Extruded pre-stretched polyethylene films
A method of making a pre-stretched plastic packaging film comprising co-extruding a top layer, a bottom layer, and a core layer into a multilayer film intermediate product, wherein the top layer and bottom layer comprise at least about 95 wt % polyethylene resin, and the core layer comprises polyethylene resin and filler particles; stretching the multilayer film intermediate product to impart cavitation in the core layer in the area of the filler particles to form a pre-stretched polyethylene-based film; and rolling the pre-stretched polyethylene-based film onto a roller to form a roll of pre-stretched polyethylene-based film. A multilayer pre-stretched plastic packaging film comprising: a core layer sandwiched between a top layer and a bottom layer wherein the top layer and bottom layer comprise at least about 95 wt % polyethylene, and the core layer comprises filler particles having a particle size of 0.1 to 20 μm in a polyethylene-based matrix comprising at least about 95 wt % polyethylene.
1. A multilayer pre-stretched plastic packaging film comprising:
a core layer sandwiched between a top layer and a bottom layer;
wherein:
the top layer and bottom layer comprise at least about 95 wt % polyethylene;
the core layer comprises filler particles having a particle size of 0.1 to 20 μm in a polyethylene-based matrix comprising at least about 95 wt % polyethylene;
wherein the multilayer pre-stretched plastic packaging film has:
a length in the machine direction and
a first side edge margin, a second side edge margin, and width extending from the first side edge margin to the second side edge margin, the width being perpendicular to the length;
wherein the multilayer pre-stretched plastic packaging film has been cut lengthwise along the first side edge margin such that the first side edge margin comprises a cut edge;
wherein the multilayer pre-stretched plastic packaging film comprises a filler-free segment and a filler-containing segment, the filler-free segment extending widthwise from the first side edge margin toward the second side edge margin and the filler-containing segment extending widthwise from the filler-free segment toward the second side edge margin,
wherein the cut edge is through the filler-free segment.
2. The multilayer pre-stretched plastic packaging film as set forth in claim 1 , wherein the filler-free segment is a first filler-free segment and wherein the cut edge is a first cut edge.
3. The multilayer pre-stretched plastic packaging film as set forth in claim 2 , further comprising a second filler-free segment extending widthwise from the second side edge margin toward the first side edge margin, the filler-containing segment being between the first filler-free segment and the second filler-free segment.
4. The multilayer pre-stretched plastic packaging film as set forth in claim 3 , wherein the multilayer pre-stretched plastic packaging film has been cut lengthwise along the second side edge margin such that the second side edge comprises a cut edge through the second filler-free segment.
5. The multilayer pre-stretched plastic packaging film as set forth in claim 4 , wherein at least one of the first side edge margin and the second side edge margin is folded.
6. The multilayer pre-stretched plastic packaging film as set forth in claim 1 , wherein the top layer is a continuous skin layer.
7. The multilayer pre-stretched plastic packaging film as set forth in claim 6 , wherein the bottom layer is a continuous skin layer.
8. The multilayer pre-stretched plastic packaging film as set forth in claim 1 , wherein the filler-containing segment comprises a set of multiple narrow strips of the filler.
9. The multilayer pre-stretched plastic packaging film as set forth in claim 1 , wherein the filler-containing segment comprises a cavitated area between the top layer and the bottom layer.
10. The multilayer pre-stretched plastic packaging film as set forth in claim 9 , wherein the cavitated area has a first density and non-cavitated polyethylene of the multilayer pre-stretched plastic packaging film has a second density, the first density being between about 50 and about 95% of the second density.
11. The multilayer pre-stretched plastic packaging film as set forth in claim 9 , wherein the cavitated area has an area width and wherein the area width is about 50 to about 98% of the width of the multilayer pre-stretched plastic packaging film.
12. The multilayer pre-stretched plastic packaging film as set forth in claim 1 , wherein the multilayer pre-stretched plastic packaging film is extruded from a specified polyethylene material.
13. The multilayer pre-stretched plastic packaging film as set forth in claim 12 , wherein the multilayer pre-stretched plastic packaging film has an overall density and wherein the overall density is between about 55% and about 98% of a standard material density for a film of the specified polyethylene material devoid of filler particles and cavitation.
14. The multilayer pre-stretched plastic packaging film as set forth in claim 12 , wherein the specified polyethylene material comprises additives.
15. The multilayer pre-stretched plastic packaging film as set forth in claim 1 , wherein the filler particles are inorganic particles.
16. The multilayer pre-stretched plastic packaging film as set forth in claim 15 , wherein the inorganic particles are at least one of calcium carbonate, talc, and mica.
17. The multilayer pre-stretched plastic packaging film as set forth in claim 1 , wherein the filler particles are organic particles.
18. The multilayer pre-stretched plastic packaging film as set forth in claim 15 , wherein the organic particles are at least one of Nylon and polymethyl methacrylate.