New Paradigm for R&D and Business Model of Textile Circularity

Abstract

Recycling of garments is difficult due to the complexity of blended materials used during manufacturing. There is also the logistics challenge of processing these used materials in cities where there are no factories. Added to all this is the sheer size of this growing problem. Environmental sustainability is an urgent global challenge. We not only need to come up with innovative technologies but also to scale up these innovations rapidly into viable businesses. New research paradigms and new business models are all necessary to materialize technology and innovation into viable and impactful solutions. We share our story of the accelerated development of innovative and scalable solutions in recycling used apparel through a public-private partnership. Our key innovations include a resource-efficient and low-cost hydrothermal materials separation system and an automated, intelligent, and chemical-free mechanical recycling system that enables us to process used garments into high-value raw materials for new clothes as well as new business model for scaling up the garments recycling.

“Everything Old is New Again”—Recycling of Used Apparel.

Appendix

1.1 About the Hydrothermal System

The hydrothermal recycling system. Photos Edwin Keh

The first Hydrothermal Separation System can process about 150 kg of materials a day.

How does it work.

The system consists of 2 pressurized tanks that treat and separate materials. These tanks then discharge the materials into filtration tanks where the synthetic materials are separated from the cellulosic materials. This 2 tank system allows the treatment of materials in tandem by moving pressure and heat back and forth between the tanks.

The hydrothermal system developed at HKRITA is very energy efficient and is a low-cost method to process used materials. The use of heat and pressure as the mechanism for separation is a significant breakthrough.

The recycled synthetic materials are recovered in fiber form. This makes their reuse as valuable material for apparel commercially viable. Using the conventional methods for recycling of synthetic materials, there is a lot of reprocessing involved. Materials are cleaned, melted, and reprocessed back into fiber form by extrusion. These recycling pathways are usually energy and chemical intensive, consuming a lot of water, and weakening the materials in the process. Our hydrothermal system keeps material in fiber form so it is a very short and straightforward way to reuse. It is a very fast process and the pressure, heat, and water use can be reused with minimal loss. What is more, materials separated and recovered in this manner do not seem to exhibit any weakening of fiber strength or performance. The recycled materials can be used as they are for the making of yarns and can be knitted into garments with simple blending of a percentage of virgin material to strengthen the tensile strength of the final yarn. Early trials of the yarn in production are very positive. More than 50% of the resultant yarn and fabrics can be made up of old materials. There is ongoing work to increase the percentage of old material.

The cotton in the processed materials is separated and is recovered in a powdered form. This cellulosic material is too short and powdery to be turned into fiber as is. The material absorbs many times its weight in moisture. So there is ongoing work to use this material as a performance coating material to other fibers, to use this as an aid to irrigation in farming, or as a raw material to make new cellulose-based synthetic fibers. Early work with this versatile cellulose material shows promise.

1.2 The Billie System

This is an intelligent and highly automated mechanical recycling system. The goal of building this system in Hong Kong is to provide a local processing solution to all the available recyclable materials in HK.

The system uses a combination of multiple engineering sub-systems integrated with machine vision tools in a manufacturing and processing plant that clean, separate, and reprocess old materials into new usable yarns. The process is almost entirely automated, completely dry, and can be completed in a very compact area. The Tai Po system can process 3 tons of materials a day.

Collected old garments are first introduced into the system via a series of ozone processing tanks. These tanks kill off over 99% of bacteria, germs, and other harmful microorganisms in the collected material. The advantage of using ozone as the treatment method is that it is a dry process and does not use harsh or harmful chemicals. The cleaned materials are then transported via conveyor belts to operators who remove any hardware on the used garments. These are mostly buttons and zippers. This is the only manual process of the current system. The materials are then sorted and send along in trays. The trays are scanned and separated by robotic arms by material composition and color. The now sorted and cleaned materials are then put in separate bins. Full bins are carried away by Automated Guided Vehicles (AGVs) to a system library. When an order is received for a type of yarn, the system selects the appropriate material composition in the appropriate colors to be mechanically processed into fibers and twisted into yarns. A percentage (20–50%) of virgin fiber is introduced at this point to improve the performance of the new yarn, and also to improve the new color and appearance. New yarns go through a secondary cleaning and sterilizing using UV lights. The produced yarns are comparable to new yarns in appearance and functionality and usually cost less to produce. Since no water or chemicals is used in this production process, the new yarn has a much reduced carbon footprint.

A video of the operations of the Billie System can be found here https://thebillieupcycling.com.

1.3 The Garment to Garment Retail Shop

The garment to garment (G2G) shop in the mills, Tsuen Wan, Hong Kong

The G2G retail shop is a retail recycling experiment that is being conducted inside the Mills Shop** Mall. Here customers are asked to bring their old garments and watch as workers turn their old garments into fiber and then spin this back into yarns and 3D knit new garments. The idea is to use raw materials provided by customers to make new clothes.

1.4 Conventional Recycling Methods

Mechanical Recycling—the mechanical shredding and reconstitution of used materials. Used garments and fabrics are fed into shredding machines that turn these back into loose fibers. The fibers are then either reconstituted into nonwoven materials (for example, various insulation materials), or these are then combed, carded, and spun back into yarns for woven or knitted applications. The disadvantage of mechanical recycling is that materials are damaged and fibers are shortened when being pulled apart so the value of processed material is lessened. Various performance characteristics are also weakened, and in general the material will feel coarser.

I took these pictures in a recycling factory in Zhuhai China in 2018 showing the processes of used apparel recycling:

• 1. Cut up pieces of used apparel are fed into a shredding machine

• 2. Materials are then pulled apart by progressively finer shredding machines till they are totally disentangled and are reduced to fiber form

• 3. When they are in this loose fiber form they are then either used for nonwoven applications. This particular factory makes yarns for knitted garments, so in this case the fiber is combed and carded so that the fibers are oriented in the same direction.

• 4. The fiber from the used material is twisted and blended together with a percent of virgin material, to improve hand feel and tensile strength. The material is then twisted together into yarns.

• 5. Yarns are then twisted together and pulled to finer and finer as tension is tighten to improve yarn strength. Fine yarn is then finally put on cones and these are now ready to be knitted or woven into new fabrics and apparel.

See also this interesting video https://www.youtube.com/watch?v=AjHVMhAOZa4.

Chemical and Biological Recycling—Chemical and Biological recycling is not as interesting visually. Materials are processed in vats of liquids (usually large steel tanks), various chemicals or enzymes are used to separate and breakdown materials. These are then dried and reprocessed

Chemical Recycling

https://www.chemistryworld.com/features/recycling-clothing-the-chemical-way/4010988.article.

https://greenblue.org/work/chemical-recycling/.

http://greenblueorg.s3.amazonaws.com/smm/wp-content/uploads/2018/05/Chemical-Recycling-Making-Fiber-to-Fiber-Recycling-a-Reality-for-Polyester-Textiles-1.pdf.

Biological Recycling

https://www.youtube.com/watch?v=PfLQdC4VqWg.

This is a video of a biological recycling method we developed at HKRITA

Question

• 1. How can research teams breakdown research silos and work closer with each other?

• 2. Are there other circular solutions to consider?

Future Readings

About the H&M Foundation. https://hmfoundation.com.

About the Novetex Billie System and Novetex. https://thebillieupcycling.com.

About HKRITA. http://www.hkrita.com.

About HKSAR’s ITF. https://www.itf.gov.hk.