TPU Elastomer: Key Benefits and Advantages
TPU (thermoplastic polyurethane) is a versatile material as it offers flexibility, durability, and resistance to abrasion and chemicals.
Manufacturing for TPU Parts
About TPU Options
For injection molding, we offer two TPU formulations: Texin 245D and Texin 983A. 3D printing offers TPU with a hardness of 70-A.
Texin 245D (injection molding) resin is an aromatic polyester-based thermoplastic polyurethane with a Shore hardness of approximately 43D. It is both impact- and chemical-resistant. The natural color version complies with FDA food-contact regulations.
Texin 983A (injection molding) is a flexible resin that offers outstanding abrasion-, impact-, moisture-, and chemical-resistance. It complies with FDA food-contact regulations. It’s Shore hardness value is 83.
TPU 70-A (3D printing) is a thermoplastic polyurethane (TPU) that combines rubber-like elasticity and elongation with good abrasion-, wear-, and impact-resistance. You can leverage it to produce both prototypes and functional parts. The “70-A” refers to its Shore hardness.
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.
Food grade: Texin 245D in its natural color and Texin 983A are both considered food grade resins.
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
Sometimes TPU might not be the best choice for your application. Here are the major reasons why:
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 molding 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.
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 Molding
This is the smart way to go if you need production quantities of your TPU part, using one of the two Texin resins 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 molding. 3D printing is also available for low-volume production.
Applications for TPU Components and Parts
TPU is used to produce a wide range of products, such as:
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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:
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| Material | Flexibility | Durability | Temperature Range | Chemical Resistance | Applications | Advantages | Disadvantages |
|---|---|---|---|---|---|---|---|
| COPE | Moderate to high | Excellent tensile strength | Moderate to good (-40°F to 248°F) | 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 (-58°F to 482°F) | Excellent | Medical devices, baby products | Stability over a wide temperature range | Higher cost, more complex processing |
| PEBA | High | High durability | Wide (-40°F to 284°F) | 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 (-76°F to 356°F) | 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°F to 158°F) | 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°F to 176°F) | 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 (-76°F to 275°F) | 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 characterized 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
