Ethylene alpha-olefin copolymer, method for preparing same, resin composition

Abstract

The present invention relates to an ethylene alpha-olefin copolymer and a resin composition comprising the same, and more particularly, to an ethylene alpha-olefin copolymer, a method for preparing the same, a resin composition comprising the olefin copolymer, and a molded article comprising the olefin copolymer, the ethylene alpha-olefin copolymer comprises an ethylene structural unit and an alpha-olefin structural unit, and when thermal gradient interaction chromatography (TGIC) analysis is carried out, the ethylene alpha-olefin copolymer comprises more than two elution peaks which are different from each other in a temperature range of 250K to 430K, and the ethylene alpha-olefin copolymer comprises more than two elution peaks which are different from each other in a temperature range of 250K to 430K.

Description

Technical Field

[0001] The present invention relates to an ethylene α-olefin copolymer, a method for preparing the same, a resin composition including the copolymer, and a molded article. More specifically, the present invention relates to an ethylene α-olefin copolymer having two chain distributions to improve elongation and low-temperature impact strength, a method for preparing the same, a resin composition including the copolymer, and a molded article. Background Art

[0002] Polyolefins are widely used polymer materials. In order to improve the low-temperature physical properties and mechanical properties of such polyolefins, an ethylene α-olefin copolymer is mainly mixed and used.

[0003] It is reported that the [Me2Si(Me4C5)NiBu]TiCl2 (Constrained-Geometry Catalyst, "CGC") catalyst used in the conventional ethylene α-olefin copolymerization reaction by Dow Chemical Company has excellent copolymerizability with α-olefins having a large steric hindrance such as 1-hexene and 1-octene. The olefin polymer after polymerization not only has a narrow molecular weight distribution (MWD), but also has a single-chain structure with a constant branch distribution.

[0004] On the other hand, it is reported that since such a conventional ethylene α-olefin copolymer has a single-chain structure with a substantially uniform branch distribution, it is difficult to simultaneously satisfy the required physical properties such as compatibility with other resins, processability, strength, and impact strength.

[0005] For example, in order to improve the low-temperature physical properties by compounding an ethylene α-olefin copolymer with polypropylene, it is necessary to mix a relatively low-density ethylene α-olefin copolymer and use it. However, if a large amount of such a low-density ethylene α-olefin copolymer is mixed, there will be a problem of a decrease in the tensile strength of the composite resin.

[0006] Therefore, it is necessary to study a method for improving the low-temperature physical properties and mechanical properties of a composite resin without deteriorating physical properties such as tensile strength. Summary of the Invention

[0007] One aspect of the present invention provides an ethylene α-olefin copolymer and a method for preparing the same. The ethylene α-olefin copolymer uses a single metallocene catalyst in which an R-type and an S-type stereocompound coexist, and thus includes two chain structures having different branch contents.

[0008] Another aspect of the present invention provides a resin composition and a molded article, which include the copolymer of the present invention as described above, and thus elongation, impact strength, tensile strength, and shrinkage are improved.

[0009] One aspect of the present invention provides an ethylene α-olefin copolymer, which comprises ethylene structural units and α-olefin structural units. When subjected to Thermal Gradient Interaction Chromatography (TGIC) analysis, the ethylene α-olefin copolymer comprises two or more mutually distinct elution peaks in the temperature range of 250K to 430K.

[0010] The method for preparing the ethylene α-olefin copolymer of the present invention comprises the following steps: polymerizing ethylene with at least one olefin monomer in the presence of a main catalyst compound comprising a transition metal compound represented by the following Chemical Formula 1 and one or more cocatalysts selected from the compounds represented by the following Chemical Formula 2 to Chemical Formula 4.

[0011] [Chemical Formula 1]

[0012]

[0013] (In the above Chemical Formula 1,

[0014] M is a Group 4 transition metal,

[0015] Q 1 and Q 2 are each independently a halogen, (C1-C 20 ) alkyl, (C2-C 20 ) alkenyl, (C2-C 20 ) alkynyl, (C6-C 20 ) aryl, (C1-C 20 ) alkyl (C6-C 20 ) aryl, (C6-C 20 ) aryl (C1-C 20 ) alkyl, (C1-C 20 ) alkylamido, (C6-C 20 ) arylamido or (C1-C 20 ) alkylene,

[0016] R 1 、R 2 、R 3 、R 4 、R 5 、R 6 、R 7 、R 8 、R 9 and R 10 are each independently hydrogen; (C1-C 20 ) alkyl which may or may not include an acetal, ketal or ether group; (C2-C 20) alkenyl; (C1-C 20 )alkyl(C6-C 20 ) aryl; (C6-C 20 )Aryl (C1-C 20 ) alkyl; or (C1-C 20 ) alkylsilyl, said R 1 and the R 2 can be connected to each other to form a ring, the R 3 and the R 4 can be connected to each other to form a ring, the R 5 To the R 10 Two or more of them can be connected to form a ring.

[0017] R 11 , R 12 and R 13 are independently hydrogen; (C1-C 20 ) alkyl; (C2-C 20 ) alkenyl; (C1-C 20 )alkyl(C6-C 20 ) aryl; (C6-C 20 )Aryl (C1-C 20 ) alkyl; (C1-C 20 ) alkylsilyl; (C1-C 20 ) alkoxy; or (C6-C 20 ) aryloxy, said R 11 and the R 12 Or the R 12 and the R 13 Can be connected to form a ring.)

[0018] [Chemical formula 2]

[0019] -[Al(Ra)-O] n -

[0020] (In the above chemical formula 2,

[0021] Ra are each independently halogen; or (C1-C 20 ) hydrocarbon group,

[0022] n is an integer greater than or equal to 2),

[0023] [Chemical formula 3]

[0024] Q(Rb)3

[0025] (In the above chemical formula 3,

[0026] Q is aluminum or boron,

[0027] Rb is independently a halogen; or a (C1-C 20 ) hydrocarbon group) which is substituted or unsubstituted by a halogen,

[0028] [Chemical formula 4]

[0029] [W] + [Z(Rc)4] -

[0030] (In the above chemical formula 4,

[0031] [W] + is a cationic Lewis acid; or a cationic Lewis acid bonded with a hydrogen atom,

[0032] Z is a Group 13 element,

[0033] Rc is independently a (C6-C 20 ) aryl group substituted by one or more substituents selected from a halogen, a (C1-C 20 ) hydrocarbon group, an alkoxy group, and a phenoxy group; a (C1-C 20 ) alkyl group substituted by one or more substituents selected from a halogen, a (C1-C 20 ) hydrocarbon group, an alkoxy group, and a phenoxy group).

[0034] The transition metal compound may be a compound in which R-type and S-type stereocompounds coexist.

[0035] The polypropylene resin composition of the present invention comprises: polypropylene; and the ethylene α-olefin copolymer.

[0036] The molded article of the present invention can be prepared from the resin composition.

[0037] According to the present invention, an ethylene α-olefin copolymer having two chain structures with different comonomer contents is obtained using a single metallocene catalyst, and the copolymer has two chain structures with different short chain branch contents. According to the present invention, two polymer chains with different branch contents can be prepared within the same density range, and thus a polymer including the entire range from a low crystallinity region to a high crystallinity region can be synthesized. At this time, the high-branch-content polymer chain as an amorphous or low-crystallinity region can improve the low-temperature impact strength and tensile elongation, while the low-branch-content polymer chain can improve the tensile strength and shrinkage rate that may be reduced due to the increase in the amorphous or low-crystallinity region. Brief Description of the Drawings

[0038] Figure 1 It is a chart of the analysis results of Thermal Gradient Interaction Chromatography (TGIC) of each polymer obtained in Examples 1 to 3 and Comparative Example 1.

[0039] Figure 2 It is a chart showing the TGIC area ratio of the ethylene / 1-octene copolymer prepared in Examples 4 to 6 under the catalyst composition ratio. Detailed Description of the Invention

[0040] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. However, the embodiments of the present invention can be deformed into various other forms, and the scope of the present invention is not limited to the embodiments described below.

[0041] The term "alkyl" as used in the present invention refers to a monovalent straight-chain or branched-chain saturated hydrocarbon radical composed only of carbon and hydrogen atoms. Examples of such alkyl radicals include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, octyl, dodecyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, etc., but are not limited thereto.

[0042] In addition, the term "alkenyl" as used in the present invention refers to a straight-chain or branched-chain hydrocarbon radical containing one or more carbon-carbon double bonds, including vinyl, propenyl, butenyl, pentenyl, etc., but is not limited thereto.

[0043] In addition, the term "alkynyl" as used in the present invention refers to a straight-chain or branched-chain hydrocarbon radical containing one or more carbon-carbon triple bonds, including methynyl, ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl, octynyl, etc., but is not limited thereto.

[0044] In addition, the term "aryl" as used in the present invention refers to an organic radical derived from an aromatic hydrocarbon by removing one hydrogen atom, including a monocyclic or fused-ring system. Specific examples include phenyl, naphthyl, biphenyl, anthryl, fluorenyl, phenanthryl, triphenylenyl, pyrenyl, perylenyl, -yl, tetraphenylenyl, fluoranthenyl, etc., but are not limited thereto.

[0045] In addition, the term "alkylaryl" as used in the present invention refers to an organic group in which one or more hydrogens in the aryl are substituted by alkyl, including methylphenyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, tert-butylphenyl, etc., but is not limited thereto.

[0046] In addition, the term "arylalkyl" as described in the present invention refers to an organic group in which one or more hydrogens in an alkyl group are substituted by an aryl group, including phenylpropyl, phenylhexyl, etc., but not limited thereto.

[0047] In addition, the term "amide group" as described in the present invention refers to an amino group (-NH2) bonded to a carbonyl group (C=O), "alkylamide group" refers to an organic group in which at least one hydrogen in the -NH2 of the amide group is substituted by an alkyl group, and "arylamide group" refers to an organic group in which at least one hydrogen in the -NH2 of the amide group is substituted by an aryl group. The alkyl group in the alkylamide group and the aryl group in the arylamide group may be the same as the examples of the aforementioned alkyl group and aryl group, but not limited thereto.

[0048] In addition, the term "alkylene" as described in the present invention refers to a divalent aliphatic hydrocarbon group obtained by removing two hydrogen atoms from the same carbon atom of an alkyl group, including ethylene, propylene, isopropylidene, butylene, pentylene, etc., but not limited thereto.

[0049] In addition, the term "acetal" as described in the present invention refers to an organic group formed by the bonding of an alcohol and an aldehyde, that is, a substituent with two ether (-OR) bonds on one carbon, including methoxymethoxy, 1-methoxyethoxy, 1-methoxypropoxy, 1-methoxybutoxy, 1-ethoxyethoxy, 1-ethoxypropoxy, 1-ethoxybutoxy, 1-(n-butoxy)ethoxy, 1-(isobutoxy)ethoxy, 1-(sec-butoxy)ethoxy, 1-(tert-butoxy)ethoxy, 1-(cyclohexyloxy)ethoxy, 1-methoxy-1-methylmethoxy, 1-methoxy-1-methylethoxy, etc., but not limited thereto.

[0050] In addition, the term "ether" as described in the present invention refers to an organic group containing at least one ether bond (-O-), including 2-methoxyethyl, 2-ethoxyethyl, 2-butoxyethyl, 2-phenoxyethyl, 2-(2-methoxyethoxy)ethyl, 3-methoxypropyl, 3-butoxypropyl, 3-phenoxypropyl, 2-methoxy-1-methylethyl, 2-methoxy-2-methylethyl, 2-methoxyethyl, 2-ethoxyethyl, 2-butoxyethyl, 2-phenoxyethyl, etc., but not limited thereto.

[0051] In addition, the term "silyl" as described in the present invention refers to an -SiH3 radical derived from silane, and at least one of the hydrogen atoms in the silyl group can be substituted with various organic groups such as alkyl, halogen, etc. Specifically, it includes trimethylsilyl, triethylsilyl, tert-butyldimethylsilyl, vinyldimethylsilyl, propyldimethylsilyl, triphenylsilyl, diphenylsilyl, phenylsilyl, trimethoxysilyl, methyldimethoxysilyl, ethyldiethoxysilyl, triethoxysilyl, vinyldimethoxysilyl, triphenoxysilyl, etc., but is not limited thereto.

[0052] In addition, the term "alkoxy" as described in the present invention refers to an -O-alkyl radical, where "alkyl" is defined as above. Examples of such alkoxy radicals include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tert-butoxy, etc., but are not limited thereto.

[0053] In addition, the term "halogen" as described in the present invention refers to a fluorine, chlorine, bromine, or iodine atom.

[0054] In addition, the term "C n " in the present invention means that the number of carbon atoms is n.

[0055] The present invention aims to provide an ethylene α-olefin copolymer, which, although using a single metallocene catalyst, has two chains with different branch contents through catalyst isomers. That is, the present invention can provide an ethylene α-olefin copolymer and a composition including the copolymer, wherein the ethylene α-olefin copolymer uses a single metallocene catalyst and has two chain structures with different short chain branch contents.

[0056] In particular, the copolymer of the present invention includes two polymer chains with different branch contents within the same density range, thereby including regions from low crystallinity to high crystallinity. Among them, the high-branch-content polymer chains in the amorphous or low-crystallinity region can improve the low-temperature impact strength and tensile elongation, while the low-branch-content polymer chains can simultaneously improve the tensile strength and shrinkage rate that may be reduced due to the increase in the amorphous or low-crystallinity region.

[0057] That is, the ethylene α-olefin copolymer prepared in the present invention is an ethylene α-olefin copolymer including ethylene structural units and α-olefin structural units. When subjected to thermal gradient interaction chromatography (TGIC) analysis, it elutes at two different temperatures, so that two chain structures with different branch contents can be confirmed to be generated.

[0058] The present invention provides an ethylene α-olefin copolymer which, when analyzed by Thermal Gradient Interaction Chromatography (TGIC), includes two or more mutually distinct elution peaks in the temperature range of 250K to 430K.

[0059] More specifically, the ethylene α-olefin copolymer of the present invention has a multimodal Thermal Gradient Interaction Chromatography (TGIC) distribution. When performing TGIC analysis, the low-crystallinity region of the copolymer has a low elution temperature due to high polymer mobility, and the high-crystallinity region has a high elution temperature due to low polymer mobility. Therefore, when the low-crystallinity region and the high-crystallinity region coexist, there are two or more elution intervals. Thus, a resin composition formed by mixing the ethylene α-olefin copolymer of the present invention with a polyolefin can improve the impact strength due to the low-crystallinity region of the ethylene α-olefin copolymer. In addition, the high-crystallinity region of the ethylene α-olefin copolymer can prevent a decrease in the tensile strength caused by an increase in the low-crystallinity region in the resin composition, thereby providing a resin composition having sufficient tensile strength and impact strength.

[0060] According to one aspect of the present invention, there is provided an ethylene α-olefin copolymer which includes ethylene structural units and α-olefin structural units, wherein, when analyzed by Thermal Gradient Interaction Chromatography (TGIC), the ethylene α-olefin copolymer includes two mutually distinct elution peaks and has a first elution temperature and a second elution temperature, and the difference between the first elution temperature and the second elution temperature is 10K to 60K.

[0061] The α-olefin may be C2-C 12 or an aliphatic α-olefin of C2-C8. More specifically, propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-eicosene, 4,4-dimethyl-1-pentene, 4,4-diethyl-1-hexene, or 3,4-dimethyl-1-hexene, etc. may be mentioned, and any one or a mixture of two or more thereof may be used.

[0062] Depending on the ratio of the ethylene structural units and the α-olefin comonomer structural units present in the ethylene α-olefin copolymer, its physical properties may vary.

[0063] There is no particular limitation on the ratio of ethylene structural units to α-olefin structural units in the ethylene-α-olefin copolymer, but the weight ratio of ethylene structural units to α-olefin structural units in the ethylene-α-olefin copolymer can be from 1:0.1 to 1:1, preferably present in a weight ratio of 1:0.15 to 1:0.75.

[0064] If the content of α-olefin structural units is lower than the above range, the improvement effects of tensile elongation, low-temperature impact strength, and shrinkage rate are not obvious. If it exceeds the above range, it may cause adhesion between products, thereby reducing processability.

[0065] In the present invention, the first elution temperature can be calculated by the following formula (1):

[0066] -2.5×(α-olefin monomer content) + 132.5 Formula (1)

[0067] On the other hand, the polymer eluted at the first elution temperature satisfies the following formula:

[0068] 1) SCB = 2.5429×(α-olefin content) + 6.9429

[0069] 2) Mw = [10.151×(α-olefin content) + 198.09]×1000

[0070] The higher the α-olefin content, the lower the first elution temperature, and the mechanical properties can be improved.

[0071] On the other hand, for example, the first elution temperature can be 310K to 345K, and the second elution temperature can be 350K to 380K. At this time, the ratio of the elution amount at the first elution temperature / the elution amount at the second elution temperature can be 0.5 to 7.3, or 0.7 to 2, for example, 0.76 to 1.9.

[0072] In addition, for example, the ratio of the first elution temperature / the second elution temperature can be 0.5 to 0.91, for example, 0.55 to 0.91.

[0073] In the present invention, the polymerization of ethylene and α-olefin can be carried out under a catalyst composition including R-type and S-type of the transition metal compound represented by the following chemical formula 1.

[0074] [Chemical formula 1]

[0075]

[0076] In the above chemical formula 1,

[0077] M is a Group 4 transition metal,

[0078] Q1 and Q 2 are each independently halogen, (C1-C 20 )alkyl, (C2-C 20 )alkenyl, (C2-C 20 )alkynyl, (C6-C 20 )aryl, (C1-C 20 )alkyl(C6-C 20 )aryl, (C6-C 20 )aryl(C1-C 20 )alkyl, (C1-C 20 )alkylamido, (C6-C 20 )arylamido or (C1-C 20 )alkylene,

[0079] R 1 、R 2 、R 3 、R 4 、R 5 、R 6 、R 7 、R 8 、R 9 and R 10 are each independently hydrogen; (C1-C 20 )alkyl which may or may not include an acetal, ketal or ether group; (C2-C 20 )alkenyl which may or may not include an acetal, ketal or ether group; (C1-C 20 )alkyl(C6-C 20 )aryl which may or may not include an acetal, ketal or ether group; (C6-C 20 )aryl(C1-C 20 )alkyl which may or may not include an acetal, ketal or ether group; or (C1-C 20 )silyl which may or may not include an acetal, ketal or ether group, wherein R 1 and R 2 may be connected to each other to form a ring, and R 3 and R 4 may be connected to each other to form a ring, and two or more of R 5 to R 10 may be connected to each other to form a ring,

[0080] R 11 、R 12 and R 13 are each independently hydrogen; (C1-C 20 )alkyl which may or may not include an acetal, ketal or ether group; (C2-C 20) alkenyl; (C1-C 20 ) alkyl (C6-C 20 ) aryl; (C6-C 20 ) aryl (C1-C 20 ) alkyl; (C1-C 20 ) silyl; (C1-C 20 ) alkoxy; or (C6-C 20 ) aryloxy, wherein R 11 and R 12 may be connected to each other to form a ring, and R 12 and R 13 may be connected to each other to form a ring.

[0081] The transition metal compound represented by the above Chemical Formula 1 includes a ligand with a novel structure, and the ligand with the novel structure forms a condensed ring by an amido ligand and an o-phenylene, and the five-membered ring π-ligand bonded to the o-phenylene is fused through a thiophene heterocycle. Thus, compared with the transition metal compound not fused with a thiophene heterocycle, the transition metal compound has the advantage of high copolymerization activity of ethylene and α-olefin.

[0082] According to the present invention, in the transition metal compound represented by the above Chemical Formula 1, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 and R 13 may each independently be substituted with a substituent including an acetal, ketal or ether group. If substituted with the above-mentioned substituent, it can be more helpful to load the transition metal compound onto the surface of the carrier.

[0083] In addition, in the transition metal compound represented by the above Chemical Formula 1, M may be titanium (Ti), zirconium (Zr) or hafnium (Hf).

[0084] In addition, in the transition metal compound represented by the above Chemical Formula 1, preferably Q 1 and Q 2 are each independently halogen or (C1-C 20 ) alkyl, and more preferably may be chlorine or methyl.

[0085] In addition, in the transition metal compound represented by the above Chemical Formula 1, the R 1 , R 2 , R 3 , R 4 , and R 5 can each independently be hydrogen or a (C1-C 20 ) alkyl group, preferably each independently can be hydrogen or methyl. More preferably, the R 1 , R 2 , R 3 , R 4 , and R 5 can each independently be hydrogen or methyl, but at least one of R 3 and R 4 can be methyl, and R 5 can be methyl.

[0086] In addition, in the transition metal compound represented by the above Chemical Formula 1, preferably the R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , and R 13 are each hydrogen.

[0087] The transition metal compound represented by the above Chemical Formula 1 preferably includes the substituents as described above, which is beneficial to controlling the electronic environment and steric environment around the metal.

[0088] On the other hand, the transition metal compound represented by the above Chemical Formula 1 can be obtained from the precursor compound represented by the following Chemical Formula 5.

[0089] [Chemical Formula 5]

[0090]

[0091] In the above Chemical Formula 5, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , and R 13 are each the same as defined in the above Chemical Formula 1.

[0092] Here, the precursor compound represented by the above Chemical Formula 5 can be prepared by a method including the following steps: (i) reacting the tetrahydroquinoline derivative represented by the following Chemical Formula 6 with an alkyllithium and then adding carbon dioxide to prepare a compound represented by Chemical Formula 7; (ii) reacting the compound represented by the above Chemical Formula 7 with an alkyllithium and then adding the compound represented by the following Chemical Formula 8 and performing an acid treatment.

[0093] [Chemical Formula 6]

[0094]

[0095] [Chemical Formula 7]

[0096]

[0097] [Chemical Formula 8]

[0098]

[0099] In the above Chemical Formula 6, Chemical Formula 7, and Chemical Formula 8, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 and R 13 are respectively the same as defined in the above Chemical Formula 1.

[0100] However, in the above Chemical Formula 6, Chemical Formula 7, and Chemical Formula 8, the R 1 , R 2 , R 3 , R 4 and R 5 can be respectively independently hydrogen or (C1-C 20 ) alkyl, preferably can be respectively independently hydrogen or methyl. More preferably, the R 1 , R 2 , R 3 , R 4 and R 5 can be respectively independently hydrogen or methyl, but at least one of R 3 and R 4 can be methyl, and R 5 can be methyl. In addition, preferably the R 6 , R 7 , R 8 , R 9 , R 10, R 11 , R 12 and R 13 are hydrogen, respectively. Thereby, the proximity and reactivity of the starting materials can be ensured, and it is beneficial to control the electronic environment and steric environment of the transition metal compound of Formula 1 to be prepared.

[0101] In the preparation of the precursor compound represented by Formula 5, the step i is a reaction of reacting the tetrahydroquinoline derivative represented by the above Formula 6 with alkyllithium and then adding carbon dioxide to convert it into the compound represented by the above Formula 7, which can be carried out according to the methods described in known literature (Tetrahedron Lett. 1985, 26, 5935; Tetrahedron 1986, 42, 2571; J. Chem. SC. Perkin Trans. 1989, 16.).

[0102] In addition, in the step ii, the compound represented by the above Formula 7 can be reacted with alkyllithium to initiate a deprotonation reaction to generate an ortho-lithium compound, and then the ortho-lithium compound is reacted with the compound represented by Formula 8 and treated with an acid to obtain the transition metal compound precursor represented by the above Formula 5.

[0103] The reaction of reacting the compound represented by the above Formula 7 with alkyllithium to generate an ortho-lithium compound can be understood from known literature (Organometallics 2007, 27, 6685; Korean Patent Publication No. 2008-0065868). In the present invention, the transition metal compound precursor represented by the above Formula 5 can be obtained by reacting the ortho-lithium compound with the compound represented by the above Formula 8 and treating with an acid.

[0104] Herein, the compound represented by the above Formula 8 can be prepared by a variety of known methods. The following Reaction Scheme 1 shows an example, which can be prepared in only one step reaction, and using inexpensive starting materials, the transition metal compound precursor of the present invention can be prepared simply and economically (J. Organomet. Chem., 2005, 690, 4213).

[0105] [Reaction Scheme 1]

[0106]

[0107] On the other hand, in order to synthesize the transition metal compound represented by the above chemical formula 1 from the precursor compound represented by the above chemical formula 5 obtained by the above method, various known methods can be used. It can be prepared by the following method: Add about 2 equivalents of alkyllithium to the precursor compound represented by the above chemical formula 5 to initiate a deprotonation reaction. After preparing a dilithium compound of cyclopentadienyl anion and amide anion, add (Q 1 )(Q 2 )MCl2 thereto and remove about 2 equivalents of LiCl.

[0108] In addition, the compound represented by the above chemical formula 5 can be reacted with the M(NMe2)4 compound to remove about 2 equivalents of HNMe2 to obtain a transition metal compound represented by the above chemical formula 1 in which Q 1 and Q 2 are both NMe2 at the same time. Then, the transition metal compound is reacted with Me2SiCl or Me2SiCl2 to replace the NMe2 ligand with a chlorine ligand.

[0109] The transition metal compound represented by the chemical formula 1 prepared by the above process includes R-type and S-type. Therefore, when a polymerization reaction is carried out under a catalyst composition that simultaneously includes these structures, two polymers with different structures and physical properties can be formed.

[0110] This is considered to be due to the difference in ethylene conversion rates between the R-type and S-type. The comonomer conversion rates of the R-type and S-type are similar, but due to the difference in steric structures, they may have different ethylene conversion rates. Specifically, since the S-type has a wider space for ethylene insertion than the R-type, additional energy is required to form a specific arrangement for the polymerization reaction. Therefore, the S-type exhibits a lower ethylene conversion rate, and thus a polymer chain with a relatively high comonomer content and a thinner lamellar thickness can be formed. On the contrary, the R-type exhibits a higher ethylene conversion rate and can form a polymer chain with a relatively low comonomer content and a thicker lamellar thickness.

[0111] In this way, the transition metal compound of the present invention can produce polymers with different structures even when using a single catalyst due to the coexistence of two stereocompounds. The transition metal compound of the present invention is represented by the following structural formula and includes two compounds, namely, the S-type stereocompound (a) and the R-type stereocompound (b), and thus functions as two catalysts.

[0112]

[0113] The R-type stereocompound (b) forms a polymer chain including a low comonomer, and the S-type stereocompound (a) forms a polymer chain including a high comonomer. The reason is considered as follows: The comonomer conversion rate is similar in the R-type stereocompound (b) and the S-type stereocompound (a), but since the ethylene conversion rate of the S-type stereocompound is lower, the S-type stereocompound (a) forms a polymer chain with a relatively high comonomer content.

[0114] When the catalyst turns into an active species, the methyl group of Ti is located on the opposite side due to the steric hindrance of the sulfur (S) atom of thiophene. Subsequently, for the R-type stereocompound (b), since the space for ethylene insertion is narrow and cannot rotate, as shown in the structural formula of the insertion structure of the active species ethylene below, ethylene and the methyl group (Me) are in the same plane and are prone to polymerization by migration.

[0115]

[0116] On the other hand, as shown in the structural formula of the insertion structure of the racemic active species ethylene below for the S-type stereocompound (a), the space for ethylene insertion is wider, so ethylene rotates and coordinates with Ti, and rotational energy is required for polymerization to be in the same plane as the methyl group (Me). Therefore, the ethylene conversion rate of the S-type stereocompound (a) is lower than that of the R-type stereocompound (b).

[0117]

[0118] When the comonomer is inserted, since its molecular size is larger than that of ethylene, the S-type stereocompound is also in the same plane as the methyl group (Me) due to ligand steric hindrance, and it is considered that the comonomer conversion rate is similar to that of the R-type stereocompound (b).

[0119] To prepare an ethylene α-olefin copolymer including two polymer chains with different comonomer contents under the said catalyst composition, it is preferred that the S-type and the R-type exist in a molar ratio of 1.5:0.1 to 1:1, for example, a molar ratio of 1.1:0.1 to 1:1. If the molar ratio is lower than 1.5:0.1, a large amount of low-density polymer chains will be formed due to the predominance of the S-type, which may cause product adhesion; if the molar ratio exceeds 1:1, a large amount of high-density polymer chains will be formed, and the improvement effects of tensile elongation and low-temperature impact strength will be insufficient.

[0120] In the present invention, the catalyst composition may further include a cocatalyst compound. The cocatalyst compound is used to activate the transition metal compound, and an aluminoxane compound, an organo-aluminum compound, or a bulky compound that activates the catalyst compound may be used. Specifically, the cocatalyst compound may be selected from the compounds represented by Chemical Formula 2 to Chemical Formula 4 below.

[0121] [Chemical Formula 2]

[0122] -[Al(Ra)-O] n -

[0123] In Chemical Formula 2 above,

[0124] Ra is independently a halogen; or a (C1-C 20 ) hydrocarbon group which is substituted or unsubstituted by a halogen,

[0125] n is an integer of 2 or more.

[0126] [Chemical Formula 3]

[0127] Q(Rb)3

[0128] In Chemical Formula 3 above,

[0129] Q is aluminum or boron,

[0130] Rb is independently a halogen; or a (C1-C 20 ) hydrocarbon group which is substituted or unsubstituted by a halogen.

[0131] [Chemical Formula 4]

[0132] [W] + [Z(Rc)4] -

[0133] In Chemical Formula 4 above,

[0134] [W] + is a cationic Lewis acid; or a cationic Lewis acid bonded with a hydrogen atom,

[0135] Z is a Group 13 element,

[0136] Rc is independently an aryl group of (C6-C 20 ) which is substituted by one or more substituents selected from a halogen, a (C1-C 20 ) hydrocarbon group, an alkoxy group, and a phenoxy group; an alkyl group of (C1-C 20 ) which is substituted by one or more substituents selected from a halogen, a (C1-C 20 ) hydrocarbon group, an alkoxy group, and a phenoxy group.

[0137] The cocatalyst compound is included in the catalyst together with the transition metal compound represented by Chemical Formula 1 above, and serves to activate the transition metal compound. Specifically, in order for the transition metal compound to become an active catalyst component used in olefin polymerization, compounds including the unit represented by Chemical Formula 2 above, the compound represented by Chemical Formula 3 above, and the compound represented by Chemical Formula 4 above act together as cocatalysts. These compounds cationize the central metal (M 1 or M 2 ) by extracting the ligand in the transition metal compound, and at the same time can act as an anti-ion with a weak bonding force, that is, an anion.

[0138] The "unit" represented by Chemical Formula 2 above is a structure in which n structures within "[]" are connected in a compound. As long as the unit represented by Chemical Formula 2 is included, there is no particular limitation on other structures in the compound, and it can be a cluster type in which repeating units of Chemical Formula 2 are connected to each other, such as a spherical compound.

[0139] In order for the cocatalyst compound to exhibit a more excellent activation effect, the compound represented by Chemical Formula 2 above is not particularly limited as long as it is an alkylaluminoxane, but preferred examples may include methylaluminoxane, ethylaluminoxane, isobutylaluminoxane, butylaluminoxane, etc., and a particularly preferred compound is methylaluminoxane.

[0140] In addition, the compound represented by Chemical Formula 3 above is an alkyl metal compound, and there is no particular limitation on it. Non-limiting examples thereof include trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, dimethylchloroaluminum, triisopropylaluminum, tri-sec-butylaluminum, tricyclopentylaluminum, tripentylaluminum, triisopentylaluminum, trihexylaluminum, trioctylaluminum, ethyldimethylaluminum, methyldiethylaluminum, triphenylaluminum, tri-p-tolylaluminum, methoxydimethylaluminum, ethoxydimethylaluminum, trimethylboron, triethylboron, triisobutylboron, tripropylboron, tributylboron, etc. Considering the activity of the transition metal compound, one or more selected from trimethylaluminum, triethylaluminum, and triisobutylaluminum can be preferably used.

[0141] For the compound represented by Chemical Formula 4, when considering the activity of the transition metal compound, if the [W] + is a cationic Lewis acid bonded with a hydrogen atom, then [W] + is preferably dimethylanilinium cation; if the [W] + is a cationic Lewis acid, then [W] + is preferably [(C6H5)3C] + , and the [Z(Rc)4] - is preferably [B(C6F5)4] -。

[0142] The compound represented by Chemical Formula 4 is not particularly limited, but when [W] + Non-limiting examples of the cationic Lewis acid bonded with a hydrogen atom are preferably selected from triphenylcarbenium borate, trimethylammonium tetraphenylborate, methyldioctadecylammonium tetraphenylborate, triethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, tri(n-butyl)ammonium tetraphenylborate, methyldicyclooctadecylammonium tetraphenylborate N,N-dimethylaniline tetraphenylborate, N,N-diethylaniline tetraphenylborate, N,N-dimethyl(2,4,6-trimethylaniline) tetraphenylborate, trimethylammonium tetrakis(pentafluorophenyl)borate, methylditetradecylammonium tetrakis(pentafluorophenyl)borate, methyldioctadecylammonium tetrakis(pentafluorophenyl)borate, triethylammonium tetrakis(pentafluorophenyl)borate, tripropylammonium tetrakis(pentafluorophenyl)borate, tri(n-butyl)ammonium tetrakis(pentafluorophenyl)borate, tri(sec-butyl)ammonium tetrakis(pentafluorophenyl)borate, N,N-dimethylaniline tetrakis(pentafluorophenyl)borate, N,N-diethylaniline tetrakis(pentafluorophenyl)borate, N,N-dimethyl(2,4,6-trimethylaniline) tetrakis(pentafluorophenyl)borate, trimethylammonium tetrakis(2,3,4,6-tetrafluorophenyl)borate, triethylammonium tetrakis(2,3,4,6-tetrafluorophenyl)borate, tripropylammonium tetrakis(2,3,4,6-tetrafluorophenyl)borate, tri(n-butyl)ammonium tetrakis(2,3,4,6-tetrafluorophenyl)borate, dimethyl(tert-butyl)ammonium tetrakis(2,3,4,6-tetrafluorophenyl)borate, N,N-dimethylaniline tetrakis(2,3,4,6-tetrafluorophenyl)borate, N,N-diethylaniline tetrakis(2,3,4,6-tetrafluorophenyl)borate, N,N-dimethyl-(2,4,6-trimethylaniline) tetrakis(2,3,4,6-tetrafluorophenyl)borate, dioctadecylammonium tetrakis(pentafluorophenyl)borate, ditetradecylammonium tetrakis(pentafluorophenyl)borate, dicyclohexylammonium tetrakis(pentafluorophenyl)borate, triphenylphosphonium tetrakis(pentafluorophenyl)borate, methyldioctadecylphosphonium tetrakis(pentafluorophenyl)borate, tris(2,6-dimethylphenyl)phosphonium tetrakis(pentafluorophenyl)borate, methyldi(octadecyl)ammonium tetrakis(pentafluorophenyl)borate, methyldi(tetradecyl)ammonium tetrakis(pentafluorophenyl)borate, trityltetrakis(pentafluorophenyl)borate, and dialkylammonium, and one or more thereof.

[0143] Non-limiting examples of the dialkylammonium may include bis(isopropyl)ammonium tetrakis(pentafluorophenyl)borate or dicyclohexylammonium tetrakis(pentafluorophenyl)borate.

[0144] In addition, for the compound represented by Chemical Formula 4, when [W] +Non-limiting examples of the cationic Lewis acid are preferably one or more selected from trialkylphosphonium, dialkyloxonium, dialkylsulfonium, and carbonium salts.

[0145] Non-limiting examples of the trialkylphosphonium may include triphenylphosphonium tetrakis(pentafluorophenyl)borate, tris(o-tolylphosphonium) tetrakis(pentafluorophenyl)borate, or tris(2,6-dimethylphenyl)phosphonium tetrakis(pentafluorophenyl)borate, etc.

[0146] Non-limiting examples of the dialkyloxonium may include diphenyloxonium tetrakis(pentafluorophenyl)borate, bis(o-tolyl)oxonium tetrakis(pentafluorophenyl)borate, or bis(2,6-dimethylphenyl)oxonium tetrakis(pentafluorophenyl)borate, etc.

[0147] Non-limiting examples of the dialkylsulfonium may include diphenylsulfonium tetrakis(pentafluorophenyl)borate, bis(o-tolyl)sulfonium tetrakis(pentafluorophenyl)borate, or bis(2,6-dimethylphenyl)sulfonium tetrakis(pentafluorophenyl)borate, etc.

[0148] Non-limiting examples of the carbonium salt may include tropylium tetrakis(pentafluorophenyl)borate, triphenylmethyl carbonium tetrakis(pentafluorophenyl)borate, or benzene(diazonium) tetrakis(pentafluorophenyl)borate, etc.

[0149] The compounds of Formula 1 to Formula 4 above can be used to prepare the catalyst, and at this time, the catalyst preparation method can adopt the methods exemplified below.

[0150] As the first method, there is a method of contacting the transition metal compound with the compound represented by Formula 2 when Q 1 and Q 2 of the transition metal compound represented by Formula 1 are halogens. As the second method, when Q 1 and Q 2 of Formula 1 are alkyl radicals, the catalyst can be prepared by contacting the transition metal compound with a mixture of the compounds represented by Formula 3 and Formula 4, or the compounds represented by Formula 3 and Formula 4 can also be directly added to the polymerization reactor to prepare the catalyst.

[0151] The addition amount of the cocatalyst compound can be determined by considering the addition amount of the transition metal compound represented by Formula 1 and the amount required to fully activate the transition metal compound, etc. Relative to 1 mole of the transition metal contained in the transition metal compound represented by Formula 1, the content of the cocatalyst compound can be 1:1 to 100,000 in terms of the molar ratio of the metal contained in the cocatalyst compound, preferably 1:1 to 10,000, and more preferably 1:1 to 5,000.

[0152] More specifically, in the case of the first method, relative to the transition metal compound represented by Chemical Formula 1, the compound represented by Chemical Formula 2 may preferably be included in a molar ratio of 1:10 to 5,000, more preferably in a molar ratio of 1:50 to 1,000, and most preferably in a molar ratio of 1:100 to 1,000. If the molar ratio of the compound represented by Chemical Formula 2 to the transition metal compound of Chemical Formula 1 is lower than 1:10, the amount of aluminoxane is very small, which may cause a problem of incomplete activation of the transition metal compound; if it exceeds 1:5,000, the excessive aluminoxane may act as a catalyst poison, making it difficult for the polymer chain to grow.

[0153] In the case of the second method, when A of the cocatalyst compound represented by Chemical Formula 3 is boron, the cocatalyst compound represented by Chemical Formula 3 may be included in a molar ratio of 1:1 to 100, preferably 1:1 to 10, and more preferably 1:1 to 3, relative to the transition metal compound represented by Chemical Formula 1. In addition, when A of the cocatalyst compound represented by Chemical Formula 3 is aluminum, it may vary depending on the amount of water in the polymerization system, but the cocatalyst compound represented by Chemical Formula 3 may be included in a molar ratio of 1:1 to 1,000, preferably 1:1 to 500, and more preferably 1:1 to 100, relative to the transition metal compound represented by Chemical Formula 1.

[0154] In addition, the cocatalyst compound represented by Chemical Formula 4 may be included in a molar ratio of 1:0.5 to 30, preferably 1:0.7 to 20, and more preferably 1:1 to 10, relative to the transition metal compound represented by Chemical Formula 1. If the ratio of the cocatalyst compound represented by Chemical Formula 4 is lower than 1:0.5, the amount of the activator is relatively small, which may cause a problem of incomplete activation of the metal compound, thereby reducing the activity of the resulting catalyst composition; if it exceeds 1:30, although the activation of the metal compound is fully achieved, the remaining excessive activator may cause a problem of uneconomical cost of the catalyst composition or a decrease in the purity of the resulting polymer.

[0155] On the other hand, the catalyst composition of the present invention including the transition metal compound and the cocatalyst compound may further include a carrier. Here, as the carrier, a carrier of an inorganic or organic material used for catalyst preparation in the technical field to which the present invention pertains can be used without limitation.

[0156] According to the present invention, the carrier may be SiO2, Al2O3, MgO, MgCl2, CaCl2, ZrO2, TiO2, B2O3, CaO, ZnO, BaO, ThO2, SiO2 - Al2O3, SiO2 - MgO, SiO2 - TiO2, SiO2 - V2O5, SiO2 - Cr2O3, SiO2 - TiO2 - MgO, bauxite, zeolite, starch, cyclodextrine or synthetic polymer.

[0157] Preferably, the carrier may be a carrier having hydroxyl groups on its surface, and may be one or more selected from silica (SiO2), silica - alumina (SiO2 - Al2O3) and silica - magnesia (SiO2 - MgO).

[0158] As a method for loading the catalyst comprising the transition metal compound (main catalyst compound) and the cocatalyst compound onto the carrier, the following methods may be used: a method of directly loading the transition metal compound onto the dehydrated carrier; a method of pretreating the carrier with the cocatalyst compound and then loading the transition metal compound; a method of post - treating the transition metal compound loaded onto the carrier with the cocatalyst compound; a method of reacting the transition metal compound with the cocatalyst compound and then adding the carrier for reaction, etc.

[0159] The solvent that can be used in the loading method may be an aromatic hydrocarbon solvent, an aromatic hydrocarbon solvent, a halogenated aliphatic hydrocarbon solvent or a mixture thereof.

[0160] Non - limiting examples of the aliphatic hydrocarbon solvent may include pentane, hexane, heptane, octane, nonane, decane, undecane or dodecane, etc.

[0161] Non - limiting examples of the aromatic hydrocarbon solvent may include benzene, monochlorobenzene, dichlorobenzene, trichlorobenzene or toluene, etc.

[0162] Non-limiting examples of the halogenated aliphatic hydrocarbon solvents include dichloromethane, trichloromethane, dichloroethane, trichloroethane, etc.

[0163] In addition, the loading method is carried out at a temperature of -70°C to 200°C, preferably at -50°C to 150°C, more preferably at 0°C to 100°C, which is beneficial to the efficiency of the loading process.

[0164] On the other hand, in the present invention, the ethylene α-olefin polymer generated by the polymerization process carried out by directly contacting ethylene and an α-olefin comonomer compound can be prepared by the polymerization of monomers under the condition that the polymer chains are rapidly immobilized due to the relatively low solubility and / or fixity of the catalyst sites. This immobilization can be carried out, for example, under the following conditions: using a solid insoluble catalyst, and the generated polymer is usually polymerized in an insoluble medium, and the polymerization reactants and products are maintained below the crystallization temperature (T c ) of the polymer.

[0165] The above catalyst can be preferably applied to the copolymerization of ethylene and α-olefins. The preparation method of the ethylene α-olefin copolymer is described below, which includes the step of copolymerizing ethylene and α-olefins under the catalyst.

[0166] The polymerization processes of ethylene and α-olefins are well known in the art, including bulk polymerization, solution polymerization, slurry polymerization, and low-pressure gas-phase polymerization. The metallocene catalyst composition is particularly useful for the known operating modes of using fixed-bed, fluidized-bed, or slurry polymerization carried out in a single, series, or parallel reactor.

[0167] When carrying out the polymerization reaction in the liquid phase or slurry phase, the solvent, propylene, or the ethylene monomer itself can be used as the medium.

[0168] The catalyst proposed by the present invention exists in a uniform form in the polymerization reactor, so it is preferably applied to the solution polymerization process carried out at a temperature above the melting point of the corresponding polymer. However, as disclosed in U.S. Patent No. 4,752,597, it can also be used in the form of a non-uniform catalyst composition obtained by supporting the transition metal compound and the cocatalyst on a porous metal oxide carrier for slurry polymerization or gas-phase polymerization processes. Therefore, if the catalyst of the present invention is used together with an inorganic carrier or an organic polymer carrier, it can also be used for slurry or gas-phase processes. That is, the transition metal compound and the cocatalyst compound can also be used in the form of being supported on an inorganic carrier or an organic polymer carrier.

[0169] The solvents that can be used in the polymerization reaction can be aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, halogenated aliphatic hydrocarbon solvents, or mixtures thereof. Herein, non-limiting examples of the aliphatic hydrocarbon solvents can include butane, isobutane, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, cyclopentane, methylcyclopentane, cyclohexane, etc. In addition, non-limiting examples of the aromatic hydrocarbon solvents can include benzene, monochlorobenzene, dichlorobenzene, trichlorobenzene, toluene, xylene, chlorobenzene, etc. In addition, non-limiting examples of the halogenated aliphatic hydrocarbon solvents can include dichloromethane, trichloromethane, chloroethane, dichloroethane, trichloroethane, 1,2-dichloroethane, etc.

[0170] As described above, the ethylene α-olefin copolymer of the present invention can be prepared by polymerizing ethylene and an α-olefin comonomer in the presence of the above catalyst composition. At this time, the transition metal compound and the cocatalyst component can be separately introduced into the reactor, or the components can be premixed and then introduced into the reactor, and there are no particular restrictions on the mixing conditions such as the introduction order, temperature, or concentration.

[0171] On the other hand, in the polymerization reaction of the present invention, the addition amount of the catalyst can be determined within the range where the monomer polymerization reaction can occur sufficiently according to the slurry phase, liquid phase, gas phase, or solution process, and thus there is no particular restriction. However, for each unit volume (L) of the monomer, the addition amount of the catalyst based on the concentration of the central metal (M) of the transition metal compound can be from 10 -8 mol / L to 1 mol / L, preferably from 10 -7 mol / L to 10 -1 mol / L, and more preferably from 10 -7 mol / L to 10 -2 mol / L.

[0172] In addition, the polymerization reaction of the present invention can be a batch type, semi - continuous type or continuous type reaction, and is preferably a continuous type reaction.

[0173] The temperature condition of the polymerization reaction of the present invention can be determined according to the type of reaction and reactor applied and considering the efficiency of the polymerization reaction. However, the temperature of the polymerization reaction affects the elution amount of the ethylene α - olefin copolymer during TGIC analysis. Therefore, it is preferably carried out at 130 °C to 160 °C. If the temperature is lower than 130 °C or exceeds 160 °C, the polymerization activity will decrease, which is not advisable.

[0174] On the other hand, the pressure condition of the polymerization reaction can be determined according to the type of reaction and reactor applied and considering the efficiency of the polymerization reaction. The pressure can be 1 - 3000 atmospheres, or 1 - 1000 atmospheres, or 1 - 100 atmospheres, and is preferably 5 - 50 atmospheres.

[0175] The ethylene α - olefin copolymer of the present invention is prepared by the method for preparing the ethylene α - olefin copolymer.

[0176] Although a single metallocene catalyst is used, the ethylene α - olefin copolymer prepared by the above - mentioned method forms an ethylene α - olefin copolymer with two chains having different branch contents due to catalyst isomers. As described above, this is considered to be because the transition metal compound used as the main catalyst in the present invention co - exists two different stereocompounds, an R - type stereocompound and an S - type stereocompound, within one transition metal. The transition metal compound of the S - type stereocompound forms a high - branch - content polymer chain, while the transition metal compound of the R - type stereocompound forms a low - branch - content polymer chain.

[0177] Therefore, the ethylene α - olefin copolymer of the present invention has two chain structures with different branch contents. The branch content represents the number of carbon atoms connected to the branch. The amorphous or low - crystallinity region of the ethylene α - olefin copolymer includes a high - branch - content polymer chain and a low - branch - content polymer chain. The amorphous or low - crystallinity high - branch - content polymer chain can improve the low - temperature impact strength and tensile elongation. On the other hand, due to the increase in the amorphous or low - crystallinity region, physical properties such as tensile strength and shrinkage rate may decrease, but the co - existence of the low - branch - content polymer chain helps to improve physical properties such as the above - mentioned tensile strength and shrinkage rate. Therefore, the ethylene α - olefin copolymer of the present invention has physical properties with improved tensile elongation, tensile strength and shrinkage rate while improving the low - temperature impact strength.

[0178] When the ethylene α-olefin copolymer of the present invention is analyzed by Thermal Gradient Interaction Chromatography (TGIC), due to the different elution temperatures of polymer chains with high content of amorphous or low-crystalline branches and polymer chains with low content of branches, it is eluted at two different temperatures and has two peaks.

[0179] When the ethylene α-olefin copolymer of the present invention is analyzed by Thermal Gradient Interaction Chromatography (TGIC), it has more than two clearly distinguishable elution peaks in the temperature range of 250K to 430K.

[0180] For example, when the ethylene α-olefin copolymer of the present invention is analyzed by TGIC, it can exhibit an elution volume distribution in a bimodal form, which means that there are two kinds of chains with different compositions.

[0181] Specifically, the ethylene α-olefin copolymer of the present invention simultaneously includes chains with a high content of comonomer and chains with a low content of comonomer, so it exhibits an elution volume distribution in a bimodal form during TGIC analysis.

[0182] In addition, the ethylene α-olefin copolymer may have physical properties in a similar range to those of existing ethylene α-olefin copolymers. Specifically, the density may be from 0.850 g / mL to 0.920 g / mL, and the melt index (MI) may be from 0.1 g / 10 min to 50 g / 10 min.

[0183] In addition, the weight-average molecular weight (Mw) of the ethylene α-olefin copolymer may be from 10,000 g / mol to 1,000,000 g / mol, preferably from 50,000 g / mol to 950,000 g / mol, or from 50,000 g / mol to 800,000 g / mol, and more preferably from 10,000 g / mol to 300,000 g / mol.

[0184] In addition, the molecular weight distribution (Mw / Mn) of the ethylene α-olefin copolymer may be from 1 to 10, preferably from 1.5 to 8, and more preferably from 1.5 to 3.

[0185] In addition, the density of the ethylene α-olefin copolymer may be from 0.857 g / ml to 0.903 g / ml.

[0186] The resin composition comprising the ethylene α-olefin copolymer and a polyolefin of the present invention can have high impact strength, especially high and low temperature impact strength and low shrinkage rate without reducing the tensile strength and tensile elongation.

[0187] More specifically, based on the total weight of the resin composition, the resin composition of the present invention comprises 10% to 30% by weight of the ethylene α-olefin copolymer of the present invention, 40% to 80% by weight of a polyolefin, and 10% to 30% by weight of an inorganic filler.

[0188] The inorganic filler can improve the rigidity and dimensional stability of the molded article using the resin composition. The inorganic filler can be, for example, particulate or flaky. Non-limiting examples include mica, silica powder, titanium dioxide, silicate, aluminosilicate. In addition, for example, chalk, wollastonite, montmorillonite (especially the organophilic form modified by ion exchange), talc, kaolin, zeolite, vermiculite, alumina, silica, magnesium hydroxide, aluminum hydroxide, glass flakes, etc. can be used. In addition, a mixture of different inorganic fillers can also be used. Preferred examples can be talc, mica, and combinations thereof. In one implementation example, the inorganic filler can be talc.

[0189] As the type of polyolefin resin, at least one selected from the group including the following resins can be used: a random copolymer resin polymerized from a single monomer selected from the group including propylene, ethylene, butylene, and octane; a block copolymer resin obtained by blending polypropylene with ethylene-propylene rubber; a copolymer resin of polyethylene with ethylene vinyl acetate and α-olefin; and a homopolypropylene resin. However, the examples of polyolefin resins that can be used are not limited thereto.

[0190] In addition, the tensile elongation rate of the ethylene α-olefin copolymer can be 100% to 1000%, and the tensile strength can be 0.1 MPa to 100 MPa.

[0191] A polypropylene resin composition can be prepared by mixing and blending the ethylene α-olefin copolymer of the present invention with a polypropylene resin. When using this polypropylene resin composition to prepare a molded article, the obtained molded article not only has excellent low-temperature impact strength but also has excellent tensile elongation rate, tensile strength, and shrinkage rate characteristics.

[0192] Hereinafter, the present invention will be described in more detail by way of specific examples. The following examples are only examples to help understand the present invention, and the scope of the present invention is not limited thereto.

[0193] Examples

[0194] 1. Synthesis Example - Synthesis of Transition Metal Compound

[0195] Synthesis Example 1

[0196] Starting from compound (1), the transition metal compound (2) used as the main catalyst was synthesized according to the following Reaction Formula 2. The specific synthesis process is as follows.

[0197] [Reaction Formula 2]

[0198]

[0199] First, at -30 °C, methyllithium (1.63 g, 3.55 mmol, 1.6 M diethyl ether solution) was added dropwise to a diethyl ether solution (10 mL) in which compound (1) (0.58 g, 1.79 mmol) was dissolved (step i).

[0200] The solution obtained in step i was stirred at room temperature overnight, then the temperature was lowered to -30 °C, and then Ti(NMe2)2Cl2 (0.37 g, 1.79 mmol) was added to the solution all at once (step ii).

[0201] After the solution obtained in step ii was stirred for three hours, all the solvents were removed using a vacuum pump to obtain a solid product. As a result, a red solid compound (2) (0.59 g, yield 75%) was obtained (step iii).

[0202] By 1 1H NMR spectroscopy, it was confirmed that compound (2) has S-type and R-type isomers, and these two stereoisomers exist.

[0203] 1 1H NMR (C6D6): δ 7.12 and 7.09 (d, J = 7.2 Hz, 1H), 6.96 and 6.94 (d, J = 7.2 Hz, 1H), 6.82 and 6.80 (t, J = 7.2 Hz, 1H), 6.47 and 6.46 (d, J = 7.2 Hz, 1H), 6.45 and 6.44 (d, J = 7.2 Hz, 1H), 5.44 (m, 1H, NCH), 2.76 - 2.60 (m, 1H, CH2), 2.44 - 2.18 (m, 1H, CH2), 2.28 and 2.22 (s, 3H), 2.09 (s, 3H), 1.74 and 1.65 (s, 3H), 1.88 - 1.48 (m, 2H, CH2), 1.20 and 1.18 (d, J = 7.2 Hz, 3H), 0.77 and 0.71 (s, 3H, TiMe), 0.49 and 0.40 (s, 3H, TiMe) ppm.

[0204] 131H NMR (C6D6): δ 159.83, 159.52, 145.93, 144.90, 140.78, 139.93, 139.21, 138.86, 135.26, 131.56, 129.69, 129.57, 127.50, 127.46, 127.38, 127.24, 121.29, 121.16, 120.05, 119.96, 118.90, 118.74, 117.99, 117.74, 113.87, 110.38, 57.91, 55.31, 54.87, 51.68, 50.27, 50.12, 34.77, 27.58, 27.27, 23.10, 22.05, 20.31, 19.90, 16.66, 14.70, 13.11, 12.98, 12.68 ppm. Anal. Calc. (C 22 H 27 NSTi): C, 68.56; H, 7.06; N, 3.63. Found: C, 68.43; H, 7.24; N, 3.52%.

[0205] Synthesis Example 2

[0206] Synthesis was carried out according to the same process as in Synthesis Example 1, but after dissolving the solid product obtained in the said step iii in 8 mL of toluene, 1.16 g (8.96 mmol) of Me2SiCl2 was added (step iii-1).

[0207] The solution obtained in step iii-1 was stirred at 80 °C for three days, and then the solvent was removed using a vacuum pump. As a result, 0.59 g (yield 75%) of a red solid compound (2) was obtained.

[0208] By 1 1H NMR spectroscopy, it was confirmed that two stereoisomers were present in a ratio of 2:1 in the obtained red solid compound.

[0209] 11H NMR (C6D6): δ 7.10 (t, J = 4.4 Hz, 1H), 6.90 (d, J = 4.4 Hz, 2H), 5.27 and 5.22 (m, 1H, NCH), 2.54 - 2.38 (m, 1H, CH2), 2.20 - 2.08 (m, 1H, CH2), 2.36 and 2.35 (s, 3H), 2.05 and 2.03 (s, 3H), 1.94 and 1.93 (s, 3H), 1.89 and 1.84 (s, 3H), 1.72 - 1.58 (m, 2H, CH2), 1.36 - 1.28 (m, 2H, CH2), 1.17 and 1.14 (d, J = 6.4, 3H, CH3) ppm.

[0210] 13 C{ 1 1H} NMR (C6D6): 162.78, 147.91, 142.45, 142.03, 136.91, 131.12, 130.70, 130.10, 128.90, 127.17, 123.39, 121.33, 119.87, 54.18, 26.48, 21.74, 17.28, 14.46, 14.28, 13.80, 13.27 ppm.

[0211] The S - type and R - type isomers of the compound (2) obtained in Synthesis Example 1 and Synthesis Example 2 have the following structures. Thus, when using the transition metal compound of the compound (2) as the main catalyst, since the ethylene conversion rate varies according to the stereostructure of the compound (2), two kinds of polymer chains with different comonomer contents can be formed.

[0212]

[0213] 2. Preparation of ethylene - α - olefin copolymer

[0214] (1) Preparation of ethylene - α - olefin copolymer using the compound (2) obtained in Synthesis Example 1

[0215] Example 1

[0216] After replacing the inside of a high - pressure reactor (internal volume: 2.8 L, stainless steel) with nitrogen at room temperature, 1 L of n - hexane and 2.0 mmol of triisobutylaluminum were added, and then 121.5 g of 1 - butene refined by alumina was added. Then, after injecting 135.0 g of ethylene gas (the 1 - butene / ethylene input ratio was 0.9 by weight), the reactor temperature was pre - heated to 158 °C.

[0217] In a mixed solution containing the solid transition metal compound (7.5 μmol) synthesized in the synthesis example and triisobutylaluminum (187.5 μmol), after mixing the cocatalyst dimethylanilinium tetrakis(pentafluorophenyl)borate (45.0 μmol), it was injected into the reactor, and then a polymerization reaction was carried out for five minutes.

[0218] After the polymerization reaction was completed, the temperature was lowered to room temperature, then the excess ethylene was discharged, and the copolymer dispersed in the solvent was dried in a vacuum oven at a temperature of 80 °C.

[0219] Example 2

[0220] Except that after injecting 135 g of 1-butene and 135.0 g of ethylene gas (the input ratio of 1-butene / ethylene is 1.0 weight ratio), the reactor temperature was preheated to 152 °C, the polymerization reaction was carried out in the same manner as in Example 1 to prepare a copolymer.

[0221] Example 3

[0222] Except that after injecting 162 g of 1-butene and 135.0 g of ethylene gas (the input ratio of 1-butene / ethylene is 1.2 weight ratio), the reactor temperature was preheated to 135 °C, the polymerization reaction was carried out in the same manner as in Example 1 to prepare a copolymer.

[0223] Comparative Example 1

[0224] A commercially available ethylene-1-butene copolymer (LG Chem, LC565) was used.

[0225] The physical properties of Examples 1 to 3 and Comparative Example 1 were measured, and the results are shown in Table 1.

[0226] At this time, for the resin composition, 60% by weight of polypropylene (Lotte Chemical, JM-380), 20% by weight of the ethylene α-olefin copolymer of Example 1 to Example 3 or Comparative Example 1, and 20% by weight of talc were blended using a drum mixer, and then extruded in a single-screw extruder with L / D 35 and a diameter of 40 nm in a temperature range of 190 °C to 230 °C to prepare a resin composition in a granular state. The prepared granular resin composition was molded using an injection molding machine in a temperature range of 190 °C to 240 °C to prepare physical property samples.

[0227] [Table 1]

[0228]

[0229] Examples 1, 2, and 3 are polyolefin copolymers with the same density but different 1-butene (BN-1) contents and showing two elution amounts.

[0230] Example 3 As the 1-butene content increases, the first elution temperature decreases, and the polymers detected at this temperature have a higher number of short chain branches (SCB) and a higher Mw. Based on this, the higher the 1-butene content, the lower the density and the higher the molecular weight of the polymers formed. Thus, the strength properties that may decrease at low density can be compensated for by the high molecular weight, so as to maintain the tensile elongation while increasing the tensile strength and impact strength. Under the conditions of Example 3, it can be interpreted that the [S-type] catalyst with a relatively high comonomer conversion rate is stabilized, and a low-density high-molecular-weight polymer chain is formed due to its long lifetime.

[0231] This result is due to the preparation of the copolymer using the catalyst containing compound (2). Since compound (2) has R-type and S-type isomers as described below, two chains of ethylene α-olefin copolymer with different short chain branch contents are prepared by the catalyst isomers. Therefore, when analyzing the ethylene α-olefin copolymer prepared in the present invention by low-temperature thermal gradient interaction chromatography (TGIC), elution occurs at two different temperatures, so that two chain structures with different short chain branch contents can be confirmed.

[0232] (2) Preparation of ethylene α-olefin copolymer using the compound (2) obtained in Synthesis Example 2

[0233] Examples 4 to 6

[0234] After replacing the inside of a high-pressure reactor (internal volume: 2 L, stainless steel) with nitrogen at room temperature, 1 L of n-hexane and 2 mL of triisobutylaluminum were added. Then, after adjusting the input amounts of 210 ml of 1-octene and ethylene gas and injecting them, the reactor temperature was preheated to 140°C. A solution of dimethylanilinium tetrakis(pentafluorophenyl)borate cocatalyst (45.0 μmol) was mixed in a mixed solution of 1.5 μmol of the synthesized transition metal compound (2) and triisobutylaluminum (187.5 μmol) and then injected into the reactor. Then, a polymerization reaction was carried out for five minutes.

[0235] After the polymerization reaction was completed, the reaction was terminated using ethanol diluted with 10% HCl. Then, the temperature was lowered to room temperature and the excess gas was discharged. Next, the copolymer polymerization solution dispersed in the solvent was transferred to a container, and then dried in a vacuum oven at 80°C for more than 15 hours. The ratio of S-type and R-type was adjusted by catalyst recrystallization to prepare an ethylene / 1-octene copolymer. The results are shown in Table 2.

[0236] [Table 2]

[0237]

[0238] As can be seen from Table 2 above, the higher the proportion of the S-type stereocompound in the transition metal compound that is used as the main catalyst in Examples 4 to 6, the higher the area ratio of the first fraction (polymer chains with a high branch content) to the area ratio of the second fraction (polymer chains with a low branch content) of the ethylene α-olefin copolymer obtained.

[0239] On the other hand, the ratio obtained as the result value of the area ratio of Te-1 / area ratio of Te-2 in Table 2 above corresponds to the ratio of the elution amount at the first elution temperature / elution amount at the second elution temperature.

[0240] This indicates that although a single catalyst is used, due to the presence of isomers, by adjusting the ratio of the S-type and R-type, the polymer structure formed can be adjusted, and thus the physical properties of the polymer can be adjusted.

[0241] Examples 7 and 8

[0242] After replacing the inside of a high-pressure reactor (internal volume: 2 L, stainless steel) with nitrogen at room temperature, 1 L of n-hexane and 2 mL of triisobutylaluminum were added. Then, after adjusting the input amounts of 1-butene and ethylene gases and injecting them, the reactor temperature was preheated to 140 °C. A solution of a dimethylanilinium tetrakis(pentafluorophenyl)borate cocatalyst (45.0 μmol) was mixed with a mixed solution of the synthesized transition metal compound (2) (1.5 μmol) and triisobutylaluminum (187.5 μmol) and then injected into the reactor. After that, a polymerization reaction was carried out for five minutes.

[0243] After the polymerization reaction ended, the reaction was terminated using ethanol diluted with 10% HCl. Then, the temperature was lowered to room temperature and the excess gas was discharged. Next, the copolymer polymerization solution dispersed in the solvent was transferred to a container, and then dried in a vacuum oven at 80 °C for more than 15 hours to prepare ethylene / 1-butene copolymers respectively.

[0244] The physical properties of the prepared ethylene / 1-butene copolymers were measured, and the results are shown in Table 2.

[0245] Comparative Example 2

[0246] An ethylene-1-butene copolymer (LC175) commercially produced by LG Chem was purchased, and its physical properties were measured. The results are shown in Table 3.

[0247] [Table 3]

[0248]

[0249] As can be seen from Table 3 above, the ethylene α-olefin copolymers of Example 7 and Example 8 simultaneously include a first fraction (highly branched polymer chains) and a second fraction (lowly branched polymer chains) defined by a first peak and a second peak that are clearly distinguishable from each other in the TGIC analysis results.

[0250] In addition, the fraction ratio in the first peak region is higher than that in the second peak region, and the average SCB content is higher, indicating that more comonomers are introduced in the first peak region than in the second peak region.

[0251] This indicates that the main catalyst used in Example 7 and Example 8, i.e., the transition metal compound, functions as two catalysts with different structures of R-type stereocompounds and S-type stereocompounds, thereby forming highly branched and high molecular weight polymer chains with a lower elution temperature and polymer chains with a low branched content.

[0252] This difference in the branched content also causes a difference in crystallinity. The highly branched polymer chains have amorphous or low crystallinity, while the lowly branched chains have high crystallinity. This means that the copolymers of the above examples simultaneously include two types of chains with significantly different crystallinities due to the difference in the branched content.

[0253] 3. Physical Property Analysis of Copolymer and Resin Composition

[0254] (1) Density (g / mL)

[0255] Using the copolymer treated with an antioxidant, a sheet with a thickness of 3 mm and a radius of 2 cm was prepared by compression molding at 180 °C, and after cooling to room temperature, it was measured according to ASTM D-792 (manufacturer: Toyoseiki, model: T-001).

[0256] (2) Melt Index (MI)

[0257] It was measured according to ASTM D-1238 (condition E, 190 °C, 2.16 kg load) (manufacturer: Mirage, model: SD-120L).

[0258] (3) Low-temperature TGIC (Thermal Gradient Interaction Chromatography) Analysis

[0259] The copolymer was dissolved in 1,2,4-trichlorobenzene and then injected into the instrument (manufacturer: PolymerChar, model: CFC). After that, the temperature was increased from 250K to 430K in 5°C increments, and elution was carried out through the GPC column at a flow rate of 1 ml / min. The amount of polymer, the degree of SCB (Short Chain Branch), and Mw were measured using an infrared detector at each temperature.

[0260] (4) Tensile elongation at break

[0261] Measurement was carried out using a universal material testing machine (INSTRON 4466) according to the method of ASTM D638.

[0262] (5) Tensile strength

[0263] Measurement was carried out using a universal material testing machine (INSTRON 4466) according to the method of ASTM D638.

[0264] (7) IZOD impact strength (23°C)

[0265] The notched impact strength of 1 / 8" samples was measured at 23°C according to the method of ASTM D256.

[0266] (8) IZOD impact strength (-10°C)

[0267] The notched impact strength of 1 / 8" samples was measured at -10°C according to the method of ASTM D256.

[0268] (9) IZOD impact strength (-30°C)

[0269] The notched impact strength of 1 / 8" samples was measured at -30°C according to the method of ASTM D256.

[0270] (10) Molecular weight distribution (Mw)

[0271] Analysis was carried out by gel permeation chromatography (GPC, Gel Permeation Chromatography, equipment name: PL-GPC220, manufacturer: Agilent) at 160°C using 1,2,4-trichlorobenzene solvent.

[0272] (11) Melting point (Tm)

[0273] Using a differential scanning calorimeter (DSC, model: DSC2920, manufacturer: TA), the DSC was measured as follows: After reaching equilibrium at 0 °C, the temperature was increased to 200 °C at a rate of 10 °C per minute, then decreased to -90 °C at a rate of 10 °C per minute, and then increased to 200 °C again at a rate of 10 °C per minute. The melting point was obtained by taking the top region of the endothermic curve during the second heating process.

[0274] (12) Comonomer content (wt%)

[0275] By 1 1H NMR (equipment name: Avance DRX400, manufacturer: Bruker) analysis.

[0276] (13) TGIC analysis

[0277] Using the cross-fractionation chromatography (CFC) equipment of Polymer Char Company, the sample to be analyzed was dissolved in 1,2,4-trichlorobenzene (2.5 mg / mL) by stirring at 150 °C for 60 minutes. Then, the dissolved sample was introduced into the TGIC (Thermal Gradient Interaction Chromatography) column at a rate of 1 mL / min, and then stabilized at 150 °C for 20 minutes. Subsequently, the TGIC column was cooled to 35 °C (250 K) at a cooling rate of 20 °C / min. The temperature was increased in 5 °C increments from 35 °C to 130 °C, and eluted through the GPC column at a flow rate of 1 mL / min. The elution time at this time was five minutes, and the analysis time for each fraction was 20 minutes. After passing through the GPC column, an infrared detector (IR5) was used to determine the elution volume at temperature fractionation, the molecular weight and branch chain distribution of the polymer corresponding to each fraction. The peak area of each fraction was confirmed using the analysis software "CFCcalc", and n-heptane was used as the internal standard at this time.

[0278] The S-type / (S-type + R-type) ratio, S-type:R-type molar ratio, area ratio of Te-1 (%), and area ratio of Te-2 (%) of the copolymers obtained in Examples 1 to 8 of the present invention were sorted out and shown in Table 4 below.

[0279] [Table 4]

[0280]

[0281] The embodiments of the present invention have been described in detail above, but the scope of the rights of the present invention is not limited thereto. Various modifications and variations can be made without departing from the technical idea of the present invention recorded in the claims, which will be obvious to those skilled in the art.

Claims

1. An ethylene α-olefin copolymer comprising ethylene structural units and α-olefin structural units, wherein, when subjected to thermal gradient interaction chromatography (TGIC) analysis, the ethylene α-olefin copolymer comprises more than two mutually different elution peaks in the temperature range of 250 K to 430 K.

2. The ethylene α-olefin copolymer according to claim 1, wherein, when including two mutually different elution peaks, it has a first elution temperature and a second elution temperature during thermal gradient interaction chromatography (TGIC) analysis, and the difference between the first elution temperature and the second elution temperature is 10 K to 60 K.

3. The ethylene α-olefin copolymer according to claim 2, wherein, the first elution temperature is 310 K to 345 K, and the second elution temperature is 350 K to 380 K.

4. The ethylene α-olefin copolymer according to claim 2, wherein, the ratio of the first elution temperature to the second elution temperature is 0.5 to 0.

91.

5. The ethylene α-olefin copolymer according to claim 2, wherein, the ratio of the elution amount at the first elution temperature to the elution amount at the second elution temperature is 0.5 to 7.

3.

6. The ethylene α-olefin copolymer according to claim 1, wherein, the density of the ethylene α-olefin copolymer is 0.857 g / ml to 0.903 g / ml.

7. A method for preparing an ethylene α-olefin copolymer for preparing the ethylene α-olefin copolymer according to any one of claims 1 to 6, comprising the following steps: polymerizing ethylene with at least one olefin monomer in the presence of a main catalyst compound comprising a transition metal compound represented by the following Chemical Formula 1 and one or more cocatalysts selected from the compounds represented by the following Chemical Formula 2 to Chemical Formula 4, [Chemical Formula 1] In the above Chemical Formula 1, M is a Group 4 transition metal, Q 1 and Q 2 are each independently halogen, (C1-C 20 )alkyl, (C2-C 20 )alkenyl, (C2-C 20 )alkynyl, (C6-C 20 )aryl, (C1-C 20 )alkyl(C6-C 20 )aryl, (C6-C 20 )aryl(C1-C 20 )alkyl, (C1-C 20 )alkylamido, (C6-C 20 )arylamido or (C1-C 20 )alkylene, R 1 、R 2 、R 3 、R 4 、R 5 、R 6 、R 7 、R 8 、R 9 and R 10 are each independently hydrogen; (C1-C 20 )alkyl which may or may not include an acetal, ketal or ether group; (C2-C 20 )alkenyl which may or may not include an acetal, ketal or ether group; (C1-C 20 )alkyl(C6-C 20 )aryl which may or may not include an acetal, ketal or ether group; (C6-C 20 )aryl(C1-C 20 )alkyl which may or may not include an acetal, ketal or ether group; or (C1-C 20 )alkylsilyl which may or may not include an acetal, ketal or ether group, wherein the R 1 and the R 2 may be connected to each other to form a ring, the R 3 and the R 4 may be connected to each other to form a ring, and two or more of the R 5 to the R 10 may be connected to each other to form a ring, R 11 、R 12 and R 13 are each independently hydrogen; (C1-C 20 )alkyl which may or may not include an acetal, ketal or ether group; (C2-C 20 )alkenyl which may or may not include an acetal, ketal or ether group; (C1-C 20 )alkyl(C6-C 20 )aryl which may or may not include an acetal, ketal or ether group; (C6-C 20 )aryl(C1-C 20 )alkyl which may or may not include an acetal, ketal or ether group; (C1-C 20 )alkylsilyl; (C1-C 20 )alkoxy; or (C6-C 20 )aryloxy, provided that said R 11 and said R 12 or said R 12 and said R 13 may be connected to each other to form a ring, [Chemical Formula 2] -[Al(Ra)-O] n - In the above Chemical Formula 2, Ra is independently a halogen; or a (C1-C 20 ) hydrocarbyl group which is substituted or unsubstituted by a halogen, n is an integer of 2 or more, [Chemical Formula 3] Q(Rb)3 In the above Chemical Formula 3, Q is aluminum or boron, Rb is independently a halogen; or a (C1-C 20 ) hydrocarbyl group which is substituted or unsubstituted by a halogen, [Chemical Formula 4] [W] + [Z(Rc)4] - In the above Chemical Formula 4, [W] + is a cationic Lewis acid; or a cationic Lewis acid bonded to a hydrogen atom, Z is a Group 13 element, Rc is independently selected from aryl groups having one or more substituents selected from halogen, (C1-C 20 ) hydrocarbyl, alkoxy and phenoxy groups and substituted by one or more substituents selected from halogen, (C1-C 20 ) hydrocarbyl, alkoxy and phenoxy groups; alkyl groups having one or more substituents selected from halogen, (C1-C 20 ) hydrocarbyl, alkoxy and phenoxy groups and substituted by one or more substituents selected from halogen, (C1-C 20 ) hydrocarbyl, alkoxy and phenoxy groups.

8. The process for preparing an ethylene α-olefin copolymer according to claim 7, wherein, the transition metal compound is a compound in which R-type and S-type stereocompounds coexist.

9. A polypropylene resin composition comprising: polypropylene; and the ethylene α-olefin copolymer according to any one of claims 1 to 6.

10. A molded article prepared from the resin composition according to claim 9.

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