I’m not going to say too much about the technical aspects of this photo except that the dyes used are off-the-shelf, suitable for domestic use. The dye penetration was about 30% of the cross section, so not complete, but not just a surface effect either. All three lengths of filament came from the same batch and run so started as exactly the same colour (the middle filament).
Obviously nylon takes a colour-fast dye. Some of your clothes are testament to that fact and nylon-centred 3D printer makers Markforged have already shown how they apply that attribute. My research question here was whether it was worth chasing that fact as a saleable attribute in our finished, Fishy Filaments, recycled product.
Dying isn’t something that 3D printing enthusiasts do much, largely because most filaments are made as opaque, containing relatively expensive pigment additives alongside the original body colour. In most plastics that ‘natural’ colour is a neutral off-white. Adding pigments can alter the engineering qualities of 3D printing filaments, as well as the colour, so many of the more technical materials are only sold as ‘natural’ colour.
Pigments don’t mix in the same way as dyes and because they operate by reflecting light off quite large particles they tend to be more UV resistant. Dyes tend to operate at a much smaller scale, molecular rather than particulate, and are a bit more sensitive to environmental exposure. Sometimes the way that a dye is uptaken into a material is a little unpredictable and can be influenced by factors such as surface texture and material density.
Put it another way the two main 3D printing materials, PLA and ABS, often compete on the basis of UV resistance to colour fade and that’s great if you actually want permanence and bulk standardisation. But colours aging is not necessarily a bad thing, especially in highly functional materials used in difficult environments or where a designer would like to take advantage of wear to highlight some aspect of their design.
Controlled reactions to environmental exposure are already used in engineering applications to provide information about part degradation. And who from the 1980s can forget the fashion for distressed denim. Moreover dyes like alazarin, and others, are used in medical tests to provide rapid diagnostics. So the ability to soak a dyestuff into the surface of a 3D printed form could have multiple high value applications.
I’m not a dye chemist, but I do know that dye chemistry is a multi-billion pound industry that employs many cookies much smarter than I.
I’ve only tried one brand of simple domestic clothes dye and it worked well first time. The simple fact that we can open the door to providing a high quality recycled 3D printing material that is open to 4D applications (controlled colour change with age/environmental exposure) can only be a positive and it encourages me to take these tests a little further.
Whether the applications meet the material and a match is made is impossible for me to say. Materials development is all about opening doors to imaginative designers.
Fishy Filaments has just opened another door.