| 摘要 |
<p>A cross-oriented multi-layer laminated plastic film is produced by first providing a flattened tubular plastic film having a outer plastic film layer with a first melting temperature and an inner plastic film layer with a second melting temperature lower than the first melting temperature, the outer plastic film layer having a molecular orientation substantially in the direction of the length of the tubular plastic film. The flattened tubular plastic film is passed from an expanding station in an expanded condition along a predetermined path in the direction of the length of said film to a collapsing station in a continuous manner. The expanded tubular plastic film is rotated about the predetermined path as the film passes from the expanding station to the collapsing station to effect cross-orientation of the outer film layer in directions inclined to the direction of travel of the tubular plastic film. The tubular plastic film is flattened at the collapsing station and pressure is applied to the flattened film at a temperature high enough to soften the inner plastic film but low enough not to soften the outer plastic film layer to an extent to cause the outer plastic film layer to lose its molecular orientation. The said pressure causes the opposite sides of the tubular plastic film to engage one another and to cause adjacent inner film layers to become bonded together and to the outer film layers to form a cross-oriented multi-layer laminated plastic film.</p> |
