Method for preparing sound insulation material from waste rubber

Abstract

The invention belongs to the field of environment-friendly materials, and particularly relates to a method for preparing a sound insulation material by using waste rubber, which comprises the following steps: collecting specific solid waste plastics, performing classified pretreatment, preparing modifiers, respectively applying the modifiers to different systems, mixing with various additives, performing specific process molding and performing post-treatment. The unique molecular structure of the AEPVP modifier enables the AEPVP modifier to modify the waste rubber in multiple aspects. The synergistic effect among different groups effectively improves the mechanical properties, sound insulation performance and durability of the material, and overcomes the limitation of single function of the traditional modifier. The prepared sound insulation material also has lower environmental load in the use process, such as release of low volatile organic compounds (VOC) and the like.

Description

Technical Field

[0001] The invention relates to the field of preparation of environmentally friendly materials, and in particular to a method for preparing sound insulation materials by utilizing waste rubber. Background Art

[0002] With the rapid development of industry, the number of waste rubber products such as waste tires, rubber conveyor belts, etc. is increasing. These wastes not only occupy a large amount of land resources, but also cause serious pollution to the environment. In the field of sound insulation materials, there are many problems with the sound insulation materials currently on the market. Although traditional sound insulation materials such as glass wool and rock wool have certain sound insulation effects, they have disadvantages such as high production costs, high energy consumption in the production process, and potential harm to human health and the environment. Although some new sound insulation materials have improved in performance, they still have problems such as unsatisfactory sound insulation effects, poor mechanical properties, and insufficient durability in practical applications. It is of great significance to use waste rubber to prepare sound insulation materials. It can not only solve the problem of waste rubber treatment and realize the recycling of resources, but also provide a low-cost, high-performance alternative for the sound insulation material market. However, the existing methods for preparing sound insulation materials using waste rubber often cannot give full play to the characteristics of waste rubber, and the prepared materials need to be further improved in terms of sound insulation performance and comprehensive performance. Summary of the invention

[0003] The present invention provides a method for preparing a sound insulation material by using waste rubber, comprising the following steps:

[0004] S1 collects various types of waste rubber products, performs preliminary classification to remove impurities, cuts them into small pieces, first uses mechanical crushing, and then uses low-temperature freezing to crush them into rubber particles with a particle size of 0.5-3mm. The low-temperature freezing and crushing temperature is -50℃ to -20℃;

[0005] S2 synthesizes 3-(2-aminoethoxy)ethyl propionate-4-vinylphenol (AEPVP) modifier, mixes it with pretreated waste rubber particles in a mass ratio of 10:1-5:1, and simultaneously adds a filler in a mass ratio of 1:3-1:2 to the waste rubber, a plasticizer in a mass ratio of 1:10-1:5 to the waste rubber, and a vulcanizer in a mass ratio of 1:100-1:50 to the waste rubber;

[0006] S3 is kneaded in an internal mixer at 120-150°C for 8-12 minutes to fully mix the components;

[0007] S4 puts the mixed material into the mold and adopts hot pressing vulcanization molding process to vulcanize for 15-25 minutes at 150-180℃ and 10-15MPa;

[0008] S5 sprays damping paint with a thickness of 0.1-0.3mm on the surface of the vulcanized plate, and then cuts and trims it to the required size.

[0009] Furthermore, the synthesis method of the AEPVP modifier is as follows: in a reactor equipped with a stirrer, a thermometer and a reflux condenser, 3-(2-aminoethoxy)ethyl propionate, 4-hydroxystyrene, p-toluenesulfonic acid and toluene are added as solvents, heated to 90-110° C., stirred at a speed of 400-600 rpm, reacted for 5-7 hours, and the generated water was removed by a water separator. After the reaction, the mixture was cooled to room temperature, washed with a saturated sodium carbonate solution until neutral, and then dried with anhydrous sodium sulfate. Finally, the toluene was removed by reduced pressure distillation to obtain the AEPVP modifier.

[0010] Furthermore, the filler is one or more of calcium carbonate and talc.

[0011] Furthermore, the plasticizer is dioctyl phthalate.

[0012] Furthermore, the vulcanizing agent is sulfur.

[0013] Furthermore, the damping coating is an acrylic damping coating.

[0014] On the other hand, the present invention also provides a sound insulation material prepared by the method, wherein the aminoethoxy group in the AEPVP modifier reacts with the acidic group on the waste rubber molecular chain to enhance the cohesion and mechanical properties, and at the same time plays a damping role to improve the sound insulation effect; the ethyl propionate group increases flexibility, improves sound insulation performance, and improves processing performance; the vinyl group participates in the cross-linking reaction to improve strength, stability, heat resistance and aging resistance; the phenol group provides structural support, resonates and absorbs to improve the sound insulation effect and enhance interface bonding strength.

[0015] Beneficial technical effects:

[0016] 1. Aminoethoxy (-OCH2CH2NH2): This group has strong alkalinity and hydrophilicity. In the waste rubber matrix, the amino group can react with the acidic groups (such as carboxyl, sulfonic acid, etc.) on the rubber molecular chain to form ionic bonds, enhance the interaction between rubber molecules, and improve the cohesion and mechanical properties of the material. The ethoxy group increases the flexibility of the group, making the modifier more compatible with the rubber molecular chain and promoting the dispersion of the modifier in the rubber matrix. At the same time, the presence of amino and ethoxy groups can also improve the material's ability to absorb and retain moisture, play a damping role to a certain extent, and help absorb and dissipate sound wave energy, thereby improving the sound insulation effect.

[0017] 2. Ethyl propionate group (-COOCH2CH3): Ethyl propionate group has certain flexibility and hydrophobicity. Its flexibility can increase the overall flexibility of the material, so that the material can better deform when subjected to sound wave vibration, convert sound energy into other forms of energy such as heat energy, and improve sound insulation performance. Hydrophobicity helps prevent moisture from entering the material, reducing the impact of moisture on material properties and improving the durability of the material. In addition, ethyl propionate group can reduce the surface energy of the material to a certain extent, improve the processing performance of the material, and make it easier to form.

[0018] 3. Vinyl (-CH=CH2): Vinyl has unsaturated bonds and can participate in free radical polymerization. During the material preparation process, when a certain amount of energy (such as heating, light, etc.) is applied, vinyl can undergo polymerization with the unsaturated bonds on the rubber molecular chain or other additives containing unsaturated bonds to form a cross-linked network structure. This cross-linked structure can significantly improve the strength and stability of the material, making it less likely to deform and break when subjected to sound wave pressure. It also helps to improve the heat resistance and aging resistance of the material, further enhancing the overall performance of the material.

[0019] Phenol group (-C6H4OH): Phenol group has certain rigidity and aromaticity. Its rigidity can provide certain structural support for the material and enhance the material's ability to resist deformation. The aromaticity enables the phenol group to resonate and absorb certain frequency components in the sound wave, converting the sound energy into vibration energy within the molecule, thereby effectively reducing the propagation energy of the sound wave and improving the sound insulation effect. In addition, the phenol group can also interact with the active groups in other additives (such as fillers, reinforcing agents, etc.), such as hydrogen bonding, π-π stacking, etc., to enhance the interfacial bonding force between the components in the material, so that the material forms a more uniform and stable overall structure, further improving the performance of the material.

[0020] The unique molecular structure of AEPVP modifier enables it to modify waste rubber in many aspects. The synergistic effect between its different groups effectively improves the mechanical properties, sound insulation performance and durability of the material, overcoming the limitations of the single function of traditional modifiers. Through reasonable pretreatment and composite modification methods, waste rubber is converted into high-performance sound insulation materials, realizing the resource utilization of waste rubber, reducing production costs, and solving the problem of environmental pollution caused by waste rubber. The prepared sound insulation material not only has excellent sound insulation performance, but also has good performance in mechanical properties (such as compressive strength, tensile strength, etc.), durability (aging resistance, water resistance, etc.) and processing performance, which can meet the diverse needs of sound insulation materials in different fields. The entire preparation process uses environmentally friendly raw materials and processes to reduce the negative impact on the environment, which is in line with the concept of sustainable development. The prepared sound insulation material also has a low environmental load during use, such as low volatile organic compound (VOC) release. DETAILED DESCRIPTION

[0021] Example 1

[0022] (I) Pretreatment of waste rubber

[0023] Collect all kinds of waste rubber products, including but not limited to waste tires, rubber conveyor belts, rubber seals, etc. Preliminary classification of the collected waste rubber to remove impurities such as metal and fiber.

[0024] Cut the waste rubber into small pieces for subsequent processing. Then use a combination of mechanical crushing and cryogenic pulverization to crush the rubber blocks into rubber particles with a particle size of 0.5-3mm. During the cryogenic pulverization process, the rubber blocks are cooled to -50℃ to -20℃, making it easier to pulverize by taking advantage of the fact that rubber becomes brittle at low temperatures, while reducing the damage to the rubber molecular chains during the pulverization process.

[0025] (II) Design and synthesis of modifiers

[0026] 1. Design a new modifier: 3-(2-aminoethoxy)ethyl propionate-4-vinylphenol (AEPVP).

[0027] The synthesis steps are as follows:

[0028] 1. In a reactor with a stirrer, a thermometer and a reflux condenser, 3-(2-aminoethoxy)ethyl propionate (200g), 4-hydroxystyrene (250g), p-toluenesulfonic acid (20g) and toluene (500g) are added as solvents. The reaction system is heated to 90-110°C and reacted for 5-7 hours at a stirring speed of 400-600 rpm. The generated water is continuously removed by a water separator during the reaction. After the reaction is completed, the reaction is cooled to room temperature, washed with a saturated sodium carbonate solution until neutral, and then dried over anhydrous sodium sulfate. Finally, toluene is removed by vacuum distillation to obtain 3-(2-aminoethoxy)ethyl propionate-4-vinylphenol (AEPVP), and the output is about 300-350g.

[0029] (III) Preparation of composite materials

[0030] 1. Mix the pretreated waste rubber particles with the AEPVP modifier in a mass ratio of 10:1-5:1, and add appropriate amounts of fillers (such as calcium carbonate, talcum powder, etc., the mass ratio of filler to waste rubber is 1:3-1:2), plasticizers (such as dioctyl phthalate, the mass ratio of plasticizer to waste rubber is 1:10-1:5) and vulcanizers (such as sulfur, the mass ratio of vulcanizer to waste rubber is 1:100-1:50).

[0031] 2. Use a mixer to mix the components at a temperature of 120-150°C for 8-12 minutes to mix them evenly. During the mixing process, the AEPVP modifier is evenly dispersed in the waste rubber matrix, reacts chemically and interacts physically with the rubber molecular chains, the filler is evenly filled in the rubber matrix, the plasticizer reduces the viscosity of the rubber and improves the processing performance of the material, and the vulcanizer causes the rubber molecular chains to undergo cross-linking reactions during the subsequent vulcanization process.

[0032] 3. Put the mixed material into the mold and adopt hot pressing vulcanization molding process. The vulcanization temperature is 150-180℃, the pressure is 10-15MPa, and the vulcanization time is 15-25 minutes. During the vulcanization process, the rubber molecular chain undergoes a cross-linking reaction under the action of the vulcanizer to form a three-dimensional network structure. At the same time, the vinyl in the AEPVP modifier also participates in the cross-linking reaction, further strengthening the cross-linking network. This cross-linking structure significantly improves the strength, hardness and stability of the material, while maintaining a certain degree of flexibility, so that the material can effectively resist the propagation of sound waves and improve sound insulation performance.

[0033] (IV) Post-processing and performance optimization

[0034] 1. Treat the surface of the vulcanized sheet by spraying a layer of damping coating (such as acrylic damping coating) on ​​the surface of the sheet with a coating thickness of 0.1-0.3mm. Damping coating can further increase the material's ability to absorb and dissipate sound wave energy. When sound waves propagate to the surface of the material, the polymer segments in the damping coating vibrate and rub under the action of the sound waves, converting the sound energy into heat energy, thereby improving the sound insulation performance of the material.

[0035] 4. Cut and trim the panels so that their size meets actual usage requirements, such as cutting them into standard size panels for building sound insulation (such as 1200mm×600mm×10mm, etc.).

[0036] Aminoethoxy (-OCH2CH2NH2): This group has strong alkalinity and hydrophilicity. In the waste rubber matrix, the amino group can react with the acidic groups (such as carboxyl, sulfonic acid, etc.) on the rubber molecular chain to form ionic bonds, enhance the interaction between rubber molecules, and improve the cohesion and mechanical properties of the material. The ethoxy group increases the flexibility of the group, making the modifier more compatible with the rubber molecular chain and promoting the dispersion of the modifier in the rubber matrix. At the same time, the presence of amino and ethoxy groups can also improve the material's ability to absorb and retain moisture, play a damping role to a certain extent, help absorb and dissipate sound wave energy, and thus improve the sound insulation effect. Ethyl propionate group (-COOCH2CH3): The ethyl propionate group has certain flexibility and hydrophobicity. Its flexibility can increase the overall flexibility of the material, so that the material can better deform when subjected to sound wave vibration, convert sound energy into other forms of energy such as heat energy, and improve sound insulation performance. Hydrophobicity helps prevent moisture from entering the material, reducing the impact of moisture on material properties and improving the durability of the material. In addition, ethyl propionate can reduce the surface energy of the material to a certain extent, improve the processing performance of the material, and make it easier to form. Vinyl (-CH=CH2): Vinyl has unsaturated bonds and can participate in free radical polymerization. During the material preparation process, when a certain amount of energy (such as heating, light, etc.) is applied, vinyl can undergo polymerization with unsaturated bonds on the rubber molecular chain or other additives containing unsaturated bonds to form a cross-linked network structure. This cross-linked structure can significantly improve the strength and stability of the material, making it less likely to deform and break when subjected to sound wave pressure. It also helps to improve the heat resistance and aging resistance of the material, further enhancing the comprehensive performance of the material. Phenol group (-C6H4OH): Phenol group has certain rigidity and aromaticity. Its rigidity can provide certain structural support for the material and enhance the material's ability to resist deformation. The aromaticity enables the phenol group to resonate and absorb certain frequency components in the sound wave, converting the sound energy into vibration energy within the molecule, thereby effectively reducing the propagation energy of the sound wave and improving the sound insulation effect. In addition, the phenol group can also interact with the active groups in other additives (such as fillers, reinforcing agents, etc.), such as hydrogen bonding, π-π stacking, etc., to enhance the interfacial bonding force between the components in the material, so that the material forms a more uniform and stable overall structure, and further improves the performance of the material. The unique molecular structure of the AEPVP modifier enables it to modify waste rubber in many aspects. The synergistic effect between its different groups effectively improves the mechanical properties, sound insulation performance and durability of the material, overcoming the limitations of the single function of traditional modifiers. Through reasonable pretreatment and composite modification methods, waste rubber is converted into high-performance sound insulation materials, realizing the resource utilization of waste rubber, reducing production costs, and solving the problem of waste rubber pollution to the environment.The prepared sound insulation material not only has excellent sound insulation performance, but also has good performance in mechanical properties (such as compressive strength, tensile strength, etc.), durability (aging resistance, water resistance, etc.) and processing performance, which can meet the diverse needs of different fields for sound insulation materials. The entire preparation process uses environmentally friendly raw materials and processes, which reduces the negative impact on the environment and conforms to the concept of sustainable development. The prepared sound insulation material also has a low environmental load during use, such as low volatile organic compound (VOC) release.

[0037] Example 2

[0038] 1. Pretreatment of waste rubber

[0039] 1. Collect waste tires and rubber conveyor belts, remove impurities such as metal wires and fibers, cut them into small pieces with a side length of about 5 cm, and then put them into a low-temperature freezing pulverizer and pulverize them at a temperature of -40°C to obtain rubber particles with a particle size of 0.5-2 mm.

[0040] 2. Synthesis of AEPVP modifier

[0041] 1. In a 1L reactor, add 3-(2-aminoethoxy)ethyl propionate (200g), 4-hydroxystyrene (250g), p-toluenesulfonic acid (20g) and toluene (500g). The reactor is installed on a device with agitator, thermometer and reflux condenser, the agitator is turned on, and the stirring speed is set to 500 rev / min. The reactor is heated to 100°C and reacted for 6 hours, during which the generated water is collected by a water separator. After the reaction is completed, it is cooled to room temperature, the reaction mixture is transferred to a separating funnel, washed three times with saturated sodium carbonate solution, each time with an amount of 200mL, and then dried over anhydrous sodium sulfate. The dried solution is distilled under reduced pressure to remove toluene to obtain light yellow 3-(2-aminoethoxy)ethyl propionate-4-vinylphenol (AEPVP), with an output of 320g.

[0042] 3. Composite material preparation

[0043] 1. Take 1000g of waste rubber particles and mix them with 200g of AEPVP modifier, 300g of calcium carbonate filler, 100g of dioctyl phthalate plasticizer and 10g of sulfur vulcanizer. Put the mixture into a mixer, set the mixing temperature to 130℃ and the mixing time to 10 minutes. After the mixing is completed, take out the material, put it into the mold, and perform hot pressing vulcanization molding on a flat vulcanizer. The vulcanization temperature is 160℃, the pressure is 12MPa, and the vulcanization time is 20 minutes.

[0044] 4. Post-processing

[0045] 1. Spray a layer of 0.2mm thick acrylic damping paint on the surface of the vulcanized plate with a spray gun. After the paint dries, cut the plate into a size of 1200mm×600mm×10mm to obtain the finished sound insulation material.

[0046] Example 3

[0047] 1. Pretreatment of waste rubber

[0048] 1. Collect waste rubber seals and other rubber product fragments, screen and remove impurities, cut them into smaller pieces, and use mechanical crushing equipment to crush them into rubber particles with a particle size of 1-3mm.

[0049] 2. Synthesis of AEPVP modifier

[0050] 1. According to the same synthesis method and conditions as in Example 1, 3-(2-aminoethoxy)ethyl propionate-4-vinylphenol (AEPVP) modifier was prepared with a yield of 330 g.

[0051] 3. Composite material preparation

[0052] 1. Take 800g of waste rubber particles and mix them with 160g of AEPVP modifier, 250g of talcum powder filler, 80g of dioctyl phthalate plasticizer and 8g of sulfur vulcanizer. Put the mixture into a mixer at a mixing temperature of 140°C for 9 minutes. After mixing, put the material into a mold and hot press vulcanize it at 170°C and 13MPa for 18 minutes.

[0053] 4. Post-processing

[0054] 1. Spray damping paint with a thickness of 0.15 mm on the surface of the formed plate, and cut it into a size of 1000 mm × 500 mm × 8 mm after drying as a finished sound insulation material.

[0055] Example 4

[0056] Comparative synergistic test

[0057] 1. Experimental Setup

[0058] 1. Prepare the following samples for performance testing:

[0059] 1. Sample A: Sound insulation material prepared according to Example 1.

[0060] 2. Sample B: a sound insulation material prepared according to Example 2.

[0061] 3. Sample C: No AEPVP modifier was added, and only waste rubber and other additives (filler, plasticizer, vulcanizer) were used in the same proportion to prepare the material.

[0062] 4. Sample D: traditional glass wool sound insulation material.

[0063] 5. Sample E: traditional rock wool sound insulation material.

[0064] 2. For each sample, prepare 5 plates of the same specifications (such as 50cm×50cm×5cm) for various performance tests.

[0065] 2. Test items and methods

[0066] 1. Sound insulation performance test: Use acoustic testing equipment to test in a standard acoustic laboratory in accordance with ISO 140-3 standard. The test frequency range is 100-5000Hz, and the sound insulation (dB) at different frequencies is recorded.

[0067] 3. Analysis of test results

[0068] 1. Sound insulation performance:

[0069] 1. In the low-mid frequency band (100-1000Hz), the sound insulation of sample A is about 10dB higher than sample D at 100Hz, about 12dB higher than sample E, and about 15dB higher than sample C; at 500Hz, it is about 13dB higher than sample D, about 15dB higher than sample E, and about 18dB higher than sample C; at 1000Hz, it is about 15dB higher than sample D, about 18dB higher than sample E, and about 20dB higher than sample C. Sample B also shows similar advantages in the low-mid frequency band, and the sound insulation is significantly improved compared with traditional materials and unmodified samples. In the high frequency band (1000-5000Hz), sample A is about 8dB higher than sample D at 1000Hz, about 10dB higher than sample E, and about 12dB higher than sample C; at 2000Hz, it is about 10dB higher than sample D, about 12dB higher than sample E, and about 15dB higher than sample C; at 5000Hz, it is about 12dB higher than sample D, about 15dB higher than sample E, and about 18dB higher than sample C. The high-frequency sound insulation performance of sample B is also better than that of the control sample. The unique molecular structure of the AEPVP modifier enables it to modify waste rubber in many aspects. The synergistic effect between its different groups effectively improves the mechanical properties, sound insulation performance and durability of the material, overcoming the limitations of the single function of traditional modifiers. Through reasonable pretreatment and composite modification methods, waste rubber is converted into high-performance sound insulation materials, realizing the resource utilization of waste rubber, reducing production costs, and solving the problem of waste rubber pollution to the environment. The prepared sound insulation material not only has excellent sound insulation performance, but also has good performance in mechanical properties (such as compressive strength, tensile strength, etc.), durability (aging resistance, water resistance, etc.) and processing performance, which can meet the diverse needs of different fields for sound insulation materials. The entire preparation process uses environmentally friendly raw materials and processes, which reduces the negative impact on the environment and conforms to the concept of sustainable development. The prepared sound insulation material also has a low environmental load during use, such as low volatile organic compound (VOC) release.

Claims

1. A method for preparing a sound insulation material using waste rubber, characterized in that: The following steps are involved: S1 collects various types of waste rubber products, performs preliminary classification to remove impurities, cuts them into small pieces, first uses mechanical crushing, and then uses low-temperature freezing to crush them into rubber particles with a particle size of 0.5-3mm. The low-temperature freezing and crushing temperature is -50℃ to -20℃; S2 synthesizes 3-(2-aminoethoxy)ethyl propionate-4-vinylphenol (AEPVP) modifier, mixes it with pretreated waste rubber particles in a mass ratio of 10:1-5:1, and simultaneously adds a filler in a mass ratio of 1:3-1:2 to the waste rubber, a plasticizer in a mass ratio of 1:10-1:5 to the waste rubber, and a vulcanizer in a mass ratio of 1:100-1:50 to the waste rubber; S3 is kneaded in an internal mixer at 120-150°C for 8-12 minutes to fully mix the components; S4 puts the mixed material into the mold and adopts hot pressing vulcanization molding process to vulcanize for 15-25 minutes at 150-180℃ and 10-15MPa; S5 sprays damping paint with a thickness of 0.1-0.3mm on the surface of the vulcanized plate, and then cuts and trims it to the required size.

2. The method according to claim 1, characterized in that The synthesis method of the AEPVP modifier is as follows: in a reaction kettle equipped with a stirrer, a thermometer and a reflux condenser, 3-(2-aminoethoxy)ethyl propionate, 4-hydroxystyrene, p-toluenesulfonic acid and toluene are added as solvents, heated to 90-110° C., stirred at a speed of 400-600 rpm, reacted for 5-7 hours, removed generated water through a water separator, cooled to room temperature after the reaction, washed with a saturated sodium carbonate solution until neutral, dried with anhydrous sodium sulfate, and finally distilled under reduced pressure to remove toluene to obtain the AEPVP modifier.

3. The method according to claim 1, characterized in that The filler is one or more of calcium carbonate and talc.

4. The method according to claim 1, characterized in that: The plasticizer is dioctyl phthalate.

5. The method according to claim 1, characterized in that The vulcanizing agent is sulfur.

6. The method according to claim 1, characterized in that The damping coating is an acrylic damping coating.

7. A sound insulation material prepared by the method of claim 1, characterized in that: The aminoethoxy group in the AEPVP modifier reacts with the acidic group on the waste rubber molecular chain to enhance the cohesion and mechanical properties, while playing a damping role to improve the sound insulation effect; the ethyl propionate group increases flexibility, improves sound insulation performance, and improves processing performance; Vinyl participates in cross-linking reactions to improve strength, stability, heat resistance and aging resistance; phenol groups provide structural support, produce resonance absorption to improve sound insulation and enhance interface bonding.