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Polyurethane based » Polypast CL W » Polypast CL W


Polypast CL W

( Waterproofing / solvent free - 2 components PU for drinking water tanks)


The POLYPAST is a liquid-applied, solvent-free, hard-elastic, cold applied and cold curing, two component polyurethane membrane used for long-lasting waterproofing and protection.
Cures by reaction (cross linking) of the two components


  •     Low cost & easy application.
  •     When applied forms seamless membrane without joints or leak possibilities.
  •     Resistant to water and frost.
  •     Maintains its mechanical properties from -30oC up to +90oC temperature.
  •     Remains elastic at grate range of temperature.
  •     Full surface adherence.
  •     The waterproofed surface can be walked on.
  •     Appropriate & certified for safe use in potable (drinking) water tanks.


  •     Waterproofing of Drinking Water Tanks and Reservoirs.
  •     Waterproofing of Drinking Water Supply Channels.
  •     Waterproofing of Drinking Water Pipes.
  •     Odorless waterproofing of Wet Areas (under-tile) in Bathrooms, Swimming Pools, Kitchens, etc.

Used for waterproofing of surfaces in direct contact with potable (drinking) water.
Used for waterproofing of not well-ventilated, Wet Rooms and Wet Areas (bathrooms, kitchens, etc) applied under the tiles, when a odorless, solvent-free coating is required.
Technical Data:


1 Composition (Polyurethane Resin) + (Hardener)  
2 Mixing Ratio A : B  =  6 :1  (W/W)  
3 Density at 20°C:    A  =  1,13 gr / cm³  
B  =  1,24 gr / cm³
4 Solid Content 100% CALCULATED /  Inhouse Lab
5 Resistance to Water Pressure No Leak (1m water column, 24h) DIN EN 1928
6 Elongation at Break >100% ASTM D 412
7 Adhesion to concrete >2,0 N/mm 2 (concrete destruction) ASTM D 903
8 Hardness (Shore A Scale) 70 + 5 ASTM D 2240

UV accelerated ageing,

 in the presence of moisture
Passed - No significant changes EOTA TR-010
10 Hydrolysis (5% KOH, 7days cycle) No significant elastomeric change Inhouse Lab
11 Service Temperature -40oC to +90oC Inhouse Lab
12 Workability period (after mixing) 20 -30 minutes CALCULATED /  Inhouse Lab
13 Tack Free Time 6-8 hours Conditions: 20oC, 50% RH
14 Light Pedestrian Traffic Time 12-24 hours
15 Final Curing time (ponding test) 7 days
16 Chemical Properties Good resistance against acidic and alkali solutions (5%), detergents, seawater and oils.

Surface Preparation:

Careful surface preparation is essential for optimum finish and durability.
The surface needs to be clean, dry and sound, free of any contamination, which may harmfully affect the adhesion of the membrane. Maximum moisture content should not exceed 5%. Substrate compressive strength should be at least 25MPa, cohesive bond strength at least 1.5MPa. New concrete structures need to dry for at least 28 days. Old, loose coatings, dirt, fats, oils, organic substances and dust need to be removed by a grinding machine. Possible surface irregularities need to be smoothened. Any loose surface pieces and grinding dust need to be thoroughly removed.
WARNING: Do not wash surface with water before application !
Repair of cracks and joints:
The careful sealing of existing cracks and joints before the application is extremely important for long lasting waterproofing results.
•    Clean concrete cracks and hairline cracks, of dust, residue or other contamination. Prime locally with PU primer HYDROMER and allow 2-3 hours to dry. Fill all prepared cracks with PU mastic / HYDROSEAL sealant. Then apply a layer of POLYPAST , 200mm wide centered over all cracks and while wet, cover with a correct cut stripe of the FABRIC. Press it to soak. Then saturate the FABRIC with enough POLYPAST, until it is fully covered. Allow 12 hours to cure.
•    Clean concrete expansion joints and control joints of dust, residue or other contamination. Widen and deepen joints (cut open) if necessary. The prepared movement joint should have a depth of 10-15 mm. The width: depth ratio of the movement joint should be at a rate of approx. 2:1.
Apply some PU mastic / HYDROSEAL joint-sealant on the bottom of the joint only. Then with a brush, apply a stripe layer of POLYPAST, 200mm wide centered over and inside the joint. Place the FABRIC over the wet coating and with a suitable tool, press it deep inside the joint, until it is soaked and the joint is fully covered from the inside. Then fully saturate the FABRIC with enough POLYPAST. Then place a polyethylene cord of the correct dimensions inside the joint and press it deep inside onto the saturated FABRIC. Fill the remaining free space of the joint with PU mastic / HYDROSEAL sealant. Do not cover. Allow 12 hours to cure.
Prime surfaces, like concrete, cement screed, metal, and ceramic tiles with enough PU primer HYDROMER (min. 250 – 300 gr/m2). Allow 12 hours to cure.
Stir POLYPAST Component A well before using. Then add the POLYPAST Component B at the stipulated mixing  ratio. POLYPAST Component A and Component B should be mixed by low speed mechanical stirrer, for about
3-5 min.

ATTENTION:  The mixing of the components has to be effected very thoroughly, especially
on the walls and bottom of the pail until the mixture becomes fully homogeneous.

Waterproofing membrane:
Poor the entire POLYPAST A+B mixture, onto the primed and prepared surface and lay it out by roller or brush, until all surface is covered.
Please ensure consumption within the pot life of the product (~30min)! Please do not leave the mixed POLYPAST A+B coating in the pail for long, because the exothermic reaction accelerates the curing and will shorten the pot-life. Directly after mixing poor the mixture on the surface on in smaller pails to minimise the exothermic reaction.

Reinforce with FABRIC at problematic areas, like wall-floor connections, pipe-outlets, waterspouts (siphon), etc. In order to do that, apply on the still wet POLYPAST a correct cut piece of FABRIC, press it to soak, and saturate again with enough POLYPAST. For detailed application instructions with the POLYPAST, contact our R+D department.

After 12-18 hours - but not later than 48 hours –apply another layer of the POLYPAST, by using roller or brush. For demanding applications apply a third layer.
RECOMMENDATION: We recommend reinforcement of the entire surface, with FABRIC. Use 5-10cm stripe overlapping.
RECOMMENDATION: For best results, the temperature during application and cure should be between 5°C and 30°C.  Low temperatures retard cure while high temperature speed up curing.  High humidity may affect the final finish.
WARNING: The POLYPAST is slippery when wet. In order to avoid slipperiness during wet days, sprinkle suitable aggregates onto the still wet coating to create an anti-slip surface. Please contact our R+D Dept. for more details.
1,2 - 1,5 kg/m2 applied in three layers.
This coverage is based on practical application by roller onto a smooth surface in optimum conditions. Factors like surface porosity, temperature, humidity, application method and finish required can alter consumption.

Packaging - Colors:
POLYPAST A+B is supplied in 6+1 kg pails. Pails should be stored in dry and cool rooms for up to 9 months. Protect the material against moisture and direct sunlight. Storage temperature: 5°-30°C.  Products should remain in their original, unopened containers, bearing the manufacturers name, product designation, batch number and application precaution labels.
The POLYPAST is supplied in off-white. Other RAL colors may be supplied on demand.

Safety measures:
POLYPAST contains isocyanates. See information supplied by the manufacturer. Please study the
(M.S.D.S.) (A)  (M.S.D.S.) (B) Safety Data sheet.      -    P R O F E S S I O N A L    USE ONLY.




Note for users: The information contained in the present sheet are based on our own knowledge on the date of the last version. Users must verify the suitability and thoroughness of provided information according to each specific use of the product. This document must not be regarded as a guarantee on any specific product property. The use of this product is not subject to our direct control; therefore, users must, under their own responsibility, comply with the current health and safety laws and regulations. The producer is relieved from any liability arising from improper uses.

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