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 the unintended consequence of this labeling scenario is that the lower volatility solvent might have caused the printer to choose the chemical that creates a greater risk to health and a greater environmental impact. Interestingly, the law in Europe has changed so that the exposure scenario is an integral part of the information on a material safety data sheet (MSDS) and will help guard against this type of problem. The new legislation is known as REACh (Registration Evaluation & Authorization of Chemicals), and it became effective June 1, 2008.
The main point is that you must carefully assess the MSDS of any cleaning solvents you are considering. Remember to ask the manufacturer as many questions about what is not on the MSDS as about what is on it. If specific sections are blank, find out why.
There is a further and important consequence of labeling of solvents as harmful under EU regulations. Many highly volatile, lower-cost solvents, such as toluene, cyclohexanone, mineral spirits, etc. are classified as harmful by inhalation. There are other harmful solvents that are classified as harmful by ingestion. Clearly, the distinction is important in the context of screen cleaning where inhaling a highly volatile solvent represents a very real risk, as opposed to the more theoretical risk of ingesting the solvent. Our processes are hands on and the operators are close to the evaporation. Therefore, a careful study of the MSDS is essential to confirm which category of harmful the raw materials fall into.
We don’t encourage the use of harmful solvents. But there are times when economics make it very hard for a printer to choose a label-free solvent, particularly if the shop is using an ink that requires a more hazardous formulation to effectively remove the ink from screens. In those cases, the printer should be encouraged to go for the lowest volatility that works to minimize the risk to staff and waste to the atmosphere.
Bringing green to the reclaiming room
This discussion concentrated on screen cleaning that occurs on press, where printers expect specific performance properties from cleaning chemicals, such as slower evaporation and leaving no oily residue. The requirements of the chemicals used here differ from those used in the screen-reclaiming process, in which printers need chemicals that have good water miscibility so that they and stencil residue can be easily rinsed away. In the next part of this series, we’ll address those products and the consequences of disposing of reclaiming chemicals down the drain.
Author’s note: My thanks to the other MacDermid Autotype employees who contributed valuable information for this article, including Simon Jones, commercial manager, and Dr. Sem Seaborne, regulatory affairs compliance officer.
Neil Bolding is MacDermid Autotype’s business-support manager. He is a 25-year veteran of the printing industry with experience in quality control and technical customer support. He has written articles for a variety of trade publications, spoken at numerous industry events, and regularly contributes to SGIA training programs. He currently sits on the SGIA’s Environmental Committee and the Membrane Switch Council. In 1994 he was the industry co-chair (product- testing subcommittee) for the US EPA’s Design for the Environment Program. Bolding also is a member of the Academy of Screen Printing Technology.
Professor Steven Abbott is technical and research director at MacDermid Autotype, Wantage, England. After receiving a PhD in chemistry at Oxford for work he carried out at Harvard and serving in a post-doctoral position in Strasbourg, he went to work at ICI on new product development. In his role as research and technical director of MacDermid Autotype, Abbott has been responsible for ensuring a constant stream of new products and also for providing the science behind the coating and printing techniques used. He frequently collaborates with researchers at the University of Leeds, where he serves as a visiting professor, and is a frequent speaker at international conferences related to coating and printing. Abbott is a recipient of the Swormstedt award for technical writing from the Specialty Graphics Imaging Association.
Did you enjoy this article? Click here to subscribe to the magazine.