Making the transition to a low-VOC wash doesn’t have to cause undue sacrifice or frustration. The following steps can eliminate some of the problem areas and make the changeover successful.
VOCs (Volatile Organic Compounds) are unhealthy for many reasons—they can harm the environment by helping form smog, which damages crops and forests in addition to being harmful to lungs. Some blanket washes also contain chemicals called Hazardous Air Pollutants (HAPs), which may also harm human health and the environment.
By using blanket washes containing fewer VOCs, you can significantly reduce the impact that your printing operations have on employee health and the environment. You may also be able to reduce your regulatory requirements. To find out the VOC content and other components of your current blanket wash, ask your supplier and check the product’s Material Safety Data Sheets (MSDS). Suppliers can recommend substitutes containing less VOCs.
Press Washes: Solving the problem
History tells us that the best press washes are those that break down and remove ink quickly, evaporate fast, and are easy to use. History also tells us that these traditional washes typically contain 90% to 100% petroleum distillates (VOCs).
Today’s environmental climate and the issuing of increasingly stringent regulations are creating a situation where these traditional, high-VOC washes are no longer acceptable. The current target for low-VOC washes is that they contain less than 30% VOCs (by weight), which equates to approximately 2.5 lbs. per gallon.
The obvious question is how do we move from efficient, high-VOC traditional washes to the more environmentally acceptable low-VOC products?
Unfortunately, none of the alternatives are perfect. The surfactants typically used to formulate emulsion-based washes, if not properly removed, can build up on rollers and blankets, causing poor ink transfer, stripping, and emulsification. The vegetable oil washes often require a rinse step, leave a greasy residue, and are also slow to evaporate. With wash-ups sometimes taking place up to 15 times a day, this can have a substantial impact on production costs. Include periodic deep cleanings using a wash such as Unigraph’s Color Change Wash Setp 1 and 2 to eliminate surfactant build up.
Washes containing exempt solvents are efficient and sacrifice little in productivity, but they present problems and frustrations for the press operator. If you attempt to go from a solvent-based wash to a low-VOC alternative overnight, the most practical and cost-effective approach is to do the changeover in several steps. While reducing VOCs is critical, cost of restarts, paper, and quality of printing must all be considered.
How to make low-VOC washes work
Making the transition to a low-VOC wash doesn’t have to cause undue sacrifice or frustration. The following steps can eliminate some of the problem areas and make the changeover successful. While this procedure doesn’t completely eliminate VOCs, it significantly reduces them without sacrificing cost effectiveness and print quality.
Choose a good quality, low-VOC wash from a reputable manufacturer.
Begin using on rollers. Periodically deep clean them with a traditional two-step colour change wash to eliminate surfactant buildup.
After a period of successful use on rollers, begin using as a blanket wash, always following the manufacturer’s recommended procedures. In cases of unusually difficult cleaning, a traditional wash should be used.
To help avoid problems, continually monitor rollers and blankets. Look for signs of surfactant build-up, such as greasy residue, ink emulsification, poor ink transfer or slow cleanup.
While this procedure does not completely eliminate all VOCs, it significantly reduces them.
To date there are no perfect low-VOC washes. But with a strong commitment and an understanding that these washes perform differently and require more attention, a pressroom can effectively eliminate a substantial percentage of VOC’s from its press washes without sacrificing efficiency and print quality.
The development of higher-performance, more effective low-VOC washes is always continuing—find out which one is right for your shop.
