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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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Coatings world Vol. 24, N° 2 URL