Sorry if I wasn't clear. I got out of printing 10 years ago when the getting' was good. This new product I'm working on is an immersion cleaner in a totally
different industry (automotive aftermarket). End users will be instructed to dunk their partÑsay a carburetorÑlet it soak for an hour or two, and then rinse/spray it off upon removal. There shouldn't be any oily rags.
Shouldn't. But never say "never."
Dan
From: ACS Division of Chemical Health and Safety [mailto:DCHAS-L**At_Symbol_Here**PRINCETON.EDU]
On Behalf Of Monona Rossol
Sent: Friday, August 09, 2019 11:50 AM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: Re: [DCHAS-L] spontaneous combustion of methyl soyate
Well, that's all well and good from a safety point of view, but not from a printingmaking point of view. You want oils that are unsaturated and will spontaneously
combust since you want the reaction that causes that combusting to occur slowly in the ink when it is printed out on paper or textile so it will dry and set up. The heat of the reaction is easily dissipated on the flat paper or textile. Otherwise you have
an unset ink the smears and for a long time, perhaps forever.
You just have to teach them about the reaction and how to handle these rags
Monona
-----Original Message-----
From: Dan Nowlan <dnowlan**At_Symbol_Here**BERRYMANPRODUCTS.COM>
To: DCHAS-L <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Sent: Fri, Aug 9, 2019 12:25 pm
Subject: [DCHAS-L] spontaneous combustion of methyl soyate
In a former life, I used to formulate lithographic press washes. As VOC restrictions tightened, various fractions of mineral spirits, aromatic distillates,
glycol ethers, and terpenes were replaced at first by heavy paraffinic distillates, such as
Paraffinic 100. It was cheap and VOCs only had to be reduced so much. As VOC levels continued to drop, though, more active "solids" were sought in an effort to maintain some semblance of efficacy, and chemicals like t-butylated biphenyls and especially
fatty acid methyl esters (FAMEs) were utilized.
Some of these FAMEs were based on high-oleic acids or occasionally even "fully" saturated starting materials like coconut. Of course, soy methyl ester (SME)
quickly gained traction due to economics, and it didn't take long before printers started experiencing rag fires, similarly to what was not uncommonly seen with D-limonene-based press washes years before. We quickly began adding a solution of TBHQÑthe same
antioxidant that SME manufacturers would typically useÑto our formulas with very high SME content, and the problem went away. We never determined what concentration of SME became problematic or how much TBHQ solved the problem. We went big with the AO and
the rag fires stopped.
Fast forward 10 years, and I'm tasked with formulating an immersion cleaner, which would benefit greatly from the inclusion of SME. While the application
isn't quite the sameÑnobody should be dipping rags into the productÉbut that doesn't mean they won'tÑI'm still concerned with the potential for spontaneous combustion (SC). I can't just add a line item of TBHQ to the formula as we're going to solicit
bids for toll blending, and side mixing a solution of TBHQ to add to the bulk blend isn't practical.
All that ^ is to preface a few questions.
1) Does anyone have any specific information on SC of unsaturated FAMEs that I could peruse? Upstream suppliers haven't been especially helpful, and I didn't see anything particularly relevant on the web at a glance.
2) Where can I find oily rag storage recommendations and/or requirements? I have to assume there's an NPFA standard addressing that. And
3) does anyone have any suggestions for testing the potential for SC in the lab? I have zero analytical equipment and cannot directly test for oxidation or oxygen uptake. Though it doesn't mimic field conditions, I
can cook various mixtures in a standard gravity oven and check for darkening. I can also throw oily rags in a steel bucket and put them in the hot Texas sun, though I do prefer not to start any rag fires if at all possible.
Congratulations if you made it down this far and thanks in advance if you're going to contribute something helpful!
Dan
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