Deformation-resistant low-temperature-grade hydrogenated nitrile rubber for oil field and preparation method thereof

Abstract

The invention discloses a deformation-resistant and low-temperature-grade hydrogenated nitrile rubber for an oil field and a preparation method thereof.The preparation method comprises the steps of (1) preparation of a macromolecular long-branch-chain grafting agent and (2) preparation of the deformation-resistant and low-temperature-grade hydrogenated nitrile rubber for the oil field, the macromolecular long-branch-chain grafting agent has the following structure: # imgabs0 #, PS is a styrene homopolymer segment, BR is 1, 2-propylene glycol, and the macromolecular long-branch-chain grafting agent has the following structure; r is a C6-C12 straight-chain alkyl group, a 1, 3-butadiene homopolymer segment, and R is a C6-C12 straight-chain alkyl group; m and n are repetitive unit numbers, n is a positive integer greater than or equal to 1, and m is a positive integer greater than or equal to 1; the number-average molecular weight (Mn) of the macromolecular long-chain grafting agent is 6000 to 7000. The preparation method of the deformation-resistant and low-temperature-grade hydrogenated nitrile rubber for the oil field has the characteristics of environment friendliness, efficient and stable modification effect, low modifier dosage, commercially available and easily available raw materials, suitability for industrial production and the like.

Description

Technical Field

[0001] This invention belongs to the field of rubber technology, specifically relating to a deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber modified with a macromolecular long-chain branching agent for oilfield use, and its preparation method. Background Art

[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 glycation (Tg). Consequently, HNBR products exhibit poor low-temperature 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 low-temperature resistance from 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 low-temperature resistant 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 5℃ compression set ≥0.16. CN 105754164A discloses a low-temperature resistant rubber material. Although this material has improved low-temperature 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 low-temperature performance 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 low-temperature resistance of hydrogenated nitrile butadiene rubber can be improved to some extent by adding small-molecule modifiers, copolymerization, and blending, these methods still have certain 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 of existing technologies, this invention provides a method for preparing a deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber (NBR) for oilfield use. The NBR exhibits a tear strength ≥42 KN / m, compression set ≤26%, and glass transition temperature (Tg) <-57℃, meeting the requirements for use within the temperature range of -57℃ to 59℃. This invention first uses anionic polymerization to prepare a block copolymer through distribution synthesis. Then, it reacts with a long-chain α-olefin monomer and ethylene under the action of a nickel-based complexing catalyst to prepare a macromolecular long-chain grafting agent with free radical reactivity. Finally, the macromolecular long-chain grafting agent is grafted onto the main chain of the hydrogenated NBR to prepare the deformation-resistant, low-temperature grade hydrogenated NBR for oilfield use. This method not only solves the problem of easy crystallization in hydrogenated NBR but also avoids the decrease in mechanical properties caused by reduced crystallinity. This results in hydrogenated NBR exhibiting excellent low-temperature performance while maintaining sufficient mechanical properties and deformation resistance, achieving a balance between low-temperature performance, mechanical properties, and deformation resistance. It is ideal for oil well operations with a working temperature of -57℃, a tear strength of ≥42KN / m, and a compression set of ≤26%.

[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 deformation-resistant, low-temperature-grade hydrogenated nitrile butadiene rubber for oilfield use, the method comprising the following steps:

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

[0011] Preparation of a–BR-PS- copolymer: Argon gas was introduced into the polymerization reactor to replace the system. Solvent, 1,3-butadiene, structure modifier, and initiator 1 were added to the polymerization reactor in sequence. The temperature was raised and the reaction was carried out to form BR segments. Then styrene and structure modifier were added to the polymerization reactor in sequence. The temperature was raised and the reaction was carried out until no free monomers were present. The glue solution was wet coagulated and dried to obtain a–BR-PS-block copolymer.

[0012] b. Preparation of macromolecular long-branched linking agent: Inert gas was introduced into the reaction vessel for purging, solvent was added, the temperature was raised, and alkylaluminoxane co-catalyst was added under stirring. Stirring was continued under inert gas protection. Then, the –BR-PS-block copolymer and solution were mixed and stirred to dissolve until completely dissolved. Then, it was added to the reaction vessel together with long-chain α-olefin and nickel-based complexing catalyst. Ethylene was introduced at this time, and the reaction was carried out. After the reaction was completed, the macromolecular long-branched linking agent was obtained by centrifugation and drying.

[0013] (2) Preparation of deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfield use:

[0014] 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, 0.02-0.1 parts of xylene solution containing Grubbs I catalyst are added under nitrogen protection. The mixture is pressurized, heated, and reacted. The system is then cooled, condensed, and dried to obtain HNBR rubber.

[0015] b. Preparation of deformation-resistant, low-temperature grade 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. A macromolecular long-branched linking agent is then 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 deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfields.

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

[0017]

[0018] Wherein, PS represents the styrene homopolymer segment, BR represents the 1,3-butadiene homopolymer segment, and R represents C6 to C6. 12 The linear alkyl group; m and n are the number of repeating units, n is a positive integer ≥ 1, and m is a positive integer ≥ 1; the number average molecular weight (Mn) of the macromolecular long-linked branching agent is 6000 to 7000.

[0019] The long-chain α-olefin described in this invention is a C6-C6 α-olefin. 12 The straight-chain olefin may be selected from one of 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, and 1-dodecene, with 1-octene being preferred.

[0020] The nickel-based complexing catalyst of the present invention is selected from one of (1-naphthyl)[8-(diphenylphosphino)quinoline]nickel, trans-phenylbromo(di(triphenylphosphine))nickel and 2,5-dicarboxypyrrole dibromide, preferably trans-phenylbromo(di(triphenylphosphine))nickel.

[0021] The alkylaluminoxane cocatalyst described in this invention is selected from one of methylaluminoxane (MAO) and ethylaluminoxane (EAO), with methylaluminoxane being preferred.

[0022] 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.

[0023] The initiator 2 described in this invention is an organic peroxide selected from one of diacetyl peroxide, diisobutyryl peroxide, cumene hydroperoxide, dicumene peroxide (DCP), and dibenzoyl peroxide, preferably dicumene peroxide (DCP). The amount added is 0.0 to 0.2 parts, preferably 0.1 to 0.15 parts, based on 100 parts by weight of HNBR rubber.

[0024] 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%.

[0025] 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).

[0026] 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.

[0027] In step (1)a of the present invention, during the formation of the BR segment, the mass ratio of solvent, 1,3-butadiene, and structure modifier is 400-500:100:0.5-1.0, the temperature is raised to 50-60°C, and the reaction time is 60-70 min.

[0028] In step (1)a of the present invention, based on 100 parts by mass of 1,3-butadiene, the amount of styrene added during the formation of the –BR-PS-block copolymer is 40 to 60 parts, the amount of the structure modifier added is 1.0 to 1.5 parts, the temperature is raised to 70 to 80°C, and the reaction time is 80 to 90 min.

[0029] In step (1)b of the present invention, the mass ratio of the solvent, alkylaluminoxane co-catalyst, BR-PS-block copolymer, solvent, long-chain α-olefin, and nickel-based complex catalyst is 300-400: 20-30: 2.0-4.0: 100-200: 8-15: 1.

[0030] In step (1)b of the present invention, the temperature is raised to 80-90°C; the stirring speed is 700-800 rpm; the stirring time is 20-30 min; the stirring and dissolving time is 40-60 min; the reaction pressure is 15-20 MPa and the reaction time is 6.0-7.0 hr.

[0031] 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.

[0032] In step (2)a of the present invention, the mass fraction of nitrile rubber in the adhesive solution is 3% to 6%.

[0033] 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%.

[0034] 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.

[0035] In step (2)a of the present invention, the degree of hydrogenation of the HNBR rubber is less than 90%.

[0036] In step (2)b of the present invention, the mass ratio of the HNBR rubber, the macromolecular long-branched linker, and the chlorobenzene is 100:2-4:100-200.

[0037] In step (2)b of the present invention, the mass fraction of HNBR rubber in the adhesive solution is 6% to 9%.

[0038] In step (2)b of the present invention, the heating temperature is 80-90°C; the reaction time is 9.0-10.0 hr.

[0039] In step (2)b of the present invention, the grafting rate of the deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfield use is 1.8% to 3.2%.

[0040] 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.

[0041] The reaction vessel described in this invention can be a loop reactor or a batch reactor, preferably a batch reactor.

[0042] 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.

[0043] The present invention also provides a deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfield use obtained by the above preparation method.

[0044] Compared with the prior art, the present invention has at least the following advantages and beneficial effects:

[0045] (1) The macromolecular long-branched grafting agent prepared in this invention is used to prepare a –BR-PS-block copolymer by anionic polymerization through distribution synthesis. Then, it is combined with a long-chain α-olefin through coordination polymerization to form a macromolecular long-branched chain. The chain is activated by ethylene to make it free radical reactive and can be grafted onto hydrogenated nitrile butadiene rubber. A long-chain branched structure containing benzene rings and unsaturated double bonds is formed on the main chain structure of hydrogenated nitrile butadiene rubber. This structure organically combines the long-branched structure, benzene rings and unsaturated double bond structure on a macromolecular chain. While reducing the crystallinity of HNBR and improving the viscoelasticity, it also avoids the decline of the mechanical properties of HNBR. It achieves a good “synergistic effect” in achieving a balance between low temperature resistance, deformation resistance and tear resistance. It can prepare a deformation-resistant and low-temperature grade hydrogenated nitrile butadiene rubber for oilfield use with a tear strength ≥42KN / m, compression set ≤26% and glass transition temperature Tg<-57℃.

[0046] (2) The deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber prepared by the present invention, under the condition of ensuring a certain degree of hydrogenation, makes full use of the "accumulation effect" and "group effect" of benzene ring and unsaturated double bond. It can greatly reduce the glass transition temperature (Tg) of HNBR with a low addition amount, while also significantly improving the compression set resistance and tear strength of HNBR. It is suitable for oil well operations under low temperature conditions of -57℃.

[0047] (3) The method for preparing deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oil fields of the present invention has the characteristics of being green and environmentally friendly, having a high efficiency and stable modification effect, low modifier dosage, readily available raw materials, and being suitable for industrial production. 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] 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.

[0059] Compression set: The method specified in standard GB / T 7759.1-2015 shall be followed.

[0060] Tear strength: The method specified in standard GB / T 529-2009 shall be applied.

[0061] Example 1

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

[0063] Preparation of α–BR-PS- copolymer: In a jacketed 10L stainless steel polymerization reactor, the system was purged three times with argon gas. 2000g cyclohexane, 500g 1,3-butadiene, 2.5g THF, and 192mmol n-butyllithium were added to the polymerization reactor in sequence. The temperature was raised to 50℃ and the reaction was carried out for 60min to form BR segments. Then, 200g styrene and 5.0g THF were added to the polymerization reactor in sequence, and the temperature was raised to 70℃ and the reaction was carried out for 80min until no free monomers were present. The solution was wet-coagulated and dried to obtain the α–BR-PS- copolymer.

[0064] b. Preparation of macromolecular long-branched linking agents: First, nitrogen gas was purged three times in a 10L high-pressure reactor. Then, 3000g of cyclohexane was added, and the temperature was raised to 80℃. Then, 200g of methylaluminoxane co-catalyst was gradually added dropwise under uniform stirring at 700rpm. Stirring continued for 20min under nitrogen protection. Finally, 20g of...

[0065] –BR-PS- copolymer and 1000g cyclohexane were mixed and stirred for 40min to dissolve. Then, 80g 1-octene and 10g trans-bromophenyl (di(triphenylphosphine))nickel main catalyst were added to a high-pressure reactor. Ethylene was introduced and the pressure was maintained at 15MPa for 6.0hr. After the reaction was completed, the mixture was centrifuged, dried and the macromolecular long-branched linker (number average molecular weight Mn was 6000) was obtained.

[0066] (2) Preparation of deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfield use:

[0067] 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%).

[0068] Preparation of deformation-resistant, low-temperature grade 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) adhesive solution. Then, the adhesive solution was added to a 10L jacketed stainless steel reactor, and nitrogen was introduced three times for purging. Next, 4.0g of a macromolecular long-branched grafting agent was added to the reactor, stirred, and heated. When the reactor temperature reached 80℃, a mixture of 0.20g of DCP and 200g 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 deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfield use (grafting rate 1.8%). Sampling and analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0069] Example 2

[0070] (1) Preparation of macromolecular long-branched linking agents:

[0071] Preparation of α–BR-PS- copolymer: In a 10L stainless steel polymerization reactor with a jacket, the system was purged three times with argon gas. 2100g cyclohexane, 500g 1,3-butadiene, 3.0g THF, and 203mmol n-butyllithium were added to the polymerization reactor in sequence. The temperature was raised to 52℃ and the reaction was carried out for 62min to form BR segments. Then, 220g styrene and 5.5g THF were added to the polymerization reactor in sequence, and the temperature was raised to 72℃ and the reaction was carried out for 82min until no free monomers were present. The solution was wet-coagulated and dried to obtain the α–BR-PS- copolymer.

[0072] b. Preparation of macromolecular long-branched linking agents: First, nitrogen gas was purged three times in a 10L high-pressure reactor. Then, 3200g of cyclohexane was added, and the temperature was raised to 82℃. Then, 220g of methylaluminoxane co-catalyst was gradually added dropwise under uniform stirring at 720rpm. Stirring continued for 22min under nitrogen protection. Finally, 25g of...

[0073] –BR-PS- copolymer and 1200g cyclohexane were mixed and stirred for 45min to dissolve. Then, 90g 1-octene and 10g trans-bromophenyl (di(triphenylphosphine))nickel main catalyst were added to a high-pressure reactor. Ethylene was introduced and the pressure was maintained at 16MPa for 6.2hr. After the reaction was completed, the mixture was centrifuged, dried and the macromolecular long-branched linker (number average molecular weight Mn was 6100) was obtained.

[0074] (2) Preparation of deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfield use:

[0075] 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%).

[0076] Preparation of deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber (HNBR) 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 jacketed stainless steel reactor, and nitrogen was introduced three times for purging. Next, 4.5g of a macromolecular long-branched grafting agent was added to the reactor, stirred, and heated. When the reactor temperature reached 82℃, a mixture of 0.22g of DCP and 260g 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 deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfield use (grafting rate 2.1%). Sampling and analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0077] Example 3

[0078] (1) Preparation of macromolecular long-branched linking agents:

[0079] Preparation of α–BR-PS- copolymer: In a jacketed 10L stainless steel polymerization reactor, the system was purged with argon gas four times. 2200g cyclohexane, 500g 1,3-butadiene, 3.5g THF, and 211mmol n-butyllithium were added to the polymerization reactor sequentially. The temperature was raised to 54℃ and the reaction was carried out for 65min to form BR segments. Then, 240g styrene and 6.0g THF were added to the polymerization reactor sequentially, and the temperature was raised to 74℃ and the reaction was carried out for 84min until no free monomers were present. The solution was then wet-coagulated and dried to obtain the α–BR-PS- copolymer.

[0080] b. Preparation of macromolecular long-branched linking agents: First, nitrogen gas was purged four times in a 10L high-pressure reactor. Then, 3400g of cyclohexane was added, and the temperature was raised to 84℃. Then, 240g of methylaluminoxane co-catalyst was gradually added dropwise under uniform stirring at 740rpm. Stirring continued for 24min under nitrogen protection. Finally, 30g of...

[0081] –BR-PS- copolymer and 1500g cyclohexane were mixed and stirred for 50min to dissolve. Then, 110g 1-octene and 10g trans-bromophenyl (di(triphenylphosphine))nickel main catalyst were added to a high-pressure reactor. Ethylene was introduced and the pressure was maintained at 17MPa for 6.4hr. After the reaction was completed, the mixture was centrifuged, dried and the macromolecular long-branched linker (number average molecular weight Mn was 6300) was obtained.

[0082] (2) Preparation of deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfield use:

[0083] 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%).

[0084] Preparation of deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber (HNBR) for oilfield use: First, 200g of HNBR rubber was dissolved in a chlorobenzene solution to prepare a 7.0% (by mass) rubber solution. Then, the solution was added to a 10L jacketed stainless steel reactor, and nitrogen was introduced four times for purging. Next, 5.0g of a macromolecular long-branched grafting agent was added to the reactor, stirred, and heated. When the reactor temperature reached 84℃, a mixture of 0.24g DCP and 280g chlorobenzene was added. After reacting for 9.4 hours, the mixture was flocculated with anhydrous ethanol, washed, and dried in a 70℃ oven to constant weight to obtain deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfield use (grafting rate 2.4%). Sampling and analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0085] Example 4

[0086] (1) Preparation of macromolecular long-branched linking agents:

[0087] Preparation of α–BR-PS- copolymer: In a jacketed 10L stainless steel polymerization reactor, the system was purged with argon gas four times. 2300g cyclohexane, 500g 1,3-butadiene, 4.0g THF, and 219mmol n-butyllithium were added to the polymerization reactor sequentially. The temperature was raised to 56℃ and the reaction was carried out for 67min to form BR segments. Then, 260g styrene and 6.5g THF were added to the polymerization reactor sequentially, and the temperature was raised to 76℃ and the reaction was carried out for 85min until no free monomers were present. The solution was wet-coagulated and dried to obtain the α–BR-PS- copolymer.

[0088] b. Preparation of macromolecular long-branched linking agents: First, nitrogen gas was purged four times in a 10L high-pressure reactor. Then, 3600g of cyclohexane was added, and the temperature was raised to 85℃. Then, 260g of methylaluminoxane co-catalyst was gradually added dropwise under uniform stirring at 760rpm. Stirring continued for 26min under nitrogen protection. Finally, 34g of...

[0089] –BR-PS- copolymer and 1700g cyclohexane were mixed and stirred for 53min to dissolve. Then, 120g 1-octene and 10g trans-bromophenyl (di(triphenylphosphine))nickel main catalyst were added to a high-pressure reactor. Ethylene was introduced and the pressure was maintained at 18MPa for 6.6hr. After the reaction was completed, the mixture was centrifuged, dried and the macromolecular long-branched linker (number average molecular weight Mn was 6600) was obtained.

[0090] (2) Preparation of deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfield use:

[0091] 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%).

[0092] Preparation of deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber (HNBR) for oilfield use: First, 200g of HNBR rubber was dissolved in a chlorobenzene solution to prepare a 7.5% (by mass) rubber solution. Then, the solution was added to a 10L jacketed stainless steel reactor, and nitrogen was introduced four times for purging. Next, 6.0g of a macromolecular long-branched grafting agent was added to the reactor, stirred, and heated. When the reactor temperature reached 86℃, a mixture of 0.26g of DCP and 320g 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 deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfield use (grafting rate 2.7%). Sampling and analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0093] Example 5

[0094] (1) Preparation of macromolecular long-branched linking agents:

[0095] Preparation of α–BR-PS- copolymer: In a jacketed 10L stainless steel polymerization reactor, the system was purged with argon five times. 2400g cyclohexane, 500g 1,3-butadiene, 4.5g THF, and 224mmol n-butyllithium were added sequentially to the polymerization reactor. The temperature was raised to 58℃ and the reaction was carried out for 69min to form BR segments. Then, 280g styrene and 6.8g THF were added sequentially to the polymerization reactor, and the temperature was raised to 78℃ and the reaction was carried out for 87min until no free monomers were present. The solution was then wet-coagulated and dried to obtain the α–BR-PS- copolymer.

[0096] b. Preparation of macromolecular long-branched linking agents: First, nitrogen gas was purged four times in a 10L high-pressure reactor. Then, 3800g of cyclohexane was added, and the temperature was raised to 87℃. Then, 280g of methylaluminoxane co-catalyst was gradually added dropwise under uniform stirring at 780rpm. Stirring continued for 28min under nitrogen protection. Finally, 36g of...

[0097] –BR-PS- copolymer and 1700g cyclohexane were mixed and stirred for 57 min to dissolve. Then, 140g 1-octene and 10g trans-bromophenyl (di(triphenylphosphine))nickel main catalyst were added to a high-pressure reactor. Ethylene was introduced and the pressure was maintained at 19MPa for 6.8 hours. After the reaction was completed, the polymer was centrifuged, dried and the macromolecular long-branched linker (number average molecular weight Mn was 6800) was obtained.

[0098] (2) Preparation of deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfield use:

[0099] Preparation of hydrogenated nitrile butadiene rubber (HNBR): First, 100g of nitrile butadiene rubber 2907 was dissolved in chlorobenzene solution to prepare a 5.0% (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 38 min. Then, under nitrogen protection, 0.09g of xylene solution containing Grubbs I catalyst (w / w) was added. The hydrogen pressure in the reactor was increased to 13MPa, and the temperature was raised to 117℃. After reacting for 11 hours, the system was cooled, condensed, and vacuum dried to obtain HNBR rubber (hydrogenation degree HD = 88.3%).

[0100] Preparation of deformation-resistant, low-temperature grade 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 solution was added to a 10L stainless steel reactor with a jacket, and nitrogen was introduced to purge the solution five times. Next, 7.0g of a macromolecular long-branched grafting agent was added to the reactor, stirred, and heated. When the reactor temperature reached 89℃, a mixture of 0.29g of DCP and 360g of chlorobenzene was added. After reacting for 9.8 hours, the mixture was flocculated with anhydrous ethanol, washed, and dried in a 70℃ oven to constant weight to obtain deformation-resistant, low-temperature grade 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.

[0101] Example 6

[0102] (1) Preparation of macromolecular long-branched linking agents:

[0103] Preparation of α–BR-PS- copolymer: In a 10L stainless steel polymerization reactor with a jacket, the system was purged with argon gas 5 times. Then, 2500g of cyclohexane, 500g of 1,3-butadiene, 5.0g of THF, and 245mmol of n-butyllithium were added to the polymerization reactor in sequence. The temperature was raised to 60℃ and the reaction was carried out for 70min to form BR segments. Then, 300g of styrene and 7.5g of THF were added to the polymerization reactor in sequence. The temperature was raised to 80℃ and the reaction was carried out for 90min until no free monomers were present. The solution was wet coagulated and dried to obtain α–BR-PS- copolymer.

[0104] b. Preparation of macromolecular long-branched linking agents: First, nitrogen gas was purged five times in a 10L high-pressure reactor. 4000g of cyclohexane was added, and the temperature was raised to 90℃. Then, 300g of methylaluminoxane co-catalyst was gradually added dropwise under uniform stirring at 800rpm. Stirring continued for 30min under nitrogen protection. Subsequently, 40g of...

[0105] –BR-PS- copolymer and 2000g cyclohexane were mixed and stirred for 60min to dissolve. Then, 150g 1-hexene and 10g trans-bromophenyl (di(triphenylphosphine))nickel main catalyst were added to a high-pressure reactor. Ethylene was introduced and the pressure was maintained at 20MPa for 7.0hr. After the reaction was completed, the mixture was centrifuged, dried and the macromolecular long-branched linker (number average molecular weight Mn was 7000) was obtained.

[0106] (2) Preparation of deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfield use:

[0107] 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%).

[0108] Preparation of deformation-resistant, low-temperature grade 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) rubber solution. Then, the solution was added to a 10L jacketed stainless steel reactor, and nitrogen was introduced to purge five times. Next, 8.0g of a 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 400g 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 deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfield use (grafting rate 3.2%). Sampling and analysis: Standard samples were prepared, and the tested properties are shown in Table 1.

[0109] Comparative Example 1

[0110] (1) Preparation of macromolecular long-branched linking agents:

[0111] Preparation of a–BR-PS copolymer: Same as in Example 1.

[0112] Preparation of macromolecular long-branched linking agent: Other conditions are the same as in Example 1, except that the amount of –BR-PS- copolymer added in the preparation of macromolecular long-branched linking agent is 10g. That is: first, nitrogen gas is purged three times in a 10L high-pressure reactor, 3000g of cyclohexane is added, the temperature is raised to 80℃, and 200g of methylaluminoxane co-catalyst is added dropwise under uniform stirring at 700rpm. Stirring is continued for 20min under nitrogen protection. Then, 10g of –BR-PS- copolymer and 1000g of cyclohexane are mixed and stirred to dissolve for 40min. Then, 80g of 1-octene and 10g of trans-bromophenyl (di(triphenylphosphine))nickel main catalyst are added to the high-pressure reactor. Ethylene is introduced and the pressure is maintained at 15MPa for 6.0hr. After the reaction is completed, the macromolecular long-branched linking agent a (number average molecular weight Mn is 5200) is obtained by centrifugation and drying.

[0113] (2) Preparation of deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfield use:

[0114] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 1.

[0115] b. Preparation of deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfields: Other conditions are the same as in Example 1, except that no long-branched macromolecular linker is added during the preparation of the deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfields. Instead, long-branched macromolecular linker a is added, with an addition amount of 4.0g. 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, 4.0g of long-branched macromolecular linker a is added to the reactor, stirred and mixed, and heated. When the reactor temperature reaches 80°C, a mixture of 0.20g of DCP and 200g 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 deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfields (grafting rate 1.6%). Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0116] Comparative Example 2

[0117] (1) Preparation of macromolecular long-branched linking agents:

[0118] Preparation of α–BR-PS copolymer: Other conditions are the same as in Example 2, except that...

[0119] The –BR-PS- copolymer is prepared without the addition of styrene. Specifically, in a jacketed 10L stainless steel polymerization reactor, the system is purged three times with argon gas. Then, 2100g of cyclohexane, 500g of 1,3-butadiene, 3.0g of THF, and 203mmol of n-butyllithium are added to the polymerization reactor in sequence. The temperature is raised to 52℃ and the reaction is carried out for 62min until no free monomers are present. The solution is then wet-coagulated and dried to obtain the –BR- homopolymer.

[0120] Preparation of macromolecular long-branched linking agent b: Other conditions are the same as in Example 2, except that –BR-PS- copolymer is not added during the preparation of macromolecular long-branched linking agent, but –BR- homopolymer is added, with an addition amount of 25g. That is: first, nitrogen is purged three times in a 10L high-pressure reactor, 3200g of cyclohexane is added, and after heating to 82°C, 220g of methylaluminoxane co-catalyst is gradually added dropwise under uniform stirring at 720rpm. Stirring is continued for 22min under nitrogen protection. Then, 25g of –BR- copolymer and 1200g of cyclohexane are mixed and stirred to dissolve for 45min. Then, 90g of 1-octene and 10g of trans-bromophenyl (di(triphenylphosphine))nickel main catalyst are added to the high-pressure reactor, ethylene is introduced, and the pressure is maintained at 16MPa for 6.2hr. After the reaction is completed, the macromolecular long-branched linking agent b (number average molecular weight Mn is 5500) is obtained by centrifugation and drying.

[0121] (2) Preparation of deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfield use:

[0122] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 2.

[0123] Preparation of deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfields: Other conditions are the same as in Example 2, except that no macromolecular long-branched grafting agent is added during the preparation of the deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfields. Instead, macromolecular long-branched grafting agent b is added, with an addition amount of 4.5g. That is: 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, 4.5g of 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 0.22g of DCP and 260g 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 deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfields (grafting rate 1.9%). Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0124] Comparative Example 3

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

[0126] Preparation of α–BR-PS copolymer: Other conditions are the same as in Example 3, except that...

[0127] The BR-PS- copolymer is prepared without the addition of 1,3-butadiene. Specifically, in a jacketed 10L stainless steel polymerization reactor, the system is purged with argon gas four times. Then, 2200g of cyclohexane, 240g of styrene, and 6.0g of THF are added to the polymerization reactor in sequence. The temperature is raised to 74℃, and the reaction is carried out for 84 minutes until no free monomers are present. The solution is then wet-coagulated and dried to obtain the BR-PS- homopolymer.

[0128] b. Preparation of macromolecular long-branched linking agent: Other conditions are the same as in Example 3, except that instead of adding the –BR-PS- copolymer, 30g of -PS- homopolymer is added during the preparation of the macromolecular long-branched linking agent. Specifically: First, nitrogen is purged into a 10L high-pressure reactor four times, then 3400g of cyclohexane is added. After heating to 84°C, 240g of methylaluminoxane co-catalyst is gradually added dropwise under uniform stirring at 740rpm. Stirring is continued for 24min under nitrogen protection. Then, 30g of -PS- homopolymer and 1500g of cyclohexane are mixed and stirred to dissolve for 50min. After that, 110g of 1-octene and 10g of trans-bromophenyl (di(triphenylphosphine))nickel main catalyst are added to the high-pressure reactor. Ethylene is introduced, and the pressure is maintained at 17MPa for 6.4hr. After the reaction is completed, the macromolecular long-branched linking agent c (number average molecular weight Mn is 3300) is obtained by centrifugation, drying, and separation.

[0129] (2) Preparation of deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfield use:

[0130] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 3.

[0131] b. Preparation of deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfields: Other conditions are the same as in Example 3, except that no long-branched macromolecular linker is added during the preparation of the deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfields. Instead, long-branched macromolecular linker c is added, with an addition amount of 5.0g. Specifically: First, 200g of HNBR rubber is dissolved in chlorobenzene solution to prepare a 7.0% (by mass) rubber solution. Then, the rubber solution is added to a 10L stainless steel reactor with a jacket, and nitrogen is introduced to purge the solution four times. Then, 5.0g of long-branched macromolecular linker c is added to the reactor, stirred and mixed, and heated. When the reactor temperature reaches 84°C, a mixture of 0.24g of DCP and 280g of chlorobenzene is added. After reacting for 9.4 hours, the mixture is flocculated with anhydrous ethanol, washed, and dried in a 70°C oven to constant weight to obtain deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfields (grafting rate 2.2%). Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0132] Comparative Example 4

[0133] (1) Preparation of macromolecular long-branched linking agents:

[0134] Preparation of α–BR-PS copolymer: Other conditions are the same as in Example 4, except that...

[0135] In the preparation of the –BR-PS- copolymer, 1,3-butadiene and styrene are not added to the polymerization in steps, but together: In a 10L stainless steel polymerization reactor with a jacket, the system is purged with argon gas four times, and 2300g cyclohexane, 500g 1,3-butadiene, 260g styrene, 4.0g THF, and 219mmol n-butyllithium are added to the polymerization reactor in sequence. The temperature is raised to 56℃ and the reaction is carried out for 67min until no free monomers are present. The glue solution is wet coagulated and dried to obtain the –SBR-block copolymer.

[0136] b. Preparation of macromolecular long-branched linking agent: Other conditions are the same as in Example 4, except that –BR-PS- copolymer is not added during the preparation of macromolecular long-branched linking agent, but –SBR-block copolymer is added, with an addition amount of 34g. That is: first, nitrogen gas is purged four times in a 10L high-pressure reactor, 3600g of cyclohexane is added, the temperature is raised to 85°C, and 260g of methylaluminoxane co-catalyst is gradually added dropwise under uniform stirring at 760rpm. Stirring is continued for 26min under nitrogen protection, and then 34g of…

[0137] –SBR-block copolymer and 1700g cyclohexane were mixed and stirred for 53min to dissolve. Then, 120g 1-octene and 10g trans-bromophenyl (di(triphenylphosphine))nickel main catalyst were added to a high-pressure reactor. Ethylene was introduced and the pressure was maintained at 18MPa for 6.6hr. After the reaction was completed, the polymer was centrifuged, dried and the macromolecular long-branched linker d (number average molecular weight Mn was 6400) was obtained.

[0138] (2) Preparation of deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfield use:

[0139] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 4.

[0140] b. Preparation of deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfields: Other conditions are the same as in Example 4, except that no long-branched macromolecular linker is added during the preparation of the deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfields. Instead, a long-branched macromolecular linker d is added, with an addition amount of 6.0g. That is: first, 200g of HNBR rubber is dissolved in chlorobenzene solution to prepare a 7.5% by mass solution. Then, the solution is added to a 10L stainless steel reactor with a jacket, and nitrogen is introduced to purge it 4 times. Then, 6.0g of long-branched macromolecular linker d is added to the reactor, stirred and mixed, and heated. When the reactor temperature reaches 86℃, a mixture of 0.26g of DCP and 320g of chlorobenzene is added. After reacting for 9.6 hours, the mixture is flocculated with anhydrous ethanol, washed, and dried in a 70℃ oven to constant weight to obtain deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfields (grafting rate 2.6%). Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0141] Comparative Example 5

[0142] (1) Preparation of macromolecular long-branched linking agents:

[0143] Other conditions were the same as in Example 5, except that styrene (36g) was added instead of the –BR-PS- copolymer during the preparation of the macromolecular long-branched linker. Specifically, nitrogen was first purged four times in a 10L high-pressure reactor, followed by the addition of 3800g of cyclohexane. After heating to 87°C, 280g of methylaluminoxane co-catalyst was gradually added dropwise under uniform stirring at 780rpm. Stirring continued for 28min under nitrogen protection. Subsequently, 36g of styrene and 1700g of cyclohexane were mixed and stirred for 57min to dissolve. Then, 140g of 1-octene and 10g of trans-bromophenyl (di(triphenylphosphine))nickel main catalyst were added to the high-pressure reactor. Ethylene was introduced, and the pressure was maintained at 19MPa for 6.8hr. After the reaction was completed, the macromolecular long-branched linker e (number average molecular weight Mn of 3800) was obtained by centrifugation, drying, and separation.

[0144] (2) Preparation of deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfield use:

[0145] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 5.

[0146] b. Preparation of deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfields: Other conditions are the same as in Example 5, except that no long-branched macromolecular linker is added during the preparation of the deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfields. Instead, long-branched macromolecular linker e is added, with an addition amount of 7.0g. Specifically: First, 200g of HNBR rubber is dissolved in chlorobenzene solution to prepare a glue solution with a mass fraction of 8.0%. 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, 7.0g of long-branched macromolecular linker e is added to the reactor, stirred and mixed, and heated. When the reactor temperature reaches 89°C, a mixture of 0.29g of DCP and 360g of chlorobenzene is added. After reacting for 9.8 hours, the mixture is flocculated with anhydrous ethanol, washed, and dried in a 70°C oven to constant weight to obtain deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfields (grafting rate 3.0%). Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0147] Comparative Example 6

[0148] (1) Preparation of macromolecular long-branched linking agents:

[0149] Preparation of a–BR-PS copolymer: Same as in Example 6.

[0150] b. Preparation of macromolecular long-branched linking agent: Other conditions are the same as in Example 6, except that 1-hexene is not added in the preparation of macromolecular long-branched linking agent, but 1-butene is added instead, with an addition amount of 150g. That is: first, nitrogen is purged into a 10L high-pressure reactor 5 times, 4000g of cyclohexane is added, and after heating to 90°C, 300g of methylaluminoxane co-catalyst is added dropwise under uniform stirring at 800rpm. Stirring is continued for 30min under nitrogen protection. Then, 40g of BR-PS- copolymer and 2000g of cyclohexane are mixed and stirred to dissolve for 60min. Then, 150g of 1-butene and 10g of trans-bromophenyl (di(triphenylphosphine))nickel main catalyst are added to the high-pressure reactor. Ethylene is introduced and the pressure is maintained at 20MPa for 7.0hr. After the reaction is completed, the macromolecular long-branched linking agent f (number average molecular weight Mn is 6500) is obtained by centrifugation, drying.

[0151] (2) Preparation of deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfield use:

[0152] Preparation of hydrogenated nitrile butadiene rubber (HNBR): Same as in Example 6.

[0153] b. Preparation of deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfields: Other conditions are the same as in Example 6, except that no long-branched macromolecular linker is added during the preparation of the deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfields. Instead, a long-branched macromolecular linker f is added, with an addition amount of 8.0 g. That is: 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 it 5 times. Then, 8.0 g of long-branched macromolecular linker 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 400 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 deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber for oilfields (grafting rate 3.2%). Sampling and analysis: Standard samples were prepared, and their performance was tested and shown in Table 1.

[0154] Table 1. Performance of hydrogenated nitrile butadiene rubber for oilfield use, including resistance to deformation and low temperatures.

[0155]

[0156]

[0157] As shown in Table 1, the deformation-resistant, low-temperature grade hydrogenated nitrile butadiene rubber of the present invention has high tear strength, low compression set and low glass transition temperature, making it suitable for oil well operations under low-temperature conditions of -57℃.

[0158] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a deformation-resistant, low-temperature grade hydrogenated nitrile rubber for oil fields, characterized in that: The steps include: (1) Preparation of macromolecular long-branched grafting agent: a. Preparation of BR-PS copolymer: In a polymerization kettle, argon is introduced to replace the system, and a solvent, 1,3-butadiene, a structure regulator, and an initiator 1 are added to the polymerization kettle in sequence, the temperature is raised, and the reaction is carried out to form a BR segment; then styrene and a structure regulator are added to the polymerization kettle in sequence, the temperature is raised, and the reaction is carried out until no free monomer exists, and the glue solution is wet-coagulated and dried to obtain a BR-PS block copolymer; b. Preparation of macromolecular long-chain branching agent: Inert gas is introduced into the reactor for replacement, solvent is added, the temperature is raised, and alkylaluminoxane co-catalyst is added under stirring. Stirring is continued under the protection of inert gas. Then, the -BR-PS-block copolymer and the solution are mixed and stirred to dissolve. After complete dissolution, the long-chain α-olefin and nickel-based complex catalyst are added to the reactor. At this time, ethylene is introduced for reaction. After the reaction is completed, the macromolecular long-branched grafting agent is obtained by centrifugal separation and drying; (2) Preparation of deformation-resistant, low-temperature grade hydrogenated nitrile rubber for oil fields: a Preparation of hydrogenated nitrile rubber (HNBR): dissolving nitrile rubber in chlorobenzene solution to prepare a rubber solution, then adding the rubber solution into a reactor and introducing an inert gas to remove the air in the reactor, then removing the inert gas in the reactor with hydrogen, adding 0.02-0.1 parts of a xylene solution of a Grubbs I catalyst under nitrogen protection, pressurizing, heating, reacting, cooling the system, condensing, and drying to obtain HNBR rubber; b. Preparation of deformation-resistant, low-temperature grade hydrogenated nitrile rubber for oil fields: HNBR rubber is dissolved in chlorobenzene solution to prepare a glue solution, and then the glue solution is added to a reactor, and an inert gas is introduced for replacement, and then a macromolecular long-branched chain grafting agent is added to the reactor, stirred and mixed, heated, and a mixed solution of initiator 2 and chlorobenzene is added, reacted, flocculated, washed, and dried to obtain a deformation-resistant, low-temperature grade hydrogenated nitrile rubber for oil fields; The macromolecular long-branched grafting agent has the following structure: Among them, PS is a styrene homopolymer segment, BR is a 1,3-butadiene homopolymer segment, and R is C6~C 12 m and n are the number of repeating units, n≥1, and m≥1; the number average molecular weight (Mn) of the macromolecular long chain grafting agent is 6000-7000.

2. The preparation method according to claim 1, characterized in that: The long-chain α-olefin is selected from one of 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene and 1-dodecene.

3. The preparation method according to claim 1, characterized in that: The nickel-based complex catalyst is selected from one of (1-naphthyl)〔8-(diphenylphosphino)quinoline〕nickel chloride, trans-phenyl(bis(triphenylphosphine))nickel bromide and 2,5-diformylpyrrole nickel dibromide.

4. The preparation method according to claim 1, characterized in that: The alkylaluminoxane cocatalyst is selected from one of methylaluminoxane (MAO) and ethylaluminoxane (EAO).

5. The preparation method according to claim 1, characterized in that: The initiator 1 is selected from one of n-butyl lithium, sec-butyl lithium, methylbutyl lithium, phenylbutyl lithium, naphthalene lithium, cyclohexyl lithium and dodecyl lithium.

6. The preparation method according to claim 1, characterized in that: The initiator 2 is selected from one of diacetyl peroxide, diisobutyryl peroxide, cumene hydroperoxide, dicumyl peroxide (DCP) and dibenzoyl peroxide, and its addition amount is 0.0-0.2 parts based on 100 parts of the mass of the HNBR rubber.

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

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

9. 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.

10. The preparation method according to claim 1, characterized in that: In step (1) a, during the formation of the BR segment, the mass ratio of the solvent, 1,3-butadiene, and the structure regulator is 400-500:100:0.5-1.

0.

11. The preparation method according to claim 1, characterized in that: In step (1) a, based on 100 parts by mass of 1,3-butadiene, during the formation of the -BR-PS-block copolymer, the amount of styrene added is 40 to 60 parts, and the amount of the structure regulator added is 1.0 to 1.5 parts.

12. The preparation method according to claim 1, characterized in that: In step (1) b, the mass ratio of the solvent, alkylaluminoxane co-catalyst, BR-PS-block copolymer, solution, long-chain α-olefin, and nickel-based complex catalyst is 300-400:20-30:2.0-4.0:100-200:8-15:

1.

13. 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.

14. The preparation method according to claim 1, characterized in that: The hydrogenation degree HD of the HNBR rubber is less than 90%.

15. The preparation method according to claim 1, characterized in that: The mass ratio of the HNBR rubber, the macromolecular long-chain branching agent and chlorobenzene is 100:2-4:100-200.

16. The preparation method according to claim 1, characterized in that: In step (2) b, the grafting rate of the deformation-resistant, low-temperature grade oilfield hydrogenated nitrile rubber is 1.8% to 3.2%.

17. A deformation-resistant, low-temperature grade hydrogenated nitrile rubber for oil fields obtained by the preparation method according to any one of claims 1 to 16.

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