Anti-aging MPP single-wall corrugated pipe and preparation method thereof

Abstract

The invention relates to an anti-aging MPP (modified polypropylene) single-wall corrugated pipe and a preparation method thereof, and belongs to the technical field of high polymer materials, and the anti-aging MPP single-wall corrugated pipe is prepared from the following raw materials: polypropylene resin, modified nano titanium dioxide, a toughening agent, a defoaming agent, talcum powder and a microencapsulation antioxidant. Wherein the modified nano titanium dioxide is prepared by coating the surface of the nano titanium dioxide with an amorphous silicon dioxide layer and synchronously doping zinc oxide quantum dots, and after the modified nano titanium dioxide is added, the resistance effect of the corrugated pipe on ultraviolet radiation can be remarkably enhanced, aging is delayed, and the physical property stability is improved. The microencapsulated antioxidant is formed by wrapping an antioxidant 1010 with a polyurea formaldehyde shell layer, and the shell layer contains amino groups, so that the antioxidant can be slowly released to inhibit oxidation and aging, the compatibility and stability of the material can be enhanced, the comprehensive performance of the corrugated pipe is finally effectively improved, and the service life of the corrugated pipe is prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and relates to an anti-aging MPP single-wall corrugated pipe and a preparation method thereof. Background Art

[0002] Polypropylene single-wall corrugated pipe is a new type of pipe made mainly of polypropylene (PP). It has the characteristics of light weight, low cost, smooth inner wall and small water flow resistance, and is widely used in municipal drainage, building ventilation, farmland irrigation and other fields. At the same time, its good chemical stability and insulation also enable it to operate stably under some special working conditions.

[0003] With the increase of service time, the polypropylene single-wall corrugated pipe gradually ages, and ultraviolet radiation is one of the key factors leading to aging. Ultraviolet light has high energy. When it irradiates the surface of the polypropylene single-wall corrugated pipe for a long time, a series of complex photochemical reactions will be triggered. Prolonged irradiation of ultraviolet light, the photon energy is sufficient to break the chemical bonds in the polypropylene molecular chain, causing the molecular chain to break, crosslink and other reactions. The breakage of the molecular chain leads to a decrease in the molecular weight of the polymer, and then the mechanical properties of the pipe decrease, such as poorer flexibility and increased hardness; while the crosslinking reaction will make the material brittle and reduce its impact resistance. These changes make the pipe physically prone to rupture and cracking, and its sealing and integrity are affected; chemically, its corrosion resistance also weakens, and it is difficult to resist the erosion of the conveying medium and external chemical substances, greatly shortening the service life of the pipe.

[0004] Therefore, how to effectively solve the aging problem of polypropylene single-wall corrugated pipe caused by ultraviolet radiation and improve its service life and performance stability has become a key problem that needs to be solved urgently at present. Summary of the Invention

[0005] The purpose of the present invention is to provide an anti-aging MPP single-wall corrugated pipe and a preparation method thereof, which can effectively improve the resistance of the corrugated pipe to ultraviolet light and significantly delay the aging process.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] In the first aspect, the present invention proposes an anti-aging MPP single-wall corrugated pipe, adopting the following technical solution:

[0008] An anti-aging MPP single-wall corrugated pipe, the single-wall corrugated pipe is made of raw materials comprising the following parts by weight:

[0009]

[0010] Further, the preparation method of the modified nano-titanium dioxide specifically includes the following steps:

[0011] S1. Mix titanium dioxide nanoparticles, tetraethyl orthosilicate and zinc nitrate in a weight ratio of 100:(15 - 30):(2 - 8), and then add them to an anhydrous ethanol solution for ultrasonic dispersion to form a uniform suspension;

[0012] S2. Adjust the pH of the suspension to 9 - 11, and coat an amorphous silica layer on the surface of the titanium dioxide nanoparticles through the sol - gel method, and simultaneously dope zinc oxide quantum dots into the silica layer;

[0013] S3. Calcinate at 600 - 800 °C for 2 - 4 hours to obtain modified titanium dioxide nanoparticles.

[0014] Preferably, the titanium dioxide nanoparticles are anatase type, the weight portion of the titanium dioxide nanoparticles is 100 parts, the weight portion of the tetraethyl orthosilicate is 15 - 30 parts, and the weight portion of the zinc nitrate is 2 - 8 parts.

[0015] Furthermore, it further comprises a microencapsulated antioxidant, and the weight portion of the microencapsulated antioxidant is 0.3 - 1.2 parts.

[0016] Furthermore, the microencapsulated antioxidant is composed of antioxidant 1010 wrapped by a polyurea - formaldehyde shell.

[0017] Furthermore, the surface of the polyurea - formaldehyde shell of the microencapsulated antioxidant contains amino groups.

[0018] Preferably, the preparation method of the microencapsulated antioxidant specifically comprises the following steps:

[0019] Y1. Disperse antioxidant 1010 in water, add urea and 37% formaldehyde solution, and stir to form a prepolymer, wherein the weight ratio of antioxidant 1010, urea and 37% formaldehyde solution is 10:(8.4 - 12):(12.6 - 18);

[0020] Y2. Adjust the pH of the prepolymer to 3 - 5, raise the temperature to 60 - 80 °C, and react for 3 - 5 hours for in - situ polymerization;

[0021] Y3. Filter, wash and then dry to obtain the microencapsulated antioxidant.

[0022] In the second aspect, the present invention provides a preparation method of an anti - aging MPP single - wall corrugated pipe, adopting the following technical scheme:

[0023] A preparation method of an anti - aging MPP single - wall corrugated pipe, comprising the following steps:

[0024] Z1. Premix the modified titanium dioxide nanoparticles, talcum powder and polypropylene resin in a high - speed mixer, control the temperature at 40 - 60 °C and the rotation speed at 1200 - 1500 rpm;

[0025] Z2. Add a toughening agent, a defoaming agent and a microencapsulated antioxidant, and continue to mix until homogeneous;

[0026] Z3. Melt-blend and pelletize through a twin-screw extruder, and set the barrel temperature to 180 - 220 °C;

[0027] Z4. Extrude and shape through a single-wall corrugated pipe forming machine, with the die head temperature of 190 - 210 °C and the cooling water temperature of 10 - 25 °C.

[0028] Advantages of the present invention:

[0029] (1) By constructing a "TiO 2 @SiO 2 / ZnO" heterojunction structure, the present invention endows the anti-aging MPP single-wall corrugated pipe with unique ultraviolet resistance. In terms of physical shielding, nano-titanium dioxide has good absorption capacity for UV-A / B (280 - 400 nm), and due to the quantum size effect, zinc oxide quantum dots can effectively absorb UV-C (<280 nm). The two work together to broaden the absorption range of ultraviolet rays, achieving coverage of the UV-A / B / C band, and greatly reducing the direct irradiation of ultraviolet rays on the pipe. In terms of chemical passivation, the presence of the silica insulating layer blocks the migration of photo-generated electron-hole pairs, and combined with the energy band matching design of the type-II heterojunction, the photocatalytic activity is biased towards the UV-C band, and UV-C will be filtered by the atmosphere in the natural environment, thus reducing the damage caused by the photocatalytic reaction to the pipe, realizing effective protection of the single-wall corrugated pipe, and significantly delaying its aging process.

[0030] (2) The present invention also introduces a microencapsulated antioxidant, providing a synergistic protection mechanism of dynamic self-repair and free radical neutralization for the single-wall corrugated pipe. When microcracks appear on the surface of the pipe, the microcapsules will rupture and release the antioxidant. The antioxidant can quickly neutralize free radicals and at the same time repair the broken PP molecular chains, thus effectively preventing the further expansion of cracks and maintaining the physical properties of the pipe. In addition, the amino groups on the surface of the polyurea formaldehyde shell have the function of active adsorption and protection. It can preferentially adsorb ·OH free radicals generated by photocatalysis, forming a double defense line of "physical barrier + chemical repair", which can not only timely remove harmful free radicals, but also inhibit the occurrence of photocatalytic reactions to a certain extent, further enhancing the anti-aging performance of the pipe and ensuring that the single-wall corrugated pipe maintains good performance and stability during long-term use. Specific embodiments

[0031] To further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following combines examples to detail the specific embodiments, structures, features and their effects of the present invention as follows.

[0032] The polypropylene resins in all examples and comparative examples of the present invention were purchased from Shanghai Jiakesai Plastic Co., Ltd., Exxon POE-6202 was purchased from Langfang Haozheng Plastic Technology Co., Ltd., BYK-055 was purchased from Jining Tangyi Chemical Co., Ltd., antioxidant 1010 was purchased from Lianyungang Supply Chain Management Co., Ltd., urea was purchased from Jinan Xinhaoyang Biotechnology Co., Ltd., tetraethyl orthosilicate was purchased from Zhangjiagang Jinshilun Chemical Technology Co., Ltd., and anatase-type nano-titanium dioxide was purchased from Ningbo Jiweina New Materials Technology Co., Ltd.

[0033] Example 1

[0034] An anti-aging MPP single-wall corrugated pipe, the single-wall corrugated pipe is made of raw materials comprising the following parts by weight:

[0035]

[0036]

[0037] Among them, the toughening agent is selected from Exxon POE-6202, and the defoaming agent is selected from BYK-055.

[0038] The preparation method of the modified nano-titanium dioxide specifically includes the following steps:

[0039] S1. Mix anatase-type nano-titanium dioxide, tetraethyl orthosilicate and zinc nitrate according to a weight ratio of 100:15:2, then add them to 500 mL of anhydrous ethanol solution, and ultrasonically disperse them at a power of 500 W and a frequency of 40 kHz at room temperature for 30 minutes to form a uniform suspension. Among them, the nano-titanium dioxide is anatase-type, and the weight is 100 g;

[0040] S2. Drop 25% ammonia water into the suspension to adjust the pH of the suspension to 9.0, heat it up to 50 °C, and stir and react at 200 rpm for 6 hours. A non-crystalline silica layer is coated on the surface of the nano-titanium dioxide by the sol-gel method, and at the same time Zn 2+ hydrolyzes to generate zinc oxide quantum dots, which are doped in the silica layer;

[0041] S3. Centrifuge and separate the product, wash it 3 times with deionized water, dry it at 80 °C for 12 hours, and then heat it up to 600 °C at a rate of 5 °C / min in a muffle furnace and calcine it for 4 hours to obtain TiO 2 @SiO 2 / ZnO composite powder (i.e., modified nano-titanium dioxide).

[0042] The microencapsulated antioxidant is composed of a polyurea formaldehyde shell layer wrapping antioxidant 1010.

[0043] Furthermore, the polyurea formaldehyde shell layer of the microencapsulated antioxidant contains amino groups on its surface.

[0044] The preparation method of the microencapsulated antioxidant specifically comprises the following steps:

[0045] Y1. Disperse 10 g of antioxidant 1010 in 200 mL of deionized water, add 8.4 g of urea and 12.6 g of 37% formaldehyde solution, and stir at 300 rpm for 30 minutes to form a prepolymer;

[0046] Y2. Adjust the pH of the prepolymer to 3.0 with 10% citric acid, raise the temperature to 80 °C, and react for 3 hours. Polyurea formaldehyde in-situ polymerizes on the surface of the antioxidant to form a shell layer, and the surface of the shell layer has residual amino groups of unreacted urea;

[0047] Y3. Cool the reaction solution to 25 °C, filter, wash with ethanol 3 times, and then dry in vacuum at 50 °C for 12 hours to obtain the microencapsulated antioxidant.

[0048] A preparation method of an anti-aging MPP single-wall corrugated pipe comprises the following steps:

[0049] Z1. Premix modified nano-titanium dioxide, talcum powder and polypropylene resin in a high-speed mixer, control the temperature at 40 °C, the rotation speed at 1500 rpm, and premix for 15 minutes;

[0050] Z2. Add a toughening agent, a defoaming agent and the microencapsulated antioxidant, and continue to mix until uniform;

[0051] Z3. Use a twin-screw extruder, and set the barrel temperature in zones: zone 1 at 180 °C, zone 2 at 200 °C, zone 3 at 210 °C, zone 4 at 220 °C, the screw rotation speed at 300 rpm, and melt extrude and pelletize;

[0052] Z4. Put the pellets into a single-wall corrugated pipe forming machine, the die head temperature is 190 °C, the cooling water tank temperature is 10 °C, the traction speed is 2 m / min, and after shaping, a single-wall corrugated pipe with a pipe diameter of 110 mm and a wall thickness of 2.5 mm is obtained.

[0053] Example 2

[0054] An anti-aging MPP single-wall corrugated pipe, and the single-wall corrugated pipe is made of raw materials comprising the following parts by weight:

[0055]

[0056] Among them, the toughening agent is selected as Exxon POE-6202, and the defoaming agent is selected as BYK-055.

[0057] The preparation method of the modified nano-titanium dioxide specifically comprises the following steps:

[0058] S1. Mix anatase titanium dioxide, tetraethyl orthosilicate, and zinc nitrate in a weight ratio of 100:22.5:5, then add them to 500 mL of anhydrous ethanol solution, and ultrasonically disperse at a power of 500 W and a frequency of 40 kHz for 30 minutes at room temperature to form a uniform suspension. Among them, the titanium dioxide is anatase type, and the weight portion is 100 g;

[0059] S2. Drop 25% ammonia water into the suspension to adjust the pH to 10.0, raise the temperature to 60 °C, and stir and react at 200 rpm for 4 hours. Coat an amorphous silica layer on the surface of the titanium dioxide through the sol-gel method, and at the same time, Zn 2+ Generate zinc oxide quantum dots and dope them into the silica layer;

[0060] S3. Centrifuge and separate the product, wash it 3 times with deionized water, dry it at 80 °C for 12 hours, and then heat it to 700 °C at a rate of 5 °C / min in a muffle furnace and calcine it for 3 hours to obtain TiO 2 @SiO 2 / ZnO composite powder (i.e., modified titanium dioxide).

[0061] The microencapsulated antioxidant is composed of an antioxidant 1010 wrapped by a polyurea formaldehyde shell layer.

[0062] Furthermore, the surface of the polyurea formaldehyde shell layer of the microencapsulated antioxidant contains amino groups.

[0063] The preparation method of the microencapsulated antioxidant specifically includes the following steps:

[0064] Y1. Disperse 10 g of antioxidant 1010 in 200 mL of deionized water, add 10 g of urea and 15 g of 37% formaldehyde solution, and stir at 300 rpm for 30 minutes to form a prepolymer;

[0065] Y2. Adjust the pH of the prepolymer to 4.0 with 10% citric acid, raise the temperature to 70 °C, and react for 4 hours. Polyurea formaldehyde in-situ polymerizes on the surface of the antioxidant to form a shell layer, and the surface of the shell layer has residual amino groups through unreacted urea;

[0066] Y3. Cool the reaction solution to 25 °C, filter it, wash it 3 times with ethanol, and dry it in vacuum at 50 °C for 12 hours to obtain the microencapsulated antioxidant.

[0067] A preparation method of an anti-aging MPP single-wall corrugated pipe includes the following steps:

[0068] Z1. Premix the modified titanium dioxide, talcum powder, and polypropylene resin in a high-speed mixer, control the temperature at 50 °C, the rotation speed at 1400 rpm, and premix for 15 minutes;

[0069] Z2. Add a toughening agent, an antifoaming agent and a microencapsulated antioxidant, and continue to mix until homogeneous;

[0070] Z3. Use a twin-screw extruder, and set the barrel temperature in zones: zone 1 at 190 °C, zone 2 at 205 °C, zone 3 at 215 °C, zone 4 at 220 °C, and the screw speed at 300 rpm, and melt and extrude into pellets;

[0071] Z4. Put the pellets into a single-wall corrugated pipe forming machine, with the die head temperature at 205 °C, the cooling water tank temperature at 20 °C, and the traction speed at 2 m / min. After shaping, a single-wall corrugated pipe with a pipe diameter of 110 mm and a wall thickness of 2.5 mm is obtained.

[0072] Example 3

[0073] An anti-aging MPP single-wall corrugated pipe, and the single-wall corrugated pipe is made of raw materials comprising the following parts by weight:

[0074]

[0075] Among them, the toughening agent is selected as Exxon POE-6202, and the antifoaming agent is selected as BYK-055.

[0076] The preparation method of the modified nano-titanium dioxide specifically includes the following steps:

[0077] S1. Mix anatase-type nano-titanium dioxide, tetraethyl orthosilicate and zinc nitrate in a weight ratio of 100:30:8, and then add them to a 500 mL anhydrous ethanol solution, and ultrasonically disperse at room temperature with a power of 500 W and a frequency of 40 kHz for 30 minutes to form a uniform suspension. Among them, the nano-titanium dioxide is anatase-type, and the weight part is 100 g;

[0078] S2. Drop 25% ammonia water into the suspension to adjust the pH to 11.0, heat up to 70 °C, and stir and react at 200 rpm for 2 hours. Coat an amorphous silica layer on the surface of the nano-titanium dioxide by the sol-gel method, and at the same time Zn 2+ generate zinc oxide quantum dots and dope them into the silica layer;

[0079] S3. Centrifuge and separate the product, wash it 3 times with deionized water, and dry it at 80 °C for 12 hours. Then, heat it up to 800 °C at a rate of 5 °C / min in a muffle furnace and calcine it for 2 hours to obtain TiO 2 @SiO 2 / ZnO composite powder (i.e., modified nano-titanium dioxide).

[0080] The microencapsulated antioxidant is composed of an antioxidant 1010 wrapped by a polyurea formaldehyde shell layer.

[0081] Furthermore, the polyurea formaldehyde shell layer of the microencapsulated antioxidant contains amino groups on its surface.

[0082] The preparation method of the microencapsulated antioxidant specifically includes the following steps:

[0083] Y1. Disperse 10 g of antioxidant 1010 in 200 mL of deionized water, add 12 g of urea and 18 g of 37% formaldehyde solution, and stir at 300 rpm for 30 minutes to form a prepolymer;

[0084] Y2. Adjust the pH of the prepolymer to 5.0 with 10% citric acid, raise the temperature to 60 °C, and react for 5 hours. Polyurea formaldehyde in-situ polymerizes on the surface of the antioxidant to form a shell layer, and the surface of the shell layer has residual amino groups of unreacted urea;

[0085] Y3. Cool the reaction solution to 25 °C, filter, wash with ethanol 3 times, and dry in vacuum at 50 °C for 12 hours to obtain the microencapsulated antioxidant.

[0086] A preparation method of an anti-aging MPP single-wall corrugated pipe includes the following steps:

[0087] Z1. Premix modified nano-titanium dioxide, talcum powder and polypropylene resin in a high-speed mixer, control the temperature at 60 °C, the rotation speed at 1200 rpm, and premix for 15 minutes;

[0088] Z2. Add a toughening agent, a defoaming agent and the microencapsulated antioxidant, and continue to mix until uniform;

[0089] Z3. Use a twin-screw extruder, and set the barrel temperature in zones: zone 1 at 200 °C, zone 2 at 210 °C, zone 3 at 215 °C, zone 4 at 220 °C, the screw rotation speed at 300 rpm, and melt extrude and pelletize;

[0090] Z4. Put the pellets into a single-wall corrugated pipe forming machine, the die head temperature is 210 °C, the cooling water tank temperature is 25 °C, the traction speed is 2 m / min, and after shaping, a single-wall corrugated pipe with a pipe diameter of 110 mm and a wall thickness of 2.5 mm is obtained.

[0091] Comparative Example 1

[0092] The difference from Example 2 is that: anatase-type nano-titanium dioxide of equal amount is used to replace the modified nano-titanium dioxide.

[0093] Comparative Example 2

[0094] The difference from Example 2 is that: antioxidant 1010 of equal amount is used to replace the microencapsulated antioxidant.

[0095] Comparative Example 3

[0096] The difference from Example 2 is that: anatase-type nano-titanium dioxide of equal amount is used to replace the modified nano-titanium dioxide, and antioxidant 1010 of equal amount is used to replace the microencapsulated antioxidant.

[0097] Test Example 1

[0098] Sample test: Conducted in accordance with GB / T 16422.3-2014. The MPP single-wall corrugated pipe samples prepared in Example 2 and each comparative example were cut into standard specimens with dimensions of 150 mm in length, 15 mm in width, and 2.5 mm in thickness, and a UV-B 313 nm lamp tube was used with the irradiation intensity set at 0.76 W / m 2 , and the standard specimens were tested under the conditions of 60 °C / 8 h light + 50 °C / 4 h condensation cycle for a duration of 2000 h.

[0099] Among them, the irradiation intensity of the UV-B 313 nm lamp tube was calibrated using a standard irradiance meter calibrated by the national metrology department. Before the test, the standard irradiance meter was placed at the position where the sample was located to ensure that the irradiation intensity was set at 0.76 W / m 2 . During the calibration process, if it is found that the deviation between the actual irradiation intensity and the set value exceeds ±5%, the lamp tube will be adjusted or replaced.

[0100] Data calculation:

[0101] Before the start of the aging test, the tensile strength and elongation at break of each test specimen were tested using a universal material testing machine. After the 2000 h aging test was completed and the sample was cooled to room temperature, the tensile strength and elongation at break of the aged specimen were tested again using a universal material testing machine.

[0102] Tensile strength retention rate: Tensile strength retention rate = (tensile strength of the aged sample / tensile strength of the sample before aging) × 100%.

[0103] Elongation at break retention rate: Elongation at break retention rate = (elongation at break of the aged sample / elongation at break of the sample before aging) × 100%.

[0104] Surface crack density: By observing the surface of the sample, the number of cracks per unit area (per square centimeter) was counted.

[0105] The higher the values of the tensile strength retention rate and the elongation at break retention rate, the better the mechanical properties of the sample are retained after the anti-aging test, and the stronger the anti-aging performance of the material. The lower the value of the surface crack density, the fewer cracks are generated on the surface of the sample during the aging process, and the better the anti-aging performance of the material.

[0106] The specific data of Test Example 1 are shown in Table 1

[0107] Table 1:

[0108]

[0109] Test Example 2

[0110] The MPP single-wall corrugated pipes prepared in Example 2 and each comparative example were cut into samples with dimensions of 10 mm × 10 mm × 2.5 mm, and 3 parallel samples were prepared for each group of samples. The samples were immersed in a phosphate buffer solution (pH 7.4) containing 5 mM DMPO (5,5-dimethyl-1-pyrroline-N-oxide) for 30 minutes to ensure that ·OH free radicals were captured to form stable DMPO-OH adducts, and then the samples were placed in a specific ultraviolet irradiation environment and irradiated for 48 h. Among them, a UVGL-58 type ultraviolet lamp was selected as the specific ultraviolet light source, and its emission wavelength was mainly concentrated at 254 nm, and the light intensity was 5 mW / cm 2 . An electron spin resonance spectrometer (ESR) was used to detect the samples after ultraviolet irradiation to obtain the ·OH free radical concentration data, and finally the free radical scavenging rate was calculated. Among them, the test parameters were as follows: the microwave power was set to 10 mW, the magnetic field range was 3400 - 3600 G, the modulation frequency was 100 kHz, the modulation amplitude was 1 G, the scanning time was 60 S, and the time constant was 0.1 S.

[0111] Blank group setting: Prepare blank control samples (such as nano-titanium dioxide, antioxidants, etc.) made of the same material as the test samples but without adding any anti-aging components, and process and test them according to the same method.

[0112] Free radical scavenging rate = [(·OH free radical concentration in the blank control group - ·OH free radical concentration in the sample group) / ·OH free radical concentration in the blank control group] × 100%.

[0113] The higher the free radical scavenging rate value, the stronger the ability of the material to scavenge ·OH free radicals, and the better the antioxidant performance and anti-photoaging performance of the material.

[0114] The specific data of Test Example 2 are shown in Table 2

[0115] Test Example 3

[0116] The MPP single-wall corrugated pipes prepared in Example 2 and each comparative example were cut into samples with dimensions of 10 mm × 10 mm × 2.5 mm, and 3 parallel samples were prepared for each group of samples. Then the samples were respectively placed in containers filled with 600 mL of 15 mg / L methylene blue solution and subjected to photocatalytic reaction under specific light conditions for 500 h. Among them, the specific light conditions were: a xenon lamp with a power of 400 W was selected as the simulation light source, equipped with a narrow-band pass filter to accurately control the light wavelength range irradiated on the sample solution within 320 - 700 nm, and the light in the UV-C (<280 nm) band was filtered out, and the light intensity was set to 120 mW / cm 2During the reaction process, a magnetic stirrer was used to continuously stir the solution at a speed of 250 rpm to ensure that the solution was evenly irradiated and the photocatalyst was in full contact with methylene blue. After 500 h of photocatalytic reaction, instruments such as a spectrophotometer were used to detect the change in the absorbance of the methylene blue solution, and the change in the concentration of methylene blue was calculated according to the Lambert-Beer law, and then the degradation rate of methylene blue was obtained.

[0117] The degradation rate of methylene blue = [(initial concentration of methylene blue - concentration of methylene blue after reaction) / initial concentration of methylene blue]×100%.

[0118] The lower the value of the photocatalytic degradation rate, the weaker the photocatalytic degradation effect of the sample on methylene blue, the lower the degree of photocatalytic damage to the material itself, and the better the anti-aging performance.

[0119] The specific data of Test Example 2 are shown in Table 2

[0120] Table 2:

[0121] Sample Free radical scavenging rate Photocatalytic degradation rate (500 h) Example 2 92.3％±1.5 7.2％±0.8 Comparative Example 1 68.4％±2.7 43.6％±2.1 Comparative Example 2 79.6％±1.8 28.5％±1.7 Comparative Example 3 58.2％±3.4 52.3±2.9

[0122] As can be seen from Table 1: After 2000 h of aging test, the tensile strength retention rate of the MPP single-wall corrugated pipe in Example 2 reached 89.7%±1.2, the elongation at break retention rate was 83.5%±2.1, and the surface crack density was only 0.8±0.3 cracks / cm 2 In Comparative Example 1, an equal amount of anatase-type nano-titanium dioxide was used instead of the modified nano-titanium dioxide, and its tensile strength retention rate dropped sharply to 63.4%±2.8, the elongation at break retention rate was 51.2%±3.5, and the surface crack density was as high as 12.5±1.6 cracks / cm 2 This intuitively shows that unmodified nano-titanium dioxide cannot maintain the mechanical properties of the pipe like the "TiO2@SiO2 / ZnO" heterojunction structure by synergistically absorbing ultraviolet light and reducing photocatalytic damage. The generation of a large number of cracks causes serious performance deterioration. In Comparative Example 2, an equal amount of antioxidant 1010 was used instead of the microencapsulated antioxidant, and the tensile strength retention rate was 72.8%±1.9, the elongation at break retention rate was 65.3%±2.8, and the surface crack density was 6.3±0.9 cracks / cm 2 , indicating that ordinary antioxidants cannot achieve the synergistic protection of dynamic self-repair and free radical neutralization of microencapsulated antioxidants, and the effect is poor in preventing crack propagation and maintaining performance. In Comparative Example 3, both the modified nano-titanium dioxide and the microencapsulated antioxidant were replaced, and the tensile strength retention rate was as low as 54.1%±3.1, the elongation at break retention rate was 42.7%±4.2, and the surface crack density was as high as 18.9±2.3 cracks / cm 2 , highlighting the value of the synergistic effect of the two key components of the present invention in improving the mechanical property stability of the pipe.

[0123] As can be seen from Table 2, the free radical scavenging rate of the MPP single-wall corrugated pipe in Example 2 reached 92.3% ± 1.5, and the photocatalytic degradation rate was only 7.2% ± 0.8 at 500 h. For Comparative Example 1, the free radical scavenging rate was 68.4% ± 2.7, and the photocatalytic degradation rate was 43.6% ± 2.1. When the "TiO2@SiO2 / ZnO" heterojunction structure was lacking, it was difficult for the pipe material to effectively inhibit the photocatalytic reaction, a large amount of free radicals were generated and could not be efficiently scavenged. For Comparative Example 2, the free radical scavenging rate was 79.6% ± 1.8, and the photocatalytic degradation rate was 28.5% ± 1.7, indicating that ordinary antioxidants were far less effective than the synergistic effect of the microencapsulated antioxidant polyurea formaldehyde shell surface amino active adsorption protection and the release of antioxidants by microcapsule rupture in scavenging free radicals and inhibiting photocatalytic degradation. For Comparative Example 3, the free radical scavenging rate was 58.2% ± 3.4, and the photocatalytic degradation rate was 52.3 ± 2.9, which again confirmed the significant advantages of the present invention in free radical scavenging and reducing photocatalytic damage through unique structure and composition design.

[0124] In summary, through the comprehensive analysis of the data in Table 1 and Table 2, the "TiO 2 @SiO 2 / ZnO" heterojunction structure constructed by the modified nano-titanium dioxide and the introduction of microencapsulated antioxidants in the present invention have shown significant advantages in anti-ultraviolet, free radical scavenging, reducing photocatalytic damage, and improving the mechanical property stability of the pipe material.

[0125] The above is only a preferred embodiment of the present invention, and it does not impose any form of limitation on the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the above-disclosed technical content to obtain equivalent embodiments with equivalent changes within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. An anti-aging MPP single-wall corrugated pipe, characterized in that: The single-wall corrugated pipe is made of the following raw materials in parts by weight:

2. The anti-aging MPP single-wall corrugated pipe according to claim 1, characterized in that: The preparation method of the modified nano titanium dioxide specifically comprises the following steps: S1, mixing nano titanium dioxide, tetraethyl orthosilicate and zinc nitrate in a weight ratio of 100:(15-30):(2-8), and then adding them into an anhydrous ethanol solution for ultrasonic dispersion to form a uniform suspension; S2, adjusting the pH of the suspension to 9-11, coating the surface of the nano-titanium dioxide with an amorphous silicon dioxide layer by a sol-gel method, and simultaneously doping zinc oxide quantum dots into the silicon dioxide layer; S3. Calcinate at 600-800°C for 2-4 hours to obtain modified nano-sized titanium dioxide.

3. The anti-aging MPP single-wall corrugated pipe according to claim 2, characterized in that: The nano titanium dioxide is anatase type, the weight of the nano titanium dioxide is 100 parts, the weight of the ethyl orthosilicate is 15-30 parts, and the weight of the zinc nitrate is 2-8 parts.

4. The anti-aging MPP single-wall corrugated pipe according to claim 1, characterized in that: The invention also comprises a microencapsulated antioxidant, wherein the weight portion of the microencapsulated antioxidant is 0.3-1.2 parts.

5. The anti-aging MPP single-wall corrugated pipe according to claim 4, characterized in that: The microencapsulated antioxidant is composed of an antioxidant 1010 encapsulated by a polyurea formaldehyde shell.

6. The anti-aging MPP single-wall corrugated pipe according to claim 5, characterized in that: The surface of the polyurea formaldehyde shell layer of the microencapsulated antioxidant contains amino groups.

7. The anti-aging MPP single-wall corrugated pipe according to claim 6, characterized in that: The preparation method of the microencapsulated antioxidant specifically comprises the following steps: Y1. Dispersing antioxidant 1010 in water, adding urea and 37% formaldehyde solution, and stirring to form a prepolymer, wherein the weight ratio of antioxidant 1010, urea and 37% formaldehyde solution is 10:(8.4-12):(12.6-18); Y2. Adjust the pH of the prepolymer to 3-5, raise the temperature to 60-80°C, and react for 3-5 hours to perform in-situ polymerization; Y3, filter, wash and dry to obtain a microencapsulated antioxidant.

8. The method for preparing the anti-aging MPP single-wall corrugated pipe according to any one of claims 1 to 7, characterized in that: The following steps are involved: Z1. Premix the modified nano titanium dioxide, talcum powder and polypropylene resin in a high-speed mixer, control the temperature at 40-60°C and the speed at 1200-1500rpm; Z2, add toughening agent, defoaming agent and microencapsulated antioxidant, and continue mixing until uniform; Z3, melt blending and granulation through a twin-screw extruder, with the barrel temperature set at 180-220°C; Z4. Extrusion and shaping by single-wall corrugated pipe forming machine, die head temperature 190-210℃, cooling water temperature 10-25℃.

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