Cleaning Agents for Cured and Uncured Urethane
The following is some information on the cleaning agents for
cleaning urethanes. We do not carry these materials. The
recommended suppliers’ links are at the end of the document. Please
contact the suppliers directly. Many cleaning agents have high
volatility and are flammable. Please consult your supplier for the
safety and handling information.
Methyl Ethyl Ketone
This can be used as
a general cleaning material to clean tools, molds, and machine.
Acetone can be used as a cleaning agent, but since MEK has slower
vaporizing rate, MEK is easier to use than Acetone. MEK is still
volatile and flammable. You have to be very careful handling this
material. Make sure you use this in a well-ventilated area.
Dibasic Ester (DBE)
This has low vapor
rate than MEK, and it is not considered to be flammable. (It is
still combustible, which is same flammability as the paint
thinner.) You can use this to soak your lines, machines, and
tools. This material swells the solidified urethane material and
makes it very soft, so it is easier to remove. Since this does not
vaporize quickly, small residual will be left in your line and
machines or mold. You may use MEK or your production resin raw
material (polyol or isocyanate whichever is used in the line) to
flush the small left over after DBE is used. In this way, you can
limit the amount of MEK you use to reduce the fire hazard.
If DBE is not
strong enough, you can look at NMP. Like DBE, NMP has a low vapor
rate. This has stronger solvency than DBE, so it can break down
more persistent urethane stuck in your mold, lines, and parts.
However, the toxicity level of this material is higher than DBE.
So, if DBE works well for most of the parts, you probably want to
stay with DBE. You would probably want to try limiting the use of
NMP if possible. Again, this does not vaporize away; so you need to
flush with MEK or your production resin raw materials to clean.
Small amount of
these cleaning agents should not affect overall properties of your
polyurethane product. However, these cleaning agents sometimes
contain high concentration of water. Lower the water concentration
better it is. Ideally, water concentration should be lower than
0.3% in the cleaning solvent. If it contains high amount of water
in your cleaning agent, be sure to dry the cleaning agent completely
before you start your production.
agent can clean urethane off as well. However, alcohol reacts with
isocyanate component in the part-A material, and it will affect the
quality of your product. Avoid using alcohol cleaning agent where
you cannot be sure it is completely dried.
hydrocarbon materials such as mineral spirits or paint thinner do
not clean polyurethane. Aromatic hydrocarbon such as Aromatic 160
can clean polyurethane. If the odor is not a problem, you may use
aromatic hydrocarbon for cleaning.
If you prefer to
keep the lines of the machine filled with liquid material while the
machine is idle for an extended period, DBE may not be a good
choice, because it can solidify from residual material or may affect
rubber and plastic parts (gaskets and hoses) on your casting
equipment. If you want to keep liquid inside the lines for an
extended period of time, we recommend using mineral seal oil.
Mineral seal oil is less invasive to rubber and plastic parts, and
fairly easy to handle.
You may obtain
these cleaning agents from the following sources. Please check with
these suppliers for your local sources.
questions, please contact Northstar Polymers.
Northstar Polymers, LLC
3444 Dight Avenue South
Minneapolis, MN 55406
April 8, 2011