TEAM: Heidi Turunen (Aalto University)
All sorts of cellulosic materials or wooden materials, which are mostly cellulosic, have been dyed by using natural colours. Dyed material samples were nanocellulose in form of film and sphere, pine wood, birch veneer, pulp sheets, pulp fibre filaments, yarns and fabrics made from cotton or flax. Colour sources were for example birch, lupine, nettle, onions, tancy, webcap, madder and cochineal. Colourants have been added to boiling water. Mordants were used, enabling color to be attached to the cellulosic materials.
Different types of tones were possible to generate and hues were soft and natural. Intensity was modified by the time the materials were soaked in the natural colours. Shade of the samples were almost equal despite the cellulosic materials used. Nanocellulose dyed remarkable well, and intensity of the tone increased due to shrinkage.
Natural colours were fasten by using suitable mordants for each dyestuff, due to this, lightfastness might be relatively good. So far materials dyed by using natural colours have maintained intensity.
Colour sources from nature could be the one natural way to dye cellulosic or wooden material in industrial level in the future. Application areas could be almost everywhere where cellulosic materials are used. Those areas can be, in addition more conventional textile dying industry where natural dyes have been used widely in the past, for example industrial products, interior decoration applications, but also products related to the construction industry and architecture.
Photos: Eeva Suorlahti