Nitomortar 903: Solvent-Free Epoxy Resin Binder System

Product Overview

Nitomortar 903 is a solvent-free, general-purpose, two-component epoxy binder and priming system manufactured by Fosroc International Limited. It serves as a versatile epoxy resin foundation that can be mixed with selected fillers and aggregates to produce epoxy mortars of various consistencies for multiple construction applications.

Key Technical Specifications

Composition & Properties

Nitomortar 903 is a low-viscosity epoxy resin system with the following technical characteristics:

Mechanical Strength

Nitomortar 903 demonstrates exceptional compressive strength capabilities:

• Up to 90 MPa compressive strength depending on mix consistency
• Strength varies based on filler ratios and application method
• Can achieve 76 MPa at 7 days with fluid paste consistency (1:2 ratio)
• Can achieve 45 MPa at 7 days with dry mortar consistency (1:5 ratio)

Chemical Resistance

Nitomortar 903 exhibits excellent resistance to a wide range of acids, alkalis, and industrial chemicals, including:

• Citric Acid 10% - Excellent
• Tartaric Acid 10% - Excellent
• Hydrochloric Acid 25% - Excellent
• Sodium Hydroxide 50% - Excellent
• Sulphuric Acid 50% - Very Good
• Diesel Fuel/Petrol - Very Good
• Sugar Solutions - Very Good
• Lactic Acid - Very Good
• Phosphoric Acid 50% - Very Good

Primary Uses & Applications

Nitomortar 903 serves multiple functions in construction and repair applications:

As an Epoxy Binder

• Combined with Nitomortar F4 Fillers in varying proportions to create epoxy mortars and screeds of different consistencies
• Produces fluid paste, stiff paste, trowellable, and dry mortar consistencies depending on filler ratios

As a Scratch Coat

• Used to smooth rough or uneven concrete surfaces
• Prepares substrates for subsequent coating applications such as Nitoflor PU200 or Nitoflor FC150 HP/SL flooring systems

As a Priming System

• Functions as a primer for porous concrete substrates
• Serves as an alternative to Nitoflor N clear binder for substrate preparation
• Recommended as a substrate primer before application of Nitomortar 908

As a Repair Product

• Applied to repair concrete surface faults prior to topcoat application
• Used with fillers to achieve optimal surface smoothness
• Can be applied to form coving on vertical surfaces

Product Advantages

• Early development of initial hardness - minimises maintenance disruption
• Solvent-free formulation - safe for enclosed locations and environmentally friendly
• Moisture-tolerant - can be used in environments where complete surface dryness may be difficult to achieve
• Versatile mixing consistencies - wide range of applications possible
• Pre-weighed quality-controlled materials - ensure consistency and reduce site errors
• HACCP certified - suitable for use in food handling areas
• Complies with AS4020:2018 - suitable for use in contact with drinking water

Coverage & Yield

• As a primer: 5-6 m²/litre
• With fillers (varies by ratio):
  • 1:2 ratio yields 2.4 litres (Fluid paste) - 76 MPa strength
  • 1:3 ratio yields 3.2 litres (Stiff paste) - 56 MPa strength
  • 1:4 ratio yields 4.0 litres (Trowellable) - 50 MPa strength
  • 1:5 ratio yields 5.0 litres (Dry mortar) - 45 MPa strength

Packaging & Supply

Nitomortar 903 is supplied in multiple pack sizes:

*MTO = Made to Order (lead time 14-21 days)

Application Instructions

Surface Preparation

• Remove all grease, oil, chemical contamination, dust, laitance, and loose concrete
• Use scabbling or light bush hammering to provide a sound substrate
• For small area repairs (up to 1m²), concrete should be dry or at least SSD (Saturated Surface Dry)
• For larger flooring applications, concrete must be dry and meet moisture content requirements
• Steel surfaces should be grit blasted to white metal and degreased if necessary

Mixing

• Stir the entire contents of the hardener into the base container
• Mix thoroughly for 3 minutes using a heavy-duty drill and spiral mixer
• Scrape the sides and bottom of the container during mixing
• Important: Once mixed, pour into flat, open paint trays to maximize pot life
• Do not hold the product in the original mixing can as exothermic reaction will reduce pot life
• For mortar applications, use a forced-action mixer at 400-500 rpm with a 120mm helical/spiral mixing paddle on a 1500W mixer

Priming Application

• Apply at a rate of 6 m²/litre for general primer use
• Very porous substrates may require a second coat in patches
• Allow primer to cure and apply coating system within 24 hours
• For dry mortar mixes used for coving or patches, apply as a tack coat prior to mortar application

Storage & Shelf Life

• Store in cool, dry conditions in original, unopened packs
• Shelf life may be reduced when stored at high temperatures and/or high humidity
• Avoid storing in direct sunlight
• Store at temperatures between 5°C and 30°C for optimal preservation

Cleaning

Nitomortar 903 should be removed from tools, equipment, and mixers with Fosroc Solvent 10 immediately after use to prevent hardening.

Exothermic Reaction

• All epoxy systems develop a temperature rise on mixing
• The extent depends on volume-to-surface ratio, ambient temperature, and thermal properties of surrounding materials
• Once mixed as a primer (unfilled), place Nitomortar 903 immediately - do not hold in bulk or re-lid containers
• Do not mix more product than can be used within the 30-minute pot life

Standards Compliance

• HACCP certified for SSZ (Splash or Spill Zone) - suitable for food handling areas
• Complies with AS4020:2018 - tested for contact with drinking water
• Refer to AWQC Report 319383 for certification documentation

References

• [1] Fosroc_Nitomortar_903_TDS.pdf
• [5] Fosroc_Nitomortar_F4_Fillers_TDS.pdf