Silicon powder for powder coating

Silicon powder for powder coating

Silicon powder for powder coating is a kind of inorganic non-metallic functional filler with excellent properties. It is a kind of silica powder material which is processed by acid pickling, high purity water treatment, flotation, crushing, ball milling (or air jet milling) and other processes.

It has the characteristics of high purity (SiO2≥99%), uniform particle size distribution, high whiteness, high hardness, low water content, excellent acid and alkali corrosion resistance, good high temperature resistance, wear resistance, low linear expansion coefficient, good insulation coefficient, etc.

Silicon powder is widely used in silicone rubber, potting compounds, floor coatings, and powder coatings due to its excellent filling properties. Adding silicon powder enhances material surface hardness and scrub resistance, while partially replacing imported titanium dioxide to reduce costs. It is an indispensable functional filler in the electrical and electronic industries.

II. Partial Product Specifications:

3. Conventional physical properties of silicon micro-powder for powder coatings:

Silicon micropowder can be classified by the following characteristics and customized to meet customer requirements:

IV. Analysis of Silicon Micropowder Application in Coatings:

Silicon powder is a new type of functional green filler. It can improve the weather resistance, wear resistance and fire resistance of the paint film because of its unique chemical inertness and mineral properties.

1. Barrier effect. During the coating process, the paint film spreads out under the action of surface tension before curing, automatically forming a certain layer of silicon micro-powder coating, which serves as a protective layer;

2. Improve scrub resistance. The Mohs hardness of silicon micropowder is around 7, which can effectively enhance the hardness of the paint film after drying. Moreover, as an oxide powder, silicon micropowder contains partial hydroxyl groups on its surface, enabling better hydrogen bonding with the substrate or system, thereby improving scrub resistance.

3. Insulation. Silicon micropowder has high volume resistivity and no free ion impurities, which can effectively increase the surface resistance of the paint film and improve insulation.

4. Refractoriness. The component of silicon micro-powder is silicon dioxide. When added to organic silicon resin or organic silicon boron resin, it undergoes eutectic reaction at high temperature to form a new ceramic phase, thereby protecting the substrate.

5. New Material Silicon Micropowder Applications in Various Powder Coatings Industries:

Silicon micropowder is a high-purity, white powder derived from natural microcrystalline quartzite that has undergone prolonged weathering to form fine, dispersed particles. This material boasts excellent properties including high temperature resistance, acid/alkali corrosion resistance, good thermal conductivity, high insulation, low expansion, high hardness, and stable physicochemical characteristics. Widely used in industries such as chemicals, electronics, integrated circuits, electrical appliances, plastics, coatings, paints, and rubber, it serves as a versatile material in various applications.

1: Application in Heavy Anti-corrosion Powder Coatings

Silicon powder is an important component in heavy-duty powder coating. It plays an important role in the anticorrosion performance of powder coating. It can be filled into the structure of coating and form a dense and strong coating film, which can play a role in chemical passivation and physical sealing.

Generally, from the perspective of corrosion resistance, the more anticorrosive pigments and fillers are used, the better. However, this approach poses certain challenges in manufacturing and cost, such as increased melt viscosity of the coating, which hinders extrusion and leveling. Additionally, the coating film may become brittle over time. The optimal solution is to use neutral powder coatings with specialized silicon micro-powder fillers in a mixed application.

The chemical resistance of phenolic modified epoxy and silicon powder makes the performance of heavy-duty powder coating meet the standard SY/T 0315-2005.

2: Application in Flame Retardant Powder Coatings

Currently, the primary type of flame-retardant powder coating is epoxy powder coating. This is typically achieved by adding flame retardants (additive type) or introducing flame-retardant functional groups into the polymer chains of the resin matrix (reaction type), combined with heat-resistant pigments, fillers, and other components. The selection of fillers plays a crucial role in enhancing the flame-retardant performance of powder coatings. Among these, silicon micro-powder exhibits the highest heat resistance, making it the preferred filler for flame-retardant powder coatings.

3: Application in High Temperature Resistant Powder Coatings

The formulation of high-temperature resistant powder coatings involves two key approaches: leveraging the thermal stability of silicone resins and utilizing the heat resistance of specialized silicon micropowder. These coatings cannot meet high-temperature requirements with single resins or fillers alone. Silicon micropowder and talc fillers form the structural backbone of heat-resistant coatings, significantly enhancing their performance.

4: Application in Insulation Type Powder Coatings

The technical specifications for insulating powder coatings are highly stringent, with moisture resistance, flame retardancy, and breakdown voltage being achieved through the thermal stability and density of the silica micropowder used in these coatings.

5: Application in Epoxy Building Structural Adhesives

Taking epoxy construction structural adhesive as an example, when using specialized silicon micropowder for epoxy construction structural adhesive, the viscosity of the adhesive solution is significantly lower than that of ordinary angular silicon micropowder at the same dosage. Conversely, achieving the same viscosity requires a substantially higher dosage of silicon micropowder. This indicates that silicon micropowder with a special structure exhibits superior compatibility (filling properties) in epoxy steel bonding adhesive systems compared to ordinary silicon micropowder with irregular angular shapes. Consequently, this enhances the application scope of epoxy construction structural adhesive while also reducing production costs.

In terms of mechanical properties of architectural structural adhesives, epoxy-based silicon micropowder exhibits significantly higher shear and tensile strengths compared to conventional angular silicon micropowder when used in equal proportions, while compressive strength remains relatively stable. This is attributed to the superior compaction and reduced internal defects in epoxy adhesives, which minimize stress loss and enhance bonding strength. Furthermore, the quasi-spherical morphology of silicon micropowder lowers viscosity and improves wettability in epoxy steel adhesives, thereby optimizing adhesive performance.

6: Application in Interior Wall Latex Paint

Compared with traditional architectural coatings, the composite interior wall coatings with added silicon micropowder can significantly improve the stain resistance, thixotropy, scrub resistance, water resistance, alkali resistance and aging resistance of interior latex paint. The improvement of coating performance is most obvious when the mesh size of silicon micropowder used in interior latex paint is 800 mesh and the mass fraction is 3%-4%.

VI. Analysis of the Role of Silicon Micro-powder in Powder Coatings:

In the coatings industry, silicon micropowder's characteristics—including particle size, whiteness, hardness, suspension capability, dispersibility, low oil absorption rate, and high resistivity—significantly enhance coatings' corrosion resistance, wear resistance, insulation properties, and high-temperature performance. Due to its excellent stability, silicon micropowder has long been a crucial component in coatings as a filler. The material's primary functions are as follows:

1、Silicon powder has the properties of reinforcing, hydrophilicity, thickening, matting and anti-adhesion, because of its small particle size and large specific surface area.

2、can improve the wear resistance and scrub resistance of architectural coatings, enhance the adhesion of coatings and other properties;

3、Silica powder can replace other pigments and fillers in coatings, which not only reduces the cost of coatings but also has little change in the performance of coatings.

4、Barrier effect: When the filler is arranged in parallel in the film, the penetration of water and other corrosive substances is strongly blocked. With high quality silicon powder, the penetration time of water and other corrosive substances is generally extended by 3 times.

5. Improving the physical and mechanical properties of the paint film: The use of silicon micropowder can enhance a series of physical and mechanical properties of the paint film. The key lies in the morphological characteristics of the fillers, specifically the aspect ratio of granular fillers and the length-to-diameter ratio of fibrous fillers. Granular fillers act like sand and gravel in concrete, serving as reinforcement for the steel bars.

6. Enhancing the wear resistance of the paint film: The inherent hardness of resins is limited, and many fillers (e.g., talc) also exhibit low strength. In contrast, silicon micropowder, as a component of granite, possesses high hardness and mechanical strength. Therefore, its use as a filler significantly improves wear resistance.

7、Insulation Properties: Silicon micropowder possesses exceptionally high electrical resistance, inherently functioning as an insulating material. When combined with silicone resins or borosilicate resins to form composites, it transforms into thermally stable ceramic compounds with superior mechanical strength and insulation performance under high temperatures. Consequently, electrical wires and cables manufactured from these insulating materials maintain their original insulation integrity even after fire damage. This makes them particularly crucial for applications in mines, tunnels, specialized buildings, and critical infrastructure systems.

8. Thermal Radiation and High-Temperature Coatings: Silicon micropowder exhibits excellent infrared radiation properties. When combined with iron oxide, it can produce outstanding thermal radiation effects.

In the coating industry, the characteristics of silicon micropowder such as particle size, whiteness, hardness, suspension, dispersion, low oil absorption rate, high resistivity can improve the corrosion resistance, wear resistance, insulation, high temperature performance of coatings. Silicon micropowder used in coatings has been playing an important role in coatings fillers because of its good stability.

VII. Advantages of Product Application and Methodological Recommendations

1. For indoor/outdoor powder coatings, the additive amount is 5-20% of the formula based on hardness and cost requirements. Generally, adding 10% can achieve a hardness of 3H, while adding 20% can reach hardness above 4H. Moreover, the addition enhances the impact resistance and ductility of the paint film.

2. The product outperforms commercial alumina-based wear-resistant powders and wax-based scratch-resistant agents in hardness, wear resistance, and scratch resistance. Its superior leveling properties deliver a wax-like finish, and when combined with an appropriate amount of wax powder, it achieves optimal results.

3、Although the product is hard, the particle size distribution and particle morphology are well controlled, so the wear of the extruder is less, and it can be added to the extruder.

VIII. Application of Silicon Micro-powder in Coatings

Silica micro-powder, a non-toxic, odorless, and pollution-free inorganic non-metallic material, is produced through advanced ultra-fine grinding of pure quartz powder. Its fine particle size, high hardness, excellent suspension and dispersion properties, low oil absorption, and high resistivity make it widely used in the coatings and paints industry. With stricter environmental policies, rising raw material costs, and China's abundant quartz resources, the application of silica micro-powder in coatings holds promising market prospects and vast development potential.

(1) Silicon micropowder has good stability and has been playing an important role in coating filler. In the coating industry, the characteristics of silicon micropowder such as particle size, whiteness, hardness, suspension, dispersion, low oil absorption rate, high resistivity can improve the corrosion resistance, wear resistance, insulation, high temperature performance of coatings.

(2) Silica micro-powder serves as a functional filler in coatings to enhance volume and reduce production costs. As a shielding and matting agent, quartz (silica) can partially replace expensive titanium dioxide in coatings and paints, lowering manufacturing expenses. In flame-retardant insulating coatings, the addition of silica micro-powder improves thixotropic properties, resulting in uniform coating coverage, crack resistance, shorter curing time, and cost efficiency.

(3) Silicon micropowder is non-toxic, odorless, and environmentally friendly, containing no organic pollutants and featuring low metal content. It enhances the coating's UV resistance while delivering excellent thermal insulation. By incorporating silicon micropowder into epoxy resin, researchers have developed a non-toxic epoxy toughening coating with anti-corrosion properties, effectively addressing the limitations of conventional coatings in low-temperature brushing and spraying applications.

(4) With short grinding time, strong adhesion, and rapid drying, this additive (6-15% by weight) is used in formulating varnishes, primers, and rust-proof paints. It not only serves as a filler and volume enhancer but also significantly improves paint fineness, leveling performance, and film hardness. Additionally, it reduces grinding time, enhances water resistance, rust-proofing, and anti-corrosion properties, improves pigment dispersion, and increases storage stability.