Our research revealed that all solid two component encapsulation compound (Polyurethane & Epoxy) partially lose their ability to prevent ion migration through the compound under strong electric field mainly due to the fact that these polymeric materials develop micropores due to ageing expansion and seasonal temperature cycling. Once the encapsulation compound loses its high resistance towards ion migration, the film with rough surface easily breath all available ions resulting in the fast deterioration of the capacitor element.

The quality issue due to surface roughness of the film remains passive and hidden inside the capacitor during the initial stages and will appear after 7 months or above making it difficult to ensure the consistency of the product performance. Hence the only solution to produce good quality MPP capacitor is to use MPP film with smooth surface finish.

There are a few international sophisticated equipment available in the market to check the surface roughness of thin films. They can measure the shape, depth and distribution of small pits on the film surface and scale the roughness as per the general roughness specification. However, these equipments are designed to scan very small portion of the film surface and costly. Our equipment can check the roughness of a reasonable area of the film (100*60 square millimeter area) and is directly calibrated as per the end use application (MPP capacitors field performance).

This product is basically a refracted light beam’s scattering extent measuring device, specially developed for measuring the extent of roughness on the BOPP film’s surface and provides detailed information in the electronic display.