In addition to conventional spray applications, there are other methods of polyurea coating application, including brushing and rolling. However, the most common way is spray application. These methods are described below. Performing surface preparation before applying polyurea coating is critical to the process. Aromatic polyurea is a low-cost alternative. As far as application methods are concerned, spray application is the most common and economical method.
Surface preparation is key to a successful polyurea coating application:
A successful polyurea coating application begins with proper surface preparation. Polyurea is a durable, highly reflective coating that reduces water and chemical erosion. Because polyurea dries quickly, it can be applied to new or old steel tanks, reducing downtime. Downtime can cost facility owners money. In addition to protecting steel tanks from corrosion, polyurea coatings are quick to set and offer limited structural properties.
Polyureas made from aliphatic diisocyanates have exceptional UV resistance and resist color change when sunlight is exposed. Using these coatings at lower film thicknesses, around 30 mils, makes them ideal for exterior applications. However, polyureas that contain this chemical are expensive due to the complex processing required to create them. Despite these benefits, proper surface preparation is vital for a successful polyurea coating application.
Aromatic polyurea is a low-cost option:
The primary difference between aliphatic and aromatic polyurea is the isocyanate content. Aromatic polyurea is less expensive than aliphatic polyurea but does not have the UV stability of aromatic polyurea. Both varieties offer UV stability and are suitable for chemically challenging environments. Aromatic polyurea is not a good topcoat choice but is a convenient alternative for basecoat applications.
A significant part of the polyurea market is dominated by the industrial sector, which accounted for 30.7% of market revenue in 2015. Growing industrialization is expected to have a positive impact on the market for polyurea coatings. Polyurea coatings are commonly used in automotive, bridge, and marine applications. They are also used as flooring and joint fillers/caulk.
In addition to being transparent, flexible, and lightweight, polyurea is thermosetting under normal conditions. Many processes are available to manufacture polyurea, including direct injection and extrusion. In addition, most polyureas require the use of specialized equipment. A low-cost option is an aromatic polyurea. There are several advantages to using aromatic polyurea for polyurea coatings.
Spray application is the most common method:
In addition to coating concrete, polyurea is also used to coat containment liners, membranes, car park decks, bridges, and offshore applications. The polyurea coating is highly resistant to abrasion and is UV stable. Its formulation consists of five components, the most common of which is diphenylmethane diisocyanate. Other isocyanates, known as aliphatic systems, are used where UV stability is an issue.
Since polyurea cures rapidly and is very durable, it is the ideal solution for waterproofing many surfaces. It is available in potable water-approved formulations for specific applications. The properties of polyurea make it an excellent choice for challenging waterproofing projects, such as wastewater treatment plants, because of its ability to withstand turbulence, erosion, and high levels of hydrogen sulfide gas. It is also very flexible and can be applied more readily to smaller surfaces than other coatings.
A wide range of applications for polyurea coatings has led to the development of numerous applications. For example, spray coatings have been used for chemical processing vessels and liners, floor sealers, protective coatings, and even concrete-mixing tank linings. In addition to layers for these areas, polyurea spray coatings are effective as caulks, reinforcement, and containment systems.
Other methods include brushing and rolling:
Other applications for polyurea coatings include containing liners and rooftop coatings. They also provide a barrier to scratches and reduce bacterial growth. The properties of polyurea coatings make them ideal for use in car parks, bridges, and offshore structures. They are also known for their impact resistance, tensile strength, and durability. The quick-cure properties and low flammability make polyurea an excellent coating material for high-traffic areas.
The best method for polyurea coatings depends on the substrate’s composition, characteristics, and environment. For high-volume coating jobs, high-pressure heated spray units are most effective. In addition, these units need to be designed with low viscosity and high pressure to produce suitable spraying. Other methods include rolling and brushing for polyurea coatings. There are advantages and disadvantages to each application method.