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Novel metal-free catalysts for epoxy carboxy coatings / Ravi Ravichandran in COATINGS TECH, Vol. 16, N° 3 (03/2019)  

[article]  inCOATINGS TECH > Vol. 16, N° 3 (03/2019) . - p. 28-40 Titre : Novel metal-free catalysts for epoxy carboxy coatings Type de document : texte imprimé Auteurs : Ravi Ravichandran, Auteur ; Michael Emmet, Auteur ; Matthew Gadman, Auteur ; John Florio, Auteur ; Steven Woltornist, Auteur Année de publication : 2019 Article en page(s) : p. 28-40 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Automobiles -- Vernis Catalyseurs Essais accélérés (technologie) Essais de résilience Essais dynamiques Formulation (Génie chimique) Polyacryliques Réticulation (polymérisation) vernis en phase solvant Viscosité Index. décimale : 667.9 Revêtements et enduits Résumé : A new class of metal-free catalysts has been developed that promotes the crosslinking reaction of epoxy functional polymers with carboxyl functional compounds and polymers. Particularly effective at much lower cure temperatures, these catalysts provide stable single package formulations and improved resistance properties. In addition, unlike amine-based cmpounds, these catalysts do not yellow during cure or on over-bake. Note de contenu : - INTRODUCTION : Epoxy acid automotive clearcoats - Epoxy acid-based powder coatings - Binder, crosslinking chemistry, and catalysis - EXPERIMENTAL : Experiment I : catalyst studies on NACURE XC-324 in a 1K SP epoxy/carboxy clearcoat (Materials and preparation of 1K SB epoxy/carboxy clearcoat formulation - Film preparation of 1K SB epoxy/carboxy clearcoats - Film properties of catalyzed clearcoats - Viscosity stability of epoxy carboxy liqiud coatings - Gel fraction studies - QUV resistance of catalyzed epoxy carboxy coatings - Humidity exposures of catalyzed epoxy carboxy coatings - Crickmeter abrasion - Overbake resistance) - Experiment II : Catalyst studies on NACURE XC-355 in a 2K SB epoxy/carboxy clearcoat (materials and preparation of 2K SB/epoxy carboxy clearcoat formulation - Film preparation of 2KSB epoxy/carboxy clearcoat - Film preparation of HMMM crosslinked acrylic and epoxy/carboxy clearcoats - Cure response of acrylic OH/HMMM and acrylic COOH/GMA - Environmental etch comparison of acrylic OH/HMMM vs acrylic COOH/GMA - Fig. 1 : Epoxy carboxy crosslinking reaction - Fig. 1a : Viscosity stability of epoxy/carboxy SB coatings (60°C storage) - Fig. 1b : Viscosity stability of epoxy/carboxy SB coatings (50°C storage) - Fig. 1c : Viscosity stability of epoxy/carboxy SB coatings (ambient storage) - Fig. 2 : Percent weight retention after 6h of reflux with acetone/metanol (1/1) - Fig. 3 : Yellowness measurements after QUV exposure - Fig. 4 : Change in gloss following crockmeter abrasion - Fig. 5 : Yellowing (b*) and total color (E*) change of clearcoats after overbake - Fig. 6 : Oscillation curve of complet viscosity and temperature as a function of time - Fig. 7 : MEK resistance of hardness of epoxy/acid clearcoats-100°C/30 min bake - Table 1 : Classes of available catalyst technologies - Table 2 : 1K SB epoxy/carboxy clearcoat - Table 3a : Film properties of carboxy functional acrylic and GMA epoxy-120°C/30 min - Table 3b : Film properties of carboxyl functional acrylic and GMA epoxy - 110°C/30 min - Table 4 : Viscosity stability of epoxy carboxy liquid coatings (60°C/16 h) - Table 5 : Gel fraction studies after 6h Soxhlet extraction with acetone/methanol (1/1) - Table 6 : Yellowness measurements after QUV exposure-b*values - Table 7 : Yellowness measurements after QUV exposure-Δ*values - Table 8 : Humidity exposures of catalyzed epoxy/carboxy coatings-Blister ratings - Table 9 : Visual rating for crockmeter tests-0-R rating - Table 10 : Images with visual rating and change in gloss following crockmeter abrasion - Table 11 : Change in color values of catalyzed clearcoats after overbake - Table 12 : 2K solventborne epoxy/carboxy clearcoat - Table 13a : Pre-experiment steps for oscillation tests - Table 13b : Protocol for oscillation tests - Table 14 : Film properties of carboxyl functional acrylic and GMA epoxy-100°C/30 min - Table 15 : Yellowing resistance follwing 100°C/30 min overbake - Table 16 : Total color change following 100°C/30 min overbake - Table 17 : (a) Hydroxyl functional acrylic/HMMM vs (b) acid functional acrylic/GMA epoxy - Table 18 : MEK resistance of (a) acrylic OH/HMMM vs (b) acrylic COOH/GMA - Table 19 : Acid etch resistance of (a) acrylic OH/HMMM vs (b) acrylic COOH/GMA En ligne : https://drive.google.com/file/d/1hbklMv6qE5mymZKYqIQ2MXKYVZtkH1VA/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=32045 [article]

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Polyamine curing agents meeting the industry need for enhanced productivity / Michael Cook in COATINGS TECH, Vol. 16, N° 3 (03/2019)  

[article]  inCOATINGS TECH > Vol. 16, N° 3 (03/2019) . - p. 42-54 Titre : Polyamine curing agents meeting the industry need for enhanced productivity Type de document : texte imprimé Auteurs : Michael Cook, Auteur ; Sudhir Ananthachar, Auteur ; Zheng Shiying, Auteur Année de publication : 2019 Article en page(s) : p. 42-54 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Adhésion Analyse thermique Anticorrosifs Anticorrosion Composés polycycliques Décollement cathodique (revêtement) Epoxydes Essais de brouillard salin Essais de résilience Formulation (Génie chimique) Humide sur humide (revêtements) Marines (peinture) Polyamines Polycarbamide Primaire (revêtement) Réticulants Revêtements -- Séchage sous rayonnement infrarouge proche Revêtements antisalissures:Peinture antisalissures Revêtements bi-composant Transition vitreuse Vernis Index. décimale : 667.9 Revêtements et enduits Résumé : In the challenging world of industrial, protective, and marine coatings, two-component (2K) epoxy systems are established as the benchmark technologies due to the combined offerings of excellent corrosion protection and compliance with regional volatile organic compound standards. Today, productivity has emerged as a major driver, and innovation focuses on developing epoxy coatings that have greater application versatility while providing enhanced performance properties, such as dry speed, rapid recoat, and through-cure. For marine and protective coatings, the need is for faster cure and blush-resistant coatings when applied under adverse, low temperatures conditions. In the OEM sector, the wet-on-wet application process means there is a requirement for epoxy systems to provide rapid overcoatability with polyurethane and/or polycarbamide topcoats within minutes after initial application of the primer. In this sector, the drivers are to increase overall productivity with faster application of multiple layers coupled with lower bake temperatures which can provide energy savings. This article will focus on the performance attributes of a novel polycyclic-aliphatic amine and its use in the development of new epoxy curing agents designed to provide benefit in the above markets. The supporting data includes the functional properties thermal analysis, glass transition (Tg ), and infrared (IR)-cure profile, confirming the rapid through-cure and crosslinking capabilities in epoxy systems. In addition, a review of model coating formulations and their key performance attributes, including the rapid recoat times, improved intercoat adhesion, and excellent corrosion protection properties will be discussed. Note de contenu : - Key features and benefits of the poly[HCA]amine building block - Fast property development of poly[HCA]amine - Fundamental study of fast cure mechanism of poly[HCA]amine - New polycyclic polyamide curing agents - Novel polyamide curing agents for wet-on-wet applications - Rapid recoat study using polycarbamides - Anti-corrosive primer formulation - Accelerated corrosion resistance - Cathodic disbondment - Table 1 : Properties of poly[HCA]amine - Table 2 : Summary of clear coating properties - Table 3 : Typical handling properties of rapid dry polycyclic amine polyamides - Table 4 : Tg and Mc from DMA analysis of polyamide systems - Table 5 : Base handling and performance properties of polyamide systems - Table 6 : Time to cure properties of traditional and rapid cure polyamides - Table 7 : Wet and dry adhesion properties of epoxy primers with epoxy topcoats - Table 8 : Wet/dry adhesion properties of epoxy primers with poycarbamide topcoats En ligne : https://drive.google.com/file/d/1QhY8BfKMwkQKGlF9GDpNy-kJlzV0LDr_/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=32046 [article]

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