Composite antibacterial agent and preparation method thereof, and PPR pipe

Abstract

The application relates to the technical field of materials, and discloses a composite antibacterial agent, a preparation method thereof and a PPR pipe. The preparation method of the composite antibacterial agent comprises the following steps: S1. mixing zinc acetate and glucose to perform a hydrothermal reaction, and calcining to obtain hollow ZnO microspheres; S2. mixing cerium nitrate, urea and the hollow ZnO microspheres to perform a reaction, and calcining to obtain ZnO@Ce composite material; and S3. mixing the ZnO@Ce composite material, silicon micro powder and a silane coupling agent to perform a reaction, so that the composite antibacterial agent is obtained. When the composite antibacterial agent is used for preparing the PPR pipe, the antibacterial property and the antibacterial durability of the PPR pipe can be improved.

Description

Technical Field

[0001] This invention relates to the field of materials technology, and more specifically, to a composite antibacterial agent and its preparation method, and PPR pipe. 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 transporting clean drinking water. PPR pipes are mainly made of random copolymer polypropylene material, and are widely used in building water supply and drainage, urban and rural drainage, and municipal fields due to their lightweight, corrosion resistance, and ease of construction and maintenance. However, because PPR pipes are not easily replaced after installation, after a period of use, a large number of bacteria and algae easily grow on the inner wall of the PPR pipe, and in severe cases, a large amount of scale and impurities will form. It is difficult to clean them by the natural pressure of water, which affects the performance of the PPR pipe, shortens its service life, and increases maintenance costs; even these bacteria and algae can enter the human body with the water flow, seriously affecting people's health.

[0003] Therefore, developing a composite antibacterial agent to improve the antibacterial properties and durability of PPR pipes is of great significance. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a composite antibacterial agent and its preparation method, as well as PPR pipe.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, the present invention provides a method for preparing a composite antibacterial agent, the method comprising the following steps:

[0007] S1. Mix zinc acetate and glucose and carry out a hydrothermal reaction, then calcine to obtain hollow ZnO microspheres;

[0008] S2. Mix cerium nitrate, urea, and hollow ZnO microspheres and react them, then calcine to obtain ZnO@Ce composite material;

[0009] S3. The composite antibacterial agent is obtained by reacting the mixed ZnO@Ce composite material, silica powder and silane coupling agent.

[0010] In this invention, the composite antibacterial agent, when used in the preparation of PPR pipes, can improve the antibacterial properties and antibacterial durability of the PPR pipes, specifically:

[0011] In the composite antibacterial agent, cerium distorts the local lattice potential field of the hollow ZnO microspheres, generating corresponding intermediate energy levels in the band gap. This allows electrons in the valence band to be excited by longer wavelength light and enter the intermediate energy level, broadening the spectral absorption range of the hollow ZnO microspheres. This improves their photocatalytic efficiency and enhances the antibacterial performance of the composite antibacterial agent and PPR tube. At the same time, the hollow structure of the hollow ZnO microspheres is conducive to the stable adsorption of cerium oxide, maintaining the long-term influence of cerium on the hollow ZnO microspheres and improving the antibacterial durability of the PPR tube.

[0012] When composite antibacterial agents are used to prepare PPR pipes, the addition of silica powder and silane coupling agents not only improves the compatibility between the composite antibacterial agent and random copolymer polypropylene, but also improves the contact angle and hydrophobicity of PPR pipes, thereby improving the antibacterial properties and antibacterial durability of PPR pipes.

[0013] In addition, the hollow structure of the ZnO microspheres makes it difficult for the composite antibacterial agent to aggregate when used to prepare PPR pipes, and it can be uniformly dispersed in random copolymer polypropylene, which is beneficial to improving the antibacterial properties and antibacterial durability of PPR pipes.

[0014] Preferably, in step S1, the mass ratio of zinc acetate to glucose is 1:(0.5-4.5).

[0015] Preferably, in step S1, the mass ratio of zinc acetate to glucose is one or any two of the following: 1:0.5, 1:0.8, 1:1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, 1:3.2, 1:3.5, 1:3.8, 1:4, 1:4.2, 1:4.5.

[0016] More preferably, in step S1, the mass ratio of zinc acetate to glucose is 1:(2-3).

[0017] Preferably, in step S1, the temperature of the hydrothermal reaction is 150-170°C.

[0018] Preferably, in step S1, the hydrothermal reaction takes 5-7 hours.

[0019] Preferably, in step S1, the calcination temperature is 500-700℃, specifically 600-700℃.

[0020] Preferably, in step S1, the calcination time is 3-5 hours, specifically 4-5 hours.

[0021] Preferably, in step S2, the mass ratio of the hollow ZnO microspheres to cerium nitrate is 1:(0.05-0.35).

[0022] Preferably, in step S2, the mass ratio of the hollow ZnO microspheres to cerium nitrate is one or any two of the following: 1:0.05, 1:0.08, 1:0.1, 1:0.12, 1:0.15, 1:0.18, 1:0.2, 1:0.22, 1:0.25, 1:0.28, 1:0.3, 1:0.32, and 1:0.35.

[0023] More preferably, in step S2, the mass ratio of the hollow ZnO microspheres to cerium nitrate is 1:(0.1-0.2).

[0024] Preferably, in step S2, the mass ratio of cerium nitrate to urea is 1:(2-3), specifically 1:(2-2.5).

[0025] Preferably, in step S2, the reaction temperature is 85-95℃, specifically 85-90℃.

[0026] Preferably, in step S2, the reaction time is 5-7 hours, specifically 6-7 hours.

[0027] Preferably, in step S2, the calcination temperature is 700-900℃, specifically 800-850℃.

[0028] Preferably, in step S2, the calcination time is 2-5 hours, specifically 3-4 hours.

[0029] Preferably, in step S3, the mass ratio of the ZnO@Ce composite material, silicon micro powder, and silane coupling agent is 1:(0.3-0.7):(0.3-0.7).

[0030] Preferably, in step S3, the mass ratio of the ZnO@Ce composite material, silicon micropowder, and silane coupling agent is one or any two of the following: 1:0.3:0.4, 1:0.4:0.4, 1:0.5:0.4, 1:0.6:0.4, 1:0.7:0.4, 1:0.4:0.3, 1:0.4:0.5, 1:0.4:0.6, and 1:0.4:0.7.

[0031] More preferably, in step S3, the mass ratio of the ZnO@Ce composite material, silicon micro powder, and silane coupling agent is 1:(0.3-0.5):(0.3-0.5).

[0032] Preferably, in step S3, the reaction is carried out under ultrasonic conditions, wherein the frequency of the ultrasound is 30-40KHz and the power is 200-300W.

[0033] More preferably, the frequency of the ultrasound is 30-35KHz and the power is 200-250W.

[0034] Preferably, in step S3, the reaction time is 0.3-1.5h, specifically 0.5-1.5h.

[0035] Preferably, in step S3, the silane coupling agent includes at least one of γ-aminopropyltriethoxysilane (KH550, CAS No.: 919-30-2) and γ-glycidoxypropyltrimethoxysilane (KH560, CAS No.: 2530-83-8).

[0036] In a second aspect, the present invention provides a composite antibacterial agent prepared by the preparation method described in the first aspect.

[0037] Thirdly, the present invention provides a PPR pipe, which comprises an inner layer, a middle layer and an outer layer from the inside out, wherein the inner layer comprises a composite antibacterial agent as described in the second aspect and random copolymer polypropylene.

[0038] Preferably, the inner layer of the PPR pipe comprises the following components in parts by weight:

[0039] 85-98 parts of random copolymer polypropylene, 2-8 parts of composite antibacterial agent, 2-6 parts of compatibilizer, and 0.05-2 parts of antioxidant.

[0040] Preferably, in the inner layer of the PPR pipe, the random copolymer polypropylene comprises one or any two of the following weight parts: 85 parts, 86 parts, 87 parts, 88 parts, 89 parts, 90 parts, 90.5 parts, 91 parts, 91.5 parts, 92 parts, 92.5 parts, 93 parts, 93.5 parts, 94 parts, 94.5 parts, 95 parts, 96.5 parts, 97 parts, 97.5 parts, and 98 parts; and the composite antibacterial agent comprises 2 parts, 2.2 parts, 2.5 parts, 2.8 parts, 3 parts, 3.2 parts, 3.5 parts, 3.8 parts, 4 parts, 4.2 parts, 4.5 parts, 4.8 parts, 5 parts, 5.2 parts, 5.5 parts, and 5.8 parts. The weight of the compatibilizer is one or any two of the following: 6 parts, 6.2 parts, 6.5 parts, 6.8 parts, 7 parts, 7.5 parts, 8 parts; the weight of the compatibilizer is one or any two of the following: 2 parts, 2.5 parts, 3 parts, 3.2 parts, 3.5 parts, 3.8 parts, 4 parts, 4.2 parts, 4.5 parts, 4.8 parts, 5 parts, 5.5 parts, 6 parts; and the weight of the antioxidant is one or any two of the following: 0.05 parts, 0.08 parts, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts.

[0041] More preferably, the inner layer of the PPR pipe comprises the following components in parts by weight:

[0042] 90-95 parts random copolymer polypropylene, 3-6 parts composite antibacterial agent, 3-5 parts compatibilizer, and 0.1-1 parts antioxidant.

[0043] Preferably, the intermediate layer of the PPR pipe comprises the following components in parts by weight:

[0044] 55-85 parts random copolymer polypropylene, 15-35 parts glass fiber, 3-15 parts compatibilizer, and 0.05-2 parts antioxidant.

[0045] Preferably, in the intermediate layer of the PPR pipe, the random copolymer polypropylene comprises 55 parts, 57 parts, 60 parts, 62 parts, 65 parts, 68 parts, 70 parts, 72 parts, 75 parts, 78 parts, 80 parts, 82 parts, and 85 parts by weight, or any two of these values; the glass fiber comprises 15 parts, 18 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts, 32 parts, and 35 parts by weight, or any two of these values; and the compatibilizer comprises 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, 5.2 parts, and 5.5 parts by weight. The antioxidant can be any one or any two of the following: 5.8 parts, 6 parts, 6.2 parts, 6.5 parts, 6.8 parts, 7 parts, 7.2 parts, 7.5 parts, 7.8 parts, 8 parts, 8.2 parts, 8.5 parts, 8.8 parts, 9 parts, 9.2 parts, 9.5 parts, 9.8 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, and 15 parts by weight; and the antioxidant can be any one or any two of the following: 0.05 parts, 0.08 parts, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, 1.2 parts, 1.5 parts, 1.8 parts, and 2 parts by weight.

[0046] More preferably, the intermediate layer of the PPR pipe comprises the following components in parts by weight:

[0047] 60-80 parts random copolymer polypropylene, 20-30 parts glass fiber, 5-10 parts compatibilizer, and 0.1-1 part antioxidant.

[0048] Preferably, the outer layer of the PPR pipe comprises the following components in parts by weight:

[0049] 95-100 parts of random copolymer polypropylene, 0.01-0.3 parts of nucleating agent, 0.5-5 parts of compatibilizer, and 0.05-2 parts of antioxidant.

[0050] Preferably, in the outer layer of the PPR pipe, the random copolymer polypropylene comprises, by weight, one or any two of the following values: 95 parts, 95.5 parts, 96 parts, 96.5 parts, 97 parts, 97.5 parts, 98 parts, 98.1 parts, 98.2 parts, 98.3 parts, 98.4 parts, 98.5 parts, 98.6 parts, 98.7 parts, 98.8 parts, 98.9 parts, 99 parts, 99.2 parts, 99.5 parts, 99.8 parts, and 100 parts; and the nucleating agent comprises, by weight, 0.01 parts, 0.02 parts, 0.05 parts, 0.08 parts, 0.1 parts, 0.12 parts, 0.15 parts, and 0.18 parts. The weight parts of the compatibilizer are within the range of one or any two of the following: 0.2 parts, 0.22 parts, 0.25 parts, 0.28 parts, and 0.3 parts; the weight parts of the compatibilizer are within the range of one or any two of the following: 0.5 parts, 0.8 parts, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, and 5 parts; and the weight parts of the antioxidant are within the range of one or any two of the following: 0.05 parts, 0.08 parts, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, 1.2 parts, 1.5 parts, 1.8 parts, and 2 parts.

[0051] More preferably, the outer layer of the PPR pipe comprises the following components in parts by weight:

[0052] 98-99 parts random copolymer polypropylene, 0.05-0.1 parts nucleating agent, 1-2 parts compatibilizer, and 0.1-1 parts antioxidant.

[0053] In this invention, the melt flow rate (melt mass flow rate, MFR) of the random copolymer polypropylene measured at 230°C and 2.16 kg is 0.2-0.5 g / 10 min.

[0054] In this invention, the melt flow rate (melt mass flow rate, MFR) of the random copolymer polypropylene measured at 230°C and 2.16 kg is one or any two of the following values: 0.2 g / 10 min, 0.21 g / 10 min, 0.22 g / 10 min, 0.23 g / 10 min, 0.24 g / 10 min, 0.25 g / 10 min, 0.26 g / 10 min, 0.27 g / 10 min, 0.28 g / 10 min, 0.29 g / 10 min, 0.30 g / 10 min, 0.32 g / 10 min, 0.35 g / 10 min, 0.38 g / 10 min, 0.40 g / 10 min, 0.42 g / 10 min, 0.45 g / 10 min, 0.48 g / 10 min, and 0.50 g / 10 min.

[0055] In this invention, the melt flow rate (melt mass flow rate, MFR) of the random copolymer polypropylene is measured according to GB / T 3682.1-2018 standard.

[0056] More preferably, the compatibilizer in the inner and / or middle and / or outer layers of the PPR pipe includes maleic anhydride-grafted polypropylene (MAH-g-PP).

[0057] More preferably, the grafting rate of the maleic anhydride-grafted polypropylene (MAH-g-PP) is 1-1.5%.

[0058] More preferably, the grafting rate of the maleic anhydride-grafted polypropylene (MAH-g-PP) is a range of one or any two of the following: 1%, 1.1%, 1.15%, 1.2%, 1.25%, 1.3%, 1.35%, 1.4%, 1.45%, and 1.5%.

[0059] In this invention, the grafting rate of the maleic anhydride-grafted polypropylene (MAH-g-PP) is measured by acid-base back titration.

[0060] More preferably, the antioxidants in the inner and / or middle and / or outer layers of the PPR pipe include hindered phenolic antioxidants and / or phosphite antioxidants.

[0061] More preferably, the hindered phenolic antioxidant includes at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010), 2,6-di-tert-butyl-4-methylphenol (antioxidant 264), and 1,2-bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine (antioxidant 1024).

[0062] More preferably, the phosphite antioxidant includes triphenyl phosphite and / or tributyl phosphite.

[0063] More preferably, the average length of the glass fiber in the middle layer of the PPR pipe is 2-7 mm, specifically 2-4 mm.

[0064] More preferably, in the intermediate layer of the PPR pipe, the average length of the glass fiber is one or any two of the following values: 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, and 7mm.

[0065] More preferably, the average diameter of the glass fiber in the middle layer of the PPR pipe is 12-16 μm, specifically 13-15 μm.

[0066] More preferably, in the intermediate layer of the PPR pipe, the average diameter of the glass fiber is one or any two of the following values: 12μm, 12.5μm, 13μm, 13.5μm, 14μm, 14.5μm, 15μm, 15.5μm, and 16μm.

[0067] More preferably, the nucleating agent in the outer layer of the PPR pipe includes sorbitol-based nucleating agents and / or photorosin-based nucleating agents.

[0068] More preferably, the sorbitol nucleating agent includes at least one of bis(3,4-dimethylbenzyl)sorbitol (CAS No.: 135861-56-2), 1,3:2,4-di-p-methylbenzyl sorbitol (CAS No.: 54686-97-4), and 1,3:2,4-di-p-methylbenzyl sorbitol (CAS No.: 54686-97-4).

[0069] More preferably, the photorosin nucleating agent includes at least one of methyl dehydroabirate (CAS No.: 1235-74-1) and sodium rosinate (CAS No.: 14351-66-7).

[0070] Preferably, the thickness of the PPR pipe is 2-9 mm.

[0071] Preferably, the thickness of the PPR pipe is one or any two of the following values: 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.2mm, 3.5mm, 3.8mm, 4mm, 4.2mm, 4.5mm, 4.8mm, 5mm, 5.2mm, 5.5mm, 5.8mm, 6mm, 6.2mm, 6.5mm, 6.8mm, 7mm, 7.2mm, 7.5mm, 7.8mm, 8mm, 8.2mm, 8.5mm, 8.8mm, and 9mm.

[0072] More preferably, the thickness of the PPR pipe is 3-5mm, specifically 3.5-4.2mm.

[0073] Preferably, based on the thickness of the PPR pipe, the thickness of the inner layer accounts for ≤40%.

[0074] More preferably, the thickness of the inner layer accounts for 10-40% of the thickness of the PPR pipe.

[0075] Preferably, based on the thickness of the PPR pipe, the thickness of the intermediate layer accounts for ≥30%.

[0076] More preferably, the thickness of the intermediate layer accounts for 30-45% based on the thickness of the PPR pipe.

[0077] Preferably, based on the thickness of the PPR pipe, the thickness of the outer layer accounts for ≥30%.

[0078] More preferably, the outer layer accounts for 30-45% of the thickness of the PPR pipe.

[0079] In this invention, "the thickness percentage of the inner layer based on the thickness of the PPR pipe" refers to the percentage of the inner layer thickness to the PPR pipe thickness; "the thickness percentage of the middle layer based on the thickness of the PPR pipe" refers to the percentage of the middle layer thickness to the PPR pipe thickness; and "the thickness percentage of the outer layer based on the thickness of the PPR pipe" refers to the percentage of the outer layer thickness to the PPR pipe thickness.

[0080] Fourthly, the present invention provides a method for preparing a PPR pipe, the method comprising the following steps:

[0081] (1) Mix the components in the inner layer, middle layer and outer layer respectively to obtain the inner layer mixture, the middle layer mixture and the outer layer mixture;

[0082] (2) The inner layer mixture, the middle layer mixture and the outer layer mixture are extruded using a three-layer co-extrusion die to obtain PPR pipe.

[0083] Preferably, in step (1), the mixing temperature is 170-185°C.

[0084] Preferably, in step (1), the mixing speed is 90-120 r / min.

[0085] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0086] In this invention, the composite antibacterial agent, when used in the preparation of PPR pipes, can improve the antibacterial properties and antibacterial durability of the PPR pipes, specifically:

[0087] In the composite antibacterial agent, cerium distorts the local lattice potential field of the hollow ZnO microspheres, generating corresponding intermediate energy levels in the band gap. This allows electrons in the valence band to be excited by longer wavelength light and enter the intermediate energy level, broadening the spectral absorption range of the hollow ZnO microspheres. This improves their photocatalytic efficiency and enhances the antibacterial performance of the composite antibacterial agent and PPR tube. At the same time, the hollow structure of the hollow ZnO microspheres is conducive to the stable adsorption of cerium oxide, maintaining the long-term influence of cerium on the hollow ZnO microspheres and improving the antibacterial durability of the PPR tube.

[0088] When composite antibacterial agents are used to prepare PPR pipes, the addition of silica powder and silane coupling agents not only improves the compatibility between the composite antibacterial agent and random copolymer polypropylene, but also improves the contact angle and hydrophobicity of PPR pipes, thereby improving the antibacterial properties and antibacterial durability of PPR pipes.

[0089] In addition, the hollow structure of the ZnO microspheres makes it difficult for the composite antibacterial agent to aggregate when used to prepare PPR pipes, and it can be uniformly dispersed in random copolymer polypropylene, which is beneficial to improving the antibacterial properties and antibacterial durability of PPR pipes. Attached Figure Description

[0090] Figure 1 This is a SEM image of the hollow ZnO microspheres in Example 1.

[0091] Figure 2 This is a TEM image of the hollow ZnO microspheres in Example 1. Detailed Implementation

[0092] 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.

[0093] In the following examples, experimental methods without specific conditions are generally performed under conventional conditions in the art or as recommended by the manufacturer. Unless otherwise specified, all raw materials and reagents used are commercially available from the general market. Furthermore, unless otherwise specified, "parts" and "%" refer to mass measurements.

[0094] The reagents used in the various embodiments and comparative examples of this invention are as follows:

[0095] Silica micro powder-1, HY-GA-2, Shenzhen Haiyang Powder;

[0096] Silica micropowder-2, NOVOPOWDER DF, Jiangsu Lianrui New Materials;

[0097] Silane coupling agent-1, γ-aminopropyltriethoxysilane (KH550, CAS No.: 919-30-2), commercially available;

[0098] Silane coupling agent-2, γ-glycidoxypropyltrimethoxysilane (KH560, CAS No.: 2530-83-8), commercially available;

[0099] Random copolymer polypropylene-1, PPR-1, 4220, Yanshan Petrochemical, the melt flow rate (melt mass flow rate, MFR) measured at 230℃ and 2.16kg was 0.24g / 10min.

[0100] The melt flow rate (melt mass flow rate, MFR) of random copolymer polypropylene-2, PPR-2, T4401, Dushanzi Petrochemical, measured at 230℃ and 2.16kg was 0.25g / 10min.

[0101] Compatibilizer-1, maleic anhydride-grafted polypropylene, MAH-g-PP-1, maleic anhydride grafting rate 1.2%, 18722, SK Chemicals, South Korea;

[0102] Compatibilizer-2, maleic anhydride-grafted polypropylene, MAH-g-PP-2, maleic anhydride grafting rate 1%, PO 1015, ExxonMobil;

[0103] Antioxidant-1, hindered phenolic antioxidant, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010), commercially available;

[0104] Antioxidant-2, a phosphite antioxidant, triphenyl phosphite, commercially available;

[0105] Glass fiber-1, average length 3mm, average diameter 13μm, ECS13-03-508A, China Jushi Co., Ltd.;

[0106] Glass fiber-2, average length 3mm, average diameter 14μm, ECS14-03-508S, China Jushi Co., Ltd.;

[0107] Nucleating agent-1, sorbitol-based nucleating agent, bis(3,4-dimethylbenzyl)sorbitol (CAS No.: 135861-56-2), commercially available;

[0108] Nucleating agent-2, photorosin nucleating agent, sodium rosinate (CAS No.: 14351-66-7), commercially available;

[0109] In this invention, the melt flow rate (melt mass flow rate, MFR) of the random copolymer polypropylene is measured according to GB / T 3682.1-2018 standard;

[0110] In this invention, the grafting rate of the maleic anhydride-grafted polypropylene (MAH-g-PP) is measured by acid-base back titration. Specifically, acetone is used as the solvent to remove unreacted maleic anhydride from 5g of maleic anhydride-grafted polypropylene (MAH-g-PP) by Soxhlet extraction for 48h. Then, the treated MAH-g-PP is dissolved in 100mL of organic solvent (xylene) at 130℃. An excess of strong base (20mL of 0.1mol / L sodium hydroxide solution) is added to hydrolyze the anhydride groups. The unreacted strong base is then back titrated with a strong acid (0.1mol / L hydrochloric acid). Finally, the maleic anhydride grafting rate of MAH-g-PP is calculated based on the results.

[0111] Example 1

[0112] This embodiment provides a composite antibacterial agent, the preparation method of which includes the following steps:

[0113] S1. Add 130g of zinc acetate and 325g of glucose to deionized water, transfer to a reaction vessel, and carry out a hydrothermal reaction at 160℃ for 6 hours. After the reaction is completed, allow it to cool naturally to room temperature, centrifuge, wash with deionized water, dry at 80℃ for 8 hours, and then calcine at 600℃ for 4 hours in a muffle furnace to obtain hollow ZnO microspheres, as shown below. Figure 1-2 As shown;

[0114] S2. In an ethanol-water solution (volume ratio of deionized water to ethanol is 1:1), cerium nitrate and urea were added and stirred to mix. Then, 40g of hollow ZnO microspheres were added and ultrasonically dispersed for 30min. The mixture was heated in a 90℃ water bath for 6h under a stirring speed of 600rpm. After the reaction was completed, the mixture was naturally cooled to room temperature, centrifuged, washed with deionized water, dried at 60℃ for 8h, and then calcined in a muffle furnace at 800℃ for 3h to obtain the ZnO@Ce composite material.

[0115] S3. Add 37.5g of ZnO@Ce composite material and 15g of silica powder-1 to anhydrous ethanol solution, and disperse by ultrasonication for 30min. Then, under ultrasonic conditions (35KHz frequency, 250W power), add 15g of silane coupling agent-1 (γ-aminopropyltriethoxysilane, KH550) and react for 0.5h. Centrifuge and vacuum dry at 60℃ for 8h to obtain the composite antibacterial agent.

[0116] In step S1, the mass ratio of zinc acetate to glucose is 1:2.5, and the ratio of the total mass of zinc acetate and glucose to the volume of deionized water is 11.5g:100mL.

[0117] In step S2, the mass ratio of the hollow ZnO microspheres to cerium nitrate is 1:0.1, the mass ratio of cerium nitrate to urea is 1:2.5, and the mass ratio of the hollow ZnO microspheres to the volume of the ethanol aqueous solution is 1g:100mL.

[0118] In step S3, the mass ratio of the ZnO@Ce composite material, silicon micro powder-1 and silane coupling agent-1 is 1:0.4:0.4, and the ratio of the total mass of the ZnO@Ce composite material and silicon micro powder-1 to the volume of the anhydrous ethanol solution is 5g:100mL.

[0119] This embodiment also provides a PPR pipe, which includes an inner layer, a middle layer and an outer layer from the inside out. The thickness of the PPR pipe is 3.5 mm, the thickness of the inner layer is 1.1 mm, the thickness of the middle layer is 1.3 mm and the thickness of the outer layer is 1.1 mm.

[0120] The inner layer of the PPR pipe comprises the following components in parts by weight:

[0121] 90 parts of random copolymer polypropylene-1 (PPR-1), 6 parts of the above-prepared composite antibacterial agent, 3 parts of compatibilizer-1 (MAH-g-PP-1), and 1 part of antioxidant-1 (antioxidant 1010).

[0122] The intermediate layer of the PPR pipe comprises the following components in parts by weight:

[0123] Random copolymer polypropylene-1 (PPR-1) 60 parts, glass fiber-1 30 parts, compatibilizer-1 (MAH-g-PP-1) 5 parts, antioxidant-1 (antioxidant 1010) 1 part;

[0124] The outer layer of the PPR pipe comprises the following components in parts by weight:

[0125] Random copolymer polypropylene-1 (PPR-1) 98 parts, nucleating agent-1 0.1 parts, compatibilizer-1 (MAH-g-PP-1) 1 part, antioxidant-1 (antioxidant 1010) 1 part;

[0126] The above-mentioned method for preparing PPR pipes includes the following steps:

[0127] (1) Mix the components in the inner layer, melt extrude them using a twin-screw extruder at 180℃ and 100r / min, granulate them, and obtain the inner layer mixture for later use;

[0128] The components in the mixed intermediate layer are melt-extruded and granulated using a twin-screw extruder at 180°C and 100 r / min to obtain the intermediate layer mixture for later use; wherein, glass fiber-1 is added through the side feed port of the twin-screw extruder;

[0129] The components in the outer layer are mixed and melt-extruded using a twin-screw extruder at 180°C and 100 r / min, then granulated to obtain the outer layer mixture for later use.

[0130] (2) The inner layer mixture, the middle layer mixture and the outer layer mixture are extruded by a single screw extruder (200℃, 80r / min) using a three-layer co-extrusion die. The mixture is then vacuum-formed, cooled, drawn and cut to obtain the PPR pipe.

[0131] Examples 2-5

[0132] Examples 2-5 provide different composite antibacterial agents and PPR pipes. The difference between them and Example 1 is that the mass ratio of zinc acetate to glucose is different in step S1. The rest are the same as in Example 1, as shown in the table below:

[0133] Table 1. Mass ratio of zinc acetate and glucose in Examples 1-5

[0134]

[0135] Examples 6-8 and Comparative Examples 1-2

[0136] Examples 6-8 and Comparative Examples 1-2 provide different composite antibacterial agents and PPR pipes. The difference between them and Example 1 is that the mass ratio of hollow ZnO microspheres to cerium nitrate is different in step S2. The rest are the same as in Example 1, as shown in the table below:

[0137] Table 2. Mass ratio of hollow ZnO microspheres and cerium nitrate in Examples 1, 6-8 and Comparative Examples 1-2.

[0138]

[0139] Note: In the table above, “1:0.1 (cerium trichloride)” in Comparative Example 2 means that Comparative Example 2 uses cerium trichloride instead of cerium nitrate in Example 1, and the mass ratio of hollow ZnO microspheres to cerium trichloride is 1:0.1.

[0140] Examples 9-16 and Comparative Examples 3-5

[0141] Examples 9-16 and Comparative Examples 3-5 provide different composite antibacterial agents and PPR pipes. The difference between them and Example 1 is that in step S3, the mass ratio of ZnO@Ce composite material, silica powder-1, and silane coupling agent-1 is different. The rest are the same as in Example 1, as shown in the table below:

[0142] Table 3. Mass ratios of ZnO@Ce composite material, silicon micropowder-1, and silane coupling agent-1 in Examples 1, 9-16, and Comparative Examples 3-5

[0143]

[0144] Note: In the table above, “1:0.4 (silicon micro powder-2):0.4” in Example 15 means that silicon micro powder-2 is used in Example 15 instead of silicon micro powder-1 in Example 1, and the mass ratio of ZnO@Ce composite material, silicon micro powder-2 and silane coupling agent-1 is 1:0.4:0.4.

[0145] The “1:0.4:0.4 (silane coupling agent-2)” in Example 16 means that in Example 16, silane coupling agent-2 is used instead of silane coupling agent-1 in Example 1, and the mass ratio of ZnO@Ce composite material, silicon micro powder-1 and silane coupling agent-2 is 1:0.4:0.4.

[0146] Example 17

[0147] This embodiment provides a composite antibacterial agent, the preparation method of which is the same as that in Example 1;

[0148] This embodiment also provides a PPR pipe, which includes an inner layer, a middle layer and an outer layer from the inside out. The thickness of the PPR pipe is 4.2 mm, the thickness of the inner layer is 1.3 mm, the thickness of the middle layer is 1.5 mm and the thickness of the outer layer is 1.4 mm.

[0149] The inner layer of the PPR pipe comprises the following components in parts by weight:

[0150] 95 parts of random copolymer polypropylene-2 ​​(PPR-2), 3 parts of the above-prepared composite antibacterial agent, 5 parts of compatibilizer-2 (PP-g-MAH-2), and 0.1 parts of antioxidant-2 (triphenyl phosphite);

[0151] The intermediate layer of the PPR pipe comprises the following components in parts by weight:

[0152] Random copolymer polypropylene-2 ​​(PPR-2) 80 parts, glass fiber-2 20 parts, compatibilizer-2 (PP-g-MAH-2) 10 parts, antioxidant-2 (triphenyl phosphite) 0.1 parts;

[0153] The outer layer of the PPR pipe comprises the following components in parts by weight:

[0154] Random copolymer polypropylene-2 ​​(PPR-2) 99 parts, nucleating agent-2 0.05 parts, compatibilizer-2 (PP-g-MAH-2) 2 parts, antioxidant-2 (triphenyl phosphite) 0.1 parts;

[0155] The preparation method of the above PPR pipe is the same as that in Example 1.

[0156] Comparative Example 6

[0157] This comparative example provides a composite antibacterial agent, the preparation method of which includes the following steps:

[0158] Add 130g of zinc acetate and 325g of glucose to deionized water, transfer to a reaction vessel, and carry out a hydrothermal reaction at 160℃ for 6 hours. After the reaction is completed, cool naturally to room temperature, centrifuge, wash with deionized water, dry at 80℃ for 8 hours, and then calcine at 600℃ for 4 hours in a muffle furnace to obtain hollow ZnO microspheres, which are used as a composite antibacterial agent.

[0159] The mass ratio of zinc acetate to glucose is 1:2.5, and the ratio of the total mass of zinc acetate and glucose to the volume of deionized water is 11.5g:100mL.

[0160] This embodiment also provides a PPR pipe and its preparation method, which is consistent with Embodiment 1.

[0161] Performance testing

[0162] The following performance tests were performed on the PPR pipes of each embodiment and comparative example:

[0163] 1. Antibacterial test:

[0164] According to the JC / T 939-2004 standard "5.1 Antibacterial Performance Test", the antibacterial rate (%) of each example or comparative example PPR pipe was tested; the higher the antibacterial rate, the stronger the antibacterial property of the PPR pipe.

[0165] 2. Antibacterial durability test:

[0166] According to the JC / T 939-2004 standard "5.2 Antibacterial Durability Test", the antibacterial rate (%) of each example or comparative example PPR pipe was tested; the higher the antibacterial rate, the stronger the antibacterial durability of the PPR pipe.

[0167] 3. Contact angle:

[0168] Take the inner layer mixture (prepared from the inner layer components) of each embodiment or comparative example, and injection mold a sample with a length of 300 mm, a width of 25 mm, and a thickness of 0.5 mm at 190 °C. Then, perform contact angle testing according to GB / T 30693-2014 standard.

[0169] 4. Antibacterial rate after 95℃ / 165h hydraulic test: According to GB / T 18742.2-2017 standard, the PPR pipes of each embodiment or comparative example were treated at 95℃ and 3.8MPa hydrostatic pressure for 165h. Then, the antibacterial rate (%) of the PPR pipes was tested according to JC / T 939-2004 "5.1 Antibacterial Performance Test". This was used as the antibacterial rate (%) of the PPR pipes of each embodiment or comparative example after the 95℃ / 165h hydraulic test.

[0170] The experimental results are shown in the table below:

[0171] Table 4. Performance test results of PPR pipes in each embodiment and comparative example.

[0172]

[0173] As shown in Table 4, the composite antibacterial agent of the present invention can improve the antibacterial properties and antibacterial durability of PPR pipes when used in the preparation of PPR pipes.

[0174] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended 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. A method for preparing a composite antibacterial agent, characterized in that, The preparation method includes the following steps: S1. Mix zinc acetate and glucose and carry out a hydrothermal reaction, then calcine to obtain hollow ZnO microspheres; S2. Mix cerium nitrate, urea, and hollow ZnO microspheres and react them, then calcine to obtain ZnO@Ce composite material; S3. The composite antibacterial agent is obtained by reacting the mixed ZnO@Ce composite material, silica powder and silane coupling agent. In step S1, the mass ratio of zinc acetate to glucose is 1:(0.5-4.5), the hydrothermal reaction temperature is 150-170℃, and the calcination temperature is 500-700℃. In step S2, the mass ratio of the hollow ZnO microspheres to cerium nitrate is 1:(0.05-0.35), the mass ratio of cerium nitrate to urea is 1:(2-3), the reaction temperature is 85-95℃, and the calcination temperature is 700-900℃. In step S3, the mass ratio of the ZnO@Ce composite material, silicon micro powder and silane coupling agent is 1:(0.3-0.7):(0.3-0.7), and the reaction is carried out under ultrasonic conditions, with the ultrasonic frequency being 30-40KHz and the power being 200-300W.

2. The preparation method of the composite antibacterial agent as described in claim 1, characterized in that, Includes at least one of the following (1)-(3): (1) In step S1, the mass ratio of zinc acetate to glucose is 1:(2-3); (2) In step S2, the mass ratio of the hollow ZnO microspheres to cerium nitrate is 1:(0.1-0.2); (3) In step S3, the mass ratio of the ZnO@Ce composite material, silicon micro powder and silane coupling agent is 1:(0.3-0.5):(0.3-0.5).

3. The preparation method of the composite antibacterial agent as described in claim 1, characterized in that, In step S3, the silane coupling agent includes at least one of γ-aminopropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane.

4. A composite antibacterial agent, characterized in that, It is prepared by any one of the preparation methods described in claims 1-3.

5. A PPR pipe, characterized in that, The PPR pipe comprises an inner layer, a middle layer, and an outer layer from the inside out, wherein the inner layer comprises the composite antibacterial agent as described in claim 4 and random copolymer polypropylene.

6. The PPR pipe as described in claim 5, characterized in that, Includes at least one of the following (1)-(4): (1) The inner layer of the PPR pipe comprises the following components in parts by weight: 85-98 parts of random copolymer polypropylene, 2-8 parts of composite antibacterial agent, 2-6 parts of compatibilizer, and 0.05-2 parts of antioxidant; (2) The intermediate layer of the PPR pipe comprises the following components in parts by weight: Random copolymer polypropylene 55-85 parts, glass fiber 15-35 parts, compatibilizer 3-15 parts, antioxidant 0.05-2 parts; (3) The outer layer of the PPR pipe comprises the following components in parts by weight: Random copolymer polypropylene 95-100 parts, nucleating agent 0.01-0.3 parts, compatibilizer 0.5-5 parts, antioxidant 0.05-2 parts; (4) The thickness of the PPR pipe is 2-9mm.

7. The PPR pipe as described in claim 6, characterized in that, Includes at least one of the following (1)-(5): (1) The compatibilizer in the inner and / or middle and / or outer layers of the PPR pipe includes maleic anhydride-grafted polypropylene. (2) In the inner layer and / or middle layer and / or outer layer of the PPR pipe, the antioxidants include hindered phenolic antioxidants and / or phosphite antioxidants; (3) In the intermediate layer of the PPR pipe, the average length of the glass fiber is 2-7 mm; (4) In the intermediate layer of the PPR pipe, the average diameter of the glass fiber is 12-16 μm; (5) The nucleating agent in the outer layer of the PPR pipe includes sorbitol-based nucleating agents and / or photorosin-based nucleating agents.

8. The PPR pipe as described in claim 5, characterized in that, Includes at least one of the following (1)-(3): (1) Based on the thickness of the PPR pipe, the thickness of the inner layer accounts for 10-40%; (2) Based on the thickness of the PPR pipe, the thickness of the intermediate layer accounts for 30-45%; (3) Based on the thickness of the PPR pipe, the thickness of the outer layer accounts for 30-45%.

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