1938 published the patent of epoxy resin, which laid a material foundation for the development of glass fiber electrical laminated materials.
1939 alkali-free glass fiber came out.
1942 unsaturated polyester was put on the market, and then it was found that the combination of glass and saturated ester could greatly improve the mechanical strength of polyester resin, which was the beginning of FRP industry. Since then, the FRP industry has been the main driving force for the development of the fiber industry.