Inks can be any color these days as long as they are “green.” Without a doubt, sustainability has become a major issue in packaging converting, and much of the focus has been on substrates. We’ve all seen stories that it’s the substrate that takes up a lot of room in those landfills. If it isn’t easily biodegradable, then it better be recyclable.

Many people feel that inks are the next big issue in sustainable packaging. Even though inks constitute such a small part of the package, their impact is huge. After all, inks provide the product’s marketing message. Ink makers and printers need to take note that printing end users are starting to demand that their packaging be printed with inks that contribute to the package’s sustainability. Of course, these inks are expected to perform equally as well at an economical price.

When it comes to packaging, inks and substrates are married to each other. Once the two materials are bound, they are difficult to separate. But it does happen in recycling and in disposal, and the results can contribute to worsening environmental conditions. This is especially true in a country like the U.S., where consumption of packaging is estimated to be nearly 300 lb per person each year.

As far as I’ve seen, no one has defined exactly what a sustainable ink is. However, we know there are a few things it should not be. It should not contain materials that are harmful to human health through exposure or ingestion. Ideally, the inks would allow easy recycling of the package and would not release toxins when buried or left exposed.

Ink formulators are being urged to design inks that do not contain heavy metals such as barium, copper and zinc. This type of pigment has been shown to create worker health hazards and can leach out of the packaging after disposal. Frequently, inks contain a petroleum base, which is nonrenewable. That’s why some end users demand the use of inks based on vegetable oils or water, depending on the printing process. Volatile organic compounds (VOCs) that result from the solvents in inks also are considered pollutants that must be controlled. Additionally, energy-cured inks and coatings are being touted because they don’t contain VOCs and can use less energy in the curing process than heat-dried products.

It’s time to add inks into the sustainability equation. As one consumer product company states in its policy on sustainable packaging, “The solid-waste hierarchy teaches us to first reduce, then reuse and finally recycle.” Those are basic factors that must be considered when formulating or choosing inks for packaging.