[article]
| Titre : |
Pigment : measurement of performance |
| Type de document : |
texte imprimé |
| Auteurs : |
Juergen H. Braun, Auteur |
| Année de publication : |
1998 |
| Article en page(s) : |
p. 79-81 |
| Langues : |
Américain (ame) |
| Index. décimale : |
667.2 Colorants et pigments |
| Résumé : |
Successes in the development of tests for pigment characterization have contributed greatly to sucesses of the industry. However, problems with the evaluation of performance have slowed progress in some areas of pigment development. Characterization involves measurement of indentifiable surface, structure, etc. Performance evaluations involve systems: paints and paint films. Complexity of the systems contributes to testing problems.
Usually, performance tests try to simulate the real word. The closer to reality the test, the more convincing is its result. Test paints resemble, and often are, commercial paints. But commercial paints are formulated to minimize performance differences among ingredient batches or suppliers. The formulations are thus designed to be insensitive to the performance characteristics at stake.
Model paints can be formulated for sensitivity to pigment performance but paint are convincing but not sensitive to the pigment performance. Data from a model paint is sensitive to the pigment but not convincing.
Optical performance testing is least affected because of impressive instrumental progress. Hiding power, tinting strength and color can now be tested quantitatively , reliably, and reproducibly. Relative standard deviations of ± 5% are typical. Testing of durability, mechanical, and chemical performance has become a bottleneck to progress. Results can usually only be renked but not quantified and can rarely be reproduced to even modest satisfaction. Uncertainties, relative standard deviations, of 30-40% of value are typical. Problems are aggravated because the coatings industry overestimates the reliability and reproducibility of test results. Sill, it is not enough that a test reproduces well. In addition, it must be sensitive enough to reproduce small differences between similar pigment.
Statistical evaluation of performance data would certainly help. Statistical quality control saves future expense but costs up-front money. Appreciation of statistics and paint laboratories and has yet to make significant inroads into manufacture and management. |
| Note de contenu : |
- OPTICAL PERFORMANCE : Pigment strength
- DURABILITY : Color pigments - Coatings
- CHEMICAL AND MECHANICAL PERFORMANCE |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18005 |
in JOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 70, N° 880 (05/1998) . - p. 79-81
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Pigment : measurement of performance in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 70, N° 880 (05/1998)
