2. Methyl-methacrylate (MMA)
Next, is a lesser-known chemistry, MMA. This organic compound is most commonly used in acrylic plastics like plexiglass or airplane windows. Pharmaceutical grade MMA is even used as a cement or glue in joint replacements, like a hip.
Known for its durability, MMA makes a great base chemistry for flooring and coating systems. The two largest pros for MMA are its ability to cure 100 percent in one hour and down to -26 C (-15 F) or up to 38 C (100 F) as MMA is not temperature dependent. It is also known for being UV stable which means it can be installed outdoors and will not yellow over time.
The two main cons of MMA are it has a relatively higher material price compared to epoxy. The second is it does give off an odor during installation. It has been described as a sharp, fruity aroma or one that is like a nail salon. Odors need to be managed and considered during any MMA project but is not usually a problem when proper ventilation methods are implemented.
Typically, the advantages of MMA chemistries listed above and its ability to accommodate recoating without mechanical preparation years later, can offset the higher costs of installation and stronger odors. One thing to keep in mind is no resinous system is odorless. Some systems just have less odor than others. MMA contractors are typically highly skilled installers and receive special training to be able to mitigate the odors with airflow. They also have crews prepared to work with a shorter pot life that still allows for an excellent installation curing in one hour.
Urethane coatings are typically applied at a thin millage and as a final topcoat or seal coat to other flooring systems. Urethanes are most commonly created by reacting isocyanates with polyols. Other than floor coatings, urethane chemistry can be used in direct metal paint, truck bed or tank linings, and generic waterproofing.
Urethanes for flooring topcoats are known for their high abrasion resistance, chemical resistance, and UV stability. Most urethanes see their best usage in large, high traffic areas or over top of an epoxy or hybrid system. The downside to urethanes is their sensitivity to moisture and temperature fluctuation. It must be installed within a certain temperature range. Also, like epoxies, urethanes have a longer curing time—varying between eight and 24 hours—which varies by manufacturer as well.