Pressure-resistant and cold-resistant hydrogenated nitrile rubber for oil field and preparation method thereof

Abstract

The application discloses oilfield compression-resistant and cold-resistant hydrogenated butyl nitrile rubber and a preparation method thereof, and the preparation method comprises the following steps: (1) preparing a composite functionalized macromolecular long-branch linking branch agent; and (2) preparing the oilfield compression-resistant and cold-resistant hydrogenated butyl nitrile rubber; the composite functionalized macromolecular long-branch linking branch agent has the following structure: wherein IR is an isoprene homopolymer segment with a wide ethylene group distribution; SB is a random segment of styrene and 1,3-butadiene; (S->B) is a gradual change segment of styrene and butadiene; B is a blocked 1,3-butadiene; n is a repeating unit number, and n is a positive integer greater than or equal to 1; the number average molecular weight (Mn) of the composite functionalized macromolecular long-branch linking branch agent is 6000-8000, and the molecular weight distribution (Mw / Mn) is 9.13-10.86. The preparation method of the oilfield compression-resistant and cold-resistant hydrogenated butyl nitrile rubber 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] This invention belongs to the field of rubber technology, specifically relating to a compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber for oilfields modified with a composite functionalized macromolecular long-branched linker and its preparation method. Background Technology

[0002] Hydrogenated nitrile butadiene rubber (HNBR) is prepared by selectively hydrogenating the carbon-carbon double bonds in nitrile butadiene 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. Furthermore, its mechanical properties such as tensile strength, elongation at break, abrasion resistance and hardness are improved. It is widely used in oil exploration equipment such as pump pistons, rotary hoses, valve seals, and drill pipe covers.

[0003] While hydrogenation of the carbon-carbon double bonds endows HNBR with excellent properties, it also introduces a serious drawback: the main chain of hydrogenated nitrile butadiene rubber (NBR) is a highly ordered polyethylene structure, which readily forms a crystalline structure, leading to an increase in temperature (Tg). Consequently, HNBR products exhibit poor cold resistance. Since most of my country's oil drilling operations are concentrated in the western and northeastern regions, where minimum temperatures can reach around -50°C, oil drilling equipment faces extremely demanding cold resistance requirements for rubber sealing materials.

[0004] In the prior art, there are many patent documents reporting methods for preparing low-temperature resistant hydrogenated nitrile butadiene rubber. For example:

[0005] CN 106349410 B discloses a special hydrogenated nitrile butadiene rubber with compression cold resistance and its preparation method. The rubber backbone contains epoxy groups, and some of these epoxy groups are also attached to ester side groups. The ester side groups are generated by a ring-opening reaction between a C6-C24 acid anhydride and the epoxy groups. The preparation method includes introducing epoxy groups into the rubber molecular backbone, and then reacting some of the epoxy groups with an acid anhydride under the action of a catalyst to introduce ester groups, thereby obtaining a special hydrogenated nitrile butadiene rubber containing epoxy groups and ester groups. N 105294939B discloses a low-temperature grade hydrogenated nitrile butadiene rubber raw rubber, which is a copolymer of butadiene, acrylonitrile, and dibutyl transbutenedioate, with a number-average molecular weight of 1.05–3.25 × 10⁻⁶. 5 The weight-average molecular weight is 3.02–9.32 × 10⁻⁶. 5The polydispersity index is 2.0–2.7; the degree of hydrogenation of the low-temperature grade hydrogenated nitrile butadiene rubber raw rubber is above 90%, and the glass transition temperature is -38℃ to -42℃. CN 112592461 B discloses a modified hydrogenated nitrile butadiene rubber material with low-temperature resistance and high damping characteristics, its preparation method, and its application. The modified hydrogenated nitrile butadiene rubber material is prepared using HNBR / PNB block copolymer as raw material; the HNBR / PNB block copolymer is obtained by modifying NBR or HNBR through olefin metathesis reaction using norbornene monomer as a modifier. CN 115594898A discloses a low-temperature resistant hydrogenated nitrile butadiene rubber compound and its internal mixing preparation method. The method mainly involves blending and internal mixing hydrogenated nitrile butadiene raw rubber, plasticizer, and hardness modifier to obtain a hydrogenated nitrile butadiene rubber compound with a Shore A hardness of 67±5, tensile strength ≥14MPa, elongation at break ≥180%, compression set ≤35%, and a cold resistance coefficient at 45℃ ≥0.16, exhibiting cold resistance. CN 105754164A discloses a low-temperature resistant rubber material. Although this material shows improved cold resistance, the addition of the plasticizer dioctyl phthalate (DOP) reduces the material's mechanical properties and oil resistance. Furthermore, DOP is not environmentally friendly and is prone to leaching. Zhang Dongheng et al. disclosed that by blending ethylene propylene rubber (EPDM) with HNBR, the cold resistance of HNBR was improved. When the EPDM content was 15%, the Tg decreased by 3°C. However, with further increasing the EPDM content, the Tg of the blended rubber no longer decreased (Synthetic Rubber Industry, 2002, 25(1)). ).

[0006] While the cold resistance of hydrogenated nitrile butadiene rubber can be improved to some extent by adding small molecule modifiers, copolymerization, and blending, these methods still have limitations. Their preparation methods are complex, difficult to implement, require large amounts of additives, are costly, and have limited modification effects. Summary of the Invention

[0007] To address the problems existing in the prior art, this invention provides a method for preparing compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber (NBR) for oilfield use, with a compression set ≤16% and a glass transition temperature (Tg) <-71℃, meeting the requirements for use in the range of -71℃ to -74℃. The invention first uses dihydromyrcenol and N-(4-hydroxybutyl)acrylamide to prepare a composite functionalized macromolecular long-chain monomer via anionic polymerization. Second, using anionic polymerization, the reactants are isoprene, styrene, 1,3-butadiene, and the composite functionalized macromolecular long-chain monomer, which are then subjected to temperature-varying and speed-varying polymerization to prepare a composite functionalized macromolecular long-branched grafting agent with a broad vinyl distribution and random gradient segments, exhibiting free radical reactivity. Finally, the composite functionalized macromolecular long-branched grafting agent is grafted onto the main chain of hydrogenated NBR to prepare the compression-resistant and cold-resistant hydrogenated NBR for oilfield use. This method not only solves the problem of easy crystallization of hydrogenated nitrile butadiene rubber, but also greatly improves the viscoelasticity of hydrogenated nitrile butadiene rubber, making it exhibit excellent deformation resistance and cold resistance. It achieves a balance between the deformation resistance and low temperature resistance of hydrogenated nitrile butadiene rubber, making it very suitable for oil well operations with compression requirements.

[0008] Unless otherwise specified, the term "parts" in this invention refers to parts by mass, "%" refers to percentage by mass, and "ratio" refers to mass ratio.

[0009] To achieve the above objectives, the present invention provides a method for preparing compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber for oil fields, the method comprising the following steps:

[0010] (1) Preparation of composite functionalized macromolecular long-branched linking agents:

[0011] Preparation of a composite functionalized macromolecular long-chain monomer: Argon gas was introduced into the polymerization reactor to replace the system. Solvent, dihydromyrcenol, N-(4-hydroxybutyl)acrylamide, and structure modifier were added to the polymerization reactor in sequence. The temperature was raised, and initiator 1 was added to the polymerization reactor for reaction. Finally, 1,3-butadiene was added to the polymerization reactor for end-capping. The reaction continued until no free monomers were present. The gel solution was wet coagulated and dried to obtain the composite functionalized macromolecular long-chain monomer.

[0012] b. Preparation of 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.

[0013] Preparation of the composite functionalized macromolecular long-branched linker: In a polymerization reactor, argon gas is introduced to purge the system. Solvent, isoprene, and the first structure modifier are added sequentially to the polymerization reactor. The temperature is raised, and initiator 1 is added. The reaction is a temperature-switching polymerization, in which the temperature is gradually increased from 50℃ to 80℃ within 60-70 minutes to form IR segments with a wide vinyl distribution. Then, the SB / (S→B) copolymer and the composite functionalized macromolecular long-chain monomer are mixed with the solution and stirred until completely dissolved. Then, the mixture is added to the polymerization reactor along with the second structure modifier 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 then wet-coagulated and dried to obtain the composite functionalized macromolecular long-branched linker.

[0014] (2) Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber for oil fields:

[0015] 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, the reaction is carried out, the system is cooled, condensed, and dried to obtain HNBR rubber.

[0016] Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber for 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. Then, a composite functionalized macromolecular long-branched linking agent is added to the reaction vessel, stirred and mixed, heated, and a mixture of initiator 2 and chlorobenzene is added. The reaction proceeds, followed by flocculation, washing, and drying to obtain compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber for oilfields.

[0017] The composite functionalized macromolecular long-branched linker has the following structure:

[0018]

[0019] Wherein, IR is a homopolymer segment of isoprene with a broad vinyl distribution; SB is a random segment of styrene and 1,3-butadiene; (S→B) is a gradient segment of styrene and butadiene; B is a terminated 1,3-butadiene; n is the number of repeating units, and n is a positive integer ≥ 1; the number average molecular weight (Mn) of the composite functionalized macromolecular long-branched linker is 6000-8000, and the molecular weight distribution (Mw / Mn) is 9.13-10.86.

[0020] 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.

[0021] 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 BPO, and its addition amount is 0.05 to 0.15 parts based on 100 parts by weight of HNBR rubber.

[0022] 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%.

[0023] 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 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).

[0024] The solvent 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.

[0025] In step (1)a of the present invention, the mass ratio of the solvent, dihydromyrcenol, N-(4-hydroxybutyl)acrylamide, structure modifier, and 1,3-butadiene is 200-300:60-70:30-40:0.1-0.3:2-5.

[0026] In step (1)a of the present invention, the temperature is raised to 50-60°C.

[0027] In step (1)a of the present invention, the reaction time after adding initiator 1 is 70-80 min.

[0028] In step (1)a of the present invention, the reaction time for adding 1,3-butadiene for end-capping is 30 to 40 minutes.

[0029] In step (1)b 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.

[0030] In step (1)b of the present invention, the temperature is raised to the reaction temperature of 60-70°C.

[0031] In step (1)b of the present invention, 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.

[0032] In step (1)c of the present invention, the mass ratio of the solvent, isoprene, primary structure modifier, SB / (S→B) copolymer and composite functionalized macromolecular long-chain monomer, solution, secondary structure modifier and 1,3-butadiene is 200%~300:100:0.05~0.2:30~40:5~10:300~400:0.2~0.5:2~5.

[0033] In step (1)c of the present invention, the stirring and dissolving time is 50-60 min.

[0034] In step (1)c of the present invention, the reaction time after adding the second structure modifier is 90-100 min, and the reaction time for adding 1,3-butadiene for end-capping is 20-30 min.

[0035] 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.

[0036] In step (2)a of the present invention, the mass fraction of nitrile rubber in the adhesive solution is 3% to 6%.

[0037] 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%.

[0038] 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.

[0039] In step (2)a of the present invention, the degree of hydrogenation of the HNBR rubber is less than 90%.

[0040] In step (2)b of the present invention, the mass ratio of the HNBR rubber, the composite functionalized macromolecular long-branched linker, and chlorobenzene is 100:2-8:50-100.

[0041] In step (2)b of the present invention, the mass fraction of HNBR rubber in the adhesive solution is 6% to 9%.

[0042] In step (2)b of the present invention, the reaction temperature is 80-90°C and the time is 8.0-10.0hr.

[0043] In step (2)b of the present invention, the grafting rate of the oilfield-use compression-resistant and cold-resistant hydrogenated nitrile rubber is 2.2% to 3.1%.

[0044] 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.

[0045] The reaction vessel described in this invention can be a loop reactor or a batch reactor, preferably a batch reactor.

[0046] 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.

[0047] The present invention also provides a compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber for oil fields obtained by the above preparation method.

[0048] Compared with the prior art, the present invention has at least the following advantages and beneficial effects:

[0049] (1) The SB / (S→B) copolymer prepared in this invention is mainly prepared by anionic polymerization of the reactive monomers 1,3-butadiene and styrene through variable-speed polymerization to produce a random, segmental SB / (S→B) copolymer. This copolymer utilizes the "structural effect" of the randomness of SB and the gradual change of the long chain segments of (S→B) and the "accumulation effect" of macromolecules to significantly broaden the molecular weight distribution of HNBR, which can significantly improve the viscoelasticity of HNBR. At the same time, it achieves a good "synergistic effect" with the wide distribution of unsaturated "carbon-carbon" double bonds of IR in improving the viscoelasticity of HNBR, greatly reducing the compression set of HNBR. It can be used to prepare compression set ≤16% of raw rubber for oilfield use of compression-resistant and cold-resistant hydrogenated nitrile rubber.

[0050] (2) The composite functionalized macromolecular long-chain monomer prepared by the present invention is prepared by anionic polymerization of dihydromyrcenol and N-(4-hydroxybutyl)acrylamide. This long-chain monomer integrates ether groups, amide groups and hydroxyl groups containing long carbon chains into a macromolecular chain, making full use of the "cumulative effect" of macromolecules and the "group effect" of hydroxyl and amide groups. It can effectively destroy the crystallinity of HNBR and effectively reduce the glass transition temperature (Tg) of HNBR. It can prepare oilfield compression-resistant and cold-resistant hydrogenated nitrile rubber with a glass transition temperature Tg < -71℃, which is suitable for oil well operations under low temperature conditions of -71℃.

[0051] (3) The composite functionalized macromolecular long-branched grafting agent prepared by the present invention can significantly improve the compression set resistance of HNBR and reduce the glass transition temperature (Tg) of HNBR with a low addition amount, and achieve a good "synergistic effect" in achieving a balance between compression set resistance and cold resistance.

[0052] (4) The preparation method of the oilfield compression-resistant and cold-resistant 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

[0053] 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.

[0054] (1) Source of raw materials:

[0055]

[0056] (2) Analysis and testing methods:

[0057] 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:

[0058]

[0059] 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).

[0060] Molecular weight determination: Molecular weight was 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 .

[0061] 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:

[0062] Degree of hydrogenation (HD%) = 1 - Degree of unsaturation (U)

[0063] 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.

[0064] Compression set: The method specified in standard GB / T 7759.1-2015 shall be followed.

[0065] Example 1

[0066] (1) Preparation of composite functionalized macromolecular long-branched linking agents:

[0067] Preparation of composite functionalized macromolecular long-chain monomers: In a 10L stainless steel polymerization reactor with a jacket, the system was purged three times with argon gas. 1000g cyclohexane, 300g dihydromyrcenol, 200g N-(4-hydroxybutyl)acrylamide, and 0.5g THF were added to the polymerization reactor in sequence. The temperature was raised to 50℃, and then 150mmol n-butyllithium was added to the polymerization reactor and reacted for 70min. Finally, 10g 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 composite functionalized macromolecular long-chain monomers.

[0068] b. Preparation of 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 70g / min, with the feeding rate decreasing by 3g per minute. The reaction was continued for 70min until no free monomers were present. The solution was then wet-coagulated and dried to obtain a random, long gradient segment SB / (S→B) copolymer.

[0069] Preparation of c-composite functionalized macromolecular long-chain branching agent: In a jacketed 10L stainless steel polymerization reactor, the system was purged three times with argon gas. 1000g cyclohexane, 500g isoprene, and 0.25g THF were added sequentially to the reactor. After heating to 50℃, 93mmol n-butyllithium was added to initiate the reaction. Within 60min, the temperature was gradually increased from 50℃ to 80℃, forming IR segments with a broad vinyl distribution. Then, 150g of SB / (S→B) copolymer and 25g of the composite functionalized macromolecular long-chain monomer were mixed with 1500g cyclohexane and stirred for 50min until completely dissolved. This mixture was then added to the polymerization reactor along with 1.0g THF and reacted for 90min. Finally, 10.0g of [unspecified substance] was added to the polymerization reactor. 1,3-Butadiene was capped and reacted for 20 minutes until no free monomers were present. The solution was then wet-coagulated and dried to obtain a composite functionalized macromolecular long-branched linker (Mn = 6000, Mw / Mn = 9.13).

[0070] (2) Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber for oil fields:

[0071] 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%).

[0072] Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber (NBR) for oilfield use: First, 200g of HNBR rubber was dissolved in a chlorobenzene solution to prepare a 6% (by mass) rubber solution. Then, the solution was added to a 10L stainless steel reactor with a jacket, and nitrogen was introduced three times for purging. Next, 4.0g of a composite functionalized macromolecular long-branched grafting agent was added to the reactor, stirred, and heated. When the reactor temperature reached 80℃, a mixture of 0.10g BPO and 100g chlorobenzene was added. After reacting for 8.0 hours, the mixture was flocculated with anhydrous ethanol, washed, and dried in a 70℃ oven to constant weight to obtain compression-resistant and cold-resistant hydrogenated NBR for oilfield use (grafting rate 2.2%). Sampling and analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0073] Example 2

[0074] (1) Preparation of composite functionalized macromolecular long-branched linking agents:

[0075] Preparation of composite functionalized macromolecular long-chain monomers: In a 10L stainless steel polymerization reactor with a jacket, the system was purged three times with argon gas. 1100g of cyclohexane, 310g of dihydromyrcenol, 190g of N-(4-hydroxybutyl)acrylamide, and 0.7g of THF were added to the polymerization reactor in sequence. The temperature was raised to 52℃, and then 147mmol of n-butyllithium was added to the polymerization reactor and reacted for 72min. Finally, 13g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was continued for 32min until no free monomers were present. The solution was then wet-coagulated and dried to obtain composite functionalized macromolecular long-chain monomers.

[0076] b. Preparation of SB / (S→B) copolymer: In a jacketed 10L stainless steel polymerization reactor, the system was purged three times with argon gas. 1600g of cyclohexane and 1.0g of THF were added to the polymerization reactor in sequence. The temperature was raised to 62℃, and 167mmol of n-butyllithium was added. Then, 500g of 1,3-butadiene and 160g of styrene were stirred and mixed for 22min. The mixture was then continuously added to the polymerization reactor at an initial feeding rate of 70g / min, with the feeding rate decreasing by 3g per minute. The reaction was carried out for 72min until no free monomers were present. The solution was wet-coagulated and dried to obtain a random, long gradient segment SB / (S→B) copolymer.

[0077] Preparation of c-composite functionalized macromolecular long-chain branching agent: In a jacketed 10L stainless steel polymerization reactor, the system was purged three times with argon gas. 1100g of cyclohexane, 500g of isoprene, and 0.45g of THF were added sequentially to the reactor. After heating to 50℃, 85mmol of n-butyllithium was added to initiate the reaction. Within 62min, the temperature was gradually increased from 50℃ to 80℃, forming IR segments with a broad vinyl distribution. Then, 160g of SB / (S→B) copolymer and 30g of the composite functionalized macromolecular long-chain monomer were mixed with 1600g of cyclohexane and stirred for 52min until completely dissolved. This mixture was then added to the polymerization reactor along with 1.5g of THF and reacted for 92min. Finally, 13.0g of [unspecified substance] was added to the polymerization reactor. 1,3-Butadiene was used for end-capping, and the reaction was carried out for 22 minutes until no free monomers were present. The solution was then wet-coagulated and dried to obtain a composite functionalized macromolecular long-branched linker (Mn is 6600, Mw / Mn is 9.54).

[0078] (2) Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber for oil fields:

[0079] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Implementation 1.

[0080] Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber (NBR) for oilfield use: First, 200g of HNBR rubber was dissolved in a chlorobenzene solution to prepare a 6.5% (by mass) rubber solution. Then, the solution was added to a 10L stainless steel reactor with a jacket, and nitrogen was introduced three times for purging. Next, 6.0g of a composite functionalized macromolecular long-branched grafting agent was added to the reactor, stirred, and heated. When the reactor temperature reached 82℃, a mixture of 0.15g BPO and 120g chlorobenzene was added. After reacting for 8.5 hours, the mixture was flocculated with anhydrous ethanol, washed, and dried in a 70℃ oven to constant weight to obtain compression-resistant and cold-resistant hydrogenated NBR for oilfield use (grafting rate 2.3%). Sampling and analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0081] Example 3

[0082] (1) Preparation of composite functionalized macromolecular long-branched linking agents:

[0083] Preparation of composite functionalized macromolecular long-chain monomers: In a 10L stainless steel polymerization reactor with a jacket, the system was purged with argon gas four times. 1200g of cyclohexane, 320g of dihydromyrcenol, 180g of N-(4-hydroxybutyl)acrylamide, and 0.9g of THF were added to the polymerization reactor in sequence. The temperature was raised to 54℃, and then 143mmol of n-butyllithium was added to the polymerization reactor and reacted for 74min. Finally, 17g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was continued for 34min until no free monomers were present. The solution was then wet-coagulated and dried to obtain composite functionalized macromolecular long-chain monomers.

[0084] b. Preparation of 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-segment SB / (S→B) copolymer.

[0085] Preparation of c-composite functionalized macromolecular long-chain branching agent: In a jacketed 10L stainless steel polymerization reactor, the system was purged four times with argon gas. 1200g of cyclohexane, 500g of isoprene, and 0.55g of THF were added sequentially to the reactor. After heating to 50℃, 80mmol of n-butyllithium was added to initiate the reaction. The temperature was gradually increased from 50℃ to 80℃ over 64min, forming IR segments with a broad vinyl distribution. Then, 170g of SB / (S→B) copolymer and 35g of the composite functionalized macromolecular long-chain monomer were mixed with 1700g of cyclohexane and stirred for 54min until completely dissolved. This mixture was then added to the polymerization reactor along with 1.7g of THF and reacted for 94min. Finally, 18.0g of [unspecified substance] was added to the polymerization reactor. 1,3-Butadiene was used for end-capping, and the reaction was carried out for 24 minutes until no free monomers were present. The solution was then wet-coagulated and dried to obtain a composite functionalized macromolecular long-branched linker (Mn = 7100, Mw / Mn = 9.78).

[0086] (2) Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber for oil fields:

[0087] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Implementation 1.

[0088] Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber (NBR) for oilfield use: First, 200g of HNBR rubber was dissolved in a chlorobenzene solution to prepare a 7.6% (by mass) rubber solution. Then, the solution was added to a 10L jacketed stainless steel reactor, and nitrogen was introduced to purge the mixture four times. Next, 9.0g of a composite functionalized macromolecular long-branched grafting agent was added to the reactor, stirred, and heated. When the reactor temperature reached 84℃, a mixture of 0.20g BPO and 140g chlorobenzene was added. After reacting for 9.0 hours, the mixture was flocculated with anhydrous ethanol, washed, and dried in a 70℃ oven to constant weight to obtain compression-resistant and cold-resistant hydrogenated NBR for oilfield use (grafting rate 2.5%). Sampling and analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0089] Example 4

[0090] (1) Preparation of composite functionalized macromolecular long-branched linking agents:

[0091] Preparation of composite functionalized macromolecular long-chain monomers: In a 10L stainless steel polymerization reactor with a jacket, the system was purged with argon gas four times. 1300g of cyclohexane, 330g of dihydromyrcenol, 170g of N-(4-hydroxybutyl)acrylamide, and 1.1g of THF were added to the polymerization reactor in sequence. The temperature was raised to 56℃, and then 140mmol of n-butyllithium was added to the polymerization reactor and reacted for 76min. Finally, 20g 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 composite functionalized macromolecular long-chain monomers.

[0092] b. Preparation of SB / (S→B) copolymer: In a jacketed 10L stainless steel polymerization reactor, the system was purged with argon gas four times. 1800g of cyclohexane and 1.6g of THF were added to the polymerization reactor sequentially. The temperature was raised to 66℃, and 158mmol of n-butyllithium was added. Then, 500g of 1,3-butadiene and 180g of styrene were stirred and mixed for 26min. 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 76min until no free monomers were present. The solution was wet-coagulated and dried to obtain a random, long, gradient-segment SB / (S→B) copolymer.

[0093] Preparation of c-composite functionalized macromolecular long-chain branching agent: In a jacketed 10L stainless steel polymerization reactor, the system was purged four times with argon gas. 1300g of cyclohexane, 500g of isoprene, and 0.75g of THF were added sequentially to the reactor. After heating to 50℃, 76mmol of n-butyllithium was added to initiate the reaction. Within 66min, the temperature gradually increased from 50℃ to 80℃, forming IR segments with a broad vinyl distribution. Then, 180g of SB / (S→B) copolymer and 40g of the composite functionalized macromolecular long-chain monomer were mixed with 1800g of cyclohexane and stirred for 56min until completely dissolved. This mixture was then added to the polymerization reactor along with 2.0g of THF and reacted for 96min. Finally, 20.0g of [unspecified substance] was added to the polymerization reactor. 1,3-Butadiene was used for end-capping, and the reaction was carried out for 26 minutes until no free monomers were present. The solution was then wet-coagulated and dried to obtain a composite functionalized macromolecular long-branched linker (Mn = 7500, Mw / Mn = 10.13).

[0094] (2) Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber for oil fields:

[0095] 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%).

[0096] Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber (NBR) for oilfield use: First, 200g of HNBR rubber was dissolved in a chlorobenzene solution to prepare a rubber solution with a mass fraction of 8.1%. Then, the rubber solution was added to a 10L stainless steel reactor with a jacket, and nitrogen gas was introduced to purge the solution four times. Next, 11.0g of a composite functionalized macromolecular long-branched grafting agent was added to the reactor, stirred, and heated. When the reactor temperature reached 86℃, a mixture of 0.23g of BPO and 160g of chlorobenzene was added. After reacting for 9.2 hours, the mixture was flocculated with anhydrous ethanol, washed, and dried in a 70℃ oven to constant weight to obtain compression-resistant and cold-resistant hydrogenated NBR for oilfield use (grafting rate 2.7%). Sampling and analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0097] Example 5

[0098] (1) Preparation of composite functionalized macromolecular long-branched linking agents:

[0099] Preparation of a composite functionalized macromolecular long-chain monomer: Same as in Example 4.

[0100] b. Preparation of SB / (S→B) copolymer: In a jacketed 10L stainless steel polymerization reactor, the system was purged with argon five times. 1900g of cyclohexane and 1.8g of THF were added to the polymerization reactor sequentially. The temperature was raised to 68℃, and 152mmol of n-butyllithium was added. Then, 500g of 1,3-butadiene and 190g of styrene were stirred and mixed for 28min. 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 78min until no free monomers were present. The solution was then wet-coagulated and dried to obtain a random, long gradient segment SB / (S→B) copolymer.

[0101] Preparation of c-composite functionalized macromolecular long-chain branching agent: In a jacketed 10L stainless steel polymerization reactor, the system was purged five times with argon gas. 1400g of cyclohexane, 500g of isoprene, and 0.85g of THF were added sequentially to the reactor. After heating to 50℃, 72mmol of n-butyllithium was added to initiate the reaction. Within 68min, the temperature gradually increased from 50℃ to 80℃, forming IR segments with a broad vinyl distribution. Then, 190g of SB / (S→B) copolymer and 45g of the composite functionalized macromolecular long-chain monomer were mixed with 1900g of cyclohexane and stirred for 58min until completely dissolved. This mixture was then added to the polymerization reactor along with 2.3g of THF and reacted for 98min. Finally, 22.0g of [unspecified substance] was added to the polymerization reactor. 1,3-Butadiene was end-capped and reacted for 28 minutes until no free monomers were present. The solution was then wet-coagulated and dried to obtain a composite functionalized macromolecular long-branched linker (Mn = 7800, Mw / Mn = 10.59).

[0102] (2) Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber for oil fields:

[0103] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 4.

[0104] Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber (NBR) for oilfield use: First, 200g of HNBR rubber was dissolved in a chlorobenzene solution to prepare a rubber solution with a mass fraction of 8.5%. Then, the rubber solution was added to a 10L stainless steel reactor with a jacket, and nitrogen gas was introduced to purge five times. Next, 13.0g of a composite functionalized macromolecular long-branched grafting agent was added to the reactor, stirred, and heated. When the reactor temperature reached 88℃, a mixture of 0.26g of BPO and 180g of chlorobenzene was added. After reacting for 9.6 hours, the mixture was flocculated with anhydrous ethanol, washed, and dried in a 70℃ oven to constant weight to obtain compression-resistant and cold-resistant hydrogenated NBR for oilfield use (grafting rate 2.9%). Sampling and analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0105] Example 6

[0106] (1) Preparation of composite functionalized macromolecular long-branched linking agents:

[0107] Preparation of composite functionalized macromolecular long-chain monomers: In a 10L stainless steel polymerization reactor with a jacket, the system was purged with argon gas five times. 1500g of cyclohexane, 350g of dihydromyrcenol, 150g of N-(4-hydroxybutyl)acrylamide, and 1.5g of THF were added to the polymerization reactor in sequence. The temperature was raised to 60℃, and then 132mmol of n-butyllithium was added to the polymerization reactor and reacted for 80min. Finally, 25g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was continued for 40min until no free monomers were present. The solution was then wet-coagulated and dried to obtain the composite functionalized macromolecular long-chain monomers.

[0108] b. Preparation of 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 continued for 80min until no free monomers were present. The solution was then wet-coagulated and dried to obtain a random, long, gradient-segment SB / (S→B) copolymer.

[0109] Preparation of c-composite functionalized macromolecular long-chain branching agent: In a jacketed 10L stainless steel polymerization reactor, the system was purged five times with argon gas. 1500g of cyclohexane, 500g of isoprene, and 1.0g of THF were added sequentially to the reactor. After heating to 50℃, 70mmol of n-butyllithium was added to initiate the reaction. Within 70min, the temperature was gradually increased from 50℃ to 80℃, forming IR segments with a broad vinyl distribution. Then, 200g of SB / (S→B) copolymer and 50g of the composite functionalized macromolecular long-chain monomer were mixed with 2000g of cyclohexane and stirred for 60min until completely dissolved. This mixture was then added to the polymerization reactor along with 2.5g of THF and reacted for 100min. Finally, 25.0g of [unspecified substance] was added to the polymerization reactor. 1,3-Butadiene was end-capped and reacted for 30 minutes until no free monomers were present. The solution was then wet-coagulated and dried to obtain a composite functionalized macromolecular long-branched linker (Mn = 8000, Mw / Mn = 10.86).

[0110] (2) Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber for oil fields:

[0111] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 4.

[0112] Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber (NBR) for oilfield use: 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 was introduced to purge the solution five times. Next, 16.0g of a composite functionalized macromolecular long-branched grafting agent was added to the reactor, stirred, and heated. When the reactor temperature reached 90℃, a mixture of 0.30g BPO and 200g chlorobenzene was added. After reacting for 10.0 hours, the mixture was flocculated with anhydrous ethanol, washed, and dried in a 70℃ oven to constant weight to obtain compression-resistant and cold-resistant hydrogenated NBR for oilfield use (grafting rate 3.1%). Sampling and analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0113] Comparative Example 1

[0114] (1) Preparation of composite functionalized macromolecular long-branched linking agents:

[0115] Preparation of a complex functionalized macromolecular long-chain monomer: Same as in Example 1.

[0116] b. Preparation of SB / (S→B) copolymer: Other conditions are the same as in Example 1, except that variable-rate 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 added to the polymerization reactor for 70min until no free monomers are present. The solution is wet-coagulated and dried to obtain random, long gradient segment SB / (S→B) copolymer a.

[0117] Preparation of the composite functionalized macromolecular long-branched linker: Other conditions were the same as in Example 1, except that SB / (S→B) copolymer was not added during the preparation of the composite functionalized macromolecular long-branched linker. Instead, SB / (S→B) copolymer a was added in an amount of 150g. Specifically, in a 10L stainless steel polymerization reactor with a jacket, the system was purged with argon gas three times. 1000g of cyclohexane, 500g of isoprene, and 0.25g of THF were added to the polymerization reactor sequentially. After heating to 50°C, 93mmol of n-butyllithium was added to initiate the reaction. Within 60min, the temperature was gradually increased from 50°C to 80°C, forming IR segments with a broad vinyl distribution. Then, 150g of SB / (S→B) copolymer a and 25g of the composite functionalized macromolecular long-chain monomer were mixed with 1500g of cyclohexane and stirred for 50min until completely dissolved. Finally, 1.0g of SB / (S→B) copolymer a was added. THF was added to the polymerization reactor and reacted for 90 min. Finally, 10.0 g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was continued for 20 min until no free monomers were present. The solution was then wet-coagulated and dried to obtain the composite functionalized macromolecular long-branched linker a (Mn is 5900, Mw / Mn is 6.76).

[0118] (2) Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber for oil fields:

[0119] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 1.

[0120] Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber (NBR) for oilfields: Other conditions are the same as in Example 1, except that no composite functionalized macromolecular long-branched grafting agent is added during the preparation of NBR for oilfields. Instead, composite functionalized macromolecular long-branched grafting agent a is added, with an addition amount of 4.0g. Specifically: First, 200g of HNBR rubber is dissolved in chlorobenzene solution to prepare a 6% by mass solution. Then, the solution is added to a 10L stainless steel reactor with a jacket, and nitrogen is introduced to purge three times. Then, 4.0g of composite functionalized macromolecular long-branched grafting agent a is added to the reactor, stirred and mixed, and heated. When the reactor temperature reaches 80°C, a mixture of 0.10g of BPO and 100g of chlorobenzene is added. After reacting for 8.0hr, the mixture is flocculated with anhydrous ethanol, washed, and dried in a 70°C oven to constant weight to obtain compression-resistant and cold-resistant hydrogenated NBR for oilfields (grafting rate 1.9%). Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0121] Comparative Example 2

[0122] (1) Preparation of composite functionalized macromolecular long-branched linking agents:

[0123] Preparation of a composite functionalized macromolecular long-chain monomer: Same as Example 2.

[0124] b. Preparation of SB / (S→B) copolymer: Other conditions are the same as in Example 2, except that the amount of 1,3-butadiene added in the preparation of SB / (S→B) copolymer is 150g. That is, in a 10L stainless steel polymerization reactor with a jacket, the system is purged with argon gas three times, 1600g of cyclohexane and 1.0g of THF are added to the polymerization reactor in sequence, the temperature is raised to 62°C, 167mmol of n-butyllithium is added, and then 150g of 1,3-butadiene and 160g of styrene are stirred and mixed for 22min. Then, the mixture is continuously added to the polymerization reactor at an initial feeding rate of 70g / min, and the feeding rate is reduced by 3g of mixture per minute. The reaction is carried out for 72min until no free monomers are present. The glue solution is wet coagulated and dried to obtain random, long gradient segment SB / (S→B) copolymer b.

[0125] Preparation of the composite functionalized macromolecular long-branched linker: Other conditions were the same as in Example 2, except that SB / (S→B) copolymer was not added during the preparation of the composite functionalized macromolecular long-branched linker. Instead, SB / (S→B) copolymer b was added in an amount of 160g. Specifically, in a 10L stainless steel polymerization reactor with a jacket, the system was purged with argon gas three times. 1100g of cyclohexane, 500g of isoprene, and 0.45g of THF were added sequentially to the polymerization reactor. After heating to 50°C, 85mmol of n-butyllithium was added to initiate the reaction. Within 62min, the temperature gradually increased from 50°C to 80°C, forming IR segments with a broad vinyl distribution. Then, 160g of SB / (S→B) copolymer b and 30g of the composite functionalized macromolecular long-chain monomer were mixed with 1600g of cyclohexane and stirred for 52min until completely dissolved. Finally, 1.5g of SB / (S→B) copolymer b was added. THF was added to the polymerization reactor and reacted for 92 min. Finally, 13.0 g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was continued for 22 min until no free monomers were present. The solution was then wet-coagulated and dried to obtain the composite functionalized macromolecular long-branched linker b (Mn is 5700, Mw / Mn is 8.79).

[0126] (2) Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber for oil fields:

[0127] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 2.

[0128] Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber (NBR) for oilfields: Other conditions are the same as in Example 2, except that no composite functionalized macromolecular long-branched grafting agent is added during the preparation of NBR for oilfields. Instead, composite functionalized macromolecular long-branched grafting agent b is added, with an addition amount of 6.0g. Specifically: First, 200g of HNBR rubber is dissolved in chlorobenzene solution to prepare a 6.5% by mass solution. Then, the solution is added to a 10L stainless steel reactor with a jacket, and nitrogen is introduced to purge three times. Then, 6.0g of composite functionalized macromolecular long-branched grafting agent b is added to the reactor, stirred and mixed, and heated. When the reactor temperature reaches 82°C, a mixture of 0.15g of BPO and 120g of chlorobenzene is added. After reacting for 8.5 hours, the mixture is flocculated with anhydrous ethanol, washed, and dried in a 70°C oven to constant weight to obtain compression-resistant and cold-resistant hydrogenated NBR for oilfields (grafting rate 2.0%). Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0129] Comparative Example 3

[0130] (1) Preparation of composite functionalized macromolecular long-branched linking agents:

[0131] Preparation of a composite functionalized macromolecular long-chain monomer: Same as in Example 3.

[0132] Preparation of b SB / (S→B) copolymer: Same as in Example 3.

[0133] Preparation of the composite functionalized macromolecular long-branched linker: Other conditions were the same as in Example 3, except that the amount of SB / (S→B) copolymer added during the preparation of the composite functionalized macromolecular long-branched linker was 100g. Specifically: In a 10L stainless steel polymerization reactor with a jacket, the system was purged with argon gas four times. Then, 1200g of cyclohexane, 500g of isoprene, and 0.55g of THF were added sequentially to the polymerization reactor. After heating to 50°C, 80mmol of n-butyllithium was added to initiate the reaction. Within 64 minutes, the temperature gradually increased from 50°C to 80°C, forming IR segments with a broad vinyl distribution. Then, 100g of SB / (S→B) copolymer and 35g of the composite functionalized macromolecular long-chain monomer were mixed with 1700g of cyclohexane and stirred for 54 minutes until completely dissolved. This mixture was then added to the polymerization reactor along with 1.7g of THF and reacted for 94 minutes. Finally, 18.0g of [unspecified substance] was added to the polymerization reactor. 1,3-Butadiene was capped and reacted for 24 minutes until no free monomers were present. The solution was then wet-coagulated and dried to obtain a composite functionalized macromolecular long-branched linker c (Mn is 5600, Mw / Mn is 8.92).

[0134] (2) Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber for oil fields:

[0135] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 3.

[0136] Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber (NBR) for oilfields: Other conditions are the same as in Example 3, except that no composite functionalized macromolecular long-branched grafting agent is added during the preparation of NBR for oilfields. Instead, composite functionalized macromolecular long-branched grafting agent c is added, with an addition amount of 9.0g. Specifically: First, 200g of HNBR rubber is dissolved in chlorobenzene solution to prepare a 7.6% 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, 9.0g of composite functionalized macromolecular long-branched 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 BPO and 140g of chlorobenzene is added. After reacting for 9.0hr, the mixture is flocculated with anhydrous ethanol, washed, and dried in a 70°C oven to constant weight to obtain compression-resistant and cold-resistant hydrogenated NBR for oilfields (grafting rate 2.2%). Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0137] Comparative Example 4

[0138] (1) Preparation of composite functionalized macromolecular long-branched linking agents:

[0139] Preparation of a composite functionalized macromolecular long-chain monomer: Same as in Example 4.

[0140] Preparation of b SB / (S→B) copolymer: Same as in Example 4.

[0141] Preparation of the composite functionalized macromolecular long-branched linker: Other conditions were the same as in Example 4, except that the synthesis of the IR segment in the preparation of the composite functionalized macromolecular long-branched linker did not use temperature-switched polymerization. Specifically, in a 10L stainless steel polymerization reactor with a jacket, the system was purged with argon gas four times. 1300g of cyclohexane, 500g of isoprene, and 0.75g of THF were added sequentially to the polymerization reactor. After heating to 50°C, 76 mmol of n-butyllithium was added to initiate the reaction, which lasted 66 min to form the IR segment. Then, 180g of the SB / (S→B) copolymer and 40g of the composite functionalized macromolecular long-chain monomer were mixed with 1800g of cyclohexane and stirred for 56 min until completely dissolved. This mixture was then added to the polymerization reactor along with 2.0g of THF and reacted for 96 min. Finally, 20.0g of [unspecified substance] was added to the polymerization reactor. 1,3-Butadiene was end-capped and reacted for 26 minutes until no free monomers were present. The solution was then wet-coagulated and dried to obtain a composite functionalized macromolecular long-branched linker d (Mn is 7300, Mw / Mn is 7.58).

[0142] (2) Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber for oil fields:

[0143] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 4.

[0144] Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber (NBR) for oilfields: Other conditions are the same as in Example 4, except that no composite functionalized macromolecular long-branched grafting agent is added during the preparation of NBR for oilfields. Instead, composite functionalized macromolecular long-branched grafting agent d is added, with an addition amount of 11.0 g. Specifically: First, 200 g of HNBR rubber is dissolved in chlorobenzene solution to prepare a glue solution with a mass fraction of 8.1%. Then, the glue solution is added to a 10 L stainless steel reactor with a jacket, and nitrogen is introduced to replace it 4 times. Then, 11.0 g of composite functionalized macromolecular long-branched grafting agent d is added to the reactor, stirred and mixed, and heated. When the reactor temperature reaches 86 °C, a mixture of 0.23 g of BPO and 160 g of chlorobenzene is added. After reacting for 9.2 hours, the mixture is flocculated with anhydrous ethanol, washed, and dried in a 70 °C oven to constant weight to obtain compression-resistant and cold-resistant hydrogenated NBR for oilfields (grafting rate 2.4%). Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0145] Comparative Example 5

[0146] (1) Preparation of composite functionalized macromolecular long-branched linking agents:

[0147] Preparation of a composite functionalized macromolecular long-chain monomer: Same as in Example 5.

[0148] Preparation of b SB / (S→B) copolymer: Same as in Example 5.

[0149] Preparation of the composite functionalized macromolecular long-branched linker: Other conditions were the same as in Example 5, except that the amount of isoprene added during the preparation of the composite functionalized macromolecular long-branched linker was 300g. Specifically, in a 10L stainless steel polymerization reactor with a jacket, the system was purged with argon gas five times. Then, 1400g of cyclohexane, 300g of isoprene, and 0.85g of THF were added sequentially to the reactor. After heating to 50°C, 72mmol of n-butyllithium was added to initiate the reaction. Within 68 minutes, the temperature gradually increased from 50°C to 80°C, forming IR segments with a broad vinyl distribution. Then, 190g of the SB / (S→B) copolymer and 45g of the composite functionalized macromolecular long-chain monomer were mixed with 1900g of cyclohexane and stirred for 58 minutes until completely dissolved. Finally, 2.3g of... THF was added to the polymerization reactor and reacted for 98 min. Finally, 22.0 g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was continued for 28 min until no free monomers were present. The solution was then wet-coagulated and dried to obtain the composite functionalized macromolecular long-branched linker e (Mn is 5300, Mw / Mn is 9.13).

[0150] (2) Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber for oil fields:

[0151] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 5.

[0152] Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber (NBR) for oilfields: Other conditions are the same as in Example 5, except that no composite functionalized macromolecular long-branched grafting agent is added during the preparation of NBR for oilfields. Instead, composite functionalized macromolecular long-branched grafting agent e is added, with an addition amount of 13.0g. Specifically: First, 200g of HNBR rubber is dissolved in chlorobenzene solution to prepare a glue solution with a mass fraction of 8.5%. 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, 13.0g of composite functionalized macromolecular long-branched grafting agent e is added to the reactor, stirred and mixed, and heated. When the reactor temperature reaches 88°C, a mixture of 0.26g of BPO and 180g of chlorobenzene is added. After reacting for 9.6 hours, the mixture is flocculated with anhydrous ethanol, washed, and dried in a 70°C oven to constant weight to obtain compression-resistant and cold-resistant hydrogenated NBR for oilfields (grafting rate 2.5%). Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0153] Comparative Example 6

[0154] (1) Preparation of composite functionalized macromolecular long-branched linking agents:

[0155] Preparation of a composite functionalized macromolecular long-chain monomer: Same as in Example 6.

[0156] b. Preparation of SB / (S→B) copolymer: The difference from Example 6 is that the preparation of the SB / (S→B) copolymer is omitted.

[0157] Preparation of the composite functionalized macromolecular long-branched linker: Other conditions were the same as in Example 6, except that the SB / (S→B) copolymer was not added during the preparation of the composite functionalized macromolecular long-branched linker. Instead, 200g of the small molecule monomer 1,3-butadiene was added, i.e., 300g of isoprene was added. Specifically, in a 10L stainless steel polymerization reactor with a jacket, the system was purged with argon gas five times. 1500g of cyclohexane, 500g of isoprene, and 1.0g of THF were added sequentially to the polymerization reactor. After heating to 50°C, 70mmol of n-butyllithium was added to initiate the reaction. Within 70min, the temperature gradually increased from 50°C to 80°C, forming IR segments with a broad vinyl distribution. Then, 200g of 1,3-butadiene and 50g of the composite functionalized macromolecular long-chain monomer were mixed with 2000g of cyclohexane and stirred for 60min until completely dissolved. Finally, 2.5g of... THF was added to the polymerization reactor and reacted for 100 min. Finally, 25.0 g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was continued for 30 min until no free monomers were present. The solution was then wet-coagulated and dried to obtain the composite functionalized macromolecular long-branched linker f (Mn is 7600, Mw / Mn is 8.26).

[0158] (2) Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber for oil fields:

[0159] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 6.

[0160] Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber (NBR) for oilfields: Other conditions are the same as in Example 6, except that no composite functionalized macromolecular long-branched grafting agent is added during the preparation of NBR for oilfields. Instead, composite functionalized macromolecular long-branched grafting agent f is added, with an addition amount of 16.0 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. Then, 16.0 g of composite functionalized macromolecular long-branched grafting agent f is added to the reactor, stirred and mixed, and heated. When the reactor temperature reaches 90 °C, a mixture of 0.30 g of BPO and 200 g of chlorobenzene is added. After reacting for 10.0 h, the mixture is flocculated with anhydrous ethanol, washed, and dried in a 70 °C oven to constant weight to obtain compression-resistant and cold-resistant hydrogenated NBR for oilfields (grafting rate 2.9%). Sampling and Analysis: Standard samples were prepared, and their performance was tested (see Table 1).

[0161] Table 1. Properties of compression-resistant and cold-resistant hydrogenated nitrile rubber for oilfield applications.

[0162]

[0163] As shown in Table 1, the oilfield-grade compression-resistant and cold-resistant hydrogenated nitrile rubber of the present invention has small compression set and low glass transition temperature, and is suitable for oil well operations with compression set ≤16% and operating temperature of -71℃.

[0164] 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 compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber for oilfield use, characterized in that, Includes the following steps: (1) Preparation of composite functionalized macromolecular long-branched linking agents: Preparation of a composite functionalized macromolecular long-chain monomer: Argon gas was introduced into the polymerization reactor to replace the system. Solvent, dihydromyrcenol, N-(4-hydroxybutyl)acrylamide, and structure modifier were added to the polymerization reactor in sequence. The temperature was raised, and initiator 1 was added to the polymerization reactor for reaction. Finally, 1,3-butadiene was added to the polymerization reactor for end-capping. The reaction continued until no free monomers were present. The gel solution was wet coagulated and dried to obtain the composite functionalized macromolecular long-chain monomer. b. Preparation of 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. Preparation of the composite functionalized macromolecular long-branched linker: In a polymerization reactor, argon gas is introduced to purge the system. Solvent, isoprene, and the first structure modifier are added sequentially to the polymerization reactor. The temperature is raised, and initiator 1 is added. The reaction is a temperature-switching polymerization, in which the temperature is gradually increased from 50℃ to 80℃ within 60-70 minutes to form IR segments with a wide vinyl distribution. Then, the SB / (S→B) copolymer and the composite functionalized macromolecular long-chain monomer are mixed with the solution and stirred until completely dissolved. Then, the mixture is added to the polymerization reactor along with the second structure modifier 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 then wet-coagulated and dried to obtain the composite functionalized macromolecular long-branched linker. (2) Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber for oil fields: 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 system is pressurized, heated, and reacted. The system is then cooled, condensed, and dried to obtain HNBR rubber. Preparation of compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber for 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. Then, a composite functionalized macromolecular long-branched linking agent is added to the reaction vessel, stirred and mixed, heated, and a mixture of initiator 2 and chlorobenzene is added. The reaction proceeds, followed by flocculation, washing, and drying to obtain compression-resistant and cold-resistant hydrogenated nitrile butadiene rubber for oilfields. The composite functionalized macromolecular long-branched linker has the following structure: Wherein, IR is a homopolymer segment of isoprene with a broad vinyl distribution; SB is a random segment of styrene and 1,3-butadiene; (S→B) is a gradient segment of styrene and butadiene; B is a terminated 1,3-butadiene; n is the number of repeating units, and n is a positive integer ≥ 1; the number average molecular weight (Mn) of the composite functionalized macromolecular long-branched linker is 6000-8000, and the molecular weight distribution (Mw / Mn) is 9.13-10.

86.

2. 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.

3. 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 0.15 parts based on 100 parts of HNBR rubber.

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

5. 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.

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

7. The preparation method according to claim 1, characterized in that, In step (1)a, the mass ratio of the solvent, dihydromyrcenol, N-(4-hydroxybutyl)acrylamide, structure modifier, and 1,3-butadiene is 200-300:60-70:30-40:0.1-0.3:2-5.

8. The preparation method according to claim 1, characterized in that, In step (1)b, the mass ratio of the solvent, structure modifier, 1,3-butadiene, and styrene is 300-400:0.1-0.4:100:30-40.

9. The preparation method according to claim 1, characterized in that, In step (1)c, the mass ratio of the solvent, isoprene, primary structure modifier, SB / (S→B) copolymer and composite functionalized macromolecular long-chain monomer, solution, secondary structure modifier, and 1,3-butadiene is 200-300:100:0.05-0.2:30-40:5-10:300-400:0.2-0.5:2-5.

10. 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.

11. 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%.

12. The preparation method according to claim 1, characterized in that, In step (2)b, the mass ratio of the HNBR rubber, the composite functionalized macromolecular long-branched linker, and the chlorobenzene is 100:2-8:50-100.

13. The preparation method according to claim 1, characterized in that, In step (2)b, the grafting rate of the oilfield-use compression-resistant and cold-resistant hydrogenated nitrile rubber is 2.2% to 3.1%.

14. An oilfield-grade, compression-resistant, cold-resistant hydrogenated nitrile butadiene rubber obtained by the preparation method according to any one of claims 1-13.

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