With the rapid development of industries such as new energy vehicles, 5G, big data, autonomous driving, the Internet of Things, and industrial intelligence, the demand for thermally conductive materials has also risen sharply.
How many types of silicone thermal conductive materials are there?
1. Thermally conductive silicone sheet
2. Thermally conductive silicone grease
3. Thermal conductive silicone tape
4. Thermally conductive silicone tape
5. Thermally Conductive Phase Change Materials
6. Thermally conductive gap filler
7. High thermal conductivity potting compound
8. Thermally conductive adhesive
Different materials categories of silicone thermal conductive
1. Thermally conductive silicone sheet
(Also called thermally conductive silicone pad, thermally conductive silicone sheet)
It has good thermal conductivity and high-grade pressure resistance, which meets the current demand for thermally conductive materials in the electronics industry, and is a binary alternative to silicone grease thermal paste and mica sheets. The best product for the cooling system. This type of product is easy to install, conducive to automated production and product maintenance, and is a new material with great craftsmanship and practicability.
The thickness and hardness of the thermally conductive silicone sheet can be adjusted according to different designs, so the heat dissipation structure and the chip size tolerance can be bridged in the thermal conduction channel, reducing the tolerance requirements for the contact surface of the heat sink in the structural design, especially for The difference in flatness and roughness will greatly increase the cost of the product if the machining accuracy is improved. Therefore, the thermally conductive silicone sheet can fully increase the contact area between the heat-generating components and the radiator, transfer heat flow, reducing the production cost of the radiator.
2. Thermally conductive silicone grease
Thermally conductive silicone grease is a white or grey viscous object with a certain viscosity, no obvious granularity, non-toxic, tasteless, non-corrosive, stable chemical and physical properties and excellent thermal conductivity, electrical insulation, high-temperature resistance, aging resistance and water resistance.
It has low oil separation (tends to zero) and very good weather resistance (including high and low-temperature resistance, water resistance, ozone resistance, weathering resistance, etc.), and can be used for a long time at a temperature range from -30°C to 150°C, even at temperatures above +200°C. It can still maintain the wetting of the contact surface.
3. Thermal conductive silicone tape
It is widely used in the bonding between power devices and heat sinks drawing heat, which can achieve the functions of thermal conductivity, insulation and fixing at the same time.
4. Thermally conductive silicone tape
Silicone polymer elastomer with glass fiber as the base polymer material for reinforcement, also known as thermally conductive silicone cloth, tear-resistant silicone cloth, this silicone cloth can effectively reduce the thermal resistance between electronic components and heat sinks, and electrical insulation, with high dielectric strength, good thermal conductivity, high chemical resistance, can withstand high voltage and metal parts of the puncture caused by the circuit short circuit.
The thermally conductive phase change material uses the properties of the substrate to undergo a phase change in the working temperature, thus allowing the material to fit more closely to the contact surface and also to obtain an ultra-low thermal resistance for a more thorough heat transfer.
5. Thermally Conductive Phase Change Materials
It utilizes the characteristics of the base material to undergo a phase change at the working temperature, so that the material can better fit the contact surface. At the same time, ultra-low thermal resistance is also obtained, and heat transfer is carried out more thoroughly.
6. Thermally conductive gap filler
(Thermally conductive gel, thermally conductive filler)
Thermally conductive gap fillers are designed to optimize dispensing control, achieve superior thermal and mechanical properties, and offer highly engineered benefits. Because it is dispensed in a liquid state to fill gaps, the material exerts little stress on the part during assembly. Thermally conductive gap fillers can be used to join and coat the most complex topography and multi-layer surfaces, providing unlimited thickness coverage for uneven circuit board topography.
Thermally conductive filler
7. High thermal conductivity potting compound
It is a two-component addition type silicone rubber, which is composed of two parts of AB liquid. After mixing according to the proportion, it will react and cure into a high-performance elastomer. Provide excellent heat dissipation and moisture-proof potting protection for circuit board components.
Thermally conductive potting silicone
8. Thermally conductive adhesive
One-component room temperature curing silicone rubber has excellent adhesion to metal, plastic and ceramic surfaces after curing. It is widely used in filling and fixing electronic components and radiators to improve thermal conductivity and improve the stability of components. In particular, mechanically fixed structures cannot be realized.
Common Problems
Q1: Is the thermally conductive silicone gasket sticky?
A1: Thermal conductive silicone gaskets are available with or without adhesive.
Q2: How to understand "self-adhesion"?
A2: The rubber component contains adhesive, so the product itself has self-adhesive. For adhesive-backed products, the stickiness of the product surface will facilitate the assembly of the product. However, the thermal resistance of the adhesive backing will affect the thermal conductivity of the product. And the self-adhesive product will not have the problem of increasing the thermal resistance due to the adhesive backing. In terms of adhesive strength, the adhesive strength of the back adhesive is higher than that of self-adhesive products.
Q3: Can adhesive products be bonded repeatedly?
A3: It is necessary to judge whether it can be reworked according to specific conditions. If carefully constructed, generally sticky products can be reused. However, when encountering an aluminum surface or an electroplating surface, special care shall be taken to avoid tearing or delamination.
Q4: If the heat conductive gasket is self-adhesive, will it be convenient for reuse?
A4: It is necessary to determine whether the self-adhesive heat conductive pad treatment can be repeatedly bonded according to the specific bonding surface. In most cases, it can be reused, but when encountering an aluminum surface or electroplating surface, special care should be taken to avoid tearing or delamination. Heat conductive gasket with self-adhesive will be more easily reused than adhesive-backed products.
Q5: What is the production process of a heat conductive silicone gasket?
A5: Add heat conductive powder, flame retardant and curing agent to the organic silicone oil, mix and color match by stirring, then vacuum to reduce the bubbles in the silicone, then vulcanize at high temperature, cool down and then conduct rubber coating cutting and molding processing; Finished product testing items include thermal conductivity, temperature resistance range, volume resistivity, voltage resistance, flame retardancy, tensile strength, hardness, thickness and other parameters.
Q6: What is the upper limit of the normal working temperature of the thermally conductive silicone gasket? At the maximum temperature, how long can it be exposed to maintain normal?
A6: According to thermal conductivity measurements, the temperature limit for normal operation is 250 degrees for 5 minutes and 300 degrees for 1 minute.
Q7: Will the thermally conductive silicone gasket become soft when heated?
A7: Generally, in an environment of minus 60 degrees to 200 degrees, there will be no significant difference in hardness.
Q8: Is the thermally conductive silicone gasket insulating?
A8: It is insulating, but thermally conductive silicone gaskets are only thermally conductive gap-filling products after all, and are not recommended for high-voltage environments.
Q9: Is the thermally conductive silicones gasket leaking electricity?
A9: The silicone oil of the silicone sheet itself is insulating, and the thermal conductive powder and auxiliary materials added to it also have insulating properties, so there will be no electrical leakage.
Q10: How to use a thermal conductive silicone gasket?
A10: Keep the contact surface between the heat dissipation surface and the heat source clean, tear off the release film covering the thermal conductive silicone gasket, put it on the heat dissipation source, press the heat dissipation device and fix it.
Q11: Can thermal silica pads be used for notebook CPUs?
A11: The thermal conductive silicone gasket can be used as the thermally conductive medium to replace the thermally conductive silicone grease on the CPU. However, considering the space structure and heat dissipation scheme in the notebook, most of the notebooks on the market still use traditional silicone grease as the thermal conductive medium.
Q12: What is the price of thermally conductive silicone gasket?
A12: The price of the silica gel sheet increases with the increase of thermal conductivity and thickness. It is recommended to use the silica gel sheet as much as possible to meet the thermal conductivity of electronic products. The thickness is controlled at 1.1 times the distance between the heat source and the radiator.
Q13: What is the shelf life of thermally conductive silicone gaskets?
A13: Most thermally conductive silicone gaskets have a shelf life of 1 year after production, which is based on the fact that they can be removed from the packaging. It is recommended to use the gaskets within 6 months of production as the adhesive backing will affect the shelf life of the gaskets; in addition, the stability of the gaskets is not limited to the shelf life, as they have excellent thermal stability and weather resistance.
Q14: What is the lifetime of a thermally conductive silicone gasket?
A14: The life span of thermally conductive silicone gaskets is generally more than ten years. The silicone film is volatile, anti-aging, high and low temperature resistant, and has shock absorption and insulation effects, which can fully meet the life span of electronic products.
Through the above frequently asked questions, related to everyone for the thermal conductive silicone film has a certain understanding, I remind you of the attention is: the correct choice of the thermal gasket is to ensure that the key to equipment is leak-free. There are several types of gaskets available for the same working condition. The gaskets must be selected reasonably according to the physical properties of the medium, pressure, temperature and size of the equipment, operating conditions, length of the continuous operation cycle, etc., so as to avoid shortcomings and give full play to the characteristics of various gaskets.
