Below are some comparisons of standard plastisol ink contents compared to TSD water-based ink contents. As an obligatory disclaimer, this information is to the best of my knowledge based on what I researched in early 2009.
It’s important to know that not all water-based inks are environmentally friendly and not all plastisol inks are terribly detrimental to the environment. If you’re not printing with TSD, make sure to investigate and verify the composition of your printer’s inks in order to make an enlightened decision. Make sure to get full ink content disclosure from your printer!
There are four basic components of a screenprinting ink:
Pigment – the color. Pigments can either be powders or liquids. Pigments, as opposed to dyes, are not water-soluble.
- Plastisol and some water-based inks often contain heavy metals in order to make them heavier and more opaque or to increase the light- and wash-fastness of the print. Certain Azo-based pigments contain structures that are suspected to cause health problems.
- TSD pigments contain only trace heavy metals by design (less than 100ppm, the same as drinking water), but maintain good light- and wash-fastness because of the printing methods used.
Carrier – the vessel for delivering the pigment to the shirt
- Plastisol inks use a solvent, typically petroleum-based with high VOCs (volatile organic compounds), as a carrier to dissolve the pigment and the binder.
- Our inks use potable water as a carrier, which suspends the pigment in the mixture rather than dissolving it.
Thickener – keeps the ink from bleeding out onto the shirt after being printed
- Plastisol inks typically use a synthetic, petroleum-based plastic polymer as a thickener. The most common thickener for plastisol inks is PVC (poly vinyl chloride), which contains phthalates and other chemical additives that can leech out over time.
- TSD inks use a cellulose-based thickener; in other words, made from wood. It is completely biodegradable.
Binder – binds the pigment to the fiber
- PVC is the standard binder for plastisol inks. The thickener and binder are often similar PVC chemistries.
- TSD inks use a synthetic acrylic binder. While it is not rapidly biodegradable, it contains no vinyl structures or functional groups (e.g. chlorine or fluorine), and is entirely inert (thus non-toxic). Elmer’s Glue® is another example of an acrylic binder, one that is chemically almost identical to our binder.