Isocyanate Conditions
3A0019J 5
Isocyanate Conditions
Material Self-ignition
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.
NOTE: The amount of film formation and rate of
crystallization varies depending on the blend of ISO,
the humidity, and the temperature.
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 lube pump reservoir (if installed) filled
with Graco Throat Seal Liquid (TSL
™
), Part 206995.
The lubricant creates a barrier between the ISO and
the atmosphere.
• 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 contam-
inated from the other side.
• Always lubricate threaded parts with ISO pump oil
or grease when reassembling.
Keep Components A and
B Separate
Foam Resins with 245 fa
Blowing Agents
Some foam blowing agents will froth at temperatures
above 90°F (33°C) when not under pressure, especially
if agitated. To reduce frothing, minimize preheating in a
circulation system.
Changing Materials
• When changing materials, flush the equipment mul-
tiple 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.
Spraying materials containing isocyanates creates
potentially harmful mists, vapors, and atomized partic-
ulates.
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.
Some materials may become self-igniting if applied
too thickly. Read material manufacturer’s warnings
and material MSDS.
NOTICE
To prevent cross-contamination of the equipment’s
wetted parts, never interchange component A (iso-
cyanate) and component B (resin) parts.