| 摘要 |
<p>The block bottom valved paper sack has a valve hose of plastic sheet glued to the corner fold forming the valve, and protruding beyond the fold edge into the sack interior, being glued at the top to a paper cover sheet. Between the corner fold (6) and the valve hose (15) is a hinging paper sheet (10) extending roughly to the outer corner (14) of the fold, and having a folded-over portion (12) open to the outside, glued to the corner fold. This forms with the valve hose, and cover sheet (21) a flat hose, being glued to them and itself. The valve hose can be of seamless extruded sheet material in hose form.</p> |
