Preparation And Application Of Thermal Responsive Multi-color Phase-changing Microcapsule

Common thermoresponsive color changing materials only change color in two similar colors,which limits the application and development of color-changing materials.Therefore,it is an important research topic to expand the color chromatography of color-changing materials and the research of multi-hued color changing materials,which is of great significance to the development of colorful intelligent color-changing textiles.In order to realize the color change between various colors and control the color change temperature,a series of binary composite phase change materials C_nand Cⁿ（n=1～9）with different phase change points were prepared by melt blending with fatty alcohol A₁,fatty alcohol A₂ and fatty alcohol A₃ as raw materials.Using C_n or Cⁿ,basic color-changing system as the core material,thermally responsive color-changing microcapsules（TCMs）were prepared by in-situ polymerization,and the synthesis process of TCMs was explored.The effects of emulsifier dosage,emulsifying speed and emulsifying time on the synthesis of microcapsules were studied,as well as the effects of the color of dyes in microcapsules,the types and proportion of compound fatty alcohol on the color-changing performance of microcapsules.According to the principle of color matching,the influence of the blending ratio of TCMs used in color matching,the amounts and the types of coating dyes in microcapsules on the multi-hued color-changing effect was discussed.Blended microcapsules were treated on textiles by coating process to prepare thermal-responsive multi-hued color-changing coated fabrics and printed fabrics,realizing the expansion and regulation of multi chromatography.The results were as follows:（1）The phase transition temperature of Cⁿ（n=1～9）series composite fatty alcohols was 20～36℃,while that of C_n was 34～46℃.Compound fatty alcohol was used as the solvent of the color change system,the discoloration temperature was regulated,so as to obtain thermally responsive color change microcapsules with different color change temperatures.（2）The optimized synthesis process of microcapsules was as follows:the dosage of emulsifier was 7%,the emulsifying speed was 400 rmp,and the emulsifying time was 30 min.Under the optimum conditions,the microcapsules had a spherical structure with an average particle size distribution of 3 to 4.5μm.By controlling the color of dyes in microcapsules,TCMs realized the expansion of color change chromatography.（3）XRD,XPS and FTIR tests proved that the color-changing system was successfully coated by wall materials.TG/DTG test showed that TCMs had good thermal stability below 180℃.（4）By mixing two kinds of microcapsules and three kinds of microcapsules,the thermal-responsive multi-hued color-changing microcapsules can realize the color-changing effect of three and four different colors,respectively,such as BMs I（blue-green-yellow）and BMs III（blue-green-brown-orange）.（5）The optimized coating process of direct coating method:aqueous nylon solid slurry as adhesive,the percentage content of microcapsule was 20%,the weight gain was 71.43 g/m²,and the baking temperature was 110℃.Under the optimum process,a series of functional textiles with multi-hued color-changing were prepared by finishing the thermal-responsive multi-hued color-changing microcapsules on the fabrics.