The invention belongs to the field of coatings, and provides a low-temperature curing weather-resistant
polyester powder coating and a preparation method thereof. According to the preparation method disclosed by the invention, double-intermediate
collaborative design of a
polyester /
silicon dioxide covalent
nano hybrid intermediate and a latent curing microgel intermediate is adopted, and a covalent bonding nano SiO uniform dispersion
system is constructed through in-situ hydrolytic condensation of a silanized
polyester prepolymer and tetraethoxysilane; carboxyl polyester and tetrahydroxy
amide are partially cross-linked to form latent curing microgel, low-temperature rapid curing at 130-150 DEG C is achieved, the 60-degree glossiness of a
coating film is larger than or equal to 85%, the glossiness
retention rate is larger than or equal to 80% after a
xenon lamp is aged for 500 hours, and the
powder fluidity is larger than or equal to 15 g / 10 s. The technical problems of contradiction between low-temperature curing and weather-resistant long-
term effect, contradiction between nano SiO dispersion and
powder flowability and opposition between optical decoration and
ultraviolet shielding physical limit of an existing
powder coating system are solved, and the
powder coating has wide application value in the fields of aluminum
alloy doors and windows, steel structure protection, household appliance shells, outdoor facilities and the like.