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Advanced diagnostics and innovative solutions for leather defects : the problem of yellowing / Claudia Florio in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 103, N° 6 (11-12/2019)
[article]
inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 103, N° 6 (11-12/2019) . - p. 296-304
Titre : Advanced diagnostics and innovative solutions for leather defects : the problem of yellowing Type de document : texte imprimé Auteurs : Claudia Florio, Auteur ; Roberta Aveta, Auteur ; Gianluigi Calvanese, Auteur ; Biagio Naviglio, Auteur Année de publication : 2019 Article en page(s) : p. 296-304 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux -- Analyse
Cuirs et peaux -- Défauts
Jaunissement (défaut)Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Providing peculiar enhanced features to leather items is a factor of primary importance for the marketing of high-end articles; although tanning production is oriented to satisfy a wide market range, it is mainly in the `high end' and `premium luxury' categories that the quality properties of the material are more expressed, indeed. It is particularly on this market segment that the main current challenges have been focussed, according to the growing requirement of technological innovation, sustainability and product quality.
Light-coloured leathers, with particular reference to white items, belong to the category of materials designed especially for the luxury market. For this type of articles, the uniformity of colour and the agreeable appeal of the overall surface appearance are crucial requirements for the most international fashion and luxury brands.
One of the most common and undesirable defects of this type of article is the alteration of the colour, with particular reference to the localised or diffused effects of yellowing of the surface of the material. There are several causes able to contribute to the production of this type of defects, due to the complexity of the matrix and to the variability of traditional or innovative production processes used: from the intrinsic fragility, photosensitivity and thermo-sensitivity of the finishing polymers, to the chemical instability of some components of the finishing pigments, further the presence of photosensitive chemical additives, the migration of skin components or assembly components of the manufactured articles (fats, fillers, plasticisers, glues etc.), up to the indirect contribution of environmental and thermo-climatic factors able to affect negatively the performance of the material.
SSIP, which has always been involved in research and consulting activities for the leather industry with regards to defect monitoring, through this work, would offer an overview of all the main tools for advanced diagnostics (with particular reference to Scanning Electronic Microscopy and to chromatographic and spectroscopic methods) aimed to the identification of the causes of yellowing, beside to explore innovative solutions for the development of strategies for the resolution and/or minimisation of the problem of yellowing. The technical solutions will include innovative tanning processes, innovative finishing methods, and leather surface treatments carried out in order to provide a sensible attenuation of surface absorption of IR and UV-visible radiation.Note de contenu : - Technical and diagnostic approach
- Technical results
- Possible technical solutions
- Fig. 1 : The different main factors able to promote leather yellowing
- Fig. 2 : IR spectra overlap of the topcoat of defective and not defective samples
- Fig. 3 : Cross section and surface of a not defective calf leather and cross section and surface of a defective buffalo leather
- Fig. 4 : IR Spectrum of the glue found on the sample: spectroscopic profile compatible with a polyacrylate
- Fig. 5 : Gas-chromatographic profile of the organic extract of the defective sample (leather for footwear)
- Fig. 6 : Overlap of the gas-chromatographic profiles of the organic extract of the defective and not defective parts of the sample (leather for automotive)
- Fig. 7 : 2-Octyl-2H-isothiazol-3-one
- Table 1 : Gas-chromatographic determination of the volatile substances in the non-defective sample
- Table 2 : Gas-chromatographic determination of the volatile substances in the defective sampleEn ligne : https://drive.google.com/file/d/1nLKxh25oQc7eYZjHyti_fPnv9AefpJdf/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=33206 [article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 21314 - Périodique Bibliothèque principale Documentaires Disponible Alkylated phenolic antioxidants for paints / V. C. Malshe in SURFACE COATINGS INTERNATIONAL. PART B : COATINGS TRANSACTIONS, Vol. 88, B2 (05/2005)
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inSURFACE COATINGS INTERNATIONAL. PART B : COATINGS TRANSACTIONS > Vol. 88, B2 (05/2005) . - p. 145-148
Titre : Alkylated phenolic antioxidants for paints Type de document : texte imprimé Auteurs : V. C. Malshe, Auteur ; S. Elango, Auteur Année de publication : 2005 Article en page(s) : p. 145-148 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Alkylation
Antioxydants
Blanc (couleur)
Brillance (optique)
Evaluation
Formaldéhyde
Jaunissement (défaut)
Phénols
Résistance au jaunissement
Revêtements -- Additifs:Peinture -- AdditifsIndex. décimale : 667.9 Revêtements et enduits Résumé : Polymeric antioxidants based on p-cumyl phenol formaldehyde resin (PCPF), p-nonyl phenol formaldehyde (PNPF) and p-octyl phenol formaldehyde (POPF) were prepared by condensation reaction of respective phenols with formaldehyde in presence of an acid catalyst. The reactions were monitored by TLC and the melting point of the products was determined by open capillary method. Stabilising the action of PCPF, PNPF for protecting paint against thermal oxidation was tested using a QUV weatherometer. The effect of exposure on the properties of paints such as gloss, whiteness and yellowness were evaluated. Results show that paints containing these new polymeric antioxidants possess better stabilising effects against photo-oxidation than those employed in standard paints available in the market. Note de contenu : - EXPERIMENTAL : Materials - Synthesis
- RESULTS AND DISCUSSION : Evaluation of prepared compounds as antioxidants
- GLOSS : Effect of antioxidants (at 10, 100, 200 and 300 ppm) on gloss - Whiteness and yellownes - Effect of antioxidants (at 10, 100, 200 and 300 ppm) on whiteness - Effet of antioxidants (at 10, 100, 200 and 300 ppm) on yellownessDOI : 10.1007/BF02699547 En ligne : https://link.springer.com/content/pdf/10.1007/BF02699547.pdf Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5429 [article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 001966 - Périodique Bibliothèque principale Documentaires Disponible 002343 - Périodique Bibliothèque principale Documentaires Disponible Conservation concerns for acrylic emulsion paint coatings / M. Veeramani in PAINTINDIA, Vol. LXXII, N° 5 (05/2022)
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inPAINTINDIA > Vol. LXXII, N° 5 (05/2022) . - p. 92-94
Titre : Conservation concerns for acrylic emulsion paint coatings Type de document : texte imprimé Auteurs : M. Veeramani, Auteur Année de publication : 2022 Article en page(s) : p. 92-94 Langues : Anglais (eng) Catégories : Décoloration
Formation de film
Jaunissement (défaut)
Oxydation
Pigments
Polyacryliques
Porosité
Réticulation (polymérisation)
Revêtements -- Détérioration:Peinture -- Détérioration
Revêtements en phase aqueuse:Peinture en phase aqueuse
Revêtements organiquesIndex. décimale : 667.6 Peintures Résumé : The basic process of film coalescence has been described frequently in the conservation and paint industry literature, though technologists acknowledge the over-simplification of this model and the need for further research. Acrylic emulsions are composed of particles of amorphous polymer suspended in water. The two-phased system is held in suspension by surfactants and/or other surface stabilisers. During drying, water evaporates to draw the spherical polymer particles Gloser, which then meld together to form a 'honeycomb' network. A coalescing-solvent additive ensures that the polymer particles remain malleable during — and after— this process, to produce more complete compaction, even after the water has evaporated. Eventually, the boundaries between particles become barely detectable and the film is considered continuous. However, it has been shown that pores or micro-voids are often left within the film, readily seen with light microscopy and SEM. minimum film formation temperature (MFT), modulus of elasticity and viscosity of the resin, as well as the function of additives such as coalescing agents. Paints left to dry slightly below their Tg and MFT wi II result in films of h igher porosity. A paint drying significantly below its Tg will form a loose, powdery layer.
Note de contenu : - Paint properties - Film formation
- Film porosity and pin-holes
- Haziness
- Thermo plasticity
- Properties of additives
- Ageing properties : Yellowing/discoloration
- Cross-linking and oxidation
- Effect of pigments
- Affinity for dirt pick-up
- Sensitivity to solvent
- Sensitivity to waterEn ligne : https://drive.google.com/file/d/1Zo1kAgDw2np8uJc2u-Jrs-MIHqjfEewS/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37803 [article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 23454 - Périodique Bibliothèque principale Documentaires Disponible How to achieve faster dry times and more with high-performance catalysts in low-VOC alkyd coatings / Allison Abbey in COATINGS TECH, Vol. 19, N° 1 (01/2022)
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inCOATINGS TECH > Vol. 19, N° 1 (01/2022) . - p. 34-43
Titre : How to achieve faster dry times and more with high-performance catalysts in low-VOC alkyd coatings Type de document : texte imprimé Auteurs : Allison Abbey, Auteur ; Loulou Rozek, Auteur ; Maxwell Shumba, Auteur Année de publication : 2022 Article en page(s) : p. 34-43 Langues : Américain (ame) Catégories : Adhésion
Catalyseurs
Dureté (matériaux)
Formulation (Génie chimique)
Jaunissement (défaut)
Polyalkydes
Résistance à l'humidité:Résistance à l'eau
Revêtement -- Séchage
Revêtement en phase solvant
Revêtements en phase aqueuse
Revêtements organiquesIndex. décimale : 667.9 Revêtements et enduits Résumé : The alkyd coating market continues to face increasing challenges as government bodies and environmental agencies establish new volatile organic content (VOC) and regulatory restrictions. In many cases, reformulation is necessary to meet ow-VOC requirements, which may cause adverse effects in the final coating, such as slow dry times, increasingly complex formulations, and poor coating performance. Formulators can overcome such performance obstacles in sustainable coatings by using the proper high-performance catalyst (HPC). This unique technology can meet VOC requirements, outperform standard metal carboxylates across multiple resin platforms, and may eliminate the need for complex drier packages. Note de contenu : - EXPERIMENTAL PRACTICES
- HOW TO FORMULATE WITH HPCS : Sample preparation - Dry-time evaluations - Hardness - Yellowing - Loss of dry (LOD) - Skinning - Adhesion - Water resistance
- RESULTS AND DISCUSSION : High-solids solventborne alkyd case study - Water-reducible alkyd case study - Waterborne alkyd case studyEn ligne : https://drive.google.com/file/d/1995MAOGS83aC3OuULSvhKoZLSqvp67uX/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37170 [article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 23290 - Périodique Bibliothèque principale Documentaires Disponible Leather ageing and hexavalent chromium formation as a function of the fatliquoring agent. Part I : chrome tanned leathers / Ramón Palop in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 92, N° 5 (09-10/2008)
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inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 92, N° 5 (09-10/2008) . - p. 200-204
Titre : Leather ageing and hexavalent chromium formation as a function of the fatliquoring agent. Part I : chrome tanned leathers Type de document : texte imprimé Auteurs : Ramón Palop, Auteur ; Joan Parareda, Auteur ; Olga Ballùs, Auteur ; Agusti Marsal, Auteur Année de publication : 2008 Article en page(s) : p. 200-204 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuir -- Effet du rayonnement ultraviolet
Cuir -- Teneur en chrome hexavalent
Cuirs et peaux -- Détérioration
Cuirs et peaux -- Effets de la température
Essais (technologie)
Jaunissement (défaut)
Produits de nourriture du cuir
Tannage au chromeIndex. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The aim of this work was to evaluate the influence of eighteen different types of fatliquoring agents on leather ageing.
Temperature and ultraviolet light tests were conducted separately. The existence of a direct relationship between leather yellowing, diminution of shrinkage temperature, autoflammability and odour was confirmed.
There was also a non-linear relationship between the above parameters and the iodine index of the fatliquoring agents.
Hexavalent chromium was not formed when temperature tests were applied on neutralised and fatliquored leathers. The possible physicochemical mechanisms for this phenomenon are discussed.
The temperature test exerted greater influence than the ultraviolet light tests on the aforementioned parameters.Note de contenu : - AIM OF THE WORK
- EXPERIMENTAL PROCEDURES : Materials and methods - Evaluation of the treated samples
- RESULTS AND DISCUSSION : Effect of temperature - Relationship between iodine number an the parameter evaluated
- Table 1 : Process details
- Table 2 : Fatliquoring agents used with their iodine index
- Fig. 1 : Influence of temperature on yellowing
- Fig. 2 : Influence of temperature on shrinkage temperature
- Fig. 3 : Yellowing and detanning mechanisms
- Fig. 4 : Plot of shrinkage temperature versus quantity of fixed chromium
- Fig. 5 : Influence of temperature on denaturing temperature
- Fig. 6 : Influence of temperature on odour
- Fig. 7 : Influence of temperature on surface area variation
- Fig. 8 : Influence of ultraviolet light on yellowing
- Fig. 9 : Influence of ultraviolet light on shrinkage temperaturePermalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35251 [article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 21781 - Périodique Bibliothèque principale Documentaires Disponible Substituted benzotriazole as UV absorber for paints / V. C. Malshe in SURFACE COATINGS INTERNATIONAL. PART B : COATINGS TRANSACTIONS, Vol. 87, B4 (12/2004)
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PermalinkThe effect of glucose oxidase enzyme on wool fibres / Berrak Buket Avci in COLORATION TECHNOLOGY, Vol. 139, N° 2 (04/2023)
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