This blog highlights differences, including advantages and disadvantages, between chemical and mechanical textiles recycling via a set of questions.

This is the next article in my textiles recycling series. Part 1 made the case for textiles as a feedstock for recycling so that fewer clothes are thrown away. Part 2 explained chemical recycling and showcased companies that are recycling textiles through chemicals means, and part 3 focused on mechanical recycling techniques such as shredding, melting etc.

I am often asked the following 5 questions.

Q1) Is the quality the same between the virgin and recycled fiber?

It depends on the type of recycling, and the type of fiber

Mechanically recycled natural textile fibers, such as cotton and wool, are weaker than virgin fibers. During recycling, the fabric is cut and shredded, which results in a shorter fiber, and that means a weaker yarn. Fabrics made with shorter fibers tend to have a different visual than fabrics made with long virgin fibers.

However, mechanically recycled synthetic fabrics such as polyester and nylon produce recycled fibers that are almost identical to their virgin counterpart, both from a strength and visual perspective.

If chemical recycling is used, which is common for fabric blends such as cotton/polyester, the recycling process creates both cellulosic pulp and chemicals called monomers. The pulp can be made into manmade cellulosic fibers, such as viscose rayon, and the monomers can be made into new synthetic fibers. The resulting yarns are the same as their virgin counterparts.

Q2) Can I recycle blended fabrics?

Yes, but there are caveats.

Blended fabrics can only be recycled via chemical recycling. Luckily, there are several start-up companies that are developing new ways to separate fabric blends using chemical means. We just need to create the business case so that we can bring these incredible innovations to market!

There has been limited success using mechanical recycling on a blend of 98/2 cotton/spandex denim. However, the resulting cotton fiber is contaminated with spandex, which may impact its ability to be spun into a yarn. Bonded Logic makes UltraTouch denim insulation from blue jeans to insulate walls, but it is not clear if it includes spandex.

Q3) Will hazardous chemicals be in recycled fibers?

It depends on the chemical and we really need more studies.

Mechanical recycling does not remove dyes or other chemicals that are intended to be present on apparel. It is no secret that some of these chemicals are hazardous, which is why implementing good chemical management practices during textile manufacturing is so important. It is therefore possible for the recycled fiber to contain hazardous chemicals.

H&M and Ikea collaborated on a large study that tested for chemicals in recycled cotton. Eight chemical classes were identified as being “possibly present”, and APEO’s and extractable chrome were found in a small percentage of samples. The only conclusion that can be drawn is that more research is needed. I would strongly encourage the next study to include synthetic fibers as well.

Chemical recycling completely transforms the textile. During recycling, dyes and other chemicals can be removed and recovered. Theoretically a new textile fiber can be made using safer chemicals, which is one of the principles of circular fashion.

Q4) What are the advantages of mechanical textiles recycling?

• It is not as energy intensive as chemical recycling
• Sorting by colour can eliminate dyeing, thus saving time, resources and cost
• There is some existing infrastructure. For example, recycling denim scraps is achieved at scale.

The biggest challenge is that mechanical recycling cannot recycle blended textiles, of which there are many.

Q5) What are the advantages of chemical textiles recycling?

• Blended fabrics can be recycled. This means less sorting, and more importantly, provides an option for all textiles.
• Recovery of textile chemicals can be achieved during the recycling process.
• The resulting fiber will be exactly the same as its virgin counterpart

The biggest challenge is that chemical recycling is very energy intensive and still in its infancy in the textile industry.

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.