Thermal conductive mud and its application in electronic products

1、 What is thermal conductive mud?

In the design and production of electronic products, interface thermal conductive materials are usually used between the heat sink and the heating device to dissipate the heat emitted by the chip. Common interface thermal conductive materials can be classified into liquid uncured, cured products, or pre formed products based on their morphology. Among them, liquid or paste products have the best thermal conductivity, such as thermal grease (thermal paste), which is used to fill the small gaps between interfaces to achieve the best thermal conductivity. The solidified thermal conductive material is used in a liquid state and solidifies into an elastic thermal conductive material after a period of time, such as single component thermal conductive adhesive, two-component thermal conductive silicone, and two-component thermal conductive potting adhesive. The pre formed materials include thermal conductive silicone gaskets with thermal conductivity ranging from 1.0W/m * K to 17.0W/m * K, which are particularly suitable for use in network processing equipment and various high-speed processors.

Thermal conductive putty, also known as thermal conductive putty, feels like a rubber putty for children to play with. It is made by adding thermal conductive fillers and polymer silicone oil to organic silicon materials, and then using advanced mixing technology. During the production process, the large molecular structure inside the thermal conductive paste is connected into a network, effectively preventing the leakage of high molecular weight silicone oil. Therefore, the volatile matter and oil leakage rate of the thermal conductive paste are very low. Moreover, silicon material is the most stable material in nature, and the use temperature of thermal conductive paste ranges from -60 ℃ to 200 ℃, and it will never dry out and fail. The thermal conductivity of thermal conductive mud ranges from 0.6W/m * K to 8.0W/m * K, and it can be used in electronic devices with excellent thermal conductivity. Compared with thermal grease, thermal mud has a higher viscosity and is harder than silicone grease. Users can shape it according to their needs and fill it between the electronic components that need to be cooled and the heat sink/housing, making it in close contact, reducing thermal resistance, quickly and effectively reducing the temperature of electronic components, thereby extending the service life of electronic components and improving their reliability. Thermal conductive paste does not crosslink (solidify), so when it is necessary to modify or replace the heat sink during electronic assembly, using thermal conductive paste is easy to operate.

2、 Application of Thermal Conductive Mud (Thermal Conductive Putty)

Thermal conductive mud has a certain degree of adhesion and will not dry out. It can adhere to high-temperature components in power sources or equipment to transfer heat. One typical application is in the driving power supply of LED bulb lights. In order to obtain UL certification for exported LED lights, manufacturers often use two-component potting adhesive for potting. Lights exported to the United States require a 50000 hour warranty, and currently the quality of LED chips is not a problem. The main fault is the power supply, which cannot be disassembled after being sealed with sealant and can only be scrapped and replaced as a whole. If thermal conductive mud is used to locally fill the power supply, it can effectively dissipate heat, and if there are problems with the power supply, it can be easily replaced to save costs for the enterprise. Of course, for lamp rows that require waterproof filling, it is not possible to achieve waterproofing and moisture resistance, and it is still necessary to use sealant.

Another typical application is the design of placing the power supply at both ends in LED fluorescent tubes. In order to minimize the size of the tube, the space for the two power supplies is relatively small. However, the power of a 1.2-meter LED fluorescent tube is usually designed to be 18W to 20W. In this way, the heat generation of the driving power supply becomes relatively large. Thermal conductive mud can be filled into the gaps of the power supply, especially attached to power devices, to help dissipate heat and extend the life of the lamp tube.

For some sealed module power supplies, thermal conductive mud can be used for local filling to achieve thermal conductivity.

3、 Instructions for using thermal conductive mud

Thermal conductive clay is like rubber clay, which can be molded into any shape by hand and has a certain degree of adhesion to adhere to the surface of the device. However, because thermal conductive clay does not have adhesive properties, it still needs to be matched with fasteners. When producing in large quantities, an appropriate amount of thermal conductive mud can be taken out of the packaging bucket, rubbed into a strip by hand, or pressed into a strip by a mold, and then cut into small pieces to ensure the quality of each part. It can be molded into the desired shape by hand, filled or attached to the corresponding area.

Another method is to make a mold in advance, take out an appropriate amount of thermal conductive mud from the packaging bucket, compact it in the mold, and use a scraper to scrape off the excess thermal conductive mud above. After opening the mold, small pieces of thermal conductive mud will be formed one by one, and then each piece will be filled to the desired place.

Because the hardness and viscosity requirements for thermal conductive paste may vary in different applications, a very special way of use is to use an air moving glue gun to extrude it outward. And this requires the thermal conductive mud to be packaged in the EFD dispensing syringe. This is much more convenient for users of thermal conductive mud, and manufacturers of thermal conductive mud not only require the ability to produce thermal conductive mud according to the formula, but also need to control the hardness and viscosity of the thermal conductive mud in the process to make it suitable for packaging in EFD syringes.