Precipitated Silica for Silicone Rubber Applications
In the 1930s, PPG became one of the first companies to manufacture precipitated silica for use in base silicone rubber compounds and we have remained a leading industry supplier ever since.

Available in a variety of formulations, the quality, purity and proven performance of our precipitated silica products enables them to function as premium, value-focused alternatives to fumed silica in black, non-black, colored, and translucent silicone rubber compounds by incorporating the following mechanical properties:
- Excellent tensile-strength, tear-strength and flex-fatigue resistance
- Cost-effective reinforcing strength
- Reduced crepe hardening
- Outstanding compression-set resistance
- Exceptional resistance to heat-aging
Together, these properties have the potential to reduce costs and process inefficiencies for silicone rubber compounders by providing:
- More flexible inventory management through reduced shelf hardening
- Faster, more efficient mixing and re-milling of elastomers
- Less fly-loss-related product waste
Through our flagship PPG HI-SIL® silica product line, we offer a complete selection of specialized synthetic amorphous precipitated silica formulations that integrate physical properties such as particle size, surface area and pH levels according to the demands of both the compounder and the ultimate end-user.
Recommended Products and Typical Properties for Silicone Rubber Applications
Silica Product | N2 (BET-5) Surface Area (m2/g) |
pH | Residual Salt Type | Physical Form | Reinforcement |
---|---|---|---|---|---|
Hi-Sil 532EP | 55 | 8 | Na2SO4 | Powder | Semi-Reinforcing |
Hi-Sil 900 | 135 | 7 | Na2SO4 | Powder | Reinforcing |
Hi-Sil 233-D | 151 | 7 | Na2SO4 | Powder | Reinforcing |
Hi-Sil 135 | 150 | 7 | Na2SO4 | Powder | Reinforcing |
Hi-Sil 915 | 195 | 7 | Na2SO4 | Powder | High |
Hi-Sil is a registered trademark of PPG Industries Ohio, Inc.
Typical Applications
- Insulating wire covers
- Heat-resistant belts and hoses
- Flexible and elastic gaskets, seals and o-rings
- Touchpads and computer keypads
Related Resources

Carrier and Free-Flow
Our precipitated silica products are used as free-flow and carrying agents for food, animal feed and agricultural and industrial applications enabling products and processes to flow better.

Coatings, Adhesives and Sealants
Our precipitated silica products are used as high-performance flatting agents, thickening agents and anti-corrosion pigments to improve the performance, workability and sustainability of coatings, paints, inks, adhesives, and sealants.

Microporous
PPG's precipitated silica products are a key component of battery separators and TESLIN® synthetic paper, providing microporosity that is the basis for a wide range of related performance benefits.