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Novel cashew nutshell liquid-based waterborne curing agents designed for high-performance and low-VOC protective epoxy coatings / Hong Xu in COATINGS TECH, Vol. 17, N° 5 (05/2020)  

[article]  inCOATINGS TECH > Vol. 17, N° 5 (05/2020) . - p. 18-27 Titre : Novel cashew nutshell liquid-based waterborne curing agents designed for high-performance and low-VOC protective epoxy coatings Type de document : texte imprimé Auteurs : Hong Xu, Auteur ; Joe Mauck, Auteur ; Fernanda Tavares, Auteur ; Anbu Natesh, Auteur ; Jing Li, Auteur Année de publication : 2020 Article en page(s) : p. 18-27 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Epoxydes Essais de brouillard salin Formulation (Génie chimique) Noix de cajou et constituants Primaire (revêtement) Réticulants Réticulants en phase aqueuse Index. décimale : 667.9 Revêtements et enduits Résumé : A series of zero-volatile organic compound (VOC) waterborne epoxy curing agents based on cardanol, a non-food chain and renewable biomaterial, has been developed to meet stricter regulation, as well as high-performance requirements. This article presents the latest performance studies of applying those new Cashew Nutshell Liquid-based waterborne curing agents in typical formulations for heavy duty, industrial, and transportation coatings applications. Test results revealed that the novel waterborne curing agents enable the formulations of low-VOC (< 75 g/L) direct-to-metal primer systems with excellent performance, such as balanced fast cure and long pot life, superior adhesion, and long-term corrosion protection of numerous metal substrates. Furthermore, the influence of various solid epoxy dispersions, different cure processes, and co-solvents upon film formation, adhesion, and anti-corrosion performance are reviewed, and the challenges of improving long-term corrosion protection of waterborne primer systems over galvanized steel substrates are discussed. Note de contenu : - Part 1 : Improved application properties from new waterborne curing agents - Part 2 : Waterborne primer/mid-coat systems based on new WB-A and WB-B curing agents - Part 3 : Wet-on-wet properties - Part 4 : Formulation study - Fig. 1 : Cashew apple and nutshell - Fig. 2 : Average cardanol structure - Fig. 3 : Viscosity changes of waterborne curing agents as function of the percentage of added water - Fig. 4 : Diluation properties of WB-A with various solid epoxy dispersions - Fig. 5 : Linear dry time data ov various waterborne systems - Fig. 6 : Persoz hardness development of various waterborne systems - Fig. 7 : Panel images of WB-A/MC#1, WB-B/MC#2 and COM/MC#3 system after 1162 h, 949 h of salt-spray exposure, respectively (SA 2.5 steel substrate, bake cure, DFT = 60-75 µm) - Fig. 8 : Panel images of WB-A/MC#1, WB-B/MC#2 and COM/MC#3 system after 1162 h, 949 h and 1162 of salt-spray exposure, respectively (S-36 CRS substrate, bake cure, DFT = 75 µm) - Fig. 9 : Panel images of WB-A/MC#1, WB-B/MC#2 and COM/MC#3 system after 2018 h, 1852, and 2018 h of salt-spray exposure, respectively (AA 2024 T3 substrate, bake cure, DFT = 65 µm) - Fig. 10 : Panel images of WB-A/MC#1, WB-B/MC#2 and COM/MC#3 system after 996 h, 949 h of salt-spray exposure, respectively (stainless steel substrate, RT cure, DFT = 65 µm) - Fig. 11 : Panel images of WB-A/MC#1, WB-B/MC#2 and COM/MC#3 system after 1115 h, 949 h of salt-spray exposure, respectively (galvanized steel substrate, RT cure, DFT = 65 µm) - Fig. 13 : Photo images of the wet-on-wet application panels after 881 h of salt-spray exposure - Fig. 14 : Panel images of MC#4 system, MC#5 system and MC#5 system after 750 h of salt-spray exposure (galvanized steel substrate, RT cure, DFT = 50-60 µm) - Fig. 15 : Panel images of MC#4 system, MC#5 system and MC#7 system after 750 h of salt-spray exposure (galvanized steel substrate, RT cure, DFT = 50-60 µm) - Fig. 16 : Panel images of five waterborne primer systems containing different co-solvents after a 20-h RT aging - Table 1 : Waterborne curing agents - Typical properties - Table 2 : Typical properties of solid epoxy dispersion resins - Table 3 : Waterborne primer formulations based on WB-A, WB-B, and COM - Table 4 : Dry and wet adhesion of WB-1, WB-B, and COM system over various metal substrates - Table 5 : Waterborne primer formulations based on WB-A - Table 6 : Gloss retention of the test panels after wet-on-wet application - Table 7 : Property tests using different solvents En ligne : https://drive.google.com/file/d/1XacND7z3Wh6j3ngkyWrPxrafLk0n_1E-/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34303 [article]

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Engineered polysaccharides / Stephen Raper in COATINGS TECH, Vol. 17, N° 5 (05/2020)  

[article]  inCOATINGS TECH > Vol. 17, N° 5 (05/2020) . - p. 28-39 Titre : Engineered polysaccharides : A novel biomaterial additive with multifunctional properties Type de document : texte imprimé Auteurs : Stephen Raper, Auteur ; Sara Harris, Auteur ; Doug Corrigan, Auteur ; Kyle Kim, Auteur ; Christian Lenges, Auteur Année de publication : 2020 Article en page(s) : p. 28-39 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Biomatériaux Chlorure de polyvinyle Copolymère éthylène acétate de vinyle Dioxyde de titane Formulation (Génie chimique) Glucanes Un glucane est un polysaccharide (polymère d'oses) composé exclusivement de monomère de glucose. Ils peuvent être linéaires ou bien ramifiés. Kaolin Latex Polysaccharides Les polysaccharides (parfois appelés glycanes, polyosides, polyholosides ou glucides complexes) sont des polymères constitués de plusieurs oses liés entre eux par des liaisons osidiques. Les polyosides les plus répandus du règne végétal sont la cellulose et l’amidon, tous deux polymères du glucose. De nombreux exopolysaccharides (métabolites excrétés par des microbes, champignons, vers (mucus) du ver de terre) jouent un rôle majeur - à échelle moléculaire - dans la formation, qualité et conservation des sols, de l'humus, des agrégats formant les sols et de divers composés "argile-exopolysaccharide" et composites "organo-minéraux"(ex : xanthane, dextrane, le rhamsane, succinoglycanes...). De nombreux polyosides sont utilisés comme des additifs alimentaires sous forme de fibre (inuline) ou de gomme naturelle. Ce sont des polymères formés d'un certain nombre d'oses (ou monosaccharides) ayant pour formule générale : -[Cx(H2O)y)]n- (où y est généralement x - 1). On distingue deux catégories de polysaccharides : Les homopolysaccharides (ou homoglycanes) constitués du même monosaccharide : fructanes, glucanes, galactanes, mannanes ; les hétéropolysaccharides (ou hétéroglycanes) formés de différents monosaccharides : hémicelluloses. Les constituants participant à la construction des polysaccharides peuvent être très divers : hexoses, pentoses, anhydrohexoses, éthers d'oses et esters sulfuriques. Selon l'architecture de leur chaîne, les polysaccharides peuvent être : linéaires : cellulose ; ramifiés : gomme arabique, amylopectine, dextrane, hémicellulose et mixtes : amidon. Résistance aux taches Revêtements -- Additifs:Peinture -- Additifs Revêtements -- Propriétés optiques:Peinture -- Propriétés optiques Revêtements en bâtiment:Peinture en bâtiment Revêtements organiques Rhéologie Index. décimale : 667.9 Revêtements et enduits Résumé : Advances in the performance of formulated products through material innovation continue to drive innovation and growth. At the same time, it is becoming increasingly paramount that new materials are also sourced from ideally renewable and overall more sustainable feedstocks using benign processes to meet criteria required within a circular economy context. Progress in architectural and industrial coatings has focused on providing not only improved paint performance but also optimizing aspects such as pigment efficiency (e.g., reduction of TiO2) and effective gloss management, while maintaining key characteristics such as abrasion performance and overall coating properties. At the same time, continued emphasis has been placed on reducing the environmental footprint through lower volatile organic content (VOC) in paint systems. In addition, increasing efforts have been directed to eventually replace typical petroleum-derived building blocks in coatings formulations with more sustainable, potentially renewable material alternatives. However, the transition to performance-advantaged renewable building blocks, which are accessible at an enabling cost position and are also based on fungible, readily available raw materials produced in a sustainable and scalable industrial process, remains challenging across material industries. This article discusses one specific example of renewable based additive technology to meet the stated industry performance needs and objectives. Note de contenu : - ENGINEERED POLYSACCHARIDE FUNDAMENTAL MATERIAL PROPERTIES - EXPERIMENTAL : VAE latex-based interior paint formulations with varying PVC - Model architectural paint formulations - Optical enhancement and displacement of TiO2 - Rheological enhancement properties of glucan - Stain resistance properties of alpha-1,3-glucan formulated paints - Fig. 1 : Illustration of the reaction producing alpha 1.3-glucan polymer - Fig. 2 : SEM image of glucan polymer from enzymatic polymerization - Fig. 3 : Shear viscosity of 7 wt% colloidal dispersion of alpha 1,3-glucan - Fig. 4 : Shear viscosity at 10 s-1 vs alpha-1,3-glucan solids concentration - Fig. 5 : Cross-section SEM images of dried drawdown film showing control formulation and formulation with TiO2 displacement of 30% for 65% and 55% PVC and of 13% for 45% PVC using alpha-1,3-glucan - Fig. 6 : TiO2, displacement performance of alpha-1,3-glucan and competitive products at different PVC formulations - Fig. 7 : Blue tint strength of alpha-1,3 glucan and benchmarks at different PVC formulations - Fig. 8 : TiO2 displacement performance of alpha-1,3 glucan, MC6, and calcined kaolin at different PVC formulations - Fig. 9 : Blue tint strength of MCG, alpha-1,3-glucan, calcined kaolin at different PVC formulations - Fig. 10 : Viscosity profile for paint formulations with glucan additives at different PVC - Fig. 11 : Stain resistance performance of glucan-formulated paints show matching performance when exposed to typical stain examples. In some cases, the glucan-containing paint is less impacted by the stain challenge - Table 1 : VAE-based model architectural paint formulations with different PVC levels - Table A1 : Formulation detail for 65% PVC system with 30% replacement of TiO2 - Table A2 : Formulation detail for 55% PVC system with 30% replacement of TiO2 for hollow acrylic latex, only 14% of TiO2 has been replaced - Table A3 : Formulation detail for 45% PVC system with 14% replacement - Table A4 : Optical properties of dried drawdown films for 65% PVC system - Table A5 : Optical properties of dried drawdown films for blue tinted 65% PVC system - Table A6 : Optical properties of dried drawdown films for 55% PVC system - Table A7 : Optical properties of dried drawdown films for blue tinted 55% PVC system - Table A8 : Optical properties of dried drawdown films for 45% PVC system - Table A9 : Optical properties of dried drawdown films for blue tinted 45% PVC system En ligne : https://drive.google.com/file/d/1Yo-uYn50Au6yDPVAiQDik-9Lmq4bPniS/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34304 [article]

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Challenging preservation options / Jessica Levin in COATINGS TECH, Vol. 17, N° 5 (05/2020)  

[article]  inCOATINGS TECH > Vol. 17, N° 5 (05/2020) . - p. 40-45 Titre : Challenging preservation options : Towards biocide-free waterborne coatings via innovative binders and additives Type de document : texte imprimé Auteurs : Jessica Levin, Auteur ; Wenqin Wang, Auteur ; Stan Brownwell, Auteur ; Tara Conley, Auteur ; Erica Frankel, Auteur ; John J. Rabasco, Auteur ; Deb Graves, Auteur ; Adrian Ward, Auteur Année de publication : 2020 Article en page(s) : p. 40-45 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Antimicrobiens -- Suppression ou remplacement Copolymère styrène acrylique Epaississants Formulation (Génie chimique) Liants Liants en phase aqueuse Polyacryliques Polyuréthane éthoxylé modifié de façon hydrophobe Revêtements en phase aqueuse -- Additifs:Peinture en phase aqueuse -- Additifs Revêtements organiques Index. décimale : 667.9 Revêtements et enduits Résumé : Increasing regulatory restrictions mean that there are limited preservation options currently available to the paint and coatings industry for both in-can and dry-film preservation. Experimental binders and thickeners that are more robust to microbial spoilage offer a potential solution and pass challenge testing even when formulated into waterborne paints. Water-based products are susceptible to microbial contamination. Contamination can be introduced during a variety of stages in the product life cycle, including manufacturing and packaging of the products ; "in can" during periods of storage, transportation, transfer, and usage; or on the dry film after application. Microbial susceptibility can cause product degradation, reduce product performance, or even induce hygiene and human health issues, which could result in a wide range of possible consequences, including product recall, customer complaints, reduced perception of product quality, production stoppage, etc. For these reasons, manufacturers add biocides to their waterborne products. There are three aspects of coating preservation. The first is in-can preservation, which protects all liquid-state products with preservatives. The second aspect of preserving coatings is dry-film protection, which protects coatings from microbes in application areas such as in bathrooms, kitchens, and on exterior surfaces. Lastly, plant hygiene is critical for coatings preservation. If a tank or a pipe becomes contaminated, it can contaminate the final product. Each of these three aspects requires a different approach for preservation. From the consumer’s perspective, the biocides that are present in the final product are the most important: both for in-can and dry-film preservation. Ideally, antimicrobial materials would maximize efficacy, while minimizing toxicity and environmental persistence. Active antimicrobial ingredients need to be stable within the shelf life of the product to maintain product quality, but also biodegradable when exposed to the environment to deliver eco-friendly products. Furthermore, they need to be effective against microbes but non-toxic to other life forms. Balancing these needs is difficult to achieve in reality. Note de contenu : - REGULATIONS NECESSITATE NEW PRESERVATION METHODS : Commercially available solutions are limited - Emerging technologies offer potential - DEVELOPMENT OF ROBUST RAW MATERIALS FOR STANDARD PH COATINGS : Experimental - Binders more robust against microbial spoilage - Paint formulated with experimental binders passes challenge tests - HEUR rheology modifiers that are less prone to microbial spoilage - Path to reducing spoilage without biocides - Table 1 : Rating system for estimating the level of microbial contamination on streak plates - Table 2 : Microbial challenge test results for various acrylic and styrene acrylic binders at pH 7.0-9.5 supplied without biocide - Table 3 : Paint formulation based on commercial and experimental soft styrene acrylic binders - Table 4 : Microbial challenge test result for various HEUR rheology modifiers supplied without biocide added, including the growth rating in parentheses as described in table 1 - Table 5 : Styrene acrylic screening formultion used to test type 1, type 2, and type HEURs for thickening performance - Fig. 1 : Paint performance data on paints based on commercial and experimental soft styrene acrylic binders - Fig. 2 : Microbial challenge test plates seven days after challenge 2 En ligne : https://drive.google.com/file/d/1B0ac2Mg2sNEOI-g5PpL-_xwhr9AZg14W/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34305 [article]

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Coatings Tech Vol. 17, N° 5 URL