A dynamically cross-linked styrene-butadiene rubber, and a preparation method and application thereof

Abstract

The application provides a dynamic cross-linking type butadiene styrene rubber and a preparation method and application thereof, and belongs to the technical field of polymer materials. The material is prepared from raw materials including sulfur vulcanized butadiene styrene rubber, solution polymerized butadiene styrene rubber, a tetrazine click reagent and a bicyclononane cross-linking agent. The preparation method is as follows: the sulfur vulcanized butadiene styrene rubber is mixed with the solution polymerized butadiene styrene rubber, then the tetrazine click reagent is added and mixed, and then heated to react to obtain modified butadiene styrene rubber; then the modified butadiene styrene rubber is mixed with the bicyclononane cross-linking agent, and finally hot-pressed to form the material. The dynamic cross-linking type butadiene styrene rubber exhibits mechanical properties far superior to those of traditional sulfur vulcanized butadiene styrene rubber, and provides a new way for high-value recycling of rubber.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to a dynamically cross-linked styrene-butadiene rubber, its preparation method, and its application. Background Technology

[0002] Styrene-butadiene rubber (SBR), my country's largest general-purpose rubber product, is widely used in industrial products such as tires, conveyor belts, and shock-absorbing pads. However, uncured SBR has poor mechanical properties and usually requires sulfur vulcanization to improve its mechanical properties. But the molecular chains of vulcanized SBR are permanently cross-linked, making it difficult for vulcanized SBR to self-repair after being damaged during use, and also difficult to recycle and reuse.

[0003] With the continuous growth in the consumption of styrene-butadiene rubber (SBR) products, the annual output of waste SBR has reached millions of tons, causing serious resource waste and environmental burden. Currently, the main methods for treating waste rubber are incineration and landfilling. These methods are not only energy-intensive but also release large amounts of volatile organic compounds, exacerbating environmental pollution. While mechanically crushing waste rubber and using it as a filler or modifier can achieve a certain degree of recycling, it often damages the polymer's molecular chain structure, leading to a significant decline in the performance of the resulting materials.

[0004] To address the aforementioned issues, researchers have conducted studies to achieve the recyclability and reprocessing of styrene-butadiene rubber (SBR) and obtain high-strength, high-toughness materials. For example, the literature (DOI: 10.1021 / acs.iecr.0c05249) discloses a high-strength SBR composite material based on copper-nitrogen coordination and its preparation method. This technology uses solution-polymerized SBR as the matrix, grafting 3,6-bis(2-pyridyl)-1,2,4,5-tetraazine onto the rubber molecular chain via a reverse electron-demanding Diels-Alder click reaction, and using copper sulfate as a crosslinking agent to form reversible Cu-N coordination crosslinking bonds with the grafted tetraazine groups. However, this technical approach has the following drawbacks: when increasing the crosslinking density to improve tensile strength, the elongation at break of the material decreases significantly; conversely, to ensure a high elongation at break, ideal tensile strength cannot be obtained. This means that there is a clear inverse relationship between the tensile strength and elongation at break of the material, making it difficult to simultaneously achieve these two key mechanical properties, which limits its application in the field of high-performance recycled rubber materials.

[0005] Therefore, for the high-value recycling of sulfur-cured styrene-butadiene rubber (SBR), there is still a lack of effective technical solutions for simultaneously achieving excellent tensile strength and elongation at break during the recycling process. Developing a new method that can balance the high mechanical properties of waste SBR with good ductility is of great significance for promoting the green and sustainable development of the rubber industry. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a CN-based... + This paper describes a dynamically interface-based recycled styrene-butadiene rubber (SBR) material, its preparation method, and its applications. The mechanical properties of this material can be adjusted over a wide range based on the ratio of sulfur-cured SBR to solution-polymerized SBR. Its mechanical strength far exceeds that of traditional sulfur-cured rubber, meeting the requirements for practical applications.

[0007] To achieve the above objectives, the present invention employs a technical solution consisting of the following technical measures.

[0008] This invention provides a dynamically crosslinked styrene-butadiene rubber, which is prepared from the following raw materials in parts by weight: 10-90 parts of sulfur-cured styrene-butadiene rubber, 10-90 parts of solution-polymerized styrene-butadiene rubber, 1-15 parts of tetrazine click reagent, and 1-20 parts of bicyclononane crosslinking agent.

[0009] Furthermore, it is prepared from the following raw materials in parts by weight: 60-80 parts of sulfur-cured styrene-butadiene rubber, 20-40 parts of solution-polymerized styrene-butadiene rubber, 3-8 parts of tetrazine click reagent, and 5-9 parts of bicyclononane crosslinking agent.

[0010] Furthermore, the sulfur-cured styrene-butadiene rubber is prepared from the following raw materials in parts by weight: 100 parts solution-polymerized styrene-butadiene rubber, 3-10 parts vulcanizing activator, 0.5-5 parts vulcanizing agent, 0.5-3 parts accelerator, and 0.5-3 parts antioxidant.

[0011] Further, the sulfur-cured styrene-butadiene rubber is prepared from the following raw materials in parts by weight: 100 parts solution-polymerized styrene-butadiene rubber, 7-8 parts vulcanizing activator, 0.8-1.5 parts vulcanizing agent, 1.5-2.5 parts accelerator, and 0.8-1.5 parts antioxidant, preferably: 100 parts solution-polymerized styrene-butadiene rubber, 5 parts vulcanizing activator, 1 part vulcanizing agent, 2 parts accelerator, and 1 part antioxidant.

[0012] Preferably, the vulcanizing activator is zinc oxide and stearic acid; the vulcanizing agent is sulfur; the accelerator is a sulfenamide accelerator, preferably N-cyclohexyl-2-benzothiazole sulfenamide (CZ); and the antioxidant is an amine antioxidant, preferably N-cyclohexyl-N'-phenyl-p-phenylenediamine (antioxidant 4010).

[0013] Further, the preparation method of the sulfur-cured styrene-butadiene rubber includes the following steps: 100 g of solution-polymerized styrene-butadiene rubber (SSBR), 5 g of zinc oxide, 1 g of stearic acid, 2 g of sulfur, 1 g of N-cyclohexyl-2-benzothiazole sulfenamide (CZ) and 1 g of antioxidant 4010 (N-cyclohexyl-N'-phenyl-p-phenylenediamine) are mixed evenly on a two-roll mill, and then hot-pressed for 20 minutes at 143 °C and 10 MPa using a flat vulcanizing machine to obtain the conventional sulfur-cured rubber SSBR-S.

[0014] Furthermore, in the solution-polymerized styrene-butadiene rubber: the mass fraction of 1,2-butadiene units is 40%~60%, the mass fraction of 1,4-butadiene units is 20%~40%, and the mass fraction of styrene units is 10%~30%.

[0015] Preferably, in the solution-polymerized styrene-butadiene rubber: the mass fraction of 1,2-butadiene units is 54%, the mass fraction of 1,4-butadiene units is 27%, and the mass fraction of styrene units is 19%.

[0016] Further, the tetrazine click reagent is selected from at least one of 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine, 3,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)-1,2,4,5-tetrazine, and 3,6-bis(pyridin-4-yl)-1,2,4,5-tetrazine.

[0017] Furthermore, the tetrazine click reagent is 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine.

[0018] Further, the bicyclic nonane crosslinking agent is selected from at least one of 2,6-dichloro-9-selenobicyclo[3.3.1]nonane, 2,6-dichloro-9-thiobicyclo[3.3.1]nonane, and 2,6-dichloro-9-phenylaminobicyclo[3.3.1]nonane.

[0019] Furthermore, the bicyclic nonane crosslinking agent is 2,6-dichloro-9-selenobicyclo[3.3.1]nonane.

[0020] The present invention also provides a method for preparing the above-mentioned dynamically crosslinked styrene-butadiene rubber, the method comprising the following steps: mixing sulfur-cured styrene-butadiene rubber, solution-polymerized styrene-butadiene rubber, tetrazine click reagent and bicyclononane crosslinking agent, molding, to obtain dynamically crosslinked styrene-butadiene rubber.

[0021] Furthermore, the method includes the following steps:

[0022] (1) Sulfur-cured styrene-butadiene rubber and solution-polymerized styrene-butadiene rubber are mixed to obtain a blend;

[0023] (2) The blend is mixed with a tetrazine click reagent to obtain a mixture;

[0024] (3) The mixture is heated to react and modified styrene-butadiene rubber is obtained;

[0025] (4) The modified styrene-butadiene rubber is mixed with a dicyclononane crosslinking agent to obtain a styrene-butadiene rubber mixture;

[0026] (5) The styrene-butadiene rubber mixture is molded to obtain dynamically cross-linked styrene-butadiene rubber.

[0027] Further, in steps (1), (2) and (4), the mixing temperature is 15~25℃; in step (3), the heating reaction temperature is 140~160℃ and the time is 3~10min; in step (5), the molding is hot pressing molding, the hot pressing molding temperature is 140~150℃ and the time is 3~30min.

[0028] Further, in step (3), the heating reaction temperature is 150°C and the time is 5 min; in step (5), the hot pressing temperature is 143°C and the time is 20 min.

[0029] The present invention also provides the use of the above-mentioned dynamically cross-linked styrene-butadiene rubber in the preparation of tire, conveyor belt, shock absorber, seal or hose material.

[0030] Compared with the prior art, the technical solution provided by the present invention can produce the following beneficial technical effects:

[0031] (1) The mechanical properties are significantly better than those of traditional sulfur-cured styrene-butadiene rubber: The tensile strength of the recycled styrene-butadiene rubber prepared by this invention can reach 20~30 MPa and the elongation at break can reach 400%~700%, which are significantly better than those of traditional sulfur-cured styrene-butadiene rubber (the tensile strength is usually 2~5 MPa and the elongation at break is usually 200%~500%), realizing the high-value recycling of waste rubber.

[0032] (2) Simultaneously achieving high tensile strength and high elongation at break: Compared with the high-strength styrene-butadiene rubber composite material based on copper-nitrogen coordination disclosed in the literature (DOI: 10.1021 / acs.iecr.0c05249), the modified material in that literature has a tensile strength of 1.93~12.83 MPa and an elongation at break of 550%~998%, but there is a clear contradiction between strength and toughness—when the tensile strength reaches the maximum of 12.83 MPa, the elongation at break is only 550%; while when the elongation at break reaches the maximum of 998%, the tensile strength is only 1.93 MPa. This invention successfully solved this technical contradiction by optimizing the ratio of tetrazine click reagent to bicyclononane crosslinking agent, as well as the ratio of waste rubber to fresh rubber, and maintained high tensile strength (27.41 MPa) while still having excellent elongation at break (681.03%).

[0033] (3) Mechanical properties can be precisely controlled within a wide range: The mechanical strength of the present invention can be adjusted within a wide range by adjusting the amount of sulfur-cured styrene-butadiene rubber and solution-polymerized styrene-butadiene rubber.

[0034] Obviously, based on the above description of the present invention, and according to common technical knowledge and conventional methods in the field, various other modifications, substitutions or alterations can be made without departing from the basic technical concept of the present invention.

[0035] The following detailed embodiments further illustrate the above-described content of the present invention. However, this should not be construed as limiting the scope of the present invention to the following embodiments. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention. Attached Figure Description

[0036] Figure 1 This is a molded sample.

[0037] Figure 2 The vulcanization curve of the blend vulcanization system (T-SSBR-SeBCN) of sulfur-cured styrene-butadiene rubber (T-SSBR) modified with tetrazine click reagent and bicyclononane crosslinking agent (SeBCN).

[0038] Figure 3 This is a comparison chart of the mechanical properties of dynamically cross-linked styrene-butadiene rubber materials. Detailed Implementation

[0039] To better explain the present invention, the main contents of the invention are further illustrated below with reference to specific embodiments, but the content of the present invention is not limited to the following embodiments. Unless otherwise specified, the raw materials and equipment used in the present invention are all known products, obtained by purchasing commercially available products.

[0040] In this embodiment of the invention, the sulfur-cured styrene-butadiene rubber (i.e., traditional sulfur-cured rubber, abbreviated as SSBR-S) is prepared according to national standards. The specific preparation method is as follows: 100 g of solution-polymerized styrene-butadiene rubber (SSBR), 5 g of zinc oxide, 1 g of stearic acid, 2 g of sulfur, 1 g of N-cyclohexyl-2-benzothiazole sulfenamide (CZ) and 1 g of antioxidant 4010 (N-cyclohexyl-N'-phenyl-p-phenylenediamine) are mixed evenly on a two-roll mill, and then hot-pressed for 20 minutes at 143 ℃ and 10 MPa using a flat vulcanizing machine to obtain traditional sulfur-cured rubber SSBR-S.

[0041] In this embodiment of the invention, the solution-polymerized styrene-butadiene rubber contains: 54% by mass of 1,2-butadiene units, 27% by mass of 1,4-butadiene units, and 19% by mass of styrene units. The solution-polymerized styrene-butadiene rubber is grade SBR2466 and was purchased from Lanzhou Petrochemical Company of China National Petroleum Corporation.

[0042] Example 1: Dynamically cross-linked styrene-butadiene rubber material

[0043] Raw material composition (by weight):

[0044]

[0045] The preparation method includes the following steps:

[0046] (1) Under normal temperature (15~25℃) conditions, sulfur-cured styrene-butadiene rubber and solution-polymerized styrene-butadiene rubber are mixed evenly on a two-roll mill and set aside.

[0047] (2) Under normal temperature (15~25℃) conditions, the blend obtained in step (1) is mixed with the tetrazine click reagent on a two-roll mill until uniform, and set aside for later use;

[0048] (3) React the mixture obtained in step (2) in an oven at 150°C for 5 min to obtain modified styrene-butadiene rubber for later use;

[0049] (4) Under normal temperature (15~25℃) conditions, the modified styrene-butadiene rubber obtained in step (3) is mixed evenly with dicyclononane crosslinking agent on a two-roll mill and set aside.

[0050] (5) The styrene-butadiene rubber mixture obtained in step (4) is hot-pressed at 143°C for 20 min on a flat vulcanizing machine to obtain a dynamically cross-linked styrene-butadiene rubber material (denoted as T5SSBR-T5SBR-20%-5phr).

[0051] Example 2: Dynamically cross-linked styrene-butadiene rubber material

[0052] Raw material composition (by weight):

[0053]

[0054] Preparation method: Same as in Example 1, to obtain a dynamically cross-linked styrene-butadiene rubber material (denoted as T5SSBR-T5SBR-30%-5phr).

[0055] Example 3: Dynamically cross-linked styrene-butadiene rubber material

[0056] Raw material composition (by weight):

[0057]

[0058] Preparation method: Same as in Example 1, to obtain dynamically cross-linked styrene-butadiene rubber material (denoted as T5SSBR-T5SBR-40%-5phr).

[0059] Example 4: Dynamically cross-linked styrene-butadiene rubber material

[0060] Raw material composition (by weight):

[0061]

[0062] Preparation method: Same as in Example 1, to obtain dynamically cross-linked styrene-butadiene rubber material (denoted as T5SSBR-T5SBR-40%-7phr).

[0063] Example 5: Dynamically cross-linked styrene-butadiene rubber material

[0064] Raw material composition (by weight):

[0065]

[0066] Preparation method: Same as in Example 1, to obtain dynamically cross-linked styrene-butadiene rubber material (denoted as T5SSBR-T5SBR-40%-9phr).

[0067] The following experimental examples demonstrate the beneficial effects of the present invention.

[0068] Experimental Example 1: Characterization and Mechanical Property Testing of Dynamically Crosslinked Styrene-Butadiene Rubber Materials

[0069] 1. Experimental Methods

[0070] (1) Mechanical property testing method: The uniaxial tensile test of the material was carried out on an Instron-5967 in the United States at a tensile speed of 100 mm / min. The test specimen was dumbbell-shaped with a neck size of 20×2×1 mm3. At least 3 parallel specimens were tested for each sample.

[0071] (2) Vulcanization characteristic test method: The vulcanization characteristics of the material in Example 1 were tested on a rubber processing analyzer. The test temperature was 143℃ and the test time was 30 minutes.

[0072] 2. Experimental Results

[0073] Figure 1 Photographs of the molded samples of the dynamically cross-linked styrene-butadiene rubber material prepared.

[0074] Figure 2 This is a vulcanization curve diagram of styrene-butadiene rubber (SBR) blended with dicyclononane. The vulcanization curve shows the optimal vulcanization time (t) for this system. 90 The reaction takes about 5 minutes. Hot pressing at 143℃ for 15 minutes can ensure complete cross-linking. At this time, the torque is stable at about 3.4dNm, and there is no obvious reversion phenomenon.

[0075] Table 1. Test results of mechanical properties of dynamically cross-linked styrene-butadiene rubber materials

[0076]

[0077] Table 1 and Figure 3 Data shows that the dynamically cross-linked styrene-butadiene rubber materials prepared in Examples 1-3 of this invention exhibit significantly improved tensile strength and elongation at break compared to traditional sulfur-cured styrene-butadiene rubber. Furthermore, they simultaneously achieve excellent tensile strength and elongation at break, overcoming the technical bottleneck of the inability to simultaneously achieve both tensile strength and elongation at break in existing technologies.

[0078] In summary, this invention provides a dynamically crosslinked styrene-butadiene rubber (SBR), its preparation method, and its applications. This material is prepared from raw materials comprising sulfur-cured SBR, solution-polymerized SBR, a tetrazine click reagent, and a bicyclononane crosslinking agent. The preparation method is as follows: first, sulfur-cured SBR and solution-polymerized SBR are mixed; then, a tetrazine click reagent is added, and the mixture is heated to react, yielding modified SBR; then, the modified SBR is mixed with a bicyclononane crosslinking agent, and finally, the mixture is hot-pressed to obtain the material. This dynamically crosslinked SBR exhibits mechanical properties far superior to traditional sulfur-cured SBR, providing a new approach for the high-value recycling of rubber.

Claims

1. A dynamically crosslinked styrene-butadiene rubber, characterized in that, It is prepared from the following raw materials in parts by weight: 10-90 parts sulfur-cured styrene-butadiene rubber, 10-90 parts solution-polymerized styrene-butadiene rubber, 1-15 parts tetrazine click reagent, and 1-20 parts bicyclononane crosslinking agent. The tetrazine click reagent is selected from at least one of 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine, 3,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)-1,2,4,5-tetrazine, and 3,6-bis(pyridyl-4-yl)-1,2,4,5-tetrazine; The bicyclic nonane crosslinking agent is selected from at least one of 2,6-dichloro-9-selenobicyclo[3.3.1]nonane and 2,6-dichloro-9-thiobicyclo[3.3.1]nonane.

2. The dynamically crosslinked styrene-butadiene rubber according to claim 1, characterized in that, It is prepared from the following raw materials in parts by weight: 60-80 parts sulfur-cured styrene-butadiene rubber, 20-40 parts solution-polymerized styrene-butadiene rubber, 3-8 parts tetrazine click reagent, and 5-9 parts bicyclononane crosslinking agent.

3. The dynamically crosslinked styrene-butadiene rubber according to claim 1, characterized in that, The tetrazine click reagent is 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine.

4. The dynamically crosslinked styrene-butadiene rubber according to claim 1, characterized in that, The bicyclic nonane crosslinking agent is 2,6-dichloro-9-selenobicyclo[3.3.1]nonane.

5. A method for preparing the dynamically crosslinked styrene-butadiene rubber according to any one of claims 1 to 4, characterized in that, The method includes the following steps: mixing sulfur-cured styrene-butadiene rubber, solution-polymerized styrene-butadiene rubber, tetrazine click reagent and bicyclononane crosslinking agent, molding, to obtain dynamically crosslinked styrene-butadiene rubber.

6. The preparation method according to claim 5, characterized in that, The method includes the following steps: (1) Sulfur-cured styrene-butadiene rubber and solution-polymerized styrene-butadiene rubber are mixed to obtain a blend; (2) The blend is mixed with a tetrazine click reagent to obtain a mixture; (3) The mixture is heated to react and modified styrene-butadiene rubber is obtained; (4) The modified styrene-butadiene rubber is mixed with a dicyclononane crosslinking agent to obtain a styrene-butadiene rubber mixture; (5) The styrene-butadiene rubber mixture is molded to obtain dynamically cross-linked styrene-butadiene rubber.

7. The preparation method according to claim 6, characterized in that, In steps (1), (2) and (4), the mixing temperature is 15~25℃; in step (3), the heating reaction temperature is 140~160℃ and the time is 3~10min; in step (5), the molding is hot pressing molding, the hot pressing molding temperature is 140~150℃ and the time is 3~30min.

8. Use of the dynamically cross-linked styrene-butadiene rubber according to any one of claims 1 to 4 in the preparation of tire, conveyor belt, shock absorber, seal or hose material.

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