Flexible Silicone Sealing Adhesive For Electronics Applications

Semicosil 811 is processed together with a catalyst as a two-component silicone rubber and hardens through an addition reaction to form a soft elastomer that offers little resistance to deformation. The vulcanizate thus compensates for thermomechanical stresses in the adhesive bond. For processing, Semicosil 811 is mixed in a 10: 1 ratio with the catalyst component. By choosing the catalyst, the processor can decide whether the crosslinking should be activated thermally or by UV light.

For common dispensing procedures

The new sealing adhesive can be easily conveyed in common dispensing processes. It contains a UV fluorescent marker, which enables automated optical quality control of the adhesive application. Without the need for a primer, the new sealing adhesive adheres to polybutylene terephthalate, polyamide, aluminum, coated display glass and a number of other substrates commonly used in electronics.

Fast processing

Semicosil 811 can be processed much faster than conventional addition-crosslinking silicone sealing adhesives, according to the manufacturer. After the two components have been mixed and - in the case of the UV-activatable catalyst - irradiated with UV light, the adhesive strength builds up within one hour at room temperature so that the bond can be checked for leaks.

Oven-free curing

The sealing adhesive enables oven-free curing. The processor can thus avoid investing in expensive furnace systems, which significantly simplifies the production process. Because there is no heat load, Semicosil 811 is also suitable for use on thermally sensitive substrates. A small amount of energy after joining - for example by briefly storing the composite at a higher temperature or irradiating it with infrared light - accelerates curing and build-up of adhesion considerably.

High adhesive strength

With many substrates, an adhesive strength of over one Newton per square millimeter is achieved after less than ten minutes if the composite has only been exposed to a temperature of 80 ° C for two minutes. If a high-temperature test step is provided in the process, the manufacturer can also use this process to accelerate curing and build up liability. Such a test is intended for many electronic devices and is therefore often present in the overall process.

Large series production possible

With Semicosil 811, the electronics manufacturer has many ways of integrating sealing adhesive and leak testing into its overall process in such a way that cost-effective large-scale production with short cycle times is possible. As a silicone elastomer, the vulcanizate of the new sealing adhesive is characterized by high aging and temperature resistance and remains flexible even at low temperatures down to –40 degrees Celsius. This makes Semicosil 811 particularly suitable for use in automotive electronics. (mz)