Even though they’ve only recently entered the spotlight, soy-based inks are not a new phenomenon. Inks made from vegetable oils were popular before the 1960s—primarily for newspapers—because of their environmental benefits. However, they were supplanted by cheaper and more cost-efficient petroleum-based inks, which proved costly to both workers’ health and the environment. But soy inks have made a comeback, being increasingly specified by environmentally conscious print buyers. In fact, as long ago as the late 1980s, soy inks for sheetfed presses began showing up on the market. But are they any good? What are the pros and cons of soy inks?
Why Soy-based Inks?
Petroleum-based solvents emit VOCs (volatile organic compounds), which have been linked to certain health risks; VOCs also contribute to smog. Soy-based inks, however, release less than one-fifth of the amount of VOCs emitted by petroleum-based inks. And considering less soy ink is needed for adequate printing, this means petroleum-based inks emit 70 percent more VOCs than soy-based inks for the same amount of printing.
The second benefit of soy-based inks is environmental. Unlike petroleum, soybeans are a renewable resource. Producing soy inks also requires only .5 percent of the total energy needed to produce petroleum-based inks, and soy inks are biodegradable. And since they spread further, soy inks leave fewer ink containers to dispose of in landfills.
Soy ink also is easier to remove from paper, so the paper fibers are less damaged during de-inking and the resulting recycled paper is brighter. It is possible to reuse soy-based inks by mixing used black ink with unused color inks. This lowers the cost of waste disposal and reduces the volume of waste as well.
Of course, soy-based inks are not a perfect solution. First, soybean oil is only the vehicle, not the pigment, in soy inks. Particles of coloration suspended in this oil, such as the heavy metals zinc (found in white inks) and barium (found in red inks), can still be quite toxic. They leach into the groundwater and contaminate the soil if the used ink is not adequately discarded.