In light of the negative social and environmental impacts of the textile industry, a paradigm shift towards a more circular economy is inevitable. Automated textile sorting embodies a crucial but missing link to connect forward and reverse supply chains for circular economy, however scalability challenges exist. Therefore, the study explores how dynamic capabilities can overcome scalability challenges specific to automated textile sorting pilots in Northwestern Europe to create commercially viable solutions. A single case study using an abductive approach guided by the dynamic capabilities view explores automated textile sorting pilots’ approaches to dynamic capability microfoundations. Primary data include semi-structured interviews, which is complemented by secondary data documents, and both were analysed qualitatively via thematic analysis. The data reveal that known scalability challenges remain and new scalability challenges related to market disruptions exist, such as COVID-19. Scalability challenges are overcome through novel approaches to the microfoundations undergirding dynamic capabilities. These are found to take place in a continuous, overlapping process, and collaboration is found across all dynamic capabilities. As collaboration plays a prominent role, it should be integrated in approaches to dynamic capabilities. This study also adds to the literature on circular economy in the textile industry by confirming that known scalability challenges for automated textile sorting pilots remain, and new scalability challenges are developing in terms of market disruptions. Actors in the automated textile sorting supply chain may use these findings to support efforts to scale up automated textile sorting. For textile industry brands and recyclers, the findings can assess their readiness to participate in the automated textile sorting supply chain and support the achievement of their 2030 goals to use greater volumes of sorted textile waste fractions as feedstocks for their production processes and to be a collaborative member of the used textiles supply chain.

With the growing demand for sustainable options, the existing sorting capacities are limiting the potential for fiber-to-fiber recycling. With the help of near-infrared spectroscopy (NIRS), automated sorting of textiles with high accuracy is possible due to the easy access for polymer identification. Despite the effectiveness of NIRS, some limitations of the process still limit its full potential. Possible disruptors may interfere with and disturb the identification of polymer identities and compositions in different ways. In the following thesis, additives, treatments, and other environmental factors that may hinder fiber identification are further acknowledged. The key results of the thesis state that stains and factors due to wear and tear are the most common possible disruptors that could be identified from pre-sorted post-consumer end-of-life textiles. Further on, stains of ketchup, deodorant, and oil affect the polymer recognition by lowering the recognized fiber content. Water-repellent coatings on 100 % polyamide woven fabric were not detected correctly according to the NIR scanner, as the stated polymer composition was >90 %. Even though some investigated factors, e.g., material structures, were correctly identified by the NIR scanner, the internal deviation of the knitted polyester structure indicates that porous and loose structures hold the ability to interfere with the detection of polymers. To what extent the operating software has been developed is highly relevant to the outcome of how accurate textile sorting may be.

The textile industry is linked to several major environmental problems, as a consequence there is an interest at European level to reduce the impact of the industry. In Sweden there are several initiatives to increase the circularity of textile for example by promoting fibre-to-fibre textile recycling. To facilitate this type of recycling the SIPTex project was created to build an industrial automatic textile sorting facility able to offer the high-quality sorted fractions required for fibre-to-fibre recycling. This study developed a quantitative analysis to assess the composition of 1.5 tons of post-consumer textile. The results showed that 52% of the analysed material were high-quality fibre garments - mainly cotton,19% lower quality fibre blends and 28%, uncategorizable garments and items not suited for the sorting facility- as shoes or oversized pieces-. The results will contribute to optimize the material inbound in the SIPTex.

Textilindustrins miljöpåverkan är hög, samtidigt som efterfrågan på textilfibrer ständigt ökar. Inom de kommande åren förväntas textilåtervinningen i Sverige att öka vilket skulle skapa en mer cirkulär resursanvändning som på så sätt kan minska tillverkningen av jungfruliga fibrer. För att återvinningsprocessen för de förbru- kade textilierna ska fungera optimalt krävs en sorteringsmetod med hög säkerhet i materialurskiljning. Inom kriminaltekniska områden används märkvätskor för att märka upp värdefulla föremål. Märkvätskorna baserade på metallsalter skapar unika sifferkoder som kan avläsas med en laserteknik kallad LA-ICP-MS. Om ett märkt föremål blir stulet och sedan återfinns av polisen kan märkvätskan avläsas och kopplas tillbaka till ägaren via en databas. Genom att applicera den osynliga forensiska märkvätskan på textilier var projektets förhoppning att skapa spårbarhet i det textila ledet med fo- kus på att underlätta sorteringsprocessen i återvinningsstadiet. Detta genom att skapa en säker märkning som sitter kvar under textilens hela användarfas. Märk- vätskan som användes i projektet kom från SmartWater Technology Ltd som är det ledande företaget i England inom forensiska märkningar. För att simulera en användarfas för ett bomullsplagg har testmetoder för färghär- dighet mot tvätt samt nötningshärdighet utförts. En extern analys utfördes på Smar- tWaters laboratorium i Telford, England, för att kontrollera om koderna gick att avläsa efter de utförda testerna. Testmetoderna har utförts utefter antagandet att metallkoderna har bättre härdighet än den fluoroscensiska färgen. Vid slitage inne- bär detta att färgen avlägsnas vid ett tidigare skede än metallsalterna, vilket resulte- rar i att kodens placering blir omöjlig att hitta utan dess färg. Under detta projekt har därför den fluoroscensiska färghärdigheten varit i fokus. Resultatet som erhölls från nötnings- och tvätthärdighetstestet analyserades under UV-ljus i ljusskåp genom att jämföra färgförändringen mot ett referensprov. En 5- gradig grå-grå-skala användes för att omvandla färgavvikelsen till numeriska vär- den, vartefter matematiska beräkningar utfördes för att kontrollera statistisk signi- fikans. Studien visade att märkvätskans fluoroscensiska färg försämras i takt med antal tvättar. Färgen försämrades något i jämförelse med referensprovet efter nöt- ning, men ingen signifikant skillnad kunde utläsas mellan provkropparna efter ökat antal varv i Martindalemaskinen. Analysen genom LA-ICP-MS kopplade samtliga provkroppar till korrekt applicerad kod vilket tyder på en säker avläsningsteknik. Baserat på tidigare nämnda resultat förväntas märkvätskan därför klara av en an- vändarfas för exempelvis ett ytterplagg eller en möbel i bomull. Fler tester krävs dock för att säkerhetsställa hur vätskan håller efter tid och ytterligare antal tvättar. Lasertekniken som användes för att avläsa koden är säker, men behöver utvecklas eller bytas ut för att en snabbare sorteringsprocess ska erhållas. / The environmental impact for the textile industry is already high and with an in- creasing demand for textile fibers something has to change within the industry. The textile recycling in Sweden is expected to increase in the coming years, which would create a more circular resource utilization, thus reducing the production of virgin fibers. In order to create an optimal recycling process, a secure sorting method is required in material separation. To be able to track valuable objects within the forensic area, a compound based on metal salts is used to mark the objects. The metal composition can be translated into a specific and unique code with a laser method called LA-ICP-MS. The code can later be connected to a person or an organization registered within a database. This thesis examines the possibility to apply the forensic marking compound on a textile carrier to create a trustworthy traceability within the textile chain that is difficult to remove. Instead of register a person or an organization to a code, the vision was to connect a code to a material or a chemical content within the textile product. The forensic marking system used in this thesis came from SmartWater Technology Ltd, which is the leading company in England within forensic coding. A quantitative study was made to research how the forensic coding system based on metal salts acted on a textile carrier. The researched problem was based to ana- lyze the suitability to use a forensic marker system on a textile carrier with the aim to create traceability within the textile industry and to ease the sorting process. To be able to investigate the problem a simulated phase of use was made. Test methods were performed to analyze the impact of abrasion and the ability to with- stand washing for the forensic marking. An external analysis was made at Smart- Waters laboratory in Telford, England, to examine if the metal salts were de- codable, even when the forensic marking was in a bad condition. All the tests and analysis was made with the supposition that the metal salt coding had a better ad- hesion to the carrier than the fluorescence color. Since the coded area cannot be found without the color, the results have been based on the change in color of the fluorescence marking solution. The conclusion shows that the fluorescence colorfastness was decreasing with the number of washing cycles. Number of cycles in Martindale was not significant for a decrease in colorfastness. The LA-ICP-MS method was able to decode all of the samples and connect them to the applied codes. This indicates that the forensic marking system is durable and can be used to mark a garment or a piece of furni- ture that’s not washed a lot. However, more tests are required to ensure how the solution lasts over time and additional amounts of laundry. The LA-ICP-MC meth- od is secure, but one problem is that it’s stationary and therefore difficult to use in a sorting process.