Aqueous latexes of copolymers of vinylidene chloride (VDC) with an acrylate, namely, methyl acrylate (MA), ethyl acrylate (EA), butyl acrylate (BA), or 2-ethylhexyl acrylate (EHA), were employed to form a double-layer coating film for the heavy-duty anticorrosion of metal. Measurements of the water-vapor transmission rate and oxygen-gas transmission rate and electrochemical impedance spectroscopy (EIS) demonstrated that the barrier properties of MA-VDC and EA-VDC films were better than those of BA-VDC and EHA-VDC films. Among the MA-VDC and EA-VDC coatings, EA-VDC85 showed better comprehensive properties and, thus, was selected as the top layer of the designed double-layer coating film. Adhesion tests demonstrated that the BA-VDC and EA-VDC coatings had better adhesion to tinplates than the MA VDC and EA VDC coatings and, thus, were suitable for use as the bottom layer of the designed double-layer coating film. The characterizations of the double-layer coating films by adhesion tests and EIS showed that BA-VDC75 was the optimal bottom layer. Under harsh salt-spray corrosion conditions, the optimal double-layer coating film (ca. 50-mu m thickness) with EA-VDC85 as the top layer and BA-VDC75 as the bottom layer could protect tinplate well for at least 800 h, and the adhesion of the coating film to the tinplate was still excellent even after 1000 h of corrosion. Scanning electron microscopy, differential scanning calorimetry, and Fourier-transform infrared spectroscopy were used to evaluate the corroded double-layer coating films.