October 21, 2021
I had a lot of questions regarding performance topcoats and how to choose the correct one. Since it seemed I wasn’t alone, I sat down with Dur-A-Flex’s Director of Research and Development, Kyle Smith, to get some answers.
How important is a performance topcoat to a resinous flooring system?
It is one of the most important aspects of a resinous flooring system because as the name describes, topcoat, it’s the coat that sees all of the chemicals and sees all of the traffic. Basically, it’s the strong point of the system.
How do you determine which type of topcoat to use?
You need to understand how that floor is going to be used. What’s the environment that it is going in to, the types of chemicals that it is going to see, the traffic that it is going to see? Is there exposure to UV light? That’s how Dur-A-Flex would normally categorize your topcoat. By looking at things like chemical resistance, abrasion resistance and what type of light exposure there will be. Lastly, what type of chemistry is your system based on? We have epoxies, urethanes, our Accelera product line, and they all have topcoats that are unique or that they use.
What would you say, if any, is the most important consideration?
The most important consideration is knowing the environment that the floor is going to see. Then based on those parameters, identifying what that floor needs to potentially deal with and what it is going to be exposed to. That is how you would start to choose your topcoat. You would base that on the system that you are going to build overall. For example Dur-A-Quartz would have a different topcoat then Poly-Crete MDB .
When you say what the floor would be exposed to, do you mean what’s going to be spilled on it, are you talking about whether or not it’s foot traffic, vehicle traffic, etc.?
Both. Not only that but also is the floor going to be exposed to thermal cycling? Take a hangar for example, where three sides of the building are enclosed but maybe for a hot season the door is open, maybe in the south it may have constant exposure to the elements. Potentially, right? There are a lot of different factors, it’s not just one. You need to know the environment — that’s the overall theme to choosing a topcoat.
What types of topcoats does Dur-A-Flex offer?
Dur-A-Flex offers topcoats that are typically in the urethane family. That chemistry fits nicely with our epoxy systems and our cementitious urethane systems. We also have topcoats for our entire product line. Accelera can be used as a topcoat or as a standalone coating. We also have methyl methacrylate (MMA, our Cryl-A-Flex line), which has topcoats that are unique to it. Dur-A-Flex has a topcoat that fits with whichever chemistry family your system is built on. We usually consider our topcoats to be performance urethanes.
Are the topcoats interchangeable meaning they can be applied to any Dur-A-Flex resinous flooring system?
It depends. For things like cementitious urethane, (our Poly-Crete product line), it tends to be best when you are building the heavier duty systems, mainly Poly-Crete MDB, you want to keep that in the Poly-Crete family because of the environment where those are installed. When you are talking about Hybri-Flex systems we are going to match the topcoat to the base chemistry based on the needs of the environment. Urethanes will go over epoxy systems, Accelera could potentially go over epoxies, and in a rare case you may have a urethane going over an Accelera system. It all depends on the needs of the environment. We do mix and match, but certain topcoats should really stay within that chemistry — mainly Poly-Crete and Cryl-A-Flex.
Within the different chemistries, what differentiates one Dur-A-Flex performance topcoat from another?
Each chemistry is going to give you a unique set of performance properties.
When you think about epoxies, they are general-use systems that fit into many different environments. They can be solid or decorative. Typically those topcoats are going to be our thin film urethanes, products like Armor-Top or Accelera EXT.
Poly-Crete systems are cementitious urethane. They are meant for tough environments, food processing, restaurants — areas where you are going to have big swings in temperature. If you think about meat processing facilities, that might be cool environments that operate at 45 degrees, but then they steam clean the floor, and you need to be sure that your topcoat is going to cycle with the self-level or Poly-Crete chemistry underneath, so that’s why we usually keep it in the Poly-Crete family.
When you look at MMA, or Cryl-A-Flex family, that’s going to be a product that is going to give you very fast turnarounds. Some of the benefits of the T-301 topcoat is its high abrasion resistance and good chemical resistance. It can turn over a project really fast. T-303 is a great topcoat for projects that may face thermal cycling from outdoor conditions. If your system is exposed to outdoor elements — think of a pool deck with the hot sun beating on the surface and then cold water being splashed on it — the T-303 is designed for those conditions.
Can you talk to me a little bit about Novolac topcoats?
Novolac topcoats were designed for acid resistance. Novolac is an epoxy chemistry that can be used in epoxy systems, Shop-Floor is a great one, it can be used with Hybri-Flex EB, and sometimes it can be a topcoat for Poly-Crete MDB — when you don’t need the thermal shock resistance but you need acid resistance. It is usually found in battery charging areas, process areas, or areas using acid cleaners.
Novolac is an epoxy and therefore an aromatic chemistry meaning it is not UV stable. It is a topcoat that is going to change color over time, but what it lacks in UV stability you will gain in the floors’ performance when exposed to higher acid concentrations.
What about Accelera? I hear it is great for chemical resistance and wonderful for healthcare environments? Is there a difference in the strength of the systems whether you are using Accelera regular, EXT or LH?
All of the Accelera family is going to have, for the most part, the same chemical resistance. For those pharmaceutical and hospital areas, where they are using sterilization type cleaners, it is going to hold up really well. That is regardless of whether its, Accelera EXT, LH, or regular formulation. But you are right, that is where that products tend to shine: places where stronger basic [alkaline] cleaners are used and sterilization is key. But it is also a quick turnaround chemistry. You’ll end up with, depending on humidity, anywhere from a 2-5 hour cure, and that’s in January in the northern part of the country if you’re using Accelera EXT. It has a really good chemical resistance to a broad range. It stands out with bases but it is also chemical resistant to certain acids and everything in between.
Which is the most abrasion resistant topcoat?
It’s, by far and away, Armor-Top. Especially when you add part C: Armor-Top grit. In the industry they have a standard test method using a taber abrader. What they do is take a 1,000 gram load for 1,000 cycles, the wheel that spins the coating, think of it as sandpaper. On a taber abrader, your typical epoxies are going to have around a 30 milligram loss. Armor-Top with the part C grit is about 4 milligrams. Its [difference] is pretty significant. So by far and away, Armor-Top would be our most abrasion resistant topcoat. It’s one you want to use where you have heavy wheel traffic, forklifts — it’s great for manufacturing and warehouse environments.
Which is the most chemical resistant topcoat?
Poly-Thane II High Solids is our most chemical resistant topcoat when you look at the wide range of acids and bases and the given concentrations that a chemical might be at. But because of VOC regulations, it is limited where you can put it in the country right now. Probably your next best option would be Armor-Top, especially when it comes to the epoxy systems. Armor-Top also has a very wide range of acid and base resistance, solvents, that sort of thing. But the other topcoat would be Accelera EXT. It’s faster than Armor-Top, so that could be a potential benefit, but it also has a wide range of chemical resistance in general. We talked about how it shines in healthcare and pharmaceutical because of some of the sterilization, but again, that range of acids to bases, solvents, and everything in between, Accelera EXT is another good option.
Are Armor-Top and Accelera both UV resistant?
They both are. They are both aliphatic chemistries, but not only that, they have what we call a UV absorber in them. Think of that like sunscreen. If you put that on top of Dur-A-Glaze # 4 or Shop Floor epoxy grout coat, the UV absorber will protect the coating underneath from turning yellow.
So if I came to you as a customer and said that I am looking for a flooring solution for a battery storage area, does that mean I should first consider systems that offer Novolac as a topcoat?
Yes, definitely. The other things to consider is how do you want that floor to look, what’s the concentration and exposure time? But Novolac would definitely be a good place to start.
Those are epoxy systems, what if my concrete has high moisture?
You could build that system as a Hybri-Flex EB. You could use Poly-Crete SL to deal with the moisture and potentially some higher salts. If you wanted to do a second broadcast you could do that into our Shop Floor resin and hardener, and then ultimately put a grout coat of Novolac on top of that. That would be the best way to build that system when moisture is an issue. That would be my go to.
Anything else we should know about performance topcoats that we didn’t cover?
I think we have covered a lot of ground. Just to reiterate, the most important thing is understanding the environment. That is where I think Dur-A-Flex is unique. You truly have the ability to tailor a system that is going to fit your needs or the customers’ needs, as opposed to just having a single topcoat that is a catchall for everything. So know your environment. That’s the most important thing when it comes to the success of your floor system.
If you have other questions regarding choosing the right flooring system or performance topcoats, your local territory sales manager is a great resource. You can locate who that is on the website or tell us about your project to be connected.
Author: Jes Grant
Jes Grant is the content development manager for Dur-A-Flex. She has over 15 years of experience creating content for various technical industries, and has been featured in several publications for her writing and design work.