Loctite TC 4

Loctite TC 4 is a high-performance, white silicone, grease specifically formulated for efficient heat transfer in high-temperature electronic applications. This non-curing thermal paste is designed to eliminate air gaps between heat-generating components and heat-dissipating structures, such as radiators or chassis. It provides a highly conductive thermal path while maintaining excellent electrical insulation, making it a reliable solution for mounting semiconductor devices, thermostats, and power resistors.

In its uncured state, TC 4 features a paste-like consistency with a density of 2.35 g/cm³. Unlike traditional adhesives, this material is designed to stay “wet”—it will not harden or dry out even after prolonged exposure to its maximum operating temperature of 200°C. It can be applied using syringes, automatic dispensing equipment, or a small, stiff brush. For best results, surfaces should be clean and free of debris; applying a thin film and squeezing out excess material when surfaces are mated helps to minimize thermal resistance.

Once applied, Loctite TC 4 achieves a thermal conductivity of 0.6 W/(m-K), effectively bridging the microscopic imperfections of metal surfaces. Its electrical properties are equally robust, featuring a high dielectric strength of 19.7 V/mm and a volume resistivity of 1×10¹³ Ω • cm preventing electrical leakage in high-voltage assemblies. The material remains physically stable over a broad temperature range of –40°C to +200°C. While slight filler separation may occur during long-term storage at elevated temperatures, the conductive fillers can be easily redispersed by hand or mechanical mixing to restore full performance.