Achieving class a appearance on fiber-reinforced substrates / Donald H. Campbell in COATINGS TECH, Vol. 18, N° 6 (06/2021)  

[article]  inCOATINGS TECH > Vol. 18, N° 6 (06/2021) . - p. 32-40 Titre : Achieving class a appearance on fiber-reinforced substrates : Achieving Class A appearance over fiber-reinforced substrates can be challenging. Learn about solutions and the evolving measurements used to characterize topcoated surface appearance Type de document : texte imprimé Auteurs : Donald H. Campbell, Auteur ; G. Singh, Auteur ; Cindy Peters, Auteur ; Jacob Dumbleton, Auteur Année de publication : 2021 Article en page(s) : p. 32-40 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Automobiles -- Revêtements:Automobiles -- Peinture Composites à fibres de carbone Eléments finis, Méthode des Polyamides Un polyamide est un polymère contenant des fonctions amides -C(=O)-NH- résultant d'une réaction de polycondensation entre les fonctions acide carboxylique et amine. Selon la composition de leur chaîne squelettique, les polyamides sont classés en aliphatiques, semi-aromatiques et aromatiques. Selon le type d'unités répétitives, les polyamides peuvent être des homopolymères ou des copolymères. Revêtements -- Finition:Peinture -- Finition Surfaces (Physique) Surfaces courbes Topographie Index. décimale : 667.9 Revêtements et enduits Résumé : Achieving Class A appearance over fiber-reinforced substrates can be challenging. We discuss the evolving measurements used to characterize topcoated surface appearance. The influence of carbon fiber on the surface appearance of a thermoplastic resin-transfer-molding (RTM) substrate is related to differences in thermal expansion within the substrate. The mechanism identified here is then extended to several chopped-fiber-filled thermoplastic substrates where the fiber-mapping effect is manifested in a different manner. We then investigate the influence of thick-film applications to the Class A surface on appearance. Our analysis finds that both the depth and the width or wavelength of the substrate affect the ability of the thick films to cover fiber mapping. Note de contenu : - Class a appearance defined and measured - Mechanism of fiber influence on appearance - Potential solutions - Ongoing projects in this area - Fig. 1 : Constituent Wave Packets from BYK-Gardner Wavescan - Fig. 2 : Cross section of RTM substrate - Fig. 3 : Topography of topcoated RTM substrate at 25°C adn 90°C - Fig. 4 : Topography of uncoated RTM substrate at 25°C and 90°C - Fig. 5 : RTM plaque : resin-only area CTE - Fig. 6 : Effect of fiber on topcoated appearance at bake and room temperatures - Fig. 7a and 7b : Effect of fiber on substrate surface at bake and room temperatures - Fig. 8 : Wavescan values for varied primer thicknesses - Fig. 10 : Relationship of primer thickness to defect wavelength ratio to defect coverage - Fig. 11 : Finite Element Analysis of defect propagation through primer - Fig. 12a and 12b : Appearance values for topcoat processes on carbon-fiber-filled polyamide and propylene - Table 1 : Changes of topography with temperature - Table 2 : Finite Element Analysis of varied primer thickness, wavelength, and poisson's ratio En ligne : https://drive.google.com/file/d/16c5zuNUS2yU5gQUhSR_1URCxd_BXHbzq/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35988 [article]

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An improved accelerated weathering protocol to anticipate Florida exposure behavior of coatings / Mark Nichols in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 10, N° 2 (03/2013)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 10, N° 2 (03/2013) . - p. 153-173 Titre : An improved accelerated weathering protocol to anticipate Florida exposure behavior of coatings Type de document : texte imprimé Auteurs : Mark Nichols, Auteur ; John Boisseau, Auteur ; Lynn Pattison, Auteur ; Don Campbell, Auteur ; Jeff Quill, Auteur ; Jacob Zhang, Auteur ; Don Smith, Auteur ; Karen Henderson, Auteur ; Jill Seebergh, Auteur ; Douglas Berry, Auteur ; Tony Misovski, Auteur ; Cindy Peters, Auteur Année de publication : 2013 Article en page(s) : p. 153-173 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Automobiles -- Revêtements:Automobiles -- Peinture Avions -- Revêtements:Avions -- Peinture Durée de vie (Ingénierie) Essais accélérés (technologie) Revêtements -- Détérioration Vieillissement Index. décimale : 667.9 Revêtements et enduits Résumé : A new accelerated weathering protocol has been developed which closely replicates the performance of automotive and aerospace coating systems exposed in South Florida. IR spectroscopy was used to verify that the chemical composition changes that occurred during accelerated weathering in devices with a glass filter that produced a high fidelity reproduction of sunlight’s UV spectrum matched those that occurred during natural weathering. Gravimetric water absorption measurements were used to tune the volume of water absorption during accelerated weathering to match that which occurred during natural weathering in South Florida. The frequency of water exposure was then scaled to the appropriate UV dose. A variety of coating systems were used to verify the correlation between the physical failures observed in the accelerated weathering protocol and natural weathering in South Florida. The new accelerated weathering protocol correctly reproduced gloss loss, delamination, cracking, blistering, and good performance in a variety of diverse coating systems. For automotive basecoat/clearcoat paint systems, the new weathering protocol shows significant acceleration over both Florida and previous accelerated weathering tests. For monocoat aerospace systems, the new weathering protocol showed less acceleration than for automotive coatings, but was still an improvement over previous accelerated tests and was faster than Florida exposure. Note de contenu : - EXPERIMENTAL : Materials - Natural weathering - Accelerated weathering - PAS-FTIR spectroscopy - Ultraviolet - Gloss and color change - Visual evaluation - Water sorption - RESULTS : Water absorption - Photochemistry - Physical failures of paint systems - Aerospace coatings - DISCUSSION : Water absorption - Spectral match to sunlight - Cyclic conditions - Acceleration of new tet protocol - Positive controls - UVA longevity - Aerospace coatings DOI : 10.1007/s11998-012-9467-x En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-012-9467-x.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18235 [article]

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The evolution of surface texture in automotive coatings / Cindy Peters in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 8, N° 4 (07/2011)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 8, N° 4 (07/2011) . - p. 469-480 Titre : The evolution of surface texture in automotive coatings Type de document : texte imprimé Auteurs : Cindy Peters, Auteur ; Mark E. Nichols, Auteur ; Kevin R. J. Ellwood, Auteur Année de publication : 2011 Article en page(s) : p. 469-480 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Automobiles -- Revêtements:Automobiles -- Peinture Revêtements -- Texture Rhéologie Index. décimale : 667.9 Revêtements et enduits Résumé : The curing behavior and texture development of automotive clearcoats was studied by noncontacting profilometry and dynamic viscosity measurements during solvent evaporation and thermal curing. The changing surface texture was shown to be a strong function of temperature and solvent content. Leveling occurred during the initial heating of the clearcoats, while smaller wavelength roughness was observed to appear during cooling after curing. The dynamic viscosity was shown to be a strong function of catalyst loading. Numerical simulations were conducted to calculate the apparent viscosity during the leveling process. Calculated viscosity profiles matched theoretical predictions for the behavior of these clearcoats. Note de contenu : EXPERIMENTAL METHODS : Materials - Rheology measurements - Surface profile - Weight loss - Spray application LEVELING MODEL : Governing equations - Boundary conditions - Finite-element formulation EXPERIMENTAL RESULTS : Modeling results DOI : 10.1007/s11998-011-9333-2 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-011-9333-2.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=12135 [article]

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Use of reactable light stabilizers to prevent migration and to improve durability of coatings On plastic substrates / Nancy Cliff in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 2, N° 5 (01/2005)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 2, N° 5 (01/2005) . - p. 371-387 Titre : Use of reactable light stabilizers to prevent migration and to improve durability of coatings On plastic substrates Type de document : texte imprimé Auteurs : Nancy Cliff, Auteur ; Karlis Adamsons, Auteur ; Phillip V. Yaneff, Auteur ; Cindy Peters, Auteur ; Mouhcine Kanouni, Auteur Année de publication : 2005 Article en page(s) : p. 371-387 Note générale : Bibliogr. Langues : Américain (ame) Tags : Etude  expérimentale  Durabilité  Dégradation  photochimique  Vieillissement  accéléré  Pipéridine  dérivé  Triazine  Absorbant  UV  Stabilisant  Additif  Relation  formulation  propriété  Peinturage  Procédé  revêtement  Matériau  revêtu  Elastomère  Mélange  polymère  Oléfine  Caoutchouc  thermoplastique Index. décimale : 667.9 Revêtements et enduits Résumé : One of the challenges of coating plastic substrates for exterior automotive applications involves the tendency for light stabilizers, which inhibit UV degradation of the coating, to migrate out of the topcoat and into the underlying plastic substrate. The consequent depletion of the stabilizer from the topcoat could account for significantly poorer durability for coatings applied on plastic than on a nonpermeable substrate such as steel. These studies investigate the migration of both nonreactable and reactable UV absorbers (UVAs) and hindered amine light stabilizers (HALS) in fully formulated 2K urethane coatings applied on thermoplastic olefin (TPO) and steel substrates. Extensive migration of the nonreactable stabilizers occurs during accelerated exposure of the cured coating, and this migration correlates with poorer performance on TPO. Functionalization of the stabilizer with a group which covalently reacts into the coating will prevent much of this migration, and the improved degree of retention of the reactable light stabilizers in the topcoat correlates with improved performance on TPO substrates. In addition, stabilizer variables, such as the type and extent of functionalization as well as their chemical structure, have an effect on both the migration and performance of the stabilizers. DOI : 10.1007/s11998-005-0005-y En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-005-0005-y.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3727 [article]

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