Nitoseal MS400: UV Resistant Elastomeric Joint Sealant

Overview

Nitoseal MS400 is a high-performance elastomeric trafficable joint sealant engineered for demanding applications where both strength and durability are essential. This sealant is specifically formulated to deliver outstanding UV resistance while maintaining color and structural integrity in exposed environments.

Key Features and Advantages

Nitoseal MS400 offers a comprehensive set of performance characteristics that make it suitable for diverse construction applications:

• Outstanding UV Resistance: Maintains color and integrity under prolonged ultraviolet exposure, ensuring long-term aesthetic and functional performance
• High Trafficability: Designed for sealing moving or static joints in high-performance applications requiring substantial strength
• Excellent Adhesion: Provides primerless adhesion to concrete, timber, masonry, aluminum, metal, and ceramics without requiring primer application
• 40% Joint Movement Capability: Accommodates total movement of ±20%, allowing flexibility in dynamic applications
• Easy Extrusion: Can be extruded smoothly even at low temperatures
• Non-Staining: Will not stain masonry surfaces, preserving the aesthetic appearance of adjacent materials
• Paintable: Compatible with water-based paints, typically after 60-90 minutes of skin development
• Low VOC Content: Contains only 12g/L VOC, indicating minimal environmental impact
• Solvent-Free Formulation: Contains no isocyanates and is completely solvent-free
• Blister-Free Cure: Achieves blister-free, fast cure in high humidity or on saturated surface dry (SSD) conditions

Chemical Composition and Technology

Nitoseal MS400 is formulated based on Silyl Modified Polymers (Polyurethane hybrid) technology, utilizing Duraflex® technology. This advanced formulation combines the weathering and adhesion performance characteristics of a silicone sealant with the toughness properties of a polyurethane sealant, delivering superior hybrid performance.

Physical and Performance Properties

The product exhibits the following typical properties:

Design and Application Criteria

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. The recommended sealant width-to-depth ratio should maintain a minimum depth of 10mm for joint widths between 10mm and 20mm, and 2:1 for joints wider than 20mm.

Primary Applications

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

Application Instructions

Surface Preparation

Joint surfaces must be thoroughly prepared before sealant application:

• Surfaces must be clean, dry (SSD), and frost-free
• 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: A bond breaker must be used in all joints to prevent sealant contact with the back of the joint and ensure optimum performance
  • For shallow joints: self-adhesive polyethylene tape
  • For deep joints: backing strips such as Expandafoam Backing Rod

Priming Requirements

Excellent adhesion can be achieved on concrete, timber, metals, ceramics, brickwork, and most coating surfaces without primers. On certain surfaces such as FC sheet, adhesion may be improved using Primer 10. Consult Fosroc for specific substrate recommendations.

Sealant Application

• Insert the 600ml sausage into a suitable sausage gun
• Cut a slit at the top of the sausage
• Replace the end cap and nozzle
• Extrude the sealant firmly into the joint to ensure complete contact with joint faces
• Tool the sealant into the joint to achieve proper finish

Cleaning and Finishing

• Clean tools immediately after use with Fosroc Solvent 10
• Nitoseal MS400 is paintable with water-based paints typically after 60-90 minutes of skin development
• Best painting results are achieved within 7 days of sealant application
• Consider the flexibility of coatings being applied to ensure they can accommodate expected joint movement

Limitations and Restrictions

• Do not apply to bituminous surfaces or allow bitumen to contact Nitoseal MS400
• Not suitable for application under water or in continually immersed conditions
• Do not apply to wet surfaces where free water is present
• Do not paint with solvent-based paints directly over Nitoseal MS400; apply water-based paint first, allow to dry, then apply solvent-based paint

Supply and Availability

Nitoseal MS400 is supplied in multiple formats:

Made to Order Requirements: Minimum order quantity 4 × 200L drums with 14-21 day lead time from approval of color.

Standard packaging consists of 600ml sausages supplied in cartons of 12, or 200-litre drums for made-to-order applications.

Coverage Information

One 600ml sausage provides coverage of 6 metres of 10mm × 10mm sealant bead, enabling efficient project planning and material estimation.

Storage Requirements

Nitoseal MS400 has a shelf life of 12 months when maintained in its original, unopened packaging under the following storage conditions:

• Dry storage conditions
• Temperature range: +10°C to +25°C
• Relative humidity: 55%
• Away from direct sunlight and moisture

Safety and Documentation

A Safety Data Sheet (SDS) is available from the Fosroc website and should be read carefully before use. In emergency situations, contact the Poisons Information Centre at 13 11 26 (within Australia) or consult a doctor for advice.

References

• [1] Fosroc_Nitoseal_MS400_TDS.pdf
• [2] Fosroc_Nitoseal_MS250_TDS.pdf
• [3] Fosroc_Nitoseal_PU250_TDS.pdf