A high melting point and high toughness vinyl composite elastomer prepared based on a double alpha-diimine nickel catalytic system and a preparation method thereof

Abstract

The present application relates to the technical fields of olefin coordination polymerization and polyolefin thermoplastic elastomer material, in particular to a high-melting-point and high-toughness ethylene-based composite elastomer prepared based on a double alpha-diimine nickel catalyst system and a preparation method thereof.The method comprises the following steps: in the presence of a chain shuttling agent, ethylene is subjected to chain shuttling polymerization reaction under the action of a mixed alpha-diimine nickel catalyst; the mixed alpha-diimine nickel catalyst comprises a mixture of a high-branching soft segment alpha-diimine nickel catalyst and a low-branching hard segment alpha-diimine nickel catalyst in a molar ratio of 9:1 to 1:9.The present application adopts two alpha-diimine nickel catalysts with different chain walking abilities, uses ethylene as the only monomer, and constructs an ethylene-based composite elastomer containing hard segment and soft segment structures in the presence of a chain shuttling agent, so as to obtain a composite polyolefin elastomer material with high melting point, good elastic performance and excellent processing performance.

Description

Technical Field

[0001] This invention relates to the field of olefin coordination polymerization and polyolefin thermoplastic elastomer materials, and in particular to a high-melting-point, high-toughness vinyl composite elastomer prepared based on a bis-α-diimine nickel catalytic system and its preparation method. Background Technology

[0002] Polyolefin materials are among the most widely used polymer materials, possessing advantages such as abundant raw material sources, low density, good chemical corrosion resistance, and ease of processing and molding. They are widely used in packaging, pipes, automobiles, electronics, films, foam materials, and elastomer products. With the development of high-end manufacturing and green sustainable materials, traditional general-purpose polyolefins such as polyethylene and polypropylene can no longer simultaneously meet the comprehensive performance requirements of high strength, high heat resistance, high elasticity, and ease of processing. Therefore, developing novel polyolefin elastomer materials with tunable microstructure and excellent comprehensive properties is of great significance.

[0003] Olefin block copolymers are a class of thermoplastic elastomers composed of crystalline hard segments and amorphous or low-crystallinity soft segments. Compared to traditional random ethylene / α-olefin copolymers, olefin block copolymers can provide physical crosslinking points and heat resistance through hard segments, while the soft segments impart flexibility and elastic recovery properties. Therefore, they have broad application prospects in hot melt adhesives, films, foamed materials, footwear materials, automotive parts, and elastic materials. Currently, olefin block copolymers are typically prepared by chain shuttle polymerization and living polymerization. Among them, chain shuttle polymerization can utilize the reversible chain transfer process between different catalyst active centers and chain shuttles in the same reaction system to achieve the exchange of polymer chains between different active centers, thereby forming polyolefin materials with multi-block structures. This method has advantages such as relatively simple reaction process, high polymerization efficiency, and controllable block structure, making it an important technical route for the preparation of olefin block copolymers.

[0004] However, existing systems for preparing olefin block copolymers mostly rely on copolymerization of ethylene and α-olefins, adjusting the comonomer insertion rate to form crystalline hard segments and low-crystallinity soft segments. These methods typically require the introduction of additional high-carbon-number α-olefin comonomers such as 1-octene and 1-hexene, resulting in high raw material costs, limited comonomer utilization, and complex compositional control. Therefore, there is an urgent need for a new catalytic system and material design method for preparing high-performance polyolefin block elastomers from a single ethylene monomer. Summary of the Invention

[0005] Based on the above, this invention provides a high-melting-point, high-toughness vinyl composite elastomer prepared based on a bis-α-diimine nickel catalytic system and its preparation method.

[0006] To achieve the above objectives, the present invention provides the following solution: One of the technical solutions of this invention is a method for preparing high-melting-point, high-toughness vinyl composite elastomers based on a bis-α-diimine nickel catalytic system, comprising the following steps: In the presence of a chain shuttle agent, ethylene is subjected to chain shuttle polymerization under the action of a mixed α-diimine nickel catalyst; The mixed α-diimide nickel catalyst comprises a highly branched soft-segment α-diimide nickel catalyst and a low-branched hard-segment α-diimide nickel catalyst; the molar ratio of the highly branched soft-segment α-diimide nickel catalyst to the low-branched hard-segment α-diimide nickel catalyst is 9:1 to 1:9. More preferably, the molar ratio of the highly branched soft-segment α-diimide nickel catalyst to the low-branched hard-segment α-diimide nickel catalyst in the mixed α-diimide nickel catalyst is 1:1, 2:1, 3:1, 4:1, 5:1, or any value between the aforementioned two ratios.

[0007] In a preferred embodiment of the present invention, the general structural formula of the highly branched soft-segment α-diimine nickel catalyst is shown in Formula (I); the general structural formula of the low-branched hard-segment α-diimine nickel catalyst is shown in Formula (II). Equation (I); Formula (II); In equation (Ⅰ), when R1 = Me, R2 = H, Me, Et or Ph, and R3 = H, Me, Et. i Pr、 t Bu or OMe; when R1 = Acenaphthyl, R2 = H, Me, Et or Ph, R3 = H, Me, Et, i Pr、 t Bu or OMe; when R1=H, R2=H, Me, Et or Ph, R3= H, Me, Et, i Pr、 t Bu or OMe; when R1 = Ph, R2 = H, Me, Et or Ph, R3 = H, Me, Et, i Pr、 t Bu or OMe; X is Me, Cl, or Br; In equation (II), when R1 = Me, R2 = H, Me, Et, t Bu, OMe, or Ph, R3 = H, Me, Et, i Pr、 t Bu or OMe; when R1 = Acenaphthyl, R2 = H, Me, Et, t Bu, OMe, or Ph, R3 = H, Me, Et, i Pr、 t Bu or OMe; when R1=H, R2=H, Me, Et,t Bu, OMe, or Ph, R3 = H, Me, Et, i Pr、 t Bu or OMe; when R1 = Ph, R2 = H, Me, Et, t Bu, OMe, or Ph, R3 = H, Me, Et, i Pr、 t Bu or OMe; X is Me, Cl or Br.

[0008] In a preferred embodiment of the present invention, the chain shuttle is diethylzinc; the amount of the chain shuttle added is 5 to 500 times (preferably 100 to 500 times) the amount of the mixed α-diimine nickel catalyst.

[0009] In a preferred embodiment of the present invention, the chain shuttle polymerization reaction is carried out under an ethylene atmosphere, with an ethylene pressure of 1~10 atm, a polymerization temperature of 25~120 ℃, and a polymerization time of 1~60 min.

[0010] In a preferred embodiment of the present invention, a co-catalyst is also added to the reaction system.

[0011] In a preferred embodiment of the present invention, the co-catalyst is one or more of methylaluminoxane, a mixture of triisobutylaluminum and tris(pentafluorophenyl)borane, a mixture of triisobutylaluminum and triphenylcarbazo(pentafluorophenyl)borate, and modified methylaluminoxane; the molar ratio of the co-catalyst to the mixed α-diimine nickel catalyst is 2000:1 to 100:1.

[0012] In a preferred embodiment of the present invention, after the chain shuttle polymerization reaction is completed, the process further includes quenching, precipitation, and drying steps.

[0013] The drying temperature is 60-80℃, and the drying time is 6-8 hours.

[0014] The quenching agent used is an acidified ethanol solution, and the acid used as the quenching agent is one or more of hydrochloric acid, sulfuric acid, phosphoric acid, and formic acid. The volume fraction of the acid in the acidified ethanol solution is 10%.

[0015] The reaction system uses an inert organic solvent; the inert organic solvent is one or more of straight-chain hydrocarbons, cyclic hydrocarbons, and aromatic hydrocarbons. Preferably, the solvent is toluene.

[0016] This invention is the first to synthesize vinyl olefin block copolymers using two α-diimine nickel catalysts with different chain-walking capabilities. In a polymerization system, the two catalysts, combined with a co-catalyst and a chain transfer agent, undergo chain shuttle polymerization to synthesize a vinyl olefin block copolymer with alternating soft / hard segments, consisting of highly branched polyethylene as soft segments and low-branched crystalline polyethylene as hard segments.

[0017] The second technical solution of the present invention is a vinyl composite elastomer prepared by the above-mentioned method for preparing high-melting-point and high-toughness vinyl composite elastomers based on the double α-diimine nickel catalytic system.

[0018] The third technical solution of the present invention is the application of the above-mentioned vinyl composite elastomer in the preparation of packaging, pipes, automobiles, electronic appliances, medical devices, films and foam materials.

[0019] The aforementioned vinyl composite elastomers can be applied to high heat-resistant elastomers, recyclable thermoplastic elastomers, films, foamed materials, automotive parts, and flexible products.

[0020] This invention employs two α-diimine nickel catalysts with different chain-walking capabilities, using ethylene as the sole monomer, and constructs a vinyl composite elastomer containing hard and soft segments in the presence of a chain shuttle, thereby obtaining a composite polyolefin elastomer material with both high melting point, good elastic properties, and excellent processing performance.

[0021] Compared with the prior art, the present invention has the following beneficial effects: This invention utilizes α-diimine nickel catalysts with varying chain-walking capabilities during the polymerization process to prepare vinyl composite elastomers via chain shuttle polymerization. By adjusting the content of soft and hard segments, materials with superior performance can be obtained. The continuous polymerization process enables one-pot preparation of high-melting-point, high-toughness vinyl composite elastomers, showing broad prospects for industrial applications.

[0022] The vinyl composite elastomer prepared by the method of this invention has excellent temperature resistance and elasticity, high fracture strength, adjustable elongation at break within a certain range, and significantly enhanced toughness. The preparation method is simple and convenient, and it has great application prospects for polymer modification and expanding application fields. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 The GPC curve of the vinyl composite elastomer obtained in Example 1 of this invention; Figure 2 The GPC curve of the vinyl composite elastomer obtained in Example 2 of this invention; Figure 3 The GPC curve of the vinyl composite elastomer obtained in Example 3 of this invention; Figure 4 The GPC curve of the vinyl composite elastomer obtained in Example 4 of this invention; Figure 5 The GPC curve of the vinyl composite elastomer obtained in Example 5 of this invention; Figure 6 The GPC curve of the vinyl composite elastomer obtained in Example 6 of this invention; Figure 7 The differential scanning calorimeter (DSC) secondary heating curves of the vinyl composite elastomers prepared in Examples 1-6 of this invention are shown below. Figure 8 The stress-strain curves of the vinyl composite elastomers prepared in Examples 3-5 and Comparative Examples 1-2 of this invention are shown below. Figure 9 The image shows the carbon NMR spectrum of the vinyl composite elastomer prepared in Example 1 of this invention. Detailed Implementation

[0025] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0026] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0027] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0028] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0029] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0030] Nickel diimine catalysts are a typical class of post-transition metal olefin polymerization catalysts, exhibiting unique chain-walking polymerization characteristics. Unlike traditional pre-transition metal catalysts, which primarily produce linear polyethylene, nickel diimine catalysts can achieve chain walking during ethylene polymerization through β-hydrogen elimination and re-insertion processes, thereby generating polyethylene structures with varying degrees of branching without the addition of α-olefin comonomers. By altering the steric hindrance, electronic effects, and reaction conditions of the nickel diimine catalyst, the chain walking rate, branching density, molecular weight, and polymer crystallinity can be controlled. Therefore, the α-diimine nickel catalytic system offers new possibilities for preparing structurally tunable high-melting-point vinyl olefin block copolymers from a single ethylene monomer. While α-diimine nickel catalysts have been extensively studied in the preparation of vinyl elastomers, research on the direct construction of high-melting-point vinyl olefin block copolymer elastomers via chain shuttle polymerization using two α-diimine nickel catalysts with different chain-walking capabilities remains limited. In particular, the core challenge in preparing such materials lies in how to enable one catalyst to primarily form highly crystalline, high-melting-point polyethylene hard segments, while the other catalyst forms low-crystalline or amorphous branched polyethylene soft segments, and how to achieve chain transfer between different segments through a chain shuttle agent. Furthermore, nickel catalysts, as post-transition metal catalysts, exhibit superior tolerance to polar monomers, holding promise for preparing high-melting-point vinyl olefin block copolymers with polar functional groups, thus improving the dyeability of these materials.

[0031] Based on this, this invention proposes a dual α-diimine nickel catalytic system. By selecting two diimine nickel catalysts with different chain-walking capabilities and combining them with a chain shuttle agent, reversible chain transfer is achieved during ethylene polymerization. This allows polymer chains to shuttle and grow between different nickel active sites, thereby constructing vinyl olefin block copolymers containing crystalline hard segments and flexible soft segments in the same polymerization system. This method eliminates the need for adding α-olefin comonomers, utilizing ethylene to generate polyethylene segments with different degrees of branching in situ, achieving synergistic control of the material's melting point, crystallinity, elasticity, and processing properties.

[0032] Compared with existing technologies, the double nickel chain shuttle system has lower shuttle efficiency, and the chain growth rate is greater than the chain transfer rate. The resulting polymers often have higher molecular weights and wider molecular weight distributions. The resulting polymers are composite elastomers of block copolymers and mixtures, and the block copolymers can effectively improve the compatibility of the mixtures. The vinyl composite elastomer prepared by this invention has advantages such as high melting point, good elastic recovery performance, excellent thermal processing performance, and low cost. It is expected to be applied in fields such as high heat-resistant elastomers, recyclable thermoplastic elastic materials, films, foamed materials, automotive parts, and flexible products. This invention provides a new catalytic system and material design method for preparing high-performance polyolefin block elastomers from a single ethylene monomer.

[0033] Unless otherwise specified, the technical solutions described in this invention are all conventional solutions in the field, and the reagents or raw materials used are all purchased from commercial channels or are publicly available unless otherwise specified.

[0034] The α-diimine nickel catalyst used in this invention is prepared by condensation reaction of the ligand, and the obtained ligand is mixed with the metal source at a 1:1 ratio to obtain the corresponding catalyst.

[0035] The synthesis steps of the α-diimine nickel catalyst are as follows: (1) 20 mmol of 2,3-butanedione and the corresponding aniline were mixed at a molar ratio of 1:2 and added to a 250 mL round-bottom flask. 100 mL of toluene was added to dissolve the mixture, and 1 mL of formic acid was added as a catalyst. The mixture was purged with nitrogen for 5 min and refluxed at 120 °C for 48 h. The reaction was completed by TLC plate analysis. Heating was stopped when the substrate disappeared. Toluene was removed, and methanol was added for recrystallization to obtain the target product ligand.

[0036] (2) Under a nitrogen atmosphere, 2 mmol of ligand was added to a 100 mL Schlenk flask, dissolved in 20 mL of anhydrous dichloromethane, and 2 mmol of (DME)NiBr2 was added. The solution gradually turned dark red. After returning to room temperature, the reaction was carried out for 24 h. The solvent was concentrated, 20 mL of diethyl ether was added, and the mixture was vacuum filtered. The filter residue was washed with 20 mL of diethyl ether to obtain the target catalyst (i.e., α-diimine nickel catalyst).

[0037] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0038] In the following examples, the melting temperature of the polymer was determined using a TA Q2000 differential scanning calorimeter at a heating rate of 10 °C / min and a cooling rate of 10 °C / min, with a scanning range of -50 to 200 °C, using a two-stage heating curve. The tensile mechanical properties of the obtained polymer were tested using an Instron 3369 universal testing machine. The molecular weight and distribution of the polymer were determined using an Agilent PL-GPC220 high-temperature gel permeation chromatography system at a temperature of 150 °C. The mobile phase consisted of 1,2,4-trichlorobenzene with 0.05 wt% 2,6-di-tert-butyl-4-methylphenol added as an antioxidant. The flow rate was set to 1.0 mL / min, and PL EasiCal PS-1 was used as a standard.

[0039] Example 1 This embodiment describes a polymerization process at a polymerization temperature of 30°C, an ethylene pressure of 1 atm, a diethylzinc molar content 100 times that of the mixed catalyst, and a mixed catalyst consisting of a highly branched soft-segment α-diimide nickel catalyst (R1=Me, R2=Me, R3=H, X=Br) and a low-branched hard-segment α-diimide nickel catalyst (R1=Me, R2=...). t Chain shuttle polymerization was carried out with a molar ratio of Bu, R3=H, X=Br of 1:1 and a polymerization time of 30 min.

[0040] In this embodiment, the chain shuttle polymerization steps are as follows: (1) Weighing the chain shuttle catalyst: Weigh 5g of the highly branched soft segment α-diimine nickel catalyst in the glove box using an analytical balance. μ mol and low-branched hard segment α-diimine nickel catalyst 5 μ mol, with a molar ratio of 1:1, is fully dissolved in toluene and reserved for later use.

[0041] (2) Adjusting the polymerization temperature and pressure: Add toluene to the polymerization reactor, introduce ethylene, the ethylene pressure is 1 atm, and adjust the polymerization reactor temperature to 30 ℃.

[0042] (3) Addition of co-catalyst and chain shuttle: Methylaluminoxane dissolved in toluene is added to the polymerization reactor as a co-catalyst (the molar ratio of co-catalyst to mixed catalyst is 600:1); then diethylzinc dissolved in toluene is added to the polymerization reactor as a chain shuttle, and stirred for 5 min; the temperature of the polymerization reactor is kept at 30 ℃.

[0043] (4) Add catalyst for chain shuttle polymerization: Keep the temperature of the polymerization reactor at 30 °C, use a syringe to quantitatively extract the mixed catalyst prepared in step (1) and add it to the polymerization container. Rinse the remaining mixed catalyst at the feed port with toluene so that it all enters the polymerization reactor. The polymerization reaction time is 30 min.

[0044] (5) Termination of polymerization reaction: After the polymerization reaction reaches the polymerization time of 30 min, open the polymerization reactor and add a mixed solution of ethanol and hydrochloric acid. The volume fraction of hydrochloric acid in the mixed solution is 10%, which will quench the polymerization reaction.

[0045] (6) Polymer solution precipitation and drying: The polymer solution was poured into a mixed solution of ethanol and hydrochloric acid (the volume fraction of hydrochloric acid in the mixed solution was 10%), stirred to precipitate, filtered through a Buchner funnel, and dried in a vacuum drying oven at 60 °C for 8 hours to obtain 2.7 g of constant weight vinyl composite elastomer (NMR spectroscopy as shown in figure 1). Figure 9 (As shown).

[0046] High-temperature GPC analysis of the obtained polymer (vinyl composite elastomer) showed that, as Figure 1 As shown, the horizontal axis is log M w The molecular weight distribution exhibits a symmetrical unimodal distribution, and the molecular weight distribution varies within a relatively narrow range. M w = 185 kDa, M n =103 kDa Đ = 1.79). Figure 7 Studies of DSC and related physical properties show that chain shuttle polymerization can be achieved under these conditions to obtain a high-melting-point vinyl composite elastomer with a melting point of 129.4 °C.

[0047] Example 2 The only difference from Example 1 is that the molar content of diethylzinc is 200 times that of the mixed catalyst; the rest of the steps and parameters are the same as in Example 1, and 2.3 g of vinyl composite elastomer is obtained.

[0048] High-temperature GPC analysis of the obtained polymer showed that, Figure 2 As shown, the horizontal axis is log M w The molecular weight distribution exhibits a symmetrical unimodal distribution, and the molecular weight distribution varies within a relatively narrow range. M w = 82 kDa, M n = 33 kDa, Đ = 2.49). Figure 7Studies of DSC and related physical properties show that chain shuttle polymerization can be achieved under these conditions to obtain a vinyl composite elastomer with a melting point of 125.7 °C.

[0049] Example 3 The only difference from Example 1 is that the ethylene pressure is 5 atm; the rest of the steps and parameters are the same as in Example 1, and 6.2 g of constant weight vinyl composite elastomer is obtained.

[0050] High-temperature GPC analysis of the obtained polymer showed that, Figure 3 As shown, the horizontal axis is log M w The molecular weight distribution varies within a relatively narrow range. M w = 765 kDa, M n = 234 kDa, Đ = 3.26). Figure 7 Studies of DSC and related physical properties show that chain shuttle polymerization can be achieved under these conditions to obtain a high-melting-point vinyl composite elastomer with a melting point of 129.0 ℃. Figure 8 The figure shows the stress-strain curve. It can be seen from the figure that the elongation at break of the vinyl composite elastomer is 1079% and the breaking strength is 28 MPa.

[0051] Example 4 The only difference from Example 3 is that the molar content of diethylzinc is 500 times that of the mixed catalyst; the rest of the steps and parameters are the same as in Example 3, and 8.5 g of constant weight vinyl composite elastomer is obtained.

[0052] High-temperature GPC analysis of the obtained polymer showed that, Figure 4 As shown, the horizontal axis is log M w The molecular weight distribution is unimodal, and the molecular weight distribution varies within a relatively narrow range. M w = 127 kDa, M n = 40 kDa, Đ = 3.14). Figure 7 Studies of DSC and related physical properties show that chain shuttle polymerization can be achieved under these conditions to obtain a high-melting-point vinyl composite elastomer with a melting point of 129.4 °C. Figure 8 The figure shows the stress-strain curve. It can be seen from the figure that the elongation at break of the vinyl composite elastomer is 995% and the breaking strength is 9 MPa.

[0053] Example 5 The only difference from Example 3 is that the mixed catalyst consists of a highly branched soft-segment α-diimine nickel catalyst (R1=Me, R2=Me, R3=H, X=Br) and a low-branched hard-segment α-diimine nickel catalyst (R1=Me, R2=...). t The molar ratio of Bu, R3=H, X=Br was 4:1; the remaining steps and parameters were the same as in Example 3, and 6.1 g of constant weight vinyl composite elastomer was obtained.

[0054] High-temperature GPC analysis of the obtained polymer showed that, Figure 5 As shown, the horizontal axis is log M w The molecular weight distribution varies within a relatively narrow range. M w = 435 kDa, M n = 118 kDa, Đ = 3.68). Figure 7 Studies of DSC and related physical properties show that chain shuttle polymerization can be achieved under these conditions to obtain a high-melting-point vinyl composite elastomer with a melting point of 127.5 °C. Figure 8 The figure shows the stress-strain curve. It can be seen from the figure that the elongation at break of the vinyl composite elastomer is 1135% and the breaking strength is 11 MPa.

[0055] Example 6 The only difference from Example 5 is that the molar content of diethylzinc is 500 times that of the mixed catalyst; the rest of the steps and parameters are the same as in Example 5, and 11.5 g of constant weight vinyl composite elastomer is obtained.

[0056] High-temperature GPC analysis of the obtained polymer showed that, Figure 6 As shown, the horizontal axis is log M w The molecular weight distribution is unimodal, and the molecular weight distribution varies within a relatively narrow range. M w = 87 kDa, M n = 32 kDa, Đ = 2.70). Figure 7 Studies of DSC and related physical properties show that chain shuttle polymerization can be achieved under these conditions to obtain a high-melting-point vinyl composite elastomer with a melting point of 127.2 °C.

[0057] Comparative Example 1 The only difference from Example 3 is that the chain shuttle diethylzinc is not added; the other steps and parameters are the same as in Example 3, and 5.5 g of constant weight blend is obtained.

[0058] result: Figure 8 The stress-strain curves show that, compared to Example 3 with diethylzinc as the chain shuttle, the elongation at break of the blend in Comparative Example 1 without diethylzinc is only 513%. The overall mechanical properties of the vinyl composite elastomer are superior to those of the blend.

[0059] Comparative Example 2 The only difference from Example 5 is that the chain shuttle diethylzinc was not added; the other steps and parameters were the same as in Example 3, and 11.6 g of constant weight blend was obtained.

[0060] result: Figure 8 The stress-strain curves show that, compared to Example 5 with diethylzinc as the chain shuttle, the elongation at break of the blend in Comparative Example 2 without diethylzinc is only 510%. The overall mechanical properties of the vinyl composite elastomer are superior to those of the blend.

[0061] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing high-melting-point, high-toughness vinyl composite elastomers based on a bis-α-diimine nickel catalytic system, characterized in that, Includes the following steps: In the presence of a chain shuttle agent, ethylene is subjected to chain shuttle polymerization under the action of a mixed α-diimine nickel catalyst; The mixed α-diimine nickel catalyst comprises a highly branched soft-segment α-diimine nickel catalyst and a low-branched hard-segment α-diimine nickel catalyst; the molar ratio of the highly branched soft-segment α-diimine nickel catalyst to the low-branched hard-segment α-diimine nickel catalyst is 9:1 to 1:

9.

2. The method for preparing high-melting-point, high-toughness vinyl composite elastomers based on a dual α-diimine nickel catalytic system according to claim 1, characterized in that, The general structural formula of the highly branched soft-segment α-diimine nickel catalyst is shown in Formula (I); the general structural formula of the low-branched hard-segment α-diimine nickel catalyst is shown in Formula (II). Equation (I); Formula (II); In equation (Ⅰ), when R1 = Me, R2 = H, Me, Et or Ph, and R3 = H, Me, Et. i Pr、 t Bu or OMe; when R1 = Acenaphthyl, R2 = H, Me, Et or Ph, R3 = H, Me, Et, i Pr、 t Bu or OMe; when R1=H, R2=H, Me, Et or Ph, R3= H, Me, Et, i Pr、 t Bu or OMe; when R1 = Ph, R2 = H, Me, Et or Ph, R3 = H, Me, Et, i Pr、 t Bu or OMe; X is Me, Cl, or Br; In equation (II), when R1 = Me, R2 = H, Me, Et, t Bu, OMe, or Ph, R3 = H, Me, Et, i Pr、 t Bu or OMe; when R1=Acenaphthyl, R2=H, Me, Et, t Bu, OMe, or Ph, R3 = H, Me, Et, i Pr、 t Bu or OMe; when R1=H, R2=H, Me, Et, t Bu, OMe, or Ph, R3 = H, Me, Et, i Pr、 t Bu or OMe; when R1 = Ph, R2 = H, Me, Et, t Bu, OMe, or Ph, R3 = H, Me, Et, i Pr、 t Bu or OMe; X is Me, Cl or Br.

3. The method for preparing high-melting-point, high-toughness vinyl composite elastomers based on a dual α-diimine nickel catalytic system according to claim 1, characterized in that, The chain shuttle is diethylzinc; the amount of the chain shuttle added is 5 to 500 times the amount of the mixed α-diimine nickel catalyst.

4. The method for preparing high-melting-point, high-toughness vinyl composite elastomers based on a dual α-diimine nickel catalytic system according to claim 1, characterized in that, The chain shuttle polymerization reaction is carried out in an ethylene atmosphere, with an ethylene pressure of 1~10 atm, a polymerization temperature of 25~120 ℃, and a polymerization time of 1~60 min.

5. The method for preparing high-melting-point, high-toughness vinyl composite elastomers based on a dual α-diimine nickel catalytic system according to claim 1, characterized in that, A co-catalyst was also added to the reaction system.

6. The method for preparing high-melting-point, high-toughness vinyl composite elastomers based on a dual α-diimine nickel catalytic system according to claim 5, characterized in that, The co-catalyst is one or more of the following: methylaluminoxane, a mixture of triisobutylaluminum and tris(pentafluorophenyl)borane, a mixture of triisobutylaluminum and triphenylcarbazo(pentafluorophenyl)borate, and modified methylaluminoxane; the molar ratio of the co-catalyst to the mixed α-diimine nickel catalyst is 2000:1 to 100:

1.

7. The method for preparing high-melting-point, high-toughness vinyl composite elastomers based on a dual α-diimine nickel catalytic system according to claim 1, characterized in that, After the chain shuttle polymerization reaction is completed, the process also includes quenching, precipitation, and drying steps.

8. A vinyl composite elastomer prepared by the method for preparing high-melting-point, high-toughness vinyl composite elastomers based on a bis-α-diimine nickel catalytic system according to claims 1 to 7.

9. The application of the vinyl composite elastomer as described in claim 8 in the preparation of packaging, pipes, automobiles, electronic appliances, medical devices, films and foam materials.

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