The reality is unless you are a scientist, highly educated or just spend many hours reading and processing the chemicals and subsequent properties that provide a platform for spray bedliners can be dizzying. This page is a good starter to understand the general differences between physical properties of polyurethane, polyurea and poly hybrids. We are exposing this information and continuing to go into more detail in future editorials so that those looking to do professional spray bedliner and other coatings can make a highly informed decision. Do not buy a professional bedliner or bedliner dealership without reading the information on this site first.
Polyurea is a process that involves how to use certain families of chemicals and successfully apply them onto different materials in different environments more than it is a specific product. With that said, Polyurea is typically hard and not very flexible. It resists abrasion and tearing due to high tensile strength. However, its harder surface allows cargo to slip because typically it is smoother than a softer polyurethane application. Polyureas are more expensive than polyurethanes and require specialized application tools and protective equipment to spray such as:
– Spray booths
– high pressure spray equipment
This equals a more expensive investment when starting a business doing spray bed liners.
Polyurethane can be flexible and much softer than polyureas. Like anything there is a trade-off for altering physical properties. In this case a polyurethane spray liner has a higher potential to get gouged due to the lower tensile strength (compared to polyurea). Remember we are talking about materials that are in a class that exhibits very high levels of resistance to tear, gouge and puncture in general. So, this is not implying that the material is weak, simply different than the polyurea model.
Most Professional bedliners are actually a Poly Hybrid. This is a combination of polyurea, polyurethane and other chemicals formulated to provide the best characteristics without compromise. A broad array of aggregates such as rubber, paint chips and sand are sometime added for texture and anti-slip properties.
Poly liners bond to the surface mechanically rather than chemically. That means they need tiny grooves and ridges on which to grip. That’s why the ideal prep work for most of the liners simply involves sanding and thorough cleaning of the area. However, while polyurea is 100 percent hydrophobic (able to be sprayed directly onto ice or water), polyurethane and poly hybrids aren’t, so you should never have a vehicle sprayed after it has been in the rain. The surface must be completely dry unless a polyurea is being applied.
Don’t be fooled by the difference between high and low pressure as well as high and low temperature.
Polyureas require high pressure
There’s high and low pressure and hot and cold applications, although these terms can be misleading. First, low pressure generally gives the applicator more control over the texture. Since many liners don’t use an aggregate and the nonslip surface is developed with the application gun, this is important. Second, “hot” and “cold” are misnomers since liner chemicals have an exothermic reaction when they contact each other after leaving the gun, creating their own heat. In both hot and cold applications, the chemicals reach about 230 degrees F. However, in a heated application, the chemicals are brought to 130-140 degrees F before reaching the gun nozzle.
Low-pressure, cold application results in a softer, more flexible product. High-pressure, hot application results in a harder, less flexible product.
Drying and Curing Time
Before you touch the product, it must be dry. Before you can safely transport a load on your new liner, it must be cured. Cold applications will dry in 20-25 seconds, while hot applications take just 3-5 seconds. Hot applications may be the ticket if you need to spray upside down, such as onto a ceiling. Curing time for almost all spray-ins is 24 hours.
Resistance to Fading
In a nutshell, pretty much every product will fade eventually. Some companies add a UV inhibitor to their product and others may spray one on as a topcoat, but it’s just buying time. Accept it.
Topics about Polys
Detailed Explanation of Polyurethanes and Polyureas