Ethylene copolymer and its production method, composition, crosslinked polymer and tire

Abstract

The present invention discloses an ethylene copolymer, a method for producing the same, and a composition, a crosslinked polymer, and a tire containing the ethylene copolymer. The ethylene copolymer contains ethylene structural units derived from ethylene and conjugated diolefin structural units derived from a conjugated diolefin, wherein the content of the conjugated diolefin structural units is 25 to 45 mol % based on the total amount of the ethylene copolymer, the content of 1,2-polymerized vinyl structural units having side chain double bonds formed by 1,2-polymerization of the conjugated diolefin is 20 to 40 mol %, the total amount of the 1,2-polymerized structural units is 95 mol % or more based on the total amount of the conjugated diolefin structural units in the ethylene copolymer, and the weight average molecular weight of the ethylene copolymer is 20,000 to 300,000. The ethylene copolymer according to the present invention has good crosslinking performance.

Description

Detailed Description of the Invention

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of Chinese patent applications 202011311765.9 and 202011314968.3, filed on November 20, 2020, the contents of which are incorporated herein by reference.

[0002] [Technical field] The present invention relates to an ethylene copolymer and a method for producing the same. More specifically, the present invention relates to an ethylene copolymer containing structural units derived from ethylene and structural units derived from a conjugated diolefin and a method for producing the same. The present invention also relates to a composition containing the ethylene copolymer and a crosslinked polymer containing units derived from the ethylene copolymer. The present invention further relates to a tire having at least one component containing the ethylene copolymer, the composition or the crosslinked polymer.

[0003] [Background technology] Ethylene is widely used in the plastics industry as a monomer that is used in large quantities and is easily available. Conjugated diolefins, especially butadiene and isoprene, are the most important monomers for synthesizing rubber. Butadiene, as a by-product of the process of producing ethylene through the petroleum route, was once close in price to ethylene. Recently, due to changes in the ethylene production route, the production volume of butadiene has decreased and its price has risen significantly. In comparison, the price of ethylene has been kept low. Therefore, the use of ethylene as a raw material for tire rubber has attracted attention, and it can significantly reduce raw material costs.

[0004] However, copolymerization of conjugated dienes and α-olefins has been difficult because of the different polymerization mechanisms between them. Therefore, it has been an extremely difficult task to catalyze the copolymerization of ethylene and conjugated dienes using conventional catalyst systems, and the realization of the copolymerization of the two has been undertaken by both academia and industry.

[0005] The main problem with the conventional copolymerization method of ethylene and conjugated diolefin is that the content of conjugated diolefin structural units in the produced polymer is low and the content of unsaturated bonds in the main chain of the produced polymer is high, which makes it difficult to improve physical properties such as weather resistance, heat resistance, and ozone resistance.

[0006] Therefore, in order to improve the catalytic activity, the molecular weight of the polymer, and the content of the conjugated diolefin structural unit in the polymer, there is an urgent need to develop a polymerization process suitable for copolymerization of ethylene with a conjugated diolefin.

[0007] [Summary of the Invention] [Problem to be solved by the invention] An object of the present invention is to provide an ethylene copolymer containing conjugated diolefin structural units derived from a conjugated diolefin, which has a high content of conjugated diolefin structural units, a high content of 1,2-polymerized vinyl structural units having side chain double bonds formed by 1,2-polymerization of the conjugated diolefin, and a low content of unsaturated bonds in the main chain of the copolymer.

[0008] [Means for solving the problem] According to a first aspect of the present invention, there is provided a method for producing ... composition comprising the steps of: An ethylene copolymer, The present invention provides an ethylene copolymer comprising ethylene structural units derived from ethylene and conjugated diolefin structural units derived from a conjugated diolefin, the content of the conjugated diolefin structural units being 25 to 45 mol % based on the total amount of the ethylene copolymer, the content of 1,2-polymerized vinyl structural units formed by 1,2-polymerization of a conjugated diolefin and having a side chain double bond being 20 to 40 mol %, the total amount of the 1,2-polymerized structural units being 95 mol % or more based on the total amount of conjugated diolefin structural units in the ethylene copolymer, and the weight average molecular weight of the ethylene copolymer being 20,000 to 300,000.

[0009] According to a second aspect of the present invention, there is provided a method for producing an ethylene copolymer, comprising the step of contacting ethylene with a conjugated diolefin in the presence of a polymerization catalyst containing Component A selected from metal compounds represented by Formula 1 and Component B which is an aluminoxane.

[0010] [ka]

[0011] (In formula 1, M is selected from metal atoms of Group 4; X1 and X2 are the same or different and each independently represents a halogen atom; Rb is a divalent group containing a Group 14 element, L1 and L2 are the same or different and are each independently selected from groups represented by formulas 3 to 6;

[0012] [ka] JPEG0007621483000003.jpg192169

[0013] In formula 3, R A 1 , R A 2 , R A 3 , R A 4 and R A 5 are the same or different and each independently represents a hydrogen atom or a C-C 20 is an alkyl group of In formula 4, R B 1 , R B 2 , R B 3 , R B 4 and R B 5 are the same or different and each independently represents a hydrogen atom or a C-C 20 is an alkyl group of In formula 5, R C 1 , R C 2 , R C 3 and R C 4 are the same or different and each independently represents a hydrogen atom or a C-C 20 is an alkyl group of In formula 6, R D 1 , R D 2 , R D 3 and R D 4 are the same or different and each independently represents a hydrogen atom or a C-C 20 is an alkyl group.) According to a third aspect of the present invention, there is provided an ethylene copolymer produced by the process according to the second aspect of the present invention.

[0014] According to a fourth aspect of the present invention, there is provided a composition comprising an ethylene copolymer and a crosslinking agent, the ethylene copolymer being the ethylene copolymer according to the first or third aspect of the present invention.

[0015] According to a fifth aspect of the present invention, there is provided a crosslinked polymer containing units derived from an ethylene copolymer according to the first or third aspect of the present invention.

[0016] According to a sixth aspect of the present invention, there is provided a tyre, at least one component of which comprises an ethylene copolymer according to the first or third aspect of the present invention, a composition according to the fourth aspect of the present invention, or a crosslinked polymer according to the fifth aspect of the present invention.

[0017] [Effects of the invention] The ethylene copolymer of the present invention has a high content of conjugated diolefin structural units, a high content of 1,2-polymerized vinyl structural units, and a low content of unsaturated double bonds in the main chain of the copolymer. The ethylene copolymer of the present invention has good crosslinking performance, and the crosslinked product has excellent weather resistance, heat resistance, and ozone resistance. The ethylene copolymer of the present invention is expected to be used in the rubber field, especially in the field of vehicle tire rubber.

[0018] The process for producing the ethylene copolymer according to the present invention not only enables the production of the ethylene copolymer according to the present invention, but also provides improved catalytic activity, improves production efficiency, and is suitable for industrial mass production.

[0019] [Mode for carrying out the invention] The range endpoints and any values ​​disclosed herein should be understood not to be limited to the exact range or value, but to include values ​​close to these ranges or values. In the case of numerical ranges, the values ​​between the endpoints of each range, between the endpoints of each range and the individual point values, and between the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed herein.

[0020] According to a first aspect of the present invention, there is provided an ethylene copolymer containing ethylene structural units derived from ethylene and conjugated diolefin structural units derived from a conjugated diolefin.

[0021] In the present invention, the term "structural unit derived from ethylene" means a structural unit formed from ethylene and having the same type of atoms and the same number of atoms as those of ethylene except that the electronic structure is changed, and the term "structural unit derived from conjugated diolefin" means a structural unit formed from conjugated diolefin and having the same type of atoms and the same number of atoms as those of conjugated diolefin except that the electronic structure is changed.

[0022] In the ethylene copolymer according to the present invention, the conjugated diolefin is a compound having a molecular structure containing a conjugated double bond. The conjugated diolefin may be one or more compounds selected from the compounds represented by formula 11.

[0023] [ka]

[0024] (In formula 11, R3, R4 and R5 are the same or different and are each selected from hydrogen and C1-C5 linear or branched alkyl.) In the ethylene copolymer according to the present invention, specific examples of the conjugated diolefin include, but are not limited to, butadiene and / or isoprene. Preferably, the conjugated diolefin is butadiene.

[0025] In the ethylene copolymer according to the present invention, the content of the conjugated diolefin structural unit may be 25 to 45 mol%, for example, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44 or 45 mol%, based on the total amount of the ethylene copolymer. Preferably, the content of the conjugated diolefin structural unit is 25 to 40 mol%, based on the total amount of the ethylene copolymer. More preferably, the content of the conjugated diolefin structural unit is 30 to 35 mol%, based on the total amount of the ethylene copolymer.

[0026] In the ethylene copolymer according to the present invention, the conjugated diolefin structural unit is a 1,2-polymerized structural unit formed substantially by 1,2-polymerization of a conjugated diolefin, and therefore, in the ethylene copolymer according to the present invention, the content of 1,2-polymerized structural units is high, and the content of unsaturated double bonds in the main chain of the copolymer is low. In the ethylene copolymer according to the present invention, based on the total amount of conjugated diolefin units in the ethylene copolymer, the total amount of the 1,2-polymerized structural units is 95 mol% or more, preferably 98 mol% or more, more preferably 100 mol%. In the ethylene copolymer according to the present invention, the content of double bonds in the main chain of the ethylene copolymer is generally 5 mol% or less, preferably 2 mol% or less, more preferably 0 mol%. The double bonds in the main chain of the ethylene copolymer may be derived from structural units formed by, for example, 1,4-polymerization or 1,3-polymerization of a conjugated diolefin.

[0027] In the present invention, a 1,2-polymerized structural unit is a structural unit formed by 1,2-polymerization (i.e., 1,2-addition) of a conjugated diolefin, a 1,4-polymerized structural unit is a structural unit formed by 1,4-polymerization (i.e., 1,4-addition) of a conjugated diolefin, and a 1,3-polymerized structural unit is a structural unit formed by 1,3-polymerization (i.e., 1,3-addition) of a conjugated diolefin.

[0028] In the ethylene copolymer according to the present invention, the 1,2-polymerized structural units include a 1,2-polymerized vinyl structural unit formed by the 1,2-polymerization of a conjugated diolefin and having a side chain double bond, a 1,2-cyclopropane ring structural unit formed by the 1,2-polymerization of a conjugated diolefin and having a cyclopropane ring, and a 1,5-cyclopentane ring structural unit formed by the 1,2-polymerization of a conjugated diolefin and having a cyclopentane ring.

[0029] Taking butadiene as an example, the 1,2-vinyl structural unit is shown in Formula 14, the 1,2-cyclopropane ring structural unit is shown in Formula 15, and the 1,5-cyclopentane ring structural unit is shown in Formula 16.

[0030] [ka]

[0031] The ethylene copolymer according to the present invention has a high content of 1,2-polymerized vinyl structural units having side chain double bonds formed by 1,2-polymerization of conjugated diolefins. Based on the total amount of the ethylene copolymer according to the present invention, the content of 1,2-polymerized vinyl structural units (i.e., vinyl content) may be 20 to 40 mol%, for example, 20, 20.5, 21, 21.5, 22, 22.5, 23, 23.5, 24, 24.5, 25, 25.5, 26, 26.5, 27, 27.5, 28, 28.5, 29, 29.5, 30, 30.5, 31, 31.5, 32, 32.5, 33, 33.5, 34, 34.5, 35, 35.5, 36, 36.5, 37, 37.5, 38, 38.5, 39, 39.5, or 40 mol%. Preferably, the content of the 1,2-polymerized vinyl structural unit is 20 to 35 mol % based on the total amount of the ethylene copolymer according to the present invention, and more preferably, the content of the 1,2-polymerized vinyl structural unit is 21 to 30 mol % based on the total amount of the ethylene copolymer according to the present invention.

[0032] In the ethylene copolymer according to the present invention, the content of the 1,2-polymerized vinyl structural unit reaches 55% or more, preferably 55 to 90%, for example, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89 or 90%, based on the total amount of the conjugated diolefin structural units in the ethylene copolymer. Preferably, the content of the 1,2-polymerized vinyl structural unit is 60 to 88%, based on the total amount of the conjugated diolefin structural units in the ethylene copolymer. More preferably, the content of the 1,2-polymerized vinyl structural unit is 63 to 85%, based on the total amount of the conjugated diolefin structural units in the ethylene copolymer.

[0033] In the ethylene copolymer according to the present invention, the molar ratio of 1,2-cyclopentane ring structural units to 1,2-cyclopropane ring structural units in the conjugated diolefin structural units of the copolymer is 0.1 to 3:1, preferably 0.3 to 2.5:1, more preferably 0.4 to 2:1, and further preferably 0.5 to 1.8:1.

[0034] In the present invention, the microstructural composition of the ethylene copolymers is measured by nuclear magnetic resonance spectroscopy.

[0035] The ethylene copolymer according to the present invention not only has a high content of 1,2-polymerized vinyl structural units, but also has a high molecular weight. w ) is 20,000 to 300,000, preferably 25,000 to 250,000, more preferably 30,000 to 200,000, and further preferably 40,000 to 150,000. w / M n ) is 3.5 or less, preferably 3.2 or less, and more preferably 1.5 to 3.

[0036] In the present invention, the molecular weight (g / mol) and the molecular weight distribution index are measured by gel permeation chromatography (GPC) using monodisperse polystyrene as the standard substance.

[0037] In the ethylene copolymer according to the present invention, the glass transition temperature (T g ) may be in the range of -50°C to -15°C, but is preferably in the range of -40°C to -20°C.

[0038] In the present invention, the glass transition temperature is measured by differential scanning calorimetry (DSC).

[0039] According to a second aspect of the present invention, there is provided a process for producing an ethylene copolymer comprising the step of contacting ethylene with a conjugated diolefin in the presence of a polymerization catalyst.

[0040] In the production method according to the present invention, the conjugated diolefin refers to a compound having a molecular structure containing a conjugated double bond. The conjugated diolefin may be one or more compounds selected from the compounds represented by formula 11.

[0041] [ka]

[0042] (In formula 11, R3, R4 and R5 are the same or different and are each selected from hydrogen and C1-C5 linear or branched alkyl.) In the production method according to the present invention, specific examples of the conjugated diolefin include, but are not limited to, butadiene and / or isoprene. Preferably, the conjugated diolefin is butadiene.

[0043] In the production method according to the present invention, the polymerization catalyst contains Component A and Component B.

[0044] The component A is selected from metal compounds represented by formula 1.

[0045] [ka]

[0046] (In formula 1, M is selected from metal atoms of Group 4 and may be a titanium atom, a zirconium atom, or a hafnium atom. Preferably, in formula 1, M is a zirconium atom. In formula 1, X1 and X2 are the same or different and each independently represent a halogen atom. Preferably, in formula 1, X1 and X2 are both chlorine atoms. In formula 1, Rb is a divalent group of an element of Group 14. 、 Preferably, it is a silicon-containing divalent group, more preferably a divalent group represented by formula 2:

[0047] [ka]

[0048] In formula 2, R 1 and R 2 are the same or different, and each independently represents C1-C 10 The alkyl group is C1-C 10 The alkyl group is C1-C 10 Straight chain alkyl, C3-C 10 Branched alkyl and C3-C 10 Specific examples of cycloalkyl include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, s-butyl, isobutyl, t-butyl, pentyl and its various isomers, hexyl and its various isomers, heptyl and its various isomers, octyl and its various isomers, nonyl and its various isomers, decyl and its various isomers, cyclopropyl, cyclobutyl, cyclopentyl, or cyclohexyl. Preferably, in formula 2, R 1 and R 2 are all methyl.

[0049] In formula 1, L1 and L2 are the same or different and are each independently selected from the groups represented by formulas 3 to 6.

[0050] [ka]

[0051] (In formula 3, R A 1 , R A 2 , R A 3 , R A 4 and R A 5 are the same or different and each independently represents a hydrogen atom or a C-C 20 is an alkyl group.) In the present invention, C1-C 20 The alkyl group is C1-C 20Straight chain alkyl, C3-C 20 Branched alkyl, and C3-C 20 cycloalkyl, specific examples of which may include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, s-butyl, isobutyl, t-butyl, pentyl and its various isomers, hexyl and its various isomers, heptyl and its various isomers, octyl and its various isomers, nonyl and its various isomers, decyl and its various isomers, undecyl and its various isomers, dodecyl and its various isomers, tridecyl and its various isomers, tetradecyl and its various isomers, pentadecyl and its various isomers, hexadecyl and its various isomers, heptadecyl and its various isomers, octadecyl and its various isomers, nonadecyl and its various isomers, eicosyl and its various isomers, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl.

[0052] In one embodiment, in formula 3, R A 1 , R A 2 , R A 3 , R A 4 and R A 5 is also a hydrogen atom.

[0053] In another embodiment, in formula 3, R A 1 , R A 2 , R A 3 , R A 4 and R A 5 are each independently a hydrogen atom or a C1-C 20 and R A 1 , R A 2 , R A 3 , R A 4 and R A5 and cannot be hydrogen atoms at the same time. A 1 , R A 2 , R A 3 , R A 4 and R A 5 At least one (preferably two) of the 10 More preferably, it is C1-C6 alkyl, even more preferably C1-C3 alkyl, and more preferably methyl, and the remaining groups are hydrogen atoms.

[0054] In formula 4, R B 1 , R B 2 , R B 3 , R B 4 and R B 5 are the same or different and each independently represents a hydrogen atom or a C-C 20 is an alkyl group.

[0055] In one embodiment, in formula 4, R B 1 , R B 2 , R B 3 , R B 4 and R B 5 is also a hydrogen atom.

[0056] In another embodiment, in formula 4, R B 1 , R B 2 , R B 3 , R B 4 and R B 5 are each independently a hydrogen atom or a C1-C 20 and R B 1 , RB 2 , R B 3 , R B 4 and R B 5 cannot be a hydrogen atom at the same time. In this embodiment, R B 1 , R B 2 , R B 3 , R B 4 and R B 5 At least one (preferably two, more preferably R B 2 and R B 4 ) is preferably C1-C 10 More preferably, it is C1-C6 alkyl, even more preferably C1-C3 alkyl, and more preferably methyl, and the remaining groups are hydrogen atoms.

[0057] In formula 5, R C 1 , R C 2 , R C 3 and R C 4 are the same or different and each independently represents a hydrogen atom or a C-C 20 is an alkyl group.

[0058] In a preferred embodiment, in formula 5, R C 1 , R C 2 , R C 3 and R C 4 At least one (preferably two, more preferably R C 1 and R C 3 ) is C1-C 20alkyl, preferably C1-C6 alkyl, more preferably C1-C3 alkyl, even more preferably methyl, ethyl, n-propyl or isopropyl, and the remaining groups are hydrogen atoms. According to this preferred embodiment, in one more preferred example, R C 1 is methyl, R C 3 is ethyl or n-propyl, R C 2 and R C 4 is a hydrogen atom.

[0059] In formula 6, R D 1 , R D 2 , R D 3 and R D 4 are the same or different and each independently represents a hydrogen atom or a C-C 20 is an alkyl group.

[0060] In a preferred embodiment, in formula 6, R D 1 , R D 2 , R D 3 and R D 4 At least one (preferably two, more preferably R D 1 and R D 3 ) is C1-C 20 alkyl, preferably C1-C6 alkyl, more preferably C1-C3 alkyl, even more preferably methyl, ethyl, n-propyl or isopropyl, and the remaining groups are hydrogen atoms. According to this preferred embodiment, in one more preferred example, R D 1 is methyl, R D 3 is ethyl or n-propyl, R D 2 and R D 4 is a hydrogen atom.

[0061] In the production method according to the present invention, the component A is preferably one or more metal compounds selected from the metal compounds represented by formulae 7 to 10.

[0062] [ka]

[0063] In a more preferred embodiment, the component A is selected from the metal compounds represented by formula 7 and formula 8. According to this more preferred embodiment, the method according to the present invention not only improves the content of conjugated diolefin structural units derived from conjugated diolefins and structural units formed by 1,2-polymerization of conjugated diolefins in the ethylene copolymer, but also provides higher catalytic activity and the produced ethylene copolymer has a higher molecular weight.

[0064] In another more preferred embodiment, the component A is selected from the metal compounds represented by formula 9 and formula 10. In such a preferred embodiment, the method according to the present invention can polymerize more conjugated diolefins by 1,2-polymerization under conditions that provide high catalytic activity, thereby providing ethylene copolymers having a higher content of 1,2-polymerized structural units.

[0065] In the production method according to the present invention, the metal compound as the component A may be purchased as a commercial product or may be produced by a general method.

[0066] In the method of the present invention, the component B contains an aluminoxane, preferably an organoaluminoxane, more preferably a methylaluminoxane. In a preferred embodiment, the component B is an aluminoxane, preferably an organoaluminoxane, more preferably a methylaluminoxane.

[0067] In the production method according to the present invention, the molar ratio of the component A to the component B may be 1:0.1 to 5000, but is preferably 1:1 to 3000, more preferably 1:1 to 1000, even more preferably 1:10 to 1000, and even more preferably 1:100 to 800.

[0068] In the production method according to the present invention, the amount of the component A used may be 0.1 to 100 μmol, preferably 1 to 80 μmol, more preferably 3 to 60 μmol, and further preferably 5 to 30 μmol, per 1 mol of the conjugated diolefin.

[0069] In the production process according to the present invention, the contact between ethylene and the conjugated diolefin may be carried out at a temperature of from -50° C. to 150° C., but is preferably carried out at a temperature of from 10 to 120° C., more preferably from 30 to 90° C., and even more preferably from 40 to 70° C. In the production process according to the present invention, when ethylene is contacted with the conjugated diolefin to polymerize it, the pressure of ethylene may be from 0 to 100 MPa, but is preferably from 2 to 50 MPa, more preferably from 3 to 30 MPa, and even more preferably from 5 to 10 MPa, and the pressure is a cage (G) pressure.

[0070] In the production method according to the present invention, the contact is carried out in the presence of a molecular weight regulator, and depending on the amount of the molecular weight regulator used, the weight average molecular weight of the produced olefin polymer is 20,000 to 300,000, preferably 25,000 to 250,000, more preferably 30,000 to 200,000, and further preferably 40,000 to 150,000. The molecular weight regulator may be a common one, but is preferably hydrogen gas.

[0071] The process according to the present invention may be carried out by solution polymerization. In solution polymerization, solvents that can be used include C6-C 12 Aromatic hydrocarbons, C6-C 12 Halogenated aromatic hydrocarbons, C5-C 10 Normal alkanes, and C5-C 10cycloalkanes such as one or more of toluene, chlorobenzene, dichlorobenzene, n-hexane, and cyclohexane.

[0072] According to a third aspect of the present invention, there is provided an ethylene copolymer produced by the process according to the second aspect of the present invention.

[0073] The ethylene copolymer prepared by the method according to the second aspect of the present invention has a high content of conjugated diolefin structural units as well as a high content of structural units formed by 1,2-polymerization of conjugated diolefins, and therefore the ethylene copolymer according to the third aspect of the present invention has a low content of unsaturated double bonds in the molecular main chain and has good weather resistance, heat resistance and ozone resistance.More importantly, the ethylene copolymer according to the third aspect of the present invention has a high content of 1,2-polymerized vinyl structural units, and therefore has better vulcanization performance, exhibiting a faster vulcanization rate and a higher vulcanization degree.

[0074] Based on the total amount of the ethylene copolymer described in the third aspect of the present invention, the content of the conjugated diolefin structural unit may be 20 to 45 mol%, for example, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44 or 45 mol%. Based on the total amount of the ethylene copolymer described in the third aspect of the present invention, the content of the conjugated diolefin structural unit is preferably 25 to 40 mol%. More preferably, based on the total amount of the ethylene copolymer described in the third aspect of the present invention, the content of the conjugated diolefin structural unit is 30 to 35 mol%.

[0075] According to the ethylene copolymer of the third aspect of the present invention, the conjugated diolefin structural unit is a 1,2-polymerized structural unit formed substantially by 1,2-polymerization of a conjugated diolefin. Based on the total amount of the conjugated diolefin units in the ethylene copolymer, the total amount of the 1,2-polymerized structural units is 95 mol% or more, preferably 98 mol% or more, more preferably 100 mol%. According to the ethylene copolymer of the third aspect of the present invention, the double bond content of the main chain of the ethylene copolymer is generally 5 mol% or less, preferably 2 mol% or less, more preferably 0 mol%.

[0076] According to the ethylene copolymer according to the third aspect of the present invention, the 1,2-polymerized structural units include a 1,2-polymerized vinyl structural unit formed by 1,2-polymerization of a conjugated diolefin and having a side chain double bond, a 1,2-cyclopropane ring structural unit formed by 1,2-polymerization of a conjugated diolefin and having a cyclopropane ring, and a 1,5-cyclopentane ring structural unit formed by 1,2-polymerization of a conjugated diolefin and having a cyclopentane ring. Based on the total amount of the ethylene copolymer according to the third aspect of the present invention, the content of the 1,2-polymerized vinyl structural unit may be 18 to 40 mol%, for example, 18, 18.5, 19, 19.5, 20, 20.5, 21, 21.5, 22, 22.5, 23, 23.5, 24, 24.5, 25, 25.5, 26, 26.5, 27, 27.5, 28, 28.5, 29, 29.5, 30, 30.5, 31, 31.5, 32, 32.5, 33, 33.5, 34, 34.5, 35, 35.5, 36, 36.5, 37, 37.5, 38, 38.5, 39, 39.5, or 40 mol%. Preferably, the content of the 1,2-polymerized vinyl structural unit is 20 to 35 mol % based on the total amount of the ethylene copolymer described in the third aspect of the present invention, and more preferably, the content of the 1,2-polymerized vinyl structural unit is 21 to 30 mol % based on the total amount of the ethylene copolymer described in the third aspect of the present invention.

[0077] Based on the total amount of conjugated diolefin structural units in the ethylene copolymer described in the third aspect of the present invention, the content of the 1,2-polymerized vinyl structural units reaches 55% or more, preferably 55 to 90%, for example, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89 or 90%. Based on the total amount of conjugated diolefin structural units in the ethylene copolymer described in the third aspect of the present invention, the content of the 1,2-polymerized vinyl structural units is preferably 60 to 88%. More preferably, based on the total amount of conjugated diolefin structural units in the ethylene copolymer described in the third aspect of the present invention, the content of the 1,2-polymerized vinyl structural units is 63 to 85%.

[0078] According to the ethylene copolymer according to the third aspect of the present invention, in the conjugated diolefin structural units of the copolymer, the molar ratio of 1,2-cyclopentane ring structural units to 1,2-cyclopropane ring structural units is 0.1 to 3:1, preferably 0.3 to 2.5:1, more preferably 0.4 to 2:1, and further preferably 0.5 to 1.8:1.

[0079] The weight average molecular weight (M w ) may be 20,000 to 300,000, but is preferably 25,000 to 250,000, more preferably 30,000 to 200,000, and even more preferably 40,000 to 150,000. According to the ethylene copolymer according to the third aspect of the present invention, the molecular weight distribution index (M w / M n ) is 3.5 or less, preferably 3.2 or less, and more preferably 1.5 to 3.

[0080] According to the ethylene copolymer according to the third aspect of the present invention, the glass transition temperature (T g ) may be in the range of -50°C to -15°C, but is preferably in the range of -40°C to -20°C.

[0081] According to a fourth aspect of the present invention, there is provided a composition comprising an ethylene copolymer and a crosslinking agent, the ethylene copolymer being the ethylene copolymer according to the first or third aspect of the present invention.

[0082] The crosslinking agent may be a material capable of crosslinking the vinyl in the ethylene copolymer. Specifically, the crosslinking agent may be one or more of sulfur, sulfur monochloride, selenium, tellurium, and peroxide. In a preferred embodiment, the crosslinking agent is a peroxide, for example, dicumyl peroxide.

[0083] The composition according to the present invention may contain a vulcanization accelerator to accelerate vulcanization, shorten the vulcanization time, lower the vulcanization temperature, and reduce the amount of vulcanizing agent used. The vulcanization accelerator may be a commonly used substance that can achieve the above functions, such as triallyl isocyanurate. The composition according to the present invention may also contain one or more of other components, such as antioxidants and fillers, according to specific requirements, and a preferred example of the filler may include, but is not limited to, carbon black.

[0084] According to a fifth aspect of the present invention, there is provided a crosslinked polymer obtained by crosslinking the ethylene copolymer according to the first aspect of the present invention or the third aspect of the present invention. The crosslinked polymer according to the fifth aspect of the present invention can be obtained by contacting the ethylene copolymer according to the first aspect of the present invention or the third aspect of the present invention with a crosslinking agent to cause a crosslinking reaction.

[0085] According to a sixth aspect of the present invention, there is provided a tire, at least one component of which contains an ethylene copolymer according to the first aspect of the present invention, a composition according to the fourth aspect of the present invention, or a crosslinked polymer according to the fifth aspect of the present invention.

[0086] The present invention will be described in detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0087] In the following examples and comparative examples, the molecular weight and molecular weight distribution index (M w / M n ) is measured using an Agilent 1260 Infinity II high temperature gel permeation chromatograph, with two MIXD-B columns (300 x 7.5 mm) and one Guard column (50 x 7.5 mm) as the chromatography columns. The mobile phase is trichlorobenzene, the flow rate is 1 mL / min, the concentration of the sample solution is 1 mg / mL, the injection volume is 200 μL, the test temperature is 150 °C, and monodisperse polystyrene is used as the standard sample.

[0088] In the following examples and comparative examples, a commercially available 400 MHz Bruker nuclear magnetic resonance spectroscopic apparatus is used for the nuclear magnetic resonance spectroscopy test, and deuterated o-dichlorobenzene is used as a solvent and tetramethylsilane (TMS) is used as an internal standard for testing the microstructure of the polymer. Here, the term "conjugated diolefin structural unit" refers to a structural unit formed of conjugated diolefin, "1,2-polymerization" refers to the polymerization of conjugated diolefin by 1,2-addition, "1,4-polymerization" refers to the polymerization of conjugated diolefin by 1,4-addition, "1,3-polymerization" refers to the polymerization of conjugated diolefin by 1,3-addition, and "vinyl" refers to a structural unit formed by 1,2-polymerization of conjugated diolefin and having a side chain double bond (using butadiene as an example, vinyl is

[0089] [ka]

[0090] ), and a "cyclopropane ring" is a structural unit having a cyclopropane ring formed by 1,2-polymerization of a conjugated diolefin (for example, butadiene, the cyclopropane ring is

[0091] [ka]

[0092] ), and a "cyclopentane ring" is a structural unit formed by 1,2-polymerization of conjugated diolefins and having a cyclopentane ring (for example, butadiene, the cyclopentane ring is

[0093] [ka]

[0094] ).

[0095] The following examples and comparative examples relate to the following metal compounds and comparative metal compounds:

[0096] [ka] JPEG0007621483000015.jpg222169

[0097] In Production Examples 1 to 4, metal compounds 1 to 4 are produced.

[0098] Manufacturing Example 1 Synthesis of metal compound 1 0.94g (2mmol) of bis(2,5-dimethylcyclopentabithiophene)-dimethylsilane and 50mL of ethyl ether were added to a reaction flask, and 2.5mL (4mmol) of 1.6M butyllithium hexane solution was added dropwise at -78℃. After stirring at room temperature (25℃) for 6 hours, the temperature was lowered to -40℃, and 0.466g (2mmol) of zirconium tetrachloride was slowly added. Stirring was continued overnight. The solid was filtered and washed with ethyl ether. The product was recrystallized from dichloromethane. Yield: 45% by weight. H 1 -NMR (CDCl3, 400 MHz): δppm 6.75 (q, 4H), 2.51 (d, 12H), 1.82 (s, 6H).

[0099] Manufacturing Example 2 Synthesis of metal compound 4 The synthesis was carried out in the same manner as for metal compound 1, except that 2 mmol of bis(cyclopentabithiophene)-dimethylsilane was used instead of bis(2,5-dimethylcyclopentabithiophene)-dimethylsilane. Yield: 57% by weight. H 1 -NMR (CDCl3, 400 MHz): δppm 7.15 (d, 4H), 7.10 (d, 4H), 1.80 (s, 6H).

[0100] Production Example 3 Synthesis of metal compound 2.

[0101] A reaction flask was charged with 1.02 g (2 mmol) of bis(2-methyl-5-n-propyl-3-(9-phenanthrenyl)-6-hydro-cyclopenta[2,3-b]thiophene-6)-dimethylsilane and 50 mL of ethyl ether, and 2.5 mL (4 mmol) of 1.6 M butyllithium hexane solution was added dropwise at -78°C. After stirring at room temperature (25°C) for 6 hours, 0.466 g (2 mmol) of zirconium tetrachloride was slowly added. Stirred overnight. Filtered and the solid was washed with ethyl ether. The filtrate was suction filtered to dryness to obtain the desired product. Yield: 56% by weight. H 1 -NMR (CDCl3, 400 MHz): δppm 7.15-8.90 (m, 18H), 6.62 (s, 2H), 1.15-2.95 (m, 14H), 1.08 (s, 6H), 0.92 (t, 6H).

[0102] Production Example 4 Synthesis of metal compound 3 The same synthesis method as for metal compound 5 was adopted, except that bis(2,5-dimethyl-3-phenyl-6-hydro-cyclopenta[2,3-b]thiophene-6)-dimethylsilane was used instead of bis(2-methyl-5-ethyl-3-(9-phenanthrenyl)-6-hydro-cyclopenta[2,3-b]thiophene-6)-dimethylsilane (2 mmol). Yield: 61% by weight. H 1-NMR (CDCl3, 400 MHz): δppm 7.10-8.85 (m, 18H), 6.60(s, 2H), 1.85-2.80(m, 10H), 1.10(s, 6H), 0.85(s, 6H).

[0103] Examples 1 to 6 illustrate the ethylene polymer and the method for producing the same according to the present invention.

[0104] Example 1 A 500 mL stainless steel reaction vessel was thoroughly purged with nitrogen gas, then with hydrogen gas, and 120 g of toluene, 8 mL of methylaluminoxane (10 wt % toluene solution), and 25.0 g of butadiene were added, followed by addition of 0.44 kg / cm of hydrogen gas. 2 G was added. 7.8 kg / cm at 60°C 2 The liquid and gas phases were saturated with ethylene. Then, 5 μmol of metal compound 1 pre-dissolved in toluene was added to initiate polymerization. Ethylene gas was continuously fed to maintain the total pressure at 7.8 kg / cm. 2 The reaction mixture was kept at 0.5° C. for 15 minutes. After polymerization for 15 minutes, a small amount of methanol was added to stop the reaction. The product was precipitated by pouring it into ethanol containing a large amount of hydrochloric acid (HCl concentration: 2 wt ‰), and the solid was separated by filtration and washed with ethanol. The washed solid was dried in a vacuum oven until no weight loss occurred, thereby obtaining an ethylene copolymer according to the present invention. Specific experimental conditions are shown in Table 1, and test results of property parameters of the produced ethylene copolymer are shown in Table 2.

[0105] Comparative Example 1 An ethylene copolymer was produced in the same manner as in Example 1, except that 2.5 mL of an n-hexane solution of triisobutylaluminum (concentration of triisobutylaluminum was 1 M) was used instead of methylaluminoxane, and a solution of 0.03 mmol of trityltetrakis(pentafluorophenyl)borate in toluene together with metal compound 1 was added to the polymerization reactor. Specific experimental conditions are shown in Table 1, and test results of property parameters of the produced ethylene copolymer are shown in Table 2.

[0106] Comparative Example 2 An ethylene copolymer was prepared in the same manner as in Comparative Example 1, except that metal compound 1 was changed to Comparative Example metal compound 1. Specific experimental conditions are shown in Table 1, and test results of property parameters of the prepared ethylene copolymer are shown in Table 2.

[0107] Comparative Example 3 An ethylene copolymer was prepared in the same manner as in Example 1, except that metal compound 1 was changed to comparative metal compound 1. Specific experimental conditions are shown in Table 1, and test results of property parameters of the prepared ethylene copolymer are shown in Table 2.

[0108] Example 2 An ethylene copolymer was produced in the same manner as in Example 1, except that metal compound 1 was changed to metal compound 2. The property parameters of the produced ethylene copolymer are shown in Table 2.

[0109] Comparative Example 4 An ethylene copolymer was produced in the same manner as in Example 2, except that 2.5 mL of an n-hexane solution of triisobutylaluminum (concentration of triisobutylaluminum was 1 M) was used instead of methylaluminoxane, and a solution of 0.03 mmol of trityltetrakis(pentafluorophenyl)borate in toluene together with metal compound 2 was added to the polymerization reactor. Specific experimental conditions are shown in Table 1, and test results of property parameters of the produced ethylene copolymer are shown in Table 2.

[0110] Comparative Example 5 An ethylene copolymer was prepared in the same manner as in Example 2, except that metal compound 2 was changed to comparative metal compound 2. Specific experimental conditions are shown in Table 1, and the test results of the property parameters of the prepared ethylene copolymer are shown in Table 2.

[0111] Example 3 A 500 mL stainless steel reaction vessel was thoroughly purged with nitrogen gas, then purged with hydrogen gas, and 120 g of toluene, 7.5 mL of MAO (10 wt % toluene solution), and 35 g of butadiene were added, followed by addition of 0.44 kg / cm of hydrogen gas. 2 G is added, and 7.8 kg / cm at 60°C. 2The liquid and gas phases were saturated with ethylene. Polymerization was then initiated using 5 μmol of metal compound 2 pre-dissolved in toluene. Ethylene gas was continuously fed to maintain the total pressure at 7.8 kg / cm. 2 The temperature was kept at 0.5° C. for 15 minutes. After polymerization for 15 minutes, a small amount of methanol was added to stop the reaction. The product was precipitated by pouring it into ethanol containing a large amount of hydrochloric acid (2 wt. ‰, hydrochloric acid is calculated as HCl), and the copolymer was separated by filtration and washed with ethanol. The product was dried in a vacuum oven until the weight did not decrease, to obtain an ethylene copolymer according to the present invention. Specific experimental conditions are shown in Table 1, and test results of property parameters of the produced ethylene copolymer are shown in Table 2.

[0112] Comparative Example 6 An ethylene copolymer was prepared in the same manner as in Example 3, except that metal compound 2 was changed to comparative metal compound 2. Specific experimental conditions are shown in Table 1, and the test results of the property parameters of the prepared ethylene copolymer are shown in Table 2.

[0113] Example 4 An ethylene copolymer was prepared in the same manner as in Example 1, except that metal compound 1 was changed to metal compound 3. Specific experimental conditions are shown in Table 1, and test results of property parameters of the prepared ethylene copolymer are shown in Table 2.

[0114] Comparative Example 7 An ethylene copolymer was produced in the same manner as in Example 3, except that 2.5 mL of an n-hexane solution of triisobutylaluminum (concentration of triisobutylaluminum was 1 M) was used instead of methylaluminoxane, and 0.03 mmol of trityltetrakis(pentafluorophenyl)borate was dissolved in toluene together with metal compound 3 and added to the polymerization reactor. Specific experimental conditions are shown in Table 1, and test results of property parameters of the produced ethylene copolymer are shown in Table 2.

[0115] Comparative Example 8 An ethylene copolymer was prepared in the same manner as in Example 3, except that metal compound 3 was changed to comparative metal compound 3. Specific experimental conditions are shown in Table 1, and test results of property parameters of the prepared ethylene copolymer are shown in Table 2.

[0116] Comparative Example 9 An ethylene copolymer was prepared in the same manner as in Example 3, except that metal compound 3 was changed to comparative metal compound 3. Specific experimental conditions are shown in Table 1, and test results of property parameters of the prepared ethylene copolymer are shown in Table 2.

[0117] Example 5 An ethylene copolymer was prepared in the same manner as in Example 1, except that metal compound 1 was changed to metal compound 4. Specific experimental conditions are shown in Table 1, and test results of property parameters of the prepared ethylene copolymer are shown in Table 2.

[0118] Comparative Example 10 An ethylene copolymer was produced in the same manner as in Example 5, except that 2.5 mL of an n-hexane solution of triisobutylaluminum (concentration of triisobutylaluminum was 1 M) was used instead of methylaluminoxane, and 0.03 mmol of trityltetrakis(pentafluorophenyl)borate was dissolved in toluene together with metal compound 4 and added to the polymerization reactor. Specific experimental conditions are shown in Table 1, and test results of property parameters of the produced ethylene copolymer are shown in Table 2.

[0119] Comparative Example 11 An ethylene copolymer was prepared in the same manner as in Example 5, except that metal compound 4 was changed to comparative metal compound 4. Specific experimental conditions are shown in Table 1, and the test results of the property parameters of the prepared ethylene copolymer are shown in Table 2.

[0120] Example 6 An ethylene copolymer was prepared in the same manner as in Example 1, except that metal compound 1 was changed to metal compound 4. Specific experimental conditions are shown in Table 1, and test results of property parameters of the prepared ethylene copolymer are shown in Table 2.

[0121] Comparative Example 12 An ethylene copolymer was prepared in the same manner as in Example 6, except that metal compound 4 was changed to comparative metal compound 5. Specific experimental conditions are shown in Table 1, and the test results of the property parameters of the prepared ethylene copolymer are shown in Table 2.

[0122] Comparative Example 13 An ethylene copolymer was prepared in the same manner as in Example 6, except that metal compound 4 was changed to comparative metal compound 6. Specific experimental conditions are shown in Table 1, and the test results of the property parameters of the prepared ethylene copolymer are shown in Table 2.

[0123] [Table 1]

[0124] [Table 2]

[0125] The results in Table 2 reveal that the ethylene copolymer according to the present invention has an improved molecular weight and a narrow molecular weight distribution index, as well as an improved content of conjugated diolefin structural units and is almost free of unsaturated groups in the main chain of the ethylene copolymer. The results in Table 2 also reveal that the olefin polymerization method according to the present invention not only produces the ethylene copolymer according to the present invention, but also improves catalytic activity and production efficiency.

[0126] Test Examples 1-2 The ethylene copolymers prepared in Examples 2 and 4 were blended in an open roll with carbon black, peroxide and vulcanization coagent according to the formulations shown in Table 3. The vulcanization properties of the blends were tested at a temperature of 160°C using an MDR vulcanizer purchased from Alpha Technologies to evaluate the vulcanization rate, and the test time was 20 minutes. The test results are shown in Table 4.

[0127] Comparative test examples 1-2 The vulcanization characteristics of the ethylene copolymers produced in Comparative Examples 5 and 9 were tested in the same manner as in Test Examples 1 and 2, and the test results are shown in Table 4.

[0128] [Table 3]

[0129] [Table 4]

[0130] It is clear from the test results of vulcanization properties in Table 4 that the ethylene copolymer of the present invention had a faster torque increase during vulcanization, a faster vulcanization rate, and a higher degree of vulcanization.

[0131] The above detailed description is the preferred embodiment of the present invention, but the present invention is not limited thereto. Within the scope of the technical concept of the present invention, many simple modifications can be made to the technical solution of the present invention, including combining each technical feature in any other suitable manner, and these simple modifications and combinations should also be considered as the contents disclosed in the present invention, and all belong to the patent scope of the present invention.

Claims

1. An ethylene copolymer, An ethylene copolymer comprising an ethylene structural unit derived from ethylene and a conjugated diolefin structural unit derived from a conjugated diolefin, the content of the conjugated diolefin structural unit being 25 to 45 mol % based on the total amount of the ethylene copolymer, the content of 1,2-polymerized vinyl structural units formed by 1,2-polymerization of a conjugated diolefin and having a side chain double bond being 21 to 40 mol %, the total amount of the 1,2-polymerized structural units being 95 mol % or more based on the total amount of conjugated diolefin structural units in the ethylene copolymer, and the weight average molecular weight of the ethylene copolymer being 20,000 to 300,000.

2. 2. The ethylene copolymer according to claim 1, wherein the content of the 1,2-polymerized vinyl structural unit is 21 to 35 mol % based on the total amount of the ethylene copolymer.

3. 3. The ethylene copolymer according to claim 2, wherein the content of the 1,2-polymerized vinyl structural unit is 21 to 30 mol % based on the total amount of the ethylene copolymer.

4. The ethylene copolymer according to any one of claims 1 to 3, wherein the content of the 1,2-polymerized vinyl structural units is 55 to 90% based on the content of the conjugated diolefin structural units.

5. The ethylene copolymer according to claim 4, wherein the content of the 1,2-polymerized vinyl structural units is 63 to 85% based on the content of the conjugated diolefin structural units.

6. The ethylene copolymer according to any one of claims 1 to 5, wherein the total amount of the 1,2-polymerized structural units is 98 mol % or more based on the total amount of conjugated diolefin structural units in the ethylene copolymer.

7. 7. The ethylene copolymer according to claim 6, wherein the total amount of said 1,2-polymerized structural units is 100 mol % based on the total amount of conjugated diolefin structural units in the ethylene copolymer.

8. The ethylene copolymer according to any one of claims 1 to 7, wherein the content of the conjugated diolefin structural unit is 25 to 40 mol % based on the total amount of the ethylene copolymer.

9. The ethylene copolymer according to claim 8, wherein the content of the conjugated diolefin structural unit is 30 to 35 mol % based on the total amount of the ethylene copolymer.

10. 10. The ethylene copolymer according to claim 1, wherein in the conjugated diolefin structural units, the molar ratio of 1,2-cyclopentane ring structural units to 1,2-cyclopropane ring structural units is 0.1 to 3:

1.

11. 11. The ethylene copolymer according to claim 10, wherein in the conjugated diolefin structural units, the molar ratio of 1,2-cyclopentane ring structural units to 1,2-cyclopropane ring structural units is 0.5 to 1.8:

1.

12. The ethylene copolymer according to any one of claims 1 to 11, having a weight average molecular weight of 25,000 to 250,000 and a molecular weight distribution index of 3.5 or less.

13. The ethylene copolymer according to any one of claims 1 to 12, having a glass transition temperature in the range of -50°C to -15°C.

14. The ethylene copolymer according to claim 13, having a glass transition temperature in the range of -40°C to -20°C.

15. The ethylene copolymer according to any one of claims 1 to 14, wherein the conjugated diolefin is butadiene.

16. A method for producing an ethylene copolymer, comprising the step of contacting ethylene with a conjugated diolefin in the presence of a polymerization catalyst containing a component A selected from metal compounds represented by Formula 1 and a component B containing an aluminoxane. 【Chemistry 1】 (In formula 1, M is selected from Group 4 metal atoms; X １ and X ２ are the same or different and each independently represents a halogen atom; Rb is a divalent group containing a Group 14 element, L １ and L ２ are the same or different and are each independently selected from the groups represented by formulas 3 to 6, 【Chemistry 2】 【change】 In formula 3, R Ａ １ , R Ａ ２ , R Ａ ３ , R Ａ ４ and R Ａ ５ are the same or different, and each independently represents a hydrogen atom or C １ -C ２０ is an alkyl group of In formula 4, R Ｂ １ , R Ｂ ２ , R Ｂ ３ , R Ｂ ４ and R Ｂ ５ are the same or different, and each independently represents a hydrogen atom or C １ -C ２０ is an alkyl group of In formula 5, R Ｃ １ , R Ｃ ２ , R Ｃ ３ and R Ｃ ４ are the same or different, and each independently represents a hydrogen atom or C １ -C ２０ is an alkyl group of In formula 6, R Ｄ １ , R Ｄ ２ , R Ｄ ３ and R Ｄ ４ are the same or different, and each independently represents a hydrogen atom or C １ -C ２０ is an alkyl group.)

17. In formula 1, M is a zirconium atom, and / or In formula 1, X １ and X ２ The method of claim 16 , wherein each is independently a chlorine atom.

18. The method according to claim 16 or 17, wherein in formula 1, Rb is a silicon-containing divalent group.

19. The method according to claim 18, wherein in formula 1, Rb is a divalent group represented by formula 2: 【Chemistry 3】 (In formula 2, R １ and R ２ are the same or different, and each independently represents C １ -C １０ is an alkyl group.)

20. The method according to claim 16, wherein the component A is one or more metal compounds selected from the group consisting of metal compounds represented by formulas 7 to 10. 【Chemistry 4】

21. The method according to any one of claims 16 to 20, wherein the molar ratio of component A to component B is 1:0.1 to 5000.

22. The method according to any one of claims 16 to 21, wherein the amount of component A used is 0.1 to 100 µmol per 1 mol of conjugated diolefin.

23. 23. The method of any one of claims 16 to 22, wherein the conjugated diolefin is butadiene.

24. The method according to any one of claims 16 to 23, wherein the contacting is carried out at a temperature of from -50°C to 150°C, and the ethylene pressure is from 0 to 100 MPa in terms of gauge pressure.

25. The method according to any one of claims 16 to 24, wherein the contact is carried out in the presence of a molecular weight regulator, and the weight average molecular weight of the produced ethylene copolymer is 20,000 to 300,000 depending on the amount of the molecular weight regulator used.

26. A composition comprising an ethylene copolymer and a crosslinking agent, the ethylene copolymer being the ethylene copolymer according to any one of claims 1 to 15.

27. A crosslinked polymer obtained by crosslinking the ethylene copolymer according to any one of claims 1 to 15.

28. A tire, at least one component of which comprises the ethylene copolymer of any one of claims 1 to 15, the composition of claim 26, or the crosslinked polymer of claim 27.

Images