@spot_material
hello@spotmaterial.com
Thermoplastic polyurethane (TPU)
2-15 usd/kg
Thermoplastic polyurethane (TPU) has the characteristics of both plastic and rubber. Unlike polyurethane resin (PUR), it is a melt-processable thermoplastic elastomer (TPE), which means it can be injection moulded, extruded and recycled. This makes it easier to process than thermosetting material. It is durable, flexible, strong and suitable for demanding applications in automotive, sports and textiles. Examples range from colourful moulded shoe soles to industrial non-marking caster wheels.
As with PUR, it is built by mixing a polyol with diisocyanate. There are two main types of TPU: polyester- and polyether-polyol based. This defines the flexible part of the polymer, and the diisocyanate the rigid part. The most commonly used diisocyanate for TPU is methylene diisocyanate (MDI). While polyester types offer superior abrasion resistance, heat resistance and gas permeability (film applications), polyether TPU gives better low temperature flexibility, water resistance and microbial resistance. A third group is based on polycaprolactone (PCL), which combines the toughness and resistance of polyester types with improved low temperature performance and water resistance.
By varying the type and ratio of these blocks, the physical properties of the TPU can be tailored to a range of applications. An advantage of this polymer structure, compared to polyvinyl chloride (PVC) for example, is that it does not require a plasticiser to be flexible. Plasticiser can migrate to the surface over time, reducing the elastomeric effect and potentially releasing hazardous substances.
TPU can be further divided into aromatic (closed rings of atoms) and aliphatic (straight or branched chains of atoms) types. Aromatic TPU are based on MDI and the most common. They are used in applications that require flexibility, strength and toughness. Aliphatic TPU offer superior resistance to UV, colour fading and offer exceptional optical clarity.
It is possible to produce partially bio-based TPU, by replacing one of the elements with prepolymer derived from biomaterial. An example is Apilon by Trinseo.
Log in to search similar materials
Log in to find better material
Sustainability concerns
Non-renewable ingredients
Raw material generates polluting by-products
Low circularity potential
Potentially toxic in use
Microplastics
Thermoplastic polyurethane (TPU) is converted into an elastic and durable fibre and textile suitable for fashion, footwear, automotive and industrial applications. It is also known as spandex, and Lycra. It provides a good alternative to polyvinyl chloride (PVC), but will be more expensive.
It is produced as yarn in mono-filaments or bi-component filaments. While the most common method of production is from chemical solution, it is possible to melt spin TPU, which reduces volatile organic compounds (VOC). In addition, melt spun yarns have an especially soft touch and feel on the skin. TPU repels water and dirt, which are useful attributes for demanding applications such as bags, sports gear, tight fitting clothing and truck covers. In fashion and apparel, it known as Spandex, Lycra and elastane.
TPU nonwoven fabrics, produced as meltblown or spunbond, have a highly breathable mesh structure. This makes them well suited to sports and leisure wear, where their stretch and recovery sets them apart from conventional nonwovens produced from polypropylene (PP) or polyethylene terephthalate (PET), polyester.
TPU synthetic leather is produced by extruding multiple layers of the material and embossing it with a leather like grain to suit the application. It is combined with a layer of foam, in expanded TPU (ETPU), to create a strong and lightweight material. It is available in a range of grains and colours, and is suitable for automotive interior, furniture upholstery, consumer products, footwear, apparel and fashion accessories. As a monomaterial solution, it can be recycled end of life.
