Special oil field hydrogenated nitrile rubber and its preparation method

Abstract

The application discloses a preparation method of hydrogenated butyl nitrile rubber for special oil fields, and the preparation method comprises the following steps: (1) preparing a macromolecular three-hetero-arm star-shaped composite functionalized grafting agent; and (2) preparing the hydrogenated butyl nitrile rubber for special oil fields; the macromolecular three-hetero-arm star-shaped composite functionalized grafting agent has the following structure: wherein R is a linear alkyl group with 1-6 carbon atoms; BR is a 1,3-butadiene homopolymer segment with a wide ethylene group distribution; B is a capped 1,3-butadiene; n, m and L are the number of repeating units, and n is a positive integer greater than or equal to 1, m is a positive integer greater than or equal to 1, and L is a positive integer greater than or equal to 1; the number average molecular weight (Mn) of the macromolecular three-hetero-arm star-shaped composite functionalized grafting agent is 7000-8000, and the molecular weight distribution (Mw / Mn) is 13.17-14.67. The preparation method of the hydrogenated butyl nitrile rubber for special oil fields has the characteristics of green environmental protection, efficient modification effect, low modifier consumption, easy availability of raw materials on the market and suitability for industrial production.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of rubber, and particularly relates to a macromolecular three-hetero-arm star-shaped composite functional grafting agent and a preparation method of a special hydrogenated nitrile rubber for oil fields. BACKGROUND

[0002] Hydrogenated nitrile rubber (abbreviated as HNBR) is prepared by selectively hydrogenating carbon-carbon double bonds in nitrile rubber. Therefore, HNBR not only retains the oil resistance, corrosion resistance and elasticity of NBR, but also exhibits superior aging resistance and high temperature resistance, and the mechanical properties such as tensile strength, elongation at break, wear resistance and hardness are improved. HNBR is widely used in petroleum exploration equipment such as pump pistons, rotary hoses, valve sealing rings and drill pipe shrouds.

[0003] Although hydrogenation of carbon-carbon double bonds endows HNBR with very excellent properties, it also brings a serious defect problem to HNBR material. The main chain of hydrogenated nitrile rubber (abbreviated as NBR) is a highly ordered polyethylene structure, which is very easy to form a crystalline structure, and also causes the increase of Tg. Therefore, the cold resistance of HNBR products is poor. Since most of China's oil drilling business is concentrated in the western and northeastern regions, the minimum temperature in these regions can reach about -50℃, and the oil drilling equipment faces the application environment under low temperature conditions, which puts forward very high requirements on the cold resistance of rubber sealing materials.

[0004] There are many patent literatures about the preparation method of low-temperature-resistant hydrogenated nitrile rubber in the prior art. For example:

[0005] CN 106349410 B discloses a special hydrogenated nitrile rubber with compression cold resistance and a preparation method thereof. The rubber main chain contains epoxy groups, and part of the epoxy groups are further connected with ester side groups. The ester side groups are generated by ring-opening reaction of C6-C24 acid anhydride and the epoxy groups. The preparation method comprises introducing epoxy groups into the rubber molecular main chain, and then introducing ester groups by reacting part of the epoxy groups with acid anhydride under the action of a catalyst to obtain a special hydrogenated nitrile rubber containing epoxy groups and ester groups. CN 105294939 B discloses a low-temperature-grade hydrogenated nitrile rubber raw rubber, which is a copolymer of butadiene, acrylonitrile and dibutyl fumarate. The number average molecular weight of the copolymer is 1.05-3.25 x 10 5 , and the weight average molecular weight is 3.02-9.32 x 10 5polydispersity coefficient is 2.0-2.7; the hydrogenation degree of the low-temperature grade hydrogenated butyl nitrile rubber raw rubber is above 90%, and the glass transition temperature is -38℃ to -42℃. CN 112592461 B discloses a modified hydrogenated butyl nitrile rubber material with the characteristics of low-temperature resistance and high damping, and a preparation method and application thereof. The modified hydrogenated butyl nitrile rubber material is prepared by using an HNBR / PNB block copolymer as raw material; the HNBR / PNB block copolymer is obtained by modifying NBR or HNBR through olefin metathesis reaction with norbornene monomer as modifier. CN 115594898 A discloses a low-temperature resistant hydrogenated butyl nitrile rubber compound and a banburying preparation method thereof, mainly blending, banburying hydrogenated butyl nitrile rubber, plasticizer and hardness regulator, finally obtaining a hydrogenated butyl nitrile rubber compound with a Shore A hardness of 67±5, a tensile strength of ≥14 MPa, an elongation at break of ≥180%, a compression set of ≤35%, and a 45℃ compression cold resistance coefficient of ≥0.16. CN 105754164 A discloses a low-temperature resistant rubber material, although the material has improved low-temperature resistance, but the addition of plasticizer dioctyl phthalate (DOP) has reduced the mechanical properties and oil resistance of the material, and DOP is not environmentally friendly and can be precipitated. Zhang Dongheng et al. disclosed that the low-temperature resistance of HNBR can be improved by blending ethylene-propylene rubber (EPDM) with HNBR, and when the addition amount of EPDM is 15%, the Tg decreases by 3℃; but further increasing the amount of EPDM, the Tg of the blended rubber does not decrease any more (Synthetic Rubber Industry, 2002, 25(1): )。

[0006] In the above prior art, although the low-temperature resistance of hydrogenated butyl nitrile rubber can be improved to some extent by adding small molecule modifiers, copolymerization and blending methods, these methods still have certain limitations, and the preparation methods have the problems of complex process, difficult actual operation, large addition amount, high cost, and unobvious modification effect. SUMMARY

[0007] In order to solve the problems existing in the prior art, a preparation method of a special hydrogenated nitrile rubber for oil fields is provided, which has a tear strength of the raw rubber of ≥78 KN / m, a compression set resistance of ≤9.0%, and a glass transition temperature Tg of <-80℃. The 2,4,6-trihydroxyphenyl allyl ether is first subjected to a hydrolysis reaction to synthesize 2,4,6-trihydroxyphenyl allyl ether, and then a macromolecular complex functional monomer is prepared from the 2,4,6-trihydroxyphenyl allyl ether and 4-hydroxy-3-alkoxy-1-propenylbenzene. Secondly, a macromolecular three-hetero-arm star-shaped complex functional grafting agent with a wide ethylene group distribution and a random gradient segment is prepared from the macromolecular complex functional monomer, p-alkylstyrene, 1,3-butadiene and styrene through temperature polymerization, variable speed polymerization and distribution coupling. The grafting agent endows the hydrogenated nitrile rubber with excellent tear strength, deformation resistance and cold resistance, realizes the balance among the mechanical properties, deformation resistance and cold resistance of the hydrogenated nitrile rubber, and is very suitable for the oil well operation requirements of the submersible screw pump stator rubber material under low temperature conditions.

[0008] Unless otherwise specified, the "parts" in the present application refer to mass parts, the "%" refers to mass percentage, and the "ratio" refers to mass ratio.

[0009] In order to achieve the above-mentioned purpose, the present application provides a preparation method of a special hydrogenated nitrile rubber for oil fields, which comprises the following steps:

[0010] (1) Preparation of a macromolecular three-hetero-arm star-shaped complex functional grafting agent:

[0011] a Preparation of 2,4,6-trihydroxyphenyl allyl ether: in a polymerization kettle, argon is introduced to replace the system, deionized water, 2,4,6-tribromophenyl allyl ether and NaOH aqueous solution are sequentially added into the polymerization kettle, stirred, mixed, heated, warmed, reacted, and finally extracted, separated, washed, and dried to obtain 2,4,6-trihydroxyphenyl allyl ether;

[0012] b Preparation of a macromolecular complex functional monomer: in a polymerization kettle, argon is introduced to replace the system, a solvent, 4-hydroxy-3-alkoxy-1-propenylbenzene, 2,4,6-trihydroxyphenyl allyl ether and a structure regulator are sequentially added into the polymerization kettle, warmed, and then an initiator 1 is added into the polymerization kettle for reaction; finally, 1,3-butadiene is added into the polymerization kettle for end-capping, and the reaction is continued until no free monomer exists; the glue solution is subjected to wet coagulation and drying to obtain the macromolecular complex functional monomer;

[0013] Preparation of c SB / (S→B) copolymer: Argon gas was introduced into the polymerization reactor to replace the system. Solvent and structure modifier were added to the polymerization reactor in sequence. The temperature was raised and initiator 1 was added. Then, 1,3-butadiene and styrene were stirred and mixed and added to the polymerization reactor. The reaction was carried out until no free monomers were present. The glue solution was wet coagulated and dried to obtain random, long gradient segment SB / (S→B) copolymer.

[0014] Preparation of d-macromolecule three-hetero-arm star-shaped composite functionalized grafting agent: In a polymerization reactor, argon gas is introduced to purge the system. Solvent 1, p-alkylstyrene, and a first structure modifier are added sequentially to the reactor. The temperature is raised, and initiator 1 is added to react and form p-alkylstyrene homopolymer segments. Then, 1,3-butadiene and a second structure modifier are added sequentially to the reactor. The temperature is raised, and the reaction is a temperature-switched polymerization. The temperature is gradually increased from 60℃ to 90℃ within 40–60 min to form BR segments with a wide vinyl distribution. Subsequently, a coupling agent is added to carry out a coupling reaction. Then, S... The B / (S→B) copolymer and solution were mixed and stirred until completely dissolved, and then added to the polymerization reactor for coupling reaction. Finally, the macromolecular composite functionalized monomer was mixed with solvent 2 and stirred until completely dissolved, and then added to the polymerization reactor for coupling reaction. Finally, 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction continued until no free monomers were present. After the reaction was completed, the coupled reaction mixture was treated with water, and the gel was wet coagulated and dried to obtain a macromolecular three-hetero-arm star-shaped composite functionalized grafting agent.

[0015] (2) Preparation of hydrogenated nitrile butadiene rubber for special oilfield applications:

[0016] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Nitrile butadiene rubber is dissolved in chlorobenzene solution to prepare a rubber solution. The rubber solution is then added to a reaction vessel, and an inert gas is introduced to remove the air from the reaction vessel. After the inert gas in the reaction vessel is removed by hydrogen, a xylene solution of Grubbs I catalyst is added under nitrogen protection. The pressure is increased, the temperature is raised, and after the reaction, the system is cooled, condensed, and vacuum dried to obtain HNBR rubber.

[0017] b. Preparation of hydrogenated nitrile butadiene rubber for special oilfields: HNBR rubber is dissolved in chlorobenzene solution to prepare a rubber solution. The rubber solution is then added to a reaction vessel, and an inert gas is introduced for purging. A macromolecular three-arm star-shaped composite functionalized grafting agent is then added to the reaction vessel. The mixture is stirred, heated, and a mixture of initiator 2 and chlorobenzene is added. After the reaction, the mixture is flocculated, washed, and dried to obtain hydrogenated nitrile butadiene rubber for special oilfields.

[0018] The macromolecular three-hetero-arm star-shaped composite functionalized grafting agent has the following structure:

[0019]

[0020] Wherein, R is a C1-C6 straight-chain alkyl group; BR is a 1,3-butadiene homopolymer segment with a broad vinyl distribution; B is a capped 1,3-butadiene; n, m, and L are the number of repeating units, where n≥1, m≥1, and L≥1 are positive integers; the number average molecular weight (Mn) of the macromolecular tri-hetero-arm star-shaped composite functionalized grafting agent is 7000-8000, and the molecular weight distribution (Mw / Mn) is 13.17-14.67.

[0021] The p-alkylstyrene described in this invention is an aryl vinyl compound selected from p-methylstyrene, p-ethylstyrene, p-propylstyrene, p-butylstyrene, p-pentylstyrene, and p-hexylstyrene, with p-methylstyrene being preferred.

[0022] The 4-hydroxy-3-alkoxy-1-propenylbenzene of this invention is an unsaturated organic compound selected from one of 4-hydroxy-3-methoxy-1-propenylbenzene, 4-hydroxy-3-ethoxy-1-propenylbenzene, 4-hydroxy-3-propoxy-1-propenylbenzene, 4-hydroxy-3-butoxy-1-propenylbenzene, 4-hydroxy-3-pentoxy-1-propenylbenzene, and 4-hydroxy-3-hexyloxy-1-propenylbenzene, preferably 4-hydroxy-3-ethoxy-1-propenylbenzene.

[0023] The initiator 1 described in this invention is a hydrocarbon-based monolithium compound, namely RLi, wherein R is a saturated aliphatic hydrocarbon group, alicyclic hydrocarbon group, aromatic group, or a complex group containing 1 to 20 carbon atoms. This hydrocarbon-based monolithium compound is selected from one of n-butyllithium, sec-butyllithium, methylbutyllithium, phenylbutyllithium, naphthenelithium, cyclohexyllithium, and dodecyllithium, preferably n-butyllithium. The amount of organolithium added is determined by the molecular weight of the designed polymer.

[0024] The initiator 2 described in this invention is an organic peroxide selected from one of diacetyl peroxide, diisobutyryl peroxide, cumene hydroperoxide, diisobutyryl peroxide (DCP), and benzoyl peroxide (BPO), preferably DCP, and its addition amount is 0.05 to 0.2 parts based on 100 parts by weight of HNBR rubber.

[0025] The coupling agent described in this invention is one of 1,3,5-trichlorobenzene and 1,3,5-tribromobenzene, preferably 1,3,5-trichlorobenzene. Its dosage depends on the amount of initiator 1. Through excess coupling agent, polymerization proceeds stepwise, ultimately forming a star polymer with a heterostructure. The molar ratio of total initiator 1 to coupling agent is 3.0 to 4.0.

[0026] The nitrile rubber of this invention is copolymerized from 1,3-butadiene and acrylonitrile via emulsion polymerization. The acrylonitrile content of the nitrile rubber is 20 wt% to 42 wt%, preferably 22 wt% to 35 wt%.

[0027] The structure modifier described in this invention is a polar organic compound that produces a solvation effect in the polymerization system, enabling it to adjust the reactivity ratio of styrene and 1,3-butadiene, thus allowing them to copolymerize randomly. This type of polar organic compound is selected from one of diethylene glycol dimethyl ether (2G), tetrahydrofuran (THF), diethyl ether, ethyl methyl ether, anisole, diphenyl ether, diethylene glycol dimethyl ether (DME), and triethylamine, preferably tetrahydrofuran (THF).

[0028] The solvent, solvent 1, solvent 2 or solution described in this invention may be selected from one of cyclohexane, carbon disulfide (CS2), nitrobenzene, petroleum ether, tetrachloroethane, toluene, and xylene, with cyclohexane being preferred.

[0029] In step (1)a of this invention, the mass ratio of deionized water, 2,4,6-tribromophenylallyl ether, and NaOH aqueous solution is 300-400:100:20-30.

[0030] In step (1)a of the present invention, the mass concentration of the NaOH aqueous solution is 10% to 20%.

[0031] In step (1)a of the present invention, the temperature is raised to 130-140°C; the reaction time is 6-8 hours.

[0032] In step (1)a of the present invention, the yield of the 2,4,6-trihydroxyphenyl allyl ether is 80% to 83%.

[0033] In step (1)b of the present invention, the mass ratio of the solvent, 4-hydroxy-3-alkoxy-1-propenylbenzene, 2,4,6-trihydroxyphenylallyl ether, structure modifier, and 1,3-butadiene is 200-300:30-40:60-70:0.3-0.5:2-5.

[0034] In step (1)b of the present invention, the temperature is raised to 70-80°C.

[0035] In step (1)b of the present invention, the reaction time after adding initiator 1 is 90-100 min.

[0036] In step (1)b of the present invention, the reaction time for capping with 1,3-butadiene is 30-40 min.

[0037] In step (1)c of the present invention, the mass ratio of the solvent, structure modifier, 1,3-butadiene and styrene is 300-400: 0.1-0.4: 100: 30-40.

[0038] In step (1)c of the present invention, the temperature is raised to 60-70°C.

[0039] In step (1)c of the present invention, the stirring and mixing time is 20-30 min; the reaction time is 70-80 min; the initial feeding rate is >8.0% mixture / min; and the decrease in feeding rate depends on the reaction time.

[0040] In step (1) d of the present invention, the mass ratio of solvent 1, p-alkylstyrene, primary structure modifier, 1,3-butadiene, secondary structure modifier, SB / (S→B) copolymer, solution, macromolecular composite functionalized monomer, and solvent 2 is 200-300:100:0.3-0.6:50-60:0.05-0.1:20-30:100-200:5-10:50-100.

[0041] In step (1) d of the present invention, before adding initiator 1, the temperature is raised to 50-60°C; after adding initiator 1, the reaction time is 80-90 min.

[0042] In step (1) d of this invention, the coupling agent is added and the coupling reaction takes 60 to 70 minutes.

[0043] In step (1) d of this invention, the time for stirring and dissolving the SB / (S→B) copolymer after mixing with the solution is 60-70 min.

[0044] In step (1) d of this invention, the coupling reaction time after adding the SB / (S→B) copolymer and mixing with the solution is 80-90 min.

[0045] In step (1) d of this invention, the time for stirring and dissolving the macromolecular complex functionalized monomer after mixing with the solvent is 70-80 min.

[0046] In step (1) d of this invention, the coupling reaction time after adding macromolecular complex functionalized monomers and solvent is 110 min to 120 min.

[0047] In step (1) d of the present invention, when the end-capping is performed, the amount of 1,3-butadiene added is 2% to 5% based on the mass of 100% of alkylstyrene.

[0048] In step (1) d of this invention, the reaction time for adding 1,3-butadiene for end-capping is 30 to 40 minutes.

[0049] In step (2)a of the present invention, the mass ratio of the nitrile rubber and the Grubbs I catalyst is 100:0.02-0.1.

[0050] In step (2)a of the present invention, the mass fraction of nitrile rubber in the adhesive solution is 3% to 6%.

[0051] In step (2)a of the present invention, the mass concentration of GrubbsⅠ catalyst in the xylene solution of the GrubbsⅠ catalyst is 5% to 10%.

[0052] In step (2)a of the present invention, the pressure is increased to 11-14 MPa; the temperature is increased to 100-120°C; and the reaction time is 9-11 hours.

[0053] In step (2)a of the present invention, the degree of hydrogenation of the HNBR rubber is less than 90%.

[0054] In step (2)b of the present invention, the mass ratio of the HNBR rubber, the macromolecular three-arm star-shaped composite functionalized grafting agent, and chlorobenzene is 100:2-4:50-100.

[0055] In step (2)b of the present invention, the mass fraction of HNBR rubber in the adhesive solution is 6% to 9%.

[0056] In step (2)b of the present invention, the reaction temperature is 80-90°C and the time is 11.0-12.0hr.

[0057] In step (2)b of the present invention, the grafting rate of the special oilfield hydrogenated nitrile rubber is 1.7% to 3.5%.

[0058] The polymerization reactions described in this invention are carried out in an oxygen-free, anhydrous, and inert gas environment. The inert gas is nitrogen or a gas of a group 0 element in the periodic table, excluding radon, with nitrogen being preferred.

[0059] The reaction vessel described in this invention can be a loop reactor or a batch reactor, preferably a batch reactor.

[0060] In step (2)a of this invention, pressurization is achieved by adding hydrogen gas. The amount of hydrogen gas added is well known to those skilled in the art, and the amount of hydrogen gas added is within the conventional addition range in the prior art. This invention does not impose any special limitations on this.

[0061] The present invention also provides a special hydrogenated nitrile butadiene rubber for oilfields obtained by the above preparation method.

[0062] Compared with the prior art, the present invention has at least the following advantages and beneficial effects:

[0063] (1) The macromolecular composite functionalized monomer prepared by the present invention is prepared by anionic polymerization of 2,4,6-trihydroxyphenylallyl ether and 4-hydroxy-3-alkoxy-1-propenylbenzene. This monomer integrates alkoxy, polyhydroxy and ether groups on a macromolecular chain, making full use of the "cumulative effect" of macromolecules, the "group effect" of ether groups, polyhydroxy and alkoxy groups, and at the same time, it produces a certain "synergistic effect" with the three-hetero-arm star structure, which can more effectively reduce the glass transition temperature (Tg) of HNBR, and can prepare special oilfield hydrogenated nitrile rubber with a glass transition temperature Tg < -80℃, which is suitable for oil well operations under low temperature conditions of -80℃.

[0064] (2) The macromolecular three-arm star-shaped composite functionalized grafting agent prepared by the present invention integrates the alkyl styrene homopolymer segment, SB / (S→B) copolymer and macromolecular composite functionalized monomer on a macromolecular chain. It makes full use of the "cumulative effect" of alkylbenzene in the alkylbenzene homopolymer and the "group effect" of phenyl in SB / (S→B copolymer and macromolecular composite functionalized monomer to produce a certain "synergistic effect". It avoids the destruction of the crystallinity of HNBR by macromolecular composite functionalized monomer, which would lead to a decrease in the tear strength of HNBR. At the same time, it can more effectively improve the tear strength of HNBR. It can prepare a special oilfield hydrogenated nitrile rubber with a raw rubber tear strength ≥78KN / m, which can meet the tear strength requirements of submersible screw pump stator rubber material during oil well operation.

[0065] (3) This invention uses a three-arm star structure design to combine three different microstructure segments on a macromolecular chain to form a three-arm star structure. This allows the properties of different segments to be organically combined and work synergistically. By utilizing the wide vinyl distribution in the BR segments, the randomness and gradation of the -SB / (S→B)- segments, and the different polymerization rates and steric hindrance effects of each segment in the three-arm structure, the disorder of the molecular chain segments increases during the graft polymerization of HNBR, which significantly destroys the regularity of the molecular chain and makes the molecular weight distribution significantly wider. This ensures that HNBR can obtain good viscoelastic properties and greatly improves the compression set resistance of HNBR. It can prepare special oilfield hydrogenated nitrile rubber with a compression set of ≤9.0% for raw rubber, which can meet the compression set resistance requirements of submersible screw pump stator rubber materials during oil well operations.

[0066] (4) The macromolecular three-arm star-shaped composite functionalized grafting agent can significantly improve the tear strength, compression set resistance and reduce the glass transition temperature (Tg) of HNBR with low addition amount, and achieve a good "synergistic effect" in achieving a balance between the tear strength, compression set resistance and cold resistance of HNBR.

[0067] (5) The preparation method of the special oilfield hydrogenated nitrile rubber of the present invention has the characteristics of being green and environmentally friendly, having a high efficiency of modification effect, low amount of modifier, readily available raw materials, and being suitable for industrial production. Detailed Implementation

[0068] The following examples and comparative examples illustrate the inventive effects of the present invention, but the scope of protection of the present invention is not limited to these examples and comparative examples. The raw materials used in the examples are all industrial grade, purified before use, and have no other special requirements. The "parts" mentioned in the examples and comparative examples refer to parts by weight.

[0069] (1) Source of raw materials:

[0070] Nitrile rubber 2907, acrylonitrile content 27%–30%, produced by Lanzhou Petrochemical Company of China National Petroleum Corporation.

[0071]

[0072] (2) Analysis and testing methods:

[0073] Grafting rate determination: Approximately 4g of sample was pipetted from a three-necked flask into a weighing bottle. After weighing, 2-3 drops of hydroquinone solution were added, and the sample was dried to constant weight. The sample was then placed in a Soxhlet extractor and extracted with toluene in a 90°C water bath for 24 hours, followed by drying to constant weight. The monomer grafting rate was calculated using the following formula:

[0074]

[0075] Where: m0—total mass of adhesive (g); m—mass of the sample taken after reaction (g); m m —Total mass of monomers in the reactants (g); m HNBR —The mass of hydrogenated nitrile rubber in the sample (g); m1—The mass of the sample after extraction (g).

[0076] Molecular weight and distribution determination: Molecular weight and distribution were determined using a Waters 2414 gel permeation chromatography (GPC) system (Waters, Inc., USA). A polystyrene standard was used as the calibration curve. The mobile phase was tetrahydrofuran, the column temperature was 40℃, the sample concentration was 1 mg / mL, the injection volume was 50 μL, the elution time was 40 min, and the flow rate was 1 mL / min. -1 .

[0077] Determination of HNBR hydrogenation degree: using nuclear magnetic resonance hydrogen spectroscopy (NMR spectroscopy). 1 The degree of hydrogenation of hydrogenated nitrile butadiene rubber (NMR) is calculated using the following main methods: 1. The product is completely dissolved in deuterated chloroform to prepare a 1H NMR sample; 2. The 1H NMR spectrum is measured and analyzed: The degree of hydrogenation of hydrogenated nitrile butadiene rubber is determined by 1H NMR spectroscopy and calculated using the following methods: characteristic proton peak of 1,4-C=C-: 5.4 ppm, characteristic proton peak of 1,2-C=C-: 5.0 ppm, characteristic proton peak of saturated hydrocarbons: 1.25 ppm, characteristic proton peak of cyano-linked groups: 2.5 ppm. The formula for calculating the degree of hydrogenation is as follows:

[0078] Degree of hydrogenation (HD%) = 1 - Degree of unsaturation (U)

[0079] Determination of glass transition temperature (Tg): The glass transition temperature of the product was measured using DSC. The instrument model was DSC1, manufactured by Mettler AG, Switzerland. The heating range was -80 to 80 °C, and the heating rate was 10 °C / min.

[0080] Tear strength: The method specified in standard GB / T 529-2009 shall be applied.

[0081] Compression set: The method specified in standard GB / T 7759.1-2015 shall be followed.

[0082] Example 1

[0083] (1) Preparation of macromolecular three-hetero-arm star-shaped composite functionalized grafting agent:

[0084] Preparation of 2,4,6-trihydroxyphenylallyl ether: First, in a 5L stainless steel polymerization reactor with a jacket, argon gas was purged three times. Then, 1500 g of deionized water, 500 g of 2,4,6-tribromophenylallyl ether, and 100 g of 10% NaOH aqueous solution were added to the polymerization reactor in sequence. The mixture was stirred, mixed, and heated to 130°C. After reacting for 6.0 hours, the mixture was finally extracted, separated, washed, and dried to obtain 2,4,6-trihydroxyphenylallyl ether (yield 80%).

[0085] b. Preparation of macromolecular composite functionalized monomers: In a 10L stainless steel polymerization reactor with a jacket, the system was purged three times with argon gas. 2000g of cyclohexane, 300g of 4-hydroxy-3-alkoxy-1-propenylbenzene, 700g of 2,4,6-trihydroxyphenyl allyl ether, and 3.0g of THF were added to the polymerization reactor in sequence. The temperature was raised to 70℃, and then 320mmol of n-butyllithium was added to the polymerization reactor and reacted for 90min. Finally, 20g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was continued for 30min until no free monomers were present. The solution was then wet-coagulated and dried to obtain the macromolecular composite functionalized monomers.

[0086] Preparation of c SB / (S→B) copolymer: In a jacketed 10L stainless steel polymerization reactor, the system was purged three times with argon gas. 1500g of cyclohexane and 0.5g of THF were added to the polymerization reactor in sequence. The temperature was raised to 60℃, and 170mmol of n-butyllithium was added. Then, 500g of 1,3-butadiene and 150g of styrene were stirred and mixed for 20min. The mixture was then continuously added to the polymerization reactor at an initial feeding rate of 80g / min, with the feeding rate decreasing by 4g per minute. The reaction was continued for 70min until no free monomers were present. The solution was wet-coagulated and dried to obtain a random, long gradient segment SB / (S→B) copolymer.

[0087] Preparation of macromolecular three-heteroarm star-shaped composite functionalized grafting agent: In a jacketed 10L stainless steel polymerization reactor, the system was purged three times with argon gas. 2000g cyclohexane, 1000g p-methylstyrene, and 3.0g THF were added sequentially to the reactor. After heating to 50℃, 195mmol of n-butyllithium was added to initiate the reaction for 80min, forming p-methylstyrene segments. Then, 500g 1,3-butadiene and 0.5g THF were added sequentially to the reactor. After heating to 60℃, the temperature was gradually increased from 60℃ to 90℃ over a 40min reaction period, forming BR segments with a broad vinyl distribution. Subsequently, 65mmol of 1,3,5-trichlorobenzene was added, and the coupling reaction was carried out for 60min. Finally, 200g of... The SB / (S→B) copolymer was mixed with 1000g of cyclohexane and stirred for 60min until completely dissolved. The mixture was then added to a polymerization reactor for a coupling reaction for 80min. Subsequently, 50g of macromolecular composite functionalized monomer and 500g of cyclohexane were mixed and stirred for 70min until completely dissolved. The mixture was then added to a polymerization reactor for a coupling reaction for 110min. Finally, 20g of 1,3-butadiene was added to the polymerization reactor for a capping reaction for 30min until no free monomers were present. The solution was then wet-coagulated and dried to obtain a macromolecular three-hetero-arm star-shaped composite functionalized grafting agent (Mn = 7000, Mw / Mn = 13.17).

[0088] (2) Preparation of hydrogenated nitrile butadiene rubber for special oilfield applications:

[0089] Preparation of hydrogenated nitrile butadiene rubber (HNBR): First, 100g of nitrile butadiene rubber 2907 was dissolved in chlorobenzene solution to prepare a 3% (w / w) rubber solution. Then, the rubber solution was added to a 10L high-pressure reactor, and nitrogen gas was introduced to remove air from the reactor. Next, hydrogen gas was used to purge the nitrogen from the reactor for 30 minutes. Then, under nitrogen protection, 0.02g of xylene solution containing Grubbs I catalyst (w / w) was added. The hydrogen pressure in the reactor was increased to 11MPa, and the temperature was raised to 100℃. After reacting for 9.0 hours, the system was cooled, condensed, and vacuum dried to obtain HNBR rubber (hydrogenation degree HD = 84.1%).

[0090] Preparation of hydrogenated nitrile butadiene rubber (HNBR) for special oilfields: First, 200g of HNBR rubber was dissolved in a chlorobenzene solution to prepare a 6% (by mass) rubber solution. Then, the rubber solution was added to a 10L stainless steel reactor with a jacket, and nitrogen gas was introduced to purge the solution three times. Next, 4.0g of a macromolecular three-arm star-shaped composite functionalized grafting agent was added to the reactor, stirred and heated. When the reactor temperature reached 80℃, a mixture of 0.10g of DCP and 100g of chlorobenzene was added. After reacting for 11.0 hours, the mixture was flocculated with anhydrous ethanol, washed, and dried in a 70℃ oven to constant weight to obtain hydrogenated nitrile butadiene rubber (grafting rate 1.7%) for special oilfields.

[0091] Example 2

[0092] (1) Preparation of macromolecular three-hetero-arm star-shaped composite functionalized grafting agent:

[0093] Preparation of α-2,4,6-trihydroxyphenylallyl ether: Same as in Example 1.

[0094] b. Preparation of macromolecular complex functionalized monomers: Same as in Example 1.

[0095] Preparation of c SB / (S→B) copolymer: Same as in Example 1.

[0096] Preparation of macromolecular three-heteroarm star-shaped composite functionalized grafting agent: In a jacketed 10L stainless steel polymerization reactor, the system was purged three times with argon gas. 2200g cyclohexane, 1000g p-methylstyrene, and 3.5g THF were added sequentially to the reactor. After heating to 52℃, 191mmol of n-butyllithium was added to initiate the reaction for 82min, forming p-methylstyrene segments. Then, 520g 1,3-butadiene and 0.6g THF were added sequentially to the reactor. After heating to 60℃, the temperature was gradually increased from 60℃ to 90℃ over a 45min reaction period, forming BR segments with a broad vinyl distribution. Subsequently, 63mmol of 1,3,5-trichlorobenzene was added, and the coupling reaction was carried out for 62min. Then, 220g of cyclohexane, 1000g p-methylstyrene, and 3.5g THF were added to the reactor. The SB / (S→B) copolymer was mixed with 1200g of cyclohexane and stirred for 62min until completely dissolved. The mixture was then added to the polymerization reactor for a coupling reaction for 82min. Subsequently, 60g of macromolecular composite functionalized monomer and 600g of cyclohexane were mixed and stirred for 72min until completely dissolved. The mixture was then added to the polymerization reactor for a coupling reaction for 112min. Finally, 30g of 1,3-butadiene was added to the polymerization reactor for a capping reaction for 32min until no free monomers were present. The solution was then wet-coagulated and dried to obtain a macromolecular three-hetero-arm star-shaped composite functionalized grafting agent (Mn = 7100, Mw / Mn = 13.42).

[0097] (2) Preparation of hydrogenated nitrile butadiene rubber for special oilfield applications:

[0098] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 1.

[0099] Preparation of hydrogenated nitrile butadiene rubber (HNBR) for special oilfields: First, 200g of HNBR rubber was dissolved in a chlorobenzene solution to prepare a 6.7% (by mass) rubber solution. Then, the solution was added to a 10L stainless steel reactor with a jacket, and nitrogen was introduced to purge the solution three times. Next, 5.0g of a macromolecular three-arm star-shaped composite functionalized grafting agent was added to the reactor, stirred and heated. When the reactor temperature reached 82℃, a mixture of 0.15g of DCP and 120g of chlorobenzene was added. After reacting for 11.2 hours, the mixture was flocculated with anhydrous ethanol, washed, and dried in a 70℃ oven to constant weight to obtain hydrogenated nitrile butadiene rubber (grafting rate 2.1%) for special oilfields.

[0100] Example 3

[0101] (1) Preparation of macromolecular three-hetero-arm star-shaped composite functionalized grafting agent:

[0102] Preparation of α-2,4,6-trihydroxyphenylallyl ether: Same as in Example 1.

[0103] b. Preparation of macromolecular complex functionalized monomers: Same as in Example 1.

[0104] Preparation of c SB / (S→B) copolymer: Same as in Example 1.

[0105] Preparation of macromolecular three-hetero-arm star-shaped composite functionalized grafting agent: In a jacketed 10L stainless steel polymerization reactor, the system was purged four times with argon gas. 2400g cyclohexane, 1000g p-methylstyrene, and 4.0g THF were added sequentially to the reactor. After heating to 54℃, 187mmol of n-butyllithium was added to initiate the reaction for 84min, forming p-methylstyrene segments. Then, 540g 1,3-butadiene and 0.7g THF were added sequentially to the reactor. After heating to 60℃, the temperature was gradually increased from 60℃ to 90℃ over a 50min reaction period, forming BR segments with a broad vinyl distribution. Subsequently, 60mmol of 1,3,5-trichlorobenzene was added, and the coupling reaction was carried out for 64min. Finally, 240g of cyclohexane, 1000g p-methylstyrene, and 4.0g THF were added to the reactor. The SB / (S→B) copolymer was mixed with 1400g of cyclohexane and stirred for 64min until completely dissolved. The mixture was then added to the polymerization reactor for a coupling reaction for 84min. Subsequently, 70g of macromolecular composite functionalized monomer and 700g of cyclohexane were mixed and stirred for 74min until completely dissolved. The mixture was then added to the polymerization reactor for a coupling reaction for 114min. Finally, 35g of 1,3-butadiene was added to the polymerization reactor for a capping reaction for 34min until no free monomers were present. The solution was then wet-coagulated and dried to obtain a macromolecular three-hetero-arm star-shaped composite functionalized grafting agent (Mn = 7300, Mw / Mn = 13.73).

[0106] (2) Preparation of hydrogenated nitrile butadiene rubber for special oilfield applications:

[0107] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 1.

[0108] Preparation of hydrogenated nitrile butadiene rubber (HNBR) for special oilfields: First, 200g of HNBR rubber was dissolved in chlorobenzene solution to prepare a 7.1% (by mass) rubber solution. Then, the solution was added to a 10L stainless steel reactor with a jacket, and nitrogen gas was introduced to purge the solution four times. Next, 5.5g of a macromolecular three-arm star-shaped composite functionalized grafting agent was added to the reactor, stirred and heated. When the reactor temperature reached 84℃, a mixture of 0.20g of DCP and 140g of chlorobenzene was added. After reacting for 11.4 hours, the mixture was flocculated with anhydrous ethanol, washed, and dried in a 70℃ oven to constant weight to obtain hydrogenated nitrile butadiene rubber (grafting rate 2.4%) for special oilfields.

[0109] Example 4

[0110] (1) Preparation of macromolecular three-hetero-arm star-shaped composite functionalized grafting agent:

[0111] Preparation of 2,4,6-trihydroxyphenylallyl ether: First, in a 5L stainless steel polymerization reactor with a jacket, argon gas was purged four times. Then, 2000 g of deionized water, 500 g of 2,4,6-tribromophenylallyl ether, and 150 g of 20% NaOH aqueous solution were added to the polymerization reactor in sequence. The mixture was stirred, mixed, and heated to 140°C. After reacting for 8.0 hours, the mixture was finally extracted, separated, washed, and dried to obtain 2,4,6-trihydroxyphenylallyl ether (yield 83%).

[0112] b. Preparation of macromolecular composite functionalized monomers: In a jacketed 10L stainless steel polymerization reactor, the system was purged with argon gas four times. 2600g of cyclohexane, 350g of 4-hydroxy-3-alkoxy-1-propenylbenzene, 650g of 2,4,6-trihydroxyphenyl allyl ether, and 4.3g of THF were added sequentially to the polymerization reactor. The temperature was raised to 76℃, and then 303mmol of n-butyllithium was added to the polymerization reactor and reacted for 96min. Finally, 40g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was continued for 36min until no free monomers were present. The solution was then wet-coagulated and dried to obtain the macromolecular composite functionalized monomers.

[0113] Preparation of c SB / (S→B) copolymer: In a jacketed 10L stainless steel polymerization reactor, the system was purged with argon gas four times. 1700g of cyclohexane and 1.3g of THF were added to the polymerization reactor sequentially. The temperature was raised to 64℃, and 163mmol of n-butyllithium was added. Then, 500g of 1,3-butadiene and 170g of styrene were stirred and mixed for 24min. The mixture was then continuously added to the polymerization reactor at an initial feeding rate of 65g / min, with the feeding rate decreasing by 2g per minute. The reaction was continued for 74min until no free monomers were present. The solution was then wet-coagulated and dried to obtain a random, long gradient SB / (S→B) copolymer.

[0114] Preparation of macromolecular three-heteroarm star-shaped composite functionalized grafting agent: In a jacketed 10L stainless steel polymerization reactor, the system was purged four times with argon gas. 2600g cyclohexane, 1000g p-methylstyrene, and 5.0g THF were added sequentially to the reactor. After heating to 56℃, 183mmol of n-butyllithium was added to initiate a reaction for 86min, forming p-methylstyrene segments. Then, 560g 1,3-butadiene and 0.8g THF were added sequentially to the reactor. After heating to 60℃, the temperature was gradually increased from 60℃ to 90℃ over a 55min reaction period, forming BR segments with a broad vinyl distribution. Subsequently, 56mmol of 1,3,5-trichlorobenzene was added, and the coupling reaction was carried out for 66min. Then, 260g of cyclohexane, 1000g p-methylstyrene, and 5.0g THF were added to the reactor. The SB / (S→B) copolymer was mixed with 1600g of cyclohexane and stirred for 66min until completely dissolved. The mixture was then added to a polymerization reactor for a coupling reaction for 86min. Subsequently, 80g of macromolecular composite functionalized monomer and 800g of cyclohexane were mixed and stirred for 76min until completely dissolved. The mixture was then added to a polymerization reactor for a coupling reaction for 116min. Finally, 40g of 1,3-butadiene was added to the polymerization reactor for a capping reaction for 36min until no free monomers were present. The solution was then wet-coagulated and dried to obtain a macromolecular three-hetero-arm star-shaped composite functionalized grafting agent (Mn = 7500, Mw / Mn = 14.01).

[0115] (2) Preparation of hydrogenated nitrile butadiene rubber for special oilfield applications:

[0116] Preparation of hydrogenated nitrile butadiene rubber (HNBR): First, 100g of nitrile butadiene rubber 2907 was dissolved in chlorobenzene solution to prepare a 4.5% (w / w) rubber solution. Then, the rubber solution was added to a 10L high-pressure reactor, and nitrogen gas was introduced to remove air from the reactor. Next, hydrogen gas was used to purge the nitrogen from the reactor for 36 min. Then, under nitrogen protection, 0.07g of xylene solution containing Grubbs I catalyst (w / w) was added. The hydrogen pressure in the reactor was increased to 12MPa, and the temperature was raised to 113℃. After reacting for 10 h, the system was cooled, condensed, and vacuum dried to obtain HNBR rubber (hydrogenation degree HD = 87.1%).

[0117] Preparation of hydrogenated nitrile butadiene rubber (HNBR) for special oilfields: First, 200g of HNBR rubber was dissolved in a chlorobenzene solution to prepare a 7.8% (by mass) rubber solution. Then, the solution was added to a 10L stainless steel reactor with a jacket, and nitrogen gas was introduced to purge the solution four times. Next, 6.0g of a macromolecular three-arm star-shaped composite functionalized grafting agent was added to the reactor, stirred and heated. When the reactor temperature reached 86℃, a mixture of 0.30g of DCP and 160g of chlorobenzene was added. After reacting for 11.5 hours, the mixture was flocculated with anhydrous ethanol, washed, and dried in a 70℃ oven to constant weight to obtain hydrogenated nitrile butadiene rubber (grafting rate 2.7%) for special oilfields.

[0118] Example 5

[0119] (1) Preparation of macromolecular three-hetero-arm star-shaped composite functionalized grafting agent:

[0120] Preparation of α-2,4,6-trihydroxyphenylallyl ether: Same as in Example 4.

[0121] b. Preparation of macromolecular complex functionalized monomers: Same as in Example 4.

[0122] Preparation of c SB / (S→B) copolymer: Same as in Example 4.

[0123] Preparation of macromolecular three-hetero-arm star-shaped composite functionalized grafting agent: In a jacketed 10L stainless steel polymerization reactor, the system was purged five times with argon gas. 2800g cyclohexane, 1000g p-methylstyrene, and 5.5g THF were added sequentially to the reactor. After heating to 58℃, 176mmol of n-butyllithium was added to initiate a reaction for 87min, forming p-methylstyrene segments. Then, 580g 1,3-butadiene and 0.9g THF were added sequentially to the reactor. After heating to 60℃, the temperature was gradually increased from 60℃ to 90℃ over a 57min reaction period, forming BR segments with a broad vinyl distribution. Subsequently, 51mmol of 1,3,5-trichlorobenzene was added, and the coupling reaction was carried out for 68min. Then, 280g of cyclohexane, 1000g p-methylstyrene, and 5.5g THF were added to the reactor. The SB / (S→B) copolymer was mixed with 1800g of cyclohexane and stirred for 68min until completely dissolved. The mixture was then added to a polymerization reactor for a coupling reaction for 87min. Subsequently, 90g of macromolecular composite functionalized monomer and 900g of cyclohexane were mixed and stirred for 78min until completely dissolved. The mixture was then added to a polymerization reactor for a coupling reaction for 117min. Finally, 46g of 1,3-butadiene was added to the polymerization reactor for a capping reaction for 38min until no free monomers were present. The solution was then wet-coagulated and dried to obtain a macromolecular three-hetero-arm star-shaped composite functionalized grafting agent (Mn = 7700, Mw / Mn = 14.29).

[0124] (2) Preparation of hydrogenated nitrile butadiene rubber for special oilfield applications:

[0125] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 4.

[0126] Preparation of hydrogenated nitrile butadiene rubber (HNBR) for special oilfields: First, 200g of HNBR rubber was dissolved in a chlorobenzene solution to prepare a rubber solution with a mass fraction of 8.2%. Then, the rubber solution was added to a 10L stainless steel reactor with a jacket, and nitrogen gas was introduced to purge the solution five times. Next, 7.0g of a macromolecular three-hetero-arm star-shaped composite functionalized grafting agent was added to the reactor, stirred and mixed, and heated. When the reactor temperature reached 88℃, a mixture of 0.35g of DCP and 180g of chlorobenzene was added. After reacting for 11.7 hours, the mixture was flocculated with anhydrous ethanol, washed, and dried in a 70℃ oven to constant weight to obtain hydrogenated nitrile butadiene rubber (grafting rate 3.0%) for special oilfields.

[0127] Example 6

[0128] (1) Preparation of macromolecular three-hetero-arm star-shaped composite functionalized grafting agent:

[0129] Preparation of α-2,4,6-trihydroxyphenylallyl ether: Same as in Example 4.

[0130] b. Preparation of macromolecular composite functionalized monomers: In a 10L stainless steel polymerization reactor with a jacket, the system was purged with argon gas five times. 3000g of cyclohexane, 400g of 4-hydroxy-3-alkoxy-1-propenylbenzene, 600g of 2,4,6-trihydroxyphenyl allyl ether, and 5.0g of THF were added to the polymerization reactor sequentially. The temperature was raised to 80℃, and then 289 mmol of n-butyllithium was added to the polymerization reactor and reacted for 100 min. Finally, 50g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was continued for 40 min until no free monomers were present. The solution was then wet-coagulated and dried to obtain the macromolecular composite functionalized monomers.

[0131] Preparation of c SB / (S→B) copolymer: In a jacketed 10L stainless steel polymerization reactor, the system was purged with argon five times. 2000g of cyclohexane and 2.0g of THF were added to the polymerization reactor sequentially. The temperature was raised to 70℃, and 149mmol of n-butyllithium was added. Then, 500g of 1,3-butadiene and 200g of styrene were stirred and mixed for 30min. The mixture was then continuously added to the polymerization reactor at an initial feeding rate of 65g / min, with the feeding rate decreasing by 2g per minute. The reaction was carried out for 80min until no free monomers were present. The solution was wet-coagulated and dried to obtain a random, long gradient segment SB / (S→B) copolymer.

[0132] Preparation of macromolecular three-heteroarm star-shaped composite functionalized grafting agent: In a jacketed 10L stainless steel polymerization reactor, the system was purged five times with argon gas. 3000g cyclohexane, 1000g p-methylstyrene, and 6.0g THF were added sequentially to the reactor. After heating to 60℃, 171mmol of n-butyllithium was added to initiate a 90min reaction, forming p-methylstyrene segments. Then, 600g 1,3-butadiene and 1.0g THF were added sequentially to the reactor. After heating to 60℃, the temperature was gradually increased from 60℃ to 90℃ over a 60min reaction period, forming BR segments with a broad vinyl distribution. Subsequently, 48mmol of 1,3,5-trichlorobenzene was added, and the coupling reaction was carried out for 70min. Finally, 300g of... The SB / (S→B) copolymer was mixed with 2000g of cyclohexane and stirred for 70min until completely dissolved. The mixture was then added to a polymerization reactor for a coupling reaction for 90min. Subsequently, 100g of macromolecular composite functionalized monomer and 1000g of cyclohexane were mixed and stirred for 80min until completely dissolved. The mixture was then added to a polymerization reactor for a coupling reaction for 120min. Finally, 50g of 1,3-butadiene was added to the polymerization reactor for a capping reaction for 40min until no free monomers were present. The solution was then wet-coagulated and dried to obtain a macromolecular three-hetero-arm star-shaped composite functionalized grafting agent (Mn = 8000, Mw / Mn = 14.67).

[0133] (2) Preparation of hydrogenated nitrile butadiene rubber for special oilfield applications:

[0134] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 4.

[0135] Preparation of hydrogenated nitrile butadiene rubber (HNBR) for special oilfields: First, 200g of HNBR rubber was dissolved in a chlorobenzene solution to prepare a 9.0% (by mass) rubber solution. Then, the solution was added to a 10L stainless steel reactor with a jacket, and nitrogen gas was introduced to purge the solution five times. Next, 8.0g of a macromolecular three-arm star-shaped composite functionalized grafting agent was added to the reactor, stirred and heated. When the reactor temperature reached 90℃, a mixture of 0.40g of DCP and 200g of chlorobenzene was added. After reacting for 12.0 hours, the mixture was flocculated with anhydrous ethanol, washed, and dried in a 70℃ oven to constant weight to obtain hydrogenated nitrile butadiene rubber (grafting rate 3.5%) for special oilfields.

[0136] Comparative Example 1

[0137] (1) Preparation of macromolecular three-hetero-arm star-shaped composite functionalized grafting agent:

[0138] Preparation of α-2,4,6-trihydroxyphenylallyl ether: Same as in Example 1.

[0139] b. Preparation of macromolecular complex functionalized monomers: Same as in Example 1.

[0140] Preparation of c SB / (S→B) copolymer: Same as in Example 1.

[0141] Preparation of macromolecular three-heteroarm star-shaped composite functionalized grafting agent: Other conditions were the same as in Example 1, except that the preparation of the macromolecular three-heteroarm star-shaped composite functionalized grafting agent did not use a temperature-switching polymerization method. That is, in a jacketed 10L stainless steel polymerization reactor, the system was purged three times with argon gas. 2000g of cyclohexane, 1000g of p-methylstyrene, and 3.0g of THF were added to the polymerization reactor sequentially. After heating to 50°C, 195mmol of n-butyllithium was added to initiate the reaction for 80min, forming p-methylstyrene segments. Then, 500g of 1,3-butadiene and 0.5g of THF were added to the polymerization reactor sequentially. After heating to 60°C, the reaction was initiated for 40min, forming BR segments. Subsequently, 65mmol of 1,3,5-trichlorobenzene was added, and the coupling reaction was carried out for 60min. Then, 200g of cyclohexane, 1000g of p-methylstyrene, and 3.0g of THF were added to the polymerization reactor sequentially. The SB / (S→B) copolymer was mixed with 1000g of cyclohexane and stirred for 60min until completely dissolved. The mixture was then added to a polymerization reactor for a coupling reaction for 80min. Subsequently, 50g of macromolecular composite functionalized monomer and 500g of cyclohexane were mixed and stirred for 70min until completely dissolved. The mixture was then added to a polymerization reactor for a coupling reaction for 110min. Finally, 20g of 1,3-butadiene was added to the polymerization reactor for a capping reaction for 30min until no free monomers were present. The solution was then wet-coagulated and dried to obtain macromolecular three-hetero-arm star-shaped composite functionalized grafting agent a (Mn = 6900, Mw / Mn = 11.31).

[0142] (2) Preparation of hydrogenated nitrile butadiene rubber for special oilfield applications:

[0143] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 1.

[0144] Preparation of hydrogenated nitrile butadiene rubber (NBR) for special oilfields: Other conditions are the same as in Example 1, except that no macromolecular tri-arm star-shaped composite functionalized grafting agent is added during the preparation of hydrogenated nitrile butadiene rubber for special oilfields. Instead, macromolecular tri-arm star-shaped composite functionalized grafting agent a is added, with an addition amount of 4.0 g. Specifically: First, 200 g of HNBR rubber is dissolved in chlorobenzene solution to prepare a 6% by mass solution. Then, the solution is added to a 10 L stainless steel reactor with a jacket, and nitrogen is introduced to purge it three times. Then, 4.0 g of macromolecular tri-arm star-shaped composite functionalized grafting agent a is added to the reactor, stirred and mixed, and heated. When the reactor temperature reaches 80 °C, a mixture of 0.10 g of DCP and 100 g of chlorobenzene is added. After reacting for 11.0 h, the mixture is flocculated with anhydrous ethanol, washed, and dried in a 70 °C oven to constant weight to obtain hydrogenated nitrile butadiene rubber for special oilfields (grafting rate 1.6%).

[0145] Comparative Example 2

[0146] (1) Preparation of macromolecular three-hetero-arm star-shaped composite functionalized grafting agent:

[0147] Preparation of α-2,4,6-trihydroxyphenylallyl ether: Same as in Example 2.

[0148] b. Preparation of macromolecular complex functionalized monomers: Same as in Example 2.

[0149] c. Preparation of SB / (S→B) copolymer: Other conditions are the same as in Example 2, except that variable-speed polymerization is not used in the preparation of SB / (S→B) copolymer. That is, in a 10L stainless steel polymerization reactor with a jacket, the system is purged with argon gas three times. 1500g of cyclohexane and 0.5g of THF are added to the polymerization reactor in sequence. The temperature is raised to 60°C, and 170mmol of n-butyllithium is added. Then, 500g of 1,3-butadiene and 150g of styrene are stirred and mixed for 20min and then added to the polymerization reactor together and reacted for 70min until no free monomers are present. The solution is wet coagulated and dried to obtain SBR copolymer.

[0150] Preparation of macromolecular three-heteroarm star-shaped composite functionalized grafting agent: Other conditions were the same as in Example 2, except that instead of adding SB / (S→B) copolymer, SBR copolymer was added in the preparation process of macromolecular three-heteroarm star-shaped composite functionalized grafting agent. The amount added was 220.0 g. That is, in a jacketed 10L stainless steel polymerization reactor, the system was purged with argon gas three times. 2200 g of cyclohexane, 1000 g of p-methylstyrene, and 3.5 g of THF were added to the polymerization reactor in sequence. After heating to 52°C, 191 mmol of n-butyllithium was added to start the reaction for 82 min to form p-methylstyrene segments. Then, 520 g of 1,3-butadiene and 0.6 g of THF were added to the polymerization reactor in sequence. After heating to 60°C, the temperature was gradually increased from 60°C to 90°C within a 45 min reaction time to form BR segments with a wide vinyl distribution. Subsequently, 63 mmol of cyclohexane was added to the reaction reactor. 1,3,5-Trichlorobenzene was coupled for 62 min; then 220 g of SBR and 1200 g of cyclohexane were mixed and stirred for 62 min until completely dissolved, and then added to the polymerization reactor for coupling reaction for 82 min; subsequently, 60 g of macromolecular composite functionalized monomer and 600 g of cyclohexane were mixed and stirred for 72 min until completely dissolved, and then added to the polymerization reactor for coupling reaction for 112 min; finally, 30 g of 1,3-butadiene was added to the polymerization reactor for end-capping reaction for 32 min until no free monomers were present. The solution was wet coagulated and dried to obtain macromolecular three-hetero-arm star-shaped composite functionalized grafting agent b (Mn is 7000, Mw / Mn is 10.08).

[0151] (2) Preparation of hydrogenated nitrile butadiene rubber for special oilfield applications:

[0152] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 2.

[0153] Preparation of hydrogenated nitrile butadiene rubber (NBR) for special oilfields: Other conditions are the same as in Example 2, except that no macromolecular tri-arm star-shaped composite functionalized grafting agent is added during the preparation of hydrogenated nitrile butadiene rubber for special oilfields. Instead, macromolecular tri-arm star-shaped composite functionalized grafting agent b is added, with an addition amount of 5.0 g. Specifically: First, 200 g of HNBR rubber is dissolved in chlorobenzene solution to prepare a 6.7% by mass solution. Then, the solution is added to a 10 L stainless steel reactor with a jacket, and nitrogen is introduced to purge it three times. Then, 5.0 g of macromolecular tri-arm star-shaped composite functionalized grafting agent b is added to the reactor, stirred and mixed, and heated. When the reactor temperature reaches 82 °C, a mixture of 0.15 g of DCP and 120 g of chlorobenzene is added. After reacting for 11.2 hours, the mixture is flocculated with anhydrous ethanol, washed, and dried in a 70 °C oven to constant weight to obtain hydrogenated nitrile butadiene rubber for special oilfields (grafting rate 1.9%).

[0154] Comparative Example 3

[0155] (1) Preparation of macromolecular three-hetero-arm star-shaped composite functionalized grafting agent:

[0156] Preparation of α-2,4,6-trihydroxyphenylallyl ether: Same as in Example 3.

[0157] b. Preparation of macromolecular complex functionalized monomers: Same as in Example 3.

[0158] Preparation of c SB / (S→B) copolymer: Same as in Example 3.

[0159] Preparation of macromolecular three-hetero-arm star-shaped composite functionalized grafting agent: Other conditions were the same as in Example 3, except that 1,3,5-trichlorobenzene was not added during the preparation of the macromolecular three-hetero-arm star-shaped composite functionalized grafting agent. Specifically, in a jacketed 10L stainless steel polymerization reactor, the system was purged four times with argon gas. 2400g of cyclohexane, 1000g of p-methylstyrene, and 4.0g of THF were added sequentially to the polymerization reactor. After heating to 54°C, 187mmol of n-butyllithium was added to initiate the reaction for 84 minutes, forming p-methylstyrene segments. Then, 540g of 1,3-butadiene and 0.7g of THF were added sequentially to the polymerization reactor. After heating to 60°C, the temperature was gradually increased from 60°C to 90°C over a 50-minute reaction time, forming BR segments with a broad vinyl distribution. Then, 240g of... The SB / (S→B) copolymer was mixed with 1400g of cyclohexane and stirred for 64min until completely dissolved. The mixture was then added to the polymerization reactor for a coupling reaction for 84min. Subsequently, 70g of macromolecular composite functionalized monomer and 700g of cyclohexane were mixed and stirred for 74min until completely dissolved. The mixture was then added to the polymerization reactor for a coupling reaction for 114min. Finally, 35g of 1,3-butadiene was added to the polymerization reactor for a capping reaction for 34min until no free monomers were present. The solution was then wet-coagulated and dried to obtain macromolecular three-hetero-arm star-shaped composite functionalized grafting agent c (Mn is 4100, Mw / Mn is 9.87).

[0160] (2) Preparation of hydrogenated nitrile butadiene rubber for special oilfield applications:

[0161] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 3.

[0162] Preparation of hydrogenated nitrile butadiene rubber (NBR) for special oilfields: Other conditions are the same as in Example 3, except that no macromolecular tri-arm star-shaped composite functionalized grafting agent is added during the preparation of hydrogenated nitrile butadiene rubber for special oilfields. Instead, macromolecular tri-arm star-shaped composite functionalized grafting agent c is added, with an addition amount of 5.5g. Specifically: First, 200g of HNBR rubber is dissolved in chlorobenzene solution to prepare a 7.1% by mass solution. Then, the solution is added to a 10L stainless steel reactor with a jacket, and nitrogen is introduced to purge it four times. Then, 5.5g of macromolecular tri-arm star-shaped composite functionalized grafting agent c is added to the reactor, stirred and mixed, and heated. When the reactor temperature reaches 84°C, a mixture of 0.20g of DCP and 140g of chlorobenzene is added. After reacting for 11.4 hours, the mixture is flocculated with anhydrous ethanol, washed, and dried in a 70°C oven to constant weight to obtain hydrogenated nitrile butadiene rubber for special oilfields (grafting rate 2.3%).

[0163] Comparative Example 4

[0164] (1) Preparation of macromolecular three-hetero-arm star-shaped composite functionalized grafting agent:

[0165] Preparation of 2,4,6-trihydroxyphenylallyl ether: First, in a 5L stainless steel polymerization reactor with a jacket, argon gas was purged four times. Then, 2000 g of deionized water, 500 g of 2,4,6-tribromophenylallyl ether, and 150 g of 20% NaOH aqueous solution were added to the polymerization reactor in sequence. The mixture was stirred, mixed, and heated to 140°C. After reacting for 8.0 hours, the mixture was finally extracted, separated, washed, and dried to obtain 2,4,6-trihydroxyphenylallyl ether (yield 83%).

[0166] Preparation of b SB / (S→B) copolymer: Same as in Example 4.

[0167] Preparation of macromolecular three-hetero-arm star-shaped composite functionalized grafting agent: Other conditions are the same as in Example 4, except that no macromolecular composite functionalized monomer is added during the preparation of the macromolecular three-hetero-arm star-shaped composite functionalized grafting agent. Instead, 2,4,6-trihydroxyphenyl allyl ether is added in an amount of 80g. That is, in a jacketed 10L stainless steel polymerization reactor, the system is purged with argon gas four times. 2600g of cyclohexane, 1000g of p-methylstyrene, and 5.0g of THF are added to the polymerization reactor in sequence. After heating to 56°C, 183mmol of n-butyllithium is added to start the reaction for 86min, forming p-methylstyrene segments. Then, 560g of 1,3-butadiene and 0.8g of THF are added to the polymerization reactor in sequence. After heating to 60°C, the temperature is gradually increased from 60°C to 90°C within a 55min reaction time to form BR segments with a wide vinyl distribution. Subsequently, 56mmol of cyclohexane is added to the reaction reactor. 1,3,5-Trichlorobenzene was coupled for 66 min; then 260 g of SB / (S→B) copolymer and 1600 g of cyclohexane were mixed and stirred for 66 min until completely dissolved, and then added to the polymerization reactor for coupling reaction for 86 min; subsequently, 80 g of 2,4,6-trihydroxyphenyl allyl ether and 800 g of cyclohexane were mixed and stirred for 76 min until completely dissolved, and then added to the polymerization reactor for coupling reaction for 116 min; finally, 40 g of 1,3-butadiene was added to the polymerization reactor for end-capping reaction for 36 min until no free monomers were present. The solution was wet coagulated and dried to obtain macromolecular three-hetero-arm star-shaped composite functionalized grafting agent d (Mn is 5600, Mw / Mn is 12.07).

[0168] (2) Preparation of hydrogenated nitrile butadiene rubber for special oilfield applications:

[0169] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 4.

[0170] Preparation of hydrogenated nitrile butadiene rubber (NBR) for special oilfields: Other conditions are the same as in Example 4, except that no macromolecular tri-arm star-shaped composite functionalized grafting agent is added during the preparation of hydrogenated nitrile butadiene rubber for special oilfields. Instead, macromolecular tri-arm star-shaped composite functionalized grafting agent d is added, with an addition amount of 6.0 g. Specifically: First, 200 g of HNBR rubber is dissolved in chlorobenzene solution to prepare a 7.8% by mass solution. Then, the solution is added to a 10 L stainless steel reactor with a jacket, and nitrogen is introduced to purge it four times. Then, 6.0 g of macromolecular tri-arm star-shaped composite functionalized grafting agent d is added to the reactor, stirred and mixed, and heated. When the reactor temperature reaches 86 °C, a mixture of 0.30 g of DCP and 160 g of chlorobenzene is added. After reacting for 11.5 hours, the mixture is flocculated with anhydrous ethanol, washed, and dried in a 70 °C oven to constant weight to obtain hydrogenated nitrile butadiene rubber for special oilfields (grafting rate 1.6%).

[0171] Comparative Example 5

[0172] (1) Preparation of macromolecular three-hetero-arm star-shaped composite functionalized grafting agent:

[0173] Preparation of α-2,4,6-trihydroxyphenylallyl ether: Same as in Example 5.

[0174] b. Preparation of macromolecular complex functionalized monomers: Same as in Example 5.

[0175] Preparation of c SB / (S→B) copolymer: Same as in Example 5.

[0176] Preparation of macromolecular three-hetero-arm star-shaped composite functionalized grafting agent: Other conditions were the same as in Example 5, except that p-methylstyrene was not added during the preparation of the macromolecular three-hetero-arm star-shaped composite functionalized grafting agent. Instead, styrene was added. Specifically, in a 10L stainless steel polymerization reactor with a jacket, the system was purged with argon gas five times. 2800g of cyclohexane, 1000g of styrene, and 5.5g of THF were added to the polymerization reactor sequentially. After heating to 58°C, 176mmol of n-butyllithium was added to initiate the reaction for 87min, forming p-methylstyrene segments. Then, 580g of 1,3-butadiene and 0.9g of THF were added to the polymerization reactor sequentially. After heating to 60°C, the temperature was gradually increased from 60°C to 90°C over a 57min reaction period, forming BR segments with a broad vinyl distribution. Subsequently, 51mmol of 1,3,5-trichlorobenzene was added, and the coupling reaction was carried out for 68min. Then, 280g of cyclohexane, 1000g of styrene, and 5.5g of THF were added to the polymerization reactor sequentially. The SB / (S→B) copolymer was mixed with 1800g of cyclohexane and stirred for 68min until completely dissolved. The mixture was then added to the polymerization reactor for a coupling reaction for 87min. Subsequently, 90g of macromolecular composite functionalized monomer and 900g of cyclohexane were mixed and stirred for 78min until completely dissolved. The mixture was then added to the polymerization reactor for a coupling reaction for 117min. Finally, 46g of 1,3-butadiene was added to the polymerization reactor for a capping reaction for 38min until no free monomers were present. The solution was then wet-coagulated and dried to obtain macromolecular three-hetero-arm star-shaped composite functionalized grafting agent e (Mn = 7200, Mw / Mn = 12.98).

[0177] (2) Preparation of hydrogenated nitrile butadiene rubber for special oilfield applications:

[0178] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 5.

[0179] Preparation of hydrogenated nitrile butadiene rubber (NBR) for special oilfields: Other conditions are the same as in Example 5, except that no macromolecular tri-arm star-shaped composite functionalized grafting agent is added during the preparation of hydrogenated nitrile butadiene rubber for special oilfields. Instead, macromolecular tri-arm star-shaped composite functionalized grafting agent e is added, with an addition amount of 7.0g. Specifically: First, 200g of HNBR rubber is dissolved in chlorobenzene solution to prepare a glue solution with a mass fraction of 8.2%. Then, the glue solution is added to a 10L stainless steel reactor with a jacket, and nitrogen is introduced to replace it 5 times. Then, 7.0g of macromolecular tri-arm star-shaped composite functionalized grafting agent e is added to the reactor, stirred and mixed, and heated. When the reactor temperature reaches 88°C, a mixture of 0.35g of DCP and 180g of chlorobenzene is added. After reacting for 11.7 hours, the mixture is flocculated with anhydrous ethanol, washed, and dried in a 70°C oven to constant weight to obtain hydrogenated nitrile butadiene rubber for special oilfields (grafting rate 2.8%).

[0180] Comparative Example 6

[0181] (1) Preparation of macromolecular three-hetero-arm star-shaped composite functionalized grafting agent:

[0182] Preparation of α-2,4,6-trihydroxyphenylallyl ether: Same as in Example 6.

[0183] b. Preparation of macromolecular complex functionalized monomers: Same as in Example 6.

[0184] Preparation of macromolecular three-heteroarm star-shaped composite functionalized grafting agent: Other conditions were the same as in Example 6, except that SB / (S→B) copolymer was not added during the preparation of the macromolecular three-heteroarm star-shaped composite functionalized grafting agent. That is, in a jacketed 10L stainless steel polymerization reactor, the system was purged with argon gas 5 times, and 3000g of cyclohexane and 6.0g of THF were added to the polymerization reactor in sequence. After heating to 60°C, 171 mmol was added, followed by 600g of 1,3-butadiene and 1.0g of THF. After heating to 60°C, the temperature was gradually increased from 60°C to 90°C within a 60min reaction time to form BR segments with a wide vinyl distribution. Then 48 mmol was added. 1,3,5-Trichlorobenzene was coupled for 70 min; then 100 g of macromolecular composite functionalized monomer and 1000 g of cyclohexane were mixed and stirred for 80 min until completely dissolved, and then added to a polymerization reactor for a coupling reaction for 120 min; finally, 50 g of 1,3-butadiene was added to the polymerization reactor for a capping reaction for 40 min until no free monomers were present. The solution was then wet-coagulated and dried to obtain a macromolecular two-heteroarm star-shaped composite functionalized grafting agent (Mn = 5800, Mw / Mn = 8.15).

[0185] (2) Preparation of hydrogenated nitrile butadiene rubber for special oilfield applications:

[0186] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 6.

[0187] Preparation of hydrogenated nitrile butadiene rubber (NBR) for special oilfields: Other conditions are the same as in Example 6, except that a macromolecular three-arm star-shaped composite functionalized grafting agent is not added during the preparation of hydrogenated nitrile butadiene rubber for special oilfields. Instead, a macromolecular two-arm star-shaped composite functionalized grafting agent is added, with an addition amount of 8.0 g. Specifically: First, 200 g of HNBR rubber is dissolved in chlorobenzene solution to prepare a 9.0% by mass solution. Then, the solution is added to a 10 L stainless steel reactor with a jacket, and nitrogen is introduced to purge five times. Next, 8.0 g of macromolecular two-arm star-shaped composite functionalized grafting agent is added to the reactor, stirred and mixed, and heated. When the reactor temperature reaches 90 °C, a mixture of 0.40 g of DCP and 200 g of chlorobenzene is added. After reacting for 12.0 h, the mixture is flocculated with anhydrous ethanol, washed, and dried in a 70 °C oven to constant weight to obtain hydrogenated nitrile butadiene rubber for special oilfields (grafting rate 3.0%).

[0188] Table 1. Performance of Hydrogenated Nitrile Butadiene Rubber for Special Oilfield Use

[0189]

[0190] As shown in Table 1, the special hydrogenated nitrile butadiene rubber for oilfields of the present invention has high tear strength, low compression set and low glass transition temperature. When used as a stator rubber material for submersible screw pumps, it can meet the requirements of oil well operations under low temperature conditions of -80℃.

[0191] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a special type of hydrogenated nitrile butadiene rubber for oilfield use, characterized in that, Includes the following steps: (1) Preparation of macromolecular three-hetero-arm star-shaped composite functionalized grafting agent: Preparation of 2,4,6-trihydroxyphenylallyl ether: Argon gas was introduced into the polymerization reactor for purging. Deionized water, 2,4,6-tribromophenylallyl ether, and NaOH aqueous solution were added sequentially to the polymerization reactor. The mixture was stirred, mixed, heated, and allowed to react. Finally, the mixture was extracted, separated, washed, and dried to obtain 2,4,6-trihydroxyphenylallyl ether. The mass ratio of the deionized water, 2,4,6-tribromophenylallyl ether, and NaOH aqueous solution was 300~400:100:20~30. b. Preparation of macromolecular composite functionalized monomers: In a polymerization reactor, argon gas is introduced to purge the system. Solvent, 4-hydroxy-3-alkoxy-1-propenylbenzene, 2,4,6-trihydroxyphenylallyl ether, and structure modifier are added sequentially to the polymerization reactor. The temperature is raised, and initiator 1 is added to the polymerization reactor for reaction. Finally, 1,3-butadiene is added to the polymerization reactor for end-capping. The reaction continues until no free monomers are present. The solution is wet-coagulated and dried to obtain macromolecular composite functionalized monomers. The mass ratio of the solvent, 4-hydroxy-3-alkoxy-1-propenylbenzene, 2,4,6-trihydroxyphenylallyl ether, structure modifier, and 1,3-butadiene is 200~300:30~40:60~70:0.3~0.5:2~5. Preparation of c SB / (S→B) copolymer: Argon gas was introduced into the polymerization reactor to purge the system. Solvent and structure modifier were added to the polymerization reactor in sequence, the temperature was raised, initiator 1 was added, and then 1,3-butadiene and styrene were stirred and mixed and added to the polymerization reactor. The reaction was continued until no free monomers were present. The glue solution was wet coagulated and dried to obtain random, long gradient segment SB / (S→B) copolymer; the mass ratio of solvent, structure modifier, 1,3-butadiene and styrene was 300~400:0.1~0.4:100:30~40. Preparation of d-macromolecule three-heteroarm star-shaped composite functionalized grafting agent: In a polymerization reactor, argon gas was introduced to purge the system. Solvent 1, p-alkylstyrene, and a first-stage structure modifier were added sequentially to the reactor. The temperature was raised, and initiator 1 was added to react and form p-alkylstyrene homopolymer segments. Then, 1,3-butadiene and a second-stage structure modifier were added sequentially to the reactor. The temperature was raised, and the reaction was a temperature-switching polymerization. The temperature was gradually increased from 60℃ to 90℃ within 40-60 min to form BR segments with a broad vinyl distribution. Subsequently, a coupling agent was added to carry out a coupling reaction. Then, SB / (S→B) was added. The copolymer and solution were mixed and stirred until completely dissolved, then added to the polymerization reactor for coupling reaction. Finally, the macromolecular composite functionalized monomer was mixed with solvent 2 and stirred until completely dissolved, then added to the polymerization reactor for coupling reaction. 1,3-Butadiene was then added to the polymerization reactor for end-capping, and the reaction continued until no free monomer remained. After the reaction was complete, the coupled reaction mixture was treated with water, and the resulting solution was wet-coagulated and dried to obtain a macromolecular three-heteroarm star-shaped composite functionalized grafting agent. The coupling agent was one of 1,3,5-trichlorobenzene and 1,3,5-tribromobenzene. The solvent 1 consisted of p-alkylstyrene, a primary structure modifier, 1,3-butadiene, a secondary structure modifier, and SB / (S→B). The mass ratio of copolymer, solution, macromolecular complex functionalized monomer, and solvent 2 is 200~300:100:0.3~0.6:50~60:0.05~0.1:20~30:100~200:5~10:50~100; (2) Preparation of hydrogenated nitrile butadiene rubber for special oilfields: Preparation of hydrogenated nitrile butadiene rubber (HNBR): Nitrile butadiene rubber is dissolved in chlorobenzene solution to prepare a rubber solution. The rubber solution is then added to a reaction vessel, and an inert gas is introduced to remove the air from the reaction vessel. After the inert gas in the reaction vessel is removed by hydrogen, a xylene solution of Grubbs I catalyst is added under nitrogen protection. The pressure is increased and the temperature is raised. After the reaction, the system is cooled, condensed, and vacuum dried to obtain HNBR rubber. b. Preparation of hydrogenated nitrile butadiene rubber for special oilfields: HNBR rubber is dissolved in chlorobenzene solution to prepare a rubber solution. The rubber solution is then added to a reaction vessel, and an inert gas is introduced for purging. A macromolecular three-arm star-shaped composite functionalized grafting agent is then added to the reaction vessel. The mixture is stirred, heated, and a mixture of initiator 2 and chlorobenzene is added. After the reaction, the mixture is flocculated, washed, and dried to obtain hydrogenated nitrile butadiene rubber for special oilfields. The macromolecular three-hetero-arm star-shaped composite functionalized grafting agent has the following structure: Wherein, R is a C1-C6 straight-chain alkyl group; BR is a 1,3-butadiene homopolymer segment with a broad vinyl distribution; B is a capped 1,3-butadiene; n, m, and L are the number of repeating units, where n≥1, m≥1, and L≥1 are positive integers; the number average molecular weight (Mn) of the macromolecular tri-hetero-arm star-shaped composite functionalized grafting agent is 7000-8000, and the molecular weight distribution (Mw / Mn) is 13.17-14.

67.

2. The preparation method according to claim 1, characterized in that, The p-alkylstyrene is selected from one of p-methylstyrene, p-ethylstyrene, p-propylstyrene, p-butylstyrene, p-pentylstyrene, and p-hexylstyrene.

3. The preparation method according to claim 1, characterized in that, The 4-hydroxy-3-alkoxy-1-propenylbenzene is selected from one of 4-hydroxy-3-methoxy-1-propenylbenzene, 4-hydroxy-3-ethoxy-1-propenylbenzene, 4-hydroxy-3-propoxy-1-propenylbenzene, 4-hydroxy-3-butoxy-1-propenylbenzene, 4-hydroxy-3-pentoxy-1-propenylbenzene, and 4-hydroxy-3-hexyloxy-1-propenylbenzene.

4. The preparation method according to claim 1, characterized in that, The initiator 1 is selected from one of n-butyllithium, sec-butyllithium, methylbutyllithium, phenylbutyllithium, naphthalenelithium, cyclohexyllithium, and dodecyllithium.

5. The preparation method according to claim 1, characterized in that, The initiator 2 is selected from one of diacetyl peroxide, diisobutyryl peroxide, cumene hydroperoxide, diisobutyryl peroxide (DCP), and benzoyl peroxide (BPO), and its addition amount is 0.05 to 0.2 parts based on 100 parts by weight of HNBR rubber.

6. The preparation method according to claim 1, characterized in that, The nitrile rubber is copolymerized from 1,3-butadiene and acrylonitrile through emulsion polymerization, wherein the acrylonitrile content of the nitrile rubber is 20wt% to 42wt%.

7. The preparation method according to claim 1, characterized in that, The structure modifier is selected from one of diethylene glycol dimethyl ether (2G), tetrahydrofuran (THF), ethyl ether, ethyl methyl ether, anisole, diphenyl ether, diethylene glycol dimethyl ether (DME), and triethylamine.

8. The preparation method according to claim 1, characterized in that, The solvent, solvent 1, solvent 2, or solution is selected from one of cyclohexane, carbon disulfide (CS2), nitrobenzene, petroleum ether, tetrachloroethane, toluene, and xylene.

9. The preparation method according to claim 1, characterized in that, In step (1)a, the mass concentration of the NaOH aqueous solution is 10%~20%.

10. The preparation method according to claim 1, characterized in that, In step (1)a, the yield of the 2,4,6-trihydroxyphenylallyl ether is 80%~83%.

11. The preparation method according to claim 1, characterized in that, In step (1) d, during the end-capping process, the amount of 1,3-butadiene added is 2% to 5% based on the mass of alkylstyrene as 100%.

12. The preparation method according to claim 1, characterized in that, In step (2)a, the mass ratio of the nitrile rubber to the Grubbs I catalyst is 100:0.02~0.

1.

13. The preparation method according to claim 1, characterized in that, In step (2)a, the degree of hydrogenation of the HNBR rubber is less than 90%.

14. The preparation method according to claim 1, characterized in that, In step (2)b, the mass ratio of the HNBR rubber, the macromolecular three-arm star-shaped composite functionalized grafting agent, and chlorobenzene is 100:2~4:50~100.

15. The preparation method according to claim 1, characterized in that, In step (2)b, the grafting rate of the special oilfield hydrogenated nitrile rubber is 1.7% to 3.5%.

16. A special hydrogenated nitrile butadiene rubber for oilfield use obtained by the preparation method according to any one of claims 1-15.

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