Studies have rarely investigated thermochromic materials at refrigeration temperatures (about 8 °C). In this study, such a temperature indicator that can change color at refrigerated temperature was synthesized. Crystal violet lactone (CVL) and lauryl gallate (LG) were dissolved in methyl laurate (ML) at a phase change temperature of 7 °C. A series of low-temperature reversible thermochromic leuco dyes were obtained and used to prepare low-temperature reversible thermochromic microcapsule (TCM) temperature indicators. The FTIR results show that the thermochromic behavior of TCM temperature indicator was determined by LG controlling CVL to open and close the ring for reversible conversion between the lactone structure (colorless) and conjugated structure (colored). The effects of the mass ratio of the three components (w_CVL:w_LG:w_ML) on the thermochromic behavior were analyzed according to the CIE Lab chromaticity indexes. The total thermochromic color difference between leuco dye and TCM temperature indicator reached the maximum when the w_CVL:w_LG:w_ML was 1:3:125. The TCM temperature indicator gradually changed from dark blue to white from 1 °C to 8 °C. The DSC results show that the decolorization temperature of TCM temperature indicator was very close to the melting point of ML. In addition, microencapsulation prevented the phase separation of leuco dyes and improved the stability of thermochromic materials. The results indicate the enormous potential of TCM temperature indicator for studying thermochromic materials at low temperatures and in temperature monitoring of refrigerated food packages.

很少有研究在冷藏温度（约 8 °C）下研究热致变色材料。本研究合成了这样一种在冷藏温度下会变色的温度指示剂。在 7 °C 的相变温度下，将结晶紫内酯 (CVL) 和没食子酸月桂酯 (LG) 溶解在月桂酸甲酯 (ML) 中。获得了一系列低温可逆热致变色隐色染料，并用于制备低温可逆热致变色微胶囊（TCM）温度指示剂。FTIR结果表明，TCM温度指示剂的热致变色行为是由LG控制CVL打开和关闭环，从而实现内酯结构（无色）和共轭结构（有色）之间的可逆转化。三组分质量比的影响（w _CVL:w _LG :w _ML ) 根据 CIE Lab 色度指标分析热致变色行为。当 w _CVL :w _LG :w _ML是 1:3:125。TCM 温度指示器从 1 °C 到 8 °C 逐渐从深蓝色变为白色。DSC结果表明，中药温度指示剂的脱色温度与ML的熔点非常接近。此外，微囊化防止了无色染料的相分离，提高了热致变色材料的稳定性。结果表明，TCM温度指示剂在研究低温热致变色材料和冷藏食品包装温度监测方面具有巨大潜力。