Modified hydrogenated nitrile rubber and method for producing the same

Abstract

The present application relates to hydrogenated nitrile rubber technical field, specifically to a kind of modified hydrogenated nitrile rubber and its preparation method, the modified hydrogenated nitrile rubber contains grafting group derived from hydrogenated conjugated diene-styrene copolymer;Wherein, with the mass of modified hydrogenated nitrile rubber as benchmark, the grafting rate of the modified hydrogenated nitrile rubber is 5wt%-20wt%.The modified hydrogenated nitrile rubber of the present application effectively alleviates the problem that microcrystallization is prone to occur on the main chain of HNBR elastomer after hydrogenation, reduces glass transition temperature, improves the low-temperature flexibility of material, and also partially improves the heat-oxygen aging resistance of material.

Description

Technical Field

[0001] This invention relates to the field of hydrogenated nitrile butadiene rubber technology, specifically to a modified hydrogenated nitrile butadiene rubber and its preparation method. Background Technology

[0002] Hydrogenated nitrile butadiene rubber (HNBR) is a special synthetic rubber produced by selectively hydrogenating the butadiene units on the main chain of nitrile butadiene rubber (NBR). Its molecular chain consists of three parts: CN (-C≡N), methylene chains (-CH₂-), and a small amount of residual C=C. The retained cyano groups in the structure endow the polymer with excellent oil resistance, while the selective hydrogenation of the unsaturated C=C in the butadiene segments further enhances the NBR's resistance to heat and oxygen aging, and also reduces compression set to a certain extent. Therefore, HNBR is currently widely used in sealing components, oil-resistant hoses, and rubber industrial products for high-end equipment manufacturing, making it one of the special rubbers with extremely excellent comprehensive performance.

[0003] The temperature resistance of HNBR is generally between -40 ℃ and 150 ℃, and its low-temperature performance is controlled by multiple factors such as the acrylonitrile content, degree of hydrogenation, and molecular chain structure. In 1997, Zeon researchers discovered that the presence of only five or more consecutive tetramethylene units in the main chain of HNBR would promote the crystallization of the polymer material during stretching (Rubber Chemistry and Technology, 70, 1997, 839-854), resulting in poor low-temperature flexibility. Macroscopically, this manifests as the glass transition temperature (Tg) of HNBR typically not falling below -30 ℃, and accelerated deterioration at low temperatures.

[0004] To improve the low-temperature resistance of HNBR products, the simplest method is to modify the compound. This can be achieved by adding cold-resistant fillers and additives during the mixing process, or by blending HNBR with rubbers possessing excellent molecular chain flexibility, such as maleic anhydride-modified polybutadiene (CN114044953A). However, blended systems cannot achieve molecular-level blending bonds, making it relatively difficult to fundamentally overcome performance fluctuations in mechanical blending. Alternatively, low Mooney viscosity and low glass transition temperature can be achieved by designing HNBR compounds with a wide molecular weight distribution, but this method sacrifices some wear resistance and aging resistance, reducing product lifespan. Therefore, the current mainstream low-temperature resistant HNBR solution involves introducing a third monomer or a side group with good flexibility to break the highly ordered structure of the butadiene chain after hydrogenation saturation, thereby lowering the glass transition temperature (Tg) of the HNBR material and improving its low-temperature flexibility.

[0005] CN1471540A discloses a method for preparing HNBR with excellent low-temperature performance by introducing isoprene as a third monomer, wherein the isoprene content is not less than 25% of the conjugated diene. However, this method uses a traditional Wilkinson catalyst for hydrogenation, which requires a large amount of catalyst, and the price of Rh element fluctuates drastically, making it difficult to control production costs. CN105294939A discloses a method for preparing HNBR using dibutyl fumarate with a diester functional group as a copolymer third monomer. The introduction of this diester functional group can lower the glass transition temperature of the polymer and provide certain oil resistance. However, the polarity of the ester group is still weaker than that of the cyano group. The addition of a large amount of ester-containing third monomer reduces the content of bound acrylonitrile in the final product. Although this effectively lowers the glass transition temperature, it also sacrifices some oil resistance. CN115785305A discloses a method for preparing low Mooney hydrogenated nitrile butadiene rubber (HBNBR). The method utilizes its self-developed Zhan Catalysts to degrade and hydrogenate the raw nitrile butadiene rubber to obtain HBNBR with a wide molecular weight distribution. The lowest glass transition temperature in the final raw rubber sample can reach -47.1 ℃. However, it also has the disadvantages of low acrylonitrile content and wide molecular weight distribution. Summary of the Invention

[0006] The purpose of this invention is to overcome the problem of insufficient low-temperature resistance of existing hydrogenated nitrile butadiene rubber (HNBR) and to provide a modified HNBR and its preparation method. This modified HNBR exhibits increased flexibility of the molecular backbone, a lower glass transition temperature, good low-temperature resistance, chemical stability, and resistance to heat and oxygen aging, effectively broadening the application fields of HNBR.

[0007] To achieve the above objectives, the first aspect of the present invention provides a modified hydrogenated nitrile butadiene rubber containing graft groups derived from a hydrogenated conjugated diene-styrene copolymer; wherein, based on the mass of the modified hydrogenated nitrile butadiene rubber, the grafting rate of the modified hydrogenated nitrile butadiene rubber is 5wt%-20wt%.

[0008] A second aspect of the present invention provides a method for preparing modified hydrogenated nitrile butadiene rubber, the method comprising: In the presence of solvent, hydrogen, and catalyst, nitrile rubber undergoes a contact reaction with conjugated diene-styrene copolymer, including cross-metathesis and hydrogenation.

[0009] A third aspect of the present invention provides a modified hydrogenated nitrile butadiene rubber prepared by the preparation method described in the second aspect of the present invention.

[0010] Through the above technical solution, the present invention has at least the following beneficial effects: 1. The modified hydrogenated nitrile butadiene rubber of the present invention effectively alleviates the problem of microcrystals easily generated on the main chain of hydrogenated HNBR elastomer, reduces the glass transition temperature, and improves the low-temperature flexibility of the material.

[0011] 2. The modified hydrogenated nitrile rubber of the present invention has good low-temperature resistance and also partially improves the material's resistance to heat and oxygen aging, resulting in excellent overall performance.

[0012] 3. The modified hydrogenated nitrile butadiene rubber provided by this invention has the advantages of simple preparation method, mild reaction conditions and fast reaction rate, and the modified hydrogenated nitrile butadiene rubber prepared has excellent comprehensive properties.

[0013] 4. The modified hydrogenated nitrile rubber in this invention has a wide range of applications, considerable economic value and social benefits, and is expected to be applied in fields with harsh temperature conditions such as aerospace and high-end sealing materials. Attached Figure Description

[0014] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the modified hydrogenated nitrile rubber in Example 1. Detailed Implementation

[0015] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0016] The first aspect of the present invention provides a modified hydrogenated nitrile butadiene rubber containing graft groups derived from a hydrogenated conjugated diene-styrene copolymer; wherein, based on the mass of the modified hydrogenated nitrile butadiene rubber, the grafting rate of the modified hydrogenated nitrile butadiene rubber is 5wt%-20wt%.

[0017] In this invention, graft groups derived from hydrogenated conjugated diene-styrene copolymers are introduced into hydrogenated nitrile butadiene rubber, breaking the regularity of the original chain segments and enhancing the flexibility of the molecular backbone. This effectively alleviates the problem of microcrystal formation on the main chain of hydrogenated nitrile butadiene rubber. By enhancing the flexibility of the molecular backbone, the glass transition temperature of hydrogenated nitrile butadiene rubber is reduced and its low-temperature resistance is improved. In addition, the benzene ring can also enhance the rigidity of the rubber, giving the modified hydrogenated nitrile butadiene rubber good chemical stability and heat resistance.

[0018] According to one embodiment of the present invention, the grafting rate of the modified hydrogenated nitrile butadiene rubber is 8wt%-12wt%, based on the mass of the modified hydrogenated nitrile butadiene rubber.

[0019] In this invention, the hydrogenated conjugated diene-styrene copolymer refers to the grafting of conjugated diene-styrene's own intermolecular chain segments, either broken or intact, onto the main chain of nitrile rubber, while some or all of the double bonds are hydrogenated. The reaction sites in this invention are on the carbon-carbon double bonds. In nitrile rubber and conjugated diene-styrene copolymers, there are numerous carbon-carbon double bond sites, and reactions can occur between nitrile rubbers, between conjugated diene-styrene copolymers, and between nitrile rubber and conjugated diene-styrene copolymers. A schematic diagram of the general molecular structure of modified hydrogenated nitrile rubber is shown below, where x', x'', x''', y, and z represent the degree of polymerization of each structural unit, and R1, R2, R3, and R4 represent grafted group segments.

[0020]

[0021] In this invention, as long as the purpose of this invention can be achieved, there are no special restrictions on the selection of hydrogenated conjugated diene segments in the hydrogenated conjugated diene-styrene copolymer. For example, the hydrogenated conjugated diene segments in the hydrogenated conjugated diene-styrene copolymer are selected from C4-C8 hydrogenated conjugated diene segments, preferably selected from hydrogenated isoprene segments and / or hydrogenated butadiene segments.

[0022] In modified hydrogenated nitrile butadiene rubber, a high styrene content causes the material to lose its elastomer properties and become more like a resin material. Furthermore, the crystallinity of the material is also enhanced, which is detrimental to the low-temperature performance of the product. According to one embodiment of the present invention, based on the mass of the modified hydrogenated nitrile butadiene rubber, the styrene segment content in the modified hydrogenated nitrile butadiene rubber is ≤5 wt%, for example, 1 wt%, 1.7 wt%, 2 wt%, 3.2 wt%, 4.5 wt%, or 5 wt%.

[0023] According to one embodiment of the present invention, based on the mass of the modified hydrogenated nitrile butadiene rubber, the bound acrylonitrile content of the modified hydrogenated nitrile butadiene rubber is 22 wt%-31 wt%. The cyano group can impart good oil resistance to the polymer material, and the temperature resistance of the hydrogenated nitrile butadiene rubber is also affected by the bound acrylonitrile content.

[0024] Products with a high degree of hydrogenation exhibit superior resistance to heat and oxygen aging, and their compression set is also reduced to some extent. In this invention, the degree of hydrogenation can be selected within a wide range as long as the objective of this invention is achieved. According to one embodiment of the invention, the degree of hydrogenation of the modified hydrogenated nitrile rubber is 88 wt%-100 wt%.

[0025] When polymeric materials are used in environments below their glass transition temperature, the material transitions from an elastic state to a glassy state, resulting in brittle and hard macroscopic properties and potential failure. A lower glass transition temperature indicates better low-temperature performance. According to one embodiment of the present invention, the modified hydrogenated nitrile butadiene rubber has a glass transition temperature of -26 to -35 °C. The modified hydrogenated nitrile butadiene rubber of the present invention exhibits superior overall performance within the aforementioned glass transition temperature range.

[0026] In this invention, the molecular weight of the modified hydrogenated nitrile butadiene rubber can be selected within a wide range, as long as the objective of the invention is achieved. According to one embodiment of the invention, the number-average molecular weight of the modified hydrogenated nitrile butadiene rubber is 33,000-76,000.

[0027] In this invention, as long as the objective of the invention can be achieved, the molecular weight distribution of the modified hydrogenated nitrile butadiene rubber can be selected within a wide range. According to one embodiment of the invention, the molecular weight distribution index of the modified hydrogenated nitrile butadiene rubber is 1.8-4.7. The modified hydrogenated nitrile butadiene rubber of the aforementioned embodiment can be further processed more effectively.

[0028] A second aspect of the present invention provides a method for preparing modified hydrogenated nitrile butadiene rubber, the method comprising: In the presence of solvent, hydrogen, and catalyst, nitrile rubber undergoes a contact reaction with conjugated diene-styrene copolymer, including cross-metathesis and hydrogenation.

[0029] This invention utilizes olefin metathesis and hydrogenation processes to graft-modify nitrile rubber (NBR) using NBR and conjugated diene-styrene copolymer as raw materials, resulting in a product with excellent low-temperature resistance. Furthermore, the metathesis and hydrogenation reactions occur simultaneously, enabling the one-pot preparation of modified hydrogenated NBR. This preparation method is simple, with advantages such as mild reaction conditions and a fast reaction rate. The final modified hydrogenated NBR also exhibits good chemical stability and heat resistance.

[0030] Nitrile rubber is generally a solid. The addition of solvent in this invention is mainly to make the nitrile rubber form a liquid, which is conducive to the occurrence of the contact reaction in this invention.

[0031] According to a specific embodiment of the present invention, nitrile rubber is dissolved in a solvent to obtain a rubber solution. Under inert gas protection, a conjugated diene-styrene copolymer is added to the rubber solution and mixed. Then, a catalyst is added to the mixed rubber solution and hydrogen is introduced to carry out a contact reaction including cross metathesis and hydrogenation. After the reaction is completed, a coagulant is introduced and the mixture is dried to obtain modified hydrogenated nitrile rubber.

[0032] According to one embodiment of the present invention, the dissolution conditions include a temperature of 20-60 °C, preferably 50-60 °C.

[0033] According to one embodiment of the present invention, the dissolution conditions include a time of 2-24 h, preferably 3-6 h.

[0034] There are no particular restrictions on the selection of the conjugated diene segment as long as the objective of this invention can be achieved. According to one embodiment of the invention, the conjugated diene segment in the conjugated diene-styrene copolymer is selected from C4-C8 conjugated diene segments; preferably selected from isoprene segments and / or butadiene segments. This invention uses a butadiene-styrene copolymer as an example, but it should not be construed as limiting the invention.

[0035] In modified hydrogenated nitrile butadiene rubber, a high styrene content causes the material to lose its elastomer properties and become more like a resin material. Furthermore, the crystallinity of the material also increases, which is detrimental to the low-temperature performance of the product. In this invention, the content of the conjugated diene segment in the conjugated diene-styrene copolymer can be selected within a wide range, as long as the objective of the invention is achieved. According to one embodiment of the invention, the content of the conjugated diene segment in the conjugated diene-styrene copolymer is 50 wt%-80 wt%, preferably 50 wt%-70 wt%.

[0036] In this invention, the content of styrene segments in the conjugated diene-styrene copolymer can be selected within a wide range, as long as the objective of the invention can be achieved. According to one embodiment of the invention, the content of styrene segments in the conjugated diene-styrene copolymer is 20 wt%-50 wt%, preferably 30 wt%-50 wt%.

[0037] The conjugated diene-styrene copolymer of this invention can be prepared according to conventional methods in the art. A schematic diagram of the general molecular structure of the conjugated diene-styrene copolymer is shown below, where a, b, c, and d represent the degree of polymerization of each structural unit.

[0038]

[0039] This invention employs a conjugated diene-styrene copolymer with a low molecular weight. Hydrogenation of this copolymer helps reduce the number of continuous (-CH2-) segments in the product, and the (-CH2-) segments have a relatively small impact on the crystallinity of the main chain. According to one embodiment of the invention, the number-average molecular weight of the conjugated diene-styrene copolymer is 1000-3000; preferably 1500-3000.

[0040] The nitrile rubber in this invention can be obtained commercially or prepared using conventional methods in the art. The prepared nitrile rubber can then be used in one specific embodiment of this invention for preparing modified hydrogenated nitrile rubber. The general molecular structure of nitrile rubber is shown below, where x, y, and z represent the degree of polymerization of each structural unit.

[0041]

[0042] According to one embodiment of the present invention, the acrylonitrile content of the nitrile rubber is 25 wt%-35 wt%; preferably 25 wt%-33 wt%.

[0043] According to one embodiment of the present invention, the number average molecular weight of the nitrile rubber is 60,000-130,000; preferably 72,000-110,000.

[0044] According to one embodiment of the present invention, the molecular weight distribution index of the nitrile rubber is 1.5-3; preferably 2.5-3.

[0045] According to one embodiment of the present invention, the Mooney viscosity of the nitrile rubber is 45-55; preferably 47-52.

[0046] According to one embodiment of the present invention, the catalyst is at least one of Grubbs II, Grubbs III, Hoveyda-Grubbs II and Zhan Catalyst-1B; preferably Hoveyda-Grubbs II and / or Zhan Catalyst-1B.

[0047] According to one embodiment of the present invention, the mass ratio of the catalyst to nitrile rubber is 0.0002-0.0015:1; preferably 0.0003-0.0008:1.

[0048] According to the present invention, the solvent can be selected from a wide range. In one embodiment, the solvent is selected from at least one of methyl ethyl ketone, toluene, butanone, chloroform, chloroform, ethyl acetate, butyl butyrate, chlorobenzene, stilbene, toluene, and xylene; preferably at least one of chlorobenzene, toluene, and chloroform.

[0049] In this invention, there are no special restrictions on the amount of solvent used, as long as it enables the nitrile rubber to form the appropriate adhesive solution, which is conducive to the occurrence of the contact reaction in this invention. According to one embodiment of the invention, the mass ratio of the nitrile rubber to the solvent is 0.088-0.095:1.

[0050] According to one embodiment of the present invention, the mass ratio of the conjugated diene-styrene copolymer to the solvent is 0.005-0.012:1.

[0051] According to one embodiment of the present invention, the pressure of the hydrogen gas is 6-12 MPa.

[0052] According to one embodiment of the present invention, the conditions for the contact reaction include: a temperature of 70-160 °C; preferably 70-100 °C.

[0053] According to one embodiment of the present invention, the conditions for the contact reaction include: a time of 1-12 h; preferably 1-6 h.

[0054] According to one embodiment of the present invention, the method further includes coagulation after the contact reaction; after the contact reaction is completed, the adhesive solution is passed into a coagulant, the product is collected and dried. The coagulant is selected from alcohol solvents or water; preferably, it is a monohydric alcohol or dihydric alcohol of C1-C3 saturated alkanes.

[0055] A third aspect of the present invention provides a modified hydrogenated nitrile butadiene rubber prepared by the preparation method described in the second aspect of the present invention.

[0056] This invention utilizes an olefin metathesis catalyst to prepare modified hydrogenated nitrile butadiene rubber in a one-step process. The prepared modified hydrogenated nitrile butadiene rubber exhibits a low glass transition temperature, good low-temperature resistance, chemical stability, and resistance to heat and oxygen aging, effectively broadening the application fields of hydrogenated nitrile butadiene rubber.

[0057] The present invention will be described in detail below through embodiments.

[0058] Evaluation and analysis methods: The degree of hydrogenation of the product was tested using nuclear magnetic resonance spectroscopy.

[0059] The glass transition temperature was tested according to the method in GB / T 29611-2013.

[0060] The product's heat and oxygen aging resistance was compared by comparing the Shore A hardness, tensile strength, and elongation at break before and after aging. The Shore A hardness was tested according to GB / T 531.1-2008, and the tensile properties were tested according to GB / T528-2009.

[0061] The product parameters and performance tests in all embodiments and comparative examples of this invention are shown in Tables 1 and 2.

[0062] Example Example 1 First, 61.6 g of NBR solid adhesive (containing 29 wt% acrylonitrile, Mn=93000, PDI=2.6, Mooney viscosity=52) and 700 g of chlorobenzene were added to a 1 L hydrogenation reactor. The atmosphere inside the reactor was purged with nitrogen, and the mixture was stirred and dissolved at 60 °C for 6 h. Then, 8.4 g of butadiene-styrene copolymer (Mn=2080, styrene content=40 wt%) was added to the reactor. Next, 56 mg of Hoveyda-Grubbs II catalyst was added, and 10 MPa of high-purity hydrogen was introduced. The reaction was carried out at 90 °C for 3 h. The cooled hydrogenated adhesive solution was then condensed by passing it through CH3OH, and dried to obtain the product. The proton NMR spectrum of the product is shown below. Figure 1 As shown.

[0063] Example 2 First, 63 g of NBR solid adhesive (containing 29 wt% acrylonitrile, Mn=93000, PDI=2.6, Mooney viscosity=52) and 700 g of chlorobenzene were added to a 1 L hydrogenation reactor. The atmosphere inside the reactor was purged with nitrogen and stirred at 60 °C for 6 h to dissolve the adhesive. Then, 7 g of butadiene-styrene copolymer (Mn=2080, styrene content=40 wt%) was added to the reactor. Next, 35 mg of Hoveyda-Grubbs II catalyst was added and 10 MPa of high-purity hydrogen was introduced. The reaction was carried out at 90 °C for 5 h. The cooled hydrogenated adhesive solution was then condensed by passing it through CH3OH and dried to obtain the product.

[0064] Example 3 First, 64.4 g of NBR solid adhesive (containing 29 wt% acrylonitrile, Mn=93000, PDI=2.6, Mooney viscosity=52) and 700 g of chlorobenzene were added to a 1 L hydrogenation reactor. The atmosphere inside the reactor was purged with nitrogen and stirred at 60 °C for 6 h to dissolve the adhesive. Then, 5.6 g of butadiene-styrene copolymer (Mn=2080, styrene content=40 wt%) was added to the reactor. Next, 21 mg of Hoveyda-Grubbs II catalyst was added and 10 MPa of high-purity hydrogen was introduced. The reaction was carried out at 90 °C for 5 h. The cooled hydrogenated adhesive solution was then condensed by passing it through CH3OH and dried to obtain the product.

[0065] Example 4 First, 63 g of NBR solid adhesive (containing 29 wt% acrylonitrile, Mn=93000, PDI=2.6, Mooney viscosity=52) and 700 g of chlorobenzene were added to a 1 L hydrogenation reactor. The atmosphere inside the reactor was purged with nitrogen and stirred at 60 °C for 6 h to dissolve the adhesive. Then, 7 g of butadiene-styrene copolymer (Mn=2080, styrene content=40 wt%) was added to the reactor. Next, 21 mg of Hoveyda-Grubbs II catalyst was added and 10 MPa of high-purity hydrogen was introduced. The reaction was carried out at 100 °C for 6 h. The cooled hydrogenated adhesive solution was then condensed by passing it through CH3OH and dried to obtain the product.

[0066] Example 5 First, 64.4 g of NBR solid adhesive (containing 29 wt% acrylonitrile, Mn=93000, PDI=2.6, Mooney viscosity=52) and 700 g of chlorobenzene were added to a 1 L hydrogenation reactor. The atmosphere inside the reactor was purged with nitrogen and stirred at 60 °C for 6 h to dissolve the adhesive. Then, 5.6 g of butadiene-styrene copolymer (Mn=2080, styrene content=40 wt%) was added to the reactor. Next, 21 mg of Hoveyda-Grubbs II catalyst was added and 10 MPa of high-purity hydrogen was introduced. The reaction was carried out at 70 °C for 6 h. The cooled hydrogenated adhesive solution was then condensed by passing it through CH3OH and dried to obtain the product.

[0067] Example 6 First, 63 g of NBR solid adhesive (containing 29 wt% acrylonitrile, Mn=93000, PDI=2.6, Mooney viscosity=52) and 700 g of toluene were added to a 1 L hydrogenation reactor. The atmosphere inside the reactor was purged with nitrogen and stirred at 60 °C for 6 h to dissolve the adhesive. Then, 7 g of butadiene-styrene copolymer (Mn=2080, styrene content=40 wt%) was added to the reactor. Next, 35 mg of Zhan Catalyst-1B catalyst was added and 10 MPa of high-purity hydrogen was introduced. The reaction was carried out at 100 °C for 6 h. The cooled hydrogenated adhesive solution was then condensed by passing it through CH3OH and dried to obtain the product.

[0068] Example 7 First, 63 g of NBR solid adhesive (containing 29 wt% acrylonitrile, Mn=93000, PDI=2.6, Mooney viscosity=52) and 700 g of toluene were added to a 1 L hydrogenation reactor. The atmosphere inside the reactor was purged with nitrogen and stirred at 60 °C for 6 h to dissolve the adhesive. Then, 7 g of butadiene-styrene copolymer (Mn=2080, styrene content=40 wt%) was added to the reactor. Next, 21 mg of Zhan Catalyst-1B catalyst was added and 10 MPa of high-purity hydrogen was introduced. The reaction was carried out at 100 °C for 6 h. The cooled hydrogenated adhesive solution was then condensed by passing it through CH3OH and dried to obtain the product.

[0069] Example 8 First, 63 g of NBR solid adhesive (containing 33 wt% acrylonitrile, Mn=84000, PDI=2.8, Mooney viscosity=49) and 700 g of toluene were added to a 1 L hydrogenation reactor. The atmosphere inside the reactor was purged with nitrogen and stirred at 60 °C for 6 h to dissolve the adhesive. Then, 7 g of butadiene-styrene copolymer (Mn=2080, styrene content=40 wt%) was added to the reactor. Next, 56 mg of Zhan Catalyst-1B catalyst was added and 10 MPa of high-purity hydrogen was introduced. The reaction was carried out at 70 °C for 6 h. The cooled hydrogenated adhesive solution was then condensed by passing it through CH3OH and dried to obtain the product.

[0070] Example 9 First, 64.4 g of NBR solid adhesive (containing 25 wt% acrylonitrile, Mn=90000, PDI=2.6, Mooney viscosity=47) and 700 g of chlorobenzene were added to a 1 L hydrogenation reactor. The atmosphere inside the reactor was purged with nitrogen and stirred at 60 °C for 6 h to dissolve the adhesive. Then, 5.6 g of butadiene-styrene copolymer (Mn=2920, styrene content=50 wt%) was added to the reactor. Next, 35 mg of Hoveyda-Grubbs II catalyst was added and 10 MPa of high-purity hydrogen was introduced. The reaction was carried out at 90 °C for 6 h. The cooled hydrogenated adhesive solution was then condensed by passing it through CH3OH and dried to obtain the product.

[0071] Example 10 First, 61.6 g of NBR solid adhesive (containing 33 wt% acrylonitrile, Mn=84000, PDI=2.8, Mooney viscosity=49) and 700 g of chlorobenzene were added to a 1 L hydrogenation reactor. The atmosphere inside the reactor was purged with nitrogen and stirred at 60 °C for 6 h to dissolve the adhesive. Then, 8.4 g of butadiene-styrene copolymer (Mn=1750, styrene content=30 wt%) was added to the reactor. Next, 35 mg of Hoveyda-Grubbs II catalyst was added and 10 MPa of high-purity hydrogen was introduced. The reaction was carried out at 90 °C for 6 h. The cooled hydrogenated adhesive solution was then condensed by passing it through CH3OH and dried to obtain the product.

[0072] Example 11 First, 64.4 g of NBR solid adhesive (containing 33 wt% acrylonitrile, Mn=84000, PDI=2.8, Mooney viscosity=49) and 700 g of toluene were added to a 1 L hydrogenation reactor. The atmosphere inside the reactor was purged with nitrogen and stirred at 60 °C for 6 h to dissolve the adhesive. Then, 5.6 g of butadiene-styrene copolymer (Mn=2080, styrene content=40 wt%) was added to the reactor. Next, 56 mg of Grubbs II catalyst was added and 10 MPa of high-purity hydrogen was introduced. The reaction was carried out at 90 °C for 6 h. The cooled hydrogenated adhesive solution was then condensed by passing it through CH3OH and dried to obtain the product.

[0073] Example 12 First, 66.5 g of NBR solid adhesive (containing 29 wt% acrylonitrile, Mn=93000, PDI=2.6, Mooney viscosity=52) and 700 g of chlorobenzene were added to a 1 L hydrogenation reactor. The atmosphere inside the reactor was purged with nitrogen and stirred at 60 °C for 6 h to dissolve the adhesive. Then, 3.5 g of butadiene-styrene copolymer (Mn=2080, styrene content=40 wt%) was added to the reactor. Next, 56 mg of Hoveyda-Grubbs II catalyst was added and 10 MPa of high-purity hydrogen was introduced. The reaction was carried out at 90 °C for 3 h. The cooled hydrogenated adhesive solution was then condensed by passing it through CH3OH and dried to obtain the product.

[0074] Example 13 First, 61.6 g of NBR solid adhesive (containing 29 wt% acrylonitrile, Mn=93000, PDI=2.6, Mooney viscosity=52) and 700 g of chlorobenzene were added to a 1 L hydrogenation reactor. The atmosphere inside the reactor was purged with nitrogen and stirred at 60 °C for 6 h to dissolve the adhesive. Then, 8.4 g of 1,10-undecene-styrene copolymer (Mn=2620, styrene content=40 wt%) was added to the reactor. Next, 56 mg of Hoveyda-Grubbs II catalyst was added and 10 MPa of high-purity hydrogen was introduced. The reaction was carried out at 90 °C for 3 h. The cooled hydrogenated adhesive solution was then condensed by passing it through CH3OH and dried to obtain the product.

[0075] Comparative Example 1 This comparative example is the same as Example 4, except that no conjugated diene-styrene copolymer is added.

[0076] First, 70.0 g of NBR solid adhesive (containing 29 wt% acrylonitrile, Mn=93000, PDI=2.6, Mooney viscosity=52) and 700 g of chlorobenzene were added to a 1 L hydrogenation reactor. The atmosphere inside the reactor was purged with nitrogen and stirred at 60 °C for 6 h to dissolve the adhesive. Then, 21 mg of Hoveyda-Grubbs II catalyst was added to the reactor and 10 MPa of high-purity hydrogen was introduced. The reaction was carried out at 100 °C for 6 h. The cooled hydrogenated adhesive solution was then condensed by passing it through CH3OH and dried to obtain the product.

[0077] Comparative Example 2 Compared to Example 4, the added conjugated diene-styrene copolymer had a mass ratio of 1:3 to NBR in this comparative example.

[0078] First, 52.5 g of NBR solid adhesive (containing 29 wt% acrylonitrile, Mn=93000, PDI=2.6, Mooney viscosity=52) and 700 g of chlorobenzene were added to a 1 L hydrogenation reactor. The atmosphere inside the reactor was purged with nitrogen and stirred at 60 °C for 6 h to dissolve the adhesive. Then, 17.5 g of butadiene-styrene copolymer (Mn=2920, styrene content=50 wt%) was added to the reactor. Next, 21 mg of Hoveyda-Grubbs II catalyst was added to the reactor and 10 MPa of high-purity hydrogen was introduced. The reaction was carried out at 100 °C for 6 h. The cooled hydrogenated adhesive solution was then condensed by passing it through CH3OH and dried to obtain the product.

[0079] Table 1

[0080] Test case The Shore A hardness, tensile strength, and elongation at break of the samples obtained in the test examples and Comparative Example 1 were then tested. Next, thermo-oxidative aging performance tests were conducted: the three samples were placed in a forced-ventilation thermo-aging chamber with an air exchange rate of 50 times / h, a temperature controlled at 150 ℃, and an aging time of 70 h. After the test, the samples were tested again for Shore A hardness, tensile strength, and elongation at break, and the changes in performance values ​​before and after aging were compared. The results are shown in Table 2.

[0081] Table 2 Example Shore A hardness variation (degrees) Tensile strength change rate (%) Change in elongation at break (%) Example 1 +7 -3.58 -12.89 Example 2 +7 -3.88 -16.38 Example 3 +7 -6.67 -24.73 Example 4 +7 -4.75 -21.79 Example 5 +7 -4.88 -23.36 Example 6 +7 -3.91 -15.16 Example 7 +7 -6.4 -24.22 Example 8 +7 -5.22 -19.68 Example 9 +7 -4.99 -17.34 Example 10 +7 -6.2 -23.4 Example 11 +7 -5.54 -18.65 Example 12 +7 -6.91 -25.87 Example 13 +7 -7.02 -26.33 Comparative Example 1 +7 -7.61 -35.5 Comparative Example 2 has lost the basic properties of rubber.

[0082] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A modified hydrogenated nitrile butadiene rubber, characterized in that, The modified hydrogenated nitrile butadiene rubber contains grafting groups derived from hydrogenated conjugated diene-styrene copolymers; wherein, based on the mass of the modified hydrogenated nitrile butadiene rubber, the grafting rate of the modified hydrogenated nitrile butadiene rubber is 5wt%-20wt%.

2. The modified hydrogenated nitrile butadiene rubber according to claim 1, characterized in that, Based on the mass of the modified hydrogenated nitrile butadiene rubber, the grafting rate of the modified hydrogenated nitrile butadiene rubber is 8wt%-12wt%; and / or The hydrogenated conjugated diene segments in the hydrogenated conjugated diene-styrene copolymer are selected from C4-C8 hydrogenated conjugated diene segments.

3. The modified hydrogenated nitrile butadiene rubber according to claim 2, characterized in that, Based on the mass of the modified hydrogenated nitrile butadiene rubber, the styrene segment content in the modified hydrogenated nitrile butadiene rubber is ≤5 wt%; and / or Based on the mass of the modified hydrogenated nitrile butadiene rubber, the bound acrylonitrile content of the modified hydrogenated nitrile butadiene rubber is 22wt%-31wt%; and / or The hydrogenated conjugated diene segment is selected from hydrogenated isoprene segments and / or hydrogenated butadiene segments.

4. The modified hydrogenated nitrile butadiene rubber according to claim 1, characterized in that, The degree of hydrogenation of the modified hydrogenated nitrile rubber is 88 wt%-100 wt%.

5. The modified hydrogenated nitrile butadiene rubber according to claim 1, characterized in that, The modified hydrogenated nitrile butadiene rubber has a glass transition temperature of -26 to -35 °C; and / or The modified hydrogenated nitrile butadiene rubber has a number average molecular weight of 33,000-76,000; and / or The modified hydrogenated nitrile rubber has a molecular weight distribution index of 1.8-4.

7.

6. A method for preparing modified hydrogenated nitrile butadiene rubber, characterized in that, The method includes: In the presence of solvent, hydrogen, and catalyst, nitrile rubber undergoes a contact reaction with conjugated diene-styrene copolymer, including cross-metathesis and hydrogenation.

7. The method according to claim 6, characterized in that, The conjugated diene segments in the conjugated diene-styrene copolymer are selected from C4-C8 conjugated diene segments; and / or The content of the conjugated diene segment in the conjugated diene-styrene copolymer is 50 wt%-80 wt%; and / or The styrene segment content in the conjugated diene-styrene copolymer is 20 wt%-50 wt%.

8. The method according to claim 7, characterized in that, The conjugated diene segment is selected from isoprene segments and / or butadiene segments; and / or The number-average molecular weight of the conjugated diene-styrene copolymer is 1000-3000.

9. The method according to claim 6, characterized in that, The nitrile rubber has a bound acrylonitrile content of 25 wt%-35 wt%; and / or The number average molecular weight of the nitrile rubber is 60,000-130,000; and / or The molecular weight distribution index of the nitrile rubber is 1.5-3; and / or The Mooney viscosity of the nitrile rubber is 45-55.

10. The method according to claim 6, characterized in that, The catalyst is at least one of Grubbs II, Grubbs III, Hoveyda-Grubbs II, and Zhan Catalyst-1B; and / or The solvent is selected from at least one of methyl ethyl ketone, toluene, butanone, chloroform, trichloromethane, ethyl acetate, butyl butyrate, chlorobenzene, stilbene, toluene, and xylene.

11. The method according to claim 6, characterized in that, The mass ratio of the catalyst to nitrile rubber is 0.0002-0.0015:1; and / or The mass ratio of the nitrile rubber to the solvent is 0.088-0.095:1; and / or The mass ratio of the conjugated diene-styrene copolymer to the solvent is 0.005-0.012:

1.

12. The method according to claim 6, characterized in that, The pressure of the hydrogen gas is 6-12 MPa; and / or The conditions for the contact reaction include: a temperature of 70-160 °C; and / or a time of 1-12 h.

13. The method according to claim 6, characterized in that, The method also includes coagulation after the contact reaction; the coagulant used for coagulation is selected from alcohol solvents or water.

14. A modified hydrogenated nitrile butadiene rubber prepared by the preparation method according to any one of claims 6-13.

Images