中文摘要：

利用界面聚合法制备了聚脲壁热敏微胶囊材料，其峰值粒径约为0．96μm；热重分析表明，微胶囊囊壁热相变温度范围128～230℃。利用图像密度检测手段得到了材料图像密度随显色控温条件的变化。在150℃下，随显色时间的增加热敏微胶囊的显色密度快速增大，并在7s时达到稳定值1．67，高于110％、5s时获得的稳定显色密度0．35。在控制显色剂D-8熔融状态、微胶囊囊壁热相变程度的基础上，温度是决定热敏微胶囊显色密度的关键因素。显色后纸基热敏涂层由于PVA胶体熔融出现了不规则形貌。

英文摘要：

The thermal sensitive microcapsule with polyurea shell is synthesized with interfacial polymerization method. Peak diameter of the microcapsules is about 0.96μm detected by laser particle diameter analyzer. The weight loss result verifies that the phase change temperature of the microoapsule shell is in the range from 128 to 230~C. Relationship between color-forming density and heat developing time is obtained based on image density detection. The image density increases quickly with increase of heating time at 150% and the stable density 1.67 is obtained after heating for 7 s, which is remarkably higher than the stable density 0.35 heating at 110℃ for 5 s. It can be concluded that the color-forming reaction in thermal sensitive microcapsules is mainly determined by heating temperature on the basis of controlling the melting state of the color developer D-8 and the thermal phase-change degree of the microcapsule shell. After heating development, the surface topography of the thermal sensitive coating on paper base presents irregular structure, which is ascribed to the melting process of PVA colloid in the coating.