マイクロテクスチュアリングによる異種ポリマーの接合技術とその展開

Abstract

Mobile cellular phones, tablets or smart meters required for a perfect water proof to prevent the electric circuit units or batteries from water permeability through joined interface between plastic cover cases. This paper was concerned with a flexible joining processing between two polymer cases via silicone rubber. Adaptive adhesion method was proposed to join the silicone ring-shaped rubber onto each plastic cover case with aid of micro-textures and tailored primer toward the perfect waterproof. The pico-second laser machining was utilized to make micro-texturing onto a mold die for injection molding of plastic case. Liquid injection molding system was also employed to make adaptive joining between the plastic case and silicone rubber during the molding. Tensile adhesive strength testing was performed not only to measure the load-displacement response during tensile loading but also to make real-time microscopic observation on the interfacial delamination. Effect of initial flaw on the adhesive strength was experimentally investigated with and without the micro-grooves. In particular, higher joining strength over 4 N/mm was attained with use of the skew-angled micro-grooves on the interface not only in the laboratory-scaled specimens but also in the practical joined parts. No leaks were detected in the highly pressurizing test over 15 kPa.