A modified ethylene propylene rubber and preparation method thereof

Abstract

The present invention provides a method for preparing modified ethylene-propylene rubber, comprising the following steps: A) polymerizing ethylene, propylene, and a third monomer in the presence of a catalyst system to obtain a reaction product; and B) reacting the reaction product, an alkyl aluminum compound, and an ester polar monomer to obtain the modified ethylene-propylene rubber. The present invention utilizes a staged addition method, namely, first polymerizing ethylene, propylene, and the third monomer to prepare EPDM, followed by in-situ addition of an ester monomer to prepare the functionalized EPDM. Compared to free radical monomer grafting reactions, the present invention offers controllable reactions, allowing precise control of the reaction site. Specifically, the EPDM double bond reacts with the polar monomer, while the ethylene and propylene structural units in the EPDM molecular chain do not participate in the reaction. Furthermore, by adding an ether compound during the reaction, the present invention eliminates the formation of gelled products. The present invention offers high reaction efficiency and minimal side reactions.

Description

Technical Field

[0001] The invention belongs to the technical field of rubber, and particularly relates to a modified ethylene propylene rubber and a preparation method thereof. Background Art

[0002] Ethylene-propylene-diene rubber (EPDM) is a synthetic rubber copolymerized from ethylene, propylene, and a small amount of diene. Due to its saturated backbone structure, EPDM exhibits excellent heat, weather, and aging resistance, making it widely used in the automotive industry, building materials, wire and cable, and sealing components. However, the EPDM molecular chain lacks polar groups, resulting in poor self-adhesion and inter-adhesion properties, making it incompatible with polar materials, thus limiting its application.

[0003] Currently, monomer grafting, epoxidation, halogenation, and sulfonation are commonly used to modify EPDM to improve its properties. Among these methods, grafting is considered an effective method. Some studies have used acrylic monomers to modify EPDM through free radical grafting (Synthetic Rubber Industry. 1995(02); Journal of Macromolecular Science, Part B, 48(2), 254–268.); However, this type of reaction has problems such as uncontrollable reaction sites and serious side reactions (such as polymer cross-linking and monomer self-polymerization).

[0004] In addition, direct copolymerization of ester polar monomers with olefin monomers such as ethylene and propylene to prepare functionalized EPDM is another ideal approach; however, polar monomers will affect the activity of the catalyst, making direct copolymerization to prepare polar EPDM difficult to apply in practice.

[0005] Therefore, providing a method for preparing functionalized EPDM with mild reaction conditions and high reaction selectivity has become an urgent problem to be solved. Summary of the Invention

[0006] In view of this, the technical problem to be solved by the present invention is to provide a modified EPDM rubber and a preparation method thereof. The preparation method provided by the present invention has mild reaction conditions and high reaction selectivity, and the prepared modified EPDM rubber does not generate gelled products.

[0007] The present invention provides a method for preparing modified ethylene propylene rubber, comprising the following steps:

[0008] A) in the presence of a catalyst system, ethylene, propylene and a third monomer undergo a polymerization reaction to obtain a reaction product;

[0009] B) reacting the reaction product, an alkyl aluminum compound, an ester polar monomer and an ether compound to obtain a modified ethylene propylene rubber.

[0010] Preferably, the ether compound is selected from one or more of tetrahydrofuran, isoamyl ether, isopropyl ether, diphenyl ether, 9,9-bis(methoxymethyl)fluorene), 1,1-bis(methoxymethyl)-1,3-cyclopentadiene, and 9,9-bis(methoxymethyl)-9,10-dihydroanthracene;

[0011] The molar ratio of the ether compound to the alkyl aluminum compound is 1:(50-500).

[0012] Preferably, the third monomer is selected from one or more of ethylidene norbornene, dicyclopentadiene and 1,4-hexadiene;

[0013] The mass fraction of the third monomer after the polymerization reaction in the modified EPDM rubber is 0.5-12 wt%.

[0014] Preferably, in step A), the catalytic system comprises a vanadium-based catalyst, an alkyl aluminum compound and an organic chloride;

[0015] Preferably, the vanadium-based catalyst is selected from one of a vanadium compound and a vanadium complex;

[0016] Preferably, the alkyl aluminum compound is selected from one or more of Al2(C2H5)3Cl3, AlCl3, Al(C2H5)Cl2, Al(C2H5)2Cl and Al(C2H5)3;

[0017] Preferably, the organic chloride is selected from one or more of ethyl trichloroacetate, methyl chloride, dichloromethane, and chloroform;

[0018] Preferably, the molar ratio of the vanadium catalyst to the alkyl aluminum compound is 1:(10-100); the molar ratio of the vanadium catalyst to the organic chloride is 1:(0.5-20).

[0019] Preferably, the ester polar monomer is selected from compounds having a structure shown in Formula I or Formula II;

[0020]

[0021] R1 and R2 are independently selected from C1 to C 25 Alkyl, C1~C 25 an alkoxy group, an aryl group or a hydrogen atom;

[0022] Preferably, the ester polar monomer is selected from one or more of methyl acrylate, ethyl acrylate, methyl propiolate, ethyl propiolate and pentafluorophenol propiolate;

[0023] The molar ratio of the third monomer to the ester polar monomer in step B) is 1:(0.01-5).

[0024] Preferably, in step B), the alkyl aluminum compound is selected from one or more of Al2(C2H5)3Cl3, AlCl3, Al(C2H5)Cl2, Al(C2H5)2Cl and Al(C2H5)3;

[0025] The molar ratio of the third monomer to the alkyl aluminum compound in step B) is 1:(0.01-3).

[0026] Preferably, in step A), the polymerization reaction is carried out at a temperature of 0 to 70° C., for a time of 0.5 to 2.5 h, and at a pressure of 0.1 to 0.8 MPa.

[0027] Preferably, in step B), the reaction temperature is 0 to 150° C., and the reaction time is 0.1 to 6 hours.

[0028] Preferably, step A) and step B) are reacted in the presence of a solvent, and the solvent is selected from one or more of toluene, xylene, cyclohexane, cyclopentane, n-hexane, and n-heptane.

[0029] The present invention also provides a modified ethylene propylene rubber prepared by the above preparation method.

[0030] Compared to the prior art, the present invention provides a method for preparing modified EPDM, comprising the following steps: A) polymerizing ethylene, propylene, and a third monomer in the presence of a catalytic system to obtain a reaction product; and B) reacting the reaction product, an alkyl aluminum compound, and an ester polar monomer to obtain the modified EPDM. The present invention utilizes a staged addition method, first polymerizing ethylene, propylene, and the third monomer to prepare EPDM, followed by in-situ addition of an ester monomer to prepare the functionalized EPDM. Compared to free radical monomer grafting reactions, the present invention offers controllable reactions, allowing precise control of the reaction site. Specifically, the EPDM double bond reacts with the polar monomer, while the ethylene and propylene structural units in the EPDM molecular chain do not participate in the reaction. Furthermore, by adding an ether compound during the reaction, the present invention eliminates the formation of gelled products. The present invention offers high reaction efficiency and minimal side reactions. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is the H-NMR spectrum of unmodified EPDM rubber;

[0032] Figure 2 This is the H-NMR spectrum of the modified EPDM rubber prepared in Example 1;

[0033] Figure 3 This is the H-NMR spectrum of the modified EPDM rubber prepared in Example 2;

[0034] Figure 4 This is the H-NMR spectrum of the modified EPDM rubber prepared in Example 3;

[0035] Figure 5 This is the H-NMR spectrum of the modified EPDM rubber prepared in Example 4. DETAILED DESCRIPTION

[0036] The present invention provides a method for preparing modified ethylene propylene rubber, comprising the following steps:

[0037] A) in the presence of a catalyst system, ethylene, propylene and a third monomer undergo a polymerization reaction to obtain a reaction product;

[0038] B) reacting the reaction product, an alkyl aluminum compound, an ester polar monomer and an ether compound to obtain a modified ethylene propylene rubber.

[0039] The present invention first disperses the catalyst system in a solvent to obtain a solution containing the catalyst system. The catalyst system includes a vanadium-based catalyst, an alkyl aluminum compound, and an organic chloride.

[0040] The vanadium-based catalyst is selected from one of a vanadium compound and a vanadium complex. Preferably, the vanadium-based catalyst is selected from one or more of VOCl3, V(acac)3, and VO(P2O4)2.

[0041] The alkyl aluminum compound is selected from one or more of Al2(C2H5)3Cl3, AlCl3, Al(C2H5)Cl2, Al(C2H5)2Cl and Al(C2H5)3, preferably Al2(C2H5)3Cl3, Al(C2H5)2Cl;

[0042] Preferably, the organic chloride is selected from one or more of ethyl trichloroacetate, methyl chloride, dichloromethane, and chloroform, preferably ethyl trichloroacetate;

[0043] Preferably, the molar ratio of the vanadium catalyst to the alkyl aluminum compound is 1:(10-100), which can be 1:10, 1:20, 1:30, 1:40, 1:50, 1:60, 1:70, 1:80, 1:90, 1:100, or any value between 1:(10-100);

[0044] The molar ratio of the vanadium catalyst to the organic chloride is 1:(0.5-20), and can be 1:0.5, 1:1, 1:2, 1:4, 1:5, 1:6, 1:8, 1:10, 1:12, 1:14, 1:15, 1:16, 1:18, 1:20, or any value between 1:(0.5-20).

[0045] The solvent of the dispersed catalytic system is selected from one or more of toluene, xylene, cyclohexane, cyclopentane, n-hexane, and n-heptane, preferably toluene.

[0046] Then, the solution containing the catalytic system is placed in a reaction kettle under protective atmosphere conditions, wherein the protective atmosphere is preferably a nitrogen atmosphere.

[0047] Next, ethylene / propylene mixed gas and the third monomer are added into the reactor.

[0048] Wherein, the molar ratio of ethylene to propylene in the ethylene / propylene mixed gas is 1:2.

[0049] The third monomer is selected from one or more of ethylidene norbornene, dicyclopentadiene and 1,4-hexadiene, preferably ethylidene norbornene;

[0050] The content of the third monomer is 0.5-12wt%, and can be 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, or any value between 0.5 and 12wt%.

[0051] After the addition of the raw materials is completed, a polymerization reaction is carried out to obtain a reaction product. The polymerization reaction temperature is 0 to 70° C., which can be 0, 5, 10, 20, 30, 40, 50, 60, 70, or any value between 0 and 70° C., the time is 0.5 to 2.5 hours, which can be 0.5, 1, 1.5, 2, 2.5, or any value between 0.5 and 2.5 hours, and the pressure is 0.1 to 0.8 MPa, which can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or any value between 0.1 and 0.8 MPa.

[0052] After the reaction is completed, an alkyl aluminum compound, an ester polar monomer and an ether compound are added to the reaction product.

[0053] Wherein, the ester polar monomer is selected from a compound having a structure shown in Formula I or Formula II;

[0054]

[0055] R1 and R2 are independently selected from C1 to C 25 Alkyl, C1~C 25 an alkoxy group, an aryl group or a hydrogen atom;

[0056] Preferably, the ester polar monomer is selected from one or more of methyl acrylate, ethyl acrylate, methyl propiolate, ethyl propiolate, and pentafluorophenol propiolate, and more preferably one or more of ethyl propioate, methyl propioate, and ethyl acrylate. The molar ratio of the third monomer to the ester polar monomer in step B) is 1:(0.01-5), and can be 1:0.01, 1:0.05, 1:0.1, 1:0.5, 1:1, 1:2, 1:3, 1:4, 1:5, or any value in between.

[0057] The alkyl aluminum compound is selected from one or more of Al2(C2H5)3Cl3, Al2(C2H5)3Cl3, AlCl3, Al(C2H5)Cl2, Al(C2H5)2Cl and Al(C2H5)3, preferably ethylaluminum dichloride or triethylaluminum trichloride;

[0058] The molar ratio of the third monomer to the alkyl aluminum compound in step B) is 1:(0.01-3), and can be 1:0.01, 1:0.05, 1:0.1, 1:0.5, 1:1, 1:2, 1:3 or any value in between 1:(0.01-3).

[0059] The ether compound is selected from one or more of tetrahydrofuran, isoamyl ether, isopropyl ether, diphenyl ether, 9,9-bis(methoxymethyl)fluorene, 1,1-bis(methoxymethyl)-1,3-cyclopentadiene, and 9,9-bis(methoxymethyl)-9,10-dihydroanthracene. The ether compound added in the present invention is an electron donor, and the addition of the electron donor can effectively inhibit gel formation during the reaction.

[0060] The molar ratio of the ether compound to the alkyl aluminum compound is 1:(50-500), and can be 1:50, 1:100, 1:150, 1:200, 1:250, 1:300, 1:350, 1:400, 1:450, 1:500, or any value between 1:(50-500).

[0061] After the addition of the raw materials is completed, a reaction is carried out to obtain a modified ethylene propylene rubber. The reaction temperature is 0 to 150°C, and can be 0, 10, 20, 25, 30, 40, 50, 60, 70, 80, 90, 100, or any value between 0 and 150°C, preferably room temperature. In the present invention, the room temperature is defined as 25±5°C, and the reaction time is 0.1 to 24 hours, and can be 0.1, 0.5, 1, 3, 5, 6, 7, 9, 10, 12, 15, 20, 24, or 0.1 to 24 hours. Further, the reaction is carried out under normal pressure.

[0062] After the reaction is completed, the product is vacuum dried to a constant weight to obtain modified ethylene propylene rubber.

[0063] The present invention also provides a modified ethylene propylene rubber prepared by the above preparation method.

[0064] In some specific embodiments of the present invention, when the ester polar monomer is ethyl acrylate, the modified ethylene propylene rubber is selected from at least one compound having a structure represented by Formula III to Formula V:

[0065]

[0066] In Formula III to Formula V, the molecular chain represents a copolymer structure of ethylene and propylene. In the present invention, it may be a random copolymer structure, and the value of z is 1-5.

[0067] The present invention utilizes a staged addition method, first polymerizing ethylene, propylene, and a third monomer to produce EPDM, followed by the in-situ addition of an ester monomer to produce the functionalized EPDM. Furthermore, by adding an ether compound during the reaction, the present invention eliminates the formation of gelled products. This method offers high reaction efficiency and few side reactions. Compared to free radical monomer grafting reactions, the present invention is controllable, allowing precise control of the reaction site. Specifically, the EPDM double bond reacts with the polar monomer, while the ethylene and propylene structural units in the EPDM molecular chain do not participate in the reaction. This method offers high reaction efficiency and few side reactions.

[0068] In order to further understand the present invention, the modified ethylene propylene rubber and the preparation method thereof provided by the present invention are described below in conjunction with examples. The protection scope of the present invention is not limited by the following examples.

[0069] Example 1

[0070] A method for preparing modified EPDM rubber comprises the following steps:

[0071] (1) A 60 mL toluene solution containing 0.05 mmol of vanadium catalyst (VOCl3), 0.30 mmol of ethyl trichloroacetate (ETCA), and 0.5 mmol of triethylaluminum trichloride (Al2(C2H5)3Cl3, EASC) was introduced into a 0.1 L reactor under a nitrogen atmosphere. Next, an ethylene / propylene mixture (ethylene:propylene molar ratio of 1:2) and 1.66 mmol of the third monomer, ethylidene norbornene (ENB), were added to the reactor (at a pressure of 0.4 MPa) and reacted at 20°C for 30 min.

[0072] (2) 1.2 mmol of ethylaluminum dichloride, 1.0 mmol of ethyl propiolate, 0.006 mmol of 1,1-bis(methoxymethyl)-1,3-cyclopentadiene) and 0.006 mmol of tetrahydrofuran were added to the above system, and the reaction was continued at 25°C for 3 hours. Then, 5 mL of ethanol solution containing 5% by mass of hydrochloric acid was added to terminate the reaction, and the product was washed with ethanol to remove the ungrafted ethyl propiolate. The final product was vacuum dried at 40°C to a constant weight to obtain 4 g of modified EPDM rubber, and the product was gel-free. (The molar ratio of grafted ethyl propiolate to the unreacted third monomer double bond in the modified EPDM is 0.44, and the characteristic peak of grafted ethyl propiolate is located at Figure 2 (Point b in the middle).

[0073] Example 2

[0074] A method for preparing modified EPDM rubber comprises the following steps:

[0075] (1) A 60 mL toluene solution containing 0.05 mmol of vanadium catalyst (V(acac)3), 0.50 mmol of ethyl trichloroacetate (ETCA), and 1.5 mmol of diethylaluminum monochloride (Al(C2H5)2Cl, EASC) was introduced into a 0.1 L reactor under a nitrogen atmosphere. Next, an ethylene / propylene mixture (ethylene:propylene molar ratio of 1:2) and 0.83 mmol of the third monomer, ethylidene norbornene (ENB), were added to the reactor (pressure of 0.4 MPa) and reacted at 20°C for 30 min.

[0076] (2) 2.5 mmol of ethylaluminum dichloride, 0.003 mmol of 9,9-bis(methoxymethyl)fluorene), 0.003 mmol of isopropyl ether and 4.2 mmol of ethyl propiolate were added to the above system. After the reaction was carried out at 25°C for 0.5 hours, 5 mL of an ethanol solution containing 5% by mass of hydrochloric acid was added to terminate the reaction. The product was washed with ethanol to remove the ungrafted ethyl propiolate. The final product was vacuum dried at 40°C to a constant weight to obtain 3.5 g of modified EPDM rubber. The product was gel-free. (The molar ratio of grafted ethyl propiolate to the unreacted third monomer double bond in the modified EPDM was 7.88, see Figure 3 ).

[0077] Example 3

[0078] A method for preparing modified EPDM rubber comprises the following steps:

[0079] (1) 60 mL containing 0.05 mmol of vanadium catalyst (VO(P 2042) A toluene solution of 1.0 mmol of ethyl trichloroacetate (ETCA) and 1.5 mmol of triethylaluminum trichloride (Al2(C2H5)3Cl3) was introduced into a 0.1 L reactor under a nitrogen atmosphere. Next, an ethylene / propylene mixture (ethylene:propylene molar ratio of 1:2) and 5 mmol of the third monomer, ethylidene norbornene (ENB), were added to the reactor (at a pressure of 0.4 MPa) and reacted at 20°C for 30 minutes.

[0080] (2) 2.3 mmol of ethylaluminum dichloride, 1.5 mmol of ethyl propiolate, 0.1 mmol of methyl propiolate and 0.005 mmol of 9,9-bis(methoxymethyl)-9,10-dihydroanthracene were added to the above system and reacted at 25°C for 2 h. Then, 5 mL of ethanol solution containing 5% by mass of hydrochloric acid was added to terminate the reaction. The product was washed with ethanol to remove ungrafted methyl propiolate and ethyl propiolate. The final product was vacuum dried at 40°C to constant weight to obtain 4.5 g of modified EPDM rubber. The product was gel-free. (The molar ratio of grafted ethyl propiolate to the unreacted third monomer double bond in the modified EPDM is 0.21, see Figure 4 ).

[0081] Example 4

[0082] A method for preparing modified EPDM rubber comprises the following steps:

[0083] (1) 60 mL containing 0.05 mmol of vanadium catalyst (VO(P 204 2) A toluene solution of 1.0 mmol of ethyl trichloroacetate (ETCA) and 1.5 mmol of triethylaluminum trichloride (Al2(C2H5)3Cl3, EASC) was introduced into a 0.1 L reactor under a nitrogen atmosphere. Next, an ethylene / propylene mixture (ethylene:propylene molar ratio of 1:2) and 5 mmol of the third monomer, ethylidene norbornene (ENB), were added to the reactor (at a pressure of 0.4 MPa) and reacted at 20°C for 30 minutes.

[0084] (2) 1.5 mmol of triethylaluminum trichloride, 1.7 mmol of ethylaluminum dichloride, 0.25 mmol of ethyl acrylate, 3 mmol of ethyl propiolate, 0.06 mmol of 9,9-bis(methoxymethyl)-9,10-dihydroanthracene and 0.005 mmol of isoamyl ether were further added to the above system. After the reaction for 1 hour, 5 mL of an ethanol solution containing 5% by mass of hydrochloric acid was added to terminate the reaction, and the product was washed with ethanol to remove the ungrafted ethyl acrylate and ethyl propiolate. The final product was vacuum dried at 40°C to a constant weight to obtain 4.5 g of modified ethylene-propylene rubber, which was gel-free. (The molar ratio of grafted ethyl acrylate and ethyl propiolate to the unreacted third monomer double bond in the modified EPDM is 0.48, see Figure 5 ).

[0085] Example 5

[0086] A method for preparing modified EPDM rubber comprises the following steps:

[0087] (1) 60 mL containing 0.05 mmol of vanadium catalyst (VO(P 204 2) A toluene solution of 1.0 mmol of ethyl trichloroacetate (ETCA) and 1.5 mmol of triethylaluminum trichloride (Al2(C2H5)3Cl3, EASC) was introduced into a 0.1 L reactor under a nitrogen atmosphere. Next, an ethylene / propylene mixture (ethylene:propylene molar ratio of 1:2) and 5 mmol of the third monomer, ethylidene norbornene (ENB), were added to the reactor (at a pressure of 0.4 MPa) and reacted at 20°C for 30 minutes.

[0088] (2) 0.05 mmol of ethylaluminum dichloride, 0.025 mmol of methyl propiolate, 0.025 mmol of ethyl propiolate, and 0.0001 mmol of 9,9-bis(methoxymethyl)fluorene were added to the above system. After 1 h of reaction, 5 mL of ethanol solution containing 5% by mass hydrochloric acid was added to terminate the reaction. The product was washed with ethanol to remove ungrafted methyl propiolate and ethyl propiolate. The final product was vacuum dried at 40°C to constant weight to obtain 4.5 g of modified ethylene-propylene rubber, which was gel-free.

[0089] Comparative Example 1

[0090] A 60 mL toluene solution containing 0.05 mmol of vanadium catalyst (VOCl₃), 0.30 mmol of ethyl trichloroacetate (ETCA), and 0.5 mmol of triethylaluminum trichloride (Al₂(C₂H₃)₃Cl₃) was introduced into a 0.1 L reactor under a nitrogen atmosphere. Next, an ethylene / propylene mixture (ethylene:propylene molar ratio of 1:2) was added, along with 1.66 mmol of a third monomer (ethylidene norbornene (ENB), 1.2 mmol of ethylaluminum dichloride, 1.0 mmol of ethyl propiolate, and 0.006 mmol of 1,1-bis(methoxymethyl)-1,3-cyclopentadiene) and 0.006 mmol of tetrahydrofuran. The mixture was reacted at 25°C for 3 hours, but no polymerization product was obtained.

[0091] Comparative Example 2

[0092] A method for preparing modified EPDM rubber comprises the following steps:

[0093] (1) 60 mL containing 0.05 mmol of vanadium catalyst (VO(P 2042) A toluene solution of 1.0 mmol of ethyl trichloroacetate (ETCA) and 1.5 mmol of triethylaluminum trichloride (Al2(C2H5)3Cl3) was introduced into a 0.1 L reactor under a nitrogen atmosphere. Next, an ethylene / propylene mixture (ethylene:propylene molar ratio of 1:2) and 5 mmol of the third monomer, ethylidene norbornene (ENB), were added to the reactor (at a pressure of 0.4 MPa) and reacted at 20°C for 30 minutes.

[0094] (2) 2.3 mmol of ethylaluminum dichloride, 1.5 mmol of ethyl propiolate, and 0.1 mmol of methyl propiolate were added to the above system. After reacting at 25°C for 2 h, 5 mL of ethanol solution containing 5% by mass hydrochloric acid was added to terminate the reaction, and the product was washed with ethanol. The final product was vacuum dried at 40°C to constant weight to obtain 4.5 g of modified ethylene-propylene rubber with a gel content of 42%.

[0095] Comparative Example 3

[0096] 60mL contains 0.05mmol vanadium catalyst (VO(P 204 2) A toluene solution of 1.0 mmol of ethyl trichloroacetate (ETCA) and 1.5 mmol of triethylaluminum trichloride (Al2(C2H5)3Cl3) was introduced into a 0.1 L nitrogen atmosphere reactor. Next, an ethylene / propylene mixture (ethylene to propylene molar ratio of 1:2) and 5 mmol of a third monomer, ethylidene norbornene (ENB), were added to the reactor (pressure of 0.4 MPa) and reacted at 20°C for 30 minutes to obtain unmodified ethylene propylene rubber. The H NMR spectrum of unmodified ethylene propylene rubber can be found at Figure 1 , where the double bond peak of the third monomer of EPDM rubber is located at a and a'.

[0097] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing modified ethylene propylene rubber, characterized in that: The following steps are involved: A) in the presence of a catalyst system, polymerizing ethylene, propylene, and a third monomer to obtain a reaction product, wherein the polymerization reaction temperature is 0-70° C., the reaction time is 0.5-2.5 hours, and the pressure is 0.1-0.8 MPa; B) reacting the reaction product, an alkyl aluminum compound, an ester polar monomer, and an ether compound to obtain a modified ethylene propylene rubber; The ether compound is selected from one or more of tetrahydrofuran, isoamyl ether, isopropyl ether, diphenyl ether, 9,9-bis(methoxymethyl)fluorene), 1,1-bis(methoxymethyl)-1,3-cyclopentadiene, and 9,9-bis(methoxymethyl)-9,10-dihydroanthracene; The molar ratio of the ether compound to the alkyl aluminum compound is 1:(50-500); The mass fraction of the third monomer after the polymerization reaction in the modified EPDM rubber is 0.5-12 wt%; The ester polar monomer is selected from one or more of methyl acrylate, ethyl acrylate, methyl propiolate, ethyl propiolate and pentafluorophenol propiolate; The molar ratio of the third monomer to the ester polar monomer in step B) is 1: (0.01-5); The reaction temperature is 0-150° C., and the reaction time is 0.1-6 h.

2. The preparation method according to claim 1, characterized in that The third monomer is selected from one or more of ethylidene norbornene, dicyclopentadiene and 1,4-hexadiene.

3. The preparation method according to claim 1, characterized in that In step A), the catalytic system includes a vanadium-based catalyst, an alkyl aluminum compound and an organic chloride; The vanadium-based catalyst is selected from one of a vanadium compound and a vanadium complex; The alkyl aluminum compound is selected from one or more of Al2(C2H5)3Cl3, AlCl3, Al(C2H5)Cl2, Al(C2H5)2Cl and Al(C2H5)3; The organic chloride is selected from one or more of ethyl trichloroacetate, methyl chloride, dichloromethane, and chloroform; The molar ratio of the vanadium catalyst to the alkyl aluminum compound is 1:(10-100); the molar ratio of the vanadium catalyst to the organic chloride is 1:(0.5-20).

4. The preparation method according to claim 1, characterized in that In step B), the alkyl aluminum compound is selected from one or more of Al2(C2H5)3Cl3, AlCl3, Al(C2H5)Cl2, Al(C2H5)2Cl and Al(C2H5)3; The molar ratio of the third monomer to the alkyl aluminum compound in step B) is 1:(0.01-3).

5. The preparation method according to claim 1, characterized in that Step A) and step B) are reacted in the presence of a solvent, and the solvent is selected from one or more of toluene, xylene, cyclohexane, cyclopentane, n-hexane, and n-heptane.

6. A modified ethylene-propylene rubber prepared by the preparation method according to any one of claims 1 to 5, characterized in that: The modified EPDM rubber is selected from at least one compound having a structure shown in Formula III to Formula V: Formula III; Formula IV; Formula V; In Formula III to Formula V, the molecular chain represents a copolymer structure of ethylene and propylene, and the value of z is 1 to 5.

Images