Application of precipitated barium sulfate in high temperature powder coatings
Barium sulfate is the main body pigment, accounting for 70% of the body pigment, other body pigments such as talcum powder, kaolin, mica powder, bentonite, quartz powder are mainly used as functional fillers. Therefore, the quality of barium sulfate selected directly determines the quality of powder coating. It has high reflectance in the range of 300-400um wavelength and can protect the paint film from light aging. It is an effective and cheap white matt stabilizer. Its needle-like crystal structure makes it a good leveling agent, and can increase the leveling property of the coating, can be used in self-cleaning coating as an enhancer; At the same time, because of the low oil absorption of barium sulfate, it has a high filling amount, so it can reduce the cost of coating.
First, the influence of particle size on the gloss of the coating
The finer the particle size of barium sulfate, the higher the gloss of the powder coating, and the highest gloss of the powder coating made by precipitation barium sulfate.
Two, plane powder coating coarse grain control
3. Control of heavy metal content
Barite is often accompanied by other heavy metal minerals, which contain different heavy metal ions. It is very important to choose the origin and manufacturer of barium sulfate. The products need to be tested for heavy metals, and the test results meet the requirements of RoSH directive.
Four, the use of barium sulfate in high temperature powder
Although barium sulfate has good thermal stability and weather resistance, its rhombic system changes easily at high temperature.
Precipitated barium sulfate is a kind of high-quality filler and constitution pigment, acid and alkali resistance, has excellent weather resistance, can be used for powder coating and high gloss PP engineering plastics filling. The composition of precipitated barium sulfate is BaSO4 and the crystal belongs to orthonormal sulfate mineral. They are usually thick plate-like or columnar crystals, and are often dense blocky or plate-like or granular aggregates. Quality pure colorless transparent, streaks white, glass luster, transparent to translucent. The three groups have complete cleavage, and the included Angle is equal to or nearly 90°. Mohs hardness is 3 to 3.5 and specific gravity is 4.0 to 4.6.
Fillers commonly used in powder coatings are precipitated barium sulfate, barite powder, light calcium carbonate, heavy calcium carbonate, kaolin, talcum powder, bentonite, precipitated silica, mica powder, quartz powder and silicon powder.
In powder coatings, precipitated barium sulfate can enhance the leveling and light retention of powder coatings, and has good compatibility with all colors. It can make the powder coating reach the ideal film thickness in the spraying process, and the powder rate is high.
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