[article]
| 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 |
in COATINGS TECH > Vol. 17, N° 5 (05/2020) . - p. 18-27
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Novel cashew nutshell liquid-based waterborne curing agents designed for high-performance and low-VOC protective epoxy coatings in COATINGS TECH, Vol. 17, N° 5 (05/2020)
