The use of a single material eliminates the need for complex separation processes often required in the recycling of traditional synthetic turf products containing multiple materials. This not only reduces costs and simplifies the recycling process, but also ensures a higher quality of recycled material. The choice of Monomaterial such as polyethylene as the sole material is because of its durability, recyclability and low environmental impact compared to other polymers.

Monomaterial artificial turf reflects a larger trend within industries such as packaging, where monomaterials are increasingly preferred for similar reasons. This trend is also in line with global sustainability initiatives, such as the European Green Deal and the Sustainable Development Goals (SDGs), which emphasise the importance of efficient resource use and minimising waste.

Targeting a climate-neutral Europe by 2050, the European Green Deal is strongly committed to circularity and sustainability in all sectors, including the production of consumer goods such as artificial turf. By using monomaterials, which facilitates recycling and increases the quality of recycled materials, monomaterial artificial grass contributes directly to these goals.

Sustainable Development Goals (SDGs)

Specifically, monomaterial synthetic turf contributes to SDG 12: Responsible consumption and production, which calls for reducing waste production through prevention, reduction, recycling and reuse. Choosing a monomaterial fits perfectly within this objective, as it extends the product’s life cycle and minimises its impact on the environment.

Packaging industry

In the packaging industry, similar steps are being taken towards the use of monomaterials. This not only simplifies the recycling process, but also reduces the pollution associated with multi-material packaging. Organisations such as Ellen MacArthur Foundation offer extensive resources on how the packaging industry can move towards more circular practices.

Moving to mono-materials is an example of how industries can contribute to the circular economy. This choice reduces the complexity of the recycling process, which is essential for achieving the higher recycling targets set in the European Green Deal. Moreover, the use of monomaterials helps reduce the carbon footprint and use resources more efficiently, leading to more sustainable production and consumption.

• Definition and Composition
  • Monomaterials: Products made from monomaterials contain only one type of material or polymer for the entire product. This design promotes consistency through all components of the product.
  • Multi-materials: Many traditional products, including artificial grass, use a mix of different materials such as polyethylene, polypropylene and latex. This mix complicates recycling processes and affects the quality of the recycled material.
• Benefits of Monomaterials
  • Simplified Recycling: Monomaterials eliminate the need to separate materials during the recycling process, which increases efficiency and reduces costs. This leads to higher quality recycled material and makes the process more sustainable.
  • High-quality reuse options: The use of one material type ensures that recycled products are of higher quality and avoids the degradation of material properties that often occurs when recycling multi-materials (downcycling).
    Sustainability and CO2 reduction: Production processes for mono-materials are often more efficient and generate fewer CO2 emissions because they are simpler and less energy-intensive than processes required to process multiple materials.
  • Resource efficiency: Uniformity in production promotes efficient use of raw materials, which helps reduce demand for new materials and reduces the environmental impact of the product.
• Industrial Implementation and Regulation
  • Sustainability standards: Globally, regulatory bodies and industry standards recognise the benefits of mono-materials in improving product recyclability. This encourages companies to adopt innovative designs that contribute to a circular economy.
  • Market adaptation: Products designed with monomaterials are becoming increasingly popular as an eco-friendly alternative, as they help meet both consumer demand and regulatory requirements for sustainable production and waste management.

• Different Melting Points
  • Definition of Melting Point: The melting point of a material is the temperature at which it changes from a solid to a liquid state. Different polymers have different melting points, meaning they melt at different temperatures.
  • Example: Polyethylene (PE) and polypropylene (PP) are two commonly used polymers in artificial turf and both have different melting points. PE has a melting point of around 120 °C, while PP only melts around 165 °C because it is a harder material. This difference can cause significant problems during the recycling process.
• Complications due to melting differences
  • Separation challenges: In recycling processes that use heat to melt materials for reuse, the different materials must be carefully separated to prevent materials with lower melting points from burning or degrading before materials with higher melting points melt. This requires complex and costly separation processes.
  • Quality reduction: If materials with different melting points are mixed in a recycling process, this can lead to uneven melting, resulting in a lower-quality recycled product. The end product may contain weaknesses or inconsistencies, reducing its usability and durability.
  • Process efficiency: The need to separate materials prior to the recycling process or to use special technologies to deal with the variation in melting points increases the time and cost of recycling. This makes the process less efficient and less economically viable on a large scale.
• Solutions and Alternatives
  • Improved Separation Technologies: Technological advances in separation technologies, such as advanced sorting technologies and improved mechanical separation processes, can help separate materials more efficiently before recycling.
  • Design for Recyclability: Producers can design products with recyclability in mind, such as the use of mono-materials, which reduces the need for separation and simplifies the entire recycling process.

• Problems with Processing
  • Incomplete Melting: When materials with different melting points are processed together, those with a lower melting point may melt or even burn before materials with a higher melting point begin to melt. This leads to inconsistencies in the melting process, with some materials overheating while others are still solid.
  • Damage from Heat: Materials with a lower melting point may degrade or chemically break down when exposed to the higher temperatures required to melt the harder polymers. This can result in the formation of harmful by-products and a loss of mechanical properties.
• Impact on Recyclate Quality
  • Reduced Quality of Recycled Material: If materials with different melting points are not properly separated before melting, the end product may exhibit defects such as weak points, uneven texture, and reduced structural integrity. This limits the applicability of the recycled material for high-value applications.
  • Limitations in Applications: Recyclates consisting of a mix of unevenly melted materials are often only suitable for lower-grade applications, which reduces the value of the recyclate and lowers the economic viability of recycling.
• Complexity and Cost
  • Requirement for Advanced Separation: To recycle effectively, the different materials must first be carefully separated according to their melting point, which requires advanced and expensive technologies. This increases the cost and complexity of the recycling process.
  • Energy consumption: The need to melt some components at higher temperatures requires more energy, which increases the energy consumption of the recycling process and reduces its environmental benefits.
• Environmental impacts
  • Increase in CO2 emissions: Higher energy requirements for processing materials with different melting points lead to higher CO2 emissions during the recycling process.
  • Waste generation: If materials with different melting points cannot be separated efficiently, this may result in a higher amount of waste because some mixed materials are not reusable.

A blend of polyethylene (PE) and polypropylene (PP) is not considered a monomaterial composition. Although PE and PP both belong to the family of polyolefins and are chemically similar, they are separate types of polymers with different physical properties, including melting points and chemical resistance.

Problems with a Mix of PE and PP

• Different Melting Points: PE and PP have different melting points. PE usually melts around 120°C, while PP melts around 160°C. This discrepancy can cause problems in recycling, as it is difficult to achieve a uniform melt without one of the materials degrading.
• Separation requirements: For effective recycling, PE and PP need to be separated, which requires additional steps in the recycling process. This makes the process more complex and expensive.
• Quality of Recycled Material: If PE and PP are recycled together without adequate separation, the end product may be of lower quality. The mixing of different polymers can lead to weaknesses in recycled products and limit their applicability (downcycling).

A monomaterial consists of only one type of polymer or material throughout the product. This means that all components of the product (such as the fibres and backing of artificial turf) consist of the same material. This facilitates the recycling process as the entire product can be processed in one process without the need for separation of PE, PP and even Latex or PU.

Using a mix of PE and PP, although potentially beneficial for certain product properties, poses a challenge for recycling and does not meet the criteria for a mono-material. Products designed with true mono-material have a significant advantage in terms of sustainability and circularity, as they can be recycled more efficiently and effectively. To promote a circular economy and reduce environmental impact, it is advisable to choose mono-materials whenever possible.

• Use of Monomaterials: By designing products with only one type of material, many of these problems can be avoided. This greatly simplifies the recycling process and increases the quality of the recycled material.
• Improved Separation Technologies: Investment in more advanced separation technologies can help separate materials more efficiently and cost-effectively based on their physical and chemical properties.

These factors highlight why a difference in melting points is a challenging aspect in the recycling process of multi-materials, and emphasize the importance of innovation and careful material selection in product design for sustainability goals.

Polyethylene (PE) is a widely used thermoplastic polymer, meaning it can be melted to a liquid state and then solidify again when cooled. It is known for its strength, durability and versatility, making it a popular choice for a wide range of applications.

• Quality of recycled material: PE can be recycled several times without significant loss of quality, provided the recycling process is carried out carefully. The type of PE (e.g. HDPE or LDPE), the purity of the separated materials, and the recycling technique all play a role in maintaining material quality after recycling.
• Reduction of properties: Although PE is relatively stable, repeated recycling can eventually lead to degradation of certain physical properties such as tensile strength and flexibility. Additions of virgin (new) material during the recycling process can help maintain material properties.
• Applications of recycled PE: Recycled PE is widely used in products where there are less stringent material requirements, such as plastic bags, containers, and non-food packaging. For applications where higher material requirements apply, such as in the medical sector or food packaging, virgin PE is often used.

Durability over Years of Use

• Resistance to environmental factors: PE is chemically resistant and waterproof, which contributes to its long life. However, it is sensitive to UV radiation, which can lead to discolouration and weakening of the material if not adequately stabilised for sunlight exposure.
• Lifespan: The lifespan of products made of PE can vary from a few years to several decades, depending on environmental factors and the quality of the material. For example, in construction applications, PE pipes can last more than 50 years underground without significant degradation.
• Degradation through use: Mechanical wear, constant exposure to high temperatures, and chemical exposure can all contribute to the degradation of PE over time. Under normal conditions of use, however, PE is a very stable material.

The choice of using recycled versus virgin PE often depends on the specific requirements of the product and the availability of high-quality recycled material. Innovations in recycling technologies and improvements in separation techniques are expected to further improve the quality and usability of recycled PE in the future.

Polypropylene (PP), like polyethylene (PE), is a commonly used polymer in the production of artificial turf. Using PP as a mono-material for artificial grass offers certain advantages, but it also has some limitations. Here are the main considerations:

Benefits of PP as a Monomaterial for Artificial Grass

• Recyclability: PP is fully recyclable, making it an attractive option for applications where sustainability is a priority. When artificial grass is made entirely of PP, including the fibres and backing, it greatly simplifies the recycling process because the material is homogeneous.
• Chemical resistance: PP is resistant to most chemical solvents, bases and acids, making it a durable material that resists well to different weather and soil conditions.
• Cost: PP is generally cheaper than some other polymers, including certain types of PE. This can reduce the cost of producing artificial turf, which is especially important for large-scale applications.

Disadvantages of PP as a monomaterial for Artificial Grass

• UV stability: Although PP resists many forms of abrasion well, it is less UV stable than PE unless it is adequately stabilised. UV radiation can cause discolouration and degradation of the material, which can shorten the life of the artificial grass.
• Mechanical properties: PP is stiffer and less flexible than PE. This can affect the resilience and comfort of the artificial grass. It feels stiffer and will be less suitable for landscape applications, where comfort is important. For sports applications, where flexibility and resilience are important properties, this can also be a disadvantage.
• Temperature sensitivity: PP has a higher melting point than PE but is also sensitive to cold temperatures where it can become brittle. This can be a problem in climates where extreme temperatures occur.

Conclusion

Whether PP is a good choice for mono-material artificial turf depends on the specific application and the required properties of the final product. For general use in landscaping and decorative applications, PP can be a cost-effective and durable choice, provided it is well stabilised against UV radiation. For sports applications or applications in climates with extreme temperatures, there may be better alternatives.

Designing artificial turf systems composed solely of PP can increase recyclability and contribute to sustainability goals, but it is important to balance environmental benefits with the functional requirements of the artificial turf.

Polyethylene terephthalate, better known as PET, is another widely used polymer that offers advantages for use in artificial turf, especially when considering implementing monomaterial systems. Using PET for artificial turf brings both benefits and certain challenges, depending on the application and the desired properties of the final product.

Benefits of PET as a Monomaterial for Artificial Grass

• Recyclability: PET is highly recyclable and is already widely recycled, mainly in the packaging industry (think plastic bottles). Artificial grass made entirely of PET would be easier to recycle after use, as it does not require complex separation of different materials.
• Durability: PET is resistant to water, many chemicals and weather conditions, including UV radiation. It has good dimensional stability and retains its shape and strength under different environmental conditions.
• Strength and Resilience: PET fibres are strong and resilient, making them suitable for applications where a higher degree of abrasion resistance is required, such as sports fields.

Disadvantages of PET as a monomaterial for Artificial Grass

• Cost and Processing: Producing PET fibres can be more expensive than other plastics such as PE or PP. PET also requires higher processing temperatures, which can increase production costs.
• Stiffness: While PET’s strength can be an advantage, its inherent stiffness can make it less comfortable compared to softer materials such as PE. This can be especially a disadvantage in applications such as playing fields or other recreational areas.
• Energy-intensive in Production: PET production is more energy-intensive compared to some other plastics. This may increase the carbon footprint of PET products, something that should be considered in the context of sustainability goals.

Conclusion

PET can be a good choice for artificial turf when high strength and excellent weather resistance are required. Its excellent recyclability also makes it an attractive mono-material in terms of environmental friendliness and support for a circular economy. However, the higher cost and greater environmental impact of production are important considerations to be weighed against the benefits.

For certain applications, PET can offer an excellent alternative, especially where durability and longevity are priorities. When considering PET as a monomaterial for artificial turf, it is important to carry out a full lifecycle assessment to fully understand both the environmental impact and performance requirements.

Making artificial grass circular is a complex process that goes beyond simply recycling the material at the end of its useful life. To make artificial grass truly circular, several aspects must be considered throughout its life cycle, from production and use to final recycling or reuse. Here are some key factors and strategies that determine when artificial grass can be considered circular:

• Design for Recycling: A fundamental aspect of circular artificial grass is the design. The product should be designed with recyclability in mind, meaning it should ideally consist of mono-materials. This greatly simplifies recycling processes as it eliminates the need to separate different types of materials.
• Use of Recycled Materials: Circular artificial grass should consist of recycled materials where possible, and after use, the material should be able to be converted back into new products. This is in line with the principle of the circular economy where materials are kept in a closed loop, minimising the need for new raw materials.
• Sustainable Production Processes: The production of artificial turf should be energy-efficient and use renewable energy sources. This reduces the carbon footprint during the production phase and contributes to the overall sustainability of the product.
• Longevity and Maintenance: Artificial grass should be durable enough to ensure a long life without significant degradation of quality and functionality. Proper maintenance also plays a crucial role in this as it can extend the lifespan and delay replacement, leading to less material wastage.
• Reuse and Recycling at the End of Life: At the end of its life, artificial grass should be fully recyclable, or it should be able to be reused in other applications. Companies and organisations must set up facilities and processes that allow artificial turf to be efficiently collected, processed, and transformed into new products.
• Validation by Life Cycle Assessment (LCA): An LCA can be used to evaluate the environmental impacts of artificial turf throughout its life cycle. This helps identify areas for improvement and ensures that the product complies with circular economy principles.
• Market engagement and Certifications: To promote transparency and trust, artificial grass should meet recognised environmental standards and be certified by relevant bodies. This helps consumers and businesses make informed choices based on sustainability criteria.

In practice, artificial grass is circular when it integrates the above criteria at every stage of its life cycle. This requires a holistic approach to design, production, use and end-of-life treatment, with each step aimed at minimising waste and maximising material reuse. The goal is to create a closed loop where artificial turf never becomes waste, but a continuously reusable resource.

Life cycle analysis is a methodology to assess the environmental impact of a product throughout its life cycle. This includes all stages from raw material extraction, production and use, to end-of-life, including recycling and waste disposal. For artificial grass, an LCA analyses specific aspects such as energy consumption, greenhouse gas emissions, water consumption, and impact on biodiversity.

Why is LCA important?

• Clarity on Environmental Impact: An LCA provides a clear and objective picture of the environmental impact of artificial grass. This allows manufacturers to verify environmental claims and back them up with concrete data, contributing to greater transparency towards consumers and policymakers.
• Comparison of Materials: By performing an LCA, different materials such as polyethylene, polypropylene, and PET can be objectively compared on their environmental performance. This helps make informed choices about which materials are most sustainable for specific applications.
• Innovation and Improvement: The results of an LCA can encourage producers to innovate. For example, if the production phase is found to have a significant impact, new production methods or materials can be developed to reduce this impact.
• Policy-making and Regulation: Governments can use LCA data to develop more effective regulations and policies aimed at reducing the environmental impact of synthetic turf products.
• Marketing and Communication: For companies, an LCA is a powerful communication tool to customers looking for sustainable products. This can be an important selling point in a market where consumers are increasingly opting for environmentally friendly options.

Transparency and Trust

One of the biggest benefits of an LCA is that it creates transparency in an industry that is often criticised for its environmental impact. By openly analysing and reporting on all aspects of synthetic turf production and use, companies can build trust with their customers and stakeholders. This trust is essential in today’s business climate, where consumers and companies increasingly value sustainability and ethical responsibility.

Conclusion

Conducting a Life Cycle Analysis for synthetic turf is not only a step towards ecological responsibility, but also a strategic move that can help companies stand out in a competitive market. By assessing the environmental impact of products transparently and fairly, companies lay the foundation for sustainable growth and long-term customer relationships.

An Environmental Product Declaration (EPD) is a detailed document that describes the environmental performance of a product over its entire life cycle, based on a life cycle assessment (LCA). An EPD contains quantitative information about a product’s environmental impact, such as greenhouse gas emissions, energy use, water use and waste generation. These documents are often validated by third parties and are intended to provide transparency to consumers and other stakeholders. EPDs are useful for companies to substantiate their environmental claims and for customers to make informed choices based on environmental considerations.

The term Environmental Cost Indicator (ECI) is sometimes used as a synonym for MCI, especially outside the Netherlands, or may refer to similar concepts where environmental costs are converted into monetary values. The ECI methodology aims to translate the environmental impacts of a product or service into financial costs, which helps stakeholders understand the true ‘cost’ of environmental impact.

Comparison and Usage

• EPD vs. MKI/ECI: An EPD provides detailed environmental data directly related to the product life cycle, while the MKI/ECI converts these data into monetary values. An EPD provides a comprehensive overview, while an EQI/ECI focuses on the economic representation of environmental impacts.
• Purpose of use: EPDs are useful for providing detailed environmental information to customers and meeting certification standards. EPDs are often used to integrate environmental costs into decision-making processes, especially where budgetary considerations are important, such as in public procurement.
• Scope: EPDs are globally recognised and used in a wide range of industries. The MKI/ECI is mainly used within the context of the Dutch market and is specifically aimed at integrating environmental and economic data.

In summary, EPDs, EQIs and ECIs are important tools for measuring and comparing the environmental impact of products. However, they each have their own applications and purposes, depending on the need for detailed environmental information or an economic evaluation of this impact.