What is the difference between epoxy resin and black vinyl as capacitor dielectric fillers?

Epoxy resin：

• A kind of high-molecular polymer, which forms thermosetting materials through the reaction of epoxy groups with curing agents. It features high insulation, strong mechanical properties and excellent sealing performance, and is widely used in the packaging and insulation of electronic components. After curing, it can form a rigid structure, but it has relatively high brittleness and weak impact resistance.
• When the capacitor is filled with epoxy resin, it is flame-retardant, explosion-proof and leak-proof, and with excellent insulation performance, high thermal stability, strong reliability, and high compressive strength. It can be used in outdoors and can be mounted upside-down.
• The cost is relatively high and the filling process is relatively complex, requiring precise proportioning when mixing the A&B materials.
• Industrial-grade capacitors tend to fill with epoxy resin.

Black Vinyl：

• It is a highly purified substance of asphalt, featuring high flame retardancy and low acid value.
• When capacitor adopts the vinyl mixture as filler, semi-dry type has the characteristics of fluidity, relatively good heat dissipation and low cost. The process is simple and does not require complex curing. It has a certain elasticity and can buffer stress, which can reducing the risk of the metallized film in the capacitor falling off due to deformation when is hit.
• However, it is prone to melting at high temperatures, has poor stability and can not be mounted upside-down.
• If only low cost is considered and the ambient temperature is not high, this is a good choice.