Hybrid rubber of hydrogenated carboxy nitrile rubber and hydrogenated nitrile rubber and preparation method thereof

Abstract

The invention discloses a HXNBR / HNBR blend glue and a preparation method thereof. The HXNBR / HNBR blend glue is prepared from HXNBR and HNBR, meanwhile, the invention also discloses a method for preparing HXNBR by carrying out emulsion hydrogenation on carboxylic butadiene-acrylonitrile latex by adopting the ruthenium-based catalyst. And reacting for 5-11 hours under the conditions that the pressure is 5.51-7.58 MPa and the temperature is 90-120 DEG C to prepare the HXNBR with the hydrogenation degree of 90-98% and the carboxyl content of 3-7%. HXNBR and HNBR are mixed according to the mass ratio of (50-90): (10-50), and mixed rubber is prepared through first-stage mixing, second-stage mixing and vulcanization forming. The blend rubber comprises the following components in parts by weight: 60-90 parts of HXNBR, 10-40 parts of HNBR, 1-10 parts of an activating agent, 5-30 parts of a plasticizer, 20-80 parts of a reinforcing agent, 1-8 parts of a vulcanizing agent and 0.5-5 parts of an accelerant. The oil resistance coefficient of the obtained blend rubber is greater than or equal to 90%, the aging coefficient is greater than or equal to 80%, the tensile strength is greater than or equal to 22 MPa, the blend rubber is excellent in comprehensive performance, can be used for high-performance sealing products such as automobile sealing elements and oil field sealing elements, solves the problems that HXNBR is difficult to process and high in cost and HNBR is insufficient in chemical medium resistance, and has important theoretical significance and practical value.

Description

Technical Field

[0001] This invention relates to the field of rubber materials technology, specifically to a blend of hydrogenated carboxylated butadiene-acrylonitrile rubber and hydrogenated butadiene-acrylonitrile rubber and its preparation method, and also to a method for preparing hydrogenated carboxylated butadiene-acrylonitrile rubber by emulsion hydrogenation. Background Technology

[0002] Carboxylated nitrile butadiene rubber (XNBR) is a special rubber made from butadiene, acrylonitrile, and organic acids (such as acrylic acid and methacrylic acid). By introducing polar carboxyl groups into the polymer backbone, XNBR not only retains the excellent oil resistance of ordinary nitrile butadiene rubber (NBR), but also significantly improves its adhesion, abrasion resistance, and mechanical strength. However, the unsaturated carbon-carbon double bonds (C=C) in the main chain of carboxylated nitrile butadiene rubber result in poor resistance to heat and oxygen aging and ozone, limiting its application in harsh environments.

[0003] Hydrogenated carboxylated nitrile butadiene rubber (HXNBR) is a high-saturation specialty rubber prepared by selectively hydrogenating the C=C double bonds in XNBR. Due to the presence of carboxyl groups in its structure, HXNBR can form hydrogen bonds with the skeleton material or other surface groups, thus exhibiting excellent adhesive properties. It can be used in high-performance applications such as automotive timing belts, printing rollers, oil well packers, drill bit seals, explosion-proof devices, and drill pipe scrapers. However, HXNBR also has certain limitations. Its high Mooney viscosity results in poor processing flowability and relatively high production costs, restricting its large-scale application.

[0004] The preparation of HXNBR is mainly achieved through the selective hydrogenation of XNBR, with common methods including solution hydrogenation and emulsion hydrogenation. Solution hydrogenation requires a large amount of organic solvents (such as chlorobenzene and toluene), resulting in significant environmental pollution and high costs. Emulsion hydrogenation, using water as a medium, offers advantages such as mild reaction conditions, environmental friendliness, and low cost, making it a more ideal method for industrial preparation. However, existing emulsion hydrogenation methods still suffer from low hydrogenation efficiency, long reaction times, difficulty in precisely controlling the degree of hydrogenation, and insufficient catalyst activity, requiring further optimization.

[0005] Hydrogenated nitrile butadiene rubber (HNBR) is another important specialty rubber obtained by selective hydrogenation of NBR. Through the saturated C=C double bonds in the main chain, it improves the material's heat resistance, ozone resistance, and aging resistance, while maintaining good oil resistance and mechanical strength. It is widely used in automotive seals, oilfield equipment, aerospace, and other fields. However, HNBR does not contain strongly polar groups such as carboxyl groups, and its adhesive properties, bonding strength with metal or fiber-reinforced materials, and resistance to certain chemical media are not as good as HXNBR. Furthermore, there is still room for improvement in the abrasion resistance and tear resistance of HNBR under extreme operating conditions.

[0006] Rubber blending modification is an effective means to improve the performance defects of single rubbers and achieve complementary properties. By mechanically mixing or melt blending two or more rubber materials, the overall performance of the materials can be optimized, costs reduced, and application areas expanded. HXNBR has excellent adhesion and chemical resistance, but poor processing flow and high cost; HNBR has good processing performance and heat and aging resistance, but its adhesion performance is relatively insufficient. Theoretically, blending HXNBR with HNBR can achieve complementary advantages, maintaining excellent adhesion and chemical resistance while improving processing performance and reducing costs. However, current research on HXNBR / HNBR blends is limited, especially regarding the blending process and parameter control of HXNBR and HNBR, which lacks in-depth research and represents a technological gap.

[0007] Based on this, the present invention provides a hydrogenated carboxylated nitrile butadiene rubber / hydrogenated nitrile butadiene rubber blend and its preparation method, develops and designs an efficient and controllable HXNBR preparation method, and systematically studies the blending of HXNBR / HNBR and its preparation method. This invention has important theoretical significance and practical value for promoting the development of high-performance special rubber materials and expanding their application fields. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide a blend of HXNBR / HNBR and its preparation method, solving the problems of difficult processing and high cost when HXNBR is used alone, improving the mechanical strength and chemical resistance of HNBR, and enhancing the overall performance of the blend. Simultaneously, the present invention also provides a method for preparing high-performance hydrogenated carboxylated nitrile butadiene rubber. This method achieves efficient and selective hydrogenation of carboxylated nitrile butadiene rubber by optimizing the emulsion hydrogenation process and catalyst system. The degree of hydrogenation reaction is controllable, the reaction efficiency is high, and the product performance is stable. By blending and modifying the prepared hydrogenated carboxylated nitrile butadiene rubber with HNBR, a more balanced HXNBR / HNBR blend with improved physical and mechanical properties and durability is obtained.

[0009] This invention can be achieved through the following technical solutions: The preparation of HXNBR / HNBR blends includes the following steps: Step S1 (First stage mixing): Add hydrogenated carboxylated nitrile butadiene rubber (HXNBR) and hydrogenated nitrile butadiene rubber (HNBR) to a mixer at a mass ratio of 50-90:10-50, and plasticize at 50-70℃ for 1-3 minutes; add activator and mix for 1-3 minutes; add plasticizer and reinforcing agent in two batches, with an interval of 1-3 minutes between each batch; clean by lifting the plug, and when the total mixing time reaches 6-10 minutes, discharge the rubber and let it cool at room temperature. The first stage mixing is now complete. Step S2 (two-stage mixing): Add the rubber compound after the first stage mixing to the internal mixer, add the vulcanizing agent and accelerator at 60-80℃, mix for 3-8 minutes until the rubber compound temperature reaches 90-130℃, then discharge the rubber; after thinning and triangular wrapping 6-10 times on the open mill, sheet the rubber compound; let the rubber compound stand at room temperature for 8-24 hours. Step S3 (vulcanization): Vulcanize the compound at 150-180℃ and 10-20 MPa for 8-25 minutes; after vulcanization, let the compound stand at room temperature for 12-24 hours before performance testing or use.

[0010] According to an embodiment of the present invention, in step S1, the mass of the HXNBR is 50-90 parts, preferably 60-70 parts.

[0011] According to an embodiment of the present invention, in step S1, the mass of the HNBR is 10-50 parts, preferably 30-40 parts.

[0012] According to an embodiment of the present invention, in step S1, the total amount of HXNBR and HNBR is 100 parts by weight, the activator is 1-10 parts, the plasticizer is 5-30 parts, and the reinforcing agent is 20-80 parts.

[0013] According to an embodiment of the present invention, in step S1, the total time for the mixing process is 6-10 minutes, preferably 8-10 minutes.

[0014] According to an embodiment of the present invention, in step S1, the initial temperature of the internal mixer is 50-70℃, preferably 55-65℃; the rotation speed is 40-80 rpm, preferably 50-70 rpm.

[0015] According to an embodiment of the present invention, in step S2, the amount of vulcanizing agent is 1-8 parts by weight, and the amount of accelerator is 0.5-5 parts.

[0016] According to an embodiment of the present invention, in step S2, the mixing time of the two-stage mixing is 3-8 minutes, preferably 5-7 minutes.

[0017] According to an embodiment of the present invention, in step S2, the discharge temperature of the two-stage mixing is 90-130℃, preferably 110-120℃.

[0018] According to an embodiment of the present invention, in step S3, the vulcanization temperature is 150-180°C, preferably 170-180°C.

[0019] According to an embodiment of the present invention, in step S3, the vulcanization pressure is 10-20 MPa, preferably 10-14 MPa.

[0020] According to an embodiment of the present invention, in step S3, the vulcanization time is 8-25 minutes, preferably 10-16 minutes.

[0021] According to an embodiment of the present invention, the rubber compound needs to be left at room temperature to allow the compounding agents to fully diffuse and the internal stress of the rubber compound to relax, which helps to improve the uniformity of the vulcanized rubber performance.

[0022] According to an embodiment of the present invention, the degree of hydrogenation of the HXNBR is 80-99%, preferably 90-98%.

[0023] According to an embodiment of the present invention, the carboxyl content of the HXNBR is 1-12%, preferably 3-7%.

[0024] According to an embodiment of the present invention, the acrylonitrile content in the HXNBR is 15-40 wt%, preferably 23-38 wt%.

[0025] According to an embodiment of the present invention, the degree of hydrogenation of the HNBR is 90-99%, preferably 95-99%.

[0026] According to an embodiment of the present invention, the acrylonitrile content in the HNBR is 30-50 wt%, preferably 36-43 wt%.

[0027] According to an embodiment of the present invention, the source of the HNBR is not particularly limited and can be a commercially available product.

[0028] According to an embodiment of the present invention, the reinforcing agent is carbon black, which is selected from one or more of N330, N326, N550, and N990, preferably N330 or N550.

[0029] According to an embodiment of the present invention, the plasticizer is selected from one or more of dioctyl phthalate (DOA), dioctyl phthalate (DOP), dibutyl phthalate (DBP), and trioctyl trimellitate (TOTM), preferably trioctyl trimellitate (TOTM).

[0030] According to an embodiment of the present invention, the vulcanizing agent is selected from one or more of 1,4-bis(tert-butylperoxyisopropyl)benzene (BIBP) and sulfur, preferably 1,4-bis(tert-butylperoxyisopropyl)benzene (BIBP).

[0031] According to an embodiment of the present invention, the activator is selected from one or more of zinc oxide (ZnO), magnesium oxide (MgO), and stearic acid (SA), preferably a combination of zinc oxide, magnesium oxide, and stearic acid.

[0032] According to an embodiment of the present invention, the accelerator is selected from one or more of triallyl isocyanate (TAIC), tetramethylthiuram disulfide (TMTD), and N-cyclohexyl-2-benzothiazolium amide (CBS). Preferably, it is triallyl isocyanate (TAIC).

[0033] According to an embodiment of the present invention, the HXNBR can be prepared by the following method: preparing a carboxylated nitrile rubber latex emulsion with a solid content of 5-55 wt%; mixing a ruthenium-based catalyst with the above carboxylated nitrile rubber latex emulsion to obtain an emulsion mixture; carrying out a hydrogenation reaction of the emulsion mixture in the presence of hydrogen; adding the reaction product dropwise to anhydrous ethanol to obtain a solid rubber, which is then dried to constant weight to obtain hydrogenated carboxylated nitrile rubber.

[0034] According to an embodiment of the present invention, the acrylonitrile content in the carboxylated nitrile latex is 15-40 wt%, preferably 23-38 wt%.

[0035] According to an embodiment of the present invention, the carboxyl content in the carboxyl nitrile latex is 1-12%, preferably 3-7%.

[0036] According to an embodiment of the present invention, the solid content of the carboxylated nitrile latex is 5-55 wt%, preferably 25-35 wt%.

[0037] According to an embodiment of the present invention, the solid content of the carboxylated nitrile latex in the hydrogenation reaction is 5-55 wt%, preferably 10-25 wt%.

[0038] According to an embodiment of the present invention, the catalyst is a laboratory-made ruthenium-based catalyst [RuCl2(=CH-O-C4H6ON)PCy3(X)][X=1,3-bis(trimethylphenyl)-2-imidazolinediyl], consisting entirely of [1,3-bis(trimethylphenyl)-2-imidazolinediyl]dichloro(2-oxo-1-pyrrolidinyl)methylenetricyclohexylphosphine ruthenium (C 44 H 64 Cl2N3OPRu).

[0039] According to an embodiment of the present invention, the mass of the catalyst in the hydrogenation reaction accounts for 0.01-0.2 wt% of the mass of the carboxylated acrylonitrile rubber, preferably 0.05-0.15 wt%.

[0040] According to an embodiment of the invention, the pressure in the hydrogenation reaction is 500-1500 psi (3.44-10.34 MPa), preferably 800-1100 psi (5.51-7.58 MPa).

[0041] According to an embodiment of the present invention, the temperature in the hydrogenation reaction is 70-150 °C, preferably 90-120 °C.

[0042] According to an embodiment of the present invention, the hydrogenation time in the hydrogenation reaction is 5-20 h, preferably 5-11 h.

[0043] According to an embodiment of the present invention, the rotation speed in the hydrogenation reaction is 250-600 rpm, preferably 300-400 rpm.

[0044] According to an embodiment of the present invention, there are no special restrictions on the source of carboxylated nitrile latex, which can be commercially available.

[0045] Beneficial effects of the present invention This invention provides a method for the hydrogenation preparation of HXNBR and a rubber composition in which HXNBR / HNBR are blended. It effectively solves the problems of high cost, difficulty in control, poor compatibility, and unbalanced overall performance in traditional hydrogenation processes. Through specific selection and optimization of the catalyst system and reaction conditions (such as temperature, pressure, and time), high efficiency and low cost are achieved. This method can achieve a high degree of hydrogenation (≥95%) under relatively mild conditions. The hydrogenation reaction is mild, requires no organic solvents, and the process is simple, reducing production energy consumption and purification costs. The unique hydrogenation and blending system gives the final product superior heat oxidation resistance and media resistance, as well as good mixing uniformity and molding flowability. This invention provides an economical and efficient HXNBR preparation route, and through innovative blending design, obtains a high-performance elastomer material with overall performance far exceeding that of a single component, meeting the demanding requirements of high-end oil seals, sealing components, automotive pipelines, and other applications.

[0046] Performance testing methods The hydrogenation conversion rate was calculated based on the hydrogenation conversion rate of unsaturated double bonds in the HXNBR molecular chain. It was determined by ¹H-NMR nuclear magnetic resonance spectroscopy. The double bond residual rate was calculated by comparing the integral area of ​​the characteristic hydrogen peak of the double bond in the rubber molecular chain before and after hydrogenation with the reference hydrogen peak.

[0047] Acrylonitrile content was determined using an elemental analyzer. The acrylonitrile content was calculated as follows: Acrylonitrile content (%) = N / 14 × 53 (relative molecular weight of acrylonitrile) × 100%.

[0048] The carboxyl content was determined using an elemental analyzer. The carboxyl content was calculated as follows: Carboxyl content (%) = O / 32 × 45 (relative molecular weight of carboxyl groups) × 100%.

[0049] The gel content was determined using the crosslinking density method. The sample was weighed in a 300-mesh nickel mesh box, then soaked and rinsed twice with methyl ethyl ketone (MEK) for 24 hours each time, and dried in a vacuum oven at 100°C to constant weight. The gel content (wt%) was calculated using the formula: Gel content (wt%) = (W3-W2) / W1 × 100%.

[0050] The vulcanization characteristics were tested according to GB / T16584-1996, with a test temperature of 180 ℃ and a test time of 20 min.

[0051] The oil resistance was tested according to GB / T1690-2010, with the oil medium being No. 3 standard oil, the test temperature being 150 ℃, and the test time being 72 h.

[0052] Oil resistance coefficient = [(tensile strength × elongation at break after oil resistance) / (tensile strength × elongation at break before oil resistance)] × 100%.

[0053] Tensile stress-strain properties were tested according to GB / T528-2009, with a tensile rate of 500 mm / min.

[0054] The hot air aging performance was tested according to GB / T3512-2014, with a test temperature of 150℃ and a test time of 72 h.

[0055] Compression set was tested according to GB / T7759-2009, at a test temperature of 150℃ for 72 hours.

[0056] Mooney viscosity was tested according to GB / T1232.1-2016. Attached Figure Description

[0057] Figure 1 Comparison of FT-IR spectra of XNBR before and after hydrogenation Figure 1 The figures show the FT-IR spectra of XNBR and HXNBR with a hydrogenation degree of 98% under reaction pressure of 6.89 MPa and catalyst dosage of 0.05% wt%. The figures show that the XNBR before hydrogenation and the HXNBR after hydrogenation have a similar wavelength at 2236 cm⁻¹. -1 The characteristic C≡N peak at 1700 cm⁻¹ -1 The C=O characteristic peak at 970 cm⁻¹ remained essentially unchanged, indicating that this ruthenium-based catalyst can complete the hydrogenation reaction without damaging the nitrile group; while at 970 cm⁻¹... -1 The peak intensity of the 1,4-trans structure at 723 cm⁻¹ decreases after hydrogenation; -1 The methylene peak at the xylene group gradually intensifies. Therefore, this hydrogenation process successfully achieves selective hydrogenation of C=C on the XNBR molecular chain while retaining the original nitrile groups of XNBR. Detailed Implementation

[0058] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0059] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0060] I. Preparation of Hydrogenated Carboxylated Acrylonitrile Butadiene Rubber (HXNBR) Example

[0061] A 500 mL stainless steel high-pressure reactor equipped with a temperature control device, a stirrer, and a hydrogen addition point was used. A carboxylated nitrile butadiene rubber latex with an acrylonitrile content of 30 wt%, a solid content of 32.6%, and a carboxyl group content of 4.48% was used. At room temperature, 138 mL of the above carboxylated nitrile butadiene rubber latex was added to the reactor along with water to prepare a carboxylated nitrile butadiene emulsion with a solid content of 15%. A catalyst, [RuCl2(=CH-O-C4H6ON)PCy3(X)][X=1,3-bis(trimethylphenyl)-2-imidazolinediyl],[1,3-bis(trimethylphenyl)-2-imidazolinediyl]dichloro(2-oxo-1-pyrrolidinyl)methylenetricyclohexylphosphine ruthenium (C44H64Cl2N3OPRu), was added, with the mass percentage of the carboxylated nitrile butadiene rubber in the emulsion being 0.15 wt%. A two-stage heating process was then employed: the first stage increased the temperature to 100 °C at a rate of 5 °C / min, and the second stage increased the temperature to 115 °C at a rate of 1 °C / min. The hydrogenation reaction was carried out at 115 °C, 400 rpm, and a hydrogen pressure of 1000 psi (6.89 MPa) for 7 h, yielding a hydrogenated carboxylated acrylonitrile butadiene rubber (HXNBR) emulsion with a hydrogenation degree of 98%. After the reaction, the latex was coagulated using ethanol to obtain hydrogenated carboxylated acrylonitrile butadiene rubber (HXNBR).

[0062] The product was tested and found to have a hydrogenation degree of 98%, a carboxyl content of 4.50%, an acrylonitrile content of 29.80 wt%, a Mooney viscosity (ML (1+4)) of 75 at 100℃, a gel content of 0.53%, and a volatile content of 99 wt%.

[0063] Example 2: A 500 mL stainless steel high-pressure reactor equipped with a temperature control device, a stirrer, and a hydrogen addition point was used. A carboxylated nitrile rubber latex with an acrylonitrile content of 30 wt%, a solid content of 32.6%, and a carboxyl group content of 4.48% was used. At room temperature, 138 mL of the above carboxylated nitrile rubber latex was added to the reactor along with water to prepare a carboxylated nitrile emulsion with a solid content of 15%. [RuCl2(=CH-O-C4H6ON)PCy3(X)][X=1,3-bis(trimethylphenyl)-2-imidazolinide], full name [1,3-bis(trimethylphenyl)-2-imidazolinide]dichloro(2-oxo-1-pyrrolidinyl)methylenetricyclohexylphosphineruthenium (C 44 H 64 The mass percentage of the Cl2N3OPRu catalyst to the carboxylated acrylonitrile rubber in the emulsion was 0.05 wt%. A two-stage heating process was then employed: the first stage increased the temperature to 100 °C at 5 °C / min, and the second stage increased the temperature to 115 °C at 1 °C / min. The hydrogenation reaction was carried out at 115 °C, 400 rpm, and a hydrogen pressure of 1000 psi (6.89 MPa) for 7 h to obtain a hydrogenated carboxylated acrylonitrile rubber (HXNBR) emulsion with a hydrogenation degree of 90%. After the reaction, the latex was coagulated using ethanol to obtain hydrogenated carboxylated acrylonitrile rubber (HXNBR).

[0064] Tests showed that its hydrogenation degree was 90%, carboxyl content was 4.47%, acrylonitrile content was 30.00 wt%, Mooney viscosity (ML (1+4)) at 100℃ was 70, gel content was 0.51%, and volatile matter was 99 wt%.

[0065] Example 3: A 500 mL stainless steel high-pressure reactor equipped with a temperature control device, a stirrer, and a hydrogen addition point was used. A carboxylated nitrile rubber latex with an acrylonitrile content of 30 wt%, a solid content of 32.6%, and a carboxyl group content of 4.48% was used. At room temperature, 138 mL of the above carboxylated nitrile rubber latex was added to the reactor along with water to prepare a carboxylated nitrile emulsion with a solid content of 15%. [RuCl2(=CH-O-C4H6ON)PCy3(X)][X=1,3-bis(trimethylphenyl)-2-imidazolinide], full name [1,3-bis(trimethylphenyl)-2-imidazolinide]dichloro(2-oxo-1-pyrrolidinyl)methylenetricyclohexylphosphineruthenium (C 44 H 64The mass percentage of carboxylated acrylonitrile rubber in the emulsion containing the Cl2N3OPRu catalyst was 0.15 wt%. A two-stage heating process was then employed: the first stage increased the temperature to 80 °C at 5 °C / min, and the second stage increased the temperature to 100 °C at 1 °C / min. The hydrogenation reaction was carried out at 100 °C, 400 rpm, and a hydrogen pressure of 1000 psi (6.89 MPa) for 7 h to obtain a hydrogenated carboxylated acrylonitrile rubber (HXNBR) emulsion with a hydrogenation degree of 75%. After the reaction, the latex was coagulated using ethanol to obtain hydrogenated carboxylated acrylonitrile rubber (HXNBR).

[0066] The product was tested and found to have a hydrogenation degree of 85%, a carboxyl content of 4.51%, an acrylonitrile content of 30.2 wt%, a Mooney viscosity (ML(1+4)) of 62 at 100℃, a gel content of 0.47%, and a volatile content of 99 wt%.

[0067] Example 4: A 500 mL stainless steel high-pressure reactor equipped with a temperature control device, a stirrer, and a hydrogen addition point was used. A carboxylated nitrile butadiene rubber latex with an acrylonitrile content of 30 wt%, a solid content of 32.6%, and a carboxyl group content of 4.48% was used. At room temperature, 138 mL of the above carboxylated nitrile butadiene rubber latex was added to the reactor along with water to prepare a carboxylated nitrile butadiene emulsion with a solid content of 15%. [RuCl2(=CH-O-C4H6ON)PCy3(X)][X=1,3-bis(trimethylphenyl)-2-imidazolinide], full name [1,3-bis(trimethylphenyl)-2-imidazolinide]dichloro(2-oxo-1-pyrrolidinyl)methylenetricyclohexylphosphineruthenium (C 44 H 64 The Cl2N3OPRu catalyst and the carboxylated acrylonitrile rubber in the emulsion accounted for 0.15 wt% of the total mass. A two-stage heating process was then employed: the first stage increased the temperature to 100 °C at 5 °C / min, and the second stage increased it to 115 °C at 1 °C / min. The hydrogenation reaction was carried out at 115 °C, 400 rpm, and a hydrogen pressure of 700 psi (4.82 MPa) for 7 h, yielding a hydrogenated carboxylated acrylonitrile rubber (HXNBR) emulsion with a hydrogenation degree of 83%. After the reaction, the latex was coagulated using ethanol to obtain hydrogenated carboxylated acrylonitrile rubber (HXNBR).

[0068] Tests showed that its hydrogenation degree was 98%, carboxyl content was 4.50%, acrylonitrile content was 30.03wt%, Mooney viscosity (ML (1+4)) at 100℃ was 80, gel content was 0.49%, and volatile matter was 99wt%.

[0069] II. Preparation of HXNBR / HNBR Blend Adhesive Example

[0070] The preparation method of hydrogenated carboxylated butadiene-acrylonitrile rubber is as described in Example 1.

[0071] Formula and dosage of each component: HXNBR (prepared in Example 1, 98% hydrogenation, 29.8 wt% acrylonitrile, 4.50% carboxyl content) 90 phr, HNBR (commercially available, 98% hydrogenation, 40 wt% acrylonitrile) 10 phr, Carbon black N550 50 phr, Zinc oxide (ZnO) 5 phr, Stearic acid (SA) 1 phr, Magnesium oxide (MgO) 3 phr, Plasticizer TOTM 10 phr, Crosslinking agent BIPB 2 phr, Co-crosslinking agent TAIC 2 phr Step S1 (first stage of mixing): Add raw rubber HNBR / HXNBR at a mass ratio of 10 / 90 to an internal mixer (set temperature 60℃, speed 60 rpm) for plasticizing. Add ZnO, SA and MgO at 2 min. Add half of the TOTM and carbon black mixture at 3 min. Add the other half of the carbon black and TOTM mixture after 1 min. Clean the mixture at 6 min. Discharge the rubber at 8 min and let the mixed rubber compound stand at room temperature. The first stage of mixing is complete. Step S2 (two-stage mixing): After the rubber compound cools down, perform two-stage mixing: First, add the rubber compound that has been mixed in the first stage to the internal mixer and add BIPB and TAIC. Mix for 6 minutes and then discharge the rubber. Then, perform the triangular bagging operation 6 times on the open mill and then sheet it. Finally, let the mixed rubber rest at room temperature for 12 hours in preparation for vulcanization. Step S3 (vulcanization molding): Vulcanize the compound at 180 ℃ for 10 min under a vulcanization pressure of 10 MPa. After vulcanization, let the compound stand for 12 h before conducting performance tests.

[0072] Example 6: The preparation method of hydrogenated carboxylated butadiene-acrylonitrile rubber is as described in Example 1.

[0073] Formulation and dosage of each component: HXNBR (prepared in Example 1, hydrogenation degree 98%, acrylonitrile content 29.8wt%, carboxyl content 4.50%) 80 phr, HNBR (commercially available, hydrogenation degree 98%, acrylonitrile content 40wt%) 20 phr, carbon black N550 50 phr, zinc oxide (ZnO) 5 phr, stearic acid (SA) 1 phr, magnesium oxide (MgO) 3 phr, plasticizer TOTM 10 phr, crosslinking agent BIPB 2 phr, co-crosslinking agent TAIC 2 phr.

[0074] Step S1 (first stage of mixing): Add raw rubber HNBR / HXNBR at a mass ratio of 20 / 80 to an internal mixer (set temperature 60℃, speed 60 rpm) for plasticizing. Add ZnO, SA and MgO after 2 min. Add half of the TOTM and carbon black mixture after 3 min. Add the other half of the carbon black and TOTM mixture after 1 min. Discharge the rubber after 8 min and let the mixed rubber compound stand at room temperature. The first stage of mixing is complete. Step S2 (two-stage mixing): After the rubber compound cools down, perform two-stage mixing: First, add the rubber compound that has been mixed in the first stage to the internal mixer and add BIPB and TAIC. Mix for 5 minutes and then discharge the rubber. Then, perform the triangular bagging operation 6 times on the open mill and then sheet it. Finally, let the mixed rubber rest at room temperature for 12 hours in preparation for vulcanization. Step S3 (vulcanization molding): The compound is vulcanized at 180 ℃ for 9 min under a vulcanization pressure of 10 MPa. After vulcanization, the compound is left to stand for 12 h before performance testing.

[0075] Example 7: The preparation method of hydrogenated carboxylated butadiene-acrylonitrile rubber is as described in Example 1.

[0076] Formulation and dosage of each component: HXNBR (prepared in Example 1, hydrogenation degree 98%, acrylonitrile content 29.8wt%, carboxyl content 4.50%) 70 phr, HNBR (commercially available, hydrogenation degree 98%, acrylonitrile content 40wt%) 30 phr, carbon black N550 50 phr, zinc oxide (ZnO) 5 phr, stearic acid (SA) 1 phr, magnesium oxide (MgO) 3 phr, plasticizer TOTM 10 phr, crosslinking agent BIPB 2 phr, co-crosslinking agent TAIC 2 phr.

[0077] Step S1 (first stage of mixing): Add raw rubber HNBR / HXNBR at a mass ratio of 30 / 70 to an internal mixer (set temperature 60℃, speed 60 rpm) for plasticizing. Add ZnO, SA and MgO at 2 min. Add half of the TOTM and carbon black mixture at 3 min. Add the other half of the carbon black and TOTM mixture after 1.5 min. Clean the mixture after 6 min. Discharge the rubber at 8 min and let the mixed rubber compound stand at room temperature. The first stage of mixing is complete. Step S2 (two-stage mixing): After the rubber compound cools down, perform two-stage mixing: First, add the rubber compound that has been mixed in the first stage to the internal mixer and add BIPB and TAIC. Mix for 6 minutes and then discharge the rubber. Then, perform the triangular bagging operation 6 times on the open mill and then sheet it. Finally, let the mixed rubber rest at room temperature for 12 hours in preparation for vulcanization. Step S3 (vulcanization molding): The compound is vulcanized at 180 ℃ for 8 min and vulcanization pressure of 12 MPa. After vulcanization, the compound is left to stand for 12 h before performance testing.

[0078] Example 8: The preparation method of hydrogenated carboxylated butadiene-acrylonitrile rubber is as described in Example 1.

[0079] Formulation and dosage of each component: HXNBR (prepared in Example 1, hydrogenation degree 98%, acrylonitrile content 29.8wt%, carboxyl content 4.50%) 60 phr, HNBR (commercially available, hydrogenation degree 98%, acrylonitrile content 40wt%) 40 phr, carbon black N550 50 phr, zinc oxide (ZnO) 5 phr, stearic acid (SA) 1 phr, magnesium oxide (MgO) 3 phr, plasticizer TOTM 10 phr, crosslinking agent BIPB 2 phr, co-crosslinking agent TAIC 2 phr.

[0080] Step S1 (first stage of mixing): Add raw rubber HNBR / HXNBR in a mass ratio of 40 / 60 to an internal mixer (set temperature 60℃, speed 60 rpm) for plasticizing. Add ZnO, SA and MgO at 2 min. Add half of the TOTM and carbon black mixture at 3 min. Add the other half of the carbon black and TOTM mixture after 1 min. Clean the mixture at 6 min. Discharge the rubber at 8 min and let the mixed rubber compound stand at room temperature. The first stage of mixing is complete. Step S2 (two-stage mixing): After the rubber compound cools down, perform two-stage mixing: First, add the rubber compound that has been mixed in the first stage to the internal mixer and add BIPB and TAIC. Mix for 6 minutes and then discharge the rubber. Then, perform the triangular bagging operation 6 times on the open mill and then sheet it. Finally, let the mixed rubber rest at room temperature for 12 hours in preparation for vulcanization. Step S3 (vulcanization molding): The compound is vulcanized at 180 ℃ for 8 min and vulcanization pressure of 10 MPa. After vulcanization, the compound is left to stand for 12 h before performance testing.

[0081] Example 9 The preparation method of hydrogenated carboxylated butadiene-acrylonitrile rubber is as described in Example 2.

[0082] Formulation and dosage of each component: HXNBR (prepared in Example 1, hydrogenation degree 90%, acrylonitrile content 30.0wt%) 60 phr, HNBR (commercially available, hydrogenation degree 98%, acrylonitrile content 40wt%) 40 phr, carbon black N550 50 phr, zinc oxide (ZnO) 5 phr, stearic acid (SA) 1 phr, magnesium oxide (MgO) 3 phr, plasticizer TOTM 10 phr, crosslinking agent BIPB 2 phr, co-crosslinking agent TAIC 2 phr.

[0083] Step S1 (first stage of mixing): Add raw rubber HNBR / HXNBR in a mass ratio of 40 / 60 to an internal mixer (set temperature 60℃, speed 60 rpm) for plasticizing. Add ZnO, SA and MgO after 3 min. Add half of the TOTM and carbon black mixture after another 3 min. Add the other half of the carbon black and TOTM mixture after another 1 min. Clean the mixture after 8 min. Discharge the rubber after 10 min and let the mixed rubber compound stand at room temperature. The first stage of mixing is complete. Step S2 (two-stage mixing): After the rubber compound cools down, perform two-stage mixing: First, add the rubber compound that has been mixed in the first stage to the internal mixer and add BIPB and TAIC. Mix for 6 minutes and then discharge the rubber. Then, perform the triangular bagging operation 6 times on the open mill and then sheet it. Finally, let the mixed rubber rest at room temperature for 12 hours in preparation for vulcanization. Step S3 (vulcanization molding): Vulcanize the compound at 170 ℃ for 12 min under a vulcanization pressure of 10 MPa. After vulcanization, let the compound stand for 12 h before conducting performance tests.

[0084] Example 10 The preparation method of hydrogenated carboxylated butadiene-acrylonitrile rubber is as described in Example 1.

[0085] Formulation and dosage of each component: HXNBR (prepared in Example 1, hydrogenation degree 98%, acrylonitrile content 29.8wt%, carboxyl content 4.50%) 60 phr, HNBR (commercially available, hydrogenation degree 98%, acrylonitrile content 40wt%) 40 phr, carbon black N550 50 phr, zinc oxide (ZnO) 5 phr, stearic acid (SA) 1 phr, magnesium oxide (MgO) 3 phr, plasticizer TOTM 10 phr, crosslinking agent BIPB 2.3 phr, co-crosslinking agent TAIC 1.4 phr.

[0086] Step S1 (first stage of mixing): Add raw rubber HNBR / HXNBR in a mass ratio of 40 / 60 to an internal mixer (set temperature 60℃, speed 60 rpm) for plasticizing. Add ZnO, SA and MgO at 2 min. Add half of the TOTM and carbon black mixture at 3 min. Add the other half of the carbon black and TOTM mixture after 1.5 min. Clean the mixture at 6 min. Discharge the rubber at 8 min and let the mixed rubber compound stand at room temperature. The first stage of mixing is complete. Step S2 (two-stage mixing): After the rubber compound cools down, perform two-stage mixing: First, add the rubber compound that has been mixed in the first stage to the internal mixer and add BIPB and TAIC. Mix for 7 minutes and then discharge the rubber. Then, perform the triangular bagging operation 6 times on the open mill and then sheet it. Finally, let the mixed rubber rest at room temperature for 12 hours in preparation for vulcanization. Step S3 (vulcanization molding): Vulcanize the compound at 180 ℃ for 10 min under a vulcanization pressure of 10 MPa. After vulcanization, let the compound stand for 12 h before conducting performance tests.

[0087] Comparative Example 1: The preparation method of hydrogenated carboxylated butadiene-acrylonitrile rubber is as described in Example 1.

[0088] Formulation and dosage of each component: HXNBR (prepared in Example 1, hydrogenation degree 98%, acrylonitrile content 29.8wt%, carboxyl content 4.50%) 100 phr, carbon black N550 50 phr, zinc oxide (ZnO) 5 phr, stearic acid (SA) 1 phr, magnesium oxide (MgO) 3 phr, plasticizer TOTM 10 phr, crosslinking agent BIPB 2 phr, co-crosslinking agent TAIC 2 phr.

[0089] Step S1 (first stage of mixing): Add 100 parts of raw rubber HXNBR to an internal mixer (set temperature 60℃, speed 60rpm) for plasticizing. Add ZnO, SA and MgO at 2 min. Add half of the TOTM and carbon black mixture at 3 min. Add the other half of the carbon black and TOTM mixture after 1 min. Clean the mixture at 6 min. Discharge the rubber at 8 min and let the mixed rubber compound stand at room temperature. The first stage of mixing is complete. Step S2 (two-stage mixing): After the rubber compound cools down, perform two-stage mixing: First, add the rubber compound that has been mixed in the first stage to the internal mixer and add BIPB and TAIC. Mix for 6 minutes and then discharge the rubber. Then, perform the triangular bagging operation 6 times on the open mill and then sheet it. Finally, let the mixed rubber rest at room temperature for 12 hours in preparation for vulcanization. Step S3 (vulcanization molding): Vulcanize the compound at 180 ℃ for 10 min under a vulcanization pressure of 10 MPa. After vulcanization, let the compound stand for 12 h before conducting performance tests.

[0090] Comparative Example 2: Formulation and dosage of each component: HNBR (commercially available, hydrogenation degree 98%, acrylonitrile content 40wt%) 100 phr, carbon black N550 50 phr, zinc oxide (ZnO) 5 phr, stearic acid (SA) 1 phr, magnesium oxide (MgO) 3 phr, plasticizer TOTM 10 phr, crosslinking agent BIPB 2 phr, co-crosslinking agent TAIC 2 phr.

[0091] Step S1 (first stage of mixing): Add 100 parts of raw rubber HNBR to a mixer (set temperature 60℃, speed 60rpm) for plasticizing. Add ZnO, SA and MgO at 2 min. Add half of the TOTM and carbon black mixture at 3 min. Add the other half of the carbon black and TOTM mixture after 1 min. Clean the mixture at 6 min. Discharge the rubber at 8 min and let the mixed rubber compound stand at room temperature. The first stage of mixing is complete. Step S2 (two-stage mixing): After the rubber compound cools down, perform two-stage mixing: First, add the rubber compound that has been mixed in the first stage to the internal mixer and add BIPB and TAIC. Mix for 6 minutes and then discharge the rubber. Then, perform the triangular bagging operation 6 times on the open mill and then sheet it. Finally, let the mixed rubber rest at room temperature for 12 hours in preparation for vulcanization. Step S3 (vulcanization molding): Vulcanize the compound at 180 ℃ for 10 min under a vulcanization pressure of 10 MPa. After vulcanization, let the compound stand for 12 h before conducting performance tests.

[0092] Comparative Example 3 The preparation method of XNBR / HNBR blend is as follows: Formulation and dosage of each component: XNBR (laboratory-made, carboxyl content 4.48%, acrylonitrile content 30.00wt%) 60 phr, HNBR (commercially available, hydrogenation degree 98%, acrylonitrile content 40wt%) 40 phr, carbon black N550 50 phr, zinc oxide (ZnO) 5 phr, stearic acid (SA) 1 phr, magnesium oxide (MgO) 3 phr, plasticizer TOTM 10 phr, crosslinking agent BIPB 2 phr, co-crosslinking agent TAIC 2 phr.

[0093] Step S1 (first stage of mixing): Add raw rubber XNBR / HNBR at a mass ratio of 40 / 60 to an internal mixer (set temperature 60℃, speed 60 rpm) for plasticizing. Add ZnO, SA and MgO at 2 min. Add half of the TOTM and carbon black mixture at 3 min. Add the other half of the carbon black and TOTM mixture after 1 min. Clean the mixture at 6 min. Discharge the rubber at 8 min and let the mixed rubber compound stand at room temperature. The first stage of mixing is complete. Step S2 (two-stage mixing): After the rubber compound cools down, perform two-stage mixing: First, add the rubber compound that has been mixed in the first stage to the internal mixer and add BIPB and TAIC. Mix for 6 minutes and then discharge the rubber. Then, perform the triangular bagging operation 6 times on the open mill and then sheet it. Finally, let the mixed rubber rest at room temperature for 12 hours in preparation for vulcanization. Step S3 (vulcanization molding): Vulcanize the compound at 180 ℃ for 10 min under a vulcanization pressure of 10 MPa. After vulcanization, let the compound stand for 12 h before conducting performance tests.

[0094] The mechanical properties, oil resistance, and aging resistance of Examples 5-10 and Comparative Examples 1-3 were tested, and the results are as follows: Table 1 Properties of the blended products from Examples 5-10 and Comparative Examples 1-3

[0095]

[0096] As demonstrated in Examples 1-4 of this invention, the hydrogenated carboxylated nitrile butadiene rubber (HXNBR) prepared by the catalytic hydrogenation method provided by this invention can achieve an optimal degree of hydrogenation of 98%, significantly improving the material's heat resistance, oxidation resistance, and ozone resistance. Its Mooney viscosity (ML 1+4) at 100℃ is 58-78, exhibiting good processability and selectability as needed. This HXNBR has a gel content of less than 0.53% and a volatile content of less than 1.0%. The hydrogenation process is mild and controllable, resulting in high product purity and stable quality. Simultaneously, the carboxyl content is maintained at 4-5%, effectively facilitating subsequent crosslinking reactions.

[0097] As demonstrated in Examples 5-10 and Comparative Examples 1-3 of this invention, the HXNBR and HNBR blend system exhibits excellent comprehensive performance, possessing the technical characteristics of controllable vulcanization characteristics, balanced mechanical properties, and synergistic improvement in oil resistance and heat aging resistance, showing significant advantages compared to single-type adhesives. As the HNBR proportion increases from 0% to 40%, the maximum torque (MH) and torque difference (MH-ML) of the blend gradually decrease, and the crosslinking network density decreases accordingly. This is because HNBR dilutes the carboxyl group concentration of HXNBR, causing the crosslinking network to transform from predominantly ionic crosslinking to a hybrid crosslinking network with both ionic and covalent bonds. In terms of mechanical properties, the hardness and tensile strength of the blend decrease slightly with increasing HNBR proportion, but effectively improve elongation at break, significantly enhancing the material's toughness. In terms of oil resistance, all blended adhesives exhibited significantly higher oil resistance coefficients than pure HXNBR and pure HNBR, with an increasing trend in oil resistance as the proportion of HNBR increased, reaching a peak at a blend ratio of 60 / 40. This demonstrates a clear synergistic effect, avoiding the over-structuring problem of pure HXNBR while compensating for the significant strength loss of pure HNBR. Regarding heat aging resistance, the blended adhesives showed significantly better aging coefficients and compression set than single adhesives, with a substantial improvement in elastic recovery. Furthermore, high-hydrogenated HXNBR significantly enhanced the heat aging resistance of the blended system, and the saturated chain structure of HXNBR forms the basis for the synergistic performance of the blended system.

[0098] Considering oil resistance, heat aging resistance, and mechanical properties, the optimal mass ratio of HXNBR / HNBR is 60 / 40 to 70 / 30. With this ratio, the blended adhesive has an oil resistance coefficient of ≥90%, an aging coefficient of ≥85%, a tensile strength of ≥24 MPa, and a compression set of ≤21%. It has excellent overall performance and is suitable for applications with stringent requirements for heat resistance, oil resistance, and dynamic sealing performance, such as automotive seals and oilfield seals.

Claims

1. A method for preparing a blend of hydrogenated carboxylated butadiene-acrylonitrile rubber and hydrogenated butadiene-acrylonitrile rubber, characterized in that, Includes the following steps: Step S1 (first stage of mixing): Add 50-90 parts of hydrogenated carboxylated nitrile butadiene rubber (HXNBR) and 10-50 parts of hydrogenated nitrile butadiene rubber (HNBR) to a mixer and plasticize at 50-70℃ for 1-3 minutes; add 1-10 parts of activator and mix for 1-3 minutes; add 5-30 parts of plasticizer and 20-80 parts of reinforcing agent in two batches, with an interval of 1-3 minutes between each batch; clean by lifting the plug, and when the total mixing time reaches 6-10 minutes, discharge the rubber and let it cool at room temperature; Step S2 (two-stage mixing): Add the rubber compound after the first stage mixing to the internal mixer, add 1-8 parts of vulcanizing agent and 0.5-5 parts of accelerator at 60-80℃, mix for 3-8 minutes until the rubber compound temperature reaches 90-130℃, then discharge the rubber; after thinning and triangular wrapping 6-10 times on the open mill, sheet the rubber compound; let the rubber compound stand at room temperature for 8-24 hours. Step S3 (vulcanization molding): Vulcanize the compound at a temperature of 150-180℃ and a pressure of 10-20 MPa for 8-25 minutes; Wherein, the number of portions refers to the number of weight portions.

2. A blended adhesive of HXNBR / HNBR, characterized in that, By weight, it includes the following components: 50-90 parts of hydrogenated carboxylated nitrile butadiene rubber (HXNBR), 10-50 parts of hydrogenated nitrile butadiene rubber (HNBR), 1-10 parts of activator, 5-30 parts of plasticizer, 20-80 parts of reinforcing agent, 1-8 parts of vulcanizing agent, and 0.5-5 parts of accelerator.

3. A method for preparing hydrogenated carboxylated butadiene-acrylonitrile rubber, characterized in that, Includes the following steps: A carboxylated nitrile butadiene latex with a solid content of 5-55 wt% was prepared by formulating a carboxylated nitrile butadiene latex with an acrylonitrile content of 15-40 wt% and a carboxyl group content of 1-12%. A ruthenium-based catalyst was mixed with the above carboxylated nitrile butadiene latex to obtain an emulsion mixture. The solid content of the carboxylated nitrile butadiene latex during the hydrogenation reaction was 10-25 wt%. The emulsion mixture was subjected to hydrogenation reaction under the conditions of hydrogen pressure of 5.51-7.58 MPa, reaction temperature of 90-120℃, reaction time of 5-11 hours, and stirring speed of 300-400 rpm. The reacted material was dropped into anhydrous ethanol to obtain a solid rubber, which was dried to constant weight to obtain hydrogenated carboxylated nitrile butadiene rubber.

4. The preparation method according to claim 1, characterized in that, In step S1, the total amount of HXNBR and HNBR is 100 parts by weight, with 60-70 parts of HXNBR and 30-40 parts of HNBR.

5. The preparation method according to claim 1 or 4, characterized in that, The HXNBR has a hydrogenation degree of 90-98%, a carboxyl content of 3-7%, and an acrylonitrile content of 23-38 wt%; the HNBR has a hydrogenation degree of 95-99% and an acrylonitrile content of 36-43 wt%.

6. The preparation method according to any one of claims 1, 4, or 5, characterized in that, The reinforcing agent is carbon black, which is selected from one or more of N330, N326, N550, and N990; the plasticizer is trioctyl trimellitate; the vulcanizing agent is 1,4-bis(tert-butylperoxyisopropyl)benzene; and the accelerator is triallyl isocyanurate.

7. The preparation method according to claim 3, characterized in that, The ruthenium-based catalyst is [RuCl2(=CH-O-C4H6ON)PCy3(X)][X=1,3-bis(trimethylphenyl)-2-imidazoline alkylene], full name [1,3-bis(trimethylphenyl)-2-imidazoline alkylene]dichloro(2-oxo-1-pyrrolidinyl)methylenetricyclohexylphosphine ruthenium (C 44 H 64 Cl2N3OPRu), the mass of the catalyst is 0.05-0.15 wt% of the mass of carboxylated nitrile rubber.

8. The preparation method according to claim 3 or 7, characterized in that, The hydrogenation degree of the prepared hydrogenated carboxylated acrylonitrile rubber is 90-98%, the carboxyl content is 3-7%, and the acrylonitrile content is 23-38 wt%.

9. The blended adhesive according to claim 2, characterized in that, By weight, HXNBR weighs 60-70 parts, and HNBR weighs 30-40 parts.

10. The blended adhesive according to claim 2 or 9, characterized in that, The oil resistance coefficient of the blended adhesive is ≥90%, the aging coefficient is ≥80%, and the tensile strength is ≥22 MPa.

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