Aug . 28, 2025 11:46
The coating industry is constantly striving for higher performance benchmarks, seeking enhanced adhesion, superior corrosion resistance, and extended service life to satisfy the requirements of industrial protective coatings (for steel structures, pipelines) and architectural coatings (for exterior walls, floors). Bentonite powder, a versatile additive, has emerged as a pivotal raw material in coating formulations, thanks to its remarkable thixotropy, excellent suspension stability, and seamless compatibility with resins. The montmorillonite within bentonite powder can form a "card-house" structure in the coating system, effectively preventing the sedimentation of pigments and fillers. Simultaneously, it penetrates into the micro-pores of the substrate, significantly enhancing the adhesion between the coating film and the substrate, thereby elevating the overall performance of the coating.
In the realm of industrial protective coatings, particularly anti-corrosion coatings utilized in marine, petrochemical, and bridge steel structures, bentonite powder plays an indispensable role in augmenting corrosion resistance. Marine steel structures are constantly exposed to harsh conditions such as salt spray, high humidity, and fluctuating temperatures. Ordinary anti-corrosion coatings typically start to peel off or rust within 2-3 years under these circumstances. However, when 2%-5% of bentonite powder is incorporated into epoxy anti-corrosion coatings, the montmorillonite in the powder forms a dense barrier layer within the coating film. This layer acts as a formidable shield, blocking the penetration of water, oxygen, and chloride ions. A marine engineering company in Shandong Province applied anti-corrosion coatings with our bentonite powder to offshore platforms. After 5 years of operation, the coating film remained in excellent condition, showing no signs of significant rust or peeling. In contrast, platforms coated with ordinary materials required repainting after just 2 years. Salt spray tests (conducted in accordance with ASTM B117) reveal that coatings containing bentonite powder can withstand 1000-1500 hours of salt spray without corrosion, which is 2-3 times the duration of ordinary coatings. Moreover, bentonite powder significantly improves the impact resistance and flexibility of the coating film. The impact strength can reach up to 50 kg·cm, and the film can pass the 1 mm mandrel test during the flexibility (bending test), effectively reducing the risk of coating cracking due to structural deformation.
For architectural coatings, including acrylic exterior wall coatings and polyurethane floor coatings, bentonite powder primarily functions as a thickener and suspension agent. Acrylic exterior wall coatings often encounter issues such as pigment sedimentation during storage, leading to uneven color, and poor workability, with inconsistent viscosity. By adding 0.5%-2% of bentonite powder, these problems can be effectively resolved. The thixotropic property of bentonite powder endows the coating with high viscosity when at rest, preventing sedimentation, and low viscosity during application, facilitating brushing or spraying and boosting construction efficiency. A coating manufacturer in Guangdong Province added 1% bentonite powder to its acrylic exterior wall coating, resulting in an extension of the coating's storage stability from 6 months to 12 months, with no pigment sedimentation observed. Additionally, the coverage rate of the coating increased by 15%, rising from 8 m²/kg to 9.2 m²/kg, thereby reducing the amount of coating required per unit area. In the case of polyurethane floor coatings, bentonite powder enhances the wear resistance of the coating film. Taber wear tests demonstrate that the weight loss of the coating film with bentonite powder is only 3-5 mg after 1000 rotations, which is 50% lower than that of ordinary floor coatings, making it an ideal choice for high-traffic areas like shopping malls and factories.
Our bentonite powder for the coating industry has two main types: water-based and solvent-based, to adapt to different coating systems. The water-based bentonite powder is modified with sodium polyacrylate, which has good dispersion in water-based coatings (such as acrylic, latex) and does not cause flocculation; the solvent-based bentonite powder is modified with organophilic surfactants (such as castor oil derivatives), which can be evenly dispersed in solvent-based coatings (such as epoxy, polyurethane) and improve the viscosity stability of the coating. The key technical indicators of our products are: montmorillonite content ≥85%, moisture content ≤8%, particle size 300-600 mesh, and thixotropy index (TI) ≥3.0 (measured at 6 rpm and 60 rpm). Each batch of products undergoes strict testing for compatibility with common resins (such as epoxy resin E-44, acrylic resin) and coating performance (adhesion, impact resistance), ensuring that it meets the needs of coating production. Special attention is paid to the montmorillonite content and its interaction with other components in the coating formulations.
Our technical team can help customers adjust the addition ratio of bentonite powder according to the type of coating and application scenario—for example, for high-gloss architectural coatings, we recommend using fine-grained bentonite powder (600 mesh) to avoid affecting the gloss of the coating film.
In terms of logistics, we can provide large packaging (1000 kg/bag) for large coating manufacturers to reduce packaging costs and improve handling efficiency. We also ensure that the products are delivered on time—for customers in Southeast Asia, the delivery cycle is 10-15 days; for customers in Europe and America, it is 20-25 days.
