“May you live in interesting times” is a thinly-veiled curse, one that no doubt resonates with manufacturers involved in critical product cleaning. In the United States, current interesting times arise from a confluence of multiple factors. One set of factors is the regulatory activities at the Federal and State level that impact PFAS “forever” chemicals. A second group encompasses regulatory activities under EPA Amended TSCA that is likely to restrict key cleaning chemicals. A third are business decisions reached by suppliers of cleaning chemistries in response to regulatory activities. Notably, 3M recently announced that they will discontinue manufacturing of all fluoropolymers, fluorinated fluids, and PFAS-based additive products. Some manufacturers doing critical cleaning in aerospace, medical, optics, and other high-value product have relatively recently invested time and effort to move to cleaning containing these or similar solvents. The reasoning being that the new processes would have fewer environmental restrictions than classic chlorinated or brominated solvents.
Living in interesting times is a curse. Understanding the details of these challenges to manufacturing is crucial to achieving a strategic response and perhaps to discovering productive opportunities. We’ll begin with forever chemicals, move on to other solvents, and conclude with a few steps you might consider.
Manufacturers may associate PFAS primarily with surface finishing. PFAS (per- and polyfluoroalkyl substances) are also important in cleaning applications.
Recently, 3M, announced a decision to
We should point out that, while the impending loss of the 3M process materials is of concern, it is not the end of the world. Similar products for cleaning applications are available from other suppliers.
Designer Solvent Blends
Given the worker exposure limits set by EPA Amended TSCA, many manufacturers became justifiably concerned about using well-established solvents including perchloroethylene (PCE), trichloroethylene (TCE), n-propyl bromide (nPB), and methylene chloride (MC) as we reported in the July 2022 issue of Clean Source. They looked for a substitute that would have properties that were relatively similar to the chlorinated and brominated solvents they were accustomed to.
While there is no drop-in substitute, trans-1,2-dichloroethylene (trans-DCE) has solvency properties that are relatively similar the classic chlorinated and brominated solvents. Unfortunately, trans-DCE has a low flashpoint. This is where the so-called designer solvents like HFEs, HFOs, and HFCOs come in. While these designer solvents have some favorable cleaning properties (such as high wetting index, rapid drying), they are not effective for solubilizing most soils of interest; and they are expensive, thus the “designer solvent” nickname. They are useful, some might say essential, because they act as a flashpoint inerting agent. They are blended with trans-DCE (the most stable are azeotropic or constant-boiling blends) with one or more designer solvents. The blends are sold under a number of trade names, one informal term is “80/20” blends since that is approximately the ratio of trans-DCE to inerting solvent. In these blends, the trans-DCE provides the heavy lifting in terms of solvency. The designer solvent(s) suppress the flashpoint; and because of their high wetting index, may contribute to cleaning of complex parts and to removal of fine particles. Moving to these blends requires effort and process planning. There are technical issues like cleaning performance, in part because the blends have a lower boiling point than do the chlorinated or brominated solvents. That said, some manufacturers have made the technical effort and financial investment to successfully adapt their cleaning processes to use the 80/20 blends.
No Free Lunch
We’ve told you before; and we’ll tell you again, there is no such thing as a free lunch. The “F” in HFE, HFO or PFAS stands for fluorine. Fluorine in the designer solvents provides the flashpoint inerting properties and also the potential for release of PFAS. Fluorine has a low position in the periodic table, is smaller and has stronger forces when combined with other atoms, so its compounds tend to be more stable. That is why PFAS are stable and long-lasting in the environment.
They are sometimes referred to as “forever chemicals.” There is increasing worldwide regulatory concern about impact on the overall environment (including air, water, and soil) and on human health.
In addition to activities at the U.S. EPA, over a dozen states are in an assortment of phases of regulating PFAS. For example, in Maine, there will be a ban on sales of products with PFAS starting in 2030; there are provisions for some exemptions.
Further, trans-DCE, while it is a promising substitute for chlorinated and brominated solvents, is in itself under scrutiny by the U.S. EPA. It is in the risk evaluation phase. We do not know what EPA findings will indicate. Compared with the chlorinated and brominated solvents that have already been determined to pose unreasonable risks to workers and are in the risk mitigation stage of regulation, there should be a longer timeline for allowed use trans-DCE.
Forever Cleaning Processes
Diamonds are forever in the world of James Bond. However, given the current safety/environmental regulatory actions, cleaning processes are not. There is the suspicion that if a cleaning chemistry is effective, it must be damaging to the workers, to neighbors, and/or to the environment. There is some truth to this suspicion. We are all made up of chemicals. There is a regulatory philosophy of regulating the chemical, not the process. Of assuming that workers may not behave in a safe or responsible manner. There also appears to be a policy of regulating on a chemical by chemical approach. This approach just leads to ongoing, costly process changes.
So, as a manufacturer, what can you do? Be prepared! Stay flexible; and be strategic. What are the technical and economic pressure to change the process? How soon do you have to do so? How long must the process work?
It you switched to an 80/20 blend, were you wrong? Probably not – there were probably good technical, philosophical, and/or political chemistry reasons. However, if you currently use an 80/20 blend, insist on transparency from the cleaning agent supplier. In some cases, the fluorinated ingredient may be subject to change depending on availability. Be sure you are informed in advance of any changes; and make certain the modified blends will work acceptably in your application. Even changes in the inert portion of the cleaning agent can impact certain sensitive substrates. As for the azeotrope, it simply must be stable to assure worker safety and process consistency.
We suggest that you make changes from a position of strength and knowledge, not simply based on vendor claims about cleaning agents. Proactively look at all of your options in cleaning agents. Consider what cleaning processes and cleaning equipment will be needed to use the various cleaning agents.
If your cleaning process is in danger of being disrupted, become truly educated. Everyone is being disrupted, including suppliers of cleaning chemistries. Sales reps may have themselves been disrupted or may soon be disrupted. They may therefore offer their immediate best product fit; it may or may not be the best or only option for your application.
“May You Live in Interesting Times”
3M announcement on fluorinated fluids
Clean Source, July. 2022: exposure limits set by EPA Amended TSCA
General discussion of PFAS
State by state regulation of PFAS
JD Supra is a law firm.
Regulation of PFAS in Maine
Beverage & Diamond is a law firm.
“Maine Bans PFAS Containing Products as of 2023”
Note: Despite the wording of the headline, the ban on sales is not immediate.
HP-1113 – LD 1503
“An Act to Stop Perfluoroalkyl and Polyfluoroalkyl Production”
Note: The rule appears to be geared toward fabric; and there looks to be exclusions where inclusion of PFAS is required by Federal Law.
Good technical reading with the right amount of chemistry/cleaning science. Well done, very informative.
Thanks, Miguel! I’m happy to learn that you enjoyed the article and that you found it useful. Barb K.