Precipitated barium sulfate is used in high solid component coatings

2020/05/14 19:17

Precipitated Barium sulfate is used in high solid component coatings


Barium sulfate with a particle size of about 0.7-0.8μm is needed for high solid finish paint. The larger particle grade will affect the surface gloss, and the smaller particle grade will require more base material due to the higher specific surface area.


The Precipitated barium sulfate with particle size in the range of 0.7μm can resist flocculation and separate pigment, thus reducing the pigment amount to a very low value. Because 0.7μm of precipitated barium sulfate has no effect on viscosity over a wide range, it can be prepared in the highest proportion of precipitated barium sulfate in the formula given and has no effect on gloss. As a result, precipitated barium sulfate provides a good opportunity to reduce VOC, replace more expensive pigments, and reduce formulation costs.


In addition to white or bright colored coatings, it is worth mentioning that white powdery precipitated barium sulfate can also be used for pure black coatings without affecting the black. This is related to the refractive index of precipitated barium sulfate, which is similar to that of common resins. The precipitated barium sulfate doped system is not white but transparent. Therefore, light gray will not be produced in carbon black paint, and barium sulfate precipitation can also reduce the VOC of black paint. The oil absorption and specific surface area of carbon black and precipitated barium sulfate are very different. Through anti-flocculation, the effective effect of carbon black can only be slightly increased. Replacing a large amount of carbon black with precipitated barium sulfate will reduce the total base material demand and viscosity, and thus reduce VOC.


Precipitated barium sulfate is used in powder coatings


Powder coatings are one of the fastest growing markets in the coating industry. Barium sulfate precipitate is an indispensable component of powder coatings due to its special properties, low base material demand and excellent dispersion. The proportion of precipitated barium sulfate is as high as titanium dioxide, which provides us with the opportunity to prepare non-flying paint powder coating formulations. When using fine powder, the mechanical properties of precipitated barium sulfate filled powder coating in typical powder coating formulations are related to particle size (the finer the performance is, the better).


Precipitated barium sulfate is used in water-based coatings


Due to its chemical inertness and insolubility, precipitated barium sulfate is suitable for use in waterborne coatings as well as conventional coatings. The role of micropowders in precipitated barium sulfate has been demonstrated in electrophoretic coatings, where the requirements for particle deposition conditions or wettability are very complex. The usual amount of titanium dioxide replacement is in the range of 10-30%.


Precipitated barium sulfate is used in conductive coatings


Special inorganic treated grade precipitated barium sulfate can be used to prepare bright conductive coatings by giving conductive properties via the coating through the inorganic semiconductor, while other beneficial properties of precipitated barium sulfate remain unchanged. As with any other conventional conductive system, a certain fill ratio must be reached before the resistivity suddenly drops in order to create a conductive network. First, the resistivity of the circuit decreases by an order of magnitude, while the resistivity of the additional circuit decreases by a small amount. Permeability theory describes the behavior of these systems. Obviously, penetration points can vary over a wide range of fill ratios, and circuits can be formed by controlled flocculation, whereas long ago circuits were only formed by deposition. Once the solvent has successfully changed to a thermodynamically unsuitable solvent, then the use of organic additives is beneficial. Conductive coatings can combine with any other pigment or filler without loss of conductivity. When the raw material is finer than titanium dioxide, the addition of pigment increases the surface resistivity because the finer particles are stacked together, forming additional circuits.


Some possible uses and functions of non-black conductive coatings are summarized below:


Plastic coating - electrostatic spraying is allowed


Coil coating - for cleaning rooms


Printing ink - used for packaging of electronic components


Floor coating - prevent discharge


PET/PP films and foils -- obtain antistatic properties


Precipitated barium sulfate is used in automotive coatings


It is well known that precipitated barium sulfate can be used in all coatings of automotive coatings, just as precipitated barium sulfate can replace titanium dioxide in electrophoretic coatings. In addition, it can be used as a primer, because it is easy to disperse, but also has excellent weather resistance so it is also used as a topcoat. Settling barium sulfate stabilizes pigment and prevents flocculation, abrasion and excessive baking.


Because the ultrafine precipitated barium sulfate is extremely fine, they are completely transparent. Even in high fill, they can be used to increase the solid content of metal paint without causing color changes; It can also influence or control the leveling of the sheet metal.


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