| 摘要 |
The invention relates to a sack for granular or powdery bulk products consisting of a tubular plastic film which is closed at both ends by a transverse weld and has a slit serving as filling opening in the front wall near to one transverse weld. The sack is closed by welding a covering sheet made of film over the slit. In order to prevent the slit from being torn open during filling via a filling nozzle and in order to maintain satisfactory welding without impairing the rear wall, a slit strip serving as heat barrier and reinforcement is welded onto the front wall before the sack is filled, said slit being congruent with the slit in the front wall. During the subsequent welding of the covering sheet between welding jaws which clamp the covering sheet, the front wall and the back wall, said heat barrier prevents the back wall from being welded to the front wall or weakened by displacement of softened film material. Additionally, the front wall which is greatly loaded in the region of the slit is made more rigid and reinforced by the welded-on strip, which has an advantageous effect both for cleaning and for handling during opening, filling and closing. <IMAGE>
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