Disclosed are improved water-based, polyamide-containing synthetic polymer coating compositions and related products and processes. The coating composition comprises 1 to 40% dry weight of polyamide powder, and can contain higher polyamide content than organic solvent-based coating products containing polyamide and polyurethane. The improved coating compositions are suitable for coating of metal substrates, such as aluminum sheets and panels. The improved coating compositions are also suitable for industrial coil coating processes, forming a thin and uniform coating layer when applied to a metal substrate, such as an aluminum sheet surface. Methods and processes related to production and uses of the coating compositions are described, as well as products produced by the processes using the coating compositions, such as roller shutters and architectural panels.