Cationic quaternary phosphonium salt copolymer, its preparation method and application and antibacterial plastic

Abstract

The application relates to the field of antibacterial functional polymer materials, and discloses a cationic quaternary phosphonium salt copolymer, a preparation method and application thereof, and antibacterial plastic. The cationic quaternary phosphonium salt copolymer comprises structural unit A with a structure shown in formula I, structural unit B with a structure shown in formula II and structural unit C with a structure shown in formula III; the cationic quaternary phosphonium salt copolymer comprises a main structural unit provided by an isoolefin and a cationic quaternary phosphonium salt functional structural unit provided by an aryl olefin, and a macromolecular skeleton is formed, and an olefinate functional group is introduced into a side group; the cationic quaternary phosphonium salt copolymer can be grafted onto plastic in the form of a chemical bond to prepare antibacterial plastic, the antibacterial plastic not only has antibacterial performance, but also can improve compatibility and improve thermal stability.

Description

Technical Field

[0001] This invention relates to the field of antibacterial functional polymer materials, specifically to a cationic quaternary phosphonium salt copolymer, its preparation method and application, and antibacterial plastics. Background Technology

[0002] Antimicrobial plastics represent a new direction in the development of functional materials. They involve adding antimicrobial components to plastics to create plastics with bactericidal and bacteriostatic functions. During contact with bacteria, these components kill or inhibit bacterial growth on the plastic. This type of plastic not only maintains its own cleanliness but also reduces cross-contamination from using plastic products.

[0003] In addition to basic antibacterial properties, antibacterial plastics must also possess high efficiency and broad-spectrum antibacterial activity, and be toxicologically free of side effects, odorless, and environmentally friendly. Furthermore, antibacterial agents are reactive substances; they should not react with other substances in the matrix resin, and should have good compatibility with the matrix resin, remaining unaffected by natural conditions such as light, heat, and pH. The processing conditions for antibacterial plastics are very specific, requiring the antibacterial agents used in the plastic to have excellent heat resistance.

[0004] Commonly used antibacterial agents include inorganic, natural, and organic antibacterial agents. Inorganic antibacterial agents have long suffered from drawbacks such as easy discoloration, high cost, and easy leakage. Natural antibacterial agents are complex to process and have poor heat resistance. Small-molecule organic antibacterial agents are release or leaching type, which can pollute the environment and have poor heat resistance; in particular, their decomposition products are toxic, limiting their application areas. Polymer antibacterial agents are characterized by non-migration, non-release, safety, low toxicity, stable, efficient, and long-lasting antibacterial properties, making antibacterial plastics safer, more environmentally friendly, greener, and lower cost. With the gradual maturation of quaternary ammonium salt antibacterial agents and their widespread application in various industries, some harmful microorganisms have developed resistance, significantly weakening their antibacterial effect. The structure of quaternary phosphonium salts is similar to that of quaternary ammonium salts. Compared to quaternary ammonium salts, phosphonium (P) and nitrogen (N) belong to the same main group, but phosphonium has a larger radius, resulting in stronger polarization. It loses electrons and becomes positively charged, making it easier to attract negatively charged bacteria through electrostatic interactions. Because phosphonium has a weaker electronegativity than nitrogen, the structure of quaternary phosphonium salt molecules is more stable than that of quaternary ammonium salt molecules. They do not readily react with common oxidizing and reducing agents, as well as acids and bases, and possess advantages such as low toxicity, broad-spectrum activity, and good thermal stability.

[0005] There are two main methods for introducing antibacterial agents into antibacterial plastics: melt blending and chemical grafting. Chemical grafting, because the antibacterial functional groups are grafted onto the resin in the form of chemical bonds, overcomes the problems of antibacterial agents easily leaching and causing environmental pollution or harm to humans or other organisms. At the same time, grafting also overcomes the shortcomings of ordinary organic antibacterial agents, such as poor heat resistance, poor compatibility with the matrix, poor resistance to immersion and washing, and poor safety of exudates. It has significant advantages in terms of high efficiency, broad spectrum, safety, non-toxicity, long-lasting antibacterial effect, excellent thermal stability, good compatibility with resins, and excellent processability. Summary of the Invention

[0006] The purpose of this invention is to overcome the problem of poor stability of antibacterial plastics caused by the easy loss of antibacterial agents in existing antibacterial plastics. This invention provides a cationic quaternary phosphonium salt copolymer, its preparation method and application, and antibacterial plastics. The cationic quaternary phosphonium salt copolymer comprises a macromolecular skeleton composed of a main structural unit provided by isoolefins and cationic quaternary phosphonium salt functional structural units provided by arylolefins. Simultaneously, acrylate functional groups are introduced into the side groups of the polymer, enabling the cationic quaternary phosphonium salt copolymer to be used as an antibacterial agent in the preparation of antibacterial plastics with stable, long-lasting, safe, and low-toxicity antibacterial properties, and to effectively inhibit and kill bacteria, fungi, viruses, etc.

[0007] To achieve the above objectives, the first aspect of the present invention provides a cationic quaternary phosphonium salt copolymer, the copolymer comprising structural unit A of Formula I, structural unit B of Formula II, and structural unit C of Formula III;

[0008]

[0009] In this configuration, R1 and R2 are each independently C1-C4 alkyl groups; R3 is a C1-C4 alkylene group; R4, R5 and R6 are each independently C1-C4 alkyl or aryl groups; X is a halogen; and R7 is H, a C1-C4 alkyl or aryl group.

[0010] A second aspect of the present invention provides a method for preparing a cationic quaternary phosphonium salt copolymer, the method comprising:

[0011] S1. In the presence of a solvent and an initiator, an isoolefin and an aryl olefin are subjected to a cationic polymerization reaction, and a terminator is added to obtain a solution containing an isoolefin-aryl olefin copolymer.

[0012] S2. A halogenating agent is added to the solution containing the isoolefin-arylolefin copolymer to carry out a halogenation reaction, thereby obtaining a halogenated isoolefin-arylolefin copolymer solution.

[0013] S3. Add activator A to the solution of haloisoolefin-arylolefin copolymer to carry out an active functionalization reaction, and then add organophosphorus compound to carry out an ionization reaction to obtain cationic quaternary phosphonium salt copolymer;

[0014] The activator A is an olefinic acid compound with the structure shown in Formula IV:

[0015] R7' is H, C1-C4 alkyl or aryl.

[0016] A third aspect of the present invention provides a cationic quaternary phosphonium salt copolymer prepared by the method described in the second aspect above.

[0017] The fourth aspect of the present invention provides the use of the cationic quaternary phosphonium salt copolymer described in the first or third aspect above as an antibacterial agent.

[0018] The fifth aspect of the present invention provides a cationic quaternary phosphonium salt copolymer as described in the first or third aspect above for inhibiting and killing at least one of bacteria, fungi and viruses.

[0019] A sixth aspect of the present invention provides an antibacterial plastic comprising the cationic quaternary phosphonium salt copolymer and plastic described in the first or third aspect above;

[0020] The cationic quaternary phosphonium salt copolymer is chemically covalently grafted into the plastic.

[0021] Through the above technical solutions, the cationic quaternary phosphonium salt copolymer, its preparation method, its application, and antibacterial plastics provided by the present invention achieve the following beneficial effects:

[0022] The cationic quaternary phosphonium salt copolymer provided by this invention comprises a macromolecular backbone composed of a host structural unit provided by an isoolefin and a cationic quaternary phosphonium salt functional structural unit provided by an aryl olefin. At the same time, acrylate functional groups are introduced into the side groups of the copolymer, so that the cationic quaternary phosphonium salt copolymer has highly reactive double bonds, which can be used as an antibacterial agent and grafted onto plastics in the form of chemical bonds to prepare antibacterial plastics. This not only gives the plastics antibacterial properties, but also improves the compatibility of the plastics and further enhances the thermal stability of the antibacterial plastics. Detailed Implementation

[0023] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0024] The first aspect of the present invention provides a cationic quaternary phosphonium salt copolymer, the copolymer comprising structural unit A of Formula I, structural unit B of Formula II, and structural unit C of Formula III;

[0025]

[0026] In this configuration, R1 and R2 are each independently C1-C4 alkyl groups; R3 is a C1-C4 alkylene group; R4, R5 and R6 are each independently C1-C4 alkyl or aryl groups; X is a halogen; and R7 is H, a C1-C4 alkyl or aryl group.

[0027] In this invention, R1 and R2 are each independently C1-C4 alkyl groups, including methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, and tert-butyl, etc.; R3 is a C1-C4 alkylene group, including methylene, ethylene, propylene, isopropylene, butylene, and isobutylene, etc.; R4, R5, and R6 are each independently C1-C4 alkyl or aryl groups, including methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, and tert-butylphenyl, etc.; X is a halogen, including chlorine, bromine, iodine, etc.; R7 is H, a C1-C4 alkyl or aryl group, including but not limited to H, methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, and phenyl, etc.

[0028] In this invention, the cationic quaternary phosphonium salt copolymer comprises a macromolecular skeleton composed of a main structural unit provided by an isoolefin and a cationic quaternary phosphonium salt functional structural unit provided by an aryl olefin. At the same time, acrylate functional groups are introduced into the side groups of the polymer, so that the cationic quaternary phosphonium salt copolymer has highly reactive double bonds and can be used as an antibacterial agent with long-lasting and stable antibacterial effect.

[0029] Furthermore, R1 and R2 are each independently a C1-C3 alkyl group, R3 is a C1-C3 alkylene group, and R4, R5, and R6 are each independently a C1-C3 alkyl group or a C6-C3 alkyl group. 10 The aryl group, where X is Cl or Br, and R7 is a C1-C3 alkyl group or a C6-C4 alkyl group. 10 Aryl groups.

[0030] In a preferred embodiment of the present invention, R1 and R2 are each independently methyl; R3 is methylene; R4, R5 and R6 are each independently phenyl; X is Br; and R7 is phenyl.

[0031] According to the present invention, preferably, based on the total molar amount of the cationic quaternary phosphonium salt copolymer, the content of structural unit A is 70-95 mol%, the content of structural unit B is 4-25 mol%, and the content of structural unit C is 1-8 mol%.

[0032] In this invention, when the content of each structural unit in the copolymer meets the above-mentioned range, the copolymer has good compatibility with other polymers containing unsaturated double bonds due to the high content of benzene rings and reactive unsaturated double bonds.

[0033] Furthermore, based on the total molar amount of the cationic quaternary phosphonium salt copolymer, the content of structural unit A is 75-92 mol%, the content of structural unit B is 6-18 mol%, and the content of structural unit C is 2-6 mol%.

[0034] In this invention, the contents of structural units A, B and C in the cationic quaternary phosphonium salt copolymer were measured using an AVANCE NEO 600M nuclear magnetic resonance spectrometer manufactured by Bruker GmbH, Switzerland.

[0035] In this invention, the cationic quaternary phosphonium salt copolymer further includes the structures shown in formulas (1), (2), and (3):

[0036]

[0037] R3' is a C1-C4 alkyl group; R3 is a C1-C4 alkylene group; R4, R5 and R6 are each independently a C1-C4 alkyl or aryl group; X is a halogen.

[0038] In this invention, based on the total molar amount of the cationic quaternary phosphonium salt copolymer, the total content of the structures shown in formulas (1), (2), and (3) is 0-3 mol%, preferably 0.5-2.5 mol%.

[0039] In this invention, the total content of the structures represented by formulas (1), (2) and (3) in the cationic quaternary phosphonium salt copolymer was measured using an AVANCE NEO 600M nuclear magnetic resonance spectrometer manufactured by Bruker GmbH, Switzerland.

[0040] According to the present invention, preferably, the weight-average molecular weight of the cationic quaternary phosphonium salt copolymer is 1 × 10⁻⁶. 4 -1×10 5 g / mol, with a molecular weight distribution of 1.5-3.5.

[0041] In this invention, when the weight-average molecular weight and molecular weight distribution of the cationic quaternary phosphonium salt copolymer meet the above-mentioned ranges, it is beneficial to improve the thermal stability of the copolymer.

[0042] Furthermore, the weight-average molecular weight of the cationic quaternary phosphonium salt copolymer is 2 × 10⁻⁶. 4 -5×10 4 g / mol, with a molecular weight distribution of 2-3.

[0043] In this invention, the weight-average molecular weight and molecular weight distribution of the cationic quaternary phosphonium salt copolymer were determined using an LC-20A liquid chromatography-gel permeation chromatograph (GPC) manufactured by Shimadzu Corporation of Japan.

[0044] According to the present invention, preferably, the 5wt% thermogravimetric temperature of the cationic quaternary phosphonium salt copolymer is ≥210°C.

[0045] In this invention, the cationic quaternary phosphonium salt copolymer has a high thermal decomposition temperature and a high 5wt% thermal weight loss temperature, which makes the polymer meet the requirements of the thermal processing of polymer materials and can be used as an antibacterial agent directly in combination with plastics to prepare antibacterial plastics.

[0046] Furthermore, the 5wt% thermogravimetric temperature of the cationic quaternary phosphonium salt copolymer is ≥230°C.

[0047] A second aspect of the present invention provides a method for preparing a cationic quaternary phosphonium salt copolymer, the method comprising:

[0048] S1. In the presence of a solvent and an initiator, an isoolefin and an aryl olefin are subjected to a cationic polymerization reaction, and a terminator is added to obtain a solution containing an isoolefin-aryl olefin copolymer.

[0049] S2. A halogenating agent is added to the solution containing the isoolefin-arylolefin copolymer to carry out a halogenation reaction, thereby obtaining a halogenated isoolefin-arylolefin copolymer solution.

[0050] S3. Add activator A to the solution of haloisoolefin-arylolefin copolymer to carry out an active functionalization reaction, and then add organophosphorus compound to carry out an ionization reaction to obtain cationic quaternary phosphonium salt copolymer;

[0051] The activator A is an olefinic acid compound with the structure shown in Formula IV:

[0052] R7' is H, C1-C4 alkyl or aryl.

[0053] In this invention, isoolefins and arylolefins are cationicly polymerized in the presence of a solvent and an initiator, enabling control over the weight-average molecular weight of the copolymer. Furthermore, after halogenation with a halogenating agent and reactive functionalization, highly reactive acrylate functional groups are introduced into the molecular chain of the copolymer, and more cationic quaternary phosphonium salt functional groups are introduced through ionization. The preparation method is simple, and the resulting copolymer is an antibacterial agent containing cationic quaternary phosphonium salt functional groups and highly reactive acrylate functional groups. This not only gives plastics antibacterial properties but also improves the compatibility of plastics and further enhances the thermal stability of antibacterial plastics.

[0054] Furthermore, R7' is a C1-C3 alkyl group or a C6-C3 alkyl group. 10 Aryl groups.

[0055] According to the present invention, preferably, the isoolefin has the structure shown in Formula V, and the arylolefin has the structure shown in Formula VI;

[0056]

[0057] R1', R2' and R3' are each independently a C1-C4 alkyl group, preferably a C1-C3 alkyl group.

[0058] In this invention, in step (1), the solvent includes a haloalkane and at least one alkane.

[0059] In this invention, the volume ratio of the haloalkane to the alkane is 1:1-4.

[0060] In this invention, when the volume ratio of the haloalkane to the alkane meets the above-mentioned range, the reaction rate of cationic polymerization can be increased, the amount of activator in the initiator system for cationic polymerization can be reduced, and the side reactions during the halogenation reaction of the obtained isoolefin-arylolefin copolymer solution can be significantly reduced, thereby improving the purity of the final cationic quaternary phosphonium salt copolymer.

[0061] Furthermore, the volume ratio of the haloalkane to the alkane is 1:1.5-3.

[0062] In this invention, the haloalkane is selected from dichloromethane and / or trichloromethane.

[0063] In a preferred embodiment of the present invention, the haloalkane is dichloromethane.

[0064] In this invention, the alkanes include aliphatic alkanes and alicyclic alkanes. The aliphatic alkanes are preferably C3-C64. 10 The aliphatic alkanes, more preferably C5-C8 aliphatic alkanes; the alicyclic alkanes are preferably C3-C8. 10 The alkane is an alicyclic alkane, more preferably a C5-C8 alicyclic alkane. The alkane may be at least one selected from n-pentane, isopentane, 2-methylpentane, 3-methylpentane, n-hexane, cyclohexane, n-heptane, isoheptane, n-octane, and isooctane, preferably n-hexane.

[0065] In this invention, there is no particular limitation on the amount of solvent used, and it can be a conventional choice in the art. Preferably, the amount of solvent used is such that the total concentration of isoolefins and arylolefins is 10-35 wt%, for example, it can be any two values ​​within the range of 10 wt%, 12 wt%, 15 wt%, 18 wt%, 20 wt%, 23 wt%, 25 wt%, 30 wt%, 35 wt%, or more, and more preferably 15-25 wt%.

[0066] According to the present invention, preferably, based on the total amount of the isoolefin and arylolefin, the mole fraction of the arylolefin is 5-30 mol%, for example, it can be any two values ​​within the range of 5 mol%, 10 mol%, 15 mol%, 18 mol%, 20 mol%, 22 mol%, 24 mol%, 25 mol%, 28 mol%, 30 mol%, or more, and more preferably 8-25 mol%.

[0067] In this invention, the preferred isoolefin includes, but is not limited to, at least one of isobutylene, 2-methyl-1-butene, 2-methyl-1-pentene, and 2-methyl-1-hexene; more preferably, the isoolefin is isobutylene.

[0068] In this invention, the aryl olefin preferably includes, but is not limited to, at least one of p-methylstyrene, m-methylstyrene, p-ethylstyrene, and p-tert-butylstyrene; more preferably, the aryl olefin is p-methylstyrene.

[0069] In this invention, there are no particular limitations on the initiator used for cationic polymerization. Conventional cationic polymerization initiators in the art can be used. For example, the initiator includes a compound that can donate protons, a Lewis acid, and an activator. This initiator has high initiation efficiency, enabling the monomer conversion rate to reach 100%, and can then be directly used for halogenation reactions.

[0070] According to the present invention, preferably, the initiator comprises a proton-donating compound, a Lewis acid, and an activator B.

[0071] According to the present invention, preferably, the molar ratio of the proton-donating compound, the Lewis acid, and the activator B in the initiator is 0.02-0.5:1:0.005-0.2, more preferably 0.05-0.3:1:0.01-0.12.

[0072] In this invention, the proton-donating compound can be any of the proton-donating compounds commonly used in the field of cationic polymerization. Generally, the proton-donating compound can be H2O and / or a protic acid, such as H2O, HCl, HF, HBr, H2SO4, H2CO3, H3PO4, and HNO3.

[0073] In this invention, the Lewis acid can be at least one of trimethylaluminum and triethylaluminum, dichloromethylaluminum, dichloroethylaluminum, dichloro-n-propylaluminum, dichloroisopropylaluminum, dichloro-n-butylaluminum, dichloroisobutylaluminum, dimethylaluminum chloride, diethylaluminum chloride, di-n-propylaluminum chloride, diisopropylaluminum chloride, di-n-butylaluminum chloride, and diisobutylaluminum chloride.

[0074] In this invention, the activator B can be at least one of tetrachlorobenzoquinone, tetrahydrobenzoquinone, tetracyanobenzoquinone, and dichlorodicyanobenzoquinone.

[0075] In a preferred embodiment of the present invention, the initiator is a hydrogen chloride / dichloroethylaluminum / tetrachlorobenzoquinone (HCl / EADC / TCBQ) system.

[0076] In this invention, the initiator exists in solution form.

[0077] In this invention, there is no particular limitation on the concentration of the initiator solution. For example, the concentration of the hydrogen chloride solution can be 0.018 mol / L, the concentration of the dichloroethylaluminum solution can be 0.09 mol / L, and the concentration of the tetrachlorobenzoquinone solution can be 0.009 mol / L. In practical applications, the solutions of the above concentrations can be directly mixed evenly before use.

[0078] In this invention, it is preferable to use the initiator solution after aging. The aging conditions can be conventional conditions in the art, such as aging at -60°C to -20°C for 0.5-2 hours.

[0079] In this invention, there is no particular limitation on the amount of the initiator. It can be appropriately selected according to the specific polymerization conditions to initiate the polymerization of all isoolefins and arylolefins.

[0080] According to the present invention, preferably, the polymerization temperature of the cationic polymerization is -80°C to 0°C, more preferably -60°C to -20°C.

[0081] According to the present invention, preferably, the polymerization time of the cationic polymerization is 10-90 min, more preferably 20-60 min.

[0082] In this invention, there is no particular limitation on the type of terminator mentioned in step (1), and it can be a conventional type of terminator in the art, such as triethylene glycol.

[0083] In this invention, there is no particular limitation on the amount of terminating agent used, as long as it can terminate the polymerization reaction.

[0084] In one specific embodiment of the present invention, the method further includes washing the terminated product with water.

[0085] In this invention, by washing the terminated product with water, the complex formed by the termination reaction dissolved in water can be removed, thereby reducing the aluminum ion content of the copolymer.

[0086] In this invention, the water washing process includes: heating the terminated product to room temperature, adding deionized water and stirring to mix evenly, allowing it to stand and separate into layers, and removing the water from the lower layer.

[0087] Unless otherwise specified, room temperature in this invention refers to 25°C.

[0088] In this invention, the volume ratio of water to the terminated product is 0.5-3:1, preferably 1-2:1.

[0089] In this invention, the settling time is 0.5-4 hours, preferably 1-3 hours.

[0090] According to the present invention, preferably, the halogenating agent in step (2) is a halogen element, preferably bromine and / or chlorine, and more preferably bromine.

[0091] In this invention, in step (2), the solution of the isoolefin and aryl olefin copolymer is subjected to a halogenation reaction, and a halogen substitution reaction is carried out with the structural units from the aryl olefin in the copolymer macromolecular chain.

[0092] In this invention, the halogenation reaction can be carried out under conventional conditions, as long as it enables the isoolefin-arylolefin copolymer to undergo halogenation. For example, the halogenation reaction is carried out in the presence of at least one free radical initiator, preferably, the halogenation reaction is initiated under visible light irradiation.

[0093] In this invention, when the halogenation reaction is carried out under visible light irradiation, the irradiation conditions are such that they can initiate the halogenation reaction of the isoolefin-arylolefin copolymer.

[0094] According to the present invention, preferably, the wavelength of the visible light is 590-630nm and the light intensity is 80-200mW.

[0095] According to the present invention, preferably, the visible light emission mode is pulsed emission.

[0096] In this invention, pulsed light emission refers to the light source emitting light waves and stopping light waves with equal time differences and alternating. Specifically, the pulse duration of the pulsed light emission is preferably 5-40s, and more preferably 10-30s.

[0097] In this invention, there is no special limitation on the temperature of the halogenation reaction, and it can be selected conventionally; the time of the halogenation reaction can be selected according to the reaction temperature and the expected degree of halogenation reaction.

[0098] In this invention, the amount of halogen atoms introduced into the molecular chain of the isoolefin-arylolefin copolymer can be selected according to the intended use of the final polymer. According to a preferred embodiment of the invention, the molar ratio of the halogenating agent to the isoolefin-arylolefin copolymer, based on the structural units provided by the aryl olefin, is 1-1.2:1, preferably 1-1.1:1.

[0099] In this invention, preferably, a halogenating agent, such as a halogen, is mixed with an organic solvent to obtain a halogen solution, and the halogen solution is added dropwise to the copolymer solution to carry out a halogenation reaction, so as to achieve selective control of the halogenation reaction.

[0100] In this invention, the organic solvent is a haloalkane, such as dichloromethane.

[0101] In one specific embodiment of the present invention, a halogen solution is slowly added dropwise to a copolymer solution, and a photohalogenation reaction is carried out under visible light irradiation by a pulsed LED light source at a wavelength of 590 nm-630 nm to obtain a halogenated copolymer solution. The structural units derived from aryl olefins in the copolymer macromolecular chain undergo halogen substitution reactions.

[0102] In this invention, the halogen solution is added at a rate of 50-100 drops / min.

[0103] In this invention, the dropping rate of the halogen solution is controlled so that the halogenation reaction time is 30-150 min, preferably 60-120 min.

[0104] In this invention, to neutralize the hydrogen halides generated during the halogenation reaction, a certain amount of alkaline compounds, such as sodium carbonate, sodium bicarbonate, calcium carbonate, magnesium carbonate, calcium oxide, magnesium oxide, etc., can be added to the copolymer solution, preferably hydrocarbonated. The halogenated copolymer solution is then centrifuged or filtered to remove the solid halide compounds.

[0105] In this invention, there are no particular limitations on the centrifugation or filtration equipment; any centrifugation or filtration equipment conventionally used by those skilled in the art can be selected. There are also no particular limitations on the centrifugation or filtration conditions; any conditions conventionally used by those skilled in the art can be applied.

[0106] According to a preferred embodiment of the present invention, a centrifuge is used to remove solid halide salts.

[0107] In this invention, the activator A in step (3) is an olefinic acid compound. Preferably, the olefinic acid compound is a monoolefinic acid, preferably at least one of acrylic acid, 2-butenoic acid, 2-pentenoic acid, 2-hexenoic acid, 2-heptenoic acid, 4-methyl-2-hexenoic acid, 5-methyl-2-hexenoic acid and 3-phenyl-2-acrylic acid, and more preferably 3-phenyl-2-acrylic acid.

[0108] According to the present invention, preferably, the molar ratio of the activator A to the halogenator is 0.05-0.5:1.

[0109] In this invention, when the molar ratio of the activator A to the halogenator meets the above-mentioned range, it can fully react with the benzyl halide on the halogenated isoolefin-aryl olefin copolymer, so that the activator A is completely converted into a reactive acrylate functional group.

[0110] Furthermore, the molar ratio of the activator A to the halogenator is 0.1-0.3:1.

[0111] According to the present invention, preferably, the conditions for the active functionalization reaction include: a reaction temperature of 60-100°C and a reaction time of 1-5 hours.

[0112] In this invention, when the conditions of the active functionalization reaction meet the above-mentioned range, it can be ensured that the activator A reacts sufficiently with the benzyl halide on the halogenated isoolefin-aryl olefin copolymer.

[0113] Furthermore, the conditions for the active functionalization reaction include: a reaction temperature of 70-90℃ and a reaction time of 2-4h.

[0114] According to the present invention, preferably, the organophosphorus compound has the structure shown in Formula VII:

[0115] R4', R5', and R6' are each independently a C1-C4 alkyl or aryl group, preferably each of R4', R5', and R6' is independently a C1-C3 alkyl or C6-C4 alkyl group. 10 Aryl groups.

[0116] In this invention, the organophosphorus compound is preferably a tertiary phosphine compound, preferably selected from at least one of trimethylphosphine, triethylphosphine, tripropylphosphine, tributylphosphine and triphenylphosphine, and more preferably triphenylphosphine.

[0117] According to the present invention, preferably, the molar ratio of the organophosphorus compound to the halogenating agent is 0.5-0.95:1.

[0118] In this invention, when the molar ratio of the organophosphorus compound to the halogenating agent meets the above-mentioned range, the organophosphorus compound can be fully introduced into the halogenated isoolefin-aryl olefin copolymer through an ionization reaction, so that the obtained cationic quaternary phosphonium salt copolymer has a controllable quaternary phosphonium salt group content.

[0119] Furthermore, the molar ratio of the organophosphorus compound to the halogenating agent is 0.7-0.9:1.

[0120] According to the present invention, preferably, the conditions for the ionization reaction include: a reaction temperature of 70-120°C, a reaction time of 4-12 h, and a reaction pressure of 0.35-1 MPa.

[0121] In this invention, when the conditions of the ionization reaction meet the above-mentioned range, the ionization reaction can have a high reaction rate, shorten the ionization reaction time, and improve the reaction efficiency of the ionization reaction.

[0122] Furthermore, the conditions for the ionization reaction include: a reaction temperature of 80-100℃, a reaction time of 6-10h, and a reaction pressure of 0.4-0.8MPa.

[0123] In one specific embodiment of the present invention, the method further includes, after the ionization reaction is completed, placing the slurry material into a filter to separate the solvent, the filtered copolymer being in the form of fine particles, pouring it into a washing vessel containing anhydrous ethanol for stirring and washing, and then separating it again through a filter to obtain the cationic quaternary phosphonium salt copolymer.

[0124] A third aspect of the present invention provides a cationic quaternary phosphonium salt copolymer prepared by the method described in the second aspect above.

[0125] The fourth aspect of the present invention provides the use of the cationic quaternary phosphonium salt copolymer described in the first or third aspect above as an antibacterial agent.

[0126] The fifth aspect of the present invention provides a cationic quaternary phosphonium salt copolymer described in the first or third aspect above for inhibiting and killing at least one of bacteria, fungi and viruses.

[0127] A sixth aspect of the present invention provides an antibacterial plastic comprising the cationic quaternary phosphonium salt copolymer and plastic described in the first or third aspect above.

[0128] According to the present invention, preferably, the cationic quaternary phosphonium salt copolymer is chemically covalently grafted into the plastic.

[0129] In this invention, the cationic quaternary phosphonium salt copolymer contains cationic quaternary phosphonium salt functional structural units and acrylate functional groups introduced into the side groups, which can provide reactive double bonds that can be chemically covalently grafted into plastics to improve the antibacterial properties of plastics and enhance their compatibility.

[0130] According to the present invention, preferably, the cationic quaternary phosphonium salt copolymer is 2-8 parts, more preferably 4-6 parts, relative to 100 parts of plastic.

[0131] According to the present invention, preferably, the plastic is selected from at least one of PE plastic, PP plastic and PVC plastic.

[0132] In this invention, the cationic quaternary phosphonium salt copolymer comprises a macromolecular skeleton composed of a host structural unit provided by an isoolefin and a cationic quaternary phosphonium salt functional structural unit provided by an aryl olefin. Simultaneously, acrylate functional groups are introduced into the side groups of the copolymer, giving the cationic quaternary phosphonium salt copolymer highly reactive double bonds. It can be used as an antibacterial agent and grafted onto plastics in the form of chemical bonds to prepare antibacterial plastics. This not only gives the plastics antibacterial properties but also improves the compatibility of the plastics and further enhances the thermal stability of the antibacterial plastics.

[0133] According to the present invention, preferably, the antibacterial plastic has a thermal weight loss temperature of ≥300°C for 5 wt% of its components.

[0134] Furthermore, the antibacterial plastic has a thermal weight loss temperature of ≥320°C at 5 wt%.

[0135] The present invention will be described in detail below through embodiments.

[0136] In the following examples, the content of each structural unit in the isoolefin-arylolefin copolymer and the cationic quaternary phosphonium salt copolymer was measured using an AVANCE NEO 600M nuclear magnetic resonance spectrometer manufactured by Bruker, Switzerland.

[0137] Determination of weight-average molecular weight and molecular weight distribution of copolymers: using an LC-20A liquid gel permeation chromatograph (GPC) manufactured by Shimadzu Corporation, Japan.

[0138] Method for determining polymerization conversion rate: the ratio of the mass of the copolymer obtained after polymerization to the mass of the added monomer.

[0139] Halogen content of halogenated isoolefin-aryl olefin copolymers: determined using a ZSXPrimuslV X-ray fluorescence spectrometer manufactured by Rigaku Corporation, Japan.

[0140] Thermogravimetric analysis of samples: The METTLER TGA / DSC1 instrument was used, with a test temperature range of 25-600℃, a heating rate of 10℃ / min, and a nitrogen atmosphere of 50mL / min.

[0141] Example 1

[0142] (1) In a 10L polymerization reactor equipped with a stirrer, a jacket, and an internal cooling pipe, 1.6L of dichloromethane, 2.4L of n-hexane, 0.7kg of isobutylene (IB), and 0.3kg of p-methylstyrene (p-MeSt) were added sequentially (the molar ratio of IB to p-MeSt was 5:1). The mixture was stirred and stirred until homogeneous. The temperature of the monomer solution was lowered to -40℃ using the coolant in the jacket and internal cooling pipe. 120mL of aged HCl / EADC / TCBQ initiator solution (the molar ratio of HCl / EADC / TCBQ was 0.2:1:0.1) was slowly added dropwise. The polymerization reaction temperature was controlled at -40±2℃ using the coolant in the jacket and internal cooling pipe. After 40min of polymerization, 45mL of terminator solution (a 3% triethylene glycol solution in dichloromethane) was added to terminate the reaction. The polymerization conversion rate, weight-average molecular weight, molecular weight distribution, and p-methylstyrene content of the prepared isoolefin-aryl olefin copolymers were measured by sampling. The results are listed in Table 2.

[0143] (2) Heat the reaction solution to room temperature, add 6L of deionized water (the volume ratio of water to the product in step (1) is approximately 1:1), stir and mix for 10 min, then let it stand for 2 hours to separate into layers, and release the water from the lower layer. Start stirring and add 240g of sodium bicarbonate. Take 143mL of liquid bromine and add it to a constant pressure dropping funnel containing 100mL of dichloromethane (the molar ratio of liquid bromine to p-methylstyrene in the copolymer is 1.1:1). Use a 590nm light source for the bromination reaction, with a light source intensity of 100mW and a pulse time of 20s. Turn on the light source to carry out the bromination reaction, and add the liquid bromine solution at a rate of 60 drops / min. After the liquid bromine solution has been added, continue the reaction for 10 minutes until the red color of the polymer solution basically disappears. Turn off the light source and stop the reaction. The total bromination reaction time is 90min. The bromine content in the bromine copolymer is determined, and the results are shown in Table 2.

[0144] (3) The insoluble precipitate in the brominated polymer solution was separated by centrifugation. The resulting clear liquid was transferred to a 10L jacketed pressure-resistant stirred tank, and stirring was started. 83g of 3-phenyl-2-acrylic acid (the molar ratio of 3-phenyl-2-acrylic acid to liquid bromine was 0.2:1) was added, and the reaction was carried out under reflux at a reaction temperature of 80℃ and a reaction pressure of 0.6MPa for 4 hours. Then, 660g of triphenylphosphine (the molar ratio of triphenylphosphine to liquid bromine was 0.9:1) was added, the temperature was raised to 100℃, the pressure was raised to 0.8MPa, and the reflux reaction was continued for 8 hours to obtain a slurry-like material. After the reaction was completed, the material was cooled to room temperature, and the granular polymer was separated by filtration. Then, it was soaked and washed with anhydrous ethanol, filtered again, and the obtained solid particles were dried in a vacuum oven at 40℃ for 6 hours to obtain a cationic quaternary phosphonium salt copolymer.

[0145] The content of each structural unit in the copolymer and the 5wt% thermogravimetric temperature were measured and the results are listed in Table 2.

[0146] Examples 2-6

[0147] The cationic quaternary phosphonium salt copolymer was prepared according to the method of Example 1, except that the amount of materials used in each step and the specific process conditions were different from those in Example 1, as shown in Table 1. The test results are shown in Table 2.

[0148] Example 7

[0149] The cationic quaternary phosphonium salt copolymer was prepared according to the method of Example 1, except that in step (3), the molar ratio of 3-phenyl-2-acrylic acid to liquid bromine was 0.5:1, and the molar ratio of triphenylphosphine to liquid bromine was 0.5:1, as shown in Table 1. The test results are shown in Table 2.

[0150] Example 8

[0151] The cationic quaternary phosphonium salt copolymer was prepared according to the method of Example 1, except that in step (3), the molar ratio of 3-phenyl-2-acrylic acid to liquid bromine was 0.05:1, and the molar ratio of triphenylphosphine to liquid bromine was 0.95:1, as shown in Table 1. The test results are shown in Table 2.

[0152] Example 9

[0153] The cationic quaternary phosphonium salt copolymer was prepared according to the method of Example 1, except that: in step (3), the amount of 3-phenyl-2-acrylic acid added was 366g (the molar ratio of 3-phenyl-2-acrylic acid to liquid bromine was 0.9:1); the amount of triphenylphosphine added was 144g (the molar ratio of triphenylphosphine to liquid bromine was 0.2:1), and the test results are shown in Table 2.

[0154] Comparative Example 1

[0155] The cationic quaternary phosphonium salt copolymer was prepared according to the method of Example 1, except that: in step (2), the amount of liquid bromine added was 104 mL (the molar ratio of liquid bromine to p-methylstyrene in the copolymer was 0.8:1), and 3-phenyl-2-acrylic acid was not added in step (3); the amount of triphenylphosphine added was 586 g (the molar ratio of triphenylphosphine to liquid bromine was 1.1:1), and the test results are shown in Table 2.

[0156] Table 1

[0157]

[0158]

[0159] Continued from Table 1

[0160]

[0161] Table 2

[0162]

[0163]

[0164] Note: Polymer a This refers to isoolefin-arylolefin polymers; halogenated polymers. b It refers to halogenated isoolefin-aryl olefin polymers.

[0165] Continued from Table 2

[0166]

[0167] As shown in Tables 1 and 2, the products prepared in Examples 1-6 have a higher content of structural unit B than those prepared in Examples 7 and 9, and their antibacterial properties are superior to those of the products prepared in Examples 7 and 9 at the same content. The products prepared in Examples 1-6 have a higher content of structural unit C than those prepared in Example 8, and their thermal stability (based on the temperature at which 5% weight loss occurs) is also superior. 5wt％ (As an evaluation criterion) slightly higher than the product prepared in Example 8. When the content of either structural unit B or structural unit C is too high or too low, the antibacterial properties and thermal stability of the final antibacterial plastic cannot be simultaneously achieved.

[0168] Comparison of the thermal stability of antibacterial plastics

[0169] Antibacterial plastic P1 was prepared by melt grafting the cationic quaternary phosphonium salt copolymer prepared in Example 1 with low-density polyethylene resin (LDPE). Antibacterial plastic P2 was prepared by blending the cationic quaternary phosphonium salt copolymer prepared in Comparative Example 1 with LDPE resin. The thermal stability of the two antibacterial plastics was then compared (based on the temperature at which 5% weight loss occurs).5wt％ (as a basis for evaluation).

[0170] Preparation process of antibacterial plastic P1: Using a Polylab OS PTW 16 / 40 twin-screw extruder, LDPE, cationic quaternary phosphonium salt copolymer, and initiator dicumyl peroxide were thoroughly mixed at a mass ratio of 94:6:0.15 and then fed into the twin-screw extruder. Melt grafting reaction was carried out at a temperature of 190℃ and a screw speed of 60rpm to obtain antibacterial plastic P1.

[0171] Preparation process of antibacterial plastic P2: Using a Polylab OS PTW 16 / 40 twin-screw extruder, LDPE and the cationic quaternary phosphonium salt copolymer prepared in Comparative Example 1 were first thoroughly mixed at a mass ratio of 8:2 and then fed into the twin-screw extruder. Melt extrusion granulation was carried out at a temperature of 190℃ and a screw speed of 60rpm to produce 20wt% antibacterial masterbatch. Then, the antibacterial masterbatch was mixed with LDPE and melt extruded and granulated again through the twin-screw extruder to produce 6wt% antibacterial plastic P2.

[0172] The cationic quaternary phosphonium salt copolymer prepared in Example 1 (denoted as A1), the cationic quaternary phosphonium salt copolymer prepared in Comparative Example 1 (denoted as A2), and the temperature at which antibacterial plastics P1 and P2 lose 5% of their thermal weight (T) 5wt％ See Table 3.

[0173] Table 3

[0174] product A1 A2 P1 P2 <![CDATA[T 5wt％ ,℃]]> 238 237 326 282

[0175] As can be seen from Table 3, under the same quaternary phosphonium salt content, the T of the quaternary phosphonium salt ionomer prepared in Example 1 is... 5wt％ T compared with the cationic quaternary phosphonium salt copolymer prepared in the comparative example 5wt％ While similar, the cationic quaternary phosphonium salt copolymer prepared in Example 1 contains reactive double bonds, which can be covalently grafted into the plastic to enhance its compatibility. The compatibility between the two is better than that between the cationic quaternary phosphonium salt copolymer prepared in the comparative example and the plastic, resulting in the antibacterial plastic prepared in Example 1 having significantly better thermal stability than the antibacterial plastic prepared in Comparative Example 1.

[0176] Test case

[0177] Antimicrobial plastics were prepared by melt grafting the cationic quaternary phosphonium salt copolymer prepared in Example 1 with LDPE. Escherichia coli and Staphylococcus aureus were used as Gram-negative and Gram-positive bacteria, respectively, to test the antimicrobial properties of the antimicrobial plastics.

[0178] Using a Polylab OS PTW 16 / 40 twin-screw extruder, LDPE, the quaternary phosphonium salt ionomer prepared in Example 1, and the initiator dicumyl peroxide were thoroughly mixed at mass ratios of 98:2:0.15, 96:4:0.15, 94:6:0.15, and 92:8:0.15, respectively, and then fed into the twin-screw extruder. Melt grafting reaction was carried out at a temperature of 190°C and a screw speed of 60 rpm to obtain antibacterial plastics with cationic quaternary phosphonium salt copolymers containing mass contents of 2 wt%, 4 wt%, 6 wt%, and 8 wt%, respectively.

[0179] The antibacterial plastic granules were molded into shape using a tablet press at 200℃ and 20MPa for 3 minutes. Then, they were cold-pressed at 15MPa for 10 minutes to obtain experimental sheets with a thickness of 1mm. After being placed for 24 hours, the sheets were cut into 20mm×20mm test samples.

[0180] (1) Place the sample slides in a cell culture plate and sterilize both sides with ultraviolet light for 30 min. Add 30 μL of bacterial suspension with a concentration of 1×10⁶ CFU / mL to the surface of each sample slide, and cover the bacterial suspension with a sterile round coverslip to spread the bacterial suspension evenly on the sample surface. Incubate the cell culture plate in a constant temperature incubator at 37℃, maintaining a relative humidity greater than 90%. After 24 h, add 2 mL of physiological saline to the culture plate with a pipette to rinse the sample surface, and sonicate the culture plate for 1 min to disperse the bacteria. Use a pipette to draw 100 μL of the rinsing solution and perform serial dilution with physiological saline. Select an appropriate dilution factor and spread it on nutrient agar plates. Incubate in a constant temperature incubator at 37℃ for 24 h. Select plates with colony counts of 30-300 for counting, calculate the number of viable bacteria on the sample surface, and calculate the antibacterial rate R. The results are shown in Table 4.

[0181] R = [(AB) / A] × 100%, where A is the number of viable bacteria on the surface of the plastic sample without antibacterial agent, and B is the number of viable bacteria on the surface of the antibacterial plastic sample.

[0182] Table 4

[0183]

[0184] (2) Take 5 antibacterial plastic samples, weigh them, put them into an Erlenmeyer flask, add deionized water at a ratio of 0.1 g / mL according to the requirements of GB / T16886.12-2005, place them in a constant temperature water bath shaker at 37℃ and shake at a speed of 150 r / min, and test the antibacterial performance of the samples after soaking for 15 days and 30 days respectively. The test method is the same as above. The results after soaking for 15 days are shown in Table 5, and the results after soaking for 30 days are shown in Table 6.

[0185] Table 5

[0186]

[0187] Table 6

[0188]

[0189]

[0190] As can be seen from the results in Tables 4 to 6, the antibacterial plastic prepared by using the cationic quaternary phosphonium salt copolymer prepared in Example 1 of the present invention in combination with LDPE resin has excellent antibacterial properties. Furthermore, when the amount of cationic quaternary phosphonium salt copolymer added reaches more than 4 parts, it shows more efficient bactericidal and bacteriostatic properties. Even after soaking in water for 15-30 days, the bactericidal and bacteriostatic properties are still good, and the antibacterial effect is excellent.

[0191] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A cationic quaternary phosphonium salt copolymer, characterized in that, The copolymer includes structural unit A of Formula I, structural unit B of Formula II, and structural unit C of Formula III; In this configuration, R1 and R2 are each independently C1-C4 alkyl groups; R3 is a C1-C4 alkylene group; R4, R5 and R6 are each independently C1-C4 alkyl or aryl groups; X is a halogen; and R7 is H, a C1-C4 alkyl or aryl group.

2. The cationic quaternary phosphonium salt copolymer according to claim 1, wherein, R1 and R2 are each independently C1-C3 alkyl groups, R3 is a C1-C3 alkylene group, and R4, R5, and R6 are each independently C1-C3 alkyl groups or C6-C6 alkyl groups. 10 The aryl group, where X is Cl or Br, and R7 is a C1-C3 alkyl group or a C6-C4 alkyl group. 10 aryl; Preferably, based on the total molar amount of the cationic quaternary phosphonium salt copolymer, the content of structural unit A is 70-95 mol%, preferably 75-92 mol%; the content of structural unit B is 4-25 mol%, preferably 6-18 mol%; and the content of structural unit C is 1-8 mol%, preferably 2-6 mol%.

3. The cationic quaternary phosphonium salt copolymer according to claim 1 or 2, wherein, The weight-average molecular weight of the cationic quaternary phosphonium salt copolymer is 1×10⁻⁶. 4 -1×10 5 g / mol, with a molecular weight distribution of 1.5-3.5; Preferably, the cationic quaternary phosphonium salt copolymer has a weight-average molecular weight of 2 × 10⁻⁶. 4 -5×10 4 g / mol, with a molecular weight distribution of 2-3.

4. The cationic quaternary phosphonium salt copolymer according to any one of claims 1-3, wherein, The 5wt% thermogravimetric temperature of the cationic quaternary phosphonium salt copolymer is ≥210℃, preferably ≥230℃.

5. A method for preparing a cationic quaternary phosphonium salt copolymer, characterized in that, The preparation method includes: (1) In the presence of a solvent and an initiator, isoolefins and arylolefins are subjected to cationic polymerization, and a terminator is added to obtain a solution containing isoolefin-arylolefin copolymers. (2) A halogenating agent is added to the solution containing the isoolefin-arylolefin copolymer to carry out a halogenation reaction to obtain a halogenated isoolefin-arylolefin copolymer solution; (3) Add activator A to the solution of haloisoolefin-arylolefin copolymer to carry out an active functionalization reaction, and then add organophosphorus compound to carry out an ionization reaction to obtain the cationic quaternary phosphonium salt copolymer; The activator A is an olefinic acid compound with the structure shown in Formula IV: R7' is H, C1-C4 alkyl or aryl.

6. The method according to claim 5, wherein, The isoolefin has the structure shown in Formula V, and the arylolefin has the structure shown in Formula VI; Wherein, R1', R2' and R3' are each independently a C1-C4 alkyl group, preferably a C1-C3 alkyl group; Preferably, based on the total amount of the isoolefins and arylolefins, the molar fraction of the arylolefins is 5-30 mol%; more preferably 8-25 mol%. Preferably, the initiator comprises a proton-donating compound, a Lewis acid, and an activator B; Preferably, in the initiator, the molar ratio of the proton-donating compound, the Lewis acid, and the activator B is 0.02-0.5:1:0.005-0.2, more preferably 0.05-0.3:1:0.01-0.

12.

7. The method according to claim 5 or 6, wherein, The conditions for the cationic polymerization include: a polymerization temperature of -80°C to 0°C, preferably -60°C to -20°C; and a polymerization time of 10-90 min, preferably 20-60 min. Preferably, the halogenation reaction is initiated under visible light irradiation. Preferably, the wavelength of the visible light is 590-630 nm; Preferably, the visible light emission mode is pulsed emission; Preferably, the pulse duration of the pulsed light emission is 5-40 seconds, more preferably 10-30 seconds; Preferably, the halogenating agent is an elemental halogen, preferably bromine and / or chlorine, and more preferably bromine.

8. The method according to any one of claims 5-7, wherein, The molar ratio of the halogenating agent to the isoolefin-aryl olefin copolymer based on the structural units provided by the aryl olefin is 1-1.2:1, preferably 1-1.1:1; Preferably, the molar ratio of the activator A to the halogenating agent is 0.05-0.5:1, more preferably 0.1-0.3:1; Preferably, the olefinic compound is a monoolefinic acid, preferably at least one selected from acrylic acid, 2-butenoic acid, 2-pentenoic acid, 2-hexenoic acid, 2-heptenoic acid, 4-methyl-2-hexenoic acid, 5-methyl-2-hexenoic acid and 3-phenyl-2-acrylic acid, more preferably 3-phenyl-2-acrylic acid; Preferably, the organophosphorus compound has the structure shown in Formula VII: R4', R5' and R6' are each independently a C1-C4 alkyl or aryl group; Preferably, the molar ratio of the organophosphorus compound to the halogenating agent is 0.5-0.95:1, more preferably 0.7-0.9:1; Preferably, the conditions for the active functionalization reaction include: a reaction temperature of 60-100℃, more preferably 70-90℃, and a reaction time of 1-5h, more preferably 2-4h; Preferably, the conditions for the ionization reaction include: a reaction temperature of 70-120℃, more preferably 80-100℃; a reaction time of 4-12h, more preferably 6-10h; and a reaction pressure of 0.35-1MPa, more preferably 0.4-0.8MPa.

9. A cationic quaternary phosphonium salt copolymer prepared by the method according to any one of claims 5-8.

10. The use of the cationic quaternary phosphonium salt copolymer according to any one of claims 1-4 or 9 as an antibacterial agent.

11. The cationic quaternary phosphonium salt copolymer of any one of claims 1-4 or 9 is used to inhibit and kill at least one of bacteria, fungi and viruses.

12. An antibacterial plastic, characterized in that, The antibacterial plastic comprises the cationic quaternary phosphonium salt copolymer and plastic as described in any one of claims 1-4 or 9; The cationic quaternary phosphonium salt copolymer is chemically covalently grafted into the plastic.

13. The antibacterial plastic according to claim 12, wherein, Based on 100 parts by weight of plastic, the cationic quaternary phosphonium salt copolymer is 2-8 parts by weight, preferably 4-6 parts by weight; Preferably, the plastic is selected from at least one of PE plastic, PP plastic and PVC plastic.

14. The antibacterial plastic according to claim 13, wherein, The antibacterial plastic has a thermal weight loss temperature of ≥300℃, preferably ≥320℃, at 5wt%.

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