Silicone rubber is a linear polymer material, the main chain is composed of silicon oxygen bond with strong bonding energy, with excellent light resistance, anti-aging properties, dielectric properties, corrosion resistance, mildew resistance and excellent chemical stability. Because of these comprehensive properties, silicone rubber is widely used in "thermal interface materials". However, the thermal conductivity of pure silicone rubber products is low, and its thermal conductivity is about 0.168W/(m·k), which is difficult to meet the needs of users when directly applied to "thermal interface materials". In order to improve its thermal conductivity and broaden its application scope in the field of electronics, the most commonly used method is to disperse the high thermal conductivity filler into the silicone rubber matrix to form sufficient heat conduction chain similar to the network structure, in order to improve the thermal conductivity of the silicone rubber based "thermal interface material". This issue of Baiyun Online, lead you to understand several commonly used silicone rubber based "thermal interface materials".

1. "Thermal interface material" based on alkyl silicone oil
The commonly used products of "thermal conductive interface materials" based on alkyl silicone oil are thermal conductive silicone grease or silicone paste, which takes dimethyl silicone oil, methyl phenyl silicone oil or methyl long chain alkyl silicone oil and other alkyl silicone oil as the base oil, and is prepared by mechanically mixing thermal conductive compounds or metal powder (such as alumina, zinc oxide, boron nitride, aluminum powder, copper powder or silver powder) as the thickening agent. This kind of product has good stereotyping at any time, no flow, high thermal conductivity, no solidification, no corrosion to the interface material and other characteristics, is widely used in electronic equipment, electrical equipment, communication equipment, power module and other fields, to solve the thermal conductivity and heat dissipation problem between electronic components and heat dissipation plate or heat dissipation plate. Its main product performance indicators are thermal conductivity, oil separation, cone penetration and so on.

2, with hydroxyl silicone oil as the matrix condensation type of "thermal interface material"
Hydroxy-silicone oil as the matrix condensation type of "thermal interface material" is usually α, ω-dihydroxy-dimethylsiloxane as the base polymer, mixed with high thermal conductivity filler under high temperature vacuum conditions to prepare the masterbatch, after completion, and crosslinking agents, catalysts and other characteristics of additives in the isolation of moisture in the high-speed dispersion mixer mixed evenly. The discharged products are usually packaged in sealed canisters or hoses, and the packaged products are divided into one component, two components, and even multiple components. When used, the extruded product is a paste, which is cured by crosslinking reaction in contact with water molecules and releases small molecules. Common condensation-type "thermal interface materials" have thermal flame retardant adhesive, thermal adhesive, thermal potting adhesive and other products, which are widely used in solar photovoltaic, automobiles, computers, mobile phones, new energy and other electronic and electrical fields to ensure the safe, stable and reliable operation of thermal electronic components during work. Its main product properties are conventional properties (such as surface dry, thin consistency, etc.), mechanical properties (such as tensile strength, elongation, etc.), electrical properties (such as volume resistivity, dielectric strength, etc.) and thermal conductivity.

3. "Thermal conductive interface material" with vinyl silicone oil as matrix
The "thermal conductive interface material" is composed of polyorganosiloxane containing vinyl as the base polymer, thermal conductive powder as the filling material, hydrogen-containing silicone oil as the crosslinking agent and other special components. The reaction principle is that under the catalysis of the eighth group transition metal compound (such as Pt, etc.), the polysiloxane is subjected to hydrosilylation reaction with multi-Si-H bond polysiloxane to form a new Si-C bond, so that the linear siloxane is formed into a network structure, and after the reaction is completed, the cross-linked elastomer is formed. In the reaction process, this kind of silicon rubber based "thermal interface material" has the characteristics of no by-products, small shrinkage rate, high conversion rate, easy to control the cross-linking rate, and no corrosion to the contact substrate. According to the packaging form of the product, there are two types of single component and two components, and the market is dominated by two components. Common products are silicone thermal potting adhesive, silicone gel and other products, mainly used in automobiles, consumer electronics, cable accessories and other electronic components and circuit board insulation potting, play a good sealing protection, cushioning, heat dissipation and other functions. Compared with the performance of the condensed "thermal interface material" product, the additive molding is generally different from the rubber type and the gel type, and the corresponding product control standards are inconsistent, and the process formulation, test performance, and control of test items are adjusted according to the actual use.