Unique catalyst for low temperature cure epoxy powder coatings / Matthew Gadman in COATINGS TECH, Vol. 20, N° 1 (01-02/2023)  

[article]  inCOATINGS TECH > Vol. 20, N° 1 (01-02/2023) . - p. 18-33 Titre : Unique catalyst for low temperature cure epoxy powder coatings Type de document : texte imprimé Auteurs : Matthew Gadman, Auteur ; John Florio, Auteur ; Matt C. Salvi, Auteur Année de publication : 2023 Article en page(s) : p. 18-33 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Basses températures Bisphénol A Blanc (couleur) Catalyseurs Epoxydes Formulation (Génie chimique) Homopolymères Isocyanurate de triglycidyle Méthacrylate de glycidyle Polyacryliques Réticulation (polymérisation) Revêtements bi-composant Revêtements organiques Revêtements poudre Rhéologie Stabilité au stockage Thermodurcissables Index. décimale : 667.9 Revêtements et enduits Résumé : Powder coatings continue to ba an attractive technology, primarily due to reduced volatile organic compound (VOC) emissions, ability to recycle overspray, and the exceptional film mechanical properties that can be attained. Despite the appeal, there are major drawbacks that need to be resolved for the technology to be effectively substitutable for liquid coatings. Note de contenu : - POWDER HISTORY AND TODAY'S MARKET : Launch of thermoset powder technology-innovation and low VOC initiatives : Circa 1950-1990 - Continued growth in a variety of markets-postmillennial - Environmentally aware consumers and VOC regulations : contemporary market - A REVIEW OF THERMOSET POWDER TECHNOLOGIES : 1. Epoxy hybrids - 2. TGIC coatings (polyester) - 3. Acrylic systems - 4. Pure epoxy formulations - CATALYSTS FOR EPOXY POWDER COATINGS : - EXPERIMENTAL : Experiment I : Cure capabilities in acrylic/GMA-SB and pwoder formulations - Formulations, materials, and preparation of 2K SB acrylic/GMA and pwder acrylic/GMA - Rheology studies of 2K SB acrylic/GMA and pwder acrylic/GMA - EXPERIMENT II : Accelerating epoxy homopolymerization : Formulations, materials, and preparation of catalyzed epoxy resins - Rheology studies of catalyzed BPA epoxy resins - EXPERIMENT III : EVALUATION OF CATALYST PC IN FULLY FORMULATED WHITE EPOXY HYBRID POWDER : Formulations, materials, and preparation of white epoxy hybrid - Rheology studies of white epoxy hybrid - Film preparation of white epoxy hybrid - Film evaluation of white epoxy hybrid - Storage stability - EXPERIMENT IV : EVALUATION OF CATALYST PC IN FULLY FORMULATED WHITE TGIC POWDER : Formulations, materials, and preparation of white TGIC formulation - Rheology studies of white TGIC formulation - Film preparation of white TGIC formulation - Film evaluation of white TGIC formulation - Storage stability - Fig. 1 : Bisphenol-1 type epoxy resins, n ≥ 0 - Fig. 2 : Hydroxy ester formation via reaction of epoxides and carboxyl groups - Fig. 3 : Triglycidylisocyanurate (TGIC) crosslinker - Fig. 4 : Glycidyl methacrylate (GMA) monomer - Fig. 5 : Dicyandiamide (DICY) crosslinker - Fig. 6A : Initiating epoxy/amine polymerization - Fig. 6B : Epoxy homopolymerization via catalysis by tertiary amine - Fig. 6C : Deprotonation of hydroxyls and subsequent reactions with epoxy - Fig. 6D : Amide formation via reaction of hydroxyl with nitrile - Fig. 7A : Base catalysis : deprotonation of carboxylic acid* - Fig. 7B : Base catalysis : interaction of conjugate acid with epoxide oygen - Fig. 8 : Preparing powder disks using cylindrical pellet press - Fig. 9 : Catalyst LC gel temperature in S B and powder acrylic/GMA system - Fig. 10 : Log (lη*l) as a function of temperature : increasing dosages of catalyst LC - Fig. 11 : Gel temperatures of white epoxy hybrid - Fig. 12 : MEK resistance of white epoxy hybrids baked at various temperatures - Fig. 13 : Impact resistance of white epoxy hybrid baked at various temperatures for 15 mn - Fig. 14 : ΔΕ of catalyzed versus uncatalyzed white epoxy hybrid - Fig. 15 : Pendulum and pencil hardness of white epoxy hybrid-bake temp./ 15 mn - Fig. 16 : Log (lη*l) as a function of temperature-white TGIC formulation - Fig. 17 : Impact resistance of white TGIC formluation - % active catalyst on TRS - Fig. 18 : Gloss and color of white TGIC formulation-60° GU and b* - Table 1 : Commonly used catalysts for epoxy reaction with carboxylic acids - Table 2 : Physical properties of catalyst LC and catalyst PC - Table 3 : 2K SB acrylic/GMA formulation - Table 4 : Powder acrylic/GMA formulation - Table 5A : Pre-experiment steps for SB oscillation tests - Table 5B : Protocol for SB oscillation tests - Table 6A : Pre-experiment steps for powder oscillation tests - Table 6B : Protocol for powder oscillation tests - Table 7 : Solventless BPA epoxy resin - Table 8A : Pre-experiment steps for solventless epoxy oscillation tests - Table 8B : Protocol for solventless oscillation tets - Table 9 : Gel temp and onset temp of BPA epoxy resin with catalyst LC - Table 10A : Breakdown of components of uncatalyzed white epoxy hybrid - Table 10B : % breakdown of uncatalyzed and catalyzed white epoxy hybrid - Table 11A : Pre-experiment steps for white epoxy hybrid oscillation tests - Table 11B : Protocol for white epoxy hybrid oscillation tests - Table 12 : Color values of white epoxy hybrid : L*, a*, b* - Table 13 : Gloss properties of white epoxy hybrid-60° gloss units (GU) - Table 14 : Uncatalyzed white TGIC formulation En ligne : https://drive.google.com/file/d/1geR64CGC-_890pO1tV9GH-iQvIM2r4Eg/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38714 [article]

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