Not sure on how much sealant you'll need? Use our calculator to find out.
For expansion joints, precast panels, and structural connections requiring reliable elastomeric movement, PU25 Polyurethane Adhesive provides a highly flexible seal that accommodates up to 25% joint movement. Tested to AS/NZS 4020 for potable water contact and AS1530.3 for low ignitability, this medium-modulus sealant is suitable for sealing and adhering in interior, exterior, and below-waterline applications once cured.
PU25 Polyurethane Adhesive cures via reaction with atmospheric moisture to form a tough, permanently elastic, and dustproof joint seal. With a Shore A hardness of 25 after 14 days and a low modulus of elongation (0.4 MPa @ 100%), it absorbs joint stress across materials with differing thermal exposure coefficients without tearing or losing adhesion. The formulation incorporates biological resistance that inhibits mould and mildew growth in hot and humid environments, and it has passed accelerated UV and weathering exposure testing beyond ASTM C793-05 and ISO 11431 without chalking, cracking, or yellowing.
Suitable for perimeter sealing, connection joints, and structural bonding on these substrates:
To allow correct movement, design joints to a 2:1 width-to-depth ratio. Internal joints must have a minimum width and depth of 5mm. External joints must be a minimum of 10mm wide. The maximum joint width is 30mm, and the maximum depth is 15mm. Use a closed-cell backing rod 25% larger than the joint width to control depth and prevent three-sided adhesion.
Apply when substrate and air temperatures are between 5°C and 40°C. Concrete must be cured for a minimum of 28 days prior to application. Clean non-porous surfaces using a two-wipe process with Acetone or 100% White Spirits.
How much movement can PU25 accommodate?
It is rated for ±25% joint movement to ASTM C 719.
Is PU25 suitable for potable water contact?
Yes. It has been tested to AS/NZS 4020.
What joint size can PU25 be used in?
Maximum joint width is 30mm and maximum depth is 15mm, with a 2:1 width-to-depth ratio used for movement joints.
Can PU25 be used in swimming pools?
Do not use it in internal swimming pools with high chlorine exposure.
| Property | Value |
|---|---|
| Product Type | Polyurethane |
| Curing System | Moisture |
| Cure Rate | 3 mm / 24 Hours |
| Density (Black) | 1.15 g/cm3 |
| Density | 1.16 ± 0.02 g/cm3 |
| Shore A Hardness | 25 (after 14 days) |
| Movement Capability | ± 25% |
| Tear Strength | 6.5 N/mm |
| Elongation | > 400% |
| Modulus | 0.4 MPa @ 100% |
| Application Temperature | +5°C to +35°C |
| Service Temperature | -40ºC to +80ºC |
| Pot Life | 25 min @ 23ºC & 50% RH |
| Skin Time | 60 min @ 23ºC & 50% RH |
| VOC Content | < 1.5 g/l |
| VOC (European 2004/42/CE) | 95 g/l |
| Shelf Life | 12 months in original packaging |
| Storage Temperature | Cool Dry between 10ºC and 35ºC |
| UV Resistance | Good |
| Chemical Resistance | Excellent for water, detergent solutions, moderately diluted acids & alkalis, petrol & oil for short periods |
| Accelerated Testing UV & Weathering | No chalking, no cracks or yellowing (beyond ASTM C793-05, ISO11431 & ISO EN 14187-8) |
| Fire Performance | Ignitability Index 0, Spread of Flame Index 0, Heat Evolved Index 0, Smoke Developed Index 0-1 |
| Full Cure | 3mm / 24Hours |
| Specific Gravity | Black: 1.15. Others: 1.16±0.02 |
| Storage Conditions | Cool Dry between 10ºC and 35ºC |
Here are some common examples on where Adheseal PU25 Polyurethane Adhesive used by our customers.
