Examples of the main component include thermoplastic resins which are used in the field of composite materials, for example, polyolefin resins such as a polyethylene resin, a polypropylene resin and an ethylene-propylene copolymer; polycarbonate resins; polyester resins such as polyethylene terephthalate, polybutylene terephthalate and polybutylene naphthalate; polystyrene resins such as an acrylo