During recent discussions with a prospective client looking into in-house solvent recovery, we uncovered a bit of misinformation. The client was a small packaging printer transitioning from water-based to solvent-based inks; more specifically inks containing nitrocellulose (NC). Typically an alcohol/acetate blend is used as a press cleanup solvent with this chemistry and this company was looking into the best way to handle this process that was new to them. What is the truth about nitrocellulose and distillation?
Here’s where the misinformation was introduced. A vendor of a “green” alternative safety solvents had told the printer that solvents containing NC residues could not be safely distilled. This is false. More on that in a moment.
The “green solvent” salesperson also told the printer the unlikely story that their “green” solvent, once used as the printer’s cleanup solution, could be sold to another company as a cleaning product, allowing the printer to avoid classifying the spent green solvent as a hazardous waste. While it is true that under the EPA RCRA statutes waste that can be repurposed and sold as a product avoids the classification as hazardous waste. In reality, most companies require cleaning products to be of a consistent specification to assure quality control. This was something that cannot be controlled by the printer. The printer’s process will certainly vary from day to day based on the mix of their customer’s jobs. Consequently, this would make it impossible to guaranty the chemical makeup of the waste solvent sent to the supposed third party the green solvent vendor promised.
As for the “green solvent” vendor’s comments on distilling waste solvent with NC resides, it is unknown if the salesperson was simply uniformed or dishonest. The alternative “green” solvent was of a type that could not be distilled due to the decomposition of the vegetable-based components in the product blend when heated. Plus, this “green solvent” is super expensive – roughly 5x more per gallon than an alcohol/acetone blend. Thus explaining the enthusiastic and skewed sales pitch of their product as a miracle cure, and their dubious scheme to repurpose the printers spent solvent. As an aside, how is it “green” if it cannot be distilled/recycled?
The facts are flammable solvent process waste containing solvent-based NC Inks are highly recyclable, a process that can be safely accomplished in a PRI distillation system. PRI’s first solvent recovery system was built in 1983 for a packaging printer using NC inks, and since then we have placed more than 1,000 units in Packaging Printers, all operating safely, reclaiming the hazardous waste for pennies on the dollar. When NC is present, we build our equipment with specific components and safeties in place to deal with it.
NC inks are used by Flexographic and Rotogravure Packaging Printers more than any other than any other type of ink due to the photographic quality of printed images possible using this chemistry. Alcohol/acetate blends are the common clean up solution use by these printers due to their relatively low cost and effectiveness as a cleaning agent. Effectiveness as a cleaning solution, low initial cost per gallon and the ability to be recycled make solvents such as acetates and alcohols particularly well suited as the choice of for sustainability by the packaging printers.
If you would like to find out more about reclaiming flammable or combustible solvents contaminated by inks containing nitrocellulose, contact us here and we will send you a PRI Technical Bulletin covering the process.