Author: Yu-Hsiang, Cheng
Along with the development of technology, the design of electronic products becomes smaller. It is more complicated if the necessary parts need to put into the small electronic product. In the past, UV adhesive was used for this application, but it cannot cure in the dark area due to the complex design of a mechanism that can affect the electronic parts. Therefore, the UV moisture dual curing adhesive which is one of the methods.
At the beginning of last year, Everwide has developed a low viscosity UV moisture dual cure conformal coating adhesive, which can be used for coating and soaking operations as a waterproof and dustproof protective adhesive for substrates. However, the viscosity is too low, it cannot use for the normal application of structural adhesive. Finally, Everwide successfully developed the FD series of UV moisture dual curing structural adhesive.
FD300-1 has a viscosity of 10,000 cps, and the thixotropic index is 1.7 (Figure 1). It is suitable for dispensing in the gap between two tiny parts to prevent the adhesive from soaking. Even though the part of the adhesive infiltrate, the moisture is used for curing to avoid the dispersion of other chemicals (Figure 2), which may damage other electronic components. FD003-1 has an excellent bonding strength after being irradiated with ultraviolet light, and the bonding strength can be even higher after a few days (Figure 3). In addition, it has fluorescent features and can also have the function of real-time inspection on the production line (Figure 4).
It is common to use a dual curing method for the shadow area. The UV light was usually fixed in the middle part, if the workpiece blocked the curing area, it might not be cured (Figure 5). This problem can be solved by using dual curing systems. Moreover, some of the colloids will penetrate into the concave area which the light cannot be irradiated. At this moment, the moisture can be used for curing to eliminate the pollution of uncured substances (Figure 6). Apart from the above application, as long as the mechanism's design requires rapid UV curing and has a shadow area, you can try to use UV moisture dual cure adhesive.
The application of UV moisture dual cure adhesive is not the same as UV curing adhesive because some of the workpieces cannot stand for high-temperature or cannot be used for alkaline substances. The above limitation can be carried out by using moisture. The adhesive can operate at low temperature, and it does not have many conditions on the bonding substrate. Everwide will gradually cooperate with the customers to customize the suitable adhesive. You are welcome to contact us.
