| 摘要 |
One end of a tubular section is folded to form two triangular or trapezium-shaped flaps symmetrical in relation to the centre line and with their bases opposite, leaving a slot between. The points of the flaps are then folded towards each other along fold lines at right angles to the slot, and secured in place to form the bottom. The tubular section is of flexible heat-sealing material, and after folding the flap points, a label is fixed to them to seal the bottom, this covering the slot to beyond their fold lines. The points are heat-sealed along seams crossing the label ends, after which the points are folded and secured in place. |
