BASF Elastollan: A Comprehensive Overview of Thermoplastic Polyurethane Elastomers

Introduction

Elastollan® is a globally recognized brand of thermoplastic polyurethane elastomer (TPU) manufactured by BASF. These materials are characterized by their exceptional abrasion resistance, high elasticity, excellent low-temperature flexibility, and resistance to oils, greases, and a variety of chemicals. Elastollan® TPUs bridge the gap between rubbers and plastics, offering a unique combination of properties that make them suitable for a wide array of applications across diverse industries. This article provides a comprehensive overview of Elastollan® TPUs, covering their chemical structure, properties, processing techniques, applications, and grades, while adhering to a rigorous and standardized approach.

1. Chemical Structure and Composition

Thermoplastic polyurethanes, including Elastollan®, are block copolymers consisting of alternating soft and hard segments. This unique structure imparts the characteristic elastomeric properties to the material.

• Hard Segments: These segments are typically formed by the reaction of a diisocyanate (e.g., MDI – Methylene Diphenyl Diisocyanate, or HDI – Hexamethylene Diisocyanate) with a chain extender, which is usually a short-chain diol (e.g., 1,4-Butanediol or Ethylene Glycol). The hard segments are responsible for the material’s strength, stiffness, and heat resistance. They tend to aggregate and form crystalline or semi-crystalline domains that act as physical crosslinks.

• Soft Segments: These segments are derived from a long-chain diol or polyol (e.g., Polyether Polyol or Polyester Polyol). The soft segments contribute to the material’s flexibility, elasticity, and low-temperature performance. Their amorphous nature allows for chain mobility and deformation under stress.

The ratio of hard to soft segments, along with the specific chemical nature of each component, significantly influences the final properties of the Elastollan® TPU. By carefully controlling these parameters, BASF offers a wide range of Elastollan® grades tailored to specific application requirements.

2. Key Properties and Characteristics

Elastollan® TPUs offer a compelling combination of properties, making them a versatile material for numerous applications. Key properties include:

• High Abrasion and Wear Resistance: One of the most distinguishing features of Elastollan® TPUs is their exceptional resistance to abrasion and wear. This property makes them ideal for applications involving friction and contact with abrasive surfaces.

• High Tensile Strength and Elongation: Elastollan® TPUs exhibit high tensile strength and elongation at break, allowing them to withstand significant stress and deformation without failure.

• Excellent Elasticity and Resilience: They demonstrate excellent elasticity, meaning they can be stretched and returned to their original shape without permanent deformation. This resilience is crucial in applications requiring repeated flexing or impact resistance.

• Good Chemical Resistance: Elastollan® TPUs possess good resistance to a wide range of chemicals, including oils, greases, solvents, and fuels. This resistance is crucial in demanding industrial environments.

• Low-Temperature Flexibility: Certain grades of Elastollan® TPUs maintain their flexibility and impact resistance at low temperatures, making them suitable for outdoor applications and cold environments.

• Hydrolysis Resistance: Some Elastollan® grades are formulated to resist degradation in humid or wet environments, making them suitable for applications involving exposure to water or moisture. This is especially important for polyether-based TPUs.

• UV Resistance: Additives can be incorporated into Elastollan® TPUs to enhance their resistance to ultraviolet (UV) radiation, preventing discoloration and degradation of mechanical properties when exposed to sunlight.

• Processability: Elastollan® TPUs can be processed using various techniques, including injection molding, extrusion, and blow molding, allowing for the production of complex shapes and designs.

The following table summarizes typical property ranges for Elastollan® TPUs. Specific values will vary depending on the grade.

Property	Unit	Typical Range	Test Method
Hardness	Shore A/D	60A – 85D	ASTM D2240
Tensile Strength	MPa	20 – 60	ASTM D412
Elongation at Break	%	200 – 700	ASTM D412
Tear Strength	kN/m	20 – 100	ASTM D624
Abrasion Resistance (Taber)	mg loss/1000 cycles	5 – 50	ASTM D4060
Specific Gravity	g/cm³	1.05 – 1.30	ASTM D792
Service Temperature Range	°C	-40 to +120	Varies by Grade

3. Elastollan® Product Grades and Applications

BASF offers a wide variety of Elastollan® grades, each tailored to specific applications and performance requirements. These grades are broadly categorized based on their chemical composition, hardness, and specific properties.

• Polyether-Based Elastollan®: These grades offer excellent hydrolysis resistance and low-temperature flexibility, making them suitable for applications involving exposure to moisture or cold environments. Examples include:

  • Elastollan® C Series: General-purpose polyether TPUs with good overall performance. Commonly used in automotive applications, hoses, and seals.
  • Elastollan® S Series: High-performance polyether TPUs with enhanced chemical resistance and low-temperature flexibility. Often used in demanding industrial applications.

• Polyester-Based Elastollan®: These grades exhibit superior abrasion resistance, oil resistance, and tensile strength compared to polyether-based TPUs. They are well-suited for applications requiring high durability and resistance to oils and fuels. Examples include:

  • Elastollan® B Series: General-purpose polyester TPUs with excellent abrasion resistance. Widely used in footwear, automotive parts, and industrial components.
  • Elastollan® 11 Series: High-performance polyester TPUs with enhanced tensile strength and oil resistance. Often used in hydraulic seals, drive belts, and conveyor belts.

• Caprolactone-Based Elastollan®: These grades offer a balance of properties, including good abrasion resistance, hydrolysis resistance, and low-temperature flexibility. They are often used in medical devices and other applications requiring biocompatibility.

• Specialty Elastollan® Grades: BASF also offers a range of specialty Elastollan® grades with unique properties, such as flame retardancy, static dissipative properties, or enhanced UV resistance.

The following table provides a simplified overview of some common Elastollan® grades and their typical applications.

Elastollan® Grade	Polymer Type	Hardness (Shore A/D)	Key Properties	Typical Applications
Elastollan® C70A	Polyether	70A	Good hydrolysis resistance, low-temperature flexibility	Hoses, seals, cable jacketing, automotive bellows
Elastollan® C85A	Polyether	85A	Good hydrolysis resistance, low-temperature flexibility, higher strength	Automotive components, industrial tubing, conveyor belts
Elastollan® B60A	Polyester	60A	Excellent abrasion resistance, high tensile strength	Footwear, rollers, caster wheels, protective films
Elastollan® B80A	Polyester	80A	Excellent abrasion resistance, high tensile strength	Footwear, rollers, caster wheels, protective films, drive belts
Elastollan® 1185A	Polyester	85A	Excellent oil resistance, high tensile strength, abrasion resistance	Hydraulic seals, gaskets, automotive components, high-performance industrial parts
Elastollan® 1190A	Polyester	90A	Excellent oil resistance, high tensile strength, abrasion resistance	Hydraulic seals, gaskets, automotive components, high-performance industrial parts, gears
Elastollan® 1170D	Polyester	70D	High abrasion resistance, high tensile strength, rigid	Automotive components, industrial parts requiring high stiffness

Detailed Application Areas:

• Automotive Industry: Elastollan® TPUs are extensively used in automotive applications due to their excellent abrasion resistance, chemical resistance, and durability. Common applications include:

  • Seals and Gaskets: Elastollan® provides reliable sealing performance in various automotive systems, resisting degradation from fuels, oils, and coolants.
  • Hoses and Tubing: Elastollan® offers excellent flexibility and resistance to chemicals, making it ideal for fuel lines, coolant hoses, and airbrake tubing.
  • Cable Jacketing: Elastollan® protects electrical cables from abrasion, chemicals, and extreme temperatures.
  • Suspension Components: Elastollan® provides excellent damping and vibration isolation in suspension components.
  • Interior Parts: Elastollan® is used in interior trim, door panels, and other components due to its abrasion resistance and aesthetic appeal.

• Footwear Industry: Elastollan® TPUs are widely used in the footwear industry due to their excellent abrasion resistance, flexibility, and comfort. Key applications include:

  • Outsoles: Elastollan® provides excellent traction and durability in outsoles, resisting wear and tear from rough surfaces.
  • Midsoles: Elastollan® offers cushioning and support in midsoles, enhancing comfort and performance.
  • Uppers: Elastollan® provides flexibility and durability in uppers, conforming to the foot and resisting abrasion.

• Industrial Applications: Elastollan® TPUs are utilized in a wide range of industrial applications due to their excellent abrasion resistance, chemical resistance, and mechanical properties. Common applications include:

  • Hoses and Tubing: Elastollan® provides reliable performance in industrial hoses and tubing, resisting degradation from chemicals and abrasion.
  • Seals and Gaskets: Elastollan® offers excellent sealing performance in industrial equipment, preventing leaks and maintaining system integrity.
  • Drive Belts: Elastollan® provides high tensile strength and abrasion resistance in drive belts, ensuring reliable power transmission.
  • Conveyor Belts: Elastollan® offers excellent durability and resistance to abrasion in conveyor belts, handling a variety of materials.
  • Rollers and Wheels: Elastollan® provides excellent abrasion resistance and load-bearing capacity in rollers and wheels, ensuring smooth and reliable operation.

• Medical Applications: Certain grades of Elastollan® TPUs are suitable for medical applications due to their biocompatibility, flexibility, and resistance to sterilization. Common applications include:

  • Catheters: Elastollan® provides flexibility and biocompatibility in catheters, allowing for easy insertion and minimizing patient discomfort.
  • Tubing: Elastollan® offers excellent chemical resistance and flexibility in medical tubing, ensuring reliable fluid transfer.
  • Wound Dressings: Elastollan® provides a protective barrier against infection in wound dressings, promoting healing.

• Wire and Cable Industry: Elastollan® TPUs are used as jacketing materials for wires and cables due to their excellent abrasion resistance, chemical resistance, and electrical insulation properties. They offer protection against environmental factors and mechanical stress.

4. Processing Techniques

Elastollan® TPUs can be processed using various techniques, including:

• Injection Molding: This is the most common processing method for Elastollan® TPUs. The material is melted and injected into a mold cavity, where it cools and solidifies to form the desired shape. Injection molding is suitable for producing high-volume parts with complex geometries.

• Extrusion: In this process, the Elastollan® TPU is melted and forced through a die to create continuous profiles, such as tubes, hoses, sheets, and films. Extrusion is ideal for producing long, uniform shapes.

• Blow Molding: This technique is used to produce hollow parts, such as bottles and containers. The Elastollan® TPU is extruded into a parison (a hollow tube), which is then inflated inside a mold cavity to form the desired shape.

• Thermoforming: Sheets of Elastollan® TPU can be heated and formed into three-dimensional shapes using vacuum, pressure, or mechanical force. Thermoforming is suitable for producing large, thin-walled parts.

• Overmolding: Elastollan® TPUs can be overmolded onto other materials, such as plastics or metals, to create composite parts with enhanced properties. This technique is often used to create soft-touch grips or improve the aesthetics of a product.

Processing Considerations:

• Drying: Elastollan® TPUs are hygroscopic and absorb moisture from the air. It is essential to dry the material before processing to prevent hydrolysis and ensure good part quality. Typical drying conditions are 80-100°C for 2-4 hours.

• Temperature Control: Precise temperature control is crucial during processing to ensure proper melting and flow of the Elastollan® TPU. Recommended melt temperatures typically range from 180-230°C, depending on the grade.

• Mold Design: Proper mold design is essential for achieving good part quality and minimizing defects. Considerations include gate location, venting, and cooling.

• Screw Design: The screw design in injection molding and extrusion machines should be optimized for processing Elastollan® TPUs. A general-purpose screw with a moderate compression ratio is typically recommended.

5. Sustainability and Environmental Considerations

BASF is committed to sustainability and offers Elastollan® grades with enhanced environmental performance. These grades may incorporate recycled content, bio-based materials, or be designed for improved recyclability.

• Recycled Content: Some Elastollan® grades incorporate post-industrial or post-consumer recycled content, reducing reliance on virgin materials.

• Bio-Based Materials: BASF is exploring the use of bio-based polyols in Elastollan® TPUs, reducing dependence on fossil fuels.

• Recyclability: BASF is actively working to improve the recyclability of Elastollan® TPUs, promoting circular economy principles.

6. Future Trends and Developments

The field of thermoplastic polyurethanes is continuously evolving, with ongoing research and development focused on improving material properties, expanding application areas, and enhancing sustainability. Key trends and developments include:

• Development of High-Performance TPUs: Research is focused on developing TPUs with enhanced properties, such as higher temperature resistance, improved chemical resistance, and increased durability.

• Nanocomposite TPUs: Incorporating nanoparticles into TPU matrices can significantly improve mechanical properties, thermal stability, and barrier properties.

• 3D Printing of TPUs: TPUs are increasingly being used in 3D printing applications, enabling the creation of complex geometries and customized parts.

• Smart TPUs: Development of TPUs with sensing capabilities, such as pressure sensing or temperature sensing, is opening up new possibilities in wearable devices and other applications.

• Bio-Based and Biodegradable TPUs: Research is focused on developing TPUs based on renewable resources and biodegradable materials to reduce environmental impact.

7. Conclusion

Elastollan® TPUs offer a versatile combination of properties that make them suitable for a wide range of applications across diverse industries. Their excellent abrasion resistance, high elasticity, chemical resistance, and processability make them a compelling choice for demanding applications. As technology continues to advance, Elastollan® TPUs are poised to play an increasingly important role in shaping the future of materials science and engineering. BASF’s commitment to innovation and sustainability ensures that Elastollan® will continue to be a leading brand in the TPU market.

Literature Sources:

• Oertel, G. (Ed.). (1993). Polyurethane Handbook. Hanser Gardner Publications.
• Hepburn, C. (1991). Polyurethane Elastomers. Elsevier Science Publishers.
• Saunders, J. H., & Frisch, K. C. (1962). Polyurethanes: Chemistry and Technology. Interscience Publishers.
• Ashworth, V., & Hepworth, D. (2016). Thermoplastic Polyurethanes. iSmithers Rapra Publishing.
• Rosthauser, J. W., & Nachtkamp, K. (1987). Water-Borne Polyurethanes. Advances in Urethane Science and Technology, 10, 121-162.
• Randall, D., & Lee, S. (2002). The Polyurethanes Book. John Wiley & Sons.
• Woods, G. (1990). The ICI Polyurethanes Book. John Wiley & Sons.
• Szycher, M. (1999). Szycher’s Handbook of Polyurethanes. CRC Press.
• Prociak, A., Ryszkowska, J., & Uramowski, G. (2017). Polyurethane Thermoplastic Elastomers: Synthesis, Morphology, Properties and Applications. Elsevier.

This article provides a comprehensive overview of BASF Elastollan® TPUs, covering their chemical structure, properties, processing techniques, applications, and future trends. It aims to be informative and useful for engineers, designers, and anyone interested in learning more about this versatile material. Remember to always consult the specific product datasheet for detailed information on a particular Elastollan® grade.

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