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Interdiffusion and crosslinking in thermoset latex films / Mitchell A. Winnik in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 74, N° 925 (02/2002)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 74, N° 925 (02/2002) . - p. 49-63 Titre : Interdiffusion and crosslinking in thermoset latex films Type de document : texte imprimé Auteurs : Mitchell A. Winnik, Auteur Année de publication : 2002 Article en page(s) : p. 49-63 Note générale : Bibliogr. Langues : Américain (ame) Tags : Article  synthèse  Carbodiimide  polymère  Mélamine  résine  Acrylamide  dérivé  Diffusion  mutuelle  Réticulation  Formation  film  Thermodurcissable  Peinture  émulsion  eau  Matériau  revêtement Index. décimale : 667.9 Revêtements et enduits Résumé : Thermoset latex systems represent an attractive approach to obtaining the high performance needed in many different kinds of industrial coatings, while at the same time satisfying the growing requirement for environmental friendliness. In these coatings, in the dispersed state, the reactive groups are packaged inside of polymer particles. These latex particles deform as the coating dries to form a transparent binder phase. The useful properties of mechanical strength, as well as scrub and solvent resistance, develop over time. This paper focuses on the idea that to achieve the desired properties in a thermoset latex coating, one has to pay proper attention to the relative rates of polymer diffusion and cross-linking in the coating. Strength in these films develops as a consequence of chains that connect crosslink points on opposite sides of interface formed between a jacent particles in the film. Thus polymer diffusion must precede extensive bond formation created by the crosslinking chemistry. This paper reviews fundamental concepts and then describes experiments in three separate systems, in which my students have studied both the rates of polymer diffusion and the rates of the crosslinking reaction. These experiments show that the formulator has a number of tools that can be used to vary the relative rates of these processes. Catalyst strength and concentration will affect the reaction rote. Polymer chain length will have a large influence on the polymer diffusion rate. Temperature changes will often have a larger effect on the polymer diffusion rate than on the rate of the crosslinking reaction, because the effective activation energy for diffusion (through changes in free volume) are normally larger than the activation energy for the chemical reaction. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5674 [article]

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Life cycle environmental assessment of paint processes / Stella Papasavva in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 74, N° 925 (02/2002)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 74, N° 925 (02/2002) . - p. 65-76 Titre : Life cycle environmental assessment of paint processes Type de document : texte imprimé Auteurs : Stella Papasavva, Auteur ; Sheila Kia, Auteur ; Joseph Claya, Auteur ; Raymond Gunther, Auteur Année de publication : 2002 Article en page(s) : p. 65-76 Note générale : Bibliogr. Langues : Américain (ame) Tags : Cycle  vie  (environnement)  Déchet  industriel  solide  Pollution  air  eau  Consommation  énergie  Emission  polluant  Prévention  pollution  Protection  environnement  Peinturage Index. décimale : 667.9 Revêtements et enduits Résumé : The environmental impact of three different automotive paint scenarios: (a) solventborne primer-waterborne basecoat-solventborne clearcoat, (b) powder primer-waterborne basecoat-solventborne clearcoat, and (c) powder primer-waterborne basecoat-powder clearcoat were investigated. Scenarios (a) and (b) are in production by the U.S. automotive industry and scenario (c) is a potential future goal. The scenarios modeled assume a greenfield plant, considering a mid-size sport utility vehicle that is painted in two separate colors. A complete life cycle analysis of the materials and processes was carried out using commercial state-of-art software. The analysis showed that a transition from solvent-based to powder-based coatings for the primer and clearcoat leads to an improvement in the environmental performance of the paint processes. The decrease in total energy consumption, water usage, and sludge generation is 22%, 34%, and 27%, respectively. The paint scenario comprised of powder primer-waterborne basecoat-powder clearcoat will minimize the environmental impacts of the painting processes for all the metrics examined in this study. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5675 [article]

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Scratch resistance behavior of automotive plastic coatings / Rose Ann Ryntz in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 74, N° 925 (02/2002)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 74, N° 925 (02/2002) . - p. 77-81 Titre : Scratch resistance behavior of automotive plastic coatings Type de document : texte imprimé Auteurs : Rose Ann Ryntz, Auteur ; Dottie Britz, Auteur Année de publication : 2002 Article en page(s) : p. 77-81 Note générale : Bibliogr. Langues : Américain (ame) Tags : Microdureté  Dureté  Etude  expérimentale  Essai  rayage  Résistance  rayure  Feuil  Propriété  mécanique  Matière  plastique  Peinture  Matériau  revêtement  Industrie  automobile Index. décimale : 667.9 Revêtements et enduits Résumé : The sensitivity of automotive coatings particularly coatings for plastics, to scratching, has been a growing concern among automakers. Scratching may result from such predelivery events as polishing of minor defects embedded in the paint, or post-delivery events such as car wash ristles, dirt embedded under a cloth utilized in polishing the car, tree branches, and the like. Warranty cannot separate out which event is the more prevalent (e.g., predelivery or post-delivery to the customer) form of damage on plastics. Data available on coatings for metal, however, does suggest thot isocyanate-based crosslinked systems perform more poorly than their melamine-based crosslinked counterparts when exposed to in-plant (predelivery) handling. This work attempts to correlate the scratch resistance behavior of hydroxyl-functional acrylic or polyester-isocyanate-functionalized carbamate-melamine-, functionalized silane-melamine-, and hydroxyl-functional acrylic or polyester-melamine-crosslinked systems, both in their green state (right out of the oven, less than one week post-cure time) and in their infancy in the field (simulated 250 kJ Xenon arc Weather-ometer), to surface attributes such as toughness, hardness, and elasticity. Known scratch methodologies, namely the crockmeter and Ford five-finger laboratory test methods, in addition to a newly described compressive shear loading device (herein termed Scratcho), are used to compare the clearcoat systems as applied over one-component hydroxyl functional acrylic or polyester melamine crosslinked black basecoats. It is shown that the scratch testing methodology utilized to assess the scratch resistance of the coating system dictates results, and that Scratcho compares very well with crockmeter results. Functional carbamate-melamine crosslinked one-component coatings and functionalized silane-melamine crosslinked one-component coatings appear to outperform selected two-component coatings, which in turn outperform one-component hydroxyl functional acrylic or polyester melamine crosslinked coatings. Material attributes such as surface hardness, toughness (as measured through the method of essential work), and the ability to recover from an applied load are most important in the ability of the coating to resist damage. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5676 [article]

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Waterborne polymers for use in thermoset coatings / J. E. Blasko in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 74, N° 925 (02/2002)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 74, N° 925 (02/2002) . - p. 83-87 Titre : Waterborne polymers for use in thermoset coatings : A new hydrolysis resistant monomer as a replacement for acetoacetoxy-ethyl methacrylate Type de document : texte imprimé Auteurs : J. E. Blasko, Auteur ; G. C. Calhoun, Auteur ; R. J. Esser, Auteur ; R. E. Karabetsos, Auteur ; D. T. Krawczak, Auteur ; C. S. Giddings, Auteur ; David L. Trumbo, Auteur Année de publication : 2002 Article en page(s) : p. 83-87 Note générale : Bibliogr. Langues : Américain (ame) Tags : Acétoacétamide(N-[1-(4-isopropénylphényl)-1-méthyléthyl])  Etude  expérimentale  Hydrolyse  Propriété  chimique  Styrène  copolymère  Copolymérisation  Préparation  Acétamide  Monomère  Liant  Formulation  Thermodurcissable  Peinture  eau  Matériau  revêtement Index. décimale : 667.9 Revêtements et enduits Résumé : In an effort to obtain waterborne polymers which would yield ambient temperature cured films, we synthesized several acetoacetoxyethyl methacrylate containing copolymers. While cured films could be obtained if the copolymers were used to make films soon after they were synthesized, a decline in film performance was noted which covelated with age of the copolymer solution/ dispersion. Accordingly, we set out to synthesize a replacement for the acetoacetoxyethyl methacrylate. We decided on an amide type monomer which was synthesized in three steps from 3-isopropenyl-a,a-dimethylbenzyl isocyanate, with an overall yield of 65-70%. The new monomer did not homopolymerize but was found to copolymerize readily with styrene or n-butylacrylate. Films from polymers containing the new monomers had equal or better properties than films obtained from polymers containing acetoacetoxyethyl methacrylate. Analysis showed that the new monomer did not hydrolyze over a period of one year at ambient temperature. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5677 [article]

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