Film insert molding enables one-step fabrication of plastic components with a decorated or functional surface. In this process, a polycarbonate film, decorated by screen printing on the reverse side, is high pressure formed and trimmed before being placed in an injection mold and back-injected.
Radio bezels, climate control panels, displays and touch pads are nowadays manufactured by combining printed electronics applications and film insert molding technology.
For these applications, black non-conductive colour shades are required for overprinting and protecting the metallic and polymeric conductive paste prints. The screen printings inks serve as adhesion promoter to bond the printed electronics film with the decorated film in a two-layer construction as well as to bond it with the back molding resin directly.
Carbon-based pigments, so called carbon blacks, normally used for black colour shades, are electrically conductive and can interfere with the functional structures.
Therefore, various non-conductive black colour shades have been developed for printed electronics applications with properties such as deep black, opaque, IR-transmitting, halogen free pigmented, hydrolysis resistant and with improved adhesion in compound values.
Besides other colour shades the following colour shades are the main products:
The newly developed one-component colour shade NORIPHAN® HTR N 990/010 NC has a deep black appearance and is non-conductive due to its formulation without carbon black. The NORIPHAN® HTR N 990/010 NC colour shade has been formulated and optimized regarding the interlayer adhesion and shows good adhesion in compound values in the final film/ink/injection material composition.
The deep black and opaquely formulated colour shade NORIPHAN® N2K 953 is processed as two-component system. This screen printing ink shows high electrical resistance in capacitive applications.
Both black colour shades can be used for overprinting conductive pastes and meet the increased requirements regarding thermal resistance, interlayer cohesion and the demanding hydrolysis test in the automotive industry.
To learn more about Pröll and their products visit their website here.