Aesthetic properties of coatings from water-dispersion paints

Abstract

The article contains the results of research of water-dispersion paints mineral fillers and pigments influence on coatings whiteness and yellowness. Aesthetic properties of coatings were evaluated according to the degree of filling of water-dispersion paints with carbonates (30, 40, 50, 60, 65 and 70 wt. %) and with kaolins (30, 40, 50 and 60 wt. %). The whiteness was calculated by Berger formula, yellowness index was calculated according to ASTM E313. Data of tri-stimulus color coordinates was obtained on a spectrophotometer Techkon SP 820λ (illuminant D65, observation 10o).
It has been identified that whiteness increased and yellowness decreased with enhancement degree of coatings filling. Coatings from water-dispersion paints with carbonate have higher whiteness than with kaolin. When the content of natural chalk MMC-1 of Novgorod-Siverskyi Plant of Buildings Materials increases from 30 to 70 wt. % the coatings whiteness increases for more than 35 units from 11.5 to 48.4, and yellowness index reduces for almost 17 units. When filling with chalk MMC-2 of Sloviansk Chalk-Lime Plant the increase of coatings whiteness is smaller by 10 units and yellowness index smaller by 5 units.
Coatings based on chemically precipitated chalk have a significantly higher whiteness (83.3 at 70 wt. % filling) and lower yellowness (4.5), due to its higher whiteness in the initial state (93 %). When using chemically precipitated chalk rise of coatings whiteness not so strongly depends on degree of filling increase, unlike natural chalk and kaolin.
Coatings from water-dispersion paints based on kaolin Prosianivskyi mark KC-1 have higher whiteness and lower yellowness compared with coatings based on kaolin Glukhovetskyi KC-1, which can be explained by higher whiteness and dispersion of first mentioned in the initial state.
The most significant growth of coatings whiteness is observed at 60–70 wt. % content of carbonates and 50–60 wt. % content of kaolin, which can be explained by increased light scattering due to maximum packing density of the filler particles in the coating.
Significantly improve the aesthetic properties of coatings based on water-dispersion paints allows adding of 2.5 wt. % TiO2 pigment, representing 35 units during the application of chalk MMC-1 of Novgorod-Siversk and 33 units with kaolin Prosianivskyi mark KC-1. The increase of TiO2 content up to 5 wt. % the coatings whiteness based on natural chalk increase by 10 units and based on kaolin prosianivskyi and glukhovetskyi by 14 and 15 units accordingly. Further increase of pigment content per 2.5 wt. % does not significantly affect on increase of coatings whiteness. Maximum coatings whiteness at 10 % TiO2 content was 65 units in mixed with carbonate filler MMC-1 mark, and with kaolin Prosianivskyi and Glukhovetskyi – 52 and 44 units accordingly.
Adding the fillers with high whiteness (chemically precipitated chalk, wollastonite) mixed with natural fillers (kaolin, chalk) into water-dispersion paints allow only marginally increase the aesthetic properties of coatings.
These data obtained allow us to adjust the aesthetic properties of coatings with water-dispersion paints in a wide range by varying the content of mineral fillers, adding TiO2 pigment, fillers with high whiteness while providing high performance characteristics of coatings.