Fumed Silica for Silicone Rubber: How Highly Dispersible HL-150 Improves Performance
Highly Dispersible Fumed Silica HL-150 for Silicone Rubber: Improved Dispersion, Transparency, and Reinforcement
HIFULL® Highly Dispersible Fumed Silica HL-150 is an upgraded hydrophilic fumed silica developed from standard HL-150. Its particle structure and surface characteristics are optimized through controlled adjustment of surface silanol groups, active sites, and pore structure. The resulting material has a lower bulk density and combines high oil absorption, improved dispersibility, strong thickening performance, high light transmittance, and effective reinforcement. It is designed for silicone rubber and other organosilicon systems requiring consistent dispersion and processing performance.
Dispersion Performance
The number of dispersed particles provides a direct indication of filler dispersion uniformity within the silicone rubber compound. Standard HL-150 typically shows 5–7 dispersed particles, while Highly Dispersible HL-150 reduces the count to 2–3, representing a reduction of more than 50%.
This improvement is achieved by optimizing the surface treatment process and controlling the density and spatial distribution of silanol groups. Reduced hydrogen bonding between particles allows silica aggregates to break down more readily under shear during mixing. The particles can therefore distribute more uniformly throughout the silicone matrix, with fewer localized agglomerates.
Consistency and Thickening Performance
In this test system, a lower consistency value corresponds to higher viscosity and stronger thickening performance. In room-temperature silicone rubber, standard HL-150 has a consistency of 8.1–8.3, compared with 7.8–7.9 for Highly Dispersible HL-150.
More uniform filler dispersion promotes the formation of a denser and more effective three-dimensional network within the silicone matrix. As a result, Highly Dispersible HL-150 provides greater thickening efficiency at the same loading level, allowing formulators to achieve higher viscosity without increasing silica dosage.
Optical Performance
Light transmittance is particularly sensitive to filler dispersion in transparent silicone rubber systems. In room-temperature silicone rubber, standard HL-150 typically provides a light transmittance of 79%, while Highly Dispersible HL-150 reaches up to 83%.
Lower particle agglomeration reduces light scattering in the cured material. This allows the silicone rubber to maintain higher transparency at a given filler loading, making the Highly Dispersible HL-150 suitable for formulations that require both optical clarity and filler reinforcement.
Mechanical Reinforcement
At the same addition level, silicone rubber filled with Highly Dispersible HL-150 achieves a tensile strength of 1.0–1.2 MPa, compared with approximately 1.0 MPa for standard HL-150.
Uniformly dispersed fumed silica provides a greater number of effective physical interaction points within the silicone matrix. Improved filler–matrix interaction and more uniform stress distribution contribute to higher tensile strength and more consistent mechanical performance in the finished product.
Performance Comparison
Compared with standard HL-150, HIFULL® Highly Dispersible Fumed Silica HL-150 provides measurable improvements in filler dispersion, thickening efficiency, light transmittance, and mechanical reinforcement. The reduced number of dispersed particles from 5-7 to 2-3 corresponds with improved processing behavior and more uniform filler distribution throughout the silicone matrix.
These performance gains result from process optimization across particle nucleation, agglomeration control, pore-structure adjustment, and surface modification. Rather than relying on a single post-treatment step, the production process is designed to control the factors that affect silica dispersion throughout particle formation and subsequent processing.
HIFULL applies this process approach to the development of application-specific fumed silica grades for silicone-based formulations, including photovoltaic adhesives, electronic potting compounds, and transparent medical silicone rubber.
Silicone Rubber
Adhesives & Sealants
Resin
For manufacturers and formulators working with high-performance organosilicon systems, Highly Dispersible HL-150 provides a practical option where conventional fumed silica dispersion limits mixing efficiency, transparency, viscosity control, or mechanical performance. Its combination of improved dispersibility and reinforcement makes it suitable for silicone rubber systems requiring controlled rheology, consistent processing, high optical clarity, and reliable mechanical properties.
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ABOUT HIFULL
Our main products are fumed silica, nano titanium dioxide, and nano aluminium oxide. We get 20+ years of expertise and 40,000 tons of annual capacity. We supply total of 23 grades of hydrophilic & hydrophobic fumed silica. We have registrations for EU-REACH, Turkey-REACH, K-REACH and UK-REACH. We are the leading setting body for ISO18473-3:2018, ISO23157:2021 and ISO18473-4:2022. Learn More About Hifull
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My name is Van, I’m the business manager of HIFULL, I have been in Fumed Silica Industry for more than 10 years. Feel free to contact me. I’m happy to provide you the best service and products.
