Method for preparing high-performance sound-insulation outer wall material from waste plastics

Abstract

The invention belongs to the field of environment-friendly materials, and particularly relates to a method for preparing a high-performance sound-insulation outer wall material from waste plastics, the prepared sound-insulation outer wall material has excellent sound insulation performance, sound transmission can be effectively blocked in medium and low frequency bands and high frequency bands, the mechanical property of the material is remarkably enhanced, the safety and durability of the material are improved, and the service life of the material is prolonged. High economic benefits and market competitiveness are achieved, and large-scale application and popularization are facilitated.

Description

Technical Field

[0001] The invention relates to the field of environmentally friendly material preparation, and in particular to a method for preparing high-performance sound insulation exterior wall materials by utilizing waste plastics. Background Art

[0002] With the widespread application of plastic products in various fields, the amount of waste plastics has increased dramatically year by year, bringing tremendous pressure to the environment. Traditional treatment methods such as landfill and incineration not only occupy a large amount of land, but also seriously pollute the soil, water and air. In the field of building materials, sound insulation materials are crucial to improving the quality of indoor environment. However, there are many problems with existing sound insulation materials.

[0003] For example, although traditional sound insulation materials such as glass wool have certain sound insulation effects, their production costs are high, their production process consumes a lot of energy, and glass wool fibers may irritate the human respiratory tract, posing potential health hazards. In addition, the existing technology of using waste plastics to prepare building materials still needs to be improved in terms of sound insulation performance, mechanical properties and weather resistance, and cannot fully meet the high performance requirements of building exterior wall materials. For example, patent number CN2011101942308, "A kind of waste polypropylene plastic template for construction and its production process", although this patent involves the use of waste plastics to prepare building materials, may have deficiencies in sound insulation performance. Patent number CN102220064B, "Building waterproof coating converted from waste plastics and its production method", although it uses waste plastics, may not meet the requirements of high-performance sound insulation exterior wall materials in terms of mechanical properties and weather resistance. Patent number CN201110351345.8, "A kind of waste plastic building template and its manufacturing method", mainly focuses on the manufacture of building templates, and the improvement of sound insulation performance may not be significant enough. Therefore, it is necessary to develop a new method for preparing high-performance sound insulation exterior wall materials using waste plastics. Summary of the invention

[0004] The present invention provides a method for preparing a high-performance sound insulation exterior wall material using waste plastics, comprising the following steps:

[0005] Collect waste plastics, sort, screen, clean, dry and crush them to obtain waste plastic particles with a particle size of 1-3 mm;

[0006] Two modified compounds, 3-amino-4-propoxybenzoic acid methyl ester (APBM) and 2-(4-hydroxy-3-methoxyphenyl)-1,3-thiazolidine (HMTH), were prepared;

[0007] After mixing the waste plastic particles with APBM and HMTH in a mass ratio of 10:1:1 to 5:1:1, the mixture was stirred in a high-speed mixer at a speed of 1000-1500 rpm for 20-30 minutes to uniformly disperse the modified compounds;

[0008] The mixed material is added into a twin-screw extruder, mixed for 8-12 minutes at a temperature of 190-230°C and a screw speed of 180-250 rpm, and then extruded through a mold to form a plate with a thickness of 8-15 mm, and then cooled for 15-25 minutes by a combination of air cooling and water cooling to obtain a finished sound insulation exterior wall material.

[0009] Furthermore, the waste plastics are collected from waste plastic packaging, plastic containers and waste plastic household items, and a multi-stage cleaning process is adopted during the cleaning process, including rinsing with clean water, immersion and stirring cleaning with an aqueous solution containing a surfactant, and rinsing with clean water again. The drying temperature is 40-60°C and the drying time is 6-10 hours to ensure that the moisture content is less than 0.5%.

[0010] Furthermore, the synthesis method of the APBM comprises:

[0011] 1. Under nitrogen protection, add 0.5 mol of 3-amino-4-hydroxybenzoic acid, 1.5 mol of methanol and 5% of the total mass of the reactants into the reactor.

[0012] C, stirred and refluxed for 4-6 hours, cooled to room temperature after the reaction, neutralized with saturated sodium carbonate solution, extracted with ethyl acetate, dried over anhydrous sodium sulfate, filtered and distilled under reduced pressure to obtain 3

[0013] - amino-4-hydroxybenzoic acid methyl ester crude product;

[0014] 2. The crude product is transferred to another reaction vessel, 1.2 mol of propanol and 3% of the total mass of p-toluenesulfonic acid are added, heated to 80-100°C under nitrogen protection, stirred for reaction for 5-7 hours, and after the reaction is completed, neutralized, extracted, dried, and distilled to obtain APBM, with a yield of 70%-80% of the theoretical yield.

[0015] Furthermore, the synthesis method of HMTH comprises: adding 0.6 mole of 4-hydroxy-3-methoxybenzaldehyde and 0.6 mole of thioacetamide into a four-necked flask filled with ethanol solvent, dropping a few drops of glacial acetic acid as a catalyst, heating to 70-80° C. and reflux reaction for 6-8 hours, cooling to room temperature after the reaction, filtering to obtain a crude product, and purifying by recrystallization with ethanol to obtain HMTH, and the yield is 65%-75% of the theoretical yield.

[0016] Furthermore, the amino groups in the APBM molecules form hydrogen bonds with polar groups in the waste plastic molecules to enhance the binding force, the propoxy groups increase the molecular chain spacing and flexibility, reduce the melting temperature, and the ester groups improve flexibility and chemical corrosion resistance.

[0017] Furthermore, the hydroxyl groups in the HMTH molecules form hydrogen bonds with plastic molecules, the methoxy groups improve flexibility and processing performance through steric hindrance and electronic effects, the thiazolidine ring structure provides rigidity and stability, restricts the movement of the molecular chain, and its sulfur atoms interact with other substances to form a buffer layer to absorb and scatter sound waves.

[0018] Moreover, the structure has anti-oxidation properties and improves weather resistance.

[0019] On the other hand, the present invention also provides a sound insulation exterior wall material prepared according to the method, which has a sound insulation performance of 15-25 decibels higher in the medium, low and high frequency bands than materials prepared from traditional waste plastics, a tensile strength increased by 40%-60%, a bending strength increased by 50%-70%, good weather resistance, and a production cost reduced by 20%-30%.

[0020] Beneficial technical effects:

[0021] The propoxy group (-OC3H7) in Xinhecheng's modified compound has a certain flexibility. It can increase the distance between molecular chains, reduce the intermolecular force, and enable the material to deform better when impacted by sound waves, thereby consuming sound wave energy and improving sound insulation performance. The thiazolidine ring structure is a unique structural part of the compound, which provides the material with a certain rigidity and stability. When the material is subjected to external forces (such as sound wave impact or mechanical stress), the thiazolidine ring can limit the excessive movement of the molecular chain, allowing the material to maintain a good shape and structural integrity, thereby improving the mechanical properties of the material. At the same time, the sulfur atoms in the thiazolidine ring structure have a certain electron cloud density and can interact weakly with other substances (such as certain gas molecules in the air) to form a structure similar to a "buffer layer", which helps to absorb and scatter sound waves and further improve the sound insulation performance of the material. In addition, the structure also has certain antioxidant properties, can resist the aging effect of environmental factors such as ultraviolet rays and oxygen on the material, improve the weather resistance of the material, ensure the stability of the material during long-term outdoor use, and the prepared sound insulation exterior wall material has excellent sound insulation performance, which can effectively block the propagation of sound in the medium, low and high frequency bands. The sound insulation volume is 15-25 decibels higher than that of materials prepared from traditional waste plastics, which can significantly reduce the impact of external noise on the indoor environment and provide people with a quiet and comfortable living and working space. The mechanical properties of the material have been significantly enhanced, such as the tensile strength has been increased by 40%-60%, and the bending strength has been increased by 50%-70%, so that it can better withstand the various external forces (such as wind load, self-weight, etc.) to which the building exterior wall is subjected during use, and improve the safety and durability of the material. It has good weather resistance and can resist the erosion of harsh environmental factors such as ultraviolet radiation, temperature changes (such as high temperature and low temperature), humidity changes, and acid rain for a long time. It is not easy to have problems such as aging, discoloration, deformation and cracking, which prolongs the service life of the material and reduces the cost of building maintenance. Compared with traditional sound insulation materials, the production cost is reduced by 20%-30%, which has higher economic benefits and market competitiveness, and is conducive to large-scale promotion and application. DETAILED DESCRIPTION

[0022] Embodiment 1:

[0023] 1. Raw material preparation

[0024] 1. Collect waste plastics, including but not limited to discarded plastic packaging (such as plastic bags, plastic films, etc.), plastic containers (such as plastic bottles, plastic barrels, etc.) and discarded plastic household items (such as plastic chairs, plastic trash cans, etc.). The collected waste plastics need to be sorted and screened to remove non-plastic impurities (such as metal, paper, glass, etc.) and then cleaned. The cleaning process adopts a multi-stage cleaning process. First, use clean water to rinse off the dust and loose dirt on the surface, then soak and stir with an aqueous solution containing a surfactant to remove stubborn stains such as oil, and finally rinse with clean water. The washed waste plastics are dried at low temperature (40-60℃). The drying equipment can be a hot air circulation oven or a vacuum drying oven. The drying time depends on the type and water content of the plastic, generally 6-10 hours, to ensure that the water content of the plastic is less than 0.5%. The dried waste plastics are crushed using a crusher, and the particle size of the crushed plastic particles is controlled to be 1-3 mm for subsequent processing.

[0025] 2. Preparation and mechanism of action of modified compounds

[0026] 1. The first modified compound: 3-amino-4-propoxybenzoic acid methyl ester (APBM)

[0027] 1. Synthesis steps: Add a certain amount of 3-amino-4-hydroxybenzoic acid into a reactor equipped with a stirrer, thermometer, reflux condenser and nitrogen protection device.

[0028] (e.g. 0.5 mole), methanol (1.5 mole) and concentrated sulfuric acid (as a catalyst, the amount is about 5% of the total mass of the reactants). The reaction system is heated to 60-70°C and refluxed for 4-6 hours under stirring. After the reaction is completed, it is cooled to room temperature, the reaction mixture is poured into a separatory funnel, neutralized to neutrality with a saturated sodium carbonate solution, and then extracted with ethyl acetate (the number of extractions is 3-5 times). The organic phases are combined, dried over anhydrous sodium sulfate, filtered, and ethyl acetate is removed by vacuum distillation to obtain a crude product of 3-amino-4-hydroxybenzoic acid methyl ester. The crude product is transferred to another reaction vessel, and an appropriate amount of propanol (1.2 moles) and p-toluenesulfonic acid (as a catalyst, the amount is about 3% of the total mass of the reactants) are added, and heated to 80-100°C under nitrogen protection, and stirred for 5-7 hours. After the reaction is completed, pure 3-amino-4-propoxybenzoic acid methyl ester (APBM) is obtained according to the above-mentioned post-treatment method (neutralization, extraction, drying, distillation), and the yield is about 70%-80% of the theoretical yield.

[0029] 2. Structural characteristics and mechanism of action: The amino group (-NH2) in the molecule has strong polarity and can form hydrogen bonds with polar groups (such as carbonyl groups) in waste plastic molecules, thereby enhancing the binding force between the modified compound and the waste plastic, making the modifier better dispersed in the plastic matrix and improving the overall performance of the material. The propoxy group (-OC3H7) has a certain flexibility. It can increase the spacing between molecular chains, reduce the intermolecular force, and enable the material to deform better when impacted by sound waves, thereby consuming sound wave energy and improving sound insulation performance. At the same time, the presence of the propoxy group also helps to improve the processing performance of the material, reduce the melting temperature of the material, and make it easier to flow and form during processing. The ester group (-COO-) can improve the flexibility of the material on the one hand, and on the other hand, it can improve the chemical corrosion resistance of the material to a certain extent, protecting the material from erosion by external chemicals during long-term use, thereby extending the service life of the material, especially in the application scenario of building exterior walls exposed to various environmental factors, chemical corrosion resistance is particularly important.

[0030] 2. The second modified compound: 2-(4-hydroxy-3-methoxyphenyl)-1,3-thiazolidine (HMTH)

[0031] 1. Synthesis steps: In a four-necked flask equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser, first add an appropriate amount of ethanol (as a solvent), and then slowly add 4-hydroxy-3-methoxybenzaldehyde (0.6 mol) and thioacetamide (0.6 mol) under stirring. Then, add a few drops of glacial acetic acid as a catalyst, heat the reaction system to 70-80°C, and reflux for 6-8 hours. After the reaction is completed, the reaction mixture is cooled to room temperature and solids precipitate. The crude product is filtered and purified by recrystallization with ethanol to obtain pure 2-(4-hydroxy-3-methoxyphenyl)-1,3-thiazolidine (HMTH), with a yield of about 65%-75% of the theoretical yield.

[0032] 2. Structural characteristics and mechanism of action: The hydroxyl group (-OH) and the methoxy group (-OCH3) work together to enhance the compatibility between the compound and waste plastics. The hydroxyl group can form hydrogen bonds with plastic molecules to increase the interaction between molecules, while the methoxy group improves the flexibility and processing performance of the material through steric hindrance and electronic effects. The thiazolidine ring structure is a unique structural part of the compound, which provides a certain rigidity and stability to the material. When the material is subjected to external forces (such as sound wave impact or mechanical stress), the thiazolidine ring can limit the excessive movement of the molecular chain, so that the material maintains a good shape and structural integrity, thereby improving the mechanical properties of the material. At the same time, the sulfur atoms in the thiazolidine ring structure have a certain electron cloud density and can interact weakly with other substances (such as certain gas molecules in the air) to form a structure similar to a "buffer layer", which helps to absorb and scatter sound waves and further improve the sound insulation performance of the material. In addition, the structure also has certain antioxidant properties, which can resist the aging effects of environmental factors such as ultraviolet rays and oxygen on the material, improve the weather resistance of the material, and ensure that the material has stable performance during long-term outdoor use.

[0033] 3. Mixed modification

[0034] 1. Mix the waste plastic particles with two modified compounds (APBM and HMTH) in a mass ratio

[0035] The ratio of 10:1:1 to 5:1:1 is used. The mixing operation is carried out using a high-speed mixer with a stirring speed controlled at 1000-1500 rpm for 20-30 minutes to ensure that the modified compound is evenly dispersed in the waste plastic particles.

[0036] 4. Melt blending and molding

[0037] 1. Add the mixed materials into a twin-screw extruder for melt blending. The temperature of the extruder is set to 190-230°C, the screw speed is 180-250 rpm, and the blending time is 8-12 minutes. During the melt blending process, the modified compound is fully mixed with the waste plastic and chemically reacts to form a uniform composite material.

[0038] 2. Then, the melt-blended material is extruded through a die. The appropriate die can be selected according to the design requirements of the building's exterior wall, such as a flat die or a die with a specific pattern. The thickness of the extruded sheet is generally 8-15 mm. The extruded sheet is pulled by a traction device to maintain a stable shape and size, and then cooled to shape. The cooling method can be a combination of air cooling and water cooling. First, the surface temperature of the sheet is quickly reduced by air cooling, and then water cooling is performed to evenly reduce the internal temperature of the sheet. The cooling time is 15-25 minutes to ensure that the sheet is completely shaped and a finished sound insulation exterior wall material is obtained.

[0039] (I) Experimental setup

[0040] 1. Material Preparation

[0041] 1. Prepare the sound insulation exterior wall material samples by the following methods:

[0042] 1. Method 1: Traditional direct molding of waste plastics (no modified compounds are added, only the waste plastics are cleaned, crushed and molded).

[0043] 2. Method 2: A method of using the first modified compound (APBM) of the present invention alone for modification, and operating according to the above-mentioned preparation process of the present invention, but only adding the APBM modified compound.

[0044] 3. Method 3: A method of using the second modifying compound (HMTH) of the present invention for modification alone, also according to the preparation process of the present invention, only adding the HMTH modifying compound.

[0045] 4. Method 4: A method of using two modified compounds of the present invention to perform modification together (ie, the complete method of the present invention).

[0046] 2. For each preparation method, prepare multiple samples (at least 5) to ensure the reliability and statistical validity of the test results.

[0047] 2. Performance Testing

[0048] 1. Sound insulation performance test: Use acoustic testing equipment (such as impedance tube tester or reverberation chamber method) to test the material in different frequency ranges (100

[0049] -5000Hz) of sound insulation. The test environment temperature is controlled at 20±2℃ and the relative humidity is 40%-60%.

[0050] 2. Mechanical properties test

[0051] 1. Tensile strength test: Use a universal material testing machine to perform a tensile test on the material according to standard test methods (such as ASTM D638) to test the tensile strength and elongation at break of the sample. The test speed is set to 5mm / min, and the test environment conditions are the same as the sound insulation performance test.

[0052] 2. Bending strength test: According to the standard (such as ASTM D790), the three-point bending test method is used to test the bending strength and bending modulus of the material on a universal material testing machine. The span is determined according to the sample size, the loading speed is 2mm / min, and the environmental conditions remain unchanged.

[0053] 3. Weather resistance test

[0054] 1. Place the material sample in an artificial weathering chamber to simulate the light in the natural environment (using ultraviolet lamps to simulate the ultraviolet part of sunlight), temperature changes (setting cycle temperatures, such as -20°C to 60°C), humidity changes (relative humidity at 20%).

[0055] -90% cycle) and rain (regular water spraying to simulate rainfall). The aging time is set to different stages such as 500 hours, 1000 hours and 1500 hours.

[0056] 2. During and after the aging process, observe the appearance changes of the samples (such as color changes, whether cracks and powdering appear on the surface, etc.), and test the retention rate of its mechanical properties (tensile strength and flexural strength). The calculation method is the ratio of the mechanical property value after aging to the initial mechanical property value multiplied by 100%.

[0057] (II) Test results and analysis

[0058] 1. Sound insulation performance

[0059] 1. The average sound insulation of the traditional waste plastic direct molding material prepared by method 1 is 20-25 decibels in the frequency range of 100-5000 Hz.

[0060] 2. The average sound insulation of the material prepared by method 2 (only adding APBM modification) is increased to 28-33 decibels, which is about 30%-40% higher than that of traditional materials. This is mainly attributed to the fact that the propoxy and ester groups in APBM improve the flexibility and internal structure of the material, making it easier for sound waves to be consumed and scattered during propagation.

[0061] 3. The average sound insulation of the material prepared by method three (only adding HMTH modification) is 30-35 decibels, which is about 40%-60% higher than that of traditional materials. This is due to the combined effect of the hydroxyl, methoxy and thiazolidine ring structures in HMTH, which enhances the interaction between the material and sound waves and improves the sound insulation effect.

Claims

1. A method for preparing high-performance sound insulation exterior wall materials using waste plastics, characterized in that: The following steps are involved: S1 collects waste plastics, sorts, screens, cleans, dries and crushes them to obtain waste plastic particles with a particle size of 1-3 mm; S2 prepared two modified compounds, 3-amino-4-propoxybenzoic acid methyl ester (APBM) and 2-(4-hydroxy-3-methoxyphenyl)-1,3-thiazolidine (HMTH); S3: mixing the waste plastic particles with APBM and HMTH in a mass ratio of 10:1:1 to 5:1:1, and stirring the mixture in a high-speed mixer at a speed of 1000-1500 rpm for 20-30 minutes to uniformly disperse the modified compounds; S4 adds the mixed material into a twin-screw extruder, mixes it at a temperature of 190-230°C and a screw speed of 180-250 rpm for 8-12 minutes, and then extrude it through a mold to form a plate with a thickness of 8-15 mm, and then cools it for 15-25 minutes by combining air cooling and water cooling to obtain a finished sound insulation exterior wall material.

2. The method according to claim 1, characterized in that The waste plastics are collected from waste plastic packaging, plastic containers and waste plastic household items, and a multi-stage cleaning process is adopted during the cleaning process, including water rinsing, immersion and stirring cleaning with an aqueous solution containing a surfactant and water rinsing again. The drying temperature is 40-60°C and the drying time is 6-10 hours to ensure that the moisture content is less than 0.5%.

3. The method according to claim 1, characterized in that The synthesis method of the APBM comprises:

1. Under nitrogen protection, add 0.5 mol of 3-amino-4-hydroxybenzoic acid, 1.5 mol of methanol and 5% of concentrated sulfuric acid in the total mass of the reactants into a reactor, stir and reflux at 60-70°C for 4-6 hours, cool to room temperature after the reaction, neutralize with saturated sodium carbonate solution, extract with ethyl acetate, dry with anhydrous sodium sulfate, filter and distill under reduced pressure to obtain crude 3-amino-4-hydroxybenzoic acid methyl ester; 2. The crude product is transferred to another reaction vessel, 1.2 mol of propanol and 3% of the total mass of p-toluenesulfonic acid are added, heated to 80-100°C under nitrogen protection, stirred for reaction for 5-7 hours, and after the reaction is completed, neutralized, extracted, dried, and distilled to obtain APBM, with a yield of 70%-80% of the theoretical yield.

4. The method according to claim 1, characterized in that: The synthesis method of HMTH comprises: adding 0.6 mol of 4-hydroxy-3-methoxybenzaldehyde and 0.6 mol of thioacetamide into a four-necked flask filled with ethanol solvent, dropping a few drops of glacial acetic acid as a catalyst, heating to 70-80° C. for reflux reaction for 6-8 hours, cooling to room temperature after the reaction is completed, filtering to obtain a crude product, and purifying by recrystallization with ethanol to obtain HMTH, and the yield is 65%-75% of the theoretical yield.

5. The method according to claim 1, characterized in that The amino group in the APBM molecule forms hydrogen bonds with polar groups in the waste plastic molecules to enhance the bonding strength, the propoxy group increases the molecular chain spacing and flexibility, reduces the melting temperature, and the ester group improves flexibility and chemical corrosion resistance.

6. The method according to claim 1, characterized in that The hydroxyl groups in the HMTH molecules form hydrogen bonds with plastic molecules, the methoxy groups improve flexibility and processing performance through steric effects and electronic effects, the thiazolidine ring structure provides rigidity and stability and limits the movement of the molecular chain, and its sulfur atoms interact with other substances to form a buffer layer to absorb and scatter sound waves, and the structure has antioxidant properties to improve weather resistance.

7. A sound insulation exterior wall material prepared according to the method according to any one of claims 1 to 6, characterized in that: The sound insulation performance of this material is 15-25 decibels higher in the medium, low and high frequency bands than that of materials made from traditional waste plastics, the tensile strength is increased by 40%-60%, the bending strength is increased by 50%-70%, the weather resistance is good, and the production cost is reduced by 20%-30%.