Q:What are the common types of coatings?
A:Ordinary polyester (PE), silicon-modified polyester (SMP), polyvinylidene fluoride (PVDF), epoxy resin (EP), polyurethane (PU), acrylic acid (AC), silicone (Silicone)
Q:What are the differences in salt spray corrosion resistance among PVDF, epoxy resin, and PE coatings?
A:PVDF/fluorocarbon coating: Fluorocarbon bonds have high bond energy, dense molecular structure, slow salt spray penetration, and can pass tests of more than 1500 hours. It is suitable for coastal projects (such as offshore wind power and port buildings). Epoxy resin: When used as a primer, it has strong adhesion to the substrate, forming a "shielding layer" to block salt penetration. It is often used in ship primers (salt spray tests can reach 2000 hours after matching topcoat).
PE coating: The molecular chain contains ester groups, which may hydrolyze after long-term contact with salt spray. It is only suitable for inland environments with salt spray concentrations of less than 100mg/m³.
Q:What are the differences in chemical corrosion resistance between epoxy resin (EP), PVDF, and SMP coatings?
A:Epoxy resin (EP): Contains epoxy groups in the molecule, which can resist highly corrosive liquids with a pH of 2-12. It is often used in the inner wall of chemical storage tanks and sewage treatment equipment.
PVDF: Its corrosion resistance is close to that of polytetrafluoroethylene (PTFE). It can withstand 90% concentrated sulfuric acid and 30% sodium hydroxide solution. It is suitable for the exterior walls of chemical workshops.
SMP coating: The silicon-oxygen bond improves chemical stability and has better acid rain resistance than PE. It is suitable for industrial plant buildings (such as around steel plants and fertilizer plants).
Q:What are the differences in weather resistance among PVDF coatings, PE coatings, and silicone coatings?
A:PVDF coating: UV absorption rate <5%, after 2000 hours of UV aging test (such as QUV standard), gloss retention rate >85%, color change ΔE <3, suitable for high UV areas (such as plateaus, tropical areas).
PE coating: Powdering may occur after 500 hours of UV aging, and it needs to be repainted every 5-8 years when used in coastal areas.
Silicone coating: Temperature resistance range - 60℃~250℃, not easy to oxidize and corrode at high temperature, suitable for high temperature scenes such as chimneys and engine parts.
Q:How to choose corrosion-resistant coatings in special scenarios?
A:1. Food and medicine industry: FDA certification is required, and epoxy phenolic coating is optional (steam sterilization resistance, corrosion resistance and anti-microbial adhesion).
2. Marine engineering: zinc powder primer + epoxy intermediate paint + fluorocarbon topcoat three-layer system, zinc powder (content ≥ 80%) protects the substrate through sacrificial anode, and the total thickness of the supporting coating is ≥ 200μm.
3. New energy field: photovoltaic bracket uses aluminum-zinc-magnesium coated substrate + PVDF coating, and the salt spray resistance can reach more than 5,000 hours (far exceeding ordinary galvanized substrates).