Page 21 - Handbook of Surface Improvement and Modification

16 Scratch and Mar Resistance

2.2.3 HYDROTALCITE

GENERAL INFORMATION
Name: hydrotalcite CAS #: 11097-59-9 EC #: 234-319-3
Moisture, wt%: 0.35-0.5 Active ingredient, wt%: 99.6
Product composition: molar ratio MgO/Al O =4-5
3
2
PHYSICAL PROPERTIES
State: powder Odor: none Color: white
o
o
o
Cloud point, DACP, C: Cloud point, MMAP, C: Cloud point, ODM, C:
o
o
Decomposition temperature, C: 400 Melting point, C: 250
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3
Bulk density, kg/m : 0.3-0.5 Particle size, nm: 50 Density, kg/m : 2003-2009
Refractive index: 1.495-1.529 pH: 8-9.5
Polyurethane powder clear coating systems containing polyester resin, blocked polyisocy-
anate, and hydrotalcites intercalated with carbonate, aminododecanate, and ethylenedi-
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aminetetraacetate were examined. Modification of polyurethane powder coatings with
intercalated hydrotalcite improved surface properties, such as surface free energy, gloss,
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hardness, and scratch resistance. The modified coatings had higher roughness compared
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with the reference sample. The best combination of properties (better hydrophobicity,
hardness, and scratch resistance) was found for the coating modified with Zn, Al hydrotal-
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cite intercalated with hydrophobic aminolaurate anions (Figure 2.15).

Figure 2.15. Schematic structure of magnesium-aluminium hydro-
talcite intercalated with aminolauric acid. [Adapted, by permission,
from Pilch-Pitera, B; Kedzierski, M; Olejnik, E; Zapotoczny, S,
Prog. Org. Coat., 95, 120-6, 2016.]