| 摘要 |
A heavy duty bag for powder or granular material consists of an inner sheet (2) and an outer sheet (4) shifted slightly relative to each other to provide margins for pasting and folded and pasted to form a cylindrical body which is simultaneously formed with an inlet (64) by folding an upper portion (56) of one of the folded portions along substantially triangular lines (50, 52, 54). The upper and lower margins of the cylindrical body are folded and pasted to form the bag. According to the invention, the bag has a closing strip (66) applied with a hot-melt adhesive at an area (68) arranged to cover the inlet (64) of the bag. The remaining area (70) of the strip (66) is attached with a conventional adhesive in the form of overriding to the upper portion (56) of the bag prior to filling the bag with the material, After filling, the closing strip (66) is urged onto the inlet (64) whilst being heated to cause the area (68) to adhere and thus to prevent material leaking through the inlet (64) during transportation and storage of the bag. In an embodiment, a flexible film (74) is interposed between the inner sheet (2) and the outer sheet (4) near to the inlet. An upper end (76) of the film (74) extends into the bag to also ensure that material is prevented from leaking through the inlet (64). |
