Offshore platforms and vessels are particularly exposed to corrosion due to the extreme environmental conditions they endure. The salty seawater, constant humidity, temperature variations, and presence of oxygen and other corrosive elements create a highly aggressive environment for metallic materials. This saline environment accelerates oxidation processes, compromising the structural and functional integrity of these installations. Moreover, continuous exposure to factors such as solar radiation, wave action, marine currents, and biological activity intensifies the corrosion process. Therefore, implementing effective strategies for corrosion prevention and control is essential to ensure the safety and longevity of offshore platforms and vessels.
On a vessel or offshore platform, the most vulnerable elements to corrosion include the hull, constantly in contact with seawater; propulsion systems such as propellers, shafts, and rudders susceptible to galvanic corrosion and erosion; superstructures like decks, masts, and railings exposed to saline air and UV radiation; pipes and valves transporting seawater; electrical and electronic systems affected by high humidity and saline environment; water and fuel storage tanks prone to perforations; anchors and chains constantly submerged in saltwater; navigation and communication equipment requiring corrosion resistance for functionality; and submerged support structures like legs and bases exposed to seawater corrosion and wave action.
To mitigate these effects, protective paints and coatings are applied to these elements. However, these protective layers also face challenges. In addition to corrosion, surface paints and coatings on vessel and offshore platform elements are exposed to various hazards that can cause their fracture or rupture. Continuous exposure to UV radiation from the sun can degrade coatings, making them brittle and prone to cracking. Temperature fluctuations and mechanical action from waves and wind can create surface tensions, leading to delamination and abrasions. Physical impacts, such as equipment impacts or floating debris, can also damage coatings. The presence of aggressive chemicals in seawater and air, such as chlorides and sulfates, can accelerate chemical degradation of paints. Furthermore, biological activity, such as marine organism growth (biofouling), can penetrate and lift coatings, compromising their integrity and protective effectiveness. These combined factors significantly reduce the lifespan of coatings and their corrosion protection.
Poliurea paint is an exceptional solution to address these challenges due to its remarkable properties. Firstly, it is highly resistant and elastic, able to absorb impacts and withstand mechanical stresses without fracturing. Secondly, it cures rapidly regardless of temperature and humidity, making it ideal for marine environments and reducing downtime during painting of protective elements. These combined properties make poliurea an ideal solution for protecting vessels and offshore platforms, ensuring extended lifespan and reliable performance in harsh marine environments.
The application of a polyurea coating with a thickness of 2000 microns or more and extending 50 mm up the pipe and 100 mm onto the platform creates a flexible, liquid-tight, and weather-resistant interface at all platform penetrations with the long-term durability required by the marine industry.
Pure polyureas are formed when a liquid isocyanate is mixed under high pressure with an amine-driven resin solution. Isocyanates are reactive because the double covalent bond linking the carbon atom to the nitrogen and oxygen atoms breaks easily to form single bonds in the more stable tetrahedral configuration around the carbon atom.
Some types of polyureas come as a two-part solution that is mixed at high temperature and pressure (3000 psi at 65°C) in a specially designed sprayer. When applied, the excellent chemical cross-linking produces a dense but flexible surface. The high density makes the coating almost impermeable to abrasion, water, and chemicals.
While epoxies and paints form a solid, rigid layer, the flexibility of pure polyurea coatings allows them to move with the expansion and contraction of the underlying structure as temperatures change.
Protecting maritime structures from corrosion and abrasion is a constant challenge due to the extreme conditions of the marine environment. However, by using specialized coatings and proper application techniques, it is possible to extend the life of these structures and ensure the safety of operations and personnel. Investing in high-quality coatings not only protects the infrastructure but can also generate significant long-term savings by reducing the need for frequent repairs and maintenance.
