When we talk about polyureas and polyurethanes, we tend to focus on the end result: a watertight roof, a hard-wearing floor or a protected tank. However, for these polyurea and polyurethane systems to reach that optimal performance, the material must make a critical journey: changing from liquid to solid right in the middle of the job.
At Krypton Chemical, we don’t leave the performance of our polyureas and polyurethanes to chance. The key to why a resin can be sprayed without clogging, or why a polyurea doesn’t sag on a vertical wall, lies in a fascinating field: rheology.
What is rheology and why should you care?
Rheology is the science that studies how materials flow and deform when a force is applied to them. In our sector, it is the difference between a product that goes on ‘like silk’ and one that causes problems in the machinery.
To understand this, we need to consider two fundamental concepts:
- Viscosity: This is the ‘resistance’ to flow. Not all resins flow in the same way; some are designed to be more fluid, whilst others are more structured.
- Elasticity: This is the material’s ability to return to its original shape after being deformed, which is essential in polyureas and polyurethanes subjected to continuous stress.
Most of our systems are viscoelastic: they combine both properties. They behave in one way under the pressure of a spraying machine and in a very different way once applied to the substrate.
The secret of non-Newtonian fluids
Unlike water (which remains fluid regardless of the pressure), Krypton’s polyurea and polyurethane systems are non-Newtonian fluids. Their viscosity changes depending on the stress applied.
- During application: When passed through a spray gun nozzle or applied with a roller, these resins reduce in viscosity, allowing them to flow properly.
- After application (thixotropy): This is where the magic happens. Thanks to thixotropy, the resins quickly regain their structure once applied. This allows a polyurea to be applied to a vertical wall without the product running down onto the floor.
From liquid to solid: Guaranteed performance
The rheological study does not end when the applicator puts the tool away. Once cured, the resin becomes a viscoelastic solid with advanced mechanical properties.
At Krypton Chemical, we analyse how this solid behaves over time:
- How will they respond to thermal expansion?
- How will these resins respond to sustained loading (creep)?
- Will they retain their resilience following an impact?
Understanding rheology enables us to formulate and develop products that are not only durable but also user-friendly. We optimise each formulation to ensure complete control on site and to ensure that the final result exceeds mechanical expectations.
In short, rheology is the tool that enables us to transform the behaviour of different polyureas and polyurethanes into reliable solutions for waterproofing, flooring and industrial coatings.
Do you have a project with complex technical requirements or challenging vertical surfaces?
Get in touch with our technical team and we’ll help you design the perfect solution for your project.
- During application: When passed through a spray gun nozzle or applied with a roller, these resins reduce in viscosity, allowing them to flow properly.
- After application (thixotropy): This is where the magic happens. Thanks to thixotropy, the resins quickly regain their structure once applied. This allows a polyurea to be applied to a vertical wall without the product running down onto the floor.
