| 摘要 |
The bag consists of two walls made from sheets of a multi-layer, synthetic material, welded together along part of the perimeter. One of the walls has two or three rectilinear, longitudinal rough stripes on its inner surface, obtained by hot-printing and extending substantially along the full length of the bag. The stripes are obtained by pressing a welding bar, coated with a rough, non-adhesive material, such as teflon cloth, against the multi-layer sheet forming the wall of the bag. |
