[article]
| Titre : |
The use of engineered silica to enhance coatings |
| Type de document : |
texte imprimé |
| Auteurs : |
Jim Reader, Auteur ; Maria Nargiello, Auteur |
| Année de publication : |
2020 |
| Article en page(s) : |
p. 36-45 |
| Note générale : |
Bibliogr. |
| Langues : |
Américain (ame) |
| Catégories : |
Anticorrosifs
Anticorrosion
Brillance (optique) -- Mesure
Charges (matériaux)
Déperlance
Dispersions et suspensions
Fluidisation
Formation de film
Imperméabilisation
Matériaux amorphes
Mouillabilité
Résistance à l'abrasion
Rhéologie
SiliceLa silice est la forme naturelle du dioxyde de silicium (SiO2) qui entre dans la composition de nombreux minéraux.
La silice existe à l'état libre sous différentes formes cristallines ou amorphes et à l'état combiné dans les silicates, les groupes SiO2 étant alors liés à d'autres atomes (Al : Aluminium, Fe : Fer, Mg : Magnésium, Ca : Calcium, Na : Sodium, K : Potassium...).
Les silicates sont les constituants principaux du manteau et de l'écorce terrestre. La silice libre est également très abondante dans la nature, sous forme de quartz, de calcédoine et de terre de diatomée. La silice représente 60,6 % de la masse de la croûte terrestre continentale.
Viscosité
|
| Index. décimale : |
667.9 Revêtements et enduits |
| Résumé : |
The field of coatings technology has utilized many forms of silica-based particles in the last 70 years. This large, varied class of fillers is generically broken into two categories of crystalline and amorphous morphology. With ongoing scrutiny and sensitivity in the coatings industry to move towards less hazards in the workplace, greater emphasis is placed on suitable amorphous technology to replace crystalline silica technology. Amorphous silica is highly adaptable and flexible to be modified in both powder and pre-dispersed forms, and numerous engineered types of technologies have been developed to provide functional solutions to many coatings problems.
Amorphous silica technology has been developed to address functionalities including: rheological control, suspension of pigments and fillers, and reinforcement of coatings film; to impart scratch resistance, hydrophobicity / anti-corrosion benefits, and oleophobicity; as a carrier of trace actives into coatings for homogenous distribution; for flow control, charge, and fluidization enhancement of powdered coatings; and gloss reduction of liquid systems. Particle technology and modification will be addressed along with performance attributes highlighted for each of the types of tailor-made modifications. The importance of proper dispersion and homogenous distribution within a coating matrix will be reviewed.
This article will address how amorphous silica technology is differentiated and engineered to create specially tailored solutions to enhance the performance of coatings and will highlight the latest technical developments in this field. |
| Note de contenu : |
- Rheology and film formation
- Anti-corrosion/water repellency
- Scratch resistance
- Free flow, fluidization, transfer efficiency
- Gloss control
- Recent developments in silica technology
- Fig. 1 : The silica family tree
- Fig. 2 : Production of pyrogenic (fumed) silica
- Fig. 3 : Primary, secondary, and tertiary structures of fumed silicas
- Fig. 4 : Methanol wettability of differently treated fumed silicas
- Fig. 5 : Thickening efficiency of fumed silica as a function of surface treatment
- Fig. 6 : Improved film formation with fumed silica dispersions
- Fig. 7 : Improved corrosion resistance with hydrohobically treated fumed silica ; coatings based on published guide formulations from Halox
- Fig. 8 : Structure modification of fumed silica and scratch resistance
- Fig. 9 : Homogeneous distribution of silica through a polymer matrix
- Fig. 10 : Improved scratch resistance results in a high-soilds, 2K polyurethane clear coat based on Macrymal SM 510n60LG and Vestanat HB 2640MX
- Fig. 11 : Transfer efficiency and Faraday cage effects
- Fig. 12 : Fluidization efficiency
- Fig. 13 & 14 : Measuring gloss with a reflectometer (DIN EN ISO 2813)
- Fig. 15 : SEM images of a new spherical precipitated silica particles
- Fig. 16 : Viscosity "jump curves" for waterbased silica dispersions
- Table 1 : Comparison of characteristics of different synthetic silicas
- Table 2 : Common surface treatments for fumed silicas |
| En ligne : |
https://drive.google.com/file/d/17TVd7hca18xX6Tv0Yq4-_5oKHwAWTdO8/view?usp=share [...] |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34358 |
in COATINGS TECH > Vol. 17, N° 6 (06/2020) . - p. 36-45
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