A polyethylene-propylene-butene terpolymer and a method for producing the same

Abstract

The application discloses polyethylene-propylene-butylene ternary rubber and a preparation method thereof. Under the action of an initiator, a 1,2-structure regulator and a molecular mass distribution widening agent, an anionic polymerization reaction of butadiene / isoprene mixed monomers is carried out, then a branched chain extender is used to obtain wide-distribution high-vinyl polybutadiene-isoprene, then a selective hydrogenation is carried out through a titanium metallocene catalytic system, and thus the EPBR with wide molecular mass, suitable melt elasticity and stiffness and good processing performance is obtained. When the EPBR is mixed with carbon black, sulfur and other auxiliaries, excellent processing performance such as roll covering and calendering is exhibited. The compound rubber after mixing presents high tensile strength, low tensile deformation and good relaxation performance after vulcanization or micro-crosslinking, and the micro-crosslinked polymer main chain does not contain unsaturated double bonds, thus excellent anti-aging performance is exhibited, and rubber behavior is also exhibited.

Description

Technical Field

[0001] This invention relates to a ternary polyethylene-propylene-butene rubber (EPBR), particularly to a ternary rubber with a wide molecular weight distribution, high melt elasticity, and randomly distributed polyethylene-propylene-butene chains in the molecular chain, and also to its preparation method, belonging to the field of synthetic rubber technology. Background Technology

[0002] Existing ethylene propylene diene monomer (EPDM) rubbers include binary EPDM rubber, which is vulcanized with peroxides, and tertiary EPDM rubber, which contains 1.4–1.6% (mol) of unsaturation and can be vulcanized with ordinary sulfur. Both exhibit excellent ozone resistance, heat resistance, weather resistance, and aging resistance, and are widely used in automobiles and sealing components, waterproofing materials, wires and cables, heat-resistant hoses, and tapes. EPDM is also widely used due to its wide molecular weight distribution index (M). W / M n =2.0~2.5), its processing, calendering, and extrusion on an open mill are superior to ethylene-propylene-diene monomer (EPDM). EPDM is synthesized from ethylene, propylene, and a small amount of diene hydrocarbons using a vanadium-aluminum catalyst. Due to differences in monomer concentration and the concentration of monomers directly in contact with the active centers, as well as differences in the polymerization rates between monomers, the compositional distribution in the synthesized polymer molecules is uneven. For example, copolymers containing 73% or higher vinyl segments have higher elongation in vulcanizates, longer ethylene segment sequences, and worsened relaxation properties. Longer block ethylene segments are prone to crystallization, acting as junctions of lateral physical bonds. The presence of microcrystalline phases in the polymer, while increasing tensile strength, also increases tensile deformation—this is the duality of things. Currently, existing EPDM synthesis technologies struggle to form uniform alternating copolymers of ethylene, propylene, and a small amount of diene monomers, thus reducing the polymer's crystallinity tendency. In addition, commercially available EPDM has a Mooney viscosity of 18 to 90; the main chain is a saturated straight chain, and the iodine value of the side chain is 6 to 30 g / 100g, preferably 15 g / 100g.

[0003] It is not difficult to obtain a polymer with polyethylene-butene segments by partially hydrogenating a certain amount of 1,2-addition polybutadiene rubber. Currently, no such hydrides have been reported. Such derivative polymers are common lithium-based polymers and hydrogenated polystyrene-B-conjugated diene hydrides such as SEBS or SEPS. The iodine value of these polymers is 1 to 10 g / 100 g. Due to their narrow molecular weight distribution, they cannot be vulcanized with sulfur and exhibit the behavior of thermoplastic elastomers.

[0004] Existing nickel-based and rare-earth-catalyzed conjugated dienes are all high-cis rubbers, such as BR-9000, and rare-earth CB-24 and Nd-45, which are all high-cis 1,4-addition polybutadiene rubbers with a 1,4-addition unit content >95%. The polymerization solution contains catalyst residues, which can poison the active lithium-titanium oxide catalyst. Furthermore, after hydrogenation, the high-cis conjugated diene rubbers exhibit long polyvinyl groups in their molecular chains, and the hydrides crystallize, demonstrating high-modulus plastic behavior.

[0005] Chinese patent (CN1884328A) discloses a method for preparing branched high-vinyl polybutadiene rubber using molybdenum-based catalysis. This method employs Mo-based coordination catalytic polymerization to prepare structurally controllable branched high-vinyl polybutadiene rubber. The prepared polymer has suitable molecular weight and distribution, with a vinyl content exceeding 80%. The properties, length, distribution, and degree of branching of the branches are controllable and adjustable within a certain range, resulting in excellent processing and physical-mechanical properties. Chinese patent (CN105199028A) discloses a microstructure-adjustable high-vinyl polybutadiene rubber and its preparation method. This method uses an alkyl alcohol-substituted MOCl5 as the main catalyst and alkylaluminum as the co-catalyst. By adjusting the catalyst ratio and polymerization temperature, the polymerization behavior and product microstructure are controlled, resulting in a novel synthetic method for preparing polybutadiene with a vinyl content adjustable over a wide range of 60-90%. Meanwhile, a high-vinyl polybutadiene oil-extended rubber and its preparation method were disclosed in ("High-vinyl polybutadiene oil-extended rubber and its preparation method", Rubber Technology, April 2013), and a molecular design of star-shaped vinyl polybutadiene rubber was disclosed in ("Molecular design of star-shaped vinyl polybutadiene rubber", Proceedings of the 2004 International Rubber Conference (A)). The above technologies all belong to Ziegler-Natta improved coordination polymerization, and there is no report on the hydrogenation of their polymers.

[0006] For lithium-based polymers, US Patent (US4451576) describes anionic polymerization of BR with a vinyl content of 50-67% and a molecular weight distribution of 1.1-7.15. While the raw rubber exhibits excellent processing properties, it suffers from high molecular linearity, large cold flow, and low melt elasticity. Chinese Patent (CN102863576A) discloses a composite structure modifier suitable for preparing 3,4-isoprene rubber and its method for doing so. Specifically, it describes a composite structure modifier suitable for preparing 3,4-isoprene rubber and its method for doing so. At higher polymerization temperatures, it can efficiently adjust the 3,4-structure content of the polymer, resulting in a product with a 3,4-structure content exceeding 70%. When these polymers are used in automotive tire tread compounds, they impart good wet grip and low rolling resistance. Neither of these patents describes the hydrogenation of their polymers.

[0007] In summary, the preparation of EPDM and polystyrene-conjugated diene hydrides (SEBS or SEPS) are both mature technologies. Although high-vinyl polybutadiene rubber is also a hot topic, there are still no reports on its hydride preparation and behavior. Summary of the Invention

[0008] The existing coordination polymerization preparation of high vinyl polybutadiene rubber liquid has residual catalyst impurities that easily lead to hydrogenation poisoning when hydrogenated with titanium holocata catalysts. In addition, the existing synthesis of EPDM rubber is difficult to form uniform alternating chains of ethylene, propylene and a small amount of diene monomers, resulting in the presence of microcrystalline phases in the polymer molecular chain and high tensile deformation.

[0009] The primary objective of this invention is to provide a polyethylene-propylene-butene ternary rubber (EPBR) with a wide molecular weight distribution, high stiffness, high melt elasticity, and good processability. When mixed with additives such as carbon black and sulfur, it exhibits excellent processing properties such as roll wrapping and calendering. The compound rubber after mixing, after vulcanization or micro-crosslinking, exhibits high tensile strength, low tensile deformation, and good relaxation properties. Furthermore, the micro-crosslinked polymer backbone does not contain unsaturated double bonds, demonstrating excellent anti-aging properties and exhibiting the behavior of rubber.

[0010] The second objective of this invention is to provide a simple and low-cost method for preparing the EPBR. This method first synthesizes polybutadiene-isoprene rubber (BIR) with a vinyl content as high as 65-85% via anionic polymerization, and then selectively hydrogenates it to obtain polyethylene-propylene-butene ternary rubber (EPBR). In this method, butadiene and isoprene monomers can be completely converted, the polymerization reaction time is short, and various technical deficiencies and drawbacks existing in the preparation process of EPDM are avoided.

[0011] To achieve the above-mentioned technical objectives, this invention provides a method for preparing polyethylene-propylene-butene ternary rubber. The method involves continuously and uniformly adding an initiator and butadiene / isoprene mixed monomers to an anionic polymerization system containing a 1,2-structure modifier and a molecular weight distribution broadening agent to initiate and carry out a polymerization reaction. After the initiator and butadiene / isoprene mixed monomers are completely added, a branching agent is immediately added to continue the polymerization reaction. The resulting rubber solution is hydrogenated using a titanium holocatalyst system. The resulting rubber solution is then subjected to coagulation, dehydration, and drying sequentially to obtain the final product.

[0012] The synthesis of the polyethylene-propylene-butene ternary rubber of this invention is based on first synthesizing a broad-distribution, high-vinyl-content polybutadiene-isoprene rubber, and then selectively hydrogenating it. The broad-distribution, high-vinyl-content polybutadiene-isoprene rubber is achieved through anionic polymerization. During anionic polymerization, the molecular weight distribution of the polybutadiene rubber requires coordinated control of multiple operations: on the one hand, controlling the addition of the initiator and the butadiene / isoprene mixed monomers can, to a certain extent, control the molecular weight distribution of the polybutadiene-isoprene rubber. Utilizing the continuous and uniform addition of the initiator and polymerizing monomers ensures that new polymerization reactions are continuously initiated in the polymerization system, allowing the initiation and chain extension of the butadiene / isoprene mixed monomers to occur simultaneously, which is beneficial for broadening its polymer distribution. Firstly, the molecular weight distribution of the polymer was improved. Secondly, a molecular weight distribution broadening agent was introduced into the polymerization system to adjust the molecular weight and thus broaden the molecular weight distribution. Thirdly, a branching agent was introduced in the later stage of polymerization. By adding DVB monomer in one step, DVB generated random asymmetric branched chains, thereby improving the weight-average molecular weight and molecular weight distribution of the polymer. At the same time, a 1,2-structure regulator was introduced to adjust the high proportion of 1,2-structured butadiene units. Through the above optimizations, a number-average molecular weight of Mn = 100,000 to 150,000 and a molecular weight distribution index M were finally obtained. w / M n A polybutadiene-isoprene rubber with a viscosity of 2.0–2.5 and a high vinyl content is produced. Based on this, selective hydrogenation via a titanoceramic catalytic system allows for the selective hydrogenation of butadiene units, while isoprene retains most of its double bonds, which is beneficial for subsequent vulcanization and crosslinking.

[0013] This invention employs anionic polymerization to synthesize polybutadiene-isoprene rubber. Anionic polymerization is a common method in the prior art, using solvents such as n-hexane and / or cyclohexane, and in an anhydrous environment. The initiator used in the polymerization is generally alkyl lithium, specifically n-butyllithium (NBL), which is well-known in the industry.

[0014] As a preferred embodiment, the 1,2-structure modifier is at least one of tetrahydrofurfuryl ethyl ether, bis(tetrahydrofurfuryl propane), and tetrahydrofurfuryl hexyl ether. As a more preferred embodiment, the amount of the 1,2-structure modifier relative to the butadiene monomer is 0.5–1.0 g / 100 g. To ensure a sufficient number of 1,2-structure butadiene units in the BIR molecule, this invention necessitates the addition of a highly polar 1,2-structure modifier during butadiene polymerization. Preferably, it is a Lewis base with a high boiling point and high polarity. Lewis bases with high boiling points and high polarity are relatively stable at high temperatures, and the increased polarity enhances the modulating function. These can be Lewis base compounds such as tetrahydrofurfuryl ethyl ether, bis(tetrahydrofurfuryl propane), and tetrahydrofurfuryl hexyl ether, which do not contain active hydrogen but have polyether groups. The polybutadiene-isoprene rubber obtained by using a 1,2-structure modifier has a higher number of vinyl units, which can prevent the formation of long polyethylene chains in the hydrogenated polymer, thus avoiding physical nodes or crystalline phases in the polymer.

[0015] As a preferred embodiment, the molecular weight distribution broadening agent is a hindered amine diazo compound. As a more preferred embodiment, the hindered amine diazo compound is DBN (1,5-diazobicyclo[4,3,0]non-5-ene) and / or DBU (1,5-diazobicyclo[5,4,0]non-5-ene). As a more preferred embodiment, the amount of the molecular weight distribution broadening agent relative to the butadiene monomer is 0.1–0.2 g / 100 g. Typically, a molecular weight distribution (Mg) broadening agent is obtained through anionic polymerization. w / M n Achieving a molecular weight distribution (M) greater than 1.8 is quite difficult, as seen in existing lithium-based SBS, SEBS, SIS, and other polymer elastomers. w / M n <1.05. For vulcanized rubber, a wide molecular weight distribution is essential for subsequent processing such as mixing, extrusion, calendering, and sheeting of raw rubber with fillers and minor components. This invention effectively adjusts the molecular weight distribution during BIR synthesis by adding appropriate proportions and types of molecular weight broadening agents.

[0016] As a preferred embodiment, the initiator and butadiene / isoprene mixed monomer are added at a time of not less than 40 minutes. Alternatively, the initiator and butadiene / isoprene mixed monomer are added separately and simultaneously. The most preferred feeding method for NBL and butadiene / isoprene mixed monomer in this invention is as follows: butadiene and NBL are added simultaneously and uniformly to the polymerization environment via two separate pathways, with each feeding time not less than 40 minutes. Because anionic polymerization is characterized by rapid initiation, rapid propagation, and rapid termination, this invention, by controlling the addition method of the initiator and butadiene / isoprene mixed monomer, enables monomer initiation and chain extension to occur simultaneously and continuously, which is beneficial for broadening the molecular weight of the polymer.

[0017] As a preferred embodiment, the isoprene monomer has a mass of 2.5–5.0% of the butadiene monomer mass. The introduction of a small amount of isoprene units not only generates some propenyl and / or isopropenyl units, but also retains some alkenyl groups during selective hydrogenation, which is beneficial for subsequent sulfurization crosslinking.

[0018] As a preferred embodiment, the branching agent is DVB. As a preferred embodiment, the amount of the branching agent relative to the butadiene monomer is 0.08–0.20 g / 100 g. The branching agent of this invention is preferably divinylbenzene (DVB), and its preferred addition method is to add DVB immediately after the butadiene / isoprene mixed monomer and NBL are continuously added to the polymerization system. In the polymerization environment, DVB undergoes random asymmetric branching as the polymer chain grows, which can improve the polymer's weight-average molecular weight and molecular weight distribution, and also improve the melt elasticity of the polymer raw rubber. These are all beneficial to improving the processing performance of the raw rubber. At the same time, the amount of branching agent needs to be strictly controlled. If the proportion of branching agent is too low, the branching effect will not be achieved; if the proportion of branching agent is too high, cyclic or gel macromolecules are easily formed, which are both unfavorable.

[0019] As a preferred embodiment, the polymerization process is as follows: the initiator and butadiene / isoprene mixed monomers are continuously and uniformly added to an anionic polymerization system containing a 1,2-structure modifier and a molecular weight distribution broadening agent within 40-50 min to initiate polymerization, and the polymerization reaction is carried out under the conditions of a pressure of 3.0-3.5 bar and a temperature of 50-65°C. After the initiator and butadiene / isoprene mixed monomers are completely added, the branching agent is immediately and rapidly added within 1 min, and the polymerization reaction is continued for 20-40 min at a temperature not exceeding 65°C.

[0020] As a preferred embodiment, the titanium-ceramic catalytic system comprises a dicyclopentadiene titanium dichloride main catalyst and a co-catalyst composed of methyl phthalate and / or dimethyl phthalate, wherein the molar ratio of the co-catalyst to the main catalyst is 0.3–0.5:1. The titanium-ceramic catalytic system employed in this invention exhibits good selectivity, capable of hydrogenating all polybutadiene polymerization units while exhibiting partial selective hydrogenation of polyisoprene units. The degree of hydrogenation is not high, which explains why existing polystyrene-isoprene polymers such as SIS cannot be synthesized into SEPS through the catalytic hydrogenation of dicyclopentadiene titanium dichloride.

[0021] As a preferred embodiment, the hydrogenation reaction conditions are: pressure 13–18 bar, temperature 70–95 °C, time 120–150 min, and the amount of catalyst system added relative to the adhesive solution is 0.035–0.040 g / 100 g, where the catalyst system is measured by the mass of the main catalyst and the adhesive solution is measured by dry basis mass. Under the preferred hydrogenation reaction conditions, the polybutadiene units in the BIR molecule can be completely hydrogenated or have a residual iodine value of 1.5–3.0 g / 100 g, and the isoprene polymerization units can be partially hydrogenated or not hydrogenated. The most preferred BIR hydrogenated polymer EPBR molecule has a residual iodine value of 3–6 g / 100 g. Retaining a small number of unsaturated double bonds is beneficial for the cross-linking of the polymer with sulfur, while the micro-crosslinked network molecular chain after molding does not contain unsaturated double bonds, maximizing the ozone resistance, heat resistance, weather resistance, and aging resistance of the network product.

[0022] The total conversion rate of butadiene / isoprene monomers in the BIR synthesis process of this invention is 99-100%.

[0023] The present invention also provides a polyethylene-propylene-butene ternary rubber, which is obtained by the preparation method described above.

[0024] As a preferred embodiment, the number-average molecular weight Mn of the polyethylene-propylene-butene ternary rubber is 100,000 to 150,000, and the molecular weight distribution index M0 is [missing information]. w / M n =2.0~2.5 Mooney viscosity ML ( 1+4 =18~80.

[0025] The preferred preparation method of the EPBR raw rubber BIR of the present invention is as follows: A quantitative amount of hexane or cyclohexane solution is added to a clean steel polymerization reactor, along with quantitative amounts of 1,2-structure modifier and molecular weight distribution broadener. The reactor solution is then heated to 50-55°C. Within 40-50 minutes, butadiene / isoprene mixed monomers and NBL are continuously and uniformly added to the polymerization reactor. After the monomers are added, DVB cyclohexane solution is rapidly added within 1 minute, and the reaction continues for another 30 minutes to obtain BIR rubber solution. During this period, if necessary, cooling water is introduced to remove the heat of reaction and maintain the polymerization temperature not higher than 65°C. Finally, the rubber solution is pressurized with nitrogen into a hydrogenation reactor for hydrogenation unit for later use.

[0026] The preferred preparation method of the EPBR raw rubber BIR hydrogenation of the present invention is as follows:

[0027] Add n-butyllithium to the BIR colloid solution in the hydrogenation reactor, then activate by stirring for 20 min at 40–80 °C and 10–13 bar hydrogen pressure. Next, add half of the total co-catalyst and activate for another 15 min. Then add the main catalyst and hydrogenate at 13–18 bar and 70–95 °C for 60 min. Add the remaining co-catalyst and hydrogenate for another 60–90 min. Stop hydrogenation when the iodine value of the polymer reaches 3–6 g / 100 g. Finally, after terminating the hydrogenation process, add a small amount of antioxidant, then coagulate, dehydrate, and dry to obtain block EPBR raw rubber.

[0028] The EPBR raw rubber of the present invention is processed and vulcanized in the same way as existing general-purpose EPDM and conjugated diene rubbers.

[0029] Compared with existing technologies, the beneficial effects of the technical solution of this invention are as follows:

[0030] Existing EPDM rubber has drawbacks such as long polymerization reaction time, incomplete conversion of monomers requiring degassing, distillation drying, and recycling from the rubber solution, and a long preparation process.

[0031] The EPDM raw rubber BIR of this invention has a short polymerization time and controllable molecular weight distribution during preparation, and can be prepared using existing anionic polymerization technology. The synthesized raw rubber BIR can be hydrogenated using existing titanium holocata catalysts. The hydrogenated polymer EPBR has a relatively low iodine value. After sulfur vulcanization (or micro-crosslinking), the main chain does not contain double bonds, giving the vulcanized rubber excellent anti-aging and UV resistance properties. The raw rubber can be subsequently mixed, processed, and vulcanized using existing general-purpose EPDM and conjugated diene rubbers.

[0032] The EPBR prepared by this invention retains the advantages of the original BIR rubber, with a wide molecular weight range, suitable melt elasticity and stiffness, and good processing performance. The vulcanized rubber not only has excellent physical properties, but also can be compared with the existing EPDM in terms of heat resistance and anti-aging properties.

[0033] The EPBR preparation process of this invention is a homogeneous reaction, simple to prepare, and can be synthesized using existing mature processes, making it easy to control and industrialize. Attached Figure Description

[0034] Figure 1 GPC chromatogram of molecular weight and distribution of EPDM 4045M.

[0035] Figure 2 H for EPDM 4045M 1 -NMR spectrum.

[0036] Figure 3 The GPC spectrum of the hydrogenated polymer EPBR-1# raw rubber BIR is shown.

[0037] Figure 4 H is the hydrogenated polymer EPBR-1# raw rubber BIR. 1 -NMR.

[0038] Figure 5 H for hydrogenated polymer EPBR-1# 1 -NMR.

[0039] Note: H 1 The protons with chemical shifts of 5.573–5.373 in the NMR spectrum are protons on -CH=CH-, and the protons with chemical shifts of 4.995–4.956 are protons on -CH=CH2, i.e., H in the polymer or hydride. 1 Chemical shifts of 5.5–4.3 in NMR spectra can be considered as protons on unsaturated carbon-carbon double bonds. Detailed Implementation

[0040] The following examples are intended to further illustrate and describe the content of the present invention, and do not constitute a limitation on the scope of protection of the claims of the present invention.

[0041] In the following examples, the number-average molecular weight and molecular weight distribution index of the polymers were determined using gel permeation chromatography (GPC); H2 was used. 1 - The microstructure of the polymer was quantitatively determined by NMR spectroscopy; the mechanical properties of the vulcanized rubber were tested according to GB / T36089-2018.

[0042] Example 1 (Control Experiment)

[0043] Commercially available EPDM 4045M ethylene propylene diene monomer (EPDM) rubber was subjected to gel permeation chromatography (GPC) and H2O chromatography. 1 -NMR spectroscopy analysis. Results: Molecular mass and distribution are shown in the GPC chromatogram. Figure 1 H 1 - See NMR spectrum Figure 2 .

[0044] Example 2

[0045] Under nitrogen protection, 3000 mL of cyclohexane, 2.2 mL of ETE, and 0.4 mL of DBN were added to a 5L polymerization reactor. Stirring was started and the material temperature was raised to 52°C. At this time, 8.0 mL of 0.6 mol / L NBL and a mixed monomer consisting of 550 mL of butadiene and 25 mL of isoprene were continuously added to the polymerization reactor. The continuous addition time for both was 40 min. Immediately after the monomers were added, 4.0 mL of cyclohexane solution with a mass fraction of 10% DVB was added to the polymerization reactor and polymerization was continued for 30 min. During this period, the polymerization temperature was maintained not higher than 65°C, and the molecular weight (BIR, calibrated as BIR-1#) and Mooney viscosity of the polymer were continuously analyzed until the set requirements were met.

[0046] The gel solution was pressurized into a hydrogenation reactor under nitrogen pressure, and 15 mL of 0.6 mol / L NBL was added. The temperature was raised to 75°C, and the mixture was stirred and activated at 13 bar hydrogen pressure for 20 min to convert butyllithium to lithium hydride. Then, 4 mL of a cyclohexane solution of 0.02 mol / L dimethyl phthalate and methyl o-methyl benzoate (co-catalyst) was added, and the mixture was activated for another 15 min. At this point, 0.15 g of dicyclopentadiene was added, and the mixture was stirred at 15 bar hydrogen pressure for 60 min, controlling the maximum temperature not to exceed 105°C. After the hydrogenation temperature dropped to 85°C, another 4 mL of co-catalyst was added. The hydrogenation temperature then showed a slight upward trend again. Stirring continued for 70 min until the iodine value of the hydrogenated product was 5 g / 100 g, at which point hydrogenation was stopped. After the hydrogenation gel solution was terminated with water, a small amount of antioxidant was added. After coagulation, dehydration, and drying, 360 g of block EPBR raw rubber was obtained, labeled as EPBR-1#. The GPC of the polymer raw rubber BIR is attached. Figure 3 BIR raw rubber and EPBR-1#H 1 -NMR spectra are attached. Figure 4 and Figure 5 GPC, microstructure, and Mooney viscosity (ML) of the polymer. 1+4 See Table 1.

[0047] Example 3

[0048] The process conditions of Example 2 were kept unchanged, except that 2.4 mL of ETE, 8.5 mL of NBL, 0.45 mL of DBN, and 5.0 mL of cyclohexane solution of DVB were added. The hydrogenation unit used 0.14 g of dicyclopentadiene as the main catalyst and 7 mL of co-catalyst, with a total hydrogenation reaction time of 150 min. As a result, 358 g of raw rubber (labeled as EPBR-2#) was obtained. The GPC, microstructure, and Mooney viscosity (ML) of the polymer were also analyzed. 1+4 See Table 1.

[0049] Example 4

[0050] The relevant process conditions in Implementation 1 were kept unchanged, except that 1.9 mL of tetrahydrofurfuryl ether, 0.41 mL of DBU, 9.0 mL of NBL, and 4.5 mL of cyclohexane solution of DVB were added. The hydrogenation unit was operated at a hydrogenation pressure of 14 bar and a hydrogenation time of 130 min. As a result, 359 g of raw rubber (labeled as EPBR-3#) was obtained. The GPC, microstructure, and Mooney viscosity (ML) of the polymer were analyzed. 1+4 See Table 1.

[0051] Example 5

[0052] The relevant process conditions in Implementation 1 were kept unchanged, except that the following additions were made: 20 mL of isoprene, 2.2 mL of tetrahydrofurfuryl ether, 0.40 mL of DBU, 6.0 mL of NBL, 4.0 mL of cyclohexane solution of DVB, and the addition time of NBL and monomers was 45 min. The hydrogenation unit had a hydrogenation pressure of 14 bar and a hydrogenation time of 140 min. The result was 353 g of raw rubber (labeled as EPBR-4#). The GPC, microstructure, and Mooney viscosity (ML) of the polymer were analyzed. 1+4 See Table 1.

[0053] Example 6

[0054] The relevant process conditions in Implementation 5 were kept unchanged, except that 15 mL of isoprene was added. The hydrogenation time in the hydrogenation unit was 120 min. As a result, 351 g of raw rubber (labeled EPBR-5#) was obtained. The GPC, microstructure, and Mooney viscosity (ML) of the polymer were analyzed. 1+4 See Table 1.

[0055] Comparative Example-1#

[0056] The relevant process conditions in Implementation 1 were kept unchanged, except that 35 mL of isoprene was added and the hydrogenation time in the hydrogenation unit was 110 min. As a result, 362 g of raw rubber was obtained (calibrated to ratio-1#). The GPC, microstructure, and Mooney viscosity (ML) of the polymer were analyzed. 1+4 See Table 1.

[0057] Comparative Example-2#

[0058] The relevant process conditions in Implementation 1 were kept unchanged, except that the hydrogenation time in the hydrogenation unit was 100 min. As a result, 360 g of raw rubber was obtained (calibrated as ratio-2#). The GPC, microstructure, and Mooney viscosity (ML) of the polymer were analyzed. 1+4 See Table 1.

[0059] Comparative Example-3#

[0060] The relevant process conditions in Implementation 1 were kept unchanged, except that 10 mL of isoprene was added and the hydrogenation time in the hydrogenation unit was 150 min. As a result, 347 g of raw rubber was obtained (standardized to ratio -3#). The GPC, microstructure, and Mooney viscosity (ML) of the polymer were analyzed. 1+4 See Table 1.

[0061] Comparative Example-4#

[0062] The relevant process conditions in Implementation 1 were kept unchanged, except that the continuous feeding time for the mixed monomers and NBL was 20 min, and the reaction polymerization time after the addition of DVB was 25 min. As a result, 359 g of hydrogenated raw rubber (labeled as Comparison-4#) was obtained. The GPC, microstructure, and Mooney viscosity (ML) of the polymer were also analyzed. 1+4 See Table 1.

[0063] Comparative Example-5#

[0064] The process conditions of Example 1 were kept unchanged, except that 1.5 mL of ETE was added. As a result, 359 g of hydrogenated raw rubber (standardized to ratio -5#) was obtained. The GPC, microstructure, and Mooney viscosity (ML) of the raw rubber were also determined. 1+4 See Table 1.

[0065] Table 1 Polymer Characterization in the Examples

[0066]

[0067] As shown in Table 1, the shorter feeding time of monomers and NBL results in a smaller molecular weight distribution index of the polymer; the lower amount of isoprene and the longer hydrogenation time result in a lower iodine value of the hydrogenated rubber; the lower amount of regulator results in a lower content of vinyl units in the polymer; and the shorter hydrogenation time results in a higher iodine value of the hydride.

[0068] Example 6

[0069] The trial samples in Table 1, such as EPBR-1#, EPBR-2#, EPBR-3#, EPBR-4#, EPBR-5#, and the comparative samples, commercially available EPDM and comparative samples-1#,-3#, and-5#, were mixed, vulcanized, and tested with carbon black, sulfur, accelerators, and other minor ingredients according to national standards. Their physical properties are shown in Table 2.

[0070] Table 2 Physical properties of vulcanizates

[0071]

[0072] Note: 1) Formula (parts by weight): raw rubber, 100 parts; stearic acid, 1.0 part; zinc oxide, 3 parts; rubber oil 4010, 10 parts; antioxidant RD, 1.0 part; accelerator TBBS, 2 parts; accelerator TMTD, 1.0 part; N330, 50 parts; sulfur, variable (of which: EPDM dosage is 3.0; other samples and control samples dosage is 4.5).

[0073] 2) Vulcanization conditions: 160℃ × 30min

[0074] As shown in Table 2, when the iodine value of hydrogenated rubber is too low, the crosslinking density of the vulcanized rubber is low and the physical properties are poor; when the vinyl unit content of hydrogenated rubber is low, the deformation of the hydrogenated rubber is high; when the iodine value of hydrogenated rubber is too high, the anti-aging properties of the vulcanized rubber are poor.

Claims

1. A method for preparing a polyethylene-propylene-butene ternary rubber, characterized in that: The initiator and butadiene / isoprene mixed monomers were continuously and uniformly added to an anionic polymerization system containing a 1,2-structure modifier and a molecular weight distribution broadening agent to initiate and carry out the polymerization reaction. After the initiator and butadiene / isoprene mixed monomers were completely added, a branching agent was immediately added to continue the polymerization reaction. The resulting polymer solution was hydrogenated using a titanium holometre catalytic system. The resulting polymer solution was then subjected to coagulation, dehydration and drying in sequence to obtain the final product. The amount of the 1,2-structure modifier relative to the butadiene monomer is 0.5~1.0 g / 100 g; The amount of the molecular weight distribution broadening agent relative to the butadiene monomer is 0.1~0.2g / 100g; The molecular weight distribution broadening agent is a hindered amine diazo compound; The initiator and butadiene / isoprene mixed monomer are added at a time of not less than 40 minutes; The initiator and butadiene / isoprene mixed monomer are added separately and simultaneously. The mass of the isoprene monomer is 2.5-5.0% of the mass of the butadiene monomer; The hydrogenation reaction takes 120-150 minutes.

2. The method for preparing a polyethylene-propylene-butene ternary rubber according to claim 1, characterized in that: The 1,2-structure modifier is at least one of tetrahydrofurfuryl ethyl ether, bis(tetrahydrofurfuryl propane) and tetrahydrofurfuryl hexyl ether.

3. The method for preparing a polyethylene-propylene-butene ternary rubber according to claim 1, characterized in that: The hindered amine diazo compound is DBN and / or DBU.

4. The method for preparing a polyethylene-propylene-butene ternary rubber according to claim 1, characterized in that: The branching agent is DVB.

5. A method for preparing a polyethylene-propylene-butene ternary rubber according to claim 1 or 4, characterized in that: The amount of the branching agent relative to the butadiene / isoprene mixed monomer is 0.08~0.20g / 100g.

6. A method for preparing a polyethylene-propylene-butene ternary rubber according to claim 1, 2, 3 or 4, characterized in that: The polymerization process is as follows: the initiator and butadiene / isoprene mixed monomers are continuously and uniformly added to an anionic polymerization system containing 1,2-structure regulator and molecular weight distribution broadener within 40-50 min to initiate polymerization. The polymerization reaction is carried out under the conditions of pressure 3.0-3.5 bar and temperature 50-65℃. After the initiator and butadiene / isoprene mixed monomers are added, the branching agent is immediately and rapidly added within 1 min, and the polymerization reaction is continued for 20-40 min at a temperature not higher than 65℃.

7. The method for preparing a polyethylene-propylene-butene ternary rubber according to claim 1, characterized in that: The titanium catalytic system comprises a dicyclopentadiene titanium dichloride main catalyst and a co-catalyst composed of methyl o-methylbenzoate and / or dimethyl phthalate, wherein the molar ratio of the co-catalyst to the main catalyst is 0.3~0.5:

1.

8. A method for preparing a polyethylene-propylene-butene ternary rubber according to claim 1 or 7, characterized in that: The conditions for the hydrogenation reaction are: pressure of 13~18 bar, temperature of 70~95℃, and the amount of the titanium catalytic system added relative to the adhesive solution is 0.035~0.040 g / 100 g, wherein the catalytic system is measured by the mass of the main catalyst and the adhesive solution is measured by the dry basis mass.

9. A polyethylene-propylene-butene ternary rubber, characterized in that: It is obtained by the preparation method described in any one of claims 1 to 8.

10. A polyethylene-propylene-butene ternary rubber according to claim 9, characterized in that: Number-mean molecular weight Mn = 100,000~150,000, molecular weight distribution index M w / M n =2.0~2.5 Mooney viscosity (ML) （1+4） =18~80.

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