Thermally Conductive Epoxy Adhesives

Master Bond's thermally conductive adhesives offer superior heat dissipation for a wide range of electronic applications. Both one and two component systems are available for use. They include epoxies, silicones and other elastomeric products. Special formulations designed for unusual service conditions are also available.

Formulating Thermally Conductive Compounds

Thermal conductivity of a typical unfilled epoxy system has a very low value of 0.14 W/(m•K). This key property can be increased by adding metallic or ceramic fillers to the adhesive formulation. The type of filler, concentration of particles, their size and shape will determine the thermal conductivity of the product. They can be either electrically conductive or electrically insulative, as illustrated in the diagram below.

The chart below illustrates thermal conductivity values that can be achieved for select grades of systems with different fillers:

Key factors influencing heat dissipation effectiveness

Master Bond thermal interface materials (TIMs) are often applied between heat generating electronic components and cooling devices such as heat sinks. These systems are compounded to fill in thermally insulative air gaps, maximize heat transfer efficiency, improve device reliability and extend longevity. The following factors minimize the thermal resistance:

• High thermal conductivity
• Minimal bond line thickness
• Complete polymerization
• Elimination of voids

Thin Bonds Maximize Heat Transfer Properties

The lower the thermal resistance, the better the heat transfer. In this regard, Master Bond utilizes the principles based on the formula:

R=t/K

(where “R” is the thermal resistance; “t”, the thickness and “K” the thermal conductivity of the material). Master Bond epoxy thermal interface materials feature ultra thin bond lines to improve heat transfer characteristics. Thicknesses as small as 10-15 microns can be achievable using some compounds.

Common Applications Featuring Thermally Conductive Adhesives

Thermally conductive formulations are used for bonding, coating, potting and encapsulation applications in a wide variety of industries. Some specific applications include:

• Heat sink bonding
• Potting/encapsulating sensors
• BGA die heat spreader interface
• Chip scale packages
• Power semiconductors

Master Bond thermally conductive adhesives offer convenient room temperature or heat cure schedules in controlled production environments. Many systems withstand 1,000 hours at 85°C/85% RH. They can be serviceable in a wide range of temperatures from 4K to over 500°F. Specific systems are designed to offer superior dimensional stability, adhere well to substrates with dissimilar coefficients of thermal expansion and resist vibration, impact, shock. They can be dispensed manually or automatically. Select two component grades are available for use in premixed and frozen syringes.