| Titre : |
Two-component waterborne polyurethanes : The rheology of mixing |
| Type de document : |
texte imprimé |
| Auteurs : |
H. Bui, Auteur ; M. Dvorchak, Auteur ; K. Hudson, Auteur ; J. Hunter, Auteur |
| Année de publication : |
1997 |
| Article en page(s) : |
p. 476-481 |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Catégories : |
Bois -- Revêtements
Composés organiques volatils
Formulation (Génie chimique)
Mélanges (chimie)
Polyisocyanates
Polyols
Polyuréthanes
Revêtements bi-composant:Peinture bi-composant
Revêtements en phase aqueuse:Peinture en phase aqueuse
Rhéologie
|
| Index. décimale : |
667.9 Revêtements et enduits |
| Résumé : |
Two-component waterborne polyurethane systems for wood can be formulated with ultralow Volatile Organic Compounds (VOC) and Volatile Hazardous Air Pollutants (VHAPs). Due to the high surface tension of these systems, and the high viscosity of polyisocyanates relative to the polyol dispersion, problems still remain with mixing in industrial applications. The high viscosity causes gel formation in the in-line mixing apparatus, and the high surface tension and air entrapment cause microfoam in the final film. Therefore, the rheology of dynamic and static mixing of the system was studied in detail. The results show that the critical parameters for controlling the properties of the coatings are 1) viscosity of polyisocyanates and 2) particle size of the mixture of polyol and polyisocyanate under both low and high shear flow fields. With this knowledge, the spray equipment and formulation were modified for wood applications to give better spraying with no gel formation and reduced microfoam. |
| Note de contenu : |
- Chemistry of two-component waterborne polyurethanes
- Problems with two-component waterborne polyurethane coatings
- Materials
- Experimental
- Formulation for wood coatings applications
- Morphology of polyisocyanate and polyol latex in water
- Batch mixing
- Dynamic Mixing
- Modification of spray equipment
- Comparisons of mixing methods |
| Permalink : |
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in EUROPEAN COATINGS JOURNAL (ECJ) > N° 5/97 (05/1997) . - p. 476-481
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