S22 - Session O4 - Responsible Color: Cultural, environmental, and ethical sustainability - Zero waste nettle ' process optimization to refine nettle into multi-purpose materials: textile fibres and colourants

Authors: Samica Sadik *, Riikka Räisänen

Recent sustainability related policy objectives integrate with biodiversity issues. Current agri-food systems hold potential in diversifying the material basket, whilst novel crops can hold multi-purpose characteristics that can improve resource efficiency. Equally, the textiles and fibre industry could use ecologically more feasible and localized options. Our aim is to develop more sustainable solutions for fashion and textile production by focusing on high performance natural fibres and colourants, and upgrading of materials' values. In this presentation we showcase the various and unique properties of nettle ( Urtica dioica ) , a perennial low-input multi-purpose crop holding economic (Sadik, 2019) and ecological advantages. Nettle is a historical and previously even industrially used fibre crop providing high textile grade fibre and food within the same harvest. The traditional fibre processing method, which starts with water retting, generates soft, shiny and flexible fibres, ideal for fine textiles applications. The optimized water retting combined with microbiological degumming generates residue water that can be used as a fertilizer n or preferably as a source for colourants. In this paper we, in a general level, describe the zero waste process of nettle, and discuss in more detail, the fibre refining methods, and how the optimized steps result high quality fibre for advanced textiles applications. And further, how the retting water side-stream can be refined as colourants for textile and packing applications. The study utilizes nettle stem biomass originating from a farm that currently processes leaf biomass into food-products whilst leaving the stem biomass unused. When selecting the most optimal biomass processing method for fibre refining, cooperation with biocolourant production was found most feasible way to process waste-water from primary retting phase when operating off farm. Our presentation showcases the colour variety obtained from nettle on various materials, and discusses the colour fastness properties and the chemical composition of the dye.