We explored a novel design-for-recycling method for encapsulated printed electronics in an injection-molded package that improves disassembly at End-of-Life (EoL). To this end, a non-adhering disassembly layer (NADL) was applied onto the printed circuitry and light-emitting diodes prior to injection molding. Surprisingly, the devices with a disassembly layer remained fully functional after injection molding, despite exposure to high shear forces and elevated temperatures. Facilitating the disassembly of an encapsulated electronic device using a weak link in the adhesion strength of the overmolded encapsulant invokes a contradiction: the possibility to remove the injected plastic from any underlying coating goes against the requirement of high adhesion over the entire surface area for structural strength and integrity during the harsh conditions expected by industry. To achieve balance between disassemblability and reliability, the adhesion strength of the overmolded encapsulant was tuned using vias in the coating design. To the author's best knowledge, this is the first time design-for-recycling principles were successfully applied to such in-mold structural electronics devices. Accelerated lifetime tests at 85 °C/85% relative humidity for 1000 consecutive hours were conducted to study the reliability of devices realized with this design-for-recycling method. Mechanical disassembly of molded devices proceeded uniformly along the intended interface of NADL with molded polycarbonate resin and exposed the printed Ag and surface-mounted components, thereby demonstrating the possibility to perform subsequent and dedicated recycling on plastics and metals separately.

中文翻译：

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塑料嵌入式印刷电子产品的拆卸

我们探索了一种新颖的回收设计方法，用于将印刷电子封装在注塑包装中，从而改善报废 (EoL) 时的拆卸。为此，在注塑之前将非粘合拆卸层 (NADL) 应用到印刷电路和发光二极管上。令人惊讶的是，尽管暴露在高剪切力和高温下，具有可拆卸层的装置在注射成型后仍保持完全功能。利用包覆成型密封剂粘合强度的薄弱环节来促进封装电子设备的拆卸会引发矛盾：从任何底层涂层中去除注射塑料的可能性违背了整个表面区域的高粘合力对结构强度的要求和在工业预期的恶劣条件下的完整性。为了实现可拆卸性和可靠性之间的平衡，在涂层设计中使用通孔来调整包覆成型密封剂的粘合强度。据作者所知，这是首次将回收设计原则成功应用于此类模内结构电子设备。我们在 85 °C/85% 相对湿度下进行了连续 1000 小时的加速寿命测试，以研究采用这种回收设计方法实现的器件的可靠性。模制设备的机械拆卸沿着 NADL 与模制聚碳酸酯树脂的预期界面均匀地进行，并暴露出印刷的 Ag 和表面安装的组件，从而证明了分别对塑料和金属进行后续和专门回收的可能性。