It’s no hidden fact that textile is the second worst offender when it comes to polluting the planet. The average life time of a garment is roughly three years. More textiles are being dumped after their life cycle and this alarming pollution of landfill is escalating every year. On disposing, the materials try to decompose – some become successful and others end as harmful deposit without being degraded. When the fibre is 100 per cent natural, it might decompose in few years, but the growing population demands more clothing which is estimated to be 99 million tonnes per annum which can’t be met completely by natural fibres.
So, when blends of natural fibres and synthetic fibres are used, which are still mostly petrochemical derived synthetics, it continues to be harmful once disposed in the ecosystem. And the challenge becomes even more critical when garments made from such blends are dumped.
How to perform recycling on the products made from different synthetic and blended fibres?
Just for simplification, let’s see how difficult it is to recycle a down jacket (outerwear jacket), that’s made up of different MMF material or blends. The jackets constitute different material in lining, inner chest pocket, front pockets and fibres inside the panels. All the layers are made up of material such as elastane, polyamide etc. Then come zippers and buttons that are tightly integrated to the jacket. This material diversity when mixed with staple fibre yarns, multilayer materials, highly functional coatings, and prints & dyes pose a great challenges in recycling of such products.
According to Amrei Becker, Textile Engineer, RWTH Aachen University, Germany, such products, made up of man-made fibres of different synthetic blends, can be recycled by using any of these four methods – 1) Mechanical Recycling (Tearing); 2) Thermo-Mechanical Recycling (Regranulation); 3) Physico-Chemical Recycling (Solvent Based Separation); and Chemical Recycling (Back to Oglimer/monomer).
Mechanical Recycling of textiles is the process of recycling the textile fabric back into fibres without the use of any chemicals. This process includes shredding and carding process to extract the fibres from the fabric which can then be spun to make yarn for either woven or knitted fabric. The input material in this recycling is textile made of natural or synthetic fibres that are torn down to individual fibres. In this process, the fibres remain as fibres but their length gets shortened due to tearing and mechanical damage.
The Mechanical Recycling starts with the shredding of the waste fabric into smaller pieces which are then sent to garnett machine – used for opening hard twisted waste – for fibre extraction. These machines perform heavy and rough carding actions by tearing the fabrics with opposite sets of strong sharp teeth transforming it to its component fibres.
Tech Providers:
- France-based LAROCHE S.A is one of the renowned companies that offers technologies to recycle both synthetic textiles and cotton textiles mechanically.
- HKRITA (Hong Kong Research Institute of Textiles and Apparel) in association with fashion giants such as H&M has developed a mechanical garment-to-garment recycling system that acts as a mini production line which can process post-consumer garments into sanitised recycle garments.
Thermo-Mechanical Recycling (Regranulation) is the process in which textiles are shredded, melted, and then re-granulated instead of getting converted into fibres! The input material to perform this process are synthetic, material-homogenous textiles, and, if possible, the recyclers are advised to use such textiles without impurities. The output material is therefore the contaminated pellets of fibres.
Explaining the reason behind contaminated output material, Amrei told Apparel Resources, “In the thermo-mechanical recycling (regranulation), the input material (e.g. synthetic fibres or textiles) are melted, filtered and extruded. If the input material is contaminated, it is possible that the output material (the rPET or re-granular) is contaminated too.”
Citing an example, Amrei said that if you recycle 95 per cent PET, 5 per cent elastane textile in this process, some elastane can be filtered out but some will get into your rPET. Also, additives can mostly, but not all, be filtered out.
Swiss technology group OC Oerlikon’s subsidiary offers cutting-edge solutions for the recycling of synthetic textiles and PET using Regranulation process.
Physico-Chemical Recycling (Solvent-based separation) is a process where desired textile material is separated by means of solvent. The input material here is the mixed material flow of synthetic/natural fibres, depending on solvent and polymer. The textile waste is converted into RePAN-pellets, which undergo spinning method and finally staple fibres are obtained.
Using this method of recycling, waste streams of polymers can be recovered and purified achieving qualities similar to the quality of virgin plastics. To successfully recycle end-of-life polymers and to achieve high-quality polymer qualities using selective solvents, it is essential to remove solvents in the final stage of the process – down to ppm (parts per million) levels.
Tech Providers:
- Switzerland-based Sulzer Chemtech offers its breakthrough DEVO technology to offer solvent-based separation/recycling.
- UK-based Worn Again Technologies has gained some name in this space and is working with textile industry’s stakeholders to provide solutions for physico-chemical recycling
Chemical Recycling (Back to Oglimer/monomer) is the process that is used to achieve polymers of virgin quality. In this, polymers are broken down into oligomers or monomers, which can be rebuilt into a polymer. The output products are most often the same in quality as their virgin counterparts, with no loss in physical properties through the recycling process. This is much superior to mechanical recycling when it comes to technology with the use of chemicals, enzymes, controlled environment etc., for its process thus having added benefit of lesser limitation in the form of fabric such as woven, knits catering to a wide range of products like jackets, auto-parts, home decors etc.
Amrei informed that, depending on the technology, chemical recycling processes have a higher chance to reduce contaminates, but they are also more energy-intensive!
Tech Provider: Italy’s Aquafil Group is one of the leading companies that uses proprietary technologies to produce chemically recycled nylon at commercial scale.
Markus Reichwein, Head of Product Management, Oerlikon Manmade Fibre (a subsidiary from Swiss technology group OC Oerlikon making over 35 million tonnes of man-made fibres annually) has also opined how key sustainability issues in the fashion industry are a threat to the environment. Technologies are doing great job, yet the impact of MMF on planet can’t be overlooked, especially when the use of PET is increasing drastically worldwide.
Speaking with Apparel Resources, Markus further informed that Oerlikon follows Thermo-Mechanical Recycling (Regranulation) technology and its solutions for the same are the Vacufil System and the Homogenizer System. The company is extensively targeting to develop Chemical Recycling (Back to Oligomer/monomer) technology which is, at the moment, only limited to very specific material quality sources such as clean bottle flakes.
“Further, as far as Physico-Chemical Recycling is concerned, it remains our vision to recycle mixed textiles…To fulfill this vision, we have recently invested in a company called Worn Again that uses advanced recycling technology to recapture raw materials from non-reusable products (textiles, PET bottles and packaging) which is being brought to life by technical expertise and strategic partners who have a shared ambition of creating a circular world,” informed Markus.
Markus further said that rPET (recycled PET) can help generate fibres by PET’s conversion and reduce greenhouse gases. “Our recycling technologies with focus on chemical and mixed textile recycling ensure that polyester can be used in a continuous circle without putting it into landfill. This is why we are pushing so strongly for our vision and that’s how one can achieve sustainability through recycling,” concluded Markus.
The need for textile recycling…
Textile consumption is only going to grow now and so is textile waste. And the trend for fast fashion has devastated the market with often use of low-quality material, no reuse and complicated silhouettes which have become a nightmare for further recycling. Thus, without any solution and with the present take-make-dispose model, the industry is inching towards the inevitable to a point when the strain on the planet will get much worse.
Processes/methods/technologies are available but the issue is in implementation of the same. Amrei has also suggested levers to enable effective textile recycling and, as she believes, the onus of the same should be on sorters/recyclers and textile engineer. “Interconnected work by sorters and recyclers across the textile recycling chain is very much required. Along with this, textile engineers should participate, especially in all high quality recycling processes, because that’s what they are qualified for,” mentioned Amrei.