Silicone adhesive features high thermal conductivity and electrical insulation

19-04-2021 | Masterbond | Subs & Systems

Master Bond MasterSil 153AO is an addition-cured two-part silicone with a self-priming property. It provides a high tensile lap shear strength, especially for a silicone. The system is thermally conductive and electrically insulating.

“The key feature of MasterSil 153AO is that it provides the ability to minimise stress, with no compromise on strength. Although it is not considered a structural adhesive, it provides a truly remarkable combination of flexibility and strength that other silicones do not provide,” says Rohit Ramnath, senior product engineer.

This silicone product has an elongation between 100-120% and a tensile lap shear strength of 700-800psi. It gives a thermal conductivity of 0.93-1.08W/(m•K), a volume resistivity of more than 1014Ohm-cm, a coefficient of thermal expansion of 150-180 x 10-6in/in/C, and hardness of 65-75 Shore A. It is serviceable over the temperature range of -65F to +400F.

With a simple to use mix ratio of one to one by weight, the adhesive cures with the addition of moderate amounts of heat. The optimal cure schedule is overnight at room temperature followed by 2-4 hours at 135F-185F. Upon mixing, it maintains its smooth paste consistency and minimal flow. It has a long working life of four to six hours for a 100g mass at 75F.

This compound bonds well to multiple substrates, including metals, ceramics, glass, many plastics and silicone rubbers. It is provided for use in kits, with sizes ranging from half-pint, pint, quart to gallons. It is white in colour. It is generically low outgassing, contains no solvents, has low linear shrinkage upon curing and is RoHS compliant.

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