What is inorganic pigments and their classification?
Inorganic pigments are oxides of metals or metal salts，Inorganic pigments are divided into natural inorganic
pigments and artificial inorganic pigments, Natural mineral pigments are generally of low purity and dark color,
but they are inexpensive. The synthetic inorganic pigments have complete chromatogram, bright color, pure color
and strong covering power.
Inorganic pigments are sun-resistant, heat-resistant, weather-resistant, solvent-resistant and strong
covering power, but the chromatogram is not complete, the coloring power is low, the color brightness
is poor, and some metal salts and oxides are toxic.
Classification by color
It is mainly titanium dioxide, which can be divided into rutile type and anatase type according to its
crystal structure. Rutile has better weather resistance and is widely used outdoors.
The main variety is carbon black. The properties of carbon black for pigments are different from those
for rubber. The main quality indexes of pigment carbon black are blackness and color. Carbon black
not only has coloring properties, but also has excellent weather resistance and thermal oxidation resistance.
Red pigments in inorganic pigments are mainly iron oxide red. Iron oxide red is the most common iron
oxide pigments. It has good covering power and dyeing power, chemical resistance, color retention,
dispersibility and low price. Iron oxide red is used in the production of floor paint and ship paint.
Because of its remarkable rust-proof performance, it is also the main raw material for the production
of rust-proof paint and primer.
There are mainly lead chrome yellow (lead chromate), zinc chrome yellow (zinc chromate), cadmium yellow
(cadmium sulfide) and iron oxide yellow (hydrated iron oxide) and other varieties. Among them, lead chrome
yellow is the most widely used. It has strong covering power, bright color and easy to disperse, but it is easy
to darken under sunlight. The covering power and coloring power of zinc chrome yellow are worse than those
of lead chrome yellow, but the color is light and the light resistance is good. Cadmium yellow has good heat
resistance, light resistance and bright color, but its dyeing power and covering power are not as good as lead
chrome yellow, and its cost is higher, so its application is limited. Lead chrome yellow and cadmium yellow
contain heavy metals and can not be used for coloring children's toys, cultural and educational supplies and
food packaging. Iron yellow color is dark, but durability, dispersibility, covering power, heat resistance,
chemical resistance, alkali resistance are very good, and the price is low, so it is widely used in building
There are mainly two kinds of chromium oxide green and composite iron oxide green. Chromium oxide green
has good light resistance, heat resistance and chemical resistance, but its color is darker and its colouring and
covering power are poor.
There are mainly iron blue, cobalt blue, Ultramarine blue and other varieties. Among them, Ultramarine blue has
higher yield, alkali resistance, acid resistance, bright color and high temperature resistance. Iron blue is
acid-resistant and alkali-resistant. Its covering power and coloring power are higher than those of Ultramarine blue
and its durability is worse than that of Ultramarine blue. Since the introduction of phthalocyanine blue into the
market, its dyeing power is twice as high as iron blue, and other properties are good, so the consumption of
iron blue is decreasing year by year. Cobalt blue has high temperature resistance and good light resistance,
but its colouring power and covering power are slightly poor, and its price is high, so its use is limited.
Iron oxide brown