As requirements for electronic products such as mobile phones to be lighter, more miniaturized, and more integrated continue to rise, the gaps between their components and the pin feet have become increasingly smaller. However, these devices sometimes need to be exposed to relatively harsh application environments—for example, many people take their mobile phones into humid bathrooms while showering, or wear TWS earphones while swimming. Such demands mean that the entire circuit board or most components must be protected to prevent them from failing due to external short circuits, corrosion, or extrusion in harsh environments. In this kind of protection, adhesives play an irreplaceable role.