| Titre : |
Determining rheological behaviour of paints, iks and coatings |
| Type de document : |
texte imprimé |
| Auteurs : |
Oliver Sack, Auteur ; Anton Paar, Auteur |
| Année de publication : |
2019 |
| Article en page(s) : |
p. 20-21 |
| Langues : |
Anglais (eng) |
| Catégories : |
Encre
Revêtements organiques
Revêtements:Peinture
Rhéologie
Rhéomètres
|
| Tags : |
Rhéomètre 'Expériences de rotation' oscillatoires' 'Balayage d'amplitude' 'Décomposition structurelle' 'Reprise structurelle''Test temps à 3 intervalles' |
| Index. décimale : |
667.9 Revêtements et enduits |
| Résumé : |
Understanding rheological properties of paints, inks and coatings is of great importance for many industrial applications, such as manufacturing, processing and curing/hardening.
Simple rotational experiments like shear stress-(CS) and shear rate (CR) controlled tests give only information about the viscosity value, the "seeming" yield point and the thixotropic effect. Since it is known for many years, that these values are not sufficient to describe the complex visco-elastic properties of paints, the use of more sensitive rheometers is recommended fora better understanding of the rheological characterisation. Modern air bearing-based rheometers provide the possibility to perform rotational tests, as well as oscillatory shear measurements. Measurements which are carried out under oscillatory shear conditions, provide advantages for characterising liquid and cured (film) paints and coatings. In addition, the curing or hardening process can be investigated and the glass transition point (Tg) can be determined. The most common used oscillatory experiments are the amplitude sweep (AS), frequency sweep (FS) and the structural recovery test (31TT). While the AS is used to determine the yield/flow point and the structural strength, the FS provides information about the sedimentation stability of the material. 31TT-tests are used to describe the levelling and sagging behaviour after the application process, as well as the thixotropic effect (time dependent structural recovery). Curing and hardening processes can not only be performed time and temperature controlled but also under UV exposure. For this reason, an air bearing-based rheometer is essential to avoid any shear influences to the 3-dimensional structures that corne up during the curing process. Compared to a viscometer, a modern rheometer system can be used fora full rheological characterisation of paints, inks and coatings.The generated data provide a deeper view inside the structure of the materials and help to understand and improve the manufacturing process and applicational problems. |
| Note de contenu : |
- Rotational experiments - state of the art
- Oscillatory experiments - modern methods
- Structural decomposition and regeneration
- Fig. 1 : Silver 3 (organoclay), silver 1 (acrylic thickener) and silver 3 (polyurethane thickener)
- Fig. 2 : Shows the viscosity curves of the three different paints. Over the shear rate range between 0.1 to 10005-1 the samples show much higher viscosity values compared to lower shear rates
- Fig. 3 : Amplitude sweeps of the three different silver coatings
- Fig. 4 : 3-Interval-Time-Tests (3ITT) of three different silver coatings |
| En ligne : |
https://drive.google.com/file/d/12NXSuASvepHIkB7w7qqmvK3o3ZKW9Sxy/view?usp=drive [...] |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=32917 |
in POLYMERS PAINT COLOUR JOURNAL - PPCJ > Vol. 209, N° 4654 (09/2019) . - p. 20-21
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