While this trend has been going on for quite a long time, the interest in producing a “green” ink is as keen now (maybe keener) as it was during the soybean sticker inks of the mid ’90s.
The NAPIM report then explains ways to increase the environmental friendliness of ink and explains why some popular ideas aren’t actually making ink more “green.” The NAPIM report also explains that soybean oil is not applicable to all types of ink but is partially limited to oil-based offset ink. This article will focus on the vehicle portion of these types of ink.
Let’s listen in on a conversation between an ink maker and a varnish maker:
Ink Maker: “I need to make a green ink so I need to buy a green varnish.”
Varnish Maker: “How green does it have to be.”
Ink Maker: “Green is green, isn’t it?”
Varnish Maker: “Some raw materials are greener than others.”
Ink Maker: “You’re the varnish maker, if you say it’s green then my ink is green.”
Varnish Maker: “OK, I’ll make it as green as I can and shoot you a sample.”
Now, as a varnish maker, I go off and make the varnish “greener” by reducing petroleum solvents and increasing soybean oil. I than have a varnish that is “greener” than…..what?
What we need, as an industry, are definitions that will allow us to gauge the “greenness” of a resin, wax, oil, varnish, flush or ink. Inksolutions has begun to quantify how green the varnishes are we produce.
Before I explain the system we are developing, I would like to pull one more quote from the NAPIM statement:
“Soybean, linseed, tung, safflower and other vegetable oils are all clearly renewable resources while petroleum oils are not. Therefore, the use of vegetable oils of any type will reduce the demand for petroleum oils in the printing ink industry.”
I point this out because our system considers all of the seed/vegetable oils renewable non-volatile ingredients and, as such, “green.”
Table 1: Inksolutions Green Score.
In this scale the lowest score, 0, means that the product uses all volatile solvent and no seed oil. The highest score, 200, means that the product uses all seed oil.
This is all done by subtractingpercentage of VOCs and adding percentage of SOCs:
GS = Green Score
VOC = % Volatile Organic Content
SOC = % Seed Oil Content
Therefore:GS = 100 + SOC – VOC
A formula consisting of 100% volatile ink oil would be:
VOC = 100
GS = 100 + 0 – 100 = 0
A formula consisting of 100% vegetable oil would be:
VOC = 0
SOC = 100
GS = 100 + 100 – 0 = 200
A formula consisting of:
Modified Phenolic Resin40
would result in:
VOC = 20
SOC = 37 (70% seed oil in Alkyd Resin)
GS = 100 + 37 – 20 = 117
Inksolutions has applied this system to all of the varnishes it produces to obtain this information. Here is a partial list of products (Table 1):
This information can be useful for a number of reasons: besides allowing an ink formulator to pick greener vehicles, this information can be carried through to an inkformula or a blend of vehicles.
A vehicle’s green score can be used to calculate the green score for any blend of vehicles, or an ink, without knowing the vehicle’s formula. Algebra tells us that the calculation for the green score (GS) requires two variables (see above).
Using a known green score, the VOC content of a vehicle and the percent of seed oil (which may be calculated if unavailable) the green score formula can be applied to any blend of vehicles or an ink.
Table 2: Comparison of formulas to determine Green Score.
Now, using the Green Score information, a formulator can easily see that formula B is a greener ink than formula A.
This information can then be balanced with the results of printing tests to determine the best performance at the highest green level.
Developing a Clearer Picture of ‘Greenness’
This method, which is in its infancy, has plenty of room for enhancement. With the cooperation of suppliers and ink makers, the more producers who report VOCs and SOCs of materials that go into finished inks, the more refined the results will be. In the above example, every unfilled box in the VOC and SOC column that can be filled in will give a better picture of the greenness of the finished ink.
In addition, you can see that additional variables can be used. This would allow for ideas like raw materials which are not 100% renewable or any other green considerations. The idea of a “scoring system” is to be able to make improvements and to communicate to all involved people what is going on.
Armed with this data, we can clearly make progress that satisfies our customers and helps our supplier focus on the right issues.
Inksolutions is dedicated to helping the environment, not unlike any other responsible manufacturer. We feel this system will help advance our industry’s ability to demonstrate our continued efforts to help the environmental demands of the ink manufacturing and printing industries.