Mechanical properties of silicone thermal pad

The silicone thermal pad is generally installed between the frames of the heat dissipation device and mainly plays the role of heat conduction, buffering and shock absorption. In practical applications, in order to ensure that the thermal conductive gasket can be intact during assembly, can fill the gap correctly, and ensure that the gasket is not damaged and fallen off during use, it is generally necessary to evaluate the mechanical properties of the thermal conductive gasket.

The mechanical performance indicators of silicone thermal pad mainly include tensile strength, tear strength, compression rate and rebound rate, etc. Let us give a brief introduction below.

The tensile strength of the thermally conductive gasket refers to the tensile stress applied to the sample to make it rupture, and the tear strength refers to the tensile strength of the elongated film sample with cracks by the tensile testing machine, so as to measure the complete tear. The maximum force required by the specimen. Therefore, in addition to the thickness of the sample, it can generally be expressed in units of kN/m.

These two properties of thermal pads and the elongation at break obtained in the test at the same time, this will reflect the product's ability to deform under force The ratio of the compressed amount of the silicone thermal pad to the actual thickness of the free state after installation is called the compression ratio. The compression ratio of the gasket is generally a mechanical performance index to evaluate the compression performance of the gasket. The deformation characteristics of the gasket during the loading process are An important condition for forming the initial sealing ability, which has a great relationship with the compression rate and the rebound rate.

⒈ Generally speaking, the harder the gasket, the smaller the compression rate will be under the same pressure. Therefore, under the normal installation preload, it is easy to cause the structural damage of the gasket; the softer the gasket, the greater the compression rate of the gasket under the same pressure. The initial installation preload required during use will be greater, so that it is difficult to achieve the sealing effect.

⒉ The resilience and resilience rate of the gasket, the resilience rate of the gasket is the ability of the gasket to restore elasticity after the gasket is unloaded, and the ratio of the thickness of the gasket after removing the pressure for a period of time and the initial thickness. If the rebound rate of the gasket is large, it means that the gasket has strong compensation ability and good sealing effect; under the premise of meeting the requirements of the compression rate, the higher the rebound rate, the better. On the premise of meeting the requirements of the rebound rate standard, the larger the test value of the compression rate, the better. Therefore, in practical applications, gaskets with good sealing performance, moderate compression rate and as large a rebound rate as possible should be selected.