Loctite D 125 F 3

Loctite D 125 F 3 is a high-performance, one-component, epoxy adhesive engineered for ultra-high-speed dispensing in surface mount technology (SMT). Specifically formulated for use with high-speed pneumatic and positive displacement dispensers, this yellow paste is designed to secure chip capacitors, resistors, and other surface mount devices (SMDs) onto printed circuit boards before wave soldering. Its primary benefits include a low exotherm, minimal water absorption, and a “non-sag” profile that prevents the adhesive from slumping during the thermal transition into the cure cycle.

In its uncured state, the material features a plastic viscosity of 38,000 mPa·s and a high calculated yield of 260 N/m², which ensures excellent dot profile stability and prevents “stringing” during high-frequency needle dispensing. It is optimized for versatile processing, offering multiple heat-cure schedules such as 10 minutes at 120°C in a convection box oven or as little as 2.5 minutes at 120°C in an IR or convection conveyor oven. To maintain its chemical properties, the product should be stored between 0°C and 8°C and allowed to thaw for 8 to 12 hours to reach room temperature before use.

Once heat-cured, Loctite D 125 F 3 forms a robust mechanical bond with a tensile lap shear strength exceeding 1,160 psi (8 N/mm²). It exhibits a glass transition temperature of 72°C and a Shore D hardness of >80, providing the mechanical rigidity necessary to withstand the turbulence of a wave soldering bath. Electrically, it provides a volume resistivity of 1×10¹⁴ and successfully passes Bellcore electromigration testing, ensuring that the adhesive does not compromise the electrical performance or long-term reliability of high-density electronic assemblies.