WO2025029960A1

WO2025029960A1 - Multilayer stretch films

Info

Publication number: WO2025029960A1
Application number: PCT/US2024/040446
Authority: WO
Inventors: Jonathan Mubarak Ali MOGHAL; Eugene Micheal REDDY; Micheal ELWORTHY; Anthony Charles WILMOTT; Alexander BAUMBACH; Christelle GILSON
Original assignee: Signode Industrial Group LLC
Current assignee: Signode Industrial Group LLC
Priority date: 2023-08-01
Filing date: 2024-07-31
Publication date: 2025-02-06
Anticipated expiration: 2026-02-01

Abstract

Various embodiments of the present disclosure provide a multilayer stretch film and an oriented stretch film, for example, resulting from stretching the multilayer stretch film. The multilayer stretch film includes a first layer comprising a first polymer resin, a second layer comprising a polymer material, and a core layer disposed between the first layer and the second layer. The core layer comprises graphene. The oriented stretch film has a thickness in the range of about 4 μm to about 10 μm.

Description

MULTILAYER STRETCH FILMS

PRIORITY

[1] This application claims priority to and the benefit of U.S. Provisional 63/530,253, filed August 1, 2023, and U.S. Provisional 63/544,627, filed October 17, 2023, the entire contents of each are incorporated by reference.

FIELD

[2] The present disclosure relates to multilayer stretch films used to wrap, unitize, or otherwise secure items for ease of transport or storage. More particularly, the disclosure relates to multilayer stretch films having a core layer including graphene. The present disclosure also relates to oriented stretch films, for example, resulting from stretching the multilayer stretch films as disclosed herein.

BACKGROUND

[3] Plastic stretch films are frequently used to securely wrap or hold an article or a collection of articles for shipping or storage purposes. They can be monolayer or multilayer films designed to stretch in response to an applied force. For example, the metal industry often uses stretch films to unitize heavy items or loads, such as large rolls of feedstock materials (e.g., steel or aluminum coils). These films are typically multilayer films and can self-seal when portions of them are overlapped.

SUMMARY

[4] Various embodiments of the present disclosure provide multilayer stretch films. The multilayer stretch film has a core layer including graphene. The multilayer stretch film of the present disclosure provides a balance of desired physical properties (e.g., mechanical and barrier performance) compared to other laminated films. [5] In one embodiment, a multilayer stretch film comprises a first layer comprising a first polymer resin, a second layer comprising a polymer material, and a core layer disposed between the first layer and the second layer. The core layer comprises graphene.

[6] In one embodiment, a multilayer stretch film comprises at least one first layers, at least one second layers, and a core layer disposed between the at least one first layers and the at least one second layers. Each of the at least one first layers comprises a first polymer resin. Each of the at least one second layers comprises a polymer material. The core layer comprises graphene. The multilayer stretch film has a total number of layers greater than 3.

[7] In one embodiment, a multilayer stretch film comprises a first layer having a first surface and a second surface opposing the first surface, and a second layer disposed on the first surface of the first layer. The first layer is a core layer comprising graphene. The second layer is a slip layer comprising a first polymer resin.

[8] Various embodiments of the present disclose also provide oriented stretch films, for example, resulting from stretching the multilayer stretch films as disclosed herein. The oriented stretch films of the present disclosure maintain the desired physical properties (e.g., puncture resistance) of the multilayer stretch films.

[9] In one embodiment, the oriented stretch film comprises a first layer comprising a first polymer resin, a second layer comprising a polymer material, and a core layer disposed between the first layer and the second layer. The core layer comprises graphene. The oriented stretch film has a thickness in the range of about 4 pm to about 10 pm. BRIEF DESCRIPTION OF THE FIGURES

[10] Figure 1 is a schematic, cross-sectional view of one example embodiment of a portion of a multilayer stretch film according to the present disclosure.

[11] Figure 2 is a schematic, cross-sectional view of another example embodiment of a portion of a multilayer stretch film according to the present disclosure.

[12] Figure 3 is a schematic, cross-sectional view of another example embodiment of a portion of a multilayer stretch film according to the present disclosure.

[13] Figure 4 is a schematic diagram showing the water vapor transmission rates of multilayer stretch Film A and each of the comparative films.

[14] In the drawings, the thickness of the layers are exaggerated for clarity. Though the figures show variations of exemplary embodiments, these figures are not necessarily intended to be mutually exclusive from each other. Rather, as will be seen from the context of the detailed description below, certain features depicted and described in different figures can be combined with other features from other figures to result in various embodiments, when taking the figures and their description as a whole into consideration.

DETAILED DESCRIPTION

[15] Various embodiments of the present disclosure provide multilayer stretch films. As shown in the examples below, the multilayer stretch film as described herein provides a balance of beneficial properties compared to other laminated films. Some of these properties include clinginess, puncture resistance, load retention, and barrier performance. The multilayer stretch film as described herein can therefore perform at least as well as — and in many cases better than — other laminated films when used to wrap, unitize, or otherwise secure items. I. Multilayer Stretch Film

[16] Figure 1 is a schematic, cross-sectional view of one example embodiment of a portion of a multilayer stretch film 100 according to the present disclosure. As illustrated, the multilayer stretch film 100 includes a first layer 110, a second layer 120, and a core layer 130 disposed between the first layer 110 and the second layer 120.

[17] In this embodiment, the first layer 110 is a non-cling layer (e.g., a slip layer), and the second layer 120 is a cling layer. As described herein, the “cling” property of the film is generally defined as its cohesive bonding strength, e.g., its ability to bond to itself. This cling property allows the film to form a tight seal when the film is wrapped around an article or a collection of articles. Particularly, when the film is wrapped around the article(s), the first layer 110 of the film is located on the side of the film away from the article(s), and the second layer 120 of the film is located on the side of the film closest to the article(s), thereby firmly securing the article(s) for ease of transport or storage.

[18] In various embodiments, the first layer 110 includes a first polymer resin. In various embodiments, the first polymer resin is a low-density polyethylene resin (LDPE), a linear low-density polyethylene resin (LLDPE), or a combination thereof.

[19] The first layer 110 is designed to provide a smooth surface to allow the film to be easily wrapped around the article(s). This “non-cling” property of the first layer 110 also makes it easy to unwrap the film if so desired. Accordingly, in various embodiments, the first layer 110 has a coefficient of friction less than 1. For example, the coefficient of friction is in the range of 0.3 to 0.9, e.g., in the range of 0.3 to 0.8, or 0.3 to 0.7, or 0.3 to 0.6, or 0.3 to 0.5, or 0.3 to 0.4, or 0.4 to 0.9, or 0.4 to 0.8, or 0.4 to 0.7, or 0.4 to 0.6, or 0.4 to 0.5, or 0.5 to 0.9, or 0.5 to 0.8, or 0.5 to 0.7, or 0.5 to 0.6, or 0.6 to 0.9, or 0.6 to 0.8, or 0.6 to 0.7, or 0.7 to 0.9, or 0.7 to 0.8, or 0.8 to 0.9. [20] The second layer 120, on the other hand, includes a polymer material and is designed to provide a surface having more measurable cling to allow the film to tightly cling to itself and to the article(s) when wrapped around the article(s). This “cling” property of the second layer 120 allows the film to provide good load retention and ensures the film maintains its tightness to securely wrap or hold the article(s) during storage or transport.

[21] Accordingly, in various embodiments, the polymer material of the second layer 120 is a plastomer. The addition of a plastomer to the second layer 120 can provide greater cling to the film. In various embodiments, the plastomer is in an amount in the range of 95 % to 100 % by weight of the second layer 120, e.g., in the range of 95 % to 99 %, or 95 % to 98 %, or 95 % to 97 %, or 95 % to 96 %, or 96 % to 100 %, or 96 % to 99 %, or 96 % to 98 %, or 96 % to 97 %, or 97 % to 100 %, or 97 % to 99 %, or 97 % to 98 %, or 98 % to 100 %, or 98 % to 99 %, or 99 % to 100 %. In various embodiments, the plastomer is a polyolefin plastomer comprising ethylene copolymerized with at least one C3-C10 a-olefin, such as a C4 a-olefin, a Ce a-olefin, a Cs a-olefin (e.g., 1-octene), or a C₆ a-metallocene.

[22] To improve the processibility of the plastomer, the second layer 120 also includes a process aid. In various embodiments, the process aid is in an amount in the range of 0.1 % to 2 % by weight of the second layer 120, e.g., in the range of 0.1 % to 1.8 %, or 0.1 % to 1.5 %, or 0.1 % to 1.2 %, or 0.1 % to 1 %, or 0.5% to 2 %, or 0.5 % to 1.8 %, or 0.5 % to 1.5 %, or 0.5 % to 1.2 %, or 0.5 % to 1 %, or 0.8 % to 2 %, or 0.8 % to 1.8 %, or 0.8 % to 1.5 %, or 0.8 % to 1.2 %, or 0.8 % to 1 %. In various embodiments, the process aid is a fluoropolymer. In various other embodiments, the process aid is a fluoropolymer mixed with polyethylene glycol, tetrafluoroethylene, or a combination thereof.

[23] In various other embodiments, the polymer material of the second layer 120 is an elastomer. Incorporation of an elastomer into the second layer 120 can provide the softness or flexibility for the film. In various embodiments, the elastomer is in an amount in the range of 95 % to 100 % by weight of the second layer 120, e.g., in the range of 95 % to 99 %, or 95 % to 98 %, or 95 % to 97 %, or 95 % to 96 %, or 96 % to 100 %, or 96 % to 99 %, or 96 % to 98 %, or 96 % to 97 %, or 97 % to 100 %, or 97 % to 99 %, or 97 % to 98 %, or 98 % to 100 %, or 98 % to 99 %, or 99 % to 100 %. In various embodiments, the elastomer is an ethylene-vinyl acetate (EVA) copolymer.

[24] In various embodiments, to modify the tackiness of the film, the second layer 120 further includes a C4-C10 based polymer. In various embodiments, the C4-C10 based polymer is in an amount in the range of 0.1 % to 5.0 % by weight of the second layer 120, e.g., in the range of 0.1 % to 4.5 %, or 0.1 % to 4.0 %, or 0.1 % to 3.5 %, or 0.1 % to 3.0 %, or 0.1 % to

2.5 %, or 0.1 % to 2.0 %, or 0.1 % to 1.5 %, or 0.1 % to 1.0 %, or 0.1 % to 0.5 %, or 0.5 % to

5.0 %, or 0.5 % to 4.5 %, or 0.5 % to 4.0 %, or 0.5 % to 3.5 %, or 0.5 % to 3.0 %, or 0.5 % to

2.5 %, or 0.5 % to 2.0 %, or 0.5 % to 1.5 %, or 1.0 % to 5.0 %, or 1.0 % to 4.5 %, or 1.0 % to

4.0 %, or 1.0 % to 3.5 %, or 1.0 % to 3.0 %, or 1.0 % to 2.5 %, or 1.0 % to 2.0 %, or 1.0 % to

1.5 %. In various embodiments, the C4-C10 based polymer is a polyisobutylene (PIB) polymer.

[25] In various embodiments, to protect the wrapped article(s) from corrosion (e.g., when the article(s) has a metal surface), the second layer 120 further includes a volatile corrosion inhibitor (VCI). The VCI is a chemical substance that vaporizes when the film comes into contact with a metal surface, thereby creating a protective atmosphere around the wrapped article(s) to protect the article(s) from rust and corrosion during storage or transport. In various embodiments, the VCI is in an amount in the range of 0.5 % to 2.0 % by weight of the second layer 120, e.g., in the range of 0.5 % to 1.8 %, or 0.5 % to 1.5 %, or 0.5 % to 1.2 %, or 0.5 % to 1.0 %, or 0.5 % to 0.8 %, or 0.8 % to 2.0 %, or 0.8 % to 1.5 %, or 0.8 % to 1.2

%, or 0.8 % to 1.0 %, 1.0 % to 2.0 %, or 1.0 % to 1.8 %, or 1.0 % to 1.5 %, or 1.0 % to 1.2 %, or 1.2 % to 2.0 %, or 1.2 % to 1.8 %, or 1.2 % to 1.5 %, or 1.5 % to 2.0 %, or 1.5 % to 1.8 %, or 1.8 % to 2.0 %. Further, in various embodiments, the VCI is in an amount in the range of 0.5 % to 5.0 % by weight of the second layer 120, e.g., in the range of 0.5 % to 4.5 %, or 0.5 % to 4.0 %, or 0.5 % to 3.5 %, or 0.5 % to 3.0 %, or 0.5 % to 2.5 %, or 0.5 % to 2.0 %, or

0.5 % to 1.5 %, or 0.5 % to 1.0 %, or 1.0 % to 4.5 %, or 1.0 % to 4.0 %, or 1.0 % to 3.5 %, or

1.0 % to 3.0 %, or 1.0 % to 2.5 %, or 1.0 % to 2.0 %, or 1.0 % to 1.5 %, or 1.5 % to 4.5 %, or

1.5 % to 4.0 %, or 1.5 % to 3.5 %, or 1.5 % to 3.0 %, or 1.5 % to 2.5 %, or 1.5 % to 2.0 %, or

2.0 % to 4.5 %, or 2.0 % to 4.0 %, or 2.0 % to 3.5 %, or 2.0 % to 3.0 %, or 2.0 % to 2.5 %, or

2.5 % to 4.5 %, or 2.5 % to 4.0 %, or 2.5 % to 3.5 %, or 2.5 % to 3.0 %, or 3.0 % to 4.5 %, or

3.0 % to 4.0 %, or 3.0 % to 3.5 %, or 3.5 % to 4.5 %, or 3.5 % to 4.0 %, or 4.0 % to 4.5 %.

[26] Although the first layer 110 is a non-cling layer, it can still exhibit a small amount of measurable cling. But the cling property exhibited by the first layer 110 are generally less than the cling properties exhibited by the second layer 120. As such, the cling force exhibited between two cling layers of adjacent film structures as disclosed herein is generally greater than the cling force exhibited between the cling layer of one film and the non-cling layer of another film.

[27] Accordingly, in various embodiments, the multilayer stretch film 100 exhibits a cling of at least 200 grams-force per inch, e.g., at least 205 grams-force per inch, or at least 210 grams-force per inch, or at least 215 grams-force per inch, or at least 220 grams-force per inch, as measured by ASTM D5458.

[28] Further, in various embodiments, the multilayer stretch film 100 exhibits a cling between the second layer 120 and the first layer 110 in the range of 5 to 100 grams-force per inch, e.g., in the range of 5 to 80 grams-force per inch, or 5 to 60 grams-force per inch, or 5 to 40 grams-force per inch, or 5 to 20 grams-force per inch, or 5 to 10 grams-force per inch, or 10 to 100 grams-force per inch, or 10 to 80 grams-force per inch, or 10 to 60 grams-force per inch, or 10 to 40 grams-force per inch, or 10 to 20 grams-force per inch, or 20 to 100 grams-force per inch, or 20 to 80 grams-force per inch, or 20 to 60 grams-force per inch, or 20 to 40 grams-force per inch, or 40 to 100 grams-force per inch, or 40 to 80 grams-force per inch, or 40 to 60 grams-force per inch, or 60 to 100 grams-force per inch, or 60 to 80 gramsforce per inch, or 80 to 100 grams-force per inch, as measured by ASTM D882 and ASTMD5458.

[29] Referring to Figure 1, the multilayer stretch film 100 includes a core layer 130 disposed between the first layer 110 and the second layer 120. As disclosed herein, the present inventors have determined that including graphene in the core layer 130 can significantly enhance the overall strength and durability of the film, yet without interfering with the cling and non-cling properties of the film. For example, the present inventors have determined that incorporating graphene to the core layer 130 can provide enhanced puncture resistance, barrier performance, and structural integrity to the film.

[30] As used herein, the term “graphene” refers to pure graphene or graphene derivatives. Specifically, pure graphene is a two-dimensional (2D) atomic crystal comprised of a single-atom thick (i.e., monolayer) honeycomb arrangement of carbon atoms bonded via sp² bonds. Graphene derivatives can be functionalized graphene, graphene oxides, or reduced graphene oxides. For example, functionalized graphene refers to pure graphene which has incorporated into the graphene lattice a variety of chemical functional groups (e.g., -OH, -COOH, or NH2). Graphene oxides, also known as graphitic oxides or graphitic acids, refer to compounds of carbon, oxygen, and hydrogen in variable ratios, obtained by treating graphite with strong oxidizers and/or acids. Reduced graphene oxides refer to graphene oxides that are processed to have a reduced oxygen content. [31] Accordingly, in various embodiments, the core layer 130 includes graphene in an amount in the range of 0.5 % to 10 % by weight thereof, e.g., in the range of 0.5 % to 9 %, or 0.5 % to 8 %, or 0.5 % to 7 %, or 0.5 % to 6 %, or 0.5 % to 5 %, or 0.5 % to 4 %, or 0.5 % to 3 %, or 0.5 % to 2 %, or 0.5 % to 1 %, or 1 % to 10 %, or 1 % to 9 %, or 1 % to 8 %, or 1 % to 7 %, or 1 % to 6 %, or 1 % to 5 %, or 1 % to 4 %, or 1 % to 3 %, or 1 % to 2 %.

[32] In various other desirable embodiments, the core layer 130 includes a plurality of individual layers, and each individual layer includes graphene as described herein. For example, each individual layer includes graphene in an amount in the range of 0.5 % to 10 % by weight thereof.

[33] The core layer 130 further includes a second polymer resin. In various embodiments, the second polymer resin is in an amount in the range of 90 % to 99.5 % by weight of the core layer 130, e.g., in the range of 90 % to 99 %, or 90 % to 98 %, or 90 % to 97 %, or 90 % to 96 %, or 90 % to 95 %, or 90 % to 94 %, or 90 % to 93 %, or 90 % to 92 %, or 90 % to 91 %. In various embodiments, the second polymer resin is a linear low-density polyethylene resin (LLDPE).

[34] A total thickness of the multilayer stretch film 100 can vary depending on a specific application of the film. In various embodiments, the total thickness of the multilayer stretch film 100 is 20 pm. In other various embodiments, the total thickness of the multilayer stretch film 100 is 30 pm. In other various embodiments, the total thickness of the multilayer stretch film 100 is 50 pm. In other various embodiments, the total thickness of the multilayer stretch film 100 is 60 pm. In other various embodiments, the total thickness of the multilayer stretch film 100 is 80 pm. [35] In various embodiments, the core layer 130 has a thickness of at least 70 % of a total thickness of the multilayer stretch film 100, e.g., at least 75 %, or at least 80 %, or at least 85 %, or at least 90 %, or at least 95 %.

[36] As noted above, the multilayer stretch film 100 can be stretched in response to an applied force. Accordingly, in various embodiments, the multilayer stretch film 100 can be stretched by more than 50 % of its original, unstretched length, e.g., by more than 80 %, or by more than 100 %, or by more than 120 %, or by more than 150 %, or by more than 200 %, as measured by ASTM D4649.

[37] In various embodiments, the multilayer stretch film 100 has a machine direction (MD) tear strength of at least 700 g, e.g., at least 750 g, or at least 800 g, as measured by ASTM DI 922. In various embodiments, the multilayer stretch film 100 has a tear direction (TD) tear strength of at least 1000 g, e.g., at least 1100 g, or at least 1200 g., as also measured by ASTM DI 922.

[38] In various embodiments, the multilayer stretch film 100 exhibits an impact resistance of at least 450 g, e.g., at least 500 g, or at least 550 g, as measured by ASTM D1709.

[39] In various embodiments, the multilayer stretch film 100 exhibits a puncture resistance of greater than 6 N, e.g., greater than 7 N, or greater than 8 N, or greater than 10 N, as measured by ASTM Fl 306.

[40] In various embodiments, the first layer 110 of the multilayer stretch film 100 has a surface energy in the range of 25 mN/m to 30 mN/m, e.g., in the range of 25 mN/m to 28 mN/m, or 26 mN/m to 30 mN/m, or 26 mN/m to 28 mN/m, or 28 mN/m to 30 mN/m, as measured by a mobile surface analyzer by Kruss Scientific. In various embodiments, the second layer 120 of the multilayer stretch film 100 has a surface energy in the range of 25 mN /m to 30 nM/m, e.g., in the range of 25 mN/m to 28 mN/m, or 26 mN/m to 30 mN/m, or 26 mN/m to 28 mN/m, or 28 mN/m to 30 mN/m, as measured by a mobile surface analyzer by Kruss Scientific.

[41] In various embodiments, the multilayer stretch film 100 has a water vapor transmission rate in the range of 60 g/m²/day to 140 g/m²/day, e.g., in the range of 60 g/m²/day to 120 g/m²/day, or 60 g/m²/day to 100 g/m²/day, or 60 g/m²/day to 80 g/m²/day, or 80 g/m²/day to 140 g/m²/day, or 80 g/m²/day to 120 g/m²/day, or 80 g/m²/day to 100 g/m²/day, or 100 g/m²/day to 140 g/m²/day, or 100 g/m²/day to 120 g/m²/day, or 120 g/m²/day to 140 g/m²/day, as measured by a WVTR permeation analyzer by Ametek Mocon.

[42] In various embodiments, the multilayer stretch film 100 has a surface resistivity up to 5.20 x 10¹⁵ Q/square, e.g., up to 5.00 x 10¹⁵ Q/square, as measured by ASTM D257-14.

[43] In various embodiments, the multilayer stretch film 100 has a volume resistivity in the range of 1.0 x 10¹⁷ Q»cm to 2.0 x 10¹⁷ Q»cm, e.g., in the range of 1.2 x 10¹⁷ Q»cm to 2.0 x 10¹⁷ Q»cm, or 1.4 x 10¹⁷ Q»cm to 2.0 x 10¹⁷ Q»cm, or 1.6 x 10¹⁷ Q»cm to 2.0 x 10¹⁷ Q»cm, or 1.8 x 10¹⁷ Q»cm to 2.0 x 10¹⁷ Q»cm, as measured by ASTM D257-14.

[44] To modify the cling and/or non-cling properties of the film, the multilayer stretch film as described herein can include more than one individual cling and/or non-cling layers disposed on the two opposing sides of the core layer. Figure 2 is a schematic, cross-sectional view of a portion of such an embodiment of a multilayer stretch film 200 according to the present disclosure. As illustrated, the multilayer stretch film 200 includes at least one first layers 210, at least one second layers 220, and a core layer 230 disposed between the at least one first layers 210 and the at least one second layers 220. As described herein, the at least one first layers 210 are non-cling layers, and the at least one second layers 220 are cling layers. Further, the core layer 230 includes graphene as disclosed herein. In this embodiment, the multilayer stretch film 200 has a total number of layers greater than 3, e.g., a total number of 4 layers, or a total number of 5 layers, or a total number of 6 layers, or a total number of 7 layers.

[45] Figure 3 is a schematic, cross-sectional view of another example embodiment of a portion of a multilayer stretch film 300 according to the present disclosure. As illustrated, the multilayer stretch film 300 includes a first layer 310 having a first surface 312 and a second surface 314 opposing the first surface 312. The first layer 310 is a core layer including graphene. The multilayer stretch film 300 also includes a second layer 320 disposed on the first surface 312 of the first layer 310. As disclosed herein, the second layer 320 is a noncling layer. In this embodiment, the multilayer stretch film 300 does not include a cling layer as above. The multilayer stretch film 300 can exhibit anti-static properties (e.g., prevent accumulation of ion and electronic charges). The multilayer stretch film 300 can be used to wrap electronics.

[46] The multilayer stretch film of the present disclosure can be fabricated by any film lamination and/or co-extrusion technique and using any blown or cast film extrusion and lamination equipment known in the art.

[47] The multilayer stretch films as disclosed herein can be stretched at the factory prior to delivery to end users. Accordingly, stretched films are films that are taken from rolls of film that have already been produced, stretched in a separate step or an in-line process, and re-wound onto the film rolls for later use. Such stretching prior to delivery to end users as described herein is different from stretching the multilayer stretch film at the time of use by an end user.

[48] Stretching can lengthen the film footage, which not only increases the rate at which loads can be wrapped, but also lowers packaging costs due to possible unstretched waste. In various embodiments, a stretched, multilayer stretch film has a stretch ratio in the range of about 1 : 1.5 to about 1 :4, e.g., in the range of about 1 : 1.5 to about 1 :3.5, or about 1: 1.5 to about 1 :3, or about 1 : 1.5 to about 1 :2.5, or about 1 : 1.5 to about 1 :2, or about 1 :2 to about 1 :4, or about 1 :2 to about 1 :3.5, or about 1 :2 or to about 1 :3, or about 1 :2 to about 1 :2.5, or about 1 :2.5 to about 1 :4, or about 1 :2.5 to about 1 :3.5, or about 1:2.5 to about 1 :3, or about 1 :3 to about 1 :4, or about 1 :3 to about 1 :3.5, or about 1:3.5 to about 1 :4. In some embodiments, the stretched, multilayer stretch film as described herein has a stretch ratio of about 1 :2, or about 1 :2.5, or about 1 :3, or about 1 :3.5. As used herein, the term “stretch ratio” means the ratio of the total film length before stretching to the total film length after stretching. For example, a stretch ratio of 1 :2 means that the multilayer stretch film is stretched to 200 % of its total film length before stretching.

[49] As noted above, the multilayer stretch film as disclosed herein comprises various polyethylenes. Stretching can orient the molecules in the film along a stretching direction (e.g., a machine direction or a tear direction). Accordingly, in some embodiments, a stretched film is also an oriented stretch film. In some embodiments, stretching occurs in two directions (e.g., in two orthogonal directions) to form a biaxially oriented stretch film. In some embodiments, stretching occurs in only one direction to form a mono-oriented or uniaxially oriented stretch film. The stretched film is relatively stiff for its thickness and has very little residual orientation or stretch remaining before the film fails (e.g., breaks) in the stretching direction. These characteristics are desirable because much less effort is required by end users to wrap or secure loads using these stretched films as compared to conventional handheld stretch films. In various embodiments, a stretch film that is not oriented is converted into an oriented stretch film by stretching the stretch film to about 150 % to about 400 % of the original film length to achieve a desired thickness. [50] Further, as a result of stretching, the gauge of the stretched film is thinner compared to an unstretched film. Often, thinner films are more prone to the introduction of surface defects and/or breaks. However, the present inventors have unexpectedly found that by incorporating a core layer including graphene between a non-cling layer and a cling layer, the multilayer stretch film as disclosed herein can be stretched to have a thin thickness while maintaining the physical properties (e.g., mechanical properties) of the film, and that the stretching does not interfere with the cling and non-cling properties of the film. The oriented films described herein can therefore perform the same as other oriented films while using less film material, which reduces the cost of the oriented film.

[51] In various embodiments, the stretched film has a thickness in the range of about 20 % to about 50 % of the total thickness of the multilayer stretch film before stretching, e.g., a thickness that is about 25 %, about 30 %, about 35 %, about 40 %, or about 45 % of the total thickness of the multilayer stretch film before stretching. In various embodiments, the total thickness of the multilayer stretch film is in the range of about 14 pm to about 50 pm. In various embodiments, the stretched film has a thickness in the range of about 4 pm to about 10 pm.

[52] In various embodiments, the stretched film exhibits a cling of at least 200 gramsforce per inch, e.g., at least 250 grams-force per inch, or at least 300 grams-force per inch, or at least 350 grams-force per inch, as measured by ASTM D5458.

[53] In various embodiments, the stretched film exhibits a cling between a cling layer and a non-cling layer in the range of 50 to 100 grams-force per inch, e.g., in the range of 60 to 100 grams-force per inch, or 70 to 100 grams-force per inch, or 80 to 100 grams-force per inch, or 60 to 80 grams-force per inch, or 70 to 80 grams-force per inch, as measured by

ASTM D5458. [54] Accordingly, by incorporating a core layer including graphene between a non-cling layer and a cling layer, the multilayer stretch film as disclosed herein provides a balanced set of desirable properties. Particularly, the present inventors have determined that including the graphene in the core layer can significantly enhance the mechanical strength and the barrier performance of the film without interfering with the cling and non-cling properties of the outside layers of the film, and the resulting film can provide superior physical protection to the article(s) so wrapped. In addition, the “non-cling” property of the film allows easy application of the film, and the cling layer ensures superior load retention. The present inventors have also determined that the presence of graphene in the core layer allows the multilayer stretch film to be stretched to a thin film while maintaining the physical properties of the film. This configuration of film structures makes the film suitable for a wide range of applications in various industries.

II. Examples

[55] Testing was performed on exemplary multilayer stretch films as disclosed herein. Table 1 lists two such multilayer stretch films, Film A and Film B. Notably, Film A includes 1% graphene in its core layer, and Film B includes 5% graphene in its core layer. Both films have a total thickness of 50 pm, with a thickness of the core layer of 38.5 pm for each film.

TABLE 1. Compositions of Film A and Film B

1. Puncture Resistance a. Multilayer Stretch Films

[56] Puncture resistance tests are to measure the ability of a material to withstand being ruptured by a probe when a force is applied to the material at a constant speed. Accordingly, to evaluate the puncture resistance of the multilayer stretch film as disclosed herein, the present inventors have performed the tests on Film A in line with ASTM F1306. For comparison, the present inventors have also performed the tests on two comparative laminated films, Film Cl and Film C2, under similar conditions. Film Cl is a commercially available film by PanaceaWrap, which includes a mixture of polyethylene terephthalate (PET), LDPE and LLDPE. Film C2 is a commercially available film by MetPro, which includes LDPE. Notably, neither Film Cl nor Film C2 includes graphene in their compositions. The following data are obtained:

TABLE 2. Forces to Break

TABLE 3. Compressive Displacements

[57] Table 2 shows that Film A requires a force of at least 6 N to break, as measured by ASTM F1306. Table 2 also shows that as the crosshead speed increases, the force to break Film A also increases. These are consistent with the data obtained for Films Cl and C2. Accordingly, without intending to be bound by theory, Table 2 suggests that the puncture resistance of Film A is at least comparable to that of Films Cl and C2.

[58] Further, Table 3 shows that Film A exhibits higher compressive displacements than Films Cl and C2. This indicates that to break Film A, the probe requires to penetrate at a longer distance for Film A than for Films Cl and C2.

[59] Taken together, the data suggests that the presence of graphene in its core layer makes Film A have a puncture resistance comparable to those of Films Cl and C2. b. Oriented Stretch Films

[60] To evaluate the puncture resistance of the stretched, multilayer stretch film as disclosed herein, the present inventors have performed puncture resistance tests on Film Pl in line with ASTM F1306. Film Pl contains graphene and has a thickness of 5.2 pm. As used herein, Film Pl is stretched Film A as described in Section II.1. a. Film Pl is a different specimen than the Film A tested in Section II.1.a. For comparison, the present inventors have also performed the tests under similar conditions on a comparative laminated film (“Film C7”). Film C7 is a commercially available film by Signode, which does not contain graphene in its composition and has a thickness of 6.6 pm. The following data are obtained at a crosshead speed of 50 mm/min:

TABLE 7. Forces to Break and Compressive Displacement

[61] Table 7 shows that Film Pl can withstand a force beyond 4 N, higher than the force required to break Film C7. This observation indicates that Film Pl has a greater puncture resistance than Film C3. The data also shows that Film Pl exhibits a higher compressive displacement than Film C7, suggesting that to break Film Pl, the probe needs to penetrate at a longer distance for Film Pl than for Film C7.

[62] Accordingly, without intending to be bound by theory, Table 7 shows that the presence of graphene in its core layer helps the stretched film maintain its mechanical strength, making the film more resistant to punctures than the film without graphene. 2, Water Vapor Transmission Rates

[63] Water vapor transmission rates (WVTR) are measured in grams per square meter per 24 hours (g/m²/day), and are considered to indicate the breathability of a material (i.e., the ability of the material to be permeable to water vapor). Accordingly, the present inventors have evaluated the WVTRs for Film A using a permeation analyzer by Ametek Mocon. For comparison, the present inventors have also measured the WVTRs for other comparative films, including Films C3, C4, C5, and C6, using the permeation analyzer by Ametek Mocon. Particularly, both Films C3 and C4 are multilayer stretch films like Film A, but unlike Film A, neither Film C3 nor Film C4 includes graphene in its core layer, and both Film C3 and Film C4 include elastomers, PIB polymers and VCIs in their cling layers. Film C5 is a commercially available film by Cleveland Cliffs, which includes PET but no graphene in its composition. Film C6 is a multilayer stretch film like Film A, but unlike Film A, Film C6 does not include graphene in its core layer. Table 4 lists the thickness of Film A and each of these comparative films for the WVTR measurements.

TABLE 4. Thicknesses of Film A and Comparative Films C3 to C6

[64] Figure 4 is a schematic diagram showing the water vapor transmission rates measured for Film A and each of the comparative films. As shown in Figure 4, Film A has a water vapor transmission rate in the range of 60 g/m²/day to 140 g/m²/day, which is much lower than that measured for Film C6 (i.e., Film A without graphene). Similar results can be seen for Films C3 and C4, both of which exhibit a higher WVTR than Film A. Figure 4 also shows that Film A’s WVTR is similar to that of Film C5.

[65] Accordingly, without intending to be bound by theory, the data indicates that the presence of graphene in Film A can prevent water vapor from passing the film. This makes Film A have an enhanced barrier performance compared to Film C6, C3, and C4, and Film A’s barrier performance is at least comparable to that of Film C5.

[66] Taken together, the data suggests that with the presence of graphene in its core layer, Film A exhibits an enhanced barrier performance than Film A without graphene (i.e., Film C6) and Films C3 and C4, and that the barrier performance of Film A is at least comparable to Film C5.

3, Surface/Volume Resistivity

[67] Surface resistivity is the resistance to leakage current along the surface of an insulating material. Volume resistivity is the resistance to leakage current through the body of an insulating material. The higher the surface/volume resistivity, the lower the leakage current and the less conductive the material is. Accordingly, to evaluate the surface/volume resistivity of the multilayer stretch film as disclosed herein, the present inventors have performed tests on Film B in line with ASTM D257-14. For comparison, the present inventors have also performed the tests on a commercial anti-static bag (“Control”). The anti-static bag does not include graphene. The following data were obtained: TABLE 5. Surface Resistivity

TABLE 6. Volume Resistivity

[68] Table 5 shows that Film B has a surface resistivity up to 5.20 x 10¹⁵ Q/square, which appears to be the same as the Control. Further, Table 6 shows that Film B exhibits a volume resistivity in the range of 1.2 x 10¹⁷ Q»cmto 1.6 x 10¹⁷ Q»cm, which is much higher than the Control. Accordingly, without intending to be bound by theory, the data suggests that including graphene in a multilayer stretch film can provide a film with a surface/volume resistivity at least comparable to a commercial anti-static bag.

4, Cling Properties

[69] To evaluate the cling properties of the stretched, multilayer stretch film as disclosed herein, the present inventors have measured the cling, both I/O and O/O, of Film P2 in line with ASTM D5458. As described herein, “cling I/O” means a cling between a cling layer and a non-cling layer of Film P2, and “cling O/O” means a cling between the cling layers of Film P2. Film P2 contains graphene and is a stretched film resulted from stretching Film A as described in Section II.1.a. Film P2 is a different specimen than the Film A tested in Section II.1. a. As used herein, Film A has a total thickness of 17 pm and a total film length of 4500 m before stretching. For comparison, the present inventors have also measured the cling of a comparative laminated film (“Film C8”). Film C8 is a commercially available film by Signode, which does not contain graphene in its composition, and has a total thickness of 6.82 pm. The following data are obtained: TABLE 8. Cling Properties

[70] As shown in Table 8, Film P2 is a stretched film resulting from stretching Film A to

250 %, 280 %, or 290 % of Film A’s total film length, and the resulting Film P2 has a thickness of 6.90 pm, 5.58 pm, or 5.10 pm, respectively. Particularly, when Film A is stretched to Film P2 having a thickness of 6.90 pm, the resulting Film P2 has a cling I/O of about 83.7 grams-force per inch, and a cling 0/0 of about 280 grams-force per inch, as measured by ASTM D5458, suggesting that Film P2 exhibits better cling and non-cling properties than Film C8. Similar results can be seen when Film A is stretched to Film P2 having a thickness of 5.58 and 5.10 pm, respectively 280 % and 290 % of its total film length.

[71] Accordingly, without intending to be bound by theory, these data suggest that the presence of graphene in the core layer does not interfere with the cling and non-cling properties of the film, even when the film is stretched. III. CONCLUSION

[72] Thus, in various embodiments, the present disclosure provides a multilayer stretch film. The multilayer stretch film includes a first layer comprising a first polymer resin, a second layer comprising a polymer material, and a core layer disposed between the first layer and the second layer. The core layer comprises graphene.

[73] In various such embodiments of the multilayer stretch film, the first polymer resin is a low-density polyethylene resin.

[74] In various such embodiments of the multilayer stretch film, the first polymer resin is a linear low-density polyethylene resin.

[75] In various such embodiments of the multilayer stretch film, the first layer is a slip layer having a coefficient of friction in the range of 0.3 to 0.9.

[76] In various such embodiments of the multilayer stretch film, the polymer material of the second layer is a plastomer.

[77] In various such embodiments of the multilayer stretch film, the plastomer is a polyolefin plastomer comprising ethylene copolymerized with at least one C3-C10 a-olefin.

[78] In various such embodiments of the multilayer stretch film, the at least one C3-C10 a-olefin is a C4 a-olefin, a Ce a-olefin, a Cs a-olefin, or a C₆ a-metallocene.

[79] In various such embodiments of the multilayer stretch film, the plastomer is in an amount in the range of 95 % to 100 % by weight of the second layer.

[80] In various such embodiments of the multilayer stretch film, the second layer further comprises a process aid. [81] In various such embodiments of the multilayer stretch film, the process aid is a fluoropolymer.

[82] In various such embodiments of the multilayer stretch film, the process aid is a fluoropolymer mixed with polyethylene glycol, tetrafluoroethylene, or a combination thereof.

[83] In various such embodiments of the multilayer stretch film, the process aid is in an amount in the range of 0.1 % to 2 % by weight of the second layer.

[84] In various such embodiments of the multilayer stretch film, the process aid is in an amount in the range of 0.5 % to 1.5 % by weight of the second layer.

[85] In various such embodiments of the multilayer stretch film, the process aid is in an amount in the range of 0.8 % to 1.2 % by weight of the second layer.

[86] In various such embodiments of the multilayer stretch film, the polymer material of the second layer is an elastomer.

[87] In various such embodiments of the multilayer stretch film, the elastomer is an ethylene-vinyl acetate (EVA) copolymer.

[88] In various such embodiments of the multilayer stretch film, the elastomer is in an amount in the range of 95 % to 100 % by weight of the second layer.

[89] In various such embodiments of the multilayer stretch film, the second layer further comprises a C4-C10 based polymer.

[90] In various such embodiments of the multilayer stretch film, the C4-C10 based polymer is a polyisobutylene (PIB) polymer.

[91] In various such embodiments of the multilayer stretch film, the C4-C10 based polymer is in an amount in the range of 0.1 % to 5 % by weight of the second layer. [92] In various such embodiments of the multilayer stretch film, the second layer further comprises a volatile corrosion inhibitor (VCI).

[93] In various such embodiments of the multilayer stretch film, the VCI is in an amount in the range of 0.5 % to 2.0 % by weight of the second layer.

[94] In various such embodiments of the multilayer stretch film, the VCI is in an amount in the range of 0.5 % to 5.0 % by weight of the second layer.

[95] In various such embodiments of the multilayer stretch film, the multilayer stretch film has a cling of at least 200 grams-force per inch as measured by ASTM D5458.

[96] In various such embodiments of the multilayer stretch film, the multilayer stretch film has a cling between the second layer and the first layer in the range of 5 to 100 gramsforce per inch as measured by ASTM D5458.

[97] In various such embodiments of the multilayer stretch film, the graphene is in an amount in the range of 0.5 % to 10 % by weight of the core layer.

[98] In various such embodiments of the multilayer stretch film, the graphene is in an amount in the range of 1 % to 10 % by weight of the core layer.

[99] In various such embodiments of the multilayer stretch film, the graphene is in an amount in the range of 1 % to 5 % by weight of the core layer.

[100] In various such embodiments of the multilayer stretch film, the core layer comprises a plurality of individual layers, and each individual layer comprises graphene in an amount in the range of 0.5 % to 10 % by weight thereof.

[101] In various such embodiments of the multilayer stretch film, the core layer further comprises a second polymer resin. [102] In various such embodiments of the multilayer stretch film, the second polymer resin is a linear low-density polyethylene resin.

[103] In various such embodiments of the multilayer stretch film, the core layer has a thickness of at least 70 % of a total thickness of the multilayer stretch film.

[104] In various such embodiments of the multilayer stretch film, the multilayer stretch film has a machine direction tear strength of at least 700 g as measured by ASTM DI 922.

[105] In various such embodiments of the multilayer stretch film, the multilayer stretch film has a tear direction tear strength of at least 1000 g as measured by ASTM DI 922.

[106] In various such embodiments of the multilayer stretch film, the multilayer stretch film has an impact resistance of at least 450 g as measured by ASTM DI 709.

[107] In various such embodiments of the multilayer stretch film, the multilayer stretch film has a puncture resistance of greater than 6 N as measured by ASTM Fl 306.

[108] In various such embodiments of the multilayer stretch film, the first layer has a surface energy in the range of 25 mN/m to 30 mN/m.

[109] In various such embodiments of the multilayer stretch film, the second layer has a surface energy in the range of 25 mN/m to 30 mN/m.

[HO] In various such embodiments of the multilayer stretch film, the multilayer stretch film has a water vapor transmission rate in the range of 60 g/m²/day to 140 g/m²/day.

[Hl] In various such embodiments of the multilayer stretch film, the multilayer stretch film has a surface resistivity up to 5.20 x 10¹⁵ Q/square as measured by ASTM D257-14. [112] In various such embodiments of the multilayer stretch film, the multilayer stretch film has a volume resistivity in the range of 1.0 * 10¹⁷ Q»cm to 2.0 x 10¹⁷ Q»cm as measured by ASTM D257-14.

[113] In various other embodiments, the disclosure further provides a multilayer stretch film. The multilayer stretch film includes at least one first layers, at least one second layers, and a core layer disposed between the at least one first layers and the at least one second layers. Each of the at least one first layers comprises a first polymer resin. Each of the at least one second layers comprises a polymer material. The core layer comprises graphene. The multilayer stretch film has a total number of layers greater than 3.

[114] In various such embodiments of the multilayer stretch film, the total number of layers of the multilayer stretch film is between 4 and 7.

[115] In various such embodiments of the multilayer stretch film, the graphene is in an amount in the range of 0.5 % to 10 % by weight of the core layer.

[116] In various such embodiments of the multilayer stretch film, the core layer comprises a plurality of individual layers, and each individual layer comprises graphene in an amount in the range of 0.5 % to 10 % by weight thereof.

[117] In various other embodiments, the disclosure further provides a multilayer stretch film. The multilayer stretch film includes a first layer having a first surface and a second surface opposing the first surface, and a second layer disposed on the first surface of the first layer. The first layer is a core layer comprising graphene. The second layer is a slip layer comprising a first polymer resin.

[118] In various such embodiments of the multilayer stretch film, the graphene is in an amount in the range of 0.5 % to 10 % by weight of the first layer. [119] Further, in various embodiments, the present disclosure provides an oriented stretch film resulted. The oriented stretch film includes a first layer comprising a first polymer resin, a second layer comprising a polymer material, and a core layer disposed between the first layer and the second layer. The core layer comprises graphene. The oriented stretch film has a thickness in the range of about 4 pm to about 10 pm. In various such embodiments of the oriented stretch film, the oriented stretch film is a stretched film resulting from stretching a multilayer stretch film as disclosed herein so as to orient molecules in the film along a stretching direction.

[120] In various such embodiments of the oriented stretch film, the multilayer stretch film has a total thickness in the range of about 14 pm to about 50 pm.

[121] In various such embodiments of the oriented stretch film, the first polymer resin in the first layer of the oriented stretch film is a low-density polyethylene resin or a linear low- density polyethylene resin.

[122] In various such embodiments of the oriented stretch film, the polymer material in the second layer of the oriented stretch film is a plastomer as disclosed herein.

[123] In various such embodiments of the oriented stretch film, the graphene in the core layer of the oriented stretch film is in an amount in the range of 0.5 % to 10 % by weight of the core layer.

[124] In various such embodiments of the oriented stretch film, the oriented stretch film has a stretch ratio in the range of about 1 : 1.5 to about 1 :4.

[125] In various such embodiments of the oriented stretch film, the oriented stretch film has a stretch ratio in the range of about 1 : 1.5 to about 1 :3. [126] In various such embodiments of the oriented stretch film, the oriented stretch film has a stretch ratio of about 1:2.

[127] In various such embodiments of the oriented stretch film, the oriented stretch film has a stretch ratio of about 1 :2.5.

[128] In various such embodiments of the oriented stretch film, the oriented stretch film has a stretch ratio of about 1 :3.

[129] In various such embodiments of the oriented stretch film, the oriented stretch film is a biaxially oriented stretch film.

[130] In various such embodiments of the oriented stretch film, the oriented stretch film is a mono-oriented or uniaxially oriented stretch film.

[131] In various such embodiments of the oriented stretch film, the oriented stretch film has a cling of at least 250 grams-force per inch as measured by ASTM D5458.

[132] In various such embodiments of the oriented stretch film, the oriented stretch film has a cling between the second layer and the first layer in the range of 50 to 100 grams-force per inch as measured by ASTM D5458.

[133] Various changes and modifications to the above-described embodiments described herein will be apparent to those skilled in the art. These changes and modifications can be made without departing from the spirit and scope of this present subject matter and without diminishing its intended advantages. Not all of the depicted components described in this disclosure may be required, and some implementations may include additional, different, or fewer components from those expressly described in this disclosure. Variations in the arrangement and type of the components; the shapes, sizes, and materials of the components; and the manners of attachment and connections of the components may be made without departing from the spirit or scope of the claims as set forth herein. Also, unless otherwise indicated, any directions referred to herein reflect the orientations of the components shown in the corresponding drawings and do not limit the scope of the present disclosure. This specification is intended to be taken as a whole and interpreted in accordance with the principles of the invention as taught herein and understood by one of ordinary skill in the art.

Claims

1. A multilayer stretch film comprising: a first layer comprising a first polymer resin; a second layer comprising a polymer material; and a core layer disposed between the first layer and the second layer, wherein the core layer comprises graphene.

2. The multilayer stretch film of claim 1, wherein the first polymer resin is a low- density polyethylene resin.

3. The multilayer stretch film of claim 1, wherein the first polymer resin is a linear low-density polyethylene resin.

4. The multilayer stretch film of any of claims 1 to 3, wherein the first layer is a slip layer having a coefficient of friction in the range of 0.3 to 0.9.

5. The multilayer stretch film of any of claims 1 to 4, wherein the polymer material of the second layer is a plastomer.

6. The multilayer stretch film of claim 5, wherein the plastomer is a polyolefin plastomer comprising ethylene copolymerized with at least one C3-C10 a-olefin.

7. The multilayer stretch film of claim 6, wherein the at least one C3-C10 a-olefin is a C4 a-olefin, a Ce a-olefin, a Cs a-olefin, or a C₆ a-metallocene.

8. The multilayer stretch film of any of claims 5 to 7, wherein the plastomer is in an amount in the range of 95 % to 100 % by weight of the second layer.

9. The multilayer stretch film of any of claims 5 to 8, wherein the second layer further comprises a process aid.

10. The multilayer stretch film of claim 9, wherein the process aid is a fluoropolymer.

11. The multilayer stretch film of claim 9, wherein the process aid is a fluropolymer mixed with polyethylene glycol, tetrafluoroethylene, or a combination thereof.

12. The multilayer stretch film of any of claims 9 to 11, wherein the process aid is in an amount in the range of 0.1 % to 2 % by weight of the second layer.

13. The multilayer stretch film of any of claims 9 to 11, wherein the process aid is in an amount in the range of 0.5 % to 1.5 % by weight of the second layer.

14. The multilayer stretch film of any of claims 9 to 11, wherein the process aid is in an amount in the range of 0.8 % to 1.2 % by weight of the second layer.

15. The multilayer stretch film of any of claims 1 to 4, wherein the polymer material of the second layer is an elastomer.

16. The multilayer stretch film of claim 15, wherein the elastomer is an ethylenevinyl acetate (EVA) copolymer.

17. The multilayer stretch film of claim 15 or claim 16, wherein the elastomer is in an amount in the range of 95 % to 100 % by weight of the second layer.

18. The multilayer stretch film of any of claims 1 to 17, wherein the second layer further comprises a C4-C10 based polymer.

19. The multilayer stretch film of claim 18, wherein the C4-C10 based polymer is a polyisobutylene (PIB) polymer.

20. The multilayer stretch film of claim 18 or claim 19, wherein the C4-C10 based polymer is in an amount in the range of 0.1 % to 5 % by weight of the second layer.

21. The multilayer stretch film of any of claims 1 to 20, wherein the second layer further comprises a volatile corrosion inhibitor (VCI).

22. The multilayer stretch film of claim 21, wherein the VCI is in an amount in the range of 0.5 % to 2.0 % by weight of the second layer.

23. The multilayer stretch film of claim 21, wherein the VCI is in an amount in the range of 0.5 % to 5.0 % by weight of the second layer.

24. The multilayer stretch film of any of claims 1 to 23, wherein the multilayer stretch film has a cling of at least 200 grams-force per inch as measured by ASTM D5458.

25. The multilayer stretch film of any of claims 1 to 24, wherein the multilayer stretch film has a cling between the second layer and the first layer in the range of 5 to 100 grams-force per inch as measured by ASTM D5458.

26. The multilayer stretch film of any of claims 1 to 25, wherein the graphene is in an amount in the range of 0.5 % to 10 % by weight of the core layer.

27. The multilayer stretch film of any of claims 1 to 25, wherein the graphene is in an amount in the range of 1 % to 10 % by weight of the core layer.

28. The multilayer stretch film of any of claims 1 to 25, wherein the graphene is in an amount in the range of 1 % to 5 % by weight of the core layer.

29. The multilayer stretch film of any of claims 1 to 28, wherein the core layer comprises a plurality of individual layers, and each individual layer comprises graphene in an amount in the range of 0.5 % to 10 % by weight thereof.

30. The multilayer stretch film of any of claims 1 to 29, wherein the core layer further comprises a second polymer resin.

31. The multilayer stretch film of claim 30, wherein the second polymer resin is a linear low-density polyethylene resin.

32. The multilayer stretch film of any of claims 1 to 31, wherein the core layer has a thickness of at least 70 % of a total thickness of the multilayer stretch film.

33. The multilayer stretch film of any of claims 1 to 32, wherein the multilayer stretch film has a machine direction tear strength of at least 700 g as measured by ASTM DI 922.

34. The multilayer stretch film of any of claims 1 to 33, wherein the multilayer stretch film has a tear direction tear strength of at least 1000 g as measured by ASTM DI 922.

35. The multilayer stretch film of any of claims 1 to 34, wherein the multilayer stretch film has an impact resistance of at least 450 g as measured by ASTM DI 709.

36. The multilayer stretch film of any of claims 1 to 35, wherein the multilayer stretch film has a puncture resistance of greater than 6 N as measured by ASTM F1306.

37. The multilayer stretch film of any of claims 1 to 36, wherein the first layer has a surface energy in the range of 25 mN/m to 30 mN/m.

38. The multilayer stretch film of any of claims 1 to 37, wherein the second layer has a surface energy in the range of 25 mN/m to 30 mN/m.

39. The multilayer stretch film of any of claims 1 to 38, wherein the multilayer stretch film has a water vapor transmission rate in the range of 60 g/m²/day to 140 g/m²/day.

40. The multilayer stretch film of any of claims 1 to 39, wherein the multilayer stretch film has a surface resistivity up to 5.20 x 10¹⁵ Q/square as measured by ASTM D257- 14.

41. The multilayer stretch film of any of claims 1 to 40, wherein the multilayer stretch film has a volume resistivity in the range of 1.0 x 10¹⁷ Q»cm to 2.0 x 10¹⁷ Q»cm as measured by ASTM D257-14.

42. A multilayer stretch film comprising: at least one first layers, wherein each of the at least one first layers comprises a first polymer resin; at least one second layers, wherein each of the at least one second layers comprises a polymer material; and a core layer disposed between the at least one first layers and the at least one second layers, wherein the core layer comprises graphene; and wherein the multilayer stretch film has a total number of layers greater than 3.

43. The multilayer stretch film of claim 42, wherein the total number of layers of the multilayer stretch film is between 4 and 7.

44. The multilayer stretch film of claim 42 or claim 43, wherein the graphene is in an amount in the range of 0.5 % to 10 % by weight of the core layer.

45. The multilayer stretch film of any of claims 42 to 44, wherein the core layer comprises a plurality of individual layers, and each individual layer comprises graphene in an amount in the range of 0.5 % to 10 % by weight thereof.

46. A multilayer stretch film comprising: a first layer having a first surface and a second surface opposing the first surface, wherein the first layer is a core layer comprising graphene; and a second layer disposed on the first surface of the first layer, wherein the second layer is a slip layer comprising a first polymer resin.

47. The multilayer stretch film of claim 46, wherein the graphene is in an amount in the range of 0.5 % to 10 % by weight of the first layer.

48. An oriented stretch film comprising: a first layer comprising a first polymer resin; a second layer comprising a polymer material; and a core layer disposed between the first layer and the second layer, wherein the core layer comprises graphene, wherein the oriented stretch film has a thickness in the range of about 4 pm to about 10 pm.

49. The oriented stretch film of claim 48, wherein the oriented stretch film is a stretched film resulting from stretching a multilayer stretch film so as to orient molecules in the film along a stretching direction.

50. The oriented stretch film of claim 49, wherein the multilayer stretch film has a total thickness in the range of about 14 pm to about 50 pm.

51. The oriented stretch film of claim 48, wherein the first polymer resin in the first layer of the oriented stretch film is a low-density polyethylene resin or a linear low- density polyethylene resin.

52. The oriented stretch film of claim 48 or claim 51, wherein the polymer material in the second layer of the oriented stretch film is a plastomer.

53. The oriented stretch film of any of claims 48 and 51-52, wherein the graphene in the core layer of the oriented stretch film is in an amount in the range of 0.5 % to 10 % by weight of the core layer.

54. The oriented stretch film of any of claims 48 and 51-53, wherein the oriented stretch film has a stretch ratio in the range of about 1 : 1.5 to about 1 :4.

55. The oriented stretch film of any of claims 48 and 51-53, wherein the oriented stretch film has a stretch ratio in the range of about 1 : 1.5 to about 1 :3.

56. The oriented stretch film of any of claims 48 and 51-53, wherein the oriented stretch film has a stretch ratio of about 1 :2.

57. The oriented stretch film of any of claims 48 and 51-53, wherein the oriented stretch film has a stretch ratio of about 1 :2.5.

58. The oriented stretch film of any of claims 48 and 51-53, wherein the oriented stretch film has a stretch ratio of about 1 :3.

59. The oriented stretch film of any of claims 48 and 51-58, wherein the oriented stretch film is a biaxially oriented stretch film.

60. The oriented stretch film of any of claims 48 and 51-58, wherein the oriented stretch film is a mono-oriented or uniaxially oriented stretch film.

61. The multilayer stretch film of any of claims 48 and 51-60, wherein the oriented stretch film has a cling of at least 250 grams-force per inch as measured by ASTM D5458.

62. The multilayer stretch film of any of claims 48 and 51-61, wherein the oriented stretch film has a cling between the second layer and the first layer in the range of 50 to 100 grams-force per inch as measured by ASTM D5458.