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Mechanism for environmental etch of acrylic melamine - based automotive clearcoats : identification of degredation / P. J. Schmitz in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 72, N° 904 (05/2000)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 72, N° 904 (05/2000) . - p. 39-45 Titre : Mechanism for environmental etch of acrylic melamine - based automotive clearcoats : identification of degredation Type de document : texte imprimé Auteurs : P. J. Schmitz, Auteur ; Joseph W. Holubka, Auteur ; Li - Feng Xu, Auteur Année de publication : 2000 Article en page(s) : p. 39-45 Note générale : Bibliogr. Langues : Américain (ame) Tags : Industrie  automobile  Matériau  revêtement  Vernis  Mélamine  résine  Acrylique  dérivé  polymère  Feuil  Dégradation  chimique  Hydrolyse  Pluie  acide  Mécanisme  réaction  Produit  Etude  expérimentale  Peinture Index. décimale : 667.9 Revêtements et enduits Résumé : This paper focuses on defining the reaction mechanism involved in the environmental etch of acrylic melaminic-based automative clearcoats via an identification of reaction products. This has been accomplished through a comparative study of products formed on acid treatment of neat crosslinkers, and those formed following laboratory acid treatment and field exposure of acrylic melamine clearcoat systems. Bulk elemental, X-ray photoelectron spectroscopy (XPS), and infrared (IR) analyses of sulfuric acid-treated melamine crossllinkers show that acid hydrolysis results primarily in the formation of melamine sulfate. Melamine sulfate formation was also observed following laboratory and field exposure of acrylic melamine clearcoat systems. These results confirm that the primary mode of melamine crosslink decomposition is through hydrolysis of acetal linkages and subsequent formation of melamine sulfate. However, data show that hydrolysis of pendent amino groups on the triazine ring also occurs. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5805 [article]

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Scratch resistance behavior of model coating systems / Rose Ann Ryntz in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 72, N° 904 (05/2000)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 72, N° 904 (05/2000) . - p. 47-53 Titre : Scratch resistance behavior of model coating systems Type de document : texte imprimé Auteurs : Rose Ann Ryntz, Auteur ; B. D. Abell, Auteur ; G. M. Pollano, Auteur ; L. H. Nguyen, Auteur ; W. C. Shen, Auteur Année de publication : 2000 Article en page(s) : p. 47-53 Note générale : Bibliogr. Langues : Américain (ame) Tags : Industrie  automobile  Matériau  revêtement  Peinture  Propriété  mécanique  Feuil  Résistance  rayure  Température  transition  vitreuse  Densité  réticulation  Etude  expérimentale Index. décimale : 667.9 Revêtements et enduits Résumé : Coatings are often subjected to physical deformations caused by car wash brushes, three limbs, keys, fingernails, and the like, which may results in mechanical abrasion. The resistance of the coating to scratches imposed by such mechanical abrasions has been studied through the utilization of laboratory tests such as nanoindentors, crockmetyers, scanning proble microscopes, and taber abraders. Little emphasis, however, has been placed on the influence of coating attributes on measured scratch resistance. In this study we attempt to relate the effect of coating glass transition temperature, crosslink density, and crosslink type in a series of formulated waterborne polyurethane dispersion clearcoats on resultant scratch resistance. Methods utilized to impart the scratches, e.g., scanning probe microscopy, weighted fingernail, and crockmeter, as well as related coating physical properties measured, e.g., viscoelastic behavior, hardness, and tensile strength, are discussed. The scratch resistance of model coating systems analyzed was found to be dependent upon the base resint Tg, which affected the surface hardness of the coating and the toughness of the crosslinked network, as measured by the method of essential work. Coatings that exhibited both hard surfaces and tough-elastic network integrity afforded the optimized scratch resistance behavior. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5806 [article]

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Novel synthesis of carboxy - functional soybean acrylic - alkyd resins for water - reducible coatings / Changchun Wang in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 72, N° 904 (05/2000)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 72, N° 904 (05/2000) . - p. 55-61 Titre : Novel synthesis of carboxy - functional soybean acrylic - alkyd resins for water - reducible coatings Type de document : texte imprimé Auteurs : Changchun Wang, Auteur ; Geng Lin, Auteur ; Joon-Hwan Pae, Auteur ; Frank N. Jones, Auteur Année de publication : 2000 Article en page(s) : p. 55-61 Note générale : Bibliogr. Langues : Américain (ame) Tags : Alkyde  résine  Acrylate  copolymère  Matériau  revêtement  Préparation  Polycondensation  Huile  soja  Méthacrylique  acide  Acrylique  Polyélectrolyte  Relation  composition  propriété  Stabilité  chimique  Hydrolyse  stockage  Utilisation  Peinture  eau  Etude  expérimentale Index. décimale : 667.9 Revêtements et enduits Résumé : A new process was developed for synthesis of alkyd resins in which a conventional monoglyceride is reacted with a carboxy-functional acrylic ceride is reacted with a carboxy-functional acrylic copolymer. The novel products are called acrylic-alkyd resins. The carboxy-functional acrylic copolymers were synthesized by solution-free radical polymerization. Gelation during alkyd resin synthesis was avoided by; (1) limiting the molecular weight of the acrylic copolymers to Mn 3500-5000 and (2) limiting the number average functionality about 6.5-10 carboxyl groups per molecule. Further, the carboxyl groups were derived from a mixture of acrylic and methacrylic acids (1/1.2 mol ratio) in the expectation that this would help control the process. Three series of acrylic copolymers were prepared from various combinations of acrylic monomers and reacted with a monoglyceride prepared from soybean oil and trimethylol propane. The composition of the acrylic resin was adjusted to minimize phase separation [observed visually and by scanning probe microscopy (SPM)] within cast films. The most satisfactory results were obtained with copolymers of 62-71 wt% of methyl methacrylate, 5-21 wt% of lauryl methacrylate, 7.2 wt% of acrylic acid, and 10.3 wt% of methacrylic acid, In preliminary tests, waterborne coatings made from acrylic-alkyd resins based on these acrylics had excellent stability, with acid numbers changing less than 10% after nine months of storage. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5807 [article]

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Effect of crosslinker reaction rate on film properties for thermoset coatings / Ward T. Brown in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 72, N° 904 (05/2000)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 72, N° 904 (05/2000) . - p. 63-70 Titre : Effect of crosslinker reaction rate on film properties for thermoset coatings Type de document : texte imprimé Auteurs : Ward T. Brown, Auteur Année de publication : 2000 Article en page(s) : p. 63-70 Note générale : Bibliogr. Langues : Américain (ame) Tags : Matériau  revêtement  Peinture  Formation  film  Réticulation  Réticulant  Carbodiimides  Feuil  Propriété  mécanique  Etude  expérimentale  Thermodurcissable  émulsion  eau  Acrylique  dérivé  polymère  Styrène  Cinétique Index. décimale : 667.9 Revêtements et enduits Résumé : With thermoset coatings that employ room temperature crosslinkers, there is often, a competition between film formation and crosslinking. In order to meet the early use/handling requireements for the coated substrate, formulators sometimes need to use crosslinkers with very fast room temperature reaction rates. However, when the coatings are based on aqueous latex resins, sufficient time must be allowed for latex particle coalescence to occur prior to crosslinking, or the resulting films will be partially or completely precross-linking, which is detrimental to many coatings properties. In this paper the effect of the crosslinker reaction rate on various film properties of coatings based on acrylic and acrylic/styrene latex resins will be investigated using several model carbodiimide-functional crosslinkers which have different reaction rates. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5808 [article]

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New developments in radiation - curable powder coatings / Saskia Udding-Louwrier in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 72, N° 904 (05/2000)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 72, N° 904 (05/2000) . - p. 71-75 Titre : New developments in radiation - curable powder coatings Type de document : texte imprimé Auteurs : Saskia Udding-Louwrier, Auteur ; E. Sjoerd de Jong, Auteur ; Richard A. Baijards, Auteur Année de publication : 2000 Article en page(s) : p. 71-75 Note générale : Bibliogr. Langues : Américain (ame) Tags : Matériau  revêtement  Peinture  poudre  Durcissement  Rayonnement  UV  Polymérisation  photochimique  Fabrication  Peinturage  Utilisation  Métal  Panneau  fibre Index. décimale : 667.9 Revêtements et enduits Résumé : Radiation-curable powder coatings are now in the early stages of commercialization. For years, the coatings industry has sought ways to lower the curing temperature of powder coatings UV-curable powder coatings offer the possibility of curing powder coatings at temperatures as low at 120°C. Radiation-curable powder coatings also offer high cure speed and relatively low energy consumption. As each application requires its own coating performance two different maleate-vinyl ether-based binders for UV-curable poteder coatings have been developed. With these binders the balance between flexibility and hardness of the coating can be adjusted with proper formulation. In this paper, the curing characteristic and coating performance of several UV-powder coating formulations are described In addition, a comparison between concentional powder coatings and UV-powder coatings is provided. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5809 [article]

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