[article]
| Titre : |
Improving resin colors |
| Type de document : |
texte imprimé |
| Auteurs : |
Dieter Guhl, Auteur |
| Année de publication : |
2012 |
| Article en page(s) : |
p. 65-67 |
| Langues : |
Anglais (eng) |
| Catégories : |
Polyalkydes
Polycondensation
Polyesters
Polymères -- Coloration
|
| Index. décimale : |
667.9 Revêtements et enduits |
| Résumé : |
Polycondensation resins, like alkyd- and polyester resins require high reaction temperatures during the manufacturing process. Temperatures usually significantly above 200°C are necessary for well known reasons : they help to drive out the reaction water, to achieve the desired molecular weight and to lower the overall reaction time. Further on in the case of alkyd resins high temperatures induces some polymerization reactions, which influence the viscosity of the resin positively.
But there are not only positive effects for the application of high reaction temperatures. Besides the energy costs the color of the resin is influenced. Not very surprisingly resin manufacturers note, that with high temperatures and long reaction times the color values of the resins increase. Resin customers prefer binders as lightly colored as possible to achieve full flexibility for the coloristic options in the finished paint.
The thermally induced color development of the condensation resins is dependent on several factors :
- quality of the raw material, especially of the nature-based oils and fatty acids,
- proper control of the cooking process
- the catalyst
- use of antioxidants
The color formation is chemically caused by different reactions as for example :
- dehydration reaction
- oxidation reaction
- formation of olefins, aldehyds or ethers,
- elimination reactions with formation of conjugated double bonds
- polymerization reactions |
| Note de contenu : |
- Quality of the raw materials
- Proper control of the cooking process
- Catalyst influence
- Use of antioxidants
- Table 1 : Color development of different oleic acid types after esterification at 200°C
- Table 2 : Catalysts for resins
- Table 3 : Color development in dependency of oil length
- Table 4 : Catalyst/antioxidant combinations and their effect on reaction time and color
- Table 5 : Resin composition for TIB AOA study
- Table 6 : Results for antioxicants |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=16261 |
in PAINTINDIA > Vol. LXII, N° 9 (09/2012) . - p. 65-67
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Improving resin colors in PAINTINDIA, Vol. LXII, N° 9 (09/2012)
