1.What are the core advantages and applicable scenarios of PVDF coating?
Fluorocarbon resin contains strong chemical bonds C-F bonds in its molecular structure, and has extremely strong chemical stability. It can effectively resist chloride ion penetration, seawater erosion and ultraviolet aging. Its salt spray resistance can reach more than 5,000 hours (far exceeding ordinary coatings), and its service life can reach 15-20 years.
Applicable scenarios: seaside building exterior walls, steel structures (such as lighthouses, dock supports), outdoor metal components, etc.
Note: The cost is relatively high, and professional equipment is required for construction to ensure the uniformity of the coating.
2.What are the core advantages and applicable scenarios of polyurea coatings?
Core advantages: The elastomer coating formed by the reaction of isocyanate and amino compounds has a fast curing speed, no joints, can tightly wrap the substrate, and prevent the intrusion of salt and water; at the same time, it has excellent seawater resistance, chemical corrosion resistance and wear resistance, and can withstand salt spray for more than 3,000 hours.
Applicable scenarios: Seawater storage tanks, dock fenders, ship decks, concrete bridge piers and other parts that are directly in contact with seawater or high salt spray.
Note: Rigid polyurea has slightly weaker UV resistance and needs to be matched with weather-resistant topcoat for outdoor use; elastic polyurea is more suitable for substrates with slight deformation.
3.What are the core advantages and applicable scenarios of epoxy glass flake coating?
Core advantages:
Epoxy resin is used as the base material, and flaky glass flakes (overlapping arrangement) are added to form a "maze effect", which significantly prolongs the chloride ion penetration path and enhances impermeability; the salt spray resistance can reach more than 4,000 hours, and it has strong adhesion to substrates such as steel and concrete, and is suitable for wet base construction. • Applicable scenarios: anti-corrosion primer for seaside steel structures, inner walls of concrete pools, chemical equipment (contact with low-salinity seawater), etc. • Note: The coating is brittle and has average impact resistance. Long-term outdoor use requires a weather-resistant topcoat (such as polyurethane).
4.What are the core advantages and applicable scenarios of modified polyurethane coatings?
Core advantages: Compared with aromatic polyurethane, aliphatic polyurethane has greatly improved UV aging resistance. It also has good seawater and salt spray resistance (salt spray resistance 2000-3000 hours), good flexibility, and can adapt to the deformation caused by thermal expansion and contraction of the substrate to avoid cracking. • Applicable scenarios: metal pipes at the seaside, outdoor furniture, amusement facilities, etc., especially suitable for occasions that require both decorative and salt resistance (multiple colors can be matched). • Note: The temperature resistance is slightly weak (long-term use temperature is recommended to be ≤80℃), avoid direct contact with concentrated salt water.
5.What are the auxiliary principles for coating selection?
Substrate adaptability:
Steel substrate: Preferentially use a composite system of epoxy primer (to enhance adhesion) + fluorocarbon/polyurea topcoat. The primer needs to contain zinc (such as zinc-rich primer) for further corrosion protection. ◦ Concrete substrate: First apply a penetrating sealing primer (to prevent salt from precipitating from the inside), and then apply epoxy glass flake or polyurea coating. Construction environment:
The humidity at the seaside is high, so a low-temperature curing coating (such as modified epoxy) must be selected to avoid blistering of the coating due to humidity; before construction, the surface of the substrate must be thoroughly cleaned of salt, rust and oil (high-pressure fresh water washing + sandblasting can be used).
Cost-effectiveness balance:
If the budget is limited, a multi-layer system of "primer + intermediate paint + topcoat" (such as epoxy primer + glass flake intermediate paint + polyurethane topcoat) can be used, with a salt spray resistance of 2000-3000 hours, and a cost 30%-50% lower than fluorocarbon or polyurea.