Patent attributes
Another coating part is formed along a sheet short side direction, on a region which is a part of an envelope outer side of a third component sheet and which contacts a flap by folding along a second folding line. A first cutout part and a second cutout part which respectively extend in an extension direction of a first coating part and a second coating part, are respectively formed on both side fringes in the sheet short side direction in the third component sheet. The minimum width of each of the first cutout part and the second cutout part in the sheet short side direction is set longer than a length from the side fringe of the envelope sheet in the sheet short side direction to the inner side fringe of each of the first coating part and the second coating part.
