TPU: Understanding Thermoplastic Polyurethane
Thermoplastic polyurethane, commonly known as TPU, is a versatile material that combines many of the useful characteristics of rubber and plastic. It is flexible and resilient, yet can be processed using thermoplastic manufacturing methods. These qualities make TPU suitable for products that need to withstand repeated movement, wear or impact.
What is TPU?
TPU is a type of thermoplastic elastomer (TPE). Like other thermoplastics, it softens when heated and can be shaped, then becomes solid again as it cools. This behaviour allows it to be processed using techniques such as injection moulding, extrusion and blow moulding. Unlike many conventional rubbers, TPU can often be reprocessed, subject to the material grade and the quality of the recovered material.
TPU is made by combining chemical building blocks that form polyurethane chains. Its formulation can be adjusted to produce different levels of hardness, flexibility and performance. As a result, TPU is available in a wide range of grades for different applications.
Key properties of TPU
The exact performance of TPU depends on its formulation, but common properties include:
- Flexibility and elasticity: TPU can bend and stretch, and many grades recover their shape after deformation.
- Abrasion resistance: It is often used in components exposed to rubbing and surface wear.
- Toughness: TPU can resist impact and repeated flexing in suitable applications.
- Oil and grease resistance: Some grades offer useful resistance to oils, greases and other substances.
- Transparency and colour options: Certain grades can be clear or produced in a range of colours.
- Processability: TPU can be shaped using established thermoplastic processing equipment, with conditions selected for the particular grade.
Not every TPU grade has the same properties. Resistance to heat, sunlight, chemicals and moisture can vary, so material selection should be based on the product’s operating conditions.
How TPU is processed
TPU is commonly supplied as pellets. Depending on the grade and product design, manufacturers may use injection moulding to make shaped parts, extrusion to produce profiles or tubing, and blow moulding for certain hollow products. TPU can also be used in film production and additive manufacturing.
Good processing practice matters. Many TPU grades need to be dried before use because moisture can affect processing and the quality of the finished product. Manufacturers should follow the supplier’s guidance on drying, temperature, equipment settings and storage.
Where is TPU used?
TPU’s combination of flexibility, durability and processability supports a wide range of uses, including:
- Footwear soles, protective layers and flexible components
- Wheels, rollers, belts and other wear-resistant parts
- Protective cases, films and surface coverings
- Automotive interior and exterior components
- Flexible hoses, cables and tubing
- Sports equipment and consumer products
- Selected medical and healthcare products, where a suitable, compliant grade is specified
These examples are not interchangeable: each application requires a TPU grade that meets its mechanical, chemical, regulatory and environmental requirements.
Choosing the right TPU grade
When selecting TPU, product designers and manufacturers should consider the forces the component will experience, the required flexibility and hardness, and its exposure to heat, sunlight, oils, cleaning agents or moisture. Other factors may include transparency, colour, surface finish, processing method and relevant safety or regulatory requirements.
It is also important to test the selected grade in the finished product. Design, processing conditions and the surrounding environment can all affect performance. A material supplier can help identify suitable grades and provide technical data for evaluation.
TPU and sustainability
Because TPU is a thermoplastic, production scrap and some post-industrial material may be suitable for reprocessing, depending on the grade, condition and intended use. Recycling options for used products can be more challenging when they contain mixed materials, coatings or components made from different polymers.
Improving the sustainability of a TPU product may involve designing it for longer service life, reducing material use, simplifying its construction and exploring appropriate recycling routes. Claims about recycled content or recyclability should be verified for the specific product and local waste-management arrangements.
Conclusion
Thermoplastic polyurethane is a flexible and adaptable material that can offer a useful balance of elasticity, toughness and wear resistance. Its broad range of grades and processing options makes it valuable across many industries. Careful selection, correct processing and application-specific testing are essential to achieve reliable performance.
5 Essential Tips for Choosing, Processing and Storing TPU (Thermoplastic Polyurethane)
- Choose the right TPU grade for your needs
- Check chemical and temperature resistance before use.
- Dry TPU pellets before processing to reduce defects.
- Use suitable settings for printing or moulding.
- Store TPU in a cool, dry place away from sunlight.
Choose the right TPU grade for your needs
Choose the right TPU grade for your needs by considering how the finished product will be used and the conditions it must withstand. TPU grades vary in hardness, flexibility, abrasion resistance and resistance to heat, sunlight, oils and moisture. Check that the grade suits your manufacturing process and any applicable safety or regulatory requirements, and test it in the finished product before full-scale production. A material supplier can help identify suitable options.
Check chemical and temperature resistance before use.
Before using TPU (thermoplastic polyurethane), check that the selected grade can withstand the chemicals and temperatures it will encounter. Resistance can vary between formulations, and exposure to oils, solvents, cleaning agents, heat or cold may affect the material’s strength, flexibility or service life. Review the manufacturer’s technical data and test the TPU under the intended conditions to help ensure reliable performance.
Dry TPU pellets before processing to reduce defects.
Dry TPU pellets before processing to help prevent moisture-related defects in the finished product. Moisture can cause issues such as bubbles, surface marks or reduced material strength during moulding or extrusion. Follow the supplier’s recommended drying temperature and duration for the specific TPU grade, and store dried pellets in a sealed container to limit moisture absorption.
Use suitable settings for printing or moulding.
Use processing settings suited to the specific TPU grade and equipment when printing or moulding. Check the manufacturer’s guidance for temperature, speed, pressure and cooling, and dry the material beforehand if recommended, as moisture can affect the finish and part quality. Fine-tune settings with trial runs to achieve consistent results.
Store TPU in a cool, dry place away from sunlight.
Store TPU (thermoplastic polyurethane) in a cool, dry place, away from direct sunlight and sources of heat. Excessive warmth, moisture and prolonged exposure to UV light may affect the material’s properties and make it harder to process. Keep TPU in its original, sealed packaging until use, and follow the supplier’s storage recommendations to help maintain its quality.