example at least one kind of material selected from a group consisting of: metal, porcelain, glass, paper; polyolefin series resin such as polyethylene, polypropylene, and polybutene; polyester series resin such as polymethacrylate series resin, polycarbonate series resin, polyethylene terephthalate, and polybutylene terephthalate; and polyamide series resin, are used as the constituting materials