Calcium carbonate is an important filler in paint production. Fineness and particle distribution determine paint transparency. Calcium carbonate has good weather resistance, wear resistance, and low electrolyte content. It provides pH stability, enhancing corrosion resistance and rheological properties. Calcium carbonate is also crucial in water-based coatings, improving quick-drying performance. It plays an important role in road marking applications.
Additionally, using calcium carbonate in paint can reduce the amount of titanium dioxide, which is economically beneficial. This will further stimulate the growth of calcium carbonates usage in coatings.
Calcium carbonate for latex paint
Calcium carbonate has a certain level of hiding power. In latex paints, ultrafine products are typically used, with a dosage of 10%-50%. When its particle size is similar to titanium dioxide, it improves the covering effect of titanium dioxide. This reduces latex paint costs, making it finer, more uniform, and with higher whiteness. It also enhances film strength, water resistance, drying, and scrub resistance.
For example, ultrafine calcium carbonate powder significantly reduces the dispersion and milling time in latex paint production. It improves hiding power, enhances latex viscosity, reduces titanium dioxide usage, and improves putty sanding performance.
When designing paint formulas, high-performance latex paints use ultrafine light calcium carbonate, while lower-grade paints use relatively coarse, low-oil-absorption heavy calcium carbonate.
Calcium carbonates for automotive paint
During vehicle operation, the underside of the car and wheel mudguards often encounter impacts and washouts from mud, gravel, and wastewater. As a result, the coating on the substrate surface is easily damaged, losing its corrosion resistance, causing the substrate to rust and eventually perforate.
To solve this problem, coatings with sand and stone impact resistance and corrosion protection should be applied to these areas. PVC plastisol is one type of automotive underbody paint, mainly composed of PVC paste resin, plasticizers, fillers (CaCO3), stabilizers, tackifiers, solvents, and other additives.
Calcium carbonate accounts for nearly 30% of the total composition (specific amounts depend on the formula), and the addition of nano-calcium carbonates significantly improves the system’s rheological properties and the film’s impact resistance compared to regular CaCO3. In automotive underbody coatings, the spray application process requires easy spraying, low viscosity, and good flowability, while after application, high viscosity is needed to prevent sagging and dripping.
This requires the coating to have low viscosity under high shear speeds for easy spraying and leveling, while maintaining high viscosity under low shear or static conditions to prevent sedimentation and dripping. This property is called thixotropy, and nano-calcium carbonates products meet this requirement in terms of application and structural performance.
Special features of nano-calcium carbonates for automotive underbody coatings: high activation degree and good thixotropy.
Calcium carbonate for ink
In printing inks, calcium carbonates mainly acts as a filler to reduce costs and increase volume. High-performance ultrafine calcium carbonate is usually required, with characteristics like fine particle size (0.02-1.0 μm), large surface area, high oil absorption, good transparency, brightness, and stability.
In practical applications, nano-light CaCO3 or nano-activated light calcium carbonate is the most suitable. However, nano-activated light calcium carbonate is expensive, so most ink production uses nano-light calcium carbonates.
Inks made with activated calcium carbonates have good body and viscosity, excellent printing performance, quick drying, and no side effects.
Due to its small particles, it exhibits excellent dispersibility, transparency, gloss, opacity, as well as excellent ink absorption and drying properties, making printed products fine and with complete dot structures. Especially after resin binders are widely used in inks, activated calcium carbonates, with its excellent stability, has almost replaced other fillers.
Currently, high-end ink fillers mainly use ultrafine calcium carbonates, which must be activated, with crystal forms being spherical or cubic.
Calcium Carbonates for Powder Coatings
Powder coatings commonly contain fillers with heavy metals, which do not meet international standards for heavy metal content. Especially for products exported to Europe and the United States, the requirements for heavy metal content are very strict. CaCO3 is an inexpensive white filler that does not contain heavy metals. It can completely replace the commonly used barium sulfate filler in powder coatings. Calcium carbonate is mainly used in the coating of products such as toys, baby strollers, sports equipment, kitchenware, and household appliances.
Advantages of calcium carbonate in powder coatings:
- It can be used as a filler in high-gloss coating products.
- For coating products, calcium carbonates can usually be directly added without the need for a flatting agent, saving costs.
- As a white inorganic pigment, it can be used in combination with titanium dioxide to reduce costs.
- Compared to other fillers, CaCO3 is most suitable for environmentally friendly products that require low heavy metal content, such as children’s toys and baby strollers.
- It can improve the powder coverage rate and spraying area, especially noticeable in mixed powders.
Ultrafine active calcium carbonate has high oil absorption and refractive index, and its low density can reduce the overall density of powder coatings, increasing the spraying area under the same filler amount. Additionally, due to calcium carbonate’s good electrostatic properties, it can enhance the powder coverage rate. Moreover, calcium carbonates can also improve the edge coverage, film hardness, and anti-caking properties of powder coatings.
conclusion
In conclusion, various types of calcium carbonate, including ultrafine light calcium carbonate, heavy calcium carbonate, and nano-calcium carbonate, are widely used in paint formulations. Each type offers specific benefits, such as improving opacity, enhancing durability, reducing costs, and ensuring environmental compliance. Choosing the right type depends on the desired properties of the paint, including its gloss, texture, and performance in different applications.
Epic powder
Epic Powder, 20+ years of work experience in the ultrafine powder industry. Actively promote the future development of ultra-fine powder, focusing on crushing,grinding,classifying and modification process of ultra-fine powder. Contact us for a free consultation and customized solutions! Our expert team is dedicated to providing high-quality products and services to maximize the value of your powder processing. Epic Powder—Your Trusted Powder Processing Expert !
