The new technology combines the process steps of dispensing and preactivation by light, which enables innovative approaches to product design (Figure: DELO).
With activation on the flow, DELO has developed an innovative process technology combining adhesive dispensing and preactivation in a single process step for the first time. This provides users with new options for designing their products and processes while reducing costs and CO2 emissions. The new technology is particularly suitable for bonding and encapsulating temperature-sensitive electronic components and offers an alternative to bonding processes previously used in industry.
What is new about the so-called activation on the flow is that the adhesive is already irradiated during the dispensing process, which starts the curing reaction even before the adhesive meets the component. After the combined process step, the components can be joined.
Another special feature of the technology is that the exposed adhesive areas can be additionally irradiated and fixed after joining. This provides immediate initial strength, preventing the adhesive from flowing out and the components from slipping, which allows them to be further processed right away. Whether with or without additional light fixation: the adhesive cures reliably to final strength without any additional process step, even in undercuts and shadowed areas.
The adhesives developed specifically for activation on the flow are one-component products based on epoxy resin. The patented DELO KATIOBOND FA adhesives contain two different initiators that react to different wavelengths and initiate curing. It is only thanks to this dual-initiator system that the optional light fixation step is possible. The adhesives are available with different mechanical properties and are highly resistant to media and temperature in the cured state.
In addition to process technology and adhesives, DELO has also developed the appropriate device: DELO-ACTIVIS 600 consists of two subunits, one for dispensing and one for irradiation. Dispensing is done on a volumetric basis, with flow rate and quantity being defined according to process requirements. As the one-component adhesive passes through the mixing tube, it is irradiated via integrated DELOLUX 503 curing lamps. The mixing coil ensures uniform activation of the entire adhesive volume. DELO-ACTIVIS 600 can be used as a stand-alone device or integrated into existing production systems.
“With activation on the flow, we have developed a complete system combining process technology, adhesive and device, which enables innovations on the customer side,” said Dr. Karl Bitzer, Head of Product Management at DELO. “The various customizable parameters open up completely new possibilities in terms of component design, efficient processes, and CO2 reduction.”
Activation on the flow is particularly suitable for bonding and encapsulating temperature-sensitive components. For example, sensors or connectors can be bonded in a “gentle” way and with low stress using dual-initiator adhesives. None of the components need to be transmissive to light, and the adhesive cures reliably even in complex geometries.
Activation on the flow can replace various bonding processes widely used in the industry. It is an efficient and environmentally friendly alternative for heat-curing, room-temperature-curing, or dual-curing processes, can overcome previous limitations, and creates room for innovation.