KR20220153521A - Ethylene/alpha-olefin copolymer and method for preparing the same - Google Patents

Abstract

In the present invention, a pellet type polyethylene resin composition capable of improving pipe resistance, dimensional stability, and processability at the same time and a manufacturing method thereof are provided.

Description

Ethylene/alpha-olefin copolymer and its preparation method {ETHYLENE/ALPHA-OLEFIN COPOLYMER AND METHOD FOR PREPARING THE SAME}

The present invention relates to ethylene/alpha-olefin copolymers and methods for their preparation.

PE-RT (Polyethylene of Raised Temperature resistance) is a material that has enhanced durability at high temperatures, in addition to hygiene and processability, which are the advantages of the existing PE (Polyethylene). In particular, PE-RT type II has been used in various fields for transporting hot water, such as water supply pipes or hot water pipes, because it exhibits high withstand pressure characteristics of MRS (Minimum Required Strength) 9.3 MPa or more at high temperatures without crosslinking.

Durability for long-term use of these PE-RT materials must be guaranteed.

Here, the long-term durability of PE-based polymer materials such as PE-RT can be largely divided into resistance to ductile failure (resistance to pressure) and resistance to brittle fracture.

Ductile failure appears as failure due to local large deformation at relatively high stress. On the other hand, brittle failure proceeds very slowly at relatively low stress, cracks occur, and final failure occurs through slow crack propagation in which the generated crack propagates very slowly.

Resistance to ductile fracture is evaluated through a pressure resistance test (ISO9080), which usually takes 1 year, and the Low Prediction Limit (σ _LPL ) is calculated by extrapolating the stress-life curve to 50 years, based on which the The minimum required strength (MRS), which is a pressure resistance performance rating, is assigned. For example, as a result of a pressure test, if σ _LPL is 10 MPa or more, MRS10 class is given, but if 8 MPa ≤ σ _LPL < 10 MPa, it is MRS8 class.

Since brittle fracture proceeds very slowly in a low stress state, various accelerated evaluation methods have been proposed, and one of them, the Cracked Round Bar (CRB) test method, has been standardized (ISO 18489) to quantitatively compare brittle fracture resistance.

Since resistance to ductile fracture and brittle fracture are in a trade-off relationship with each other, it is necessary to harmonize physical properties that satisfy both of them.

An object of the present invention is to provide an ethylene/alpha-olefin copolymer with improved brittle fracture resistance and a method for preparing the same while maintaining high pressure resistance performance.

In one embodiment of the present invention, an ethylene/alpha-olefin copolymer having a high molecular weight ratio compared to commercially available products is provided.

In another embodiment of the present invention, a method for preparing the ethylene/alpha-olefin copolymer using a specific hybrid supported catalyst is provided.

Another embodiment of the present invention provides a pipe manufactured using the ethylene/alpha-olefin copolymer.

The ethylene/alpha-olefin copolymer according to the embodiment may exhibit excellent brittle fracture resistance due to a high molecular weight ratio compared to commercially available products while maintaining high withstand pressure performance.

The preparation method according to another embodiment may mass-produce the ethylene/alpha-olefin copolymer of the above-described embodiment by using a specific hybrid supported catalyst.

As the pipe according to another embodiment is manufactured using the ethylene/alpha-olefin copolymer of the above-described embodiment, long-term durability may be excellently expressed.

1 shows a molecular weight distribution curve (GPC curve) obtained in Experimental Example 1.
2 schematically shows specimen conditions for measuring brittle fracture resistance in Experimental Example 2.
3 schematically shows the load conditions for measuring brittle fracture resistance in Experimental Example 2.
4 shows an image of a fracture surface of Comparative Example 2 under a maximum fatigue stress of 8.8 MPa during measurement of brittle fracture resistance of Experimental Example 2.
5 shows a life curve according to load conditions during the measurement of brittle fracture resistance of Experimental Example 2.
6 shows the brittle fracture resistance measurement results of Experimental Example 2.
7 shows the evaluation results of σ _LPL and MRS grade in Experimental Example 2.
8 is a graph showing brittle fracture resistance as the x-axis and MRS grade as the y-axis in Experimental Example 2.

Terms used in this specification are only used to describe exemplary embodiments, and are 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 "having" are intended to indicate that there is an embodied feature, step, component, or combination thereof, but one or more other features or steps; It should be understood that the presence or addition of components, or combinations thereof, is not previously excluded.

In the present specification, the following terms may be defined as follows unless otherwise specified.

A hydrocarbyl group is a monovalent functional group obtained by removing a hydrogen atom from a hydrocarbon, and includes an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group, an aralkenyl group, an aralkynyl group, an alkylaryl group, an alkenylaryl group, and an alkynyl group. It may contain a nyl aryl group and the like. In addition, the hydrocarbyl group having 1 to 30 carbon atoms may be a hydrocarbyl group having 1 to 20 carbon atoms or 1 to 10 carbon atoms. 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 n-heptyl group and cyclohexyl group; or an aryl group such as a phenyl group, a naphthyl group, or an anthracenyl group.

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

A hydrocarbyloxyhydrocarbyl group is a functional group in which one or more hydrogens of the hydrocarbyl group are substituted with one or more hydrocarbyloxy groups. Specifically, the hydrocarbyloxyhydrocarbyl group having 2 to 30 carbon atoms may be a hydrocarbyloxyhydrocarbyl group having 2 to 20 carbon atoms or 2 to 15 carbon atoms. More specifically, a hydrocarbyloxyhydrocarbyl group having 2 to 30 carbon atoms is a methoxymethyl group, a methoxyethyl group, an ethoxymethyl group, an iso-propoxymethyl group, an iso-propoxyethyl group, an iso-propoxyhexyl group, a tert-part It may be a oxymethyl group, a tert-butoxyethyl group, a tert-butoxyhexyl group or a phenoxyhexyl group.

A hydrocarbyl (oxy)silyl group is a functional group in which 1 to 3 hydrogens of -SiH ₃ are substituted 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, a hydrocarbyl (oxy)silyl group having 1 to 30 carbon atoms is an alkylsilyl group such as a methylsilyl group, a dimethylsilyl group, a trimethylsilyl group, a dimethylethylsilyl group, a diethylmethylsilyl group, and a dimethylpropylsilyl group. energy; Alkoxysilyl groups, such as a methoxysilyl group, a dimethoxysilyl group, a trimethoxysilyl group, and a dimethoxyethoxysilyl group; and an alkoxyalkylsilyl group such as a methoxydimethylsilyl group, a diethoxymethylsilyl group, and a 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 substituted with a silyl group. The silyl group may be -SiH ₃ or a hydrocarbyl (oxy)silyl group. Specifically, the silyl hydrocarbyl group having 1 to 20 carbon atoms may be a silyl hydrocarbyl group having 1 to 15 carbon atoms or 1 to 10 carbon atoms. More specifically, the silylhydrocarbyl group having 1 to 20 carbon atoms may be -CH ₂ -SiH ₃ , a methylsilylmethyl group, or a dimethylethoxysilylpropyl group.

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

The sulfonate group has a structure of -O-SO ₂ -R ^a , and R ^a may be a hydrocarbyl group having 1 to 30 carbon atoms. Specifically, the sulfonate group having 1 to 30 carbon atoms may be a methanesulfonate group or a phenylsulfonate group.

The sulfone group having 1 to 30 carbon atoms has a structure of -R ^b' -SO ₂ -R ^b" , wherein R ^b' and R ^b" are the same as or different from each other, and each independently may be any one of hydrocarbyl groups having 1 to 30 carbon atoms. 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.

An alkylene group is a divalent functional group obtained by removing two hydrogen atoms from an alkane. Specifically, the alkylene group having 1 to 5 carbon atoms may be a methylene group, an ethylene group, a propylene group, a butylene group or a pentylene group.

In the present specification, two adjacent substituents are linked to each other to form an aliphatic or aromatic ring means that the atom (s) of the two substituents and the atoms (atoms) to which the two substituents are bonded are linked to each other to form a ring. do. Specifically, examples in which R ₉ and R ₁₀ of -NR ₉ R ₁₀ are connected to each other to form an aliphatic ring include a piperidinyl group, and the like, and R ₉ and R ₁₀ of -NR ₉ R ₁₀ are An example in which an aromatic ring is formed by being connected to each other may be a pyrrolyl group or the like.

The above-mentioned substituents are optionally hydroxy groups within the range of exhibiting the same or similar effects to the desired effect; halogen; hydrocarbyl group; Hydrocarbyloxy group; a hydrocarbyl group or a hydrocarbyloxy group containing at least one heteroatom among the heteroatoms of groups 14 to 16; -SiH ₃ ; Hydrocarbyl (oxy) silyl group; phosphine group; phosphide group; sulfonate group; And it may be substituted with one or more substituents selected from the group consisting of sulfone groups.

In addition, in the present specification, 'room temperature' means 20 ± 5 ° C. unless otherwise specifically defined.

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

An object of the present invention is to provide an ethylene/alpha-olefin copolymer with improved brittle fracture resistance and a method for preparing the same while maintaining high pressure resistance performance.

Ethylene/alpha-olefin copolymer

In the present invention, an ethylene/alpha-olefin copolymer having a high molecular weight ethylene/alpha-olefin copolymer having logM≥5.5 of 17% or more in the total ethylene/alpha-olefin copolymer (100%) is provided.

high molecular weight ratio (F _logM≥5.5 )

Brittle fracture is one of the factors determining the long-term durability of PE-based polymer materials such as PE-RT.

Specifically, the brittle fracture resistance of PE-based polymer materials has a great relationship with chain entanglement and disentanglement time of tie-molecules between adjacent lamellas.

The PE-based polymer material is a semi-crystalline polymer and may include a crystalline portion and an amorphous portion. Specifically, the crystalline portion may include lamellar crystals including ethylene repeating units or alpha-olefin repeating units, and a tie molecule serves to mediate bonding between lamellar crystals.

Accordingly, in the PE-based polymer material, as the twist and linking molecules of the chain between adjacent lamellas increase, the entanglement is hindered, and the resistance to brittle fracture increases.

In the above embodiment, an ethylene/alpha-olefin copolymer having a high molecular weight ratio compared to commercially available products is provided in order to increase twist and link molecules of chains between adjacent lamellae.

Specifically, as a result of confirming commercially available products in Experimental Example 1 described later, the ratio of ethylene/alpha-olefin copolymer having logM≥5.5 was 16.4% among all ethylene/alpha-olefin copolymers (100%).

On the other hand, in the present invention, the ratio of ethylene/alpha-olefin copolymer having logM≥5.5 among the total ethylene/alpha-olefin copolymer (100%) is 17% or more, 17.1% or more, 17.2% or more, 17.3% or more, or 17.4% or greater ethylene/alpha-olefin copolymer.

The high molecular weight ratio (F _logM≥5.5 ) contained in the ethylene/alpha-olefin copolymer is obtained through gel permeation chromatography analysis to obtain a molecular weight distribution curve (GPC curve) for the ethylene/alpha-olefin copolymer, It may be a value expressed as a percentage of the area of the fraction having log M≧5.5 out of the total area of the molecular weight distribution curve.

In other words, the ethylene/alpha-olefin copolymer satisfies Equation 1 below:

[Equation 1]

17% ≤ _FlogM≥5.5

In Equation 1 above,

F _{logM ≥ 5.5} is a value obtained by obtaining a molecular weight distribution curve for the ethylene / alpha-olefin copolymer through gel permeation chromatography analysis, and expressing the area of the fraction with logM ≥ 5.5 as a percentage of the total area of the molecular weight distribution curve to be.

The gel permeation chromatography analysis conditions were in accordance with Experimental Example 1 described later.

In addition, the total area of the molecular weight distribution curve and the area of the logM≧5.5 fraction can be obtained through integration, respectively.

Specifically, the ethylene/alpha-olefin copolymer satisfies Equation 1-1, Equation 1-2, Equation 1-3, or Equation 1-4 below:

[Equation 1-1]

17.1% ≤ _FlogM≥5.5

[Equation 1-2]

17.2% ≤ _FlogM≥5.5

[Equation 1-3]

17.3% ≤ _FlogM≥5.5

[Equation 1-4]

17.4% ≤ _FlogM≥5.5

In Equations 1-1 to 1-4, the definition of F _logM≥5.5 is as described above.

In addition, the ethylene/alpha-olefin copolymer satisfies Equation 2 below:

[Equation 2]

A ≤ F _logM≥5.5 ≤ B

In Equation 2, the definition of F _logM≥5.5 is as described above, A is 17%, 17.1%, 17.2%, 17.3%, or 17.4%, and B is 30%, 28%, 25%, or 22% , 20%, or 18%.

The ethylene/alpha-olefin copolymer may exhibit excellent brittle fracture resistance due to a high molecular weight ratio compared to commercially available products.

As the high molecular weight ratio increases within the above range, brittle fracture resistance increases, while resistance to ductile fracture may decrease. Accordingly, the high molecular weight ratio may be controlled in consideration of desired physical properties.

Molecular Weight Distribution (MWD)

The high molecular weight ratio (F _logM≥5.5 ) contained in the ethylene/alpha-olefin copolymer compared to commercially available products may be related to the wide molecular weight distribution.

Specifically, as a result of confirming in Experimental Example 1 described later, most commercially available products were found to have a molecular weight distribution of less than 4. When the molecular weight distribution is narrow as such, the probability that an ethylene/alpha-olefin copolymer having a relatively high molecular weight is included decreases.

On the other hand, the ethylene/alpha-olefin copolymer has a molecular weight distribution (MWD) of 10 or more, 10.5 or more, 11 or more, 11.5 or more, 12 or more, 12.5 or more, or 12.7 or more, and 30 or less, or 25 or less, or 20 or less, or less than 15, or less than 14.8, or less than 14.65, can exhibit a wide molecular weight distribution compared to most commercial products.

As the molecular weight distribution increases within the above range, the probability that an ethylene/alpha-olefin copolymer having a high molecular weight is included may increase.

For the molecular weight distribution of the ethylene/alpha-olefin copolymer, the weight average molecular weight (Mw) and the number average molecular weight (Mn) were obtained using gel permeation chromatography (GPC), respectively, and the weight average molecular weight (Mw) was determined as It can be obtained by dividing by the number average molecular weight (Mn).

More specific gel permeation chromatography analysis conditions follow Experimental Example 1 described later.

Low molecular weight fraction (F _logM≤3 )

On the other hand, resistance to ductile failure (pressure resistance characteristics) is another factor determining the long-term durability of PE-based polymer materials such as PE-RT.

Specifically, the pressure resistance performance of the PE-based polymer material is highly related to the density. The higher the density of the polymeric material, the higher the yield strength of the material and the higher the resistance to ductile fracture.

If the density is increased by increasing the crystallinity of the PE-based polymer material, the pressure resistance property is improved, but the twist and linking molecules of the chains between adjacent lamellae are reduced. This leads to a decrease in brittle fracture resistance.

Thus, the ethylene/alpha-olefin copolymer can keep its density not too high by limiting the low molecular weight ratio.

Specifically, the ethylene/alpha-olefin copolymer has a ratio of ethylene/alpha-olefin copolymer having logM≤3 of 2% or less, 1.5% or less, or 1.0% of the total ethylene/alpha-olefin copolymer (100%). % or less, 0.85% or less, or 0.82% or less.

In other words, the ethylene/alpha-olefin copolymer may satisfy Equation 1 and Equation 3 below:

[Equation 3]

_FlogM≤3 ≤ 2 %

In Equation 3 above,

F _{logM ≤ 3} is obtained by obtaining a molecular weight distribution curve for the ethylene / alpha-olefin copolymer through gel permeation chromatography analysis, a value expressed as a percentage of the area of the fraction having logM ≤ 3 relative to the total area of the molecular weight distribution curve to be.

The gel permeation chromatography analysis conditions were in accordance with Experimental Example 1 described later.

In addition, the total area of the molecular weight distribution curve and the area of the fraction having logM≤3 can be obtained through integration, respectively.

Specifically, the ethylene/alpha-olefin copolymer may satisfy Equation 3-1, Equation 3-2, Equation 3-3, Equation 3-4, or Equation 3-5 below:

[Equation 3-1]

_FlogM≤3 ≤ 3 %

[Equation 3-2]

_FlogM≤3 ≤ 1.5 %

[Equation 3-3]

_FlogM≤3 ≤ 1.0 %

[Equation 3-4]

_FlogM≤3 ≤ 0.9 %

[Equation 3-5]

F _logM ≤ 3 ≤ 0.82 %

In Equations 3-1 to 3-5, the definition of F _logM≤3 is as described above.

In addition, the ethylene/alpha-olefin copolymer satisfies Equation 4 below:

[Equation 4]

P ≤ F _logM ≤ 3 ≤ Q

In Equation 4, the definition of F _logM≤3 is as described above, P is 0%, 0.001%, 0.01%, 0.1%, 0.5%, 0.8% or 0.82%, Q is 2%, 1.8%, 1.5%, 1.3%, or 1.27%.

As the low molecular weight ratio decreases within the above range, resistance to ductile fracture increases, while resistance to brittle fracture may decrease. Accordingly, the low molecular weight ratio may be controlled in consideration of desired physical properties.

density

As described above, when the density is increased by increasing the crystallinity of the PE-based polymer material, the pressure resistance property is improved, but the twist and linking molecules of the chain between adjacent lamellae are reduced. This leads to a decrease in brittle fracture resistance.

On the other hand, when the density of the PE-based polymer material is reduced, the number of twisted and linked molecules in the chains between adjacent lamellae increases, resulting in improved brittle fracture resistance but reduced pressure resistance.

Accordingly, in the case of the ethylene/alpha-olefin copolymer, the density range measured at 23° C. according to the ASTM D1505 standard can be controlled within the range of 0.9470 to 0.9480 g/cm ³ in order to balance the pressure resistance performance and the brittle fracture resistance. .

Specifically, the ethylene / alpha-olefin copolymer has a density range of 0.9470 g / cm ³ or more, 0.9471 g / cm ³ or more, 0.9472 g / cm ³ or more, 0.9473 g / cm 3 or more, measured at 23 ° C. according to ASTM D1505 standard cm ³ or more, 0.9474 g/cm ³ or more, 0.9475 g/cm ³ or more, or 0.9476 g/cm ³ or more, and 0.9480 g/cm ³ or less, 0.9479 g/cm ³ or less, 0.9478 g/cm ³ or less, or 0.9477 g / cm ³ or less can be controlled.

Weight average molecular weight (Mw) and number average molecular weight (Mn)

The ethylene/alpha-olefin copolymer may have a weight average molecular weight (Mw) of 170,000 to 190,000 g/mol and a number average molecular weight (Mn) of 12,000 to 15,000 g/mol.

More specifically, the ethylene/alpha-olefin copolymer has a weight average molecular weight of 170,000 g/mol or greater, 173,000 g/mol or greater, 175,000 g/mol or greater, or 180,000 g/mol or greater, and 190,000 g/mol or less, 189,000 g/mol or less. g/mol or less, or 185,000 g/mol or less, and have a number average molecular weight of 12,000 g/mol or more, 12,300 g/mol or more, 12,500 g/mol or more, 12,600 g/mol or more, 13,000 g/mol or more, or 14,000 g / mol or more, and may be 15,000 g / mol or less, 14,900 g / mol or less, 14,850 g / mol or less, 14,800 g / mol or less.

The weight average molecular weight (Mw) and number average molecular weight (Mn) of the ethylene/alpha-olefin copolymer can be obtained using gel permeation chromatography, and more specific gel permeation chromatography analysis conditions are described in Experimental Example 1 to be described later. follow

Melt index (MI _2.16 and MI _21.6 )

The ethylene/alpha-olefin copolymer may have a melt index MI _2.16 of 0.08 to 0.20 g/10min. In addition, the ethylene/alpha-olefin copolymer may have a melt index MI _21.6 of 10 to 14 g/10min.

In the present specification, the melt index can be measured under a load of 2.16 kg and 21.6 kg at 230 ° C., respectively, according to ASTM D 1238, American society for testing and materials (ASTM) standard, and the polymer is melted for 10 minutes. is expressed in weight (g). Here, the melt index MI _2.16 when measured with a load of 2.16 kg, and the melt index MI _21.6 when measured with a load of 21.6 kg.

In general, the melt index of PE-based polymer materials affects dimensional stability and processability.

When the melt index MI _2.16 is less than 0.08 g/10 min or the melt index MI _21.6 is less than 10 g/10 min, the pressure during processing of the ethylene/alpha-olefin copolymer may increase and processability may deteriorate.

On the other hand, when the melt index MI _2.16 exceeds 0.20 g/10 min or the melt index MI _21.6 exceeds 14 g/10 min, the fluidity of the ethylene/alpha-olefin copolymer may increase and the dimensional stability may deteriorate.

More specifically, the ethylene / alpha-olefin copolymer has a melt index MI _2.16 of 0.08 g / 10 min or more, 0.1 g / 10 min or more, 0.11 g / 10 min or more, or 0.12 g / 10 min or more, 0.20 g / 10 min or less, It may be 0.18 g/10 min or less, 0.17 g/10 min or less, or 0.16 g/10 min or less. In addition, the ethylene / alpha-olefin copolymer has a melt index MI _21.6 of 10 g / 10 min or more, 10.5 g / 10 min or more, 11 g / 10 min or more, or 12 g / 10 min or more, 14 g / 10 min or less, 13.8 g /10 min or less, 13.6 g/10 min or less, or 13.5 g/10 min or less.

In general, the melt index can be controlled by controlling the amount of hydrogen input during the polymerization process, and the amount of hydrogen input is determined according to the hydrogen reactivity of the catalyst used.

In the present invention, the melt index of the ethylene/alpha-olefin copolymer is reduced by using a transition metal compound having low hydrogen reactivity during the preparation of the ethylene/alpha-olefin copolymer, and as a result, the viscosity in the processing area is reduced. can improve dimensional stability.

In addition, the ethylene/alpha-olefin copolymer may exhibit a melt flow rate ratio (MFRR, MI _21.6 /MI _2.16 ) of 50 to 125.

The MFRR of the ethylene/alpha-olefin copolymer is a melt index (MI _21.6 ) value measured at 190 ° C. under a load of 21.6 kg according to ASTM 1238, and a melt index measured under a load condition of 190 ° C. at 2.16 kg according to ASTM 1238. (MI _2.16 ) is the value divided by the value.

In general, MFRR is used as a value representing the shear thinning effect, and is affected by the molecular weight distribution and melt index of the ethylene/alpha-olefin copolymer. The ethylene/alpha-olefin copolymer satisfies the high molecular weight distribution conditions as described above, and exhibits high MFRR as it has a low melt index, and as a result may exhibit excellent processability.

More specifically, the ethylene/alpha-olefin copolymer has a melt flow rate ratio of 50 or more, 60 or more, 70 or more, 75 or more, 80 or more, 82 or more, 83 or more, 83.5 or more, or 84 or more, and 125 or less, 120 or less. , 115 or less, 110 or less, 105 or less, 102 or less, or 100 or less.

comonomers (alpha-olefins)

Examples of the alpha-olefin include ethylene, alpha-olefin, and cyclic olefin, and a diene olefin monomer or a triene olefin monomer having two or more double bonds may also be polymerized.

Specific examples of the monomer include ethylene, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, and 1-dodecene. sen, 1-tetradecene, 1-hexadecene, 1-aitocene, norbornene, norbornadiene, ethylidenenorbornene, phenylnorbornene, vinylnorbornene, dicyclopentadiene, 1,4-butadiene, 1, 5-pentadiene, 1,6-hexadiene, styrene, alpha-methyl styrene, divinylbenzene, 3-chloromethyl styrene, and the like, and two or more of these monomers may be mixed and copolymerized.

When the ethylene/alpha-olefin copolymer is a copolymer of ethylene and another comonomer, the comonomer is selected from the group consisting of propylene, 1-butene, 1-hexene, 4-methyl-1-pentene and 1-octene. It may be one or more comonomers.

For example, it may be 1-hexene as in the examples described below.

Methods for preparing ethylene/alpha-olefin copolymers

In the present invention, a method for preparing the aforementioned ethylene/alpha-olefin copolymer is provided.

Specifically, the preparation method includes preparing an ethylene/alpha-olefin copolymer by polymerizing an ethylene monomer and an alpha-olefin comonomer while introducing hydrogen gas in the presence of a supported hybrid catalyst.

The hybrid supported catalyst may include a first transition metal compound including a compound represented by Formula 1 below, a second transition metal compound represented by Formula 3 below; and a carrier:

[Formula 1]

In Formula 1,

C ₁ is any one of the ligands represented by Formulas 2a to 2d;

[Formula 2a]

[Formula 2b]

[Formula 2c]

[Formula 2d]

In Formulas 2a to 2d,

R ₁ to R ₉ are the same as or different from each other, and each independently represents any one of hydrogen, a hydrocarbyl group having 1 to 30 carbon atoms, and a hydrocarbyloxy group having 1 to 30 carbon atoms;

Z is -O-, -S-, -NR ₁₀ -, or -PR ₁₁ ;

R ₁₀ and R ₁₁ are any one of hydrogen, a hydrocarbyl group having 1 to 20 carbon atoms, a hydrocarbyl (oxy)silyl group having 1 to 20 carbon atoms, and a silyl hydrocarbyl group having 1 to 20 carbon atoms;

M ₁ is Ti, Zr or Hf;

X ₁ and X ₂ are the same as or different from each other, and are each independently a halogen, a nitro group, an amido group, a phosphine group, a phosphide group, a hydrocarbyl group having 1 to 30 carbon atoms, a hydrocarbyloxy group having 1 to 30 carbon atoms, Any one of a hydrocarbyloxyhydrocarbyl group having 2 to 30 carbon atoms, -SiH ₃ , a hydrocarbyl (oxy)silyl group having 1 to 30 carbon atoms, a sulfonate group having 1 to 30 carbon atoms, and a sulfone group having 1 to 30 carbon atoms,

또는

이고, T is an alkylene group having 1 to 5 carbon atoms;

or

ego,

T ₁ is C, Si, Ge, Sn or Pb;

Y ₁ to Y ₄ are the same as or different from each other, and each independently hydrogen, a C1-30 hydrocarbyl group, a C1-30 hydrocarbyloxy group, a C2-30 hydrocarbyloxyhydrocarbyl group, -SiH ₃ , a hydrocarbyl (oxy)silyl group having 1 to 30 carbon atoms, a hydrocarbyl group having 1 to 30 carbon atoms substituted with a halogen, and -NR ₁₂ R ₁₃ any one of,

R ₁₂ and R ₁₃ are each independently hydrogen and a hydrocarbyl group having 1 to 30 carbon atoms, or linked to each other to form an aliphatic or aromatic ring;

In addition, "•" in the above formula means a bonding position with T.

[Formula 3]

[Cp ₁ (R _a ) _u ][Cp ₂ (R _b ) _v ]M ₂ X ₃ X ₄

In Formula 3,

Cp ₁ and Cp ₂ are the same as or different from each other, and are each independently any one of a cyclopentadienyl group, an indenyl group, a 4,5,6,7-tetrahydro-1-indenyl group, and a fluorenyl group,

R _a and R _b are the same as or different from each other, and are each independently hydrogen, a hydrocarbyl group having 1 to 30 carbon atoms, a hydrocarbyloxy group having 1 to 30 carbon atoms, a hydrocarbyloxyhydrocarbyl group having 2 to 30 carbon atoms, -SiH ₃ , any one of a hydrocarbyl (oxy)silyl group having 1 to 30 carbon atoms and a hydrocarbyl group having 1 to 30 carbon atoms substituted with a halogen,

M ₂ is Ti, Zr or Hf;

X ₃ and X ₄ are the same as or different from each other, and are each independently a halogen, a nitro group, an amido group, a phosphine group, a phosphide group, a hydrocarbyl group having 1 to 30 carbon atoms, a hydrocarbyloxy group having 1 to 30 carbon atoms, Any one of a hydrocarbyloxyhydrocarbyl group having 2 to 30 carbon atoms, -SiH ₃ , a hydrocarbyl (oxy)silyl group having 1 to 30 carbon atoms, a sulfonate group having 1 to 30 carbon atoms, and a sulfone group having 1 to 30 carbon atoms,

u and v are each independently an integer of 0 to 5;

First transition metal compound

The first transition metal compound represented by Chemical Formula 1 includes ligands having different structures each derived from an aromatic ring compound containing thiophene and a base compound containing a Group 15 or Group 16 atom, The ligands are crosslinked by -T- and have a structure in which M ₁ (X ₁ )(X ₂ ) exists between the ligands. Due to this structural feature, the first transition metal compound exhibits high activity during olefin polymerization with excellent support stability, and as a result, an ethylene/alpha-olefin copolymer having a high molecular weight can be prepared. In addition, the first transition metal compound has high reactivity with alpha olefin, which is a comonomer, and promotes the production of linking molecules by the comonomer, thereby increasing entanglement strength during crystal formation. Ethylene/alpha olefin copolymer prepared can exhibit excellent heat resistance stability in the long term.

Specifically, the C ₁ ligand in the structure of the first transition metal compound represented by Chemical Formula 1 may affect, for example, olefin polymerization activity and alpha olefin copolymerization characteristics.

In particular, as a C ₁ ligand, R ₁ to R ₄ , R ₈ and R ₉ in Formulas 2a to 2d are each independently hydrogen or a hydrocarbyl group having 1 to 10 carbon atoms, and R ₅ to R ₇ are each independently The first transition metal compound of Chemical Formula 1 including a ligand having any one of a hydrocarbyl group having 1 to 10 carbon atoms exhibits very high activity and high comonomer conversion in an olefin polymerization process. More specifically, in the C ₁ ligand, R ₁ to R ₄ , R ₈ and R ₉ of Formulas 2a to 2d are each independently hydrogen or alkyl having 1 to 10 carbon atoms, and R ₅ to R ₇ are each independently An alkyl ligand having 1 to 10 carbon atoms, more specifically, a ligand in which R ₁ to R ₄ , R ₈ and R ₉ are each independently hydrogen or methyl, and R ₅ to R ₇ are each methyl.

In addition, the Z ligand in the structure of the first transition metal compound represented by Formula 1 may affect, for example, olefin polymerization activity.

In particular, when Z in Formula 1 is -NR ₁₀ -, and R ₁₀ is any one of a hydrocarbyl group having 1 to 10 carbon atoms, more specifically, when it is an alkyl having 1 to 10 carbon atoms, more specifically, t - In the case of C _3-6 branched alkyl such as butyl, a catalyst exhibiting very high activity in an olefin polymerization process can be provided.

의 구조를 갖고, 여기서 T₁은 C 또는 Si이고, Y₁은 탄소수 1 내지 30의 하이드로카빌기 및 탄소수 1 내지 30의 하이드로카빌옥시기 중 어느 하나이고, Y₂는 탄소수 2 내지 30의 하이드로카빌옥시하이드로카빌기 중 어느 하나일 수 있다. 구체적으로, T₁은 Si이고, Y₁은 탄소수 1 내지 20, 또는 탄소수 1 내지 10의 알킬이고, Y₂은 탄소수 2 내지 20, 또는 탄소수 2 내지 10의 알콕시알킬이거나, 탄소수 7 내지 20, 또는 탄소수 7 내지 14의 아릴옥시알킬기일 수 있다. 보다 구체적으로, T₁은 Si이고, Y₁은 메틸기, 에틸기, n-프로필기 및 n-부틸기 중 어느 하나이며, Y₂는 메톡시메틸기, 메톡시에틸기, 에톡시메틸기, iso-프로폭시메틸기, iso-프로폭시에틸기, iso-프로폭시헥실기, tert-부톡시메틸기, tert-부톡시에틸기, tert-부톡시헥실기 및 페녹시헥실기 중 어느 하나일 수 있다.In addition, the ligand of C ₁ and the ligand of Z can be crosslinked by -T- to exhibit excellent loading stability. In addition, in order to enhance this effect, the -T-

Has a structure of, where T ₁ is C or Si, and Y ₁ has 1 to 30 carbon atoms. Hydrocarbyl group and 1 to 30 carbon atoms Any one of a hydrocarbyloxy group, and Y ₂ is a carbon number of 2 to 30 It may be any one of hydrocarbyloxyhydrocarbyl groups. Specifically, T ₁ is Si, Y ₁ is C 1 to C 20 or C 1 to C 10 alkyl, Y ₂ is C 2 to C 20 or C 2 to C 10 alkoxyalkyl, C 7 to C 20, or It may be an aryloxyalkyl group having 7 to 14 carbon atoms. More specifically, T ₁ is Si, Y ₁ is any one of a methyl group, an ethyl group, an n-propyl group and an n-butyl group, and Y ₂ is a methoxymethyl group, a methoxyethyl group, an ethoxymethyl group, iso-propoxy It may be any one of a methyl group, an iso-propoxyethyl group, an iso-propoxyhexyl group, a tert-butoxymethyl group, a tert-butoxyethyl group, a tert-butoxyhexyl group, and a phenoxyhexyl group.

On the other hand, M ₁ (X ₁ ) (X ₂ ) exists between the bridged C ₁ ligand and Z ligand, and M ₁ (X ₁ ) (X ₂ ) may affect the storage stability of the metal complex. .

In order to ensure these effects more effectively, a transition metal compound in which X ₁ and X ₂ are each independently any one of halogen, more specifically, chloro may be used.

As an example, compounds represented by the following Chemical Formulas 4 to 7 may be exemplified as a first transition metal compound that exhibits superior activity during olefin polymerization and provides a high molecular weight ethylene/alpha-olefin copolymer.

[Formula 4]

[Formula 5]

[Formula 6]

[Formula 7]

In Chemical Formulas 4 to 7, R ₁ to R ₁₀ , M ₁ , X ₁ , X ₂ , T ₁ , Y ₁ and Y ₂ are as defined above.

Specifically, in Chemical Formulas 4 to 7, R ₁ to R ₄ , R ₈ and R ₉ are the same as or different from each other, and are each independently hydrogen or a hydrocarbyl group having 1 to 10 carbon atoms, and more specifically, each independently is hydrogen or alkyl having 1 to 10 carbon atoms, more specifically hydrogen or methyl each independently,

R ₅ to R ₇ are the same as or different from each other, and each independently represents any one of a hydrocarbyl group having 1 to 10 carbon atoms, more specifically, each independently represents any one of alkyl groups having 1 to 10 carbon atoms, and more specifically R ₅ to R ₇ are each methyl;

M ₁ is Ti, Zr or Hf, more specifically Ti;

X ₁ and X ₂ are the same as or different from each other, each independently any one of halogen, more specifically, each independently chloro;

T ₁ is C or Si, more specifically Si;

Y ₁ has 1 to 30 carbon atoms Hydrocarbyl group and 1 to 30 carbon atoms Any one of a hydrocarbyloxy group, and Y ₂ is a carbon number of 2 to 30 Any one of hydrocarbyloxyhydrocarbyl groups, more specifically, Y ₁ is an alkyl having 1 to 20 carbon atoms or 1 to 10 carbon atoms, Y ₂ is an alkoxyalkyl having 2 to 20 carbon atoms or 2 to 10 carbon atoms, An aryloxyalkyl group having 7 to 20 carbon atoms or 7 to 14 carbon atoms, more specifically, Y ₁ is any one of a methyl group, an ethyl group, an n-propyl group and an n-butyl group, and Y ₂ is a methoxymethyl group, Among the oxyethyl group, ethoxymethyl group, iso-propoxymethyl group, iso-propoxyethyl group, iso-propoxyhexyl group, tert-butoxymethyl group, tert-butoxyethyl group, tert-butoxyhexyl group and phenoxyhexyl group which one

More specifically, the compound represented by Chemical Formula 3 may have the following structure:

The first transition metal compound represented by Formula 1 may be synthesized by applying known reactions, and a more detailed synthesis method may refer to Examples.

Second transition metal compound

Unlike the first transition metal compound, when the second transition metal compound represented by Chemical Formula 3 is activated by an appropriate method and used as a catalyst for olefin polymerization, a low molecular weight ethylene/alpha-olefin copolymer can be provided. have. Thus, the hybrid supported catalyst comprising the first and second transition metal compounds can provide an ethylene/alpha-olefin copolymer having a broad molecular weight distribution.

Specifically, Cp ₁ and Cp ₂ in Chemical Formula 3 may be a cyclopentadienyl group. The second transition metal compound in which Cp ₁ and Cp ₂ are cyclopentadienyl groups and the cyclopentadienyl groups are not bridged shows low copolymerizability for alpha-olefins during olefin polymerization, and has a low molecular weight. Ethylene/alpha-olefin copolymers are predominantly produced. Therefore, when such a second transition metal compound is mixed-supported on the same carrier as the first transition metal compound of Formula 1, the molecular weight distribution of the ethylene/alpha-olefin copolymer, the monomers copolymerized in the ethylene/alpha-olefin copolymer chain, By easily controlling the distribution of and copolymerization characteristics of olefins, the desired physical properties of the ethylene/alpha-olefin copolymer can be more easily implemented.

The Cp ₁ may be substituted by 1 to 5 R _a , and the Cp ₂ may be substituted by 1 to 5 R _b . In Chemical Formula 3, when u is an integer of 2 or more, a plurality of R _a 's may be the same as or different from each other. In addition, when v is an integer of 2 or more in Formula 3, a plurality of R _bs may be the same as or different from each other.

Each of R _a and R _b may independently be hydrogen, a hydrocarbyl group having 1 to 10 carbon atoms, a hydrocarbyloxy group having 1 to 10 carbon atoms, and a hydrocarbyloxyhydrocarbyl group having 2 to 20 carbon atoms. More specifically, R _a and R _b are each independently hydrogen, C _1-6 straight chain or branched alkyl, C _1-6 alkoxy-substituted C _1-6 alkyl, C _6-12 aryl substituted may be C _1-6 alkyl or C _6-12 aryl. For example, R _a and R _b are each independently hydrogen, methyl (Me), ethyl (Et), n-propyl (n-Pr), iso-propyl (i-Pr), n-butyl (n-Bu ), tert-butyl (t-Bu), n-pentyl (n-Pt), n-hexyl (n-Hex), tert-butoxy (t-Bu-O) hexyl, phenylhexyl, or phenyl (Ph) can be Among them, R _a and R _b may each independently be a C _1-6 straight chain alkyl such as n-butyl. The second transition metal compound in which R _a and R _b have substituents as described above may have excellent supporting stability.

In Formula 3, M ₂ may be Zr or Hf, more specifically Zr.

In addition, X ₃ and X ₄ in Formula 3 are the same as or different from each other, and each independently may be any one of halogen, and more specifically, chloro. In the second transition metal compound in which X ₃ and X ₄ have substituents as described above, a halogen group may be easily substituted with an alkyl group by a reaction with an alkyl metal or methylaluminoxane as a cocatalyst. In addition, by the subsequent alkyl abstraction, the second transition metal compound forms an ionic intermediate with the cocatalyst, thereby more easily providing a cationic form, which is an active species of olefin polymerization reaction. have.

As an example, as a second transition metal compound for providing an ethylene/alpha-olefin copolymer having a wide molecular weight distribution in combination with the first transition metal compound, the following compounds may be exemplified.

.

.

The second transition metal compound represented by the above structural formulas may be synthesized by applying known reactions, and a more detailed synthesis method may refer to the Examples.

Meanwhile, in the present invention, each of the first and second transition metal compounds may be a meso isomer, a racemic isomer, or a mixed form thereof.

In the present specification, "racemic form" or "racemic form" or "racemic isomer" means that the same substituent on two cyclopentadienyl moieties is represented by M ₁ to M ₂ in Formulas 1 and 2 above. It means a form on the opposite side to the center of the cyclopentadienyl moiety and a plane containing a transition metal such as zirconium (Zr) or hafnium (Hf) to be displayed.

And, in the present specification, the term "meso isomer" or "meso isomer" is a stereoisomer of the aforementioned racemic isomer, wherein the same substituent on two cyclopentadienyl moieties is M in Formulas 1 to 3 A transition metal represented by ¹ to M ³ , eg, a plane containing a transition metal such as zirconium (Zr) or hafnium (Hf) and the center of the cyclopentadienyl moiety are on the same side.

The first and second transition metal compounds may be combined in an appropriate amount according to physical properties of the ethylene/alpha-olefin copolymer to be prepared. For example, to provide an ethylene/alpha-olefin copolymer with a broad molecular weight distribution and high molecular weight, the first and second transition metal compounds may be used in a molar ratio of 1:0.5 to 1:1.2.

Accordingly, the molecular weight distribution of the ethylene/alpha-olefin copolymer, the distribution of copolymerized monomers in the polymer chain, and the copolymerization characteristics of olefins can be easily controlled to more easily implement desired physical properties. More specifically, the first and second transition metal compounds may be mixed in a molar ratio of 1:0.5 to 1:1, or 1:0.5 to 1:0.7.

carrier

As the carrier, a carrier containing a hydroxy group or a siloxane group on the surface may be used. Specifically, as the carrier, a carrier containing a highly reactive hydroxy group or siloxane group may be used by removing moisture from the surface by drying at a high temperature. More specifically, as the carrier, silica, alumina, magnesia, or mixtures thereof may be used. The carrier may be dried at a high temperature, and may typically contain oxides, carbonates, sulfates, nitrates, such as Na ₂ O, K ₂ CO ₃ , BaSO ₄ and Mg(NO ₃ ) ₂ .

Meanwhile, the first and second transition metal compounds may be used in a supported catalyst state supported on a silica carrier.

When used in a supported catalyst state, the particle shape and bulk density of the prepared polymer are excellent, and can be suitably used in conventional slurry polymerization, bulk polymerization, or gas phase polymerization processes. In addition, among various carriers, since the functional group of the transition metal compound is chemically bonded and supported on the silica carrier, there is almost no catalyst released from the carrier surface in the ethylene polymerization process, and as a result, polyethylene is produced by slurry or gas phase polymerization When doing this, it is possible to minimize the fouling of the walls of the reactor or the polymer particles sticking together.

The silica carrier may have an average particle diameter (D50) of 20 to 40 μm. When having the above particle size, the transition metal compound can be supported with better efficiency, and as a result, the catalytic activity can be increased. More specifically, it may be 20 μm or more, or 25 μm or more, and 40 μm or less, or 30 μm or less.

Meanwhile, in the present invention, the average particle diameter (D50) of the silica carrier means the particle diameter at the 50% point of the cumulative distribution of the number of particles according to the particle size (particle diameter). The D50 can be measured using a laser diffraction method. Specifically, after dispersing the silica carrier to be measured in a dispersion medium such as deionized water, a commercially available laser diffraction particle size measuring device (eg Microtrac S3500) to calculate the particle size distribution by measuring the diffraction pattern difference according to the particle size when the particles pass through the laser beam. The particle size at the point where it becomes 50% of the cumulative distribution of the number of particles according to the particle size in the measuring device is calculated, and this is taken as the average particle size.

In addition, when supported on the silica carrier, the content range of the first and second transition metal compounds is 0.04 mmol or more, or 0.05 mmol or more, and 0.5 mmol or less, or 0.3 mmol or less, or 0.1 mmol or less based on 10 g of silica. can be supported by When supported in the above content range, appropriate supported catalyst activity may be exhibited, which may be advantageous in terms of maintaining the activity of the catalyst and economic efficiency.

co-catalyst

The hybrid supported catalyst may further include a cocatalyst to activate transition metal compounds that are catalyst precursors. As the cocatalyst, those commonly used in the technical field to which the present invention pertains may be applied without particular limitation. As a non-limiting example, the cocatalyst may be one or more compounds selected from the group consisting of compounds represented by Formulas 8 to 10 below.

[Formula 8]

R ₂₀ -[Al(R ₂₂ )-O] _n -R ₂₁

In Formula 8, R ₂₀ , R ₂₁ and R ₂₂ are each independently hydrogen, halogen, a hydrocarbyl group having 1 to 20 carbon atoms, or a hydrocarbyl group having 1 to 20 carbon atoms substituted with a halogen, and

n is an integer greater than or equal to 2;

[Formula 9]

D(R ₂₃ ) ₃

In Formula 9,

D is aluminum or boron;

R ₂₃ is each independently any one of a halogen, a C1-C20 hydrocarbyl group, a C1-C20 hydrocarbyloxy group, and a halogen-substituted C1-C20 hydrocarbyl group;

[Formula 10]

[LH] ⁺ [W(A) ₄ ] ^- or [L] ⁺ [W(A) ₄ ] ^-

In Formula 10,

L is a neutral or cationic Lewis base, H is a hydrogen atom,

W is a Group 13 element, A is independently a hydrocarbyl group having 1 to 20 carbon atoms; Hydrocarbyloxy group having 1 to 20 carbon atoms; and substituents in which one or more hydrogen atoms of these substituents are substituted with one or more substituents selected from halogen, a C1-C20 hydrocarbyloxy group, and a C1-C20 hydrocarbyl(oxy)silyl group.

Non-limiting examples of the compound represented by Formula 8 above include methyl aluminoxane, ethyl aluminoxane, iso-butyl aluminoxane, or tert-butyl aluminoxane. And, non-limiting examples of the compound represented by Formula 9 are trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, dimethylchloroaluminum, triisopropylaluminum, tri-sec-butylaluminum, Tricyclopentyl aluminum, tripentyl aluminum, triisopentyl aluminum, trihexyl aluminum, trioctyl aluminum, ethyldimethyl aluminum, methyl diethyl aluminum, triphenyl aluminum, tri-p-tolyl aluminum, dimethyl aluminum methoxide or dimethyl aluminum Toxide etc. are mentioned. Finally, non-limiting examples of the compound represented by Formula 10 include trimethylammonium tetrakis (pentafluorophenyl) borate, triethylammonium tetrakis (pentafluorophenyl) borate, N, N-dimethylanilinium tetrakis ( Pentafluorophenyl)borate, N,N-dimethylanilinium n-butyltris(pentafluorophenyl)borate, N,N-dimethylanilinium benzyltris(pentafluorophenyl)borate, N,N-dimethylanilinium Tetrakis(4-(t-butyldimethylsilyl)-2,3,5,6-tetrafluorophenyl)borate, N,N-dimethylanilinium tetrakis(4-(triisopropylsilyl)-2,3 ,5,6-tetrafluorophenyl)borate, N,N-dimethylanilinium pentafluorophenoxytris(pentafluorophenyl)borate, N,N-dimethyl-2,4,6-trimethylanilinium tetrakis (pentafluorophenyl)borate, trimethylammonium tetrakis(2,3,4,6-tetrafluorophenyl)borate, N,N-dimethylanilinium tetrakis(2,3,4,6-tetrafluorophenyl) )borate, hexadecyldimethylammonium tetrakis(pentafluorophenyl)borate, N-methyl-N-dodecylanilinium tetrakis(pentafluorophenyl)borate or methyldi(dodecyl)ammonium tetrakis(pentafluoro Phenyl) borate etc. are mentioned.

Among the above compounds, the cocatalyst may be more specifically an alkylaluminoxane-based cocatalyst such as methylaluminoxane.

The alkylaluminoxane-based cocatalyst stabilizes the first and second transition metal compounds and acts as a Lewis acid to combine functional groups introduced into bridge groups of the first and second transition metal compounds. Catalytic activity can be further enhanced by including a metal element capable of forming a bond through Lewis acid-base interaction.

In addition, the amount of the cocatalyst used may be appropriately adjusted according to the physical properties or effects of the desired catalyst and resin composition. For example, when silica is used as the carrier, the cocatalyst may be supported in an amount of 8 mol or more, or 9 mol or more, and 20 mol or less, or 15 mol or less, based on 1000 g of silica, based on the weight of the carrier.

catalyst manufacturing process

The hybrid supported catalyst may be prepared, for example, by supporting a cocatalyst on a carrier and supporting first and second transition metal compounds, which are catalyst precursors, on a carrier supporting the cocatalyst.

Specifically, in the step of supporting the cocatalyst on the carrier, the carrier and the cocatalyst dried at a high temperature may be mixed and stirred at a temperature of about 20 to 120° C. to prepare a carrier supporting the cocatalyst.

And, in the step of supporting the catalyst precursor on the carrier supporting the cocatalyst, the first transition metal compound is added to the carrier supporting the cocatalyst, stirred at a temperature of about 20 to 120 ° C, and then a second transition metal compound is added, Again, this may be stirred at a temperature of about 20 to 120 ° C. to prepare a hybrid supported catalyst.

In the step of supporting the catalyst precursor on the cocatalyst-supporting carrier, a catalyst precursor may be added to the cocatalyst-supporting carrier, stirred, and then a cocatalyst may be additionally added to prepare a hybrid supported catalyst.

The content of the carrier, the cocatalyst, the cocatalyst-supporting carrier, and the first and second transition metal compounds used for the hybrid supported catalyst may be appropriately adjusted according to the desired properties or effects of the hybrid supported catalyst.

In preparing the hybrid supported catalyst, hydrocarbon solvents such as pentane, hexane, and heptane, or aromatic solvents such as benzene and toluene may be used as the reaction solvent.

For a specific method of preparing the hybrid supported catalyst, reference may be made to the Examples described later. However, the preparation method of the supported hybrid catalyst is not limited to the content described herein, and the preparation method may additionally employ steps commonly employed in the technical field to which the present invention belongs, and the steps of the preparation method The (s) can be changed by a typically variable step (s).

polymerization

Meanwhile, according to another embodiment of the present invention, there is provided a method for preparing an ethylene/alpha-olefin copolymer comprising the step of polymerizing an ethylene monomer and an alpha-olefin comonomer in the presence of the supported hybrid catalyst.

As described above, the hybrid supported catalyst is a catalyst supported on a carrier by combining first and second transition metal compounds having a specific structure, and has a wider molecular weight distribution than polyolefin polymerized using a conventional metallocene catalyst, An ethylene/alpha-olefin copolymer having a high molecular weight is provided, exhibits higher activity during polymerization of olefin monomers, and can improve copolymerization properties of ethylene.

The input amount of the ethylene monomer and the alpha-olefin comonomer may be determined according to the physical properties of the copolymer to be prepared.

Specifically, 0.1 to 10 parts by weight of the alpha-olefin comonomer may be added based on 100 parts by weight of the ethylene monomer, and more specifically, 0.1 part by weight or more, or 0.5 part by weight of the alpha-olefin comonomer based on 100 parts by weight of the ethylene monomer. It may be added in an amount of 0.9 parts by weight or more, or 10 parts by weight or less, or 5 parts by weight or less, or 3 parts by weight or less.

Meanwhile, the polymerization reaction may be performed in the presence of hydrogen gas.

In the polymerization reaction, hydrogen gas activates the inactive site of the metallocene catalyst and causes a chain transfer reaction to control molecular weight. The first and second transition metal compounds used in the present invention have excellent hydrogen reactivity, and therefore, by adjusting the amount of hydrogen gas used during the polymerization process, an ethylene/alpha olefin copolymer having a desired level of molecular weight and melt index can be obtained. can be obtained effectively.

Specifically, in order to realize the physical properties of the ethylene/alpha-olefin copolymer as described above, the hydrogen gas may be added in an amount of 120 ppm to 1000 ppm based on the total weight of the monomers, that is, the ethylene monomer and the alpha-olefin comonomer. have. More specifically, the hydrogen gas may be introduced in an amount of 120 ppm or more, 150 ppm or more, or 170 ppm or more, and 1000 ppm or less, or 900 ppm or less, based on the total weight of the ethylene monomer and the alpha-olefin comonomer.

For the polymerization reaction, various polymerization processes known as polymerization of olefin monomers such as a continuous solution polymerization process, a bulk polymerization process, a suspension polymerization process, a slurry polymerization process, or an emulsion polymerization process may be employed. For example, a continuous solution polymerization process may be employed as in the examples described below.

In addition, the polymerization reaction may be carried out at a temperature of 85 °C or higher, or 90 °C or higher, and 100 °C or lower, or 95 °C or lower. In addition, the polymerization reaction may be carried out under pressure conditions of 1 kgf/cm ² or more, or 20 kgf/cm ² or more, and 100 kgf/cm ² or less, or 50 kgf/cm ² or less. Polymerization proceeds under such temperature and pressure, and the desired ethylene/alpha-olefin copolymer can be produced in high yield.

In addition, in the polymerization reaction, the hybrid supported catalyst may be used in a dissolved or diluted state in a solvent such as pentane, hexane, heptane, nonane, decane, toluene, benzene, dichloromethane, chlorobenzene, and the like. At this time, by treating the solvent with a small amount of alkylaluminum, etc., a small amount of water or air that may adversely affect the catalyst may be removed in advance.

The ethylene/alpha-olefin copolymer prepared by the above method has a high molecular weight ethylene/alpha-olefin copolymer ratio, specifically, a logM≥5.5 ethylene/alpha-olefin copolymer ratio of 17% or more, which is higher than before. . In addition, it has a wide molecular weight distribution of 10 or more, and can exhibit excellent brittle fracture resistance. In addition, the ethylene / alpha-olefin copolymer has a low molecular weight ethylene / alpha-olefin copolymer ratio of logM ≤ 3, so that the brittle fracture resistance decrease due to the increase in density is compensated for, and the density can be controlled within an optimal range, As a result, it is possible to simultaneously improve brittle fracture resistance as well as pressure resistance performance.

Pellet type polyethylene resin composition

In another embodiment of the present invention, a pellet type polyethylene resin composition comprising the ethylene/alpha-olefin copolymer of the above-described embodiment is provided.

In the present invention, a pellet or pellet-type is a small particle or piece formed by extrusion of a raw material, and in the art, such as a round, flat plate, scale, polygon, rod, etc. Includes all forms classified as

In the case of a conventional powdery polyethylene resin composition, there is a problem in that the type of antioxidants is limited and the content of antioxidants varies widely for each powder, resulting in a large variation in physical properties in articles manufactured using the same.

In contrast, the polyethylene resin composition in the present invention is prepared in the form of pellets through melt extrusion after mixing of the components, so that the components including the antioxidant in the pellets are uniformly mixed, and the yarn produced as a result can also exhibit uniform physical properties. have.

On the other hand, the size of the pellet is not particularly limited to be appropriately determined depending on the use and shape, but the pellet in the present invention is defined as having an average diameter of 2 mm or more so that it can be distinguished from a powder having a small average diameter of about 1 mm. . Specifically, the pellets in the present invention may have an average diameter of 2 mm or more, or 3 mm or more, and 200 mm or less, or 100 mm or less, or 50 mm or less, or 10 mm or less, or 5 mm or less. At this time, the "diameter" is the longest distance among any straight line distances of the outer circumferential surface of the pellet, and can be measured using a video microscope or the like.

After preparing a resin composition for forming a pellet-type polyethylene resin composition using the ethylene/alpha-olefin copolymer of the above-described embodiment, the pellet-type polyethylene resin composition may be prepared by extruding the resin composition.

The resin composition for forming the pellet-type polyethylene resin composition includes the above-described ethylene/alpha-olefin copolymer, and optionally may further include an antioxidant.

Examples of the antioxidant include organometallic compounds such as calcium stearate, aluminum para-tertiary butyl benzoic acid, sodium benzoic acid, or calcium benzoic acid; or 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene or pentaerythritol tetrakis(3-(3,5-di -t-butyl-4-hydroxyphenyl) propionate) (Irganox 1010 ^® , manufactured by BASF) and the like, or hindered phenolic antioxidants, any one or a mixture of two or more of these can be used

The organometallic compound has excellent antioxidant properties, and when used in combination with the ethylene/alpha-olefin copolymer, decomposition due to oxygen or heat in the air can be effectively prevented, thereby further improving processability.

In addition, the phenol-based antioxidants are excellent in preventing decomposition due to heat compared to conventional antioxidants such as phosphorus-based antioxidants. In addition, in the conventional resin composition in the form of a powder rather than a pellet, the uniformity of the distribution of the antioxidant is reduced by adding the antioxidant to the powdered polyethylene, and the effect is reduced because it is difficult to distribute the antioxidant inside the powder. However, in the present invention, the above-mentioned phenol By using the antioxidant in combination with the above-mentioned ethylene/alpha-olefin copolymer, the antioxidant is uniformly dispersed in the pellet-type resin composition, thereby exhibiting a more excellent thermal decomposition prevention effect and improving processability.

More specifically, as the antioxidant, processability can be further improved by using a mixture of the organic metal-based compound and the phenol-based antioxidant.

In this case, the organometallic compound may be used in an amount of 0.01 to 1% by weight based on the total weight of the polyethylene resin composition, and more specifically, 0.01% by weight or more, or 0.1% by weight or more, or 0.2% by weight based on the total weight of the polyethylene resin composition. % or more, and may be used in an amount of 0.5% by weight or less, or 0.3% by weight or less.

In addition, the phenolic antioxidant may be used in an amount of 0.01 to 1% by weight based on the total weight of the polyethylene resin composition, and more specifically, 0.1% by weight or more, or 0.2% by weight or more, or 0.3% by weight or more, and 1% by weight or less, or less than 0.5%, or less than 0.45%, or less than 0.4% by weight.

In addition, the organometallic compound and the phenolic antioxidant may be mixed and used in a weight ratio of 1: 1 to 1: 2, more specifically 1: 1 or more, or 1:1.3 or more, or 1.4 or more, and may be used in a weight ratio of 1:2 or less, or 1:1.5 or less.

Processability of the pellet-type polyethylene resin composition can be further improved when used in the above content range and further in the mixing weight ratio.

In addition, the composition may further include one or more additives such as a neutralizer, a slip agent, an anti-blocking agent, a UV stabilizer, and an antistatic agent in addition to the ethylene/alpha-olefin copolymer, the organometallic compound, and the phenolic antioxidant.

The content of the additives is not particularly limited, and may be, for example, 500 ppm or more, or 700 ppm or more, and 2500 ppm or less, or 1500 ppm or less, respectively, based on the total weight of the ethylene/alpha-olefin copolymer.

Next, an extrusion process is performed on the above resin composition to prepare a pellet-type polyethylene resin composition.

The extrusion process may be performed according to a conventional method except that the pellet die temperature is controlled in the temperature range of 150 to 190 °C.

Specifically, the extrusion process may be performed using a conventional extruder. At this time, the temperature and speed of the extruder barrel are not particularly limited. For example, it may be performed at 50 to 250 °C and 100 to 1000 rpm conditions.

In addition, the pellet die temperature during the extrusion increases the viscosity by lowering the temperature of the resin in a molten state to enable pelletization. There is a risk of lowering productivity by not being sufficiently formed or by solidifying and blocking the inside of the die. In addition, when the pellet die temperature exceeds 190 ° C., the viscosity is too low and flows like a fluid, making it difficult to manufacture pellets, such as making it impossible to cut into pellets. More specifically, the pellet die temperature may be 155 °C or higher, or 160 °C or higher, and may be performed at a temperature of 180 °C or lower or 170 °C or lower.

In addition, when the pressure is further controlled together with the pellet die temperature, the pellet die pressure may be 20 bar or more, or 30 bar or more, 50 bar or less, or 35 bar or less. When the pressure is controlled within this range, the shape and physical properties of the pellet-type polyethylene resin composition can be more easily implemented.

The pellet-type polyethylene resin composition prepared by the above method includes an ethylene/alpha-olefin copolymer and optionally an antioxidant, and exhibits the above-described physical properties, thereby exhibiting excellent water pressure resistance, dimensional stability and processability. can indicate Accordingly, it is useful for manufacturing pipes, especially large-diameter pipes and PE-RT pipes.

pipe (piping)

Another embodiment of the present invention provides a pipe (piping) manufactured using the ethylene/alpha-olefin copolymer of the above-described embodiment.

Since the above-described ethylene/alpha-olefin copolymer of one embodiment exhibits excellent brittle fracture resistance while maintaining high pressure resistance, the pipe (piping) may exhibit excellent long-term durability.

The pipe (piping) may be manufactured using a composition in which an antioxidant, a pigment, etc. are optionally added in addition to the ethylene/alpha-olefin copolymer of the above-described embodiment.

Specifically, the antioxidant may include organometallic compounds such as calcium stearate, aluminum para-tertiary butyl benzoic acid, sodium benzoic acid, or calcium benzoic acid; or 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene or pentaerythritol tetrakis(3-(3,5-di -t-butyl-4-hydroxyphenyl) propionate) (Irganox 1010™, manufactured by BASF) and the like, or hindered phenolic antioxidants, any one or a mixture of two or more thereof can be used Among them, phenolic antioxidants are mainly used as antioxidants for the purpose of preventing thermal oxidation when passing through an extruder and improving long-term thermal oxidation resistance.

In addition, as a pigment for color prescription, a conventional color master batch can be used.

The ethylene/alpha-olefin copolymer of one embodiment described above can be applied to water supply pipes without crosslinking during pipe molding. Accordingly, since the ethylene-based copolymer itself is used as a raw material, there is no need for a crosslinking agent blending process, and it is economically very advantageous because it can be easily processed in a general extruder without modification of equipment and power consumption does not change.

In addition, there is no odor problem because there is no residual problem of unreacted crosslinking agents, and therefore, the pipe made using the ethylene-based copolymer of the present invention is suitable as a water supply pipe for drinking water compared to conventional chemical crosslinking or water crosslinking pipes.

Hereinafter, preferred embodiments are presented to aid understanding of the present invention. However, the following examples are only for illustrating the present invention, and the content of the present invention is not limited by the following examples.

Example 1

(1) Preparation of hybrid supported catalyst

Silica (product name: SP952, manufacturer: Grace Davison, average particle diameter (D50): 28 μm) was dehydrated and dried for about 12 hours at a temperature of 600° C. and in a vacuum state.

50 mL of toluene was put into a glass reactor, and 10 g of the dehydrated and dried silica was added thereto, and the silica was dispersed at a temperature of about 40°C. Subsequently, 61 mL of a methylaluminoxane (MAO) solution (10 wt% in toluene) was added to the reactor, and the mixture was stirred at about 200 rpm for about 12 hours while raising the temperature of the glass reactor to about 60 ° C. was manufactured.

Meanwhile, a solution of the first transition metal compound was prepared by dissolving 0.1 mmol of the first transition metal compound represented by Formula 1a in toluene.

Then, the temperature of the reactor containing the cocatalyst supporting carrier was lowered to about 40° C., and the prepared solution of the first transition metal compound was introduced into the reactor and stirred for about 2 hours.

[Formula 1a]

Then, as a second transition metal compound, 0.07 mmol of bis(n-butylcyclopentadienyl)-zirconium(IV) dichloride represented by Formula 3a (Bis(butylcyclopentadienyl)zirconium(IV) dichloride, manufacturer: LG Chem) was added to the reactor and stirred for about 2 hours.

[Formula 3a]

Thereafter, when the reaction was completed, stirring was stopped, and the toluene layer was separated and removed from the reaction product. Then, the remaining reaction product was reduced in pressure at about 40° C. to further remove toluene remaining in the reaction product to obtain a hybrid supported catalyst.

(2) Preparation of ethylene/1-hexene copolymer

In the presence of the hybrid supported catalyst of Example 1, bulk-slurry polymerization of ethylene was performed using a loop reactor.

Specifically, the input of ethylene monomer to the loop reactor was maintained at 33 kg/hr, and hydrogen gas and 1-hexene, a comonomer, were respectively injected using a pump, and the hybrid supported catalyst prepared in Preparation Example 1 was dispersed in iso-butane at 4% by weight and injected at an amount of 2ml/min. At this time, 1-hexene was added at 0.3 kg / hr, and the hydrogen gas was added in an amount of 170 ppm based on the total weight of the monomers including the ethylene and 1-hexene, and the temperature of the reactor was 93 ° C., and the output per hour was 33 kg Ethylene / 1-hexene copolymer was prepared while maintaining.

(3) Preparation of pellet type polyethylene resin composition

A resin composition was prepared by mixing the ethylene/1-hexene copolymer, calcium stearate as an organometallic compound, and Irganox 1010 ^® (manufactured by BASF) as a phenolic antioxidant. Of 100% by weight of the total weight of the resin composition, the organometallic compound was made to be about 0.25% by weight, and the phenolic antioxidant was made to be about 0.35% by weight.

The resin composition was extruded using a twin-screw extruder to prepare a pellet-type polyethylene resin composition (average pellet diameter: 4 mm). The extrusion conditions at this time are as follows.

<Extrusion conditions>

Screw speed: 150 rpm

Feed rate: 20 kg/hr

Extruder barrel temperature: sequentially adjusted from 50℃→100℃→150℃→250℃→200℃→150℃

Pellet die temperature: 160℃

Pellet die pressure: 30 bar

Examples 2 and 3

In the preparation of the ethylene/alpha olefin copolymer in Example 1, as shown in Table 1 below, the conditions for introducing ethylene and hydrogen gas and the polymerization reaction temperature were changed in the same manner as in Example 1. Thus, an ethylene/alpha olefin copolymer and a pellet type polyethylene resin composition were prepared, respectively.

Ethylene monomer dosage
(kg/hr) hydrogen input
(ppm based on total weight of ethylene monomer and alphaolefin comonomer) Polymerization reaction temperature (℃) Example 1 33 170 93 Example 2 32.9 195 93 Example 3 32.8 196 93

Comparative Example 1 DX800™ (manufactured by SK General Chemicals, pellet type) as an ethylene/1-octene copolymer prepared using a Ziegler-Natta catalyst and having a unimodal molecular weight distribution and a pipe product manufactured using the same (SK DX800 PE -RT pipe) was used.

Comparative Example 2

As an ethylene/1-hexene copolymer manufactured using a metallocene catalyst and having a unimodal molecular weight distribution, SP980™ (manufactured by LG Chem, pellet type) and pipe products manufactured using the same (LG SP980 PE-RT pipe) was used.

Comparative Example 3

An ethylene/1-hexene copolymer prepared using a Ziegler-Natta catalyst and having a bimodal molecular weight distribution. used

Comparative Example 4

XRT-70™ (TotalEnergies, pellet type) as an ethylene/1-hexene copolymer prepared using a Ziegler-Natta catalyst and having a bimodal molecular weight distribution, and pipe products manufactured using the same (XRT-70 PE-RT pipe) was used.

Experimental Example 1

The physical properties of the ethylene/alpha-olefin copolymers of Examples and Comparative Examples were evaluated in the following manner, and the evaluation results are shown in Table 2 below.

(1) Density

For each of the above ethylene/alpha-olefin copolymers, the density was measured according to the ASTM D1505 standard. Specifically, a butyl acetate solution was used as a water displacement method and the measurement was performed at room temperature (20±5° C.).

(2) molecular weight and molecular weight distribution

1) Weight average molecular weight (Mw), number average molecular weight (Mn) and molecular weight distribution (MWD, polydispersity index)

For each of the above ethylene / alpha-olefin copolymers, using a Waters PL-GPC220 instrument equipped with a Polymer Laboratories PLgel MIX-B 300 mm long column, weight average molecular weight (Mw) and number average molecular weight (Mn) under the following conditions was measured, and the molecular weight distribution (MWD, Mw/Mn) was calculated from the measured values.

- Column: Polymer Laboratories PLgel MIX-B 300mm long column

- Solvent: TCB (Trichlorobenzene)

- Flow rate: 1.0 ml/min

- Sample concentration: 10mg/10mL

- Injection amount: 200 μl

- Column temperature: 160 ℃

- Detector: Agilent High Temperature RI detector

- Standard: Polystyrene (correction with cubic function)

Specifically, the measurement temperature was 160°C, 1,2,4-trichlorobenzene was used as a solvent, and the flow rate was 1 mL/min. A sample of each of the above ethylene/alpha-olefin copolymers was prepared at a concentration of 10 mg/10 mL, and then supplied in an amount of 200 µL.

Thereafter, a molecular weight distribution curve (GPC curve) corrected by a cubic function was obtained using a polystyrene standard, and the values of Mw and Mn were evaluated using this. Here, nine types of polystyrene standards with molecular weights of 2,000 / 10,000 / 30,000 / 70,000 / 200,000 / 700,000 / 2,000,000 / 4,000,000 / 10,000,000 (g / mol) were used.

In addition, the molecular weight distribution curves for the ethylene / alpha-olefin copolymer (PE5) of Example 1 and the ethylene / alpha-olefin copolymers (PE1, PE2, PE3, PE4) of Comparative Examples 1 to 4 are shown in FIG. was

2) high molecular weight ratio (F _logM≥5.5 ) and low molecular weight ratio (F _logM≤3 )

For each of the ethylene/alpha-olefin copolymers, from the molecular weight distribution curve (GPC curve) obtained during the gel permeation chromatography analysis of 1) above, the high molecular weight ratio (F _logM≥5.5 ) and the ultra-low molecular weight ratio (F _logM≤3 ) was obtained.

Specifically, the high molecular weight ratio (F _logM≥5.5 ) is a value expressed as a percentage of the area of the fraction having logM≥5.5 out of the total area of the molecular weight distribution curve (GPC curve).

In addition, the low molecular weight ratio (F _logMw≤3 ) is a value expressed as a percentage of the area of the fraction having logM≤3 out of the total area of the molecular weight distribution curve (GPC curve).

Here, the total area of the molecular weight distribution curve (GPC curve), the area of the logM≥5.5 fraction, and the area of the logM≤3 fraction were respectively obtained through integration.

(3) Melt index (MI _2.16 and MI _21.6 )

For each of the ethylene/alpha-olefin copolymers, a load of 2.16 kg was applied at 230° C. according to ASTM D1238, and the weight (g) of the polymer melted for 10 minutes was expressed as MI _2.16 .

In addition, the weight (g) of the polymer melted for 10 minutes by applying a load of 21.6 kg at 230 ° C. according to ASTM D1238 was expressed as MI _21.6 .

comonomer density
(g/cm ³ ) Molecular Weight and Molecular Weight Distribution melt index Melt flow rate ratio
(MI _21.6 /MI _2.16 ) M _w
(kg/mol) M _n
(kg/mol) MWD
( M _w /M _n ) _FlogM≥5.5
(%) _FlogM≤3.0 (%) MI _2.16
(g/10min) MI _21.6
(g/10min) Comparative Example 1 PE1 1-C8 0.9337 137,497 37,158 3.700 9.70 0 0.65 15.59 24.0 Comparative Example 2 PE2 1-C6 0.9376 132,419 34,551 3.833 10.0 0 0.67 21.20 31.6 Comparative Example 3 PE3 1-C6 0.9346 116,707 38,790 3.009 6.50 0 0.57 10.00 17.5 Comparative Example 4 PE4 1-C6 0.9482 181,724 7,749 23.45 16.4 2.75 0.13 15.40 118.5 Example 1 PE5 1-C6 0.9476 188,421 14,841 12.70 17.4 0.82 0.16 13.43 83.9 Example 2 PE6 1-C6 0.9477 184,498 12,623 14.62 17.3 1.27 0.11 11.10 100.9 Example 3 PE7 1-C6 0.9479 175,460 14,670 11.96 17.3 1.5 0.16 13.58 84.9

As a result of the experiment, the ethylene/alpha-olefin copolymers of Examples 1 to 3 had a high molecular weight ratio (F _logM≥5.5 ) of 17% or more compared to the ethylene/alpha-olefin copolymers of Comparative Examples 1 to 4. In addition, the ethylene/alpha-olefin copolymers of Examples 1 to 3 have a density within the range of 0.9470 to 0.9480 g/cm ³ , a molecular weight distribution of 10 or more, and a low molecular weight ratio (F _logM≤3.0 ). This is as low as 2% or less.

On the other hand, none of the ethylene/alpha-olefin copolymers of Comparative Examples 1 to 4 show the high molecular weight ratio, density, molecular weight distribution, and low molecular weight of the ethylene/1-butene copolymers of Examples 1 to 3. The ratio was not satisfied at the same time.

Experimental Example 2

Pipe properties were evaluated in the following manner for the above Examples and Comparative Examples, and the evaluation results are shown in Table 3 below.

(1) Brittle fracture resistance (CRB lifetime)

Brittle fracture resistance was measured through a cracked round bar (CRB) test according to ISO 18489.

Specifically, specimens and load conditions for measuring brittle fracture resistance are shown in FIGS. 2 and 3, respectively.

More specifically, the samples of the pellet-type polyethylene resin composition according to the above examples and the pellet-type samples prepared in Comparative Example were each made into sheets having a thickness of 10 mm or more using a heating press. After that, the CRB specimen (10 mm in diameter) was processed into a round bar shape, and a sharp notch with a depth of 1 mm was prepared on the surface of the central part using a razor blade (FIG. 2).

For the CRB specimen processed as above, a fatigue test was performed at room temperature using an LTM Electro-dynamic Testing Machine (manufactured by Zwick Roell), and the cycle required for failure was evaluated.

<Fatigue test conditions>

Load wave: Sine wave.

Load ratio (R-ratio): 0.1.

Load frequency: 10Hz

For reference, an image of a fracture surface of Comparative Example 2 under a load of 8.8 MPa is shown in FIG. 4 . Since no large deformation occurred on the fracture surface, it can be seen that brittle fracture occurred.

In addition, when measuring the brittle fracture resistance, life curves according to load conditions for the CRB specimens (PE5) of Example 1 and the CRB specimens (PE1 to PE4) of Comparative Examples 1 to 4 are shown in FIG. 5 . At this time, the cycle at the time of fracture of the CRB specimen was confirmed using a crack opening displacement (COD) analyzer for the life diagram.

In addition, as a result of the brittle fracture resistance measurement, the number of cycles required for breakage is shown in FIG. 6 .

(2) Pressure resistance performance

1) Characteristic stress (C.S)

Using Instron's model Electromechanical 3382A, C.S values of the pellet-type polyethylene resin compositions of Examples 1 to 3 and pipe products of Comparative Examples 1 to 4 were measured.

Specifically, after preparing a specimen according to ASTM D638 Type A, the elongation rate is 0.005 mm/mm/s, 0.01 mm/mm/s, 0.05 mm/mm/s, and 0.1 mm/mm/s. Then, the stress-strain curve for each stretching speed was obtained. On the other hand, in the case of the pipe products of Comparative Examples 1 to 4, after punching the pipe to prepare a specimen according to the ASTM D638 Type A standard, the C.S value was measured.

For each stretching speed, the stress at the maximum point of stress was obtained as yield stress, and the stress at 100% strain was obtained as drawing stress. The slope of the yield stress for each stretching speed and the slope of the pulling stress for each stretching speed are expressed as a linear function using the obtained yield stress and withdrawal stress for each stretching speed, and the stress corresponding to the intersection of the two linear functions is the characteristic stress (Characteristic stress; C.S).

2) σ _LPL and MRS grade

Through a hydrostatic pressure test according to ISO9080, the low prediction limit (σ _LPL ) and MRS grades of the pellet-type polyethylene resin compositions of Examples 1 to 3 and the pipe products of Comparative Examples 1 to 4 were compared.

σ _LPL : For each pipe product of Comparative Examples 1 to 4, the σ _LPL values obtained through a one-year pressure certification test based on ISO 9080 at Element (formerly Exova, Bodycote) are shown in Table 3 below.

Meanwhile, for the pellet-type polyethylene resin compositions of Examples 1 to 3, the σ _LPL values obtained by substituting the CS values obtained by the above method into Equation 3 below are shown in Table 3 below. For reference, Equation 3 below corresponds to an empirical relationship between the CS value and the σ _LPL value, and the σ _LPL value can be predicted by substituting the CS value. That is, the σLPL value obtained through Equation 3 below corresponds to the 'predicted value'.

[Equation 3]

σ _LPL =0.4 x CS + 4.55

MRS grade: The Low Prediction Limit (σ _LPL ) is calculated by extrapolating the stress-life curve up to 50 years, and based on this, the Minimum Required Strength (MRS), the pressure resistance performance grade of the material, is assigned. For example, as a result of the pressure test, if σ _LPL is 10 MPa or more, MRS10 class is given, but if 8 MPa ≤ σ _LPL < 10 MPa, it is MRS8 class.

In addition, the evaluation results of σ _LPL and MRS grade for the pellet type polyethylene resin composition (PE5) of Example 1 and the pipe products (PE1, PE2, PE3, and PE4) of Comparative Examples 1 to 4 are shown in FIG. was In addition, a graph with each brittle fracture resistance as the x-axis and MRS grade as the y-axis is shown in FIG. 8 .

comonomer brittle fracture
resistance pressure resistance CRB lifetime
(cycles) CS ^*
(MPa) σ _LPL
(MPa) MRS
grade Comparative Example 1 PE1 1-C8 237000 9.54 8.57 8 Comparative Example 2 PE2 1-C6 381000 9.78 8.70 8 Comparative Example 3 PE3 1-C6 122000 12.54 9.53 8 Comparative Example 4 PE4 1-C6 318000 14.16 10.20 10 Example 1 PE5 1-C6 421000 14.26 10.26** 10 Example 2 PE6 1-C6 807000 14.75 10.45** 10 Example 3 PE7 1-C6 603000 13.80 10.07** 10

* CRB lifecycles at Δ K _I =0.65 MPa mm ^0.5 ** Pressure resistance performance (σ _LPL ) of Example 1 is a value predicted through CS evaluation

As a result of the experiment, the pipes manufactured using the pellet-type polyethylene resin compositions of Examples 1 to 3 were excellent in both brittle fracture resistance and pressure resistance performance compared to the pipes of Comparative Examples 1 to 4.

Looking at the above experimental results, it can be seen that the pipes of Examples 1 to 3 have excellent brittle fracture resistance due to the ethylene/1-hexene copolymer having a high molecular weight (logM≥5.5) ratio of 17%. can

Specifically, the ethylene/1-hexene copolymers of Examples 1 to 3 had a molecular weight distribution (MWD) as high as 10 or more, and a high molecular weight ratio (F _logM≥5.5 ) of them as high as 17%, and thus in the form of pellets. Excellent brittle fracture resistance can be expressed.

At the same time, the ethylene/1-hexene copolymers of Examples 1 to 3 have a low molecular weight ratio (F _logM≤3.0 ) of 2% or less, maintain a density not too high, and exhibit brittle fracture resistance on pellets. reduction can be limited.

In addition, the ethylene/1-hexene copolymers of Examples 1 to 3 have a density in the range of 0.9470 to 0.9480 g/cm ³ , which corresponds to a range in which pressure resistance performance and brittle fracture resistance can be harmonized.

On the other hand, none of the ethylene/alpha-olefin copolymers of Comparative Examples 1 to 4 have the high molecular weight ratio, density, molecular weight distribution, and low molecular weight ratio of the ethylene/1-butene copolymer of Example 1. At the same time, due to an unsatisfactory relationship, the brittle fracture resistance and pressure resistance performance did not surpass the pipe of Example 1 above.

Claims (17)

An ethylene/alpha-olefin copolymer that satisfies Equation 1 below:
[Equation 1]
17% ≤ _FlogM≥5.5
In Equation 1, F _logM≥5.5 is the molecular weight distribution curve for the ethylene/alpha-olefin copolymer obtained through gel permeation chromatography analysis, and of the fraction with logMw≥5.5 for the entire area of the molecular weight distribution curve It is a value expressed as a percentage of area.
According to claim 1,
The ethylene / alpha-olefin copolymer has a molecular weight distribution of 10 or more, ethylene / alpha-olefin copolymer.
According to claim 1,
An ethylene/alpha-olefin copolymer, wherein the ethylene/alpha-olefin copolymer further satisfies Equation 3 below:
[Equation 3]
_FlogM≤3 ≤ 2 %
In Equation 3, F _logM≤3 is the molecular weight distribution curve for the ethylene/alpha-olefin copolymer obtained through gel permeation chromatography analysis, and of the fraction with logM≤3 for the entire area of the molecular weight distribution curve It is a value expressed as a percentage of area.
According to claim 1,
The ethylene / alpha-olefin copolymer has a density of 0.9470 to 0.9480 g / cm ³ measured at 23 ° C according to ASTM D1505 standard, ethylene / alpha-olefin copolymer.
According to claim 1,
The ethylene / alpha-olefin copolymer has a melt index MI _2.16 of 0.08 to 0.20 g / 10min, measured at 230 ° C. under a load of 2.16 kg according to ASTM D1238, ethylene / alpha-olefin copolymer.
According to claim 1,
The ethylene / alpha-olefin copolymer has a melt index MI _21.6 of 10 to 14 g / 10min measured at 230 ° C. under a load of 21.6 kg according to ASTM D1238, ethylene / alpha-olefin copolymer.
According to claim 1,
The ethylene / alpha-olefin copolymer has a melt flow rate ratio (MFRR, MI _21.6 / MI _2.16 ) of 50 to 125, ethylene / alpha-olefin copolymer.
According to claim 1,
The alpha-olefin is 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1- At least one selected from the group consisting of octadecene and 1-eicosene, ethylene / alpha-olefin copolymer.
Preparing an ethylene/alpha-olefin copolymer by polymerizing an ethylene monomer and an alpha-olefin comonomer while introducing hydrogen gas in the presence of a supported hybrid catalyst;
The hybrid supported catalyst may include a first transition metal compound represented by Formula 1, a second transition metal compound represented by Formula 3; and a carrier,
The hydrogen gas is introduced in an amount of 120 ppm to 1000 ppm based on the total weight of the ethylene monomer and the alpha-olefin comonomer.
Process for preparing the ethylene/alpha-olefin copolymer according to claim 1:
[Formula 1]

In Formula 1,
C ₁ is any one of the ligands represented by Formulas 2a to 2d;
[Formula 2a]

[Formula 2b]

[Formula 2c]

[Formula 2d]

In Formulas 2a to 2d,
R ₁ to R ₉ are the same as or different from each other, and each independently represents any one of hydrogen, a hydrocarbyl group having 1 to 30 carbon atoms, and a hydrocarbyloxy group having 1 to 30 carbon atoms;
Z is -O-, -S-, -NR ₁₀ -, or -PR ₁₁ ;
R ₁₀ and R ₁₁ are any one of hydrogen, a hydrocarbyl group having 1 to 20 carbon atoms, a hydrocarbyl (oxy)silyl group having 1 to 20 carbon atoms, and a silyl hydrocarbyl group having 1 to 20 carbon atoms;
M ₁ is Ti, Zr or Hf;
X ₁ and X ₂ are the same as or different from each other, and are each independently a halogen, a nitro group, an amido group, a phosphine group, a phosphide group, a hydrocarbyl group having 1 to 30 carbon atoms, a hydrocarbyloxy group having 1 to 30 carbon atoms, Any one of a hydrocarbyloxyhydrocarbyl group having 2 to 30 carbon atoms, -SiH ₃ , a hydrocarbyl (oxy)silyl group having 1 to 30 carbon atoms, a sulfonate group having 1 to 30 carbon atoms, and a sulfone group having 1 to 30 carbon atoms,
T is an alkylene group having 1 to 5 carbon atoms;

or

ego,
T ₁ is C, Si, Ge, Sn or Pb;
Y ₁ to Y ₄ are the same as or different from each other, and each independently hydrogen, a C1-30 hydrocarbyl group, a C1-30 hydrocarbyloxy group, a C2-30 hydrocarbyloxyhydrocarbyl group, -SiH ₃ , a hydrocarbyl (oxy)silyl group having 1 to 30 carbon atoms, a hydrocarbyl group having 1 to 30 carbon atoms substituted with a halogen, and -NR ₁₂ R ₁₃ any one of,
R ₁₂ and R ₁₃ are each independently hydrogen and a hydrocarbyl group having 1 to 30 carbon atoms, or linked to each other to form an aliphatic or aromatic ring;
In addition, "•" in the above formula means a bonding position with T.
[Formula 3]
[Cp ₁ (R _a ) _u ][Cp ₂ (R _b ) _v ]M ₂ X ₃ X ₄
In Formula 3,
Cp ₁ and Cp ₂ are the same as or different from each other, and are each independently any one of a cyclopentadienyl group, an indenyl group, a 4,5,6,7-tetrahydro-1-indenyl group, and a fluorenyl group,
R _a and R _b are the same as or different from each other, and are each independently hydrogen, a hydrocarbyl group having 1 to 30 carbon atoms, a hydrocarbyloxy group having 1 to 30 carbon atoms, a hydrocarbyloxyhydrocarbyl group having 2 to 30 carbon atoms, -SiH ₃ , any one of a hydrocarbyl (oxy)silyl group having 1 to 30 carbon atoms and a hydrocarbyl group having 1 to 30 carbon atoms substituted with a halogen,
M ₂ is Ti, Zr or Hf;
X ₃ and X ₄ are the same as or different from each other, and are each independently a halogen, a nitro group, an amido group, a phosphine group, a phosphide group, a hydrocarbyl group having 1 to 30 carbon atoms, a hydrocarbyloxy group having 1 to 30 carbon atoms, Any one of a hydrocarbyloxyhydrocarbyl group having 2 to 30 carbon atoms, -SiH ₃ , a hydrocarbyl (oxy)silyl group having 1 to 30 carbon atoms, a sulfonate group having 1 to 30 carbon atoms, and a sulfone group having 1 to 30 carbon atoms,
u and v are each independently an integer of 0 to 5;
According to claim 9,
The molar ratio of the first transition metal compound and the second transition metal compound in the hybrid supported catalyst is 1: 0.5 to 1: 1.2, the method for producing an ethylene / alpha-olefin copolymer.
According to claim 9,
The support is a method for producing an ethylene / alpha-olefin copolymer comprising silica, alumina, magnesia or a mixture thereof.
According to claim 9,
The first transition metal compound is any one of the compounds represented by Chemical Formulas 4 to 7,
Process for preparing ethylene/alpha-olefin copolymers:
[Formula 4]

[Formula 5]

[Formula 6]

[Formula 7]

In Formulas 4 to 7,
Wherein R ₁ to R ₄ , R ₈ and R ₉ are the same as or different from each other, and each independently represents any one of hydrogen and a hydrocarbyl group having 1 to 10 carbon atoms;
R ₅ to R ₇ are the same as or different from each other, and each independently represents any one of a hydrocarbyl group having 1 to 10 carbon atoms;
R ₁₀ is any one of hydrocarbyl groups having 1 to 10 carbon atoms;
M ₁ is Ti, Zr or Hf;
X ₁ and X ₂ are the same as or different from each other, and each independently represents any one of halogen,
T ₁ is C or Si;
Y ₁ has 1 to 30 carbon atoms Hydrocarbyl group and 1 to 30 carbon atoms Any one of a hydrocarbyloxy group, and Y ₂ is a carbon number of 2 to 30 It is any one of the hydrocarbyloxy hydrocarbyl groups.
According to claim 9,
In Formula 3, Cp ₁ and Cp ₂ are cyclopentadienyl groups,
Process for preparing ethylene/alpha-olefin copolymers.
According to claim 9,
In Formula 3, R _a and R _b are the same as or different from each other, and are each independently hydrogen, a hydrocarbyl group having 1 to 10 carbon atoms, a hydrocarbyloxy group having 1 to 10 carbon atoms, and a hydrocarbyloxy group having 2 to 20 carbon atoms. Including a second transition metal compound that is any one of the bil groups,
Process for preparing ethylene/alpha-olefin copolymers:
According to claim 9,
The hybrid supported catalyst,
Further comprising at least one cocatalyst selected from the group consisting of compounds represented by Formulas 8 to 10,
Process for preparing ethylene/alpha-olefin copolymers:
[Formula 8]
R ₂₀ -[Al(R ₂₂ )-O] _n -R ₂₁
In Formula 8, R ₂₀ , R ₂₁ and R ₂₂ are each independently hydrogen, halogen, a hydrocarbyl group having 1 to 20 carbon atoms, or a hydrocarbyl group having 1 to 20 carbon atoms substituted with a halogen, and
n is an integer greater than or equal to 2;
[Formula 9]
D(R ₂₃ ) ₃
In Formula 9,
D is aluminum or boron;
R ₂₃ is each independently any one of a halogen, a C1-C20 hydrocarbyl group, a C1-C20 hydrocarbyloxy group, and a halogen-substituted C1-C20 hydrocarbyl group;
[Formula 10]
[LH] ⁺ [W(A) ₄ ] ^- or [L] ⁺ [W(A) ₄ ] ^-
In Formula 13,
L is a neutral or cationic Lewis base, H is a hydrogen atom,
W is a Group 13 element, A is independently a hydrocarbyl group having 1 to 20 carbon atoms; Hydrocarbyloxy group having 1 to 20 carbon atoms; and substituents in which one or more hydrogen atoms of these substituents are substituted with one or more substituents selected from halogen, a C1-C20 hydrocarbyloxy group, and a C1-C20 hydrocarbyl(oxy)silyl group.
A pellet type polyethylene resin composition comprising the ethylene/alpha-olefin copolymer of claim 1.
A pipe made using the ethylene/alpha-olefin copolymer of claim 1.

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