KR20230059020A - High density polyethylene and film comprising the same - Google Patents

Abstract

High-density polyethylene according to the present invention enables, when processing a film, both processability and moisture barrier properties to be improved without deteriorating physical properties without blending with LDPE through fine control of the ratios of weight average molecular weight, number average molecular weight, and Z-average molecular weight along with high density. In the high-density polyethylene, the molecular weight distribution (Mw/Mn) is 4.5 or less, the ratio of Mz (Z-average molecular weight) to Mw (weight average molecular weight) (Mz/Mw) of 2.8 or less, and the density measured according to ASTM D 1505 is 0.960 g/cm^3 to 0.975 g/cm^3.

Description

High-density polyethylene and a film containing the same {HIGH DENSITY POLYETHYLENE AND FILM COMPRISING THE SAME}

The present invention relates to high-density polyethylene having excellent water barrier properties during film processing and a film comprising the same.

Polyethylene is a general-purpose polymer widely used for various purposes such as packaging films, pipes, bottles, and containers, and is classified into high-density polyethylene (HDPE), low-density polyethylene (LDPE), and linear low-density polyethylene (LLDPE) according to density.

Recently, in order to increase the recycling rate of food packaging materials and pouches, instead of aluminum foil, nylon, or polyethylene terephthalate (PET), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), The use of polyethylene films (All-PE films) such as density polyethylene (MDPE) and high density polyethylene (HDPE) is increasing.

Among them, in order to use HDPE in a food packaging film, transparency improvement is required to confirm the freshness and condition of food. To this end, a method of mixing and using low-density polyethylene such as LLDPE has been proposed, but in this case, the density of the film is lowered, resulting in a decrease in stiffness or tear strength of the film.

In addition, in order to facilitate recycling, the moisture and oxygen transmission barrier properties of the polyethylene film (All-PE film) should be increased. Among polyethylene, HDPE has the highest density and many crystalline regions, so it is more advantageous in blocking the movement path of oxygen or moisture. Accordingly, HDPE may serve as a barrier film that blocks moisture and oxygen permeation. However, HDPE has a disadvantage in that the film moisture barrier property (WVTR, water vapor transmission rate, mg/m ² ·day) is higher than that of conventionally used aluminum foil or nylon.

Accordingly, in order to increase the recycling rate of food packaging materials and pouches, it is necessary to develop a method capable of improving processability and water barrier properties (WVTR) without deteriorating mechanical properties of films using HDPE.

The present invention is intended to provide high-density polyethylene capable of improving processability and moisture barrier properties without deterioration of film properties.

In addition, the present invention is to provide a film capable of exhibiting excellent processability and moisture barrier properties without deterioration of physical properties by manufacturing using the above-described high-density polyethylene.

According to one embodiment of the invention, the molecular weight distribution (Mw/Mn) is 4.5 or less, the ratio of Mz (Z-average molecular weight) to Mw (weight average molecular weight) (Mz/Mw) is 2.8 or less, and ASTM D 1505 A high-density polyethylene having a density of 0.960 g/cm 3 to 0.975 g/cm 3 as measured according to

In addition, the high-density polyethylene is characterized in that it is produced by a bimodal homopolymerization process in the presence of a metallocene catalyst containing only a metallocene compound represented by Formula 1 as a catalytically active component.

[Formula 1]

(Cp ¹ R ^a ) _n (Cp ² R ^b )M ¹ Z ¹ _3-n

In Formula 1,

M ¹ is a Group 4 transition metal;

Cp ¹ and Cp ² are the same as or different from each other, and are each independently selected from the group consisting of cyclopentadienyl, indenyl, 4,5,6,7-tetrahydro-1-indenyl, and fluorenyl radicals. one, which may be substituted with a hydrocarbon having 1 to 20 carbon atoms;

R ^a and R ^b are the same as or different from each other, and are each independently hydrogen, C _1-20 alkyl, C _1-10 alkoxy, C _2-20 alkoxyalkyl, C _6-20 aryl, C _6-10 aryloxy, C _2-20 alkenyl, C _7-40 alkylaryl, C _7-40 arylalkyl, C _8-40 arylalkenyl, or C _2-10 alkynyl;

Z ¹ is a halogen atom, C _1-20 alkyl, C _2-10 alkenyl, C _7-40 alkylaryl, C _7-40 arylalkyl, C _6-20 aryl, substituted or unsubstituted C _1-20 alkylidene , substituted or unsubstituted amino, C _2-20 alkylalkoxy, or C _7-40 arylalkoxy; and

n is 1 or 0;

In addition, the present invention provides a film comprising the high-density polyethylene.

According to the present invention, it is possible to improve both processability and moisture barrier properties without deterioration of physical properties during film processing through fine adjustment of the ratio of weight average molecular weight, number average molecular weight, and Z-average molecular weight together with high density of polyethylene (HDPE). can

1 is a schematic diagram showing an apparatus and process for producing high-density polyethylene according to an embodiment of the present invention by way of example.

In the present invention, terms such as first and second are used to describe various components, and the terms are used only for the purpose of distinguishing one component from another.

In addition, terms used in this specification are only used to describe exemplary embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as "comprise", "comprise" or "having" are intended to indicate that there is an embodied feature, number, step, component, or combination thereof, but one or more other features or It should be understood that the presence or addition of numbers, steps, components, or combinations thereof is not precluded.

Also, as used throughout this specification, the terms "about", "substantially" and the like are used at or approximating that value when manufacturing and material tolerances inherent in the stated meaning are given, and Exact or absolute figures are used as an aid to understanding and to prevent exploitation by unscrupulous infringers of the disclosed disclosure.

In addition, in the present specification, “part by weight” refers to a relative concept expressed as a ratio of the weight of a material relative to the weight of a material. For example, in a mixture in which the weight of substance A is 50 g, the weight of substance B is 20 g, and the weight of substance C is 30 g, the amounts of substance B and substance C based on 100 parts by weight of substance A are 40, respectively. parts by weight and 60 parts by weight.

In addition, "% by weight" means an absolute concept expressed as a percentage of the weight of a certain material out of the total weight. In the above example mixture, the contents of substance A, substance B, and substance C are 50% by weight, 20% by weight, and 30% by weight, respectively, based on 100% of the total weight of the mixture. At this time, the total content of each component does not exceed 100% by weight.

Since the present invention can have various changes and various forms, specific embodiments will be exemplified and described in detail below. However, it should be understood that this is not intended to limit the present invention to the specific disclosed form, and includes all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Hereinafter, the present invention will be described in more detail.

According to one embodiment of the invention, through fine adjustment of the ratio of weight average molecular weight, number average molecular weight, and Z-average molecular weight with high density, excellent processability and moisture barrier properties can be simultaneously improved without deterioration of physical properties during film processing. High-density polyethylene is provided.

Specifically, the high-density polyethylene of the present invention has a molecular weight distribution (Mw/Mn) of 4.5 or less, a ratio of Mz (Z-average molecular weight) to Mw (weight average molecular weight) (Mz/Mw) of 2.8 or less, and ASTM D 1505 The density measured according to is 0.960 to 0.975 g/cm 3 .

In particular, in the present invention, high-density polyethylene is produced by a bimodal homopolymerization process using only two reactors (CSTR) and is characterized in that it exhibits bimodal or multimodal characteristics. In particular, such a bimodal or multimodal characteristic is different from a unimodal form having one peak with a wide molecular weight distribution, molecular weight distribution through gel permeation chromatography (GPC) analysis. It refers to having a structure in which two or more narrow peaks are visible or a peak can be divided into several peaks such as deconvolution. Through this, it is possible to design an optimized molecular structure through the relative position and expression level of each peak.

The high-density polyethylene according to the present invention is an ethylene homopolymer that does not contain any other copolymer.

The high-density polyethylene has a narrow molecular weight distribution (Mw / Mn) and a high weight average molecular weight (Mw) with high density through fine adjustment of the ratio of weight average molecular weight, number average molecular weight, and Z-average molecular weight. By having the ratio (Mz/Mw) of Mz (Z-average molecular weight) to Mz (molecular weight) in a low range, excellent water barrier properties of the film can be secured.

Specifically, the molecular weight distribution (Mw/Mn) of the high-density polyethylene may be 4.5 or less, for example, 2.0 to 4.5. Preferably, the molecular weight distribution (Mw/Mn) may be 4.3 or less, or 4.2 or less, or 4.0 or less, or 3.95 or less, or 3.9 or less. The molecular weight distribution (Mw/Mn) of the high-density polyethylene has a high density and a narrow molecular weight distribution in terms of improving water barrier properties during film processing. However, even when the molecular weight distribution is the same, it may have a high weight average molecular weight, so the molecular weight distribution (Mw / Mn) is 2.1 or more, or 2.2 or more, or 2.5 or more, or 2.8 or more, or 3 or more, or 3.2 or more, or 3.4 or higher, or 3.5 or higher.

For example, the molecular weight distribution (MWD, polydispersity index) is measured by using gel permeation chromatography (GPC, gel permeation chromatography, manufactured by Water) to measure the weight average molecular weight (Mw) and number average molecular weight (Mn) of polyethylene, It can be calculated by dividing the weight average molecular weight by the number average molecular weight.

Specifically, as a gel permeation chromatography (GPC) device, a Waters PL-GPC220 instrument and a Polymer Laboratories PLgel MIX-B 300 mm long column may be used. At this time, the measurement temperature is 160 ^° C, 1,2,4-trichlorobenzene (1,2,4-Trichlorobenzene) can be used as a solvent, and the flow rate can be applied at 1 mL / min. The polyethylene samples were pretreated by melting in trichlorobenzene (1,2,4-Trichlorobenzene) containing 0.0125% BHT at 160 ^° C for 10 hours using a GPC analyzer (PL-GP220), respectively, and 10 mg/10mL After preparing to a concentration, it can be supplied in an amount of 200 microliters (μL). Values of weight average molecular weight (Mw), number average molecular weight (Mn), and Z-average molecular weight (Mz) can be derived using a calibration curve formed using polystyrene standard specimens. At this time, a conversion method using a polystyrene standard specimen may be applied. For reference, the weight average molecular weights of the polystyrene standard specimens are 2000 g/mol, 10000 g/mol, 30000 g/mol, 70000 g/mol, 200000 g/mol, 700000 g/mol, 2000000 g/mol, and 4000000 g/mol. , 9 types of 10000000 g/mol can be used.

The weight average molecular weight (Mw) of the high-density polyethylene may be 60,000 g/mol to 150,000 g/mol. In particular, the high-density polyethylene may have a high weight average molecular weight in the same molecular weight distribution in terms of improving water barrier properties during film processing. Preferably, the weight average molecular weight (Mw) is greater than or equal to 60,500 g/mol, or greater than or equal to 61,000 g/mol, or greater than or equal to 61,500 g/mol, or greater than or equal to 62,000 g/mol, or greater than or equal to 62,500 g/mol, or greater than or equal to 63,000 g/mol mol or more, or 63,500 g/mol or more, or 64,000 g/mol or more, or 65,000 g/mol or more, and 145,000 g/mol or less, or 140,000 g/mol or less, or 135,000 g/mol or less, or 130,000 g/mol or less than or equal to 125,000 g/mol, or less than or equal to 120,000 g/mol, or less than or equal to 118,000 g/mol, or less than or equal to 115,000 g/mol, or less than or equal to 112,000 g/mol, or less than or equal to 110,000 g/mol, or less than or equal to 109,000 g/mol can

The number average molecular weight (Mn) of the high-density polyethylene may be 12,000 g/mol to 50,000 g/mol. In particular, the high-density polyethylene may have a high number average molecular weight in terms of improving water barrier properties during film processing. Preferably, the number average molecular weight (Mn) is 13,000 g/mol or more, or 14,000 g/mol or more, or 15,000 g/mol or more, or 16,000 g/mol or more, or 16,500 g/mol or more, or 17,000 g/mol or more. mol or more, or 17,500 g/mol or more, or 17,800 g/mol or more, or 18,000 g/mol or more, and 48,000 g/mol or less, or 45000 g/mol or less, or 44,000 g/mol or less, or 43,000 g/mol or less than or equal to 42,000 g/mol, or less than or equal to 40,000 g/mol, or less than or equal to 38,000, or less than or equal to 35,000 g/mol, or less than or equal to 34,000 g/mol, or less than or equal to 32,000 g/mol, or less than or equal to 31,000 g/mol.

In addition, the ratio (Mz/Mw) of Mw (weight average molecular weight) to Mz (Z-average molecular weight) of the high-density polyethylene may be 2.8 or less, for example, 2.0 to 2.8. Preferably, the Mz/Mw may be 2.75 or less, or 2.72 or less, or 2.7 or less, or 2.65 or less, or 2.6 or less. However, in terms of improving water barrier properties during film processing, it has a high density and a narrow molecular weight distribution, and the Mz/Mw is 2.0 or more, or 2.05 or more, or 2.1 or more, or 2.15 or more, or 2.2 or more, or 2.22 or more. , or 2.25 or greater, or 2.3 or greater.

As described above, for fine adjustment of the ratio of weight average molecular weight, number average molecular weight, and Z-average molecular weight, the Z-average molecular weight (Mz) of the high-density polyethylene may be 130,000 g / mol to 500,000 g / mol. Preferably, the Z-average molecular weight (Mz) is 140,000 g/mol or more, or 145,000 g/mol or more, or 150,000 g/mol or more, or 155,000 g/mol or more, or 160,000 g/mol or more, or 165,000 or more , or greater than or equal to 168,000 g/mol, or greater than or equal to 170,000 g/mol, or greater than or equal to 171,000 g/mol, but less than or equal to 480,000, or less than or equal to 450,000 g/mol, or less than or equal to 400,000 g/mol, or less than or equal to 350,000 g/mol, or less than or equal to 320,000 g /mol or less, or 300,000 g/mol or less, or 280,000 g/mol or less, or 260,000 g/mol or less, or 250,000 g/mol or less, or 249,000 g/mol or less, or 248,000 g/mol or less.

For example, the Z-average molecular weight (Mz) of the high-density polyethylene is measured using gel permeation chromatography (GPC, gel permeation chromatography, manufactured by Water) in the same manner as described above, and the conversion method using a polystyrene standard specimen can be obtained by applying

On the other hand, the high-density polyethylene of the present invention, as described above, has a high density while realizing an effective molecular structure through fine adjustment of the ratio of the weight average molecular weight, number average molecular weight, and Z-average molecular weight. In particular, the high-density polyethylene has a density (ASTM D1505, 23° C.) of about 0.960 g/cm ³ to 0.975 g/cm ³ , preferably about 0.961 g/cm ³ to 0.972 g/cm ³ , or about 0.962 g /cm ³ to 0.970 g/cm ³ , or about 0.963 g/cm ³ to 0.968 g/cm ³ , or about 0.964 g/cm ³ to 0.966 g/cm ³ . This means that the content of the crystal structure of polyethylene is high and dense, and accordingly, as the crystalline region in the entire film increases, the amorphous region decreases, so that water molecules can be effectively blocked, and the water barrier properties of the film can be remarkably improved.

On the other hand, the high-density polyethylene according to the present invention is characterized in that it is produced by a bimodal homopolymerization process using only two reactors (CSTR) as described above. Here, the bimodal homopolymerization process consists of polymerizing each of the above-described two reactors using different polymerization conditions and simply mixing them in a post reactor. A specific example of the bimodal homopolymerization process may refer to Examples described later.

The high-density polyethylene may be produced by a bimodal homopolymerization process in the presence of a metallocene catalyst containing only a metallocene compound represented by Formula 1 below as a catalytically active component.

[Formula 1]

(Cp ¹ R ^a ) _n (Cp ² R ^b )M ¹ Z ¹ _3-n

In Formula 1,

M ¹ is a Group 4 transition metal;

Cp ¹ and Cp ² are the same as or different from each other, and are each independently selected from the group consisting of cyclopentadienyl, indenyl, 4,5,6,7-tetrahydro-1-indenyl, and fluorenyl radicals. one, which may be substituted with a hydrocarbon having 1 to 20 carbon atoms;

R ^a and R ^b are the same as or different from each other, and are each independently hydrogen, C _1-20 alkyl, C _1-10 alkoxy, C _2-20 alkoxyalkyl, C _6-20 aryl, C _6-10 aryloxy, C _2-20 alkenyl, C _7-40 alkylaryl, C _7-40 arylalkyl, C _8-40 arylalkenyl, or C _2-10 alkynyl;

Z ¹ is a halogen atom, C _1-20 alkyl, C _2-10 alkenyl, C _7-40 alkylaryl, C _7-40 arylalkyl, C _6-20 aryl, substituted or unsubstituted C _1-20 alkylidene , substituted or unsubstituted amino, C _2-20 alkylalkoxy, or C _7-40 arylalkoxy; and

n is 1 or 0;

The substituents are described in more detail as follows.

The C _1-20 alkyl includes straight-chain or branched-chain alkyl, and specifically includes methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, pentyl, hexyl, heptyl, or octyl. However, it is not limited thereto.

The C _2-20 alkenyl includes straight-chain or branched-chain alkenyl, and specifically includes allyl, ethenyl, propenyl, butenyl, or pentenyl, but is not limited thereto.

The C _6-20 aryl includes monocyclic or condensed cyclic aryl, and specifically includes phenyl, biphenyl, naphthyl, phenanthrenyl, or fluorenyl, but is not limited thereto.

The C _5-20 heteroaryl includes monocyclic or condensed cyclic heteroaryl, and is selected from carbazolyl, pyridyl, quinoline, isoquinoline, thiophenyl, furanyl, imidazole, oxazolyl, thiazolyl, triazine, tetra Hydropyranil, tetrahydrofuranil, etc. may be mentioned, but is not limited thereto.

Examples of the C _1-20 alkoxy include methoxy, ethoxy, isopropoxy, n-butoxy, tert-butoxy, or cyclohexyloxy, but are not limited thereto.

Examples of the C _6-10 aryloxy include phenoxy, biphenoxy, or naphthoxy, but are not limited thereto.

Halogen may include fluorine (F), chlorine (Cl), bromine (Br), or iodine (I), but is not limited thereto.

Examples of the Group 4 transition metal include titanium (Ti), zirconium (Zr), or hafnium (Hf), but are not limited thereto.

The above-mentioned substituents are optionally hydroxy groups within the range of exhibiting the same or similar effects to the desired effect; halogen; alkyl or alkenyl, aryl, alkoxy; Alkyl or alkenyl, aryl, alkoxy containing at least one heteroatom among the heteroatoms of Groups 14 to 16; silyl; alkylsilyl or alkoxysilyl; phosphine group; phosphide group; sulfonate group; And it may be substituted with one or more substituents selected from the group consisting of sulfone groups.

The metallocene catalyst for performing ethylene polymerization of the present invention may use a catalyst precursor, which is a catalyst active component, containing only the metallocene compound represented by Chemical Formula 1 alone.

In particular, the metallocene compound represented by Chemical Formula 1 has good hydrogen reactivity, and when used in the form of a single supported catalyst, the molecular structure can be easily controlled according to the amount of hydrogen input. On the other hand, when it is used in the form of a hybrid supported catalyst, since two precursors are included, that is, a separate catalytically active material is additionally included in addition to the metallocene compound represented by Formula 1, the molecule is controlled by controlling process parameters. There is a limit to finely adjusting the structure, and it is not easy to grasp the trend accordingly. Therefore, in the present invention, by performing a polymerization process through a bimodal process with a single supported catalyst containing only the metallocene compound represented by Formula 1 as a catalytically active component, finely adjusting the molecular structure of high-density polyethylene to process the film It is effective in improving processability and moisture barrier properties without deteriorating mechanical properties.

Specifically, in Formula 1, M ¹ may be zirconium (Zr) or hafnium (Hf), preferably zirconium (Zr). In addition, Cp ¹ and Cp ² may each be cyclopentadienyl, indenyl, or fluorenyl. In addition, R ^a and R ^b may each be hydrogen, C _1-6 alkyl, C _7-12 arylalkyl, C _2-12 alkoxyalkyl, C _6-12 aryl, or C _2-6 alkenyl, preferably hydrogen, methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, pentyl, hexyl, butenyl, phenyl, phenyl substituted methyl, phenyl substituted butyl, or tert-butoxyhexyl. In addition, Z ¹ may each be a halogen atom, preferably chlorine (Cl). Also, n may be 1.

The compound represented by Formula 1 may be, for example, a compound represented by one of the following structural formulas, but is not limited thereto.

.

.

The method for preparing the metallocene compound was specifically described in Examples to be described later.

Meanwhile, in the present invention, the metallocene catalyst is a catalyst in which the metallocene compound represented by Chemical Formula 1 is solely supported as a catalytically active component.

The metallocene catalyst may be supported on a carrier together with a cocatalyst compound.

The metallocene catalyst can improve processability and water barrier properties without deterioration of film properties by lowering Mz/Mw with high density and narrow molecular weight distribution in the high-density polyethylene produced.

In the metallocene catalyst according to the present invention, the cocatalyst supported on the carrier to activate the metallocene compound is an organometallic compound containing a Group 13 metal, which can polymerize olefins under a general metallocene catalyst. It is not particularly limited as long as it can be used when.

Specifically, the cocatalyst may be at least one selected from the group consisting of compounds represented by Formulas 2 to 4 below:

[Formula 2]

-[Al(R ₂₁ )-O] _c -

In Formula 2,

each R ₂₁ is independently halogen, C _1-20 alkyl or C _1-20 haloalkyl;

c is an integer greater than or equal to 2;

[Formula 3]

D(R ₃₁ ) ₃

In Formula 3,

D is aluminum or boron;

each R ₃₁ is independently hydrogen, halogen, C _1-20 hydrocarbyl or halogen-substituted C _1-20 hydrocarbyl;

[Formula 4]

[LH] ⁺ [Q(E) ₄ ] ^- or [L] ⁺ [Q(E) ₄ ] ^-

In Formula 4,

L is a neutral or cationic Lewis base;

[LH] ⁺ is a Bronsted acid,

Q is B ³⁺ or Al ³⁺ ;

E is each independently C _6-20 aryl or C _1-20 alkyl, wherein the C _6-20 aryl or C _1-20 alkyl is unsubstituted or is selected from halogen, C _1-20 alkyl, C _1-20 alkoxy and It is substituted with one or more substituents selected from the group consisting of C _6-20 aryloxy.

The compound represented by Chemical Formula 2 may be, for example, an alkylaluminoxane such as modified methylaluminoxane (MMAO), methylaluminoxane (MAO), ethylaluminoxane, isobutylaluminoxane, or butylaluminoxane.

The alkyl metal compound represented by Formula 3 is, for example, trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, dimethylchloroaluminum, dimethylisobutylaluminum, dimethylethylaluminum, diethylchloro Aluminum, triisopropylaluminum, tri-s-butylaluminum, tricyclopentylaluminium, tripentylaluminium, triisopentylaluminium, trihexylaluminum, ethyldimethylaluminium, methyldiethylaluminum, triphenylaluminum, tri-p-tolyl aluminum, dimethylaluminum methoxide, dimethylaluminum ethoxide, trimethylboron, triethylboron, triisobutylboron, tripropylboron, tributylboron and the like.

The compound represented by Formula 4 is, for example, triethylammonium tetraphenylboron, tributylammonium tetraphenylboron, trimethylammonium tetraphenylboron, tripropylammonium tetraphenylboron, trimethylammonium tetra (p- Tolyl) boron, tripropylammonium tetra (p-tolyl) boron, triethylammonium tetra (o, p-dimethylphenyl) boron, trimethylammonium tetra (o, p-dimethylphenyl) boron, tributylammonium tetra (p-trifluoromethylphenyl) boron, trimethylammonium tetra(p-trifluoromethylphenyl) boron, tributylammonium tetrapentafluorophenyl boron, N,N-dimethylanilinium tetraphenyl boron, N,N -Diethylanilinium tetraphenyl boron, N,N-diethylanilinium tetrapentafluorophenyl boron, diethylammonium tetrapentafluorophenyl boron, triphenylphosphonium tetraphenyl boron, trimethylphosphonium tetraphenyl Boron, triethylammonium tetraphenyl aluminum, tributylammonium tetraphenyl aluminum, trimethylammonium tetraphenyl aluminum, tripropylammonium tetraphenyl aluminum, 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 tetrapentafluorophenyl aluminum, N,N-dimethylanilinium tetraphenyl aluminum, N,N-diethylanilinium tetraphenyl aluminum, N,N-diethylanilinium tetrapentafluorophenyl Aluminum, diethylammonium tetrapentafluorophenyl aluminum, triphenylphosphonium tetraphenyl aluminum, trimethylphosphonium tetraphenyl aluminum, triphenyl carbonium tetraphenyl boron, triphenyl carbonium tetraphenyl aluminum, triphenyl carbonone Umtetra (p-trifluoromethylphenyl) boron, triphenylcarbonium tetrapentafluorophenylboron, and the like may be used.

The supported amount of the cocatalyst may be 5 mmol to 20 mmol based on 1 g of the carrier.

In the supported metallocene catalyst according to the present invention, the weight ratio of all transition metals included in the metallocene compound represented by Chemical Formula 1 to the carrier may be 1:10 to 1:1,000. When the carrier and the metallocene compound are included in the above weight ratio, an optimal shape can be exhibited. In addition, the weight ratio of the cocatalyst compound to the carrier may be 1:1 to 1:100.

In the metallocene alone-supported catalyst according to the present invention, a carrier containing a hydroxyl group on the surface may be used as the carrier, preferably a highly reactive hydroxyl group and a siloxane group that has been dried to remove moisture from the surface. Any carrier you have can be used.

For example, silica dried at high temperature, silica-alumina, and silica-magnesia may be used, and these are typically oxides, carbonates, such as Na ₂ O, K ₂ CO ₃ , BaSO ₄ , and Mg(NO ₃ ) ₂ , It may contain sulfate and nitrate components.

The drying temperature of the carrier is preferably 200 to 800 °C, more preferably 300 to 600 °C, and most preferably 300 to 400 °C. When the drying temperature of the support is less than 200 ° C, the moisture on the surface is too high, and the moisture on the surface and the cocatalyst react, and when the drying temperature exceeds 800 ° C, the pores on the surface of the carrier are combined and the surface area is reduced. This is undesirable because only siloxane remains and the reaction site with the cocatalyst decreases.

The amount of hydroxy groups on the surface of the carrier is preferably 0.1 to 10 mmol/g, more preferably 0.5 to 5 mmol/g. The amount of hydroxyl groups on the surface of the carrier can be controlled by the manufacturing method and conditions of the carrier or drying conditions, such as temperature, time, vacuum or spray drying.

If the amount of the hydroxy group is less than 0.1 mmol / g, there are few reaction sites with the cocatalyst, and if it exceeds 10 mmol / g, it is not preferable because it may originate from moisture in addition to the hydroxy group present on the surface of the carrier particle. not.

Meanwhile, the high-density polyethylene according to the present invention can be produced by homopolymerizing ethylene in a bimodal homopolymerization process in the presence of the above-described metallocene catalyst.

The bimodal homopolymerization reaction described above may be performed by homopolymerizing ethylene using one continuous slurry polymerization reactor, a loop slurry reactor, a gas phase reactor, or a solution reactor.

Specifically, the bimodal homopolymerization process may include (a) introducing hydrogen gas in an amount of 0.006 parts by weight or more based on 100 parts by weight of ethylene in the presence of the metallocene catalyst, and performing ethylene homopolymerization to obtain a first polyethylene;

(b) in the presence of the metallocene catalyst, injecting hydrogen gas in an amount of 0.005 parts by weight or less based on 100 parts by weight of ethylene, and performing ethylene homopolymerization to obtain a second polyethylene; and

(c) mixing the first polyethylene and the second polyethylene;

Step (a) consists of obtaining first polyethylene by polymerizing ethylene while introducing hydrogen gas in the presence of a metallocene catalyst in a first reactor.

Step (a) may be performed by introducing hydrogen gas in an amount of 0.006 parts by weight or more or 0.006 to 0.015 parts by weight based on 100 parts by weight of ethylene. Preferably, the hydrogen gas may be added in an amount of 0.006 parts by weight or more, or 0.007 parts by weight or more, or 0.008 parts by weight or more, or 0.009 parts by weight or more, or 0.01 parts by weight or more. The hydrogen gas content may be in the range as described above in terms of effectively producing the first polyethylene having a low molecular weight. In addition, the hydrogen gas may be introduced in an amount of 0.015 parts by weight or less, or 0.014 parts by weight or less, or 0.013 parts by weight or less, or 0.012 parts by weight or less. The hydrogen gas content may be in the range as described above in terms of fine adjustment of process parameters for stabilization of polymerization conditions.

In step (a), the polymerization temperature is about ^25o C to about ^500o C, preferably about ^25o C to about ^200o C, or about ^30o C to about 150 ^o C, or about 40 ^{o C.} C to about 120 ^° C, or about 45 ^° C to about 100 ^° C, or about 50 ^° C to about 85 ^° C. In addition, the polymerization pressure is about 1 kgf/cm ² to about 100 kgf/cm ² , preferably about 1 kgf/cm ² to about 50 kgf/cm ² , more preferably about 5 kgf/cm ² to about 30 kgf /cm ² .

The polymerization conditions of the step (a) enable effective production of the first polyethylene having a low molecular weight in the presence of hydrogen within a predetermined range.

In step (a), the content of the metallocene catalyst is 0.002 to 0.015 parts by weight, or 0.003 to 0.014 parts by weight, or 0.004 to 0.014 parts by weight, or 0.005 parts by weight based on 100 parts by weight of ethylene. to 0.013 parts by weight, or 0.006 parts by weight to 0.012 parts by weight, or 0.007 parts by weight to 0.011 parts by weight, or 0.008 parts by weight to 0.010 parts by weight.

For example, in step (a), the metallocene catalyst is 600 mg/h to 920 mg/h, or 650 mg/h to 910 mg/h, or 680 mg/h to 900 mg/h, or 700 mg/h to 890 mg/h, or 750 mg/h to 870 mg/h, or 780 mg/h to 850 mg/h may be introduced.

In this case, the content of the metallocene compound represented by Chemical Formula 1 in the metallocene catalyst may be 0.20 wt% to 0.50 wt% based on the total weight of the catalyst.

The first polyethylene obtained through step (a) is an ethylene homopolymer.

In addition, the first polyethylene has a density of 0.960 g/cm ³ to 0.975 g/cm ³ , or 0.950 g/cm ³ to 0.970 g/cm ³ , and a weight average molecular weight (Mw) of 40,000 g/mol to 60,000 g/cm 3 . mol, or 45,000 g/mol to 55,000 g/mol, a number average molecular weight (Mn) of 10,000 g/mol to 25,000 g/mol, or 15,000 g/mol to 20,000 g/mol, and a Z-average molecular weight (Mz) 95,000 g / mol to 117,000 g / mol, or 100,000 g / mol to 110,000 g / mol, and the molecular weight distribution (Mw / Mn) may be 2.5 to 4, or 2.8 to 3.5.

Meanwhile, the high-density polyethylene according to the present invention performs step (b) separately from step (a), and step (b) uses a second reactor to produce ethylene without introducing hydrogen gas in the presence of a metallocene catalyst. Homopolymerization is performed to obtain the second polyethylene.

Unlike step (a), step (b) is performed under conditions in which hydrogen gas is minimized.

Step (b) may be performed by introducing hydrogen gas in an amount of 0.005 parts by weight or less or 0 to 0.005 parts by weight based on 100 parts by weight of ethylene. Preferably, the hydrogen gas may be introduced in an amount of 0.0045 parts by weight or less, or 0.004 parts by weight or less, or 0.0035 parts by weight or less. The hydrogen gas content may be in the range as described above in terms of effectively producing the second polyethylene having a high molecular weight. In addition, the hydrogen gas may be introduced in an amount of 0.001 parts by weight or more, or 0.0015 parts by weight or more, or 0.002 parts by weight or more, or 0.0025 parts by weight or more. The hydrogen gas content may be in the range as described above in terms of fine adjustment of process parameters for stabilization of polymerization conditions.

And, in step (b), the polymerization temperature is about ^25o C to about ^500o C, preferably about ^25o C to about ^200o C, or about ^30o C to about 150 ^o C, or about 40 ^{o C.} C to about 120 ^° C, or about 45 ^° C to about 100 ^° C, or about 50 ^° C to about 85 ^° C. In addition, the polymerization pressure is about 1 kgf/cm ² to about 100 kgf/cm ² , preferably about 1 kgf/cm ² to about 50 kgf/cm ² , more preferably about 5 kgf/cm ² to about 30 kgf /cm ² .

The polymerization conditions in the step (b) enable effective production of the second polyethylene having a high molecular weight under conditions in which there is no or a small amount of hydrogen gas.

In the step (b), the content of the metallocene catalyst is 0.002 to 0.015 parts by weight, or 0.003 to 0.014 parts by weight, or 0.004 to 0.014 parts by weight, or 0.005 parts by weight based on 100 parts by weight of ethylene. to 0.013 parts by weight, or 0.006 parts by weight to 0.012 parts by weight, or 0.007 parts by weight to 0.011 parts by weight, or 0.008 parts by weight to 0.010 parts by weight.

For example, in step (b), the metallocene catalyst is 600 mg/h to 920 mg/h, or 650 mg/h to 910 mg/h, or 680 mg/h to 900 mg/h, or 700 mg/h to 890 mg/h, or 750 mg/h to 870 mg/h, or 780 mg/h to 850 mg/h may be introduced.

In this case, the content of the metallocene compound represented by Chemical Formula 1 in the metallocene catalyst may be 0.20 wt% to 0.50 wt% based on the total weight of the catalyst.

The second polyethylene obtained through step (b) is an ethylene homopolymer.

In addition, the second polyethylene has a density of 0.960 g/cm ³ to 0.975 g/cm ³ , or 0.950 g/cm ³ to 0.970 g/cm ³ , and a weight average molecular weight (Mw) of 100,000 g/mol to 150,000 g/cm 3 . mol, or 110,000 g/mol to 140,000 g/mol, a number average molecular weight (Mn) of 30,000 g/mol to 50,000 g/mol, or 35,000 g/mol to 45,000 g/mol, and a Z-average molecular weight (Mz) 240,000 g/mol to 270,000 g/mol, or 250,000 g/mol to 265,000 g/mol, and the molecular weight distribution (Mw/Mn) may be 2.5 to 3.5 or 2.8 to 3.2.

On the other hand, the high-density polyethylene according to the present invention is prepared by including the step (c) of mixing the first polyethylene obtained through step (a) and the second polyethylene obtained through step (b) using a third reactor. may have been

In step (c), the weight ratio of the first polyethylene and the second polyethylene is 15:85 to 85:15, or 17:83 to 83:17, or 25:75 to 75:25, or 30: It is carried out while mixing in a weight ratio of 70 to 70:30. The mixing ratio of the first polyethylene and the second polyethylene may be in the range as described above in terms of optimizing the melt index and density of the composition.

The step (c) is performed under conditions in which there is no hydrogen gas, and is performed without additionally introducing a C _4-12 alpha-olefin or the like.

However, in step (c), a small amount of ethylene may be added to stabilize the post-reaction. In this case, in step (c), ethylene is 10 kg/h or less, or 0.1 to 10 kg/h, or 10 kg/h. h or less or 0.1 to 5 kg/h, 10 kg/h or less or 0.1 to 3.5 kg/h.

In addition, since the step (c) is not a separate polymerization process as described above, but a process aimed at simply blending, the polymerization temperature and pressure do not necessarily need to be maintained high, but within an appropriate range for process efficiency. can be done Specifically, the reactor temperature in step (c) is about ^25o C to about ^500o C, preferably about ^25o C to about ^200o C, or about ^30o C to about ^150o C, or about 40o ^C. C to about 120 ^° C, or about 45 ^° C to about 100 ^° C, or about 50 ^° C to about 85 ^° C. In addition, the reactor pressure is about 1 kgf/cm ² to about 100 kgf/cm ² , preferably about 1 kgf/cm ² to about 50 kgf/cm ² or about 1 kgf/cm ² to about 15 kgf/cm ² , or about 1 kgf/cm ² to about 10 kgf/cm ² or about 1 kgf/cm ² to about 5 kgf/cm ² .

As an example, the high-density polyethylene according to the present invention, as shown in Figure 1, the first polymerization reactor (R1) for producing the first polyethylene through step (a), and the second polyethylene through step (b) A second polymerization reactor (R2) for preparing, and a reactor (Post-R, for mixing the first polyethylene and the second polyethylene obtained in the first polymerization reactor (R1) and the second polymerization reactor (R2) through step (c) It may be manufactured using a device composed of a post reactor).

The above-described high-density polyethylene maintains a low extrusion load without deterioration of mechanical properties during film processing, and has excellent processability and high Moisture barrier can be secured. Accordingly, such high-density polyethylene is useful for manufacturing a film requiring high moisture barrier properties, in particular, a food packaging film.

Accordingly, according to another embodiment of the present invention, a film comprising the high-density polyethylene of the above-described embodiment, for example, a film requiring high moisture barrier properties, particularly a food packaging film, is provided.

As the film includes the above-described high-density polyethylene, through fine adjustment of the ratio of weight average molecular weight, number average molecular weight, and Z-average molecular weight with high density, significantly improved processability and moisture barrier without deterioration of film properties gender can be indicated.

On the other hand, the polyethylene film according to the present invention, under the condition of a film thickness of 25 μm, the moisture barrier property (WVTR) on a per-day basis is 5500 mg/m ² •day or less or 500 mg/m ² •day to 5500 mg/m ² ㆍday, or 5000 mg/m ² ㆍday or less or 800 mg/m ² ㆍday to 5000 mg/m ² ㆍday, or 4500 mg/m ² ㆍday or less or 1000 mg/m ² ㆍday to 4500 mg /m ² ㆍday, or less than 4000 mg/m ² ㆍday or less than 1200 mg/m ² ㆍday to 4000 mg/m 2 ㆍday, or less than 3800 mg/m ^{2 ㆍ} day or less than 1300 mg/m ² ㆍday It may be 3800 mg/m ² ㆍday. Here, the smaller the water barrier property (WVTR) value of the film means that the water barrier property is improved.

Specifically, after processing each resin specimen into a film having a thickness of 25 μm by this film processing method, the moisture barrier performance (WVTR, water vapor transmission rate, mg/m ² ㆍday) of the film was measured by the following method can do. For example, the moisture barrier performance (WVTR) of the film is the amount of water vapor (g) permeated per 50 cm ² of the film on a daily basis at a film thickness of 25 μm, Modern Controls Inc. (Modern Controls) according to ASTM F 1249-90 Inc.) can be measured under the following conditions using Mocon AquaTran.

Film thickness: 25 μm

Film width: 50 cm ²

Humidity: 100%

Pressure: 1 bar

Temperature: 37.8 °C.

The film may be manufactured according to a general film forming method, except that the above-described high-density polyethylene is applied. Additional detailed descriptions thereof will be omitted.

As an example, the polyethylene film according to the present invention can be produced using a film forming extruder with a polyethylene composition obtained by melt-extruding high-density polyethylene as described above. For example, the high-density polyethylene is put into a single screw extruder (L / D = 20) having a diameter of 35 mm, melt-kneaded and reactively extruded at a temperature of about 240 ° C., and then cooled to obtain each pellet composition. Furthermore, a film having a thickness of 20 μm to 30 μm (average thickness 25 μm) is prepared using a film forming extruder set at a temperature of about 180° C. for the pellet composition thus obtained. At this time, as specific processing conditions, the FLH (Frost Line Height) may be 300 mm or less, and the BUR 2.5 standard extrusion amount may be maintained at 300 g/min or more.

Hereinafter, a preferred embodiment is presented to aid understanding of the present invention. However, the following examples are only provided to more easily understand the present invention, and the content of the present invention is not limited thereby.

<Preparation of Catalyst Precursor>

Synthesis Example 1

Using 6-chlorohexanol, t-butyl-O-(CH ₂ ) ₆ -Cl was prepared by the method described in the literature (Tetrahedron Lett. 2951 (1988)), and cyclopentathidenyl sodium (NaCp) was added thereto. The reaction gave t-butyl-O-(CH ₂ ) ₆ -C ₅ H ₅ (yield 60%, bp 80 ^o C/0.1 mmHg).

In addition, after dissolving t-butyl-O-(CH ₂ ) ₆ -C ₅ H ₅ in tetrahydrofuran (THF) at -78 ^o C and slowly adding n-butyllithium (n-BuLi), the temperature was raised to room temperature. After that, it was reacted for 8 hours. The lithium salt solution synthesized above was slowly added to the suspension solution of ZrCl ₄ (THF) ₂ (170 g, 4.50 mmol)/THF (30 mL) at -78 ^o C and further reacted at room temperature for 6 hours. made it All volatile substances were removed by vacuum drying, and hexane was added to the obtained oily liquid substance for filtering. After vacuum drying the filter solution, hexane was added to induce a precipitate at low temperature (-20 ^° C). The obtained precipitate was filtered at low temperature to obtain [tert-butyl-O-(CH ₂ ) ₆ -C ₅ H ₄ ] ₂ ZrCl ₂ ] in the form of a white solid (yield: 92%).

¹ H-NMR (300 MHz, CDCl ₃ ): 6.28 (t, J=2.6 Hz, 2H), 6.19 (t, J=2.6 Hz, 2H), 3.31 (t, 6.6 Hz, 2H), 2.62 (t, J=8 Hz), 1.7 - 1.3 (m, 8H), 1.17 (s, 9H)

¹³ C-NMR (CDCl ₃ ): 135.09, 116.66, 112.28, 72.42, 61.52, 30.66, 30.31, 30.14, 29.18, 27.58, 26.00

Synthesis Example 2

From the reaction between the tert-butyl-O-(CH ₂ ) ₆ Cl compound and Mg(0) in a THF solvent, 1.0 mole of a Grignard reagent tert-butyl-O-(CH ₂ ) ₆ MgCl solution was obtained. The prepared Grignard compound was added to a flask containing (CH ₃ )SiCl ₃ compound (176.1 mL, 1.5 mol) and THF (2.0 mL) at -30 ° C, stirred at room temperature for 8 hours or more, and then filtered. The resulting solution was vacuum-dried to obtain a compound of tert-butyl-O-(CH ₂ ) ₆ Si(CH ₃ )Cl ₂ (yield: 92%).

At -20 ° C, fluorene (Flu, fluoren, 3.33 g, 20 mmol), hexane (100 mL) and MTBE (methyl tert-butyl ether, 1.2 mL, 10 mmol) were added to the reactor, and 8 mL of n-BuLi (2.5 M in Hexane) was slowly added, and the mixture was stirred at room temperature for 6 hours. After stirring was completed, the reactor temperature was cooled to -30 °C, and tert-butyl-O-(CH ₂ ) ₆ Si(CH ₃ )Cl ₂ (2.7 g, 10 mmol) was slowly added over 1 hour to the fluorenyl lithium solution prepared above. After stirring at room temperature for 8 hours or more, water was added to extract, and dried (evaporation) to obtain a (tert-butyl-O-(CH ₂ ) ₆ )(CH ₃ )Si(9-C ₁₃ H ₁₀ ) ₂ compound. (5.3 g, yield 100%). The structure of the ligand was confirmed through ¹ H-NMR.

¹ H NMR (500 MHz, CDCl ₃ ): -0.35 (CH ₃ Si, 3H, s), 0.26 (Si-CH ₂ , 2H, m), 0.58 (CH ₂ , 2H, m), 0.95 (CH ₂ , 4H, m), 1.17 (tert-butyl-O, 9H, s), 1.29 (CH ₂ , 2H, m), 3.21 (tert-butyl-O-CH ₂ , 2H, t), 4.10 (Flu-9H, 2H, s), 7.25 (Flu-H, 4H, m), 7.35 (Flu-H, 4H, m), 7.40 (Flu-H, 4H, m), 7.85 (Flu-H, 4H, d).

4.8 mL of n-BuLi in (tert-butyl-O-(CH ₂ ) ₆ )(CH ₃ )Si(9-C ₁₃ H ₁₀ ) ₂ (3.18 g, 6 mmol)/MTBE (20 mL) solution at -20 °C. (2.5M in Hexane) was slowly added and reacted for more than 8 hours while raising the temperature to room temperature, and then the prepared dilithium salts slurry solution was prepared above at -20 ° C. ZrCl ₄ (THF) ₂ (2.26 g, 6mmol) / Hexane (20 mL) was slowly added as a slurry solution and further reacted at room temperature for 8 hours. The precipitate was filtered and washed with hexane several times to obtain (tert-butyl-O-(CH ₂ ) ₆ ) (CH ₃ )Si(9-C ₁₃ H ₉ ) ₂ ZrCl ₂ compound as a red solid (4.3 g , yield 94.5%).

¹ H NMR (500 MHz, C ₆ D ₆ ): 1.15 (tert-butyl-O, 9H, s), 1.26 (CH ₃ Si, 3H, s), 1.58 (Si-CH 2 , 2H, m), 1.66 ( CH2, 4H, m), 1.91 (CH2, 4H, m), 3.32 (tert-butyl-O-CH2, 2H, t), 6.86 (Flu-H, 2H, t), 6.90 (Flu-H, 2H, t), 7.15 (Flu-H, 4H, m), 7.60 (Flu-H, 4H, dd), 7.64 (Flu-H, 2H, d), 7.77 (Flu-H, 2H, d).

<Preparation of Supported Catalyst>

Preparation Example 1: Preparation of single supported catalyst

Put 10 g of dried silica into a glass reactor, add 100 mL of toluene, and stir. After adding 50 mL of a 10 wt% methylaluminoxane (MAO)/toluene solution, the mixture was reacted slowly at 40° C. while stirring. Thereafter, unreacted aluminum compounds were removed by washing with a sufficient amount of toluene, and remaining toluene was removed by reducing the pressure. After adding 100 mL of toluene again, 0.25 mmol of the metallocene compound prepared in Synthesis Example 1 was dissolved in toluene and added together to react for 1 hour. After the reaction was completed, toluene was removed under reduced pressure at 50 °C to prepare a supported catalyst.

Comparative Preparation Example 1: Preparation of Hybrid Supported Catalyst

5.0 kg of toluene solution was put into a 20 L stainless steel (sus) high-pressure reactor and the temperature of the reactor was maintained at 40 ^° C. 1000 g of silica (manufactured by Grace Davison, SP948) dehydrated by applying vacuum at a temperature of 600 ^o C for 12 hours was introduced into the reactor, and after sufficiently dispersing the silica, 84 g of the metallocene compound of Synthesis Example 1 was added to toluene. After melting, the mixture was reacted by stirring at 40 ^° C. at 200 rpm for 2 hours. After stopping the stirring and settling for 30 minutes, the reaction solution was decanted.

2.5 kg of toluene was added to the reactor, and 9.4 kg of a 10 wt% methylaluminoxane (MAO)/toluene solution was added, followed by stirring at 40 ^° C. and 200 rpm for 12 hours. After the reaction, stirring was stopped, settling was performed for 30 minutes, and the reaction solution was decanted. After adding 3.0 kg of toluene and stirring for 10 minutes, stopping stirring and settling for 30 minutes, the toluene solution was decanted.

3.0 kg of toluene was added to the reactor, and 116 g of the metallocene compound of Synthesis Example 2 was dissolved in 1 L of a toluene solution, introduced into the reactor, and reacted by stirring at 40 ^° C. at 200 rpm for 2 hours. At this time, the ratio of the metallocene compound of Synthesis Example 1 and the metallocene compound of Synthesis Example 2 was 1:1.2 based on the molar ratio. After the reactor temperature was lowered to room temperature, stirring was stopped, settling was performed for 30 minutes, and the reaction solution was decanted.

After adding 2.0 kg of toluene to the reactor and stirring for 10 minutes, stirring was stopped, settling was performed for 30 minutes, and the reaction solution was decanted.

3.0 kg of hexane was added to the reactor, the hexane slurry was transferred to a filter dryer, and the hexane solution was filtered. A 1 kg-SiO ₂ hybrid supported catalyst was prepared by drying under reduced pressure at 40 ^° C. for 4 hours.

<Preparation of ethylene homopolymer>

Example 1

Steps (a), (b), and (c) were performed in a reaction apparatus including two CSTR reactors in the following manner using the single supported catalyst prepared in Preparation Example 1 under the conditions shown in Table 1 below. This was done to produce bimodal high density polyethylene.

Specifically, as shown in FIG. 1, a device including a first polymerization reactor (R1, CSTR reactor), a second polymerization reactor (R2, CSTR reactor), and a post-treatment reactor (Post-R, post-reactor) A multimodal polyethylene composition was prepared using. First, 800 mg/h of the single supported catalyst (cat) prepared in Preparation Example 1, 10 kg/h of ethylene (C2), and 1.00 g/h of hydrogen (H ₂ ) were added to the reactor (R1) in step (a). did 800 mg/h of the single supported catalyst (cat) prepared in Preparation Example 1, 10 kg/h of ethylene (C2), and 0.30 g/h of hydrogen (H ₂ ) were added to the reactor (R2) in step (b). . There is an agitator in each reactor (R1, R2), and the rotation speed was performed at 250 to 260 rpm. In addition, triethyl aluminum (Teal) was added at 150 mL/h to remove moisture, and an antistatic agent (ASA, Atmer163) was added at 25 mL/h to prevent static electricity from occurring in the polymerized powder. In addition, hydrogen, ethylene, and 1-butene were dissolved in gaseous form, and the catalyst, Teal, and ASA were dissolved in hexane (Hx) and introduced into the reactor. Thereafter, the powders polymerized in R1 and R2 are transferred in parallel to the post-treatment reactor (Post-R) in step (c) and mixed, and at this time, the ethylene (C2) input amount was 2.7 kg / h. It was carried out under the condition.

At this time, in step (c), the mixing ratio of the first polyethylene (R1 HDPE) and the second polyethylene (R2 HDPE) was 5:25 (R1:R2) by weight.

In addition, the Mn of the first polyethylene (R1 HDPE) is 17000 g / mol, Mw is 50000 g / mol, Mz is 107000 g / mol, PDI (Mw / Mn) is 3, the second polyethylene (R2 HDPE) Mn was 39000 g/mol, Mw was 120000 g/mol, Mz was 258000 g/mol, and PDI (Mw/Mn) was 3.1. Measured as described.

unit (a) step process conditions
(R1) (b) step process conditions
(R2) (c) step process conditions
(Post-R) Catalyst input mg/h 800 800 - Ethylene input kg/h 10 10 2.7 _H2 input g/h 1.00 0.30 0 1-butene dosage g/h 0 0 0 enter bar 7.9 8.0 2.1 reactor temperature ^o C 83.5 81.8 80 activation kg PE/ g·cat·hr 23.7 4.8 -

In Table 1, the catalyst activity (activity, kg PE / g cat hr) is the first polyethylene (R1-HDPE) and the second polyethylene (R1-HDPE) produced per supported catalyst mass (g) used based on unit time (h). Each was calculated as a ratio of the weight (kg PE) of polyethylene (R2-HDPE).

In addition, as shown in Table 1, the post-treatment reactor (Post-R) performing the step of mixing the first polyethylene and the second polyethylene in the embodiment is not for performing an additional polymerization process, The main purpose is to simply blend the high-density polyethylene (HDPE) powder obtained in the first polymerization reactor (R1) and the second polymerization reactor (R2). Therefore, the post-treatment reactor (Post-R) can be operated to such an extent that only a blending process is performed without inputting 1-butene or hydrogen, while introducing a small amount of ethylene only when necessary for post-process stabilization. In this post-treatment reactor (Post-R), the reactor temperature and pressure can be relatively low at 80 °C and 2.1 bar, respectively.

Example 2

It was prepared in the same manner as in Example 1, but in step (c), the mixing ratio of the first polyethylene (R1 HDPE) and the second polyethylene (R2 HDPE) was changed to 10:20 (R1:R2) by weight, 1, to prepare bimodal high-density polyethylene.

Example 3

It was prepared in the same manner as in Example 1, but in step (c), the mixing ratio of the first polyethylene (R1 HDPE) and the second polyethylene (R2 HDPE) was changed to 15:15 (R1:R2) by weight, 1, to prepare bimodal high-density polyethylene.

Example 4

It was prepared in the same manner as in Example 1, but in step (c), the mixing ratio of the first polyethylene (R1 HDPE) and the second polyethylene (R2 HDPE) was changed to 20:10 (R1:R2) by weight, It was carried out under the conditions shown in Table 1 to prepare bimodal high-density polyethylene.

Example 5

It was prepared in the same manner as in Example 1, but in step (c), the mixing ratio of the first polyethylene (R1 HDPE) and the second polyethylene (R2 HDPE) was changed to 25:5 (R1:R2) by weight, It was carried out under the conditions shown in Table 1 to prepare bimodal high-density polyethylene.

Comparative Example 1

It was prepared in the same manner as in Example 1, but using the hybrid supported catalyst prepared in Preparation Example 2, the catalyst input amount, ethylene input amount, and hydrogen input amount in steps (a) and (b) under the conditions shown in Table 2 below were mutually The same was done to prepare high-density polyethylene.

unit (a) step process conditions
(R1) (b) step process conditions
(R2) (c) step process conditions
(Post-R) Catalyst input mg/h 900 900 - Ethylene input kg/h 10 10 2.7 _H2 input g/h 3.35 3.35 0 1-butene dosage g/h 0 0 0 enter bar 7.96 7.96 2.1 reactor temperature ^o C 82.3 82.3 80 activation kg PE/ g·cat·hr 10.2 10.2 -

Comparative Examples 2 to 5 It was prepared in the same manner as in Comparative Example 1, but the catalyst input amount, ethylene input amount, and hydrogen input amount were varied in steps (a) and (b) under the conditions shown in Table 3 below, and steps (a) and ( By performing the same process conditions of step b), high-density polyethylene was prepared.

unit (a), (b) process conditions (R1, R2) Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Catalyst input mg/h 900 900 900 900 Ethylene input kg/h 10 10 10 10 _H2 input g/h 3.2 3.1 2.35 2.35 1-butene dosage g/h 0 0 0 0 enter bar 7.15 7.8 7.9 7.8 reactor temperature ^o C 82.1 82.7 82.6 82.3 activation kg PE/ g·cat·hr 10.7 10.9 11.8 11.4

<Evaluation of physical properties of high-density polyethylene and film> Test Example 1

The physical properties of the high-density polyethylene prepared in Examples and Comparative Examples were measured in the following manner, and the results are shown in Table 1 below.

(1) Density

Density (g/cm ³ ) of high-density polyethylene was measured according to ASTM D 1505.

(2) Weight average molecular weight (Mw) and molecular weight distribution (PDI, polydispersity index)

Mw (weight average molecular weight), Mz (Z-average molecular weight) and Mn (number average molecular weight) of polyethylene were measured using gel permeation chromatography (GPC, gel permeation chromatography, manufactured by Water), and the weight average molecular weight was measured. Mw/Mn (PDI, molecular weight distribution) and Mz/Mw were calculated by dividing by the average molecular weight.

Specifically, a Waters PL-GPC220 instrument was used as a gel permeation chromatography (GPC) apparatus, and a Polymer Laboratories PLgel MIX-B 300 mm long column was used. At this time, the measurement temperature was 160 ^° C, 1,2,4-trichlorobenzene was used as a solvent, and the flow rate was 1 mL/min. Polyethylene samples according to Examples and Comparative Examples each contained 0.0125% of dibutylhydroxytoluene (BHT, 2,6-bis(1,1-dimethylethyl)-4-methylphenol) using a GPC analyzer (PL-GP220). It was pretreated by dissolving in 1,2,4-Trichlorobenzene at 160 ^o C for 10 hours, prepared at a concentration of 10 mg/10mL, and then supplied in an amount of 200 μL. The values of Mw and Mn were derived using a calibration curve formed using polystyrene standard specimens. The weight average molecular weight of the polystyrene standard specimen is 2000 g/mol, 10000 g/mol, 30000 g/mol, 70000 g/mol, 200000 g/mol, 700000 g/mol, 2000000 g/mol, 4000000 g/mol, 10000000 g / mol of 9 species were used.

Example comparative example One 2 3 4 5 One 2 3 4 5 catalyst Preparation Example 1 Preparation Example 1 Preparation Example 1 Preparation Example 1 Preparation Example 1 Comparative Manufacturing Example 1 Comparative Manufacturing Example 1 Comparative Manufacturing Example 1 Comparative Manufacturing Example 1 Comparative Manufacturing Example 1 Support form stand alone stand alone stand alone stand alone stand alone mixed support mixed support mixed support mixed support mixed support active ingredient Synthesis Example 1 Synthesis Example 1 Synthesis Example 1 Synthesis Example 1 Synthesis Example 1 Synthesis Example 1/Synthesis Example 2 Synthesis Example 1/Synthesis Example 2 Synthesis Example 1/Synthesis Example 2 Synthesis Example 1/Synthesis Example 2 Synthesis Example 1/Synthesis Example 2 Density (g/cm ³ ) 0.965 0.964 0.964 0.965 0.964 0.966 0.965 0.964 0.964 0.964 Mn (X10 ³ g/mol) 31 26 23 21 18 10 9 11 13 10 Mw (X10 ³ g/mol) 109 98 90 78 65 119 115 120 123 111 Mz (X10 ³ g/mol) 248 230 228 206 171 599 592 572 564 539 Mz/Mw 2.3 2.3 2.5 2.6 2.6 5 5.1 4.8 4.6 4.9 Mw/Mn 3.5 3.8 3.9 3.8 3.6 12 12.7 10.5 9.9 10.6

As shown in Table 4, it can be seen that the high-density polyethylene of Examples 1 to 5 of the present invention has a high density and low Mw/Mn and Mz/Mw compared to Comparative Examples 1 to 5.

Test Example 2

The physical properties of the films prepared using the high-density polyethylene according to Examples and Comparative Examples were measured in the following manner, and the results are shown in Table 5 below.

Specifically, each of the high-density polyethylenes of Examples and Comparative Examples was put into a single screw extruder (L/D = 20) having a diameter of 35 mm, melt-kneaded and reactive-extruded at a temperature of about 240 ° C., and then cooled to each pellet composition. was obtained. Further, each pellet composition obtained in this way was prepared into a film having a thickness of 20 μm to 30 μm (average thickness 25 μm) using a film forming extruder set at a temperature of about 180 ° C. At this time, as specific processing conditions, the FLH (Frost Line Height) was set to 300 mm or less, and the BUR 2.5 standard extrusion amount was maintained at 300 g/min or more. After each resin specimen was processed into a film having a thickness of 25 μm by this film processing method, the moisture barrier performance (WVTR, water vapor transmission rate, mg/m ² ·day) of the film was measured in the following manner.

(1) Film moisture barrier (WVTR)

WVTR is the amount of water vapor (g) transmitted per film 50 cm ² per day at a film thickness of 25 μm, using Mocon AquaTran from Modern Controls Inc. according to ASTM F 1249-90 as follows: Measurements were made under the same conditions. A smaller WVTR value means improved moisture barrier properties.

Film thickness: 25 μm

Film width: 50 cm ²

Humidity: 100%

Pressure: 1 bar

Temperature: 37.8 °C.

Example comparative example One 2 3 4 5 One 2 3 4 5 WVTR
(mg/ ^m2 Day) 3308.4 3403.9 3500.6 3575.1 3678.4 4836.9 4633.9 5406.9 5684.8 5326.7

As shown in Table 5, the high density of Examples 1 to 5, in which the molecular structure was optimized through fine adjustment of the ratio of weight average molecular weight, number average molecular weight, and Z-average molecular weight, along with high density according to the present invention It can be seen that the polyethylene film is remarkably superior in moisture barrier properties compared to Comparative Examples 1 to 5.

Claims (12)

The molecular weight distribution (Mw/Mn) is 4.5 or less,
The ratio (Mz/Mw) of Mz (Z-average molecular weight) to Mw (weight average molecular weight) is 2.8 or less,
having a density of 0.960 g/cm 3 to 0.975 g/cm 3 measured according to ASTM D 1505;
high-density polyethylene.
According to claim 1,
The polyethylene is an ethylene homopolymer,
high-density polyethylene.
According to claim 1,
having a molecular weight distribution (Mw/Mn) of 2.0 to 4.5;
high-density polyethylene.
According to claim 1,
Mw (weight average molecular weight) is 60,000 g / mol to 150,000 g / mol,
high-density polyethylene.
According to claim 1,
The ratio of Mz (Z-average molecular weight) to Mw (weight average molecular weight) (Mz/Mw) is 2.0 to 2.8,
high-density polyethylene.
According to claim 1,
Mz (Z-average molecular weight) is between 130,000 g/mol and 500,000 g/mol;
high-density polyethylene.
According to claim 1,
The polyethylene is produced by a bimodal homopolymerization process in the presence of a metallocene catalyst containing only a metallocene compound represented by Formula 1 as a catalytically active component,
High Density Polyethylene:
[Formula 1]
(Cp ¹ R ^a ) _n (Cp ² R ^b )M ¹ Z ¹ _3-n
In Formula 1,
M ¹ is a Group 4 transition metal;
Cp ¹ and Cp ² are the same as or different from each other, and are each independently selected from the group consisting of cyclopentadienyl, indenyl, 4,5,6,7-tetrahydro-1-indenyl, and fluorenyl radicals. one, which may be substituted with a hydrocarbon having 1 to 20 carbon atoms;
R ^a and R ^b are the same as or different from each other, and are each independently hydrogen, C _1-20 alkyl, C _1-10 alkoxy, C _2-20 alkoxyalkyl, C _6-20 aryl, C _6-10 aryloxy, C _2-20 alkenyl, C _7-40 alkylaryl, C _7-40 arylalkyl, C _8-40 arylalkenyl, or C _2-10 alkynyl;
Z ¹ is a halogen atom, C _1-20 alkyl, C _2-10 alkenyl, C _7-40 alkylaryl, C _7-40 arylalkyl, C _6-20 aryl, substituted or unsubstituted C _1-20 alkylidene , substituted or unsubstituted amino, C _2-20 alkylalkoxy, or C _7-40 arylalkoxy; and
n is 1 or 0;
According to claim 7,
The bimodal homopolymerization process,
(a) in the presence of the metallocene catalyst, hydrogen gas is introduced in an amount of 0.006 parts by weight or more based on 100 parts by weight of ethylene to homopolymerize ethylene to obtain a first polyethylene;
(b) in the presence of the metallocene catalyst, injecting hydrogen gas in an amount of 0.005 parts by weight or less based on 100 parts by weight of ethylene, and performing ethylene homopolymerization to obtain a second polyethylene; and
(c) mixing the first polyethylene and the second polyethylene; consisting of,
high-density polyethylene.
According to claim 8,
In step (a) and step (b), the metallocene catalysts are each independently added in an amount of 0.002 parts by weight to 0.015 parts by weight based on 100 parts by weight of ethylene.
high-density polyethylene.
According to claim 7,
In Formula 1, M ¹ is zirconium or hafnium; R ^a and R ^b are each hydrogen, C _1-6 alkyl, C _7-12 arylalkyl, C _2-12 alkoxyalkyl, C _6-12 aryl, or C _2-6 alkenyl; Z ¹ is a halogen atom,
high-density polyethylene.
According to claim 7,
The metallocene compound is a compound represented by any one of the following structural formulas,
High Density Polyethylene:

.
It contains the high-density polyethylene according to any one of claims 1 to 11, and has a water barrier property (WVTR) of 5500 mg/m ² ·day or less based on a film thickness of 25 ㎛,
polyethylene film.

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