Resin case in which gas-permeability and waterproof quality are compatible, and die for manufacturing such case

A method of manufacturing a sealed resin case for housing equipment, comprising:

• providing a first die having an inner surface and an annular protrusion on said inner surface, said annular protrusion surrounding and defining a recess, and a second die having a cylindrical protrusion receivable in said recess of the first die and having a diameter such that an annular space is provided between said cylindrical protrusion of the second die and said annular protrusion of the first die when the cylindrical protrusion is received in said recess of the first die;
• setting a film which is permeable to gases but impermeable to liquids in said recess of said first die;
• closing said first and second dies to form a mold cavity having a shape corresponding to that of at least a part of a resin case to be formed, said mold cavity including said annular space, and, while closing said first and second dies, causing said cylindrical protrusion to enter said recess of the first die and hold at least a part of a central region of said film between said cylindrical protrusion of the second die and a part of the inner surface of the first die within said recess of the first die, while allowing a peripheral region of said film to extend radially outward with respect to said cylindrical protrusion into said annular space between said cylindrical protrusion and said annular protrusion;
• injecting molten resin into said mold cavity to form said at least a part of a resin case, and causing said film to be integrally connected to said at least a part of the resin case by heat and/or pressure applied through said molten resin to said peripheral region of said film.