Gas-permeable plug and method for manufacturing the same

摘要

A gas-permeable plug adapted to be inserted in an insertion hole (H0) formed through a part of a casing (C) in an inward-outward direction, comprising a plug body (B) and a permeable sheet (S1) including therein countless minute permeable pores (33) wherein the plug body (B) is injection molded from a material having rubber-like elasticity and the permeable sheet (S1) is integrally bonded to a sheet bonding portion (13) by an anchor operation such that when the plug body (B) is injection molded, at the sheet bonding portion (13), part of a heat-melted liquid resin enters the minute permeable pores and/or the permeable gaps in irregular directions by injection molding pressure and is solidified.