"The first structural body 10 is formed using a plastic material such as PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PES (polyethersulfone), polypropylene, polypropylene sulfide, polycarbonate, polyether imide, polyphenylene sulfide, polyphenylene oxide, polysulfone, polyphthalamide, acrylic, or polyimide, or an insulating material such as nonwoven fabric, or paper." . . . .