Thermoplastic polyurethane (TPU) is a versatile elastomer with a wide range of mechanical, environmental, and processing properties. Its performance characteristics make it suitable for applications ranging from soft films to high-strength mechanical components.
Mechanical Properties
TPU offers a broad hardness range, from Shore A 60 to Shore D 85, which can be adjusted by modifying the formulation-such as the ratio of isocyanate, polyol, and chain extender. This flexibility allows TPU to be used in a variety of applications, from soft films to rigid gears.
TPU exhibits high elasticity and tensile strength: elongation at break can reach 400%–800% or more, giving it rubber-like flexibility. Tensile strength typically ranges from 20–60 MPa, with some high-performance grades exceeding 70 MPa, outperforming many TPEs such as SEBS-based materials.
The material also provides excellent tear resistance, usually between 40–120 kN/m, making it ideal for applications that require crack resistance, such as sports equipment or conveyor belts. Its abrasion resistance is remarkable, often 3–5 times higher than natural rubber (Taber abrasion index as low as 50–100 mg), suitable for shoe soles, rollers, and seals.
Environmental and Weather Resistance
TPU demonstrates good temperature resistance: short-term service can range from –40°C to 120°C, with some modified grades capable of 130–150°C. For long-term use, TPU remains stable between –30°C and 80°C, outperforming most TPEs.
TPU is also resistant to oils and chemicals, including lubricants, fuels, and hydraulic oils, with performance superior to SEBS-based TPE. However, it is less resistant to strong acids and bases. Hydrolysis resistance differs between TPU types: polyether-based TPU shows better hydrolysis resistance for humid environments, while polyester-based TPU offers better oil resistance but may degrade under long-term water exposure.
Aging resistance varies by type. Aliphatic TPUs, such as polyether-based grades, resist UV and oxidation well and do not yellow easily, making them suitable for outdoor applications like cable sheaths. Aromatic TPUs have higher mechanical strength but are more prone to yellowing under UV exposure.
Processing Properties
As a thermoplastic, TPU can be processed via injection molding, extrusion, blow molding, and calendering without vulcanization, providing high production efficiency. Its melt viscosity is temperature-sensitive, with processing temperatures generally ranging from 180–230°C, depending on the grade. Careful temperature control is necessary to avoid degradation.
TPU is also compatible with many engineering plastics such as ABS and PC, allowing for overmolding and soft-hard composite structures, widely used in phone cases, automotive steering wheels, and other multi-material components.
Some TPU grades offer high transparency, particularly polyether-based and aliphatic types, with light transmittance up to 85%, suitable for optical devices and medical tubing.
TPU is environmentally friendly, halogen-free, and many grades comply with FDA and RoHS standards, making them suitable for food contact or medical applications like infusion sets and medical tubing.