| Titre : |
Crosslink density and cure window of oligourethane diol/melamine high-solids coatings |
| Type de document : |
texte imprimé |
| Auteurs : |
M. Yaseen, Auteur ; K. V. S. N. Raju, Auteur ; Syed Haseebuddin, Auteur |
| Année de publication : |
1998 |
| Article en page(s) : |
p. 35-42 |
| Note générale : |
Bibliogr. |
| Langues : |
Américain (ame) |
| Catégories : |
Formaldéhyde
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
Polyols
Polyuréthanes
Réticulation (polymérisation)
Revêtements
|
| Index. décimale : |
667.9 Revêtements et enduits |
| Résumé : |
Oligourethane diols were crosslinked with melamine formaldehyde, and their crosslink density was determined by using an equilibrium swelling method. In formulations containing primary or secondary hydroxylated diol the major part of the crosslinker is consumed by trans-etherification reactions and self-condensation. The aromatic nature of TDI imparts rigidity while the aliphatic IPDI results in flexibility of the backbone chain of oligomer. The profile of cure schedules has been determined in the form of a cure window which measures the extent of reaction in terms of crosslink density as a function of bake temperature. The experimentally determined properties like tensile strength and MEK rub-resistance have been taken into consideration for fixing the lower and upper limits of XLD in designing the cure windows of individual coating formulations. The baking schedules of coatings have also been expressed in the form of nominal and true cure windows. |
| Note de contenu : |
- INTRODUCTION : Crosslinking reactions between polyols and melamine - Crosslink density - Techniques for the determination of crosslink density - Curing aspects of high-solids coatings - Cure window
- EXPERIMENTAL : Oligourethane diol - Melamine crosslinker - Coating formulation - Preparation of free film of cured resin - Procedure for the determination of crosslink density - Calculation of crosslink density - Tensile properties - Solvent (MEK) rub resistance
- DISCUSSION : Effect of bake temperature and crosslinker content of XLD - Effect of oligourethane diol on crosslink density - Influence of isocyanates used in oligourethane diols - Cure schedules - Baking schedules in terms of cure window - Nominal and true cure window |
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in JOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 70, N° 879 (04/1998) . - p. 35-42
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Crosslink density and cure window of oligourethane diol/melamine high-solids coatings in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 70, N° 879 (04/1998)
