Calcium carbonate is a non-toxic, odorless, non-irritating white powder, and it is one of the most widely used inorganic fillers. Calcium carbonate is neutral, basically insoluble in water, soluble in acid. According to different production methods of calcium carbonate, calcium carbonate can be divided into heavy calcium carbonate, light calcium carbonate, colloidal calcium carbonate and crystalline calcium carbonate. Calcium carbonate is a common substance on the earth. It exists in aragonite, calcite, chalk, limestone, marble, travertine and other rocks. It is also the main component of animal bones or shells. Calcium carbonate is an important building material and is widely used in industry.
Application of Calcium Carbonate in Latex Paint
1. The role of heavy calcium
(1) As an extender pigment, it has a filling effect, making it fine, uniform and high in whiteness.
(2) It has a certain dry covering power. Generally, ultra-fine products are used. When the particle size is close to that of titanium dioxide, the covering effect of titanium dioxide can be improved.
(3) It can improve the strength, water resistance, dryness and scrub resistance of the paint film.
(4) Improve color retention.
(5) Reduce the cost, the usage is 10%~50%. Disadvantages: high density, easy to precipitate, the amount of use should not be too large.
2. The role of light calcium
(1) As an extender pigment, it has a filling effect, is delicate, and increases whiteness.
(2) Has a certain dry hiding power.
(3) The density is small, the specific surface area is large, and it has a certain suspension property, which plays an anti-settling effect.
(4) Reduce costs.
(5) Increase the feel. Disadvantages: easy to white frost, swell, thicken, the dosage should not be too large, can not be used in exterior wall paint.
Application of Calcium Carbonate in Powder Coatings
(1) It can be used as a filler for high-gloss paint products.
(2) Semi-gloss coating products can generally be prepared by adding calcium carbonate directly, without adding matting agent, which saves cost.
(3) Inorganic pigments that are white in nature can be used in conjunction with titanium dioxide to reduce costs.
(4) Compared with other fillers, calcium carbonate is most suitable for some environmentally friendly products that require low heavy metal content, such as children’s toys, baby carriages, etc.
(5) It can increase the coating powder rate and spraying area, especially when it is used in mixed powder.
(6) If outdoor weather resistance is required, it cannot be used as a filler.
(7) Because of its high oil absorption, it is easy to cause orange peel on the surface of the paint film. At this time, a little hydrogenated castor oil can be added to the base material.
(8) It acts as a skeleton, which can increase the thickness of the paint film and improve the wear resistance and durability of the coating.
Application of Calcium Carbonate in Wood Coatings
(1) Used as a filler for colored primers to reduce costs.
(2) Increase the strength of the paint film and make it wear-resistant.
(3) Light calcium has a little thickening effect, is easy to thixotropy, and has good anti-sedimentation property.
(4) Heavy calcium reduces the sandability in the paint film, and is easy to precipitate in the tank, so attention should be paid to strengthening the anti-settling property.
(5) Improve the gloss, dryness and whitening of the paint film.
(6) It should not be used together with alkali-resistant pigments and fillers.
Application of Calcium Carbonate in Automobile Paint
Ultrafine calcium carbonate with a particle size of less than 80nm is used in anti-stone chip coatings and topcoats for automobile chassis due to its good thixotropy, with a market capacity of 7000~8000t/a.
Application of Calcium Carbonate in Ink
Ultrafine calcium carbonate is used in ink, showing excellent dispersion, transparency, excellent gloss and hiding power, as well as excellent ink adsorption and drying properties. It must be activated and its crystal form is spherical or cubic.