What is TPU Material?
Thermoplastic polyurethane, better known as TPU, is a thermoplastic elastomer that is a blend of rubber and plastic. TPU material is tough, flexible, durable and resistant to abrasions like oils and lubricants. The unique blend of rubber and plastic makes it suitable for various applications in automotive, sports, and textile coatings, breathable films, etc.
TPU rubber or plastic( yes, you can call it both) provides some extraordinary benefits because of its thermoplastic nature – great load-bearing capacity, high elongation at break, and fantastic tensile strength.
The blended material can be utilized as soft engineering plastic and soft rubber—the different ranges of inbuilt hardness(Shore 30A – Shore100A).
TPU material is also used as a premium additive for other thermoplastics like Polycarbonate and ABS to improve their tensile strength. A composite of TPU and ABS or PC will have a flexural modulus of upto 150000 psi. However, TPU has a tensile strength of around 5076 psi (for Shore 70A).
Here is a list of the largest TPU suppliers in the world
|Huntsman||IROGRAN®, KRYSTALFLEX®, AVALON®||United States|
|PolyOne||NEUSoft™, OnFlex™, Edgetek™, Gravi-Tech™,||United States|
|DowDuPont||DIPRANE™, HYPERLAST™||United States|
|Lubrizol||Pearlbond™, Isoplast®, Pearlstick™, Estane®||United States|
|Epaflex||EPAMOULD, EPACOL TK, EPALINE||Italy|
How is TPU Plastic Made?
The three basic raw materials for TPU are:
- A polyol or long-chain diol
- A chain extender or short-chain diol
- A diisocyanate
TPU plastic is produced by reacting a diisocyanate and one or more diols with each other in a particular way. It is a straightforward segmented block polymer made up of soft and hard segments.
Hard Segment: It is composed of a chain extruder and an isocyanate making TPU tough, rigid and producing its physical performance properties.
Soft Segment: It is constructed from a polyol and an isocyanate and gives TPU material its flexibility and elastomeric characteristics.
Main Properties of TPU Rubber/Plastic –
Here I will try to explain the properties in detail. Let’s begin:
- Optimum Comfort
- Scratch Resistance
- UV Resistance
- High Transparency with Abrasion Resistance
- Compatibility with ergonomic Applications
1. Optimum Comfort:
TPU filament provides optimum comfort for customers using sportswear, footwear, buildings, and construction materials. It is believed to highly breathable. If the customers prefer comfort over cost, then TPU is an ideal choice.
Multiple grades should be utilized depending on the comfort range and quality. Grades with values as high as 10,000 g./m2/day (+560%) are considered the best. Typical TPU has a vapor transmission below 1 500 g./m2/day.
Traditional TPU material can be modified with breathable ones to tune up the breathability according to the needs.
2. Scratch Resistance:
When the priority is scratch/abrasion resistance, thermoplastic polyurethane must be preferred over any thermoplastic materials. Thanks to that ability, TPU plastic becomes an integral part of automotive, industrial applications, sports, leisure, and wires and cables.
The scratch resistance of a material is decided by measuring the weight loss of a product in a standardized wear test, and TPU ranks the way above all the mainstream thermoplastics, making it the best.
3. UV Resistance:
Aliphatic TPU’s maintains good color stability to your aesthetic parts. They exhibit tremendous resistance to UV radiation coupled with great color stability while not compromising necessary mechanical properties.
Looking at the aliphatic TPU, the characteristics and compliance make it perfect for electronic applications. Organizations can bank on their scratch and UV resistance properties for all colored products.
4. High Transparency with Abrasion Resistance:
Clear and translucent TPU with good hardness is readily available in the market. That makes it applicable in producing transparent films and tubes through extrusion or even in injection molding technical aesthetic or glossy parts where transparency and thickness of up to 6mm can be attained.
|Density||23.0 °C||1.05 – 1.34 g/cm³|
|Tensile Strength||23.0 °C||20 – 60 MPa(at 350-800% strain)|
|Elastic modulus||23.0 °C||0.03 – 0.7 GPa|
|Elongation||23.0 °C||350 – 800 %|
|Specific heat capacity||23.0 °C||1500 – 1700 J/(kg·K)|
|Thermal conductivity||23.0 °C||0.14 – 0.5 W/(m·K)|
|Flammability||UL 94 HB||NA|
|Melting point||NA||120 – 220 °C|
|Max. service temprature – long||NA||80 – 90 °C|
|Max. servie temprature – short||NA||120 – 135 °C|
|Coefficient of thermal expansion||23.0 °C||1.1E-4 – 1.7E-4 1/K|
|Electrical resistivity||23.0 °C||1.00E+9 – 1.00E+12 Ω·m|
|Dielectric constant||23.0 °C||4 – 7 [-]|
|Application Areas||–||Cable sheathing, winter sports equipment, ear tags, mobile cases, etc.|
|Processing Methods||–||Injection molding, blow molding, extrusion|
Other Key Advantages:
- Across all the ranges of hardness, elasticity is always maintained. Various additives can improve heat resistance, dimensional stability, fungus resistance, reduce friction, and weatherability.
- Additives like UV absorbers, anti-oxidants, and anime stabilizers are used to protect polyurethanes from UV-light oxidation. Thus TPU plastic becomes compatible with applications demanding light or thermal stability.
- Aromatic TPU’s are another useful variation that is strong enough to withstand microbes and chemicals. A huge drawback is wearing attractiveness caused by prolonged exposure to heat and UV light. However, the degradation doesn’t leave any long-lasting impact but can cause discoloration and (in the worst case) loss of physical properties.
- On the other hand, allopathic TPU filament is naturally light stable and can easily withstand discoloration of any other damage from UV exposure. That makes them suitable as laminates overlapping on glass and glaze.
Limitations of TPU –
- Drying time is necessary before processing.
- A bit more expensive compared to other alternatives.
- The confined temperature range for the processing doesn’t help in making the process any faster.
- Some grades have a relatively short life cycle, which further can add costs.
- Requires special manufacturing conditions across all the major methods.
Thermoplastic Polyurethane Processing Methods –
TPU is a melt-processable material compatible with traditional processing methods like Injection molding, extrusion, compression, and blow molding. TPU can be easily fabricated into many shapes and sizes to create a variety of products.
TPU filaments are also often combined with organic solvents to form laminated textiles and functional additives.
For the smoothness of the process, drying is compulsory. Removing the moisture before processing is extremely crucial, or it will lead to loss of physical properties and brittleness.
Types of TPU Films –
There are three main types of TPU film available in the market – Polyester, Polyether, and Polycaprolactone.
|Constructed by ester subunits joining with each other by a method called ring-opening polymerization||Made by ether subunits combining in a process called ring-opening polymerization||Similarly, Produced by caprolactone subunits linking with each other by a process called ring-opening polymerization.|
|Compatible with PVC and other polar plastics||Slightly lower in terms of gravity than serval grade of polyester & polycarbonate||Exhibits inherent toughness and resistance to polyester-based TPUs|
|Fabulous abrasion resistance||Fantastic hydrolysis resistance||largely unaffected by oils and chemicals|
|Resisnt to oils and solvensts||Low-temperature flexibility||Low resistivity to high temperature and hydrolysis|
|Excellent balance physical properties||Can easily microbial attack||A high degree of crystallinity|
Applications of TPU Filaments-
TPU’s easy processability and versatility in its nature make it ideal for serval applications. Let’s discuss the main applications.
- Mobile Cases
- Textile Coatings
- TPU sheets
- Seals and Gaskets
- Sports and Leisure
- Tubes and Hoses
- Belts & Profiles Industry
#1 TPU Cases:
Perhaps the most popular TPU made product within the masses are the phone cases. Cases made from thermoplastic polyurethane are flexible, stylish, and, most important long-lasting(if you don’t want to keep spending money on buying new cases).
The only drawback is that the cases will be more susceptible to everyday wear and tear. However, the case will still provide good protection to your phone.
TPU boasts fantastic scratch and ageing properties, making it a wonderful choice for the highly sophisticated automotive industry. It’s a cheaper solution for manufacturers, thanks to its fast molding cycles.
Ageing and scratch resistance properties and inexpensive nature make TPU material applicable in gear knobs and console parts.
#3 Textile Coatings:
For textile applications, sintering, calendering, or T-die lamination processes should be utilized. TPU plastic’s terrific mechanical properties, chemical resistance, and weldability make it suitable for coating applications like inflatable items, converter belts, military equipment, etc.
#4 TPU Sheets:
TPU sheets provide unmatchable performance and quality for certain products. Among the most common application for TPU fils are textile coatings, inflatables, garments, adhesives, and barrier films.
T-die, calendering, and blown-extrusion film process is advisable for laminated films and sheets.
#5 Seals & Gaskets:
Seals and gaskets help in preventing leaking of some sort. Particular kinds of TPU filaments and additives have been developed in recent times to meet the rapidly growing demand for thermoplastic with adequate oil resistance and meager compression set.
Industrial high-pressure hydraulic seals are prime examples of such modification as it significantly improves its flow properties and lowers the compression ratios.
#6 Sports and Leisure:
Various sports and leisure items like jackets, shoes, etc., are made from TPU to take advantage of its supreme flexibility, clarity, good paintability, and environmental resistance.
#7 Tubes & Hoses:
Hoses and tubes are essential for the smooth handling of objects. The tremendous durability for working properly. That’s where TPU comes with durability and flexibility not easily found in other thermoplastics, not just that mechanical, chemical, and kink resistance makes it irreplaceable.
Prime applications include hydraulic wire bond hoses and pneumatic tubing.
#8 Belts & Profile:
TPU materials are well-known in the belts and profile industry for producing premium quality products. For example – converter belts, timing belts, etc.
TPU’s Creep resistance and long-discussed mechanical strength are to be thanked here.
The Future of Thermoplastic Polyurethane –
According to research conducted by marketsandmarkets, TPU will register a CAGR of 7.1% till 2024 to gross sales worth USD 3.5 Billion. The largest industry in terms of TPU consumption is footwear, and according to us, it will remain at the top for quite some time.
Other segments like automotive, medical, electronics, and industrial machinery are also growing rapidly for TPU.
Asia-Pacific remained the largest consumer of TPU plastic in 2020. It will remain the leader, growing its market share till 2024, followed by Europe, North America, Middle East & Africa, and South America.
TPU Market Share by region
Source – marketandmarket analysis
Out of all the TPU films, polycaprolactone is the most used and also the fastest growing in the market.
Obviously, things can be hindered due to the ongoing Covid-19 pandemic. Still, looking at the world tussle to win over history’s most ruthless pandemic, the vaccine’s rollout can make things bright and sunny once again for the world’s economy and manufacturing industry.
1. Is TPU material BPA free?
Ans. TPU does not contain Bisphenol-F (BPF), Bisphenol-S (BPS) or Bisphenol-A (BPA) or any other similar compounds (unlike polycarbonate or other epoxies) as it doesn’t require any of these to process.
2. Is TPU better than PVC?
Ans. Both materials have their pros and cons, but TPU tends to be tougher than PVC. Polyvinyl chloride has low shear strength. TPU is aslo sturdier because it has a high abrasion resistance that will withstand scratching and scuffing. One more point in TPU’s favour is that it is more environmentally friendly.
3. Why do TPU cases turn yellow?
Ans. A TPU case will turn yellow when exposed to sunlight, heat or certain chemicals. The change in colour is caused by natural degradation and is irreversible. The yellowish color won’t vanish with cleaning or bleaching. Although the yellowing is very normal, and it doesn’t affect the durability of the case.
4. Does TPU need cooling while 3D printing?
Ans. Usually, TPU doesn’t need a cooling fan, but a lot depends on the settings you’re using. For example, 3D printing with TPU without a cooling fan is normal, but it is recommended to use a cooling fan at around 40% if you’re printing at her temperature and high speeds. Using a cooling fan is also important when you have bridges.
5. How fast can you 3D print with TPU?
Ans. Print speed of flexible TPU filament should be in the range of 30 to 50 mm/sec. The optimum setting for the layer thickness is 0.1mm. Extrusion temperature is n the range of 200 to 220˚C with a heated bed platform set around 80 to 100˚C.
6. What is the difference between TPU and PLA?
Ans. TPU and PLA have some subtle differences. PLA is more environmentally friendly and is compostable. It is easier to print, and it can prove to e an ideal material for beginners. TPU is good for molding flexible parts that need to be able to return to their originals State.
The Takeaway –
Thus, were my thoughts on TPU material. I have tried my best to keep the post brief and informative. TPU filament is a blend of plastic and rubber, boasting properties that can be profitable for manufacturers and consumers.
Kindly share your thoughts and reviews in the comment section.
Have a Fantastic Day 🙂