High-strength reclaimed rubber and method for preparing the same
The microwave-radiated reclaimed rubber preparation process using a combination of modified carbon fiber and specific softener has solved the problems of low tensile strength and unstable Mooney viscosity in reclaimed rubber, achieving high-performance and environmentally friendly production of high-strength reclaimed rubber.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- QINGDAO UNIV OF SCI & TECH
- Filing Date
- 2025-09-28
- Publication Date
- 2026-06-26
AI Technical Summary
Existing reclaimed rubber has low tensile strength, unstable Mooney viscosity, and its traditional production process is complex, toxic, and harmful, requiring improvement.
High-strength reclaimed rubber was prepared by combining modified carbon fiber with a specific softener and through microwave radiation treatment and refining process. The modified carbon fiber was modified with silane coupling agent and double-terminated amino polysiloxane, and sulfonyl chloride polystyrene resin was added to improve mechanical properties and Mooney viscosity.
It significantly improves the mechanical properties, resistance to damp heat aging, and Mooney viscosity stability of reclaimed rubber, enhances processing performance and thermal conductivity, and reduces production costs and environmental pollution.
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Abstract
Description
Technical Field
[0001] This application relates to the field of rubber materials technology, and in particular to a high-strength reclaimed rubber and its preparation method. Background Technology
[0002] Rubber, as an important polymer material, has become a crucial raw material driving national economic development due to its unique viscoelasticity and low elastic modulus. my country is a major consumer of rubber products, resulting in a large amount of waste rubber materials generated annually. Coupled with China's relatively scarce rubber resources, a significant portion of rubber materials are imported. Therefore, the recycling and utilization of waste rubber is of great significance for replenishing my country's resources and addressing environmental pollution problems.
[0003] Reclaimed rubber is the main way to reuse waste rubber. Traditional reclaimed rubber production is carried out in recycling tanks, requiring waste rubber to undergo crushing, screening, heating, stirring, washing, dehydration, and refining. This process is complex, involving significant investment. Furthermore, the recycling process typically involves adding large amounts of softeners, coal tar, and petroleum extracts, resulting in unpleasant odors and toxicity. The tensile strength of the produced reclaimed rubber is also relatively low, generally between 8 and 10 MPa. Microwave radiation recycling, on the other hand, is environmentally friendly. It eliminates the need for large amounts of water, saving significant energy, and avoids the addition of toxic compounding agents. Moreover, the mechanical properties of the produced reclaimed rubber are not reduced compared to traditional methods, making it a currently popular reclaimed rubber production method.
[0004] Patent CN113024886A discloses a high-performance reclaimed rubber and its preparation method, including the following steps: (1) mixing waste rubber powder and calcium bicarbonate and treating with ultrasonic waves at a frequency of 200-300Hz for 1-3 minutes; (2) mixing the mixed rubber powder obtained in step (1) with stearic acid, palm oil, rosin, N-methyldiethanolamine, plant regenerator, and activator in a mixer at 80-100℃ for 5-10 minutes; (3) treating the mixed rubber powder obtained in step (2) with microwave radiation for 3-10 minutes, and refining the rubber obtained by microwave radiation treatment to obtain reclaimed rubber. However, the tensile strength of this reclaimed rubber is 10.9-12.1MPa and the elongation at break is 347-364%, and its mechanical properties need to be improved; in addition, Mooney viscosity is also an important indicator of reclaimed rubber, reflecting the quality of rubber processing performance and the molecular weight and distribution range, but this patent does not involve the Mooney viscosity of reclaimed rubber.
[0005] Therefore, it is necessary to provide a reclaimed rubber that combines Mooney viscosity stability with high strength. Summary of the Invention
[0006] The purpose of this application is to address the shortcomings of existing technologies by providing a high-strength reclaimed rubber and its preparation method.
[0007] To achieve the above objectives, the technical solution adopted in this application is as follows:
[0008] According to one aspect of this application, a high-strength reclaimed rubber is provided, comprising the following raw materials in parts by weight: 100 parts of waste rubber powder, 10-15 parts of softener, 0.5-2 parts of activator, 1-3 parts of nano zinc oxide, 3-5 parts of modified carbon fiber, and 0.5-2 parts of zinc stearate.
[0009] Among them, modified carbon fiber is obtained by modifying carbon fiber with silane coupling agent and double-terminated amino polysiloxane.
[0010] In the above-mentioned high-strength reclaimed rubber, as a preferred embodiment, the silane coupling agent includes a first silane coupling agent containing an epoxy group and a second silane coupling agent containing an amino group; the mass ratio of the first silane coupling agent and the second silane coupling agent is 10:(3-7); more preferably, the mass ratio of the first silane coupling agent and the second silane coupling agent is 10:5.
[0011] In the above-mentioned high-strength reclaimed adhesive, as a preferred embodiment, the total amount of the silane coupling agent is 20-30% of the carbon fiber mass; more preferably, the total amount of the silane coupling agent is 24% of the carbon fiber mass.
[0012] Optionally, the first silane coupling agent is selected from any one or a combination of several of 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-(2,3-epoxypropoxypropyl)methyldiethoxysilane, and 3-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.
[0013] Optionally, the second silane coupling agent is selected from 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-aminoethyl-3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-aminoethyl-3-aminopropyltriethoxysilane, N-2-aminoethyl-3-aminopropyltrimethoxysilane, N-(piperazinylethyl)-3-aminopropylmethyldimethoxysilane, 3-diethylenetriaminepropylmethyldimethoxysilane, 3-diethylenetriaminepropyltrimethoxysilane, N- Benzyl-N'-[3-(trimethoxysilyl)propyl]ethylenediamine hydrochloride, N-(2-dimethylaminoethyl)-3-aminopropylmethyldimethoxysilane, N-cyclohexyl-3-aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-(N-cyclohexylamino)propyltrimethoxysilane, N-(n-butyl)-3-aminopropyltriethoxysilane, N-(n-butyl)-3-aminopropyltrimethoxysilane, vinylbenzylaminoethylaminopropyltrimethoxysilane hydrochloride, bis(3-triethoxysilylpropyl)amine, bis(3-trimethoxysilylpropyl)amine, or a combination of several of these.
[0014] In the above-mentioned high-strength reclaimed adhesive, as a preferred embodiment, the amount of the double-terminated amino polysiloxane is 7-12% of the mass of the carbon fiber; more preferably, the amount of the double-terminated amino polysiloxane is 10% of the mass of the carbon fiber.
[0015] In the above-mentioned high-strength reclaimed adhesive, the modified carbon fiber is prepared by the following method:
[0016] (1) Disperse carbon fibers in a solvent, add silane coupling agent, and react at 50-70°C for 12-24 h to obtain silane coupling agent modified carbon fibers;
[0017] (2) Mix the silane coupling agent modified carbon fiber with double-terminated amino polysiloxane, add solvent, and purge with nitrogen for 4-8 hours to obtain modified carbon fiber.
[0018] Optionally, the solvent is toluene, xylene, or N,N-dimethylformamide; the amount of solvent used is not specifically limited, as long as it is sufficient to dissolve the modifier and achieve the modification reaction.
[0019] This application first modifies carbon fibers using two silane coupling agents, introducing silane coupling agents containing specific functional groups onto the carbon fiber surface. Then, it further modifies the carbon fibers using bi-amino-terminated polysiloxanes. The bi-amino-terminated polysiloxanes react with some of the epoxy groups in the silane coupling agents, thereby incorporating them into the carbon fiber surface and achieving surface modification. The modified carbon fibers exhibit improved dispersibility in the rubber matrix, increased interfacial bonding, and significantly enhanced mechanical properties of the reclaimed rubber. Compared to silane coupling agents with only one functional group, using two functional group silane coupling agents with controlled proportions allows for synergistic effects, reinforcing the reclaimed rubber while also improving its thermal conductivity and resistance to damp heat aging. Furthermore, compared to amino-containing silane coupling agents, an excess of epoxy-containing silane coupling agents allows for further reaction with bi-amino-terminated polysiloxanes, introducing bi-amino-terminated polysiloxanes, which further enhances the aging resistance of the reclaimed rubber and helps improve the stability of Mooney viscosity.
[0020] In the aforementioned high-strength reclaimed rubber, as a preferred embodiment, the softener is any one or a combination of several of palm oil, rice bran oil, naphthenic oil, soybean oil, turpentine oil, and kitchen waste oil; more preferably, the softener is palm oil and turpentine oil in a mass ratio of 1:(0.3-0.5). This application uses palm oil and turpentine oil as softeners in the reclaimed rubber, which improves the permeability and thermal expansion during the desulfurization process, enhances the desulfurization effect, and thus increases the strength of the reclaimed rubber.
[0021] In the above-mentioned high-strength reclaimed rubber, as a preferred embodiment, the activator is selected from tetramethylthiuram disulfide and / or dimethyldiphenylthiuram disulfide.
[0022] In a preferred embodiment of the above-mentioned high-strength reclaimed rubber, 5-10 parts of sulfonyl chloride polystyrene resin are further added, wherein the sulfonyl chloride content of the sulfonyl chloride polystyrene resin is 2.0-2.6 mmol / g. The addition of sulfonyl chloride polystyrene resin to the reclaimed rubber allows the sulfonyl chloride groups in the resin to interact with the rubber molecules, which helps improve the reclaimed rubber's resistance to damp heat aging, and also helps to increase Mooney viscosity and improve processing performance.
[0023] According to another aspect of this application, a method for preparing high-strength reclaimed rubber is provided, comprising the following steps:
[0024] S1. Mix the raw materials according to the proportion and put them into the desulfurization tank. Heat the mixture to desulfurize and obtain a desulfurized mixture.
[0025] S2, the desulfurization mixture is cooled to below 45°C, refined in a refining machine, and then sheeted to obtain high-strength reclaimed rubber.
[0026] In the above-mentioned high-strength reclaimed rubber, as a preferred embodiment, in step S1, the heating and pressurization process is as follows: first, the temperature is raised to 150-180°C and held at this temperature for 15-30 minutes; then, the temperature is raised to 200-220°C and held at this temperature for 5-10 minutes.
[0027] In the above-mentioned high-strength reclaimed rubber, as a preferred embodiment, in step S2, the refining temperature is 50-70°C.
[0028] Compared with the prior art, this application has the following beneficial effects:
[0029] 1. This application provides a high-strength reclaimed rubber in which the components work synergistically to give the resulting reclaimed rubber not only excellent mechanical properties and stable Mooney viscosity, good processing performance, but also excellent resistance to damp heat aging and thermal conductivity.
[0030] 2. The high-strength reclaimed rubber of this application, with the addition of modified carbon fiber, greatly improves the mechanical properties, resistance to damp heat aging, Mooney viscosity stability, and thermal conductivity of the reclaimed rubber. Using palm oil and turpentine as softeners in the reclaimed rubber can enhance the penetration of softeners into the cross-linking network of the rubber during the desulfurization process, weaken the intermolecular forces of the rubber, strengthen the desulfurization effect, and thus improve the strength of the reclaimed rubber. Detailed Implementation
[0031] The following non-limiting embodiments are intended to enable those skilled in the art to gain a more comprehensive understanding of this application, but do not limit this application in any way. The following content is merely an exemplary description of the scope of protection claimed in this application, and those skilled in the art can make various changes and modifications to the invention based on the disclosed content, which should also fall within the scope of protection claimed in this application.
[0032] The present application will be further described below by way of specific embodiments. Unless otherwise specified, all chemical reagents used in the embodiments of this application are obtained through conventional commercial means.
[0033] Example 1
[0034] A high-strength rubber comprises the following raw materials in parts by weight: 100 parts waste rubber powder, 10 parts softener, 0.5 parts activator, 1 part nano zinc oxide, 5 parts modified carbon fiber, and 0.5 parts zinc stearate.
[0035] In this embodiment, the activator is tetramethylthiuram disulfide; the softener is palm oil.
[0036] Modified carbon fibers were prepared by the following method: carbon fibers were dispersed in sufficient xylene, and 20% of the carbon fiber mass of silane coupling agent was added. The mixture was reacted at 50°C for 12 hours to obtain silane coupling agent modified carbon fibers. The silane coupling agent modified carbon fibers were mixed with bi-amino-terminated polysiloxane (the amount of bi-amino-terminated polysiloxane was 7% of the carbon fiber mass), sufficient solvent was added, and nitrogen gas was introduced for 4 hours to obtain modified carbon fibers. The silane coupling agent included 3-glycidoxypropyltrimethoxysilane and 3-aminopropylmethyldimethoxysilane in a mass ratio of 10:3.
[0037] The above-mentioned high-strength rubber was prepared by the following method:
[0038] S1. Mix the raw materials according to the proportion and put them into the desulfurization tank. Heat the mixture to 150°C and keep it at that temperature for 30 minutes. Then heat the mixture to 200°C and keep it at that temperature for 10 minutes to complete the desulfurization and obtain the desulfurization mixture.
[0039] S2, the desulfurization mixture is cooled to below 45°C, refined in a refining machine at 50°C, and then sheeted to obtain high-strength reclaimed rubber.
[0040] Example 2
[0041] A high-strength rubber comprises the following raw materials in parts by weight: 100 parts waste rubber powder, 15 parts softener, 2 parts activator, 3 parts nano zinc oxide, 3 parts modified carbon fiber, and 2 parts zinc stearate.
[0042] In this embodiment, the activator is tetramethylthiuram disulfide; the softener is palm oil.
[0043] Modified carbon fibers were prepared by the following method: carbon fibers were dispersed in sufficient xylene, and 24% (by weight of the carbon fibers) of silane coupling agent was added. The mixture was reacted at 70°C for 24 hours to obtain silane coupling agent modified carbon fibers. The silane coupling agent modified carbon fibers were mixed with bi-amino-terminated polysiloxane (the amount of bi-amino-terminated polysiloxane was 10% of the carbon fiber mass), and sufficient solvent was added. The mixture was then purged with nitrogen and reacted for 8 hours to obtain modified carbon fibers. The silane coupling agent consisted of 3-glycidoxypropyltrimethoxysilane and 3-aminopropylmethyldimethoxysilane in a mass ratio of 10:5.
[0044] The above-mentioned high-strength rubber was prepared by the following method:
[0045] S1. Mix the raw materials according to the proportion and put them into the desulfurization tank. Heat the mixture to 170°C and keep it at that temperature for 15 minutes. Then heat the mixture to 220°C and keep it at that temperature for 5 minutes to complete the desulfurization and obtain the desulfurization mixture.
[0046] S2, the desulfurization mixture is cooled to below 45°C, refined in a refining machine at 70°C, and then sheeted to obtain high-strength reclaimed rubber.
[0047] Example 3
[0048] The difference from Example 2 is that the modified carbon fiber was prepared by the following method: carbon fiber was dispersed in sufficient xylene, 30% of the carbon fiber mass of silane coupling agent was added, and the mixture was reacted at 70°C for 24 hours to obtain silane coupling agent modified carbon fiber; the silane coupling agent modified carbon fiber was mixed with double-terminated amino polysiloxane (the amount of double-terminated amino polysiloxane was 12% of the carbon fiber mass), sufficient solvent was added, and nitrogen gas was introduced to react for 8 hours to obtain modified carbon fiber; the silane coupling agent included 3-glycidoxypropyltrimethoxysilane and 3-aminopropylmethyldimethoxysilane in a mass ratio of 10:7.
[0049] Example 4
[0050] The difference from Example 2 is that, in the preparation of modified carbon fiber, the silane coupling agent includes 3-glycidoxypropyltrimethoxysilane and 3-aminopropylmethyldimethoxysilane in a mass ratio of 1:1, and the total amount remains unchanged.
[0051] Example 5
[0052] The difference from Example 2 is that, in the preparation of modified carbon fiber, the silane coupling agent includes 3-glycidoxypropyltrimethoxysilane and 3-aminopropylmethyldimethoxysilane in a mass ratio of 5:1, and the total amount remains unchanged.
[0053] Example 6
[0054] The difference from Example 2 is that, in the preparation of modified carbon fiber, the amount of silane coupling agent used is 40% of the mass of carbon fiber.
[0055] Example 7
[0056] The difference from Example 2 is that, in the preparation of modified carbon fiber, the amount of double-terminated amino polysiloxane is 15% of the mass of carbon fiber.
[0057] Example 8
[0058] The difference from Example 2 is that the softener is palm oil and turpentine oil in a mass ratio of 1:0.3.
[0059] Example 9
[0060] The difference from Example 2 is that the softener is palm oil and turpentine oil in a mass ratio of 1:0.5.
[0061] Example 10
[0062] The difference from Example 2 is that 5 parts of sulfonyl chloride polystyrene resin were added to the high-strength rubber, and the sulfonyl chloride content of the sulfonyl chloride polystyrene resin was 2.0 mmol / g.
[0063] Example 11
[0064] The difference from Example 2 is that 10 parts of sulfonyl chloride polystyrene resin were added to the high-strength rubber, and the sulfonyl chloride content of the sulfonyl chloride polystyrene resin was 2.6 mmol / g.
[0065] Example 12
[0066] The difference from Example 10 is that the sulfonyl chloride polystyrene resin has a sulfonyl chloride content of 3.2 mmol / g.
[0067] Example 13
[0068] The difference from Example 10 is that the amount of sulfonyl chloride polystyrene resin added is 13 parts.
[0069] Comparative Example 1
[0070] The difference from Example 2 is that the modified carbon nanotubes are replaced with an equal amount of unmodified carbon nanotubes.
[0071] Comparative Example 2
[0072] The difference from Example 2 is that the modified carbon nanotubes are replaced with silane coupling agent modified carbon nanotubes, and the preparation method of silane coupling agent modified carbon nanotubes is the same as that in Example 2.
[0073] Experimental Example 1
[0074] The reclaimed rubber obtained in the above examples and comparative examples was tested according to GB / T13460-2016; the thermal conductivity of the reclaimed rubber was tested according to GB / T11205-2009; after aging the reclaimed rubber in an oven at 100°C and RH=95% for 7 days, its tensile strength was tested, and the tensile strength retention rate was calculated.
[0075] The results are shown in Tables 1 and 2 below. It can be seen that the reclaimed rubber prepared in this application has a tensile strength of up to 19 MPa and up to 20 MPa, a small Mooney viscosity variation and high stability, excellent processing performance, and excellent thermal conductivity and resistance to wet aging.
[0076] Table 1. Mechanical properties and Mooney viscosity of reclaimed rubber
[0077]
[0078] Table 2. Thermal conductivity and resistance to damp heat aging of reclaimed rubber
[0079]
[0080] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, this application is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of this application without departing from the scope of this application should be within the protection scope of this application.
Claims
1. A high-strength reclaimed rubber, characterized in that, The raw materials include the following parts by weight: 100 parts waste rubber powder, 10-15 parts softener, 0.5-2 parts activator, 1-3 parts nano zinc oxide, 3-5 parts modified carbon fiber, and 0.5-2 parts zinc stearate; Among them, modified carbon fiber is obtained by modifying carbon fiber with silane coupling agent and double-terminated amino polysiloxane; The silane coupling agent comprises a first silane coupling agent containing epoxy groups and a second silane coupling agent containing amino groups; the mass ratio of the first silane coupling agent to the second silane coupling agent is 10:(3-7); the total amount of the silane coupling agent is 20-30% of the mass of the carbon fiber. The amount of the double-terminated amino polysiloxane is 7-12% of the mass of the carbon fiber.
2. The high-strength reclaimed rubber according to claim 1, characterized in that, The modified carbon fiber was prepared by the following method: (1) Disperse carbon fibers in a solvent, add silane coupling agent, and react at 50-70°C for 12-24 h to obtain silane coupling agent modified carbon fibers; (2) Mix the silane coupling agent modified carbon fiber with double-terminated amino polysiloxane, add xylene solvent, and purge with nitrogen for 4-8 hours to obtain modified carbon fiber.
3. The high-strength reclaimed rubber according to claim 1, characterized in that, The softener is palm oil and turpentine oil in a mass ratio of 1:(0.3-0.5).
4. The high-strength reclaimed rubber according to any one of claims 1-3, characterized in that, The high-strength reclaimed rubber also contains 5 to 10 parts of sulfonyl chloride polystyrene resin, wherein the sulfonyl chloride polystyrene resin is a sulfonyl chloride polystyrene resin with a sulfonyl chloride content of 2.0 to 2.6 mmol / g.
5. The high-strength reclaimed rubber according to claim 1, characterized in that, The activator is selected from tetramethylthiuram disulfide and / or dimethyldiphenylthiuram disulfide.
6. The method for preparing the high-strength reclaimed rubber according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Mix all raw materials according to the proportion and put them into the desulfurization tank. Heat the tank to desulfurize and obtain a desulfurization mixture. S2, the desulfurization mixture is cooled to below 45°C, refined in a refining machine, and then sheeted to obtain high-strength reclaimed rubber.
7. The preparation method according to claim 6, characterized in that, The heating and pressurization process is as follows: first, heat to 150-180℃ and hold at that temperature for 15-30 minutes; then heat to 200-220℃ and hold at that temperature for 5-10 minutes.
8. The preparation method according to claim 6, characterized in that, The refining temperature is 50-70℃.