Many companies require that every material in their products be UL-approved.
What is usually meant by "UL-approved" is that the material must be flame retardant and thus meet the requirements of the standard UL 94, which is prepared by UL (Underwriter Laboratories) in the USA. Tribotec can currently offer three different circuit board varnishes that are approved according to UL94 V-0: the two moisture-curing varnishes ECC3010 and ECC3050S, as well as heat curing ECC4865.
The UL94 V-0 standard means that the material should go out within 10 seconds if you first set fire to it with a 1000 degree hot flame. This means that the material in practice does not burn at all. Read more about the test criteria in UL94 here.
The table below is from UL's website, file E135148.
Both ECC3010 and ECC3050S are very fast curing
The advantage of a moisture-curing varnish is the ease of use: spray or pour the varnish over the components, and let it stand. The varnish hardens with the help of the humidity of the air and does not need extra heat. A 100 micrometer (0.1 mm) coat of ECC3010 cures in just 10 minutes in normal humidity, and is dust-free after just 3 minutes. For the ECC3050S, the corresponding figures are 30 and 5 minutes respectively. If it is not fast enough, you can also heat to 60-70 degrees and get a thorough curing in 2 minutes. With such short curing times, you may not even need to consider UV-curing varnish.
ECC4865 does not harden until heated
In some situations, you want a long open time at room temperature, for example if you need dip coating and cover the entire circuit board. A moisture-curing varnish is difficult to dip varnish with: it wants to harden with moisture and if you have the varnish in a bucket where you dip, you immediately get a film of silicone rubber on the surface as soon as the varnish in the bucket comes into contact with air. Then it is better to use a thermosetting varnish: ECC4865. It needs to be heated to over 105 degrees, preferably 120, but then it hardens in just a few minutes. The majority of electronic components can handle this without any problems.
All circuit board varnishes from Tribotec are solvent-free
Despite the fact that our materials have a very low viscosity and a short curing time, they are completely solvent-free. The varnishes are developed in Japan by Momentive Performance Materials, formerly GE Toshiba Silicones. The varnishes also have a very faint smell and are not classified as thermosets according to The Swedish Work Environment Agency regulation AFS 2005:18, the so-called thermoset announcement. They are also free of tin compounds. Therefore, no special extraction or other adaptations of the production premises are needed.
