Alcohol Replacers and IPA

Alcohol replacers were developed and generally accepted into use in the 1970’s as a replacement for isopropyl alcohol in the press ready mixture. Alcohol replacers, like isopropyl alcohol, are used in combination with a fountain concentrate to deliver a very thin and even water film across the plate surface on continuous type dampening systems. Many printers choose to eliminate the major disadvantages of isopropyl alcohol, including its health and environmental concerns, the increased cost of constant replenishment and its flammability.

Alcohol replacers are basically composed of solvents such a glycol ethers and surfactants. They are normally used at 1/5 to 1/10 the level of alcohol which correlates to approximate levels of 1 to 5 ounces/gallon depending on type of press, dampening system and numerous other variables.

Some key areas to look at when eliminating alcohol are:

1. Roller Hardness (i.e. durometer): Isopropyl alcohol will remove the plasticizers from the rubber, causing the rubber to harden. The harder a roller is, the less its ability to evenly carry a liquid. The durometer of the roller should be in the low 20’s when going off of alcohol. One caution about alcohol replacers is that some products will cause the roller to swell.
2. Grindlines: During manufacturing, rubber and chrome rollers are cut down to specific diameters. During this process, lines are created on the roller’s surface. Many times isopropyl alcohol will “bridge” these lines whereas alcohol replacers may not but will require rollers to be polished and/or desensitized. Roller settings may need to be adjusted or in some cases the rollers may need replacement.
3. Inks: Over the years inks have been formulated to work with alcohol. To ensure a smooth transition to alcohol replacers an ink may have to be reformulated. It is important that ink and fountain solution suppliers work together for optimum performance.
4. Press Condition: Older presses may have more mechanical problems such as roller bounce and vibration. Alcohol helped cover up these problems and complete elimination may be difficult in some cases. Current alcohol replacers have come a long way in eliminating alcohol from the pressroom. The conversion from alcohol to alcohol replacers must be accepted and committed to by press operators and supervisors if the change is to be successful.

RBP Aquanol® vs. Isopropyl Alcohol (IPA)

The following information documents the relative safety of using our AQUANOL products containing 75% 2-butoxyethanol (EB) versus isopropyl alcohol (IPA) in press fountain solutions.

Please keep in mind we refer to the working fountain solution because this is the solution that is in question; not the concentrated material in its container, but the diluted version.

To understand the comparison, one must consider relative concentrations, vapor pressures, boiling points, flash points and physical hazards.

1. Concentration of EB vs. IPA

   Typically in one gallon (128 ounces) working fountain solution four (4) ounces of AQUANOL would be added. The final concentration of EB in this working solution would be 2.3%.

   If IPA were used in place of AQUANOL, then in one gallon of working fountain solution there would be an average of 25 ounces IPA added to reach a concentration of 20%.

   Therefore, the concentration of IPA would be approximately nine (9) times more than EB.

2. B. Relative Vapor Pressure and Boiling Point of EB and IPA

   	EB	IPA	Comment
   Vapor Pressure (at 68° F)	88 mm Hg	31.2 mm Hg	IPA is 35 times greater than EB
   Boiling Point	340° F	180° F	IPA significantly lower than EB

   Volatility is a function of vapor pressure and boiling point. The more volatile a substance, the higher its vapor pressure, and the lower its boiling point. Consequently, IPA is far more volatile than EB.

   As a result, the pressroom will fill up with IPA vapor quite readily because IPA is used in a large concentration compared to EB, IPA has a lower boiling point compared to EB, and IPA has a much higher vapor pressure than EB. Also as the temperature in the pressroom increases so does the amount of IPA vapor in the air. Due to its low vapor pressure, high boiling point and low concentration, EB would not be a hazard to anyone when used in the prescribed amounts.

   Due to the physical properties of IPA, as stated in the previous paragraph, the working fountain solution would have to be replenished quite regularly with IPA due to evaporation loss.

3. Flash Points of EB vs. IPA

   Flash point is defined as the temperature at which a liquid gives off a vapor sufficient to form an ignitable mixture with the air near the surface of the liquid. The flash point of EB is 157° F open cup; the flash point of IPA is 60° F open cup. NOTE: The open cup method approximates actual conditions. Because of IPA’s low flash point – well below room temperature – a fire and explosion hazard exits with its use. On the other hand, EB has a flash point much higher than room temperature; hence, the hazard is minimized when EB is used under normal operating conditions.

4. Hazards of of EB vs. IPA

   IPA presents a fire and explosion hazard due to its physical properties. It is also known that IPA is absorbed through the skin at a faster rate than EB. The danger associated with this absorption characteristic is that IPA is a carrier solvent which means any foreign material dissolved in IPA will be carried through the skin membrane at a faster rate than EB. This presents a health problem to the people handling it. Again, the greater the concentration of IPA, the greater the health hazard it presents.

   EB is a known skin irritant, and presents a significant health hazard when used as a concentrate.

   Safety precautions should be used when dispensing either of these materials.

We at RBP Chemical Corporation are proud of the high quality of products. We are concerned with the welfare of our customers and strongly feel that the use of our AQUANOL® products does not present a hazard when used in prescribed quantities, label directions followed and handled by properly trained personnel.