As a high-performance composite material, silica gel is widely used in electronics, medical, automotive and other fields. The optimization of its production process needs to be promoted in multiple dimensions such as raw material selection, preparation process, post-processing and equipment improvement to achieve the dual goals of performance improvement and cost reduction.

1. Raw material selection and pretreatment optimization
Silica gel selection
Specific surface area control: The use of fumed silica with a high specific surface area (200-500 m²/g) can significantly improve the mechanical properties and thermal stability of silica gel.
Particle size distribution optimization: Multi-stage dispersion technology is used to ensure the uniformity of silica particle size (D50 is controlled at 5-15 μm) and reduce agglomeration.
Surface modification: Silane coupling agent (such as KH-550) is used to treat the surface of silica to enhance its compatibility with the silica gel matrix.
Optimization of silicone matrix
Selection of high viscosity silicone oil: Use methyl vinyl silicone rubber (VMQ) as the matrix, and its molecular weight (500,000-800,000) and vinyl content (0.1%-0.3%) need to be precisely controlled to balance processability and mechanical properties.
Filler compounding: Adding a small amount of calcium carbonate (<5 phr) as an incremental filler can reduce costs and improve the processing fluidity of silicone.

2. Preparation process optimization
Improvement of mixing process
Segment mixing method: Pre-mix silica with part of silicone oil for 10-15 minutes, then add silica matrix for secondary mixing, and control the total mixing time to 30-40 minutes to avoid excessive shearing leading to molecular chain breakage.
Temperature control: The mixing temperature is strictly controlled at 120-140℃ to prevent silicone cross-linking or silica dehydroxylation.
Optimization of molding process
Compression molding: adopt segmented pressurization process, first low pressure (5-10 MPa) exhaust for 1-2 minutes, then high pressure (20-30 MPa) vulcanization, vulcanization temperature 160-180℃, time 10-15 minutes.
Injection molding: optimize screw speed (50-80 rpm) and injection pressure (80-120 MPa) to reduce bubbles and flow mark defects.

3. Optimization of post-processing process
Secondary vulcanization
Secondary vulcanization at 200-220℃ for 2-4 hours can completely eliminate volatiles and improve the heat resistance and compression permanent deformation properties of silicone.
Surface treatment
Use plasma treatment or chemical plating technology to introduce hydrophobic groups on the surface of silicone to reduce surface energy and improve antifouling and wear resistance.

4. Integrated optimization of equipment and process
Internal mixer transformation
Use a dual-rotor continuous internal mixer with a temperature closed-loop control system to achieve a mixing temperature fluctuation of ≤±2℃ to ensure product consistency.
Online detection technology
Introducing the near infrared spectroscopy (NIR) online monitoring system, real-time feedback on mixing uniformity and filler dispersion, and timely adjustment of process parameters.

5. Environmental protection and cost optimization
Solvent recovery
Condensation and recovery of volatile silicone oil in the mixing process, the recovery rate can reach more than 90%, reducing raw material consumption.
Energy consumption management
The waste heat recovery system is used to use the waste heat of sulfide exhaust gas for raw material preheating, saving about 15%-20% energy.

6. Performance verification and case
Mechanical properties: After optimization, the tensile strength of silicone can reach 8-12 MPa, the elongation at break is 400%-600%, and the tear strength is 30-50 kN/m.
Thermal stability: The temperature of thermal weight loss 5% is ≥350℃, and the long-term use temperature can reach 200℃.
Application case: The silicone seals produced by a certain company using this process have a service life of more than 5 years in the engine compartment of a car, and the failure rate is reduced to less than 0.5%.
Through the above process optimization, the comprehensive performance of white carbon black silica gel is significantly improved, while the production cost is reduced by 10%-15%, and the market competitiveness is greatly enhanced.