What are the applications of precipitated 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 the spacers of pigments in plastics can reduce the amount of pigments 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.
The filling rate of barium sulfate can reach 80% of its weight. It can effectively isolate noise and noise when applied to drain pipes, speakers and speakers. Barium sulfate can increase the weight when applied to curtains. 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 coatings, barium sulfate can improve its gloss, fluidity, filling and compatibility with various pigments.
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.
Elastomer, sealing body: barium sulfate is especially suitable for elastomer, 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.
Thermosetting body: barium sulfate is inert, color stability, combined with other pigments to obtain better gloss, mechanical performance and low abrasion.
Thermoplastics: Thermal conductivity and easy fluidity 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 can maintain the complete 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) Covering power
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.
Plastic 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.
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.
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 about 0.7-0.8 μm is required for high solids glossy finishes. 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 can deflocculate and separate the pigment, thereby reducing 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.
Besides white or bright colored paints, it is worth mentioning that white powdered 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 big 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 water-based coatings
Due to the chemical inertness and insolubility of precipitated barium sulfate, it 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%.
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