Solid-phase reclaimed rubber, method for preparing the same, and use thereof
By introducing specific diazo compounds or anti-vulcanization copolymers into waste rubber as interface modifiers, solid-phase regenerated rubber is prepared, solving the problems of performance degradation and phase separation in waste rubber recycling. This results in regenerated rubber with high strength and high fatigue threshold, suitable for tire and bridge engineering materials.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HAINAN UNIV
- Filing Date
- 2024-07-24
- Publication Date
- 2026-05-12
AI Technical Summary
Existing waste rubber recycling technologies suffer from problems such as performance degradation, pollution, and high energy consumption. Furthermore, when waste rubber is used as a filler and blended with virgin rubber, phase separation occurs, leading to a decline in the performance of composite materials.
采用特定的重氮化合物或逆硫化共聚物作为界面改性剂，在特定条件下与废旧橡胶和原生橡胶混合，通过热压硫化制备固相再生橡胶，提高其拉伸强度和疲劳阈值。
It significantly improves the tensile strength and fatigue threshold of solid-phase recycled rubber, provides a high-value recycling pathway for waste rubber, and enhances the performance of composite materials.
Smart Images
Figure CN118909335B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of waste rubber recycling technology, and in particular to a solid-phase regenerated rubber, its preparation method, and its application. Background Technology
[0002] Rubber, due to its unique high elasticity, is widely used in aerospace, defense, tires, medical elastomers, and other fields, playing a vital role in national economic development. However, such widespread use has also brought enormous recycling pressure. Currently, approximately 4 billion waste tires are discarded or left idle worldwide. The global recycling of waste rubber has a significant impact on the environment, energy, and climate, creating "black pollution," which is even more difficult to manage than "white pollution."
[0003] Currently, the main method for recycling waste rubber is "downgrading," such as mechanically breaking it down and reusing it as a low-value material. Producing reclaimed rubber is the primary way to achieve high-value recycling of waste rubber; however, desulfurization and regeneration technologies inevitably lead to the breakage of the rubber molecular chain, reducing the performance of the reclaimed rubber and causing drawbacks such as high pollution and high energy consumption. Furthermore, due to the inability to further process the sulfur vulcanization network, blending waste rubber as a filler with virgin rubber or other matrices can result in phase separation, significantly degrading the performance of the composite material. Summary of the Invention
[0004] In view of this, embodiments of this application provide a solid-phase reclaimed rubber, its preparation method and application, which has better tensile strength and can effectively overcome the defects of the prior art.
[0005] The first aspect of this application provides a solid-phase recycled rubber, comprising the following raw materials calculated by weight: 1-100 parts of waste rubber and 0.1-20 parts of diazo compound / reverse vulcanization copolymer.
[0006] In some embodiments that may include the above embodiments, the preparation raw materials include the following by weight: 100 parts of virgin rubber, 0.1-20 parts of anti-vulcanization copolymer, 1-10 parts of zinc oxide, 1-5 parts of stearic acid, 1-5 parts of accelerator, 0.1-6 parts of sulfur, and 1-60 parts of waste rubber.
[0007] In some embodiments that may include the above embodiments, the preparation raw materials include the following parts by weight: 100 parts of virgin rubber, 0.1-20 parts of diazo compound, and 1-60 parts of waste rubber.
[0008] In some embodiments that may include the above embodiments, the reverse vulcanizing copolymer is at least one of hydroxyl-based reverse vulcanizing copolymers, thioctic acid-based reverse vulcanizing copolymers, and carboxyl-based reverse vulcanizing copolymers.
[0009] In some embodiments that may include the above embodiments, the diazo compound is a diazo compound containing dynamic disulfide bonds or covalent bonds.
[0010] In some embodiments that may include the above embodiments, the virgin rubber is natural rubber or synthetic rubber; or
[0011] The virgin rubber is at least one of isoprene rubber, styrene-butadiene rubber, cis-butadiene rubber, nitrile rubber, butyl rubber, ethylene propylene rubber, and chloroprene rubber; or
[0012] The waste rubber is factory-grade waste rubber.
[0013] A second aspect of this application also provides a method for preparing the above-mentioned solid-phase reclaimed rubber, comprising the following steps:
[0014] S1. Preparation of diazo compound: 2-hydroxyethyl disulfide (preferably bis(2-hydroxyethyl) disulfide) / ethylene glycol, pyridine, and phenylacetyl chloride are dissolved in dichloromethane and reacted at room temperature for 1-12 h. After purification, the first step product is obtained. The first step product, toluenesulfonyl azide, and 1,8-diazabicyclo[5.4.0]undec-7-ene are dissolved in dichloromethane and reacted at room temperature for 1-12 h. After purification, the diazo compound is obtained.
[0015] S2. Preparation of solid-phase reclaimed rubber: The diazo compound is mixed with waste rubber or the diazo compound, virgin rubber and waste rubber are mixed and hot-pressed at 100-145℃ for 15-30 min and at 10-15 MPa to obtain solid-phase reclaimed rubber.
[0016] In some embodiments that may include the above embodiments, in step S1, the molar ratio of 2-hydroxyethyl disulfide / ethylene glycol, pyridine and phenylacetyl chloride is 1:(0.5-6):(0.5-6); the molar ratio of the first step product, toluenesulfonyl azide and 1,8-diazabicyclo[5.4.0]undec-7-ene is 1:(0.5-6):(0.5-6).
[0017] A third aspect of this application also provides a method for preparing the above-mentioned solid-phase reclaimed rubber, comprising the following steps:
[0018] S1. Preparation of anti-vulcanization copolymer: Mix sulfur, monomer and accelerator, and react at 130-160℃ for 3-8 hours to obtain anti-vulcanization copolymer;
[0019] Preferably, in step S1, the mass ratio of sulfur, monomer, and accelerator is (0.5-5):1:(0.1-1); preferably, the monomer is at least one of Span80, lipoic acid, lipoic acid derivatives, and undecenol.
[0020] S2. Preparation of solid-phase reclaimed rubber: The reverse vulcanization copolymer, virgin rubber, zinc oxide, stearic acid, accelerator, sulfur, and waste rubber are mixed, or the reverse vulcanization copolymer and waste rubber are mixed, and hot-pressed vulcanization is carried out at 100-145℃ for 15-30 min and at 10-15 MPa to obtain solid-phase reclaimed rubber.
[0021] The fourth aspect of this application also provides the application of the above-described solid-phase recycled rubber in the preparation of gaskets, rubber blends, or equipment for tire / bridge engineering materials.
[0022] Compared with the prior art, the embodiments of this application have the following beneficial effects:
[0023] This application utilizes specific compounds or polymers with CH bond functionalization as interface modifiers, which, under specific accelerators, can significantly improve the tensile strength and fatigue threshold of solid-phase reclaimed rubber, providing a new means for the upgrading and recycling of waste rubber and showing good application prospects. Attached Figure Description
[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0025] Figure 1 The stress-strain curve of the solid-phase recycled rubber in Example 1 of this application;
[0026] Figure 2 This is the relationship curve between the crack propagation rate and G of the solid-phase reclaimed rubber in Example 5 of this application. Detailed Implementation
[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0028] Unless otherwise specified, the experimental methods used in the embodiments of this application are all conventional methods.
[0029] In the following examples and comparative examples, unless otherwise specified, all raw materials can be obtained by commercial purchase or conventional methods.
[0030] Example 1
[0031] The method for preparing solid-phase recycled rubber in this embodiment includes the following steps:
[0032] 9.255 g of ethylene glycol and 10.441 g of pyridine were dissolved in dichloromethane, and 20.406 g of phenylacetyl chloride was added dropwise. The mixture was stirred at room temperature for 12 h, and the product was purified to obtain the first step product. 1 g of the first step product, 4.01 g of TsN3 (toluenesulfonyl azide), and 4.01 g of DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) were stirred at room temperature for 12 h, and the mixture was purified to obtain a diazo compound.
[0033] 0.48 parts of bis-diazo compound (BD) and 24 parts of waste rubber powder (i.e., powdered waste rubber) (80 mesh) were mixed in dichloromethane. The solvent was removed by rotary evaporation, so that the bis-diazo compound coated the surface of the waste rubber powder. The mixture was then hot-pressed and vulcanized at 145°C for 30 minutes at a vulcanization pressure of 15 MPa to obtain solid-phase reclaimed rubber (sheet).
[0034] The prepared sheet was cut into dumbbell-shaped specimens according to GB / T 528-2009, and the stress-strain curves were obtained using a high-speed rail AI-3000 tensile testing machine. Figure 1 The tensile strength of the sheet was found to be 2 MPa.
[0035] Tensile strength is the stress at which the specimen breaks.
[0036] Example 2
[0037] The method for preparing solid-phase recycled rubber in this embodiment includes the following steps:
[0038] 9.255 g of 2-hydroxyethyl disulfide and 10.441 g of pyridine were dissolved in dichloromethane, and 20.406 g of phenylacetyl chloride was added dropwise. The mixture was stirred at room temperature for 12 h, and the product was purified to obtain the first product. 1 g of the first product, 4.01 g of TsN3, and 4.01 g of DBU were stirred at room temperature for 12 h, and the mixture was purified to obtain a disulfide-containing diazo compound.
[0039] 0.48 parts of bis-diazo compounds with disulfide bonds (BDS) and 24 parts of waste rubber powder (i.e., powdered waste rubber) (80 mesh) were mixed in dichloromethane. The solvent was removed by rotary evaporation, so that the bis-diazo compounds coated the surface of the waste rubber powder. The mixture was then hot-pressed and vulcanized at 145°C for 30 minutes at a vulcanization pressure of 15 MPa to obtain solid-phase reclaimed rubber (sheet).
[0040] The tensile strength of the sheet was tested according to the method described in Example 1, and the tensile strength of the sheet was found to be 2.5 MPa.
[0041] The obtained sheet was cut into smaller pieces and then hot-pressed and vulcanized again at 145°C for 20 minutes at a vulcanization pressure of 15 MPa to obtain the reprocessed sheet. Its tensile strength was then tested again according to the method described in Example 1, and the tensile strength of the sheet was 1.7 MPa.
[0042] Example 3
[0043] The method for preparing solid-phase recycled rubber in this embodiment includes the following steps:
[0044] Add 45g of sulfur to a three-necked flask, heat to 160℃, maintain for 5 min, then add 45g of Span80 and 0.9g of accelerator ZDC, react for 3-4 h to obtain Span80 anti-vulcanization copolymer;
[0045] 1.2 parts of Span80 reverse vulcanization copolymer and 24 parts of waste rubber powder (i.e., powdered waste rubber) (80 mesh) were mixed and dissolved in tetrahydrofuran. The solvent was removed by rotary evaporation, so that the reverse vulcanization copolymer coated the surface of the waste rubber powder (i.e., powdered waste rubber). Hot pressing was carried out at 145°C for 30 minutes and at a vulcanization pressure of 15 MPa to finally obtain solid phase reclaimed rubber (sheet).
[0046] The tensile strength of the sheet was tested according to the method described in Example 1, and the tensile strength of the sheet was found to be 4.5 MPa.
[0047] Example 4
[0048] The method for preparing solid-phase recycled rubber in this embodiment includes the following steps:
[0049] Add 70g of sulfur to a three-necked flask, heat to 150℃, maintain for 5min, then add 30g of lipoic acid and 3g of N-methylimidazole accelerator, react for 8h to obtain lipoic acid anti-vulcanization copolymer.
[0050] 0.48 parts of thioctic acid reverse vulcanization copolymer and 24 parts of waste rubber powder (i.e., powdered waste rubber) (80 mesh) were mixed in tetrahydrofuran. The solvent was removed by rotary evaporation, so that the reverse vulcanization copolymer coated the surface of the waste rubber powder (i.e., powdered waste rubber). Hot pressing was carried out at 145°C for 30 min and at a vulcanization pressure of 15 MPa to finally obtain solid phase reclaimed rubber (sheet).
[0051] The tensile strength of the sheet was tested according to the method described in Example 1, and the tensile strength of the sheet was found to be 3.7 MPa.
[0052] The obtained sheet was cut into pieces and then hot-pressed and vulcanized again at 145℃ for 20 minutes at a vulcanization pressure of 15MPa. The tensile strength of the reprocessed sheet was 2.5MPa.
[0053] Example 5
[0054] The method for preparing solid-phase recycled rubber in this embodiment includes the following steps:
[0055] Add 21g of sulfur to a three-necked flask, heat to 150℃, maintain for 5 min, then add 9g of lipoic acid and 0.9g of accelerator NMI, react for 6-8 h to obtain lipoic acid anti-vulcanization copolymer;
[0056] On an open mill, 2 parts of thioctic acid reverse vulcanization copolymer, 5 parts of zinc oxide, 1 part of stearic acid, 1.5 parts of accelerator CZ, 0.5 parts of accelerator DM, 1.5 parts of sulfur, and 20 parts of waste rubber powder (i.e., powdered waste rubber) (80 mesh) are added to 100 parts of isoprene rubber. After mixing evenly, vulcanization is carried out at a vulcanization temperature of 145℃, a vulcanization time of 30 min, and a vulcanization pressure of 15 MPa, finally obtaining solid phase reclaimed rubber (sheet).
[0057] The tensile strength of the sheet was tested according to the method described in Example 1, and the tensile strength of the sheet was found to be 25 MPa.
[0058] The sheet material was prepared into specimens 100 mm wide, 20 mm high, and 1 mm thick. A pre-crack was created in the middle of the specimen according to the GB / T 41941-2022 testing standard, and the fatigue threshold of the specimen was tested. The expected fatigue threshold of the sheet material was 500 J / m. 2 .
[0059] The fatigue threshold is the minimum energy required for crack propagation under cyclic loading. A curve showing the relationship between crack propagation rate and G is plotted using the formula G = W(λ)·H0 (where G is the energy release rate, W(λ) is the elastic energy stored in the specimen, and H0 is the initial length of the specimen). Figure 2 ), to obtain the fatigue threshold.
[0060] Example 6
[0061] The method for preparing solid-phase recycled rubber in this embodiment includes the following steps:
[0062] Add 45g of sulfur to a three-necked flask, heat to 160℃, maintain for 5 min, then add 45g of Span80 and 0.9g of accelerator ZDC, react for 3-4 h to obtain Span80 anti-vulcanization copolymer;
[0063] On an open mill, 2 parts of Span80 reverse vulcanization copolymer, 5 parts of zinc oxide, 1 part of stearic acid, 1.5 parts of accelerator CZ, 0.5 parts of accelerator DM, 1.5 parts of sulfur, and 20 parts of waste rubber powder (i.e., powdered waste rubber) (80 mesh) are added to 100 parts of isoprene rubber. After mixing evenly, vulcanization is carried out at a vulcanization temperature of 145℃, a vulcanization time of 30 min, and a vulcanization pressure of 15 MPa, finally obtaining solid phase reclaimed rubber (sheet).
[0064] The tensile strength of the sheet was tested according to the method described in Example 1, and the expected tensile strength of the sheet was 25 MPa. The fatigue threshold of the sheet was tested according to the method described in Example 5, and the expected fatigue threshold of the sheet was 500 J / m. 2 .
[0065] Comparative Example 1
[0066] Twenty-four portions of waste rubber powder (i.e., powdered waste rubber) (80 mesh) were hot-pressed and vulcanized at 145°C for 30 minutes at a vulcanization pressure of 15 MPa. Samples were cut according to the method described in Example 1, but complete dumbbell-shaped samples could not be obtained, and the samples lacked reprocessing capability. The results indicate that the interfacial interaction and properties of the solid-phase reclaimed rubber prepared based on the CH bond functionalization strategy were significantly improved.
[0067] Comparative Example 2
[0068] On an open mill, add 5 parts zinc oxide, 1 part stearic acid, 1.5 parts accelerator CZ, 0.5 parts accelerator DM, 1.5 parts sulfur, and 20 parts waste rubber powder (i.e., powdered waste rubber) (80 mesh) to 100 parts isoprene rubber. After mixing evenly, vulcanize at a vulcanization temperature of 145℃ for 30 minutes and a vulcanization pressure of 15MPa.
[0069] The tensile strength of the sheet was tested according to the method described in Example 1, and the tensile strength of the sheet was found to be 3.7 MPa. The fatigue threshold of the sheet was tested according to the method described in Example 5, and the fatigue threshold of the sheet was found to be approximately 50 J / m. 2 The test results show that the solid-phase reclaimed rubber (sheet) prepared based on the CH bond functionalization strategy obtained in this application has significantly increased tensile strength and fatigue threshold compared with traditional vulcanized rubber.
[0070] In summary, this application provides a method for preparing solid-phase recycled rubber based on a CH bond functionalization strategy. This application uses specific CH bond functionalized compounds as interface modifiers, which can significantly improve the interfacial interactions between solid-phase recycled rubbers and the tensile strength of solid-phase recycled rubbers under general rubber vulcanization conditions. This provides a new means for upgrading and recycling waste rubber and has good application scenarios.
[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
Claims
1. A solid-phase recycled rubber, characterized in that, The preparation materials include the following raw materials in parts by weight: 100 parts virgin rubber, 1-60 parts waste rubber, and 0.1-20 parts diazo compound; The virgin rubber is either natural rubber or synthetic rubber; The waste rubber is factory-grade waste rubber; The diazo compound is a diazo compound containing dynamic disulfide bonds or covalent bonds; The method for preparing the solid-phase recycled rubber includes the following steps: S1. Preparation of diazo compounds containing dynamic disulfide bonds: 2-hydroxyethyl disulfide, pyridine, and phenylacetyl chloride are dissolved in dichloromethane and reacted at room temperature. After purification, the first-step product is obtained. The first-step product, toluenesulfonyl azide, and 1,8-diazabicyclo[5.4.0]undec-7-ene are dissolved in dichloromethane and reacted at room temperature. After purification, the diazo compound containing dynamic disulfide bonds is obtained; or Preparation of diazo compounds containing covalent bonds: Ethylene glycol, pyridine, and phenylacetyl chloride were dissolved in dichloromethane and reacted at room temperature. After purification, the first product was obtained. The first product, toluenesulfonyl azide, and 1,8-diazabicyclo[5.4.0]undec-7-ene were dissolved in dichloromethane and reacted at room temperature. After purification, the diazo compound containing covalent bonds was obtained. S2. Preparation of solid-phase reclaimed rubber: The diazo compound containing dynamic disulfide bonds or covalent bonds, virgin rubber and waste rubber are mixed and hot-pressed at 100-145℃ for 15-30 min and at 10-15 MPa to obtain solid-phase reclaimed rubber.
2. The solid-phase recycled rubber according to claim 1, characterized in that, The virgin rubber is at least one of isoprene rubber, styrene-butadiene rubber, cis-butadiene rubber, nitrile rubber, butyl rubber, ethylene propylene rubber, and chloroprene rubber.
3. The solid-phase recycled rubber according to claim 1, characterized in that, In step S1, the molar ratio of 2-hydroxyethyl disulfide, pyridine and phenylacetyl chloride is 1:(0.5-6):(0.5-6), and the molar ratio of ethylene glycol, pyridine and phenylacetyl chloride is 1:(0.5-6):(0.5-6); the molar ratio of the first step product, toluenesulfonyl azide and 1,8-diazabicyclo[5.4.0]undec-7-ene is 1:(0.5-6):(0.5-6).
4. The use of the solid-phase recycled rubber according to any one of claims 1-3 in the preparation of gaskets, rubber blends or equipment for tire or bridge engineering materials.