Cardanol – an eco-friendly isocyanate blocking agent / Yun mi Kim in COATINGS WORLD, Vol. 24, N° 2 (02/2019)  

[article]  inCOATINGS WORLD > Vol. 24, N° 2 (02/2019) Titre : Cardanol – an eco-friendly isocyanate blocking agent : Deblocking performances and methods to optimize deblocking temperature Type de document : texte imprimé Auteurs : Yun mi Kim, Auteur ; Anbu Natesh, Auteur ; Pietro Campaner, Auteur Année de publication : 2019 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Cardanol Catalyseurs Isocyanates Polymères -- Détérioration Polypropylène glycol Polyuréthanes Prépolymères Un pré-polymère ou prépolymère est un oligomère ou un polymère présentant des groupes réactifs qui lui permettent de participer à une polymérisation ultérieure et d’incorporer ainsi plusieurs unités monomères dans au moins une chaîne de la macromolécule finale. Les pré-polymères peuvent être di-fonctionnels (c'est le cas des pré-polymères téléchéliques) ou plurifonctionnels. Dans ce dernier cas, ils sont utilisés pour la fabrication de polymères thermodurcissables par réticulation. Structure chimique Index. décimale : 667.9 Revêtements et enduits Résumé : Cardanol, a well-known non-edible natural oil derived from the cashew nut shell liquid, is a USDA certified bio-based product. Once used as a very high purity grade (NX-2026,TM 3-pentadeca-dienyl-phenol) in PU prepolymers, this substance has demonstrated various benefits including favorable deblocking conditions, lower viscosity, and excellent storage stability compared to commonly used phenolic compounds. One of the most known deblocking methods involves exposure to elevated temperatures, i.e., 150 °C – 200 °C. However, not all substrates (e.g., plastics) and applications can accommodate such high temperatures for deblocking, thus, the possibility to optimize deblocking conditions can be a valuable tool to further expand the applicability of 3-pentadeca-dienyl-phenol as a label-friendly polyurethane prepolymers’ blocking agent. In this study, we present different approaches to control NX-2026 deblocking conditions. First, 3-pentadeca-dienyl-phenol blocked prepolymers were prepared starting from different diols (e.g., PPG, polyester, CNSL-based) as well as aromatic (MDI, TDI) and aliphatic (HDI, IPDI) isocyanates. These were subsequently characterized for their deblocking temperatures and used as model substrates for the study. Key factors for controlling deblocking conditions such as catalysts, deblocking agents (amines, polyols), and solvents were investigated. Note de contenu : - Fig. 1 : Anacardium Occidentale fruit (left) and schematic process for cardanol recovery - Fig. 2 : Examples of cardanol’s potential functionalization - Fig. 3 : NX-2026 (3-pentadeca-dienyl-phenol) chemical structure - Fig. 4 : Possible reactions of blocked isocyanates - Fig. 5 : Proposed mechanism for PU depolymerization catalyzed by dibutyltin dilaurate - Fig. 6 : Effect of chain extender (amine) on deblocking temperatures of NX-2026TM-blocked prepolymers - Table 1 : Appearance and deblocking temperatures of blocked isocyanates - Table 2 : Deblocking temperature and time for blocked PPG prepolymers - Table 3 : Typical average deblocking temperatures for different PU substrates - Table 4 : Effect of catalysts on deblocking temperatures of NX-2026-isocyanate adducts - Table 5 : Effect of catalysts on deblocking temperatures of NX-2026-blocked prepolymers - Table 6 : Effect of chain extender (polyol) and catalysts on deblocking temperatures of NX-2026-blocked prepolymers - Table 7 : Use of catalysts to tune deblocking temperatures on other types of NX-2026-blocked prepolymers - Table 8 : MW variation (%, determined by GPC) of NX-2026-blocked PPG prepolymers in presence of very effective deblocking catalysts Tegoamin 33 and DABCO K15 after storage at 50 °C for 10 days - Table 9 : MW variation (determined by GPC) of NX-2026-blocked PPG prepolymers in presence of a chain extender (propoxylated sorbitol polyol) and of very effective deblocking catalysts Tegoamin 33 and DABCO K15 after storage at 50 °C for 10 days - Table 10 : Effect of chain extender (polyol) and alternative catalysts on deblocking temperatures of NX-2026-blocked prepolymers - Table 11 : MW variation (determined by GPC) of NX-2026-blocked PPG prepolymers in presence of a chain extender (propoxylated sorbitol polyol) and of alternative catalysts after storage at 50 °C for 10 days - Table 12 : Effect of chain extender (amine) and catalysts on deblocking temperatures of NX-2026-blocked prepolymers En ligne : https://www.coatingsworld.com/issues/2019-02-01/view_technical-papers/cardanol-- [...] Format de la ressource électronique : Html Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=32507 [article]

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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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Novel CNSL-based waterborne Zn-rich primer systems for protective coatings / Hong Xu in COATINGS TECH, Vol. 15, N° 4 (04/2018)  

[article]  inCOATINGS TECH > Vol. 15, N° 4 (04/2018) . - p. 34-42 Titre : Novel CNSL-based waterborne Zn-rich primer systems for protective coatings Type de document : texte imprimé Auteurs : Hong Xu, Auteur ; Fernanda Tavares, Auteur ; Anbu Natesh, Auteur ; Jing Li, Auteur Année de publication : 2018 Article en page(s) : p. 34-42 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Anticorrosifs Anticorrosion Application directe sur le métal Brillance (optique) Cardanol Epoxydes Essais d'adhésion Essais de brouillard salin Formulation (Génie chimique) Métaux -- Revêtements protecteurs Noix de cajou et constituants Phénalkamines Polyuréthanes Primaire (revêtement) Réticulants Revêtements -- Finition Revêtements -- Propriétés mécaniques Revêtements bi-composant Revêtements en phase aqueuse Rhéologie Zinc Index. décimale : 667.9 Revêtements et enduits Résumé : Low-VOC waterborne (WB) Zn-rich primers and high performance WB epoxy primers have been developed based on novel Cashew Nutshell Liquid (CNSL)-derived curing agents for industrial and protective coating applications. These unique WB phenalkamines were synthesized from a natural, non food chain and renewable biomaterial and could help formulate WB primer systems that meet stricter volatile organic compound (VOC) regulations as well as high performance requirerments. This article presents the latest performance studies of new phenalkamine-based WB Zn-rich primers and epoxy primers, and discusses the challenges associated with such formulations. New 2K WB Zn-rich primers were formulated with a water-free phenalkamine curing agent. The study results showed the WB Zn-rich primers had good compatibility with various commercially available solid epoxy dispersions and delivered good cure and mechanical properties ; importantly, those WB Zn-rich primers provided superb adhesion to both metal substrates and commercial polyurethane (PU) topcoats without the use of adhesion promoters. Excellent corrosion protection and good resistance to undercutting of the scribe were observed after 3000-h Q-Fog exposure. Additionally, newly developed WB high performance primers based on zero-VOC WB phenalkamines were evaluated either in combination with WB Zn-rich primers or by being directly applied over metal substrates was found that those WB epoxy primers could enhance corrosion protection as mid-coats to WB Zn-rich primers ; when being used direct-to-metal, WB epoxy primers also exhibited good mechanical and adhesion properties that benefited the overall anticorrosion performances. Note de contenu : - Part I : Waterborne (WB) Zn-rich primer study - Part II : Waterborne (WB) mid-coat systems based on new WB-C curing agent - Part III : Wet-on-wet properties - FIGURES : 1. Cashew apple and nutshell - 2. Average cardanol structure - 3. Example of phenalkamine structure - 4. Panel images of cross-hatch adhesion tests - 5. Panel images after 120h salt spray exposure - 6. Panel images after 4000-h salt spray exposure - 7. Panel images after 1200-h salt spray exposure - 8. Panel images after 2400-h salt spray exposure (surface rusts were removed via scratch pad) - 9. Panel images after 2300-h salt spray exposure (WB Zn-rich primer systems topcoated with a red iron oxide mid-coat) - 10. Panel images after scribe and wet adhesion testing - 11. Mixing viscosity changes as a function of the percentage of added water - 12. Linear dry time of various systems based on WB-C - 13. Panel images of resin 1+WB-C clear coating-system after 1200-h salt spray exposure - 14. Panel images of MC#1 and MC#2 systems after 271 and 767-h salt spray exposure - 15. Panel image of WB Zn-rich#4 primer system topcoated with MC#2 mid-coat primer after 1685-h salt spray exposure - 16. Photo images of the panels after wet-on-wet adhesion tests - TABLES : 1. Waterborne curing agents : typical properties - 2. Typical properties of solid epoxy dispersion resins - 3. WB Zn-rich primer formulations by using WB-A curing agent - 4. Mechanical properties of WB Zn-Rich primers - 5. WB mid-coat formulations based on WB-C - 6. Adhesion and anticorrosion performances of MC#2 systems as a function of mixing times - 7. Mechanical and adhesion properties of MC#2 - 8. Gloss comparison En ligne : https://drive.google.com/file/d/1QsQ8l4uOx13cFvlKXZElv8uh5js2daAr/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=30518 [article]

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