One Component Adhesive Sealant (Sikaflex®-221) |
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| Description |
| Sikaflex®-221 is a high-quality
multi-purpose non-sag one-part
polyurethane sealant that cures on
exposure to atmospheric moisture
to form a durable elastomer. Tried
and tested in service for many
years, Sikaflex®-221 is manufactured
in accordance with the ISO
9001/14001 quality assurance
system. |
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| Areas of Application |
| Sikaflex®-221 bonds well to a wide
variety of substrates and is suitable
for making permanent elastic
seals of high adhesive strength.
Suitable substrate materials are
timber, metals, metal primers and
paint coatings (two-part systems),
ceramic materials and plastics.
Seek manufacturer’s advice before using on transparent and pigmented
materials that are prone to
stress cracking. |
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| Product benefits: |
• one-part formulation
• elastic
• low odour
• resistant to ageing and
weathering
• non-corrosive
• can be overpainted
• can be sanded
• bonds well to a wide variety ofsubstrates
• approved for contact with foodstuff |
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| Cure Mechanism |
Sikaflex®-221 cures by reaction
with atmospheric moisture. At low
temperatures the water content of
the air is generally lower and the
curing reaction proceeds somewhat
slower (see diagram). |
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| Chemical Resistance |
Sikaflex®-221 is resistant to fresh
water, seawater, limewater, sewage
effluent, diluted 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 will be given
on request. |
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| Method of Application |
| Surface preparation: The faces of
the joint must be clean, dry and
free from all traces of grease, oil
and dust. As a rule, the substrates
must be prepared in accordance
with the instructions given in the
current Sika Primer Chart. |
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| Application |
For cartridges: pierce
the cartridge membrane and peel
back completely. For unipacs:
place in the application gun and
snip off the closure clip.
Cut off the tip of the nozzle to suit
joint width and gun the sealant into
the joint with a suitable handoperated
or compressed-air gun,
taking care to avoid air entrapment.
Once opened, packs should
be used up within a relatively short
space of time.
Do not apply at temperatures below
5°C or above 35°C. The optimum
temperature for substrate
and sealant is between 15°C and
25°C. For advice on bulk dispensing
from hobbocks or drums,
please contact the Systems Engineering
Department at Sika Industry.
For information and advice on the
safe handling, storage and disposal
of chemical products, users
should refer to the current Safety
Data Sheet containing physical,
ecological, toxicological and other
safety-related data.
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| Tooling and finishing: |
| Tooling and
finishing must be carried out within
the tack-free time of the sealant.
We recommend the use of Sika®
Tooling Agent N. Other finishing
agents or lubricants must be tested
for suitability / compatibility. |
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| Overpainting: |
Sikaflex®-221 can be
overpainted when tack-free. The
paint must be tested for compatibility
by carrying out preliminary
trials. Baked enamels should not
be applied to Sikaflex®-221 until
the sealant has attained full cure. It
should be understood that the
hardness and film thickness of the
paint may impair the elasticity of
the sealant and lead to cracking of
the paint film. |
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| Removal: |
Uncured Sikaflex®-221 may be
removed from tools and equipment
with Sika® Remover-208. 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! |
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| Further information: |
Copies of the following publications
are available on request:
• Sika Primer Chart
• Safety Data Sheet |
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| Note: |
The information, and, in particular, the recommendations
relating to the application
and end-use of Sika products, are given in
good faith based on Sika's current know ledge
and experience of the products when
properly stored, handled and applied under
normal conditions. In practice, the differences
in materials, substrates and actual
site conditions are such that no warranty in
respect of merchantability or of fitness for a
particular purpose, nor any liability arising
out of any legal relationship whatsoever,
can be inferred either from this information,
or from any written recommendations, or
from any other advice offered. The proprietary
rights of third parties must be observed.
All orders are accepted subject to
our current terms of sale and delivery. Users
should always refer to the most recent
issue of the Technical Data Sheet for the
product concerned, copies of which will be
supplied on request. |
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