Precipitated silica (silicon dioxide), as a core reinforcing filler in the rubber industry, has achieved large-scale application in green tires, shoe soles, hoses, and conveyor belts. Its performance advantages and technological breakthroughs have profoundly reshaped the energy efficiency and environmental standards of rubber products.

Core Application Areas
Green Tire Tread: Precipitated silica replaces traditional carbon black, significantly reducing rolling resistance (by 20%–30%) and improving wet grip. It is a key material for achieving EU A-grade green tire certification. By 2025, China's new energy vehicle sales will reach 11.3 million units, driving the proportion of green tire production to 58.6%, and increasing the consumption of precipitated silica to 7.8 kg/tire.
Shoe Sole Manufacturing: It can completely replace carbon black in light-colored, translucent, and transparent shoe soles, offering excellent wear resistance, tensile strength, and tear strength, while avoiding black pollution. This is one of the largest consumption scenarios in the footwear industry.
Hoses and Conveyor Belts: Enhances fatigue resistance and puncture resistance, suitable for high-wear environments such as mines and ports.
Seals and Special Rubbers: Improves heat resistance, aging resistance, and electrical insulation, widely used in automotive, electronics, and medical device fields.
Mechanism of Action and Interface Reinforcement
The reinforcing effect of precipitated silica stems from its high specific surface area (100–400 m²/g) and surface silanol (Si-OH) active sites, which enhance the crosslinking density of rubber molecular chains through physical adsorption and chemical bonding. However, the hydrophilic surface is prone to aggregation, requiring the use of silane coupling agents for interface optimization:

Mainstream Coupling Agents: Si69 (bifunctional sulfide coupling agent), A151 (vinyltrimethoxysilane), etc., which cooperate with the rubber vulcanization system to construct a "precipitated silica-coupling agent-rubber" ternary network. Modification Processes: Dry method (gas phase method) and wet method (in-situ modification by precipitation) are used in parallel. The dry method is more suitable for high-end products but has higher costs; the wet method is less expensive and suitable for general-purpose products.
Key Technological Breakthroughs in the Past Five Years
Technology Direction | Core Progress | Industry Impact
High-Dispersion Silica | Nanoscale particle size control (5–20 nm), CV value ≤ 3.5% (internationally advanced level) | Solves the dilemma of "low rolling resistance leads to weak grip," improving the dynamic performance stability of tires.
Surface Graft Modification | Grafting of polymer brushes such as polycaprolactone (PCL) and polystyrene (PS) | Improves compatibility, reduces mixing energy consumption, and extends product lifespan.
Low-Carbon Production Process | Calcium carbide residue as a substitute for silicon source, closed-loop wastewater treatment, photovoltaic energy driven | China's silica carbon footprint reduced to 1.25 tCO₂e/t, still higher than the EU's 0.68 tCO₂e/t.
Functional Composites | Integration of silica with triboelectric nanogenerators, development of self-sensing tires | Achieves integrated tire pressure monitoring and energy harvesting, a cutting-edge research direction.
Industry Status and Challenges
Production Capacity Landscape: By 2025, China's total silica production capacity will reach 2.85 million tons/year, accounting for 57.2% of the global total, with East China, North China, and Southwest China accounting for over 84%; the CR5 concentration of companies such as Quecheng Co., Ltd. and Longxing Chemical reaches 44.6%.
High-End Bottleneck: The effective production capacity of high-dispersion silica is only 480,000 tons/year (16.8%), and there is a generational gap with international giants such as Evonik and Solvay in terms of batch stability, Na₂SO₄ residue control, and carbon footprint.
Demand-Driven Growth: The CAGR of high-dispersion silica demand is expected to reach 18.3% from 2026 to 2030, and the demand will exceed 1.1 million tons by 2030, mainly from new energy vehicles and high-end tire markets.
Technological Evolution Trends
Materials: The research and development of bio-based silica and green alternatives to silane coupling agents (such as ionic liquids) are accelerating. Manufacturing side: Digital mixing control and intelligent manufacturing systems improve batch consistency.
Application side: The potential of precipitated silica in emerging fields such as thermal conductive silicone grease for 5G base stations and biodegradable plastics is becoming apparent.