TPU and BIO TPU Materials Investigation

Thermoplastic Polyurethane (TPU) and its bio-based counterpart, BIO-TPU, are materials used extensively in manufacturing and production, particularly in the fashion industry.
Man standing in a TPU made raincoat and outdoor clothing with snow ice balls in the background

This article delves into the differences between these materials, their composition, environmental impact, cost considerations, and how they are used, ultimately exploring the sustainability debate surrounding them.

TPU: What Is It and How Is It Made?

TPU is a versatile elastomer that bridges the gap between rubber and plastic. It is primarily made from petrochemicals, combining a base polymer with a diisocyanate and a chain extender. This material is prized for its durability, flexibility, and resistance to abrasion, oil, and grease. Its applications span from footwear soles to phone cases, outdoor gear, and performance textiles.

TPU is recyclable and, under certain conditions, biodegradable, but its manufacturing process is energy-intensive and relies heavily on fossil fuels. This results in a significant carbon footprint, contributing to its environmental drawbacks despite its technical recyclability.

BIO-TPU: The Sustainable Alternative

BIO-TPU, as the name suggests, is a bio-based version of TPU. It is derived from renewable resources like plant-based oils (e.g., castor oil) instead of petroleum. The chemical process remains similar, but the shift in raw material reduces dependence on non-renewable resources. BIO-TPU retains the advantageous properties of traditional TPU, such as elasticity, durability, and adaptability, but with a reduced environmental impact.

BIO-TPU is becoming a preferred choice in industries looking to align with sustainable practices, particularly in fashion and footwear, where materials contribute significantly to a product’s overall environmental footprint. But there is still a long way to go.

Comparing Environmental Impacts

While TPU is biodegradable and recyclable, its petrochemical origin and energy-intensive production processes pose challenges. Recycling TPU requires specialized infrastructure, and biodegradable claims often depend on specific environmental conditions, such as industrial composting, which are not universally available.

BIO-TPU, on the other hand, has a lower carbon footprint due to its reliance on renewable resources. However, it is not without challenges. Large-scale production of bio-based materials can put pressure on agricultural systems, and end-of-life management, such as composting or recycling, needs to be considered for true circularity.

Cost Differences and Market Adoption

The production cost of BIO-TPU remains higher than that of traditional TPU, primarily due to the price of bio-based feedstocks and the relatively lower scale of production. This cost disparity is a barrier to widespread adoption, particularly in cost-sensitive industries. However, with growing consumer demand for sustainable materials and advancements in production technology, BIO-TPU could become more affordable in the future.

Applications in Manufacturing and Fashion

TPU is widely used in the fashion industry for making flexible and durable components like shoe soles, waterproof garments, and accessories. BIO-TPU is beginning to replace TPU in some of these applications, particularly in high-end and eco-conscious brands looking to appeal to environmentally aware consumers.

Manufacturers are also exploring how BIO-TPU can be integrated into circular manufacturing systems, where materials can be recovered and reused at the end of their life cycle. This aligns with fashion’s push toward circularity and reduced waste.

The Case for BIO-TPU

While TPU has served industries well with its versatility and durability, its petrochemical roots and problematic manufacturing process make it a less sustainable choice. BIO-TPU offers a greener alternative by reducing reliance on fossil fuels and lowering carbon emissions. However, for BIO-TPU to truly compete, the industry must address its higher costs and invest in scalable solutions.

As consumers and industries continue to prioritise sustainability, the shift towards BIO-TPU seems inevitable. To accelerate this transition, policymakers, manufacturers, and brands must work together to create incentives for bio-based material adoption, invest in research and development, and educate consumers on the importance of choosing sustainable alternatives.

By replacing TPU with BIO-TPU where feasible, industries, including fashion, can take a step closer to reducing their environmental impact while maintaining the performance standards demanded by modern products.

Pricing

Thermoplastic Polyurethane (TPU) and its bio-based counterpart, BIO-TPU, differ notably in cost due to their raw material sources and production scales. Traditional TPU, derived from petrochemicals, typically costs between $2.00 and $4.00 per kilogram. In contrast, BIO-TPU, produced from renewable resources like vegetable oils, is priced higher, ranging from $10 to $15 per kilogram.

This price disparity stems from several factors:

Raw Material Costs
Bio-based feedstocks are generally more expensive than petroleum-based inputs.

Production Scale
The manufacturing infrastructure for BIO-TPU is less developed, leading to higher per-unit costs.

Technological Development
BIO-TPU production processes are still evolving, which can result in higher operational expenses.

As demand for sustainable materials grows and production technologies advance, the cost of BIO-TPU is expected to decrease, potentially narrowing the gap with traditional TPU.

Outdoor wear tents using TPU

Alternatives to TPU

Alternatives to TPU for sustainable manufacturing go beyond BIO-TPU and focus on renewable, biodegradable, and environmentally friendly materials. These include bioplastics, natural rubbers, and innovative composites designed to reduce ecological impact. Below are some noteworthy alternatives:

1. Polylactic Acid (PLA)

Source: Derived from renewable resources such as corn starch or sugarcane.
Sustainability: Fully biodegradable under industrial composting conditions.
Applications: Used in packaging, 3D printing, and some textile coatings.
Challenges: Less flexible and durable than TPU, limiting its use in high-performance applications.

2. Polyhydroxyalkanoates (PHAs)

Source: Produced by bacterial fermentation of sugars and oils.
Sustainability: Fully biodegradable and bio-based.
Applications: Suitable for packaging, medical implants, and some textiles.
Challenges: Higher cost and limited scalability compared to petroleum-based materials.

3. Natural Rubber

Source: Harvested from the latex of rubber trees.
Sustainability: Renewable and biodegradable if sourced sustainably.
Applications: Used in footwear, elastic textiles, and industrial applications.
Challenges: Requires careful management to avoid deforestation and ensure ethical labor practices.

4. Silicone

Source: Made from silica (sand) and oxygen, with some synthetic inputs.
Sustainability: Non-toxic and long-lasting, reducing waste; some silicones are recyclable.
Applications: Used in fashion (e.g., adhesives, textiles), medical devices, and cookware.
Challenges: Not biodegradable and relies on energy-intensive production.

5. Mycelium-Based Materials

Source: Derived from fungal roots grown on agricultural waste.
Sustainability: 100% biodegradable, renewable, and produced with minimal energy.
Applications: Used in footwear, fashion accessories, and packaging.
Challenges: Limited scalability and specific material properties compared to TPU.

6. Castor Oil-Based Polyurethanes

Source: Derived from castor oil, a renewable resource.
Sustainability: Partially bio-based with lower environmental impact than traditional TPU.
Applications: Used in fashion, furniture, and performance sports equipment.
Challenges: Often combined with non-renewable inputs, reducing overall sustainability.

7. Recycled TPU

Source: Made by reprocessing post-consumer or industrial TPU waste.
Sustainability: Reduces reliance on virgin materials and diverts waste from landfills.
Applications: Can replace virgin TPU in many products, including footwear and textiles.
Challenges: Limited by contamination issues and the availability of recycling infrastructure.

8. Cork-Based Composites

Source: Harvested from cork oak bark, a renewable resource.
Sustainability: 100% biodegradable, renewable, and non-toxic.
Applications: Used in footwear, accessories, and interior design.
Challenges: Less flexible and durable than TPU, limiting its use in some applications.

9. Starch-Based Thermoplastics

Source: Derived from potato, corn, or tapioca starch.
Sustainability: Renewable and biodegradable under specific conditions.
Applications: Used in packaging, disposable items, and low-performance products.
Challenges: Limited mechanical strength compared to TPU.

10. Gelatin-Based Bioplastics

Source: Made from animal by-products or plant-based gelatin.
Sustainability: Biodegradable and can be composted.
Applications: Used in food packaging and experimental textiles.
Challenges: Sensitivity to moisture and temperature limits broader use.

Future Innovations

Emerging materials such as seaweed-based bioplastics, wood fibre and nanocellulose composites are also being explored as sustainable alternatives. These materials promise to deliver TPU-like properties with greater environmental benefits, but their commercial readiness varies.

Getting the Low down

The choice of alternative depends on the specific application, desired properties, and environmental goals. While BIO-TPU offers a direct replacement with minimal changes to manufacturing processes, other alternatives like PLA, PHA, and mycelium-based materials provide innovative options that may require rethinking design and production approaches for better sustainability.

Several companies specialize in recycling Thermoplastic Polyurethane (TPU) and supplying recycled TPU materials. Notable examples include:

Novoloop
This company transforms post-industrial TPU trim scrap into high-quality recycled TPU with over 96% recycled content, suitable for various applications.

Gianeco
Gianeco offers recycled TPU in both pellet and regrind forms, sourced from production waste and post-consumer items, promoting sustainability in the plastics industry.

Covestro
Covestro is developing more circular TPU solutions by incorporating partially bio-based and recycled materials, aiming to reduce the carbon footprint of TPU products.

CHC Waste Management
Specialising in recycling polyurethane foams, CHC handles high volumes of polyurethane foam from various industries, ensuring non-contaminated material is baled and sent for recycling within the UK.

Permali
Manufacturer of Tuftane® TPU films, Permali offers a range of TPU grades and works closely with customers to provide materials that meet specific processing and performance requirements.

These companies contribute to the circular economy by recycling TPU materials and supplying them for various industrial applications.

Several companies across various industries are integrating recycled Thermoplastic Polyurethane (TPU) into their products, underscoring a commitment to sustainability. Notable examples include:

1. Fairphone

Application: The protective case for Fairphone 3 and Fairphone 4 smartphones.
Details: Fairphone collaborates with Covestro to utilize fully and partially recycled TPU in their smartphone cases, supporting a circular economy in electronics.

2. Adidas

Application: Footwear components.
Details: Adidas incorporates recycled TPU in the soles of certain shoe models, aligning with their sustainability initiatives.

3. Nike

Application: Footwear and apparel.
Details: Nike uses recycled TPU in various products to enhance sustainability and reduce environmental impact.

4. Recreus

Application: 3D printing materials.
Details: Recreus offers Reciflex, a 100% recycled TPU filament made from footwear industry waste, promoting sustainable 3D printing practices.

5. Salvatore Ferragamo

Application: Footwear.
Details: The luxury brand utilizes recycled pre-consumer TPU for the soles of its shoes, integrating sustainable materials into their designs.

6. Patagonia

Application: Waterproof garments.
Details: Patagonia produces waterproof jackets and sportswear using recycled TPU for the waterproof and breathable membranes.

7. The North Face

Application: Outdoor apparel.
Details: The North Face incorporates recycled TPU in the waterproof and breathable linings of some jackets and pants.

8. Hoka

Application: Footwear.
Details: Hoka uses recycled TPU in the soles of certain shoe models, contributing to their sustainability efforts.

9. Salomon

Application: Outdoor gear.
Details: Salomon utilizes recycled TPU in the waterproof and breathable membranes of some jackets and pants.

10. Calvin Klein

Application: Footwear and fitness apparel.
Details: Calvin Klein offers sneakers with outer soles made from 100% recycled TPU and uses recycled TPU for the waterproof and breathable linings of some fitness jackets and pants.

These companies are just a few examples of how fashion brands are integrating recycled TPU into their products, The best case scenario though, is switching to TPU BIO in the long run.

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