Tek Tip – Properties of Thermally Conductive Adhesives

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  • When the heat is on, 3M™ Thermally Conductive Adhesive Transfer Tapes can help control it.

    As today’s electronics continue to get smaller and their circuit density increases, the amount of heat they generate has substantially increased. If this heat isn’t removed, the operational lifetime and reliability of the products will be reduced. Thermally conductive adhesives are essentially adhesives mixed with conductive fillers such as ceramic, aluminum silicate or metal. The main role of the adhesive is to form a bond at interconnections. The filler in the adhesives is what helps transport heat away from otherwise hot surfaces and dissipates it to other, non-critical areas of the assembly, usually with use of a heat sink. The tapes are used often in electronic assemblies such as high-density circuitry or heat sinks. As with other adhesive solutions, 3M™ Thermally Conductive Adhesives Transfer Tapes provide an alternative to other forms of assembly attachment such as screws or rivets.

    Some things to consider when choosing a thermally conductive adhesive include:

    Thermal Properties - Thermal conductivity is the measure of a material’s ability to transfer heat and is measured by W/m-K. This measurement is the heat energy transferred per unit of time and per unit surface area divided by the temperature difference. Thermal impedance, measured in °C cm²/W, is the measure of how a material of a specific thickness resists the flow of heat. Finally, operating temperature range also plays an important role in a product’s ultimate selection

    Mechanical Factors Understanding where and how and where a product is being used and how thick the substrates are that will ultimately be bonded.   

    Dielectric Properties Dielectric strength measures the maximum electric field a material can withstand without breaking down and is typically measured in KV/mm. Volume resistivity, measured in ohm/cm, quantifies how strongly the material conducts an electric current. For instance, low resistivity indicates that a material easily allows the flow of an electric current.   

    Which Product is Right for My Application?

    3M has several “go to” thermally conductive adhesive transfer tape options to consider when you’re looking to beat the heat. These tapes are designed to conduct heat between heat-generating components and heat sinks or other cooling devices such as fans, heat spreaders or heat pipes. The products are also designed to operate short term at 125°C- 150°C and long term at 90°C-100°C.  

    3M™ Thermally Conductive Adhesive Transfer Tape 8805 is a 5 mil, ceramic filled tape with high mechanical strength and good “wet-out” properties making it ideal for rough surfaces and LSE (low surface energy) substrates.  

    3M™ Thermally Conductive Adhesive Transfer Tape 8810 is a 10 mil, ceramic filled tape with both higher thermal impedance and higher peel strength than 3M™ Thermally Conductive Tape 8805.  

    3M™ Thermally Conductive Adhesive Transfer Tape 8815 is a 15 mil, ceramic filled tape with even higher thermal impedance and higher peel strength.   

    Need additional help? Call Tekra today at 1-800-448-3572 for expert assistance or request a quote for 3M products designed for thermal management applications.     

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