Low-density polyethylene having biaxial stretching property and method for producing same

Abstract

The present invention relates to low-density polyethylene having biaxial stretching property and a method for producing same. Specifically, the method for producing low-density polyethylene comprises polymerizing ethylene and α-olefin at a specific concentration ratio under a hybrid metallocene catalyst while controlling the crystallinity within a specific range. The resulting low-density polyethylene exhibits high processability suitable for biaxial stretching processing and may have excellent optical properties. In addition, the low-density polyethylene may replace the base layer of existing packaging materials, thereby enabling the production of single-material packaging materials and thus providing an environmentally friendly packaging material with an improved recyclability.

Description

Low-density polyethylene having biaxial stretching properties and method for producing the same

[0001] The present invention relates to low-density polyethylene having biaxial stretching properties and a method for producing the same.

[0002] Conventional packaging materials often incorporate a mixture of materials, such as polyethylene terephthalate (PET), nylon, or polyamide (PA) layers within a polyethylene inner layer. These composite packaging materials present challenges in the recycling process, requiring the separation of individual materials. This complicates the recycling process, increasing processing costs and reducing recycling rates. To address these environmental concerns, attempts have been made to utilize a single-material packaging material using biaxially oriented polyethylene (BOPE) as the substrate. However, conventional polyethylene faces limitations, such as the difficulty of biaxially oriented processing and the uneven film formation, hindering its application to products.

[0003] To overcome these limitations, the inventors of the present invention have produced low-density polyethylene that is capable of biaxial stretching and has excellent optical properties by polymerizing an appropriate ratio of ethylene and α-olefin under a hybrid metallocene catalyst of a specific composition.

[0004] The purpose of the present invention is to provide a low-density polyethylene having high processability that allows biaxial stretching and excellent optical properties, and a method for producing the same, using a hybrid metallocene catalyst.

[0005] Another object of the present invention is to provide a single-material packaging material by using the low-density polyethylene to replace existing materials such as polyethylene terephthalate (PET), nylon, and polyamide (PA) used as a base layer of packaging materials.

[0006] The present invention relates to a method for producing low-density polyethylene by polymerizing ethylene and α-olefin (alpha-olefin) under a hybrid metallocene catalyst including a transition metal compound represented by the following chemical formulas 1 and 2, wherein the concentration ratio (R) of α-olefin to ethylene is H ) is polymerized to 0.65 to 0.85.

[0007] [Chemical Formula 1]

[0008]

[0009] [Chemical Formula 2]

[0010]

[0011] In the above chemical formulas 1 and 2, M 1 and M 2 are each independently titanium (Ti), zirconium (Zr) or hafnium (Hf), and X and Y are each independently halogen, C 1-20 Alkyl, C 2-20 Alkenyl, C 2-20 alkynyl, C 6-20 Aryl, C 1-20 Alkyl C 6-20 Aryl, C 6-20 Aryl C 1-20 Alkyl, C 1-20 Alkylamido, C 6-20 Arylamido or C 1-20 It is alkylidene,

[0012] R1 to R 10 are each independently hydrogen, substituted or unsubstituted C 1-20 Alkyl, substituted or unsubstituted C 2-20 Alkenyl, substituted or unsubstituted C 6-20 Aryl, substituted or unsubstituted C 1-20 Alkyl C 6-20 Aryl, substituted or unsubstituted C 6-20 Aryl C 1-20 Alkyl, substituted or unsubstituted C 1-20 Heteroalkyl, substituted or unsubstituted C 3-20 Heteroaryl, substituted or unsubstituted C1-20 Alkylamido, substituted or unsubstituted C 6-20 Arylamido, substituted or unsubstituted C 1-20 Alkylidene, or substituted or unsubstituted C 1-20 It is a cylinder, R1 to R 10 Each independently adjacent group is connected to form a substituted or unsubstituted saturated or unsaturated C 4-20 It can form a ring.

[0013] In one embodiment, the α-olefin is C 4-20 It may be an α-olefin.

[0014] In one aspect, the hybrid metallocene catalyst may be a supported catalyst in which a transition metal compound and a cocatalyst are supported on a support.

[0015] In one embodiment, the cocatalyst may be one or more selected from the group consisting of compounds represented by the following chemical formulas 3 to 5.

[0016] [Chemical Formula 3]

[0017]

[0018] [Chemical Formula 4]

[0019]

[0020] [Chemical Formula 5]

[0021] [LH] + [Z(A)4] - or [L] + [Z(A)4] -

[0022] In the above chemical formulas 3 to 5,

[0023] n is an integer greater than or equal to 2, and R 11 Silver halogen, C 1-20 C substituted with an alkyl group or halogen 1-20 is an alkyl group,

[0024] D is aluminum (Al) or boron (B), and R 12 , R 13 and R14 are each independently halogen, C 1-20 C, a straight or branched chain alkyl group, substituted with halogen 1-20 alkyl group or C 1-20 is an alkoxy group,

[0025] L is a neutral or cationic Lewis base, [LH] + and [L] + is a Bronsted acid, Z is a group 13 element, and A is C 6-20 Aryl group of or C 1-20 is an alkyl group.

[0026] In one embodiment, the carrier may be a mixture of one or more selected from the group consisting of silica, aluminum oxide, and magnesium oxide.

[0027] In one embodiment, the method for producing low-density polyethylene may be a method of continuously gas-phase polymerizing ethylene and α-olefin in a fluidized bed reactor.

[0028] In one embodiment, the method for producing low-density polyethylene may be a method for polymerizing ethylene and α-olefin at a temperature of 70 to 90°C.

[0029] In one aspect, the above low-density polyethylene manufacturing method has a crystallinity (X) satisfying the following equation 1 c ) can be adjusted to polymerize.

[0030] [Formula 1]

[0031] -100R H + 116.2 <X c <-100R H +118.2

[0032] In the above equation 1, R H is the concentration ratio of α-olefin to ethylene, and 0.65≤R H ≤0.85.

[0033] Another aspect of the present invention is a low-density polyethylene resin polymerized with ethylene and α-olefin under a hybrid metallocene catalyst comprising a transition metal compound represented by the following chemical formulas 1 and 2, wherein the crystallinity (X) of the low-density polyethylene resin c ) provides a low-density polyethylene resin that satisfies the following equation 1.

[0034] [Formula 1]

[0035] -100R H + 116.2 <X c <-100R H +118.2

[0036] In the above equation 1, R H is the concentration ratio of α-olefin to ethylene, and 0.65≤R H ≤0.85.

[0037] [Chemical Formula 1]

[0038]

[0039] [Chemical Formula 2]

[0040]

[0041] In the above chemical formulas 1 and 2, M 1 and M 2 are each independently titanium (Ti), zirconium (Zr) or hafnium (Hf), and X and Y are each independently halogen, C 1-20 Alkyl, C 2-20 Alkenyl, C 2-20 alkynyl, C 6-20 Aryl, C 1-20 Alkyl C 6-20 Aryl, C 6-20 Aryl C 1-20 Alkyl, C 1-20 Alkylamido, C 6-20 Arylamido or C 1-20 It is alkylidene,

[0042] R1 to R 10 are each independently hydrogen, substituted or unsubstituted C 1-20 Alkyl, substituted or unsubstituted C2-20 Alkenyl, substituted or unsubstituted C 6-20 Aryl, substituted or unsubstituted C 1-20 Alkyl C 6-20 Aryl, substituted or unsubstituted C 6-20 Aryl C 1-20 Alkyl, substituted or unsubstituted C 1-20 Heteroalkyl, substituted or unsubstituted C 3-20 Heteroaryl, substituted or unsubstituted C 1-20 Alkylamido, substituted or unsubstituted C 6-20 Arylamido, substituted or unsubstituted C 1-20 Alkylidene, or substituted or unsubstituted C 1-20 It is a cylinder, R1 to R 10 Each independently adjacent group is connected to form a substituted or unsubstituted saturated or unsaturated C 4-20 It can form a ring.

[0043] In one embodiment, the low-density polyethylene resin can be subjected to biaxial stretching, and can be stretched at least four times in the machine direction (MD) and at least four times in the transverse direction (TD) of a low-density polyethylene having a width of 10 cm, a length of 10 cm, and a thickness of 1 mm at a speed of 3 cm / s.

[0044] In one embodiment, the melt index (MI) of the low-density polyethylene resin measured at 190° C. under a load of 2.16 kg according to ASTM D1238 may be 0.50 to 1.50 g / 10 min.

[0045] In one embodiment, the melt index (MI) of the low-density polyethylene resin, measured at 190° C. under a load of 21.6 kg according to ASTM D1238, may be 10 to 30 g / 10 min.

[0046] In one embodiment, the melt flow rate (MFR) of the low-density polyethylene resin measured at 190°C according to ASTM D1238 may be 15 to 30 g / 10 min.

[0047] In one embodiment, the density of the low-density polyethylene resin is 0.945 g / cm 3 It could be as follows:

[0048] In one embodiment, the number average molecular weight of the low-density polyethylene resin may be 15,000 to 50,000 g / mol.

[0049] In one embodiment, the weight average molecular weight of the low-density polyethylene resin may be 100,000 to 300,000 g / mol.

[0050] In one embodiment, the z-average molecular weight of the low-density polyethylene resin may be 350,000 g / mol or more.

[0051] In one aspect, the melting temperature (T) of the low-density polyethylene resin m ) may be between 120 and 130 ℃.

[0052] Another aspect of the present invention provides a low-density polyethylene film comprising the low-density polyethylene resin.

[0053] In one aspect, the low-density polyethylene film may have a haze of 20% or less according to ASTM D 1003.

[0054] Another aspect of the present invention provides a packaging material made of a low-density polyethylene film including the low-density polyethylene resin.

[0055] Low-density polyethylene according to one aspect of the present invention exhibits high processability that allows biaxial stretching processing by polymerizing ethylene and α-olefin at a specific concentration ratio under a hybrid metallocene catalyst while controlling the crystallinity to a specific range, and can have excellent optical properties.

[0056] Low-density polyethylene according to one aspect of the present invention can replace the base layer of existing packaging materials, enabling the production of single-material packaging materials, thereby providing environmentally friendly packaging materials with improved recyclability.

[0057] The present invention will be described in more detail below. However, the following specific examples or examples are merely references for explaining the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms.

[0058] Additionally, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing specific embodiments only and is not intended to be limiting.

[0059] Additionally, the singular forms used in the specification and the appended claims are intended to include the plural forms as well, unless the context clearly dictates otherwise.

[0060] Additionally, when a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0061] Additionally, unless otherwise specifically defined in the present invention, when a layer or member is said to be located “on” another layer or member, this includes not only cases where a layer or member is in contact with another layer or member, but also cases where another layer or another member exists between the two layers or two members.

[0062] In addition, the terms "about", "substantially", etc. used in this specification are used in a meaning close to or at the numerical value when manufacturing and material tolerances inherent to the meanings mentioned are presented, and are used to prevent unscrupulous infringers from unfairly using the disclosure contents in which exact or absolute values ​​are mentioned to aid understanding of the present invention.

[0063] To address the difficulty of biaxially oriented polyethylene, which has hindered its application as a single packaging material, the present inventors devised a manufacturing method in which an appropriate ratio of ethylene and α-olefin is polymerized in the presence of a hybrid metallocene catalyst of a specific composition. The inventors discovered that this manufacturing method not only enables biaxial oriented processing but also produces low-density polyethylene with excellent haze characteristics, thereby completing the present invention.

[0064] The present invention will be described below.

[0065] The present invention relates to a method for producing low-density polyethylene by polymerizing ethylene and α-olefin (alpha-olefin) under a hybrid metallocene catalyst including a transition metal compound represented by the following chemical formulas 1 and 2, wherein the concentration ratio (R) of α-olefin to ethylene is H ) is polymerized to 0.65 to 0.85.

[0066] [Chemical Formula 1]

[0067]

[0068] [Chemical Formula 2]

[0069]

[0070] In the above chemical formulas 1 and 2, M 1 and M 2 are each independently titanium (Ti), zirconium (Zr) or hafnium (Hf), and X and Y are each independently halogen, C 1-20 Alkyl, C 2-20Alkenyl, C 2-20 alkynyl, C 6-20 Aryl, C 1-20 Alkyl C 6-20 Aryl, C 6-20 Aryl C 1-20 Alkyl, C 1-20 Alkylamido, C 6-20 Arylamido or C 1-20 It is alkylidene,

[0071] R1 to R 10 are each independently hydrogen, substituted or unsubstituted C 1-20 Alkyl, substituted or unsubstituted C 2-20 Alkenyl, substituted or unsubstituted C 6-20 Aryl, substituted or unsubstituted C 1-20 Alkyl C 6-20 Aryl, substituted or unsubstituted C 6-20 Aryl C 1-20 Alkyl, substituted or unsubstituted C 1-20 Heteroalkyl, substituted or unsubstituted C 3-20 Heteroaryl, substituted or unsubstituted C 1-20 Alkylamido, substituted or unsubstituted C 6-20 Arylamido, substituted or unsubstituted C 1-20 Alkylidene, or substituted or unsubstituted C 1-20 It is a cylinder, R1 to R 10 Each independently adjacent group is connected to form a substituted or unsubstituted saturated or unsaturated C 4-20 It can form a ring.

[0072] In one aspect, in the above chemical formulas 1 and 2, a specific example is M 1 and M 2 are different and are each zirconium or hafnium, and X and Y are each halogen or C 1-20 Alkyl, R1 to R 10 Each of these is hydrogen, substituted or unsubstituted C 1-20 Alkyl, substituted or unsubstituted C 1-20 Alkenyl, or substituted or unsubstituted C 6-20It may be aryl, but is not limited thereto. Preferred specific examples of the present invention include M 1 This zirconium (Zr), M 2 It can be that X is hafnium (Hf), X is chlorine (Cl), and Y is methyl (Me).

[0073] C above 1-20 Alkyl may be straight-chain, branched-chain or cyclic alkyl. Specifically, the C 1-20 Alkyl is C 1-20 Straight chain alkyl, C 1-10 Straight chain alkyl, C 1-5 Straight chain alkyl, C 3-20　 Branched or cyclic alkyl, C 3-15 Branched or cyclic alkyl, or C 3-10 It may be a branched or cyclic alkyl. More specifically, it may have carbon number C. 1-20 Alkyl may be, but is not limited to, a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, an n-hexyl group, or a cyclohexyl group.

[0074] C above 2-20 Alkenyl may be straight-chain, branched-chain or cyclic alkenyl. Specifically, the above C 2-20 Alkenyl is C 2-20 Straight-chain alkenyl, C 2-10 Straight-chain alkenyl, C 2-5 Straight-chain alkenyl, C 3-20 Branched-chain alkenyl, C 3-15 Branched-chain alkenyl, C 3-10 Branched-chain alkenyl, C 5-20 Cyclic alkenyl or C 5-10 It may be a cyclic alkenyl. More specifically, C 2-20 Alkenyl may be, but is not limited to, ethenyl, propenyl, butenyl, pentenyl, or cyclohexenyl.

[0075] C above 6-20Aryl can mean a monocyclic, bicyclic, or tricyclic aromatic hydrocarbon. Specifically, C 6-20 Aryl may be, but is not limited to, a phenyl group, a naphthyl group, or anthracenyl group.

[0076] C above 1-20 Alkyl C 6-20 Aryl may mean a substituent in which one or more hydrogens of aryl are replaced by alkyl. Specifically, the C 6-20 Alkylaryl may be, but is not limited to, methylphenyl, ethylphenyl, n-propylphenyl, iso-propylphenyl, n-butylphenyl, iso-butylphenyl, tert-butylphenyl, or cyclohexylphenyl.

[0077] C above 6-20 Aryl C 1-20 Alkyl may mean a substituent in which one or more hydrogens of alkyl are replaced by aryl. Specifically, the above C 6-20 Arylalkyl may be, but is not limited to, benzyl, phenylpropyl, or phenylhexyl.

[0078] C above 1-20 Alkylamido may refer to a substituent in which one or more hydrogens of an amino group (-NH2) are replaced by alkyl. The alkyl is the aforementioned C 1-20 It may be the same as an example of alkyl. Specifically, the above C 1-20 Alkylamido may be, but is not limited to, methylamido, ethylamido, propylamido, butylamido, pentylamido, or hexylamido.

[0079] C above 6-20 Arylamido may refer to a substituent in which one or more hydrogens of an amino group (-NH2) are replaced by aryl. The aryl is the aforementioned C 6-20 It may be the same as the example of aryl. Specifically, the above C 6-20Aryl amido may be, but is not limited to, N-phenylamido, N-naphthylamido, N-anthracenamido, N-phenyleneamido, or N-pyreneamido.

[0080] In the above alkylamido and arylamido, “amido” means an amino (-NH2) group bonded to a carbonyl group (C=O).

[0081] C above 1-20 Alkylidene may refer to a divalent aliphatic hydrocarbon group in which two hydrogen atoms are removed from one carbon atom of an alkyl group. Specifically, it may be ethylidene, propylidene, isopropylidene, butylidene, pentylidene, etc., but is not limited thereto.

[0082] In one aspect, in the above chemical formulas 1 and 2, a specific example is M 1 and M 2 are different and are each zirconium or hafnium, and X and Y are each halogen or C 1-10 Alkyl, R1 to R 10 Each of these is hydrogen, substituted or unsubstituted C 1-10 Alkyl, a preferred specific example of the present invention is M 1 This zirconium (Zr), M 2 It can be that X is hafnium (Hf), X is chlorine (Cl), and Y is methyl (Me).

[0083] In one aspect, in the above chemical formulas 1 and 2, a specific example is M 1 and M 2 are different and are each zirconium or hafnium, and X and Y are each halogen or C 1-8 Alkyl, R1 to R 10 Each of these is hydrogen, substituted or unsubstituted C 1-8 Alkyl, a preferred specific example of the present invention is M 1 This zirconium (Zr), M 2 It can be that X is hafnium (Hf), X is chlorine (Cl), and Y is methyl (Me).

[0084] In one embodiment, the transition metal compound represented by the chemical formula 1 may be at least one of the transition metal compounds represented by the chemical formulas 1-1 to 1-12 below, and the transition metal compound represented by the chemical formula 2 may be at least one of the transition metal compounds represented by the chemical formulas 2-1 to 2-10 below, but is not limited thereto.

[0085] [Chemical Formula 1-1]

[0086]

[0087] [Chemical Formula 1-2]

[0088]

[0089] [Chemical Formula 1-3]

[0090]

[0091] [Chemical Formula 1-4]

[0092]

[0093] [Chemical Formula 1-5]

[0094]

[0095] [Chemical Formula 1-6]

[0096]

[0097] [Chemical Formula 1-7]

[0098]

[0099] [Chemical Formula 1-8]

[0100]

[0101] [Chemical Formula 1-9]

[0102]

[0103] [Chemical Formula 1-10]

[0104]

[0105] [Chemical Formula 1-11]

[0106]

[0107] [Chemical Formula 1-12]

[0108]

[0109] [Chemical Formula 2-1]

[0110]

[0111] [Chemical Formula 2-2]

[0112]

[0113] [Chemical Formula 2-3]

[0114]

[0115] [Chemical Formula 2-4]

[0116]

[0117] [Chemical Formula 2-5]

[0118]

[0119] [Chemical Formula 2-6]

[0120]

[0121] [Chemical Formula 2-7]

[0122]

[0123] [Chemical Formula 2-8]

[0124]

[0125] [Chemical Formula 2-9]

[0126]

[0127] [Chemical Formula 2-10]

[0128]

[0129] In one embodiment, the hybrid metallocene catalyst may include a weight ratio of the transition metal compound represented by the chemical formula 1 to the transition metal compound represented by the chemical formula 2 of 5 to 95:95 to 5.

[0130] In one embodiment, the hybrid metallocene catalyst may include a weight ratio of the transition metal compound represented by the chemical formula 1 to the transition metal compound represented by the chemical formula 2 of 7 to 20:80 to 93, or 10 to 15:75 to 90, but is not limited thereto.

[0131] In one aspect, the hybrid metallocene catalyst may be a supported catalyst in which a transition metal compound and a cocatalyst are supported on a support.

[0132] In one embodiment, the cocatalyst may be one or more selected from the group consisting of compounds represented by the following chemical formulas 3 to 5.

[0133] [Chemical Formula 3]

[0134]

[0135] [Chemical Formula 4]

[0136]

[0137] [Chemical Formula 5]

[0138] [LH] + [Z(A)4] - or [L] + [Z(A)4] -

[0139] In the above chemical formulas 3 to 5,

[0140] n is an integer greater than or equal to 2, and R 11 Silver halogen, C 1-20 C substituted with an alkyl group or halogen 1-20 is an alkyl group,

[0141] D is aluminum (Al) or boron (B), and R 12 , R 13 and R 14 are each independently halogen, C 1-20 C, a straight or branched chain alkyl group, substituted with halogen 1-20 alkyl group or C 1-20 is an alkoxy group,

[0142] L is a neutral or cationic Lewis base, [LH] + and [L] + is a Bronsted acid, Z is a group 13 element, and A is C 6-20 Aryl group of or C 1-20 is an alkyl group.

[0143] The cocatalyst compound represented by the above chemical formula 3 may be an alkylaluminoxane, and examples thereof include, but are not limited to, methylaluminoxane, ethylaluminoxane, isobutylaluminoxane, butylaluminoxane, etc.

[0144] The cocatalyst compound represented by the above chemical formula 4 may be an organoaluminum or boron compound, and may be, for example, trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, dimethylchloroaluminum, triisopropylaluminum, tri-s-butylaluminum, tricyclopentylaluminum, tripentylaluminum, triisopentylaluminum, trihexylaluminum, trioctylaluminum, ethyldimethylaluminum, methyldiethylaluminum, triphenylaluminum, tri-p-tolylaluminum, dimethylaluminum methoxide, dimethylaluminum ethoxide, trimethylboron, triethylboron, triisobutylboron, tripropylboron, tributylboron, etc., but is not limited thereto.

[0145] The co-catalyst compound represented by the above chemical formula 5 may be a compound in which a cation such as ammonium, phosphonium, anilinium, or carbonium is combined with an organometallic compound having boron or aluminum as a central metal, and examples thereof include triethylammonium tetraphenylboron, tributylammonium tetraphenylboron, trimethylammonium tetraphenylboron, tripropylammonium tetraphenylboron, trimethylammonium tetra(p-tolyl)boron, trimethylammonium tetra(o,p-dimethylphenyl)boron, tributylammonium tetra(p-trifluoromethylphenyl)boron, trimethylammonium tetra(p-trifluoromethylphenyl)boron, tributylammonium tetrapentafluorophenylboron, N,N-diethylanilinium tetraphenylboron, N,N-diethylanilinium tetrapentafluorophenylboron, Diethylammonium tetrapentafluorophenylboron, triphenylphosphonium tetraphenylboron, trimethylphosphonium tetraphenylboron, triethylammonium tetraphenylaluminum, tributylammonium tetraphenylaluminum, trimethylammonium tetraphenylaluminum, tripropylammonium tetraphenylaluminum, trimethylammonium tetra(p-tolyl)aluminum, tripropylammonium tetra(p-tolyl)aluminum, triethylammonium tetra(o,p-dimethylphenyl)aluminum, tributylammonium tetra(p-trifluoromethylphenyl)aluminum, trimethylammonium tetra(p-trifluoromethylphenyl)aluminum, tributylammonium tetrapentafluorophenylaluminum, N,N-diethylanilinium tetraphenylaluminum, N,N-diethylanilinium tetrapentafluorophenylaluminum, Diethylammonium tetrapentatetraphenylaluminum, triphenylphosphonium tetraphenylaluminum, trimethylphosphonium tetraphenylaluminum, tripropylammonium tetra(p-tolyl)boron, triethylammonium tetra(o,p-dimethylphenyl)boron, tributylammonium tetra(p-trifluoromethylphenyl)boron, triphenylcarbonium tetra(p-trifluoromethylphenyl)boron, triphenylcarbonium tetrapentafluorophenylboron, etc., but are not limited thereto.

[0146] In one embodiment, the support may be capable of supporting both a transition metal compound and a cocatalyst compound, and may include a material containing a hydroxyl group on its surface. Specifically, a material having a hydroxyl group and a siloxane group on its surface, from which moisture is removed, and thus having enhanced reactivity, may be used.

[0147] The support may be, for example, one or a mixture of two or more selected from the group consisting of silica, aluminum oxide, and magnesium oxide. Specifically, silica, silica-alumina, and silica-magnesia dried at high temperature may be used as the support, and these may typically contain oxides, carbonates, sulfates, and nitrates such as Na2O, K2CO3, BaSO4, and Mg(NO3)2. In addition, these may include carbon, zeolite, magnesium chloride, and the like. However, the support is not limited to these, and is not particularly limited as long as it can support a transition metal compound and a cocatalyst compound.

[0148] The average particle size of the above-mentioned carrier may be 10 to 250 μm, preferably 10 to 150 μm, and more preferably 20 to 100 μm, but is not limited thereto.

[0149] The micropore volume of the above-mentioned carrier is 0.1 to 10 cm 3 / g, preferably 0.5 to 5 cm 3 / g, better 1.0 to 3.0 cm 3 / g may be, but is not limited to.

[0150] The specific surface area of ​​the above-mentioned carrier may be, but is not limited to, 1 to 1,000 m2 / g, preferably 100 to 800 m2 / g, and more preferably 200 to 600 m2 / g.

[0151] In one embodiment, the α-olefin is C 4-20 , or better yet, C 4-12It may be an α-olefin. The α-olefin may be, for example, one or a mixture of two or more selected from the group consisting of 1-butene, 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-itocene, 4,4-dimethyl-1-pentene, 4,4-diethyl-1-hexene, and 3,4-dimethyl-1-hexene, but is not limited thereto. As a specific example, the α-olefin may be 1-hexene, but is not necessarily limited thereto.

[0152] In one aspect, the concentration ratio of α-olefin to ethylene (R H ) may be 0.65 or more, for example, 0.65 to 0.85, 0.70 to 0.80, 0.75 to 0.77, and the concentration % ratio of α-olefin to ethylene in the above range (R H ) can be processed by biaxial stretching, and can have excellent transparency after biaxial stretching, thereby better achieving the purpose of the present invention.

[0153] In addition, the crystallinity (X) of the above concentration% ratio range satisfies the following equation 1 c ) can be controlled to polymerize, thereby better achieving the purpose of the present invention.

[0154] [Formula 1]

[0155] -100R H + 116.2 <X c <-100R H +118.2

[0156] In one aspect, the concentration % ratio may be a ratio measured by gas chromatography (GC). For example, the concentration % ratio of α-olefin to ethylene (R H ) may be the value obtained by dividing the mol% concentration of α-olefin measured in GC by the mol% concentration of ethylene.

[0157] In one embodiment, the method for producing low-density polyethylene may be a method for continuously polymerizing ethylene and α-olefin in a fluidized bed reactor, and one or two or more fluidized bed reactors may be provided in series.

[0158] In one embodiment, the low-density polyethylene manufacturing method may be a method of polymerizing ethylene and α-olefin at a temperature of 70 to 90° C., or more preferably, 80 to 85° C. Under the temperature conditions of the above range, the concentration ratio (R) of α-olefin to ethylene H ) may be capable of manufacturing low-density polyethylene with a density of 0.65 to 0.85. In addition, the manufactured low-density polyethylene is capable of biaxial stretching processing and has excellent transparency after biaxial stretching processing, which is preferred, but is not limited thereto.

[0159] In one aspect, the above low-density polyethylene manufacturing method has a crystallinity (X) satisfying the following equation 1 c ) can be adjusted to polymerize.

[0160] [Formula 1]

[0161] -100R H + 116.2 <X c <-100R H +118.2

[0162] In the above equation 1, R H is the concentration ratio of α-olefin to ethylene, and 0.65≤R H ≤0.85.

[0163] Low-density polyethylene manufactured by polymerization while controlling the crystallinity satisfying the above formula 1 can be processed by biaxial stretching, and is preferred because it can have excellent transparency after biaxial stretching processing, but is not limited thereto.

[0164] The crystallinity may have a value of, for example, 35 to 55%, preferably 40 to 50%, and more preferably 40 to 45%, and the low-density polyethylene manufactured by polymerization while controlling the crystallinity within the above range can be subjected to biaxial stretching processing and can have excellent transparency after biaxial stretching processing, which is preferred, but is not limited thereto.

[0165] Another aspect of the present invention is a low-density polyethylene resin polymerized with ethylene and α-olefin under a hybrid metallocene catalyst comprising a transition metal compound represented by the following chemical formulas 1 and 2, wherein the crystallinity (X) of the low-density polyethylene resin c ) provides a low-density polyethylene resin that satisfies the following equation 1.

[0166] [Formula 1]

[0167] -100R H + 116.2 <X c <-100R H +118.2

[0168] In the above equation 1, R H is the concentration ratio of α-olefin to ethylene, and 0.65≤R H ≤0.85.

[0169] [Chemical Formula 1]

[0170]

[0171] [Chemical Formula 2]

[0172]

[0173] In the above chemical formulas 1 and 2, M 1 and M 2 are each independently titanium (Ti), zirconium (Zr) or hafnium (Hf), and X and Y are each independently halogen, C 1-20 Alkyl, C 2-20 Alkenyl, C 2-20 alkynyl, C 6-20 Aryl, C 1-20 Alkyl C 6-20Aryl, C 6-20 Aryl C 1-20 Alkyl, C 1-20 Alkylamido, C 6-20 Arylamido or C 1-20 It is alkylidene,

[0174] R1 to R 10 are each independently hydrogen, substituted or unsubstituted C 1-20 Alkyl, substituted or unsubstituted C 2-20 Alkenyl, substituted or unsubstituted C 6-20 Aryl, substituted or unsubstituted C 1-20 Alkyl C 6-20 Aryl, substituted or unsubstituted C 6-20 Aryl C 1-20 Alkyl, substituted or unsubstituted C 1-20 Heteroalkyl, substituted or unsubstituted C 3-20 Heteroaryl, substituted or unsubstituted C 1-20 Alkylamido, substituted or unsubstituted C 6-20 Arylamido, substituted or unsubstituted C 1-20 Alkylidene, or substituted or unsubstituted C 1-20 It is a cylinder, R1 to R 10 Each independently adjacent group is connected to form a substituted or unsubstituted saturated or unsaturated C 4-20 It can form a ring.

[0175] The contents of the above chemical formulas 1 and 2 are the same as those described above, so their description is omitted.

[0176] In one aspect, the crystallinity (X) satisfying the above formula 1 c ) can be applied as a base layer of packaging materials because it has appropriate rigidity and toughness and excellent biaxial stretching processability. In addition, it can be used to manufacture single-material packaging materials. The crystallinity may have a value of, for example, 35 to 55%, preferably 40 to 50%, and more preferably 40 to 45%, but is not limited thereto.

[0177] In one embodiment, the low-density polyethylene resin can be biaxially stretched, and can be stretched 4 to 6 times in the machine direction (MD) and 4 to 10 times in the transverse direction (TD) at a speed of 3 cm / s, with a low-density polyethylene having a width of 10 cm, a length of 10 cm, and a thickness of 1 mm. When the low-density polyethylene resin is biaxially stretched, the optical properties and transparency can be improved, and the impact resistance and stiffness can be improved, so that the low-density polyethylene resin can be applied as a base layer of a packaging material.

[0178] Furthermore, if the film formation is uneven during biaxial stretching of polyethylene, its application to products is difficult. Therefore, when the low-density polyethylene resin is stretched evenly in both directions during biaxial stretching, opaque lines are not formed, and stretching defects due to breakage do not occur, it may be advantageous for application as a packaging material base layer.

[0179] In one embodiment, the biaxial stretching process may be performed by manufacturing a 10 cm × 10 cm, 1 mm sheet using a compressor using the low-density polyethylene resin, and then heating the manufactured sheet in an oven at 120 to 125° C. for 200 to 500 seconds, stretching it in MD at a speed of 3 cm / s, and then stretching it in TD.

[0180] The thickness of the film after the above biaxial stretching process may be 10 to 50 ㎛, preferably 15 to 30 ㎛, and more preferably 20 to 25 ㎛, and a film within the above thickness range is preferred as a packaging material base layer because it can have excellent strength, toughness, and transparency, but is not limited thereto.

[0181] In one embodiment, the melt index (MI) of the low-density polyethylene resin measured at 190° C. under a load of 2.16 kg may be 0.50 to 1.50 g / 10 min, preferably 0.60 to 1.25 g / 10 min, and more preferably 0.65 to 1.10 g / 10 min. A low-density polyethylene resin having a melt index in the above range is preferred because it has excellent biaxial stretching processability, but is not limited thereto.

[0182] In one embodiment, the melt index (MI) of the low-density polyethylene resin measured at 190° C. under a load of 21.6 kg may be 10 to 30 g / 10 min, preferably 10 to 25 g / 10 min, and more preferably 13 to 25 g / 10 min. A low-density polyethylene resin having a melt index in the above range is preferred because it has excellent biaxial stretching processability, but is not limited thereto.

[0183] In one embodiment, the melt flow rate (MFR) of the low-density polyethylene resin measured at 190° C. according to ASTM D1238 may be 15 to 30 g / 10 min, preferably 18 to 25 g / 10 min, and more preferably 19 to 25 g / 10 min, and a low-density polyethylene resin having a melt flow rate in the above range is preferred due to its superior biaxial stretching processability, but is not limited thereto. The MFR is a value calculated by MI(21.6 kg) / MI(2.16 kg)=MFR at 190° C. under a load of 21.6 and a load of 2.16 of the low-density polyethylene resin.

[0184] In one embodiment, the density of the low-density polyethylene resin is 0.900 to 0.945 g / cm 3, preferably 0.910 to 0.935, and even better 0.915 to 0.930, and a low-density polyethylene resin having a density in the above range is preferred because it has excellent biaxial stretching processability and can have excellent transparency after biaxial stretching processing, but is not limited thereto.

[0185] In one embodiment, the number average molecular weight of the low-density polyethylene may be 15,000 to 50,000 g / mol, preferably 18,000 to 40,000 g / mol, and more preferably 19,000 to 30,000 g / mol. A low-density polyethylene resin having a number average molecular weight within the above range may have excellent mechanical properties and flowability, thus facilitating biaxial stretching processing, and may have excellent transparency after biaxial stretching processing, and is therefore preferred, but is not limited thereto.

[0186] In one embodiment, the weight average molecular weight of the low-density polyethylene may be 100,000 to 300,000 g / mol, preferably 110,000 to 200,000 g / mol, and more preferably 110,000 to 180,000 g / mol. A low-density polyethylene resin having a weight average molecular weight within the above range may have excellent strength and toughness, and may be applied as a packaging material base layer material, and may be easily subjected to biaxial stretching processing and may have excellent transparency after biaxial stretching processing, and is therefore preferred, but is not limited thereto.

[0187] In one embodiment, the z-average molecular weight of the low-density polyethylene may be 350,000 to 370,000 g / mol, more preferably 351,000 to 369,000 g / mol. A low-density polyethylene resin having a z-average molecular weight within the above range may have excellent strength and toughness, and thus may be preferred as a packaging material base material. However, if the z-average molecular weight is too high, processability may be poor, making biaxial stretching impossible, and thus, a low-density polyethylene having an appropriate z-average molecular weight must be produced.

[0188] In one embodiment, the polydispersity index (PDI) of the low-density polyethylene resin may be 5.0 to 6.0, or better, 5.5 to 5.9.

[0189] In one aspect, the melting temperature (T) of the low-density polyethylene m ) may be 120 to 130 ℃, or better, 120 to 125 ℃, and low-density polyethylene in the above melting temperature range may have excellent biaxial stretching processability, and may also be advantageous in terms of cost.

[0190] In one aspect, the crystallization temperature (T) of the low-density polyethylene c ) may be 100 to 120°C, or better, 110 to 115°C, and low-density polyethylene in the above crystallization temperature range is preferred because it has excellent thermal properties and can be processable, but is not limited thereto.

[0191] Another aspect of the present invention provides a low-density polyethylene film comprising the low-density polyethylene resin.

[0192] In one embodiment, the haze of the low-density polyethylene film according to ASTM D 1003 is not particularly limited to a lower limit, but may be 5 to 20%, 10 to 20%, 13 to 20%, 13 to 18%, or 14 to 16%. A low-density polyethylene film within the haze range is preferred because it can have excellent optical properties, but is not limited thereto.

[0193] Another aspect of the present invention provides a packaging material made from the low-density polyethylene film.

[0194] In one aspect, the packaging material may be a single-material packaging material in which the substrate layer, which was conventionally made of polyethylene terephthalate, nylon, polyamide, etc., is replaced with a low-density polyethylene film according to one aspect of the present invention.

[0195] The present invention will be described in more detail based on the following examples and comparative examples. However, the following examples and comparative examples are merely illustrative examples for further explaining the present invention, and the present invention is not limited by the following examples and comparative examples.

[0196] [measurement method]

[0197] 1. Concentration ratio of α-olefin to ethylene (R) H ) measurement method

[0198] The molar concentration of ethylene and α-olefin was measured using gas chromatography (PGC5000; ABB) and the concentration % ratio (R) was calculated using the following formula. H ) was calculated. At this time, the carrier gas of the gas chromatography column was hydrogen, and the temperature condition was measured at 190 ℃.

[0199] [Calculation formula]

[0200] Concentration % ratio (R H ) = α-olefin molar concentration (mol%) / ethylene molar concentration (mol%)

[0201] 2. Measurement of melt index (MI) and melt flow rate (MFR)

[0202] The melt index and melt flow rate of low-density polyethylene resin were measured under load conditions of 2.16 kg and 21.6 kg at 190 °C according to ASTM D1238.

[0203] 3. Density measurement

[0204] The density of low-density polyethylene resin was measured according to ASTM D1505.

[0205] 4. Measurement of number average molecular weight, weight average molecular weight, and z-average molecular weight

[0206] Measurements were made at 160°C using GPC-FTIR (GPC-6; Polymer char) equipment, using PL gel Olexis as the column, polystyrene as the standard material, and trichlorobenzene as the solvent.

[0207] 5. Melting temperature (T m ) and crystallization temperature (T c ) measurement

[0208] Measurements were made using a differential scanning calorimeter (DSC2920; TA instrument). Specifically, the polymer was heated to 200°C, maintained at that temperature for 5 minutes, cooled to 20°C, and then increased again, with the temperature rising and falling rates each controlled to 20°C / min.

[0209] 6. Crystallinity measurement

[0210] The heat of fusion (H) was calculated by measuring the enthalpy value of low-density polyethylene resin using a differential scanning calorimeter (DSC2920; TA instrument). f ) was divided by 290.37 J / g (theoretical heat of fusion of low-density polyethylene) and then multiplied by 100 (%) to calculate.

[0211] Crystallinity (%) =

[0212] 7. Biaxial stretching processing

[0213] A low-density polyethylene sheet measuring 10 cm in width, 10 cm in length, and 1 mm in thickness was manufactured at 190°C using a compressor, and then heated in an oven at 120 to 125°C for 300 seconds. Thereafter, the sheet was stretched in the machine direction (MD) at a speed of 3 cm / s and then in the transverse direction (TD) using a biaxial stretching device (PS002; SDB).

[0214] 8. Haze Measurement

[0215] According to ASTM D 1003, a biaxially stretched film specimen with a thickness of 20 ㎛ was measured five times and the average value was reported.

[0216] 9. Film thickness measurement

[0217] According to ASTM D 4417, the film thickness was measured 10 times using a film measuring device (SP-SP1570; TQC) and the average value was used.

[0218] [Example of preparing a hybrid metallocene catalyst]

[0219] [Chemical Formula 1-1]

[0220]

[0221] [Chemical Formula 2-1]

[0222]

[0223] In a glove box, 0.57 g of the transition metal compound represented by the above chemical formula 1-1 and 5.39 g of the transition metal compound represented by the chemical formula 2-1 were stirred with 890 g of a solution containing 10 wt% methylaluminoxane in toluene for 1 hour at room temperature (23°C) to prepare a transition metal compound solution.

[0224] After adding 50 ml of purified toluene to 210 g of silica (XPO-2402) to prepare a silica slurry, the transition metal compound solution was injected and stirred in an oil bath at 75°C for 3 hours to prepare a metallocene catalyst solution. The metallocene catalyst solution was separated into solid and liquid, the supernatant was removed, and only the metallocene catalyst was isolated. The metallocene catalyst was washed three times with toluene and dried in a vacuum at 30°C for 10 hours to obtain 300 g of a hybrid supported catalyst in the form of a free-flowing powder.

[0225] [Examples and Comparative Examples]

[0226] Continuous gas phase polymerization of ethylene and 1-hexene was performed at 80°C in a fluidized bed reactor using the catalyst prepared in Manufacturing Example 1. The reaction conditions of Examples 1 to 2 and Comparative Examples 1 to 4 are described in Table 1 below.

[0227] Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Catalyst Manufacturing Example 1 Manufacturing Example 1 - Manufacturing Example 1 Manufacturing Example 1 Manufacturing Example 1 Polymerization temperature (℃) 80 80 81 80 80 80 Catalyst injection amount (g / h) 0.90 1.20 1.00 1.40 1.50 1.00 Hydrogen injection amount (g / h) 0.57 2.17 1.35 0.70 1.30 1.40 1 - Hexene injection amount (g / h) 70 4 16 6 0 6 0 7 7 5 0 6 5 1 Hydrogen / ethylene concentration % ratio 0.02 0.03 0.02 0.02 0.02 1 - Hexene / ethylene concentration % ratio (R H )0.770.760.610.440.310.64Production per hour (kg / h)9.616.798.044.935.218.30

[0228] Table 2 below shows the measured properties of polyethylene manufactured by polymerizing ethylene / 1-hexene in examples and comparative examples. In Table 2 below, "impossible" indicates a case where the elongation length could not be measured due to fracture during elongation.

[0229] Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 MI (2.16 kg, 190℃) 0.68 1.03 0.89 0.65 1.31 0.79 MFI (21.6 kg, 190℃) 13.44 24.55 17.98 11.54 21.81 14.99 MFR 19.76 23.84 20.20 17.75 16.65 18.97 Density (g / mL) 0.92 75 0.91 87 0.92 76 0.94 43 0.94 43 0.92 9 3 M z 368300351000316000315700243500311500M n 295001920026600266002280023900M w 163300112000110000144100117600140900PDI5.535.834.145.415.155.9T m (℃)124.4123.2124.2132.8131.7127.4T c (℃)111.5110.2110.4116.4116.1114.3X c(%)40.241.259.264.563.451.9MD(x) × TD(x)5×85×8ImpossibleImpossibleImpossibleImpossibleThickness (㎛)2220ImpossibleImpossibleImpossibleImpossibleHaze (%)14.615.1ImpossibleImpossibleImpossibleImpossible

[0230] In the above Tables 1 and 2, it was confirmed that the polyethylene of Examples 1 and 2 manufactured with a concentration % ratio of ethylene / 1-hexene in the range of 0.75 to 0.77% was polymerized while satisfying an appropriate crystallinity (40 to 42%) and z-average molecular weight, and that not only was biaxial stretching possible at 5×8 (MD × TD), but also had excellent optical properties with a Haze value of about 15% or less.

[0231] As described above, the present invention has been described through specific matters and limited examples, but these are provided only to help a more general understanding of the present invention, and the present invention is not limited to the above examples, and those skilled in the art to which the present invention pertains can make various modifications and variations based on this description.

[0232] Therefore, the idea of ​​the present invention should not be limited to the described embodiments, and all things that are equivalent or equivalent to the following claims as well as the claims are considered to fall within the scope of the idea of ​​the present invention.

Claims

1. A method for producing low-density polyethylene by polymerizing ethylene and α-olefin (alpha-olefin) under a hybrid metallocene catalyst including a transition metal compound represented by the following chemical formula 1 and chemical formula 2, wherein the concentration ratio (R) of α-olefin to ethylene H ) to 0.65 to 0.

85. [Chemical Formula 1] [Chemical Formula 2] In the above chemical formulas 1 and 2, M 1 and M 2 are each independently titanium (Ti), zirconium (Zr) or hafnium (Hf), and X and Y are each independently halogen, C 1-20 Alkyl, C 2-20 Alkenyl, C 2-20 alkynyl, C 6-20 Aryl, C 1-20 Alkyl C 6-20 Aryl, C 6-20 Aryl C 1-20 Alkyl, C 1-20 Alkylamido, C 6-20 Arylamido or C 1-20 It is alkylidene, R1 to R 10 are each independently hydrogen, substituted or unsubstituted C 1-20 Alkyl, substituted or unsubstituted C 2-20 Alkenyl, substituted or unsubstituted C 6-20 Aryl, substituted or unsubstituted C 1-20 Alkyl C 6-20 Aryl, substituted or unsubstituted C 6-20 Aryl C 1-20 Alkyl, substituted or unsubstituted C 1-20 Heteroalkyl, substituted or unsubstituted C 3-20 Heteroaryl, substituted or unsubstituted C 1-20 Alkylamido, substituted or unsubstituted C 6-20 Arylamido, substituted or unsubstituted C 1-20 Alkylidene, or substituted or unsubstituted C 1-20 It is a cylinder, R1 to R 10 Each independently adjacent group is connected to form a substituted or unsubstituted saturated or unsaturated C 4-20 It can form a ring.

2. In paragraph 1, The above α-olefin is C 4-20 A method for producing low-density polyethylene which is an α-olefin.

3. In paragraph 1, A method for producing low-density polyethylene, wherein the above hybrid metallocene catalyst is a supported catalyst in which a transition metal compound and a cocatalyst are supported on a support.

4. In paragraph 3, A method for producing low-density polyethylene, wherein the cocatalyst is one or more selected from the group consisting of compounds represented by the following chemical formulas 3 to 5. [Chemical Formula 3] [Chemical Formula 4] [Chemical Formula 5] [LH] + [Z(A)4] - or [L] + [Z(A)4] - In the above chemical formulas 3 to 5, n is an integer greater than or equal to 2, and R 11 Silver halogen, C 1-20 C substituted with an alkyl group or halogen 1-20 is an alkyl group, D is aluminum (Al) or boron (B), and R 12 , R 13 and R 14 are each independently halogen, C 1-20 C, a straight or branched chain alkyl group, substituted with halogen 1-20 alkyl group or C 1-20 is an alkoxy group, L is a neutral or cationic Lewis base, [LH] + and [L] + is a Bronsted acid, Z is a group 13 element, and A is C 6-20 Aryl group of or C 1-20 is an alkyl group.

5. In paragraph 3, A method for producing low-density polyethylene, wherein the carrier is one or a mixture of two or more selected from the group consisting of silica, aluminum oxide, and magnesium oxide.

6. In paragraph 1, The above low-density polyethylene manufacturing method is a low-density polyethylene manufacturing method in which ethylene and α-olefin are continuously subjected to a gas phase polymerization reaction in a fluidized bed reactor.

7. In paragraph 1, The above low-density polyethylene manufacturing method is a low-density polyethylene manufacturing method in which ethylene and α-olefin are polymerized at a temperature of 70 to 90°C.

8. In paragraph 1, The above low-density polyethylene manufacturing method satisfies the following formula 1 and has a crystallinity (X) c ) and polymerization. [Formula 1] -100R H + 116.2 <X c <-100R H +118.2 In the above equation 1, R H is the concentration ratio of α-olefin to ethylene, and 0.65≤R H ≤0.

85.

9. A low-density polyethylene resin polymerized with ethylene and α-olefin under a hybrid metallocene catalyst including a transition metal compound represented by the following chemical formulas 1 and 2, wherein the crystallinity (X) of the low-density polyethylene resin c ) A low-density polyethylene resin satisfying the following equation 1. [Formula 1] -100R H + 116.2 <X c <-100R H +118.2 In the above equation 1, R H is the concentration ratio of α-olefin to ethylene, and 0.65≤R H ≤0.

85. [Chemical Formula 1] [Chemical Formula 2] In the above chemical formulas 1 and 2, M 1 and M 2 are each independently titanium (Ti), zirconium (Zr) or hafnium (Hf), and X and Y are each independently halogen, C 1-20 Alkyl, C 2-20 Alkenyl, C 2-20 alkynyl, C 6-20 Aryl, C 1-20 Alkyl C 6-20 Aryl, C 6-20 Aryl C 1-20 Alkyl, C 1-20 Alkylamido, C 6-20 Arylamido or C 1-20 It is alkylidene, R1 to R 10 are each independently hydrogen, substituted or unsubstituted C 1-20 Alkyl, substituted or unsubstituted C 2-20 Alkenyl, substituted or unsubstituted C 6-20 Aryl, substituted or unsubstituted C 1-20 Alkyl C 6-20 Aryl, substituted or unsubstituted C 6-20 Aryl C 1-20 Alkyl, substituted or unsubstituted C 1-20 Heteroalkyl, substituted or unsubstituted C 3-20 Heteroaryl, substituted or unsubstituted C 1-20 Alkylamido, substituted or unsubstituted C 6-20 Arylamido, substituted or unsubstituted C 1-20 Alkylidene, or substituted or unsubstituted C 1-20 It is a cylinder, R1 to R 10 Each independently adjacent group is connected to form a substituted or unsubstituted saturated or unsaturated C 4-20 It can form a ring.

10. In paragraph 9, The above low-density polyethylene resin is capable of biaxial stretching processing, and is a low-density polyethylene resin that can stretch a low-density polyethylene having a width of 10 cm, a length of 10 cm, and a thickness of 1 mm by at least four times in the longitudinal direction (MD; machine direction) and at least four times in the transverse direction (TD; transverse direction) at a speed of 3 cm / s.

11. In paragraph 9, A low-density polyethylene resin having a melt index (MI) of 0.50 to 1.50 g / 10 min, measured at 190° C. under a load of 2.16 kg according to ASTM D1238.

12. In paragraph 9, A low-density polyethylene resin having a melt index (MI) of 10 to 30 g / 10 min, measured at 190°C under a load of 21.6 kg according to ASTM D1238.

13. In paragraph 9, A low-density polyethylene resin having a melt flow rate (MFR) of 15 to 30 g / 10 min as measured at 190°C according to ASTM D1238.

14. In paragraph 9, The density of the above low-density polyethylene resin is 0.945 g / cm 3 Low density polyethylene resin having the following properties:

15. In paragraph 9, A low-density polyethylene resin having a number average molecular weight of 15,000 to 50,000 g / mol.

16. In paragraph 9, A low-density polyethylene resin having a weight average molecular weight of 100,000 to 300,000 g / mol.

17. In paragraph 9, A low-density polyethylene resin having a z-average molecular weight of 350,000 g / mol or more.

18. In paragraph 9, Melting temperature (T) of the above low-density polyethylene resin m ) is a low-density polyethylene resin having a temperature of 120 to 130°C.

19. A low-density polyethylene film comprising a low-density polyethylene resin selected from any one of claims 9 to 18.

20. In paragraph 19, A low-density polyethylene film having a haze of 20% or less according to ASTM D 1003.

21. A packaging material manufactured from a low-density polyethylene film containing a low-density polyethylene resin selected from any one of claims 9 to 18.

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