(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. The mechanism is that antimony chloride reacts with chlorine containing Resin at high temperature to prevent fire spreading.
(2) Yellow pigment
1. Chrome Yellow (lead chrome yellow)
Its main component is PbCrO4 or PbCrO4 / xpbso4 mixed crystal. Due to different manufacturing conditions and compositions, the color is between lemon and orange.
Advantages: 1) good covering power and coloring power. With the increase of lead chromate content, the darker the color, the better the covering power. 2) It does not pulverize in the atmosphere.
Disadvantages: 1) under the action of light, the color will darken. 2) When exposed to H2S, it will react with PBS, black and toxic. 3) In case of alkali, it will change into orange chrome yellow, so it is not suitable to be shared with basic pigments. 4) It should be noted that lead compounds can accelerate the drying of dry oil.
2. Iron Oxide yellow (iron yellow, fe2o3h2o)
Good covering power, strong coloring power, light and alkali resistance. It is widely used in building materials.
3. Cadmium yellow (CDS)
The color is very bright, light resistant, heat-resistant, alkali resistant.
Disadvantages: 1) acid resistant; 2) easily powdered when exposed to moisture; 3) hiding power and coloring power are not as good as chrome yellow; 4) expensive.
It is suitable for making high temperature resistant coatings.
(3) Green pigment
1. Chrome oxide green (Cr2O3)
Features: insoluble in acid and alkali, resistant to SO2, H2S gas erosion. Good light and weather resistance, heat resistance, temperature resistance up to 700 ℃.
Disadvantages: the covering power is poor, the coloring power is worse, and it is not used much in the coating.
Suitable for chemical atmosphere and acid fog resistant coatings. High temperature paint, such as enamel.
2. Chrome Green [PbCrO4 · xpbso4 · yfenh4fe (CN) 6]
It is made of chrome yellow and iron blue. Good covering power and strong coloring power. Alkali resistant. It is widely used.
(4) Blue pigment
1. Iron blue [mxfey [Fe (CN) 6] 2 · nH2O, where M represents potassium or ammonium.
Features: strong coloring power, good light resistance and acid resistance.
Disadvantages: poor covering power, poor alkali resistance, not suitable for use with basic pigments. Hard texture, not easy to grind, surface treatment can improve the dispersion of grinding. Oil is easy to cause spontaneous combustion, especially in the process of slurry mixing and grinding. It is not safe until all particles are moistened by oil.
2. Ultramarine (3na2o · 3Al2O3 · 6sio2 · 2nas)
Features: light resistant, heat-resistant, alkali resistant, can counteract the yellow phase in white paint and whiten.
Disadvantages: poor coloring power and covering power, easy to sink or float in the coating, so it is appropriate to make a separate color paste.
(5) Red pigment
1. Iron red (iron oxide red, Fe2O3)
Features: light, weather and chemical stability, low price.
It can be used for topcoat and primer in large quantity.
2. Cadmium red (3CDs · 2cdse)
Features: bright color, good coloring power, covering power, light resistance, weather resistance, heat resistance and sulfur resistance.
High price, only for high temperature resistant paint.
3. Molybdenum chrome red
Chemical composition: PbCrO4: 75 ~ 85%; PbMoO4: 10 ~ 15%; PbSO4: 3 ~ 10%
Characteristics: inorganic pigments are bright color, strong coloring power, good light resistance and heat resistance. It can be mixed with other Organic Pigments to obtain the red color of appropriate color.
(6) Black pigment
1. Carbon Black
Carbon black for coating is Pigment Carbon Black.
Features: high covering power, strong coloring power, the best light and weather resistant pigments, stable chemical properties, acid, alkali and high temperature resistance, so it is the most common black pigment.
2. Iron black (Fe3O4)
Features: strong coloring power, low covering power, stable to light and atmosphere, alkali resistance. It can enhance the mechanical strength of the coating film and has a certain anti rust ability. When the metal coating requires a certain mechanical strength, iron black can be used instead of carbon black.
(7) Metallic pigments
1. Aluminum powder (commonly known as silver powder)
1 ~ 2 μ m in thickness and 1 ~ 200 μ m in diameter.
Floating type: it has floatability after surface treatment. It can be arranged parallel to the surface in the film forming process, showing metallic luster and shielding effect. It is mainly used as the topcoat of anti-corrosion coatings.
Non floating type: high surface tension, can not float on the surface, but in the lower layer of the film can be parallel and directional arrangement, mainly used for metal flash paint.
2. Copper powder (commonly known as gold powder)
The flake powder made of zinc copper alloy can be made into gold powder of different colors with different proportion of zinc and copper, which is mainly used for decoration.
(8) Organic pigments
Advantages: complete color; bright color; strong coloring power.
Disadvantages: poor covering power.
