Mildew-proof antibacterial plastic and preparation method thereof

Abstract

The invention discloses mildew-proof and antibacterial plastic and a preparation method thereof, and relates to the technical field of plastic. The modified mixed crystal phase TiO2 / C3N4 efficient antibacterial agent is prepared by taking a carbon / nitrogen source precursor and different titanium sources as raw materials and then performing calcination modification treatment, so that the prepared plastic is high in antibacterial and mildew-proof properties, good in durability, good in biocompatibility, low in toxicity and more environment-friendly. The fly ash, the efficient antibacterial agent and the quaternized polyvinyl alcohol are adopted as master batches and are extruded with the ultra-high molecular weight polyethylene, the high-density polyethylene and the silicone oil, the silicone oil is poor in compatibility with a matrix and migrates to the surface of the material, a hydrophobic layer is formed on the surface of a composite film, adhesion of microorganisms to the surface of plastic is preliminarily reduced, and the antibacterial property of the plastic is improved. The antibacterial property of the plastic is improved.

Description

Technical Field

[0001] The invention relates to the technical field of plastics, in particular to mildew-proof and antibacterial plastic and a preparation method thereof. Background Art

[0002] Plastics are widely used in packaging films, building materials, wires and cables, foaming materials, sealing materials, fibers, etc. Traditional plastics have poor antibacterial and mildew-proof properties, which hinders their application in food packaging, sanitary products, medical fields, etc. Inorganic antibacterial agents are non-toxic and environmentally friendly, have fast sterilization speed, and excellent mildew-proof effect, and have important applications in the antibacterial and mildew-proof inventions of polymer materials.

[0003] Directly adding inorganic antimicrobial agents to plastic products will reduce the performance of the material, cause serious color changes, and when the plastic comes into contact with water, silver-based antimicrobial agents, for example, will precipitate, affecting the long-term antimicrobial and anti-mildew properties of the material.

[0004] Graphitic carbon nitride (C3N4), as an analog of graphite and metal-free polymer n-type semiconductor, has a triazine stacking two-dimensional (2D) structure connected by tertiary amines, a band gap of about 2.7 eV, and a corresponding light wavelength of about 460 nm. It is a potential visible light photosensitizer. However, the low specific surface area, poor visible light absorption and high recombination rate of photoinduced electron-hole pairs of C3N4 limit its antibacterial activity to a certain extent. Summary of the invention

[0005] The purpose of the present invention is to provide a mildew-proof and antibacterial plastic and a preparation method thereof, so as to solve the problems existing in the prior art.

[0006] In order to solve the above technical problems, the present invention provides the following technical solution: a method for preparing mildew-proof and antibacterial plastics, comprising the following preparation steps:

[0007] (1) A urea aqueous solution with a mass concentration of 75 to 85% and anatase titanium dioxide are mixed at a solid-liquid ratio of 1:2 to 1:5 and wet-ground. After the wet-ground grinding is completed, the mixture is mixed according to n (urea): n (Ti 3+ )=1~10: 1~10 add titanium trichloride solution, stir at 100~200rpm for 10min, spray granulate at a pressure of 0.5~1.5MPa and 100~110℃, dry at 120~170℃ for 1~4h to obtain mixed powder;

[0008] (2) The mixed powder is placed in a gas grinder, and the gas jet spray device of the gas grinder is turned on to make the mixed powder collide continuously and grind for 25 to 35 minutes to obtain a highly effective antibacterial agent;

[0009] (3) mixing a high-efficiency antibacterial agent, fly ash, and a 20-35 wt% quaternary ammonium polyvinyl alcohol aqueous solution, adding a 12% NaOH solution by mass, adjusting the pH to 12, stirring at 70° C. and 400 r / min for 10 min to obtain a mixed gel, drying the mixed gel at 95° C. to a water content of less than 5%, crushing, and passing through a 200-mesh sieve to obtain a masterbatch;

[0010] (4) Mix the masterbatch, polyethylene and silicone oil in a mass ratio of 20-35:50-75:6-8, and extrude at 190° C. to 220° C. to obtain a mildew-proof and antibacterial plastic.

[0011] Furthermore, the rotation speed of the wet grinding in step (1) is 100 rpm-500 rpm, and the time of the wet grinding is 10 min-90 min.

[0012] Furthermore, the titanium trichloride solution in step (1) is prepared by dissolving titanium trichloride in 3 wt % hydrochloric acid to obtain a solution in which titanium trichloride accounts for 20% by volume, and then adding a saturated sodium chloride aqueous solution to form a 0.15 mol / L titanium trichloride solution.

[0013] Furthermore, the gas used in the gas injection device in step (2) is prepared by mixing the precursor copper acetylacetonate volatiles and argon gas in a volume ratio of 1:10; the injection speed of the gas injection device is 20-30 m / s, and the gas temperature used in the gas injection device is 400-550°C.

[0014] Furthermore, in step (3), the quaternized polyvinyl alcohol has a quaternized substitution degree molar ratio of 49.8±3.5%.

[0015] Furthermore, the preparation method of quaternized polyvinyl alcohol in step (3) comprises the following steps: slowly adding 0.5-1g of polyvinyl alcohol into a flask at room temperature and starting stirring, heating in a water bath, and gradually raising the temperature of the water bath to 80-95°C to completely dissolve the polyvinyl alcohol; cooling the completely dissolved polyvinyl alcohol to room temperature, adding 3-5g of epoxypropyltrimethylammonium chloride into the flask, and stirring to allow the reactants to fully contact; slowly adding a potassium hydroxide solution with a mass concentration of 6-15% into the round-bottom flask every 6-15s, adding 4-5 drops each time, and the total amount of potassium hydroxide solution is 1-2mL; after the reaction is completed, cooling the product to room temperature, pouring it into a pre-prepared beaker containing 20mL of isopropanol solution, stirring continuously with a glass rod until a white precipitate is precipitated, leaving the solution in the beaker to stand at room temperature for 40-70min, and then filtering it with suction. The white precipitate is the target product, quaternized polyvinyl alcohol, which is vacuum dried at 60°C to constant weight and then crushed.

[0016] Furthermore, in step (3), the mass ratio of the high-efficiency antibacterial agent, fly ash, and quaternized polyvinyl alcohol is 10-16:3-8:40-70.

[0017] Furthermore, the polyethylene in step (4) is an ultra-high molecular weight polyethylene with a weight average molecular weight of 5 million to 7 million and a carbonyl group with a molecular weight of 0.941 to 0.960 g / cm 3 The mass ratio of high-density polyethylene is 10-20:5-15.

[0018] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0019] The present invention uses carbon / nitrogen source precursors and different titanium sources as raw materials, and then calcination and modification treatment is performed to prepare a modified mixed crystal phase TiO2 / C3N4 high-efficiency antibacterial agent, so that the prepared plastic has strong antibacterial and mildew resistance, good durability, good biocompatibility, low toxicity, and is more environmentally friendly. The calcination in the present invention adopts the form of hot air, which can achieve nano-ization and modification in one step. The composite of C3N4 and titanium dioxide and the overall nanoparticle size increase the specific surface area of ​​the antibacterial agent, and then can more fully contact with microorganisms, thereby accelerating the sterilization process and improving the antibacterial and mildew resistance of plastics. The nano-level antibacterial agent can greatly improve the dispersibility in plastics, and the hot air is formed by organic copper, and at high temperature, copper element doping modification is achieved, which helps TiO2 to form more stable photogenerated electron-hole pairs, thereby synergistically improving the catalytic antibacterial and mildew resistance.

[0020] The present invention adopts fly ash, a high-efficiency antibacterial agent and quaternized polyvinyl alcohol as master batches. In an alkaline environment, a dense protective film on the surface of the fly ash is destroyed, the activity of the fly ash is improved, and some surface particles are negatively charged, which are electrostatically combined with cations of the quaternized polyvinyl alcohol to achieve compatibility between materials. The master batch is extruded with ultra-high molecular weight polyethylene, high-density polyethylene and silicone oil. The silicone oil has poor compatibility with the matrix and migrates to the surface of the material to form a hydrophobic layer on the surface of the composite film, which preliminarily reduces the adhesion of microorganisms on the plastic surface and improves the antibacterial property of the plastic. DETAILED DESCRIPTION

[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0022] In order to more clearly illustrate the method provided by the present invention, the following examples are used to describe in detail the test methods of various anti-mildew and antibacterial indicators prepared in the following examples are as follows:

[0023] Antibacterial property: The test method refers to GB / T31402-2015 "Test method for antibacterial performance of plastic surface" standard. Experiment: nutrient agar method. The test plastic size is 50mm×50mm and the thickness is 4mm. The test bacteria are Escherichia coli ATCC8739 and Staphylococcus aureus ATCC6538. The selected bacteria concentration is 5.0×10 5 The dilution with cfu / mL was used as the experimental bacterial solution, and the test results are shown in Table 1.

[0024] Mildew resistance: The test method refers to GB / T24128-2018 "Mold resistance of plastic mildew inhibitors" standard. Experiment: nutrient agar method. The test plastic size is 40mm×40mm and the thickness is 4mm. The main test strains are Aspergillus niger ATCC6275, Penicillium variotii CBS628.66, Penicillium funiculum ATCC9644, Trichoderma longifolia ATCC13631 and Mucor globosum ATCC6205. The above strains are used to culture and make a concentration of 6.0×10 6 Before use, the five kinds of fungal spore suspensions were mixed to prepare a mixed bacterial solution.

[0025] Example 1

[0026] (1) dissolving titanium trichloride in 3 wt % hydrochloric acid to obtain a solution in which titanium trichloride accounts for 20 % by volume, and then adding a saturated sodium chloride aqueous solution to form a 0.15 mol / L titanium trichloride solution; mixing a urea aqueous solution with a mass concentration of 75 % and anatase-type titanium dioxide at a solid-liquid ratio of 1:2, and performing wet grinding at a rotation speed of 100 rpm for 90 min. After the wet grinding is completed, the mixture is stirred at 40 °C for 2 hours according to the formula: n (urea): n (Ti 3+ )=10:1, add titanium trichloride solution, stir at 100rpm for 10min, spray granulate at a pressure of 0.5MPa and 100℃, and dry at 170℃ for 1h to obtain mixed powder;

[0027] (2) placing the mixed powder in a gas grinder, turning on the gas jet device of the gas grinder, with a jet speed of 20 m / s and a gas temperature of 550° C., so that the mixed powder is continuously collided and ground for 25 minutes to obtain a highly effective antibacterial agent; the gas used in the gas jet device is a mixture of precursor copper acetylacetonate volatiles and argon gas at a volume ratio of 1:10;

[0028] (3) A high-efficiency antibacterial agent, fly ash, and a 20 wt% quaternary ammonium polyvinyl alcohol aqueous solution are mixed, a 12% mass fraction NaOH solution is added dropwise, the pH is adjusted to 12, and the mixture is stirred at 70° C. and 400 r / min for 10 min to obtain a mixed gel, and the mixed gel is dried at 95° C. to a water content of less than 5%, crushed, and sieved through a 200-mesh sieve to obtain a masterbatch; the mass ratio of the high-efficiency antibacterial agent, fly ash, and quaternary ammonium polyvinyl alcohol is 10:3:40;

[0029] (4) Mix the masterbatch, polyethylene and silicone oil in a mass ratio of 20:50:6, extrude at 190°C to 220°C to obtain a mildew-proof and antibacterial plastic; the polyethylene is an ultra-high molecular weight polyethylene with a weight average molecular weight of 5 million and a 0.941 g / cm 3 High-density polyethylene at a mass ratio of 10:5.

[0030] Example 2

[0031] (1) dissolving titanium trichloride in 3 wt % hydrochloric acid to obtain a solution in which titanium trichloride accounts for 20% by volume, and then adding a saturated sodium chloride aqueous solution to form a 0.15 mol / L titanium trichloride solution; mixing a urea aqueous solution with a mass concentration of 77.5% and anatase-type titanium dioxide at a solid-liquid ratio of 1:2, and performing wet grinding at a rotation speed of 200 rpm for 30 min. After the wet grinding is completed, the mixture is mixed according to n (urea): n (Ti 3+ )=10:2, add titanium trichloride solution, stir at 100rpm for 10min, spray granulate at a pressure of 0.5MPa and 100℃, and dry at 170℃ for 1h to obtain a mixed powder;

[0032] (2) placing the mixed powder in a gas grinder, turning on the gas jet device of the gas grinder, with a jet speed of 20 m / s and a gas temperature of 550° C., so that the mixed powder is continuously collided and ground for 25 minutes to obtain a highly effective antibacterial agent; the gas used in the gas jet device is a mixture of precursor copper acetylacetonate volatiles and argon gas at a volume ratio of 1:10;

[0033] (3) A high-efficiency antibacterial agent, fly ash, and a 22 wt% quaternary ammonium polyvinyl alcohol aqueous solution were mixed, a 12% mass fraction NaOH solution was added dropwise, the pH was adjusted to 12, and the mixture was stirred at 70°C and 400 r / min for 10 min to obtain a mixed gel, and the mixed gel was dried at 95°C until the water content was less than 5%, crushed, and passed through a 200-mesh sieve to obtain a masterbatch; the mass ratio of the high-efficiency antibacterial agent, fly ash, and quaternary ammonium polyvinyl alcohol was 11:4:45;

[0034] (4) Mix the masterbatch, polyethylene and silicone oil in a mass ratio of 20 to 35:55:6, extrude at 190°C to 220°C, and obtain a mildew-proof and antibacterial plastic; the polyethylene is an ultra-high molecular weight polyethylene with a weight average molecular weight of 5 million and a 0.951 g / cm 3 High-density polyethylene at a mass ratio of 12:5.

[0035] Example 3

[0036] (1) dissolving titanium trichloride in 3 wt % hydrochloric acid to obtain a solution in which titanium trichloride accounts for 20% by volume, and then adding a saturated sodium chloride aqueous solution to form a 0.15 mol / L titanium trichloride solution; mixing an 80% urea aqueous solution and anatase titanium dioxide at a solid-liquid ratio of 1:4, and performing wet grinding at a rotation speed of 400 rpm for 50 min. After the wet grinding is completed, the mixture is stirred at 400 rpm for 50 min according to the formula: n (urea): n (Ti 3+ )=8:2, add titanium trichloride solution, stir at 200rpm for 10min, spray granulate at a pressure of 1.5MPa and 110℃, and dry at 170℃ for 4h to obtain a mixed powder;

[0037] (2) placing the mixed powder in a gas grinder, turning on the gas jet device of the gas grinder, with a jet speed of 30 m / s and a gas temperature of 550° C., so that the mixed powder is continuously collided and ground for 35 minutes to obtain a highly effective antibacterial agent; the gas used in the gas jet device is a mixture of precursor copper acetylacetonate volatiles and argon gas at a volume ratio of 1:10;

[0038] (3) A high-efficiency antibacterial agent, fly ash, and 28 wt% quaternary ammonium polyvinyl alcohol aqueous solution were mixed, a 12% mass fraction NaOH solution was added dropwise, the pH was adjusted to 12, and the mixture was stirred at 70°C and 400 r / min for 10 min to obtain a mixed gel, and the mixed gel was dried at 95°C until the water content was less than 5%, crushed, and passed through a 200-mesh sieve to obtain a masterbatch; the mass ratio of the high-efficiency antibacterial agent, fly ash, and quaternary ammonium polyvinyl alcohol was 13:5.5:55;

[0039] (4) Mix the masterbatch, polyethylene and silicone oil in a mass ratio of 30:62:7, extrude at 190°C to 220°C, and obtain a mildew-proof and antibacterial plastic; the polyethylene is an ultra-high molecular weight polyethylene with a weight average molecular weight of 6 million and a 0.955 g / cm 3 High-density polyethylene at a mass ratio of 20:5.

[0040] Example 4

[0041] (1) dissolving titanium trichloride in 3 wt % hydrochloric acid to obtain a solution in which titanium trichloride accounts for 20 vol%, and then adding a saturated sodium chloride aqueous solution to form a 0.15 mol / L titanium trichloride solution; mixing an 82 wt % urea aqueous solution and anatase titanium dioxide at a solid-liquid ratio of 1:5, and performing wet grinding at a rotation speed of 500 rpm for 28 min. After the wet grinding is completed, the mixture is stirred at 40 °C for 2 hours according to the formula: n (urea): n (Ti 3+ )=10:5, add titanium trichloride solution, stir at 200rpm for 10min, spray granulate at a pressure of 1.5MPa and 110℃, and dry at 170℃ for 3h to obtain a mixed powder;

[0042] (2) placing the mixed powder in a gas grinder, turning on the gas jet device of the gas grinder, with a jet speed of 30 m / s and a gas temperature of 550° C., so that the mixed powder is continuously collided and ground for 35 minutes to obtain a highly effective antibacterial agent; the gas used in the gas jet device is a mixture of precursor copper acetylacetonate volatiles and argon gas at a volume ratio of 1:10;

[0043] (3) A high-efficiency antibacterial agent, fly ash, and a 32 wt% quaternary ammonium polyvinyl alcohol aqueous solution were mixed, a 12% mass fraction NaOH solution was added dropwise, the pH was adjusted to 12, and the mixture was stirred at 70°C and 400 r / min for 10 min to obtain a mixed gel, and the mixed gel was dried at 95°C until the water content was less than 5%, crushed, and passed through a 200 mesh sieve to obtain a masterbatch; the mass ratio of the high-efficiency antibacterial agent, fly ash, and quaternary ammonium polyvinyl alcohol was 15:5.5:60;

[0044] (4) Mix the masterbatch, polyethylene and silicone oil in a mass ratio of 30:70:7, extrude at 190°C to 220°C to obtain a mildew-proof and antibacterial plastic; the polyethylene is an ultra-high molecular weight polyethylene with a weight average molecular weight of 7 million and a 0.960 g / cm 3 High-density polyethylene at a mass ratio of 20:15.

[0045] Example 5

[0046] (1) dissolving titanium trichloride in 3 wt % hydrochloric acid to obtain a solution in which titanium trichloride accounts for 20 % by volume, and then adding a saturated sodium chloride aqueous solution to form a 0.15 mol / L titanium trichloride solution; mixing an 85 wt % urea aqueous solution and anatase titanium dioxide at a solid-liquid ratio of 1:5, and performing wet grinding at a rotation speed of 500 rpm for 25 min. After the wet grinding is completed, the mixture is stirred at 40 °C for 2 hours according to the formula: n (urea): n (Ti 3+ )=10:1, add titanium trichloride solution, stir at 200rpm for 10min, spray granulate at a pressure of 1.5MPa and 110℃, and dry at 170℃ for 4h to obtain a mixed powder;

[0047] (2) placing the mixed powder in a gas grinder, turning on the gas jet device of the gas grinder, with a jet speed of 30 m / s and a gas temperature of 550° C., so that the mixed powder is continuously collided and ground for 35 minutes to obtain a highly effective antibacterial agent; the gas used in the gas jet device is a mixture of precursor copper acetylacetonate volatiles and argon gas at a volume ratio of 1:10;

[0048] (3) A high-efficiency antibacterial agent, fly ash, and a 35 wt% quaternary ammonium polyvinyl alcohol aqueous solution were mixed, a 12% mass fraction NaOH solution was added dropwise, the pH was adjusted to 12, and the mixture was stirred at 70°C and 400 r / min for 10 min to obtain a mixed gel, and the mixed gel was dried at 95°C until the water content was less than 5%, crushed, and passed through a 200 mesh sieve to obtain a masterbatch; the mass ratio of the high-efficiency antibacterial agent, fly ash, and quaternary ammonium polyvinyl alcohol was 16:8:70;

[0049] (4) Mix the masterbatch, polyethylene and silicone oil in a mass ratio of 35:75:8, extrude at 190°C to 220°C to obtain a mildew-proof and antibacterial plastic; the polyethylene is an ultra-high molecular weight polyethylene with a weight average molecular weight of 7 million and a 0.960 g / cm 3 High-density polyethylene at a mass ratio of 10:15.

[0050] Comparative Example 1

[0051] The difference between Comparative Example 1 and Example 1 is that there is no step (2), and step (1) is changed to: urea and anatase titanium dioxide are mixed in a mass ratio of 1:1, and calcined at 550° C. for 3 h to obtain a high-efficiency antibacterial agent. The remaining steps are the same as Example 1.

[0052] Comparative Example 2

[0053] The difference between Comparative Example 2 and Example 1 is that step (1) is different. Step (1) is changed to: urea and anatase titanium dioxide are mixed in a mass ratio of 1:1, and calcined at 550° C. for 3 h to obtain a mixed powder. The remaining steps are the same as Example 1.

[0054] Comparative Example 3

[0055] The difference between Comparative Example 3 and Example 1 is that step (1) is different, and step (1) is changed to: dissolving titanium trichloride in 3wt% hydrochloric acid to obtain a solution in which titanium trichloride accounts for 20% by volume, and then adding a saturated sodium chloride aqueous solution to form a 0.15mol / L titanium trichloride solution; according to n(urea): n(Ti 3+ )=10:1, titanium trichloride solution and urea aqueous solution with a mass concentration of 75% were added, stirred at 100rpm for 10min, spray granulated at a pressure of 0.5MPa and 100°C, and dried at 170°C for 1h to obtain a mixed powder; the remaining steps were the same as in Example 1.

[0056] Comparative Example 4

[0057] The difference between Comparative Example 4 and Example 1 is that there is no step (2), and step (1) is changed to: dissolving titanium trichloride in 3wt% hydrochloric acid to obtain a solution in which titanium trichloride accounts for 20% by volume, and then adding a saturated sodium chloride aqueous solution to form a 0.15 mol / L titanium trichloride solution; according to n(urea): n(Ti 3+ )=10:1, titanium trichloride solution and urea aqueous solution with a mass concentration of 75% were added, stirred at 100rpm for 10min, spray granulated at a pressure of 0.5MPa and 100°C, and dried at 170°C for 1h to obtain a mixed powder; the remaining steps were the same as in Example 1.

[0058] Comparative Example 5

[0059] The difference between Comparative Example 5 and Example 1 is that there is no step (1), and step (2) is changed to: C3N4 is placed in a gas grinder, and the gas injection device of the gas grinder is turned on, the injection speed is 20m / s, the gas temperature used by the gas injection device is 550°C, and the mixed powder is continuously collided and ground for 25min to obtain a high-efficiency antibacterial agent; the gas used in the gas injection device is a mixture of the precursor copper acetylacetonate volatiles and argon in a volume ratio of 1:10; the remaining steps are the same as Example 1.

[0060] Comparative Example 6

[0061] The difference between Comparative Example 6 and Example 1 is that steps (1) and (2) are omitted, and step (3) is changed to: titanium dioxide, C3N4, fly ash, and 20wt% quaternary ammonium polyvinyl alcohol aqueous solution are mixed, a 12% mass fraction NaOH solution is added dropwise, the pH is adjusted to 12, and the mixture is stirred at 70°C and 400r / min for 10min to obtain a mixed gel, the mixed gel is dried at 95°C to a water content of less than 5%, crushed, and passed through a 200-mesh sieve to obtain a masterbatch; the mass ratio of titanium dioxide, C3N4, fly ash, and quaternary ammonium polyvinyl alcohol is 8:2:3:40; and the remaining steps are the same as Example 1.

[0062] Comparative Example 7

[0063] The difference between Comparative Example 7 and Example 1 is that there is no step (3), and step (4) is changed to: a high-efficiency antibacterial agent, fly ash, quaternary ammonium polyvinyl alcohol, polyethylene, and silicone oil are extruded at 190° C. to 220° C. to obtain a mildew-proof and antibacterial plastic; the mass ratio of the high-efficiency antibacterial agent, fly ash, quaternary ammonium polyvinyl alcohol, polyethylene, and silicone oil is 10:3:40:100:12, and the polyethylene is an ultra-high molecular weight polyethylene with a weight average molecular weight of 5 million and a 0.941 g / cm 3 The high-density polyethylene is prepared in a mass ratio of 10:5; the remaining steps are the same as in Example 1.

[0064] Comparative Example 8

[0065] The difference between Comparative Example 8 and Example 1 is that silicone oil is not added, and the remaining steps are the same as Example 1.

[0066] Effect example

[0067] Table 1 below shows the performance analysis results of the plastics of Examples 1 to 5 of the present invention and Comparative Examples 1 to 8.

[0068] Table 1

[0069]

[0070]

[0071] The present invention uses carbon / nitrogen source precursor and different titanium sources as raw materials, and then calcined and modified to prepare a modified mixed crystal phase TiO2 / C3N4 high-efficiency antibacterial agent, so that the prepared plastic has strong antibacterial and mildew resistance, good durability, good biocompatibility, low toxicity, and is more environmentally friendly. The present invention uses fly ash, high-efficiency antibacterial agent and quaternized polyvinyl alcohol as master batches. In an alkaline environment, the dense protective film on the surface of the fly ash is destroyed, the activity of the fly ash is improved, and some surface particles are negatively charged, and electrostatically bonded with the cations of the quaternized polyvinyl alcohol to achieve compatibility between materials, and the master batch is extruded with ultra-high molecular weight polyethylene, high-density polyethylene, and silicone oil. The silicone oil has poor compatibility with the matrix and migrates to the surface of the material to form a hydrophobic layer on the surface of the composite film, which preliminarily reduces the adhesion of microorganisms on the plastic surface and improves the antibacterial property of the plastic.

[0072] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and scope of the equivalent elements of the claims be included in the invention. Any marking in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A method for preparing mildew-proof and antibacterial plastics, characterized in that: The method comprises the following preparation steps: (1) A urea aqueous solution with a mass concentration of 75 to 85% and anatase titanium dioxide are mixed at a solid-liquid ratio of 1:2 to 1:5 and wet-ground. After the wet-ground grinding is completed, the mixture is mixed according to n (urea): n (Ti 3+ )=1~10: 1~10 add titanium trichloride solution, stir at 100~200rpm for 10min, spray granulate at a pressure of 0.5~1.5MPa and 100~110℃, dry at 120~170℃ for 1~4h to obtain mixed powder; (2) The mixed powder is placed in a gas grinder, and the gas jet spray device of the gas grinder is turned on to make the mixed powder collide continuously and grind for 25 to 35 minutes to obtain a highly effective antibacterial agent; (3) mixing a high-efficiency antibacterial agent, fly ash, and a 20-35 wt% quaternary ammonium polyvinyl alcohol aqueous solution, adding a 12% NaOH solution by mass, adjusting the pH to 12, stirring at 70° C. and 400 r / min for 10 min to obtain a mixed gel, drying the mixed gel at 95° C. to a water content of less than 5%, crushing, and passing through a 200-mesh sieve to obtain a masterbatch; (4) Mix the masterbatch, polyethylene and silicone oil in a mass ratio of 20-35:50-75:6-8, and extrude at 190° C. to 220° C. to obtain a mildew-proof and antibacterial plastic.

2. The method for preparing a mildew-proof and antibacterial plastic according to claim 1, characterized in that: The rotation speed of the wet grinding in step (1) is 100 rpm-500 rpm, and the time of the wet grinding is 10 min-90 min.

3. The method for preparing a mildew-proof and antibacterial plastic according to claim 1, characterized in that: The titanium trichloride solution in step (1) is prepared by dissolving titanium trichloride in 3 wt % hydrochloric acid to obtain a solution in which titanium trichloride accounts for 20% by volume, and then adding a saturated sodium chloride aqueous solution to form a 0.15 mol / L titanium trichloride solution.

4. The method for preparing a mildew-proof and antibacterial plastic according to claim 1, characterized in that: The gas used by the gas jet spray device in step (2) is prepared by mixing the precursor copper acetylacetonate volatiles and argon gas in a volume ratio of 1:10; the injection speed of the gas jet spray device is 20-30 m / s, and the gas temperature used by the gas jet device is 400-550°C.

5. The method for preparing a mildew-proof and antibacterial plastic according to claim 1, characterized in that: In step (3), the quaternized polyvinyl alcohol has a quaternized substitution degree molar ratio of 49.8±3.5%.

6. The method for preparing a mildew-proof and antibacterial plastic according to claim 1, characterized in that: In step (3), the mass ratio of the high-efficiency antibacterial agent, fly ash and quaternized polyvinyl alcohol is 10-16:3-8:40-70.

7. The method for preparing a mildew-proof and antibacterial plastic according to claim 1, characterized in that: The polyethylene in step (4) is an ultra-high molecular weight polyethylene with a weight average molecular weight of 5 million to 7 million and a carbon content of 0.941 to 0.960 g / cm 3 The mass ratio of high-density polyethylene is 10-20:5-15.

8. A mildew-proof and antibacterial plastic, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 7.

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