Polyurea coatings have some distinct advantages that set them apart from other types of protective coatings. They likewise have some restrictions and unique requirements in order to properly use them. This article examines 8 concerns that must be responded to when thinking about these coatings.
1. What is Polyurea?
Polyurea is an elastomer substance derived from step-growth polymerization, which includes combining synthetic resin and isocyanate-reactive products. Hence, the response of an isocyanate part with a resin mix component part through the active development process of polymerization produces polyurea.
Different formulations of resins and isocyanates can provide the desired setting time, wetness resistance, coloring, flame slowing down properties, and other distinct functions.
A hybrid coating is a polyurea combined in polyurethane in established percentages. The hybrid coating provides specific physical residential or commercial properties of the pure polyurea at a lower cost.
2. How do Aliphatic Polyurea Differ from Aromatic Polyurea?
Polyureas originated from aromatic diisocyanates are distinguished by ultraviolet (UV) light level of sensitivity.
Sunlight exposure or artificial UV light can cause degeneration of the polyurea's physical properties and color modifications such as darkening and chalking. Aromatic polyurea is a low cost option but is not appropriate as a leading coat; it can be appropriate for a base coat application.
Polyureas originated from aliphatic diisocyanates can resist color modification due to sunshine exposure and keep their physical residential or commercial properties even under UV direct exposure conditions. They are chosen for outdoor applications because they can improve visual appeals with a glossy appearance and can be utilized at lower movie densities of around 30 mills. However, they are expensive when compared to aromatic polyureas, due to the complicated processing involved.
3. What are the Unique Features of Polyurea?
There is no coating system that can successfully change polyurea in all respects, due to its distinct physical properties and sturdiness. Nevertheless, it's surface preparation requirements are extremely strict.
Polyurea safeguards wood, concrete and steel surfaces and structures from abrasion and corrosion damage. It can assist maintain a weakening concrete structure and assistance repair work and keep canals intact. It resists scratches, chemicals, oils and salts in industrial and commercial flooring applications. It can likewise protect boats and other vessels by providing protection from splitting and wear and tear.
Advantages of polyurea coatings include:
Really quick setting (curing time normally 2 to 5 minutes) relying on the formulation
Excellent abrasion and scratch resistance
Very stable resistance to weather and ecological conditions
Very helpful elongation qualities
Can be applied in variable temperature level conditions, even in high humidity
Stable heat resistance as much as 130 ° C( 266 ° F )and short-term ranking of 220 ° C( 430 ° F). Coating density can be carefully controlled.
Really efficient bonding on correctly prepared surface areas of wood, cement, concrete and metals.
Outstanding chemical resistance.
Feasibility of low viscosity, therefore making it possible for mixing and spraying at wanted temperature levels.
Can be developed for a very high tensile strength up to 4350 psi.
4. What is the Polyurea Market Outlook?
The global market size in 2015 for all coatings and paints was USD $141.58 billion. Of that, polyurea coatings were greater than USD $500 million, with the construction sector comprising 40% of the market share. The worldwide polyurea coating intake in 2014 was 114.3 kilotons. The global market size in 2017 for polyurea coatings rose to USD $684 million.
Polyurea's market size continues to grow rapidly, partly due to it being approved as an eco-friendly low unpredictable natural compound coating (low VOC). Substitution of more affordable epoxies and other coatings by environment-friendly polyurea coatings is anticipated to trigger a spurt in demand for polyurea. The global market share is expected to reach USD $1.48 billion by 2025, at a CAGR of 10.8% in between 2020 and 2025.
Hybrid polyurea products are expected to be a significant contributor to the polyurea market size because they are less expensive and have excellent abrasion resistance and adhesion to concrete and metallic surfaces. Nevertheless, hybrid polyurea items may be lacking in moisture resistance in addition to heat resistance as compared to pure polyurea coatings. (Learn more about the polyurea market in the article The History and Industry Adoption of Polyurea Coating Systems.).
Faster growth in establishing countries with their increasing requirement to secure infrastructure financial investment, equipment parts, equipment and machine tools might contribute to development in demand. Greater wetness resistance and the quick setting residential or commercial properties of polyurea might generate need for its usage in containment liners, roofing top coatings, bridges, offshore structures and cars and truck parking area applications.
By region, North America has actually had a dominant market share, whereas Asia-Pacific is anticipated to grow faster than other areas due to government-funded facilities projects in China and India as well as foreign financial investment in various sectors of the economy.
5. How does Polyurea Compare to Epoxy and Polyurethane?
Compared to epoxy coatings, polyurea is greatly remarkable in moisture resistance, UV resistance (for aliphatic coatings), abrasion resistance, chemical resistance, temperature resistance and resilience. It likewise has a quicker cure time.
Compared to polyurethane, polyurea has superior durability, chemical resistance and wetness resistance.
6. What are the Significant Applications for Polyurea Coatings?
There are numerous applications that gain from polyurea coatings, including the following:.
Automotive industry and product handling.
The auto industry has actually used polyurea coatings for more than 3 years. The coating is popular because of its effect resistance and other mechanical properties.
Polyurea offers abrasion protection in mining and building equipment, and for lining dumpers that are used for abrasive materials such as coal and metallic ores. It protects conveyors and rollers of conveyor systems that carry abrasive coal, stones and metal ores. (More details from NACE about using polyurea for tank linings.).
It is likewise utilized for bed liners for large business lorries and material handling trucks.
Pipelines, pumps and irrigation systems.
Polyurea provides corrosion and abrasion protection of pipelines that carrying abrasive and corrosive products. It is applied as a base coating to prevent cathodic disbonding.
It is used as a pump coating to decrease cavitation and erosion, and to improve pump output. (For more on this subject, see Erosion Corrosion: Coatings and Other Preventive Measures.) It is likewise used to line aquaculture tanks and ponds, and for canal repair work and leak proofing.
Defense and security sectors.
Due to their tested impact resistance, capability to soak up explosive energy, durability and quick setting functions, polyurea coatings and linings easily discover use in the defense and security sectors.
Polyurea's application in ballistic missile system is well documented. As a military equipment coating, polyurea can contract and broaden with changes in ambient temperature level and form a wetness tight seal. Coatings will be devoid of scratches, dents and abrasion damage, all while making sure an appealing shiny look. A spray coating of polyurea on truck bed liners can decrease vibration and add to security. Coating military structures with polyurea can lessen damage due to bomb blasts.
Health care.
In a medical facility environment, ideally the floor and wall coverings will be resistant to viruses and germs because there is a consistent threat of clients acquiring a secondary infection. Cracks, crevices and scratches on the floor can cause moisture seepage and spread unsafe illness.
Polyurea coatings seal cracks and prevent scratches that may otherwise occur due to frequent scrubbing, therefore minimizing the risk of bacterial propagation. These coatings can help keep sterile conditions in surgical locations, intensive care units and neonatal care units.
Surfaces of steel and concrete bridges.
Polyurea is utilized for the initial coating and as a repair/maintenance coating because of its fast-curing ability, impact resistance, and elongation and tensile strength. Polyurea's structure (molecular chain) makes it an elastomer of high sturdiness. This is the secret of its suitability in building and construction and other fields.
Polyurea coatings can prevent the collapse of concrete structures by efficiently fixing a weakening part of the concrete structure and by providing a protective seal around breaking and degrading concrete. (To find out more about polyurea concrete coatings and other alternatives, read 4 Types of Concrete Floor Coatings - And What You Should Know About Each.).
7. What Application Methods are Best for Polyurea?
Four application techniques are presently utilized:.
1. High pressure hot spray.
This technique consists of:.
Preparing the surface area.
Blending the part.
Carrying out the coating application.
The high pressure approach is selected for very high volume coating tasks. Formulators should prepare a lower viscosity coating at running temperature level to guarantee a beneficial flow of the fluid within the device and a consistent density on the surface.
During initial surface area preparation, oily pollutants and dirt should be removed by means such as abrasive sand blasting. Surface areas ought to be checked for cleanliness to make sure strong adhesion of the polyurea coating. This is an important step to make sure the coating's toughness.
In the mixing stage the prescribed pressure and temperature range need to be kept. Element dosing and mixing must be finished with precision. The spray system need to be designed to maintain pressure along with temperature.
The created mix is sprayed on the clean de-dusted surface. The first coat is produced directly on the surface. A 2nd coat is applied to make sure a leak-proof barrier.
Machines used for polyurea spray coatings must have the ability to maintain temperatures up to 80 ° C( 176 ° F )and pressure up to 210 bars.
2. Warm spray coating.
This approach is selected when the volume of the spray coating job is medium and formulators are able to make sure a low viscosity of fluid mix below 60 ° C (140 ° F).
3. Low pressure cold spray.
In the case of cold spray, formulators should ensure low viscosity at ambient temperatures to enable spray coating. This is a practical approach for little area jobs and repairs.
4. Other techniques.
Roller or brush on methods are utilized when spraying is not practical, such as a little pipe interior coating.
Figure 1. Video demonstrating substrate surface preparation and application of a polyurea coating.
8. What are the Limitations and Critical Issues for Polyurea Coatings?
Polyurea coatings do have some limitations and special factors to consider.
Since the coating is highly reactive and quick-curing, setting of the coating without adequate moistening out time can cause poor adhesion to the substrate. Formulators must ensure complete wetting out of the surface area prior to the coating sets. It is a tricky situation.
Aromatic polyurea coatings might respond to UV radiation, leading to color changes and chalking. The visual appeals are adversely affected by UV radiation. For those applications that require visual appeal, an aliphatic polyurea must be utilized.
Hot spray applications need specialized and advanced spray equipment that have the ability to generate high pressures and high temperatures. Specialists should be particularly trained for this task.
