Antibacterial polypropylene noise reduction drain pipe and preparation method thereof

Abstract

The invention relates to the field of drain pipes, and discloses an antibacterial polypropylene noise-reduction drain pipe and a preparation method thereof, the antibacterial polypropylene noise-reduction drain pipe comprises polypropylene, modified glass fiber, an antibacterial additive, a compatilizer and a stabilizer; the modified glass fiber is prepared by performing formylation modification on glass fiber by using 3-aminopropyltriethoxysilane and glutaraldehyde, grafting triethylene tetramine and DOPO into a glass fiber structure, and then grafting a hindered phenol antioxidant; the antibacterial additive is prepared by compounding chitosan Schiff base and modified nano titanium dioxide, the chitosan Schiff base is prepared by utilizing a Schiff base reaction between chitosan and vanillin, and the modified nano titanium dioxide is prepared by utilizing isocyanate propyl triethoxy silane and ethyl glycolate to modify nano titanium dioxide. By adding the modified glass fiber and the antibacterial additive, the pipe is endowed with excellent heat resistance, aging resistance, flame retardance and antibacterial performance.

Description

Technical Field

[0001] The invention belongs to the technical field of drainage pipes, and particularly relates to an antibacterial polypropylene noise reduction drainage pipe and a preparation method thereof. Background Technique

[0002] Drainage pipes mainly undertake the tasks of draining rainwater, sewage, farmland irrigation, etc., and are one of the infrastructure of urban construction. Drainage pipes are mainly divided into plastic drainage pipes, concrete pipes and reinforced concrete pipes. Among them, plastic drainage pipes are widely used in the field of drainage pipes because of their light weight, smooth pipe wall, large flow capacity, good sealing performance, long service life, convenient transportation and installation, and fast construction speed.

[0003] Traditional drainage pipes are prone to generate large noises during the drainage process, destroying the quietness of the living room and seriously affecting the quality of daily life. Polypropylene, as a commonly used drainage pipe material, is a general thermoplastic with excellent comprehensive properties, having the advantages of light weight, high strength, chemical corrosion resistance, low cost, recyclability, etc. However, due to the presence of tertiary carbon atoms in the polypropylene material, it is very sensitive to heat and oxygen and is extremely prone to oxidation reactions, resulting in poor aging resistance of polypropylene. In addition, since polypropylene is a flammable polymer, the pipes made of polypropylene materials generally have the defect of poor flame retardancy. Moreover, with the long-term use of polypropylene drainage pipes, bacteria and microorganisms will adhere and grow on their inner surfaces, forming some substances similar to mucous membranes. When it deteriorates seriously, a large amount of scale impurities will be formed, which is difficult to wash clean by the natural pressure of water, seriously affecting the water quality. Summary of the Invention

[0004] To solve the deficiencies mentioned in the above background technique, the purpose of the present invention is to provide an antibacterial polypropylene noise reduction drainage pipe and a preparation method thereof. By adding modified glass fiber and antibacterial additive, the pipe is endowed with excellent heat resistance, aging resistance, flame retardancy and antibacterial properties.

[0005] The purpose of the present invention can be achieved through the following technical solutions: An antibacterial polypropylene noise reduction drainage pipe, comprising the following components in parts by weight: 70-90 parts of polypropylene, 4-8 parts of modified glass fiber, 5-10 parts of antibacterial additive, 10-15 parts of compatibilizer, 0.1-1 part of stabilizer; The modified glass fiber is prepared by subjecting glass fiber to aldehyde group modification with 3-aminopropyltriethoxysilane and glutaraldehyde, then grafting triethylenetetramine and DOPO into the glass fiber structure, and then grafting the hindered phenol antioxidant 3,5-di-tert-butyl-4-hydroxybenzoic acid; the antibacterial additive is prepared by compounding chitosan Schiff base and modified nano-titanium dioxide, wherein the chitosan Schiff base is prepared by the Schiff base reaction between chitosan and vanillin, and the modified nano-titanium dioxide is prepared by modifying nano-titanium dioxide with isocyanatopropyltriethoxysilane and ethyl glycolate.

[0006] Preferably, the compatibilizer is one or a combination of two of maleic anhydride grafted ethylene octene copolymer and maleic anhydride grafted polyethylene.

[0007] Preferably, the stabilizer is one or a combination of multiple of zinc stearate, sodium stearate, and calcium stearate.

[0008] Preferably, the preparation method of the modified glass fiber includes the following steps: A. Place the glass fiber in an acetone solution for ultrasonic treatment and soak overnight. After drying, soak it in a mixed solution of concentrated sulfuric acid and hydrogen peroxide and stir for 7 - 12 h. Then filter it out and dry it in an oven to obtain pretreated glass fiber; B. Immerse the pretreated glass fiber in a toluene solution of 3 - aminopropyltriethoxysilane, place it at 100 - 115 °C for condensation reflux for 8 - 12 h, then wash it repeatedly with toluene and dry it to obtain amino - functionalized glass fiber. Take the amino - functionalized glass fiber and add it to a glutaraldehyde solution, place it at 40 - 55 °C and stir for reaction for 4 - 6 h. After the reaction is completed, centrifuge, wash, and dry it to obtain aldehyde - functionalized glass fiber; C. Take the aldehyde - functionalized glass fiber, triethylenetetramine, and DOPO in a reactor, add an ethanol solvent, place it at 75 - 85 °C for reaction for 20 - 30 min. After the reaction is completed, filter, wash, and dry it to obtain flame - retardant glass fiber; D. Take 3,5 - di - tert - butyl - 4 - hydroxybenzoic acid and chloroform in a reactor, place it at 45 - 60 °C and stir to mix, then add thionyl chloride and react for 4 - 6 h. After the reaction is completed, perform rotary evaporation to obtain 3,5 - di - tert - butyl - 4 - hydroxybenzoyl chloride; E. Take the flame - retardant glass fiber, add it to toluene for ultrasonic dispersion, add 3,5 - di - tert - butyl - 4 - hydroxybenzoyl chloride and triethylamine in a nitrogen atmosphere, place it at 55 - 70 °C and stir for reaction for 12 - 18 h. After the reaction is completed, perform suction filtration, wash, and dry it to obtain modified glass fiber.

[0009] Preferably, the mass ratio of the aldehyde - functionalized glass fiber, triethylenetetramine, and DOPO in step C is 2 - 3.5:1:1.47 - 1.85.

[0010] Preferably, the preparation method of the antibacterial additive includes the following steps: (1) Dissolve chitosan in acetic acid, add absolute ethanol and vanillin and stir to mix. Place it at 55 - 70 °C for reflux reaction for 18 - 24 h. After the reaction is completed, cool it to room temperature, add a sodium hydroxide solution to adjust the pH value of the system to neutral. The precipitate is subjected to suction filtration, washing, and drying to obtain chitosan Schiff base; (2) Take isocyanatopropyltriethoxysilane, ethyl glycolate and dibutyltin dilaurate in a reactor, place it at 35-45 °C and stir for 3-4 h. Then add nano-titanium dioxide, absolute ethanol and deionized water and disperse them evenly by ultrasonic wave. Add sodium hydroxide solution to adjust the pH value of the system to 9-10, place it at 55-70 °C and stir for 10-12 h. After the reaction is completed, filter, wash and dry to prepare modified nano-titanium dioxide; (3) Take chitosan Schiff base in deionized water, add acetic acid to adjust the pH value of the solution to 5.5-6, then add modified nano-titanium dioxide and disperse it evenly by ultrasonic wave. Place it at 40-50 °C and stir for 2-4 h. After the reaction is completed, filter, wash and dry to prepare the antibacterial additive.

[0011] Preferably, in the step (2), the molar ratio of isocyanatopropyltriethoxysilane to ethyl glycolate is 1:1-1.05.

[0012] Preferably, in the step (3), the mass ratio of chitosan Schiff base to modified nano-titanium dioxide is 1:2-4.

[0013] A preparation method of an antibacterial polypropylene noise reduction drainage pipe includes the following steps: Take parts by weight of polypropylene, modified glass fiber, antibacterial additive, compatibilizer and stabilizer, mix and disperse them to obtain a mixture, then extrude and pelletize. Add the prepared pellets into an injection molding machine for plasticization to prepare the antibacterial polypropylene noise reduction drainage pipe.

[0014] Preferably, the barrel temperature of the injection molding machine is set at 170-220 °C, and the mold temperature is set at 40-60 °C.

[0015] The beneficial effects of the present invention: The present invention first pretreats glass fibers to fully expose the silanol groups on their surfaces, and aldehyde group modification of the pretreated glass fibers is carried out using 3-aminopropyltriethoxysilane and glutaraldehyde. Then, triethylenetetramine and DOPO are grafted into the glass fiber structure through Schiff base reaction and DOPO addition reaction, thereby preparing flame-retardant glass fibers rich in nitrogen and phosphorus elements. At the same time, in the present invention, the carboxyl end of 3,5-di-tert-butyl-4-hydroxybenzoic acid is activated to form an acyl chloride structure and then reacts with the amino group at the other end of the flame-retardant glass fiber, and a hindered phenol antioxidant is further grafted into the flame-retardant glass fiber structure through a strong chemical bond, preparing modified glass fibers, avoiding physical losses caused by migration and volatilization of the flame-retardant component and the hindered phenol antioxidant, ensuring that the pipe achieves long-term flame retardancy and antioxidant effects. In addition, glass fibers have characteristics such as high strength, high temperature resistance, and chemical corrosion resistance, and they have a loose structure, enabling air to flow between the structures and having certain sound absorption characteristics. The modified glass fibers are beneficial to their dispersion in the matrix, and to a certain extent, avoid performance defects caused by glass fiber agglomeration.

[0016] The present invention prepares chitosan Schiff base by the Schiff base reaction between chitosan and vanillin. The Schiff base, as an antibacterial functional group, has biological activities such as antibacterial, bactericidal, and antiviral effects, enhancing the antibacterial effect of chitosan. At the same time, in the present invention, the isocyanate group at one end of isocyanatopropyltriethoxysilane reacts with the hydroxyl group in the ethyl glycolate structure to form a carbamate group, and the silanol groups at the other end of isocyanatopropyltriethoxysilane undergo dehydration condensation to form an oligomeric siloxane, and then a condensation reaction occurs with the hydroxyl groups on the surface of nano-titanium dioxide, thereby forming a coating on the surface of nano-titanium dioxide, preparing modified nano-titanium dioxide, improving the dispersion of nano-titanium dioxide in the matrix, being beneficial to the full exertion of its performance, and the formed siloxane can provide good heat resistance for the pipe. Then, chitosan Schiff base and modified nano-titanium dioxide are compounded to prepare an antibacterial additive. The three-dimensional network structure formed by the intermolecular and intramolecular hydrogen bond interactions of chitosan Schiff base restricts the movement of modified nano-titanium dioxide. At the same time, there is a hydrogen bond interaction between chitosan Schiff base and modified nano-titanium dioxide, improving the antibacterial performance while improving the dispersion of nano-titanium dioxide. Detailed implementation manners

[0017] The following will combine the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0018] Example 1 A preparation method of modified glass fibers includes the following steps: A. Take 10 g of glass fiber, place it in an acetone solution, ultrasonicate and soak it overnight. After drying, soak it in a mixed solution of concentrated sulfuric acid and hydrogen peroxide with a volume ratio of 7:3, stir for 10 h, then filter it out and dry it in an oven to obtain pretreated glass fiber; B. Immerse the pretreated glass fiber in a toluene solution of 10% 3-aminopropyltriethoxysilane, place it under reflux condensation at 110 °C for 9 h, then repeatedly wash it with toluene and dry it to obtain amino-functionalized glass fiber. Take 5 g of amino-functionalized glass fiber, add it to 250 mL of 7% glutaraldehyde solution, place it under stirring reaction at 50 °C for 6 h. After the reaction is completed, centrifuge, wash, and dry it to obtain aldehyde-functionalized glass fiber; C. Take 5 g of aldehyde-functionalized glass fiber, 1.46 g of triethylenetetramine, and 2.16 g of DOPO in a reactor, add 70 mL of ethanol solvent, place it under reaction at 80 °C for 25 min. After the reaction is completed, filter, wash, and dry it to obtain flame-retardant glass fiber; D. Take 3.2 g of 3,5-di-tert-butyl-4-hydroxybenzoic acid and 30 mL of chloroform in a reactor, place it under stirring and mixing at 55 °C, then add 5 mL of thionyl chloride and react for 4 h. After the reaction is completed, perform rotary evaporation to obtain 3,5-di-tert-butyl-4-hydroxybenzoyl chloride; E. Take 5 g of flame-retardant glass fiber, add it to 120 mL of toluene for ultrasonic dispersion, add 2.6 g of 3,5-di-tert-butyl-4-hydroxybenzoyl chloride and 5 mL of triethylamine in a nitrogen atmosphere, place it under stirring reaction at 60 °C for 14 h. After the reaction is completed, perform suction filtration, wash, and dry it to obtain modified glass fiber.

[0019] Example 2 A preparation method of an antibacterial additive includes the following steps: (1) Dissolve 2 g of chitosan in 120 mL of acetic acid with a volume fraction of 10%, add 40 mL of absolute ethanol and 14.6 g of vanillin, stir and mix, place it under reflux reaction at 60 °C for 20 h. After the reaction is completed, cool it to room temperature, add 0.5 mol / L sodium hydroxide solution to adjust the pH value of the system to neutral. The precipitate is subjected to suction filtration, washing, and drying to obtain chitosan Schiff base; (2) Take 4.95 g of isocyanatopropyltriethoxysilane, 2.09 g of ethyl glycolate, and 0.04 mL of dibutyltin dilaurate in a reactor, place it under stirring reaction at 40 °C for 4 h, then add 2 g of nano-titanium dioxide, 135 mL of absolute ethanol, and 65 mL of deionized water, ultrasonically disperse them evenly, add sodium hydroxide solution to adjust the pH value of the system to 10, place it under stirring reaction at 60 °C for 12 h. After the reaction is completed, perform suction filtration, washing, and drying to obtain modified nano-titanium dioxide; (3) Take 0.5 g of chitosan Schiff base in 120 mL of deionized water, add acetic acid to adjust the pH value of the solution to 5.5, then add 2 g of modified nano-titanium dioxide and disperse it evenly by ultrasonic treatment. Place it at 45 °C and stir for 3 h. After the reaction is completed, filter, wash, and dry to prepare an antibacterial additive.

[0020] Example 3 An antibacterial polypropylene noise-reducing drain pipe, comprising the following components in parts by weight: 72 parts of polypropylene, 4 parts of the modified glass fiber prepared in Example 1, 5 parts of the antibacterial additive prepared in Example 2, 10 parts of compatibilizer maleic anhydride grafted ethylene octene copolymer, 0.3 part of stabilizer zinc stearate.

[0021] The preparation method of the above antibacterial polypropylene noise-reducing drain pipe comprises the following steps: Take polypropylene, modified glass fiber, antibacterial additive, compatibilizer and stabilizer in parts by weight, mix and disperse to obtain a mixture, then extrude and pelletize. Add the prepared pellets into an injection molding machine for plasticization. The barrel temperature of the injection molding machine is set at 180 °C, and the mold temperature is set at 50 °C to prepare an antibacterial polypropylene noise-reducing drain pipe.

[0022] Example 4 An antibacterial polypropylene noise-reducing drain pipe, comprising the following components in parts by weight: 80 parts of polypropylene, 6 parts of the modified glass fiber prepared in Example 1, 7 parts of the antibacterial additive prepared in Example 2, 12 parts of compatibilizer maleic anhydride grafted polyethylene, 0.5 part of stabilizer calcium stearate.

[0023] The preparation method of the above antibacterial polypropylene noise-reducing drain pipe is the same as that of Example 3.

[0024] Example 5 An antibacterial polypropylene noise-reducing drain pipe, comprising the following components in parts by weight: 88 parts of polypropylene, 8 parts of the modified glass fiber prepared in Example 1, 10 parts of the antibacterial additive prepared in Example 2, 14 parts of compatibilizer maleic anhydride grafted ethylene octene copolymer, 1 part of stabilizer sodium stearate.

[0025] The preparation method of the above antibacterial polypropylene noise-reducing drain pipe is the same as that of Example 3.

[0026] Comparative Example 1 An antibacterial polypropylene noise-reducing drain pipe, comprising the following components in parts by weight: 88 parts of polypropylene, 8 parts of glass fiber, 10 parts of the antibacterial additive prepared in Example 2, 14 parts of compatibilizer maleic anhydride grafted ethylene octene copolymer, 1 part of stabilizer sodium stearate.

[0027] The preparation method of the above antibacterial polypropylene noise-reducing drain pipe is the same as that of Example 3.

[0028] Comparative Example 2 An antibacterial polypropylene noise-reducing drain pipe, comprising the following components in parts by weight: 88 parts of polypropylene, 8 parts of the modified glass fiber prepared in Example 1, 10 parts of the chitosan Schiff base prepared in Example 2, 14 parts of the compatibilizer maleic anhydride grafted ethylene-octene copolymer, and 1 part of the stabilizer sodium stearate.

[0029] The preparation method of the above antibacterial polypropylene noise-reducing drain pipe is the same as that of Example 3.

[0030] Comparative Example 3 An antibacterial polypropylene noise-reducing drain pipe, comprising the following components in parts by weight: 88 parts of polypropylene, 8 parts of the modified glass fiber prepared in Example 1, 10 parts of nano-titanium dioxide, 14 parts of the compatibilizer maleic anhydride grafted ethylene-octene copolymer, and 1 part of the stabilizer sodium stearate.

[0031] The preparation method of the above antibacterial polypropylene noise-reducing drain pipe is the same as that of Example 3.

[0032] Performance Testing Perform performance testing on the drain pipes prepared in Examples 3-5 and Comparative Examples 1-3: Use a universal testing machine to conduct tensile property testing according to the GB / T 1040.2-2022 standard, and test the change rates of tensile strength and elongation at break after aging at 100 °C for 168 h; Refer to GB / T 2406.2-2009 to test the limiting oxygen index of the sample to evaluate the flame retardant performance of the sample; Place the sample in a TGA-103 thermogravimetric analyzer, under nitrogen protection, with a heating rate of 5 °C / min, raise the temperature from room temperature to 800 °C, and record the initial decomposition temperature of the material; The concentration of 10 7 CFU / mL of Staphylococcus aureus bacterial solution and Escherichia coli bacterial solution were smeared on the surface of the pipe, covered with a sterile PE film, left for 1 h, the pipe was rinsed with phosphate buffer solution, the rinsing solution was smeared in the culture medium and cultured for 24 h, the number of colonies was counted, the antibacterial rate was calculated, and the antibacterial performance of the sample was evaluated. The data results are shown in Table 1.

[0033] Table 1 Test Results of Specimen Performance

[0034] It can be seen from the data results in Table 1 that the pipes prepared in Examples 3-5 of the present invention have high tensile strength, are not easily broken, have good heat resistance, and have excellent aging resistance, antibacterial and flame retardant properties.

[0035] In Comparative Example 1, the glass fiber was not modified. The measured tensile properties were slightly worse than those of Examples 3-5. This might be due to the agglomeration of the glass fiber, which led to a decrease in its mechanical properties. The change rates of the tensile strength and the elongation at break were significantly different from those of Examples 3-5. Moreover, its limiting oxygen index and initial thermal decomposition temperature were lower than those of Examples 3-5 because nitrogen and phosphorus elements were not introduced into the glass fiber structure and a hindered phenol antioxidant was not grafted.

[0036] In Comparative Example 2, the antibacterial additive was replaced with chitosan Schiff base in equal amounts. The measured tensile properties, antibacterial rate, and initial thermal decomposition temperature were lower than those of Examples 3-5, indicating that the addition of the modified nano-titanium dioxide could improve the mechanical properties, antibacterial properties, and heat resistance of the pipe.

[0037] In Comparative Example 3, the antibacterial additive was replaced with nano-titanium dioxide in equal amounts. The measured tensile properties were slightly worse than those of Examples 3-5 because the agglomeration of nano-silica led to a decrease in its mechanical properties. The initial thermal decomposition temperature was lower than that of Examples 3-5 because an oligomeric siloxane was not coated on the surface of the nano-titanium dioxide. Moreover, its antibacterial rate decreased significantly compared with that of Examples 3-5, indicating that the addition of chitosan Schiff base could improve the antibacterial properties of the pipe.

[0038] In the description of this specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0039] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and all these changes and improvements fall within the scope of the present invention claimed.

Claims

1. An antibacterial polypropylene noise reduction drainage pipe, characterized in that: The invention comprises the following components in parts by weight: 70-90 parts of polypropylene, 4-8 parts of modified glass fiber, 5-10 parts of antibacterial additive, 10-15 parts of compatibilizer and 0.1-1 part of stabilizer; The modified glass fiber is prepared by using 3-aminopropyltriethoxysilane and glutaraldehyde to formaldehyde-modify the glass fiber, then grafting triethylenetetramine and DOPO into the glass fiber structure, and then grafting hindered phenol antioxidant 3,5-di-tert-butyl-4-hydroxybenzoic acid; the antibacterial additive is prepared by compounding chitosan Schiff base and modified nano titanium dioxide, wherein the chitosan Schiff base is prepared by using the Schiff base reaction between chitosan and vanillin, and the modified nano titanium dioxide is prepared by modifying nano titanium dioxide using isocyanatepropyltriethoxysilane and ethyl glycolate.

2. The antibacterial polypropylene noise reduction drainage pipe according to claim 1, characterized in that: The compatibilizer is one or a combination of maleic anhydride grafted ethylene octene copolymer and maleic anhydride grafted polyethylene.

3. The antibacterial polypropylene noise reduction drainage pipe according to claim 1, characterized in that: The stabilizer is one or more combinations of zinc stearate, sodium stearate and calcium stearate.

4. The antibacterial polypropylene noise reduction drainage pipe according to claim 1, characterized in that: The preparation method of the modified glass fiber comprises the following steps: A. Place the glass fiber in an acetone solution for ultrasonic treatment and soak overnight. After drying, soak it in a mixed solution of concentrated sulfuric acid and hydrogen peroxide and stir for 7 to 12 hours. Then filter it out and dry it in an oven to prepare pretreated glass fiber. B. Taking the pretreated glass fiber and immersing it in a toluene solution of 3-aminopropyltriethoxysilane, placing it at 100-115° C. and condensing and reflux for 8-12 hours, then washing it repeatedly with toluene and drying it to obtain an amino glass fiber, taking the amino glass fiber and adding glutaraldehyde solution, placing it at 40-55° C. and stirring for reaction for 4-6 hours, and after the reaction is completed, centrifuging, washing, and drying it to prepare an aldehyde-modified glass fiber; C. Take the formaldehyde-modified glass fiber, triethylenetetramine and DOPO in a reactor, add ethanol solvent, and react at 75-85° C. for 20-30 minutes. After the reaction is completed, filter, wash and dry to prepare a flame-retardant glass fiber; D. Take 3,5-di-tert-butyl-4-hydroxybenzoic acid and chloroform in a reactor, stir and mix at 45-60°C, then add thionyl chloride to react for 4-6 hours, and after the reaction is completed, rotary evaporate to prepare 3,5-di-tert-butyl-4-hydroxybenzoyl chloride; E. Take flame-retardant glass fiber and add toluene for ultrasonic dispersion. Add 3,5-di-tert-butyl-4-hydroxybenzoyl chloride and triethylamine in a nitrogen atmosphere. Stir and react at 55-70°C for 12-18h. After the reaction is completed, filter, wash and dry to prepare modified glass fiber.

5. The antibacterial polypropylene noise reduction drainage pipe according to claim 4, characterized in that: In the step C, the mass ratio of the formaldehyde-modified glass fiber, triethylenetetramine and DOPO is 2-3.5:1:1.47-1.

85.

6. The antibacterial polypropylene noise reduction drainage pipe according to claim 1, characterized in that: The preparation method of the antibacterial additive comprises the following steps: (1) Chitosan is dissolved in acetic acid, anhydrous ethanol and vanillin are added, stirred and mixed, and refluxed at 55-70°C for 18-24 hours. After the reaction is completed, the mixture is cooled to room temperature, and a sodium hydroxide solution is added to adjust the pH value of the system to neutral. The precipitate is filtered, washed and dried to prepare a chitosan Schiff base; (2) Propyl triethoxysilane, ethyl glycolate and dibutyltin dilaurate were placed in a reactor, stirred and reacted at 35-45°C for 3-4 hours, then nano-titanium dioxide, anhydrous ethanol and deionized water were added and ultrasonically dispersed uniformly, sodium hydroxide solution was added to adjust the pH value of the system to 9-10, and the reaction was stirred and reacted at 55-70°C for 10-12 hours. After the reaction was completed, the modified nano-titanium dioxide was prepared by filtration, washing and drying; (3) Take chitosan Schiff base and dissolve it in deionized water, add acetic acid to adjust the pH value of the solution to 5.5-6, then add modified nano-titanium dioxide and disperse it evenly by ultrasonication, place it at 40-50 °C and stir to react for 2-4 hours. After the reaction is completed, filter, wash and dry to prepare the antibacterial additive.

7. The antibacterial polypropylene noise reduction drainage pipe according to claim 6, characterized in that: In the step (2), the molar ratio of isocyanatepropyltriethoxysilane to ethyl glycolate is 1:1-1.

05.

8. The antibacterial polypropylene noise reduction drainage pipe according to claim 6, characterized in that: In the step (3), the mass ratio of chitosan Schiff base to modified nano-titanium dioxide is 1:2-4.

9. A method for preparing an antibacterial polypropylene noise reduction drainage pipe according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: taking parts by weight of polypropylene, modified glass fiber, antibacterial additive, compatibilizer and stabilizer, mixing and dispersing to obtain a mixture, then extruding and granulating the mixture, adding the prepared granules into an injection molding machine for plasticization, and preparing an antibacterial polypropylene noise reduction drainage pipe.

10. The method for preparing the antibacterial polypropylene noise reduction drainage pipe according to claim 9, characterized in that: The barrel temperature of the injection molding machine is set to 170-220°C, and the mold temperature is set to 40-60°C.

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