Encapsulation of electronic components with thermoplastic coatings - using low viscosity wax to seal a resin base coating of high viscosity

摘要

Electronic components, esp. capacitors are encapsulated by a combination of a coating of rigid thermoplastic material (I) applied in a molten state and an overlay of a sealant (II) applied as a relatively fluid melt, e.g. a molten wax, esp. at coating interfaces with e.g. protruding terminals. (I) is pref. cellulosic, polyamides, polydiene, polyepoxide, polyester or polyvinyl resin. The coating materials are less expensive than conventional thermosetting potting resins and are relatively neutral chemically, i.s. do not involve acidic or alkaline intermediates which may corrode metallic components.