Overview of Inks and Varnishes
Inks and varnishes are a necessary part of many functions in society including communications (such as newspapers), culture (such as magazines), products (such as labeling and packaging), and more. With the incredibly massive printing needs of the United States alone, it is no wonder that many have become greatly concerned with the effects of this printing on the environment and on the health of those who work in printing.
For most inks and varnishes, one of the primary considerations in environmental friendliness is the volatile organic compounds (VOCs) each emits. Petroleum-based inks, for example, emit high levels of VOCs making them harmful to the health of those working around them and for the ozone layer as well.
Some pigments are made using metals, which can be very harmful to those who breathe around the inks. And the pigments often require regular harsh chemical cleansers for removing the paint from the printing cells, posing a secondary hazard to worker health and the environment. There are several inks and varnishes that have some redeeming environmental qualities.
Starting with soy-based ink, it is the most used of all inks for newspaper printing and is one of the most popular for other commercial printing. VOCs are much lower than that of petroleum-based inks. But the problem is that manufacturers of soy inks can be deceptive. Even if only 1% soy oil is used, an ink can be called soy based, so it is vital to examine the source before buying soy oil.
UV inks help prevent damage to the environment as they do not require heated drying and put out very little VOCs. They use fewer solvents but are not from renewable sources, unlike the soy. Other vegetable-based inks are also selected for their renewability as well as the ease of cleanup and de-inking, which reduce expense and the use of harsh cleaners. But once again, these inks can be deceptive, containing petroleum products.
UV coating is used like ink and is cured by ultraviolet light. However, UV coating makes it hard to recycle and requires extra energy use for the UV lamps and increased need for cooling the building. Aqueous coating is applied over and ink job to prevent smearing. These coatings are affordable and are great for recycling. They also do not need toxic chemicals for cleanup nor heated drying.
Lamination can be done by using film or a liquid laminate. Applied and dried much like a varnish, the liquid laminate is effective for preventing loss of color and for strengthening the page. But varnish recycles while laminates do not. The laminating process emits high levels of VOCs. Laminated pages are also very hard to de-ink.
While the purpose of the printing is the primary consideration for most printers, it is vital that environmental considerations be taken into account, to make the printing industry more and more accountable for its impact on the earth. Being knowledgeable about the options can help a printer make an educated decision.