Packaging sheet, and packaging container and packaging method using the packaging sheet

A packaging sheet comprising:

• a heat seal layer for thermally welding by heating;
• a protective layer including a filler, a lubricant and a binder;
• an intermediate layer including a core-shell type particle;
• a heat-sensitive layer including a color developing material that develops a color by heating;
• and
• a base material layer that secures a strength and protects the heat-sensitive layer, wherein:
• the heat seal layer, the protective layer, the intermediate layer, the heat-sensitive layer, and the base material layer are provided in this order from a back surface side in a thickness direction;
• the packaging sheet is transparent before the heat-sensitive layer develops the color;
• and
• the packaging sheet further comprises a printing layer on which at least one of an ink or a dye is printed, the printing layer being arranged on the back surface side of at least a part of the base material layer, the printing layer being arranged between the base material layer and the heat-sensitive layer or between the heat-sensitive layer and the heat seal layer.