Effects of the addition mode and amount of organic montmorillonite in soft-core/hard-shell emulsion on fire protection, water resistance and stability of fire retardant coating

•A novel organic-inorganic soft-core/hard-shell hybrid emulsion was used as the film former of the waterborne intumescent fire retardant coating and greatly improved the fire resistance performance.•The optimum addition modes of OMMT in soft core hard shell emulsion was shown to be in core layer.•The performances of emulsion and coatings, such as the water resistance, fire resistance and film forming property, were improved by combining adding OMMT into soft core phase with the structure of soft core and cross-linking hard shell.