Bergquist’s latest edition to the gap filler family is the 3500S35, a thermally conductive, electrically isolating, liquid gap filling material that combines both an conductivity of 3.6W/m-K and exceptional softness. A key feature of is its ability to ‘wet-out’ the interface surface. This reduces air gaps, which increases surface area contact and so increases thermal conductivity at the interface. Prior to curing, Gap Filler 3500S35 maintains excellent thixotropic characteristics which makes it easy to dispense. The result is a gel-like material that fills air gaps and voids yet flows readily when required in the dispensing and assembly process.

The material is an solution for interfacing fragile components of various heights and stack-up tolerances to one heatsink or casing. Typical applications include automotive electronics, computers and peripherals, telecommunications and any other assembly where multi-height heat generating components must be efficiently thermally bonded to a heatsink. A two part material, Gap Filler 3500S35 also provides a more flexible cure schedule. Requiring no refrigeration during storage it can be used immediately and will cure in 15 hours at room temperature, or 25 minutes at 100°C. Once cured it remains a low modulus elastomer designed to assist in relieving thermal expansion stresses during thermal cycling yet maintain enough elastic modulus to prevent pump-out from the interface.