TPU Elastomer

TPU (thermoplastic polyurethane) is a versatile material as it offers flexibility, durability, and resistance to abrasion and chemicals

Protolabs TPU Capabilities 

Manufacturing with TPU

TPU parts can be produced using various manufacturing processes. The ideal production method is determined by quantity needed, geometry, and the desired properties of your part. Some common methods include:

Injection Moulding

This is the smart way to go if you need production quantities of your TPU part, using one of the two Pearlthane resins (Pearlthane 11T85, Pearlthane 11T95P) mentioned earlier.

3D Printing

Using 3D printing offers the chance to prototype parts without paying for tooling. Once you have a part that satisfies your requirements for form, fit, and function you can move on to higher quantities, which are often handled using injection moulding. 3D printing is also available for low-volume production.

 

Advantages and Disadvantages of TPU

Advantages of TPU 

  • Abrasion resistance: Due to its elasticity, TPU parts have the ability to deform under stress and return to their original shape, rather than abrade.
  • Biocompatibility: TPU can be used for medical supplies such as catheters, medical tubing, wearables, and wound dressings. Note that not all formulas of TPU are biocompatible. 
  • Chemical resistance: The molecular structure of TPUs includes pseudo- crosslinked polymer chains, which enhance chemical resistance. This resistance extends to acids, alkalis, and other harsh chemicals.
  • Elasticity: As a block copolymer, TPU alternates hard and soft segments. The hard segments help with rigidity, strength, and durability, while the soft segments are made up of long, flexible chains that can easily uncoil and stretch when a force is applied. This structure also allows for TPU to return to its original shape when the force is removed. 
  • Soft touch: All three of the variants of TPU that we offer feel soft when touched, due to those previously mentioned "soft segments". 

 

Disadvantages of TPU 

  • Finishing difficulty: The surface requires preparation such as cleaning and mild abrading to ensure good adhesion. Solvent-based finishing products might not bond well. In terms of longevity of the finish, flexibility might work against you if the finish is rigid. In worst-case scenarios, it might even cause cracks and peeling.
  • Lack of rigidity: Fundamentally the issue here is that it is difficult to achieve structural integrity with certain geometries using TPU. As with any part, design is crucial, including uniform wall thickness, use of fillets, and more. On the injection moulding side, note that lack of rigidity can cause issues with ejection of your parts.
  • Printing accuracy/quality: While many choose TPU for its flexibility, that same characteristic can cause less precise printing compared to other materials, including warping and dimensional accuracy issues.
  • Prone to moisture absorption: The chemical structure is the prime culprit here. TPU’s polymer chains have spaces that allow for moisture to penetrate, and the urethane links tend to be hygroscopic, attracting water along the surface.

 

Applications of ABS

TPU’s balance of flexibility, durability, chemical resistance, and comfort makes it a versatile choice across industrial, medical, and consumer products. It bridges the gap between rigid plastics and soft rubbers, enabling both functional and ergonomic designs.

 

Industry Applications Why TPU is Suitable
Automotive Flexible couplings, gaskets and seals, hydraulic and fuel hoses, protective cable sleeves, tubing for fluid and air systems High elasticity for tight seals, abrasion and wear resistance, oil, grease and chemical resistance, flexibility and kink resistance
Medical Catheters, flexible connectors, medical-grade tubing, seals in pumps, syringes and valves Biocompatibility (medical grades), hydrolysis and sterilization resistance, transparent grades for flow visibility, consistent performance under fluid exposure
Consumer / Wearables Sports bands, fitness trackers, smartwatch straps, shoe soles and midsoles, overmolded grips for tools and equipment Comfortable for skin contact, sweat and abrasion resistance, energy absorption and rebound, soft-touch slip-resistant surface
Industrial Pneumatic hoses, fluid transfer tubing, seals in pumps and valves, cable sleeves for equipment protection High tear resistance, long-term durability under mechanical stress, chemical resistance, flexible yet strong in harsh condition

Comparing Materials Similar to TPU 

There are several materials that are similar to TPU in terms of their properties and applications. These materials are commonly used for their elastomeric properties, but they each have distinct characteristics: 

 

Material Flexibility Durability Temperature Range Chemical Resistance Applications Advantages Disadvantages
COPE Moderate to high Excellent tensile strength Moderate to good (-40°C to 120°C) Good to excellent Automotive parts, electric/electronic applications High elasticity, excellent mechanical properties Comparatively less flexible than TPU
Liquid Silicone Rubber Very high Excellent Wide (-50°C to 250°C) Excellent Medical devices, baby products Stability over a wide temperature range Higher cost, more complex processing
PEBA High High durability Wide (-40°C to 140°C) Good  Sport equipment, medical devices, consumer goods Excellent flexibility and impact resistance More expensive than TPU, TPO
SBC High Moderate Moderate Limited Packaging, personal care products, toys Soft touch Limited to low-stress applications
Silicone Very high Excellent wide (-60°C to 180°C) Excellent Medical devices, kitchenware, electronics Heat and cold resistance, flexibility Higher cost, lower tensile strength
TPO  Moderate Moderate, prone to degradation over time Moderate (-40°C to 70°C) Moderate to good  Automotive, roofing, door panels Cost-effective and durable Lower end of temperature- and chemical- resistance
TPU High  Excellent, abrasion-resistant Moderate (-40°C to 80°C) Good  Automotive, footwear, sports equipment Abrasion- and tear- resistance, flexibility Limited temperature range compared to silicone
TPV Moderate to high Good, with improved chemical resistance Wide (-60°C to 135°C) Good to excellent Automotive sealing, gaskets, construction Combines elasticity with heat resistance Typically, more expensive than TPO

Key Takeaways

  • COPE provides excellent tensile strength and mechanical properties, suitable for automotive and electronic applications
  • PEBA is characterised by its excellent flexibility and impact resistance, often used in sports and medical devices
  • SBC is known for its soft touch and is typically used in low-stress applications like toys and personal care products
  • TPO is cost-effective and durable but has lower temperature- and chemical- resistance compared to others
  • TPU is known for its excellent flexibility and abrasion resistance, making it suitable for durable applications
  • TPV provides a good balance of elasticity and heat resistance, making it suitable for automotive applications
  • True Silicone and liquid silicone rubber are ideal for products requiring extreme temperature stability and are extensively used in the medical and cooking industries