Poly (butylene terephthalate), also known as poly (tetramethylene terephthalate). English name; Polybutyleneterephthalate。 PBT, pbtp or ptmt for short, is a condensation polymer of p-benzoic acid and 1,4-butanediol. It can be prepared by ester exchange or direct esterification through polycondensation. The development trend in the future is direct esterification. Together with pet, PBT is called thermoplastic polyester.

The main chain of PBT is composed of saturated linear molecules connected by rigid benzene ring and flexible aliphatic alcohol. The high geometric regularity and rigid part of the molecules make the polymer have high mechanical strength, outstanding chemical resistance, heat resistance and excellent electrical properties; There is no side chain in the molecule, and the structure is symmetrical, which meets the requirements of close stacking, so the polymer has a high crystalline form and high melting point. The molecular structure determines that PBT has good comprehensive properties. PBT is a kind of engineering plastics with the latest industrialization and the fastest development. The reason why PBT has become a rising star of engineering plastics is that it has excellent comprehensive properties, good molding processability and performance / price comparison. Therefore, although PBT was industrialized in the 1970s, it soon sold well in the market, and now it is one of the five engineering plastics with the fastest development.

1. Excellent mechanical properties, high mechanical strength, good fatigue resistance and dimensional stability. Creep is also small, and these properties change little at high temperature.

2. The energy consumption of PBT is the lowest among engineering plastics, which is of great significance in the case of energy shortage in the world.

3. Excellent heat aging resistance, enhanced UL temperature index up to 120 ~ 140 ℃, in addition, outdoor long-term aging is also very good.

4. Good solvent resistance and no stress cracking.

5. PBT is easy to be flame retardant, up to UL94V-0. Due to its good affinity with flame retardant, it is easy to develop reactive or additive flame retardant grade. Flame retardant products are widely used in electronic and electrical industry.

(3) PBT is easy to decompose in water, so it should be used cautiously in high temperature and humidity environment.

Excellent electrical performance, high volume resistivity and dielectric strength, excellent arc resistance, little moisture absorption, and stable electrical performance in humid and high temperature environment. It is an ideal material for manufacturing electronic and electrical parts.

8. Easy molding and secondary processing, easy injection molding or extrusion with ordinary equipment. Because of its high crystallization speed, good fluidity and lower mold temperature than other engineering materials, it only takes a few seconds to process thin-walled parts and 40-60s for large parts.

PBT Chinese name polybutylene terephthalate, referred to as saturated polyester, is a high crystalline thermoplastic.

Advantages: 1. Stable mechanical properties, tensile strength is similar to tensile modulus and nylon; 2. The friction coefficient is small and self-lubricating;

3. The water absorption is low; 4. Excellent electrical properties; 5. Good dimensional stability; 6. The drug resistance and oil resistance are excellent.

Uses: 1. Electronic and electrical appliances: fusible wire breaker, electromagnetic switch, flyback transformer, household appliance handle, connector, shell, etc;

2. Car: door handle, bumper, distributor cover, mudguard, wire cover, wheel cover, etc;

3. Industrial parts: OA fan, keyboard, fishing tackle reel, parts, lampshade, etc.

Features: PBT is milky translucent to opaque, crystalline thermoplastic polyester. It has high heat resistance, toughness, fatigue resistance, self lubrication, low friction coefficient, weather resistance, low water absorption, only 0.1%. It still maintains various physical properties (including electrical properties) and electrical insulation in humid environment, but has large dielectric loss. It is resistant to hot water, alkali, acid and oil, but it is easy to be eroded by halogenated hydrocarbon and has poor hydrolysis resistance. It can crystallize rapidly at low temperature and has good formability. The most suitable processing method is injection molding. Other methods include extrusion, blow molding, coating and various secondary processing molding. Before molding, it needs to be pre dried, and the moisture content should be reduced to 0.02%. PBT (reinforced and modified PBT) is mainly used in automobile, electronic appliance, industrial machinery, polymer alloy and blending industry. Such as distributor, body parts, igniter coil framework, insulation cover, exhaust system parts, motorcycle igniter, deflection coil of TV, picture tube and potentiometer bracket, sound output transformer framework, adapter framework, switch connector, electric fan, refrigerator, washing machine motor end cover, shaft sleeve in electronic and electrical industry