Epoxy Resin: In bridge primer coatings, two-component epoxy resin acts like a bulletproof vest for steel. This material undergoes a chemical reaction with an amine curing agent to form a dense, three-dimensional network structure that resists the triple attack of acid rain, salt spray, and ultraviolet radiation. It is particularly suitable for cross-river bridges with large temperature differences, achieving an adhesion strength of over 10 MPa to steel and remaining stable even in humid environments.
Zinc-Rich Primer: Zinc-rich primers with a zinc content exceeding 80% utilize an electrochemical protection principle, where zinc powder acts like a guardian, preferentially reacting with corrosive media. This type of material is particularly suitable for coastal bridges; even when the coating develops micro-cracks, the self-sacrificing properties of zinc still protect the substrate. During application, attention should be paid to zinc powder settling; it is recommended to use specialized stirring equipment to maintain uniform suspension.
Innovative Breakthroughs in Environmentally Friendly Materials: Water-based inorganic zinc-rich and graphene-modified coatings are becoming a new trend. The former uses water to replace organic solvents, reducing VOC emissions by 90%; the latter incorporates nano-scale graphene sheets, enabling the coating to withstand salt spray for over 4000 hours. A new type of silane-modified polyurethane primer used on a certain Yangtze River bridge has extended the construction window by three times while maintaining its anti-corrosion performance.
