The pigment is a very important component in the production and use of coatings. The types and colors of pigments can show different physical properties according to their chemical structure.
1、White pigments
Titanium dioxide (titanium white) TiO2, zinc oxide (zinc white) ZnO, Lidl powder (zinc barium white) ZnS-BaSO4, zinc sulfide ZnS, antimony white Sb2O3
According to the different crystal types, titanium dioxide is divided into rutile and anatase. Rutile titanium dioxide has good stability and is widely used in the coating industry. Anatase is easy to chalk, mainly used in paper and chemical fiber.
2、Red pigment
Cadmium red NCDs-CdSe, iron red Fe2O3, toluidine red (pigment scarlet)
3、Yellow pigment
Cadmium yellow CdS-BaSO4, iron yellow Fe2O3-H2O, lead-chromium yellow xPbCrO4-yPbSO4
Light-resistant yellow G (Hansa yellow G), benzidine yellow
4、Green pigment
Chromium oxide green Cr2O3, chromium green PbCrO4-xPbSO4-yFeNH4[(CN)6]
5、Blue pigment
Iron blue KxFy[F(CN)6]x-nH2O, ultramarine(NH4)xFey[Fe(CN)6]z-nH2O, phthalocyanine blue NaxAlySizOiSj
6、Black pigment
Carbon black, iron oxide black(FeO)x-(Fe2O3)y
7、Metal pigment
Aluminum powder Al, zinc powder Zn, gold powder CuxZny
8、Systematic pigments
Calcium carbonate CaCO3, barium sulfate BaSO4, talcum powder 3MgO-4SiO2-H2O, kaolin Al2O3-2SiO2-2H2O, wollastonite CaSiO3, mica powder K2O-3Al2O3-6SiO2-2H2O
The main function of paint is to protect and decorate. The components in the dry film are the main film-forming substances and pigments, and the function of the paint film is realized by these.
The ratio of the volume occupied by the main film-forming substances and pigments in the dry film has an important influence on the performance of the paint film. The percentage of the volume occupied by the pigment in the dry film is called the pigment volume concentration and is expressed as PVC (pigment volume concentration).
PVC = pigment volume / total volume of the paint film
When the PVC increases to a certain point, the polymer resin fills the voids formed by the tight accumulation of pigments. When the pigment absorbs the resin and fills the space between the pigment volume concentration, the PVC is called critical PVC and is expressed as CPVC.
