Polyester and TDI high-performance polyurethane prepolymer, hardness 85A, 94A
PTMEG and TDI high-performance polyurethane prepolymer, hardness 85A, 94A
Differences between PTMEG Prepolymer and Polyester Prepolymer 95A
Packing: 200kgs/drum
1. Fundamental Structural Differences
- PTMEG Prepolymer (Polyether Type): Its soft segment is a polyether chain with repeating unit -O-(CH₂)₄- . The main chain contains ether bonds (-O-), synthesized via ring-opening polymerization of tetrahydrofuran.
- Polyester Prepolymer (Polyester Type): Its soft segment is a polyester chain with repeating unit -COO-(CH₂)ₙ- . The main chain contains ester bonds (-COO-), produced by polycondensation of dibasic acids and diols.
2. Key Property Comparison
- Hydrolysis resistance: PTMEG – Excellent (stable ether bonds, service life over 10 years in water); Polyester – Poor (ester bonds prone to hydrolysis, 3–5 years in humid environments).
- Low-temperature toughness: PTMEG – Outstanding (glass transition temperature ≈ -80 °C, remains flexible at -30 °C); Polyester – Poor (brittle below -20 °C).
- Mechanical strength: PTMEG – Moderate; Polyester – High (superior tensile strength, wear resistance and tear resistance).
- Oil & solvent resistance: PTMEG – Average; Polyester – Excellent (resistant to engine oil and non-polar solvents).
- Elasticity & resilience: PTMEG – Excellent (fast rebound, permanent deformation < 5%); Polyester – Good.
- Heat & aging resistance: PTMEG – Good resistance to ozone and mildew; Polyester – Superior thermal stability and oxidation resistance.
3. Synthesis & Processing Characteristics
- PTMEG Prepolymer: Linear structure, narrow molecular weight distribution (PDI: 1.05–1.2), low viscosity and easy processing. Waxy at room temperature, turns transparent liquid when heated.
- Polyester Prepolymer: Higher viscosity, broader molecular weight distribution and slightly higher acid value. Strict moisture control is required to prevent hydrolysis; generally presented as viscous liquid.
4. Typical Applications
- PTMEG Prepolymer: Spandex fibers, low-temperature sealing parts, fire hoses, underwater cables, outdoor elastomers.
- Polyester Prepolymer: High-wear shoe soles, conveyor belts, rollers, sealing parts, FDA-compliant food-contact components.
5. Summary
PTMEG prepolymer features outstanding hydrolysis resistance, low-temperature flexibility and high resilience. Polyester prepolymer delivers high mechanical strength, excellent wear & oil resistance and good thermal stability. and TDI high-performance polyurethane prepolymer, hardness 85A, 94A