Nitoseal MS400: UV Resistant Elastomeric Joint Sealant

Overview

Nitoseal MS400 is a high-performance elastomeric trafficable joint sealant engineered for demanding applications requiring robust durability and superior weathering resistance. This advanced product represents a replacement for the earlier Duraflex® formulation and combines the weathering and adhesion performance of silicone sealants with the toughness characteristics of polyurethane sealants.

Technical Description

Nitoseal MS400 is formulated based on Silyl Modified Polymers (Polyurethane hybrid) technology with integrated Duraflex® technology. This hybrid formulation delivers exceptional performance across multiple construction applications, from trafficable floor joints to general building materials requiring reliable joint sealing solutions.

The sealant is available in multiple colors including Concrete Grey, Black, White, and made-to-order custom colours, providing flexibility for aesthetic and functional requirements.

Key Properties & Specifications

Physical Characteristics

Property	Specification
Form	Smooth, non-slump paste
Typical Hardness	42 Shore A
Specific Gravity	1.49
Continuous Service Temperature	-15°C to +70°C
Minimum Application Temperature	5°C

Performance Characteristics

Property	Value
Joint Movement Capability	Total 40% (±20%)
Elongation at Break	340%
Modulus @ 100%	1.15 MPa
Skin Time	50 mins @ 23°C and 50% RH
Tooling Time	25 mins @ 23°C and 50% RH
Cure Time @ 25°C	>2mm / 24h @ 50% RH
VOC Content	12g/L (ASTM D3960)

Environmental Performance

UV Resistance: Nitoseal MS400 demonstrates outstanding UV resistance, maintaining color and integrity under extended ultraviolet exposure, making it suitable for both internal and external applications.

Advantages & Features

Key Benefits

• Easy Application: Extrudes smoothly even at low temperatures with low stringing characteristics
• Long-Lasting Flexibility: 40% joint movement capability accommodates structural shifting and thermal expansion
• Outstanding Weathering & UV Resistance: Maintains colour and integrity in exposed applications
• Excellent Primerless Adhesion: Bonds effectively to concrete, timber, masonry, aluminium, metal, and ceramics without requiring primers
• Aesthetic Properties: Will not stain masonry surfaces
• Paintability: Compatible with water-based paints for customizable finishes
• Rapid Cure: Blister-free, fast cure in high humidity or on saturated surface dry (SSD) conditions
• Low Environmental Impact: Very low VOC (12g/L) with solvent-free formulation
• Chemical Composition: Contains no isocyanate

Manufacturing Origin

Nitoseal MS400 is Australian-made, providing local manufacturing standards and availability.

Design Criteria & Joint Specifications

Joint Width Design

Nitoseal MS400 is designed for sealing movement joints between 10mm and 35mm wide. However, joints as narrow as 5mm and as wide as 50mm can be sealed under suitable conditions.

Width-to-Depth Ratio

The sealant should maintain appropriate width-to-depth ratios:

• 10mm to 20mm wide joints: Minimum depth of 10mm
• Joints wider than 20mm: 2:1 ratio (2mm width for every 1mm depth)

Movement Accommodation Factor

The movement accommodation factor (MAF) must be considered in the design width and spacing of movement joints in structures to ensure optimal performance.

Applications & Uses

Nitoseal MS400 is specified for:

• Trafficable floor joints in pavements and footpaths
• OEM Assembly applications
• Brick, blockwork and paving systems
• Most building materials requiring reliable joint sealing

Application Instructions

Surface Preparation

Joint surfaces must be thoroughly prepared before application:

• Clean and dry (SSD condition) and free from frost
• Remove all dirt, laitance, loose materials, and foreign matter
• Remove rust, scale, and protective lacquers from metal surfaces
• Degrease non-porous surfaces using Fosroc Solvent 10
• Bond Breaker Requirement: All joints must incorporate a bond breaker to prevent sealant contact with the joint back, ensuring optimum performance
  • Shallow joints: Use self-adhesive polyethylene tape
  • Deep joints: Incorporate backing strips such as Expandafoam Backing Rod

Priming Requirements

Excellent adhesion can be achieved on most surfaces without primers. However, adhesion may be improved on some surfaces (such as FC sheet) using Primer 10. Consult Fosroc for specific surface recommendations.

Application Method

1. Load the sausage into a suitable sealant gun
2. Cut a slit at the top of the sausage
3. Replace the end cap and nozzle
4. Extrude firmly into the joint to ensure complete contact with joint faces
5. Tool the sealant into the joint for proper finish

Cleaning

Clean tools immediately after use with Fosroc Solvent 10 to prevent material hardening.

Paintability

Nitoseal MS400 is paintable with water-based paints with the following guidelines:

• Painting typically performed after a thick skin develops (60-90 minutes)
• Can be painted as soon as skinned, but risks damaging the sealant
• Best practice: Paint no later than 7 days after application
• Consider coating flexibility to accommodate expected joint movement

Solvent-Based Paint Application

Do not apply solvent-based paints directly over Nitoseal MS400. First apply water-based paint, allow to dry, then solvent-based paint may be applied.

Supply & Availability

Product Formats

Product Variant	Product Code
Nitoseal MS400 Black 600ml	FC920180-600ML
Nitoseal MS400 Concrete Grey 600ml	FC920181-600ML
Nitoseal MS400 White 600ml	FC930203-600ML
Nitoseal MS400 Special Colour 600ml (MTO)	FC930202-600ML
Nitoseal MS400 Concrete Grey 200L (MTO)	FC920181-200L

Coverage Rate

One 600ml sausage provides coverage of 6 metres of 10mm x 10mm sealant bead.

Make-to-Order Details

Special Colour Variants:

• Minimum order quantity: 4 × 200L drums or 360 × 600ml sausages
• Lead time: 14-21 days from approval of colour

Storage & Shelf Life

Nitoseal MS400 maintains a shelf life of 12 months when kept in original, unopened packaging and stored under the following conditions:

• Temperature: Between +10°C and +25°C
• Humidity: 55% relative humidity
• Storage: Away from direct sunlight and moisture

Limitations & Restrictions

• Do not apply to bituminous surfaces
• Do not allow bitumen to contact Nitoseal MS400
• Not suitable for application under water or continually immersed conditions
• Do not apply to wet surfaces where free water is present

Safety & Documentation

A Safety Data Sheet (SDS) is available from the Fosroc website and should be read carefully prior to use, as application or performance data may change from time to time.

Emergency Contact: In case of emergency, contact any Poisons Information Centre (phone 13 11 26 within Australia) or a doctor for medical advice.

Manufacturer Information

Nitoseal MS400 is manufactured and sold under license from Fosroc International Limited. Fosroc, Nitoseal, and the Fosroc logo are trademarks of Fosroc International Limited, used under license. Duraflex is a registered trademark.

Distributed by: Parchem Construction Supplies Pty Ltd
Location: 1956 Dandenong Rd, Clayton VIC 3168
Phone: 1800 812 864
Website: www.fosroc.com.au
ABN: 80 069 961 968

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References

• [1] Fosroc_Nitoseal_MS400_TDS.pdf
• [2] Fosroc_Nitoseal_MS250_TDS.pdf
• [6] Fosroc_Flamex_XT_TDS.pdf