The glass fiber for reinforcement of rubber product is obtained by first twisting the coated glass fiber to obtain the twisted yarn and then carrying out an intertexture of two or more twisted yarns. 次いで、この被覆ガラス繊維を下撚りして下撚り糸を得て、この下撚り糸の2本以上を合せつつ上撚りしてゴム製品補強用ガラス繊維を得る。 - 特許庁