Nano-scale core-shell structural casein based coating latex: Synthesis, characterization and its biodegradability

•Caprolactam-butylacrylate co-modified casein latex was successfully prepared without adding extra emulsifiers.•The obtained latex showed regular core–shell structure, and is less than 80nm in size.•Caprolactam modified casein particles have been verified having emulsifying action with the butylacrylate monomers.•The mechanism for this emulsifier-free emulsion polymerization is proposed.•The as-prepared emulsion was verified has excellent application performance.