PURPOSE: To form the adhering flap of an envelope effectively and surely by a method in which while a tape for sealing is interleaved into the flap when the paper vessel excellent in the characteristics of aroma-keeping and gas-barrier is made, the flap is formed.
CONSTITUTION: Flame treatment is applied to the part with about 5mm width of a rear surface-layer at the other side part 10 of the laminated sheet 9 whose end surface has been treated and the resin layer-surface for heat sealing in the tape (a) for seal having been heat and pressure-bonded to one side part 7, thereby melting said treated surfaces under heating respectively. In the interval of said molten state under heating, the other side part 10 is lapped on the side part 7, and said flame treated surfaces are brought in contact to each other, and then said contact parts are pressurized with rubber rollers from arrow-side, whereby a struck part A is formed, and simultaneously the cylindrical body having a rear surface-layer 4 in the laminated sheet 9, as its inner peripheral layer, is formed.
TSUNODA HIROTAKA
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