sulphide processing Type de document : texte imprimé Auteurs : R. S. Andrews, Auteur ; Mary Dempsey, Auteur Année de publication : 1966 Article en page(s) : p. 218-245 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Chaux Sulfurée
Cuirs et peaux de moutons
Epilage
Hydroxyde de sodiumL'hydroxyde de sodium, appelé également soude caustique7, est un corps chimique composé minéral de formule chimique NaOH, qui est à température ambiante un solide ionique. Fusible vers 318 °C, il se présente généralement sous forme de pastilles, de paillettes ou de billes blanches ou d'aspect translucide, corrosives et très hygroscopiques. Il est très soluble dans l'eau et légèrement soluble dans l'éthanol.
La solution d'hydroxyde de sodium, souvent appelée soude, est une solution aqueuse transparente. Concentrée, elle est corrosive et souvent appelée lessive de soude.
Les propriétés chimiques de l'hydroxyde de sodium sont surtout liées à l'ion hydroxyde HO- qui est une base forte. En outre, l'hydroxyde de sodium réagit avec le dioxyde de carbone (CO2) de l'air et se carbonate.
La solubilité de la soude caustique dans l'eau augmente avec la température, à pression constante ou ambiante.
Sulfure de sodiumIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : Experimental lime-sulphide treatment has been assessed from the fibre structure of the pickled pelt (after fixing it in formalin + salt) compared with that from "normal" processing : soaking, liming, deliming, bating and pickling, or soaking, painting, liming, deliming, bating and pickling. Ease of unhairing and removal of epidermis have also been considered. The investigation included experiments on the influence of temperature, composition of the lime liquor, alkaline baths subsequent to painting, duration of piling in paint and composition of tir ; paint.
Unhairing and epidermis removal are shown to be two different process.cs under the conditions of lime-sulphide treatment, in which unhairing is only removal of hair shaft leaving the root and a short length of shaft within the grain layer. The paint, penetrating from the flesh, appeared to have passed the root, both bulb and club types, as well as newly initiated hair papillae, and begun attack on the hair at the level of the sebaceous gland. Breakdown of the hair shaft can extend both inwards towards the root and outwards along the free hair shaft: the hair cuticle was more resistant than the internai structure. Readily visible damage to the free hair shaft was caused by high amount of water in the paint or high amount of sulphide in the presence of high amount of water.
The "normal" paint used in the experiment was approximately 0-8 g Na2S + 5 g lime + 7 g water to 100 g pelt, and at the end of piling for 24 hours belly unhaired readily but butt did not. With this paint, increased time in pile did not improve the degree of unhairing, nor did raised temperature which did however, improve the removal of epidermis. Liming after painting completed unhairing and removal of epidermis, but it seems possible that caustic soda after painting might have an adverse effect on unhairing if this has not at least begun at the end of piling. Caustic soda in the paint did not improve unhairing, but where the hair was loose the removal of epidermis was seen to be easier than in its absence.
Painting opened up fibre bundles but did not open up the weave pattern, in contrast to liming or to painting followed by liming, after which fuller fibre bundles and less compactly interweaving pattern occurred. Increasing sodium sulphide in the paint increased splitting up and, especially when the pelt was piled at raised temperature, led to separation and a damaged appearance of the fibre structure. Caustic soda in a lime-sulphide paint, increased the fullness of the fibre bundles. Raised temperature had a marked effect in opening up the structure, particularly of the belly, which, at room temperature, usually appeared little opened up.
Immersion and movement in lime liquor containing a low concentration of sodium sulphide satisfactorily unhaired the pelt, and, especially at raised temperature, opened up the fibre structure.Note de contenu : - Materials and methods
- Alkaline treatment subsequent to painting : Unhairing
- Experiments on flesh side painting : Duration of piling in paint - Composition of the Paint - Microscopical observations
- Composition of the lime liquor : Unhairing and Epidermis Removal - Fibre structure
- Table 1 : Experimental treatments and scores for hair removal
- Table 2 : Flesh-painting experiments
- Table 3 : Scores for hair removal after piling in paint
- Table 4 : Composition of the paint : Amount of sodium sulphide or caustic soda scores for unhairing and removal of epidermis
- Table 5 : Hair and epidermis : Scores
- Table 6 and 7 : Hair and epidermis removalPermalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35679
in JOURNAL OF THE SOCIETY OF LEATHER TRADES' CHEMISTS > Vol. 50, N° 6 (06/1966) . - p. 218-245[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 007071 - Périodique Bibliothèque principale Documentaires Disponible The rapid fellmongering of New Zealand skins / Mary Dempsey in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 61 et 62 (Années 1977 et 1978)
[article]
Titre : The rapid fellmongering of New Zealand skins Type de document : texte imprimé Auteurs : Mary Dempsey, Auteur ; J. Haarer, Auteur ; I. R. Hughes, Auteur ; G. W. Vivian, Auteur Année de publication : 1978 Article en page(s) : p. 108-113 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Chaulage
DélainageIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : In experiments on rapid processing of pelts with paints made of sodium sulphide and caustic soda thickened with lime, good pull was achieved after 2 h with a paint at 2000 mgEq NaOH/1 containing not less than 6° Bé sodium sulphide (4 % Na2S). The temperature in pile was controlled by the temperature of the pelt at painting. Raising the temperature in pile (18° was compared to 22°c) favoured wool loosening but unduly loosened the "scud" (epidermal residue left over the pelt) especially if the paint contained a high amount of caustic soda. After a 2 h wool pull and liming at cool temperatures (16° was compared with 26°c falling to 23° overnight) the pelt was more mottled than the normal current production. Liming at 32°c and pH 12.5 reduced mottle to a level satisfactory for nappa leathei and gave fuller feeling leather, but one of three cooperating tanners found some dull grain in leather from 2 h pull and warm liming. Liming at 32°c may be dangerously warm for works conditions: temperature not higher than 28 ° is recommended. The relation between the blood vessels in the skin and plumping on the one hand and, on the other, increased temperature and opening up of the fibre structure explains the development of mottle and its avoidance by warm liming. Note de contenu : - Preliminary tests
- Experiment I
- Experiment II
- Results : Works reports - Laboratory report
- Experiment III
- Table 1 : The effect of alkalinity
- Table 2 : Pulling (Experiment I)
- Table 3 : The lime liquors (Experiment I)
- Table 4 : Analyses of paint (experiment II) (mgEq NaOH/I)
- Table 5 : Assessment of sample plets (experiment II)
- Fig. 1 : Blood vessels and mottle. The collagen fibres are closely woven round the blood vessel and less compactly interwoven elsewhere. The diagram roughly indicates the flow of the fibres in the weave pattern of the pelt
- Fig. 2 : Milk lamb pelt of normal production. The section has not quite gone along the blood vessel and the hatching in the diagram indicates its consequently vaguely pictured path through the pelt in the photomicrograph. Some wool roots (WR) and fat globules (F) are also indicated
- Fig. 3 : Milk lamb of Quikpul production. The section went through some length of the blond vessel shown in the micrograph. Its direction through the pelt is indicated by arrows. The fibre structure is considerably opened up. The wall of the vessel appears relaxedEn ligne : https://drive.google.com/file/d/19saAvF3xOGKIRdhICh8Bj6ioEpyBNrQg/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35224
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 61 et 62 (Années 1977 et 1978) . - p. 108-113[article]Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 008597 - Périodique Archives Documentaires Exclu du prêt The rapid fellmongering of New Zealand skins / Mary Dempsey in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 62, N° 5 (09-10/1978)
[article]
Titre : The rapid fellmongering of New Zealand skins Type de document : texte imprimé Auteurs : Mary Dempsey, Auteur ; J. Haarer, Auteur ; I. R. Hughes, Auteur ; G. W. Vivian, Auteur Année de publication : 1978 Article en page(s) : p. 108-113 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux
DéchaulageOpération consistant à débarrasser les peaux de la chaux et des substances alcalines qui leur ont été appliquées au pelanage.
DélainageIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : In experiments on rapid processing of pelts with paints made of sodium sulphide and caustic soda thickened with lime, good pull was achieved after 2 h with a paint at 2000 mgEq NaOH/1 containing not less than 6° Bé sodium sulphide (4 % Na2S). The temperature in pile was controlled by the temperature of the pelt at painting. Raising the temperature in pile (18° was compared to 22°c) favoured wool loosening but unduly loosened the "scud" (epidermal residue left over the pelt) especially if the paint contained a high amount of caustic soda. After a 2 h wool pull and liming at cool temperatures (16° was compared with 26°c falling to 23° overnight) the pelt was more mottled than the normal current production. Liming at 32°c and pH 12.5 reduced mottle to a level satisfactory for nappa leathei and gave fuller feeling leather, but one of three cooperating tanners found some dull grain in leather from 2 h pull and warm liming. Liming at 32°c may be dangerously warm for works conditions: temperature not higher than 28 ° is recommended. The relation between the blood vessels in the skin and plumping on the one hand and, on the other, increased temperature and opening up of the fibre structure explains the development of mottle and its avoidance by warm liming. Note de contenu : - Preliminary tests
- Experiment I
- Experiment II
- Results : Works reports - Laboratory report
- Experiment III
- Table 1 : The effect of alkalinity
- Table 2 : Pulling (Experiment I)
- Table 3 : The lime liquors (Experiment I)
- Table 4 : Analyses of paint (experiment II) (mgEq NaOH/I)
- Table 5 : Assessment of sample plets (experiment II)
- Fig. 1 : Blood vessels and mottle. The collagen fibres are closely woven round the blood vessel and less compactly interwoven elsewhere. The diagram roughly indicates the flow of the fibres in the weave pattern of the pelt
- Fig. 2 : Milk lamb pelt of normal production. The section has not quite gone along the blood vessel and the hatching in the diagram indicates its consequently vaguely pictured path through the pelt in the photomicrograph. Some wool roots (WR) and fat globules (F) are also indicated
- Fig. 3 : Milk lamb of Quikpul production. The section went through some length of the blond vessel shown in the micrograph. Its direction through the pelt is indicated by arrows. The fibre structure is considerably opened up. The wall of the vessel appears relaxedEn ligne : https://drive.google.com/file/d/1rcZvhmfBGTtkE-SxBu4n76rmlQ-z33U1/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=40492
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 62, N° 5 (09-10/1978) . - p. 108-113[article]