Nitoseal PU400 - Polyurethane Joint Sealant

Product Description

Nitoseal PU400 is a high-performance, low modulus elastomeric joint sealant and adhesive based on polyurethane technology that cures through exposure to atmospheric moisture. It is a flexible polyurethane product specifically engineered for multiple applications within flooring and structural systems, forming a waterproof and durable seal ideal for exterior applications.

Primary Applications

Nitoseal PU400 is designed for the following uses:

• Trafficable floor joints - sealing expansion and movement joints in flooring systems suitable for foot and light vehicle traffic
• Water retaining structures - sealing metal or concrete water retaining structures to prevent water leakage
• Concrete infrastructure - sealing joints in concrete culverts, pipes, and concrete wall panels
• Structural assembly - metal frame building assembly, cover plates, bolted lap joints, and pipe penetrations in walls and floors
• Substrate joints - sealing substrate joints following Nitoflor PU600 flooring system application
• Coving details - forming coving details at right angle bends for structural integrity in waterproofing applications

Design Specifications

Joint Width Capability

Nitoseal PU400 is designed for sealing joints between 10mm and 35mm wide. However, under suitable conditions, it can seal joints as narrow as 5mm and as wide as 50mm. The sealant width-to-depth ratio should be maintained at a minimum depth of 10mm for joint widths between 10mm and 20mm, and 2:1 for joint widths greater than 20mm.

Movement Accommodation

The movement accommodation factor (MAF) is ±12.5% (total 25%), enabling the sealant to accommodate significant joint movement while maintaining effective sealing performance.

Technical Properties

Key Advantages

• Ideal for wide floor joints
• Tough and abrasion resistant
• Suitable for foot and light vehicle traffic areas
• Excellent primerless adhesion to multiple substrates
• Low stringing and low odour
• Weather resistant and suitable for exterior applications
• Easy to gun out
• Suitable for water immersed applications when used with appropriate primer (Primer 13)
• Suitable for use in contact with drinking water

Standards Compliance

Nitoseal PU400 has been tested to comply with AS4020:2018 Australian standards specification. Refer to AWQC Report 390492, with copies available on the Fosroc website.

Supply and Coverage

Product Supply: Nitoseal PU400 is supplied in 600ml foil sausages in cartons of 12. The specific variant available is:

• Nitoseal PU400 Concrete Grey: FC920121-600ML

Coverage Rate: One 600ml sausage provides coverage of 3 metres of 20mm x 10mm sealant bead.

Storage Requirements

Shelf Life: 18 months from date of manufacture when kept in original, unopened packaging under the following conditions:

• Stored in dry conditions
• Temperature between +10°C and 25°C
• Relative humidity of 55%
• Away from direct sunlight and moisture

Application Instructions

Surface Preparation

• Joint surfaces must be thoroughly dry, clean, and frost free
• Remove all dirt, laitance, curing compounds, form release agents, loose materials, and foreign matter from joint faces
• Remove rust, scale, and protective lacquers from metal surfaces
• Degrease non-porous surfaces using Fosroc Solvent 10
• A bond breaker must be used in all joints to prevent sealant contact with the back of the joint
• Deep joints should incorporate a backing strip such as Expandafoam or Hydrocell

Priming Requirements

• Priming of porous substrates is recommended for optimum adhesion
• Good adhesion can be achieved on concrete, timber, metals, ceramics, brickwork, and most coating surfaces without primers
• Use Primer 21 for concrete and other porous materials
• Use Primer 4 for non-porous materials such as metals
• Primer 13 must be used on porous surfaces if the Nitoseal PU400 is to be water immersed

Application Process

• Apply using a suitable 600ml sealant gun
• Insert the sausage into the gun and cut a slit in the top
• Replace the end cap and apply the sealant
• Extrude sealant firmly into the joint to ensure complete contact with joint faces
• Smooth finish if necessary with a spatula

Cleaning

• Clean tools immediately after use with Fosroc Solvent 10

Limitations

Swimming pools: Nitoseal PU400 is not suitable for sealing joints in swimming pools. Nitoseal SC600 is recommended for these applications.

Bituminous surfaces: Do not apply Nitoseal PU400 to bituminous surfaces, nor allow bitumen to contact the sealant. Nitoseal MB175 is recommended for these applications.

Paintability: Although polyurethane sealants may accept painting with acrylic coatings, plasticizers can migrate over time and stain coating surfaces. Fosroc does not recommend painting over Nitoseal PU400 and recommends using Nitoseal MS250 for applications requiring paintability.

Related Products and Integration

Nitoseal PU400 functions as part of comprehensive flooring and waterproofing systems:

• Used following application of Nitoflor PU600 flooring systems
• May precede application of Nitoproof 210 in waterproofing applications
• Serves as an alternative to Nitoseal PU250 for sealing and detailing work
• Used alongside movement joint preparation before Nitoproof 910 application
• Recommended as an alternative to Nitoseal PU400 for swimming pools where Nitoseal SC600 should be used instead

References

• [1] Fosroc_Nitoseal_PU400_TDS.pdf
• [2] Fosroc_Nitoseal_PU250_TDS.pdf
• [3] Fosroc_Nitoseal_MS400_TDS.pdf
• [7] Fosroc_Nitoflor_FC150_HP-SL_Self_Leveller_TDS.pdf
• [8] Fosroc_Nitoflor_PU600_TDS.pdf