Comparison of the advantages and disadvantages of several coloring pigments
(1) White pigment
White pigments include titanium dioxide, lithopone, zinc white and antimony white. Hollow polymer microspheres are also good white pigments.
1. Titanium dioxide (TiO2)
A kind of most widely used white pigment, it is characterized by high whiteness, good coloring and covering power, excellent chemical stability, heat resistance and weather resistance. It can be divided into rutile type and anatase type.
1) Rutile (refractive index 2.76) has good weather resistance and no pulverization, which is suitable for outdoor coatings.
2) Anatase (refractive index 2.55) is inferior to rutile in stability, weatherability and pulverization, so it is suitable for indoor coatings.
2. Lithopone (lithopone, baso4zns)
Chemical property: alkali resistant, but decomposes in acid, releasing H2S.
Strong covering power, easy to darken when exposed to light, poor weather resistance.
3. Zinc white (ZnO)
Advantages: good light resistance, heat resistance, weather resistance, no powder, can be used for outdoor paint.
Disadvantages: poor covering power. Lithopone ＜ lithopone ＜ titanium dioxide. It is alkaline and tends to thicken after paint making.
There is a kind of ZnO containing Pb, which is a mixture of ZnO and basic PbSO4. It has better antirust performance than ZnO and can be used in primer.
Nano ZnO can kill bacteria.
1. Antimony white (Sb2O3)
Covering power is second only to titanium dioxide, white appearance, better chalking property than lithopone, good heat resistance, used in fireproof paint. T
