Polyurethane sealant is the high-strength member of the sealant family. Where silicone is chosen for weathering and MS for paintability, polyurethane is chosen when the joint has to carry load and survive abrasion — concrete expansion joints, industrial floors, vehicle and container bodies.
Before going further, one thing worth stating plainly: we do not currently produce a polyurethane sealant. What we make in polyurethane is one-component foam. This page explains where PU sealant genuinely belongs, and what in our range covers the same jobs.
What polyurethane sealant is good at
- High tensile and tear strength — it holds joints that are working mechanically, not just thermally.
- Abrasion resistance. A silicone joint in a trafficked floor gets worn away; a polyurethane one does not.
- Paintable, like MS and unlike silicone.
- Bonds well to concrete and metal, which is why it dominates civil and transport work.
And what it is not good at
Polyurethane chalks and hardens under prolonged UV, so on a south-facing facade it ages visibly faster than silicone. It is isocyanate-based, which brings handling requirements silicone and MS do not have. And its temperature range is narrower than a neutral silicone’s, which matters in climates that swing from −40 °C to +40 °C across the year.
What we make instead
One-component polyurethane foam. Different product, same chemistry family, and it is what most people actually need when they say “polyurethane” on a window installation. Three can sizes — BY-102 at 65 litres, BY-101 at 70 litres and A1-grade, BY-107 at 80 litres — all applied from −20 °C to +50 °C, expanding 30–50 times and fully cured within 24 hours. Full range: polyurethane foam.
Nail-free adhesives, for the fixing jobs a polyurethane construction adhesive is usually bought for. M1 is inorganic-based with a stated 40–50 kg maximum load and a 15–20 minute working time; M2 is moisture-curing with very high initial grab across wood, gypsum board, stone, cement, tile, metal, plastic and rubber — including damp timber. Full range: nail-free adhesives.
Neutral silicone, for weathering joints where a PU sealant would have been specified out of habit. HP-9900 reaches ≥1.8 MPa tensile with a service range of −50 °C to +150 °C, and unlike polyurethane it does not chalk under UV. Full range: neutral silicone sealants.
Choosing between them
The short version: abrasion and mechanical load → polyurethane. Weathering and movement → silicone. Painting → MS. The full comparison guide puts the four chemistries side by side with the figures we publish.
If you are not sure the job needs polyurethane at all, send the substrate, joint width and expected volume — we will say so if nothing in our range fits. Send an enquiry.
