KR102627357B1 - Polyethylene composition and method for preparing the same - Google Patents

Abstract

The present invention provides a polyethylene composition and method for producing the same, which can produce molded articles that can secure excellent environmental stress crack resistance and improve total volatile organic compound (TVOC) properties that can be generated by low molecular weight polymers. provides.

Description

Polyethylene composition and method for producing the same {POLYETHYLENE COMPOSITION AND METHOD FOR PREPARING THE SAME}

The present invention provides a polyethylene composition that can produce molded articles that can secure excellent environmental stress crack resistance and improve total volatile organic compound (TVOC) properties that can be generated by low molecular weight polymers, and a method for producing the same. It's about.

The demand for polyethylene resin is increasing and it is used in a variety of applications. As high-performance polyethylene is required for relatively new plastics, polymerization process technologies have been developed to support the production of new polymer materials.

In general, olefin polymerization catalyst systems can be classified into Ziegler-Natta and metallocene catalyst systems, and these two highly active catalyst systems have been developed to suit their respective characteristics. The Ziegler-Natta catalyst has been widely applied to existing commercial processes since its invention in the 1950s. However, because it is a multi-site catalyst with multiple active sites, it is characterized by a wide molecular weight distribution of the polymer and comonomer. There is a problem that there is a limit to securing the desired physical properties because the composition distribution is not uniform.

Meanwhile, a metallocene catalyst is composed of a combination of a main catalyst whose main component is a transition metal compound and a cocatalyst which is an organometallic compound whose main component is aluminum. Such a catalyst is a homogeneous complex catalyst and is a single site catalyst. A polymer with a narrow molecular weight distribution due to the single active site characteristics and a uniform composition distribution of the comonomer is obtained. Depending on the modification of the ligand structure of the catalyst and the change of polymerization conditions, the stereoregularity of the polymer, copolymerization characteristics, molecular weight, It has properties that can change crystallinity, etc.

U.S. Patent No. 5,914,289 describes a method of controlling the molecular weight and molecular weight distribution of a polymer using a metallocene catalyst supported on each carrier, but the amount of solvent used and the manufacturing time are large when producing the supported catalyst. , there was the inconvenience of having to support each metallocene catalyst used on a carrier.

Korean Patent Application No. 2003-12308 discloses a method of controlling molecular weight distribution by supporting a dinuclear metallocene catalyst and a mononuclear metallocene catalyst with an activator on a carrier and polymerizing them while changing the combination of catalysts in the reactor. there is. However, this method has limitations in realizing the characteristics of each catalyst simultaneously, and also has the disadvantage of causing fouling in the reactor because the metallocene catalyst portion is released from the carrier component of the completed catalyst.

In particular, when using the existing Ziegler-Natta catalyst, there is a problem in that the final molded product (bottle cap or blow molding container, etc.) contains a low molecular weight lubricant, which changes the taste of the beverage and, in severe cases, causes a bad odor. In addition, if low molecular weight total volatile organic compounds (TVOC) are generated during the injection processing process (200 °C) for producing the final molded product, harmful gases such as harmful fumes may be generated.

In particular, when polyethylene is used in the manufacture of general food and drug storage containers or closures, closures of airtight containers containing carbonated beverages (e.g. bottle caps) must be strong enough to withstand the pressure of carbonated beverages and provide an excellent seal. It must be flexible enough to provide flexibility. Specifically, rigidity to withstand the internal pressure caused by carbonated beverages in a sealed container, impact resistance at low temperatures, and environmental stress cracking resistance are required. However, polyethylene products that are currently widely sold and used have the problem that low molecular substances contained in the resin composition transfer to food when used at high temperatures, and when stored at low temperatures, polyethylene becomes hard, resulting in poor opening and closing properties, and changes in physical properties due to long-term storage. It has the problem of being easily damaged by impact.

Accordingly, when manufacturing injection molded products such as food and drug storage containers or stoppers, the problem of deterioration of sealing performance due to deterioration of physical properties during long-term storage is solved, and the total volatile organic compounds (TVOC) that can be generated by polymers in the low molecular weight region are eliminated. There is a continued need to develop polyethylene compositions that can reduce the generation of harmful gases such as ) and fume.

The present invention provides a polyethylene composition that can produce molded articles that can secure excellent environmental stress crack resistance and improve total volatile organic compound (TVOC) properties that can be generated by low molecular weight polymers, and a method of manufacturing the same. We would like to provide.

Additionally, the present invention seeks to provide an injection molded article containing the above-described polyethylene composition.

According to one embodiment of the invention, a polyethylene composition is provided, wherein the linear structure fraction ratio (R _OL ) according to the following formula 1 is 10% or less and the molecular weight distribution (Mw/Mn) is 12 or less:

[Equation 1]

R _OL = (A ₁ /A ₂ ) × 100

In equation 1 above,

R _OL represents the linear structure fraction ratio (%) contained in the polyethylene composition,

A ₁ represents the ratio (A ₁ , %) of the integral value of the area where the Log MW value is less than 3 to the total integral value on the x-axis in the GPC curve graph where the x-axis is log MW and the y-axis is dw/dlogMw,

A ₂ represents the ratio (A ₂ , %) of the integral value of the area where the Log MW value is 3 or more to less than 3.5 in the GPC curve graph where the x-axis is log MW and the y-axis is dw/dlogMw among the total integral values on the x-axis. will be.

Additionally, the present invention provides a method for producing the polyethylene composition.

Additionally, the present invention provides an injection molded article containing the polyethylene composition.

According to the present invention, a polyethylene composition capable of reducing the generation of harmful gases such as total volatile organic compounds (TVOC) and fumes that may be generated by low molecular weight polymers and a method for producing the same are provided.

Figure 1 is a schematic diagram illustrating an apparatus and process for manufacturing the polyethylene composition of Example 1 according to an embodiment of the invention.

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

Additionally, the terminology used herein is only used to describe exemplary embodiments and is not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as “comprise,” “comprise,” or “have” are intended to designate the presence of implemented features, numbers, steps, components, or a combination thereof, and are intended to indicate the presence of one or more other features or It should be understood that this does not exclude in advance the possibility of the presence or addition of numbers, steps, components, or combinations thereof.

In addition, the terms "about", "substantially", etc. used throughout this specification are used to mean at or close to that value when manufacturing and material tolerances inherent in the stated meaning are presented, and are used herein to To facilitate understanding, precise or absolute figures are mentioned and are used to prevent unscrupulous infringers from taking unfair advantage of the disclosure.

In addition, in this specification, “part by weight” refers to a relative concept expressed as a ratio of the weight of the remaining material based on the weight of a certain material. For example, in a mixture containing 50 g of substance A, 20 g of substance B, and 30 g of substance C, the amounts of substance B and substance C would each be 40 parts by weight based on 100 parts by weight of substance A. parts by weight and 60 parts by weight.

In addition, “% by weight” refers to 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 material A, material B, and material 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 be subject to various changes and can take various forms, specific embodiments will be illustrated and described in detail below. However, this is not intended to limit the present invention to a specific disclosed form, and should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention.

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

According to one embodiment of the invention, it is possible to manufacture a molded article that can secure excellent environmental stress crack resistance, while eliminating harmful substances such as total volatile organic compounds (TVOC) and fumes that may be generated by low molecular weight polymers. Polyethylene compositions capable of reducing gassing are provided.

Specifically, the polyethylene composition of the present invention has a linear structure fraction ratio (R _OL ) of 10% or less and a molecular weight distribution (Mw/Mn) of 12 or less according to Equation 1 below.

[Equation 1]

R _OL = (A ₁ /A ₂ ) × 100

In equation 1 above,

R _OL represents the linear structure fraction ratio (%) contained in the polyethylene composition,

A ₁ represents the ratio (A ₁ , %) of the integral value of the area where the Log MW value is less than 3 to the total integral value on the x-axis in the GPC curve graph where the x-axis is log MW and the y-axis is dw/dlogMw,

A ₂ represents the ratio (A ₂ , %) of the integral value of the area where the Log MW value is 3 or more to less than 3.5 in the GPC curve graph where the x-axis is log MW and the y-axis is dw/dlogMw among the total integral values on the x-axis. will be.

In particular, the polyethylene composition is characterized by a large difference between the area where the Log MW value is 3 or more and less than 3.5 and the area where the Log MW value is less than 3 in the GPC curve graph where the x-axis is log MW and the y-axis is dw/dlogMw. This means that the area of less than log MW 3.0 or log MW 2.5 to 3.0, which is the molecular weight at which volatile organic compounds (VOCs) are generated, is significantly small. As can be seen in the examples described later, by minimizing the ratio of low molecular weight regions (linear polyethylene) measured through GC-Mass, the amount of volatile organic compounds (VOC) generated can be significantly reduced.

Specifically, the linear structure fraction ratio (R _OL ) according to Equation 1 is 10% or less, or 3.0% to 10.0%, or 9.9% or less, or 4% to 9.9%, or 9.8% or less, or 5% to 9.8%, Or it may be 9.6% or less, or 7% to 9.6%, or 9.5% or less, or 7.5% to 9.5%.

In addition, in a GPC curve graph where the x-axis is log MW and the y-axis is dw/dlogMw, the ratio (A ₁ ) of the integral value in the area where the Log MW value is less than 3 to the total integral value on the x-axis is 0.5% or less or 0.01%. It may be from 0.5% to 0.5%, or 0.45% or less, or 0.03% to 0.45%, or 0.43% or less, or 0.02% to 0.43%, or 0.4% or less, or 0.05% to 0.4%.

In addition, in a GPC curve graph where the x-axis is log MW and the y-axis is dw/dlogMw, the ratio (A ₂ ) of the integral value in the area where the Log MW value is 3 or more to less than 3.5 of the total integral value on the x-axis is 3.5% to 3.5%. It may be 4.5%, or 3.6% to 4.4%, or 3.7% to 4.4%, or 3.8% to 4.3%.

In addition, in the GPC curve graph where the x-axis is log MW and the y-axis is dw/dlogMw, the ratio of the integral value of the area where the Log MW value is less than 3 to the total integral value on the x-axis (A ₁ ) and the Log MW value of 3 The difference (A ₂ -A ₁ ) between the ratio (A ₂ ) of the integral value in the area between more than 3.5 and the overall integral value on the x-axis is 3.0% to 4.0%, or 3.2% to 4.0%, or 3.3% to 3.9. %, or 3.5% to 3.9%.

In addition, in a GPC curve graph where the x-axis is log MW and the y-axis is dw/dlogMw, the ratio (A ₃ ) of the integral value in the area where the Log MW value is 5.5 or more out of the total integral value on the x-axis is 11.5% or more or 11.5%. to 18%, or 11.8% or more, or 11.8 % to 17%, or 12% or more, or 12 % to 16%, or 12.3% or more, or 12.3 % to 15%, or 12.5% or more, or 12.5% to 14%. .

The polyethylene composition optimizes the molecular structure to ensure excellent environmental stress cracking resistance when manufacturing injection molded products such as food and drug storage containers or stoppers, while minimizing the amount of volatile organic compounds (VOC) generated, and the GPC curve as described above. The graph has an area ratio. In particular, when minimizing the ratio between specific regions while reducing the low molecule region in the GPC curve graph, uniform physical properties and excellent processability can be secured while reducing VOC.

Meanwhile, as will be described later, the polyethylene composition of the present invention is manufactured using a catalyst containing a specific metallocene compound, so that the chain propagation and chain transfer rates are almost constant and the molecular weight distribution is narrow. It has features.

Specifically, the polyethylene composition may have a molecular weight distribution (Mw/Mn) of 12 or less, or 8.0 to 12.0, or 11.9 or less, or 8.5 to 11.9, or 11.8 or less, or 9 to 11.8, or 11.5 or less, or 10 to 11.5. As described above, the polyethylene composition can effectively reduce TVOC due to low molecular weight in the injection processing process for manufacturing molded products through narrow molecular weight distribution.

Additionally, the polyethylene composition may have a weight average molecular weight of 125,000 g/mol to 250,000 g/mol, or 130,000 g/mol to 180,000 g/mol, or 135,000 g/mol to 150,000 g/mol.

In the present invention, the weight average molecular weight (Mw) and number average molecular weight (Mn) are converted values for standard polystyrene measured using gel permeation chromatography (GPC, manufactured by Water). However, the weight average molecular weight is not limited to this and can be measured by other methods known in the technical field to which the present invention pertains.

Additionally, the polyethylene composition is a high-density polyethylene composition having a density (ASTM D 1505, 23°C) of 0.945 g/cm ³ to 0.965 g/cm ³ . The density is preferably 0.950 g/cm ³ to 0.963 g/cm ³ , or 0.952 g/cm ³ to 0.962 g/cm ³ , or 0.953 g/cm ³ to 0.960 g/cm ³ , or 0.953 g/cm It may be ³ to 0.958 g/cm ³ , or 0.954 g/cm ³ to 0.958 g/cm ³ .

In addition, the polyethylene composition has a melt index (ASTM D 1238, 190° C., 2.16 kg) of 0.01 g/10min to 0.45 g/10min, or 0.05 g/10min to 0.4 g/10min, or 0.1 g/10min to 0.38 g. /10min, or 0.2 g/10min to 0.36 g/10min, or 0.25 g/10min to 0.35 g/10min.

In addition, the composition may have a melt flow rate ratio (MFRR) of MI ₅ /MI _2.16 of 4.2 or more, or 4.2 to 5, or 4.22 or more, or 4.22 to 4.8, or 4.24 or more, or 4.24 to 4.5.

Additionally, the polyethylene composition may have a melting point (Tm) of 128°C to 135°C, or 128.5°C to 134°C, or 129°C to 132°C.

For example, the melting point (Tm) of the polyethylene composition can be measured using a differential scanning calorimeter (DSC). For example, as a differential scanning calorimeter (DSC), the melting temperature of the polymer is measured using DSC 2920 (TA instrument). The polyethylene composition is heated to 200°C, maintained for 5 minutes, lowered to 30°C, then increased again, and the top of the DSC curve is measured as Tm. At this time, the temperature rise and fall rates are each 10 ℃/min, and Tm is measured in the second temperature rising section. For specific measurement methods, refer to Test Example 1 described later.

Meanwhile, the polyethylene composition of the present invention includes an ethylene homopolymer and an ethylene copolymer with a C _4-12 alpha-olefin monomer, preferably in a ratio of 99:1 to 99.5 between the ethylene homopolymer and the ethylene copolymer. : Included at a weight ratio of 0.5.

For example, the alpha-olefin is 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene It may be at least one selected from the group consisting of decene, 1-octadecene, and 1-eicocene, and is preferably 1-butene.

In addition, the polyester resin composition according to the present invention optimizes the molecular structure with a narrow molecular weight distribution, thereby reducing the low molecular area in the GPC curve graph and minimizing the ratio between specific areas, thereby providing excellent environmental stress cracking resistance when processing injection molded products. By ensuring this, the generation of harmful gases such as total volatile organic compounds (TVOC) and fumes can be significantly reduced.

As an example, the total volatile organic compounds (TVOC) content of the polyester resin composition measured for 10 minutes at 200 ° C using gas chromatography-mass spectrometry (JTD-GC/MS-02) is 100 ug/ g or less or 0.01 to 100 ug/g, or 90 ug/g or less or 0.1 to 90 ug/g, or 85 ug/g or less or 0.2 to 85 ug/g, or 82 ug/g or less or 0.2 to 82 ug/g g, or less than 75 ug/g or 0.2 to 75 ug/g. The content of such total volatile organic compounds (TVOC) can be measured by applying various methods known as mass spectrometry methods of gaseous elements, and specific measurement methods can be referred to Test Example 1, which will be described later.

Meanwhile, according to another embodiment of the invention, a method for producing the above-described polyethylene composition is provided.

According to another embodiment of the invention, it is possible to manufacture a molded article that can secure excellent environmental stress crack resistance as described above, while eliminating total volatile organic compounds (TVOC) and fumes that can be generated by low molecular weight polymers. ) A method for effectively producing a polyethylene composition that can reduce the generation of harmful gases such as etc. is provided.

The polyethylene composition according to the present invention includes at least one first metallocene compound represented by the following formula (1); It can be prepared by polymerizing ethylene in the presence of at least one second metallocene compound represented by the following formula (2).

[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 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 radical. one, and they may be substituted with hydrocarbons having 1 to 20 carbon atoms;

R ^a and R ^b are the same 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 each independently 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;

n is 1 or 0;

[Formula 2]

In Formula 2,

B is boron,

M is a group 4 transition metal,

R ₁ to R ₄ are each independently hydrogen, C _1-20 alkyl, C _3-20 cycloalkyl, or C _6-20 aryl, or one or more pairs of R ₁ and R ₂ or R ₃ and R _{4 each} They independently combine with each other to form a substituted or unsubstituted C _6-60 aromatic ring,

R ₅ and R ₆ are each independently C _1-20 alkyl, C _3-20 cycloalkyl, or C _6-20 aryl, or R ₅ and R ₆ are combined to form a C _3-60 aliphatic ring, or C _{6 -60} forms an aromatic ring,

X ₁ and X ₂ are each independently C _1-20 alkyl or -O(CO)R', where R' is C _1-20 alkyl,

Q is a substituted or unsubstituted C _2-60 heterocycle containing at least one selected from the group consisting of N, O and S,

Y and Y' are elements constituting Q,

Y is N, O, or S,

Y' is an element of Q adjacent to Y, and is either N or C.

In this specification, unless there is a special limitation, the following terms may be defined as follows.

A hydrocarbyl group is a monovalent functional group obtained by removing a hydrogen atom from a hydrocarbon, and includes an alkyl group, alkenyl group, alkynyl group, aryl group, aralkyl group, aralkenyl group, aralkynyl group, alkylaryl group, and alkenyl group. It may include an aryl group and an alkynylaryl group. And, the hydrocarbyl group having 1 to 30 carbon atoms may be a hydrocarbyl group having 1 to 20 carbon atoms or a hydrocarbyl group having 1 to 10 carbon atoms. As an example, the hydrocarbyl group may be straight chain, branched chain, or cyclic alkyl. More specifically, the hydrocarbyl group having 1 to 30 carbon atoms is methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, tert-butyl group, n-pentyl group, n-hexyl group. Straight-chain, branched-chain, or cyclic alkyl groups such as actual group, n-heptyl group, and cyclohexyl group; Alternatively, it may be an aryl group such as phenyl, biphenyl, naphthyl, anthracenyl, phenanthrenyl, or fluorenyl. Additionally, it may be alkylaryl such as methylphenyl, ethylphenyl, methylbiphenyl, and methylnaphthyl, and may also be arylalkyl such as phenylmethyl, phenylethyl, biphenylmethyl, and naphthylmethyl. Additionally, it may be alkenyl such as allyl, allyl, ethenyl, propenyl, butenyl, and pentenyl.

A hydrocarbyloxy group is a functional group in which a hydrocarbyl group is bonded to oxygen. Specifically, a hydrocarbyloxy group having 1 to 30 carbon atoms may be a hydrocarbyloxy group having 1 to 20 carbon atoms or a hydrocarbyloxy group having 1 to 10 carbon atoms. For example, the hydrocarbyloxy group may be straight chain, branched chain, or cyclic alkyl. More specifically, the hydrocarbyloxy group having 1 to 30 carbon atoms is methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butoxy group, iso-butoxy group, tert-butoxy group, and n-pentoxy group. , straight-chain, branched-chain, or cyclic alkoxy groups such as n-hexoxy group, n-heptoxy group, and cyclohexoxy group; Alternatively, it may be an aryloxy group such as a phenoxy group or a naphthalenoxy group.

Hydrocarbyloxyhydrocarbyl group is a functional group in which one or more hydrogens of the hydrocarbyl group are replaced with one or more hydrocarbyloxy groups. Specifically, a hydrocarbyloxyhydrocarbyl group having 2 to 30 carbon atoms may be a hydrocarbyloxyhydrocarbyl group having 2 to 20 carbon atoms or a hydrocarbyloxyhydrocarbyl group having 2 to 15 carbon atoms. For example, the hydrocarbyloxyhydrocarbyl group may be straight chain, branched chain, or cyclic alkyl. More specifically, the hydrocarbyloxyhydrocarbyl group having 2 to 30 carbon atoms is methoxymethyl group, methoxyethyl group, ethoxymethyl group, iso-propoxymethyl group, iso-propoxyethyl group, iso-propoxyhexyl group, tert-part. Alkoxyalkyl groups such as toxymethyl group, tert-butoxyethyl group, and tert-butoxyhexyl group; Or it may be an aryloxyalkyl group such as a phenoxyhexyl group.

Hydrocarbyl (oxy)silyl group is a functional group in which 1 to 3 hydrogens of -SiH ₃ are replaced with 1 to 3 hydrocarbyl groups or hydrocarbyloxy groups. Specifically, the hydrocarbyl (oxy) silyl group having 1 to 30 carbon atoms may be a hydrocarbyl (oxy) silyl group having 1 to 20 carbon atoms, 1 to 15 carbon atoms, 1 to 10 carbon atoms, or 1 to 5 carbon atoms. More specifically, the hydrocarbyl (oxy)silyl group having 1 to 30 carbon atoms is an alkyl group such as methylsilyl group, dimethylsilyl group, trimethylsilyl group, dimethylethylsilyl group, diethylmethylsilyl group, or dimethylpropylsilyl group. silyl group; Alkoxysilyl groups such as methoxysilyl group, dimethoxysilyl group, trimethoxysilyl group, or dimethoxyethoxysilyl group; It may be an alkoxyalkyl silyl group such as methoxydimethylsilyl group, diethoxymethylsilyl group, or dimethoxypropylsilyl group.

A silylhydrocarbyl group having 1 to 20 carbon atoms is a functional group in which one or more hydrogens of the hydrocarbyl group are replaced with a silyl group. The silyl group may be -SiH ₃ or a hydrocarbyl (oxy)silyl group. Specifically, a silylhydrocarbyl group having 1 to 20 carbon atoms may be a silylhydrocarbyl group having 1 to 15 carbon atoms or a silylhydrocarbyl group having 1 to 10 carbon atoms. More specifically, the silylhydrocarbyl group having 1 to 20 carbon atoms is a silylalkyl group such as -CH ₂ -SiH ₃ ; Alkylsilylalkyl groups such as methylsilylmethyl group, methylsilylethyl group, dimethylsilylmethyl group, trimethylsilylmethyl group, dimethylethylsilylmethyl group, diethylmethylsilylmethyl group, or dimethylpropylsilylmethyl group; Or it may be an alkoxysilylalkyl group such as dimethylethoxysilylpropyl group.

Halogen may be fluorine (F), chlorine (Cl), bromine (Br), or iodine (I).

Additionally, the sulfonate group has the structure of -O-SO ₂ -R ^c , where R ^c may be a hydrocarbyl group having 1 to 30 carbon atoms. Specifically, the sulfonate group having 1 to 30 carbon atoms may be a methane sulfonate group or a phenyl sulfonate group.

The sulfone group having 1 to 30 carbon atoms has the structure of -R ^c' -SO ₂ -R ^c" , where R ^c' and R ^c" are the same or different from each other and are each independently one of a hydrocarbyl group having 1 to 30 carbon atoms. You can. Specifically, the sulfone group having 1 to 30 carbon atoms may be a methylsulfonylmethyl group, a methylsulfonylpropyl group, a methylsulfonylbutyl group, or a phenylsulfonylpropyl group.

In this specification, two adjacent substituents are connected to each other to form an aliphatic or aromatic ring, which means that the atom(s) of the two substituents and the atoms (atoms) to which the two substituents are bonded are connected to each other to form a ring. do. Specifically, an example in which R e and R f of -NR ^e R ^f or -NR ^{e '} R ^{f '} are linked to each other or R ^e' and R ^f' are linked to each other to form an aliphatic ring is piperidinyl (piperidinyl). ) groups, etc., and examples of R e and R f of -NR ^e R ^f or -NR ^{e '} R ^{f '} being connected to each other or R ^e' and R ^f' being connected to each other to form an aromatic ring include Examples include pyrrolyl group.

Meanwhile, the alkyl may be straight-chain or branched-chain 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 chain alkyl; C _3-15 branched chain alkyl; Or it may be C _3-10 branched chain alkyl. More specifically, C _1-20 alkyl is a methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, tert-butyl group, n-pentyl group, or iso-pentyl group, etc. However, it is not limited to this. Meanwhile, in this specification, “iPr” refers to an iso-propyl group.

The cycloalkyl may be cyclic alkyl. Specifically, the C _3-20 cycloalkyl is C _3-20 cyclic alkyl; C _3-15 cyclic alkyl; Or it may be C _3-10 cyclic alkyl. More specifically, cyclopropyl, cyclobutyl, cyclopentyl, 3-methylcyclopentyl, 2,3-dimethylcyclopentyl, cyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, 2,3-dimethylcyclohexyl, Examples include, but are not limited to, 3,4,5-trimethylcyclohexyl, 4-tert-butylcyclohexyl, cycloheptyl, and cyclooctyl. Meanwhile, in this specification, “Cy” refers to cycloalkyl having 3 to 6 carbon atoms.

The alkenyl may be straight chain, branched chain, or cyclic alkenyl. Specifically, the 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. It may be alkenyl, C _3-10 branched chain alkenyl, C _5-20 cyclic alkenyl or C _5-10 cyclic alkenyl. More specifically, C _2-20 alkenyl may be ethenyl, propenyl, butenyl, pentenyl, or cyclohexenyl.

The alkoxy group may be a straight chain, branched chain, or cyclic alkoxy group. Specifically, the C _1-20 alkoxy is a C _1-20 straight chain alkoxy group; C _1-10 straight chain alkoxy; C _1-5 straight chain alkoxy group; C _3-20 branched or cyclic alkoxy; C _3-15 branched or cyclic alkoxy; Or it may be C _3-10 branched or cyclic alkoxy. More specifically, C _1-20 alkoxy is methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butoxy group, iso-butoxy group, tert-butoxy group, n-pentoxy group, iso- A pentoxy group, a neo-pentoxy group, or a cyclohexoxy group may be included, but are not limited thereto.

The alkoxyalkyl has a structure including -R ^g -OR ^h and may be a substituent in which one or more hydrogens of alkyl (-R ^g ) are replaced with alkoxy (-OR ^h ). Specifically, the C _2-20 alkoxyalkyl is methoxymethyl group, methoxyethyl group, ethoxymethyl group, iso-propoxymethyl group, iso-propoxyethyl group, iso-propoxyhexyl group, tert-butoxymethyl group, tert- There is a butoxyethyl group or a tert-butoxyhexyl group, but it is not limited thereto.

The aryl includes monocyclic, bicyclic or tricyclic aromatic hydrocarbons. According to one embodiment of the present invention, the aryl group may have 6 to 60 carbon atoms, or 6 to 40 carbon atoms, or 6 to 20 carbon atoms, or 6 to 15 carbon atoms, and may be specifically phenyl, biphenyl, naphthyl, anthracenyl, Phenanthrenyl, fluorenyl, etc., but are not limited thereto.

The aryloxy is a functional group in which the above-mentioned aryl group is bonded to oxygen. Specifically, the aryloxy may have 6 to 60 carbon atoms, or 6 to 40 carbon atoms, or 6 to 20 carbon atoms, or 6 to 15 carbon atoms, and more specifically, may include phenoxy, biphenoxyl, naphthoxy, etc., It is not limited to this.

The alkylaryl may refer to a substituent in which one or more hydrogens of the above-described aryl group are replaced by the above-described alkyl. For example, the C _7-20 alkylaryl may include methylphenyl, ethylphenyl, methylbiphenyl, methylnaphthyl, etc., but is not limited thereto.

The arylalkyl may refer to a substituent in which one or more hydrogens of the alkyl described above are replaced by the aryl described above. For example, the C _7-20 arylalkyl may include phenylmethyl, phenylethyl, biphenylmethyl, naphthylmethyl, etc., but is not limited thereto.

In addition, C _6-20 arylene or arylidene is the same as the above-mentioned aryl except that it is a divalent substituent, and is specifically phenylene, biphenylene, naphthylene, anthracenylene, phenanthrenylene, and fluoride. Examples include orenylene, but it is not limited to this.

The heteroaryl is a heteroaryl containing at least one of O, N, and S as a heterogeneous element, and the number of carbon atoms is not particularly limited, but may have 2 to 60 carbon atoms or 2 to 20 carbon atoms. Examples of heteroaryl include xanthene, thioxanthen, thiophene group, furan group, pyrrole group, imidazole group, thiazole group, oxazole group, oxadiazole group, triazole group, pyridyl group, bipyridyl group, Pyridinyl group, pyrimidyl group, triazine group, acridyl group, pyridazine group, pyrazinyl group, quinolinyl group, quinazoline group, quinoxalinyl group, phthalazinyl group, pyrido pyrimidinyl group, pyrido pyrazinyl group, pyrazino pyrazinyl group, isoquinoline group, indole group, carbazole group, benzoxazole group, benzoimidazole group, benzothiazole group, benzocarbazole group, benzothiophene group, dibenzothiophene group, benzofuranyl group, Examples include phenanthroline group, isoxazolyl group, thiadiazolyl group, phenothiazinyl group, and dibenzofuranyl group, but are not limited to these.

In addition, the heterocycle includes both an aliphatic ring containing at least one selected from the group consisting of N, O, and S, and an aromatic ring containing at least one selected from the group consisting of N, O, and S. do.

And, the Group 4 transition metal may be titanium (Ti), zirconium (Zr), hafnium (Hf), or rutherphodium (Rf), and specifically, titanium (Ti), zirconium (Zr), or hafnium (Hf). It may be, and more specifically, it may be zirconium (Zr) or hafnium (Hf), but it is not limited thereto.

Additionally, the Group 13 element may be boron (B), aluminum (Al), gallium (Ga), indium (In), or thallium (Tl), and may specifically be boron (B) or aluminum (Al). and is not limited to this.

The above-mentioned substituents are optionally hydroxy groups within the range of achieving the same or similar effects as the desired effect; halogen; alkyl or alkenyl, aryl, alkoxy; Alkyl or alkenyl, aryl, alkoxy containing one or more heteroatoms from groups 14 to 16; Amino; Silyl; Alkylsilyl or alkoxysilyl; Phosphine group; phosphide group; Sulfonate group; and may be substituted with one or more substituents selected from the group consisting of a sulfone group.

A metallocene catalyst for ethylene polymerization of the present invention, comprising at least one first metallocene compound represented by Formula 1 and one or more second metallocene compounds represented by Formula 2 as catalyst precursors. can be used.

Specifically, in Formula 1, M ¹ may be zirconium (Zr) or hafnium (Hf), and preferably may be zirconium (Zr). Additionally, 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 It can be hydrogen, methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, pentyl, hexyl, butenyl, phenyl, phenyl substituted methyl, phenyl substituted butyl, or tert-butoxyhexyl. Additionally, 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 first metallocene compound represented by Chemical Formula 1 can be synthesized by applying known reactions, and the examples can be referred to for more detailed synthesis methods.

Meanwhile, the polyethylene composition according to the present invention produces ethylene in the presence of a catalyst comprising one or more second metallocene compounds represented by the following formula (2) together with one or more first metallocene compounds described above as catalyst precursors. It can be manufactured by polymerization.

The metallocene compound represented by Chemical Formula 2 adopts a bridge structure containing boron anions, unlike the commonly used CGC (constrained geometry catalyst) type precursor. Conventional CGC-type precursors contain a neutral bridge structure containing silicon, so that the ligand units have a negative charge. This causes structural limitations, making it difficult to develop various physical properties when manufacturing olefin polymers.

On the other hand, the metallocene compound represented by Formula 2 according to the present invention has a negatively charged bridge structure and may have a neutral ligand unit. The ligand unit of the present invention is a heterocyclic ring Q of the above formula (2), where Y, an element of Q, coordinates with a metal, and Y', an element of Q adjacent to Y, is connected to a bridge. Accordingly, in the present invention, a catalyst having higher activity and higher copolymerization than existing CGC precursors can be manufactured by employing various neutral ligand units satisfying the above structure.

In addition, the metal substituent of the metallocene compound represented by Formula 2 includes alkyl or carboxylate, which acts as a good leaving group and promotes reaction with cocatalysts such as MAO, thereby increasing activity.

Specifically, in Formula 2, M may be zirconium (Zr).

In addition, in Formula 2, R ₁ to R ₄ are each independently hydrogen, C _1-10 alkyl, or C _6-20 aryl, or R ₁ to R ₄ are substituted or unsubstituted by combining one or more pairs of them with each other. It can form a ringed C _6-20 aromatic ring. For example, R ₁ and R ₂ or R ₃ and R ₄ may each independently combine with each other to form a substituted or unsubstituted C _6-20 aromatic ring, or R ₁ and R ₂ may combine with each other to form a substituted or unsubstituted ring. An unsubstituted C _6-20 aromatic ring may be formed, and R ₃ and R ₄ may be combined with each other to form a substituted or unsubstituted C _6-20 aromatic ring. Preferably, R ₁ to R ₄ are each independently hydrogen or methyl, or one or more pairs of R ₁ and R ₂ or R ₃ and R ₄ are each independently bonded to each other to form a benzene ring, or 1,2, Can form a 3,4-tetrahydronaphthalene ring, wherein the benzene ring or 1,2,3,4-tetrahydronaphthalene ring is unsubstituted or a group consisting of methyl, tertbutyl and 4-tertbutyl phenyl. It may be substituted with 1 to 4 substituents selected from.

Additionally, in Formula 2, R ₅ and R ₆ are each independently C _1-10 alkyl, or C _6-20 aryl, or R ₅ and R ₆ are bonded to each other to form a C _3-20 aliphatic ring, or C _{6 -20} Can form an aromatic ring. Preferably, R ₅ and R ₆ are each independently methyl or phenyl, or R ₅ and R ₆ may be combined with each other to form a cyclooctane ring.

More preferably, R ₅ and R ₆ may each be phenyl.

Additionally, in Formula 2, X ₁ and X ₂ may each independently be methyl or acetate.

Additionally, in Formula 2, R' may be methyl.

Additionally, in Formula 2, X ₁ and X ₂ may be the same.

Additionally, in Formula 2, Q may be a substituted or unsubstituted C _2-20 heterocycle containing one or more elements selected from the group consisting of N, O, and S. Preferably, Q may be a pyridine ring, quinoline ring, 4,5-dihydroxazole ring, pyrazole ring, or benzoxazole ring, wherein Q is unsubstituted or methyl, isopropyl and diphenylamino It may be substituted with 1 to 4 substituents selected from the group consisting of. More preferably, Q may be a pyridine ring, 4,5-dihydroxazole ring, pyrazole ring, or benzoxazole ring, wherein Q is unsubstituted or consists of methyl, isopropyl and diphenylamino. It may be substituted with 1 to 4 substituents selected from the group.

Additionally, in Formula 2, Y is a heteroatom that coordinates with the metal M, and preferably, Y may be N.

Meanwhile, specific examples of the second metallocene compound represented by Formula 2 include compounds represented by the following structural formulas, but the present invention is not limited thereto:

.

.

The second metallocene compound represented by Chemical Formula 2 can be synthesized by applying known reactions, and the Examples can be referred to for more detailed synthesis methods.

The molar ratio of the first metallocene compound and the second metallocene compound (first metallocene compound: second metallocene compound) is 1:2 to 1:5, or 1:2 to 1:4, or 1:2 to 1:3, or 1:2 to 1:2.5. The molar ratio of the catalyst precursor may be the molar ratio described above in terms of optimizing the molecular structure according to the deviation of the molecular weight of the precursor.

In particular, in the present invention, the metallocene catalyst is a mixture of one or more first metallocene compounds represented by Formula 1 and one or more second metallocene compounds represented by Formula 2. It is a catalyst. When a supported metallocene catalyst is used, the morphology and physical properties of the produced polyethylene are excellent, and it can be suitably used in conventional slurry polymerization, bulk polymerization, and gas phase polymerization processes.

Specifically, the carrier may be a carrier having a highly reactive hydroxyl group, silanol group, or siloxane group on the surface. For this purpose, the carrier is surface modified by calcination or has moisture removed from the surface by drying. can be used For example, silica prepared by calcining silica gel, silica dried at high temperature, silica-alumina, and silica-magnesia can be used, and these are typically Na ₂ O, K ₂ CO ₃ , BaSO ₄ , and Mg(NO ₃ ) ₂ It may contain oxides, carbonates, sulfates, and nitrates.

The temperature during calcination or drying of the carrier may be about 200°C to about 600°C, or about 250°C to about 600°C. If the calcination or drying temperature for the carrier is low, there is a risk that the moisture remaining on the carrier may react with the cocatalyst because there is too much moisture remaining on the carrier, and the cocatalyst support rate is relatively low due to the excessive presence of hydroxyl groups. It can be higher, but this results in a large amount of cocatalyst being required. In addition, if the drying or calcining temperature is too high, the pores on the surface of the carrier merge and the surface area decreases, many hydroxy groups or silanol groups disappear from the surface, and only siloxane remains, which raises the risk of reducing the reaction site with the cocatalyst. there is.

The amount of hydroxyl groups on the surface of the carrier is preferably 0.1 mmol/g to 10 mmol/g, and more preferably 0.5 mmol/g to 5 mmol/g. The amount of hydroxy groups on the surface of the carrier can be adjusted by the preparation 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 be caused by moisture other than the hydroxy group present on the surface of the carrier particle. not.

For example, the amount of hydroxy groups on the surface of the carrier may be 0.1 mmol/g to 10 mmol/g or 0.5 mmol/g to 5 mmol/g. The amount of hydroxy groups on the surface of the carrier can be adjusted by the preparation 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 too low, there are few reaction sites with the cocatalyst, and if it is too large, it may be caused by moisture other than the hydroxy group present on the surface of the carrier particle.

Among the above-mentioned carriers, silica, especially silica manufactured by calcining silica gel, is supported by chemically bonding the functional group of the silica carrier and the compound of formula 1, so that almost no catalyst is released from the surface of the carrier during the propylene polymerization process. As a result, fouling that occurs on the reactor wall or between polymer particles can be minimized when producing polyethylene through slurry or vapor phase polymerization.

In addition, when supported on a carrier, the total amount of the first metallocene compound of Formula 1 and the second metallocene compound of Formula 2 is about 10 μmol or more per weight of the carrier, for example, based on about 1 g of silica, Alternatively, it may be supported in a content range of about 30 μmol or more, about 100 μmol or less, or about 80 μmol or less. When supported in the above content range, it exhibits appropriate supported catalyst activity, which can be advantageous in terms of maintaining the activity of the catalyst and economic efficiency.

In addition, the catalyst composition may further include one or more cocatalysts along with the metallocene compound and carrier described above.

The cocatalyst can be any cocatalyst used when polymerizing olefins under a general metallocene catalyst. This cocatalyst causes a bond to be created between the hydroxyl group in the carrier and the Group 13 transition metal. In addition, since the cocatalyst exists only on the surface of the carrier, it can contribute to securing the unique characteristics of the specific hybrid catalyst composition without fouling phenomenon in which polymer particles stick to the reactor wall or each other.

Additionally, the catalyst composition according to the present invention may include, in addition to the metallocene compound, one or more cocatalyst compounds selected from the group consisting of compounds represented by Formulas 3 to 5 below.

[Formula 3]

-[Al(R ₃₁ )-O] _m -

In Formula 3 above,

R ₃₁ is each independently halogen; or C _1-20 hydrocarbyl substituted or unsubstituted with halogen;

m is an integer greater than or equal to 2,

[Formula 4]

D(R ₄₁ ) ₃

In Formula 4 above,

D is aluminum or boron;

R ₄₁ is each independently halogen; or C _1-20 hydrocarbyl substituted or unsubstituted with halogen,

[Formula 5]

[LH] ⁺ [EA ₄ ] ^- or [L] ⁺ [EA ₄ ] ^-

In Formula 5 above,

L is a neutral or cationic Lewis base;

[LH] ⁺ is Bronsted acid;

E is a group 13 element;

A is each independently substituted or unsubstituted C _6-20 aryl or substituted or unsubstituted C _1-20 alkyl, wherein the C _6-40 aryl or C _1-20 alkyl is unsubstituted or halogen, C _{1 -20} alkyl, C _1-20 alkoxy, and C _6-20 aryloxy.

The compound represented by Formula 3 may serve as an alkylating agent and an activator, the compound represented by Formula 4 may serve as an alkylating agent, and the compound represented by Formula 5 may serve as an activator. there is.

The compound represented by Formula 3 is not particularly limited as long as it is alkylaluminoxane, but may be, for example, methylaluminoxane, ethylaluminoxane, isobutylaluminoxane, butylaluminoxane, etc., and is preferably methylaluminoxane. .

The compound represented by Formula 4 is not particularly limited as long as it is an alkyl metal compound, but for example, trimethyl aluminum, triethyl aluminum, triisobutyl aluminum, tripropyl aluminum, tributyl aluminum, dimethyl chloroaluminum, triisopropyl aluminum, Tri-s-butyl aluminum, tricyclopentyl aluminum, tripentyl aluminum, triisopentyl aluminum, trihexyl aluminum, trioctyl aluminum, ethyldimethyl aluminum, methyldiethyl aluminum, triphenyl aluminum, tri-p-tolyl aluminum, dimethyl It may be aluminum methoxide, dimethyl aluminum ethoxide, trimethyl boron, triethyl boron, triisobutyl boron, tripropyl boron, tributyl boron, etc., and is preferably selected from trimethyl aluminum, triethyl aluminum, and triisobutyl aluminum. You can.

Examples of compounds represented by Formula 5 include triethylammonium tetraphenylboron, tributylammonium tetraphenylboron, trimethylammonium tetraphenylboron, tripropylammonium tetraphenylboron, and trimethylammonium tetra(p-tolyl). Boron, trimethylammonium tetra(o,p-dimethylphenyl)boron, tributylammonium tetra(p-trifluoromethylphenyl)boron, trimethylammonium tetra(p-trifluoromethylphenyl)boron, tributylammonium tetra Pentafluorophenylboron, N,N-diethylaniliniumtetraphenylboron, N,N-dimethylaniliniumtetrapentafluorophenylboron, N,N-diethylammoniumtetrapentafluorophenylboron, trimethylanilinium tetrapentafluorophenylboron Phenylphosphonium tetraphenyl boron, trimethyl phosphonium tetraphenyl boron, 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 Umtetra (p-trifluoromethylphenyl) aluminum, tributylammonium tetrapentafluorophenyl aluminum, N,N-dimethyl ethylanilinium tetraphenyl aluminum, N,N-dimethylanilinium tetrapentafluorophenyl aluminum , N,N-diethylammonium tetrapenta tetraphenylaluminum, 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, triphenylcarboniumtetrapentafluorophenylboron, etc. Preferably, alumoxane can be used, and more preferably, methylaluminoxane (MAO), which is an alkylaluminoxane, can be used.

In addition, in the catalyst composition, the total amount of the cocatalyst, the first metallocene compound of Formula 1 and the second metallocene compound of Formula 2 is each in a molar ratio of about 1:1 to about 1:10000 (crude catalyst: the total of the first and second metallocene compounds), preferably at a molar ratio of about 1:1 to about 1:1000, more preferably about 1:10 to about 1:10. It can be included at a molar ratio of 1:100. At this time, if the molar ratio is less than about 1, the metal content of the cocatalyst is too small and catalytic active species are not formed well, which may lower activity. If the molar ratio exceeds about 10,000, there is a risk that the metal in the cocatalyst may act as a catalyst poison. there is.

The amount of the cocatalyst supported may be about 3 mmol to about 25 mmol, or about 5 mmol to about 20 mmol, based on 1 g of carrier.

Meanwhile, the catalyst composition includes the steps of supporting a cocatalyst on a carrier; Supporting a metallocene compound on a carrier carrying the cocatalyst; and a carrier on which the cocatalyst and the metallocene compound are supported.

In the above method, the loading conditions are not particularly limited and can be performed within a range well known to those skilled in the art. For example, high-temperature loading and low-temperature loading can be appropriately used. For example, the loading temperature may range from about -30 ^o C to about 150 ^o C, and preferably from about 50 ^o C to about 98 o C. ^o C, or about 55 ^o C to about 95 ^o C. The loading time can be appropriately adjusted depending on the amount of the first metallocene compound to be loaded. The reacted supported catalyst can be used as is by removing the reaction solvent by filtration or distillation under reduced pressure. If necessary, it can be used after Soxhlet filtering with an aromatic hydrocarbon such as toluene.

In addition, the preparation of the supported catalyst may be performed under a solvent or without a solvent. When a solvent is used, usable solvents include aliphatic hydrocarbon solvents with 5 to 12 carbon atoms such as hexane or pentane, aromatic hydrocarbon solvents such as toluene or benzene, hydrocarbon solvents substituted with chlorine atoms such as dichloromethane, diethyl ether or Examples include ether-based solvents such as tetrahydrofuran (THF), and most organic solvents such as acetone and ethyl acetate, with hexane, heptane, toluene, or dichloromethane being preferred. The solvent used here is preferably treated with a small amount of alkyl aluminum to remove a small amount of water or air, which acts as a catalyst poison, and it is also possible to use a cocatalyst.

Meanwhile, the polyethylene composition according to the present invention is manufactured by polymerizing ethylene while adding hydrogen gas in the presence of the metallocene catalyst described above.

The hydrogen gas may be used in an amount of 35 ppm to 250 ppm, or 80 ppm to 200 ppm, or 100 ppm to 190 ppm, or 150 ppm to 180 ppm, based on the weight of ethylene. The hydrogen gas content maintains chain propagation and chain transfer rates almost constant, and along with narrow molecular weight distribution, the content of low molecular regions can be minimized and VOC can be lowered.

The method for producing such a polyethylene composition can be carried out by slurry polymerization using ethylene or ethylene and alpha-olefin as raw materials in the presence of the above-described catalyst composition by applying conventional equipment and contact techniques.

The method for producing polyethylene may copolymerize ethylene and alpha-olefin using a continuous slurry polymerization reactor, a loop slurry reactor, etc., but is not limited thereto.

And, the polymerization temperature may be about 25 ^o C to about 500 ^o C, preferably about 25 ^o C to about 200 ^o C, and more preferably about 50 ^o C to about 150 ^o C. Additionally, the polymerization pressure is from about 1 kgf/cm ² to about 100 kgf/cm ² , preferably from about 1 kgf/cm ² to about 50 kgf/cm ² , and more preferably from about 5 kgf/cm ² to about 30 kgf. It can be / ^cm2 .

In the ethylene polymerization process according to the present invention, the catalyst composition containing the above-described first metallocene compound and the second metallocene compound can exhibit high catalytic activity. For example, the catalyst activity during ethylene polymerization is about 15 kg PE/g·cat when calculated as the ratio of the weight of polyethylene (kg PE) produced per mass (g) of the catalyst composition used based on unit time (hr). ㆍhr or more or about 15 kg PE/g·cat·hr to about 80 kg PE/g·cat·hr. Specifically, the activity of the catalyst composition is about 20 kg PE/g·cat·hr or more, or about 22 kg PE/g·cat·hr or more, or about 23 kg PE/g·cat·hr or more, or about 60 kg PE/g·cat·hr or more. It may be less than or equal to kg PE/g·cat·hr, or less than or equal to about 50 kg PE/g·cat·hr, or less than or equal to about 45 kg PE/g·cat·hr.

The polyethylene composition manufactured by the method of the above-described embodiment exhibits improved mechanical, physical, and chemical properties due to narrow molecular weight distribution and various properties resulting from molecular structure optimization characteristics, and can exhibit excellent injection processability. . In particular, the polyethylene composition can reduce TVOC and fume generation that may be generated by low molecular weight polymers.

Meanwhile, according to another embodiment of the invention, an injection molded article containing the polyethylene composition of the above-described embodiment is provided.

According to another embodiment of the invention, by using the polyethylene composition of the above-described embodiment, while reducing the generation of harmful gases such as total volatile organic compounds (TVOC) and fumes that may be generated by low molecular weight polymers, A molded product is provided that can secure excellent environmental stress crack resistance.

In particular, according to the present invention, by using the polyethylene composition prepared by the above-described method, injection of container lids, etc. with excellent physical and chemical properties even when applying a relatively low injection pressure of 1000 bar to 1500 bar, or 1200 bar to 1480 bar. Molded products can be manufactured.

Additionally, these injection molded products can exhibit excellent physical and chemical properties along with excellent injection processability at low injection pressure.

More specifically, the injection molded product has excellent environmental stress resistance when the polyethylene composition prepared by the method of the above-described embodiment is manufactured into an injection molded product in the form of a bottle cap by injection and continuous compression molding (CCM) method. It can exhibit crack resistance (ESCR) characteristics.

As an example, the injection molded product may have an environmental stress cracking resistance (ESCR) measured according to ASTM D 1693 of 50 hours or more, or 55 hours or more, or 58 hours or more, or 60 hours or more, or 62 hours or more. Specifically, the ESCR properties of the injection molded product are measured according to ASTM D 1693 by exposing to a 5% by weight solution of IGEPAL at a temperature of 42°C and then applying pressure to 5 bar to measure the time (F50hr) for crack generation to occur by 50%. can be evaluated. For more specific measurement methods and measurement conditions, refer to Test Example 1 described later.

The environmental stress cracking resistance (ESCR) of the injection molded product manufactured using the polyethylene composition according to one embodiment of the present invention has very excellent environmental resistance, and thus the reliability of the product is greatly improved by minimizing changes in physical properties due to long-term storage. You can do it.

In addition, the polyester resin composition according to the present invention optimizes the molecular structure with a narrow molecular weight distribution, thereby reducing the low molecular area in the GPC curve graph and minimizing the ratio between specific areas, thereby reducing the total volatile organic compounds (TVOC) when processing injection molded products. ) and fume can be significantly reduced.

Representative examples of such injection molded products include food and drug storage containers and stoppers, for example, lightweight bottle caps, and various other injection molded products.

Meanwhile, the injection molded product of another embodiment described above can be manufactured according to a general injection method, except that the polyethylene composition manufactured by the method of the above embodiment is applied and a relatively low injection pressure is applied. . Additional explanation regarding this will be omitted.

Below, preferred embodiments are presented to aid understanding of the present invention. However, the following examples are provided only to make the present invention easier to understand, and the content of the present invention is not limited thereto.

<Example>

[Manufacture of catalyst precursor]

Synthesis Example 1: Preparation of the first metallocene compound

t-butyl-O-(CH ₂ ) 6 -Cl was prepared using _6- chlorohexanol by the method described in Tetrahedron Lett. 2951 (1988), and cyclopentathidenyl sodium (NaCp) was added to it. By reaction, t-butyl-O-(CH ₂ ) ₆ -C ₅ H ₅ was obtained (yield 60%, bp 80 ^o C/0.1 mmHg).

In addition, t-butyl-O-(CH ₂ ) ₆ -C ₅ H ₅ was dissolved in tetrahydrofuran (THF) at -78 ^o C, n-butyllithium (n-BuLi) was slowly added, and the temperature was raised to room temperature. Afterwards, it was reacted for 8 hours. The synthesized lithium salt solution 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 reacted at room temperature for another 6 hours. I ordered it. All volatile substances were removed by vacuum drying, and hexane was added to the obtained oily liquid material and filtered. After vacuum drying the filter solution, hexane was added to induce precipitate at low temperature (-20 ^o 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 (92% yield).

¹ H-NMR (300 MHz, CDCl ₃ ): δ 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 (300 MHz, CDCl ₃ , ppm): δ 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: Preparation of a second metallocene compound

2-Bromopyridine (1 eq.) was dissolved in tetrahydrofuran (0.1 M), and then n -butyllithium (1 eq.) was slowly added dropwise at -90°C and stirred at the same temperature for 1 hour. Afterwards, chlorodiphenylborane (1 eq.) was dissolved in toluene (0.3 M), and then slowly added dropwise to the first reactant at -78°C and stirred for 1 hour. After stirring at room temperature for 12 hours, the solvent was vacuum dried, toluene was added, solids were removed through a filter, etc., and the remaining liquid was vacuum dried to obtain diphenyl(pyridin-2-yl)borane.

After dissolving the diphenyl(pyridin-2-yl)borane (1 eq.) in tetrahydrofuran (0.1 M), a solution of lithium tetramethylcyclopentadienide (Li(CpMe ₄ ), 1 eq.) in tetrahydrofuran (0.1 M) was cooled at 0°C. It was slowly added dropwise and stirred at room temperature overnight. After vacuum drying the solvent, toluene/diethyl ether (volume ratio 3/1, 0.3 M) was added and dissolved, and MCl ₄ (1 eq.) was mixed with toluene (0.2 M) and added at -78°C and stirred at room temperature overnight. did. After completion of the reaction, the solvent was vacuum dried, dichloromethane was added, salts were removed through a filter, etc., and the filtrate was vacuum dried and recrystallized by adding dichloromethane/hexane. The produced solid was filtered, vacuum dried, and dichloro{diphenyl(pyridin-2-yl-κ N )(η ⁵ -2,3,4,5-tetramethylcyclopenta-2,4-dien-1-ylidene)borate}zirconium( IV) was obtained.

Dichloro{diphenyl(pyridin-2-yl-κ N )(η ⁵ -2,3,4,5-tetramethylcyclopenta-2,4-dien-1-ylidene)borate}zirconium(IV) (1 eq.) to toluene /diethyl ether (volume ratio 3/1, 0.3 M), a solution of methyl lithium (2 eq.) dissolved in hexane or diethyl ether was slowly added dropwise at -78°C and stirred at room temperature for 12 hours. After completion of the reaction, the solvent was vacuum dried, dichloromethane was added, salts were removed through a filter, etc., and the filtrate was vacuum dried and recrystallized by adding dichloromethane/hexane. The resulting solid was filtered and vacuum dried to obtain a precursor compound.

¹ H NMR (500 MHz, CDCl ₃ , ppm): δ 8.32(d, 1H), 8.05(d, 4H), 7.70(t, 1H), 7.42(t, 1H), 7.40(t, 4H), 7.23 (d, 1H), 7.17(t, 2H), 2.08(s, 6H), 1.93(s, 6H) 0.95(s, 6H).

Comparative Synthesis Example 1

(1) Preparation of Ligand A

A 1-benzothiophene solution was prepared by dissolving 4.0 g (30 mmol) of 1-benzothiophene in THF. Then, 14 mL (36 mmol, 2.5 M in hexane) of n-BuLi solution and 1.3 g (15 mmol) of CuCN were added to the 1-benzothiophene solution.

Then, 3.6 g (30 mmol) of tigloyl chloride was slowly added to the solution at -80°C, and the resulting solution was stirred at room temperature for about 10 hours.

Afterwards, 10% HCl was poured into the solution to quench the reaction, and the organic layer was separated with dichloromethane to produce (2E)-1-(1-benzothien-2-yl)-2- as a beige solid. Methyl-2-buten-1-one was obtained.

¹ H NMR (300 MHz, CDCl ₃ , ppm): δ 7.85-7.82 (m, 2H), 7.75 (m, 1H), 7.44-7.34 (m, 2H), 6.68 (m, 1H), 1.99 (m, 3H), 1.92 (m, 3H).

A solution of 5.0 g (22 mmol) of (2E)-1-(1-benzothien-2-yl)-2-methyl-2-buten-1-one prepared above was dissolved in 5 mL of chlorobenzene and heated vigorously. 34 mL of sulfuric acid was slowly added to the solution while stirring gently. Then, the solution was stirred at room temperature for about 1 hour. Afterwards, ice water was poured into the solution, and the organic layer was separated with an ether solvent to produce 1,2-dimethyl-1,2-dihydro-3H-benzo[b]cyclopenta[d]thiophen-3-one as a yellow solid. 4.5 g (91% yield) was obtained.

¹ H NMR (300 MHz, CDCl ₃ , ppm): δ 7.95-7.91 (m, 2H), 7.51-7.45 (m, 2H), 3.20 (m, 1H), 2.63 (m, 1H), 1.59 (d, 3H), 1.39 (d, 3H).

Dissolve 2.0 g (9.2 mmol) of 1,2-dimethyl-1,2-dihydro-3H-benzo[b]cyclopenta[d]thiophen-3-one in a mixed solvent of 20 mL of THF and 10 mL of methanol. 570m g (15 mmol) of NaBH ₄ was added to the solution at 0°C. Then, the solution was stirred at room temperature for about 2 hours. Afterwards, HCl was added to the solution to adjust the pH to 1, and the organic layer was separated with an ether solvent to obtain an alcohol intermediate.

A solution was prepared by dissolving the alcohol intermediate in toluene. Then, 190 m g (1.0 mmol) of p-toluenesulfonic acid was added to the solution and refluxed for about 10 minutes. The obtained reaction mixture was separated by column chromatography, showing an orange-brown color, and 1.8 g (9.0 mmol, 98%) of liquid 1,2-dimethyl-3H-benzo[b]cyclopenta[d]thiophene (Ligand A). % yield) was obtained.

¹ H NMR (300 MHz, CDCl ₃ , ppm): δ 7.81 (d, 1H), 7.70 (d, 1H), 7.33 (t, 1H), 7.19 (t, 1H), 6.46 (s, 1H), 3.35 (q, 1H), 2.14 (s, 3H), 1.14 (d, 3H).

(2) Preparation of Ligand B

Add 13 mL (120 mmol) of t-butylamine and 20 mL of ether solvent to a 250 mL Schlenk flask, and add (6-tert-butoxyhexyl) dichloro(methyl) to this flask and another 250 mL Schlenk flask. ) 16 g (60 mmol) of silane and 40 mL of ether solvent were added to prepare a t-butylamine solution and a (6-tert-butoxyhexyl)dichloro(methyl)silane solution, respectively. Then, the t-butylamine solution was cooled to -78°C, and then (6-tert-butoxyhexyl)dichloro(methyl)silane solution was slowly injected into the cooled solution and stirred at room temperature for about 2 hours. did. The resulting white suspension is filtered to obtain an ivory color, and the liquid 1-(6-(tert-butoxy)hexyl)-N-(tert-butyl)-1-chloro-1-methylsilanamine (ligand B) was obtained.

¹ H NMR (300 MHz, CDCl ₃ , ppm): δ 3.29 (t, 2H), 1.52-1.29 (m, 10H), 1.20 (s, 9H), 1.16 (s, 9H), 0.40 (s, 3H) .

(3) Cross-linking of ligands A and B

Add 1.7 g (8.6 mmol) of 1,2-dimethyl-3H-benzo[b]cyclopenta[d]thiophene (Ligand A) to a 250 mL Schlenk flask, and add 30 mL of THF to obtain the ligand. Solution A was prepared. After cooling the Ligand A solution to -78°C, 3.6 mL (9.1 mmol, 2.5 M in hexane) of n-BuLi solution was added to the Ligand A solution and stirred at room temperature overnight to form a purple-brown solution. got it Solution A was prepared by replacing the solvent in the purple-brown solution with toluene, and adding 39 m g (0.43 mmol) of CuCN dispersed in 2 mL of THF to this solution.

Meanwhile, solution B prepared by injecting 1-(6-(tert-butoxy)hexyl)-N-(tert-butyl)-1-chloro-1-methylsilanamine (ligand B) and toluene into a 250 mL schlenk flask. was cooled to -78°C. Solution A prepared previously was slowly injected into the cooled solution B. Then, the mixture of solutions A and B was stirred at room temperature overnight. Then, the produced solid is removed by filtration to produce 1-(6-(tert-butoxy)hexyl)-N-(tert-butyl)-1-(1,2-dimethyl), a brown-colored and viscous liquid. 4.2 g (> 99% yield) of -3H-benzo[b]cyclopenta[d]thiophen-3-yl)-1-methylsilanamine (cross-linked product of ligands A and B) was obtained.

In order to confirm the structure of the cross-linked products of the ligands A and B, the cross-linked products were lithiated at room temperature, and then H-NMR spectra were obtained using a sample dissolved in a small amount of pyridine-D5 and CDCl ₃ .

¹ H NMR (300 MHz, pyridine-D5 and CDCl ₃ , ppm): δ 7.81 (d, 1H), 7.67 (d, 1H), 7.82-7.08 (m, 2H), 3.59 (t, 2H), 3.15 ( s, 6H), 2.23-1.73 (m, 10H), 2.15 (s, 9H), 1.91 (s, 9H), 1.68 (s, 3H).

(4) Preparation of transition metal compounds

1-(6-(tert-butoxy)hexyl)-N-(tert-butyl)-1-(1,2-dimethyl-3H-benzo[b]cyclopenta[d]thiophene in a 250 mL schlenk flask 4.2 g (8.6 mmol) of -3-yl)-1-methylsilanamine (cross-linked product of ligands A and B) was added, and 14 mL of toluene and 1.7 mL of n-hexane were injected into the flask to dissolve the cross-linked product. After cooling this solution to -78°C, 7.3 mL (18 mmol, 2.5 M in hexane) of n-BuLi solution was injected into the cooled solution. Then, the solution was stirred at room temperature for about 12 hours. Next, 5.3 mL (38 mmol) of trimethylamine was added to the solution, and the solution was stirred at about 40° C. for about 3 hours to prepare solution C.

Meanwhile, 2.3 g (8.6 mmol) of TiCl ₄ (THF) ₂ and 10 mL of toluene were added to a separately prepared 250 mL schlenk flask to prepare solution D in which TiCl ₄ (THF) ₂ was dispersed in toluene. Solution C prepared previously was slowly injected into solution D at -78°C, and the mixture of solutions C and D was stirred at room temperature for about 12 hours. Afterwards, the solution was reduced in pressure to remove the solvent, and the obtained solute was dissolved in toluene. Then, the solid not dissolved in toluene was removed by filtration, and the solvent was removed from the filtered solution to obtain 4.2 g (83% yield) of the transition metal compound in the form of a brown solid.

¹ H NMR (300 MHz, CDCl ₃ , ppm): δ 8.01 (d, 1H), 7.73 (d, 1H), 7.45-7.40 (m, 2H), 3.33 (t, 2H), 2.71 (s, 3H) , 2.33 (d, 3H), 1.38 (s, 9H), 1.18 (s, 9H), 1.80-0.79 (m, 10H), 0.79 (d, 3H).

[Manufacture of supported catalyst]

Preparation Example 1: Preparation of supported catalyst

5.0 kg of toluene solution was added to a 20 L stainless steel (sus) high pressure reactor, and the reactor temperature was maintained at 40 ^o C. 1000 g of silica (SP948, manufactured by Grace Davison, Inc.) dehydrated by applying vacuum for 12 hours at a temperature of 600 ^o C was added to the reactor, and after sufficiently dispersing the silica, 0.1 mole of the metallocene compound of Synthesis Example 1 was added to toluene. It was dissolved, added, and stirred at 40 ^o C at 200 rpm for 2 hours to react. Afterwards, stirring was stopped, settling was performed for 30 minutes, and the reaction solution was decantated.

2.5 kg of toluene was added to the reactor, and 9.4 kg of 10 wt% methylaluminoxane (MAO)/toluene solution was added, and then stirred at 40 ^o C and 200 rpm for 12 hours. After the reaction, stirring was stopped, settling was performed for 30 minutes, and the reaction solution was decantated. 3.0 kg of toluene was added and stirred for 10 minutes, then stirring was stopped, settling was performed for 30 minutes, and the toluene solution was decantated.

3.0 kg of toluene was added to the reactor, and 0.25 mole of the metallocene compound of Synthesis Example 2 was dissolved in 1 L of toluene solution and added to the reactor, and stirred for 2 hours at 40 ^o C and 200 rpm for reaction. At this time, the ratio between the metallocene compound of Synthesis Example 1 and the metallocene compound of Synthesis Example 2 was 1:2.5 based on the molar ratio. After lowering the reactor temperature to room temperature, stirring was stopped, settling was performed for 30 minutes, and the reaction solution was decantated.

2.0 kg of toluene was added to the reactor and stirred for 10 minutes, then stirring was stopped, settling was performed for 30 minutes, and the reaction solution was decantated.

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. The 1 kg-SiO ₂ hybrid supported catalyst of Preparation Example 1 was prepared by drying under reduced pressure at 40 ^o C for 4 hours.

Comparative Preparation Example 1: Preparation of supported catalyst

Prepared in the same manner as Preparation Example 1, except that the metallocene compound of Synthesis Example 1 and the metallocene compound of Comparative Synthesis Example 1 were used, and the molar ratio of the catalyst precursor (metallocene compound of Synthesis Example 1: Comparative Synthesis The hybrid supported catalyst of Comparative Preparation Example 1 was prepared by adjusting the metallocene compound of Example 1 to a ratio of 1:2.2.

[Preparation of polyethylene composition]

Example 1

The polyethylene composition of Example 1 was prepared by performing a continuous slurry polymerization process using the supported catalyst prepared in Preparation Example 1 using a continuous slurry reactor under the conditions shown in Table 1 below.

Specifically, as shown in Figure 1, a continuous slurry reactor including a first polymerization reactor (R1), a second polymerization reactor (R2), and a post-reactor (Post-R, post-reactor). A polyethylene composition was prepared using the device. First, catalyst 113 mL/h, ethylene input amount 10 kg/h, hydrogen 1.8 g/h, and 1-butene were added to both the first reactor (R1) and the second reactor (R2) of the continuous slurry reactor. It was administered at the same rate of 1.8 mL/min. There was a stirrer in each reactor (R1, R2), and the rotation speed was 250 rpm to 260 rpm. In addition, triethylaluminum (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 in the polymerized powder. At this time, hydrogen, ethylene, and 1-butene were dissolved in gaseous form, and the catalyst, TEAL, and ASA were dissolved in hexane and introduced into the reactor. Thereafter, the powders polymerized in the first reactor (R1) and the second reactor (R2) were mixed in parallel in a post-reactor (Post-R).

Example 2

The polyethylene composition of Example 2 was prepared in the same manner as Example 1, but by performing a continuous slurry polymerization process under the conditions shown in Table 1 below and varying the amount of hydrogen and 1-butene.

Comparative Example 1

A high-density polyethylene (HDPE) product (INEOS CAP508, manufactured by INEOS) using a Ziegler-Natta (Z/N) catalyst was prepared as Comparative Example 1.

Comparative Example 2

A high-density polyethylene (HDPE) product (INEOS CAP602, manufactured by INEOS) using a Ziegler-Natta (Z/N) catalyst was prepared in Comparative Example 2.

Comparative Example 3

A high-density polyethylene (HDPE) product (BOOREALIS MB5568 manufactured by Borealis) using a Ziegler-Natta (Z/N) catalyst was prepared in Comparative Example 3.

Comparative Example 4

A high-density polyethylene (HDPE) product (LG Chemical, LG BE0400) using a Ziegler-Natta (Z/N) catalyst was prepared in Comparative Example 4.

Comparative Example 5

A high-density polyethylene (HDPE) product (LG SM100 manufactured by LG Chemical) manufactured through a mass production process using the metallocene-supported catalyst prepared in Comparative Preparation Example 1 was prepared in Comparative Example 5.

Comparative Example 6

Prepared in the same manner as Example 1, except that the supported catalyst prepared in Comparative Preparation Example 1 was used instead of the supported catalyst of Preparation Example 1, and the hydrogen input amount and 1-butene input amount were adjusted under the conditions shown in Table 1 below. The polyethylene composition of Comparative Example 6 was prepared by performing a continuous slurry polymerization process with different conditions.

Comparative Example 7

The polyethylene composition of Comparative Example 7 was prepared in the same manner as in Comparative Example 6, but by performing a continuous slurry polymerization process under the conditions shown in Table 1 below and varying the amount of hydrogen and 1-butene.

The main polymerization process conditions of the polyethylene composition according to the above-described examples and comparative examples are shown in Table 1 below.

Catalyst or product name ethylene
(kg/hr) hydrogen
(g/hr) 1-butene
(mL/min) activation
(kg PE/g·cat·h) Example 1 Manufacturing Example 1 10 1.5 3.5 23.5 Example 2 Manufacturing Example 1 10 1.8 1.8 24.9 Comparative Example 1 CAP508 - - - - Comparative Example 2 CAP602 - - - - Comparative Example 3 MB5568 - - - - Comparative Example 4 BE0400 - - - - Comparative Example 5 SM100 - - - - Comparative Example 6 Comparative Manufacturing Example 1 10 3.2 4.5 20.0 Comparative Example 7 Comparative Manufacturing Example 1 10 2.8 4.0 21.2

In Table 1, the catalyst activity (kg PE/g·cat·h) was calculated as the ratio of the weight (kg PE) of the polyethylene composition produced per mass (g) of the supported catalyst used based on unit time (h). .

[Evaluation of physical properties of polyethylene compositions and injection molded products]

Test example 1

The physical properties of the polyethylene composition according to the Examples and Comparative Examples and injection molded products using the same were measured in the following manner, and the results are shown in Table 2 below.

Specifically, the polyethylene compositions according to the Examples and Comparative Examples were respectively put into a single-screw extruder (L/D = 20) with a diameter of 35 mm, melt-kneaded and reaction-extruded at a temperature of about 200 ° C., and then cooled to form each A pellet composition was obtained. Furthermore, each of the pellet compositions thus obtained was used to manufacture each injection molded product (Cap) using an injection molding machine set to a temperature of about 240°C.

1) Melt index (MI, g/10 min)

The melt index (MI _2.16 , MI ₅ ) was measured at a temperature of 190 ^o C and load of 2.16 kg and 5 kg, respectively, using the method of ASTM D 1238, and was expressed as the weight (g) of the polymer melted for 10 minutes. .

2) Melt flow rate ratio (MFRR)

Melt flow rate ratio (MFRR, MI ₅ /MI _2.16 ) is the ratio of MI ₅ melt rate (MI, 5 kg load) divided by MI _2.16 (MI, 2.16 kg load).

3) Density

The density (g/cm ³ ) of the polyethylene composition was measured by the method of ASTM D 1505.

4) Melting point (Tm)

Melting point and melting point (Tm) were measured using a differential scanning calorimeter (DSC).

Specifically, the melting temperature of the polymer was measured using a differential scanning calorimeter (DSC), DSC 2920 (TA instrument). The polyethylene composition was heated to 200°C and maintained for 5 minutes, lowered to 30°C, then increased again, and the top of the DSC curve was measured as Tm. At this time, the temperature rise and fall rates were each 10°C/min, and Tm was measured in the second temperature rising section.

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

The weight average molecular weight (Mw) and number average molecular weight (Mn) of polyethylene were measured using gel permeation chromatography (GPC, manufactured by Water), and the weight average molecular weight was divided by the number average molecular weight to obtain molecular weight distribution (PDI). ) was calculated.

Specifically, a Waters PL-GPC220 instrument was used as a gel permeation chromatography (GPC) device, and a 300 mm long column from Polymer Laboratories PLgel MIX-B was used. At this time, the measurement temperature was 160 ^o C, 1,2,4-trichlorobenzene was used as a solvent, and the flow rate was 1 mL/min. The polyethylene samples according to the examples and comparative examples each contained 0.0125% of dibutylhydroxytoluene (BHT, 2,6-bis(1,1-dimethylethyl)-4-methylphenol) using a GPC analysis device (PL-GP220). It was pretreated by dissolving it in 1,2,4-Trichlorobenzene at 160 ^o C for 10 hours, prepared at a concentration of 10 mg/10 mL, and then supplied in an amount of 200 μL. The values of Mw and Mn were derived using a calibration curve formed using a polystyrene standard specimen. The weight average molecular weight of polystyrene standard specimens 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. Nine types of /mol were used.

6) Linear structure fraction ratio

As described above, the linear structure fraction ratio (R _OL ) was calculated from the log graph of the weight average molecular weight (Mw) of polyethylene measured using gel permeation chromatography (GPC, manufactured by Water). did.

Specifically, a log graph of the weight average molecular weight (Mw) of polyethylene measured using a GPC device in the same manner as described above, that is, a GPC curve with log MW on the x-axis and dw/dlogMw on the y-axis. In the graph, the integral value of the area where the Log MW value is less than 3 (logMW < 3, A ₁ ) and the integrated value of the area where the Log MW value is more than 3 but less than 3.5 (3 ≤ logMW ≤ 3.5, A ₂ ), the Log MW value is 5.5 The ratio (%) of the integral value of the region above (5 ≤ logMW, A ₃ ) to the total integral value was calculated. Among these, using the integral value ratio (A ₁ ) of the region where the Log MW value is less than 3 and the integral value ratio (A ₂ ) of the region where the Log MW value is less than 3, respectively, the linear structure fraction ratio (R) according to Equation 1 below _OL ) was calculated and shown in Table 2 below.

[Equation 1]

R _OL = (A ₁ /A ₂ ) × 100

In equation 1 above,

R _OL represents the linear structure fraction ratio (%) contained in the polyethylene composition,

A ₁ represents the ratio (A ₁ , %) of the integral value of the area where the Log MW value is less than 3 to the total integral value on the x-axis in the GPC curve graph where the x-axis is log MW and the y-axis is dw/dlogMw,

A ₂ represents the ratio (A ₂ , %) of the integral value of the area where the Log MW value is 3 or more to less than 3.5 in the GPC curve graph where the x-axis is log MW and the y-axis is dw/dlogMw among the total integral values on the x-axis. will be.

7) Analysis of polymer content in the low molecular area (GC Area)

Polyethylene compositions according to Examples and Comparative Examples were analyzed for polymer content in the low molecular weight region (GC Area) using the following method, and the results are shown in Table 2 below.

1. 10 mL of xylene was added to 0.5 g of a polyethylene composition sample and heated at 140°C.

2. When the polyethylene composition sample was completely melted, it was cooled to room temperature (about 25°C) and then 10 mL of ethanol was added to precipitate the melted sample.

3. After centrifuging the sample, 10 mL of supernatant was taken and dried with N ₂ blow.

4. The dried sample was again dissolved in 1 mL of Chloroform and analyzed by gas chromatography (GC/FID).

5. Process for quantitative analysis:

1) GC/FID conditions:

- Column: HP-5MS (0.32 mm ID x 30 m L, 0.25 mm d.f. capillary)

- Column Flow: 2mL/min

- Oven temperature: 100℃(3min) - 15℃/min-320℃(20min)

- Injection volume: 0.5 uL

- Split ratio: 1/20

6. Calculate the sum of the areas of each peak corresponding to carbon numbers 14 to 32 (C14 to C32) in the gas chromatography (GC/FID) analysis graph (time on the x-axis, abundance on the y-axis) obtained by the above-mentioned method, and calculate the sample Divided by weight. The relative ratio was calculated by converting this to a relative value for the same weight (e.g., 1 g), and the value (GC Area) is shown in Table 2 below.

8) Environmental stress crack resistance (CAP ESCR)

As described above, for injection molded products (Caps) manufactured using polyethylene compositions according to Examples and Comparative Examples, environmental stress crack resistance (CAP ESCR, CAP Environmental Stress Crack Resistance, F50hr) was measured according to ASTM D 1693. did.

Specifically, environmental stress cracking resistance of bent strip in Condition B at 10% IGEPAL, 42℃, using Cap ESCR measuring equipment (IPPS-IM) manufactured by STEINFURTH in accordance with ASTM D 1693, under the following conditions. (Cap Environmental Stress Crack Resistance; Cap ESCR) was measured.

1. As described above, an injection molded cap was used.

2. Cap ESCR measurement equipment (IPPS-IM) manufactured by STEINFURTH was used.

3. After fastening the cap to the preform, it was mounted on the IPPS-IM bench.

4. The Cap was immersed in a 5% Igepal solution and the Cap ESCR was measured at a temperature of 42°C and a pressure of 5 bar.

9) Total volatile organic compounds (TVOC)

Volatile organic compounds (VOC, ug/g) analysis was performed on the polyethylene compositions according to Examples and Comparative Examples at 200°C in the following manner, and the measured value for the polyethylene composition of Example 1 was set as 100%, and the remaining The TVOC relative values (%) for the polyethylene compositions of Example 2 and Comparative Examples 1 to 7 are shown in Table 2 below.

Specifically, volatile organic compound (VOC) analysis was performed using gas chromatography-mass spectrometry (JTD-GC/MS-02) under the following conditions.

1. 20 mg of polyethylene composition sample was placed in a PAT tube.

2. Process for quantitative analysis:

1) JTD condition: Split ratio = 1/100

2) Temperature and time: 200 ℃, 10 minutes

3) GC oven: 50℃ (5 minutes) - 10℃ (25 minutes) - 300℃ (20 minutes)

4) Column: HP-5MS (60m

5) About 17 mg of toluene was diluted in 10 mL MeOH to create a toluene standard solution of about 1.7 ug/uL.

6) 1 uL of the standard solution was injected into Tenax PAT, capped, and analyzed with JTD.

7) PAT containing the sample was analyzed by JTD.

8) Calculation formula VOCcompound = [(Acompound / Astd) x Cstd] / Wsample

9) VOCcompound = VOC value of individual substances generated in the measured sample (ug/g)

A compound = chromatogram area of the peaks of individual substances in the measurement sample

Astd = peak area of toluene standard solution

Cstd = Mass of toluene injected using toluene standard solution (approximately 1.7 ug/g)

Wsample = weight of measured sample (g).

More specifically, the TVOC value measured by the method described above for the polyethylene composition of Example 1 was 80.5 ug/g, and taking this as 100%, the TVOC for the remaining polyethylene compositions of Example 2 and Comparative Examples 1 to 7 Relative values (%) are shown in Table 2 below.

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 MI _2.16 (g/10min) 0.35 0.29 1.8 0.8 0.8 0.27 1.05 0.49 0.42 MI ₅ (g/10min) 1.48 1.24 5.94 2.72 2.92 1.12 4.11 1.99 1.72 MFRR (MI ₅ /MI _2.16 ) 4.24 4.27 3.3 3.4 3.65 4.15 3.91 4.07 4.09 density
(g/ ^cm3 ) 0.954 0.955 0.953 0.953 0.956 0.959 0.951 0.952 0.952 Tm (°C) 130.3 129.3 129.7 129.9 130.4 132.9 128.4 128.1 128.8 MW (x1000 g/mol) 138 150 105 130 133 184 112 121 125 PDI (Mw/Mn) 10.8 11.5 17.4 16.5 22.9 13.8 11.3 12.6 12.8 A ₁ (%) 0.3 0.4 2.8 2.0 3.0 0.7 1.3 0.6 0.7 A ₂ (%) 3.8 4.3 6.0 4.9 6.3 5.4 5.8 5.2 6.9 A ₃ (%) 12.6 13.7 8.7 10.8 10.8 11.7 9.3 10.9 11 A ₂ -A ₁ (%) 3.5 3.9 3.2 2.9 3.3 4.7 4.5 4.6 6.2 R _OL (%) 7.89 9.30 46.67 40.82 47.62 12.96 22.41 11.54 10.14 GC Area 381 419 4741 4077 5324 1720 1148 621 593 ESCR (hrs) 66.3 62.1 14 47.6 47 45.8 16 37.2 40.1 TVOC relative value (%) 100 89 748 589 840 364 344 192 158

As shown in Table 2, the polyethylene composition of the example according to the present invention has a narrow molecular weight distribution and minimizes the linear structure fraction ratio through adjustment of the molecular structure, thereby providing excellent durability when manufacturing injection molded products such as food and drug storage containers or stoppers. It can be seen that while securing environmental stress cracking resistance (Cap ESCR), it is possible to reduce the generation of harmful gases such as total volatile organic compounds (TVOC) and fumes that can be generated by polymers in the low molecular weight region. .

Claims (21)

Containing an ethylene homopolymer and an ethylene copolymer of ethylene and a C _4-12 alpha-olefin monomer at a weight ratio of 99:1 to 99.5:0.5,
The linear structure fraction ratio (R _OL ) according to Equation 1 below is 10% or less,
The molecular weight distribution (Mw/Mn) is 12 or less,
Density (ASTM D 1505, 23°C) is 0.953 g/cm ³ to 0.960 g/cm ³ ,
A melt index (ASTM D 1238, 190° C., 2.16 kg) of 0.25 g/10 min to 0.35 g/10 min,
Polyethylene composition:
[Equation 1]
R _OL = (A ₁ /A ₂ ) × 100
In equation 1 above,
R _OL represents the linear structure fraction ratio (%) contained in the polyethylene composition,
A ₁ represents the ratio (A ₁ , %) of the integral value of the area where the Log MW value is less than 3 out of the total integral value on the x-axis in the GPC curve graph where the x-axis is log MW and the y-axis is dw/dlogMw. A ₁ is 0.5% or less,
A ₂ represents the ratio (A ₂ , %) of the integral value of the area where the Log MW value is 3 or more to less than 3.5 in the GPC curve graph where the x-axis is log MW and the y-axis is dw/dlogMw among the total integral values on the x-axis. Thus, A ₂ is 3.5% to 4.5%,
In a GPC curve graph where the x-axis is log MW and the y-axis is dw/dlogMw, the ratio (A ₃ ) of the integral value in the area where the Log MW value is 5.5 or more out of the total integral value on the x-axis is more than 11.5%,
The molecular weight distribution (Mw/Mn) and GPC curve graph were obtained by gel permeation chromatography using a Polymer Laboratories PLgel MIX-B 300 mm long column and 2,4-trichlorobenzene (1,2,4-Trichlorobenzene) as a solvent. It was obtained by measurement using (GPC, gel permeation chromatography, manufactured by Water).
According to paragraph 1,
wherein the linear structure fraction ratio (R _OL ) is 3.0% to 10.0%,
Polyethylene composition.
According to paragraph 1,
In a GPC curve graph where the x-axis is log MW and the y-axis is dw/dlogMw, the ratio (A ₁ ) of the integral value of the area where the Log MW value is less than 3 to the total integral value on the x-axis is 0.05% to 0.45%,
Polyethylene composition.
According to paragraph 1,
In a GPC curve graph where the x-axis is log MW and the y-axis is dw/dlogMw, the ratio (A ₂ ) of the integral value in the area where the Log MW value is 3 or more to less than 3.5 of the total integral value on the x-axis is 3.6% to 4.4%. person,
Polyethylene composition.
According to paragraph 1,
In a GPC curve graph where the x-axis is log MW and the y-axis is dw/dlogMw, the ratio (A 1 ) of the integral value of the area where the Log MW value is less than 3 to the total integral value on the x-axis (A ₁ ) and the Log MW value of 3 or more The difference (A _{2 -A 1} ) between the ratio (A 2 ) of the integral value of the area less than 3.5 to the total integral value on the x-axis is 3.2% to 4.0%,
Polyethylene composition.
According to paragraph 1,
In a GPC curve graph where the x-axis is log MW and the y-axis is dw/dlogMw, the integral value of the area where the Log MW value is 5.5 or more accounts for 12.5% to 18% of the total integral value on the x-axis (A ₃ ),
Polyethylene composition.
According to paragraph 1,
having a molecular weight distribution (Mw/Mn) of 8.0 to 12.0,
Polyethylene composition.
According to paragraph 1,
a density (ASTM D 1505, 23° C.) of 0.953 g/cm ³ to 0.955 g/cm ³ ,
Polyethylene composition.
According to paragraph 1,
A melt index (ASTM D 1238, 190° C., 2.16 kg) of 0.29 g/10 min to 0.35 g/10 min,
Polyethylene composition.
Ethylene homopolymerization process in the presence of a hybrid supported catalyst comprising at least one first metallocene compound represented by the following formula (1) and one or more second metallocene compounds selected from the compounds represented by the following formula (2) And producing an ethylene homopolymer and an ethylene copolymer with a C _4-12 alpha-olefin monomer through a copolymerization process of ethylene and a C _4-12 alpha-olefin monomer; and
Mixing the ethylene homopolymer and the ethylene copolymer at a weight ratio of 99:1 to 99.5:0.5;
Method for producing the polyethylene composition of claim 1, comprising:
[Formula 1]
(Cp ¹ R ^a ) _n (Cp ² R ^b ) M ¹ Z ¹ _3-n
In Formula 1,
M ¹ is zirconium or hafnium;
Cp ¹ and Cp ² are the same 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 radical. one, and they may be substituted with hydrocarbons having 1 to 20 carbon atoms;
R ^a and R ^b are the same or different from each other, and are each independently hydrogen, C _1-6 alkyl, C _7-12 arylalkyl, C _2-12 alkoxyalkyl, C _6-12 aryl, or C _2-6 alkenyl ego;
Z ¹ is each independently a halogen atom;
n is 1;
[Formula 2]

In Formula 2,
B is boron,
M is zirconium,
R ₁ to R ₄ are each independently hydrogen, C _1-10 alkyl, or C _6-15 aryl, or
One or more pairs of R ₁ and R ₂ or R ₃ and R ₄ are each independently bonded to each other to form a substituted or unsubstituted C _6-20 aromatic ring, and the C _6-20 aromatic ring is unsubstituted or methyl, is substituted with 1 to 4 substituents selected from the group consisting of tertbutyl and 4-tertbutyl phenyl,
R ₅ and R ₆ are each independently C _1-10 alkyl, or C _6-15 aryl, or R ₅ and R ₆ are combined with each other to form a C _3-20 aliphatic ring or a C _6-20 aromatic ring; ,
X ₁ and X ₂ are each independently C _1-10 alkyl or -O(CO)R', where R' is C _1-10 alkyl,
Q is a substituted or unsubstituted pyridine ring, a substituted or unsubstituted quinoline ring, a substituted or unsubstituted 4,5-dihydroxazole ring containing at least one selected from the group consisting of N, O and S. , a substituted or unsubstituted pyrazole ring, or a substituted or unsubstituted benzoxazole ring,
Y and Y' are elements constituting Q,
Y is N, O, or S,
Y' is an element of Q adjacent to Y, and is either N or C.
delete According to clause 10,
The first metallocene compound is a compound represented by any of the following structural formulas,
Method for producing polyethylene composition:

.
delete According to clause 10,
In Formula 2,
R ₁ to R ₄ are each independently hydrogen or methyl, or one or more pairs of R ₁ and R ₂ or R ₃ and R ₄ are each independently bonded to each other to form a benzene ring, or 1,2,3,4- Forms a tetrahydronaphthalene ring,
Here, the benzene ring or 1,2,3,4-tetrahydronaphthalene ring is unsubstituted or substituted with 1 to 4 substituents selected from the group consisting of methyl, tertbutyl, and 4-tertbutyl phenyl. ,
Method for producing polyethylene composition.
According to clause 10,
In Formula 2, R ₅ and R ₆ are each independently methyl or phenyl, or R ₅ and R ₆ are bonded to each other to form a cyclooctane ring.
Method for producing polyethylene composition.
According to clause 10,
In Formula 2, X ₁ and X ₂ are each independently methyl or acetate,
Method for producing polyethylene composition.
According to clause 10,
In Formula 2, Q is unsubstituted or substituted with 1 to 4 substituents selected from the group consisting of methyl, isopropyl, and diphenylamino.
Method for producing polyethylene composition.
According to clause 10,
The second metallocene compound is a compound represented by any of the following structural formulas,
Method for producing polyethylene composition:

.
According to clause 10,
The first metallocene compound and the second metallocene compound are contained in a molar ratio of 1:2 to 1:5.
Method for producing polyethylene composition.
According to clause 10,
The polymerization step is performed by adding hydrogen gas at 35 ppm to 250 ppm based on the molar content of ethylene.
Method for producing polyethylene composition.
An injection molded article comprising the polyethylene composition according to any one of claims 1 to 9.