Cotton baling film with excellent toughness

Abstract

The present invention relates to the technical field of packaging materials, and particularly to a cotton packing film with excellent toughness. Specifically, the present invention relates to a non-sticky film for cotton packing film, wherein the non-sticky film has a configuration of A / B / C / D / E, the A layer is in contact with the sticky film and the E layer is in contact with the cotton, and each of the layers A, B, C, D and E contains a first metallocene polyethylene, a second metallocene polyethylene, low density polyethylene, high density polyethylene and / or linear low density polyethylene. The present invention achieves excellent toughness and tear resistance by defining the specific contents and their combinations of the first metallocene polyethylene, the second metallocene polyethylene, low density polyethylene, high density polyethylene and linear low density polyethylene in each of the layers A, B, C, D and E.

Description

Technical Field

[0001] The present invention relates to the technical field of packaging materials, and particularly relates to a cotton packing film with excellent toughness. Background Art

[0002] Cotton is one of the most important crops in the world. Cotton packing films are mainly used for packing cotton. Currently, the picking of cotton has mostly been mechanized. For example, cotton pickers are used. In order to prevent cotton from being secondarily polluted during the process from picking to the drying yard and to facilitate the subsequent handling of cotton, these cotton pickers require cotton packing films to pack a large amount of cotton and pack it into a cylindrical shape.

[0003] Generally, cotton packing films include non - sticky films and sticky films. During the operation of the cotton picker, the cotton is finally packed by winding the film. Each packing section of the film wound on the reel includes a non - sticky film and a sticky film. When packing cotton, first wind with the non - sticky film; then wind with the sticky film, and the number of winding turns is determined according to the diameter of the cotton bale (usually 1 - 2 turns), and finally the cotton packing is completed.

[0004] Cotton packing films require outstanding toughness, especially tear resistance, to prevent crack propagation in the cotton packing film during cotton picking and packing. Generally, a formulation based on Exceed TM XP 6026 is used to produce high - end cotton packing films. However, longitudinal (MD) tearing has always been a pain point for end - users: once the packing film is scratched or cut during cotton picking and packing due to sharp branches mixed in the cotton or external forces, etc., the crack is likely to propagate along the longitudinal (MD) direction on the surface of the packing film. In addition, during the unwinding process of the cotton packing film on the cotton picker, if a crack forms, the crack propagates along the longitudinal (MD) or transverse (TD) direction, which may cause the machine to jam and even lead to shutdown, thus requiring reinstalling the film roll.

[0005] There is a need in the art for a cotton packing film with excellent toughness, especially excellent tear resistance. Summary of the Invention

[0006] Cotton packing films usually contain sticky films and non - sticky films.

[0007] The present invention relates to a non - sticky film with excellent toughness, especially excellent tear resistance.

[0008] The tear resistance of the film can be characterized, for example, by the Elmendorf tear resistance in the transverse (TD) and / or longitudinal (MD) directions. Compared with the transverse (TD) Elmendorf tear resistance, the longitudinal (MD) Elmendorf tear resistance of the film is usually more difficult to improve.

[0009] The non-sticky film for cotton bale wrapping disclosed by the present invention unexpectedly has excellent tear resistance, especially excellent tear resistance in the machine direction (MD).

[0010] The currently available non-sticky films for cotton bale wrapping based on Exceed TM XP 6026 typically have a TD Elmendorf tear of approximately 19.0 g / μm. However, the non-sticky film for cotton bale wrapping disclosed by the present invention has a TD Elmendorf tear greater than about 19.0 g / μm, such as greater than or equal to about 19.5 g / μm, such as greater than or equal to about 20.0 g / μm, such as greater than or equal to about 20.5 g / μm, such as greater than or equal to about 21.0 g / μm, such as greater than or equal to about 21.5 g / μm, such as greater than or equal to about 22.0 g / μm, such as greater than or equal to about 22.5 g / μm, such as greater than or equal to about 23.0 g / μm, such as greater than or equal to about 23.5 g / μm, such as greater than or equal to about 24.0 g / μm, where the TD Elmendorf tear is determined according to the ASTM D1922-09 test method. The non-sticky film for cotton bale wrapping disclosed by the present invention has a TD Elmendorf tear less than or equal to about 25.0 g / μm, where the TD Elmendorf tear is determined according to the ASTM D1922-09 test method. The explicitly disclosed ranges include, but are not limited to, ranges formed by any combination of the values listed above, such as a TD Elmendorf tear greater than about 19.0 g / μm to about 25.0 g / μm, such as about 20.0 g / μm to about 25.0 g / μm.

[0011] The currently available non-sticky films for cotton bale wrapping based on Exceed TMThe non-sticky film for cotton bale wrapping of XP 6026 typically has an MD Elmendorf tear of approximately 5.0 g / μm. However, the non-sticky film for cotton bale wrapping disclosed in the present invention has an MD Elmendorf tear greater than about 5.0 g / μm, such as greater than or equal to about 5.5 g / μm, such as greater than or equal to about 6.0 g / μm, such as greater than or equal to about 6.1 g / μm, such as greater than or equal to about 6.5 g / μm, such as greater than or equal to about 7.0 g / μm, such as greater than or equal to about 8.0 g / μm, such as greater than or equal to about 9.0 g / μm, where the MD Elmendorf tear is determined according to the ASTM D1922-09 test method. The non-sticky film for cotton bale wrapping disclosed in the present invention has an MD Elmendorf tear less than or equal to about 10.0 g / μm, where the MD Elmendorf tear is determined according to the ASTM D1922-09 test method. The explicitly disclosed ranges include, but are not limited to, ranges formed by any combination of the numerical values listed above, such as an MD Elmendorf tear greater than about 5.0 g / μm to 10.0 g / μm, such as about 5.5 g / μm to 10.0 g / μm.

[0012] According to an embodiment of the present invention, the present invention relates to a non-sticky film for cotton bale wrapping, where the cotton bale wrapping film comprises a sticky film and a non-sticky film, and where the non-sticky film has a configuration of A / B / C / D / E, with the A layer in contact with the sticky film and the E layer in contact with the cotton.

[0013] Where each of the layers A, B, C, D, and E comprises (or consists essentially of, or consists of) a first metallocene polyethylene, a second metallocene polyethylene, low density polyethylene, high density polyethylene, and / or linear low density polyethylene, where the first metallocene polyethylene is BOCD polyethylene and the second metallocene polyethylene is not BOCD polyethylene;

[0014] The first metallocene polyethylene and the second metallocene polyethylene are not present in the A layer, the second metallocene polyethylene is present in each of the B, D, and E layers at a content of at least about 60 wt%, based on the weight of each of the B, D, and E layers, and the second metallocene polyethylene is present in the C layer at a content of at least about 20 wt%, based on the weight of the C layer.

[0015] Based on the total weight of the A, B, C, D, and E layers of the non-sticky film, the content of the first metallocene polyethylene is about 10 wt% - about 25 wt%.

[0016] Based on the total weight of the A, B, C, D, and E layers of the non-sticky film, the content of the second metallocene polyethylene is about 40 wt% - about 65 wt%.

[0017] Based on the total weight of the A, B, C, D, and E layers of the non-sticky film, the content of low-density polyethylene is about 10% by weight - about 20% by weight.

[0018] Based on the total weight of the A, B, C, D, and E layers of the non-sticky film, the content of high-density polyethylene is about 10% by weight - about 15% by weight.

[0019] Based on the total weight of the A, B, C, D, and E layers of the non-sticky film, the content of linear low-density polyethylene is about 2% by weight - about 10% by weight.

[0020] According to an embodiment of the present invention, the first metallocene polyethylene and the second metallocene polyethylene are not present in the A layer.

[0021] According to an embodiment of the present invention, the second metallocene polyethylene is present in each of the B, D, and E layers at a content of at least about 60% by weight, such as at least about 65% by weight, such as at least about 70% by weight, such as at least about 75% by weight, based on the weight of each of the B, D, and E layers.

[0022] According to an embodiment of the present invention, the second metallocene polyethylene is present in the C layer at a content of at least about 20% by weight, such as at least about 25% by weight, such as at least about 30% by weight, such as at least about 35% by weight, such as at least about 40% by weight, based on the weight of the C layer.

[0023] According to an embodiment of the present invention, based on the total weight of the A, B, C, D, and E layers of the non-sticky film, the content of the first metallocene polyethylene is about 10% by weight - about 25% by weight, such as about 13% by weight, such as about 15% by weight, such as about 20% by weight.

[0024] If the content of the first metallocene polyethylene in the non-sticky film is too low, the non-sticky film cannot achieve excellent tear resistance. If the content of the first metallocene polyethylene in the non-sticky film is too high, the non-sticky film is not stable enough during the production of blown films.

[0025] According to an embodiment of the present invention, based on the total weight of the A, B, C, D, and E layers of the non-sticky film, the content of the second metallocene polyethylene is about 40% by weight - about 65% by weight, such as about 45% by weight, such as about 51% by weight, such as about 55% by weight, such as about 60% by weight.

[0026] Based on the total weight of the A, B, C, D, and E layers of the non-sticky film, the content of low-density polyethylene is about 10% by weight - about 20% by weight, such as about 12% by weight, such as about 15% by weight, such as about 17% by weight, such as about 19% by weight.

[0027] According to an embodiment of the present invention, based on the total weight of layers A, B, C, D, and E of the non-stick film, the content of high-density polyethylene is from about 10 wt% to about 15 wt%, such as about 11 wt%, such as about 12 wt%, such as about 13 wt%, such as about 14 wt%.

[0028] According to an embodiment of the present invention, based on the total weight of layers A, B, C, D, and E of the non-stick film, the content of linear low-density polyethylene is from about 2 wt% to about 10 wt%, such as about 4 wt%, such as about 6 wt%, such as about 7 wt%, such as about 9 wt%.

[0029] According to an embodiment of the present invention, the first metallocene polyethylene is BOCD polyethylene, where the BOCD polyethylene contains from about 70 mol% to about 99 mol% of polymer units derived from ethylene, based on the total mole number of the polymer units of the BOCD polyethylene, and has a density of about 0.910 g / cm 3 to about 0.920 g / cm 3 , which is measured according to ASTM D-792 or ASTM D-1505, and a melt index (MI, or I 2.16 ) of from about 0.1 g / 10 min to about 1.0 g / 10 min, which is measured according to ASTM D-1238-E (190 °C / 2.16 kg), and the first metallocene polyethylene has a composition distribution breadth index (CDBI) of from about 20 wt% to about 55 wt%.

[0030] According to an embodiment of the present invention, the second metallocene polyethylene is not BOCD polyethylene. The second metallocene polyethylene contains from about 70 mol% to about 99 mol% of polymer units derived from ethylene, based on the total mole number of the polymer units of the second metallocene polyethylene, and has a density of about 0.910 g / cm 3 to about 0.920 g / cm 3 , which is measured according to ASTM D-792 or ASTM D-1505, and a melt index (MI, or I 2.16 ) of from about 0.1 g / 10 min to about 1.0 g / 10 min, which is measured according to ASTM D-1238-E (190 °C / 2.16 kg), and where the second metallocene polyethylene has a composition distribution breadth index (CDBI) of > 70 wt%.

[0031] According to an embodiment of the present invention, the low-density polyethylene (LDPE) has a density of from about 0.910 g / cm 3 to about 0.925 g / cm 3 , which is measured according to ASTM D-792 or ASTM D-1505.

[0032] According to an embodiment of the present invention, low density polyethylene (LDPE) has a melt index of greater than about 0.5 g / 10 min to less than about 2.0 g / 10 min, measured according to ASTM D-1238-E (190 °C / 2.16 kg).

[0033] According to an embodiment of the present invention, linear low density polyethylene (LLDPE) has a density of about 0.910 g / cm 3 to about 0.925 g / cm 3 and is measured according to ASTM D-792 or ASTM D-1505, where "linear" means that the polyethylene has no long chain branches or only has a small number of long chain branches.

[0034] According to an embodiment of the present invention, linear low density polyethylene (LLDPE) has a melt index of greater than about 0.5 g / 10 min to less than about 2.0 g / 10 min, measured according to ASTM D-1238-E (190 °C / 2.16 kg).

[0035] According to an embodiment of the present invention, high density polyethylene (HDPE) has a density greater than about 0.950 g / cm 3 and is measured according to ASTM D-792 or ASTM D-1505.

[0036] According to an embodiment of the present invention, high density polyethylene (HDPE) has a melt index of greater than about 0.5 g / 10 min to less than about 2.0 g / 10 min, measured according to ASTM D-1238-E (190 °C / 2.16 kg).

[0037] According to an embodiment of the present invention, the present invention provides a non-sticky film for cotton baling film, wherein the cotton baling film comprises a sticky film and a non-sticky film, wherein the non-sticky film has a configuration of A / B / C / D / E, the A layer is in contact with the sticky film and the E layer is in contact with the cotton,

[0038] wherein each of the layers A, B, C, D and E comprises a first metallocene polyethylene, a second metallocene polyethylene, low density polyethylene, high density polyethylene and / or linear low density polyethylene, wherein the first metallocene polyethylene is BOCD polyethylene and the second metallocene polyethylene is not BOCD polyethylene;

[0039] The first metallocene polyethylene and the second metallocene polyethylene are not present in the A layer, the second metallocene polyethylene is present in each of the B, D, E layers at a content of at least about 60% by weight, based on the weight of each of the B, D, E layers, and the second metallocene polyethylene is present in the C layer at a content of at least about 20% by weight, based on the weight of the C layer,

[0040] Based on the total weight of layers A, B, C, D, and E of the non-sticky film, the content of the first metallocene polyethylene is about 10 wt% - about 25 wt%, wherein the first metallocene polyethylene contains about 70 mol% to about 99 mol% of polymer units derived from ethylene, based on the total molar number of the polymer units of the first metallocene polyethylene, and has a density of about 0.914 g / cm 3 , which is measured according to ASTM D-792, and a melt index (MI, or I 2.16 ) of about 0.80 g / 10 min, which is measured according to ASTM D-1238-E (190 °C / 2.16 kg), and the first metallocene polyethylene has a compositional distribution breadth index (CDBI) of about 43 wt%,

[0041] Based on the total weight of layers A, B, C, D, and E of the non-sticky film, the content of the second metallocene polyethylene is about 40 wt% - about 65 wt%, wherein the second metallocene polyethylene contains about 70 mol% to about 99 mol% of polymer units derived from ethylene, based on the total molar number of the polymer units of the second metallocene polyethylene, and has a density of about 0.916 g / cm 3 , which is measured according to ASTM D-792, and a melt index (MI, or I 2.16 ) of about 0.20 g / 10 min, which is measured according to ASTM D-1238-E (190 °C / 2.16 kg), and the second metallocene polyethylene has a compositional distribution breadth index (CDBI) of about 80 wt%,

[0042] Based on the total weight of layers A, B, C, D, and E of the non-sticky film, the content of low-density polyethylene is about 10 wt% - about 20 wt%, wherein the low-density polyethylene (LDPE) has a density of about 0.923 g / cm 3 , which is measured according to ASTM D-1505, and a melt index of 0.75 g / 10 min, measured according to ASTM D-1238-E (190 °C / 2.16 kg),

[0043] Based on the total weight of layers A, B, C, D, and E of the non-sticky film, the content of high-density polyethylene is about 10 wt% - about 15 wt%, wherein the high-density polyethylene (HDPE) has a density of 0.961 g / cm 3 , which is measured according to ASTM D-1505, and a melt index of about 0.70 g / 10 min, measured according to ASTM D-1238-E (190 °C / 2.16 kg), and

[0044] Based on the total weight of layers A, B, C, D, and E of the non-stick film, the content of linear low-density polyethylene is about 2 wt% - about 10 wt%, where the linear low-density polyethylene (LLDPE) has a density of about 0.918 g / cm 3 and a melt index of about 1.0 g / 10 min, which are measured according to ASTM D-792 and ASTM D-1238-E (190 °C / 2.16 kg), respectively.

[0045] The thickness of the non-stick film of the present invention can be the common thickness in the art. According to an embodiment of the present invention, the non-stick film of the present invention can have a total thickness of 65.0 - 80.0 μm, for example, 75.0 μm.

[0046] According to an embodiment of the present invention, the non-stick film of the present invention has a configuration of A / B / C / D / E, where the thickness ratio of each layer A:B:C:D:E can be 1:b:c:d:1, where b is a number from 2 to 3, c is a number from 2 to 4, and d is a number from 2 to 3; the thickness ratio of each layer A:B:C:D:E is based on the thickness of layer A or layer E (i.e., the thicknesses of layer A and layer E are fixed at 1).

[0047] For example, for the non-stick film of the present invention, the thickness ratio of each layer A:B:C:D:E can be 1:2:3:3:1.

[0048] Metallocene polyethylene (mPE)

[0049] According to an embodiment of the present invention, the non-stick film for cotton bale wrapping contains a first metallocene polyethylene and a second metallocene polyethylene, where the metallocene polyethylene is a polyethylene homopolymer or a polyethylene copolymer prepared using a metallocene catalyst.

[0050] As used herein, the term "metallocene catalyst" is defined as containing at least one transition metal compound that contains one or more substituted or unsubstituted cyclopentadienyl moieties (Cp) (usually two Cp moieties) together with a Group 4, 5, or 6 transition metal of the periodic table such as zirconium, hafnium, and titanium.

[0051] The "metallocene catalyst" generally needs to be activated with a suitable cocatalyst or activator to produce an "active metallocene catalyst", that is, an organometallic complex having vacant coordination sites capable of coordinating, inserting, and polymerizing olefins. The active catalyst system generally contains not only the metallocene complex but also an activator, such as aluminoxane or its derivatives (preferably methylaluminoxane), an ionizing activator, a Lewis acid, or a combination thereof. Alkylaluminoxane (usually methylaluminoxane and modified methylaluminoxane) is particularly suitable as a catalyst activator. The catalyst system can be supported on a carrier, and the carrier is usually an inorganic oxide or chloride or a resin material, such as polyethylene or silica.

[0052] First metallocene polyethylene

[0053] According to an embodiment of the present invention, the non-sticky film for cotton baling film comprises a first metallocene polyethylene and a second metallocene polyethylene, wherein the first metallocene polyethylene is a broad orthogonal composition distribution (BOCD) polyethylene.

[0054] Broad orthogonal composition distribution (BOCD) polyethylene is a polyethylene homopolymer or a polyethylene copolymer, and in most cases is a polyethylene copolymer. It is desirable for the polyethylene to have a broad orthogonal composition distribution, and the broad orthogonal composition distribution provides an enhanced balance of stiffness, toughness, and processability (S / T / P) for the polyethylene and compositions containing these polymers. Considering that the polymer is a blend of molecules with different chain length distributions, the polymer with BOCD is a branched polymer, and any branching that occurs (if not all) predominantly on the high molecular weight molecules of the polymer makes them less crystalline. This microstructure has a tendency to improve certain properties of products made from the BOCD-type polymers (including the polyolefin compositions described herein).

[0055] Polyethylene produced by Ziegler-Natta ("ZN") tends not to have a BOCD-type structure, and most short chain branching occurs on the low molecular weight portion of the molecules produced in this way. On the other hand, some metallocene polyethylenes can typically have a BOCD-type structure. The value of BOCD polymers relative to conventional polymers is significant.

[0056] In an embodiment of the present invention, the BOCD polyethylene can have a "broad orthogonal composition distribution" ("BOCD"). The broad orthogonal composition distribution can be determined using fractionation techniques such as gel permeation chromatography-differential viscometer (GPC-DV), temperature rising elution fractionation-differential viscometer (TREF-DV), or cross-fractionation techniques. For example, WO 2015 / 123164A1 (which is incorporated herein by reference) discusses the TREF technique and provides a measurement of the bivariate mass distribution of the crystalline portion of BOCD polyethylene.

[0057] The BOCD polyethylene of the present invention comprises from about 70 mol% to about 99 mol% of units derived from ethylene, based on the total number of moles of polymer units of the BOCD polyethylene. Based on the total number of moles of polymer units of the BOCD polyethylene, the lower limit of the content range of units derived from ethylene can be 70 mol%, 75 mol%, 80 mol%, 85 mol%, 90 mol%, 92 mol%, 94 mol%, 95 mol%, 96 mol%, 97 mol%, 98 mol% or 99 mol%. Based on the total number of moles of polymer units of the BOCD polyethylene, the upper limit of the content range of units derived from ethylene can be 80 mol%, 85 mol%, 90 mol%, 92 mol%, 94 mol%, 95 mol%, 96 mol%, 97 mol%, 98 mol%, 99 mol%. Any one of the above upper limit contents can be combined with any one of the above upper limit contents; any one of the above upper limit contents can be combined with any one of the above lower limit contents; and any one of the above upper limit contents can be combined with any one of the above lower limit contents.

[0058] The BOCD polyethylene of the present invention may have polymer units derived from C3-C20 olefins, such as C3-C20 α-olefins, such as hexene or octene, that are equal to or less than 30 mol%. Based on the total number of moles of polymer units of the BOCD polyethylene, the upper limit of the content range of polymer units derived from C3-C20 olefins can be 30 mol%, 25 mol%, 20 mol%, 15 mol%, 10 mol%, 8 mol%, 6 mol%, 5 mol%, 4 mol%, 3 mol%, 2 mol%, 1 mol% or 0.5 mol%. Based on the total number of moles of polymer units of the BOCD polyethylene, the lower limit of the content range of polymer units derived from C3-C20 olefins can be 0 mol%, 1 mol%, 2 mol%, 3 mol%, 4 mol%, 5 mol%, 6 mol%, 8 mol%, 10 mol%, 15 mol%, 20 mol% or 25 mol%. Any one of the above upper limit contents can be combined with any one of the above upper limit contents; any one of the above upper limit contents can be combined with any one of the above lower limit contents; and any one of the above upper limit contents can be combined with any one of the above lower limit contents.

[0059] According to an embodiment of the present invention, the density of the BOCD polyethylene measured according to ASTM D-792 or ASTM D-1505 can be ≥ about 0.910 g / cm 3 , for example ≥ about 0.911 g / cm 3 , for example ≥ about 0.912 g / cm 3 , for example ≥ about 0.913 g / cm 3 , for example ≥ about 0.914 g / cm3 , such as ≥ about 0.915 g / cm 3 , such as ≥ about 0.916 g / cm 3 , such as ≥ about 0.917 g / cm 3 , such as ≥ about 0.918 g / cm 3 , such as ≥ about 0.919 g / cm 3 of density.

[0060] Additionally or alternatively, the density of the BOCD polyethylene measured according to ASTM D-792 or ASTM D-1505 can be ≤ about 0.920 g / cm 3 , such as ≤ about 0.919 g / cm 3 , such as ≤ about 0.918 g / cm 3 , such as ≤ about 0.917 g / cm 3 , such as ≤ about 0.916 g / cm 3 , such as ≤ about 0.915 g / cm 3 , such as ≤ about 0.914 g / cm 3 , such as ≤ about 0.913 g / cm 3 . The explicitly disclosed ranges include, but are not limited to, ranges formed by any combination of the values listed above, such as about 0.910 g / cm 3 - about 0.920 g / cm 3 , about 0.913 g / cm 3 - about 0.920 g / cm 3 , about 0.914 g / cm 3 - about 0.918 g / cm 3 , about 0.915 g / cm 3 - about 0.917 g / cm 3 etc.

[0061] According to an embodiment of the present invention, the melt index (MI, or I 2.16 ) of the BOCD polyethylene measured according to ASTM D-1238 (190 °C / 2.16 kg) can be ≥ about 0.1 g / 10 min, such as ≥ about 0.2 g / 10 min, such as ≥ about 0.3 g / 10 min, such as ≥ about 0.4 g / 10 min, such as ≥ about 0.5 g / 10 min, such as ≥ about 0.6 g / 10 min, such as ≥ about 0.7 g / 10 min, such as ≥ about 0.8 g / 10 min, such as ≥ about 0.9 g / 10 min.

[0062] Additionally or alternatively, the melt index (MI, or I 2.16)It can be ≤ about 1.0 g / 10 min, such as ≤ about 0.9 g / 10 min, such as ≤ about 0.8 g / 10 min, such as ≤ about 0.7 g / 10 min, such as ≤ about 0.6 g / 10 min, such as ≤ about 0.5 g / 10 min, such as ≤ about 0.4 g / 10 min, such as ≤ about 0.3 g / 10 min. The explicitly disclosed ranges include, but are not limited to, ranges formed by any combination of the values listed above, such as about 0.1 g / 10 min - about 1.0 g / 10 min, such as about 0.2 g / 10 min - about 0.9 g / 10 min.

[0063] The term "composition distribution breadth index (CDBI)" represents the weight percentage of copolymer molecules having a comonomer content within 50% of the median molar comonomer content of all the comonomers. As measured by the composition distribution breadth index (CDBI), the BOCD polyethylene of the present invention generally has a broad composition distribution.

[0064] The CDBI of a copolymer can be measured using techniques known in the art. The CDBI of a copolymer is readily determined using well-known techniques for separating individual fractions of a copolymer sample. One such technique is temperature rising elution fractionation (TREF), as described by Wild et al., J. Poly. Sci., Poly. Phys. Ed., Vol. 20, pp. 441 - 455 (1982), which is hereby incorporated by reference. Generally, a high CDBI indicates that most of the components are eluted in a shorter time period (a smaller temperature range), indicating a narrow comonomer distribution; a low CDBI indicates that most of the components are eluted in a longer time period (a larger temperature range), indicating a broad comonomer distribution.

[0065] Details regarding the determination of the CDBI of a copolymer are known to those skilled in the art. See, for example, PCT Patent Application WO 1993 / 003093 published on February 18, 1993 (which is hereby incorporated by reference), the content regarding CDBI in the specification, such as paragraph 4 on page 13, the transitional paragraphs on pages 14 - 15, the transitional paragraphs on pages 18 - 19, etc. of the specification.

[0066] According to an embodiment of the present invention, the BOCD polyethylene is characterized by having a composition distribution breadth index (CDBI) from about 20 wt% to about 55 wt%. For example, the composition distribution breadth index (CDBI) of the BOCD polyethylene can be ≥ about 20 wt%, such as ≥ about 25 wt%, such as ≥ about 30 wt%, such as ≥ about 40 wt%, such as ≥ about 43 wt%, such as ≥ about 45 wt%, such as ≥ about 50 wt%, such as ≥ about 52 wt%.

[0067] Alternatively or optionally, the compositional distribution breadth index (CDBI) of the BOCD polyethylene can be ≤ about 55 wt%, such as ≤ about 53 wt%, such as ≤ about 50 wt%, such as ≤ about 45 wt%, such as ≤ about 40 wt%, such as ≤ about 35 wt%, such as ≤ about 30 wt%, such as ≤ about 25 wt%. The expressly disclosed ranges include, but are not limited to, ranges formed from any combination of the values listed above, such as from about 20 wt% to about 55 wt%, such as from about 30 wt% to about 50 wt%, such as from about 35 wt% to about 50 wt%, etc.

[0068] Materials and methods for making BOCD polyethylene have been described in the following documents, such as U.S. Patent No. 6,956,088, particularly Example 1; U.S. Patent Application Publication No. 2009 / 0297810, particularly Example 1; U.S. Patent Application Publication No. 2015 / 0291748, particularly PE1 - PE5 in the Examples; and WO 2014 / 099356, particularly PE3 mentioned on page 12 and in the Examples, including the use of, for example, the silica-supported hafnium metallocene / methylaluminoxane catalyst system described in U.S. Patent Nos. 6,242,545 and 6,248,845 (particularly Example 1).

[0069] Many BOCD polyethylenes are commercially available. One or more BOCD polyethylenes are commercially available from: ExxonMobil Chemical Company, Houston, TX, and are sold as Exceed TM XP metallocene polyethylene (mPE). Exceed TM XP mPE provides favorable properties in, for example, dart impact strength, flex crack resistance, and longitudinal (MD) tear, as well as in maintaining stiffness at lower densities. Exceed TM XP mPE also provides a good balance of melt strength, toughness, stiffness, and sealing ability, which makes such polymers very suitable for, for example, blown films.

[0070] In the examples of the present invention, the following BOCD polyethylene is used as the first metallocene polyethylene:

[0071] Exceed TM XP 8784 is a polyethylene purchased from ExxonMobil Chemical Company, Houston, TX, which is a copolymer of ethylene and 1-hexene and has a density of 0.914 g / cm measured according to ASTM D792 3a density and a melt index of 0.80 g / 10 min measured according to ASTM D1238 (190 °C / 2.16 kg), and having a composition distribution breadth index (CDBI) of about 43 wt%.

[0072] A second metallocene polyethylene

[0073] According to an embodiment of the present invention, the non-sticky film for cotton bale wrapping film comprises a first metallocene polyethylene and a second metallocene polyethylene, wherein the second metallocene polyethylene is not a broad orthogonal composition distribution (BOCD) polyethylene.

[0074] According to an embodiment of the present invention, a metallocene polyethylene with a CDBI > 70 wt% is defined as not being a broad orthogonal composition distribution (BOCD) polyethylene.

[0075] According to an embodiment of the present invention, the second metallocene polyethylene has a composition distribution breadth index (CDBI) > 70 wt%. The second metallocene polyethylene of the present invention comprises from about 70 mol% to about 99 mol% of units derived from ethylene, based on the total number of moles of polymer units of the second metallocene polyethylene. Based on the total number of moles of polymer units of the second metallocene polyethylene, the lower limit of the content range of units derived from ethylene can be 70 mol%, 75 mol%, 80 mol%, 85 mol%, 90 mol%, 92 mol%, 94 mol%, 95 mol%, 96 mol%, 97 mol%, 98 mol% or 99 mol%. Based on the total number of moles of polymer units of the second metallocene polyethylene, the upper limit of the content range of units derived from ethylene can be 80 mol%, 85 mol%, 90 mol%, 92 mol%, 94 mol%, 95 mol%, 96 mol%, 97 mol%, 98 mol%, or 99 mol%. Any one of the above upper limit contents can be combined with any one of the above upper limit contents; any one of the above upper limit contents can be combined with any one of the above lower limit contents; and any one of the above upper limit contents can be combined with any one of the above lower limit contents.

[0076] The second metallocene polyethylene of the present invention may have polymer units derived from C3-C20 olefins, such as C3-C20 α-olefins, such as hexene or octene, equal to or less than 30 mol%. Based on the total mole number of the polymer units of the second metallocene polyethylene, the upper limit of the content range of the polymer units derived from C3-C20 olefins may be 30 mol%, 25 mol%, 20 mol%, 15 mol%, 10 mol%, 8 mol%, 6 mol%, 5 mol%, 4 mol%, 3 mol%, 2 mol%, 1 mol% or 0.5 mol%. Based on the total mole number of the polymer units of the second metallocene polyethylene, the lower limit of the content range of the polymer units derived from C3-C20 olefins may be 0 mol%, 1 mol%, 2 mol%, 3 mol%, 4 mol%, 5 mol%, 6 mol%, 8 mol%, 10 mol%, 15 mol%, 20 mol% or 25 mol%. Any of the above upper limit contents may be combined with any of the above upper limit contents; any of the above upper limit contents may be combined with any of the above lower limit contents; and any of the above upper limit contents may be combined with any of the above lower limit contents.

[0077] According to an embodiment of the present invention, the density of the second metallocene polyethylene measured according to ASTM D-792 or ASTM D-1505 may be ≥ about 0.910 g / cm 3 , such as ≥ about 0.911 g / cm 3 , such as ≥ about 0.912 g / cm 3 , such as ≥ about 0.913 g / cm 3 , such as ≥ about 0.914 g / cm 3 , such as ≥ about 0.915 g / cm 3 , such as ≥ about 0.916 g / cm 3 , such as ≥ about 0.917 g / cm 3 , such as ≥ about 0.918 g / cm 3 , such as ≥ about 0.919 g / cm 3 .

[0078] Additionally or alternatively, the density of the second metallocene polyethylene measured according to ASTM D-792 or ASTM D-1505 may be ≤ about 0.920 g / cm 3 , such as ≤ about 0.919 g / cm 3 , such as ≤ about 0.918 g / cm 3 , such as ≤ about 0.917 g / cm 3 , such as ≤ about 0.916 g / cm 3 , such as ≤ about 0.915 g / cm 3, such as ≤ about 0.914 g / cm 3 , such as ≤ about 0.913 g / cm 3 . The explicitly disclosed ranges include, but are not limited to, ranges formed by any combination of the values listed above, such as about 0.910 g / cm 3 - about 0.920 g / cm 3 , about 0.913 g / cm 3 - about 0.920 g / cm 3 , about 0.914 g / cm 3 - about 0.918 g / cm 3 , about 0.915 g / cm 3 - about 0.917 g / cm 3 etc.

[0079] According to an embodiment of the present invention, the melt index (MI, or I 2.16 ) of the second metallocene polyethylene measured according to ASTM D - 1238 (190 °C / 2.16 kg) can be ≥ about 0.1 g / 10 min, such as ≥ about 0.2 g / 10 min, such as ≥ about 0.3 g / 10 min, such as ≥ about 0.4 g / 10 min, such as ≥ about 0.5 g / 10 min, such as ≥ about 0.6 g / 10 min, such as ≥ about 0.7 g / 10 min, such as ≥ about 0.8 g / 10 min, such as ≥ about 0.9 g / 10 min.

[0080] Additionally or alternatively, the melt index (MI, or I 2.16 ) of the second metallocene polyethylene measured according to ASTM D - 1238 (190 °C / 2.16 kg) can be ≤ about 1.0 g / 10 min, such as ≤ about 0.9 g / 10 min, such as ≤ about 0.8 g / 10 min, such as ≤ about 0.7 g / 10 min, such as ≤ about 0.6 g / 10 min, such as ≤ about 0.5 g / 10 min, such as ≤ about 0.4 g / 10 min, such as ≤ about 0.3 g / 10 min. The explicitly disclosed ranges include, but are not limited to, ranges formed by any combination of the values listed above, such as about 0.1 g / 10 min - about 1.0 g / 10 min, such as about 0.2 g / 10 min - about 0.9 g / 10 min.

[0081] The second metallocene polyethylene is commercially available from: ExxonMobil Chemical Company, Houston, TX, and is sold as Exceed TM XP metallocene polyethylene (mPE). Exceed TMXP mPE provides favorable properties in, for example, dart impact strength, flex crack resistance, and machine direction (MD) tear, as well as in maintaining stiffness at lower densities. Exceed TM XP mPE also provides a good balance of melt strength, toughness, stiffness, and sealing ability, making such polymers well-suited for, for example, blown films.

[0082] In embodiments of the present invention, the following metallocene polyethylene is used:

[0083] Exceed TM XP 6026 is a polyethylene purchased from ExxonMobil Chemical Company, Houston, TX, which is a copolymer of ethylene and 1-hexene and has a density of 0.916 g / cm 3 measured according to ASTM D792 and a melt index of 0.20 g / 10 min measured according to ASTM D1238 (190 °C / 2.16 kg). Exceed TM XP 6026 has a compositional distribution breadth index (CDBI) of approximately 80 wt%.

[0084] Low density polyethylene (LDPE)

[0085] According to an embodiment of the present invention, in addition to the first metallocene polyethylene and the second metallocene polyethylene, the non-sticky film for cotton baling film further comprises low density polyethylene (LDPE).

[0086] As is well known in the art, low density polyethylene (LDPE) generally has a branching index (g') < 1.

[0087] According to an embodiment of the present invention, polyethylene having a density of about 0.910 g / cm 3 to about 0.925 g / cm 3 is referred to as low density polyethylene (LDPE), measured according to ASTM D-792 or ASTM D-1505.

[0088] According to an embodiment of the present invention, the lower density limit of low density polyethylene (LDPE) can be about 0.910 g / cm 3 , such as about 0.912 g / cm 3 , such as about 0.914 g / cm 3 , such as about 0.916 g / cm 3 , such as about 0.918 g / cm 3 , such as about 0.920 g / cm 3 , such as about 0.922 g / cm 3 , such as about 0.923 g / cm 3, such as about 0.924 g / cm 3 etc., measured according to ASTM D - 792 or ASTM D - 1505.

[0089] According to an embodiment of the present invention, the upper density limit of low - density polyethylene (LDPE) can be about 0.925 g / cm 3 , such as about 0.924 g / cm 3 , such as about 0.923 g / cm 3 , such as about 0.922 g / cm 3 , such as about 0.920 g / cm 3 , such as about 0.918 g / cm 3 , such as about 0.916 g / cm 3 , such as about 0.914 g / cm 3 , such as about 0.912 g / cm 3 etc., measured according to ASTM D - 792 or ASTM D - 1505. The explicitly disclosed ranges include, but are not limited to, ranges formed by any combination of the values listed above.

[0090] According to an embodiment of the present invention, low - density polyethylene (LDPE) has a melt index ranging from greater than about 0.5 g / 10 min to less than about 2.0 g / 10 min, measured according to ASTM D - 1238 - E (190 °C / 2.16 kg), such as about 0.6 g / 10 min, such as about 0.7 g / 10 min, such as about 0.8 g / 10 min, such as about 0.9 g / 10 min, such as about 1.0 g / 10 min, such as about 1.2 g / 10 min, such as about 1.5 g / 10 min, such as about 1.7 g / 10 min, etc. The explicitly disclosed ranges include, but are not limited to, ranges formed by any combination of the values listed above.

[0091] The low - density polyethylene (LDPE) that can be used in the present invention can be obtained from various sources, for example, the LD series of low - density polyethylene from ExxonMobil Chemical Company, Houston, TX.

[0092] ExxonMobil TM LDPE LD150 is used as the low - density polyethylene in the examples of the present invention, and it is purchased from ExxonMobil Chemical Company, Houston, TX.

[0093] ExxonMobil TM LDPE LD150 has the following performance parameters:

[0094] Density: 0.923 g / cm 3 , measured according to ASTM D-1505;

[0095] Melt Index: 0.75 g / 10 min, measured according to ASTM D-1238-E (190 °C / 2.16 kg).

[0096] Linear Low-Density Polyethylene (LLDPE)

[0097] According to an embodiment of the present invention, in addition to the first metallocene polyethylene and the second metallocene polyethylene, the non-sticky film for cotton bale wrapping further comprises linear low-density polyethylene (LLDPE).

[0098] According to an embodiment of the present invention, linear polyethylene having a density of about 0.910 g / cm 3 to about 0.925 g / cm 3 is referred to as linear low-density polyethylene (LLDPE), where the density is measured according to ASTM D-792 or ASTM D-1505, and where "linear" means that the polyethylene does not have long-chain branches or has only a small number of long-chain branches. It is well known in the art that linear low-density polyethylene (LLDPE) typically has a branching index (g') of approximately 1.

[0099] According to an embodiment of the present invention, the lower density limit of linear low-density polyethylene (LLDPE) can be about 0.910 g / cm 3 , such as about 0.912 g / cm 3 , such as about 0.914 g / cm 3 , such as about 0.916 g / cm 3 , such as about 0.918 g / cm 3 , such as about 0.920 g / cm 3 , such as about 0.922 g / cm 3 , such as about 0.923 g / cm 3 , such as about 0.924 g / cm 3 etc., measured according to ASTM D-792 or ASTM D-1505.

[0100] According to an embodiment of the present invention, the upper density limit of linear low-density polyethylene (LLDPE) can be about 0.925 g / cm 3 , such as about 0.924 g / cm 3 , such as about 0.923 g / cm 3 , such as about 0.922 g / cm 3 , such as about 0.920 g / cm 3 , such as about 0.918 g / cm 3, such as approximately 0.916 g / cm 3 , such as approximately 0.914 g / cm 3 , such as approximately 0.912 g / cm 3 and so on, measured according to ASTM D-792 or ASTM D-1505. The explicitly disclosed ranges include, but are not limited to, ranges formed by any combination of the values listed above.

[0101] According to an embodiment of the present invention, linear low density polyethylene (LLDPE) has a melt index ranging from greater than approximately 0.5 g / 10 min to less than approximately 2.0 g / 10 min, measured according to ASTM D-1238-E (190 °C / 2.16 kg), such as approximately 0.6 g / 10 min, such as approximately 0.7 g / 10 min, such as approximately 0.8 g / 10 min, such as approximately 0.9 g / 10 min, such as approximately 1.0 g / 10 min, such as approximately 1.2 g / 10 min, such as approximately 1.5 g / 10 min, such as approximately 1.7 g / 10 min, and so on. The explicitly disclosed ranges include, but are not limited to, ranges formed by any combination of the values listed above.

[0102] The linear low density polyethylene (LLDPE) that can be used in the present invention can be obtained from various sources, for example, the LL series linear low density polyethylene from ExxonMobil Chemical Company, Houston, TX.

[0103] ExxonMobil is used in the examples of the present invention TM LLDPE LL 1001AV as the linear low density polyethylene, which is purchased from ExxonMobil Chemical Company, Houston, TX.

[0104] ExxonMobil TM LLDPE LL 1001AV has the following performance parameters:

[0105] Density: 0.918 g / cm 3 , which is measured according to ASTM D792;

[0106] Melt index: 1.0 g / 10 min, which is measured according to ASTM D-1238-E (190 °C / 2.16 kg).

[0107] High density polyethylene (HDPE)

[0108] According to an embodiment of the present invention, in addition to the first metallocene polyethylene and the second metallocene polyethylene, the non-sticky film for cotton bale wrapping further comprises high density polyethylene (HDPE).

[0109] According to the general definition in the art, an ethylene polymer with a density greater than about 0.950 g / cm 3 is referred to as "high-density polyethylene (HDPE)", where the density is measured according to ASTM D-792 or ASTM D-1505.

[0110] According to an embodiment of the present invention, the density of high-density polyethylene (HDPE) can be greater than 0.950 g / cm 3 , for example, ≥ about 0.960 g / cm 3 and so on.

[0111] According to an embodiment of the present invention, high-density polyethylene (HDPE) has a melt index ranging from greater than about 0.5 g / 10 min to less than about 2.0 g / 10 min, measured according to ASTM D-1238-E (190 °C / 2.16 kg), for example, about 0.6 g / 10 min, for example, about 0.7 g / 10 min, for example, about 0.8 g / 10 min, for example, about 0.9 g / 10 min, for example, about 1.0 g / 10 min, for example, about 1.2 g / 10 min, for example, about 1.5 g / 10 min, for example, about 1.7 g / 10 min and so on. The explicitly disclosed ranges include, but are not limited to, the ranges formed by any combination of the above-listed values.

[0112] The high-density polyethylene (HDPE) that can be used in the present invention can be obtained from various sources. For example, the HTA series of high-density polyethylene from ExxonMobil Chemical Company, Houston, TX.

[0113] ExxonMobil TM HDPE HTA 108 is used as the high-density polyethylene in the examples of the present invention, and it is purchased from ExxonMobil Chemical Company, Houston, TX.

[0114] ExxonMobil TM HDPE HTA 108 has the following performance parameters:

[0115] Density: 0.961 g / cm 3 , measured according to ASTM D-1505;

[0116] Melt index: 0.70 g / 10 min, measured according to ASTM D-1238-E (190 °C / 2.16 kg).

[0117] Method for producing the film

[0118] The non - sticky film for cotton packing film of the present invention is produced by the blown film process known in the art.

[0119] The composition is extruded through an annular die in a molten state and then expanded to form a uniaxially or biaxially oriented melt. Then it is cooled to form a tubular blown film. Then it can be axially cut and unrolled to form a flat film. The film can subsequently be unoriented, uniaxially oriented, or biaxially oriented to the same or different degrees.

[0120] According to an embodiment of the present invention, the non - sticky film is first produced by a blown film production line, and then the sticky film is produced by the blown film production line. After that, the non - sticky film and the sticky film are combined together. Description of the Drawings

[0121] Figure 1 Illustrate the structure of the cotton packing film, which includes a non - sticky film and a sticky film.

[0122] Figure 2 Show the comparison of various properties of the non - sticky film produced in the examples of the present invention and the non - sticky film of the comparative example, where the solid line represents the non - sticky film produced in the examples of the present invention, and the dashed line represents the non - sticky film of the comparative example. Detailed Description of the Invention

[0123] To better understand the technical solution of the present invention, the applicant provides the following examples for illustration. The examples are only for the purpose of illustration and do not impose any limitation on the protection scope of the present invention.

[0124] Measurement Method

[0125] The present invention uses the following measurement methods.

[0126] Table 1

[0127] Measurement method TD Elmendorf Tear (g / μm) ASTM D1922-09 MD Elmendorf Tear (g / μm) ASTM D1922-09 MD 1% Secant Modulus (MPa) ASTM D-882 MD Tensile Strength at Break (N) ASTM D-882 MD Elongation at Break (%) ASTM D-882

[0128] Examples

[0129] According to the composition shown in Table 2, a non - sticky film for cotton packing film with an A / B / C / D / E configuration is produced on a blown film production line, where the total thickness of the 5 - layer non - sticky film is about 75.0 μm, and the thickness ratio of each layer A:B:C:D:E is 1:2:3:3:1.

[0130] The examples of the present invention use the following raw materials:

[0131] First metallocene polyethylene: Exceed TM XP 8784, denoted as "8784" in Table 2;

[0132] Second metallocene polyethylene: Exceed TMXP 6026, denoted as "6026" in Table 2;

[0133] Low-density polyethylene: ExxonMobil TM LDPE LD150, denoted as "LDPE" in Table 2;

[0134] Linear low-density polyethylene: ExxonMobil TM LLDPE LL 1001AV, denoted as "LLDPE" in Table 2;

[0135] High-density polyethylene: ExxonMobil TM HDPE HTA 108, denoted as "HDPE" in Table 2.

[0136] In Table 2, the content in each of the A / B / C / D / E layers (expressed in weight %) is based on the total weight of the respective layer, for example, based on the weight of layer A, B, C, D, or E respectively.

[0137] In Table 2, "dosage" represents the content (expressed in weight %) of 6026, 8784, LDPE, LLDPE, and HDPE respectively based on the total weight of the 5-layer non-adhesive film.

[0138] Table 2

[0139] Layer A B C D E Dose 6026 70 wt% 30 wt% 70 wt% 70 wt% 51 wt% LDPE 60 wt% 10 wt% 20 wt% 10 wt% 17 wt% HDPE 40 wt% 12 wt% LLDPE 40 wt% 10 wt% 7 wt% 8784 20 wt% 20 wt% 30 wt% 13 wt%

[0140] The properties of the non-adhesive films produced in the examples of the present invention and the non-adhesive films of the comparative examples are shown in Table 3, where the non-adhesive films of the comparative examples are commercially obtained, and the manufacturer is Changzhou Kaide New Material Technology Co., Ltd. The non-adhesive films of the comparative examples also have a thickness of about 75.0 μm, which is based on Exceed TM non-adhesive film of XP 6026. The non-adhesive films of the comparative examples do not contain Exceed TM XP 8784 used in the present invention.

[0141] In the comparative examples, the content of metallocene polyethylene ranges from about 61 wt% to about 65 wt%, based on the total weight of the non-adhesive film.

[0142] The content of metallocene polyethylene in the examples of the present invention is about 64 wt%, that is, the content of Exceed TM XP 6026 + the content of Exceed TM XP 8784 (51 wt% + 13 wt%).

[0143] Table 3

[0144] Non-sticky film of the embodiment of the present invention Non-sticky film of the comparative example TD Elmendorf Tear (g / μm) 20.5 19.1 MD Elmendorf Tear (g / μm) 6.1 5.1 MD 1% Secant Modulus (MPa) 340 367 MD Tensile Strength at Break (N) 39.9 37.5 MD Elongation at Break (%) 627 624

[0145] As can be seen from Table 3, the non-sticky film of the present invention has an MD Elmendorf tear of up to 6.1 g / μm, indicating that the non-sticky film of the present invention has excellent MD tear resistance. Compared with the non-sticky film of the comparative example, the non-sticky film of the present invention has an MD Elmendorf tear increased by 19.6%.

[0146] Moreover, the non-sticky film of the present invention has a TD Elmendorf tear of 20.5 g / μm, indicating that the non-sticky film of the present invention has excellent TD tear resistance. Compared with the non-sticky film of the comparative example, the non-sticky film of the present invention has a TD Elmendorf tear increased by 7.3%.

[0147] In addition, from the Figure 2 it can be seen that compared with the non-sticky film of the comparative example, the non-sticky film of the present invention performs better in the following five aspects: TD Elmendorf tear, MD Elmendorf tear, MD 1% secant modulus, MD breaking tensile strength, MD elongation at break.

[0148] In particular, compared with the non-sticky film of the comparative example, the non-sticky film of the present invention has a significantly increased MD Elmendorf tear, indicating that the non-sticky film of the present invention has excellent MD tear resistance.

[0149] All documents described herein, including any priority documents and / or test procedures, are incorporated by reference in all jurisdictions not inconsistent with the present invention. From the above summary and specific embodiments, it is apparent that while the form of the present disclosure has been illustrated and described, various modifications can be made without departing from the spirit and scope of the present disclosure. Therefore, the present disclosure is not intended to be limited thereby. Similarly, the term "comprising" is considered synonymous with the term "including". Also, whenever a composition, element, or group of elements is preceded by the transitional term "comprising", it should be understood that the same composition or group of elements with the transitional terms "consisting essentially of...", "consisting of...", "selected from", or "is" preceding the recited composition, element, or each element is also contemplated, and vice versa.

[0150] For the sake of simplicity, only certain numerical ranges are explicitly disclosed herein. However, a given lower limit can be combined with any other upper limit to define a range not explicitly recited, similarly, a given lower limit can be combined with any other lower limit to define a range not explicitly recited, and likewise, a given upper limit can be combined with any upper limit to define a range not explicitly recited. Additionally, even if not explicitly recited, each point or individual value between the endpoints is included within the range. Thus, each point or individual value itself can be used as a lower or upper limit in combination with other points or individual values or other lower or upper limits to define a range not explicitly recited.

Claims

1. Non - sticky film for cotton bale wrapping film, wherein the cotton bale wrapping film comprises a sticky film and a non - sticky film, and the non - sticky film has a configuration of A / B / C / D / E, layer A is in contact with the sticky film and layer E is in contact with the cotton, wherein each of layers A, B, C, D and E comprises a first metallocene polyethylene, a second metallocene polyethylene, low - density polyethylene, high - density polyethylene and / or linear low - density polyethylene, and the first metallocene polyethylene is BOCD polyethylene and the second metallocene polyethylene is not BOCD polyethylene; The first metallocene polyethylene and the second metallocene polyethylene are not present in layer A, the second metallocene polyethylene is present in each of layers B, D, E at a content of at least 60% by weight, based on the weight of each of layers B, D, E, and the second metallocene polyethylene is present in layer C at a content of at least 20% by weight, based on the weight of layer C, Based on the total weight of layers A, B, C, D, and E of the non-adhesive film, the content of the first metallocene polyethylene is 10 wt% - 25 wt%, where the first metallocene polyethylene contains 70 mol% to 99 mol% of polymer units derived from ethylene, based on the total molar number of the polymer units of the first metallocene polyethylene, and has a density of 0.910 g / cm 3 to 0.920 g / cm 3 , which is measured according to ASTM D-792 or ASTM D-1505, and a melt index I 2.16 of 0.1 g / 10 min to 1.0 g / 10 min, which is measured according to ASTM D-1238-E (190 °C / 2.16 kg), and the first metallocene polyethylene has a composition distribution breadth index (CDBI) of from 20 wt% to 55 wt%, Based on the total weight of layers A, B, C, D, and E of the non-sticky film, the content of the second metallocene polyethylene is 40 wt% - 65 wt%, where the second metallocene polyethylene contains 70 mol% to 99 mol% of polymer units derived from ethylene, based on the total molar number of the polymer units of the second metallocene polyethylene, and a density of 0.910 g / cm 3 to 0.920 g / cm 3 , which is measured according to ASTM D-792 or ASTM D-1505, and a melt index I 2.16 of 0.1 g / 10 min to 1.0 g / 10 min, which is measured according to ASTM D-1238-E (190 °C / 2.16 kg), and the second metallocene polyethylene has a composition distribution breadth index (CDBI) of >70 wt%, Based on the total weight of layers A, B, C, D, E of the non - sticky film, the content of low - density polyethylene is 10% - 20% by weight, Based on the total weight of layers A, B, C, D, E of the non - sticky film, the content of high - density polyethylene is 10% - 15% by weight, and Based on the total weight of layers A, B, C, D, E of the non - sticky film, the content of linear low - density polyethylene is 2% - 10% by weight.

2. The non-stick film according to claim 1, wherein the low density polyethylene (LDPE) has a density of 0.910 g / cm 3 to 0.925 g / cm 3 and has a melt index of greater than 0.5 g / 10 min to less than 2.0 g / 10 min, measured according to ASTM D-1238-E (190 °C / 2.16 kg).

3. The non-sticky film according to any one of claims 1-2, wherein the linear low density polyethylene (LLDPE) has a density of 0.910 g / cm 3 to 0.925 g / cm 3 and has a melt index of greater than 0.5 g / 10 min to less than 2.0 g / 10 min, measured according to ASTM D-1238-E (190 °C / 2.16 kg).

4. Non-stick film according to any one of claims 1 - 3, wherein the high-density polyethylene (HDPE) has a density greater than 0.950 g / cm 3 measured according to ASTM D-792 or ASTM D-1505, and has a melt index ranging from greater than 0.5 g / 10 min to less than 2.0 g / 10 min, measured according to ASTM D-1238-E (190 °C / 2.16 kg).

5. The non - sticky film according to any one of claims 1 - 4, wherein the non - sticky film has a TD Elmendorf tear greater than 19.0 g / μm to 25.0 g / μm, and the TD Elmendorf tear is determined according to the ASTM D1922 - 09 test method.

6. The non - sticky film according to any one of claims 1 - 5, wherein the non - sticky film has an MD Elmendorf tear greater than 5.0 g / μm to 10.0 g / μm, and the MD Elmendorf tear is determined according to the ASTM D1922 - 09 test method.

7. Non - sticky film for cotton bale wrapping film, wherein the cotton bale wrapping film comprises a sticky film and a non - sticky film, and the non - sticky film has a configuration of A / B / C / D / E, layer A is in contact with the sticky film and layer E is in contact with the cotton, wherein each of layers A, B, C, D and E comprises a first metallocene polyethylene, a second metallocene polyethylene, low - density polyethylene, high - density polyethylene and / or linear low - density polyethylene, and the first metallocene polyethylene is BOCD polyethylene and the second metallocene polyethylene is not BOCD polyethylene; The first metallocene polyethylene and the second metallocene polyethylene are not present in layer A, the second metallocene polyethylene is present in each of layers B, D, E at a content of at least 60% by weight, based on the weight of each of layers B, D, E, and the second metallocene polyethylene is present in layer C at a content of at least 20% by weight, based on the weight of layer C, Based on the total weight of layers A, B, C, D, and E of the non-sticky film, the content of the first metallocene polyethylene is 10 wt% - 25 wt%, where the first metallocene polyethylene contains 70 mol% to 99 mol% of polymer units derived from ethylene, based on the total mole number of the polymer units of the first metallocene polyethylene, and a density of 0.914 g / cm 3 , which is measured according to ASTM D-792, and a melt index I 2.16 of 0.80 g / 10 min, which is measured according to ASTM D-1238-E (190 °C / 2.16 kg), and the first metallocene polyethylene has a compositional distribution breadth index (CDBI) of 43 wt%, Based on the total weight of layers A, B, C, D, and E of the non-tacky film, the content of the second metallocene polyethylene is 40 wt% - 65 wt%, wherein the second metallocene polyethylene contains 70 mol% to 99 mol% of polymer units derived from ethylene, based on the total molar number of the polymer units of the second metallocene polyethylene, and a density of 0.916 g / cm 3 , which is measured according to ASTM D-792, and a melt index I 2.16 of 0.20 g / 10 min, which is measured according to ASTM D-1238-E (190 °C / 2.16 kg), and the second metallocene polyethylene has a compositional distribution breadth index (CDBI) of 80 wt%, Based on the total weight of layers A, B, C, D, and E of the non-adhesive film, the content of low-density polyethylene is 10 wt% - 20 wt%, where the low-density polyethylene (LDPE) has a density of 0.923 g / cm 3 , which is measured according to ASTM D-1505, and has a melt index of 0.75 g / 10 min, measured according to ASTM D-1238-E (190 °C / 2.16 kg). Based on the total weight of layers A, B, C, D, and E of the non-stick film, the content of high-density polyethylene is 10% to 15% by weight, where the high-density polyethylene (HDPE) has a density of 0.961 g / cm 3 measured according to ASTM D-1505, and a melt index of 0.70 g / 10 min, measured according to ASTM D-1238-E (190 °C / 2.16 kg), and Based on the total weight of layers A, B, C, D, and E of the non-adhesive film, the content of linear low density polyethylene is 2 wt% - 10 wt%, where the linear low density polyethylene (LLDPE) has a density of 0.918 g / cm 3 , which is measured according to ASTM D-792, and a melt index of 1.0 g / 10min, which is measured according to ASTM D-1238-E (190 °C / 2.16 kg).

8. The non - sticky film according to claim 7, wherein the non - sticky film has a TD Elmendorf tear greater than 19.0 g / μm to 25.0 g / μm, and the TD Elmendorf tear is determined according to the ASTM D1922 - 09 test method.

9. The non-sticky film according to any one of claims 7-8, wherein the non-sticky film has an MD Elmendorf tear of greater than 5.0 g / μm to 10.0 g / μm, and the MD Elmendorf tear is determined according to the ASTM D1922-09 test method.

10. A cotton baling film, which comprises the non-sticky film according to any one of claims 1-9.

11. A method for producing the non-sticky film according to any one of claims 1-9, which is produced by a blown film process.

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