The reinforcement materials composed of glass fiber cloth, chopped strand felt, continuous strand felt, untwisted roving fabric, and untwisted roving in a certain order are generally as follows:

(1) Short cut raw silk felt+untwisted roving fabric

(2) Short cut strand felt+untwisted coarse gauze+short cut strand felt

(3) Short cut strand felt+continuous strand felt+short cut strand felt

(4) Short cut raw felt+random untwisted roving

(5) Short cut raw silk felt or cloth+unidirectional untwisted roving

(6) Short cut strand+surface felt

(7) Glass fiber cloth+unidirectional untwisted roving or glass rod+glass fiber cloth