MasterSeal M 790 waterproofing and protecting concrete | MCT CHEMICALS | MASTER BUILDER SOLUTIONS

FIELD OF APPLICATION
MasterSeal M 790 is ideal for waterproofing applications requiring high chemical resistance. It is suitable for:

• Wastewater treatment plants (both inflow and outflow areas)
• Sewage effluent pipelines
• Biogas plants
• Secondary containment areas

MasterSeal M 790 can be applied to:

• Horizontal and vertical surfaces
• Internal and external areas, including those exposed to rubber wheel traffic
• Concrete, cementitious mortar, or steel surfaces
• Reinforced concrete to protect against carbonation, chloride-induced corrosion, and chemical damage, particularly in secondary containment in chemical and petrochemical industries.

Consult a Master Builders Solutions representative for other applications not listed.

FEATURES AND BENEFITS

• Easily applied by roller or trowel
• Forms a continuous, monolithic membrane with no laps, welds, or seams
• Outstanding chemical resistance, including to high concentrations of biogenic sulfuric acid
• Waterproof and resistant to standing water
• Fully bonded to the substrate with the appropriate primer
• Moisture tolerant: can be applied to substrates with high residual humidity
• Protects concrete from rebar corrosion due to high resistance to CO₂ diffusion
• High resistance to tear, abrasion, and impact, suitable for areas exposed to mechanical wear
• Tough, flexible, and crack-bridging
• Durable with reduced cracking due to embrittlement
• Thermoset: maintains integrity at high temperatures
• Excellent adhesion to various substrates (concrete, steel)
• Weatherproof: resistant to thundershowers, freeze-thaw cycles, and can be applied outdoors without a topcoat
• Solvent-free formulation
• Can be spray-applied using selected 2-component spray machines (contact technical service for details)

APPROVALS AND CERTIFICATES

• Proven long-term resistance to biogenic sulfuric acid corrosion (Fraunhofer Institute)
• CE Certification according to EN 1504-2
• Chemical resistance per EN 13529
• Bond strength and blistering resistance under reverse moisture exposure (DAfStb Repair Guideline)
• DIBt approval for use in concrete in biogas facilities, tanks, bunker silos, and containment areas for liquid manure and silage (JGS).

APPLICATION METHOD

(a) Surface Preparation
Ensure substrates (new and old) are structurally sound, dry, free from laitance, loose particles, oil, grease, rubber marks, paint stains, and other contaminants that may affect adhesion.
For concrete, prepare the surface with shot blasting, high-pressure water jetting, or another suitable mechanical method. Concrete and cementitious substrates should have a minimum pull-off strength of 1.5 N/mm² (lowest single value 1.0 N/mm²).
Substrate temperatures should range from +5°C to +35°C, with the temperature of contact surfaces at least 3°C above the ambient dew point temperature.

(b) Primer Coat
A primer coat enhances adhesion and helps prevent pinholes or bubbles in the final layer. The recommended primer for MasterSeal M 790 is MasterSeal P 770. The substrate should be visibly dry with no restrictions on residual humidity. The temperature of contact surfaces should be at least 3°C above the dew point. Apply MasterSeal P 770 by roller in a single layer, with an approximate consumption of 0.25-0.4 kg/m². Wait at least 5 hours (at +20°C) before applying MasterSeal M 790. It is recommended to overcoat within 48 hours of primer application. If this time is exceeded, consult your Master Builders Solutions representative.

(c) Mixing
MasterSeal M 790 is provided in pre-measured kits with the correct mixing ratio. Combine all of Part A with Part B and mix with a mechanical drill and paddle at low speed (max. 400 rpm) for 90 seconds. Ensure thorough mixing and avoid air bubbles. Do not mix partial packs or by hand. Unused mixed material can generate heat, so always use the full amount.

(d) Application
MasterSeal M 790 can be applied with a brush or roller. It is recommended to apply at least two layers. The minimum wait time between coats is 8 hours (overnight) at +20°C for both ambient and substrate temperatures. We recommend applying the second coat within 48 hours; otherwise, contact your Master Builders Solutions representative.

FINISHING AND CLEANING
Clean tools with solvent-based cleaner while still wet.