Application of Barium Sulfate in Paints and Coatings

Physical and chemical properties of barium sulfate: barium sulfate is a white or off-white crystalline powder. It is an important barium-containing mineral with strong chemical inertness, good stability, acid and alkali resistance, high density, moderate hardness, high specific gravity and high whiteness. , can absorb harmful rays (X-rays and Y-rays) and other advantages. It has the luster of glass, non-magnetic and non-toxic. And materials with environmental protection functions are widely used in various coatings, medium and high-grade inks, rubber, papermaking, ceramics, cosmetics and other fields. Refined barium sulfate is also used in medium and high-grade paints, engineering plastics (household appliances, building materials plastics), high-grade insulating rubber, rubber products, cathode expansion rods of batteries, and glaze materials for ceramics and enamels.

Precipitated barium sulfate is used as filler, brightener and weighting agent in rubber, plastic, paper, paint, ink, coating and other industries. Barium sulfate is used to decorate the interior and exterior walls, which can effectively shield X-rays and Y-rays, and can effectively prevent the leakage of blocking rays.

The effect of barium sulfate on titanium dioxide and pigments in plastic gaskets can reduce the amount of pigment added and save about 10% of the cost.

Applying barium sulfate (about 25%) to the surface of PP is similar to ABS, and does not affect the existing characteristics of PPV, providing gloss and high hardness surface.

Barium sulfate can reach a filling rate of 80% of its weight. It can effectively isolate noise and noise when used in drainage pipes, speakers, and speakers. Barium sulfate can be used in curtains to increase the weight. It can improve the gloss, good hue, surface scratch resistance and good size stability when used in the housing of household appliances.

Barium sulfate is used as an extender pigment in coatings, which plays an important role in improving the thickness, wear resistance, water resistance, heat resistance, surface hardness, and impact resistance of the coating. In addition, barium sulfate has high reflectivity in the wavelength range of 300-400 microns, which can protect the paint film from light aging, and is an effective and inexpensive white inorganic light stabilizer. Because of its low oil absorption and high filling content, it can reduce the cost of coatings and can be used for water-based coatings, primers, intermediate paint coatings, oil-based coatings, etc. It is used to replace 10%-25% of titanium dioxide in water-based paints, and the result is that the whiteness increases and the covering rate does not decrease.

Paints and high-build coatings: Barium sulfate has high filling and can be applied to all coating series, such as primers, high-build coatings, etc. All types of its specific surface area and particle size division and easy flowability make barium sulfate in the processing process. With low abrasion in medium, barium sulfate is recommended for autopriming surface layers and maintains good uniformity and smoothness even at high fills.

Topcoat: Barium sulfate is superior to most other fillers, especially in chemical resistance coatings, its inertness, insoluble in water, acid, alkali and organic intermediates, excellent gloss and particle fineness make the topcoat in For protection from long-term exposure, barium sulfate is recommended for topcoats, which increase surface hardness and color stability.

Latex paint: due to weight reasons, barium sulfate can only be used in latex paint, mainly for high gloss and silk paint, and it is called "acid-resistant" latex paint, and it is resistant to acid even when exposed, and the easy dispersibility of barium sulfate Optical rotation and easy retention can increase its chemical properties, barium sulfate can be used in the same high-gloss paint and latex paint.

Wood products and paints: Barium sulfate has the characteristics of low cohesion, low light dispersion and fine particle retention, and is especially suitable for pigment topcoats, varnishes, spray paints, etc. According to research, barium sulfate has chemical resistance and weather resistance.

Powder coating: In powder coating, barium sulfate can improve its gloss, fluidity, filling and compatibility with various pigments.

The ultra-fine barium sulfate has a superior isolation effect on the particles of white or colored pigments, so that the particles of the pigment keep a certain distance from each other, and the efficiency of the pigment is improved. In particular, the barium sulfate particles are tiny and have excellent performance, which can free the reticular voids formed by titanium dioxide in inks and coatings, which greatly improves the weather resistance of inks and coatings and improves the quality of paints; and its impurities are very few and will not Impurities react chemically with organic substances in inks and paints; in addition, it has excellent dispersibility in all paints, which can prevent paint agglomeration, improve paint quality, and increase the effect of fluidity.

Adhesive: good rheology, filling and chemical resistance, making barium sulfate suitable for adhesives, unsaturated polyester and polyurethane systems.

Elastomers, sealing bodies: Barium sulfate is especially suitable for elastomers. It does not contain any heavy metal pollution or rubber gas, so it is especially suitable for food and medicine, and can provide its stability and anti-aging properties.

Thermoset: Barium sulfate is inert, color stable, combined with other pigments for better gloss, mechanical performance and low abrasion.

Thermoplastics: thermal conductivity and easy flow can reduce the injection molding time, and barium sulfate can be used as a nucleating agent to improve its strength and thermal stability.

Pigment: Light reflection maintains the full color of the pigment.

Using the above functions, it can replace part of the titanium dioxide without affecting the quality of the paint

1. Replace titanium dioxide below 30%

(1) This application has been tested by dozens of ink and paint manufacturers, and the effect is obvious.

(2) cost saving;

(3) Increase the weather resistance of the paint film;

(4) Improve paint quality and improve fluidity.

2. After replacing less than 30% of titanium dioxide, it will not affect

(1) Hiding power

(2) Glossiness

(3) Haze

The specific application areas are as follows:

Precipitated barium sulfate can be used as a supplementary filler and is widely used in various coatings, plastics, rubber, paints, inks, insulating tapes, ceramics, batteries, enamels and other industries. Can be used for acid-resistant rubber products and general products. It can also be used as surface coating agent, sizing agent, weighting agent, etc.

Plastics industry - Precipitated barium sulfate is used as a gasket for titanium dioxide and pigments in plastics, which can reduce the amount of pigments added and save about 10% of the cost.

Rubber industry - The application of precipitated barium sulfate (about 25%) to PP can make the surface of PP resemble ABS without affecting the existing characteristics of PP, and provide a surface with high gloss and high hardness. Precipitated barium sulfate can reach a filling rate of 80% of its weight. It can effectively isolate noise and noise when used in drainage pipes, speakers and speakers. Precipitated barium sulfate N can be used in curtains to increase the weight. It can provide high gloss, good hue, scratch resistance and good dimensional stability when used in the housing of household appliances.

Topcoat industry--precipitated barium sulfate is superior to most other fillers, especially in chemical resistant coatings. It is inert, insoluble in water, acids, alkalis and organic mediators. Excellent gloss and particle fineness make Topcoats are protected from prolonged exposure. Precipitated barium sulfate is recommended for topcoats to increase surface hardness and stabilize color.

Printing Ink - Low abrasion, high gloss and color stability, low cohesion, combined with its easy flowability make barium sulfate suitable for high-quality printing inks, and precipitated barium sulfate is recommended for highly optically active oils.

Latex paint industry - due to weight reasons, precipitated barium sulfate can only be used in latex paint, mainly for high gloss and silk paint, and is called "acid-resistant" latex paint. It has acid resistance even when exposed. Precipitated sulfuric acid The easy dispersibility, optical retention and easy retention of barium can increase its chemical properties. Precipitated barium sulfate can be used in high-gloss paint and latex paint

Lacquers and High-Build Coatings - Precipitated barium sulfate has high filling properties and can be used in all coating series, such as primers, high-build coatings, etc. Precipitated barium sulfate has low abrasion properties during processing. Precipitated barium sulfate is recommended for automatic primer surface layers and maintains good uniformity and smoothness even at high fillings.

Wood products and paints - Precipitated barium sulfate has the characteristics of low cohesion, low light dispersion and fine particles, and is especially suitable for pigment topcoats, varnishes, spray paints, etc. According to research, precipitated barium sulfate has chemical resistance and weather resistance.

Precipitated barium sulfate with a particle size of approximately 0.7-0.8 μm is required for high solids gloss topcoats. Using a larger particle size will affect the surface gloss. Smaller particle grades require more base material due to their higher specific surface area, so high fill ratios and high solids are nearly impossible.

Precipitated barium sulfate with a particle size in the range of 0.7 μm deflocculates and separates the pigment, thus enabling the reduction of the amount of pigment to a very low value. Because the 0.7μm precipitated barium sulfate actually has no effect on the viscosity in a wide range, it can be formulated according to the highest proportion of precipitated barium sulfate in the given formula, and has no effect on the gloss. Thus, these precipitated barium sulfates offer a good opportunity to reduce VOC and formulation costs by replacing more expensive pigments.

In addition to white or bright colored paints, it is worth mentioning that white powdery precipitated barium sulfate can also be used in pure black paints without affecting the black color. This is related to the refractive index of precipitated barium sulfate, which is similar to that of commonly used resins, so that the precipitated barium sulfate incorporated into the system is not white but transparent. Therefore, no light gray is produced in carbon black coatings. Precipitated barium sulfate also reduces the VOC of black paints. The biggest effect here is that the oil absorption and specific surface area of carbon black and precipitated barium sulfate are very different. The effectiveness of carbon black is only slightly increased by deflocculation, and the replacement of large amounts of carbon black with precipitated barium sulfate reduces the overall binder requirement and viscosity, which in turn also reduces VOC.

Precipitated barium sulfate for powder coatings

Powder coatings are one of the fastest growing markets in the coatings industry. Due to the special properties of precipitated barium sulfate, low binder requirements and excellent dispersion, it is an indispensable component of powder coatings. The specific gravity of precipitated barium sulfate is as high as that of titanium dioxide, thus giving us the opportunity to formulate non-flying powder coating formulations, even when using fine powders. The mechanical properties of precipitated barium sulfate filled powder coatings in typical powder coating formulations are related to particle size (the finer the better).

Precipitated barium sulfate for waterborne coatings

Due to its chemical inertness and insolubility, precipitated barium sulfate is as suitable for use in waterborne coatings as for conventional coatings. The effect of micronized precipitated barium sulfate has been demonstrated, even in electrocoatings (electrophoretic coatings have very complex requirements in terms of particle deposition conditions or wettability). Usually the replacement amount for titanium dioxide is in the range of 10-30%.