| 摘要 |
<p>A net formed from partially crystalline synthetic material is made by first forming a plurality of parallel rows of overlapping slits in a solid, biaxially oriented shrinkable sheet of plastic film, such as polypropylene. The sheet is heated to produce a film lattice through shrinkage and thereafter stretched in the longitudinal direction while maintained at a temperature below the crystalline melting point, thereby causing the web portions to be stretched into thin filaments while the intersection portions remain undrawn. The resulting net comprises rhomboid-shaped meshes defined by the filaments and intersections and is expandable in a direction transverse to the net by a multiple of the width of the net.</p> |
