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Sikaflex
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Product Data Sheet
Version 2/8/08
Sikaflex
®
-252
Elastic Adhesive
Technical Product Data (typical values)
Chemical base
1-C polyurethane
Color
White, Black
Cure mechanism
Moisture Curing
Density (uncured)
9.7-10.2 lb/gal (depends on
color)
VOC (EPA method 24)
0.51 lb/gal (61 g/l)
Non-sag properties
Very Good
Application temperature product
50 - 95°F (10 35°C)
Tack free time
1

40 min
Curing speed
(see diagram 1)
Shrinkage
6%
Shore A-hardness (ASTM D 2240)
55
Tensile strength (ASTM D 412)
580 psi
Elongation at break (ASTM D 412)
>300%
Tear propagation resistance (ASTM D 624)
51 pli
Tensile lap-shear strength (ASTM D 1002)
360 psi
Volume resistivity (ASTM D 257-99)
5 x 10
9
Wcm
Service temperature permanent
Short term 4hours
1hour
-40 - 194°F (-40 - 90°C)
266°F (130°C)
302°F (150°C)
Shelf life (storage below 80°F (27°C)) Cartridges & Unipac
Drums & Pails
9 months
6 months
1)
73°F (23°C) / 50% r.h.

Description
Sikaflex
®
-252 is a 1-component,
moisture
cured,
polyurethane
adhesive
with
extremely
high
thixotropy
and
high
strength.
Sikaflex
®
-252 is particularly suited to
bonding
applications
in
the
manufacture of trucks, trailers and
equipment.
Sikaflex
®
-252
is
manufactured under strict quality
control
to
the
highest
Sika
standards.

Sikaflex
®
-252
is
manufactured in accordance with
ISO 9001 / 14001 quality assurance
system and the Responsible Care
Program.

Product Benefits
- Bonds and seals at the same time.
- One part formulation.
- Replaces rivets and mechanical
fasteners.
- Very high thixotropy for good gap
filling properties.
- Adhesion to a wide range of
substrates.
- Short tack free and curing time.
- Non-staining curing process.
- Initial load bearing capacity.
- Sandable and paintable.
- Increases torsional stiffness of
final assembly.
- Shock/impact resistant. Vibration
and sound damping.
- Excellent weather and water
resistance.
- USDA approved for incidental food
contact.

Areas of Application
- Seek manufacturer's advice before
using on plastics that are prone to
stress cracking.
- Bonding of floors (plywood,
blandex, wood, metal) to subfloor
or metallic frame.
- Bonding of all exterior or interior
panels, walls, sheets to corners or
tubular frames.
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Further information available at:
www.sikaindustry.com











Sika Corporation
Industry Division
30800 Stephenson Highway
Madison Heights, MI 48071
USA
Tel. 248 577 0020
Fax 248 577 0810
- Bonding of FRP roofs (vans,
cabins).
- Bonding of trim, molding and all
kinds of styling elements.
- Sealing, especially for large
dimension joints.
- This product is suitable for
experienced professional users
only.
- Tests with actual substrates and
conditions have to be performed to
ensure adhesion and material
compatibility.

Cure Mechanism
Sikaflex
®
-252 cures by reaction
with atmospheric moisture. At low
temperature the water content of
the air is generally lower and the
curing reaction proceeds slower
(see diagram).

Time (days)

0

0

2

4

6

23°C / 50% r.h

10

8

12

10°C / 50% r.h

4

T
h
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k
n
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s

o
f

c
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e

(
m
m
)


Diagram 1: Curing speed Sikaflex
®
-252
Chemical Resistance
Sikaflex
®
-252 is resistant to fresh
water, seawater, limewater, sewage
effluent, dilute acids and caustic
solutions; temporarily resistant to
fuels, mineral oils, vegetable and
animal fats and oils; not resistant to
organic acids, alcohol, concentrated
mineral acids and caustic solutions
or solvents. The above information
is offered for general guidance only.
Advice on specific applications is
available from the Technical Service
Department of Sika Industry at 888-
832-7452. The above information is
offered for general guidance only.
Method of Application
Surface preparation
Surfaces must be clean, dry, free of
water, oil, grease or rust and of
sound quality. Remove all loose
particles or residues with a jet of
compressed air, sandpaper, or hard
brush. Clean surface with a solvent,
such as acetone, which can be
tolerated by the substrate. Pretest
substrates for adhesion. Cleaners
and/or primers may be required to
achieve optimal adhesion. Please
refer to the Sika Primer Chart for
specific
application
information.
Advice on specific applications and
primer chart is available from the
Technical Service Department of
Sika Industry at 888-832-7452.

Application
Cartridges:
Pierce
cartridge
membrane. Affix nozzle.
Unipacs: Place unipac in the
application gun and snip off the
closure clip. Cut off the tip of the
nozzle to joint size. To ensure
uniform thickness of adhesive when
compressed,
we
recommend
applying the adhesive in the form of
a triangular bead (see illustration).
Use a hand or powered caulking
gun. If Sikaflex
®
-252 is used as an
adhesive,
assemble
within
15
minutes. Make sure surfaces are
frost free. Do not apply at
temperatures below 50°F (10°C) or
above 95°F (35°). The optimum
temperature
for
substrate
and
adhesive is between 60°F (15°C)
and 77°F (25°C). For advice on
selecting and setting up a suitable
pump system, as well as on the
techniques
of
pump
operated
application, please contact the
System Engineering Department of
Sika Industry at 248-577-0020.
Advice on specific applications is
available from the Technical Service
Department of Sika Industry at 888-
832-7452.

b
b
h
2h

Figure 1:
Recommended bead
configuration
Tooling and finishing
Tooling and finishing must be
carried out within the tack free time
of the adhesive. We recommend the
use of Sika
®
-Slick Cutout Lubricant
and Tooling Agent. Other finishing
agents or lubricants must be tested
for suitability / compatibility. Advice
on specific applications is available
from
the
Technical
Service
Department of Sika Industry at 888-
832-7452.

Removal
Uncured Sikaflex
®
-252 may be
removed from tools and equipment
with Sika
®
Remover-208 or another
suitable
solvent.
Strictly
follow
solvent manufacturer's warnings and
instructions for use. Once cured,
the material can only be removed
mechanically. Hands and exposed
skin should be washed immediately
using a suitable industrial hand
cleanser and water. Do not use
solvents on skin!
Overpainting
Sikaflex
®
-252 can be overpainted
when tack free. The paint and paint
process compatibility must be tested
before use. Sikaflex
®
-252 should
not
be
exposed
to
baking
temperatures until it has attained full
cure. It should be understood that
the hardness and film thickness of
the paint may impair the elasticity of
the adhesive and lead to cracking of
the paint film with time.
Limitations
- Since system is moisture-cured,
permit sufficient exposure to air.
- Do not apply over silicones or in
the presence of curing silicones.
- Avoid contact with alcohol, and
alcohol containing solvents, during
cure.
- For best results, use opened
cartridges the same day.

WARNING:
IRRITANT, SENSITIZER. Contains
Polyisocyanate
Prepolymer
(Mixture), Xylene (CAS 1330-20-7).
Causes eye irritation. May cause
skin/respiratory
irritation.

May
cause
skin
and/or
respiratory
sensitization
after
prolonged
contact.
May
be
harmful
if
swallowed. Reports have associated
repeated and prolonged exposure to
some of the chemicals in this
product with permanent brain, liver,
kidney
and
nervous
system
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Further information available at: