High temperature resistant silicone sealant is a type of elastic sealing material based on polydimethylsiloxane, combined with heat-resistant fillers (such as fumed silica and ceramic powder) and specialized cross-linking systems. It can maintain sealing, adhesion, and elasticity in high temperature environments for a long time, while also being weather resistant, chemically resistant, and having strong electrical insulation properties.
Core classification and temperature resistance level
By curing type
Single component (neutral/acidic, room temperature moisture curing): neutral (oxime, alkoxy), non corrosive, suitable for metals and electronics; Acidic solidification is fast but has a vinegar like taste, which can corrode some metals.
Two component (addition/condensation curing): higher upper limit of high temperature resistance, suitable for industrial high temperature conditions.
Classified by temperature resistance
Medium temperature type: Long term temperature resistance of 200-260 ° C (ordinary industrial silicone);
High temperature type: long-term 260-315 ° C, instantaneous 350 ° C (phenyl modified silicone);
Ultra high temperature type: long-term 315-350 ° C, instantaneous 400 ° C+(special formula, such as ceramic filling).
Key performance characteristics
Wide temperature range tolerance: It can usually operate from -60 ° C to 300 ° C, and some models can reach up to 350 ° C;
Elasticity and displacement ability: After curing, it has good elasticity and can absorb the thermal expansion and contraction of the substrate;
Chemical stability: resistant to oil, water, ozone, ultraviolet radiation, and not easily aged;
Excellent electrical insulation properties, with some possessing flame retardant (UL94 V-0) characteristics.
Typical application scenarios
Automotive/Mechanical: Engine cylinder block, exhaust system, turbocharger seals, replacing traditional gaskets;
Industrial furnaces/HVAC: Sealing of flanges and observation windows for ovens, boilers, and hot air ducts;
Electronic and electrical: Sealing and sealing of heating equipment, photovoltaic junction boxes, sensors, and power modules;
Building fire prevention: Fire sealing of firewalls and cable penetrations.
Famous models and brands
DOWSIL 736, 732;
Henkel LOCTITE High Temperature Series;
3M 2000+flame retardant and high-temperature resistant silicone sealant.
Key points of construction and selection
The surface of the substrate must be clean, dry, and free of oil stains. If necessary, a primer should be used to enhance the adhesion;
Neutral curing type is more suitable for sensitive metals, coated glass, and electronic components;
Distinguish between long-term temperature resistance and instantaneous temperature resistance to avoid misuse leading to failure;
The construction environment needs to be ventilated, and the curing process should avoid contact with accumulated water.
