What Is Thermal Silicone Pad Made Of?

What Is Thermal Silicone Pad Made Of?

Thermal silicone pad is a thermally conductive medium material synthesized through a special process. In the industry, it is also known as thermally conductive silicone pad, thermally conductive silicone sheet, soft thermally conductive gasket, thermally conductive silicone gasket, etc. It can fill the gap, complete the heat transfer between the heating part and the heat dissipation part, and also play the role of insulation, shock absorption, sealing, etc. It can meet the design requirements of miniaturization and ultra-thinning of equipment, and it is very manufacturable. and practicality, and the thickness is suitable for a wide range.

Although Thermal silicone pads are widely used in the industry, for many people, the production process and production process of Thermal silicone pads have always been a mystery. The film production process and production process flow, and even unrelated personnel are not allowed to enter the production site to visit. Today, Nuofeng electronic Thermal silicone pads manufacturer will satisfy everyone’s curiosity, and share with you the production process of CoolThermo high Thermal silicone pads and the production process of Thermal silicone pads, so that all customers and friends who read this article can understand the thermal conductivity Have a comprehensive understanding of the production process and production process of silicone sheets.

At present, there are two main methods for the production process of silicone thermal pads: one is the silicone thermal pads that is made of mixed rubber solid (solid silicone) and pressed into a mold. The product material produced by this process is vulcanized with peroxide. It requires multi-layer production processes such as rubber mixing, opening refining, trimming, weighing, molding, tearing flash, and sulfur extension. The main features of this technology are that the quality of the finished product is better controlled, the quality stability is high, and the cost is low.

The other is a liquid silicone rubber injection molding product. This process is directly produced by a liquid silicone rubber injection molding machine. After the machine is installed, the entire material flow is carried out in a sealed state, without manual intervention and without production. Environmental impact, and the material is made of platinum as a vulcanizing agent, and the environmental protection performance is very good. This technology has high production efficiency, but it is difficult to grasp the pre-configuration of ingredients, and the product performance cannot be changed in the middle.

Now, CoolThermo will introduce to you the production process of thermal conductive silica gel pads prepared from solid silica gel. The production process and production process of high thermal conductivity silicone sheet mainly include five steps: raw material preparation → plasticizing, mixing → molding and vulcanization → trimming and cutting → finished product inspection.

Raw material preparation

Ordinary silicone has a low thermal conductivity and poor thermal conductivity, generally only about 0.2W/m.K. If the corresponding thermal conductive filler is added to the ordinary silica gel, the thermal conductivity of the silica gel can be greatly improved. The most commonly used thermally conductive fillers in the production process are as follows: metal oxides (such as Al2O3, MgO, BeO, etc.), metal nitrides (such as SiN, AlN, BN, etc.); the thermal conductivity of fillers is not only related to the material It is related to itself, and is closely related to the particle size distribution, morphology, interfacial contact, and intramolecular bonding degree of thermally conductive fillers.

In general, fibrous or foil-like thermally conductive fillers have better thermal conductivity. The price of thermally conductive fillers is also very different. The price of good thermally conductive fillers is more than ten times higher than that of inferior thermally conductive fillers. This is also the main reason for the large price difference of silicone thermal pads on the market.

When preparing raw materials, the ingredients must be accurately weighed according to the formula. In order to make the raw rubber and the compounding agent mix evenly with each other, some materials need to be processed. Re-cut and break the glue into small pieces; block compounding agents such as paraffin, stearic acid, rosin, etc. need to be crushed; liquid compounding agents (pine tar, coumarone) need to be heated, melted, evaporated water, and filtered of impurities; powder If the compounding agent contains mechanical impurities or coarse particles, it needs to be screened and removed.​​

Plasticizing, mixing

Plasticizing and kneading is a process in the processing of silica gel. The raw rubber itself is elastic, but it lacks the necessary plasticity during processing, so it is not convenient for subsequent processing and shaping. In order to improve the plasticity of raw rubber, it is necessary to masticate the raw rubber. Reduce the molecular weight and viscosity of the raw rubber to improve the plasticity of the raw rubber, and at the same time make the raw rubber produce proper fluidity to meet the needs of further processing in mixing and molding. The raw materials of thermally conductive silicone sheets are generally destroyed by mechanical high-speed stirring. After color matching and mixing, it changes from milky white silica gel to various colors.

Molding and vulcanization (molding method: calendering, scraping, plastic bonding)

The performance of the silicone thermal pads needs to meet the flexibility, elasticity and tear resistance at the same time, so it is necessary to perform a secondary vulcanization (curing) operation on the silicone thermal pads. After the liquid thermal conductive silicone is heated and formed in the early stage, its cross-linking density is not enough, and it needs to be further vulcanized to increase the tensile strength, resilience, hardness, swelling degree, density and thermal stability of the silicone thermal pads. Vulcanization is a great improvement over primary vulcanization. If the secondary vulcanization is not carried out, the performance of the silicone thermal pads produced may be affected to a certain extent, and a product with better performance cannot be obtained. The performance parameters of the silicone thermal pads after primary vulcanization are not exactly the same as those of secondary vulcanization, which are related to the actual operation process and steps.

Trimming and cutting (cutting method: slicing, die cutting)

The silicone thermal pads after high temperature treatment needs to be placed for a period of time, and other rapid cooling methods cannot be used quickly. Instead, it needs to be naturally cooled and then cut into different shapes and sizes according to the size provided by the customer, otherwise it will directly affect the thermal conductivity of the silicone thermal pads. Product performance.

Finished product inspection

After the silicone thermal pads is made into a finished product, some related items need to be tested, including: thermal conductivity, working temperature, breakdown voltage, volume resistivity, flame retardancy, tear strength, thickness, hardness, etc. As a well-known manufacturer of thermal silicone gaskets in the industry, all products of CoolThermo must meet the UL94-V0 level of flame retardancy, and comply with the EU ROHS directive and REACH certification requirements.

Through the detailed explanation of the production process and production process of the thermal silicone pads by CoolThermo above, I believe that everyone will have a more comprehensive understanding of the production process of the thermal silicone pads from raw materials to finished products. Only by having a clear understanding of the production process of the high thermal conductivity silicone sheet can we accurately judge the performance of the thermal silicone pads and provide more reference for selecting the appropriate thermal silicone pads.

As a benchmark enterprise in the thermal conductive silicone sheet industry, CoolThermo has passed the ISO9001 quality management system certification. Each silicone pads production process is operated in strict accordance with the requirements. The combustion level is required to reach the UL94-V0 level and comply with the EU ROHS directive. CoolThermo Thermal Conductive Silicone pads has a wide range of thickness options, the conventional thickness is from 0.15mm-15.0mm, and other thicker ones can also be customized. The thermal conductivity span is large, the thermal conductivity is complete from 1.0-10.0W/mK, and the sample test is free; there is enough stock, there is always a suitable one for you, welcome to visit the factory.

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