Comparison of the advantages and disadvantages of several coloring pigments

White pigments include titanium dioxide, rhodolite, zinc white and antimony white. Hollow polymer microspheres are also good white pigments.

White pigments

White pigments include titanium dioxide, rhodolite, zinc white and antimony white. Hollow polymer microspheres are also good white pigments.

1. Titanium dioxide (TiO2)

One of the most widely used white pigments, characterized by high whiteness, good coloring and covering power, excellent chemical stability, heat resistance and weather resistance. It can be divided into rutile and anatase.

1) Rutile (refractive index 2.76) has good weather resistance, does not chalk, and is suitable for outdoor coatings.

(2) anatase (refractive index 2.55) is less stable, weathering and chalking than rutile, and is suitable for indoor coatings.

2. Rutile powder (Rutile powder, baso4zns)

Chemical properties: resistant to alkali, but decomposes when encountering acid and emits H2S.

Strong covering power, easy to turn black when exposed to light, poor weather resistance.

3. Zinc white (ZnO)

Advantages: good light resistance, heat resistance, weather resistance, no chalking, can be used for outdoor paint.

Disadvantage: poor covering power. Lidl powder＜Lidl powder＜Titanium dioxide. It is alkaline and will thicken after paint making.

There is a kind of ZnO containing Pb, which is a mixture of ZnO and alkaline PbSO4. It has better antirust properties than ZnO and can be used in primers.

Nano zinc oxide can kill bacteria.

4. Antimony white (Sb2O3)

Covering power is second only to titanium dioxide, white appearance, better chalking than Lidl powder, good heat resistance, used in fireproof paint. The mechanism is that antimony chloride reacts with chlorine-containing resin at high temperature to prevent the spread of fire.

Yellow pigment

1. bathroom cushion(lead chrome yellow)

Its main component is PbCrO4 or PbCrO4/xpbso4 mixed crystal. Due to different manufacturing conditions and composition, the color is between lemon and orange.

Advantages: 1) Good covering power and coloring power. As the content of PbCrO4 increases, the darker the color, the better the coverage. 2) No chalking in the atmosphere.

Disadvantages: 1) The color will become darker under the action of light. 2) It will react with PBS when it meets H2S and is black and toxic. 3) It will turn into orange-chrome yellow when it meets alkali and should not be shared with alkaline pigments. 4) It should be noted that lead compounds can accelerate the drying of dry oil.

2. Iron oxide yellow (iron yellow, fe2o3h2o) Covering power

Good, strong coloring power, light resistant and alkali resistant. It is widely used in construction materials.

3. Cadmium yellow (CDS)

Very bright color, resistant to light, heat and alkali.

Disadvantages: 1) Acid resistant; 2) Easily chalked when exposed to moisture; 3) Less covering power and coloring power than chrome yellow; 4) Expensive.

Suitable for making high temperature resistant paint.

Green pigment

1. Chrome oxide green (Cr2O3)

Characteristics: Insoluble in acid and alkali, resistant to SO2 and H2S gas erosion. Good light resistance and weather resistance, heat resistance, temperature resistance up to 700℃.

Disadvantages: poor covering power, poor coloring power, not much used in coatings.

Suitable for chemical atmosphere and acid mist resistant paints. High temperature paint, such as enamel.

2. Chrome green [PbCrO4-xpbso4-yfenh4fe(CN)6]

Made from chrome yellow and iron blue. Good covering power and strong coloring power. Resistant to alkali. It is widely used.

Blue pigment

1. iron blue [mxfey [Fe (CN) 6] 2 - nH2O, where M stands for potassium or ammonium.

Features: strong coloring power, good light and acid resistance.

Disadvantages: poor covering power, poor alkali resistance, not suitable for use with alkaline pigments. Hard texture, not easy to grind, surface treatment can improve the dispersibility of grinding. The oil is easy to cause spontaneous combustion, especially in the slurry mixing and grinding process. It is unsafe until all particles are wetted by oil.

2. Ultramarine (3na2o-3Al2O3-6sio2-2nas)

Characteristics: Light, heat and alkali resistant, can neutralize the yellow phase in white paint and whiten.

Disadvantage: poor coloring and covering power, easy to sink or float in the paint, it is appropriate to make color paste alone.

Red pigment

1. Iron red (iron oxide red, Fe2O3)

Characteristics: Light resistance, weather resistance and chemical stability, low price.

Can be used in large quantities for topcoats and primers.

2. Cadmium red (3CDs-2cdse)

Features: bright color, good coloring power, strong covering power, light resistance, weathering resistance, heat resistance, sulfur resistance.

High price, only for high temperature resistant coatings.

3. Molybdenum-chromium red

Chemical composition: PbCrO4: 75~85%; PbMoO4: 10~15%; PbSO4: 3~10%

Characteristics: Inorganic pigment with bright color, strong coloring power, good light and heat resistance. It can be mixed with other organic pigments to get the appropriate color of red.

Black pigment

1. Carbon black

Carbon black for paint is pigment carbon black.

Features: high covering power, strong coloring power, the best pigment for light and weather resistance, stable chemical performance, acid, alkali and high temperature resistance, it is the most common black pigment.

2. Iron black (Fe3O4)

Features: strong coloring power, low covering power, stable to light and atmosphere, alkali resistant. It can enhance the mechanical strength of the coating film and has a certain rustproof ability. When the metal coating needs certain mechanical strength, iron black can be used instead of carbon black.

Metal pigments

1. Aluminum powder (commonly known as silver powder)

The thickness is 1~2μm, and the diameter is 1~200μm.

Floating type: floating after surface treatment. In the film-forming process, it can be arranged parallel to the surface, showing metallic luster and shielding effect. Mainly used as the top coat of anti-corrosion coatings.

Not floating type: high surface tension, can not float on the surface, but in the lower layer of the paint film can be arranged in parallel orientation, mainly used for metal flash paint.

2. Copper powder (commonly known as gold powder)

Flake powder made of zinc-copper alloy, can be made into different colors of gold powder with different zinc-copper ratio, mainly used for decoration.

Organic pigment

Advantages: complete colors; bright color; strong coloring power.

Disadvantages: poor covering power.