Product Data Sheet
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Sikagard®-678 WMY

Acrylate based water dispersed protective coating for concrete

Sikagard®-678 WMY is a single component, low VOC elastomeric, water dispersed protective coating system based on the latest technology in acrylate dispersion. When fully cured, Sikagard®-678 WMY forms a flexible finishing film which is slightly breathable but is impermeable to water and atmospheric gases.

  • Good water vapour permeability
  • Acrylate based – Alkaline resistant
  • High diffusion-resistance to CO2, good carbonation barrier
  • Excellent resistance to weathering, UV and dirt resistant
  • Resistance to temperature changes and de-icing salts
  • Excellent resistance against chalking
  • Open to vapour diffusion
  • Greatly reduced water absorption
  • Easy to apply by roller or spraying
  • Ecologically and environmentally harmless
  • Crack-bridging protection 
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Product Data Sheet
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Usage

For protection and embellishment of facades and fair-face concrete without obscuring the characteristic surface texture of the concrete:
  • Concrete protection system against aggressive pollutants
  • Surface protection for exterior areas (No traffic)
  • Architectural colour design on fair-face concrete structures
  • Suitable for use in areas sprayed with de-icing salts
 

Advantages

  • Good water vapour permeability
  • Acrylate based – Alkaline resistant
  • High diffusion-resistance to CO2, good carbonation barrier
  • Excellent resistance to weathering, UV and dirt resistant
  • Resistance to temperature changes and de-icing salts
  • Excellent resistance against chalking
  • Open to vapour diffusion
  • Greatly reduced water absorption
  • Easy to apply by roller or spraying
  • Ecologically and environmentally harmless
  • Crack-bridging protection 

Packaging

20 kg pail

Colour

Standard colours include:
Pebble Grey (~RAL 7032), Light Grey (~RAL 7035), Silver Grey (~RAL 7001) and White (~RAL 9010)
Non-standard colours are also available upon request.

Product Details

Product Information

Composition

Acrylate Based water dispersed

Shelf Life

12 months from the date of production

Storage Conditions

Store in original unopened packaging in a cool, dry place at temperatures between +5 °C to +35 °C. Protect from direct sunlight.
Technical Information

Tensile Adhesion Strength

~4.0 N/mm²

(EN 1542:1999)

Crack Bridging Ability

Static

Class A4 width of bridged crack > 1.25 mm

Dynamic

Class A4 width of bridged crack > 1.25 mm

Thermal Compatibility

Thunder Shower Cycling / Thermal Shock

After thermal cycling:

  • No bubbles, cracks and delamination
  • Adhesion strength > 1.5 MPa

(BS EN 13687-2 :2002 & BS EN 1542:1999)

Reaction to Fire

Class A1

(BS EN ISO 1182: 2020 & BS EN13501-1:2018)

Behaviour after Artificial Weathering

After 2 000 h of artificial weathering

Elevated Temperature

No defect (satisfactory)

UV radiation and humidity 

No defect (satisfactory)

Permeability to Water Vapour

µ: ~7 000

Sd: ~1.33 m

Class 1 (Sd < 5 m)

(EN ISO 7783:2011)

Capillary Absorption

w: ~0.04 kg/(m²h½)

(EN 1062-3:2008)

Permeability to Carbon Dioxide

µ: ~15 500

Sd: ~265 m

(EN 1062-6:2002)

Application

Application Information

Ambient Air Temperature

+8 °C min. / +35 °C max.

Relative Air Humidity

80 % max.

Dew Point

Observe dew point

Substrate Temperature

+8 °C min. / +35 °C max.
At rising temperatures, do not apply to concrete substrates without pore sealer.

Waiting Time / Overcoating

4–6 hours at 30 °C, 80 % r.h.

Drying Time

Touch dry

~2.5 h at 30 °C. 80 % r.h.
Consumption

Consumption

Standard system based on requirement for a minimum total DFT of 150 µm as follows:

Primer coat

1x Sikagard®-678 WMY Primer at 0.10–0.15 kg/m²/coat

Top coat

2x Sikagard®-678 WMY at 0.20–0.30 kg/m²/coat

Note: Depending on substrate porosity.
Application steps

APPLICATION

Sikagard®-678 WMY is supplied ready to use. However, before applying, the material must be thoroughly stirred with a mechanical stirrer. Sikagard®-678 WMY can be applied by roller (preferably with a short piled lamb skin roller) or airless spray equipment with a pressure of 180 bar, nozzle with opening diameter of 0.38–0.66 mm and a spraying angle of 50–60°. Use as it is and do not dilute with more than 5 % of water, by volume. Application must not proceed during rain or high air humidity. Freshly applied layers must be protected from dew, fog, rain and frost. For cracks larger than 0.2 mm, other special repair material is required prior to application of Sikagard®-678 WMY. Please contact our Technical Service Department for more information.

 

CLEANING OF TOOLS

Clean all tools and application equipment with water immediately after use. Hardened or cured material can only be mechanically removed.

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