How to Produce High-Quality Silicone Sealant: Complete Guide
Silicone sealant is one of the most widely used adhesive products in the world — used in construction, automotive, electronics, and everyday household repairs. But producing high-quality silicone sealant is not as simple as mixing a few ingredients. In this guide, we'll walk you through the complete silicone sealant manufacturing process.
1. What Is Silicone Sealant?
Silicone sealant is a one-part (or two-part) elastomeric sealant that cures when exposed to moisture in the air. It's known for excellent weather resistance, temperature resistance, and adhesion to many surfaces.
Temperature Resistant
-50°C to +150°C
Weather Resistant
10-20+ year lifespan
Strong Adhesion
Glass, metal, ceramic
Waterproof
Excellent water resistance
2. Key Raw Materials
| Ingredient | Function | Typical % |
|---|---|---|
| 107 Silicone Oil (Base Polymer) | Main film-forming polymer | 40-60% |
| Active Calcium Carbonate | Filler, reinforcement | 20-40% |
| Crosslinker (Methyl Trimethoxysilane) | Cures with moisture | 3-8% |
| Catalyst (DBTDL) | Speeds up cure reaction | 0.1-0.5% |
| Plasticizer (Dimethyl Silicone Oil) | Adjusts hardness/viscosity | 5-15% |
3. Manufacturing Process
Pre-treatment of Filler
Calcium carbonate must be dried at 100-120°C for 4-6 hours to remove all moisture. Any water in the filler will react with the crosslinker too early, ruining the product.
Loading Base Polymer and Filler
Load the 107 silicone oil and dried calcium carbonate into a vacuum double planetary mixer. Start mixing at low speed.
Heating and Mixing Under Vacuum
Heat the mixture to 120-140°C while maintaining full vacuum (-0.09 MPa). Mix for 2-3 hours. This step removes all remaining moisture and ensures complete dispersion of the filler.
Cooling Down
Cool the mixture down to below 40°C while still under vacuum. This is critical — you must NOT add the crosslinker while the mixture is hot, or it will cure immediately.
Adding Crosslinker and Catalyst
Once cooled to below 40°C, add the crosslinker (methyl trimethoxysilane) and mix for 10-15 minutes under vacuum. Then add the catalyst (DBTDL) and mix for another 10 minutes.
Packaging Under Vacuum
The final product must be packaged immediately — into cartridges, sausages, or drums — using vacuum packaging equipment. Any air contact will start the curing process.
4. Essential Equipment
Double Planetary Mixer
The heart of sealant production. Vacuum, heating, high-viscosity mixing.
Filler Dryer
Dries calcium carbonate to remove all moisture.
Cartridge Filling Machine
Fills cartridges and sausages under vacuum.
Conclusion
Producing high-quality silicone sealant is all about three things: complete moisture removal, strict vacuum conditions, and accurate formulation. Get these three right, and you'll have a product that lasts 12+ months on the shelf and performs perfectly for 10+ years in the field.
If you're planning to start sealant production, contact our engineers — we've helped dozens of customers set up complete sealant production lines.
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