Low gauge stretch wrap film
Stretch wrap films are used to hold goods to pallets during storage and shipping. Multilayer stretch wrap films are provided herein with at least one outer layer of polypropylene and other layers of blends of polyethylenes. In preferred embodiments, stretch wrap films comprise a cling layer comprising a heterogeneously branched ultra low density polyethylene, a non-cling layer, and at least one core layer comprising linear low density polyethylene and low density polyethylene. Preferred embodiments of films of the present technology optimize physical properties enabling the film to have sufficient cling while creating a tolerable noise level upon unwinding. The optimized properties can include good clarity, high load containment, high puncture resistance, high stretch and good tear resistance.
1 . A multilayer stretch film comprising:
a cling layer comprising a heterogeneously branched ultra low density polyethylene and optionally a plastomer;
a non-cling layer comprising a copolymer of propylene and ethylene wherein said copolymer has an ethylene content of about 1% by weight to about 10% by weight; and
at least one core layer comprising from about 94% by weight of the core layer to about 99.9% by weight of the core layer linear low density polyethylene having a density ranging from about 0.890 g/cm 3 to about 0.940 g/cm 3 and a melt index of about 1.0 g/10 min to about 10.0 g/10 min, and from about 0.01% to about 6.0% by weight of the core layer low density polyethylene; and
wherein the stretch film has a gauge that is no greater than about 90 gauge.
2 . The multilayer stretch film of claim 1 , wherein the stretch film has a gauge that is from about 35 gauge to about 90 gauge.
3 . The multilayer stretch film of claim 2 , wherein the stretch film has a gauge that ranges from about 50 gauge to about 80 gauge.
4 . The multilayer stretch film of claim 1 , wherein the linear low density polyethylene is an ethylene copolymerized with a C 3 -C 10 α-olefin.
5 . The multilayer stretch film of claim 1 , wherein the low density polyethylene is an ethylene homopolymer.
6 . The multilayer stretch film of claim 1 , wherein the low density polyethylene is an ethylene copolymer.
7 . The multilayer stretch film of claim 1 , wherein the low density polyethylene is an ethylene copolymerized with at least one selected from the group consisting of vinyl acetate, methyl acrylate, ethyl acrylate, acrylic acid and mixtures thereof.
8 . The multilayer stretch film of claim 1 , wherein the low density polyethylene has a density of about 0.900 g/cm 3 to about 0.940 g/cm 3 and a melt index of 0.1 g/10 min to about 10.0 g/10 min.
9 . The multilayer stretch film of claim 1 , wherein said ultra low density polyethylene is an ethylene copolymerized with a C 3 -C 10 α-olefin and said ultra low density polyethylene has a density from about 0.850 g/cm 3 to 0.900 g/cm 3 and a melt index of 1.0 g/10 min to 20.0 g/10 min.
10 . The multilayer stretch film of claim 1 , having plastomer in an amount from about 1% to about 15% by weight of the cling layer.
11 . The multilayer stretch film of claim 1 , wherein the at least one core layer comprises from about 97% by weight of the core layer to about 99.9% by weight of the core layer linear low density polyethylene having a density ranging from about 0.900 g/cm 3 to about 0.940 g/cm 3 and a melt index of about 1.0 g/10 min to about 10.0 g/10 min, and from about 0.01% to about 3.0% by weight of the core layer low density polyethylene.
12 . A multilayer stretch wrap film comprising:
at least one first layer comprising a heterogeneously branched ultra low density polyethylene and optionally from about 1% by weight to about 40% by weight of a plastomer;
at least one second layer comprising a polypropylene;
at least one third layer comprising a mixture of from about 94% by weight to about 99.9% by weight linear low density polyethylene having a density ranging from about 0.890 g/cm 3 to about 0.940 g/cm 3 and a melt index of about 1.0 g/10 min to about 10.0 g/10 min, and from about 0.01% to about 6.0% by weight low density polyethylene having a density of about 0.900 g/cm 3 to about 0.940 g/cm 3 and a melt index of 0.1 g/10 min to about 10.0 g/10 min;
wherein said third layer is disposed between said first layer and said second layer.
13 . The multilayer stretch film of claim 12 , wherein the stretch film has a gauge from about 35 gauge to about 90 gauge.
14 . The multilayer stretch film of claim 13 , wherein the stretch film has a gauge from about 50 gauge to about 80 gauge.
15 . The multilayer stretch film of claim 12 , wherein the linear low density polyethylene is an ethylene copolymerized with a C 3 -C 10 α-olefin.
16 . The multilayer stretch film of claim 12 , wherein the low density polyethylene is an ethylene homopolymer.
17 . The multilayer stretch film of claim 12 , wherein the low density polyethylene is an ethylene copolymer.
18 . The multilayer stretch film of claim 12 , wherein the low density polyethylene is an ethylene copolymerized with at least one selected from the group consisting of vinyl acetate, methyl acrylate, ethyl acrylate, acrylic acid and mixtures thereof.
19 . The multilayer stretch film as claimed in claim 12 , wherein the ultra low density polyethylene is an ethylene copolymerized with a C 3 -C 10 α-olefin and said ultra low density polyethylene has a density from about 0.850 g/cm 3 to 0.900 g/cm 3 and a melt index of 1.0 g/10 min to 20.0 g/10 min.
20 . The multilayer stretch film as claimed in claim 12 , wherein third layer comprises a mixture of from about 97% by weight to about 99.9% by weight linear low density polyethylene having a density ranging from about 0.900 g/cm 3 to about 0.940 g/cm 3 and a melt index of about 1.0 g/10 min to about 10.0 g/10 min, and from about 0.01% to about 3.0% by weight low density polyethylene having a density of about 0.900 g/cm 3 to about 0.940 g/cm 3 and a melt index of 0.1 g/10 min to about 10.0 g/10 min.