Thermoplastic polyester elastomer referred to as TPEE or COPE, is a class of linear block copolymers containing PBT (polybutylene terephthalate) polyester hard segment (crystalline phase) and aliphatic polyester or polyether (amorphous phase) soft segment. TPEE belongs to high-performance engineering grade elastomer, with high mechanical strength, good elasticity, impact resistance, creep resistance, cold resistance, bending fatigue resistance, oil resistance, chemical resistance and solvent erosion, etc., and has good processability, and can be filled, reinforced and alloyed modification, in automotive parts, hydraulic hoses, cables and wires, electronic and electrical appliances, industrial products, stationery, biological materials and other fields have been widely used. Solvent erosion and other advantages, has good processability, and can be filled, enhanced and alloyed modification, in automotive parts, hydraulic hoses, cables and wires, electronic appliances, industrial products, sports and cultural goods, biological materials and other fields have been widely used.

　　The physical and chemical properties of TPEE

　　Mechanical properties: Through the adjustment of the ratio of hard and soft segments, TPEE hardness can be changed from Shore D32 to D80, its elasticity and strength between rubber and plastic. Compared to other thermoplastic elastomers (TPEs), TPEE has a higher modulus at low strain conditions than other TPEs of the same hardness. When modulus is an important design condition, using TPEE can reduce the cross-sectional area of the product and reduce the amount of material used.

　　Tensile strength:Compared with polyurethane elastomer (TPU), TPEE compressive modulus and tensile modulus is much higher, with the same hardness of TPEE and TPU to make the same part, the former can withstand greater load. Above room temperature, TPEE bending modulus is high, suitable for making cantilever beams or torque type parts, especially suitable for making high temperature parts. TPEE low temperature flexibility, low temperature notch impact strength is better than other TPE, wear resistance and TPU equivalent. TPEE has excellent fatigue resistance, combined with high elasticity characteristics, making the material an ideal material for multiple cycle load use conditions, suitable for The production of gears, rubber rollers, flexible couplings, belts, etc.

　　Heat resistance performance: TPEE has excellent heat resistance, the higher the hardness, the better the heat resistance. TPEE has a very high temperature, can adapt to the automotive production line baking paint temperature (150-160 ℃), and it has a small loss of mechanical properties at high temperatures. Used above 120 ℃, TPEE tensile strength is much higher than TPU. in addition, TPEE also has excellent low-temperature resistance. the TPEE brittle point is lower than -70 ℃, and the lower the hardness, the better the cold resistance, most TPEE can be used under -40 ℃ for a long time. Due to the balanced performance at high and low temperatures, TPEE working temperature range is very wide, can be used in -70-200 ℃.

　　Chemical media resistance: TPEE has excellent oil resistance, at room temperature can be resistant to most polar liquid chemical media (such as acids, alkalis, amines and diols), and its ability to resist chemicals increases with its hardness. TPEE on most organic solvents, fuels and gases, the swelling resistance and resistance to permeability is good, the permeability to fuel is only neoprene, chlorosulfonated polyethylene, nitrile rubber and other oil-resistant The permeability to fuel is only 1/3-1/300 of neoprene, chlorosulfonated polyethylene, nitrile rubber and other oil-resistant rubber.

　　Weather resistance, aging resistance: TPEE in water spray, ozone, outdoor atmosphere and other external conditions, chemical stability is excellent. Like most thermoplastic elastomers (TPE), degradation occurs under the action of UV light (UV light below 310nm is a major factor in degradation), so for outdoor applications or products subject to sunlight conditions, UV protection additives should be added to the formula, including carbon black and various pigments or other shielding materials, phenolic antioxidants and benzotriazole-type UV shielding agent, and can Effectively prevent UV aging.

　　High resilience: The use of TPEE materials in springs provides a long service life and helps trains start, accelerate, decelerate and stop smoothly. Unlike metal springs, they do not rust, deteriorate under natural conditions, or break or lose elasticity. Compared to rubber, it has greater reusability and maintains good elasticity.

　　Processability: TPEE has excellent melt stability and full thermoplasticity, so it has good processability and can be processed using a variety of thermoplastic processes, such as extrusion, injection, blow molding, rotational molding and melt casting molding. At low shear rates, TPEE melt viscosity is not sensitive to shear rate, while at high shear rates, melt viscosity decreases with increasing shear rate. As the TPEE melt is very sensitive to temperature, within 10 ℃ change, its melt viscosity changes several times to dozens of times, so the molding should be strictly controlled temperature.