| 摘要 |
PURPOSE:To obtain a discoloration time monitoring layer which is used for an indicator label for temperature monitoring and has improved wettability, by forming a continuous film made from an emulsion of particles having a multilayer structure consisting of specified core and shell. CONSTITUTION:A continuous film of a thickness of 0.01-20mum is provided by applying and drying an emulsion of particles which have a multilayer structure consisting of a core comprising a (meth)acrylate copolymer having acrylonitrile as essential component and a shell comprising a (meth)acrylate copolymer having styrene as essential component, and have an average particle diameter of 0.01-20mum and a glass transition point of 80 deg.C or lower between a layer (A) containing microcapsules which hold an oily substance and a layer (B) containing a substance which will cause discoloration in contact with the centents of the microcapsules, with the layers A and B being provided on a support, thus forming a discoloration time monitoring layer which controls the time required for the oil substance flowing out of the microcapsules when they are broken to reach the layer B to cause discoloration.
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