Ethylene-isoprene polymers, process for their preparation and vulcanizates

Abstract

The present application relates to the field of synthetic rubber, and discloses an ethylene-isoprene polymer, a preparation method thereof and a vulcanized rubber. The ethylene-isoprene polymer comprises polyethylene segments and polyisoprene segments; the content of the polyethylene segments is 0.1-40 wt% and the content of the polyisoprene segments is 60-99.9 wt% based on the total weight of the ethylene-isoprene polymer; the content of cis-1,4-structure is 80-95 mol% based on the total molar amount of the polyisoprene segments; and the content of toluene insoluble matter is 0.3-6.5 wt% based on the total weight of the ethylene-isoprene polymer. The polyethylene segments in the ethylene-isoprene polymer can modify the polyisoprene segments, avoid the problems such as phase separation and interface failure existing in the direct blending of polyethylene and isoprene rubber in the traditional process, and significantly improve the aging performance of the vulcanized rubber prepared from the ethylene-isoprene polymer.

Description

Technical Field

[0001] The present invention relates to the field of synthetic rubber, in particular to an ethylene-isoprene polymer and a preparation method thereof and a vulcanized rubber. Background Art

[0002] Ethylene, a readily available and abundant monomer, is widely used in the plastics industry. Conjugated dienes, particularly isoprene and isoprene, are the most important monomers for synthetic rubber. However, due to the different polymerization mechanisms of conjugated dienes and α-olefins, copolymerization of the two is difficult. Therefore, the copolymerization of ethylene and conjugated dienes using the same catalytic system is a highly challenging task, and achieving this goal has long been a focus of research and industry.

[0003] Due to its own structure, polyethylene has excellent tensile strength, tear strength, corrosion resistance, electrical insulation, anti-slip properties, low heat generation and aging resistance. These excellent properties of polyethylene can be effectively utilized to improve the properties of rubber, such as improving the aging resistance of polyisoprene rubber products, thereby improving the performance and service life of polyisoprene rubber products.

[0004] However, polyethylene is a plastic, while isoprene rubber is an elastomer. The difference in properties between the two materials leads to poor dispersion in pure mechanical mixing, which fails to achieve the desired goal. Therefore, providing a polyethylene isoprene rubber polymer with good dispersion and a catalytic preparation technology thereof is currently a problem that needs to be solved. Summary of the Invention

[0005] The present invention aims to improve the shortcomings of the prior art polyisoprene rubber materials, namely, poor aging performance, and provides an ethylene-isoprene polymer, a preparation method thereof, and a vulcanized rubber. The ethylene-isoprene polymer comprises polyethylene segments and polyisoprene segments in a block distribution, wherein the polyethylene segments can modify the polyisoprene segments, thereby avoiding the problems of phase separation and interfacial failure that occur when polyethylene and isoprene rubber are directly blended in conventional processes. The polymer also contains a specific amount of toluene insoluble matter, thereby significantly improving the aging performance and mechanical properties of the vulcanized rubber prepared from the ethylene-isoprene polymer.

[0006] To achieve the above objectives, the present invention provides, in a first aspect, an ethylene-isoprene polymer, comprising a polyethylene segment and a polyisoprene segment; based on the total weight of the ethylene-isoprene polymer, the polyethylene segment has a content of 0.1-40 wt%, and the polyisoprene segment has a content of 60-99.9 wt%; in the polyisoprene segment, the cis-1,4 structure has a content of 80-95 mol% based on the total molar amount of the polyisoprene segment;

[0007] The content of toluene insoluble matter is 0.2-7 wt % based on the total weight of the ethylene-isoprene polymer.

[0008] A second aspect of the present invention provides a method for preparing an ethylene-isoprene polymer, the method comprising:

[0009] (1) In the presence of an organic solvent and a catalyst, an aluminum-containing cocatalyst-1 is used to initiate a polymerization reaction of ethylene monomer to obtain a polyethylene product;

[0010] (2) adding isoprene and aluminum-containing co-catalyst-2 to the mixed system obtained in step (1) in sequence to initiate a copolymerization reaction between the isoprene monomer and the polyethylene active chain segment in the polyethylene product to obtain the ethylene-isoprene polymer.

[0011] The third aspect of the present invention provides an ethylene-isoprene polymer prepared by the preparation method of the present invention.

[0012] A fourth aspect of the present invention provides a vulcanized rubber prepared from the ethylene-isoprene polymer of the present invention.

[0013] Through the above technical solution, the ethylene-isoprene polymer and its preparation method and vulcanized rubber provided by the present invention achieve the following beneficial effects:

[0014] The ethylene-isoprene polymer provided by the present invention comprises polyethylene segments and polyisoprene segments distributed in blocks, and contains a specific content of toluene-insoluble matter. The polyethylene segments can modify the polyisoprene segments, thereby avoiding the problems of phase separation and interface failure that occur in the direct blending of polyethylene and isoprene rubber in traditional processes, thereby significantly improving the aging properties of the vulcanized rubber prepared from the ethylene-isoprene polymer.

[0015] The present invention provides a method for preparing an ethylene-isoprene polymer, utilizing a one-step polymerization process in the presence of a catalyst to simultaneously synthesize polyethylene and polyisoprene. The in-situ polymerization yields a polymer comprising polyethylene segments and polyisoprene segments in a block-like distribution, eliminating the need for subsequent compounding or blending to obtain an ethylene-isoprene polymer with excellent compatibility and dispersibility. Furthermore, compared to step-by-step polymerization, the present invention offers advantages such as simple process, strong operability, low cost, and easier adjustment of the polymerization process and composite material composition, making it suitable for industrial production. DETAILED DESCRIPTION

[0016] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0017] A first aspect of the present invention provides an ethylene-isoprene polymer, characterized in that the ethylene-isoprene polymer comprises a polyethylene segment and a polyisoprene segment; based on the total weight of the ethylene-isoprene polymer, the content of the polyethylene segment is 0.1-40 wt%, and the content of the polyisoprene segment is 60-99.9 wt%; in the polyisoprene segment, the content of the cis-1,4-structure is 80-95 mol% based on the total molar amount of the polyisoprene segment;

[0018] The content of toluene insoluble matter is 0.2-7 wt % based on the total weight of the ethylene-isoprene polymer.

[0019] In the present invention, the ethylene-isoprene polymer contains polyethylene segments and polyisoprene segments distributed in blocks. The polyethylene segments can modify the polyisoprene segments, thereby avoiding the problems of phase separation and interface failure that occur when polyethylene and isoprene rubber are directly blended in a traditional process. As a result, the aging properties of the vulcanized rubber prepared from the ethylene-isoprene polymer are significantly improved. In addition, the ethylene-isoprene polymer contains a specific amount of toluene insoluble matter, which can reinforce the vulcanized rubber and further improve the mechanical properties and aging resistance of the vulcanized rubber.

[0020] Furthermore, when the content of the polyethylene segment and the polyisoprene segment in the ethylene-isoprene polymer and the content of the cis-1,4 structure in the polyisoprene segment meet the above ranges, the aging properties of the vulcanizate prepared from the ethylene-isoprene polymer are further improved.

[0021] In the present invention, the toluene insoluble matter refers to the components insoluble in toluene in the ethylene-isoprene polymer when tested according to SH / T 1050-2014.

[0022] In the present invention, the content of toluene insoluble matter in the ethylene-isoprene polymer is measured with reference to SH / T1050-2014.

[0023] In some preferred embodiments of the present invention, preferably, based on the total weight of the ethylene-isoprene polymer, the content of the polyethylene segment is 2-32 wt%, and the content of the isoprene segment is 68-98 wt%.

[0024] In some preferred embodiments of the present invention, preferably, the content of cis-1,4-structure in the isoprene segment is 85-93 mol % based on the total molar amount of the isoprene segment.

[0025] In some preferred embodiments of the present invention, preferably, the content of toluene insoluble matter is 0.3-6.5 wt % based on the total weight of the ethylene-isoprene polymer.

[0026] In the present invention, the contents of polyethylene segments and polyisoprene segments in the ethylene-isoprene polymer, and the content of cis-1,4-structure in the polyisoprene segment are measured by hydrogen nuclear magnetic spectroscopy.

[0027] In some preferred embodiments of the present invention, the number average molecular weight of the ethylene-isoprene polymer is 80,000-800,000, and the molecular weight distribution is 2 to 5. Preferably, the number average molecular weight of the ethylene-isoprene polymer is 100,000-600,000, and the molecular weight distribution is 2.5 to 4.5.

[0028] In the present invention, the number average molecular weight and molecular weight distribution of the ethylene-isoprene polymer are measured by GPC method.

[0029] In some preferred embodiments of the present invention, the total weight of the toluene insoluble matter, wherein the content of polyethylene segments is 85-95 wt %.

[0030] In the present invention, the polyethylene segment content in the toluene insoluble matter is measured by hydrogen nuclear magnetic spectroscopy.

[0031] In the present invention, when the content of the polyethylene segment in the toluene insoluble matter satisfies the above range, it is beneficial to achieve effective compatibility of the polyethylene segment and the isoprene segment in the ethylene-isoprene polymer without phase separation, so that the mechanical properties and aging resistance of the prepared vulcanized rubber are further improved.

[0032] A second aspect of the present invention provides a method for preparing an ethylene-isoprene polymer, the method comprising:

[0033] (1) In the presence of an organic solvent and a catalyst, an aluminum-containing cocatalyst-1 is used to initiate a polymerization reaction of ethylene monomer to obtain a polyethylene product;

[0034] (2) adding isoprene and aluminum-containing co-catalyst-2 to the mixed system obtained in step (1) in sequence to initiate a copolymerization reaction between the isoprene monomer and the polyethylene active chain segment in the polyethylene product to obtain the ethylene-isoprene polymer.

[0035] The present invention provides a method for preparing an ethylene-isoprene polymer. In the presence of a catalyst, a one-step polymerization process is employed to simultaneously synthesize polyethylene and polyisoprene. Furthermore, in situ polymerization is performed to obtain a polymer comprising polyethylene segments and polyisoprene segments in a block distribution. The polyethylene segments and polyisoprene segments in the polymer are chemically bonded together, and a polyethylene-composite polyisoprene rubber with good compatibility and dispersibility can be obtained without the need for subsequent compounding or blending. This significantly improves the performance of the polyisoprene rubber. Furthermore, compared to step-by-step polymerization, the preparation method provided by the present invention has advantages such as simplicity, high operability, low cost, and easier adjustment of the polymerization process and composite material composition, making it advantageous for industrial production.

[0036] Specifically, the preparation method provided by the present invention can obtain the ethylene-isoprene polymer comprising a specific content of polyethylene segments and polyisoprene segments as described in the first aspect of the present invention, and the polyisoprene segments contain a specific content of cis-1,4-structure.

[0037] In a specific embodiment of the present invention, an ethylene polymerization reaction can be performed first, followed by a copolymerization reaction of polyethylene and isoprene monomers. The two reaction processes can be performed continuously. The same catalyst can be used in the polymerization and copolymerization reactions, and different co-catalysts can be used to initiate different monomers, respectively, to achieve the reaction of the different monomers to form the corresponding segments.

[0038] In a specific embodiment of the present invention, preferably, the catalyst is a cobalt-based catalyst containing a cobalt organic compound.

[0039] In one embodiment of the present invention, preferably, in step (1), the catalyst is selected from compounds having structures shown in Formula 1 and / or Formula 2:

[0040]

[0041] wherein X is chlorine or bromine; R1 is H, or a monosubstituted substituent at position 2 or 4 of the benzene ring, or the same or different substituents at positions 2, 4 or 2, 6 of the benzene ring, or the same or different substituents at positions 2, 4, and 6 of the benzene ring, wherein the substituent is -F, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -C6H5, or -CH(C6H5)2;

[0042] R3 is H, or -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -C6H5 or -CH(C6H5)2 which are monosubstituted at the 6-position of the pyridine ring, or -CH3, -N(CH3)2 or -CF3 which are monosubstituted at the 4-position of the pyridine ring, or -CH3, -CH2CH3, -C6H5, -CH(C6H5)2, -N(CH3)2 or -CF3 which are disubstituted at the 4- and 6-positions of the pyridine ring;

[0043] R2 and R4 are each independently hydrogen, or -Cl, -F, -CH3, -OCH3, -N(CH3)2 or -CF3 which is monosubstituted at the 4-position of the pyridine ring.

[0044] In some embodiments of the present invention, R1 represents a substituent on the benzene ring in Formula 1, and multiple substitution positions on the benzene ring are allowed to be all H, preferably R1 is H; or R1 represents that some of the substitution positions on the benzene ring are substituent groups other than H, as described above, monosubstituted at position 2 or 4 on the benzene ring, or disubstituted at positions 2, 4 or 2, 6 on the benzene ring, or trisubstituted at positions 2, 4, and 6 on the benzene ring, and the other substitution positions are H, wherein the substituents may be the same or different in the case of disubstituted and trisubstituted, and preferably, -F, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, - C6H5 or -CH(C6H5)2, or -F, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -C6H5 or -CH(C6H5)2 disubstituted at positions 2, 4 or 2, 6 on the benzene ring, or -F, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -C6H5 or -CH(C6H5)2 trisubstituted at positions 2, 4 or 6 on the benzene ring, more specifically, one of the following groups represented by the substitution position on the benzene ring: 2-F-, 2-CH3-, 4-F-, 4-CH3-, 2,4 -F-、2,4-CH3-、2,6-F-、2,6-CH3-、2,4,6-F-、2,4,6-CH3-、2-CH2CH3-、4-CH2CH3-、2,4-CH2CH3-、2-CH2CH3-4-CH3-、2,6-C H2CH3-, 2-CH2CH3-6-CH3-, 2,4,6-CH2CH3-, 2-CH(CH3)2-, 4-CH(CH3)2-, 2,4-CH(CH3)2-, 2,6-CH(CH3)2-, 2,4,6-CH(CH3) In the present invention, the number in front of the substituent refers to the substitution position on the benzene ring. For example, 2-F- refers to -F substituted at the 2nd position on the benzene ring.

[0045] In some embodiments of the present application, R3 represents a substituent on the pyridine ring (other than the pyridine ring substituted by R4) in Formula 2, allowing all of the substitutable positions on the pyridine ring to be H, preferably R3 is H; or R3 represents a substituent on the pyridine ring other than H, such as a single substituent on the 4- or 6-position of the pyridine ring, as previously described, or a double substituent on the 4, 6-positions of the pyridine ring, wherein the substituents can be the same or different, preferably -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -C6H5, or -CH(C6H5)2 in the case of a single substituent on the 6-position of the pyridine ring, or -CH3, -N(CH3)2, or -CF3 in the case of a single substituent on the 4-position of the pyridine ring, or -CH3, -CH2CH3, -C6H5, -CH(C6H5)2, -N(CH3)2, or -CF3 in the case of a double substituent on the 4, 6-positions of the pyridine ring, more particularly one of the following groups: 6-CH3-, 6-CH2CH3-, 6-C6H5-, 6-CH(C6H5)2-, 4-CH3-, 4-N(CH3)2-, 4-CF3-, 4,6-CH3-, 4-CH3-6-CH2CH3-, 4-CH3-6-C6H5-, 4-CH3-6-CH(C6H5)2-, 4-N(CH3)2-6-CH3-, 4-N(CH3)2-6-CH2CH3-, 4-N(CH3)2-6-C6H5-, 4-N(CH3)2-6-CH(C6H5)2-, 4-CF3-6-CH3-, 4-CF3-6-CH2CH3-, 4-CF3-6-C6H5-, 4-CF3-6-CH(C6H5)2-. In the present application, the number preceding the substituent refers to the position of the substituent on the pyridine ring, for example, 6-CH3- means -CH3 is substituted on the 6-position of the pyridine ring.

[0046] In some embodiments of the present application, R2 and R4 each independently represent a substituent on the pyridine ring in Formula 1, 2, allowing all of the substitutable positions on the pyridine ring to be H, preferably R2 and R4 are each H; or R2 and R4 each represent a substituent on the pyridine ring other than H, more particularly -Cl, -F, -CH3, -OCH3, -N(CH3)2, or -CF3 in the case of a single substituent on the 4-position of the pyridine ring, preferably one of the following groups: 4-Cl-, 4-F-, 4-CH3-, 4-OCH3-, 4-N(CH3)2-, 4-CF3-. R2 and R4 can be the same or different. In the present application, the number preceding the substituent refers to the position of the substituent on the pyridine ring, for example, 4-Cl- means -Cl is substituted on the 4-position of the pyridine ring.

[0047] In some embodiments of the present invention, preferably, the aluminum-containing cocatalyst-1 is selected from at least one of methylaluminoxane (MAO), triisobutylaluminum-modified methylaluminoxane (MMAO), diethylaluminum chloride, ethylaluminum sesquichloride, di-n-propylaluminum chloride, diisopropylaluminum chloride, di-n-butylaluminum chloride, diisobutylaluminum chloride, di-n-octylaluminum chloride, ethylaluminum dichloride, n-propylaluminum dichloride, isopropylaluminum dichloride, n-butylaluminum dichloride, isobutylaluminum dichloride, and n-octylaluminum dichloride, and is preferably selected from at least one of methylaluminoxane, triisobutylaluminum-modified methylaluminoxane, diisobutylaluminum chloride, diethylaluminum chloride, and ethylaluminum sesquichloride. In the present invention, under the combined action of the catalyst and the aluminum-containing cocatalyst-1, the polymerization reaction of ethylene monomer is initiated.

[0048] In some embodiments of the present invention, preferably, the aluminum-containing co-catalyst-2 is selected from at least one of diethylaluminum chloride, ethylaluminum sesquichloride, di-n-propylaluminum chloride, diisopropylaluminum chloride, di-n-butylaluminum chloride, diisobutylaluminum chloride, di-n-octylaluminum chloride, ethylaluminum dichloride, n-propylaluminum dichloride, isopropylaluminum dichloride, n-butylaluminum dichloride, isobutylaluminum dichloride, and n-octylaluminum dichloride, preferably at least one of diisobutylaluminum chloride, diethylaluminum chloride, and ethylaluminum sesquichloride. In the present invention, under the combined action of the catalyst and the aluminum-containing co-catalyst-2, a copolymerization reaction of isoprene monomer and polyethylene is initiated.

[0049] In some embodiments of the present invention, preferably, the molar ratio of the catalyst: the aluminum-containing co-catalyst-1: the aluminum-containing co-catalyst-2 is 1:20-1000:20-1000, preferably 1:50-900:50-900. In the present invention, when the molar ratio of the catalyst, the aluminum-containing co-catalyst-1, and the aluminum-containing co-catalyst-2 is controlled to meet the above range, the reaction activities of the polymerization reaction and the copolymerization reaction in steps (1) and (2) can be controlled, thereby achieving control of the content of the polyethylene segment and the polyisoprene segment in the ethylene-isoprene polymer, as well as the content of the cis-1,4-structure in the polyisoprene segment.

[0050] In some embodiments of the present invention, the amount of the catalyst used is 0.3-16 mmol, preferably 0.4-12 mmol, relative to 1 mol of ethylene. In the present invention, controlling the amount of catalyst to ethylene to meet the above range can control the ethylene polymerization activity and achieve regulation of the ethylene segment content of the polymer.

[0051] In some embodiments of the present invention, preferably, in step (1), the polymerization reaction temperature is 20-70°C, preferably 30-60°C; the polymerization reaction pressure is 1-70 bar, preferably 3-40 bar; and the polymerization reaction time is 1-80 min, preferably 2-60 min. In the present invention, the polymerization reaction pressure in step (1) can be the gas phase pressure of the fed ethylene monomer.

[0052] In some embodiments of the present invention, preferably, the organic solvent is selected from at least one of n-pentane, neopentane, n-hexane, cyclohexane, n-heptane, n-octane, isooctane, benzene, toluene, decahydronaphthalene, dodecane and hydrogenated gasoline, preferably toluene.

[0053] In some embodiments of the present invention, preferably, in step (2), the concentration of the isoprene-containing organic solution is 0.4-8 mol / L, preferably 0.6-6 mol / L. In the present invention, there is no particular limitation on the amount of the organic solvent used, as long as the concentration of the isoprene-containing organic solution in step (2) meets the above range.

[0054] In some embodiments of the present invention, preferably, the copolymerization reaction temperature is 30-70°C, preferably 40-60°C; the copolymerization reaction pressure is 1-10 bar, preferably 2-5 bar; and the copolymerization reaction time is 1-7 hours, preferably 2-6 hours. In the present invention, the copolymerization reaction pressure in step (2) can be the gas phase pressure of the isoprene monomer fed.

[0055] In some embodiments of the present invention, the amount relationship between the ethylene monomer and the isoprene can be controlled by the time and pressure at which the ethylene monomer is introduced into the polymerization reaction, thereby obtaining the ethylene-isoprene polymer of the present invention. Preferably, the weight relationship between the ethylene monomer and the isoprene monomer satisfies the amounts of the corresponding polyethylene segments and polyisoprene rubber segments in the obtained ethylene-isoprene polymer, for example, based on the total weight of the ethylene-isoprene polymer, the content of the polyethylene segment is 0.1-40wt%, preferably 2-32wt%, and the content of the polyisoprene segment is 60-99.9wt%, preferably 68-98wt%; based on the total molar amount of the polyisoprene segment, the content of the cis-1,4-structure is 80-95mol%, preferably 85-93mol%.

[0056] In the present invention, when the copolymerization reaction needs to be terminated, the following steps may also be performed:

[0057] When the copolymerization reaction reaches a suitable time, a stabilizer and a terminator are added in sequence to terminate the copolymerization reaction, and then the obtained product is washed and vacuum dried to obtain the ethylene-isoprene polymer.

[0058] In the present invention, the stabilizer can be an agent that acts as an antioxidant, and can be a toluene solution of 2,2-methylenebis-(4-methyl-6-tert-butylphenol) with a mass concentration of 5%, and can be added in an amount of 0.5wt%-1wt% of the total weight of the monomer. The terminator can be an agent that acts to terminate polymerization and remove residual catalyst, and can be a methanol solution with a mass concentration of 4%, and can be added in an amount of 0.1wt%-1wt% of the total weight of the monomer. The washing process can be performed by sequentially using a methanol solution and water for approximately three times.

[0059] In one embodiment of the present invention, the method for preparing the ethylene-isoprene polymer comprises the following steps:

[0060] The polymerization reaction environment of the reaction apparatus is purified using a double-row pipe operation technique; the cobalt-based catalyst and an organic solvent provided by the present invention are added to the reaction apparatus, stirred and dispersed uniformly, and heated to a set temperature; ethylene monomer is then introduced into the reaction apparatus at a pressure of 1-70 bar, and after maintaining a constant pressure, a set amount of aluminum-containing cocatalyst-1 is added to initiate ethylene polymerization. The polymerization reaction time is determined based on the content of polyethylene segments in the resulting ethylene-isoprene polymer;

[0061] After the set polymerization reaction time is reached, the introduction of ethylene monomer is stopped, and purified isoprene monomer is added. Aluminum-containing co-catalyst-2 is added to initiate the copolymerization reaction of isoprene monomer and polyethylene active chain segments, and the constant pressure is maintained for the set time;

[0062] Finally, a stabilizer and a terminator were added to terminate the reaction; the obtained product was washed three times with a methanol solution and then vacuum dried to obtain the ethylene-isoprene polymer.

[0063] The third aspect of the present invention provides an ethylene-isoprene polymer prepared by the preparation method of the present invention.

[0064] In the present invention, the ethylene-isoprene polymer is as described in the first aspect of the present invention, and will not be described in detail here.

[0065] A fourth aspect of the present invention provides a vulcanized rubber prepared from the ethylene-isoprene polymer of the present invention.

[0066] The present invention will be described in detail below through examples. In the following examples, the polyethylene segment content in the ethylene-isoprene polymer, the polyisoprene segment content, the cis-1,4 structure content in the polyisoprene segment, and the polyethylene segment content in the toluene insoluble matter were measured by H-NMR spectroscopy.

[0067] The number average molecular weight and molecular weight distribution of the ethylene-isoprene polymer were measured by GPC.

[0068] The toluene-insoluble content is determined according to SH / T 1050-2014: Thin strips of the polymer sample are cut at multiple points, weighed to approximately 0.3 g (accurate to 0.1 mg), and spread evenly onto a constant-weight filter to prevent the strip from sticking. Approximately 100 mL of toluene is added to a weighing bottle, and the filter is suspended in the bottle. Secure the bottle cap and allow the solution to dissolve on a shaker at room temperature for 48 hours. Remove the filter, rinse several times, vacuum dry, and weigh.

[0069] The raw materials used in the examples and comparative examples are all commercially available products.

[0070] Example 1

[0071] (1) The polymerization reaction equipment was circulated three times using a double-row pipe operation technique, and then 2 L of toluene and the catalyst shown in Formula 1 (wherein R1 is 2,6-CH(CH3)2- (other substitution positions on the benzene ring are hydrogen), R2 is H (all substitution positions on the pyridine ring are hydrogen), and X is chlorine) (2.260 mmol) were added. The mixed system was quickly stirred by mechanical stirring to uniformly disperse the system; the uniformly dispersed mixed system was heated to 30° C., ethylene monomer was introduced to maintain a constant pressure (7 bar) atmosphere, and methylaluminoxane (MAO) (0.679 mol) was added to initiate ethylene polymerization. After 10 minutes of polymerization, the introduction of ethylene monomer was stopped;

[0072] 300 g (4.41 mol) of isoprene was added, and a constant pressure (3 bar) atmosphere was maintained. Diisobutylaluminum chloride (0.679 mol) was injected to initiate the copolymerization reaction of isoprene and polyethylene. The copolymerization reaction temperature was 45° C., and the copolymerization reaction time was 3 h.

[0073] A 5% toluene solution of 2,2-methylenebis(4-methyl-6-tert-butylphenol) was then added as a stabilizer. 20 mL of a 4% hydrochloric acid methanol solution was then added to the polymerization system to terminate the reaction. Finally, the polymer product was washed three times with methanol and dried in vacuo to obtain 302.5 g of ethylene-isoprene polymer A1.

[0074] (2) The obtained ethylene-isoprene polymer was characterized by H NMR spectrum (ppm) (chemical shift of 5.24 for the polyisoprene segment peak and 1.10 for the polyethylene segment peak); the polyethylene segment content was 10.7 wt%, the polyisoprene rubber segment content was 89.3 wt%; the cis-1,4-structure content in the polyisoprene rubber segment was 90.4 mol%;

[0075] According to GPC test data, the number average molecular weight of the ethylene-isoprene polymer is 229,000 and the molecular weight distribution is 3.43.

[0076] According to the toluene insoluble matter test data, the toluene insoluble matter content in the ethylene-isoprene polymer is 1.4 wt %. Based on the total weight of the toluene insoluble matter, the content of the polyethylene segment is 91.5 wt %.

[0077] Example 2

[0078] (1) The polymerization reaction equipment was circulated three times using a double-row tube operation technique, and then 2 L of toluene and a catalyst as shown in Formula 1 (wherein R1 is 2,6-CH(CH3)2- (other substitution positions on the benzene ring are hydrogen), R2 is 4-OCH3- (while other substitution positions on the pyridine ring are hydrogen), and X is chlorine) (2.260 mmol) were added. The mixed system was quickly stirred by mechanical stirring to uniformly disperse the mixed system; the uniformly dispersed mixed system was heated to 37° C., ethylene monomer was introduced to maintain a constant pressure (5 bar) atmosphere, and then methylaluminoxane (MAO) (1.36 mol) was added to initiate ethylene polymerization. After 5 minutes of polymerization, the introduction of ethylene monomer was stopped;

[0079] 400 g (5.88 mol) of isoprene was added, and a constant pressure (2 bar) atmosphere was maintained. Diisobutylaluminum chloride (0.679 mol) was injected to initiate the isoprene copolymerization reaction. The copolymerization reaction temperature was 48° C., and the copolymerization reaction time was 4 h.

[0080] The polymerization product was post-treated according to the method of Example 1 to obtain 366.2 g of ethylene-isoprene polymer A2.

[0081] (2) The obtained ethylene-isoprene polymer was characterized by H NMR spectrum (ppm) (chemical shift of 5.24 for the polyisoprene segment peak and 1.10 for the polyethylene segment peak); the polyethylene segment content was 2.8 wt%, the polyisoprene segment content was 97.2 wt%; the cis-1,4-structure content in the polyisoprene rubber segment was 92.6 mol%;

[0082] According to GPC test data, the number average molecular weight of the ethylene-isoprene polymer is 294,000 and the molecular weight distribution is 2.82.

[0083] According to toluene insoluble matter test data, the toluene insoluble matter content in the ethylene-isoprene polymer is 0.4 wt %. Based on the total weight of the toluene insoluble matter, the content of the polyethylene segment is 94.6 wt %.

[0084] Example 3

[0085] (1) The polymerization reaction equipment was circulated three times using a double-row tube operation technique, and then 3 L of toluene and a catalyst as shown in Formula 1 (wherein R1 is 2,6-F- (other substitution positions on the benzene ring are hydrogen), R2 is 4-CF3- (while other substitution positions on the pyridine ring are hydrogen), and X is chlorine) (2.260 mmol) were added, and the mixed system was uniformly dispersed by rapid stirring using a mechanical stirrer; the uniformly dispersed mixed system was heated to 40° C., ethylene monomer was introduced while maintaining a constant pressure (15 bar) atmosphere, and triisobutylaluminum-modified methylaluminoxane (MMAO) (0.904 mol) was added to initiate ethylene polymerization, and the introduction of ethylene monomer was stopped after 12 minutes of polymerization;

[0086] 630 g (9.26 mol) of isoprene was added, and a constant pressure (2.5 bar) atmosphere was maintained. Diisobutylaluminum chloride (0.679 mol) was injected to initiate the isoprene copolymerization reaction. The copolymerization reaction temperature was 50° C., and the copolymerization reaction time was 4.5 h.

[0087] The polymerization product was post-treated according to the method of Example 1 to obtain 660.2 g of ethylene-isoprene polymer A3.

[0088] (2) The obtained ethylene-isoprene polymer was characterized by H NMR spectrum (ppm) (chemical shift of 5.24 for the polyisoprene segment peak and 1.10 for the polyethylene segment peak); the polyethylene segment content was 13.7 wt%, the polyisoprene segment content was 86.3 wt%; the cis-1,4-structure content in the polyisoprene rubber segment was 89.6 mol%;

[0089] According to GPC test data, the number average molecular weight of the ethylene-isoprene polymer is 521,000 and the molecular weight distribution is 3.68.

[0090] According to toluene insoluble matter test data, the toluene insoluble matter content in the ethylene-isoprene polymer is 2.5 wt %. Based on the total weight of the toluene insoluble matter, the content of the polyethylene segment is 90.7 wt %.

[0091] Example 4

[0092] (1) The polymerization reaction equipment was circulated three times using a double-row tube operation technique, and then 2 L of toluene and a catalyst as shown in Formula 1 (wherein R1 is 2,6-CH2CH3- (other substitution positions on the benzene ring are hydrogen), R2 is 4-N(CH3)2- (while other substitution positions on the pyridine ring are hydrogen), and X is bromine) (2.260 mmol) were added. The mixed system was uniformly dispersed by rapid stirring using a mechanical stirrer; the uniformly dispersed mixed system was heated to 33° C., ethylene monomer was introduced while maintaining a constant pressure (6 bar) atmosphere, and methylaluminoxane (MAO) (1.584 mol) was added to initiate ethylene polymerization, and the reaction time was 18 min; the introduction of ethylene monomer was stopped;

[0093] Isoprene 280 g (4.12 mol) was added, a constant pressure (3 bar) atmosphere was maintained, and diisobutyl aluminum chloride (0.158 mol) was injected to initiate the isoprene copolymerization reaction. The copolymerization temperature was 53°C, and the copolymerization time was 3.5 h.

[0094] The polymerization product was post-treated according to the method of Example 1 to obtain ethylene-isoprene polymer A4 301.7 g.

[0095] (2) The obtained ethylene-isoprene polymer was characterized: nuclear magnetic hydrogen spectrum (ppm) (polyisoprene segment peak at 5.24, polyethylene segment peak at 1.10); the content of polyethylene segment was 15.9 wt%, and the content of polyisoprene segment was 84.1 wt%; in the polyisoprene rubber segment, the content of cis-1,4 structure was 88.9 mol%;

[0096] The GPC test data showed that the number average molecular weight of the ethylene-isoprene polymer was 237,000, and the molecular weight distribution was 3.82.

[0097] The toluene insoluble test data showed that the toluene insoluble content of the ethylene-isoprene polymer was 2.4 wt%, and the content of polyethylene segment was 90.1 wt% based on the total weight of the toluene insoluble.

[0098] Example 5

[0099] (1) The polymerization equipment was circulated three times using double-pipe operation technology, 2 L of toluene and a catalyst as shown in Formula 1 (wherein R1 is 2-C(CH3)3-6-CH3- (the other substitution sites on the benzene ring are hydrogen), R2 is 4-Cl- (at the same time, the other substitution sites on the pyridine ring are hydrogen), and X is bromine) (2.260 mmol) were added, and the mixed system was uniformly dispersed using mechanical stirring. The uniformly dispersed mixed system was heated to 35°C, ethylene monomer was introduced to maintain a constant pressure (5 bar) atmosphere, and diethyl aluminum chloride (0.452 mol) was added to initiate ethylene polymerization. The reaction time was 60 min, and then the introduction of ethylene monomer was stopped.

[0100] Isoprene 450 g (6.62 mol) was added, a constant pressure (2.2 bar) atmosphere was maintained, and diisobutyl aluminum chloride (2.036 mol) was injected to initiate the isoprene copolymerization reaction. The copolymerization temperature was 54°C, and the copolymerization time was 3.2 h.

[0101] The polymerization product was post-treated according to the method of Example 1 to obtain ethylene-isoprene polymer A5 437.8 g.

[0102] (2) The obtained ethylene-isoprene polymer was characterized by H NMR spectrum (ppm) (chemical shift of 5.24 for the polyisoprene segment peak and 1.10 for the polyethylene segment peak); the polyethylene segment content was 5.9 wt%, the polyisoprene segment content was 94.1 wt%; the cis-1,4-structure content in the polyisoprene rubber segment was 92.2 mol%;

[0103] According to GPC test data, the number average molecular weight of the ethylene-isoprene polymer is 344,000 and the molecular weight distribution is 3.07.

[0104] According to toluene insoluble matter test data, the toluene insoluble matter content in the ethylene-isoprene polymer is 0.8 wt %. Based on the total weight of the toluene insoluble matter, the content of the polyethylene segment is 93.1 wt %.

[0105] Example 6

[0106] (1) The polymerization reaction equipment was circulated three times using a double-row tube operation technique, and then 2 L of toluene and a catalyst as shown in Formula 2 (wherein, R3 is 4,6-CH3- (the other substitution positions on the pyridine ring substituted by R3 are hydrogen), R4 is hydrogen (the substitution positions on the pyridine ring substituted by R4 are all hydrogen), and X is chlorine) (2.260 mmol) were added. The mixed system was quickly stirred by mechanical stirring to uniformly disperse the mixed system; the uniformly dispersed mixed system was heated to 48° C., ethylene monomer was introduced to maintain a constant pressure (30 bar) atmosphere, and di-tert-butylaluminum chloride (0.226 mol) was added to initiate ethylene polymerization. The reaction time was 15 min, and then the introduction of ethylene monomer was stopped;

[0107] 300 g (4.41 mol) of isoprene was added, and a constant pressure (3.5 bar) atmosphere was maintained. Diethylaluminum chloride (1.584 mol) was injected to initiate the isoprene copolymerization reaction. The copolymerization reaction temperature was 58° C., and the copolymerization reaction time was 3.2 h.

[0108] The polymerization product was post-treated according to the method of Example 1 to obtain 395.0 g of ethylene-isoprene polymer A6.

[0109] (2) The obtained ethylene-isoprene polymer was characterized by H NMR spectrum (ppm) (chemical shift of 5.24 for the polyisoprene segment peak and 1.10 for the polyethylene segment peak); the polyethylene segment content was 31.6 wt %, the polyisoprene segment content was 68.4 wt %; the cis-1,4 structure content in the polyisoprene rubber segment was 85.4 mol %;

[0110] According to GPC test data, the number average molecular weight of the ethylene-isoprene polymer is 313,000 and the molecular weight distribution is 4.47.

[0111] According to toluene insoluble matter test data, the toluene insoluble matter content in the ethylene-isoprene polymer is 6.3 wt %. Based on the total weight of the toluene insoluble matter, the content of the polyethylene segment is 85.7 wt %.

[0112] Example 7

[0113] (1) The polymerization reaction equipment was circulated three times using a double-row tube operation technique, and then 2 L of toluene and a catalyst as shown in Formula 2 (wherein, R3 is 4-N(CH3)2-6-CH2CH3- (the other substitution position on the pyridine ring substituted by R3 is hydrogen), R4 is 4-OCH3- (while the other substitution position on the pyridine ring substituted by R4 is hydrogen), and X is bromine) (2.260 mmol) were added. The mixed system was quickly stirred with a mechanical stirrer to uniformly disperse the mixed system; the uniformly dispersed mixed system was heated to 50° C., ethylene monomer was introduced to maintain a constant pressure (8 bar) atmosphere, and diethylaluminum chloride (0.684 mol) was added to initiate ethylene polymerization. The reaction time was 16 min, and then the introduction of ethylene monomer was stopped;

[0114] 470 g (6.91 mol) of isoprene was added, and a constant pressure (3.5 bar) atmosphere was maintained. Ethylaluminum sesquihydrate (0.684 mol) was injected to initiate the copolymerization of isoprene monomer. The copolymerization temperature was 60° C., and the copolymerization time was 3.8 h.

[0115] The polymerization product was post-treated according to the method of Example 1 to obtain 544 g of ethylene-isoprene polymer A7.

[0116] (2) The obtained ethylene-isoprene polymer was characterized by H NMR spectrum (ppm) (chemical shift of polyisoprene segment peak at 5.24, polyethylene segment peak at 1.10); polyethylene segment content was 22.8 wt%, polyisoprene rubber segment content was 77.2 wt%; the content of cis-1,4-structure in the polyisoprene rubber segment was 87.5 mol%;

[0117] According to GPC test data, the number average molecular weight of the ethylene-isoprene polymer is 434,000 and the molecular weight distribution is 4.17.

[0118] According to toluene insoluble matter test data, the toluene insoluble matter content in the ethylene-isoprene polymer is 5.7 wt %. Based on the total weight of the toluene insoluble matter, the content of the polyethylene segment is 88.2 wt %.

[0119] Example 8

[0120] (1) The polymerization reaction equipment was circulated three times using a double-row tube operation technique, and then 2 L of toluene and a catalyst as shown in Formula 2 (wherein, R3 is 4-CF3-6-C6H5- (other substitution positions on the pyridine ring substituted by R3 are hydrogen), R4 is hydrogen (and other substitution positions on the pyridine ring substituted by R4 are hydrogen), and X is chlorine) (2.260 mmol) were added. The mixed system was uniformly dispersed by rapid stirring using a mechanical stirrer; the uniformly dispersed mixed system was heated to 55° C., ethylene monomer was introduced while maintaining a constant pressure (24 bar) atmosphere, and methylaluminoxane (MAO) (1.584 mol) was added to initiate ethylene polymerization. After 25 minutes of polymerization, the introduction of ethylene monomer was stopped;

[0121] 580 g (8.53 mol) of isoprene was added, and a constant pressure (2.5 bar) atmosphere was maintained. Diisoethylaluminum chloride (1.584 mol) was injected to initiate a continuous copolymerization reaction of isoprene. The copolymerization reaction temperature was 55° C., and the copolymerization reaction time was 2.8 h.

[0122] The polymerization product was post-treated according to the method of Example 1 to obtain 660 g of ethylene-isoprene polymer A8.

[0123] (2) The obtained ethylene-isoprene polymer was characterized by H NMR spectrum (ppm) (chemical shift of polyisoprene peak at 5.24, polyethylene segment peak at 1.10); polyethylene segment content was 19.7 wt%, polyisoprene segment content was 80.3 wt%; the content of cis-1,4-structure in the polyisoprene rubber segment was 87.9 mol%;

[0124] According to GPC test data, the number average molecular weight of the ethylene-isoprene polymer is 515,000 and the molecular weight distribution is 4.02.

[0125] According to toluene insoluble matter test data, the toluene insoluble matter content in the ethylene-isoprene polymer is 5.9 wt %. Based on the total weight of the toluene insoluble matter, the content of the polyethylene segment is 89.4 wt %.

[0126] Example 9

[0127] (1) The polymerization reaction equipment was circulated three times using a double-row tube operation technique, and then 1 L of toluene and the catalyst shown in Formula 2 (wherein, R3 is 6-CH(C6H5)2- (the other substitution position on the pyridine ring substituted by R3 is hydrogen), R4 is 4-Cl (while the other substitution position on the pyridine ring substituted by R4 is hydrogen), and X is chlorine) (2.260 mmol) were added. The mixed system was quickly stirred with a mechanical stirrer to uniformly disperse the mixed system; the uniformly dispersed mixed system was heated to 42° C., ethylene monomer was introduced to maintain a constant pressure (4 bar) atmosphere, and methylaluminoxane (MAO) (0.226 mol) was added to initiate ethylene polymerization, and the reaction time was 4 min; the introduction of ethylene monomer was stopped;

[0128] 150 g (2.21 mol) of isoprene was added, and a constant pressure (3 bar) atmosphere was maintained. Diethylaluminum chloride (0.452 mol) was injected to initiate the copolymerization of isoprene monomer. The copolymerization temperature was 50° C., and the copolymerization time was 4.2 h.

[0129] The polymerization product was post-treated according to the method of Example 1 and vacuum dried to obtain 141.2 g of ethylene-isoprene polymer A9.

[0130] (2) The obtained ethylene-isoprene polymer was characterized by H NMR spectrum (ppm) (chemical shift of polyisoprene segment peak at 5.24, polyethylene segment peak at 1.10); polyethylene segment content was 4.4 wt%, polyisoprene rubber segment content was 95.6 wt%; the content of cis-1,4-structure in the polyisoprene rubber segment was 92.3 mol%;

[0131] According to GPC test data, the number average molecular weight of the ethylene-isoprene polymer is 112,000 and the molecular weight distribution is 2.89.

[0132] According to toluene insoluble matter test data, the toluene insoluble matter content in the ethylene-isoprene polymer is 0.5 wt %. Based on the total weight of the toluene insoluble matter, the content of the polyethylene segment is 93.6 wt %.

[0133] Example 10

[0134] (1) The polymerization reaction equipment was circulated three times using a double-row tube operation technique, and then 2 L of toluene and a catalyst as shown in Formula 1 (wherein R1 is 2,6-CH3- (other substituents on the benzene ring are hydrogen), R2 is H (all substituents on the pyridine ring are hydrogen), and X is chlorine) (2.260 mmol) were added. The mixed system was quickly stirred by mechanical stirring to uniformly disperse the system; the uniformly dispersed mixed system was heated to 38° C., ethylene monomer was introduced to maintain a constant pressure (12 bar) atmosphere, and methylaluminoxane (MAO) (0.113 mol) was added to initiate ethylene polymerization. The reaction time was 30 min, and then the introduction of ethylene monomer was stopped;

[0135] 190 g (2.79 mol) of isoprene was added, and a constant pressure (2.8 bar) atmosphere was maintained. Diisobutylaluminum chloride (1.131 mol) was injected to initiate the isoprene copolymerization reaction. The copolymerization reaction temperature was 45° C., and the copolymerization reaction time was 2.4 h.

[0136] The polymerization product was post-treated according to the method of Example 1 to obtain 10223.5 g of ethylene-isoprene polymer A.

[0137] (2) The obtained ethylene-isoprene polymer was characterized by H NMR spectrum (ppm) (chemical shift of polyisoprene segment peak at 5.24, polyethylene segment peak at 1.10); the polyethylene segment content was 27.5 wt%, the polyisoprene rubber segment content was 72.5 wt%; the cis-1,4-structure content in the polyisoprene rubber segment was 86.3 mol%;

[0138] According to GPC test data, the number average molecular weight of the ethylene-isoprene polymer is 187,000 and the molecular weight distribution is 4.32.

[0139] According to toluene insoluble matter test data, the toluene insoluble matter content in the ethylene-isoprene polymer is 4.1 wt %. Based on the total weight of the toluene insoluble matter, the content of the polyethylene segment is 87.6 wt %.

[0140] Example 11

[0141] (1) The polymerization reaction equipment was circulated three times using a double-row tube operation technique, and then 2 L of toluene and the catalyst shown in Formula 1 (wherein R1 is 2,6-CH2CH3- (other substituents on the benzene ring are hydrogen), R2 is H (all substituents on the pyridine ring are hydrogen), and X is bromine) (2.260 mmol) were added. The mixed system was quickly stirred by mechanical stirring to uniformly disperse the mixed system; the uniformly dispersed mixed system was heated to 45° C., ethylene monomer was introduced to maintain a constant pressure (10 bar) atmosphere, and methylaluminoxane (MAO) (1.034 mol) was added to initiate ethylene polymerization. The reaction time was 3 minutes, and then the introduction of ethylene monomer was stopped;

[0142] 470 g (6.91 mol) of isoprene was added, and a constant pressure (4 bar) atmosphere was maintained. Diisobutylaluminum chloride (0.226 mol) was injected to initiate the isoprene copolymerization reaction. The copolymerization reaction temperature was 43° C., and the copolymerization reaction time was 3 h.

[0143] The polymerization product was post-treated according to the method of Example 1 to obtain 1460.5 g of ethylene-isoprene polymer A1.

[0144] (2) The obtained ethylene-isoprene polymer was characterized by H NMR spectrum (ppm) (chemical shift of 5.24 for the polyisoprene segment peak and 1.10 for the polyethylene segment peak); the polyethylene segment content was 8.8 wt%, the polyisoprene segment content was 91.2 wt%; the cis-1,4-structure content in the polyisoprene rubber segment was 91.2 mol%;

[0145] According to GPC test data, the number average molecular weight of the ethylene-isoprene polymer is 367,000 and the distribution is 3.22.

[0146] According to toluene insoluble matter test data, the toluene insoluble matter content in the ethylene-isoprene polymer is 1.3 wt %. Based on the total weight of the toluene insoluble matter, the content of the polyethylene segment is 92.3 wt %.

[0147] Comparative Example 1

[0148] (1) The polymerization reaction equipment was circulated three times using a double-row tube operation technique, and then 2 L of toluene and the catalyst shown in Formula 1 (wherein, R1 = 2,4,6-CH3- (other substituents on the benzene ring are hydrogen), R2 is H (all substituents on the pyridine ring are hydrogen), and X is bromine) (2.260 mmol) were added. The mixed system was quickly stirred with a mechanical stirrer to uniformly disperse the mixed system; the uniformly dispersed mixed system was heated to 70°C, 220 g (3.24 mol) of isoprene was added, and a constant pressure (3 bar) atmosphere was maintained. Diisobutylaluminum chloride (1.584 mol) was injected to initiate the polymerization of the isoprene monomer. The reaction time was 4 h.

[0149] The polymerization product was post-treated according to the method of Example 1 to obtain 192.7 g of polyisoprene rubber D1.

[0150] (2) The obtained polyisoprene rubber was characterized by H NMR spectrum (ppm) (polyisoprene rubber peak with a chemical shift of 5.24); the content of cis-1,4-structure was 95.2 mol%.

[0151] According to GPC test data, the number average molecular weight of the isoprene rubber is 157,000 and the distribution is 2.75.

[0152] No toluene insoluble matter.

[0153] Comparative Example 2

[0154] The polyisoprene rubber and polyethylene prepared in Comparative Example 1 were solution blended to prepare 164.6 g of a blend D2 of polyethylene and polyisoprene rubber, wherein the polyethylene content was 5.9 wt % based on the total weight of the blend.

[0155] According to the toluene insoluble matter test data, the toluene insoluble matter content in the blend is 5.9 wt %. Based on the total weight of the toluene insoluble matter, the content of the polyethylene segment is 100 wt %.

[0156] Comparative Example 3

[0157] The polyisoprene rubber and polyethylene prepared in Comparative Example 1 were solution blended to prepare 180.2 g of a blend D3 of polyethylene and polyisoprene rubber, wherein the content of polyethylene was 10.7 wt % based on the total weight of the blend.

[0158] According to the toluene insoluble matter test data, the toluene insoluble matter content in the blend is 10.7 wt %, of which the polyethylene segment content is 100 wt %.

[0159] Comparative Example 4

[0160] (1) The polymerization reaction equipment was circulated three times using a double-row pipe operation technique, and then 2 L of toluene and the catalyst shown in Formula 1 (wherein R1 is 2,6-CH(CH3)2- (other substitution positions on the benzene ring are hydrogen), R2 is H (all substitution positions on the pyridine ring are hydrogen), and X is chlorine) (2.260 mmol) were added, and the mixed system was uniformly dispersed by rapid stirring using a mechanical stirrer; the uniformly dispersed mixed system was heated to 30° C., ethylene monomer was introduced while maintaining a constant pressure (30 bar) atmosphere, and methylaluminoxane (MAO) (0.679 mol) was added to initiate ethylene polymerization. After 30 minutes of polymerization, the introduction of ethylene monomer was stopped;

[0161] 300 g (4.41 mol) of isoprene was added, and a constant pressure (3 bar) atmosphere was maintained. Diisobutylaluminum chloride (0.679 mol) was injected to initiate the copolymerization reaction of isoprene and polyethylene. The copolymerization reaction temperature was 45° C., and the copolymerization reaction time was 3 h.

[0162] The polymerization product was post-treated according to the method of Example 1 to obtain 512.3 g of ethylene-isoprene polymer D4.

[0163] (2) The obtained ethylene-isoprene polymer was characterized by H NMR spectrum (ppm) (chemical shift of 5.24 for the polyisoprene segment peak and 1.10 for the polyethylene segment peak); the polyethylene segment content was 47.3 wt%, the polyisoprene rubber segment content was 52.7 wt%; the cis-1,4-structure content in the polyisoprene rubber segment was 79.7 mol%;

[0164] According to GPC test data, the number average molecular weight of the ethylene-isoprene polymer is 400,000 and the molecular weight distribution is 4.86.

[0165] According to toluene insoluble matter test data, the content of toluene insoluble matter in the ethylene-isoprene polymer was 16.6 wt %. Based on the total weight of the toluene insoluble matter, the content of polyethylene segments was 84.6 wt %.

[0166] Comparative Example 5

[0167] (1) The polymerization reaction equipment was circulated three times using a double-row pipe operation technique, and then 2 L of toluene and the catalyst shown in Formula 1 (wherein R1 is 2,6-CH(CH3)2- (other substitution positions on the benzene ring are hydrogen), R2 is H (all substitution positions on the pyridine ring are hydrogen), and X is chlorine) (2.260 mmol) were added. The mixed system was uniformly dispersed by rapid stirring using a mechanical stirrer; 300 g (4.41 mol) of isoprene was added, and after the ethylene monomer was introduced to maintain a constant pressure (10 bar) atmosphere, diisobutylaluminum chloride (0.679 mol) and methylaluminoxane (MAO) (0.679 mol) were injected to initiate the copolymerization reaction of isoprene and ethylene. The copolymerization reaction temperature was 45°C, and the introduction of the ethylene monomer was stopped after 30 minutes. The copolymerization reaction time was 3 hours;

[0168] The polymerization product was post-treated according to the method of Example 1 to obtain 383.0 g of ethylene-isoprene polymer D5.

[0169] (2) The obtained ethylene-isoprene polymer was characterized by H NMR spectrum (ppm) (chemical shift of 5.24 for the polyisoprene segment peak and 1.10 for the polyethylene segment peak); the polyethylene segment content was 30 wt%, the polyisoprene rubber segment content was 70 wt%; the cis-1,4-structure content in the polyisoprene rubber segment was 72.3 mol%;

[0170] According to GPC test data, the number average molecular weight of the ethylene-isoprene polymer is 85,000 and the molecular weight distribution is 4.59.

[0171] According to toluene insoluble matter test data, the toluene insoluble matter content in the ethylene-isoprene polymer is 0.2 wt %. Based on the total weight of the toluene insoluble matter, the polyethylene segment content is 90.2 wt %.

[0172] Comparative Example 6

[0173] 200 g of the ethylene-isoprene polymer obtained in Example 8 was added to approximately 2 L of toluene and stirred at room temperature for 48 hours until no solids were evident. The mixture was filtered through a 125-μm stainless steel mesh. The filtrate was washed three times with methanol and then dried under vacuum to yield 188.3 g of ethylene-isoprene polymer D6.

[0174] The obtained ethylene-isoprene polymer was characterized by H NMR (ppm) (chemical shift of 5.24 for the polyisoprene segment peak and 1.10 for the polyethylene segment peak); the polyethylene segment content was 15.2 wt %, the polyisoprene segment content was 84.8 wt %; the cis-1,4 structure content in the polyisoprene rubber segment was 87.9 mol %.

[0175] According to GPC test data, the number average molecular weight of the ethylene-isoprene polymer is 522,000 and the molecular weight distribution is 3.94.

[0176] No toluene insoluble matter.

[0177] Comparative Example 7

[0178] 300 mL of a toluene solution containing 17.0 g (0.25 mol) of isoprene was added to a thoroughly dried 400 mL pressure-resistant glass reactor, and ethylene was then introduced at 0.4 MPa. Simultaneously, in a glove box under a nitrogen atmosphere, 18.0 μmol of bis(2-phenylindenyl)gadolinium bis(dimethylsilylamide) [(2-PhC9H6)2GdN(SiHMe2)2], 36.0 μmol of dimethylanilinium tetrakis(pentafluorophenyl)borate (Me2NHPhB(C6F5)4), and 0.90 mmol of diisobutylaluminum hydride were removed from a glass container and dissolved in 10 mL of toluene to obtain a catalyst solution. The catalyst solution was then removed from the glove box, and 17.5 μmol of the catalyst solution, calculated as gadolinium, was added to the monomer solution, which was then polymerized at room temperature for 180 minutes. After polymerization, the polymerization product was post-treated according to the method of Example 1 to obtain 14.2 g of copolymer D7.

[0179] The obtained ethylene-isoprene polymer was characterized by H NMR (ppm) (chemical shift of 5.24 for the polyisoprene segment peak and 1.10 for the polyethylene segment peak); the polyethylene segment content was 12.3 wt%, the polyisoprene rubber segment content was 87.7 wt%; and the cis-1,4 structure content in the polyisoprene rubber segment was 83.5 mol%.

[0180] According to GPC test data, the number average molecular weight of the ethylene-isoprene polymer is 177,000 and the molecular weight distribution is 4.26.

[0181] According to toluene insoluble matter test data, the toluene insoluble matter content in the ethylene-isoprene polymer is 0.1 wt %. Based on the total weight of the toluene insoluble matter, the content of the polyethylene segment is 81.6 wt %.

[0182] As can be seen from the Examples and Comparative Examples, the ethylene-isoprene polymers described herein show a decreasing trend in the cis-1,4 structure content of the isoprene segments as the polyethylene segment content increases, leading to a broader molecular weight distribution. Furthermore, the polymers prepared in Examples 1-11 were prepared by in-situ polymerization, and the toluene-insoluble content of the resulting polymers ranged from 0.4 to 6.3 wt%.

[0183] In Comparative Example 4, when the polyethylene segment content in the resulting polymer exceeded 40 wt%, the cis-1,4 structure content of the isoprene segments decreased to below 80%. In Comparative Example 5, when a one-step polymerization method was used, the cis-1,4 structure content of the isoprene segments in the resulting polymer was further reduced, and the number average molecular weight of the resulting polymer decreased to below 100,000.

[0184] Comparative Example 1 contained no toluene-insoluble matter. Comparative Examples 2-3 employed physical mixing to add toluene-insoluble polyethylene. The polymer of Comparative Example 4 contained a high toluene-insoluble matter content, while the polymer of Comparative Example 5 contained a low toluene-insoluble matter content. Comparative Example 6, after filtration through a stainless steel mesh, contained a lower polyethylene segment content than Example 8 and contained no toluene-insoluble matter. The polymer of Comparative Example 7 contained a low toluene-insoluble matter content.

[0185] Test Case

[0186] Mixing and vulcanization: The ethylene-isoprene polymers prepared in Examples 1-11, and the polyisoprene rubber, the blend of polyethylene and polyisoprene, and the ethylene-isoprene polymer provided in the comparative examples were prepared into vulcanized rubber samples by the following methods:

[0187] Mixing process: All vulcanized rubber formulations were mixed in a Hapro RM-200A torque rheometer (Harbin Hapro Electrical Technology Co., Ltd.). The mixed samples were passed through a two-roll mill 20 times to obtain the final rubber mix. The mixing process is shown in Table 1.

[0188] Preparation of vulcanized rubber samples: After the obtained rubber mix was allowed to stand at room temperature for 24 hours, it was placed in a processing template and vulcanized in an XLB-D350×350 flat plate vulcanizer with the vulcanization temperature set at 150°C and the vulcanization time set at t90.

[0189] Table 1

[0190] Adding time (min) Additives and fillers (weight) 0-1 Polymer, 100 parts 1-2 ZnO, 4 parts; stearic acid, 1.5 parts 2-3 Antioxidant 4010NA, 1 part 3-6 N330, 50 copies 6-7 Accelerator CZ, 1 part; Accelerator D, 0.5 part 7-13 Mixing 13-14 Sulfur S, 1.5 parts 14-15 Discharging

[0191] The prepared vulcanized rubber samples were tested for breaking strength according to GB / T 528-1998. The breaking strength change rate was tested according to GB / T 3512-2001. The aging conditions were 100° C. for 48 hours. The results are shown in Table 2.

[0192] Table 2

[0193]

[0194]

[0195] The results in Table 2 and comparison with the comparative examples show that the vulcanized rubbers prepared from the ethylene-isoprene polymers of Examples 1-11 exhibit higher breaking strength than the vulcanized rubber prepared from polyisoprene rubber alone in Comparative Example 1. Furthermore, after 48 hours of thermal oxidative aging at 100°C, the breaking strength shows a smaller change rate, indicating better aging resistance. This aging resistance improves with increasing polyethylene content. Compared to Comparative Examples 2 and 3, which physically blend polyethylene with isoprene rubber, the vulcanized rubbers obtained from the in-situ polymerization of polyethylene segments with isoprene segments using the one-step polymerization method provided by the present invention to form ethylene-isoprene polymers exhibit superior breaking strength and aging resistance. The polymer of Comparative Example 4, with its high ethylene segment content, exhibits better aging resistance but reduced breaking strength. The polymer of Comparative Example 5, with its low molecular weight, exhibits better aging resistance but reduced breaking strength. In Comparative Example 6, after the toluene-insoluble matter removal process, the mechanical properties of the resulting polymer vulcanizate decreased, becoming lower than those of Example 8 and Examples 3 and 1, which had even lower polyethylene segment contents. This demonstrates that toluene-insoluble matter has a good reinforcing effect on the vulcanizate, improving its mechanical properties and aging resistance. In Comparative Example 7, although the polyethylene segment content of the ethylene-isoprene polymer is higher than that of Examples 1 and 11, the lower toluene-insoluble matter content in Comparative Example 7 results in the vulcanizate's fracture strength and aging properties being inferior to those of Examples 1 and 11.

[0196] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. An ethylene-isoprene polymer, characterized in that The ethylene-isoprene polymer comprises polyethylene segments and polyisoprene segments; based on the total weight of the ethylene-isoprene polymer, the content of the polyethylene segments is 0.1-40 wt%, and the content of the polyisoprene segments is 60-99.9 wt%; in the polyisoprene segments, the content of cis-1,4-structures is 80-95 mol% based on the total molar weight of the polyisoprene segments; The content of toluene insoluble matter is 0.2-7 wt % based on the total weight of the ethylene-isoprene polymer.

2. The ethylene-isoprene polymer according to claim 1, wherein Based on the total weight of the ethylene-isoprene polymer, the content of the polyethylene segment is 2-32 wt %, and the content of the isoprene segment is 68-98 wt %.

3. The ethylene-isoprene polymer according to claim 1 or 2, wherein In the polyisoprene segment, the content of cis-1,4-structure is 85-93 mol % based on the total molar amount of the polyisoprene segment.

4. The ethylene-isoprene polymer according to claim 1 or 2, wherein The number average molecular weight of the ethylene-isoprene polymer is 80,000-800,000, and the molecular weight distribution is 2-5.

5. The ethylene-isoprene polymer according to claim 4, wherein The number average molecular weight of the ethylene-isoprene polymer is 100,000-600,000, and the molecular weight distribution is 2.5-4.

5.

6. The ethylene-isoprene polymer according to claim 1 or 2, wherein The content of toluene insoluble matter is 0.3-6.5 wt % based on the total weight of the ethylene-isoprene polymer.

7. The ethylene-isoprene polymer according to claim 1 or 2, wherein Based on the total weight of the toluene insoluble matter, the content of the polyethylene segment is 85-95 wt %.

8. A method for preparing the ethylene-isoprene polymer according to any one of claims 1 to 7, the method comprising: (1) In the presence of an organic solvent and a catalyst, the polymerization reaction of ethylene monomer is initiated by aluminum-containing cocatalyst-1 to obtain a polyethylene product; (2) adding an organic solution containing isoprene and an aluminum-containing co-catalyst-2 to the mixed system obtained in step (1) in sequence to initiate a copolymerization reaction between the isoprene monomer and the polyethylene active chain segment in the polyethylene product to obtain the ethylene-isoprene polymer.

9. The preparation method according to claim 8, wherein In step (1), the catalyst is a cobalt-containing organic compound.

10. The preparation method according to claim 8 or 9, wherein The catalyst is selected from compounds having the structure shown in Formula 1 and / or Formula 2: Formula 1 Formula 2 wherein X is chlorine or bromine; R1 is H, or a monosubstituted substituent at position 2 or 4 of the benzene ring, or the same or different substituents at positions 2, 4 or 2, 6 of the benzene ring, or the same or different substituents at positions 2, 4, and 6 of the benzene ring, wherein the substituent is -F, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -C6H5, or -CH(C6H5)2; R3 is H, or -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -C6H5 or -CH(C6H5)2 which are monosubstituted at the 6-position of the pyridine ring, or -CH3, -N(CH3)2 or -CF3 which are monosubstituted at the 4-position of the pyridine ring, or -CH3, -CH2CH3, -C6H5, -CH(C6H5)2, -N(CH3)2 or -CF3 which are disubstituted at the 4- and 6-positions of the pyridine ring; R2 and R4 are each independently hydrogen, or -Cl, -F, -CH3, -OCH3, -N(CH3)2 or -CF3 which is monosubstituted at the 4-position of the pyridine ring.

11. The preparation method according to claim 8 or 9, wherein The aluminum-containing cocatalyst-1 is selected from at least one of methylaluminoxane, triisobutylaluminum-modified methylaluminoxane, diethylaluminum chloride, sesquiethylaluminum, di-n-propylaluminum chloride, diisopropylaluminum chloride, di-n-butylaluminum chloride, diisobutylaluminum chloride, di-n-octylaluminum chloride, ethylaluminum dichloride, n-propylaluminum dichloride, isopropylaluminum dichloride, n-butylaluminum dichloride, isobutylaluminum dichloride and n-octylaluminum dichloride.

12. The preparation method according to claim 11, wherein The aluminum-containing cocatalyst-1 is at least one selected from methylaluminoxane, triisobutylaluminum-modified methylaluminoxane, diisobutylaluminum chloride, diethylaluminum chloride and sesquiethylaluminum.

13. The preparation method according to claim 8 or 9, wherein The aluminum-containing co-catalyst-2 is selected from at least one of diethylaluminum chloride, sesquiethylaluminum, di-n-propylaluminum chloride, diisopropylaluminum chloride, di-n-butylaluminum chloride, diisobutylaluminum chloride, di-n-octylaluminum chloride, ethylaluminum dichloride, n-propylaluminum dichloride, isopropylaluminum dichloride, n-butylaluminum dichloride, isobutylaluminum dichloride and n-octylaluminum dichloride.

14. The preparation method according to claim 13, wherein The aluminum-containing co-catalyst-2 is selected from at least one of diisobutylaluminum chloride, diethylaluminum chloride and sesquiethylaluminum.

15. The preparation method according to claim 8 or 9, wherein The molar ratio of the catalyst, the aluminum-containing co-catalyst-1 and the aluminum-containing co-catalyst-2 is 1:20-1000:20-1000; And / or, relative to 1 mol of ethylene, the amount of the catalyst used is 0.3-16 mmol.

16. The preparation method according to claim 15, wherein The molar ratio of the catalyst, the aluminum-containing co-catalyst-1 and the aluminum-containing co-catalyst-2 is 1:50-900:50-900; And / or, relative to 1 mol of ethylene, the amount of the catalyst used is 0.4-12 mmol.

17. The preparation method according to claim 8 or 9, wherein In step (1), the polymerization reaction temperature is 20-70°C; the polymerization reaction pressure is 1-70 bar; and the polymerization reaction time is 1-80 min. And / or, the organic solvent is at least one selected from n-pentane, neopentane, n-hexane, cyclohexane, n-heptane, n-octane, isooctane, benzene, toluene, decahydronaphthalene, dodecane and hydrogenated gasoline.

18. The preparation method according to claim 17, wherein In step (1), the polymerization reaction temperature is 30-60°C; the polymerization reaction pressure is 3-40 bar; and the polymerization reaction time is 2-60 min. And / or, the organic solvent is toluene.

19. The preparation method according to claim 8 or 9, wherein In step (2), the concentration of the isoprene-containing organic solution is 0.4-8 mol / L; And / or, the copolymerization reaction temperature is 30-70° C.; the copolymerization reaction pressure is 1-10 bar; and the copolymerization reaction time is 1-7 h.

20. The preparation method according to claim 19, wherein In step (2), the concentration of the isoprene-containing organic solution is 0.6-6 mol / L; And / or, the copolymerization reaction temperature is 40-60° C.; the copolymerization reaction pressure is 2-5 bar; and the copolymerization reaction time is 2-5 h.

21. An ethylene-isoprene polymer obtained by the preparation method according to any one of claims 8 to 20.

22. A vulcanized rubber prepared from the ethylene-isoprene polymer according to any one of claims 1 to 7 and 21.

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