An ethylene-propylene-acrylate polymer and a method of making

Abstract

The application provides a preparation method of an ethylene-propylene-acrylate polymer, which comprises the following steps: (1) mixing polyethylene oligomer, polypropylene oligomer and acrylic functional monomer in a reaction screw extruder to obtain a first mixture; (2) adding an initiator into the first mixture in the reaction screw extruder to perform copolymerization and obtain a second mixture; and (3) adding a termination agent into the second mixture in the reaction screw extruder to perform reaction termination and obtain the ethylene-propylene-acrylate polymer. The polyethylene oligomer, the polypropylene oligomer and the acrylic functional monomer are copolymerized under the action of the initiator, and then the polymerization reaction is terminated through the termination agent, and finally the ethylene-propylene-acrylate polymer is prepared. The product can obviously improve the low-temperature resistance, high-temperature resistance, oil resistance and aging resistance of the material, and can be used to replace fluororubber for low-temperature oil-resistant products.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to a method for preparing an ethylene-propylene-acrylate polymer. Background Technology

[0002] Ethylene-acrylate copolymers have long been important materials in the field of specialty elastomers due to their good processing characteristics, excellent oil resistance, and good temperature resistance. However, copolymerization of ethylene with other functional monomers requires high-temperature, high-pressure solution polymerization or emulsion polymerization, which places high demands on equipment and makes it difficult to reduce polymerization costs. Reactive grafting can improve the oil and heat resistance of polyethylene, but reactive grafting is limited by the reactive sites, resulting in poor product quality stability.

[0003] CN202111044895.5 discloses an ethylene-acrylate copolymer and its preparation method. The preparation method includes the following steps: (1) mixing an aqueous solution containing an emulsifier with methyl acrylate and a functional monomer to obtain a first solution; (2) mixing the first solution with an initiator to obtain a second solution, and reacting it with ethylene to obtain a reaction solution; (3) demulsifying, filtering, and drying the reaction solution with a methanol solution containing hydroquinone. The method of the present invention has the advantages of simple and mild preparation conditions, and the use of water as a medium can reduce pollution. This invention uses an emulsion instead of a solution to reduce the reaction conditions of ethylene-acrylate polymerization, resulting in lower reaction temperature and pressure for the copolymerization of ethylene and acrylate, and relatively simplified post-processing. CN202211156394.0 relates to an ethylene-acrylate graft polymer modifier. Specifically, during the extrusion of ethylene-acrylate (AEM) in a twin-screw extruder, a group of functional monomers with synergistic effects are added: 1,3-bis(methacryloyloxy)-2-trimethylsiloxypropane and N-isopropyl-N-benzyl-2-acrylamide. Under the action of initiator DCP and co-crosslinking agent TAIC, a grafting reaction occurs on the ethylene-acrylate (AEM) molecular chain, resulting in an ethylene-acrylate (AEM) graft polymer with unique conformational flexibility, excellent heat resistance, and aging resistance. This graft polymer has good compatibility with propylene and can improve the aging resistance of polypropylene. CN202210059637.2 discloses an ethylene-acrylate rubber resistant to 200℃, low pressure change, and high pulse. The technical solution includes the following components by weight: 80-120 parts ethylene-acrylate rubber, 1-3 parts stearic acid, 1-3 parts liquid antioxidant, 1.5-4.5 parts additives, 50-80 parts carbon black, 20-40 parts functional reinforcing agent, 10-30 parts novel high-temperature resistant plasticizer, and 2-6 parts crosslinking agent. The advantages of this invention are: optimized rubber formulation, effective capture of oxygen free radicals, prevention of free radical damage to polymer molecular structure and polymer degradation, better compatibility between liquid oxidant and rubber, and the heating of ceramic micropowder facilitates the bonding of rubber with carbon black and various additives, greatly improving the service life of turbocharger pipes under extreme conditions and enhancing the safety and practicality of the turbocharger hot-end pipe assembly. CN201310511444.7 relates to a cable material, specifically a high heat- and oil-resistant ethylene-acrylate rubber cable material. This cable material comprises the following raw materials in parts by weight: ethylene-acrylate rubber, carbon black, fluororubber, polystyrene, triallyl isocyanate, accelerator, zinc stearate, carbon black, silica, dibutyl maleate, dioctyl tin di-n-thioglycolic acid, dibasic lead phosphite, silane coupling agent, crosslinking agent, diethylene glycol benzoate, and other additives.This cable material combines the advantages of ethylene-acrylate rubber, fluororubber, and polystyrene, improving the performance of traditional ethylene-acrylate rubber cable materials. It possesses superior high-temperature and oil resistance, making it suitable for specific operating environments, especially high-temperature and high-oil environments, and has broad market application prospects.

[0004] Existing technologies typically involve reducing reaction conditions through solution polymerization or preparing ethylene-acrylate polymer materials with good compatibility with polypropylene, high temperature resistance, and oil resistance through reactive grafting and physical blending. However, ethylene-acrylate polymer materials prepared using existing technologies lose their rubber elasticity at low temperatures, ultimately leading to the failure of rubber products. This invention combines the aforementioned reaction mechanism, using ethylene oligomers, propylene oligomers, and acrylic functional monomers, which undergo melt polymerization under the action of an initiator, further terminating to obtain an ethylene-propylene-acrylate copolymer. This invention solves the problems of poor low-temperature resistance, high-temperature resistance, oil resistance, and aging resistance in existing ethylene-acrylate polymer preparations. This product can replace fluororubber for use in low-temperature, oil-resistant products, and the technical route and preparation method have not been reported in the literature. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing an ethylene-propylene-acrylate polymer. In a reactive screw extruder, an initiator is used to initiate the polymerization of functional monomers of ethylene, propylene, and acrylic acid. After the reaction is complete, a terminator is used to terminate the reaction, ultimately preparing the ethylene-propylene-acrylate polymer. This material can improve the low-temperature resistance, high-temperature resistance, oil resistance, and aging resistance of products, and can replace fluororubber for use in low-temperature oil-resistant products.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing an ethylene-propylene-acrylate polymer, wherein the raw materials for preparing the ethylene-propylene-acrylate polymer include, by weight: 25-55 (preferably 28-50) parts of polyethylene oligomer, 15-45 (preferably 18-40) parts of polypropylene oligomer, 15-55 (preferably 17-53) parts of acrylic functional monomer, 0.03-0.2 parts of initiator and 0.3-1.5 parts of terminator.

[0008] The "low temperature resistance" mentioned in this invention refers to a temperature range of -20 to 40°C, such as -20°C, -30°C, -40°C, and specific values ​​between these values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific values ​​included in the range.

[0009] The "high temperature resistance" mentioned in this invention refers to a temperature range of 150-230℃, such as 150℃, 170℃, 200℃, 230℃, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific values ​​included in the range.

[0010] The polyethylene oligomer in this invention is 25-55 parts by weight, for example, 25 parts, 35 parts, 40 parts, 45 parts, 55 parts, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0011] The polypropylene oligomer in this invention is 15-45 parts by weight, for example, 15 parts, 25 parts, 30 parts, 35 parts, 45 parts, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0012] The acrylic functional monomers described in this invention are in the range of 15-55 parts by weight, for example, 15 parts, 20 parts, 30 parts, 40 parts, 45 parts, 55 parts, and specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0013] The initiator described in this invention is 0.03-0.2 parts by weight, for example, 0.03 parts, 0.10 parts, 0.12 parts, 0.2 parts, and specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0014] The terminating agent described in this invention is 0.3-1.5 parts by weight, for example, 0.3 parts, 0.7 parts, 0.75 parts, 0.8 parts, 1.5 parts, and specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0015] The polyethylene oligomers described in this invention are low molecular weight homopolymers of ethylene polymerized by solution polymerization, including any one or a combination of at least two of linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), and polyethylene wax.

[0016] The polypropylene oligomer described in this invention is obtained by thermal cracking of high molecular weight polypropylene and is a crystalline waxy or soft waxy solid. Brand: WAX wax;

[0017] The acrylic functional monomers described in this invention are compounds containing hydroxyl groups and acrylates, including any one or a combination of at least two of 2-(hydroxymethyl)acrylate, hydroxyethyl acrylate (HEA), hydroxyethyl methacrylate (HEMA), hydroxypropyl acrylate (HPA), hydroxypropyl methacrylate (HPMA), polyethylene glycol monomethacrylate (HEMA-5), phenyl glycidyl ether acrylate (PGEA), and 2-hydroxy-3-phenoxypropyl acrylate;

[0018] The initiator described in this invention includes any one or a combination of at least two of benzoyl peroxide (BPO), dicumyl peroxide (DCP), tert-butyl peroxide, and tert-butyl peroxide-2-ethylhexanoate (TBPO);

[0019] The terminating agent described in this invention includes any one or a combination of at least two of hydroquinone, p-tert-butylcatechol, and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate];

[0020] In a second aspect, the present invention provides a method for preparing an ethylene-propylene-acrylate polymer as described in the first aspect, the method comprising:

[0021] An initiator is used to initiate the melt polymerization of ethylene, propylene, and acrylic acid functional monomers, and then a terminator is used to terminate the reaction, ultimately preparing an ethylene-propylene-acrylate polymer.

[0022] Preferably, the preparation method specifically includes:

[0023] (1) In a reactive screw extruder, polyethylene oligomer, polypropylene oligomer and acrylic functional monomer are mixed to obtain a first mixture;

[0024] (2) In a reactive screw extruder, an initiator is added to the first mixture to copolymerize and obtain a second mixture;

[0025] (3) In a reactive screw extruder, a terminator is added to the second mixture to terminate the reaction and obtain an ethylene-propylene-acrylate polymer.

[0026] Step (1) is mainly to mix polyethylene oligomer, polypropylene oligomer and acrylic functional monomer evenly, so as to facilitate the reverse polymerization reaction; Step (2) is to copolymerize in a reactive screw extruder to allow it to react fully; Step (3) is to terminate the ethylene-propylene-acrylate polymer, mix the polymer and the terminator evenly, and prepare the final product.

[0027] In step (1) of this invention, the reaction screw extruder mixing temperature is 125-190°C, for example, it can be 125°C, 140°C, 150°C, 160°C, 170°C, 190°C, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0028] In step (1) of this invention, the reaction screw extruder mixing speed is 15-70 rpm, for example, it can be 15 rpm, 20 rpm, 20 rpm, 40 rpm, 70 rpm, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0029] In this invention, the reaction screw extruder mixing in step (1) has a reaction time of 0.5 to 4.5 minutes, for example, 0.5 minutes, 1.5 minutes, 2 minutes, 4.5 minutes, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0030] In step (2) of this invention, the reaction polymerization in the screw extruder is carried out at a reaction temperature of 95 to 170°C. For example, it can be 95°C, 110°C, 120°C, 130°C, 140°C, 150°C, 170°C, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0031] In step (2) of this invention, the reaction screw extruder reaction polymerization is performed at a speed of 5-60 rpm, for example, it can be 5 rpm, 20 rpm, 20 rpm, 40 rpm, 60 rpm, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0032] In step (2) of this invention, the reaction polymerization in the screw extruder has a reaction time of 1 to 6 minutes, for example, 1 minute, 3 minutes, 4 minutes, 6 minutes, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0033] In step (3) of this invention, the reaction of the screw extruder is terminated at a temperature of 120-160°C, for example, 120°C, 140°C, 160°C, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0034] In step (3) of this invention, the reaction of the screw extruder is terminated at a speed of 35-90 rpm, for example, it can be 35 rpm, 60 rpm, 70 rpm, 90 rpm, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0035] In this invention, the reaction of the screw extruder in step (3) is terminated in 0.5 to 3 minutes, for example, 0.5 minutes, 2 minutes, 3 minutes, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0036] In this invention, the screw extruder extrusion in steps (1), (2) and (3) is used, and the extrusion pressure is 8-25 MPa, for example, 8 MPa, 12 MPa, 15 MPa, 20 MPa, 22 MPa, 25 MPa, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0037] In this invention, polyethylene oligomers, polypropylene oligomers, and acrylic functional monomers are first mixed in a certain mass ratio using a reactive screw extruder; then an initiator is added to carry out reactive polymerization; finally, a terminator is added to terminate the reaction, yielding an ethylene-propylene-acrylate polymer. Compared to existing technologies, the product of this invention significantly improves low-temperature resistance, high-temperature resistance, oil resistance, and aging resistance.

[0038] The reactive screw extruder used in this invention is a general-purpose polymer processing equipment with a temperature control range of 30 to 350°C and a speed control range of 10 to 120 rpm. There is no specific model limit, as long as the equipment meets the requirements for safe use and can mix low molecular weight polyethylene, low molecular weight polypropylene, acrylate functional monomers, initiators and terminators evenly.

[0039] Thirdly, the present invention provides a method for preparing an ethylene-propylene-acrylate polymer as described in the first aspect.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] This invention provides a method for preparing an ethylene-propylene-acrylate polymer. Under the action of an initiator, ethylene oligomers, propylene oligomers, and acrylic functional monomers are melt-polymerized, and further terminated to obtain an ethylene-propylene-acrylate copolymer. This invention solves the problems of poor low-temperature resistance, high-temperature resistance, oil resistance, and aging resistance in existing ethylene-acrylate polymer preparation technologies. The product achieves a compression cold resistance coefficient of over 0.3 at -40℃, a temperature resistance rating of 200℃, and significantly improved and superior oil resistance and aging resistance compared to existing products. Detailed Implementation

[0042] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0043] The experimental materials used in the embodiments and comparative examples of this invention are as follows:

[0044] 25-55 (preferably 28-50) parts of polyethylene oligomer, 15-45 (preferably 18-40) parts of polypropylene oligomer, 15-55 (preferably 17-53) parts of acrylic functional monomer, 0.03-0.2 parts of initiator and 0.3-1.5 parts of terminator.

[0045] (1) Polyethylene oligomers are low molecular weight homopolymers of ethylene produced by solution polymerization. Among them, linear low-density polyethylene (LLDPE) is a product of Sinopec Qilu Petrochemical Company, grade: F182MT; low-density polyethylene (LDPE) is a product of Sinopec Maoming Petrochemical Company, grade: 2426H; and polyethylene wax is a product of Wuhan Xindongyi Chemical Co., Ltd., grade: 400PE.

[0046] (2) Polypropylene oligomers are obtained by thermal cracking of high molecular weight polypropylene and are crystalline waxy or soft waxy solids. Product of Dongguan Xingyuan Chemical Co., Ltd., brand name: WAX wax;

[0047] (3) The functional monomers of acrylic acid are compounds containing hydroxyl groups and acrylates, including methyl 2-(hydroxymethyl)acrylate, CAS No.: 15484-46-5, a product of Shanghai Aladdin Biochemical Technology Co., Ltd.; hydroxyethyl acrylate (HEA), hydroxyethyl methacrylate (HEMA), hydroxypropyl acrylate (HPA), hydroxypropyl methacrylate (HPMA), polyethylene glycol monomethacrylate (HEMA-5), and phenyl glycidyl ether acrylate (PGEA) are products of Guangzhou Jingde Chemical Materials Co., Ltd.; 2-hydroxy-3-phenoxypropyl acrylate is a product of Guangdong Wengjiang Chemical Reagent Co., Ltd.; (4) The initiators include benzoyl peroxide (BPO), dicumyl peroxide (DCP), tert-butyl peroxide and tert-butyl peroxide-2-ethylhexanoate (TBPO), products of Dalian Ruisheng Rubber & Plastic Materials Co., Ltd.;

[0048] (5) The terminator is a phenolic terminator, including hydroquinone, p-tert-butylcatechol and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], a product of Dalian Ruisheng Rubber & Plastic Materials Co., Ltd.

[0049] Example 1

[0050] This embodiment provides a method for preparing an ethylene-propylene-acrylate polymer, the components of which, by weight, include: 30 parts of linear low-density polyethylene (LLDPE) with a weight average molecular weight of 18.76 × 10⁻⁶. 4 20 parts polypropylene WAX ​​wax (weight average molecular weight: 5637 g / cm³), 50 parts methyl 2-(hydroxymethyl)acrylate, 0.05 parts benzoyl peroxide (BPO), and 0.5 parts hydroquinone.

[0051] This embodiment also provides a preparation step for an ethylene-propylene-acrylate polymer, the preparation step including:

[0052] (1) In a reactive screw extruder, polyethylene oligomer, polypropylene oligomer and acrylic functional monomer are mixed. The extruder mixing temperature is 130°C, the mixing speed is 20 rpm, the mixing time is 3 minutes, and the mixture is extruded at an extrusion pressure of 20 MPa to obtain the first mixture.

[0053] (2) In a reaction screw extruder, an initiator is added to the first mixture for copolymerization. The reaction temperature of the reaction screw extruder is 100°C, the reaction speed is 10 rpm, the reaction time is 5 minutes, and the extrusion is carried out at an extrusion pressure of 20 MPa to obtain the second mixture.

[0054] (3) In a reaction screw extruder, the terminator is added to the second mixture to terminate the reaction. The termination temperature of the reaction screw extruder is 130°C, the termination speed is 40 rpm, the termination process lasts for 2 minutes, and the extrusion is carried out at an extrusion pressure of 20 MPa to obtain an ethylene-propylene-acrylate polymer.

[0055] (4) In a closed rubber mixing mill, ethylene-propylene-acrylate polymer, stearic acid, zinc oxide, vulcanization accelerator HVA2, vulcanizing agent bis 2-5, carbon black N330, carbon black N660, antioxidant RD, and paraffin oil 2280 are added sequentially in a mass ratio of 100.0:0.5:4.0:1.5:2.0:35.0:40.0:1.0:15.0 for mixing. During mixing, the temperature of the closed rubber mixing mill is 70℃, the speed is 60 rpm, and after mixing for 8 minutes, the top bolt is opened to discharge the rubber and obtain the mixed rubber. The mixed rubber is then added to... The ethylene-propylene-acrylate polymer sample (compression cold resistance coefficient and volume change rate: cylinder with a diameter of 10 mm ± 0.2 mm and a height of 10 mm ± 0.2 mm; temperature resistance grade and aging coefficient: sample size of 150 mm ± 0.5 mm × 150 mm ± 0.5 mm) was vulcanized in a hot oil press at a temperature of 160℃ and a pressure of 10 MPa for 15 min. The test results are shown in Table 1.

[0056] Example 2

[0057] This embodiment provides a method for preparing an ethylene-propylene-acrylate polymer, the components of which, by weight, include: 50 parts of low-density polyethylene (LDPE, weight average molecular weight: 9.27 × 10⁻⁶). 4 40 parts polypropylene WAX ​​wax (weight average molecular weight: 8216 g / cm³), 10 parts hydroxyethyl acrylate (HEA), 0.15 parts dicumyl peroxide (DCP), and 1 part p-tert-butylcatechol.

[0058] This embodiment also provides a preparation step for an ethylene-propylene-acrylate polymer, the preparation step including:

[0059] (1) In a reactive screw extruder, polyethylene oligomer, polypropylene oligomer and acrylic functional monomer are mixed. The extruder mixing temperature is 180℃, the mixing speed is 60 rpm, the mixing time is 1 minute, and the mixture is extruded at an extrusion pressure of 10 MPa to obtain the first mixture.

[0060] (2) In a reaction screw extruder, an initiator is added to the first mixture for copolymerization. The reaction temperature of the reaction screw extruder is 160°C, the reaction speed is 50 rpm, the reaction time is 2 minutes, and the extrusion is carried out at an extrusion pressure of 10 MPa to obtain the second mixture.

[0061] (3) In a reaction screw extruder, the terminator is added to the second mixture to terminate the reaction. The termination temperature of the reaction screw extruder is 150°C, the termination speed is 80 rpm, the reaction time is 1 minute, and the extrusion is carried out at an extrusion pressure of 10 MPa to obtain an ethylene-propylene-acrylate polymer.

[0062] (4) In a closed rubber mixing mill, ethylene-propylene-acrylate polymer, stearic acid, zinc oxide, vulcanization accelerator HVA2, vulcanizing agent bis 2-5, carbon black N330, carbon black N660, antioxidant RD, and paraffin oil 2280 are added sequentially in a mass ratio of 100.0:0.5:4.0:1.5:2.0:35.0:40.0:1.0:15.0 for mixing. During mixing, the temperature of the closed rubber mixing mill is 70℃, the speed is 60 rpm, and after mixing for 8 minutes, the top bolt is opened to discharge the rubber and obtain the mixed rubber. The mixed rubber is then added to... The ethylene-propylene-acrylate polymer sample (compression cold resistance coefficient and volume change rate: cylinder with a diameter of 10 mm ± 0.2 mm and a height of 10 mm ± 0.2 mm; temperature resistance grade and aging coefficient: sample size of 150 mm ± 0.5 mm × 150 mm ± 0.5 mm) was vulcanized in a hot oil press at a temperature of 160℃ and a pressure of 10 MPa for 15 min. The test results are shown in Table 1.

[0063] Example 3

[0064] This embodiment provides a method for preparing an ethylene-propylene-acrylate polymer, the components of which, by weight, include: 40 parts polyethylene wax (weight average molecular weight: 2819 g / cm³), 30 parts polypropylene WAX ​​wax (weight average molecular weight: 5372 g / cm³), 30 parts hydroxyethyl methacrylate (HEMA), 0.1 parts benzoyl tert-butyl peroxide, and 0.8 parts pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0065] This embodiment also provides a preparation step for an ethylene-propylene-acrylate polymer, the preparation step including:

[0066] (1) In a reactive screw extruder, polyethylene oligomer, polypropylene oligomer and acrylic functional monomer are mixed. The extruder mixing temperature is 150°C, the mixing speed is 40 rpm, the mixing time is 2 minutes, and the mixture is extruded at an extrusion pressure of 12 MPa to obtain the first mixture.

[0067] (2) In a reaction screw extruder, an initiator is added to the first mixture for copolymerization. The reaction temperature of the reaction screw extruder is 150°C, the reaction speed is 40 rpm, the reaction time is 3 minutes, and the extrusion pressure is 12 MPa to obtain the second mixture.

[0068] (3) In a reaction screw extruder, the terminator is added to the second mixture to terminate the reaction. The termination temperature of the reaction screw extruder is 150°C, the termination speed is 40 rpm, the reaction time is 1.5 minutes, and the extrusion is carried out at an extrusion pressure of 12 MPa to obtain an ethylene-propylene-acrylate polymer.

[0069] (4) In a closed rubber mixing mill, ethylene-propylene-acrylate polymer, stearic acid, zinc oxide, vulcanization accelerator HVA2, vulcanizing agent bis 2-5, carbon black N330, carbon black N660, antioxidant RD, and paraffin oil 2280 are added sequentially in a mass ratio of 100.0:0.5:4.0:1.5:2.0:35.0:40.0:1.0:15.0 for mixing. During mixing, the temperature of the closed rubber mixing mill is 70℃, the speed is 60 rpm, and after mixing for 8 minutes, the top bolt is opened to discharge the rubber and obtain the mixed rubber. The mixed rubber is then added to... The ethylene-propylene-acrylate polymer sample (compression cold resistance coefficient and volume change rate: cylinder with a diameter of 10 mm ± 0.2 mm and a height of 10 mm ± 0.2 mm; temperature resistance grade and aging coefficient: sample size of 150 mm ± 0.5 mm × 150 mm ± 0.5 mm) was vulcanized in a hot oil press at a temperature of 160℃ and a pressure of 10 MPa for 15 min. The test results are shown in Table 1.

[0070] Example 4

[0071] This embodiment provides a method for preparing an ethylene-propylene-acrylate polymer, the components of which, by weight, include: 35 parts of linear low-density polyethylene (LLDPE, weight average molecular weight: 14.87 × 10⁻⁶). 4 25 parts polypropylene WAX ​​wax (weight average molecular weight: 8102 g / cm³), 40 parts hydroxypropyl acrylate (HPA), 0.05 parts tert-butyl peroxide-2-ethylhexanoate (TBPO), and 0.5 parts hydroquinone.

[0072] This embodiment also provides a preparation step for an ethylene-propylene-acrylate polymer, the preparation step including:

[0073] (1) In a reactive screw extruder, polyethylene oligomer, polypropylene oligomer and acrylic functional monomer are mixed. The extruder mixing temperature is 140℃, the mixing speed is 30 rpm, the mixing time is 2 minutes, and the mixture is extruded at an extrusion pressure of 18 MPa to obtain the first mixture.

[0074] (2) In a reactive screw extruder, an initiator is added to the first mixture for copolymerization. The reaction temperature of the reactive screw extruder is 130°C, the reaction speed is 30 rpm, the reaction time is 4 minutes, and the extrusion is carried out at an extrusion pressure of 18 MPa to obtain the second mixture.

[0075] (3) In a reaction screw extruder, the terminator is added to the second mixture to terminate the reaction. The termination temperature of the reaction screw extruder is 135°C, the termination speed is 50 rpm, the reaction time is 2 minutes, and the extrusion is carried out at an extrusion pressure of 18 MPa to obtain an ethylene-propylene-acrylate polymer.

[0076] (4) In a closed rubber mixing mill, ethylene-propylene-acrylate polymer, stearic acid, zinc oxide, vulcanization accelerator HVA2, vulcanizing agent bis 2-5, carbon black N330, carbon black N660, antioxidant RD, and paraffin oil 2280 are added sequentially in a mass ratio of 100.0:0.5:4.0:1.5:2.0:35.0:40.0:1.0:15.0 for mixing. During mixing, the temperature of the closed rubber mixing mill is 70℃, the speed is 60 rpm, and after mixing for 8 minutes, the top bolt is opened to discharge the rubber and obtain the mixed rubber. The mixed rubber is then added to... The ethylene-propylene-acrylate polymer sample (compression cold resistance coefficient and volume change rate: cylinder with a diameter of 10 mm ± 0.2 mm and a height of 10 mm ± 0.2 mm; temperature resistance grade and aging coefficient: sample size of 150 mm ± 0.5 mm × 150 mm ± 0.5 mm) was vulcanized in a hot oil press at a temperature of 160℃ and a pressure of 10 MPa for 15 min. The test results are shown in Table 1.

[0077] Example 5

[0078] This embodiment provides a method for preparing an ethylene-propylene-acrylate polymer, the components of which, by weight, include: 45 parts of low-density polyethylene (LDPE, weight average molecular weight: 4.98 × 10⁻⁶). 430 parts polypropylene WAX ​​wax (weight average molecular weight: 4652 g / cm³), 25 parts hydroxypropyl methacrylate (HPMA), 0.15 parts benzoyl peroxide (BPO), and 1 part p-tert-butylcatechol.

[0079] This embodiment also provides a preparation step for an ethylene-propylene-acrylate polymer, the preparation step including:

[0080] (1) In a reaction screw extruder, polyethylene oligomer, polypropylene oligomer and acrylic functional monomer are mixed. The extruder mixing temperature is 150℃, the mixing speed is 50 rpm, the mixing time is 1 minute, and the mixture is extruded at an extrusion pressure of 12 MPa to obtain the first mixture.

[0081] (2) In a reaction screw extruder, an initiator is added to the first mixture for copolymerization. The reaction temperature of the reaction screw extruder is 140°C, the reaction speed is 40 rpm, the reaction time is 3 minutes, and the extrusion is carried out at an extrusion pressure of 12 MPa to obtain the second mixture.

[0082] (3) In a reaction screw extruder, the terminator is added to the second mixture to terminate the reaction. The termination temperature of the reaction screw extruder is 145°C, the termination speed is 50 rpm, the reaction time is 2 minutes, and the extrusion is carried out at an extrusion pressure of 12 MPa to obtain an ethylene-propylene-acrylate polymer.

[0083] (4) In a closed rubber mixing mill, ethylene-propylene-acrylate polymer, stearic acid, zinc oxide, vulcanization accelerator HVA2, vulcanizing agent bis 2-5, carbon black N330, carbon black N660, antioxidant RD, and paraffin oil 2280 are added sequentially in a mass ratio of 100.0:0.5:4.0:1.5:2.0:35.0:40.0:1.0:15.0 for mixing. During mixing, the temperature of the closed rubber mixing mill is 70℃, the speed is 60 rpm, and after mixing for 8 minutes, the top bolt is opened to discharge the rubber and obtain the mixed rubber. The mixed rubber is then added to... The ethylene-propylene-acrylate polymer sample (compression cold resistance coefficient and volume change rate: cylinder with a diameter of 10 mm ± 0.2 mm and a height of 10 mm ± 0.2 mm; temperature resistance grade and aging coefficient: sample size of 150 mm ± 0.5 mm × 150 mm ± 0.5 mm) was vulcanized in a hot oil press at a temperature of 160℃ and a pressure of 10 MPa for 15 min. The test results are shown in Table 1.

[0084] Example 6

[0085] This embodiment provides a method for preparing an ethylene-propylene-acrylate polymer, the components of which, by weight, include: 40 parts polyethylene wax (weight average molecular weight: 4625 g / cm³), 25 parts polypropylene WAX ​​wax (weight average molecular weight: 8034 g / cm³), 15 parts polyethylene glycol monomethacrylate (HEMA-5), 20 parts phenyl glycidyl ether acrylate (PGEA), 0.1 parts dicumyl peroxide (DCP), 0.5 parts hydroquinone, and 0.5 parts p-tert-butylcatechol.

[0086] This embodiment also provides a preparation step for an ethylene-propylene-acrylate polymer, the preparation step including:

[0087] (1) In a reactive screw extruder, polyethylene oligomer, polypropylene oligomer and acrylic functional monomer are mixed. The extruder mixing temperature is 145℃, the mixing speed is 60 rpm, the mixing time is 1 minute, and the mixture is extruded at an extrusion pressure of 18 MPa to obtain the first mixture.

[0088] (2) In a reaction screw extruder, an initiator is added to the first mixture for copolymerization. The reaction temperature of the reaction screw extruder is 155°C, the reaction speed is 10 rpm, the reaction time is 5 minutes, and the extrusion pressure is 18 MPa to obtain the second mixture.

[0089] (3) In a reaction screw extruder, the terminator is added to the second mixture to terminate the reaction. The termination temperature of the reaction screw extruder is 145°C, the termination speed is 80 rpm, the reaction time is 1 minute, and the extrusion is carried out at an extrusion pressure of 18 MPa to obtain an ethylene-propylene-acrylate polymer.

[0090] (4) In a closed rubber mixing mill, ethylene-propylene-acrylate polymer, stearic acid, zinc oxide, vulcanization accelerator HVA2, vulcanizing agent bis 2-5, carbon black N330, carbon black N660, antioxidant RD, and paraffin oil 2280 are added sequentially in a mass ratio of 100.0:0.5:4.0:1.5:2.0:35.0:40.0:1.0:15.0 for mixing. During mixing, the temperature of the closed rubber mixing mill is 70℃, the speed is 60 rpm, and after mixing for 8 minutes, the top bolt is opened to discharge the rubber and obtain the mixed rubber. The mixed rubber is then added to... The ethylene-propylene-acrylate polymer sample (compression cold resistance coefficient and volume change rate: cylinder with a diameter of 10 mm ± 0.2 mm and a height of 10 mm ± 0.2 mm; temperature resistance grade and aging coefficient: sample size of 150 mm ± 0.5 mm × 150 mm ± 0.5 mm) was vulcanized in a hot oil press at a temperature of 160℃ and a pressure of 10 MPa for 15 min. The test results are shown in Table 1.

[0091] Example 7

[0092] This embodiment provides a method for preparing an ethylene-propylene-acrylate polymer, the components of which, by weight, include: 30 parts of low-density polyethylene (LDPE, weight average molecular weight: 9.27 × 10⁻⁶). 4 10 parts polyethylene wax (weight average molecular weight: 4321 g / cm³), 15 parts polypropylene WAX ​​wax (weight average molecular weight: 4637 g / cm³), 20 parts phenyl glycidyl ether acrylate (PGEA), 25 parts 2-hydroxy-3-phenoxypropyl acrylate, 0.05 parts benzoyl peroxide (BPO), 0.05 parts tert-butyl peroxide, 0.05 parts tert-butyl peroxide-2-ethylhexanoate (TBPO), and 0.5 parts pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0093] This embodiment also provides a preparation step for an ethylene-propylene-acrylate polymer, the preparation step including:

[0094] (1) In a reactive screw extruder, polyethylene oligomer, polypropylene oligomer and acrylic functional monomer are mixed. The extruder mixing temperature is 170°C, the mixing speed is 60 rpm, the mixing time is 1 minute, and the mixture is extruded at an extrusion pressure of 18 MPa to obtain the first mixture.

[0095] (2) In a reaction screw extruder, an initiator is added to the first mixture for copolymerization. The reaction temperature of the reaction screw extruder is 110°C, the reaction speed is 10 rpm, the reaction time is 5 minutes, and the extrusion is carried out at an extrusion pressure of 18 MPa to obtain the second mixture.

[0096] (3) In a reaction screw extruder, the terminator is added to the second mixture to terminate the reaction. The termination temperature of the reaction screw extruder is 145°C, the termination speed is 80 rpm, the reaction time is 1 minute, and the extrusion is carried out at an extrusion pressure of 18 MPa to obtain an ethylene-propylene-acrylate polymer.

[0097] (4) In a closed rubber mixing mill, ethylene-propylene-acrylate polymer, stearic acid, zinc oxide, vulcanization accelerator HVA2, vulcanizing agent bis 2-5, carbon black N330, carbon black N660, antioxidant RD, and paraffin oil 2280 are added sequentially in a mass ratio of 100.0:0.5:4.0:1.5:2.0:35.0:40.0:1.0:15.0 for mixing. During mixing, the temperature of the closed rubber mixing mill is 70℃, the speed is 60 rpm, and after mixing for 8 minutes, the top bolt is opened to discharge the rubber and obtain the mixed rubber. The mixed rubber is then added to... The ethylene-propylene-acrylate polymer sample (compression cold resistance coefficient and volume change rate: cylinder with a diameter of 10 mm ± 0.2 mm and a height of 10 mm ± 0.2 mm; temperature resistance grade and aging coefficient: sample size of 150 mm ± 0.5 mm × 150 mm ± 0.5 mm) was vulcanized in a hot oil press at a temperature of 160℃ and a pressure of 10 MPa for 15 min. The test results are shown in Table 1.

[0098] Comparative Example 1

[0099] This embodiment provides a method for preparing an ethylene-propylene-acrylate polymer, the components of which, by weight, include: 40 parts polyethylene wax (weight average molecular weight: 2819 g / cm³), 30 parts polypropylene WAX ​​wax (weight average molecular weight: 5372 g / cm³), 30 parts hydroxyethyl methacrylate (HEMA), 0.1 parts benzoyl tert-butyl peroxide, and 0.8 parts pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0100] This embodiment also provides a preparation step for an ethylene-propylene-acrylate polymer, the preparation step including:

[0101] (1) In a reactive screw extruder, polyethylene oligomer, polypropylene oligomer, acrylic functional monomer and initiator are mixed. The extruder mixing temperature is 150℃, the mixing speed is 40 rpm, the mixing time is 5 minutes, and the mixture is extruded at an extrusion pressure of 12 MPa to obtain the first mixture.

[0102] (2) In a reaction screw extruder, the terminator is added to the first mixture to terminate the reaction. The termination temperature of the reaction screw extruder is 150°C, the termination speed is 40 rpm, the reaction time is 1.5 minutes, and the extrusion is carried out at an extrusion pressure of 12 MPa to obtain an ethylene-propylene-acrylate polymer.

[0103] (3) In a closed rubber mixing mill, ethylene-propylene-acrylate polymer, stearic acid, zinc oxide, vulcanization accelerator HVA2, vulcanizing agent bis 2-5, carbon black N330, carbon black N660, antioxidant RD, and paraffin oil 2280 are added sequentially in a mass ratio of 100.0:0.5:4.0:1.5:2.0:35.0:40.0:1.0:15.0 for mixing. During mixing, the temperature of the closed rubber mixing mill is 70℃, the speed is 60 rpm, and after mixing for 8 minutes, the top bolt is opened to discharge the rubber and obtain the mixed rubber. The mixed rubber is then added to... The ethylene-propylene-acrylate polymer sample (compression cold resistance coefficient and volume change rate: cylinder with a diameter of 10 mm ± 0.2 mm and a height of 10 mm ± 0.2 mm; temperature resistance grade and aging coefficient: sample size of 150 mm ± 0.5 mm × 150 mm ± 0.5 mm) was vulcanized in a hot oil press at a temperature of 160℃ and a pressure of 10 MPa for 15 min. The test results are shown in Table 1.

[0104] Comparative Example 2

[0105] This embodiment provides a method for preparing an ethylene-propylene-acrylate polymer, the components of which, by weight, include: 40 parts polyethylene wax (weight average molecular weight: 2819 g / cm³), 30 parts polypropylene WAX ​​wax (weight average molecular weight: 5372 g / cm³), 30 parts hydroxyethyl methacrylate (HEMA), 0.1 parts benzoyl tert-butyl peroxide, and 0.8 parts pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0106] This embodiment also provides a preparation step for an ethylene-propylene-acrylate polymer, the preparation step including:

[0107] (1) In a reactive screw extruder, polyethylene oligomer, polypropylene oligomer, acrylic functional monomer, initiator and terminator are mixed. The mixing temperature of the extruder is 150°C, the mixing speed is 40 rpm, the mixing time is 6.5 minutes, and the extrusion is carried out at an extrusion pressure of 12 MPa to obtain ethylene-propylene-acrylate polymer.

[0108] (2) In a closed rubber mixing mill, ethylene-propylene-acrylate polymer, stearic acid, zinc oxide, vulcanization accelerator HVA2, vulcanizing agent bis 2-5, carbon black N330, carbon black N660, antioxidant RD, and paraffin oil 2280 are added sequentially in a mass ratio of 100.0:0.5:4.0:1.5:2.0:35.0:40.0:1.0:15.0 for mixing. During mixing, the temperature of the closed rubber mixing mill is 70℃, the speed is 60 rpm, and after mixing for 8 minutes, the top bolt is opened to discharge the rubber and obtain the mixed rubber. The mixed rubber is then added to... The ethylene-propylene-acrylate polymer sample (compression cold resistance coefficient and volume change rate: cylinder with a diameter of 10 mm ± 0.2 mm and a height of 10 mm ± 0.2 mm; temperature resistance grade and aging coefficient: sample size of 150 mm ± 0.5 mm × 150 mm ± 0.5 mm) was vulcanized in a hot oil press at a temperature of 160℃ and a pressure of 10 MPa for 15 min. The test results are shown in Table 1.

[0109] Comparative Example 3

[0110] In a closed rubber mixing mill, ethylene-acrylate polymer (AEM, DuPont product, brand name: Vamac-G), stearic acid, zinc oxide, vulcanization accelerator HVA2, vulcanizing agent bis 2-5, carbon black N330, carbon black N660, antioxidant RD, and paraffin oil 2280 were added sequentially in a mass ratio of 100.0:0.5:4.0:1.5:2.0:35.0:40.0:1.0:15.0 and mixed. During mixing, the temperature of the closed rubber mixing mill was 70℃, the speed was 60 rpm, and after mixing for 14.5 minutes, the top bolt was opened to discharge the rubber. The compound was then vulcanized in a heated hydraulic molding machine at a temperature of 160℃, a pressure of 10MPa, and a vulcanization time of 15min. The ethylene-propylene-acrylate polymer samples (compression cold resistance coefficient and volume change rate: cylinders with a diameter of 10mm±0.2mm and a height of 10mm±0.2mm; temperature resistance grade and aging coefficient: sample size 150mm±0.5mm×150mm±0.5mm) were tested for -40℃ compression cold resistance coefficient, temperature resistance grade, IRM903 oil volume change rate, and aging coefficient. The test results are shown in Table 1.

[0111] The performance of the ethylene-propylene-acrylate polymer samples provided in Examples 1-7 and Comparative Examples 1-3 was tested using the following methods:

[0112] (1) The cold resistance coefficient of compression was tested according to the industry standard "HG / T 3866-2008 Determination of the cold resistance coefficient of vulcanized rubber" at a test temperature of -40℃;

[0113] (2) The temperature resistance rating shall be determined in accordance with "GB / T 20028-2005 Application of Arrhenius diagram to estimate the storage life and maximum service temperature of polymer materials", with compression set percentage (25% compression) as the test value and ≤30% as the test index.

[0114] (3) The oil resistance test shall be conducted in accordance with the “GB / T 1690-2010 Test method for liquid resistance of vulcanized rubber or thermoplastic rubber”, with test conditions of 70℃×96h and oil type: conforming to ASTM standard IRM903 type oil;

[0115] The volume change rate is calculated according to the following formula: Volume change rate = [(Volume of sample after oil resistance test - Volume of sample before oil resistance test) × 100%] ÷ Volume of sample before oil resistance test;

[0116] (4) Aging coefficient: Tested according to "GB / T 3512-201 Accelerated aging and heat resistance test of vulcanized rubber or thermoplastic rubber in hot air", and determined based on the change in the product of tensile strength and elongation at break of the sample. Aging coefficient = [tensile strength after aging (MPa) × elongation at break (%)] ÷ [tensile strength before aging (MPa) × elongation at break before aging (%)], test conditions: 200℃ × 240 hours;

[0117] Table 1 Test Results

[0118]

[0119] As can be seen from Examples 1-7, although the compression cold resistance coefficient, temperature resistance grade, volume change rate and aging coefficient of the material are slightly different depending on the preparation method of ethylene-propylene-acrylate polymer, the type and amount of additives added, the properties of the material provided in the examples are superior to those of the products of the prior art and have the value of promotion and application.

[0120] Analysis of Examples 3, 1, 2, and 3 shows that the performance of the ethylene-propylene-acrylate polymers provided in these examples is superior to that of Comparative Example 1 (which reduced step (2)) and Comparative Example 2 (which reduced both steps (1) and (2)). Comparative Example 3 is a prior art product, demonstrating that the present invention improves the product's low-temperature resistance, high-temperature resistance, oil resistance, and aging resistance.

[0121] Based on the above data analysis, the ethylene-propylene-acrylate polymer preparation method provided in the examples, compared with the prior art, can improve the low-temperature resistance, high-temperature resistance, oil resistance, and aging resistance of the product, and solve the problems of poor high and low temperature performance, poor oil resistance, and poor aging resistance of the materials in the prior art.

[0122] The applicant declares that this invention illustrates a method for preparing an ethylene-propylene-acrylate polymer through the above embodiments, but the invention is not limited to the above embodiments, that is, it does not mean that the invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials for the product of this invention, additions of auxiliary components, and selection of specific methods, all fall within the protection and disclosure scope of this invention.

Claims

1. A method for preparing an ethylene-propylene-acrylate polymer, characterized in that, The raw materials for preparing the ethylene-propylene-acrylate polymer include, by weight: 25-55 (preferably 28-50) parts of polyethylene oligomer, 15-45 (preferably 18-40) parts of polypropylene oligomer, 15-55 (preferably 17-53) parts of acrylic functional monomer, 0.03-0.2 parts of initiator and 0.3-1.5 parts of terminator; Under the action of an initiator, the acrylic functional monomer undergoes a polymerization reaction with ethylene oligomers and propylene oligomers to prepare an ethylene-propylene-acrylate polymer online in a reactive screw extruder.

2. The preparation method according to claim 1, characterized in that, The specific process is as follows: (1) In a reactive screw extruder, polyethylene oligomer, polypropylene oligomer and acrylic functional monomer are mixed to obtain a first mixture; (2) In a reactive screw extruder, an initiator is added to the first mixture to copolymerize and obtain a second mixture; (3) In a reactive screw extruder, a terminator is added to the second mixture to terminate the reaction and obtain an ethylene-propylene-acrylate polymer, which is then extruded.

3. The preparation method according to claim 1 or 2, characterized in that, Preferably, the polyethylene oligomer is a low molecular weight homopolymer of ethylene obtained by solution polymerization, including any one or a combination of two or more of linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), and polyethylene wax; the weight-average molecular weight distribution range for LLDPE is 15 × 10⁻⁶. 4 -20×10 4 g / cm³, LDPE: 2×10 4 -11×10 4 g / cm³, polyethylene wax 3000-4000 g / cm³, preferred LLDPE: 16×10 4 -19×10 4 g / cm³, LDPE: 3.2 × 10⁻⁶ 4 -3.8×10 4 g / cm³, polyethylene wax 3500-3800 g / cm³; Preferably, the polypropylene oligomer, also known as WAX wax, is produced by thermal cracking of high molecular weight polypropylene (weight-average molecular weight distribution range 4×10⁻⁶). 3 -15×10 4 g / cm³, preferably 10×10 4 -12×10 4 It is obtained by cracking (g / cm³), and is a crystalline waxy or soft waxy solid with a weight-average molecular weight distribution range of 5000-8000 g / cm³, preferably 6000-7000 g / cm³. Preferably, the acrylic functional monomer comprises any one or a combination of two or more of methyl 2-(hydroxymethyl)acrylate, hydroxyethyl acrylate (HEA), hydroxyethyl methacrylate (HEMA), hydroxypropyl acrylate (HPA), hydroxypropyl methacrylate (HPMA), polyethylene glycol monomethacrylate (HEMA-5), phenyl glycidyl ether acrylate (PGEA), and 2-hydroxy-3-phenoxypropyl acrylate. Preferably, the initiator is a peroxide initiator, including any one or a combination of two or more of benzoyl peroxide (BPO), dicumyl peroxide (DCP), tert-butyl peroxide and tert-butyl peroxide-2-ethylhexanoate (TBPO); Preferably, the terminator is a phenolic terminator, including any one or a combination of two or more of hydroquinone, p-tert-butylcatechol, and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

4. The preparation method according to claim 2, characterized in that, The preparation of the ethylene-propylene-acrylate polymer in step (1) includes mixing using a reactive screw extruder; Preferably, the mixing temperature of the reactive screw extruder is 125–190°C (preferably 130–180°C); Preferably, the mixing speed of the reactive screw extruder is 15-70 rpm (preferably 20-60 rpm); Preferably, the mixing time of the reactive screw extruder is 0.5 to 4.5 minutes.

5. The preparation method according to claim 2, characterized in that, The preparation of the ethylene-propylene-acrylate polymer in step (2) includes a screw extruder polymerization reaction; Preferably, the reaction temperature of the screw extruder is 95–170°C (preferably 120–160°C); Preferably, the reaction speed of the screw extruder is 5-60 rpm (preferably 20-50 rpm); Preferably, the reaction time of the screw extruder is 1 to 6 minutes.

6. The preparation method according to claim 2, characterized in that, The preparation of the ethylene-propylene-acrylate polymer in step (3) includes the termination of the polymerization reaction in a reactive screw extruder; Preferably, the termination temperature of the reaction screw extruder is 120–160°C (preferably 130–150°C); Preferably, the rotational speed of the reaction screw extruder during the termination process is 35-90 rpm (preferably 40-80 rpm); Preferably, the duration of the termination process of the reactive screw extruder is 0.5 to 3 minutes.

7. The preparation method according to claim 2, characterized in that, Extrusion pressure 8-25MPa (preferably 10-20MPa).

8. An ethylene-propylene-acrylate polymer prepared by any one of claims 1-7.

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