I have started working on a new project, which involves thermochromic yarns. I have therefore started experimenting with different ways of colouring/dyeing untreated yarn to provide the thermochromic effect, since pre-coloured thermochromic yarn is not something that can be found on the market today.
These initial tests that I am sharing on the blog today are treated by screen printing the thermochromic dyes onto the yarns. The yarns are a selection of different wool qualities as well as a flux.
There are only a few examples to be found by others who have experimented with dyeing and printing yarns with themochromic dyes/inks, some of which you can find in Chapter 2.1.2 ‘Thermochromic dyes and textile construction techniques’ of my Phd. thesis. Chick here to download to read. In my thesis, I also refer to some really interesting research carried out by Dr. Ibrahim. He has demonstrated that it is also possible to screw-extrude thermochromic yarns from ethylene vinyl acetate (EVA), polypropylene (PP) and linear low-density polyethylene (LLDP). The yarn was extruded with powder-based red and blue leuco dyes activated at 31°C (supplier LCR Hallcrest). At the current stage of development, the material is fragile, but the colour change is clear and the colour appears homogenous. However, the material has shown a decrease in colour strength after initial tests in drawing the yarn from room temperature up to 80°C. (Ibrahim, 2012, pp.144-179) Nevertheless, it’s a great start, and I for one was very exited when I got the see and test the yarns.
I see the ability to produce thermochromic yarns by extrusion and dyeing as exciting new design possibilities for the thermochromic material when working with, for example, knitting or weaving, to create new colour-changing structures and patterns.
More on this to come in due course.