| 摘要 |
<p>A flexible co-extruded 3-layer film comprises outer layers of high pressure, low density polyethylene and a core layers of low pressure, low density polyethylene. The film is formed by a conventional blown film tubular extrusion process at a throughput rate of 4-25 (4-20) 1bs/hr per inch of die at 350-600(350-470) deg.F. Pref. overall film thickness is 1.0-3.0(1.5) mil, the thickness of the outside layers is 0.18-0.35 mil each and ratio of the thickness of the respective layers is 1:3:1. The film tensile strength in the transverse direction is at least 4.0 1bs/inch and this value is higher tnan that of a control film in which the core and outer layers are of the same high pressure low density polyethylene.</p> |
