Antibacterial polyolefin composite pipe and preparation method thereof

Abstract

The invention 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, wherein the inner layer comprises the following components in parts by mass: 88-95 parts of polypropylene random copolymer, 3-6 parts of an antibacterial agent, 3-6 parts of a compatilizer and 0.1-1 part of an antioxidant; the antibacterial agent comprises silver ions and an antibacterial carrier, and the antibacterial carrier comprises sulfonated graphene oxide and a metal type imidazolate skeleton. The antibacterial agent is introduced into the inner layer, the antibacterial agent is compounded by an antibacterial carrier and silver ions, precipitation of silver can be effectively slowed down, the initial antibacterial effect of the polyolefin composite pipe is guaranteed, meanwhile, the antibacterial durability of the polyolefin composite pipe is improved, breeding of microorganisms such as bacteria can be effectively inhibited under the actual working condition of tap water, and the service life of the polyolefin composite pipe is prolonged. Therefore, a pipeline system of the polyolefin composite pipe is suitable for conveying drinking water for a long time.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer pipes, and in particular relates to an antibacterial polyolefin composite pipe and a preparation method thereof. Background Art

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

[0003] PP-R pipe, short for random copolymer polypropylene pipe, is a random copolymer formed by the copolymerization of propylene and another olefin monomer. The irregular distribution of the comonomers within the polypropylene chain alters the molecular structure of polypropylene, giving PP-R pipes superior physical and chemical properties. PP-R pipes are lightweight, corrosion-resistant, have smooth, scale-free inner walls, are easy to construct and maintain, and have a long service life. They are currently widely used in building water supply and drainage, urban and rural drainage, municipal administration, and other fields, and have quickly gained market recognition. However, in actual water supply applications, with long-term use, it has been discovered that bacteria and other microorganisms adhere to and breed on the inner surface of PP-R pipes, forming a mucous membrane-like substance. In severe cases, large amounts of scale impurities can form, making them difficult to flush clean with the natural pressure of water, severely affecting water quality and ultimately rendering them useless.

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

[0005] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide an antibacterial polyolefin composite pipe and a preparation method thereof. The polyolefin composite pipe has good antibacterial effect. The pipeline system of the pipe can effectively inhibit the growth of microorganisms such as bacteria under the actual working conditions of tap water, reduce scale impurities, and ensure the hygiene and cleanliness of the inside of the pipe.

[0006] To achieve the above object, the technical solution adopted by the present invention is: In a first aspect, the present invention provides a chlorinated polyolefin composite pipe, comprising an inner layer and an outer layer, wherein the inner layer comprises the following components in parts by weight: 88 to 95 parts of random copolymer polypropylene, 3 to 6 parts of an antibacterial agent, 3 to 6 parts of a compatibilizer, and 0.1 to 1 part of an antioxidant; the antibacterial agent comprises silver ions and an antibacterial carrier, wherein the mass of the silver ions accounts for no less than 0.5% of the mass of the antibacterial carrier; the antibacterial carrier comprises sulfonated graphene oxide and a metallic imidazolate skeleton, and the mass ratio of the sulfonated graphene oxide to the metallic imidazolate skeleton is 1:(2 to 8); The material of the outer layer includes random copolymer polypropylene.

[0007] The antibacterial polyolefin composite pipe provided by the present invention introduces an antibacterial agent into the inner layer. The antibacterial agent adopts a compound of sulfonated graphene oxide and a metallic imidazolate skeleton as an antibacterial carrier. This antibacterial carrier is compounded with silver ions, which can effectively slow down the precipitation of silver. While ensuring the initial antibacterial effect of the polyolefin composite pipe, the antibacterial durability of the polyolefin composite pipe is improved. Under the actual working conditions of tap water, it can effectively inhibit the growth of microorganisms such as bacteria, reduce scale impurities, and ensure the sanitation and cleanliness of the inside of the pipe, so that the pipeline system of the polyolefin composite pipe is suitable for long-term transportation of drinking water.

[0008] Metallic imidazolate frameworks (ZIFs) have a rich porous structure, which can provide more adsorption sites and adsorption channels, and fix silver ions in their structure through ion exchange; sulfonated graphene oxide has a large specific surface area and excellent chemical stability, which can provide good attachment sites for metallic imidazolate frameworks (ZIFs) and can also interact with the metallic imidazolate frameworks through hydrogen bonds and coordination bonds; the synergistic effect of silver ions, sulfonated graphene oxide and metallic imidazolate frameworks enhances the initial antibacterial properties of polyolefin composite pipes, and by enhancing the sustained release effect, controls the precipitation rate of silver ions, thereby ensuring the hygienic properties of polyolefin composite pipes while improving the antibacterial durability of the pipes.

[0009] Sulfonated graphene oxide contains a large number of sulfonic acid functional groups, which can effectively improve the dispersibility and thermal stability of the antibacterial agent, thereby improving the processing stability of the pipe; the compounding of sulfonated graphene oxide and metallic imidazolate skeleton gives the antibacterial carrier a unique layered structure and extremely low interlayer shear strength. The introduction of this antibacterial carrier can greatly reduce the friction coefficient of the inner layer system, improve the melt fluidity and processing formability of the inner layer system, reduce the shear peak during the extrusion process, improve the quality of the pipe, and thus ensure the mechanical properties of the pipe.

[0010] Exemplarily, in the inner layer, the mass parts of the random copolymer polypropylene can be 88 parts, 89 parts, 90 parts, 91 parts, 92 parts, 93 parts, 94 parts, 95 parts or a range consisting of any two groups of values ​​therein, the mass parts of the antibacterial agent can be 3 parts, 4 parts, 5 parts, 6 parts or a range consisting of any two groups of values ​​therein, the mass parts of the compatibilizer can be 3 parts, 4 parts, 5 parts, 6 parts or a range consisting of any two groups of values ​​therein, and the mass parts of the antioxidant can be 0.1 parts, 0.3 parts, 0.5 parts, 0.8 parts, 1 part or a range consisting of any two groups of values ​​therein.

[0011] Exemplarily, the mass ratio of the sulfonated graphene oxide to the metallic imidazolate skeleton can be 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, or a range consisting of any two of these mass ratios.

[0012] Preferably, the outer layer comprises the following components in parts by mass: 98-99 parts of random copolymer polypropylene, 1-2 parts of a compatibilizer, and 0.1-1 part of an antioxidant.

[0013] 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 part of antioxidant.

[0014] Preferably, the mass percentage of the silver ions to the mass percentage of the antimicrobial carrier is 0.5-8%. Exemplarily, the mass percentage of the silver ions to the mass percentage of the antimicrobial carrier can be 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, or a range consisting of any two of these values.

[0015] Further preferably, the mass of the silver ions accounts for 2-8% of the mass of the antibacterial carrier.

[0016] Preferably, the mass ratio of the sulfonated graphene oxide to the metallic imidazolate skeleton is 1:(4-6). When the mass ratio of the sulfonated graphene oxide to the metallic imidazolate skeleton is within the above preferred range, the overall performance of the polyolefin composite pipe is better.

[0017] Preferably, the antibacterial carrier is prepared by the following method: After mixing sulfonated graphene oxide, methanol and soluble zinc salt, 2-methylimidazole is added to carry out mixing reaction, and the mixture is filtered, washed, dried and ground to obtain the antibacterial carrier.

[0018] During the above-mentioned mixing reaction process, the nitrogen atom (N) in the 2-methylimidazole molecule acts as a coordination site, forms an imidazole group through deprotonation, and forms a coordination bond with the zinc ion of the soluble zinc salt, thereby generating a metal imidazolate skeleton.

[0019] Further 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.

[0020] Illustratively, the mass ratio of the sulfonated graphene oxide, the 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 a range consisting of any two of these mass ratios.

[0021] Further preferably, the soluble zinc salt includes at least one of zinc nitrate and zinc chloride.

[0022] More preferably, the mixing reaction conditions are: stirring speed 100-500 r / min, reaction time 2-4 h.

[0023] Further preferably, the ratio between the mass of the sulfonated graphene oxide and the volume of methanol is (3-4) g:10 mL.

[0024] Further preferably, the step of mixing the sulfonated graphene oxide, methanol and soluble zinc salt is: mixing the sulfonated graphene oxide and methanol and then ultrasonically dispersing them for 3 to 5 hours, and then adding the soluble zinc salt and stirring and dispersing them for 0.5 to 2 hours.

[0025] Preferably, the sulfonated graphene oxide is prepared by the following method: Graphene oxide, water and azobenzenesulfonic acid are mixed, reacted at 0-5° C. for 2-4 hours, and centrifuged to obtain the sulfonated graphene oxide; the mass ratio of the graphene oxide to the azobenzenesulfonic acid is 1:(2-4).

[0026] Further preferably, the method for preparing graphene oxide comprises the following steps: mixing a sulfuric acid solution and graphite powder, stirring and mixing at 0-5°C for 1-3 hours, then adding potassium permanganate, heating to 20-30°C, adding water, then heating to 90-100°C and stirring for 2-4 hours, cooling to 20-30°C, adding a hydrogen peroxide solution and mixing, filtering, washing, and drying to obtain graphene oxide.

[0027] 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 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 mass percentage of hydrogen peroxide in the hydrogen peroxide is 25-30%, and the mass concentration of sulfuric acid in the sulfuric acid solution is 95-98%.

[0028] Preferably, the preparation method of the antibacterial agent comprises the following steps: compounding sulfonated graphene oxide and a metallic imidazolate skeleton, mixing water and silver nitrate, and ultrasonically dispersing the mixture, followed by filtering, washing, and drying to obtain the antibacterial agent.

[0029] Preferably, the density of the random copolymer polypropylene is 0.895~0.915g / cm 3 The melt flow rate of the random copolymer polypropylene at 190° C. and a load of 2.16 kg is 0.2 to 0.5 g / 10 min.

[0030] Preferably, the antioxidant includes at least one of a hindered phenol antioxidant and a phosphite antioxidant, the hindered phenol antioxidant includes at least one of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol ester, 2,6-di-tert-butyl-p-cresol, and bis(3,5-di-tert-butyl-4-hydroxy-phenylpropionyl)hydrazine, and the phosphite antioxidant includes at least one of triphenyl phosphite and tributyl sulfite.

[0031] Preferably, the compatibilizer comprises polypropylene grafted maleic anhydride, and the density of the polypropylene grafted maleic anhydride is 0.9-1.0 g / cm 3 , the melt flow rate is 5~10g / 10min, and the grafting rate of maleic anhydride is 1~1.5%.

[0032] Preferably, the thickness of the inner layer accounts for no less than 30% of the total thickness of the antibacterial polyolefin composite pipe.

[0033] Further preferably, the thickness of the inner layer accounts for 30-80% of the total thickness of the antibacterial polyolefin composite pipe.

[0034] In a second aspect, the present invention provides a method for preparing the antibacterial polyolefin composite pipe as described in the first aspect, comprising the following steps: S1. Mix the components of the inner layer and extrude and granulate them to obtain the inner layer material; mix the components of the outer layer and extrude and granulate them to obtain the outer layer material; S2. Co-extrude the inner layer material and the outer layer material, perform vacuum sizing, cool, pull, and cut to obtain an antibacterial polyolefin composite pipe.

[0035] Preferably, in step S1, the temperature of the extrusion granulation is 170-190° C., and the screw speed of the extrusion granulation is 100-120 r / min.

[0036] Preferably, in step S2, the co-extrusion temperature is 190-210° C., and the co-extrusion screw speed is 30-100 r / min.

[0037] Compared with the prior art, the present invention has the following beneficial effects: The antibacterial polyolefin composite pipe provided by the present invention introduces an antibacterial agent into the inner layer. The antibacterial agent adopts a compound of sulfonated graphene oxide and a metallic imidazolate skeleton as an antibacterial carrier. This antibacterial carrier is compounded with silver ions, which can effectively slow down the precipitation of silver. While ensuring the initial antibacterial effect of the polyolefin composite pipe, the antibacterial durability of the polyolefin composite pipe is improved. Under the actual working conditions of tap water, it can effectively inhibit the growth of microorganisms such as bacteria, reduce scale impurities, and ensure the sanitation and cleanliness of the inside of the pipe, so that the pipeline system of the polyolefin composite pipe is suitable for long-term transportation of drinking water. DETAILED DESCRIPTION

[0038] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0039] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0040] Unless otherwise specified, the components used in the parallel experiments of the Examples of the present invention and the Comparative Examples were derived from the same sources.

[0041] The raw materials used in the present invention are as follows: Random copolymer polypropylene: brand 4220, manufactured by Beijing Yanshan Branch of Sinopec, density 0.895 g / cm 3 , according to GB / T 3682-2000, the melt flow rate at 230°C and 2.16kg load is 0.23g / 10min; Compatibilizer: Polypropylene grafted maleic anhydride, brand 18722 SK, manufacturer: Comprehensive Chemical, density 0.900g / cm 3 According to GB / T 3682-2000, the melt flow rate at 230°C and 2.16 kg load was 7.0 g / 10 min, and the grafting rate of maleic anhydride was 1.3%; Graphite powder: manufacturer is Changzhou Sixth Element Co., Ltd. Antioxidant: a mixture of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and 2,6-di-tert-butyl-p-cresol in a mass ratio of 1:1; Antibacterial agent 1: Homemade, its preparation method is: (1) Preparation of graphene oxide: add sulfuric acid solution to a beaker containing graphite powder, the mass ratio of sulfuric acid solution to graphite powder is 5:1, and the mass percentage of sulfuric acid in the sulfuric acid solution is 98%. After stirring in an ice-water bath (temperature is 0℃) for 2h, slowly add potassium permanganate in a mass ratio of potassium permanganate to graphite powder of 1:1, and continue stirring in an ice-water bath for 2h; add potassium permanganate in a mass ratio of potassium permanganate to graphite powder of 1:1, and gradually add distilled water in a mass ratio of distilled water to graphite powder of 30:1 at room temperature (23℃), and stir at 95℃ for 3h; after cooling to room temperature, add hydrogen peroxide (wherein the mass percentage of H2O2 is 30%) in a mass ratio of hydrogen peroxide to graphite powder of 0.75:1, and stir at room temperature for 2h; centrifuge the obtained mixture, wash it with hydrochloric acid solution and distilled water in sequence, and freeze-dry to obtain graphene oxide powder (denoted as GO); (2) Preparation of sulfonated graphene oxide: The obtained GO was added to water for ultrasonic dispersion, with the mass ratio of GO to water being 1:20. Then azobenzenesulfonic acid was added, with the mass ratio of GO to azobenzenesulfonic acid being 1:3. The mixture was stirred in an ice-water bath for 3 h, and sulfonated graphene oxide (denoted as SGO) was obtained after centrifugation. (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 continued to mix and stir for 3 h to promote the reaction. The ratio of the mass of SGO to the volume of methanol 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 product was washed and centrifuged three times with methanol to remove impurities, dried at 70 °C for 12 h, and ground to obtain an antibacterial carrier containing SGO and a metal imidazolate skeleton. The obtained antibacterial carrier was weighed, and the mass of the antibacterial carrier minus the added mass of SGO was the mass of the metal imidazolate skeleton. The mass ratio of SGO to the metal imidazolate skeleton in the antibacterial carrier was 1:4. (4) Preparation of antibacterial agent: add the antibacterial carrier to distilled water, ultrasonically disperse for 2 h, then add silver nitrate, stir at room temperature and 500 r / min for 24 h, wash, filter, and dry to obtain the antibacterial agent; the mass ratio of the antibacterial carrier to distilled water is 1:10, and the mass of silver ions in the antibacterial agent accounts for 2% of the mass of the antibacterial carrier; Antimicrobial agent 2: homemade. The difference between its preparation method and that of antimicrobial agent 1 is that, in the preparation method of antimicrobial agent 2, the amount of silver nitrate added is adjusted so that the mass percentage of silver ions in the antimicrobial agent to the mass percentage of the antimicrobial carrier is 4%; Antimicrobial agent 3: homemade. Its preparation method differs from that of antimicrobial agent 1 in that, in the preparation method of antimicrobial agent 3, the amount of silver nitrate added is adjusted so that the mass percentage of silver ions in the antimicrobial agent to the mass percentage of the antimicrobial carrier is 0.5%; Antimicrobial agent 4: homemade. Its preparation method differs from that of antimicrobial agent 1 in that, in the preparation method of antimicrobial agent 4, the amount of silver nitrate added is adjusted so that the mass percentage of silver ions in the antimicrobial agent to the mass percentage of the antimicrobial carrier is 8%; Antimicrobial agent 5: homemade. Its preparation method is different from that of antimicrobial agent 1 in that, in the preparation method of antimicrobial 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 the metal imidazolate skeleton in the antimicrobial carrier is 1:6; Antibacterial agent 6: self-made, the difference between the preparation method of the antibacterial agent 6 and the antibacterial agent 1 is that the mass ratio of SGO, Zn(NO3)2·6H2O and 2-methylimidazole in the preparation method of the antibacterial agent 6 is 0.6:1:2, and the mass ratio of SGO and the metal imidazole acid salt skeleton in the antibacterial carrier is 1:2; Antibacterial agent 7: self-made, the difference between the preparation method of the antibacterial agent 7 and the antibacterial agent 1 is that the mass ratio of SGO, Zn(NO3)2·6H2O and 2-methylimidazole in the preparation method of the antibacterial agent 7 is 0.2:1:2, and the mass ratio of SGO and the metal imidazole acid salt skeleton in the antibacterial carrier is 1:8; Antibacterial agent 8: self-made, the difference between the preparation method of the antibacterial agent 8 and the antibacterial agent 1 is that the preparation method of the antibacterial agent 8 is that Zn(NO3)2·6H2O is added into methanol, stirred at a speed of 300 r / min for 1 h, 2-methylimidazole is added and continues to be mixed and stirred for 3 h to promote the reaction; then, the mixture is washed and centrifuged three times with methanol to remove impurities, dried at 70℃ for 12 h, and grinded to obtain the metal imidazole acid salt skeleton, wherein the mass ratio of Zn(NO3)2·6H2O and 2-methylimidazole is 0.7:1:2, and the mass of Zn(NO3)2·6H2O to the volume of methanol is 5 g:10 mL; the metal imidazole acid salt skeleton is added into distilled water, ultrasonically dispersed for 2 h, and then silver nitrate is added, stirred at a speed of 500 r / min at room temperature for 24 h, and then washed, filtered and dried to obtain the antibacterial agent; the mass ratio of the metal imidazole acid salt skeleton to distilled water is 1:10, and the mass percentage of silver ions in the antibacterial agent to the mass of the metal imidazole acid salt skeleton is 2%; Antibacterial agent 9: self-made, the difference between the preparation method of the antibacterial agent 9 and the antibacterial agent 1 is that the preparation method of the antibacterial agent 9 is that the antibacterial carrier is prepared according to steps (1) to (3) in the preparation method of the antibacterial agent 1, and the prepared antibacterial carrier is used as the antibacterial agent; Antibacterial agent 10: self-made, the difference between the preparation method of the antibacterial agent 10 and the antibacterial agent 1 is that the preparation method of the antibacterial agent 10 is that SGO is prepared according to steps (1) and (2) in the preparation method of the antibacterial agent 1, the SGO is added into distilled water, ultrasonically dispersed for 2 h, and then silver nitrate is added, stirred at a speed of 500 r / min at room temperature for 24 h, and then washed, filtered and dried to obtain the antibacterial agent, and the mass ratio of SGO to distilled water is 1:10, and the mass percentage of silver ions in the antibacterial agent to the mass of SGO is 2%; Antibacterial agent 11: self-made, the difference between the preparation method of the antibacterial agent 11 and the antibacterial agent 1 is that the preparation method of the antibacterial agent 11 is that SGO is prepared according to steps (1) and (2) in the preparation method of the antibacterial agent 1, and the prepared SGO is used as the antibacterial agent.

[0042] Examples 1~11 Embodiments 1 to 11 of the present invention respectively provide an antibacterial polyolefin composite pipe, wherein the antibacterial polyolefin composite pipe comprises an inner layer and an outer layer; and the preparation method of the antibacterial polyolefin composite pipe is as follows: S1. According to the component contents (parts by mass) in Table 1, the components of the inner layer were added to a high-speed mixer and mixed uniformly at a speed of 2000 r / min. The mixture was then added to a twin-screw extruder and extruded into granules at 170-190°C. The screw speed of the twin-screw extruder was 100 r / min. The inner layer material was obtained by drying. According to the component contents (parts by mass) in Table 2, the components of the outer layer were added to a high-speed mixer and mixed uniformly at a speed of 2000 r / min. The mixture was then added to a twin-screw extruder and extruded into granules at 170-190°C. The screw speed of the twin-screw extruder was 100 r / min. The outer layer material was obtained after drying. S2. The inner layer material and the outer layer material are respectively passed through a single-screw extruder (the temperature of the single-screw extruder is 190-210°C and the screw speed is 80 r / min), extruded through a double-layer co-extrusion die, vacuum-formed, cooled, pulled, and cut to obtain a polyolefin composite pipe. The specifications of the polyolefin composite pipe are: pipe diameter 20 mm, wall thickness 3.4 mm, 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.

[0043] Table 1 Components of the inner layer in each embodiment and their mass parts (the unit of mass parts is: part) Table 2 Components of the outer layer in each embodiment and their mass parts (unit of mass parts: parts) Comparative Examples 1 to 7 The difference between Comparative Examples 1 to 7 and Example 3 is that the components of the inner layer in Comparative Examples 1 to 7 and the weight parts of the components are shown in Table 3.

[0044] Table 3 Components of the inner layer in each comparative example and their mass parts (the unit of mass parts is: parts) Performance Testing The pipes provided in the above embodiments and comparative examples were used as samples to conduct corresponding performance tests. The test results are shown in Table 4. The specific test methods are as follows: (1) Mechanical strength (MPa): tested according to the method specified in GB / T 8804.3-2004; (2) Hydrostatic pressure of pipe (MPa): The hydrostatic pressure test is carried out according to the method specified in GB / T 18742.2-2017. The hydrostatic pressure test is carried out at the standard pressure. After the test is passed, the hydrostatic pressure test is carried out at a 5% amplitude until the pipe ruptures. The duration of each hydrostatic pressure test is 1 hour, the temperature is 22°C, and the hydrostatic pressure at which the pipe ruptures is recorded. (3) Initial antibacterial properties and antibacterial durability: The initial antibacterial properties and antibacterial durability tests were carried out according to the methods specified in the standard JC / T 939-2004; (4) Hygienic performance (silver precipitation): Tested in accordance with the method specified in GB / T 17219-1998; (5) Antibacterial rate after 95℃ / 165h hydrostatic test: The hydrostatic test was carried out in accordance with the 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 test was carried out in accordance with the provisions of the standard JC / T 939-2004.

[0045] Table 4 Each embodiment of the present invention introduces an antibacterial agent into the inner layer. The antibacterial agent uses a compound of sulfonated graphene oxide and a metallic imidazolate skeleton as an antibacterial carrier, and the antibacterial carrier is compounded with silver ions. Under the synergistic effect of sulfonated graphene oxide, metallic imidazolate skeletons (ZIFs) and silver ions, the polyolefin composite pipe has good mechanical properties, hygienic properties, initial antibacterial properties and antibacterial durability.

[0046] Compared with Example 3, the antibacterial agent in Comparative Example 1 does not contain sulfonated graphene oxide, and the mechanical properties and antibacterial durability of the polyolefin composite pipe drop sharply.

[0047] Compared with Example 3, the antibacterial agent in Comparative Example 2 does not contain silver ions, and the initial antibacterial properties and antibacterial durability of the polyolefin composite pipe are significantly reduced.

[0048] Compared with Example 3, the antibacterial agent in Comparative Example 3 does not contain a metal imidazolate skeleton, the silver precipitation amount of the polyolefin composite pipe is significantly increased, and the initial antibacterial activity and antibacterial durability are significantly reduced.

[0049] Compared with Example 3, the antibacterial agent in Comparative Example 4 does not contain a metallic imidazolate skeleton and silver ions. Although the mechanical properties of the polyolefin composite pipe are slightly improved, the initial antibacterial activity and antibacterial durability are significantly reduced.

[0050] Compared with Example 3, the amount of antibacterial agent added in Comparative Example 5 is too small, and the initial antibacterial properties and antibacterial durability of the polyolefin composite pipe are significantly reduced; in Comparative Example 6, no antibacterial agent is added, and the antibacterial properties of the polyolefin composite pipe are extremely low; in Comparative Example 7, the amount of antibacterial agent added is too much. Although the initial antibacterial properties and antibacterial durability are guaranteed, the mechanical properties drop sharply, the sanitary properties also drop significantly, and the amount of silver ion precipitation exceeds 0.03 g / L.

[0051] Finally, it should be noted that the above embodiments are intended to illustrate the technical solutions of the present invention rather than 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 the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An antibacterial polyolefin composite pipe, characterized in that: The invention comprises an inner layer and an outer layer, wherein the inner layer comprises the following components in parts by weight: 88 to 95 parts of random copolymer polypropylene, 3 to 6 parts of an antibacterial agent, 3 to 6 parts of a compatibilizer, and 0.1 to 1 part of an antioxidant; the antibacterial agent comprises silver ions and an antibacterial carrier, wherein the mass of the silver ions accounts for no less than 0.5% of the mass of the antibacterial carrier; the antibacterial carrier comprises sulfonated graphene oxide and a metallic imidazolate skeleton, and the mass ratio of the sulfonated graphene oxide to the metallic imidazolate skeleton is 1:(2 to 8); The material of the outer layer includes random copolymer polypropylene.

2. The antibacterial polyolefin composite pipe according to claim 1, characterized in that: The mass of the silver ions accounts for 0.5-8% of the mass of the antibacterial carrier.

3. The antibacterial polyolefin composite pipe according to claim 1, characterized in that: The mass ratio of the sulfonated graphene oxide to the metal imidazolate skeleton is 1:(4-6).

4. The antibacterial polyolefin composite pipe according to claim 1, characterized in that: The antibacterial carrier is prepared by the following method: After mixing sulfonated graphene oxide, methanol and soluble zinc salt, 2-methylimidazole is added to carry out mixing reaction, and the mixture is filtered, washed, dried and ground to obtain the antibacterial carrier.

5. The antimicrobial polyolefin composite pipe according to claim 4, characterized in that: 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; 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: mixing the sulfonated graphene oxide and methanol and then ultrasonically dispersing them for 3 to 5 hours, and then adding the soluble zinc salt and stirring and dispersing them for 0.5 to 2 hours.

6. The antimicrobial polyolefin composite pipe according to claim 1, characterized in that: The sulfonated graphene oxide is prepared by the following method: Graphene oxide, water and azobenzenesulfonic acid are mixed, reacted at 0-5° C. for 2-4 hours, and centrifuged to obtain the sulfonated graphene oxide; the mass ratio of the graphene oxide to the azobenzenesulfonic acid is 1:(2-4).

7. The antimicrobial polyolefin composite pipe according to claim 1, characterized in that: The outer layer comprises the following components in parts by weight: 98-99 parts of random copolymer polypropylene, 1-2 parts of a compatibilizer, and 0.1-1 part of an antioxidant.

8. The antimicrobial polyolefin composite pipe according to claim 1, wherein: The antioxidant includes at least one of a hindered phenol antioxidant and a phosphite antioxidant, the hindered phenol antioxidant includes at least one of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester, 2,6-di-tert-butyl-p-cresol, and bis(3,5-di-tert-butyl-4-hydroxy-phenylpropionyl)hydrazine, and the phosphite antioxidant includes at least one of triphenyl phosphite and tributyl sulfite; And / or, the compatibilizer comprises polypropylene grafted with maleic anhydride.

9. A method for preparing the antibacterial polyolefin composite pipe according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Mix the components of the inner layer and extrude and granulate them to obtain the inner layer material; mix the components of the outer layer and extrude and granulate them to obtain the outer layer material; S2. Co-extrude the inner layer material and the outer layer material, perform vacuum sizing, cool, pull, and cut to obtain an antibacterial polyolefin composite pipe.

10. The method for preparing the antibacterial polyolefin composite pipe according to claim 9, characterized in that: In step S1, the temperature of the extrusion granulation is 170-190° C., and the screw speed of the extrusion granulation is 100-120 r / min; And / or, in step S2, the co-extrusion temperature is 190-210° C., and the co-extrusion screw speed is 30-100 r / min.

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