I recently had the pleasure of chatting with Gary Jones, Vice President of Environment, Health and Safety Affairs at the Printing Industries of America, the largest graphic arts trade association in the U.S. As you can imagine, Gary is one of the most knowledgeable people on the face of the planet when it comes to the environmental impact of printers’ inks. And what he had to say about soy ink was nothing less than eye-opening.
Here’s an excerpt from our conversation:
Anne: There’s a popular conception that soy inks are generally better for the environment than petroleum-based inks. Is this true?
Gary: At the heart of the issue with soy inks is that they were not designed to be greener than conventional inks. They were designed to maximize the amount of soy oil that could be formulated into an ink.
The term “Soy inks” was coined by the American Soy Association. In order for an ink to use the orgnization’s Soy Seal logo, it only needs to contain the specified amount of soy oil or soy oil derivatives. No other specifications regarding the other components of the ink are identified.
For example, in order for a heatset web offset lithographic paste ink to be considered a “soy ink”, it must have 7% soy oil content. Why 7%? Because if soy oil were present in any greater concentration, the ink would not dry. Therefore, a heatset litho ink that contains 7% soy oil and 93% of other ingredients such as methyl ethyl death would be considered a “soy ink” and can carry the Soy Seal logo!
Anne: So, you can think you’re being green, but actually get a product with very little renewable content.
Gary: You have to understand that there are many different types of inks, formulated for different purposes. There’s a huge variation in the percentage of soy that can be successfully used in any given type of ink.
The most common and most noted use of soy oil is in offset lithographic inks – the kind used in commercial printing. So the term soy ink generally refers to these inks.
If you look at the way the American Soy Association has their Soy Seal set up, the amount of soy oil required in order to call an ink a “soy ink” varies by type of ink. It’s based on the total percent of the weight of the ink. For example, sheetfed offset lithographic inks must contain 30% soy oil, and inks for printing newspapers or news inks must contain 40% soy oil in order to qualify under the Soy Seal trademark program.
Anne: There’s a popular conception that “Soy ink does not contain hazardous substances.” Yet you say it can. What are some of the chemicals commonly found in soy ink?
Gary: The biggest misconception people have is that all of the components of soy ink are made from soy.
What else is in inks? The basic components ― besides the ink oil, which is considered the ink solvent ― are pigments to color the ink and make it opaque; resins and film formers (which bind the ink together into a film and to the substrate that will protect pigment from rubbing off ); and additives, such as waxes, slip agents, and in some inks, a catalyst to assist in drying.
Offset inks are a paste ink, a very thick, viscous ink. They dry by absorption and oxidation. Once the ink is applied to the paper, the non-drying oil quickly drains into the surface as the ink sets. Then other components of the ink ― resins and film formers ― dry and form a film to protect the pigment. Heatset web offset lithographic inks (ed. note – used on coated paper such as magazines and newspaper inserts) dry by evaporation, so they can’t contain so much soy oil or they’d never dry.
In terms of the pigments, there are many choices, but the more common one for black is carbon black which is organic. Yellow is diarylide yellow which is also organic. Red pigments are barium based and blue is copper phthalocyanine. The catalyst can be cobalt or manganese based. Linseed oil and other renewable ingredients are often used as part of the varnish, which is the clear porting of the ink that contains the resins, solvents, film formers and additives.
Anne: What about Volatile Organic Compounds (VOC’s)?
Gary: Soy inks do have a lower VOC (volatile organic compound) content and since soy is used to replace the mineral oil, we’re increasing the renewable content of the ink.
But it’s important to realize that VOC content and VOC emissions are two different things. The EPA has a specific test method, Method 24, that is required to be used to determine VOC content. A sample of ink is heated at 110 centigrade for one hour and the amount of weight lost is considered the VOC content, after being adjusted for water and exempt compounds. Using that method, there’s less VOC in soy ink.
However, vegetable oils, including soy oils, will auto-oxidize, which means they absorb oxygen from the air and that oxygen cross links at certain points in the vegetable oil to cause it to dry. When the vegetable oils cross link, they can actually gain weight and in this process of oxidation they produce and emit VOCs in the form of alcohols, ketones and aldehydes. So in reality, even though the actual measured VOC content may be lower, it’s not uncommon to see a higher veggie oil content resulting in more VOC’s actually being emitted.
Anne: Is it true that soy inks are better for paper recycling?
Gary: That’s a case of “Don’t believe everything you read online.”
Soy inks are harder to recycle than their conventional counterparts. It’s all over the Internet that soy inks are “easier to recycle,” because of a preliminary bench top test performed in a major university laboratory. Soy released more organics, so they assumed it’s easier to recycle. But they did not take the aging of the ink or actual recycling processes into account.
Several additional studies have shown that aged soy ink is much harder to remove than conventional. A large contributor is the oxidation and cross linking that occurs in the drying process. While soy oils are not the best drying oil, they do and can crosslink.
In short, the research wasn’t bad, it just wasn’t complete. It wasn’t a full evaluation, but people ran with it.
Anne: Would you say that soy inks are more environmentally friendly?
Gary: That’s a loaded question with no easy answer. While soy oil is renewable, one of the important questions is – where is the soy oil coming from?
While some is produced domestically, much is sourced from many other parts of the world, including razed rain forest areas that have been converted to agricultural plantations. Plus, the distance that the oil is shipped adds to the environmental burden. If it is shipped literally halfway across the world, the impact will be much greater. I have not seen any life cycle assessments to indicate that soy inks are preferable.
Anne: Are you aware of any inks that are produced 100% domestically, in the U.S.?
Gary: Most ink that printers use is formulated here in the US. The best mineral ink oil is domestic, made from Pennsylvania crude. But like anything else, it’s a worldwide commodity. Where does the gas that goes into your tank come from? There are two main suppliers of (fossil-based) ink oil and like many other products, they’re going to buy where they get the best price. Same with soy oil.
Anne: Are there “greener” inks out there? What would you recommend as an environmentally friendlier choice in inks?
Gary: So what you really want to know is, ‘What do I do now that you’ve ruined my entire concept of soy ink?’
From a sustainability perspective, you want to use inks with the highest percent of renewable resource possible, sourced from a sustainable operation. However, you have to be aware of the ecological price you pay for that renewable resource. That’s the challenge and you may have a trade off because if you have an ecosystem that you destroy in order to create a monoculture – what’ s better? That or a nonrenewable resouce? In many instances, the answer is not always clear.
The thing that we have to be careful of is to reserve making value judgments. Everyone wants to know, what’s better – this or that. And I don’t know if we’re in a position to say what’s better. It’s hard to make comparisons unless there have been life cycle assessments performed, and they are using the same scope and assumptions. You don’t normally run across that. And of course people see things the way they want to see them though their own lenses and filters.
My advice is: use the inks with the highest renewable resource content and understand the sources of the ingredients. From a global sustainability aspect, the more (renewable content) that’s incorporated the better because that way you’re at least moving in the right direction.
What do you think about soy ink? Do you agree that it’s best to choose it when possible? Does it matter? Why or why not?