Textile Recycling Primer: Unlocking the Path to Circularity
While our primary technology at NTX deals with waterless textile coloration, we understand that achieving true sustainability in the textile industry requires a multifaceted approach. The holy grail is circularity – a closed-loop system where the same molecules are worn, recycled or reclaimed and reborn into new garments, over and over again, until infinity. Although recycling today is far from where it needs to be, exciting innovations in textile recycling are paving the way towards this vision of circularity.
This article serves as a primer on the various recycling methods of today. From mechanical processes that breathe new life into synthetic fibers to chemical techniques that break down polymers into their molecular building blocks, we’ll explore today’s options and some new advancements. Our goal is to educate and empower you with knowledge about textile recycling, enabling informed choices that contribute to a more sustainable future for the fashion industry and our planet.
Understanding Post Industrial Recycled (PIR) vs Post Consumer Recycled (PCR)
When it comes to recycled textiles, it’s crucial to understand the difference between Post Industrial Recycling (PIR) and Post Consumer Recycling (PCR). Many consumers mistakenly believe that “made from recycled materials” means that the apparel they are buying is made from recycled consumer textiles—like a T-shirt or jeans that have been worn, discarded, and then recycled into a new garment. However, this is rarely the case. The reality is that “recycled” almost never means recycled post-consumer clothing. Most of the time, it refers to post-industrial recycling, or at best, it may include some materials that have integrated post-consumer recycling of plastic bottles.
Post Industrial Recycled (PIR)
PIR refers to materials that are recycled from industrial processes. This includes leftover fabric scraps, trimmings, and other waste generated during the manufacturing of textiles and garments.
Here are some key points about PIR:
- Clean and Easy to Separate: PIR materials are typically clean and homogeneous, making them easier to recycle at scale. They do not have the contamination issues found in post-consumer waste.
- Necessitates Industry to Exist: PIR depends on the presence of manufacturing processes that produce waste. This waste is then collected and recycled back into new materials.
- Source of Most Recycled Nylon: A significant portion of recycled nylon originates from post-industrial waste, which is readily available and cost-effective to process.
Post Consumer Recycled (PCR)
PCR involves recycling materials that have already been used by consumers. This process is more complex due to the need to collect, sort, and clean the materials, which can be contaminated with various substances.
Key points about PCR include:
- Dependence on Municipal Infrastructure: Effective PCR relies heavily on the existence of robust municipal recycling programs to collect and process post-consumer waste.
- PET Bottles at Scale: Currently, only PET bottles are recycled at a meaningful scale in the PCR process for textiles. These bottles are collected, cleaned, and processed into new materials.
- Nylon from Fishing Nets: A small amount of recycled nylon comes from fishing nets, but this is not widespread and often limited to specific initiatives like using nets that have met the end of their lifecycle and have been provided by a fishing fleet. It is a misunderstanding that nets collected from the ocean are used to recycle Nylon – nets that stay in the ocean degrade beyond the point of being able to be recycled.
- Example – Circulose: Companies like Circulose (formerly RenewCell) are exceptions, focusing on recycling post-consumer textiles. However, most “recycled” cotton in the market still comes from post-industrial recycling.
The following chart from National Institute of Standards and Technology illustrates that much less than 1% of post consumer textiles can be considered fiber-to-fiber recycled in the US.
Mechanical vs. Physical/Thermal vs. Chemical Textile Recycling
In the pursuit of textile circularity, three distinct recycling approaches have emerged: mechanical, physical and chemical. While all aim to breathe new life into textile waste, their methodologies and outcomes differ significantly.
Mechanical Recycling
Mechanical recycling involves mechanical processes such as shredding and re-spinning fibers. This method is relatively simple and cost-effective but typically results in downcycling, where the recycled fibers are of much lower quality than virgin fibers/filaments/yarns. Mechanical recycling is often used for materials like polyester obtained from industrial waste, which can be reprocessed into products like insulation, carpet or seat cushion fill, and low-grade textiles.
Pros:
- Low cost.
- Relatively agnostic to source.
Cons:
- Lower quality fibers that are only suitable for downcycling.
- Can not be used for the same original use.
Physical/Thermal Recycling
Physical or thermal recycling involves melting and re-extruding PET waste into new fibers or products. This method is particularly suitable for thermoplastic fibers such as polyester, nylon, and polypropylene. The process involves a degree of molecular level adjustment thus it is capable of producing high-quality fibers that are close to virgin quality.
Pros:
- High-quality recycled fibers.
- Efficient for thermoplastics.
Cons:
- Stringent requirements for clean polymer source (ie, uncolored beverage PET bottles).
- Not suitable for non-thermoplastic fibers.
This technique has been popular for the past 20 years, but it faces a few challenges. The biggest issue is sourcing, which typically relies on single-use plastic bottles. There is competition for this source from bottling manufacturers, who are increasingly required to use recycled materials. Additionally, the infrastructure for this recycling method is limited to certain regions. While Taiwan, Japan, South Korea, and Germany have the necessary facilities, costs associated with managing recycling in Germany have risen. China remains the largest source of recycled PET. Moreover, regulatory bodies now mandate that for textile products to be labeled as made from recycled goods, the input materials need to be textile-based – nullifying physical/thermal recycling for textile purposes; thus adding complexity for textile manufacturers.
Chemical Recycling
Chemical recycling goes all the way, breaking down polymer chains into their chemical building blocks (monomers) through a variety of processes; popular methods are hydrolysis, glycolysis, or methanolysis. This method allows for the recovery of original monomers, which can be purified and re-polymerized into virgin-quality polymers. Although more complex and capital-intensive than mechanical recycling or thermal recycling, chemical recycling can handle a wider variety of textile waste, including mixed and contaminated fabrics while resulting in true virgin grade fibers/filaments.
Pros:
- Produces virgin-quality fibers.
- Can process mixed and contaminated textiles.
Cons:
- Generally higher cost and complex process.
- Requires significant capital investment.
Chemical recycling is considered true recycling (closed-loop) because it breaks down polymer chains and re-polymerizes them into original lengths, making the final product chemically indistinguishable from virgin materials. While, in theory, raw materials can come from any source, practical limitations exist.
Main Methods of Chemical Recycling
DMT PROCESS VIA methanolysis is an older method that involves breaking down PET into dimethyl terephthalate (DMT) through methanolysis followed by high energy distillation to purify DMT monomer. This is then followed by esterification with monoethylene glycol (MEG) to produce PET.
Some key aspects of this process include:
- Pure PET manufacturers find this process too expensive.
- It’s more feasible for chemical suppliers who also produce polybutylene terephthalate (PBT), which is used for industrial application such as power sockets, because having two polyester outputs lowers costs.
- Economically viable when PET is a byproduct.
PTA Process is a newer method that requires recrystallization, making it low-energy and more cost-effective. Circ is one company that has made great strides in this technology and are in the process of building out their first commercial plant.
Some key aspects of this process include:
- Hydrolysis followed by low energy recrystallization to purify, followed by esterification with MEG to PET.
- Thermal Hydrolysis processes can handle mixed stream impurities in the input stream more easily, simplifying the process and improving the economics of recycling.
- Pre-treating mixed material inputs can make the PTA process more efficient, reducing costs and allowing the use of post-consumer recycled materials.
Key Facts and Misconceptions About Textile Recycling
We are still far from achieving circularity in the textile industry. Meanwhile, there are many misconceptions and cold facts about recycling worth pondering:
- “Made from recycled materials” almost always means that a product contains a small percentage of recycled plastic bottles, not textile material that has been recycled.
- One garbage truck of textiles is thrown away every second.
- There are 100 billion garments produced annually, and 92 million tonnes end up discarded in landfills.
The Importance of Accelerating Our Way Towards Circularity
To mitigate these issues, it is crucial to accelerate our efforts towards true recycling and circularity. Real recycling—such as fiber-to-fiber recycling—enables the continuous reuse of materials, reducing the need for virgin resources and minimizing waste. By supporting and investing in advanced recycling technologies, we can move closer to a sustainable and circular textile industry. This shift not only helps the environment but also promotes a more responsible and conscientious fashion industry.