Product Data Sheet Show all documents

Sikagard® M 790

(former MasterSeal® M 790)

2-component highly chemical resistant, crack-bridging membrane based on Xolutec® for protection of concrete structures in harsh conditions

Sikagard® M 790 is a two-component crack-bridging membrane based on Xolutec® - Technology providing high chemical and mechanical resistance. Xolutec is an innovative and smart way of combining complementary chemistries. When the material is mixed on site a cross linked interpenetrating network (XPN) is formed enhancing the overall material properties. By controlling the cross-linking density, the properties of Xolutec can be adjusted depending on the product performance required, e.g. this allows the formulation of materials with varying degrees of toughness and flexibility. Xolutec is very low in volatile organic components (VOC), is quick and easy to apply with both spray and hand application depending on requirements. It cures rapidly even at low temperature, reducing application time thus enabling fast return to service and minimizing downtime. This technology is not sensitive to moisture and tolerates a wide variety of different site conditions, greatly expanding the application window and reducing the potential for delays and failures. Long maintenance cycles and lower life cycle costs significantly reduce total cost of ownership.

  • Easy hand application by roller or trowel
  • Continuous membrane: monolithic – no laps, welds or seams
  • Excellent chemical resistance – including high concentrations of biogenic sulphuric acid.
  • Waterproof and resistant to standing water
  • Fully bonded to substrate: can be applied to a wide range of substrates with the appropriate primer.
  • Moisture tolerant: can be applied on substrates with high residual humidity.
  • High resistance to carbon dioxide diffusion: Protects concrete from rebar corrosion.
  • High tear, abrasion and impact resistance: Withstands traffic and use in areas exposed to mechanical damages.
  • Tough - but flexible and crack bridging
  • Long-term durability and protection
  • Thermoset: does not soften at high temperatures.
  • Weatherproof: proven thundershower and freeze / thaw resistance, can be applied outdoors without additional top coating.
  • Does not contain solvents
  • Can be spray-applied with selected 2-component spray machines (please contact our technical service for details)
Product Data Sheet Show all documents

Usage

Sikagard® M 790 is used in all protection applications where a high level of chemical resistance is required. This includes:
  • Waste water treatment plants both in the inflow and outflow areas.
  • Sewage effluent pipelines.
  • Biogas plants.
  • Secondary containment.
  Sikagard® M 790 can be applied on:
  • Horizontal and vertical substrates.
  • Internal and external areas, also with rubber wheel traffic.
  • Concrete, cementitious mortar or steel substrates.
  • Reinforced concrete to protect it against carbonation or chloride induced corrosion and for protection against chemical attack in secondary containment bunds in chemical and petrochemical industries.
Contact your local Sika representative for any other applications not listed here.

Advantages

  • Easy hand application by roller or trowel
  • Continuous membrane: monolithic – no laps, welds or seams
  • Excellent chemical resistance – including high concentrations of biogenic sulphuric acid.
  • Waterproof and resistant to standing water
  • Fully bonded to substrate: can be applied to a wide range of substrates with the appropriate primer.
  • Moisture tolerant: can be applied on substrates with high residual humidity.
  • High resistance to carbon dioxide diffusion: Protects concrete from rebar corrosion.
  • High tear, abrasion and impact resistance: Withstands traffic and use in areas exposed to mechanical damages.
  • Tough - but flexible and crack bridging
  • Long-term durability and protection
  • Thermoset: does not soften at high temperatures.
  • Weatherproof: proven thundershower and freeze / thaw resistance, can be applied outdoors without additional top coating.
  • Does not contain solvents
  • Can be spray-applied with selected 2-component spray machines (please contact our technical service for details)

Packaging

Sikagard® M 790 is available in

  • 5 kg Kits consisting of 1.5 kg Part A and 3.5 kg Part B

  • 10 kg Kits consisting of 3 kg Part A and 7 kg Part B

  • 30 kg Kits consisting of 9 kg Part A and 21 kg Part B

Colour

Part A: grey or red liquid

Part B: yellowish liquid

Product Details

Sustainability / Certifications / Approvals

CERTIFICATES AND TEST REPORTS

  • CE Certification according to EN 1504-2

  • Long-term resistance to biogenic sulfuric acid corrosion resistance (Fraunhofer Institute)

  • Chemical Resistance according to EN 13529

  • Bond Strength and blistering if exposed to reverse moisture according to DAfStb Repair Guideline

  • DIBt-Approval for use in concrete in biogas facilities, tanks, bunker silos and for containment areas in storage and filling of liquid manure and silage (JGS).
Product Information

Shelf life

12 months in unopened pails if stored under below mentioned storage conditions.

Storage conditions

Sikagard® M 790 must be stored in unopened, original containers under dry conditions at temperatures between 10 - 25° C preferably. Protect from frost and no permanent storage over +30 °C.

Density

Part A

approx. 1.27 g/cm³

Part B

approx. 1.15 g/cm³

Mixed

approx. 1.2 g/cm³

Viscosity

Mixed Product

approx. 2800 mPas

(EN ISO 3219)
System information

System structure

Sikagard®-7000 CR consists of two components: the primer Sikagard® P 770 and the membrane Sikagard® M 790, both based on our innovative Xolutec® technology. The two colours of Sikagard® M 790 – red and grey – allow safe application even in environments with poor visibility.
Technical Information

Shore D Hardness

After 7 days

80

Abrasion resistance

Taber test (mass loss)

194 mg

BCA test (thickness loss)

 < 10 µm (= class AR 0,5)

Dynamic friction (test for rubber wheel traffic) “Stuttgarter Gerät”

Assessment

20,000 cycles dry

no abrasion of material

20.000 cycles wet

no abrasion of material

Resistance to impact

24.5 Nm (class III)

Tensile strength

> 20 N/mm²

Crack bridging ability

Static Crack bridging

At +23 °C

> 0.5 mm (class A3)

At +70 °C (dry curing)

> 0.25 mm (class A2)

At -10 °C

> 0.25 mm (class A2)

Dynamic Crack bridging

At +23 °C

class B3.1

At -10 °C

class B2

Tensile adhesion strength

dry concrete after 28d

2.9 N/mm²

wet concrete after 28d

2.2 N/mm²

steel (without Primer) after 7d

≥ 7.0 N/mm²

(EN 1542) (EN 13578)

(EN 12188)

Temperature resistance

Service temperature (dry)

- 20 to +80 ºC

Service temperature (wet)

up to +60 °C

Capillary absorption

0.0005 kg/m2·h0,5

(EN 1062-3)

Water penetration under pressure

Resistance to positive water pressure

5 bar

Water penetration under negative pressure

Resistance to negative water pressure

2.5 bar

(UNI 8298-8)

Permeability to water vapour

Class III (SD = 126 m)

(EN ISO 7783)

Permeability to carbon dioxide

SD = 206 m

EN 1062-6)

Chemical resistance

Please refer to the detailed Chemical Resistance information (available on request).

Water resistance

Resistance to osmotic pressure (with Sikagard P 770 and Sikagard-385 Epocem as primers)

No adhesion loss and no bubble formation

Behaviour after artificial weathering

After 2000 h

no blistering, cracking or flaking; colour change

Freeze thaw de-icing salt resistance

Adhesion to concrete after cycling with de-icing salt immersion & thunder shower cycling

2.7 N/mm²

(EN 13687-1 & EN 13687-2)

Reaction to fire

Class E

(EN 13501-1)

Application

Application Information

Mixing ratio

Mixing ratio Part A : Part B (by weight)

1 : 2.33

Mixing ratio Part A : Part B (by volume)

1 : 2.58

Please note that Part B is the bigger part of the mix!

 

Ambient air temperature

+5 to +35 °C

Relative air humidity

Not restricted, but no condensation of water on the surface.

Dew point

The temperature of the contact surfaces must be at least 3 °C above the ambient dew point temperature.

Substrate temperature

+5 to +35 °C

Substrate moisture content

Not restricted, but surface must be visibly dry.

Pot Life

at +10 °C

approx. 25 min

at +20 °C

approx. 20 min

at +30 °C

approx. 15 min

Waiting time to overcoating

at +5 °C

approx. 24 hours

at +20 °C

approx. 8 hours

at +30 °C

approx. 4 hours

Applied product ready for use

Exposure to water pressure at +20 °C after

24 hours

Fully cured at +20 °C after

7 days
Consumption

Consumption

The consumption of Sikagard® M 790 hand-applied is approximately 0.4 kg/m² per coat. A minimum of two coats is required, depending on the condition and porosity of the substrate and requested film thickness. A two-coat application with a total consumption of approximately 0.8 kg/m² will provide a dry film thickness of approx. 0.7 – 0.8 mm. In high chemically demanding environments (e.g. industrial waste water treatment plants) and/or in harsh, abrasive conditions, a dry film thickness of 1.0 - 1.1 mm is recommended. Therefore, a minimum consumption of 1.0 - 1.2 kg /m² in two or three layers must be applied.

With the specific spraying equipment, the application of up to 1 mm thickness can be completed in one coat.

These consumptions are theoretical and can vary according to the absorption and roughness of the substrate. It is essential to carry out representative trials on site to evaluate the exact consumption.
Application steps

SUBSTRATE PREPARATION

Sikagard® M 790 must be applied to primed substrates.

A primer coat will improve the adhesion and prevent the appearance of pinholes or bubbles in the hardened coating. The recommended primer for Sikagard® M 790 is Sikagard® P 770.

Priming instructions: The prepared substrate should be visibly dry - there is no limit to residual humidity. The substrate temperature must be minimum +5 °C and maximum +35 °C. The temperature of the contact surfaces must be at least 3 °C above the ambient dew point temperature.

Sikagard® P 770 can be applied by roller in one layer and its consumption is approx. 0.25 - 0.4 kg/m². Wait for at least 5 hours (at + 20° C) before applying Sikagard® M 790. We recommend overcoating the primer within the next 48 hours of its application. If this time is exceeded, please contact your local technical Sika representative. 

MIXING

Sikagard® M 790 is supplied in working kits which are pre-packaged in the exact mixing ratio.

Open the two Parts of the product and briefly mix the single components with a mechanical drill and paddle at low speed (max. 400 rpm) in order to obtain a uniform consistency.

Then pour the entire content of Part A into the container of Part B and mix with a mechanical drill and paddle at low speed (max. 400 rpm) for 90 seconds. Scrape the sides and the bottom of the container several times to ensure complete mixing. Keep the mixer blades submerged in the coating to avoid introducing air bubbles.

Do not mix part packs and do not mix by hand!

Attention: unused remains of mixed material can lead to a strong heat development in the pail. Always use up all mixed material completely.

APPLICATION

Sikagard® M 790 can be manually applied by brush or roller. It is always recommended to complete the application in a minimum of two layers.

For spray application of Sikagard® M 790 please refer to our General Method Statement for Sikagard®-7000 CR system.

 

At low temperatures, the chemical reactions are slowed down; this lengthens the pot life, open time and curing times. High temperatures speed up the chemical reactions thus the pot life, open time and curing times are shortened accordingly. To fully cure, the material, substrate and application temperature should not fall below the minimum. The temperature of the contact surfaces must be at least 3 °C above the ambient dew point temperature.

Minimum waiting time before application of second coat is 8 hours (overnight) at +20 °C ambient and substrate temperature. We recommend completing the application of the subsequent coat within 48 hours. If this time is exceeded, please contact our Technical Service.

CLEANING OF EQUIPMENT

Tools can be cleaned with solvent-based cleaner while still wet. Once cured, the material can only be removed mechanically.

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