A polyethylene-propylene-butene rubber, its preparation method and use in TPV sealants

Abstract

This invention discloses a polyethylene-propylene-butene rubber, its preparation method, and its application in TPV sealing materials, belonging to the field of polymer materials technology. The polyethylene-propylene-butene rubber has the following structural expression: R1 and R2 are independently selected from hydrogen or C1-C3 alkyl groups; R3 and R4 are independently selected from hydrogen, C1-C3 alkyl groups, or vinyl groups; Ar is phenyl or a substituted phenyl group; x, n, y, m, and z are all greater than or equal to 0, and the sum of x, n, y, and m is greater than 0, (x+y+z) / (m+n) = 17-38. This polyethylene-propylene-butene ternary rubber is blended and vulcanized with fillers such as PP to prepare PP / EPBR-TPV granules, which are used as sealing strips. These granules have advantages such as high strength, good elasticity, low deformation, easy injection molding, a bright and full surface, and heat resistance and aging resistance.

Description

Technical Field

[0001] This invention relates to a polyethylene-propylene-butene rubber (EPBR), as well as its preparation method and its application in TPV sealing materials, belonging to the field of novel rubber material technology. Background Technology

[0002] Traditional sealing strip materials typically include soft polyvinyl chloride (PVC), natural rubber, styrene-butadiene rubber, or diene rubber. However, soft PVC sealing strips have large compression deformation, while diene rubber used as sealing strips has many defects such as being difficult to process and having poor aging resistance.

[0003] Currently, automotive sealing strips are the largest category of rubber-using accessories in automobiles besides tires. They are mainly used in areas with gaps, such as doors, windows, and hoods, serving functions such as sealing, shock absorption, sound insulation, and decoration. They prevent external wind, sand, rain, and dust from entering the vehicle, thereby improving the lifespan of automotive components and passenger comfort. Although they account for a small percentage of the total cost of a vehicle, they play a crucial role in its quality. In the last century, the main materials for domestically produced automotive sealing strips were soft PVC, CR, and NR. With the rapid development of the automotive industry, the appearance quality and internal performance of soft PVC, CR, and NR sealing strips, especially their weather resistance and service life, can no longer meet the needs of passenger cars and other high-end vehicles. Therefore, both domestically and internationally, the production and application of EPDM automotive sealing strips have been gradually promoted. With the continuous updating and development of EPDM, novel EPDM possesses both excellent physical properties and processability, while also allowing for controllable branching of long molecular chains. With the rapid development of the automotive industry, domestic rubber sealing strip manufacturers have achieved rapid growth. The vast majority of automotive sealing strip materials use ethylene propylene diene monomer (EPDM). Due to the low content of unsaturated double bonds in the EPDM molecular chain, it exhibits excellent weather resistance, heat resistance, UV resistance, good processability, and low compression set, making it the preferred material for sealing strip production. EPDM is now used in all automotive rubber components. In the development of EPDM, developing materials with excellent physical and mechanical properties, good processability, good vulcanization performance, and the ability to increase extrusion speed to boost output and production capacity is a crucial objective.

[0004] Dynamically vulcanized thermoplastic elastomers are a materials science and technology term introduced in 2011. This involves melt-blending raw rubber with non-vulcanizable thermoplastic polymers such as PP, PVC, and PA resins in a high-temperature, high-shear blending device. Simultaneously, under the action of a crosslinking agent, the rubber phase is vulcanized, resulting in vulcanized rubber particles with a size of approximately micrometers, uniformly dispersed in the resin. This structure is highly stable and does not undergo changes in physical properties during processing. Examples include EPDM / PP, NBR / HPVC, and ACM / PA. This is the opposite of traditional rubber vulcanization, which typically uses a flat vulcanizing machine. The prepared raw rubber is fixed in the cavity of a rubber mold, heated to a certain temperature, and then the vulcanization reaction begins; this can also be described as a form of "static vulcanization." Currently, dynamically vulcanized EPDM / PP thermoplastic elastomer (EPDM / PP-TPV) remains a novel material for automotive sealing strips. EPDM / PP-TPV is gradually replacing thermosetting, non-recyclable EPDM. It possesses both the excellent physical and mechanical properties of elastomers and the excellent processing characteristics of plastics, making it easy to mold and recycle, thus saving resources and being environmentally friendly. Research on EPDM / PP blending began in the 1960s, initially using simple blending methods. In 1973, Fischer employed partial vulcanization. In the early 1980s, R. Patel et al., building on previous work, adopted dynamically vulcanized EPDM / PP-TPV. The first two processes suffer from drawbacks such as uneven mixing and instability. Fully dynamic vulcanization involves adding a crosslinking agent during compounding to crosslink the rubber components and simultaneously micro-disperse the rubber particles. Domestic research focuses on the theoretical study of using dynamic full vulcanization technology to produce TPV with different hardness grades, while foreign countries have shifted from theoretical research to application development, and are more inclined to develop TPV with lower hardness grades, new manufacturing processes, processing methods and expanded applications. For example, Chinese patent CN104592652A discloses a method for preparing automotive rubber sealing strips. The method involves mixing 80-100 parts of EPDM, 0.4-0.8 parts of accelerator, 1.3-1.5 parts of antioxidant, 60-80 parts of carbon black, and 13-17 parts of softening oil in a mixer at 100-110℃ for 5-8 minutes. Then, 4-8 parts of dicumyl peroxide (DCP) and 2-4 parts of TAIC are added, and the mixture is mixed for another 4-5 minutes. After cooling, the mixture is vulcanized in a salt bath vulcanizing bed at 230-250℃ for 1.5-2 minutes. The vulcanized rubber compound is then granulated and dried. Finally, the granules are extruded using an extruder. The resulting granules possess thermoplastic vulcanizate properties. Vulcanizate (TPV) exhibits characteristic behavior and belongs to dynamic vulcanization technology. Compared with traditional sulfur microwave vulcanization molding technology, it has the advantages of safe processing, convenience, and high preparation efficiency.

[0005] Existing EPDM boasts the highest filling capacity among all synthetic rubbers, along with excellent weather resistance and heat resistance. However, the raw rubber contains residual vanadium catalyst, which is difficult to remove, leading to defects such as catalytic aging in the finished product during use. Furthermore, EPDM suffers from low production efficiency during synthesis, with monomer conversion rates, particularly propylene, below 48%, and ethylene not being fully converted in a single step. The need for monomer recycling and refining results in a long process flow and high production costs. Meanwhile, the technology of using polyethylene-propylene-butene rubber (EPBR), which exhibits low unsaturation, good aging resistance, easy processing and molding, high filling capacity, and low cost, to produce TPV as a rubber sealing strip material has not yet been reported. Summary of the Invention

[0006] The existing EPDM technology contains residual vanadium catalyst, which has the function of catalytic aging in the product. In addition, the synthesis and preparation of EPDM requires monomer recycling and purification, which is a long process and has high preparation cost. Furthermore, the TPV prepared by combining EPDM with polypropylene (PP) has defects such as large compression deformation and small defects on the surface of the product, which are not bright.

[0007] The first objective of this invention is to provide a polyethylene-propylene-butene rubber (EPBR) with an alkyl chain as its main chain, which has good compatibility with PP and does not cause phase separation. At the same time, both the main chain and side chains of EPBR contain double bonds, which can form a network of macromolecules through vulcanization. Under strong mixing, fine elastic rubber particles are formed and dispersed in polypropylene (melt), dispersing PP into a continuous phase. The cross-linked network of EPBR forms a 3-5 micrometer dispersed phase, and the softening oil is locked to form a soft elastic rubber phase. That is, the continuous phase of PP and the oil-filled cross-linked network of EPBR form an "island" structure, which produces a stable physical junction (or physical cross-linking point). Furthermore, EPBR has a suitable and uniformly distributed side alkyl content, which reduces its crystallization and deformation and increases its elasticity. When prepared into TPV, it can achieve good comprehensive physical properties and processing performance.

[0008] The second objective of this invention is to provide a method for preparing polyethylene-propylene-butene rubber that is simple, low-cost, can be produced using existing mature processes, and is easy to control and industrialize.

[0009] The third objective of this invention is to provide an application of polyethylene-propylene-butene rubber in TPV sealing materials. PP / EPBR-TPV granules are prepared by blending and vulcanizing polyethylene-propylene-butene ternary rubber with fillers such as PP and used as sealing strips. This process offers advantages such as high strength, good elasticity, low deformation, easy injection molding, a glossy and full surface, and heat and aging resistance. It avoids the shortcomings and defects of existing PP / EPDM-TPV sealing strips, as well as the defects of existing SEBS / PP alloys, such as sticky surface after oil filling, poor heat resistance, large deformation, and easy breakage due to phase separation.

[0010] To achieve the above-mentioned technical objectives, the present invention provides a polyethylene-propylene-butene rubber having the following structural expression:

[0011]

[0012] in,

[0013] R1 and R2 are independently selected from hydrogen or C1-C3 alkyl groups;

[0014] R3 and R4 are independently selected from hydrogen, C1-C3 alkyl groups or vinyl groups;

[0015] Ar is a phenyl or substituted phenyl;

[0016] x, n, y, m, and z are the degree of aggregation. x, n, y, m, and z are all greater than or equal to 0, and the sum of x, n, y, and m is greater than 0. (x+y+z) / (m+n) = 17~38.

[0017] The polyethylene-propylene-butene rubber has an unsaturation degree of 2.5-5.5% by iodine value method and a side alkyl chain mass ratio of 28-60%.

[0018] The polyethylene-propylene-butene rubber (EPBR) of this invention has a polyethylene main chain containing only a small amount of vinylidene, which has a structure similar to that of the PP main chain. The two have good compatibility and do not produce phase separation. At the same time, both the EPBR main chain and side chains contain a small number of double bonds, which can form a network of macromolecules through vulcanization. Under strong mixing, fine elastic rubber particles are formed and dispersed in polypropylene (melt), dispersing PP into a continuous phase. The cross-linked network of EPBR forms a 3-5 micrometer dispersed phase, and the softening oil is locked to form a soft elastic rubber phase. That is, the continuous phase of PP and the oil-filled cross-linked network of EPBR form an "island" structure, which produces a stable physical junction (or physical cross-linking point).

[0019] The EPBR of the present invention has a suitable and uniformly distributed side alkyl content, which reduces its crystallization and deformation and increases its elasticity. When it is used to prepare TPV, it can obtain good comprehensive physical properties and processing properties.

[0020] The polymer units in the EPBR of this invention exhibit a random distribution, which can effectively reduce the crystallinity of the polymer, giving it characteristics such as low crystallinity and low deformation.

[0021] The unsaturation degree of the EPBR of the present invention is best controlled strictly between 2.5% and 5.5% (mol). If the unsaturation degree is too high, the rubber vulcanizes quickly and has poor anti-aging properties. If the unsaturation degree is too low, the rubber crosslinking density is low and the strength is low.

[0022] As a preferred embodiment, when R1 and R2 are selected from C1 to C3 alkyl groups, the alkyl group can be a straight-chain alkyl group or a branched-chain alkyl group, such as methyl, ethyl, propyl, isopropyl, etc.

[0023] As a preferred option, Ar can be phenyl, or phenyl containing conventional substituents such as methyl, ethyl, methoxy, etc.

[0024] As a preferred embodiment, when R3 and R4 are selected from C1 to C3 alkyl groups, the alkyl group can be a straight-chain alkyl group or a branched-chain alkyl group, such as methyl, ethyl, propyl, isopropyl, etc.

[0025] As a preferred embodiment, the Mooney viscosity ML of the polyethylene-propylene-butene rubber is... 100 °C = 65–80, Molecular weight distribution index M w / M n Greater than 1.8, crystallinity <12.

[0026] This invention also provides a method for preparing polyethylene-propylene-butene rubber. The method involves heating a polymerization solution system containing a structure modifier to the temperature required for initiating polymerization, then continuously and uniformly adding olefin monomers and alkyl lithium to initiate and carry out the polymerization reaction. After the olefin monomers and alkyl lithium are completely added, divinylbenzene is immediately added to continue the polymerization reaction, resulting in a polymer solution. The polymer solution is then subjected to a catalytic hydrogenation reaction to obtain the final product.

[0027] As a preferred embodiment, the structure modifier includes at least one difunctional ether selected from tetrahydrofurfuryl ethyl ether, bistetrahydrofurfuryl propane, tetrahydrofurfuryl butyl ether, and tetrahydrofurfuryl ethyl ether. As a preferred embodiment, the concentration of the structure modifier in the polymerization solution system is 15–180 mg / kg solvent. The preferred structure modifier and dosage can control the content of 1,2-polymerization or 3,4-polymerization units of the conjugated diene monomer within an appropriate proportional range, thereby adjusting the content of side alkyl and side vinyl groups.

[0028] As a preferred embodiment, the olefin monomer includes conjugated diene monomers, or conjugated diene monomers and arylethylene monomers;

[0029] The conjugated diene monomers include and / or

[0030] The aryl vinyl monomers include

[0031] R5 is selected from hydrogen, C1-C3 alkyl or vinyl groups; Ar is selected from phenyl or substituted phenyl groups.

[0032] The most preferred olefin monomers are at least one of butadiene, isoprene, isoprene, 1,3,5-hextriene, styrene, and p-alkylstyrene.

[0033] As a preferred embodiment, the olefin monomer and alkyl lithium are continuously and uniformly added to the polymerization solution system over 30–40 minutes. The alkyl lithium is commonly n-butyllithium. The amount of alkyl lithium added relative to the olefin monomer (or polymer) is 8–12 mmol / kg.

[0034] As a preferred embodiment, the initiation temperature of the polymerization reaction is 50-55°C, and the maximum temperature does not exceed 65°C.

[0035] As a preferred embodiment, the polymerization reaction continues for 12 to 20 minutes after the addition of the divinylbenzene.

[0036] As a preferred embodiment, the conditions for the catalytic hydrogenation reaction are as follows: dimethyl phthalate as a co-catalyst, dicyclopentadiene titanium dichloride as the main catalyst, hydrogen pressure of 10-13 bar, temperature of 70-120°C, and the hydrogenation endpoint is a polymer unsaturation of 2.5-5.5%.

[0037] As a preferred embodiment, the amount of the main catalyst added relative to the polymer solution is 5.0 to 6.0 mmol / kg, and the molar ratio of the main catalyst to the co-catalyst is 7 to 10.

[0038] The preferred dicyclopentadiene-titanium dichloride catalytic system for hydrogenation of polymer solutions effectively controls the degree of hydrogenation or unsaturation, preventing the complete hydrogenation of double bonds in the polymer solution. Furthermore, it allows for selective hydrogenation of conjugated dienes with five or more carbon atoms due to steric hindrance, ensuring a suitable degree of unsaturation in the hydride. In contrast, using common nickel-based catalysts for hydrogenation presents challenges such as difficult catalyst removal, high cost, and the tendency to completely hydrogenate the polymer into saturated carbon-carbon chains, thus eliminating sulfur crosslinking points.

[0039] As a preferred embodiment, the amount of divinylbenzene added relative to the olefin monomer is 0.50–0.75 g / kg. Introducing a small amount of divinylbenzene can broaden the molecular weight distribution of the polymer and provide branched long chains.

[0040] The preparation method of EPBR of the present invention includes the following specific steps: A cyclohexane solution containing a quantitative amount of structure modifier is added to a clean steel polymerization reactor. The solution is then heated to 50-55°C. Over a period of 30-40 minutes, olefin monomers and n-butyllithium (NBL) are continuously and uniformly added to the polymerization reactor. Immediately after the monomers are added, a cyclohexane solution of DVB is rapidly added within 1 minute, and the reaction continues for a certain period of time to obtain a polymer solution. The solution is hydrogenated under a catalyst composed of methyl phthalate and dicyclopentadiene titanium dichloride at 70-120°C and 10-13 bar hydrogen pressure for a certain period of time until the unsaturation of the polymer is 2.5-5.5%, at which point hydrogenation is stopped. Finally, after the hydrogenation of the solution is terminated, a small amount of antioxidant is added, followed by coagulation, dehydration, and drying to obtain block EPBR raw rubber.

[0041] The present invention also provides an application of polyethylene-propylene-butene rubber in TPV sealing materials.

[0042] As a preferred embodiment, the TPV sealing material includes polyethylene-propylene-butene rubber, PP, and auxiliary materials.

[0043] As a preferred embodiment, the TPV sealing material comprises the following components in parts by weight: 100 parts polyethylene-propylene-butene rubber, 70-80 parts PP, 80-90 parts softening filler oil, 70-90 parts inorganic filler, 2-4 parts organic peroxide, 1.5-3 parts crosslinking agent, 1.0-1.2 parts accelerator, 1.5-1.8 parts sulfur, and 0.2-0.3 parts antioxidant.

[0044] The PP / EPBR-TPV (TPV for short) sealing material of the present invention is made into granules by dynamic vulcanization of EPBR, PP and auxiliary materials including white oil and inorganic fillers, and then extruded into shape by an extruder.

[0045] In the TPV sealing material of the present invention, EPBR is the dispersed phase and serves as the soft segment of the TPV sealing material, PP is the continuous phase and serves as the hard segment of the TPV sealing material, softening filler oil is used to fill the EPBR vulcanization crosslinking network, inorganic fillers include inorganic fillers such as light calcium carbonate and inorganic lubricating fillers such as talc, crosslinking agent is used to improve crosslinking density, accelerator and sulfur are used as reinforcing vulcanizing agents, and organic peroxide is used as the vulcanizing agent for EPBR.

[0046] As a preferred embodiment, the PP is preferably injection-molded / blow-molded transparent polypropylene, such as at least one of commercially available B4902, B4808, and K4912. The preferred mass ratio of PP to polyethylene-propylene-butene rubber in the sealing strip formulation is 70-80:100. If the PP content is too low, the TPV strength will be low; if the PP content is too high, the TPV hardness and compression set will be high.

[0047] As a preferred option, the softening filler oil is selected from softening oils known to those skilled in the art, preferably paraffinic white oils, such as at least one of commercially available white oils such as 46#, 32#, 400N and 320#.

[0048] As a preferred embodiment, the inorganic filler comprises light calcium carbonate and talc, wherein the light calcium carbonate is a metal-free skeleton filler, and its preferred dosage is 0.5 to 0.6 times the mass of EPBR. The preferred talc is of 3 to 5 micrometer size, and its preferred dosage is 0.2 to 0.3 times the mass of EPBR.

[0049] As a preferred embodiment, the organic peroxide is at least one of bis-tert-butyl peroxide (BIBP), cumene peroxide (DCP), cumene hydroperoxide, and p-menthane peroxide, with BIBP and DCP being the most preferred.

[0050] As a preferred embodiment, the crosslinking agent is preferably TAIC, and the preferred dosage is 0.015 to 0.03 times the mass of EPBR. The dosage should not be too high, otherwise the crosslinking density will be too high or the EPBR will gel, affecting the overall physical properties of TPV. If the dosage is too low, the crosslinking strength will be reduced.

[0051] As a preferred option, the antioxidant can be an amine or phenolic antioxidant. EPBR has the function of resisting heat aging, but PP has poor light aging performance. Therefore, in this invention and TPV, phenolic antioxidants such as 1076 or 1010 are preferred.

[0052] As a preferred embodiment, the accelerator is preferably a dialkylthiuram-based accelerator that can rapidly release sulfur at high temperatures, such as accelerator TMTD.

[0053] The peroxide in the TPV sealing material of this invention is the main substance that initiates EPBR crosslinking. It can break the double bonds in EPBR to produce crosslinking. Accelerators and sulfur have a slower vulcanization rate for rubber with low unsaturation. Adding a small amount of accelerator and sulfur to TPV can further enhance the micro-crosslinking of EPBR. Furthermore, after extrusion TPV products (sealing strips) are formed, they can still slowly crosslink at room temperature, which can improve the strength and compression deformation of the products.

[0054] The TPV or sealing strip of the present invention can be colored with commercially available inorganic or organic masterbatches known to those skilled in the art, such as carbon black, scarlet, ultramarine, etc.

[0055] The method for preparing TPV sealing material granules according to the present invention is as follows: The materials in the formulation of the present invention are fed into a mixing mixer or internal mixer for mixing or internal mixing. Then, the mixture or masterbatch is fed into a twin-screw extruder and subjected to mixing, vulcanization crosslinking, extrusion, and pelletizing at 160–190°C to obtain TPV granules. Preferably, the mixing (or internal mixing) temperature is 30–170°C, the mixing or internal mixing time is not less than 5 minutes, the twin-screw extrusion temperature is 160–190°C, and the mixing and extrusion time of the materials in the twin-screw is not less than 3 minutes.

[0056] The TPV sealing material granules of the present invention have a melt flow index (MFR) of 3-5 g / min at 230°C, a 100% tensile strength > 2.8 MPa, a 300% tensile strength > 4.0 MPa, a tensile strength > 6.5 MPa, an elongation at break > 500%, a tear strength > 40 KN / m, a hardness of 58-62 A, and a deformation < 90%.

[0057] The method for preparing sealing strips from TPV sealing material of the present invention is as follows: TPV granules are fed into a twin-screw extruder and extruded at 160-190°C. Different types of shaped sealing strips can be extruded according to different profile dies. After cooling and shaping, the sealing strips are obtained.

[0058] Compared with existing technologies, the beneficial effects of the technical solution of this invention are as follows:

[0059] The existing EPDM contains vanadium residue, which has a catalytic aging effect in the finished product. At the same time, EPDM has high preparation cost, and TPV prepared by combining EPDM with polypropylene (PP) has defects such as large compression deformation, small defects on the product surface, uneven surface, lack of matte finish and dullness.

[0060] The PP / EPBR-TPV prepared using EPBR provided by this invention has advantages such as high strength, good elasticity, low deformation, easy injection molding, glossy and full surface of the product, and heat resistance and aging resistance. This is mainly due to the fact that PP and EPBR in the TPV sealing material do not undergo phase separation; that is, both PP and EPBR contain homologous structures derived from carbon and hydrogen atoms such as ethylene, methylene, and methyl groups, exhibiting good compatibility. Furthermore, vulcanization crosslinking mainly occurs between EPBR molecules, forming a network of large EPBR molecules. Under strong mixing, these form fine elastic rubber particles dispersed in the polypropylene (melt), dispersing PP into a continuous phase. The crosslinked EPBR network forms a 3-5 micrometer dispersed phase, locking the softening oil to form a soft, elastic rubber phase. In other words, the continuous PP phase and the oil-filled crosslinked EPBR network form an "island" structure, creating a stable physical junction (or physical crosslinking point). In addition, EPBR has a suitable and uniformly distributed side group content, reducing material crystallization and deformation, and increasing the material's elasticity. Overall, this gives the TPV sealing material excellent comprehensive physical and processing properties.

[0061] The EPBR selected in this invention is used as a TPV sealing strip, which retains the original behavior of PP / EPDM-TPV and also has the advantages of good overall performance and low manufacturing cost.

[0062] The EPBR of this invention allows for complete monomer conversion during preparation, is low-cost, and simple to operate, eliminating the need for vanadium-based catalysts that undergo catalytic aging, which is beneficial for industrial production.

[0063] The method of using EPBR to prepare TPV sealing materials according to the present invention is simple, can be produced using existing mature processes, and is easy to control and industrialize.

[0064] The PP / EPBR-TPV preparation method of the present invention uses polyethylene-propylene-butene ternary rubber (EPBR) and fillers such as PP to prepare the PP / EPBR-TPV through co-vulcanization. It is used as a sealing strip, which avoids the shortcomings and drawbacks of the existing PP / EPDM-TPV sealing strip, as well as the defects of the existing SEBS / PP alloy, such as stickiness after oil filling, poor heat resistance, large deformation, and easy breakage due to phase separation. Attached Figure Description

[0065] Figure 1 H, the source of EPBR raw rubber, Example 1# 1 -NMR.

[0066] Figure 2 Example 1# hydrogenated EPBR-1# is the source of the original rubber. 1 -NMR. Detailed Implementation

[0067] 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.

[0068] 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; the Mooney viscosity of the raw rubber was determined according to GB1232 standard.

[0069] Example of EPBR source preparation:

[0070] Example 1

[0071] Under nitrogen protection, 0.5 mL of a 50% tetrahydrofurfuryl ether (ETE) cyclohexane solution and 3500 mL of cyclohexane were added to a 5L polymerization reactor. Stirring was started, and the material temperature was raised to 50°C. Then, 3.0 mL of 0.65 mol / L NBL and a mixed monomer consisting of 360 mL butadiene and 25 mL isoprene were continuously added to the reactor over a period of 30 min. Immediately after the addition of all materials, 2.2 mL of a 10% divinylbenzene cyclohexane solution was added to the reactor, and polymerization continued for another 18 min, maintaining the polymerization temperature below 65°C. This yielded EPBR raw rubber solution #1. EPBR raw rubber #1H 1 -NMR spectrum see Figure 1 .

[0072] Next, 8 mL of a 0.02 mol / L cyclohexane solution of dimethyl phthalate and methyl o-methyl benzoate, and 0.3 g of titanium dichloride dicyclopentadiene were added to the gel solution. Catalytic hydrogenation was carried out at 100 °C and 13 bar hydrogen pressure for 95 min, after which hydrogenation was stopped. The gel solution was then subjected to water termination, coagulation, dehydration, and drying to obtain 356 g of granular EPBR raw rubber (monomer conversion rate 100%), labeled as EPBR-1#, with a H... 1 -NMR spectrum see Figure 2 The technical specifications of its hydrogenated gel are shown in Table 1.

[0073] Example 2

[0074] The process conditions of Example 1 were kept unchanged, except that 350 mL of butadiene, 20 mL of isoprene, 0.4 mL of tetrahydrofurfuryl ether, 3.5 mL of NBL, and 2.5 mL of a cyclohexane solution of DVB were added. The resulting hydrogenated gel was labeled EPBR-2#, and the polymer behavior analysis is shown in Table 1.

[0075] Example 3

[0076] The process conditions in Example 1 were kept unchanged, except that 370 mL of butadiene, 25 mL of 1,3,5-hextriene, 0.6 mL of bis(tetrahydrofurfuryl)propane, 3.0 mL of NBL, and 3 mL of DVB in cyclohexane solution were added. The hydrogenation pressure in the hydrogenation unit was 13 bar, and the hydrogenation time was 90 min. The resulting raw rubber was labeled EPBR-3#, and the polymer behavior analysis is shown in Table 1.

[0077] Example 4

[0078] The process conditions in Example 1 were kept unchanged, except that the added butadiene was 360 mL, styrene 30 mL, tetrahydrofurfuryl ether 0.2 mL, NBL 3.2 mL, DVB cyclohexane solution 1.7 mL, and the NBL and monomer addition time was 40 min. The hydrogenation unit had a hydrogenation pressure of 13 bar and a hydrogenation time of 90 min. The resulting raw rubber was labeled EPBR-4#, and the polymer behavior analysis is shown in Table 1.

[0079] Example 5

[0080] The process conditions in Example 1 were kept unchanged, except that the following were added: 340 mL of butadiene, 30 mL of styrene, 20 mL of isoprene, 0.18 mL of tetrahydrofurfuryl ethyl ether, 2.8 mL of NBL, 1.6 mL of cyclohexane solution of DVB, and the addition time of NBL and monomers was 40 min. The hydrogenation unit was operated at a hydrogenation pressure of 13–14 bar for 90 min. The resulting raw rubber was labeled EPBR-5#, and the polymer behavior analysis is shown in Table 1.

[0081] Example 6

[0082] The relevant process conditions in Implementation 1 are kept unchanged, except that 360 mL of butadiene and 45 mL of isoprene are added, and NBL is added to the polymerization reactor all at once, with a hydrogenation time of 120 min.

[0083] The resulting raw rubber was labeled EPBR-6#, and the behavior analysis of the polymer is shown in Table 1.

[0084] Table 1. Characteristic analysis of polymers and commercially available EPDM in examples of EPBR raw material sources.

[0085]

[0086] Note: The Mooney viscosity of DOW 4770 and Mitsui 3112 was tested at 125°C, while that of other polymers was tested at 100°C.

[0087] TPV Preparation Examples

[0088] The EPBR-1#, EPBR-2#, EPBR-3#, EPBR-4#, EPBR-5#, and EPBR-6# raw rubbers in Table 1, along with commercially available Mitsui 4045, Mitsui 3112, and DOW4770 raw rubbers, were compounded according to the TPV preparation method described in this invention. Specifically, Mitsui 4045 and EPBR-3# were compounded and vulcanized in an internal mixer at 60-170°C for 8 minutes. The resulting masterbatch was then calendered into strips on a twin-roll calender at 115-120°C. Other samples were mixed in a blender at 30-60°C for 5 minutes. The masterbatch strips and compounded rubbers were then fed into a twin-screw extruder at 160-190°C for 3-5 minutes for mixing, vulcanization, crosslinking, extrusion, and pelletizing to obtain TPV pellets. The formulations for each sample number are shown in Table 2, and the physical properties of TPV granules or extruded sealing strips are shown in Table 3.

[0089] Table 2. Formulation of TPV granules or extruded sealing strips (parts by weight)

[0090]

[0091]

[0092] Note: The dosage of other minor ingredients in the formula, such as antioxidants and colorants, may be adjusted according to the dosages commonly known to industry professionals.

[0093] Table 3 Physical Properties of TPV Sealing Strips

[0094]

[0095] Table 3 shows that the TPV made from EPBR and PP of this invention exhibits excellent overall physical properties. However, the TPV made from EPBR-6# adhesive with excessively high unsaturation and a narrow polymer molecular weight distribution has poor physical properties, especially poor anti-aging properties.

Claims

1. A polyethylene-propylene-butene rubber, characterized by: has the following structural expression: ； wherein, R1 and R2 are independently selected from hydrogen or C1-C3 alkyl; R3 and R4 are independently selected from hydrogen, C1-C3 alkyl or vinyl; Ar is phenyl or substituted phenyl; x, n, y, m and z are polymerization degrees, x, n, y, m and z are all greater than or equal to 0, and the sum of x, n, y and m is greater than 0, (x+y+z) / (m+n)=17-38; The iodine value unsaturation of the polyethylene-propylene-butylene rubber is 2.5-5.5%, and the mass ratio of side alkyl chain is 28-60%.

2. The polyethylene-propylene-butylene rubber according to claim 1, characterized in that: The polyethylene-propylene-butylene rubber has a Mooney viscosity ML 100℃ = 65 ~ 80, a molecular mass distribution index M w / M n greater than 1.8, a crystallinity < 12.

3. A process for the preparation of a polyethylene-propylene-butene rubber according to claim 1 or 2, characterized in that: After the polymerization solution system containing the structure regulator is heated to the temperature required for initiating polymerization, the olefin monomer and the alkyl lithium are continuously and uniformly added to initiate and carry out polymerization reaction, and after the addition of the olefin monomer and the alkyl lithium is completed, the divinylbenzene is immediately added to continue the polymerization reaction, so as to obtain the polymer glue solution; and the polymer glue solution is subjected to catalytic hydrogenation reaction, so as to obtain the product.

4. The method for preparing polyethylene-propylene-butene rubber according to claim 3, characterized in that: The structure regulator includes at least one of tetrahydrofurfuryl alcohol diethyl ether, ditetrahydrofurfuryl propane, tetrahydrofurfuryl alcohol butyl ether and tetrahydrofurfuryl alcohol hexyl ether difunctional ether.

5. A process for the preparation of a polyethylene-propylene-butene rubber according to claim 3 or 4, characterized in that: The concentration of the structure regulator in the polymerization solution system is 15-180 mg / kg of solvent.

6. The preparation method of the polyethylene-propylene-butylene rubber according to claim 3, characterized in that: The olefin monomer includes a conjugated diene monomer, or a conjugated diene monomer and an aryl ethylene monomer; The conjugated diene-based monomer includes and / or ; The arylethylene monomers include ; wherein, R5 is selected from hydrogen, C1-C3 alkyl or vinyl; Ar is selected from phenyl or substituted phenyl.

7. The method for preparing polyethylene-propylene-butene rubber according to claim 3, characterized in that: The olefin monomer and the alkyl lithium are continuously and uniformly added to the polymerization solution system within 30-40 min.

8. The method for preparing polyethylene-propylene-butene rubber according to claim 3, characterized in that: The initiation temperature of the polymerization reaction is 50-55 ℃, and the maximum temperature is not higher than 65 ℃.

9. The method for preparing polyethylene-propylene-butene rubber according to claim 3, characterized in that: The time for continuing the polymerization reaction after the addition of the divinylbenzene is completed is 12-20 min.

10. The method for preparing polyethylene-propylene-butene rubber according to claim 3, characterized in that: The catalytic hydrogenation reaction is carried out under the following conditions: dimethyl phthalate is used as a cocatalyst, dicyclopentadiene titanium dichloride is used as a main catalyst, the hydrogen pressure is 10-13 bar, the temperature is 70-120 ℃, and the hydrogenation end point is that the unsaturation of the polymer is 2.5-5.5%.

11. The preparation method of the polyethylene-propylene-butylene rubber according to claim 10, characterized in that: The addition amount of the main catalyst relative to the polymer glue solution is 5.0-6.0 mmol / kg, and the molar ratio of the main catalyst / cocatalyst is 7-10.

12. Use of a polyethylene-propylene-butylene rubber according to claim 1 or 2, characterized in that: It is applied to a TPV sealing material.

13. Use of a polyethylene-propylene-butylene rubber according to claim 12, characterized in that: The TPV sealing material includes polyethylene-propylene-butylene rubber, PP and auxiliary materials.

14. Use of a polyethylene-propylene-butylene rubber according to claim 13, characterized in that: The TPV sealing material includes the following components by mass: 100 parts of polyethylene-propylene-butylene rubber, 70-80 parts of PP, 80-90 parts of softening filling oil, 70-90 parts of inorganic filler, 2-4 parts of organic peroxide, 1.5-3 parts of crosslinking agent, 1.0-1.2 parts of accelerator, 1.5-1.8 parts of sulfur and 0.2-0.3 parts of antioxidant.

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