PBT is a milky white, semi-transparent to opaque, crystalline thermoplastic polyester. It boasts high heat resistance, toughness, fatigue resistance, self-lubrication, low friction coefficient, weather resistance, and low water absorption rate of only 0.1%, maintaining various properties (including electrical properties) in humid environments. It has excellent electrical insulation properties, but has high volume resistance and dielectric loss. It is resistant to hot water, alkalis, acids, oils, but is susceptible to halogenated hydrocarbons and has poor hydrolysis resistance. It can crystallize rapidly at low temperatures and has good molding properties. Its drawbacks include low notch impact strength and high shrinkage rate during molding. Therefore, most products are reinforced with glass fiber or inorganic fillers to enhance tensile and bending strength by more than double and significantly increase the heat deflection temperature. They can operate continuously at 140°C. However, after glass fiber reinforcement, the longitudinal and transverse shrinkage rates of the products are inconsistent, which can easily cause warping.