How is recycled nylon made?

Although Aquafil does not reveal the production process adopted by them for the manufacturing of Econyl, a certain outline process can be understood which includes waste collection and depolymerising it to extract nylon and then transforming it into a yarn.

The Econyl Reclaiming programme is the first step in the production process that includes waste collection such as fishing nets, fabrics and fluff from carpet flooring. The next step is the cleaning process wherein the foreign material such as metallic and plastic debris are removed and only nylon-6 is left behind. Also, many recycled materials melt at a high temperature which destroys the contaminants but nylon requires low temperature thus the foreign debris is left behind and cleaned nylon is obtained.

Once the cleaned nylon is obtained, the next step is depolymerization. This step involves shredding and breakdown of extracted nylon into its monomers. However, it is unclear what chemicals are used in the breakdown process and whether the chemicals are toxic or not. The caprolactam obtained has the same chemical and performance characteristics as those obtained from fossil fuel. The monomers are then rendered into a molten polymer solution which is then extruded through a spinneret (a sieve-like device with holes). This follows the process of drawing wherein the fibers are stretched to impart strength and wounded on to the spool. The fibers are then treated with a certain finish application as per the end-use. The fibers may be processed into BCF yarn (carpet flooring yarn) and NTF yarn (textile yarn).