Precipitated barium sulphate as a standard product has been widely used in various industries: coatings, plastics, rubber, adhesives, inks, etc. One of the most common is to fill coatings to enhance their mechanical properties. Coatings are divided into various types according to their segment characteristics, and how does precipitated barium sulphate work in different coating systems? Read the blog to learn more about the principles involved.
For High-solid Coatings
For high-solid glossy topcoats, precipitated barium sulphate with a particle size of approximately 0.7-0.8 μm is required. Using a larger particle size will affect the surface gloss. Smaller particle size requires the use of more base material due to the higher specific surface area. Therefore, high filler ratios and high solid content are almost impossible.
Precipitated barium sulphate with a particle size of 0.7μm is able to prevent flocculation and separate pigments, thus can reduce the pigment amount to a very low level. The 0.7 μm precipitated barium sulphate actually has no effect on viscosity over a wide adding range, so in the given formula can add higher ratios of precipitated barium sulphate and the gloss won’t be influenced. Thus, precipitated barium sulphate offers a good opportunity to reduce VOC and reduce the cost of the formula due to its substitution of more expensive pigments.
In addition to white or bright-colored coatings, it is worth mentioning that white precipitated barium sulphate powder can also be used in pure black coatings without affecting the black color. This is because the precipitated barium has a similar refractive index to the commonly used resin, so the precipitated barium sulphate mixed into the system is not white but transparent. Thus, carbon black coatings will not turn grey.
Precipitated barium sulphate can also reduce the VOC of black coatings. There is a big difference in oil absorption and specific surface area between carbon black and precipitated barium sulphate. By anti-flocculation, precipitated barium sulphate can replace a large amount of carbon black to reduce the total base material amount and also reduce viscosity, which in turn effectively reduces the VOC.
For Powder Coatings
Powder coatings are one of the fast-growing markets in the coatings industry. As precipitated barium sulphate has special properties, low base material requirements, and excellent dispersion, it has become an indispensable component of powder coatings. The specific gravity of precipitated barium sulphate is as high as that of titanium dioxide, thus providing the opportunity to make powder coatings without overspray even when using ultrafine powders. In typical powder coating formula, the mechanical properties of the finish are influenced by the particle size of precipitated barium sulphate. The smaller the particle size, the better the properties.
For Waterborne Coatings
Due to its chemical inertness and insolubility, precipitated barium sulphate is as suitable for waterborne coatings as conventional coatings. It has been proven that even in electrophoretic coatings (its requirements in terms of particle deposition or wettability are very complex), the micronized precipitated barium sulphate can also work effectively. The usual substitution of precipitated barium sulphate for titanium dioxide is in the range of 10-30%.
For Conductive Coatings
Specialized precipitated barium sulphate of inorganic treatment grade can be used to make bright conductive coatings. The conductive properties via the coating are given by the inorganic semiconductor, while the other beneficial properties of the precipitated barium sulphate remain unchanged.
As with any other conventional conductive system, a certain fill ratio must be achieved before the resistivity drops abruptly in order to create a conductive network. First of all, the circuit resistivity drops by orders of magnitude, while the additional circuit resistivity drops minutely. The permeation point can vary over a wide range of fill ratios and by controlled flocculation is able to form circuits, whereas long ago circuits were formed by mere overslaking. Once the solvent has been successfully turned into a thermodynamically unsuitable solvent, then the use of organic additives is beneficial.
It goes without saying that conductive coatings can be combined with any other pigment or filler without conductivity loss. When the raw material is smaller than titanium dioxide, the addition of pigments increases the surface resistivity because the tiny particles are stacked together, forming an additional circuit.
Some of the possible uses and functions of non-black conductive coatings are listed below:
- Plastic coatings– allows for electrostatic spraying
- Coil coatings– for clean rooms
- Printing inks — for electronic components packaging
- Floor coatings –prevents discharge
- PET/PP films and foils –obtain antistatic properties
For Automotive Coatings
It is well known that precipitated barium sulphate can be used in all coating films of automotive coatings. Just as precipitated barium sulphate can replace some of the titanium dioxide in electrophoretic coatings, it can also be used in primers and topcoats because of its excellent dispersion and weather resistance. Precipitated barium sulphate stabilizes the pigment and prevents flocculation, abrasion, and excessive baking.
Due to the tiny particle size of ultrafine grade precipitated barium sulphate, they are completely transparent even at high filling levels. Therefore, they can be used to increase the solids content of metallic paints without causing color changes. They can also improve the leveling of metal flakes.
Hoyonn Precipitated Barium Sulphate
Due to its superfine particle size, chemical inertness, and good transparency, precipitated barium sulphate has been used by coating manufacturers across the world to fill various coatings to reduce material overall costs and improve mechanical properties. Although it is a national standard product, Hoyonn Precipitated Barium Sulphate (HY-PBS) has better particle size distribution, higher whiteness, and lower oil absorption. In addition to the various coatings mentioned above, precipitated barium sulfate can also be used in plastic, rubber, friction materials and more polymer industries.
Related reading: A Complete Guide To Precipitated Barium Sulphate
Learn detailed technical index of our precipitated barium sulphate on the product page, or contact us for the best price in your location. We always provide professional advice according to your industry and are happy to customize formulas for your special needs.