Cold-resistant and compression-resistant hydrogenated nitrile rubber for oil field and preparation method thereof

Abstract

This invention discloses a method for preparing cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oilfield use. The preparation method includes: (1) preparation of a composite functionalized macromolecular long-branched linker, and (2) preparation of the oilfield-grade cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber. The composite functionalized macromolecular long-branched linker has the following structure: wherein IR is a homopolymer segment of isoprene with a wide vinyl distribution; B is a capped 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 7.23-8.17. The preparation method of the oilfield-grade cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber of this invention has the characteristics of being green and environmentally friendly, having a high efficiency of modification, low modifier dosage, readily available raw materials, and being suitable for industrial production.

Description

Technical Field

[0001] This invention belongs to the field of rubber technology, specifically relating to a cold-resistant and compression-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, some of which are also attached to ester side groups. The ester side groups are generated by a ring-opening reaction between C6-C24 acid anhydrides 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 acid anhydrides under the action of a catalyst to introduce ester groups, thereby obtaining a special hydrogenated nitrile butadiene rubber containing epoxy groups and ester groups. CN 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 cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber (NBR) for oilfield use, with a compression set ≤21% and a glass transition temperature (Tg) <-70℃, meeting the requirements for use in the range of -70℃ to -73℃. 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, isoprene and the composite functionalized macromolecular long-chain monomer are polymerized at variable temperature to prepare a composite functionalized macromolecular long-branched grafting agent with a broad vinyl distribution and free radical reactivity. Finally, the composite functionalized macromolecular long-branched grafting agent is grafted onto the main chain of hydrogenated nitrile butadiene rubber to prepare the cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oilfield use. This method not only solves the problem of easy crystallization in hydrogenated nitrile butadiene rubber (NBR), but also improves its viscoelasticity, resulting in excellent low-temperature resistance and deformation resistance. It achieves a balance between these two properties, making it highly suitable for oil well operations at temperatures as low as -70°C.

[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 cold-resistant and compression-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] Preparation of composite functionalized macromolecular long-branched linking agent: 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 70℃ within 60-70 minutes to form IR segments with a wide vinyl distribution. Then, the composite functionalized macromolecular long-chain monomer and the solution are mixed and stirred until completely dissolved. Then, it 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 wet-coagulated and dried to obtain the composite functionalized macromolecular long-branched linking agent.

[0013] (2) Preparation of cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oil fields:

[0014] Preparation of hydrogenated nitrile butadiene rubber (HNBR): First, nitrile butadiene rubber is dissolved in chlorobenzene solution to prepare a rubber solution. Then, the rubber solution is added to a reaction vessel and an inert gas is introduced to remove the air in the reaction vessel. Next, hydrogen is used to remove the inert gas in the reaction vessel. Then, under nitrogen protection, a xylene solution of Grubbs I catalyst is added, pressurized, heated, and reacted. The system is then cooled, condensed, and vacuum dried to obtain HNBR rubber.

[0015] Preparation of cold-resistant and compression-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 cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oilfields.

[0016] The composite functionalized macromolecular long-branched linker has the following structure:

[0017]

[0018] Wherein, IR is a homopolymer segment of isoprene with a broad vinyl distribution; B is a capped 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 7.23-8.17.

[0019] 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.

[0020] 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. The amount added is 0.01 to 0.2 parts, preferably 0.08 to 0.15 parts, based on 100 parts by weight of HNBR rubber.

[0021] The nitrile rubber of the present invention is copolymerized from 1,3-butadiene and acrylonitrile through emulsion polymerization, wherein the acrylonitrile content of the nitrile rubber is 20wt% to 42wt%, preferably 22wt% to 35wt%.

[0022] 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).

[0023] 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.

[0024] 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.

[0025] In step (1)a of the present invention, the temperature is raised to 50-60°C.

[0026] In step (1)a of the present invention, the reaction time after adding initiator 1 is 70-80 min; the reaction time after adding 1,3-butadiene is 30-40 min.

[0027] In step (1)b of the present invention, the mass ratio of the solvent, isoprene, primary structure modifier, composite functionalized macromolecular long-chain monomer, solution, secondary structure modifier, and 1,3-butadiene is 300-400:100:0.1-0.5:5-10:100-200:0.1-0.3:2-5.

[0028] In step (1)b of the present invention, the stirring and dissolving time is 30-40 min; the reaction time when it is added to the polymerization reactor is 70-80 min; and the reaction time when 1,3-butadiene is added for end-capping is 20-30 min.

[0029] 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.

[0030] In step (2)a of the present invention, the mass fraction of nitrile rubber in the adhesive solution is 3% to 6%.

[0031] 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%.

[0032] 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.

[0033] In step (2)a of the present invention, the degree of hydrogenation of the HNBR rubber is less than 90%.

[0034] 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 100:3-5:50-100.

[0035] In step (2)b of the present invention, the mass fraction of HNBR rubber in the adhesive solution is 6% to 9%.

[0036] In step (2)b of the present invention, the heating temperature is 70-80°C; the reaction time is 8.0-10.0 hr.

[0037] In step (2)b of the present invention, the grafting rate of the cold-resistant and compression-resistant hydrogenated nitrile rubber for oil fields is 2.6% to 3.4%.

[0038] 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.

[0039] The reaction vessel described in this invention can be a loop reactor or a batch reactor, preferably a batch reactor.

[0040] 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.

[0041] The present invention also provides a cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oil fields prepared by the above-mentioned method.

[0042] Compared with the prior art, the present invention has at least the following advantages and beneficial effects:

[0043] (1) 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 greatly reduce the glass transition temperature (Tg) of HNBR. It can prepare cold-resistant and compression-resistant hydrogenated nitrile rubber for oil fields with a glass transition temperature Tg < -70℃, which is suitable for oil well operations under low temperature conditions of -70℃.

[0044] (2) The composite functionalized macromolecular long-branched grafting agent prepared in this invention is mainly prepared by anionic polymerization of the reactive monomer isoprene and the composite functionalized macromolecular long-chain monomer through temperature-variable polymerization. This grafting agent utilizes the "structural effect" of the widely distributed unsaturated "carbon-carbon" double bonds and the branched structure of the long branches to significantly improve the viscoelasticity of HNBR and reduce the compression set of HNBR. It can be used to prepare cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oil fields with a compression set of ≤21%.

[0045] (3) The composite functionalized macromolecular long-branched grafting agent prepared by the present invention can significantly reduce the glass transition temperature (Tg) of HNBR and improve the compression set resistance of HNBR with a low addition amount, and achieve a good "synergistic effect" in achieving a balance between cold resistance and compression set resistance.

[0046] (4) The preparation method of the oilfield cold-resistant and compression-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. Attached Figure Description

[0047] Figure 1 The image shows the infrared spectrum of the composite functionalized macromolecular long-branched linker in Example 1. Detailed Implementation

[0048] 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.

[0049] (1) Source of raw materials:

[0050]

[0051] (2) Analysis and testing methods:

[0052] 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:

[0053]

[0054] 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).

[0055] 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 .

[0056] 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:

[0057] Degree of hydrogenation (HD%) = 1 - Degree of unsaturation (U)

[0058] Infrared spectroscopy analysis of samples: Functional group analysis of samples before and after modification with nano-silica was performed using an infrared spectrometer from Bruke Spectroscopy Instruments, Germany. Samples were dried in a vacuum oven at 100℃, pressed into pellets using potassium bromide, and wavenumbers were collected in the range of 400-4000 cm⁻¹. -1 .

[0059] 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.

[0060] Compression set: The method specified in standard GB / T 7759.1-2015 shall be followed.

[0061] Example 1

[0062] (1) Preparation of composite functionalized macromolecular long-branched linking agents:

[0063] 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.

[0064] Preparation of composite functionalized macromolecular long-branched linker: In a 10L stainless steel polymerization reactor with a jacket, the system was purged three times with argon gas. 1500g of cyclohexane, 500g of isoprene, and 0.5g of THF were added sequentially to the polymerization reactor. The temperature was raised to 50℃, and 93mmol of n-butyllithium was added to initiate the reaction. Within 60 minutes, the temperature was gradually increased from 50℃ to 70℃, forming IR segments with a broad vinyl distribution. Then, 25g of composite functionalized macromolecular long-chain monomer and 500g of cyclohexane were mixed and stirred for 30 minutes until completely dissolved. This mixture, along with 0.5g of THF, was added to the polymerization reactor and reacted for 70 minutes. Finally, 10g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was continued for 20 minutes until no free monomers remained. The resulting solution was wet-coagulated and dried to obtain the composite functionalized macromolecular long-branched linker (Mn = 6000, Mw / Mn = 7.23).

[0065] (2) Preparation of cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oil fields:

[0066] 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%).

[0067] Preparation of cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber (HNBR) 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 jacketed stainless steel reactor, 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 70℃, a mixture of 0.16g of BPO and 100g of 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 cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oilfield use (grafting rate 2.6%). Sampling and analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0068] Example 2

[0069] (1) Preparation of composite functionalized macromolecular long-branched linking agents:

[0070] 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.

[0071] Preparation of composite functionalized macromolecular long-branched linker: In a 10L stainless steel polymerization reactor with a jacket, the system was purged three times with argon gas. 1600g of cyclohexane, 500g of isoprene, and 1.0g of THF were added sequentially to the polymerization reactor. The temperature was raised to 50℃, and 87mmol of n-butyllithium was added to initiate the reaction. Within 62 minutes, the temperature gradually increased from 50℃ to 70℃, forming IR segments with a broad vinyl distribution. Then, 30g of composite functionalized macromolecular long-chain monomer and 600g of cyclohexane were mixed and stirred for 32 minutes until completely dissolved. This mixture was then added to the polymerization reactor along with 0.7g of THF and reacted for 72 minutes. Finally, 13g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was continued for 22 minutes until no free monomers remained. The resulting solution was wet-coagulated and dried to obtain the composite functionalized macromolecular long-branched linker (Mn = 6500, Mw / Mn = 7.39).

[0072] (2) Preparation of cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oil fields:

[0073] 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 32 minutes. Then, under nitrogen protection, 0.03g 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 105℃. After reacting for 9.5 hours, the system was cooled, condensed, and vacuum dried to obtain HNBR rubber (hydrogenation degree HD = 85.7%).

[0074] Preparation of cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber (HNBR) for oilfield use: First, 200g of HNBR rubber was dissolved in a chlorobenzene solution to prepare a 6.6% (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, 7.0g of a composite functionalized macromolecular long-branched grafting agent was added to the reactor, stirred, and heated. When the reactor temperature reached 72℃, a mixture of 0.19g of BPO and 120g of 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 cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oilfield use (grafting rate 2.8%). Sampling and analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0075] Example 3

[0076] (1) Preparation of composite functionalized macromolecular long-branched linking agents:

[0077] 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.

[0078] Preparation of composite functionalized macromolecular long-branched linker: In a 10L stainless steel polymerization reactor with a jacket, the system was purged with argon gas four times. 1700g of cyclohexane, 500g of isoprene, and 1.5g of THF were added sequentially to the polymerization reactor. The temperature was raised to 50℃, and 82mmol of n-butyllithium was added to initiate the reaction. Within 64 minutes, the temperature gradually increased from 50℃ to 70℃, forming IR segments with a broad vinyl distribution. Then, 35g of composite functionalized macromolecular long-chain monomer and 700g of cyclohexane were mixed and stirred for 34 minutes until completely dissolved. This mixture was then added to the polymerization reactor along with 0.9g of THF and reacted for 74 minutes. Finally, 15g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was continued for 24 minutes until no free monomers remained. The resulting solution was wet-coagulated and dried to obtain the composite functionalized macromolecular long-branched linker (Mn = 7000, Mw / Mn = 7.68).

[0079] (2) Preparation of cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oil fields:

[0080] Preparation of hydrogenated nitrile butadiene rubber (HNBR): First, 100g of nitrile butadiene rubber 2907 was dissolved in chlorobenzene solution to prepare a 4% (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 34 min. Then, under nitrogen protection, 0.05g of xylene solution containing Grubbs I catalyst (w / w, 7% (w / w)) was added. The hydrogen pressure in the reactor was increased to 12MPa, and the temperature was raised to 110℃. After reacting for 10 h, the system was cooled, condensed, and vacuum dried to obtain HNBR rubber (hydrogenation degree HD = 86.2%).

[0081] Preparation of cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber (HNBR) for oilfield use: First, 200g of HNBR rubber was dissolved in a chlorobenzene solution to prepare a 7.4% (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 four times. Next, 8.0g of a composite functionalized macromolecular long-branched grafting agent was added to the reactor, stirred, and heated. When the reactor temperature reached 74℃, a mixture of 0.22g of BPO and 140g of 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 cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oilfield use (grafting rate 3.0%). Sampling and analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0082] Example 4

[0083] (1) Preparation of composite functionalized macromolecular long-branched linking agents:

[0084] 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.

[0085] Preparation of composite functionalized macromolecular long-branched linker: In a 10L stainless steel polymerization reactor with a jacket, the system was purged with argon gas four times. 1800g of cyclohexane, 500g of isoprene, and 2.0g of THF were added sequentially to the polymerization reactor. The temperature was raised to 50℃, and 79mmol of n-butyllithium was added to initiate the reaction. Within 66 minutes, the temperature gradually increased from 50℃ to 70℃, forming IR segments with a broad vinyl distribution. Then, 40g of composite functionalized macromolecular long-chain monomer and 800g of cyclohexane were mixed and stirred for 36 minutes until completely dissolved. This mixture was then added to the polymerization reactor along with 1.0g of THF and reacted for 76 minutes. Finally, 19g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was continued for 26 minutes until no free monomers remained. The resulting solution was wet-coagulated and dried to obtain the composite functionalized macromolecular long-branched linker (Mn = 7400, Mw / Mn = 7.86).

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

[0087] 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%).

[0088] Preparation of cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber (HNBR) for oilfield use: First, 200g of HNBR rubber was dissolved in a chlorobenzene solution to prepare a rubber solution with a mass fraction of 8.0%. 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, 9.0g of a composite functionalized macromolecular long-branched grafting agent was added to the reactor, stirred, and heated. When the reactor temperature reached 76℃, a mixture of 0.24g of BPO and 160g of chlorobenzene was added. After reacting for 9.3 hours, the mixture was flocculated with anhydrous ethanol, washed, and dried in a 70℃ oven to constant weight to obtain cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oilfield use (grafting rate 3.1%). Sampling and analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0089] Example 5

[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 five times. 1400g of cyclohexane, 340g of dihydromyrcenol, 160g of N-(4-hydroxybutyl)acrylamide, and 1.3g of THF were added to the polymerization reactor in sequence. The temperature was raised to 58℃, and then 137mmol of n-butyllithium was added to the polymerization reactor and reacted for 78min. Finally, 23g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was continued for 38min until no free monomers were present. The solution was then wet-coagulated and dried to obtain composite functionalized macromolecular long-chain monomers.

[0092] Preparation of composite functionalized macromolecular long-branched linker: In a 10L stainless steel polymerization reactor with a jacket, the system was purged with argon gas five times. 1900g of cyclohexane, 500g of isoprene, and 2.2g of THF were added to the polymerization reactor sequentially. The temperature was raised to 50℃, and 74mmol of n-butyllithium was added to initiate the reaction. Within 68min, the temperature gradually increased from 50℃ to 70℃, forming IR segments with a broad vinyl distribution. Then, 45g of composite functionalized macromolecular long-chain monomer and 900g of cyclohexane were mixed and stirred for 38min until completely dissolved. Then, 1.3g of THF was added to the polymerization reactor and reacted for 78min. Finally, 22g of 1,3-butadiene was added to the polymerization reactor for end-capping, and the reaction was carried out for 28min until no free monomers were present. The solution was wet-coagulated and dried to obtain the composite functionalized macromolecular long-branched linker (Mn = 7800, Mw / Mn = 7.98).

[0093] (2) Preparation of cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oil fields:

[0094] 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%).

[0095] Preparation of cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber (HNBR) for oilfield use: First, 200g of HNBR rubber was dissolved in a chlorobenzene solution to prepare a rubber solution with a mass fraction of 8.4%. 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, 9.5g of a composite functionalized macromolecular long-branched grafting agent was added to the reactor, stirred, and heated. When the reactor temperature reached 78℃, a mixture of 0.27g of BPO and 180g of chlorobenzene was added. After reacting for 9.7 hours, the mixture was flocculated with anhydrous ethanol, washed, and dried in a 70℃ oven to constant weight to obtain cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oilfield use (grafting rate 3.3%). Sampling and analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0096] Example 6

[0097] (1) Preparation of composite functionalized macromolecular long-branched linking agents:

[0098] 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.

[0099] Preparation of composite functionalized macromolecular long-branched linker: In a jacketed 10L stainless steel polymerization reactor, the system was purged five times with argon gas. 200g cyclohexane, 500g isoprene, and 2.5g THF were added sequentially to the reactor. The temperature was raised to 50℃, and 71mmol n-butyllithium was added to initiate the reaction. Within 70min, the temperature was gradually increased from 50℃ to 70℃, forming IR segments with a broad vinyl distribution. Then, 50g of the composite functionalized macromolecular long-chain monomer and 1000g cyclohexane were mixed and stirred for 40min until completely dissolved. This mixture was then added to the polymerization reactor along with 1.5g THF and reacted for 80min. Finally, 25g 1,3-butadiene was added to the reactor for end-capping, and the reaction was continued for 30min until no free monomers remained. The resulting solution was wet-coagulated and dried to obtain the composite functionalized macromolecular long-branched linker (Mn = 8000, Mw / Mn = 8.17).

[0100] (2) Preparation of cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oil fields:

[0101] Preparation of hydrogenated nitrile butadiene rubber (HNBR): First, 100g of nitrile butadiene rubber 2907 was dissolved in chlorobenzene solution to prepare a 6.0% (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 40 minutes. Then, under nitrogen protection, 0.1g of xylene solution containing Grubbs I catalyst (w / w, 10% (w / w)) was added. The hydrogen pressure in the reactor was increased to 14MPa, and the temperature was raised to 120℃. After reacting for 11 hours, the system was cooled, condensed, and vacuum dried to obtain HNBR rubber (hydrogenation degree HD = 89.4%).

[0102] Preparation of cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber (HNBR) for oilfield use: First, 200g of HNBR rubber was dissolved in a chlorobenzene solution to prepare a 9.0% (by mass) adhesive solution. Then, the adhesive solution was added to a 10L stainless steel reactor with a jacket, and nitrogen was introduced to purge five times. Next, 10.0g 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 0.30g of BPO and 200g of 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 cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oilfield use (grafting rate 3.4%). Sampling and analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0103] Comparative Example 1

[0104] (1) Preparation of composite functionalized macromolecular long-branched linking agents:

[0105] Preparation of composite functionalized macromolecular long-chain monomer a: Other conditions are the same as in Example 1, except that N-(4-hydroxybutyl)acrylamide is not added during the preparation of the composite functionalized macromolecular long-chain monomer. Instead, 200g of acrylamide is added. Specifically, in a 10L stainless steel polymerization reactor with a jacket, the system is purged with argon gas three times. 1000g of cyclohexane, 300g of dihydromyrcene alcohol, 200g of acrylamide, and 0.5g of THF are added to the polymerization reactor in sequence. The temperature is raised to 50°C, and then 150mmol of n-butyllithium is added to the polymerization reactor and reacted for 70min. Finally, 10g of 1,3-butadiene is added to the polymerization reactor for end-capping, and the reaction is continued for 30min until no free monomers are present. The solution is then wet-coagulated and dried to obtain composite functionalized macromolecular long-chain monomer a.

[0106] Preparation of composite functionalized macromolecular long-chain branching agent: Other conditions are the same as in Example 1, except that no composite functionalized macromolecular long-chain monomer is added during the preparation of the composite functionalized macromolecular long-chain branching agent. Instead, composite functionalized macromolecular long-chain monomer a is added in an amount of 25g. That is, in a 10L stainless steel polymerization reactor with a jacket, the system is purged with argon gas three times. 1500g of cyclohexane, 500g of isoprene, and 0.5g of THF are added to the polymerization reactor in sequence. The temperature is raised to 50°C, and 93mmol of n-butyllithium is added to start the reaction. Within 60min, the temperature is gradually raised from 50°C to 70°C to form IR segments with a broad vinyl distribution. Then, 25g of composite functionalized macromolecular long-chain monomer a and 500g of cyclohexane are mixed and stirred for 30min until completely dissolved. Then, it is added to the polymerization reactor along with 0.5g of THF and reacted for 70min. Finally, 10g of [unspecified substance] is 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 a (Mn is 5900, Mw / Mn is 6.91).

[0107] (2) Preparation of cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oil fields:

[0108] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 1.

[0109] Preparation of cold-resistant and compression-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 the cold-resistant and compression-resistant hydrogenated NBR for oilfields. Instead, composite functionalized macromolecular long-branched grafting agent a is added, with an addition amount of 6.0g. That is: 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 replace it three times. Then, 6.0g of composite functionalized macromolecular long-branched grafting agent a is added to the reactor, stirred and mixed, and heated. When the reactor temperature reaches 70°C, a mixture of 0.16g 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 cold-resistant and compression-resistant hydrogenated NBR for oilfields (grafting rate 2.3%). Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0110] Comparative Example 2

[0111] (1) Preparation of composite functionalized macromolecular long-branched linking agents:

[0112] Preparation of composite functionalized macromolecular long-chain monomers: Other conditions are the same as in Example 2, except that dihydromyrcenol is not added during the preparation of composite functionalized macromolecular long-chain monomers, but allyl alcohol is added in an amount of 310g. That is, in a 10L stainless steel polymerization reactor with a jacket, the system is purged with argon gas three times, and 1100g cyclohexane, 310g allyl alcohol, 190g N-(4-hydroxybutyl)acrylamide, and 0.7g THF are added to the polymerization reactor in sequence. The temperature is raised to 52°C, and then 147mmol n-butyllithium is added to the polymerization reactor and reacted for 72min. Finally, 13g 1,3-butadiene is added to the polymerization reactor for end-capping, and the reaction is carried out for 32min until no free monomers are present. The solution is wet coagulated and dried to obtain composite functionalized macromolecular long-chain monomer b.

[0113] Preparation of composite functionalized macromolecular long-chain branching agent b: Other conditions are the same as in Example 2, except that composite functionalized macromolecular long-chain monomer b is not added during the preparation of the composite functionalized macromolecular long-chain branching agent. Instead, composite functionalized macromolecular long-chain monomer b is added in an amount of 30g. That is, in a 10L stainless steel polymerization reactor with a jacket, the system is purged with argon gas three times. 1600g of cyclohexane, 500g of isoprene, and 1.0g of THF are added to the polymerization reactor in sequence. The temperature is raised to 50°C, and 87mmol of n-butyllithium is added to start the reaction. Within 62min, the temperature is gradually raised from 50°C to 70°C to form IR segments with a wide vinyl distribution. Then, 30g of composite functionalized macromolecular long-chain monomer b and 600g of cyclohexane are mixed and stirred for 32min until completely dissolved. Then, it is added to the polymerization reactor along with 0.7g of THF and reacted for 72min. Finally, 13g of THF is added to the polymerization reactor. 1,3-Butadiene was end-capped and reacted 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 b (Mn is 5700, Mw / Mn is 5.75).

[0114] (2) Preparation of cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oil fields:

[0115] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 2.

[0116] Preparation of cold-resistant and compression-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 7.0g. Specifically: First, 200g of HNBR rubber is dissolved in chlorobenzene solution to prepare a 6.6% 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, 7.0g of composite functionalized macromolecular long-branched grafting agent b is added to the reactor, stirred and mixed, and heated. When the reactor temperature reaches 72°C, a mixture of 0.19g 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 cold-resistant and compression-resistant hydrogenated NBR for oilfields (grafting rate 2.6%). Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0117] Comparative Example 3

[0118] (1) Preparation of composite functionalized macromolecular long-branched linking agents:

[0119] Preparation of composite functionalized macromolecular long-chain monomers: Other conditions are the same as in Example 3, except that N-(4-hydroxybutyl)acrylamide is not added during the preparation of composite functionalized macromolecular long-chain monomers. That is: in a 10L stainless steel polymerization reactor with a jacket, the system is purged with argon gas four times, and 1200g of cyclohexane, 320g of dihydromyrcene alcohol, and 0.9g of THF are added to the polymerization reactor in sequence. The temperature is raised to 54°C, and then 143mmol of n-butyllithium is added to the polymerization reactor and reacted for 74min. Finally, 17g of 1,3-butadiene is added to the polymerization reactor for end-capping, and the reaction is carried out for 34min until no free monomers are present. The solution is wet-coagulated and dried to obtain composite functionalized macromolecular long-chain monomer c.

[0120] Preparation of the composite functionalized macromolecular long-chain branching agent: Other conditions are the same as in Example 3, except that the composite functionalized macromolecular long-chain monomer is not added during the preparation of the composite functionalized macromolecular long-chain branching agent. Instead, 35g of composite functionalized macromolecular long-chain monomer c is added. That is, in a 10L stainless steel polymerization reactor with a jacket, the system is purged with argon gas four times. 1700g of cyclohexane, 500g of isoprene, and 1.5g of THF are added to the polymerization reactor in sequence. The temperature is raised to 50°C, and 82mmol of n-butyllithium is added to start the reaction. Within 64min, the temperature is gradually raised from 50°C to 70°C to form IR segments with a wide vinyl distribution. Then, 35g of composite functionalized macromolecular long-chain monomer c and 700g of cyclohexane are mixed and stirred for 34min until completely dissolved. Then, it is added to the polymerization reactor along with 0.9g of THF and reacted for 74min. Finally, 15g of [unspecified substance] is added to the polymerization reactor. 1,3-Butadiene was end-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 5200, Mw / Mn is 5.23).

[0121] (2) Preparation of cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oil fields:

[0122] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 3.

[0123] Preparation of cold-resistant and compression-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 linker is added during the preparation of the cold-resistant and compression-resistant hydrogenated NBR for oilfields. Instead, composite functionalized macromolecular long-branched linker c is added, with an addition amount of 8.0g. Specifically: First, 200g of HNBR rubber is dissolved in chlorobenzene solution to prepare a 7.4% 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, 8.0g of composite functionalized macromolecular long-branched linker c is added to the reactor, stirred and mixed, and heated. When the reactor temperature reaches 74°C, a mixture of 0.22g 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 cold-resistant and compression-resistant hydrogenated NBR for oilfields (grafting rate 2.3%). Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0124] Comparative Example 4

[0125] (1) Preparation of composite functionalized macromolecular long-branched linking agents:

[0126] Preparation of composite functionalized macromolecular long-chain monomers: Other conditions are the same as in Example 4, except that the amount of N-(4-hydroxybutyl)acrylamide added in the preparation of composite functionalized macromolecular long-chain monomers is 100g. That is, in a 10L stainless steel polymerization reactor with a jacket, the system is purged with argon gas 4 times, and 1300g cyclohexane, 330g dihydromyrcene alcohol, 100g N-(4-hydroxybutyl)acrylamide, and 1.1g THF are added to the polymerization reactor in sequence. The temperature is raised to 56°C, and then 140mmol n-butyllithium is added to the polymerization reactor and reacted for 76min. Finally, 20g 1,3-butadiene is added to the polymerization reactor for end-capping, and the reaction is carried out for 36min until no free monomers are present. The solution is wet coagulated and dried to obtain composite functionalized macromolecular long-chain monomers d.

[0127] Preparation of the composite functionalized macromolecular long-chain branching agent: Other conditions are the same as in Example 4, except that the composite functionalized macromolecular long-chain monomer is not added during the preparation of the composite functionalized macromolecular long-chain branching agent. Instead, 40g of composite functionalized macromolecular long-chain monomer d is added. That is, in a 10L stainless steel polymerization reactor with a jacket, the system is purged with argon gas four times. 1800g of cyclohexane, 500g of isoprene, and 2.0g of THF are added to the polymerization reactor in sequence. The temperature is raised to 50°C, and 79mmol of n-butyllithium is added to start the reaction. Within 66min, the temperature is gradually raised from 50°C to 70°C to form IR segments with a wide vinyl distribution. Then, 40g of composite functionalized macromolecular long-chain monomer d and 800g of cyclohexane are mixed and stirred for 36min until completely dissolved. Then, it is added to the polymerization reactor along with 1.0g of THF and reacted for 76min. Finally, 19g of cyclohexane is added to the polymerization reactor. 1,3-Butadiene was 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 5700, Mw / Mn is 7.12).

[0128] (2) Preparation of cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oil fields:

[0129] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 4.

[0130] Preparation of cold-resistant and compression-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 the cold-resistant and compression-resistant hydrogenated NBR for oilfields. Instead, composite functionalized macromolecular long-branched grafting agent d is added, with an addition amount of 9.0 g. That is: First, 200 g of HNBR rubber is dissolved in chlorobenzene solution to prepare a glue solution with a mass fraction of 8.0%. 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, 9.0 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 76 °C, a mixture of 0.24 g of BPO and 160 g of chlorobenzene is added. After reacting for 9.3 hours, the mixture is flocculated with anhydrous ethanol, washed, and dried in a 70 °C oven to constant weight to obtain cold-resistant and compression-resistant hydrogenated NBR for oilfields (grafting rate 3.1%). Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0131] Comparative Example 5

[0132] (1) Preparation of composite functionalized macromolecular long-branched linking agents:

[0133] Other conditions are the same as in Example 5, except that no long-chain monomer of the composite functionalized macromolecular branching agent is added during the preparation of the composite functionalized macromolecular branching agent. Instead, a small molecule reactive monomer, N-(4-hydroxybutyl)acrylamide, is added in an amount of 45g. Specifically, in a 10L stainless steel polymerization reactor with a jacket, the system is purged with argon gas five times. 1900g of cyclohexane, 500g of isoprene, and 2.2g of THF are added to the polymerization reactor sequentially. The temperature is raised to 50°C, and 74mmol of n-butyllithium is added to initiate the reaction. Within 68 minutes, the temperature is gradually increased from 50°C to 70°C to form IR segments with a broad vinyl distribution. Then, 45g of N-(4-hydroxybutyl)acrylamide and 900g of cyclohexane are mixed and stirred for 38 minutes until completely dissolved. Then, it is added to the polymerization reactor along with 1.3g of THF and reacted for 78 minutes. Finally, 22g of N-(4-hydroxybutyl)acrylamide is added to the polymerization reactor. 1,3-Butadiene was 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 e (Mn is 4900, Mw / Mn is 4.63).

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

[0135] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 5.

[0136] Preparation of cold-resistant and compression-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 the cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oilfields. Instead, composite functionalized macromolecular long-branched grafting agent e is added, with an addition amount of 9.5g. Specifically: First, 200g of HNBR rubber is dissolved in chlorobenzene solution to prepare a glue solution with a mass fraction of 8.4%. Then, the glue solution is added to a 10L stainless steel reactor with a jacket, and nitrogen is introduced to purge it 5 times. Then, 9.5g of composite functionalized macromolecular long-branched grafting agent e is added to the reactor, stirred and mixed, and heated. When the reactor temperature reaches 78°C, a mixture of 0.27g of BPO and 180g of chlorobenzene is added. After reacting for 9.7 hours, the mixture is flocculated with anhydrous ethanol, washed, and dried in a 70°C oven to constant weight to obtain cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oilfields (grafting rate 2.4%). Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0137] Comparative Example 6

[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 6.

[0140] b. Preparation of composite functionalized macromolecular long-branched linking agents: Same as in Example 6.

[0141] (2) Preparation of cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oil fields:

[0142] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 6.

[0143] Preparation of cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber (NBR) for oilfields: Other conditions were the same as in Example 6, except that the amount of BPO added in the preparation process was 0.005 g. Specifically: First, 200 g of HNBR rubber was dissolved in a chlorobenzene solution to prepare a 9.0% (w / w) adhesive solution. Then, the adhesive solution was added to a 10 L stainless steel reactor with a jacket, and nitrogen was introduced five times for purging. Next, 10.0 g of a composite functionalized macromolecular long-branched grafting agent was added to the reactor, stirred, and heated. When the reactor temperature reached 80 °C, a mixture of 0.005 g of BPO and 200 g of chlorobenzene was added. After reacting for 10.0 h, the mixture was flocculated with anhydrous ethanol, washed, and dried in a 70 °C oven to constant weight to obtain cold-resistant and compression-resistant hydrogenated NBR for oilfields (grafting rate 1.6%). Sampling and analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0144] Table 1. Properties of Cold-Resistant and Compression-Resistant Hydrogenated Nitrile Rubber for Oilfield Use

[0145]

[0146] As shown in Table 1, the cold-resistant and compression-resistant hydrogenated nitrile rubber for oil fields of the present invention has a low glass transition temperature and small compression set, making it suitable for oil well operations under low-temperature conditions with a working temperature of -70℃.

[0147] Figure 1 The image shows the infrared spectrum of the composite functionalized macromolecular long-branched linker in Example 1. From... Figure 1 From this, we can know that the wave number is 3600–35100 cm⁻¹. -1 The asymmetric condensation vibration double absorption peak appears at 2950–2800 cm⁻¹. -1 An absorption peak for the secondary condensation vibration of methyl (CH3) appears at a wavenumber of 1680–1500 cm⁻¹. -1 An absorption peak for the condensation vibration of a carbon-carbon double bond appears at a wavelength of 1630–1520 cm⁻¹. -1 The presence of a condensation vibration absorption peak of the amide group indicates that the composite functionalized macromolecular long-branched linker prepared from dihydromyrcenol, N-(4-hydroxybutyl)acrylamide, and isoprene contains structures such as amide groups, hydroxyl groups, methyl groups, and carbon-carbon double bonds.

[0148] 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 cold-resistant and compression-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: In a polymerization reactor, argon gas is introduced to replace the system. Solvent, dihydromyrcenol, N-(4-hydroxybutyl)acrylamide, and structure modifier are added sequentially to the polymerization reactor. The temperature is raised, and then 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 gel solution is wet-coagulated and dried to obtain the composite functionalized macromolecular long-chain monomer. 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. Preparation of the composite functionalized macromolecular long-branched linker: In the 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, with the temperature gradually increased from 50℃ to 70℃ over 60-70 minutes to form IR segments with a broad vinyl distribution. Then, the composite functionalized macromolecular long-chain monomer is mixed with the solution and stirred until completely dissolved. Finally, it is added to the polymerization reactor along with the second structure modifier. The reaction proceeds as follows: 1,3-butadiene is added to the polymerization reactor for end-capping, and the reaction continues until no free monomers are present. The resulting solution is then wet-coagulated and dried to obtain a composite functionalized macromolecular long-chain branching agent. The mass ratio of the solvent, isoprene, primary structure modifier, composite functionalized macromolecular long-chain monomer, solution, secondary structure modifier, and 1,3-butadiene is 300~400:100:0.1~0.5:5~10:100~200:0.1~0.3:2~5. (2) Preparation of cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oil fields: Preparation of hydrogenated nitrile butadiene rubber (HNBR): First, nitrile butadiene rubber is dissolved in chlorobenzene solution to prepare a rubber solution. Then, the rubber solution is added to a reaction vessel, and an inert gas is introduced to remove air from the reaction vessel. Next, hydrogen is used to purge the inert gas from the reaction vessel. Under nitrogen protection, a xylene solution of Grubbs I catalyst is added, pressurized, heated, and reacted. The system is then cooled, condensed, and vacuum dried to obtain HNBR rubber. The mass ratio of nitrile butadiene rubber to Grubbs I catalyst is 100:0.02~0.

1. Preparation of cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber (NBR) 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. A composite functionalized macromolecular long-branched grafting agent is then added to the reaction vessel. The mixture is stirred, heated, and a mixture of initiator 2 and chlorobenzene is added. The reaction proceeds, followed by flocculation, washing, and drying to obtain cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oilfields. The grafting rate of the oilfield-grade cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber is 2.6%–3.4%. The mass ratio of HNBR rubber, composite functionalized macromolecular long-branched grafting agent, and chlorobenzene is 100:3~5:50~100. The composite functionalized macromolecular long-branched linker has the following structure: Wherein, IR is a homopolymer segment of isoprene with a wide vinyl distribution; B is a capped 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 7.23~8.

17.

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 0.01 to 0.2 parts based on 100 parts by weight 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 through 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 (2)a, the degree of hydrogenation of the HNBR rubber is less than 90%.

8. A cold-resistant and compression-resistant hydrogenated nitrile butadiene rubber for oil fields, obtained by the preparation method according to any one of claims 1-7.

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