Recycling is the act of taking waste and making it into a new material that has value, thereby preventing that waste from entering the landfill.

Many different materials can, and SHOULD be recycled, including plastics, paper, metals etc.  Creating new fibers from textile waste closes the loop and supports the circular economy. Recycled fibers can be made using chemical and mechanical recycling processes and there are pros and cons to each. However, scaling the recycling of textiles has a myriad of issues, and opportunities, which include the need for improved fabric sorting, and better separation of fabric blends.

Textile recycling, the available waste streams, and the different recycling processes can be further explained in the examples below.

Mechanical recycling

Mechanical recycling takes waste and recycles it into a secondary material without changing its basic structure. Some common mechanical techniques for textile recycling include shredding fabrics and melting and extruding plastic fibers such as polyester.

Fiber recycling using cotton as a waste stream

Textile cotton waste can be mechanically processed into recycled cotton in the following way

1. The fabric is first sorted into different fiber blends. Ideally, the fabric should consist of 1 fiber although some 98/2 cotton/spandex fabrics are mechanically recycled.
2. Fabric or garments are separated by color.
3. The fabric is cut and shredded and then pulled apart into fibers
4. Prior to spinning, the recycled fibers are disentangled and aligned using a carding process
5. The recycled cotton fiber is usually spun with virgin cotton or polyester to improve the quality because recycled cotton has short fiber lengths and is weaker than its virgin counterpart.

Many denim companies are including some recycled cotton in their product offering. For example, all Mud Jeans contain a percentage of recycled cotton.

Recycled polyester – mostly from plastic bottles

Most recycled polyester in apparel and footwear originates from plastic water bottles, and not polyester textile waste. This is possible because polyester and plastic bottles are both made from a plastic called polyethylene terephthalate (PET).

Plastic water bottles are an excellent waste stream because:

1. There is an abundant supply
2. A “collection infrastructure” already exists in many parts of the world.
3. Plastic bottles are fairly clean. They are often clear, do not contain pigments, and have relatively few chemical additives.
4. Plastic bottles are a cost effective waste source.

Recycled polyester from bottles is made using the process outlined below.

1. Bottles are separated by plastic type and sorted by color. Only PET bottles can be used to make polyester, therefore sorting into plastic type is critical.
2. The PET bottles are shredded into flakes.
3. Dirt and contaminants are removed from the plastic by washing.
4. The shredded plastic is dried thoroughly to remove excess water that cannot be present during recycling.
5. The plastic flakes are made into small consistently shaped PET pellets.
6. The pellets are melted and extruded into a recycled polyester fiber.

Unifi, an American polyester producer, has been very successful with its Repreve® fiber, a recycled polyester made entirely from plastic bottles.

Chemical recycling – depolymerization

Chemical recycling uses a series of chemical processes to recycle a waste stream back into building block chemicals, called monomers. Many industries, including apparel and footwear, use the resulting monomers to create new chemicals and materials. The recycled products are exactly the same as their virgin counterparts, which means that performance is not lost through the recycling processes.

Fabrics that contain more than one fiber are inherently difficult to recycle through mechanical means because the fibers cannot be easily separated. However Worn Again and Ambercycle developed chemical recycling technologies that can separate fabric blends to create textile waste streams that can be further processed into recycled products, including recycled fibers.

Fiber recycling using nylon as a waste stream

Econyl®, a recycled nylon yarn manufactured by the Aquafil Group, is regenerated from old fishing nets and other textile waste using the following process.

1. Fishing nets and other nylon waste is collected and sorted
2. A cleaning and shredding process creates small pieces of nylon.
3. Depolymerization occurs through a series of chemical reactions that convert nylon pieces into nylon monomers.
4. Econyl® is created by polymerizing the monomers back into nylon.

Fiber recycling using cellulose fibers

Chemical recycling using solvents can turn cellulose fibers into a liquid pulp. Once dissolved, the pulp can be used in the viscose process to make manmade cellulosic fibers. However today wood pulp is the preferred feedstock for viscose due to technical and quality reasons, although research continues to make progress.

Do you need help with your circular strategy?

For help with sustainability, circularity and chemicals, contact Amanda Cattermole at (415) 412 8406 or Amanda@cattermoleconsulting.com. We can help you develop powerful solutions to protect your company and brand reputation.

Tips and Insights contains information to help you make informed sustainability decisions. Each post highlights a particular topic and includes questions you may want to consider for your business.