A brief history of cleaning solvents, comparison and why the 3M Novec HFE Engineered Fluids Solvent is the best solvent for your needs.
In the 1980’s and prior, Freon TF (CFC-113) or Freon TMS (TF + 5.7% methanol) was the workhorse solvent for precision cleaning (and vapor degreasing) due to its high purity, low “non-volatile residue” (what is left behind after the solvent evaporates), non-flammability, good solvency (for most oils, flux and other soils), good employee safety (high TLV/AEL employee exposure), and early environmental safety (not a VOC or smog contributor.) However, it was a slightly weaker solvent compared to other chlorinated solvents (TCE, Perc, 1,1,1 Trichlor).
Then when the CFC’s were banned in 1992 due to ozone depletion factors, AGC chemicals introduced the AK-225 line (AK225 MSDS) of HCFC’s (hydrochlorofluorocarbons) and DuPont introduced the HFC’s (hydrofluorocarbons). The AK-225 HCFC products containing chlorine on the molecule were much better cleaners compared to the HFC’s. Therefore, the AK-225T solvent (boiling point 129°F) was the closest match to the previous Freon TMS (boiling point 105°F) with other very similar chemical and non-flammability properties. However, it did have very minimal ozone depletion potential of 0.02 compared to CFC-113 of 0.8.
At the time, it was the best “drop-in replacement” with reasonable pricing and toxicity values. Much political infighting was taking place at the U.S. Environmental Protection Agency (EPA) with all the chlorinated and other solvents hoping to be the best available, but at the time ozone depletion was the primary focus so EPA said they would allow the AK-225 HCFC but mandated phase out on January 1, 2015.
Compare Composition and Properties:
AK225 HCFC vs. 3M Novec 72DA
3M Novec 72DA (replacement for AK225 due to 2015 phase out)
|Composition||87% 225ca/cb HCFC blend – non flammable inerting properties and limited oil solvency||30% HFE7200 blend- non-flammable inerting properties only, no solvency for oils|
|10% cyclohexane – to increase oils solvency||68% 1,2 trans DCE (chlorinated solvent with inhibitors) – excellent high solvency for non-polar oils|
|3% ethanol – for polar emulsifier soils removal||2% Isopropanol – for polar oils – emulsifier soils removal|
|Non-flammable – needed for vapor degreasing equipment||Yes||Yes|
|Employee safety||50 ppm – ok, but higher is better||200 ppm (that of the 1,2 trans DCE, HFE is higher – again, higher is better)|
|Environmental||ODP 0.02, not a VOC||No ODP (Ozone Depletion Potential), but the 1,2 DCE is a VOC (Volatile Organic Compound)|
|Chemical Stability||Very chemically stable for continued recycling in a vapor degreaser||Very chemically stable for continued recycling in a vapor degreaser|
|Component stability||Not an azeotrope, but very stable with minimal composition change over time||Is a true azeotrope, very stable with minimal composition change over time|
|Hazardous waste from the degreaser?||Only if what you clean off your parts is hazardous. You pay for waste disposal.||Only if what you clean off your parts is hazardous. 3M will arrange for and pay for waste disposal, free of charge.|
|Cost||Lower cost than AK225T|
The evolution of more environmentally friendly cleaning solvents has developed into excellent cleaning chemistries with little to no impact on the environment and employee exposure. Although the EPA push away from chlorinated solvents was difficult, it has led to much safer chemistries with similar cleaning effectiveness and power.
3M Novec HFE Engineered fluids are the solvent of choice for precision cleaning applications using vapor degreasers.