Dual-curing sealant for automotive electronics
23 July 2020
DELO has introduced a light- and humidity-curing sealant for connectors that are often found in vehicle control units or sensors.
DELO DUALBOND GE4918 offers very good pin sealing properties, increases connector life and allows efficient production.
It is necessary that connectors are reliably sealed to protect electronics from humidity, media, and corrosion.
Automotive suppliers generally use silver-coated connector pins since they are more cost-efficient than gold and more reliable than copper. The silver is given an additional passivation layer to protect it from tarnish and abrasion. This coating is usually based on mercaptan and has been considered difficult to bond – until now.
DELO DUALBOND GE4918 has been optimised for reliable sealing for these types of pins. It not only adheres very well to the mercaptan coating, but also adheres to the typical connector housing materials PA and PBT, even under the stringent conditions of the automotive sector.
Since this new sealant is flexible in the cured state, it also compensates for the different thermal expansions of metal pins and plastic housings.
It offers very good temperature resistance, up to +150 °C, and is able to keep the connectors tight after thermal shock tests ranging in temperature from -40 °C to +150 °C.
Suitable for mass production of connectors
DELO DUALBOND GE4918 enables fast and simple production processes with a high level of safety. The one-component product is easy to dispense, shows good flow properties, and can be fixed in 10 to 20 seconds with the help of high-intensity UV light.
In shadowed areas that cannot be reached by light, a second curing mechanism allows the adhesive to fully cure under the influence of air humidity. An in-line tightness test can be performed immediately after UV light fixation.
With this new sealant, automotive suppliers can benefit from its silicone-like properties without having to take special precautions in their production, as is the case with silicones. The outgassing of silicone often leads to contamination of other processes, which is particularly undesirable in painting or coating processes.
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