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Computations of coating windows for reverse roll coating of liquid films in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 17, N° 4 (07/2020)
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Titre : Computations of coating windows for reverse roll coating of liquid films Type de document : texte imprimé Année de publication : 2020 Article en page(s) : p. 897-910 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Traitement rouleau à rouleau Tags : 'Revêtement rouleau à rouleau' au inversé' 'Fenêtre de revêtement' 'Stabilité du Index. décimale : 667.9 Revêtements et enduits Résumé : This paper focuses on the flow stability of reverse roll coating flows employed in practical applications to coat thin liquid films on substrates of different materials. Other coating methods are available and various computer programs are purported to predict (for each corresponding method) the set of parameters that permit stable coating conditions. The application of these programs yields so-called coating windows for each particular coating setup. Knowing these coating windows permits coating methods to be applied with preknowledge of the sets of parameters for stable coatings. For reverse roll coating, computer codes for predicting coating windows are scarce or even nonexistent, which was the reason for the present work on the analytical considerations described in this paper. The results obtained formed the basis for a reverse roll coating computer program and its applications. The program is described, and computational results are provided. These are compared with experimental data available in the literature. Good agreement was obtained for high capillary number flows, but there were discrepancies between experimental and computational results for lower capillary numbers. The experimental results for low capillary number flows also appeared less reliable, which triggered the present experimental work. Some experimental results are given for low capillary numbers and these results are also compared with corresponding numerical data. It is suggested that a test section should be built consisting of two rollers and one slot die to study experimentally the stability regions of reverse roll coating flows in a rigorous manner. Note de contenu : - Theoretical background and essential equations
- Program to predict coating window suite
- Computations and results : Parameter study - Validation against experimental data
- Present experiments and first resultsDOI : https://doi.org/10.1007/s11998-020-00328-1 En ligne : https://link.springer.com/content/pdf/10.1007/s11998-020-00328-1.pdf Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34379
in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 17, N° 4 (07/2020) . - p. 897-910[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 21864 - Périodique Bibliothèque principale Documentaires Disponible Comparison of methods to assess pigment dispersion / Sang T. Van in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 73, N° 923 (12/2001)
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Titre : Comparison of methods to assess pigment dispersion Type de document : texte imprimé Auteurs : Sang T. Van, Auteur ; Bhaskar V. Velamakanni, Auteur ; Ronald R. Adkins, Auteur Année de publication : 2001 Article en page(s) : p. 61-70 Note générale : Bibliogr. Langues : Américain (ame) Tags : Etude expérimentale Distribution dimension particule Propriété rhéologique Opacité Contraste Brillant optique Broyeur rouleau comparative Méthode mesure Dispersion Pigment Broyage Fabrication Encre Index. décimale : 667.9 Revêtements et enduits Résumé : Two inks made with different red pigments were evaluated by common methods to assess the degree of pigment dispersion. One pigment is more difficult to disperse than the other in the vehicle used. The five methods that could detect changes in dispersion with each pass over a three-roll mill were a light scattering particle size distribution analyzer, a NPIRI fineness of grind gauge, gloss, contrast ratio measurements, and rheology. The gloss and contrast ratio measurements could detect changes with each pass over a three-roll mill only with a significant reduction in pigment particle size. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5772
in JOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 73, N° 923 (12/2001) . - p. 61-70[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 001231 - Périodique Bibliothèque principale Documentaires Disponible Occupational exposure to airborne isocyanates during brush/roller application of 2-pack polyurethane paints in a tropical climate / G. DeNola in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 7, N° 2 (03/2010)
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Titre : Occupational exposure to airborne isocyanates during brush/roller application of 2-pack polyurethane paints in a tropical climate Type de document : texte imprimé Auteurs : G. DeNola, Auteur ; J. Kibby, Auteur ; P. J. Hanhela, Auteur ; T. H. Gan, Auteur ; W. Mazurek, Auteur Année de publication : 2010 Article en page(s) : p. 201-208 Note générale : Bibliogr. Langues : Américain (ame) Tags : 'Peinture polyuréthane' Isocyanates Brosse 'Prélèvement air' 'Exposition professionnelle' Rouleau Analyse Index. décimale : 667.9 Revêtements et enduits Résumé : Shipboard and laboratory trials were conducted to determine airborne occupational exposure to isocyanates by brush/roller application of 2-pack polyurethane paints. Airborne concentrations in the breathing zones of the operators were found to be <0.1 µg/m3 during the paint application to a vessel deck, in a tropical climate, in the open air. Similarly, brush/roller application of the paints in an enclosed space generated airborne isocyanate concentrations <3 µg/m3. The dust generated during light sanding of the polyurethane paint, 24 h after curing, did not show detectable levels of isocyanates. DOI : 10.1007/s11998-009-9179-z En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-009-9179-z.pdf Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=9066
in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 7, N° 2 (03/2010) . - p. 201-208[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 012083 - Périodique Bibliothèque principale Documentaires Disponible Pigment dispersion : III / Zeno W. Wicks in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 73, N° 923 (12/2001)
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Titre : Pigment dispersion : III Type de document : texte imprimé Auteurs : Zeno W. Wicks, Auteur ; S. Peter Pappas, Auteur ; Frank N. Jones, Auteur Année de publication : 2001 Article en page(s) : p. 77-83 Note générale : Bibliogr. Langues : Américain (ame) Tags : Méthode mesure Broyeur rouleau Appareil agité Broyage humide Sable Corps broyant bille boulet disque Equipement Dispersion Pigment Fabrication Peinture Index. décimale : 667.9 Revêtements et enduits Résumé : Pigments are manufactured with the particle size distribution that gives the best compromise of properties, but the particles often become cemented together into aggregates during processing. Breaking these aggregates and forming stable dispersions of optimally sized pigment particles is a critical process in the manufacture of coatings. Making dispersions involves three aspects: (1) wetting, (2) separation, and (3) stabilization. Most authors agree that there are three aspects to dispersion but different terms are used, sometimes with conflicting meanings. Be careful reading papers to know how an author is using the terms. Because of effects of the high surface tension and polarity of water, consideration of pigment dispersion is separated in three sections. The first section (JCT, October 2001, page 145), dispersion in organic media, usually solutions of resins in organic solvent, was discussed. Dispersion in aqueous media is treated in the Formulation of Mill Bases section in this issue. The third section covers the use of Dispersion Equipment and Processes as well as the Evaluation of the Degree of Dispersion. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5775
in JOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 73, N° 923 (12/2001) . - p. 77-83[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 001231 - Périodique Bibliothèque principale Documentaires Disponible Rheology and flow of paints in roll coating processes / Olivier Cohu in SURFACE COATINGS INTERNATIONAL, Vol. 80, N° 3 (03/1997)
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Titre : Rheology and flow of paints in roll coating processes Type de document : texte imprimé Auteurs : Olivier Cohu, Auteur ; A. Magnin, Auteur Année de publication : 1997 Article en page(s) : p. 102-107 Note générale : Bibliogr. Langues : Anglais (eng) Tags : Peinturage 'Coil coating' Rouleau Ecoulement 'Propriété rhéologique' Peinture Etalement Feuil Epaisseur Index. décimale : 667.9 Revêtements et enduits Résumé : The paints used in the coil-coating/roll-coating process often have a rheological behaviour of the thixotropic yieldstress type. This may be necessary in order to prevent the pigments from settling during storage. However, it has been shown that the structures responsible for this behaviour should be sufficiently fragile to be destroyed very quickly as the paint passes between two counter-rotating rolls, in spite of the brief period of time the fluid is subjected to stresses during this flow. It therefore follows that modelling the process with a view to predicting the thickness of the final coating may be based on a determination of the viscosity of the paints in a steady flow regime at 104 s−1, a result which was confirmed by coating experiments.
In contrast, the ability of a paint to level the defects that are inevitably generated on the liquid film is connected with its thixotropic properties. In order to obtain representative data, they must be measured during unsteady flow with a low rate of shear, following intense pre shearing. It has been shown that the kinetics of paint structure recovery, or recovery of viscosity, is of decisive importance. If this occurs too rapidly, a significant yield stress appears before the film is completely levelled, thus fixing the residual defects. The thixotropic properties, required to prevent sedimentation from occurring, must therefore be characterised by a sufficiently slow structure recovery time.Note de contenu : - Analysis of the oil-coating processNALYSYS OF THE OIL-COATING PROCESS
- STEADY-STATE RHEOLOGY OF PAINTS
- BEHAVIOUR OF PAINTS FLOWING BETWEEN TWO COUNTER-ROTATING ROLLS
- APPLICATION TO THE PREDICTION OF COATING THICKNESS
- RHEOLOGY OF PAINTS AND FILM LEVELLINGPermalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=17152
in SURFACE COATINGS INTERNATIONAL > Vol. 80, N° 3 (03/1997) . - p. 102-107[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 006580 - Périodique Bibliothèque principale Documentaires Disponible