Data Sheet

CRC Industries Deutschland GmbH
Inustrie-Serviceprodukte
Südring 9 D-76473 Iffezheim Deutschland
Tel (49) (0) 7229 303-0 Fax (49) (0) 7229 303-206
www.crcind.com
TECHNICAL DATA SHEET
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URETHAN 71
Ref. : 20750
1. GENERAL DESCRIPTION
Air drying one-component polyurethane-alkyd resin coating.
2. FEATURES
• URETHAN 71 is a transparent protective coating for printed circuit board, having excellent
insulating properties. The coating has an outstanding adhesion performance in the
temperature range from -40°C to +120°C. Due to the chemical cross linking reactions
happening after the drying stage, URETHAN 71 based coatings can also be used in humid
or aggressive environments.
3. APPLICATIONS
URETHAN 71 is a reliable coating for PCB’s, especially when used in hot/humid
environments.
Because of its aesthetics and good adhesion on many materials, URETHAN 71 can also be
used to provide decorative and transparent protection for every day metal articles. The
slightly yellow coloration enhances the aesthetics of non-ferro metal surfaces.
4. DIRECTIONS
 For small runs and service applications, the easiest way to use URETHAN 71 is from an
aerosol can. Spray the product from a distance of 20-30 cm on a dry, and degreased
surface. We do recommend Kontakt LR to remove greasy layers, dirt and flux remains
from PCB’s. After usage, purge the valve by spraying the can in an up-side-down position
until only propellant escapes.
 For serial production runs, bulk URETHAN 71 can be applied by brush, by dipping or by
spraying. If the mixture, as supplied, is too viscous for existing spraying equipment, a little
“Thinner for Urethan 71” (acetone) can be added. The exact mixing ratio must be
determined by trial.
 The product must be properly sealed when being stored. Because URETHAN 71 is
susceptible to cross-linking during drying, a coating once thickened can not be made
useable again by dilution.
 At ambient temperature, almost all solvents will be evaporated after 120 minutes. At this
stage the coating is sufficiently dry to allow further assemblies to be handled for
mounting. The chemical cross linking reactions take several days under ambient
conditions. However 90% cross-linking can be achieved after 24 hrs storage at 60°C.
 URETHAN 71 contains flammable solvents and hence all ignition sources should be
removed. Make sure there is good ventilation in the work place.
 Further information on safety can be obtained from the Material Safety Data Sheet.