Henkel’s Technomelt in a mould of its own

Technomelt encapsulates electronics at low pressure. After moulding, parts get tested and moved to final assembly. (Photo: Henkel)

Henkel’s low-pressure moulding technology for encapsulating electrical and electronic components in its Technomelt polyamide adhesive moulding compounds is increasingly being adopted for medical, electronic components, power and industrial automation, HVAC and lighting applications, states the company.

The technology offers numerous economic, process control, design and environmental advantages over alternative systems such as potting with reactive resin systems and high-pressure injection moulding.

Technomelt low-pressure moulding (LPM) technology was invented some 30 years ago by Henkel (formerly called Macromelt Moulding). The technology enables the quick encapsulation of delicate components by using specialised polyamides, in combination with standard processing equipment and low-cost moulds. “Because the material is injected at a lower pressure, compared to conventional injection moulding processes, and non-abrasive materials are used, risk of damage to the electronics during the encapsulation process is far lower,” comments Henkel.

Resistant to high stresses and very flexible

The technology is particularly adept at encapsulating discrete areas in complicated assembly where wiring is attached to a printed circuit board (PCB), PCBAs and other rigid component. One reason for this is that Technomelt resins, which are all unfilled, are resistant to high stresses and at the same time very flexible.

“I see Technomelt as an exciting part of our Circuit-Board Protection portfolio,” says Matthew Hayward, global key account for Power & Industrial Automation at Henkel. “It offers many unique advantages that traditional potting or conformal coating is not able to provide. It is particularly well suited to high-mix low-volume applications where throughput is key. The ability to apply this material only where is needed is a huge benefit. This enables one to ‘skyline’ an application [encapsulating only the components that require protection] or to significantly reduce the weight, due to substantially less material usage.”

Exceptional electrical insulation

The encapsulating material is said to provide exceptional electrical insulation, as well as resistance to a broad range of chemicals, extreme thermal cycling across high and low temperatures, and vibrations. The internal electronics are fully protected against outside elements, including ingress of water and dust, and long-term UV exposure.

Michael Otto, key account manager Engineering Adhesives for Low Pressure Moulding at Henkel, explains: “Unlike traditional two-component reactive potting compounds, the polyamides used in the Technomelt Low Pressure Moulding process are single-component thermoplastics, moulding cycle times are shorter and there are no emissions of volatiles. Whereas conventional potting can take as long as 24 hours to complete, the Technomelt Low Pressure Moulding process has a cycle time that can be as short as 30 seconds.”

High sustainability

Henkel Technomelt polyamide resins are compliant with the European RoHS (Restriction of Hazardous Substances) Directive and REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) regulations. “An additional important environmental feature of these polyamides, and one that is increasingly appreciated, is that they are largely bio-based, with up to around 80% of their content coming from renewable vegetable sources,” adds Otto.

Henkel offers a range of Technomelt Low Pressure Moulding resins that have been formulated for specific applications. Some, for example, have extra thermal resistance, others have improved toughness, or especially good adhesion to particular substrates.