Silane-Based Metal Protective Coating for Hot-Dip Zn and Al-Zn Substrates

The patent uses a composite coating system comprising multiple layers: a base coat containing silane coupling agents and promoters adhering to the metallic substrate, and a top coat containing water-soluble film formation resins and silicon oxide packing. This multi-layer composite structure provides synergistic effects that simultaneously improve corrosion resistance, water resistance, thermal resistance, and fingerprint resistance beyond what single conventional coatings can achieve.

The patent modifies the chemical composition parameters of the coating by incorporating specific silane derivatives (formula I and II), promoters (cellulose derivatives), and controlling the water content (5-50 wt%). These parameter changes in the coating formulation enable the formation of a protective film with enhanced and balanced resistance properties against multiple harmful factors including corrosion, water, heat, and fingerprints.

The patent changes the chemical composition parameters by replacing conventional passivating agents with silane coupling agents (formula I and II) and specific promoters. The water content is controlled at 5-50 wt%, and the coating is applied at controlled temperatures (20-100°C). These parameter modifications maintain ease of manufacture through water-soluble components while dramatically improving the protective film's reliability against corrosion, water, thermal, and fingerprint damage.

The silane coupling agents act as intermediaries between the metallic substrate and the protective coating layers. They form chemical bonds with the metal surface while also being compatible with the organic resin matrix, thereby improving adhesion and overall protective performance without complicating the manufacturing process.