In the present contribution, the optimization of coating properties of structured self-crosslinking latexes based on diacetone acrylamide and adipic acid dihydrazide crosslinking system by varying particle design and molar mass was investigated. Latexes were prepared by the semi-continuous non-seeded emulsion polymerization of methyl methacrylate, butyl acrylate, diacetone acrylamide and methacrylic acid as main monomers. Two series of latex particles of hard-core/soft-shell or soft-core/hard-shell design were synthesized with a predominant soft phase. In both series, molar mass of the soft phase was gradually reduced by isooctyl 3-mercaptopropionate included in the synthesis. The results show that desired coating properties can be tailored successfully by varying the molar mass and particle design. Better properties exhibited coatings drawdowned from latexes of soft-core/hard-shell particle design. A moderate reduction of molar mass of emulsion copolymers caused a significant improvement of adhesion and blocking resistance, obviously due to enhanced coalescence leading to favoured inter-particle diffusion of copolymer molecules of reduced molar mass.
Volume 111, October 2017, Pages 258–266