Composite materials are materials that, after mixing two or more types of materials, physically and chemically make each material maintain its original image and achieve superior performance to the original material. It is a representative new material widely used in aerospace, space, automobiles, railway vehicles, ships, defense products, sporting goods and construction materials. In particular, plastics reinforced with various high strength fibers such as carbon fiber, boron fiber and kevlar fiber are extensively used in airplanes, missile bodies, rocket motor cases, luxury tennis racquets, skiing, golf clubs and the like.