[article]
| Titre : |
Oligourethane diol/melamine high solids : Baking schedules in terms of cure window |
| Type de document : |
texte imprimé |
| Auteurs : |
M. Yaseen, Auteur ; Syed Haseebuddin, Auteur ; K. V. S. N. Raju, Auteur |
| Année de publication : |
1997 |
| Article en page(s) : |
p. 482-486 |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Catégories : |
Haut extrait sec
MélamineLa mélamine, de nom chimique 1,3,5-triazine-2,4,6-triamine, est parfois dénommée cyanuramide ou cyanurotriamine. Sa formule brute est C3H6N6.
Les "résines mélamine-formaldéhyde" ou "mélamine-formol" (sigle MF) sont appelées "mélamine" dans le langage courant. Elles font partie de la famille des aminoplastes qui regroupe des résines thermodurcissables aminées, issues d'un comonomère tel l'urée ou la mélamine, parfois le thiocarbamide, le cyanamide hydrogène ou le dicyandiamide ; le second comonomère étant le formaldéhyde.
Oligomères
Polyuréthanes
Réticulation (polymérisation)
Revêtements organiques
|
| Index. décimale : |
667.9 Revêtements et enduits |
| Résumé : |
The cure behaviour of oligourethane diols crosslinked with melamine formaldehyde resin is influenced by the amount of the crosslinker used in the formulation and by the bake temperature. In the course of baking major part of the cross-linker is consumed in trans-etherification reaction and a part of it undergoes selfcondensation. The aromatic nature of TDI imparts rigidity while aliphatic IPDI results in flexibility of the backbone chain of oligomer. In the case of formulations containing 30% cross-linker baked at 140°C for 20 min, a major part of the reaction is completed which indicates the ideal condition for crosslinking. The findings indicate that the knowledge about the cure schedules is essential to control the poor durability, resistance to solvents, mar or scratch of underbake coatings as well as lack of flow and levelling, brush strokes, roller striations, orange peel, wrinkling and yellowing of overbake coatings. The profile of cure schedules has been determined in the form of Cure Window which measures the extent of reaction in terms of crosslink density as function of bake temperature. The width of the cure window has direct application to paint cure uniformity. The lower and upper range of temperatures for baking the coatings has been illustrated in terms of Nominal and True Cure Windows. |
| Note de contenu : |
- Cure Window
- Experimental : Oligourethane diol - Melamine crosslinker - Coating formulation - Preparation of free film of cured resin - Procedure for the determination of crosslinking density of cured resin
- Results : Construction of cure window - Nominal & true cure window |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=11404 |
in EUROPEAN COATINGS JOURNAL (ECJ) > N° 5/97 (05/1997) . - p. 482-486
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Oligourethane diol/melamine high solids in EUROPEAN COATINGS JOURNAL (ECJ), N° 5/97 (05/1997)
