Fumed Silica for Class A Fire-Rated Glass

In the structure of Class A nano-silicon fire-rated glass, the intermediate nano-silicon fire-resistant gel interlayer is the core to achieve fire protection and thermal insulation. Many people focus on the glass sheet and overall structure, but easily overlook fumed silica, the key functional filler. Although its addition ratio is only 0.5% to 3.0%, it affects four dimensions at the same time: infusion process, light transmission appearance, high-temperature fire resistance and long-term weatherability.

Ordinary fumed silica is prone to agglomeration in silica sol systems. Achieving dispersion requires extensive grinding, which significantly increases slurry viscosity. Excessively high viscosity will cause difficulty in exhaust during vacuum infusion, leaving micro-bubbles in the gel layer and fog spots on the finished glass. High impurity content will precipitate under high temperature fire conditions, causing interlayer discoloration and local foaming defects. In severe cases, it will lead to excessive temperature on the unexposed side and fail the Class A type test.

The new domestic material ZLPSIL-MF Series fumed nano-silica is directionally developed to address the above industry shortcomings. Different from ordinary fumed silica, as a newly self-developed category, the product highlights two characteristics: low viscosity contribution and 47% high dispersibility. The silica purity is ≥99.999%, and all heavy metal impurities are controlled at ppm level. The high dispersion feature allows the powder to disperse uniformly in the nano-silicon fire-resistant sol, reducing agglomerated particles. Under the same dosage, the viscosity increase of the system is much lower than conventional grades. The slurry maintains excellent fluidity, facilitating factory vacuum infusion, reducing bubble defects and ensuring the transparent optical effect of fire-rated glass.

From the perspective of fire protection mechanism, after the glass on the fire-exposed side cracks in a fire, the nano-silicon fire-resistant interlayer containing the powder is heated, foamed and expanded. ZLPSIL-MF participates in the silicon phase sintering reaction, builds a continuous dense porous ceramic skeleton, reduces heat conduction, and helps the finished product meet both Class A fire resistance integrity and thermal insulation requirements. Industry conventional structure reference: 25mm triple-glass double-cavity achieves 1h fire resistance, 35mm four-glass triple-cavity achieves 1.5h fire resistance, 45mm four-glass triple-cavity achieves 2h fire resistance, 65mm seven-glass six-cavity achieves 3h fire resistance. The above durations are for industry reference only, and the final performance is subject to the complete glass type test report.

In addition to fire-rated glass interlayers, this material is also suitable for high-end industrial formulations that cannot accept significant viscosity increase, balancing anti-settling reinforcement without destroying system fluidity, connecting the two major tracks of building fire protection materials and fine chemicals.