The production of polyethylene terephthalate (PET) textiles, commonly known as polyester, is an energy and water-intensive process, particularly during the dyeing and finishing stages, leading to significant carbon emissions and wastewater filled with toxic chemicals. Conventional dyeing processes consume large volumes of water and energy, making them environmentally harmful. Innovative methods like hydraulic spray atomizer offer a more sustainable alternative by reducing water and chemical usage, thus minimizing waste and environmental impact. This study explores the hydraulic spray dyeing process parameters, including pre-treatment, dyeing, pre-drying, and fixation steps for three different polyester fabrics. The objective is to achieve resource-efficient dyeing with comparable results to traditional methods, and to compare effectiveness of a combined pre-treatment and dyeing approach with a two-step spray application of pre-treatment and dyeing. Pre-treatment of the polyester fabrics with chemical hydrophilizing agents by spray application showed to improve the hydrophilic character and wetting capacity of three polyester fabrics—P75, P600, and Kibo based on reduced water contact angle measurements and increased vertical wicking rates. A pre-treatment also showed to enhance the K/S values of the three different polyester fabrics. The addition of a pre-drying step showed some indication of reducing disperse dye migration, and enhanced color strength of the Kibo fabrics. Spray dyed samples maintained dyeing quality comparable to padded samples. One-step spray processes demonstrated comparable or improved color properties and durability to fastness to washing and abrasion in comparison to two-step processes. The results demonstrate that the hydraulic spray atomizing system is viable for both dyeing and pre-treatment of polyester fabrics. Furthermore, this lays the groundwork for innovation in wet textile processes of polyester fabrics using this resource-efficient alternative, aiming towards sustainable textile production and dyeing.

Textilindustrin har under de senaste åren vidtagit drastiska åtgärder för att ställa om till en mer hållbar industri och därav möta målen för Agenda 2030. Denna undersökning syftar till att förbättra den resurssnåla hydrauliska sprayteknikens infärgning på ullvävar med hjälp av två resurssnåla förbehandlingar, plasmateknologi och ultraljudsbad. Färgklasser som används är syrafärg och reaktivfärg. Efter litteratursökning har försök utfärdats för att optimera de båda metoderna med ändamål att en mer intensiv och jämnt fördelad färg ska framträda. Inställningar gällande både ultraljudsbehandlingen och plasmateknologin diskuteras såväl som möjligheten till att effektivisera färgrecepten. Resultaten presenteras efter utförda tester på vätbarhet och färgmätningar innefattandes färgförändring och färgstyrka. Underlagen för signifikanta skillnader är bristfälliga men vissa tendenser på förbättring gällande alla avseenden kan urskiljas, dock utan slutsats om optimala inställningar. Bäst effekt återfinns i färgstyrkan för båda behandlingarna oavsett färgklass. Tas däremot alla tester i beaktande dras slutsatsen att plasmabehandlingen bäst möter de optimala egenskaperna som ullvävarna bör anta för en godtagbar infärgning. Vätbarhet, som syftar till materialets hydrofilitet, visar på betydligt bättre resultat för de plasmabehandlade proverna än för ultraljudsbehandlade, dock inte i den mån för att tillgodose problemet. Trots detta har de båda förbehandlingarna potential till att uppfylla syftet med studien, men ytterligare forskning och vidare tester krävs för att kunna implementera dessa i industrin. / In recent years, the textile industry has taken drastic measures to transition to a more sustainable industry and thus meet the goals of the 2030 Agenda. This study aims to improve the resource efficient hydraulic spray dyeing technique on wool fabrics using two resource efficient pretreatments: plasma technology and ultrasonic bath. The dyes used are acid dyes and reactive dyes. After a literature review, lab tests have been conducted to optimize both methods with the aim of producing a more intense and evenly distributed colour. The settings of both the ultrasonic and the plasma treatment are discussed as well as the possibility of streamlining the colour recipes. The results are presented after performing wettability tests and colour measurements including colour change and colour strength. There is no evidence for significant differences but tendencies for improvement in all aspects can be differenciated, however without a conclusion on optimal settings. The best effect is found in regards the colour strength for both treatments irrespective of dye class. However, if all tests are taken into account, it can be concluded that the plasma treatment meets the optimum properties that wool fabrics should adopt for an acceptable dyeing. Wettability, which refers to the hydrophilicity of the material, shows significantly better results for the plasma treated samples than for the ultrasonic treated ones, although not to the extent of satisfying the problem. Nevertheless, both pretreatments have the potential to fulfill the purpose of the study, but further research and testing is required to implement them in the industry.

Background: As a company it is more important than ever to consider the environmental sustainability aspect within the whole supply chain and all the stakeholders. Studies show that people's concerns about environmental sustainability increases and will continue to grow in the future. The wet dyeing process is the part of the textile production that consists of liquor and contains three main steps which are pretreatment, coloration and finishing. This process is presented as the most water, energy and chemicals consuming process within the textile industry and because of that, it is important to investigate it to be able to improve the environmental sustainability.  Purpose: The purpose of the thesis is to increase the understanding of IKEA’s suppliers' current usage of water, energy and chemicals within the wet dyeing process. Followed by an identification of opportunities for improvements in the wet dyeing process, aiming to become more environmentally sustainable.  Method: Through interviews with two suppliers, information regarding IKEA’s current wet dyeing processes will be collected. After that, data from relevant theoretical sources will be collected to analyze possible improvements of methods and colorants that can be relevant for IKEA as well as other companies within the textile industry to implement.  Conclusion: For research question 1, the researchers reach the conclusion that IKEA’s supplier number one has a more environmentally sustainable wet dyeing process compared to the second supplier.. A conclusion is nevertheless drawn that improvements within both suppliers wet dyeing processes should be considered to become more environmentally sustainable. For research question 2, the researchers come to the conclusion that Spray dyeing is the best alternative method to implement for improving environmental sustainability within the wet dyeing process. The researchers also recommend companies to actively become a part of the development of bacterial colorants, the future of coloration.