Sealant is designed for automotive control units

Connectors can be sealed using the Dualbond GE4918 light- and humidity-curing sealant from Delo.

The sealant (illustrated in pink) seals connectors with passivated silver pins, which are used in vehicle control units or sensors. It has good pin sealing properties, increases connector life and allows efficient production, says the company.

It is necessary that these connectors are reliably sealed, to protect electronics from humidity and corrosion. Automotive suppliers generally use silver coated connector pins because 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, however, which is considered difficult to bond.

The Dualbond GE4918 sealant has been optimised for these types of pins. It adheres well to the mercaptan coating and also to the typical connector housing materials PA and PBT, even under the stringent conditions of the automotive sector, reports Delo. The sealant is flexible in the cured state, which allows it to compensate for the different thermal expansions of metal pins and plastic housings. It offers temperature resistance up to +150 degrees C, and is able to keep the connectors tight after thermal shock tests at temperatures ranging from -40 to +150 degrees C.

The sealant also enables fast and simple production processes with a high level of safety, says Delo. 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 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.

The sealant means automotive suppliers can benefit from its silicone-like properties without having to take special precautions at the production stage, as is the case with silicones. The outgassing of silicone often leads to contamination of other processes, which impacts painting or coating processes.

The Dualbond GE4918 sealant is now available for sampling.

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