Method of preparing electric and temperature dual-control bi-stable color-changing dyes and microcapsules

A method of preparing an electric and temperature dual-control bi-stable color changing microcapsules, comprising the step of:

• (1) preparing a dual-control compound:
• heating and stirring an electric and temperature dual-control bi-stable color-changing dye to form a dual-control compound in uniform mixed solution;
• wherein the electric and temperature dual-control bi-stable color-changing dye, comprising a leuco dye, an electrolyte and an organic solid material, wherein the leuco dye is 2′-chloro-6′-(diethylamino)fluoran;
• the electrolyte is tetrabutylammonium perchlorate;
• the organic solid material is selected from the group consisting of stearyl alcohol, cetyl alcohol, myristyl alcohol, myristic acid, palmitic acid, stearic acid, glyceryl monostearate, glycerin monostearate, glyceryl laurate, p-azoxyanisole, diphenyl carbonate, phenyl salicylate, phenyl stearate and benzyl benzoate;
• and a ratio of the leuco dye to the electrolyte to the organic solid material is 1:2-10:15-50;
• and
• (2) preparation of dual-control bi-stable microcapsules:
• dropwise adding the dual-control compound obtained in step (1) to an aqueous solution containing an emulsifier, the emulsifier accounting for 25-100% by mass of the dual-control compound, and carrying out high-speed emulsification to form a uniform dye dispersion;
• dropwise adding monomers accounting for 20-100% by mass of the dual-control compound to the dye dispersion, and continuing emulsification for 10-20 minutes;
• and then, transferring the emulsified dispersion into a four-neck flask with a reflux condenser and a stirring device, after introducing nitrogen for 5-30 minutes, raising a temperature to 55-75° C. at a stirring speed of 250-500 r/min, after reaching a reaction temperature, dropwise adding an initiator accounting for 0.1-1% of a total amount of the monomers, keeping the temperature to react for 2-6 hours, and after the completion of the reaction, washing a product with water and drying the product to obtain the dual-control bi-stable microcapsules.