New polyurethane encapsulant from Multicore

Citation

(1999), "New polyurethane encapsulant from Multicore", Soldering & Surface Mount Technology, Vol. 11 No. 3. https://doi.org/10.1108/ssmt.1999.21911cad.017

New polyurethane encapsulant from Multicore

New polyurethane encapsulant from Multicore

Keywords Multicore, Encapsulants

E/U/1444 polyurethane glob-top encapsulant from Multicore Solders Inc. has exceeded the most severe relevant IEC standard by a factor of three, by passing 1,500 hours HAST testing with no failures. E/U/1444 is a two-part polyurethane material, developed by Multicore Solders Advanced Products Division to achieve environmental protection of components. As a low stress, protective encapsulant, it is suitable for applications including COB assemblies, large area multiunit substrates and components such as BGA devices. It is also hydrophobic and thus able to meet the demanding JEDEC A112 level 1 specification, relating to the effects of absorbed moisture within the encapsulant (known as "popcorning").

E/U/1444 has low viscosity at ambient temperature, and eliminates the requirement for substrate heating. Stress, leading to warpage of components and assemblies during manufacture, is minimised, and its low dielectric constant makes E/U/1444 suitable for high-frequency, high-speed applications.

The two-part E/U/1444 system displays good dispensing characteristics and is mixed automatically at the point of use by a dual cartridge fitted with a spiral mixer. The dispensed material gels after a few minutes at room temperature. Flow is self limiting, enabling the perimeter of the encapsulant to be defined without the use of dams.

The crown height can also be determined by the dispense pattern and low, flat-topped profiles are made possible on large-area components. Full curing is triggered at relatively low temperature, by heating to 80-100°C for 30 minutes.

E/U/1444 is available in dual cartridges for hand dispensing, and in bulk containers for use with twin reservoir mix/dispense machines. Evaluation kits are also available, and applications advice and technical support can be found by contacting Multicore Solders Advanced Products Division.

The E/U/1398 series offers the combined benefits of simplified deposition, void-free gap filling and perfect soldering action in one material.