| 摘要 |
A spouted, gable-topped carton has its top closure fin sealed by welding employing an ultrasonic horn and an anvil giving a suitable profile of contour sealing of the fin. There is a straight continuous lengthwise seal where the fin is two-ply and a meandering continuous lengthwise seal where it is four-ply, while the sealed portions of the four-ply spout part of the fin are of lesser total extent in proportion to the area of that spout part than are the sealed portions of the other four-ply part of the fin in proportion to its area. |
