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Effect of carbon black on adhesion to plastics in solventborne 2K polyurethanes / Kalpana S. Katti in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 72, N° 903 (04/2000)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 72, N° 903 (04/2000) . - p. 35-44 Titre : Effect of carbon black on adhesion to plastics in solventborne 2K polyurethanes Type de document : texte imprimé Auteurs : Kalpana S. Katti, Auteur ; Marek W. Urban, Auteur Année de publication : 2000 Article en page(s) : p. 35-44 Note générale : Bibliogr. Langues : Américain (ame) Tags : Matériau  revêtement  Peinture  Uréthanne  polymère  Pigment  minéral  Noir  carbone  Concentration  pigmentaire  volumique  Réticulation  Adhérence  Matière  plastique  ABS  Etude  expérimentale Index. décimale : 667.9 Revêtements et enduits Résumé : These studies show that when the pigment volume content (PVC) of carbon black particles increases in polyurethanes (PUR), NCO consumption increases, and the extent of H-bonded C=O species near the film-substrate (F-S) interface is enhanced. During crosslinking, polyurea (PUA) is produced, and its concentration levels near the F-S interface are diminished for unpigmented coatings, whereas for the same system containing carbon black, the PUA formation is enhanced. Although the presence of carbon black particles at the F-S interface results in diminished adhesion of 2K PUR to acrylonitrile-butadiene-styrene (ABS), adhesion is also affected by the presence of OH and C=O functionalities on ABS, which are potential sites for H- bonding to PUR. Stronger hydrogen donor affinity of N-H functionalities in PUA as compared to the N-H groups on PUR leads to increased H-bonding in the presence of carbon black. Enhanced intermolecular H-bonding in PUR due to the presence of carbon black particles competes with the F-S interfacial H-bonding that promotes adhesion. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5815 [article]

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Polymer diffusion and mechanical properties of films prepared from crosslinked latex particles / Patrick Pinenq in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 72, N° 903 (04/2000)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 72, N° 903 (04/2000) . - p. 45-61 Titre : Polymer diffusion and mechanical properties of films prepared from crosslinked latex particles Type de document : texte imprimé Auteurs : Patrick Pinenq, Auteur ; Mitchell A. Winnik, Auteur ; Benoit Ernst, Auteur ; Didier Juhué, Auteur Année de publication : 2000 Article en page(s) : p. 45-61 Note générale : Bibliogr. Langues : Américain (ame) Tags : Matériau  revêtement  Peinture  eau  émulsion  Formation  film  Latex  Réticulation  Polymère  Diffusion  Transfert  énergie  Propriété  mécanique  Feuil  Résistance  traction  Etude  expérimentale Index. décimale : 667.9 Revêtements et enduits Résumé : We have carried out energy transfer (ET) measurements to follow polymer diffusion, as well as oscillatory dynamic mechanical measurements and tensile measurements, on films prepared from structured and unstructured latex particles. All the particles had the same global chemical composition. The base polymer was a copolymer of butyl methacrylate and butyl acrylate with a glass transition temperature (Tg) of 20°C. Structure was introduced in the form of a low level (1 mol%) of crosslinking using seeded semi-continuous emulsion polymerization to control the locus of the crosslinking agent in the particles. Most of the samples were also labeled with donor or acceptor dyes so that ET experiments could be carried out. In this way we could monitor the extent of interdiffusion that occurred in each of the latex films as a function of annealing history. These ET experiments proved to be particularly useful for determining particle morphology for core-crosslinked particles in which only the core was labeled. The linear dynamic mechanical measurements showed that G' and G were sensitive to the particle morphology, with particular sensitivity exhibited by the elastic modulus G'. The tensile properties were less sensitive to particle morphology. Films for tensile experiments were substantially thicker (0.8 mm) than those commonly used for ET studies of polymer diffusion in latex films. Film thickness has no effect on the polymer diffusion rate, but the films for tensile testing were subjected to prolonged drying at 39°C. Under these conditions, sufficient polymer interdiffusion occurs during film formation for the films to acquire substantial strength and toughness, with elongation at break much larger than 100%. Some differences due to morphology are apparent. Films formed from fully crosslinked latex and from core-crosslinked latex with a large core fraction (50 vol%) have somewhat larger tensile strengths, yield strengths, and toughness than those formed from uncrosslinked latex or latex with a small (12 vol%) crosslinked core. These differences become less pronounced when the samples are annealed for long periods of time (100+ hr) at 80°C. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5816 [article]

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Bake oven induced variation of surface chemistry on electrocoat paint / Larry P. Haack in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 72, N° 903 (04/2000)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 72, N° 903 (04/2000) . - p. 63-70 Titre : Bake oven induced variation of surface chemistry on electrocoat paint : Effect on primer-electrocoat intercoat adhesion Type de document : texte imprimé Auteurs : Larry P. Haack, Auteur ; Joseph W. Holubka, Auteur Année de publication : 2000 Article en page(s) : p. 63-70 Note générale : Bibliogr. Langues : Américain (ame) Tags : Matériau  revêtement  Peinture  Multicouche  Durcissement  Cuisson  au  four  Propriété  surface  Adhérence  Interface  Dépôt  électrophorèse  Etude  expérimentale Index. décimale : 667.9 Revêtements et enduits Résumé : The interplay of bake oven processing environment and surface/interfacial chemistry, and their effect on intercoat adhesion has been investigated for a model primer/electrocoat paint system. X-ray photoelectron spectroscopy (XPS) surface analysis established that a prominent ether component in the C is core level spectrum correlated with a polyether-based crater-control additive in the electrocoat that surface-segregates during cure. Laboratory-simulated bake oven experiments confirmed that better adhesion characteristics were realized by removal of this electrocoat overlayer through reaction with nitrogen oxides and high levels of moisture present in the cure environment of production direct-fired ovens. Details of the effect of bake oven atmosphere on cure chemistry for direct-fired versus indirect-fired ovens are presented. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5817 [article]

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Effect of extenders with narrow and broad particle size distributions on the properties of coatings / Rüdiger Werner in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 72, N° 903 (04/2000)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 72, N° 903 (04/2000) . - p. 71-76 Titre : Effect of extenders with narrow and broad particle size distributions on the properties of coatings Type de document : texte imprimé Auteurs : Rüdiger Werner, Auteur Année de publication : 2000 Article en page(s) : p. 71-76 Note générale : Bibliogr. Langues : Américain (ame) Tags : Matériau  revêtement  Peinture  Matière  charge  Granularité  émulsion  Propriété  optique  Feuil  Opacité  Brillant  Calcium  Carbonate  Etude  expérimentale  CaCO3 Index. décimale : 667.9 Revêtements et enduits Résumé : Extenders are manufactured in a wide range of finenesses enabling paint formulators to influence specific properties of the finished paint. It is necessary to know the granulometry or particle size distribution of the extender to select the appropriate one to achieve the desired properties. Two extenders with practically the same top cut, but one with a broad particle size distribution curve, and the other one with a narrow or steep particle size distribution curve, were compared in four different coating systems. The extender with a narrow particle size distribution offered some advantages over the finer one with a broader particle size distribution. The technical advantages of using such extenders over those with broad curves but similar finenesses are, in particular: ease of dispersion, higher opacity, haze-free gloss, shortening of the drying time, and spacing properties for titanium dioxide. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5818 [article]

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Zero VOC sunlight curable coatings / Huilei Zhang in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 72, N° 903 (04/2000)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 72, N° 903 (04/2000) . - p. 77-79 Titre : Zero VOC sunlight curable coatings Type de document : texte imprimé Auteurs : Huilei Zhang, Auteur ; John L. Massingill, Auteur ; J. T. K. Woo, Auteur Année de publication : 2000 Article en page(s) : p. 77-79 Note générale : Bibliogr. Langues : Américain (ame) Tags : Matériau  revêtement  Peinture  photodurcissable  Epoxyde  résine  Durcissement  Rayonnement  UV  Lumière  solaire  Etude  expérimentale Index. décimale : 667.9 Revêtements et enduits Résumé : Curing of one-pack epoxy coatings by exposure to visible light for a few hours would be a useful innovation for architectural, industrial, and maintenance (AIM) coatings as well as for any large objects that would be difficult to heat but easy to shine a light on. Zero VOC, low viscosity, sunlight curable clearcoats can be formulated with cycloaliphatic epoxy compounds as well as aromatio glycidyl ethers. Cure is achieved with a cationic photoinitiator that generates a strong acid when exposed to sunlight for a couple of hours. The clearcoats had good hardness, adhesion, and solvent resistance. No cure was achieved with incandescent light or with fluorescent light, which contains only 0.1% UV light as compared to sunlight that has 5% UV light. This work indicates that zero VOC one pack clearcoat epoxy formulations for AIM applications and large objects could be cured by light racks that generate the spectrum of sunlight. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5819 [article]

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