An antibacterial polyolefin composite pipe and a method for manufacturing the same

Abstract

The application discloses an antibacterial polyolefin composite pipe and a preparation method thereof, and belongs to the technical field of polymer pipes. The antibacterial polyolefin composite pipe comprises an inner layer and an outer layer, and the inner layer comprises the following components in parts by mass: 88-95 parts of random copolymerized polypropylene, 3-6 parts of an antibacterial agent, 3-6 parts of a compatilizer, and 0.1-1 parts of an antioxidant. The antibacterial agent comprises silver ions and an antibacterial carrier, and the antibacterial carrier comprises sulfonated graphene oxide and a metal imidazole acid salt skeleton. The antibacterial agent is introduced into the inner layer, the antibacterial agent is compounded by the antibacterial carrier and the silver ions, the precipitation of silver can be effectively slowed down, the initial antibacterial effect of the polyolefin composite pipe is ensured, the antibacterial durability of the polyolefin composite pipe is improved, the growth of bacteria and other microorganisms can be effectively inhibited under the actual working condition of tap water, the hygiene and cleanness of the pipe interior are ensured, and therefore the pipeline system of the polyolefin composite pipe is suitable for long-term conveying of drinking water.

Description

Technical Field

[0001] This invention belongs to the field of polymer pipe technology, and particularly relates to an antibacterial polyolefin composite pipe and its preparation method. Background Technology

[0002] In today's rapidly developing urbanization process, the stable supply of water resources and water quality safety have become a focus of social concern. As an important component of modern buildings and infrastructure, pipeline systems bear the heavy responsibility of delivering clean drinking water.

[0003] PP-R pipe is short for random copolymer polypropylene pipe, a random copolymer of propylene and another olefin monomer. Due to the irregular distribution of its comonomers and polypropylene chains, the molecular structure of polypropylene is altered, giving PP-R pipes superior physical and chemical properties. PP-R pipes are lightweight, corrosion-resistant, have a smooth, scale-free inner wall, are easy to install and maintain, and have a long service life. They are currently widely used in building water supply and drainage, urban and rural drainage, and municipal engineering, and have rapidly gained market acceptance. However, in actual water supply use, with long-term use, it has been found that bacteria and other microorganisms adhere to and proliferate on the inner surface of PP-R pipes, forming a mucus-like substance. In severe cases, large amounts of scale and impurities can form, which are difficult to clean with natural water pressure, seriously affecting water quality and ultimately rendering them unusable.

[0004] Therefore, there is an urgent need to develop a polyolefin composite pipe with antibacterial properties. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an antibacterial polyolefin composite pipe and its preparation method. The polyolefin composite pipe has a good antibacterial effect. Under the actual working conditions of tap water, the pipe system can effectively inhibit the growth of bacteria and other microorganisms, reduce scale and impurities, and ensure the hygiene and cleanliness of the inside of the pipe.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides a chlorinated polyolefin composite pipe, comprising an inner layer and an outer layer. The inner layer comprises the following components in parts by weight: 88-95 parts of random copolymer polypropylene, 3-6 parts of antibacterial agent, 3-6 parts of compatibilizer, and 0.1-1 parts of antioxidant. The antibacterial agent comprises silver ions and an antibacterial carrier, wherein the mass percentage of the silver ions to the antibacterial carrier is not less than 0.5%, and the antibacterial carrier comprises sulfonated graphene oxide and a metal imidazolate backbone, wherein the mass ratio of the sulfonated graphene oxide to the metal imidazolate backbone is 1:(2-8).

[0008] The outer layer is made of random copolymer polypropylene.

[0009] The antibacterial polyolefin composite pipe provided by this invention introduces an antibacterial agent into the inner layer. This antibacterial agent uses a compound of sulfonated graphene oxide and a metal imidazolate skeleton as an antibacterial carrier. This antibacterial carrier, when compounded with silver ions, can effectively slow down the precipitation of silver. While ensuring the initial antibacterial effect of the polyolefin composite pipe, it also improves the antibacterial durability of the polyolefin composite pipe. Under the actual working conditions of tap water, it can effectively inhibit the growth of bacteria and other microorganisms, reduce scale and impurities, and ensure the hygiene and cleanliness of the inside of the pipe. Therefore, the pipeline system of the polyolefin composite pipe is suitable for long-term transportation of drinking water.

[0010] Metallic imidazolate frameworks (ZIFs) possess abundant porous structures, providing numerous adsorption sites and channels, thus immobilizing silver ions within their structure through ion exchange. Sulfonated graphene oxide, with its large specific surface area and excellent chemical stability, provides favorable attachment sites for ZIFs and interacts with them via hydrogen and coordination bonds. The synergistic effect of silver ions, sulfonated graphene oxide, and the metallic imidazolate framework enhances the initial antibacterial properties of polyolefin composite pipes. By enhancing the sustained-release effect and controlling the silver ion release rate, the antibacterial durability of the pipes is improved while maintaining their hygienic properties.

[0011] Sulfonated graphene oxide contains a large number of sulfonic acid functional groups, which can effectively improve the dispersibility and thermal stability of antibacterial agents, thereby improving the processing stability of pipes. The combination of sulfonated graphene oxide and metal imidazolium salt framework gives the antibacterial carrier a unique layered structure and extremely low interlayer shear strength. The introduction of this antibacterial carrier can significantly reduce the friction coefficient of the inner layer system, improve the melt flowability and processability of the inner layer system, reduce the shear peak during extrusion processing, improve the quality of pipes, and thus ensure the mechanical properties of pipes.

[0012] For example, in the inner layer, the mass fraction of the random copolymer polypropylene can be 88 parts, 89 parts, 90 parts, 91 parts, 92 parts, 93 parts, 94 parts, 95 parts, or any two sets of values ​​therein; the mass fraction of the antibacterial agent can be 3 parts, 4 parts, 5 parts, 6 parts, or any two sets of values ​​therein; the mass fraction of the compatibilizer can be 3 parts, 4 parts, 5 parts, 6 parts, or any two sets of values ​​therein; and the mass fraction of the antioxidant can be 0.1 parts, 0.3 parts, 0.5 parts, 0.8 parts, 1 part, or any two sets of values ​​therein.

[0013] For example, the mass ratio of the sulfonated graphene oxide to the metal imidazole backbone can be 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, or any two of these mass ratios.

[0014] Preferably, the outer layer comprises the following components in parts by weight: 98-99 parts of random copolymer polypropylene, 1-2 parts of compatibilizer, and 0.1-1 parts of antioxidant.

[0015] Preferably, the inner layer comprises the following components in parts by weight: 90-95 parts of random copolymer polypropylene, 4-5 parts of antibacterial agent, 4-5 parts of compatibilizer, and 0.1-1 parts of antioxidant.

[0016] Preferably, the mass percentage of the silver ions in the antibacterial carrier is 0.5% to 8%. For example, the mass percentage of the silver ions in the antibacterial carrier can be 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, or any two of these ranges.

[0017] More preferably, the mass percentage of the silver ions to the mass of the antibacterial carrier is 2-8%.

[0018] Preferably, the mass ratio of the sulfonated graphene oxide to the metal imidazolate skeleton is 1:(4~6). When the mass ratio of the sulfonated graphene oxide to the metal imidazolate skeleton is within the above-mentioned preferred range, the overall performance of the polyolefin composite pipe is better.

[0019] Preferably, the antibacterial carrier is prepared by the following method:

[0020] Sulfonated graphene oxide, methanol, and soluble zinc salt were mixed, and then 2-methylimidazole was added to carry out the mixing reaction. After filtration, washing, drying, and grinding, the antibacterial carrier was obtained.

[0021] In the above mixed reaction process, the nitrogen atom (N) in the 2-methylimidazolium molecule serves as a coordination site, forming an imidazolium group through deprotonation, which then forms a coordination bond with the zinc ions of the soluble zinc salt, thereby generating a metal imidazolium salt skeleton.

[0022] More preferably, the mass ratio of the sulfonated graphene oxide, the soluble zinc salt, and the 2-methylimidazole is sulfonated graphene oxide: soluble zinc salt: 2-methylimidazole = (0.2~0.6): 1: 2.

[0023] For example, the mass ratio of the sulfonated graphene oxide, soluble zinc salt and 2-methylimidazole can be 0.2:1:2, 0.3:1:2, 0.4:1:2, 0.5:1:2, 0.6:1:2 or any two of these mass ratios.

[0024] More preferably, the soluble zinc salt includes at least one of zinc nitrate and zinc chloride.

[0025] More preferably, the conditions for the mixing reaction are: stirring speed of 100~500 r / min and reaction time of 2~4 h.

[0026] More preferably, the ratio of the mass of the sulfonated graphene oxide to the volume of methanol is (3~4) g: 10 mL.

[0027] More preferably, the step of mixing the sulfonated graphene oxide, methanol and soluble zinc salt is as follows: after mixing the sulfonated graphene oxide and methanol, ultrasonically disperse them for 3-5 hours, and then add the soluble zinc salt and stir and disperse for 0.5-2 hours.

[0028] Preferably, the sulfonated graphene oxide is prepared by the following method:

[0029] Graphene oxide, water, and azobenzenesulfonic acid are mixed and reacted at 0-5°C for 2-4 hours. After centrifugation, the sulfonated graphene oxide is obtained. The mass ratio of graphene oxide to azobenzenesulfonic acid is 1:(2-4).

[0030] More preferably, the preparation method of the graphene oxide includes the following steps: after mixing sulfuric acid solution and graphite powder, stirring and mixing at 0~5℃ for 1~3h, then adding potassium permanganate, heating to 20~30℃ and adding water, then heating to 90~100℃ and stirring for 2~4h, cooling to 20~30℃ and adding hydrogen peroxide solution and mixing, and then filtering, washing and drying to obtain graphene oxide.

[0031] More preferably, the mass ratio of the sulfuric acid solution to the graphite powder is (4~6):1, the mass ratio of the potassium permanganate to the graphite powder is (1.5~3):1, the mass ratio of the water to the graphite powder is (20~40):1, the mass ratio of the hydrogen peroxide to the graphite powder is (0.5~1):1, the hydrogen peroxide in the hydrogen peroxide has a mass percentage content of 25~30%, and the sulfuric acid in the sulfuric acid solution has a mass concentration of 95~98%.

[0032] Preferably, the method for preparing the antibacterial agent includes the following steps: sulfonated graphene oxide and a metal imidazole acid backbone are compounded, mixed with water and silver nitrate, and ultrasonically dispersed, then filtered, washed, and dried to obtain the antibacterial agent.

[0033] Preferably, the density of the random copolymer polypropylene is 0.895~0.915 g / cm³. 3 The random copolymer polypropylene has a melt flow rate of 0.2~0.5 g / 10 min at 190℃ and 2.16 kg load.

[0034] Preferably, the antioxidant includes at least one of hindered phenolic antioxidants and phosphite antioxidants, wherein the hindered phenolic antioxidant includes at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,6-di-tert-butyl-p-cresol, and bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine, and the phosphite antioxidant includes at least one of triphenyl phosphite and tributyl sulfite.

[0035] Preferably, the compatibilizer comprises polypropylene grafted maleic anhydride, wherein the density of the polypropylene grafted maleic anhydride is 0.9~1.0 g / cm³. 3 The melt flow rate is 5~10g / 10min, and the grafting rate of maleic anhydride is 1~1.5%.

[0036] Preferably, the thickness of the inner layer accounts for no less than 30% of the total thickness of the antibacterial polyolefin composite pipe.

[0037] More preferably, the thickness of the inner layer accounts for 30-80% of the total thickness of the antibacterial polyolefin composite pipe.

[0038] Secondly, the present invention provides a method for preparing an antibacterial polyolefin composite pipe as described in the first aspect, comprising the following steps:

[0039] S1. The components of the inner layer are mixed and then extruded and granulated to obtain the inner layer material; the components of the outer layer are mixed and then extruded and granulated to obtain the outer layer material.

[0040] S2. The inner and outer layer materials are co-extruded, vacuumed and sized, cooled, drawn, and cut to obtain antibacterial polyolefin composite pipes.

[0041] Preferably, in step S1, the extrusion granulation temperature is 170~190℃, and the screw speed of the extrusion granulation is 100~120r / min.

[0042] Preferably, in step S2, the temperature of the co-extrusion is 190~210℃, and the screw speed of the co-extrusion is 30~100r / min.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0044] The antibacterial polyolefin composite pipe provided by this invention introduces an antibacterial agent into the inner layer. This antibacterial agent uses a compound of sulfonated graphene oxide and a metal imidazolate skeleton as an antibacterial carrier. This antibacterial carrier, when compounded with silver ions, can effectively slow down the precipitation of silver. While ensuring the initial antibacterial effect of the polyolefin composite pipe, it also improves the antibacterial durability of the polyolefin composite pipe. Under the actual working conditions of tap water, it can effectively inhibit the growth of bacteria and other microorganisms, reduce scale and impurities, and ensure the hygiene and cleanliness of the inside of the pipe. Therefore, the pipeline system of the polyolefin composite pipe is suitable for long-term transportation of drinking water. Detailed Implementation

[0045] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0046] Unless otherwise specified, the reagents, methods and equipment used in this invention are all conventional reagents, methods and equipment in the field.

[0047] Unless otherwise specified, the components used in the parallel experiments of the embodiments and comparative examples of this invention are from the same source.

[0048] The raw materials used in this invention are as follows:

[0049] Random copolymer polypropylene: grade 4220, manufactured by Beijing Yanshan Branch of China Petroleum & Chemical Corporation, density 0.895 g / cm³ 3 According to GB / T 3682-2000, the melt flow rate at 230℃ and 2.16kg load was 0.23g / 10min.

[0050] Compatibilizer: Polypropylene grafted with maleic anhydride, brand name 18722 SK, manufactured by Comprehensive Chemicals, density 0.900 g / cm³ 3 According to GB / T 3682-2000, the melt flow rate at 230℃ and 2.16kg load was 7.0g / 10min, and the grafting rate of maleic anhydride was 1.3%.

[0051] Graphite powder: manufactured by Changzhou Sixth Element Co., Ltd.

[0052] Antioxidant: Pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and 2,6-di-tert-butyl-p-cresol were mixed in a 1:1 mass ratio;

[0053] Antibacterial agent 1: Self-made, its preparation method is as follows:

[0054] (1) Preparation of graphene oxide: Sulfuric acid solution was added to a beaker containing graphite powder, with a mass ratio of sulfuric acid solution to graphite powder of 5:1 and a sulfuric acid content of 98%. After stirring in an ice-water bath (temperature of 0℃) for 2 hours, potassium permanganate was slowly added at a mass ratio of 1:1 to graphite powder, and stirring in an ice-water bath was continued for 2 hours. Potassium permanganate was added at a mass ratio of 1:1 to graphite powder, and distilled water was gradually added at room temperature (23℃) at a mass ratio of 30:1 to graphite powder. The mixture was stirred at 95℃ for 3 hours. After cooling to room temperature, hydrogen peroxide (with a mass content of 30% H2O2) was added at a mass ratio of 0.75:1 to graphite powder, and the mixture was stirred at room temperature for 2 hours. After centrifugation, the mixture was washed with hydrochloric acid solution and distilled water, and then freeze-dried to obtain graphene oxide powder (denoted as GO).

[0055] (2) Preparation of sulfonated graphene oxide: The obtained GO was added to water and ultrasonically dispersed. The mass ratio of GO to water was 1:20. Then azobenzenesulfonic acid was added. The mass ratio of GO to azobenzenesulfonic acid was 1:3. The reaction was stirred in an ice-water bath for 3 h. After centrifugation, sulfonated graphene oxide (denoted as SGO) was obtained.

[0056] (3) Preparation of antibacterial carrier: SGO was weighed and added to methanol. After ultrasonic dispersion for 4 h, Zn(NO3)2·6H2O was added and stirred at 300 r / min for 1 h. 2-Methylimidazole was added and the mixture was stirred for 3 h to promote the reaction. The mass ratio of SGO to methanol volume was 3.5 g: 10 mL, and the mass ratio of SGO, Zn(NO3)2·6H2O and 2-methylimidazole was 0.4:1:2. Subsequently, the mixture was washed with methanol and centrifuged three times to remove impurities. It was dried at 70 °C for 12 h and ground to obtain an antibacterial carrier containing SGO and a metal imidazolium salt skeleton. The obtained antibacterial carrier was weighed. The mass of the antibacterial carrier minus the mass of added SGO was the mass of the metal imidazolium salt skeleton. The mass ratio of SGO to metal imidazolium salt skeleton in the antibacterial carrier was 1:4.

[0057] (4) Preparation of antibacterial agent: The antibacterial carrier was added to distilled water and ultrasonically dispersed for 2 hours. Then silver nitrate was added and stirred at 500 r / min at room temperature for 24 hours. After washing, filtering and drying, the antibacterial agent was obtained. The mass ratio of antibacterial carrier to distilled water was 1:10, and the mass of silver ions in the antibacterial agent accounted for 2% of the mass of the antibacterial carrier.

[0058] Antibacterial agent 2: self-made. Its preparation method differs from that of antibacterial agent 1 in that, in the preparation method of antibacterial agent 2, the amount of silver nitrate added is adjusted so that the mass of silver ions in the antibacterial agent accounts for 4% of the mass of the antibacterial carrier.

[0059] Antibacterial agent 3: self-made. Its preparation method differs from that of antibacterial agent 1 in that, in the preparation method of antibacterial agent 3, the amount of silver nitrate added is adjusted so that the mass percentage of silver ions in the antibacterial agent accounts for 0.5% of the mass of the antibacterial carrier.

[0060] Antibacterial agent 4: self-made. Its preparation method differs from that of antibacterial agent 1 in that, in the preparation method of antibacterial agent 4, the amount of silver nitrate added is adjusted so that the mass percentage of silver ions in the antibacterial agent accounts for 8% of the mass of the antibacterial carrier.

[0061] Antibacterial agent 5: self-made, its preparation method is different from that of antibacterial agent 1. In the preparation method of antibacterial agent 5, the mass ratio of SGO, Zn(NO3)2·6H2O and 2-methylimidazole is 0.3:1:2, and the mass ratio of SGO to metal imidazole acid skeleton in the antibacterial carrier is 1:6.

[0062] Antibacterial agent 6: self-made, its preparation method differs from that of antibacterial agent 1 in that, in the preparation method of antibacterial agent 6, the mass ratio of SGO, Zn(NO3)2·6H2O and 2-methylimidazole is 0.6:1:2, and the mass ratio of SGO to the metal imidazolium salt skeleton in the antibacterial carrier is 1:2;

[0063] Antibacterial agent 7: self-made, its preparation method differs from that of antibacterial agent 1 in that, in the preparation method of antibacterial agent 7, the mass ratio of SGO, Zn(NO3)2·6H2O and 2-methylimidazole is 0.2:1:2, and the mass ratio of SGO to the metal imidazolium salt skeleton in the antibacterial carrier is 1:8;

[0064] Antibacterial Agent 8: Self-made. Its preparation method differs from that of Antibacterial Agent 1 in that: Zn(NO3)2·6H2O is added to methanol and stirred at 300 r / min for 1 h; 2-methylimidazole is added and mixing and stirring are continued for 3 h to promote the reaction; subsequently, the mixture is washed with methanol and centrifuged three times to remove impurities, and then dried at 70℃ for 12 hours. After grinding, a metallic imidazolium salt skeleton was obtained, wherein the mass ratio of Zn(NO3)2·6H2O to 2-methylimidazole was 0.7:1:2, and the mass ratio of Zn(NO3)2·6H2O to methanol was 5 g:10 mL. The metallic imidazolium salt skeleton was added to distilled water and ultrasonically dispersed for 2 h. Then, silver nitrate was added, and the mixture was stirred at 500 r / min at room temperature for 24 h. After washing, filtering, and drying, an antibacterial agent was obtained. The mass ratio of the metallic imidazolium salt skeleton to distilled water was 1:10, and the mass percentage of silver ions in the antibacterial agent was 2% of the mass of the metallic imidazolium salt skeleton.

[0065] Antibacterial agent 9: self-made, its preparation method is different from that of antibacterial agent 1. The preparation method of antibacterial agent 9 is: to prepare an antibacterial carrier according to steps (1) to (3) in the preparation method of antibacterial agent 1, and use the prepared antibacterial carrier as an antibacterial agent;

[0066] Antibacterial agent 10: self-made, its preparation method is different from that of antibacterial agent 1. The preparation method of antibacterial agent 10 is as follows: SGO is prepared according to steps (1) and (2) in the preparation method of antibacterial agent 1. SGO is added to distilled water and ultrasonically dispersed for 2 hours. Then silver nitrate is added and stirred at 500 r / min at room temperature for 24 hours. After washing, filtering and drying, the antibacterial agent is obtained. The mass ratio of SGO to distilled water is 1:10. The mass of silver ions in the antibacterial agent accounts for 2% of the mass of SGO.

[0067] Antibacterial agent 11: self-made, its preparation method is different from that of antibacterial agent 1. The preparation method of antibacterial agent 11 is: SGO is prepared according to steps (1) and (2) in the preparation method of antibacterial agent 1, and the prepared SGO is used as antibacterial agent.

[0068] Examples 1-11

[0069] Embodiments 1-11 of the present invention provide an antibacterial polyolefin composite pipe, wherein the antibacterial polyolefin composite pipe comprises an inner layer and an outer layer; the preparation method of the antibacterial polyolefin composite pipe is as follows:

[0070] S1. According to the component content (parts by mass) in Table 1, add each component of the inner layer to the high-speed mixer and mix evenly at a speed of 2000 r / min. Then add it to the twin-screw extruder and extrude and granulate at 170~190℃. The screw speed of the twin-screw extruder is 100 r / min. After drying, the inner layer material is obtained.

[0071] According to the component content (parts by mass) in Table 2, the components of the outer layer are added to a high-speed mixer and mixed evenly at a speed of 2000 r / min. Then, the mixture is added to a twin-screw extruder and extruded and granulated at 170~190℃. The screw speed of the twin-screw extruder is 100 r / min. After drying, the outer layer material is obtained.

[0072] S2. The inner and outer layer materials are extruded through a single-screw extruder (the temperature of the single-screw extruder is 190~210℃, and the screw speed is 80r / min) through a double-layer co-extrusion die. After vacuum shaping, cooling, traction, and cutting, polyolefin composite pipes are obtained. The specifications of the polyolefin composite pipes are: pipe diameter 20mm, wall thickness 3.4mm, the thickness of the inner layer accounts for 30% of the wall thickness, and the thickness of the outer layer accounts for 70% of the wall thickness.

[0073] Table 1 shows the components of the inner layer in each embodiment and their mass parts (the unit of mass parts is: parts).

[0074]

[0075] Table 2 shows the components of the outer layer and their mass parts in each embodiment (mass parts are in parts).

[0076]

[0077] Comparative Examples 1-7

[0078] The difference between Comparative Examples 1-7 and Example 3 is that the components of the inner layer and the mass fraction of each component in Comparative Examples 1-7 are shown in Table 3.

[0079] Table 3 shows the components of the inner layer and their mass fractions in each comparative example (mass fractions are in parts).

[0080]

[0081] Performance testing

[0082] Using the pipes provided in the above embodiments and comparative examples as samples, corresponding performance tests were conducted. The test results are shown in Table 4. The specific test methods are as follows:

[0083] (1) Mechanical strength (MPa): Tested according to the method specified in standard GB / T 8804.3-2004;

[0084] (2) Hydrostatic pressure of pipe (MPa): The hydrostatic test shall be carried out according to the method specified in standard GB / T 18742.2-2017. The hydrostatic test shall be carried out under standard pressure. After the test is passed, the pressure shall be increased by 5% to carry out the hydrostatic test until the pipe breaks. The time of each hydrostatic test shall be 1 hour and the temperature shall be 22℃. The hydrostatic pressure at which the pipe breaks shall be recorded.

[0085] (3) Initial antibacterial properties and antibacterial durability: Initial antibacterial properties and antibacterial durability were tested according to the method specified in standard JC / T 939-2004;

[0086] (4) Hygiene performance (silver precipitation): Tested according to the method specified in standard GB / T 17219-1998;

[0087] (5) Antibacterial rate after hydrostatic test at 95℃ / 165 h: The hydrostatic test was conducted in accordance with standard GB / T 18742.2-2017, with a test temperature of 95℃ and a test time of 165h; after the hydrostatic test, the antibacterial rate was tested in accordance with standard JC / T 939-2004.

[0088] Table 4

[0089]

[0090] In various embodiments of the present invention, an antibacterial agent is introduced into the inner layer. This antibacterial agent uses a compound of sulfonated graphene oxide and metal imidazolate skeleton as an antibacterial carrier, and the antibacterial carrier is compounded with silver ions. Under the synergistic effect of sulfonated graphene oxide, metal imidazolate skeleton (ZIFs) and silver ions, the polyolefin composite pipe has good mechanical properties, hygienic properties, initial antibacterial properties and antibacterial durability.

[0091] Compared to Example 3, the antibacterial agent in Comparative Example 1 did not contain sulfonated graphene oxide, resulting in a sharp drop in the mechanical properties and antibacterial durability of the polyolefin composite pipe.

[0092] Compared with Example 3, the antibacterial agent in Comparative Example 2 did not contain silver ions, and the initial antibacterial properties and antibacterial durability of the polyolefin composite pipe were significantly reduced.

[0093] Compared with Example 3, the antibacterial agent in Comparative Example 3 did not contain a metal imidazolate backbone, resulting in a significant increase in silver deposition in the polyolefin composite pipe and a significant decrease in initial antibacterial properties and antibacterial durability.

[0094] Compared with Example 3, the antibacterial agent in Comparative Example 4 does not contain a metal imidazolate skeleton and silver ions. Although the mechanical properties of the polyolefin composite pipe are slightly improved, the initial antibacterial properties and antibacterial durability are significantly reduced.

[0095] Compared with Example 3, the amount of antibacterial agent added in Comparative Example 5 was too small, and the initial antibacterial properties and antibacterial durability of the polyolefin composite pipe were significantly reduced; no antibacterial agent was added in Comparative Example 6, and the antibacterial properties of the polyolefin composite pipe were extremely low; the amount of antibacterial agent added in Comparative Example 7 was too large. Although the initial antibacterial properties and antibacterial durability were guaranteed, the mechanical properties dropped sharply, the hygienic properties also decreased significantly, and the amount of silver ions precipitated exceeded 0.03 g / L.

[0096] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of the present invention and not to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An antibacterial polyolefin composite pipe, characterized by, The inner layer comprises the following components by mass fraction: random copolymerized polypropylene 88-95 parts, antibacterial agent 3-6 parts, compatibilizer 3-6 parts, antioxidant 0.1-1 part; the antibacterial agent comprises silver ions and an antibacterial carrier, the percentage of the mass of the silver ions to the mass of the antibacterial carrier is not less than 0.5%, and the antibacterial carrier comprises sulfonated graphene oxide and a metal imidazole acid salt skeleton, the mass ratio of the sulfonated graphene oxide to the metal imidazole acid salt skeleton is 1:(2-8); The antibacterial carrier is prepared by the following method: The sulfonated graphene oxide, methanol and soluble zinc salt are mixed, then 2-methyl imidazole is added for mixing reaction, and the antibacterial carrier is obtained through filtration, washing, drying and grinding; The material of the outer layer comprises random copolymerized polypropylene.

2. The antimicrobial polyolefin composite pipe according to claim 1, wherein, The percentage of the mass of the silver ions to the mass of the antibacterial carrier is 0.5-8%.

3. The antimicrobial polyolefin composite pipe of claim 1, wherein, The mass ratio of the sulfonated graphene oxide to the metal imidazole acid salt skeleton is 1:(4-6).

4. The antimicrobial polyolefin composite pipe of claim 1, wherein, The mass ratio of the sulfonated graphene oxide, soluble zinc salt and 2-methyl imidazole is sulfonated graphene oxide:soluble zinc salt:2-methyl imidazole=(0.2-0.6):1:2; And / or, the mixing reaction conditions are: stirring speed 100-500 r / min, reaction time 2-4 h; And / or, the ratio between the mass of the sulfonated graphene oxide and the volume of methanol is (3-4) g:10 mL; And / or, the step of mixing the sulfonated graphene oxide, methanol and soluble zinc salt is: the sulfonated graphene oxide and methanol are mixed, then ultrasonic dispersion is performed for 3-5 h, and then the soluble zinc salt is added for stirring and dispersion for 0.5-2 h.

5. The antimicrobial polyolefin composite pipe of claim 1, wherein, The sulfonated graphene oxide is prepared by the following method: The graphene oxide, water and azobenzenesulfonic acid are mixed, then reaction is performed at 0-5 ℃ for 2-4 h, and the sulfonated graphene oxide is obtained through centrifugal separation; the mass ratio of the graphene oxide to the azobenzenesulfonic acid is 1:(2-4).

6. The antimicrobial polyolefin composite pipe of claim 1, wherein, The outer layer comprises the following components by mass fraction: random copolymerized polypropylene 98-99 parts, compatibilizer 1-2 parts, antioxidant 0.1-1 part.

7. The antimicrobial polyolefin composite pipe of claim 1, wherein, The antioxidant comprises at least one of hindered phenolic antioxidant and phosphite antioxidant, the hindered phenolic antioxidant comprises at least one of tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester, 2,6-di-tert-butyl-p-cresol and bis(3,5-di-tert-butyl-4-hydroxy-phenylpropionyl)hydrazine, and the phosphite antioxidant comprises at least one of triphenyl phosphite and tributyl sulfite; And / or, the compatibilizer comprises polypropylene grafted maleic anhydride.

8. A method for producing the antibacterial polyolefin composite pipe according to any one of claims 1 to 7, characterized by, The steps comprise: S1, the components of the inner layer are mixed and then extrusion granulation is performed to obtain an inner layer material; the components of the outer layer are mixed and then extrusion granulation is performed to obtain an outer layer material; S2, the inner layer material and the outer layer material are subjected to co-extrusion, vacuum sizing, cooling, traction and slitting to obtain an antibacterial polyolefin composite pipe.

9. The method for preparing the antibacterial polyolefin composite pipe as described in claim 8, characterized in that, In step S1, the temperature of the extrusion granulation is 170-190 DEG C, and the screw rotation speed of the extrusion granulation is 100-120 r / min; and / or, in step S2, the temperature of the co-extrusion is 190-210 DEG C, and the screw rotation speed of the co-extrusion is 30-100 r / min.

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