US 11,655,373 B2
Method of preparing electric and temperature dual-control bi-stable color-changing dyes and microcapsules
Shaohai Fu, Wuxi (CN); Liping Zhang, Wuxi (CN); Chengcheng Wang, Wuxi (CN); Mingfei Sheng, Wuxi (CN); and Anli Tian, Wuxi (CN)
Assigned to JIANGNAN UNIVERSITY, Wuxi (CN)
Filed by Jiangnan University, Wuxi (CN)
Filed on Aug. 6, 2021, as Appl. No. 17/395,793.
Application 17/395,793 is a continuation of application No. PCT/CN2020/099093, filed on Jun. 30, 2020.
Claims priority of application No. 201910648872.1 (CN), filed on Jul. 18, 2019.
Prior Publication US 2021/0363355 A1, Nov. 25, 2021
Int. Cl. C09B 9/00 (2006.01); C09B 67/02 (2006.01)
CPC C09B 67/0097 (2013.01) [C09B 9/00 (2013.01)] 5 Claims
 
1. 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.