Introduction to the function and use of thermal silica gel

Thermally conductive silica gel, also known as thermally conductive glue, thermally conductive silicone rubber, etc., is based on organic silica gel as the main body, adding fillers, thermally conductive materials and other polymer materials mixed with silica gel, with good thermal conductivity and electrical insulation properties.

Ordinary thermal conductive silica gel is added with aluminum oxide, etc., and high thermal conductive silica gel is added with thermal conductive materials such as boron nitride. Manufacturers of thermally conductive silicone adhesives or potting materials can generally produce different thermal conductivity, curing speed, viscosity, color, hardness, etc. according to their needs.

As a silicone rubber matrix with excellent insulation and shock absorption properties, its thermal conductivity is only about 0.2W/mK, but by adding high-performance thermal conductive fillers to the matrix, including metal fillers (such as Al, Cu, MgO, AIN) , BN) and non-metallic materials (such as SiC, graphite, conductive carbon black, etc.), its thermal conductivity can be improved several times or even dozens of times. The thermal conductivity of thermal silica material is ultimately determined by the silicone rubber matrix, filler performance, filler ratio, filler distribution, and processing technology.

Thermally conductive silica gel includes room temperature vulcanized and high-temperature vulcanized silica gel. This type of silica gel generally includes thermally conductive silicone adhesives, thermally conductive encapsulants, and thermally conductive gaskets that have been vulcanized into a certain shape.

Generally, the thermal conductivity of high-temperature vulcanized thermal silica is slightly inferior to that of room-temperature vulcanization. High-temperature vulcanized thermal silica is mainly used in the form of sheets as a gasket or heat sink; it is mainly used for elastic bonding in electronics, electrical appliances, and instrument industries. , Heat dissipation, insulation and sealing, etc., thermally conductive silica gel can provide the high flexibility and heat resistance required by the system, and can quickly transfer the heat of the system.

The thermal conductivity of different thermal silica gels varies greatly. The cost price difference is also great (but if insulation is not required, the production cost can be greatly reduced and a high thermal conductivity can be achieved).

Thermally conductive silica gel is a high-end thermally conductive compound. The non-conductive properties of the product can avoid risks such as short circuits; it has the effect of cooling and bonding electronic devices. It can be cured into a higher hardness elastomer in a short time. After curing, it is closely attached to the contact surface to reduce the thermal resistance, which is beneficial to the heat conduction between the heat source and the surrounding heat sink, main board, metal shell and outer shell. Thermally conductive silica gel has the advantages of high thermal conductivity, good insulation performance, and ease of use. It has good adhesion to metals including copper, aluminum, stainless steel and other metals. The curing form is dealcoholized and does not corrode metal and non-metal surfaces.

Thermally conductive silica gel can be widely applied to the contact surface between the heating element (power tube, thyristor, electric heating pile, etc.) and heat dissipation facilities (heat sink, heat sink, shell, etc.) in various electronic products and electrical equipment, It acts as a heat transfer medium and has the properties of moisture-proof, dust-proof, corrosion-proof and shock-proof. It is suitable for surface coating or integral potting of various microwave devices such as microwave communication, microwave transmission equipment, microwave special power supply, and stabilized power supply.

It is widely used to replace thermal grease and thermal pads as filling and bonding between CPU and radiator, thyristor intelligent control module and radiator, transistor and electric thermistor connection, high-power electrical module and radiator. After using this glue, the traditional connection method of using cards and screws can be removed, and the result is more reliable filling and heat dissipation, simpler process and more economical cost.

Such as: integrated circuits, microcomputer processors, memory modules, cache memories, sealed integrated chips, DC/AC converters, IGBTs and other power modules, semiconductors, relays, rectifiers, transformers, etc., which can be widely used in personal portable computers Package. Fixing of electronic and electrical components, flame-retardant, heat-conducting, insulating, shock-proof and moisture-proof sealing. Heat dissipation of high-power LED products. It is especially suitable for bonding and sealing with higher requirements for thermal conductivity.

The correct use of thermal silica gel

1. Clean the surface: clean up the surface of the sticky or coated object to remove rust, dust and oil.

2. Gluing: Unscrew the cap of the rubber tube, first pierce the seal with the tip of the cap, squeeze the glue onto the cleaned surface, make it evenly distributed, and close the adhesive surface to fix it.

3. Curing: Putting the painted parts in the air will cause the phenomenon of skinning slowly, and any operation should be completed before the surface skinning. The curing process is a curing process from the surface to the inside. Within 24 hours (room temperature and 55% relative humidity), the glue will be cured to a depth of 2 to 4 mm. If the position is deep, especially in the part that is not easily exposed to air, The time to fully cure will be extended, if the temperature is lower, the curing time will also be extended.

4. Do not move, use or pack the operated parts before they reach sufficient strength.

5. Storage: The unused glue should be tightened and sealed immediately.

Precautions

After the operation is completed, the unused glue should be tightened immediately and sealed and stored. When using it again, if there is a little skin on the seal, just remove it, and normal use will not be affected. During the storage of the glue, a small amount of solidification may also occur at the mouth of the tube. After it is removed, it can be used normally without affecting product performance.

This product will release a small amount of by-products during the curing process, which may cause slight irritation to the skin and eyes. It is recommended to use it in a well-ventilated place. If you accidentally touch the skin, wipe it clean, and then rinse with water; if you accidentally touch your eyes, rinse with water and go to the hospital for examination.

The above is an introduction to the definition, characteristics, functions and usage of thermal silica gel. Only with sufficient understanding of thermal silica gel can we more accurately select the thermal silica gel solution and achieve better performance in practical applications. Nowadays, there are many manufacturers of thermal conductive silica gel on the market, and they are widely used. They are mainly used in the optoelectronic industry, computer industry, network industry, home appliance industry, semiconductor lighting industry, etc.; currently 5G and new energy are a development trend, and thermal conductive silica gel is It can be seen that the development trend of thermally conductive silica gel is immeasurable, and the future is bright.