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Moisture Sensitivity of Isocyanates
311511G 9
Moisture Sensitivity of
Isocyanates
Isocyanates (ISO) are catalysts used in two component
foam and polyurea coatings. ISO will react with moisture
(such as humidity) to form small, hard, abrasive crystals,
which become suspended in the fluid. Eventually a film
will form on the surface and the ISO will begin to gel,
increasing in viscosity. If used, this partially cured ISO
will reduce performance and the life of all wetted parts.
To prevent exposing ISO to moisture:
• Always use a sealed container with a desiccant
dryer in the vent, or a nitrogen atmosphere. Never
store ISO in an open container.
• Keep the Iso (A) Pump Lube system jar 3/4 filled
with clean Throat Seal Lubricant (TSL) 206995.
Change whenever fluid appears cloudy.
• Use moisture-proof hoses specifically designed for
ISO, such as those supplied with your system.
• Never use reclaimed solvents, which may contain
moisture. Always keep solvent containers closed
when not in use.
• Never use solvent on one side if it has been
contaminated from the other side.
• Always park pumps when you shutdown.
• Always lubricate threaded parts with Part 217374
ISO pump oil or grease when reassembling.
Foam Self-Ignition
Isocyanate Hazard
Keep Components A and B
Separate
Changing Materials
• When changing materials, flush the equipment
multiple times to ensure it is thoroughly clean.
• Always clean the fluid inlet strainers after flushing.
• Check with your material manufacturer for chemical
compatibility.
• Most materials use ISO on the A side, but some use
ISO on the B side.
• Epoxies often have amines on the B (hardener)
side. Polyureas often have amines on the B (resin)
side.
The amount of film formation and rate of
crystallization varies depending on the blend of
ISO, the humidity, and the temperature.
Some materials may become self-igniting if applied
too thick. Read material manufacturer’s warnings and
material MSDS.
Spraying materials containing isocyanates creates
potentially harmful mists, vapors, and atomized par-
ticulates.
Read material manufacturer’s warnings and material
MSDS to know specific hazards and precautions
related to isocyanates.
Prevent inhalation of isocyanate mists, vapors, and
atomized particulates by providing sufficient ventila-
tion in the work area. If sufficient ventilation is not
available, a supplied-air respirator is required for
everyone in the work area.
To prevent contact with isocyanates, appropriate per-
sonal protective equipment, including chemically
impermeable gloves, boots, aprons, and goggles, is
also required for everyone in the work area.
NOTICE
To prevent cross-contamination of the equipment’s
wetted parts, never interchange component A
(isocyanate) and component B (resin) parts.