In the first installment of this series, you learned why incorporating an environmental management system as part of a broader business plan is becoming an essential part of running any company. Here the discussion continues with a look at on-press cleaning materials and practices with a focus on identifying VOC risks.
So what is a company to do? How simple is it to make a substitution and still have a product that provides good working efficiency? Unfortunately, this particular situation often leads to the use of highly volatile alternatives, most frequently acetone, particularly in areas where the legislation is driving this move. For example, in the South Coast Air Quality Management District of California, acetone is considered a non VOC.
Not only will a highly volatile alternative product such as acetone evaporate very quickly, but it’s also important to remember that if it’s up your nose, it’s not working for you on the screen. This isn’t a very elegant way of stating the problem, but it gets to the heart of the issue of volatile solvents. The good thing about volatile solvents is that they are cheap, and, because they consist of small molecules, they can be very good solvents for the ink. The bad thing about volatile solvents is that, well…they are volatile, which leads to a combination of wastefulness, flammability, and a hazard to the health of the people in your shop.
To make a point about the wastefulness, we conducted a simple laboratory experiment within our company. We took a standard screen, started with a known weight of cloth and solvent, and then cleaned the screen five times by dipping the cloth into the solvent and wiping the screen a set number of times. We then re-weighed the cloth and solvent to see how much had been lost during this process. We used four different solvents. The first was low VOC as defined by the Californian standard. The second was low VOC as defined by the European standard. The third was a solvent we like to use in screen cleaners, which is just above the European VOC threshold. The fourth was acetone.
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