HECHT + DIEPER realized a tight encapsulation of an antenna inductor in a plastic backing plate by using the hot melt adhesive Macromelt. Hot melt molding based on polyamide offers a cheap alternative to traditional polyurethane or epoxy potting compounds in this example.
Unlike the classic plastic injection molding, processing of this hot melt happens at a significantly lower injection pressure.
The low injection pressure does have the advantage that electronic components can be directly over-molded without damaging them.
Hot melt adhesives are processed at temperatures between 180C and 240°C. They can be exposed to temperatures between -40°C to 140°C. The adhesion properties on PA, PBT or other polar plastics are very good.
Thermal casting materials of polyamides are also advantageous from an ecological point of view; since they are produced from renewable raw materials, no chemical reactions take place during processing and no solvents are released.