In Part 1, we gave you views of practical people in industry and the academic world about how realistic, sustainable critical cleaning processes may develop over the next five years; we covered many ideas including process design, energy efficiency, and congruent chemistries.1 Let’s
move on to organic solvents, regulatory policy, and hope for peace on earth.
The majesty of the ‘and’
Organic solvents and organic-based process fluids are a mainstay of industry. We think solvents for liquid/vapor phase degreasing will continue to be used in 2020, particularly where a high degree of wetting is needed to remove thin film and particles from miniature components and from complex structures, like those produced using 3D printing. We’ll go out on a (short) limb and say that “classic” solvents will remain under regulatory scrutiny.
Dr. Donald Wuebbles, Professor, Department of Atmospheric Sciences and the Department of Electrical and Computer Engineering at the University of Illinois at Urbana-Champaign, is an expert in atmospheric chemistry and climate issues. Wuebbles sees a trend toward “continuing emphasis on compounds with low ODP (ozone depletion potential) and low GWP (global warming potential) for use as solvents, degreasers, and in related processes.” He expects some HFCs (hydrofluorocarbons) to be phased out due to their higher GWP. However, Wuebbles takes a pragmatic view; he indicates that, in contrast with what he sees as the position of some policymakers, “the ODP should not have to be zero.” He views continued use of a compound “that has an extremely small (negligible) effect on stratospheric ozone” as a realistic approach.
There are promising new solvents. “Industry can’t wait until 2020,” explains David Cooper, Global Business Director for Honeywell in Morris Township, N.J. “The drive toward higher environmental and safety requirements will only grow, both in the U.S. and globally,” asserts Cooper. “We see industry making changes now.”
Cooper explains that “it’s the majesty of the ‘and.’ Whereas industry was once forced to choose between effective cleaning or environmental preferability, there is now global pressure for solutions that provide effective cleaning and environmental preferability; worker safety and cost-effectiveness. Industry cannot accept yesterday’s tradeoffs.”
Azeotropes
“I’m banking my research on blended solvents, particularly on azeotropes (constant-boiling mixtures),” explains Dr. Darren Williams, Associate Professor of Physical Chemistry at Sam Houston State University in Huntsville, Texas, “because you can tailor the composition to meet the requirements of the process.”
Williams directs a laboratory focused on practical aspects of cleaning chemistry and cleaning verification. Williams explains that azeotropes “give us the promise to achieve process consistency and can be fine-tuned in terms of chemical and physical properties to achieve fluids that are safer for workers and the environment.” Williams adds that “where chlorinated solvents are essential, if an azeotropic blend were to allow us to use 30% chlorinated solvent rather than 100%, it would be a great improvement.”
Williams cautions that in developing alternative solvent blends, issues such as VOC levels and flammability must be considered. He adds that, because cleaning processes involve chemicals, equipment, and product, evaluation in a relevant manufacturing environment is essential. “Everyone is trying to pick the demon they are trying to avoid (VOC, halogen, etc). Blending will help expand the range of options, but there are only so many choices,” concludes Williams.
Processes
Many cleaning process techniques could improve the safety and environmental impact of chemicals. Anselm Kuhn, Manager at Finishing Publications Ltd., Stevenage, U.K. predicts that increasing regulation on chemicals will favor the use of more physical energy including high pressure water and CO2 ice blasting technology. He also sees “an increase in the use of ultrasonic cleaning to boost the effectiveness of mild cleaning agents as well as the use of intelligent ultrasonic tanks that regulate power in order to save energy.” We might add the hope that chemical containment, such as in well-sealed solvent systems, be visited as an option within the next few years.
Steve Derman, President of MediSHARE Environmental Health & Safety Services in Santa Clara, Calif., explains that process change has to be holistic and coordinated. “If you were going to do something to improve the safety of a process, the change has to be integrated into the process. For example, in solvent vapor degreasing, adding cooling coils lowers worker exposure, minimizes air and water pollution, and increases efficiencies.” Derman recalls, however, that when the concept was first introduced, “there was reluctance from industry because of increased costs and higher maintenance activities. Industry was pleasantly surprised at the decreased evaporative solvent losses.”
Robotics
Kuhn sees that one consequence of the increased worker safety and environmental regulations might be the increased use of robots. “Robots are progressively being more and more widely used in industry, mainly because of the labor (and thus cost) saving they can bring. I could easily imagine an entirely new phase of robotization based on the premise that their use would allow a process to be carried out, which would be prohibited if human beings were involved.” Building on the approach used in decommissioning nuclear power plants, Kuhn could envision “a sealed production plant or part of a plant where chlorinated hydrocarbons can be used as if they were water. No human beings routinely work in such a plant, just the occasional supervisor wearing an airtight suit. There are no emissions from the building even though the concentrations of organics inside might be quite high.”
World peace—or at least detente
“Can general manufacturing safety and sustainability be improved? Absolutely. The U.S. is quite capable of improving manufacturing. Will things change any time soon? That would be challenging,” asserts Jason Marshall, Director of the Cleaning Laboratory at the Toxics Use Reduction
Institute (TURI) at the University of Massachusetts Lowell. “It’s too big for any one president to decide. Any move will have to be a long-term activity. There will be baby steps contrasted with pressure from other countries who make things cheaper.”
Business and regulatory pressures are global. Across the EU, Kuhn sees growing resentment from industry in that regulations may emanate from “what are seen as faceless European Union bureaucrats in Brussels. The view is that regulations are enacted without thoughts on implications of use of alternatives. There is concern that REACH may have become excessive; for example, boric acid is now registered under REACH. Restrictions on use of hexavalent chromium are just about manageable. Many fear that next in line is nickel. This will cause dynamic tension to increase.”
Tony Revier, Past President of the National Association for Surface Finishing (NASF), adds that “a lot of people would have predicted that the plating industry would be gone by now. But it’s still here, because plating serves an essential role in certain crucial products; and, by being engaged and proactive, NASF has been essential in getting that message across.”
It seems to us that all too often, the relationship between regulatory world and the world of manufacturing is adversarial. Derman suggests that “if regulators and regulatees could work together, the collaboration would make for a more effective situation, one that would improve worker safety, be more protective of the overall environment, be sustainable, and foster technology and manufacturing.”
References
1. B. Kanegsberg and E. Kanegsberg, “2020 Vison: Green, Safe, and Sustainable—Part 1,” Controlled Environments Magazine, October 2014. http://digital.cemag.us/controlledenvironments/october_2014#pg20
2. For additional insight from contributors to this series, please see “Clean, Green, Safe, and Sustainable” in the November 2014 issue of Clean Source, the BFK Solutions newsletter. http://bfksolutions.com/sustainable-2020
Barbara Kanegsberg and Ed Kanegsberg (the Cleaning Lady and the Rocket Scientist) are experienced consultants and educators in critical and precision cleaning, surface preparation, and contamination control. Their diverse projects include medical device manufacturing, microelectronics, optics, and aerospace. Contact: [email protected]
This article appeared in the November/December 2014 issue of Controlled Environments.
