Nitobond SBR - Water Resistant Polymer Additive

Product Overview

Nitobond SBR is a water resistant polymer additive and bonding agent designed to improve adhesion to concrete and enhance cementitious materials. It is a modified styrene butadiene rubber emulsion supplied as a ready-to-use white liquid that significantly improves the qualities of site-batched cementitious mortars and slurries.

Key Characteristics

Chemical Composition

Nitobond SBR is composed of:

• Modified styrene butadiene rubber emulsion – the primary bonding component
• Ready-to-use white liquid formulation
• Single component product that requires no mixing prior to use

Physical Properties

Nitobond SBR exhibits several important physical characteristics:

• Single Component Liquid – Can be easily gauged and proportioned as required without requiring multiple components
• Hydrolysis Resistant – Resistant to hydrolysis, making it ideal for both internal and external applications in conjunction with cement
• Solvent Free – Safe for use in enclosed locations

Performance Specifications

Mechanical Properties

Testing of a 3:1 sand:cement mortar containing Nitobond SBR (4 litres per 20kg cement) at 28 days under air-cured conditions per BS 6319 revealed:

Property	Value
Compressive Strength	62 MPa
Tensile Strength	3.3 MPa
Flexural Strength	9 MPa
Slant Shear Bond	53 MPa
VOC Content	29g/litre

Water Resistance & Chemical Properties

• Water Resistance – Improved water resistance of modified mortars
• Chemical Resistance – Addition of Nitobond SBR to cement mortars reduces permeability and helps reduce the rate of attack by aggressive chemicals, acid gases, and water
• Permeability Reduction – Nitobond SBR reduces the permeability of cementitious mortars, improving their resistance to chemicals and water

Advantages & Benefits

Enhanced Performance

• Excellent Bond – Excellent bond to concrete, masonry, stonework, plaster, and blockwork
• Improved Tensile and Flexural Properties – Allow thinner applications of repair mortars
• Single Component Liquid – Can be easily gauged as required
• Improved Cohesion and Workability – Improves the cohesion and internal consistency of cementitious mortars
• Waterproof Repairs – Improves mortars to provide waterproof repairs, renders, and toppings that are highly resistant to freeze/thaw cycling

Application Advantages

• Thinner Applications – The improved tensile and flexural properties from Nitobond SBR enable thinner applications of repair mortars
• Enhanced Adhesion – Improves adhesion properties of cementitious materials
• Versatile Use – Suitable for horizontal, vertical, and overhead repair work

Primary Applications

Material Types

Nitobond SBR is used for improving and bonding:

• Concrete repair mortars
• Cementitious floor toppings and screeds
• Waterproof renders
• Cementitious slurries
• Bonding mortar for tiles

Substrate Applications

• Concrete surfaces
• Masonry and stonework
• Plaster surfaces
• Blockwork
• Ponds and pools (with slurry primer application)
• Water retaining structures
• Tiled pools and water features

Waterproofing Systems

Nitobond SBR is used as a slurry prime coat for permanently immersed applications of waterproofing membranes, particularly:

• Nitoproof 410 – Applied as sand/cement slurry priming, essential for submerged applications such as water tanks and tiled pools
• Waterproof and adhesion enhancement for cement-based screeds and renders applied over waterproofing membranes

Application Specifications

Application Thickness

• Minimum thickness: 6mm
• Horizontal applications: Up to 40mm in single application
• Vertical applications: Up to 15mm in single application
• Overhead applications: Depends largely on substrate profile
• With formwork: Up to 40mm in single application achievable

Substrate Preparation Requirements

Surfaces must be:

• Thoroughly soaked with clean water
• Free of dust, unsound or contaminated material
• Free of plaster, oil, paint, grease, corrosion deposits, or algae
• Roughened to provide good mechanical bond
• Properly primed with slurry primer

Slurry Primer Composition

A slurry primer should be prepared consisting of:

• 1 volume Nitobond SBR
• 1 volume clean water
• 3 volumes fresh cement

Coverage Rate: Approximately 2 to 3 m²/litre

Mixing & Equipment Requirements

Mixing Equipment

• Forced-action mixer is essential – Essential equipment for ensuring thorough mixing
• Mixing speed: 400-500 rpm (slow speed)
• Recommended equipment: Ransom 140 x 600 M14 Helical mixing paddle fitted to heavy-duty mixers such as Ransom 1602 E or equivalent

Typical Mix Designs

Patching and Repair Mortar:

• 20kg GP Cement + 60kg grade 16/30 sharp sand + 4 litres Nitobond SBR + 3 litres clean water
• Yield: 38 litres
• Recommended thickness: 6mm - 40mm

Heavy-Duty Floor Screed:

• 20kg GP Cement + 30kg 3-6mm crushed rock + 30kg grade 16/30 sharp sand + 2.5 litres Nitobond SBR + 2.5 litres clean water
• Yield: 37 litres
• Recommended thickness: 10mm - 40mm

Render:

• 20kg GP Cement + 60kg grade 16/30 sharp sand + 2.5 litres Nitobond SBR + 2.5 litres clean water
• Yield: 37 litres
• Recommended thickness: 6mm - 9mm

Bonding Mortar for Tiles:

• 20kg GP Cement + 50kg grade 16/30 sharp sand + 4 litres Nitobond SBR + 3 litres clean water
• Yield: 33 litres
• Recommended thickness: 6mm to 40mm

Environmental & Safety Specifications

Temperature Working Conditions

• Minimum application temperature: 5°C (should not be applied when temperature is 5°C and falling)
• Cold conditions (down to 5°C): Use warm water (up to 30°C) to accelerate strength development
• High temperature (above 35°C): Material should be stored in shade and cool water used for mixing

Storage Requirements

• Storage conditions: Keep in dry store in original, unopened packaging
• Temperature protection: Protect from frost
• Shelf life: Recommend checking product documentation for specific duration

Environmental Properties

• VOC Content: 29g/litre
• Non-flammable: Product is safe for use in enclosed locations
• Water-based formulation: Environmentally considerate

Safety & Documentation

• Safety Data Sheet (SDS): Available from Fosroc website
• Must be read: Prior to use as application or performance data may change over time

Product Supply & Coverage

Specification	Detail
Product Code (20L)	FC323105-20L
Coverage (theoretical)	Refer to mix designs
Slurry Primer Coverage	Approximately 2 to 3 m²/litre

Note: Coverage figures are theoretical. Due to wastage factors and the variety and nature of possible substrates and mix designs used, practical coverage figures will be reduced.

Curing Requirements

Nitobond SBR mortars, toppings, and renders are cement-based materials and must be:

• Cured immediately after finishing in accordance with good concrete practice
• Treated with Fosroc Concure curing compounds sprayed as a continuous film (recommended)
• Supplemented with polythene sheeting in harsh drying conditions
• Protected from moving water during application
• Protected from heavy rainfall prior to final set to prevent surface scour

References

• [1] Fosroc_Nitobond_SBR_TDS.pdf
• [2] Fosroc_Nitoproof_410_TDS.pdf
• [5] Fosroc_Nitobond_EP_TDS.pdf