Moisture Sensitivity Of Isocyanates - Graco PR70 Instructions - Parts Manual

Warnings
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.
• The PR70 has exposed shafts, so extra precautions
must be taken when using ISO Materials. Make sure
that the shafts are wiped clean and lubricated if sit-
ting unused for any length of time, such as overnight
shutdowns. The lubricant creates a barrier between
the ISO and the atmosphere. Evaluate your system
and follow this procedure more often if necessary.
• 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.
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