Unsaturated polyester resin can be defined as a viscous liquid formed by polycondensation of diacid and diol, in which linear polymers compound containing unsaturated diacid or diol is dissolved in monomer (usually styrene). 1. raw materials: phthalic anhydride (gan), maleic anhydride, propylene glycol, ethylene glycol and ethylene propylene 2. Downstream applications: (1) The glass fiber reinforcement field (FRP) accounts for 55% to 60% of the total. Glass fiber reinforced plastic (FRP) is made of glass fiber and unsaturated polyester resin. Its main products are applied to vehicle shell, wind power and other fields (2) Casting field: accounting for 25% to 30% of the total, artificial stone and handicraft buttons (3) Coating field: accounting for 10% of the total amount, applied to gel coat, marble glue, floor and coating (unsaturated paint) 3. Others (1) in 2009, the national quality inspection bureau began to implement industrial license for UPR industry, sampling products, and unqualified products are not allowed to be generated (2) The annual production capacity of small-scale unsaturated polyester resin manufacturers is only a few thousand tons, and the annual output of large-scale unsaturated polyester resin manufacturers is more than 100,000 tons; Small-scale manufacturers have poor equipment, backward production process control means and unstable product quality, and can only produce low-end general-purpose resins. Manufacturers with production capacity of over 30,000 tons have relatively sophisticated equipment, advanced production process control means and stable product quality.