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Important Two-Component Material Information
10 309572ZAF
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 crystal-
lization 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 con-
taminated from the other side.
• Always lubricate threaded parts with ISO pump oil
or grease when reassembling.
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.