Quaternary phosphonium salt isobutenyl cationic polymer as well as preparation method and application thereof

Abstract

The invention relates to the field of antibacterial functional polymer materials, and discloses a quaternary phosphonium salt type isobutyl cationic polymer as well as a preparation method and application thereof. The preparation method of the polymer comprises the following steps: under a cationic polymerization condition and in the presence of a solvent and a catalyst, isobutene and alkyl styrene are contacted for cationic polymerization, a terminator is added for terminating to obtain a solution containing an isobutene-alkyl styrene copolymer, the solution and a halogenating agent are subjected to a halogenating reaction, and the isobutene-alkyl styrene copolymer is obtained. The preparation method comprises the following steps: preparing a halogenated isobutylene-alkyl styrene copolymer solution, contacting the halogenated isobutylene-alkyl styrene copolymer solution with an organic phosphine compound, carrying out an ionization reaction to obtain a slurry material containing solid particles, carrying out solid-liquid separation to obtain a solid phase, and washing and drying the solid phase with a solvent and deionized water to obtain the quaternary phosphonium salt type isobutylene cationic polymer. The solvent is selected from dichloromethane and / or trichloromethane. The polymer prepared by the method is high in purity, high in quaternary phosphonium salt group content and higher in antibacterial property.

Description

Technical Field

[0001] The present invention relates to the field of antibacterial functional polymer materials, and specifically, to a quaternary phosphonium salt type isobutenyl cationic polymer, a preparation method thereof, and an application thereof. Background Art

[0002] There are two commercially produced isobutenyl random copolymers. One is a copolymer of isobutene and isoprene, which belongs to the unsaturated type; the other is a copolymer of isobutene and p-methylstyrene, which belongs to the saturated type. Both of these copolymers can undergo halogenation reactions to obtain halogenated butyl rubber, and the main application fields are tire inner liners and pharmaceutical stoppers. In addition, as rubber-like elastomer products, these two products are characterized by high molecular weights (weight-average molecular weight Mw is above 500,000), and low contents of copolymerized functional monomers. Generally, the mole fraction of isoprene in the copolymer is <3%, the mole fraction of p-methylstyrene is <5%, and the mole fraction of functional groups is <1.5%.

[0003] The isobutenyl ion polymers disclosed in the literature and patents are generally prepared using commercially available halogenated butyl rubber as the base rubber. For example, Synthesis and characterization of isobutylenen-based ammonium and phosphonium bromide ionomers (Macromolecules, 2004, 37, 7477-7483) and Quaternary ammonium BIMS ionomers (Presented at the 163rd Technical Meeting of the Rubber Division, American Chemical Society, San Francisco, California, April 28-30, 2003) disclose that at 130 °C, in a Banbury mixer, BIIR or BIMS rubber is melt-blended with alkylamines, alkylphosphines, imidazoles, etc., and during this process, a nucleophilic substitution reaction occurs on the allyl bromide functional group in BIIR or the benzyl bromide functional group in BIMS to obtain ion polymers such as ammonium salts, phosphonium salts, and imidazole salts. Or, for example, in An imidazolium-functionalized isobutylene polymer having improved mechanical and barrier properties: synthesis and characterization (Journal of Applied Polymer Science, 2013, 128(5): 2911-2918), the BIIR or BIMS product is dissolved again in an organic solvent for a long-term ionization reaction. Due to the low content of copolymerized functional monomers in BIIR or BIMS rubber, only a limited degree of ionization can be carried out, and the molar content of ionic salts is generally ≤1%, making it difficult to widely expand its application fields. It can often only be used as an ionic rubber in the field of traditional vulcanized rubber products. Summary of the Invention

[0004] The object of the present invention is to overcome the problems in the prior art such as the complex preparation method of quaternary phosphonium salt-type cationic polymers and the low content of quaternary phosphonium salts, and to provide a quaternary phosphonium salt-type isobutenyl cationic polymer, its preparation method and application. In this preparation method, a polymerization reaction is carried out in the presence of a specific solvent and combined with a specific post-treatment method, which can simplify the process flow while significantly increasing the content of quaternary phosphonium salt groups in the polymer, making the polymer have excellent antibacterial properties.

[0005] To achieve the above object, a first aspect of the present invention provides a method for preparing a quaternary phosphonium salt type isobutenyl cationic polymer, characterized in that the preparation method comprises the following steps:

[0006] (i) Under cationic polymerization conditions, in the presence of a solvent and a catalyst, isobutene and alkylstyrene are contacted for cationic polymerization to obtain a solution containing an isobutene-alkylstyrene copolymer;

[0007] (ii) The solution of the isobutene-alkylstyrene copolymer obtained in step (i) is subjected to a halogenation reaction with a halogenating agent to obtain a solution of a halogenated isobutene-alkylstyrene copolymer;

[0008] (iii) The solution of the halogenated isobutene-alkylstyrene copolymer obtained in step (ii) is contacted with an organic phosphorus compound for an ionization reaction to obtain a slurry-like material containing solid particles;

[0009] (iv) The slurry-like material containing solid particles obtained in step (iii) is subjected to solid-liquid separation to obtain a solid phase, and the solid phase is washed and dried with a solvent and deionized water to obtain the quaternary phosphonium salt type isobutenyl cationic polymer;

[0010] Wherein, the solvent is selected from dichloromethane and / or chloroform.

[0011] A second aspect of the present invention provides a quaternary phosphonium salt type isobutenyl cationic polymer prepared by the above preparation method.

[0012] A third aspect of the present invention provides an application of the above quaternary phosphonium salt type isobutenyl cationic polymer as an antibacterial agent.

[0013] Through the above technical solutions, the quaternary phosphonium salt type isobutenyl cationic polymer, its preparation method and application provided by the present invention can achieve the following beneficial effects:

[0014] In the present invention, in the preparation method of the quaternary phosphonium salt type isobutenyl cationic polymer, in the presence of dichloromethane and / or chloroform, isobutene and alkylstyrene are subjected to cationic polymerization, which can improve the polymerization activity, and the solvent does not participate in the halogenation reaction. Not only can the activator in the catalyst be omitted, but also the halogenation reaction efficiency can be improved, the occurrence of side reactions can be reduced, so that in the ionization reaction process of the obtained copolymer, the solid product always exists in the form of small particles, which is easy to remove the unreacted organic phosphine wrapped in the particles, and the product purity is high; and there is no solvent replacement process in the whole preparation process, which simplifies the production process; the obtained polymer is an antibacterial agent containing phosphonium salt functional groups at the same time, with better antibacterial performance, and can be used as an antibacterial agent to prepare antibacterial polymer materials with stable, lasting, safe and low-toxic antibacterial properties, such as antibacterial plastics, antibacterial rubbers, antibacterial fibers and antibacterial coatings, and can effectively inhibit and kill bacteria, fungi, viruses, etc. Detailed embodiments

[0015] In the ranges disclosed herein, the endpoints and any values are not limited to the exact 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 each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0016] The first aspect of the present invention provides a preparation method of a quaternary phosphonium salt type isobutenyl cationic polymer, which is characterized in that the preparation method includes the following steps:

[0017] (i) Under cationic polymerization conditions, in the presence of a solvent and a catalyst, isobutene and alkylstyrene are contacted for cationic polymerization, and then a terminator is added for termination to obtain a solution containing an isobutene-alkylstyrene copolymer;

[0018] (ii) The solution of the isobutene-alkylstyrene copolymer obtained in step (i) is subjected to a halogenation reaction with a halogenating agent to obtain a solution of a halogenated isobutene-alkylstyrene copolymer;

[0019] (iii) The solution of the halogenated isobutene-alkylstyrene copolymer obtained in step (ii) is contacted with an organic phosphorus compound for an ionization reaction to obtain a slurry-like material containing solid particles;

[0020] (iv) The slurry-like material containing solid particles obtained in step (iii) is subjected to solid-liquid separation to obtain a solid phase, and the solid phase is washed and dried with a solvent and deionized water to obtain the quaternary phosphonium salt type isobutenyl cationic polymer;

[0021] Among them, the solvent is selected from dichloromethane and / or chloroform.

[0022] In the present invention, in the preparation method of the quaternary phosphonium salt type isobutenyl cationic polymer, in the presence of dichloromethane and / or chloroform, isobutene and alkylstyrene are subjected to cationic polymerization, which can provide polymerization activity, and the solvent does not participate in the halogenation reaction. It can not only omit the activator in the catalyst, but also improve the halogenation reaction efficiency, reduce the occurrence of side reactions, so that the obtained copolymer always exists in the form of small particles during the ionization reaction process, and it is easy to remove the unreacted organic phosphine wrapped in the particles, and the product has high purity; and there is no solvent replacement process during the whole preparation process, which simplifies the production process; the obtained polymer is an antibacterial agent containing phosphonium salt functional groups at the same time, with better antibacterial performance, and can be used as an antibacterial agent to prepare antibacterial polymer materials with stable, lasting, safe and low-toxic antibacterial properties, such as antibacterial plastics, antibacterial rubbers, antibacterial fibers and antibacterial coatings, and can effectively inhibit and kill bacteria, fungi, viruses, etc.

[0023] Furthermore, when the quaternary phosphonium salt type isobutenyl cationic polymer is prepared by the method provided by the present invention, due to the high halogenation reaction efficiency of this method, the halogen content in the polymer is high when the same amount of halogen is added, which makes more quaternary phosphonium salt functional groups be introduced during the subsequent ionization reaction process, and the antibacterial performance of the obtained polymer is further improved.

[0024] In a preferred embodiment of the present invention, the solvent is dichloromethane.

[0025] In the present invention, there is no special limitation on the amount of the solvent, and it can be a conventional choice in the art. Generally, the amount of the solvent is such that the total monomer concentration is 5-50 wt%, preferably 10-35 wt%, more preferably 15-25 wt%.

[0026] In the present invention, the solid-liquid separation is carried out on the slurry-like material containing solid particles obtained in step (iii), the solvent in the material is removed to obtain a solid phase. Further, the obtained solid phase is washed with a solvent, and the unreacted organic phosphine compound remaining in the product can be removed to improve the purity of the product; furthermore, the solid phase washed with the solvent is washed with deionized water, and the complex generated in the termination reaction can be removed to further improve the product purity and reduce the content of metal aluminum ions in the final product.

[0027] In the present invention, there is no special requirement for the order of solvent washing and deionized water washing, and it can be adjusted according to actual needs.

[0028] According to the present invention, in step (iv), the volume of the washing solvent is 0.5-2 times the volume of the solid phase;

[0029] In the present invention, when the volume of the washing solvent is controlled to meet the above range, not only can the effective removal of the organophosphorus compound be ensured, but also the consumption of the solvent can be saved.

[0030] Furthermore, the volume of the washing solvent is 1 - 2 times the volume of the solid phase.

[0031] According to the present invention, the number of times of solvent washing is 1 - 3 times.

[0032] According to the present invention, in step (iv), the volume of the deionized water for washing is 1 - 2 times the volume of the solid phase.

[0033] In the present invention, when the volume of the deionized water for washing is controlled to meet the above range, not only can the residual catalyst complex in the product be effectively removed, but also the consumption of the deionized water can be saved.

[0034] According to the present invention, the number of times of deionized water washing is 1 - 2 times;

[0035] Preferably, the solvent washing and the deionized water washing are each independently spray washing.

[0036] In the present invention, the solid - liquid separation is centrifugation and / or filtration.

[0037] In a specific embodiment of the present invention, the slurry - like material containing solid particles obtained in step (iii) is centrifuged and / or filtered using a centrifuge and / or a filter machine with spray washing to remove the solvent in the slurry - like material, and then spray - washed 1 - 3 times with dichloromethane and / or chloroform to remove the unreacted organophosphorus compound remaining in the product, so that the purity of the product is significantly improved; then the above - mentioned product is spray - washed 1 - 2 times with deionized water to remove the complex generated in the termination reaction, so as to further improve the product purity and reduce the content of metal aluminum ions in the final product.

[0038] In the present invention, there is no particular limitation on the centrifuge and / or filter machine with spray washing. The centrifuge with spray - washing function or the filter machine with spray - washing function in the prior art is applicable to the present invention. Specifically, the centrifuge with spray washing is preferably a filter centrifuge, such as a horizontal spiral filter centrifuge, a vertical spiral filter centrifuge, a horizontal scraper discharge centrifuge, etc., and preferably a horizontal spiral filter centrifuge. The filter machine with spray washing can be a filter - washing integrated machine, etc.

[0039] According to the present invention, the weight - average molecular weight of the isobutene - alkylstyrene copolymer is 1×10 4 - 1×10 5 g / mol, preferably 2×10 4 - 8×104 g / mol. The molecular weight distribution of the isobutene-alkylstyrene copolymer is 2 - 3.5, preferably 2.2 - 3.

[0040] According to the present invention, based on the total amount of substance of the isobutene and the alkylstyrene, the molar fraction of the alkylstyrene is 5 mol% - 25 mol%; preferably 8 - 20 mol%.

[0041] In the present invention, examples of the alkylstyrene may include but are not limited to: p-methylstyrene, m-methylstyrene, p-ethylstyrene, and p-tert-butylstyrene. Preferably, the alkylstyrene is p-methylstyrene.

[0042] According to the present invention, the cationic polymerization conditions include: the polymerization temperature is -80°C to 0°C, preferably -60°C to -20°C; the polymerization time is 10 - 90 min, preferably 20 - 60 min.

[0043] In the present invention, there is no particular limitation on the catalyst used for cationic polymerization. Conventional cationic polymerization catalysts in the art can be used. For example, the catalyst includes a compound capable of providing protons and a Lewis acid. This catalyst has high catalytic efficiency, can make the monomer conversion rate reach 100%, and can thus be directly used in the halogenation reaction. In the present invention, the molar ratio of the compound capable of providing protons to the Lewis acid in the catalyst is preferably 0.005 - 0.05:1. Specifically, in the present invention, the catalyst can be a hydrogen chloride / dichloroethylaluminum / (HCl / EADC) system. There is no particular limitation on the amount of the catalyst used, and it can be appropriately selected according to specific polymerization conditions so as to initiate the complete polymerization of the monomers.

[0044] In the present invention, there is no particular limitation on the type of terminator, and conventional terminators in the art can be used. Preferably, the terminator is a saturated fatty alcohol. More preferably, the terminator is selected from at least one of saturated monohydric fatty alcohols having 1 - 5 carbon atoms, saturated dihydric fatty alcohols having 2 - 4 carbon atoms, and the saturated fatty alcohol represented by formula (1).

[0045] Wherein, n is 1 - 3.

[0046] In a specific embodiment of the present invention, the saturated monohydric fatty alcohol is selected from at least one of methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, n-pentanol, and isopentanol; the saturated dihydric fatty alcohol is one or more of ethylene glycol, propylene glycol, 1,2-butanediol, 1,3-butanediol, and 1,4-butanediol; in formula (1), R1 is a straight-chain or branched-chain alkyl group with 2 to 3 carbon atoms. In a further preferred case, the saturated fatty alcohol shown in formula (1) is one or more of dipropylene glycol, triethylene glycol, and tripropylene glycol, and more preferably triethylene glycol (TEG).

[0047] In a preferred embodiment of the present invention, the terminator is mixed with a solvent and added to the cationic polymerization product in the form of a terminator solution. Preferably, the solvent is selected from dichloromethane and / or chloroform. Specifically, based on the total mass of the terminator solution, the mass content of the terminator is 2 - 5 wt%. There is no particular limitation on the amount of the terminator solution used, and the amount of the terminator solution is based on being able to completely neutralize the Lewis acid in the catalyst solution. Generally, the molar ratio of the terminator in the terminator solution to the Lewis acid in the catalyst is 2 - 2.5:1. During the termination reaction process, the terminator reacts with the Lewis acid to form a complex, which temporarily remains in the polymer and can be dissolved in water and removed during the subsequent water washing process of the antibacterial agent product.

[0048] In the present invention, the halogenating agent can be a conventional substance in the art that can cause some hydrogen atoms in the iso-monoolefin-aryl olefin copolymer to be replaced by halogen atoms. Preferably, the halogenating agent is a halogen element, such as bromine and / or chlorine. More preferably, the halogenating agent is bromine.

[0049] In the present invention, in step (ii), the solution of the isobutene-alkylstyrene copolymer is subjected to a halogenation reaction. The structural units from alkylstyrene in the copolymer macromolecular chain undergo halogen substitution reactions, and it can cause the alkyl hydrogens on the benzene ring of alkylstyrene and the tertiary carbon hydrogens on the main chain connected to the benzene ring to undergo halogenation reactions, thereby forming side-chain alkyl halide structures and main-chain tertiary carbon halide structures in the copolymer macromolecular chain. Specifically, after halogenation, the structural units from alkylstyrene form the following three structures:

[0050]

[0051] In the present invention, the halogenation reaction can be carried out under conventional conditions as long as it can cause the isobutene-alkylstyrene copolymer to undergo a halogenation reaction. For example, the halogenation reaction is carried out in the presence of at least one radical initiator, or the halogenation reaction is carried out under photo-initiation conditions. Preferably, the halogenation reaction is carried out under photo-initiation conditions.

[0052] In the present invention, when the halogenation reaction is carried out under photo-initiation conditions, the light irradiation conditions are such that they can initiate the halogenation reaction of the isobutene-alkylstyrene copolymer. According to a preferred embodiment of the present invention, the conditions for photo-initiation include: the light wavelength is 560-630 nm, the light intensity is 80-200 mW, and the light emission mode is pulsed light emission. The pulsed light emission means that the light source emits light waves and stops emitting light waves at equal time intervals and alternates. Specifically, the pulse time of the pulsed light emission is 5-40 s, preferably 10-30 s.

[0053] In the present invention, there is no special limitation on the temperature of the halogenation reaction, and it can be a conventional choice; the time of the substitution reaction can be selected according to the reaction temperature and the expected degree of substitution reaction.

[0054] In the present invention, the amount of halogen atoms introduced into the molecular chain of the isobutene-alkylstyrene copolymer can be selected according to the use occasion of the finally prepared polymer. According to a preferred embodiment of the present invention, the molar ratio of the halogenating agent to the alkylstyrene structural unit in the isobutene-alkylstyrene copolymer is 0.8-1.5:1, preferably 1-1.2:1.

[0055] In the present 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 polymer solution to carry out the halogenation reaction, so as to realize the regulation of the selectivity of the halogenation reaction. Preferably, the organic solvent is selected from dichloromethane and / or chloroform. In the present invention, the organic solvent does not participate in the halogenation reaction, so the utilization rate of the halogen is as high as more than 95%.

[0056] In a specific embodiment of the present invention, the halogen solution is slowly added dropwise to the copolymer solution, and under the visible light irradiation of pulsed light emission of an LED light source with a wavelength of 560 nm-630 nm, a photo-halogenation reaction is carried out to obtain a halogenated copolymer solution. The structural units derived from aryl olefins in the copolymer macromolecular chain undergo halogen substitution reactions, and it is possible to cause the alkyl hydrogens on the aromatic ring of the aryl olefin and the tertiary carbon hydrogens on the main chain connected to the aromatic ring to undergo halogenation reactions, thereby forming side-chain alkyl halide structures and main-chain tertiary carbon halide structures in the polymer macromolecular chain.

[0057] In the present invention, the dropping rate of the halogen solution is 50-100 drops / min.

[0058] In the present invention, the dropping rate of the halogen solution is controlled so that the time of the halogenation reaction is 30-150 min, preferably 60-120 min.

[0059] To neutralize the hydrogen halide generated during the halogenation reaction, a certain amount of basic compounds, such as solid powders of sodium carbonate, sodium bicarbonate, calcium carbonate, magnesium carbonate, calcium oxide, magnesium oxide, etc., can be added to the copolymer solution, and sodium bicarbonate is preferably used. The halogenated copolymer solution is centrifuged or filtered to remove the solid halogen salt compounds. The present invention does not have special limitations on the centrifugation or filtration equipment, and the centrifugation or filtration equipment commonly used by those skilled in the art can be selected. The present invention does not have special limitations on the centrifugation or filtration conditions, and the conditions commonly used by those skilled in the art can be adopted. According to a preferred embodiment of the present invention, a settling centrifuge is selected, preferably a tubular settling centrifuge.

[0060] According to the present invention, the organophosphorus compound is a tertiary phosphine compound. For example, the organophosphorus compound is selected from trimethylphosphine, triethylphosphine, tripropylphosphine, tributylphosphine, tripentylphosphine, tricyclopentylphosphine, trihexylphosphine, tricyclohexylphosphine, triheptylphosphine, trioctylphosphine, trinonylphosphine, tridecylphosphine, triphenylphosphine, etc., and triphenylphosphine is preferably used.

[0061] According to the present invention, the molar ratio of the organophosphorus compound to the halogenating agent is 1-1.5:1.

[0062] In the present invention, when the molar ratio of the organophosphorus compound to the halogenating agent is controlled to meet the above range, the organophosphorus compound can be fully introduced onto the halogenated isobutene-alkylstyrene copolymer through an ionization reaction, so that the prepared quaternary phosphonium salt type isobutenyl cationic polymer has a high quaternary phosphonium salt group content.

[0063] Furthermore, the molar ratio of the organophosphorus compound to the halogenating agent is 1.1-1.2:1.

[0064] According to the present invention, the conditions of the ionization reaction include: reflux reaction for 4-20 hours at a temperature of 60-120°C and a pressure of 0.2-0.9 MPa.

[0065] In the present invention, when the conditions of the ionization reaction are controlled to meet the above range, the ionization reaction can have a high reaction rate, shorten the ionization reaction time, and improve the reaction efficiency of the ionization reaction.

[0066] In the present invention, preferably, the ionization reaction is carried out in the presence of a protective gas.

[0067] In a specific embodiment of the present invention, the organophosphorus compound is added to the solution of the halogenated isobutene-alkylstyrene copolymer, and the first ionization reaction is carried out in the presence of a protective gas. The reaction temperature is 80-100°C, the pressure is 0.35-0.6 MPa, and the reaction time is 6-15 h.

[0068] The second aspect of the present invention provides a quaternary phosphonium salt type isobutenyl cationic polymer prepared by the above preparation method.

[0069] According to the present invention, the polymer comprises structural unit I, structural unit II and structural unit III;

[0070] The structural unit I has at least one of the structures shown in formula (1) and / or formula (2) and optionally the structure shown in formula (3); the structural unit II has the structure shown in formula (4); the structural unit III has the structure shown in formula (5);

[0071]

[0072] wherein, R1 is an alkylene group with 1-4 carbon atoms, and R2, R3, and R4 are each independently a straight-chain alkyl group with 1- 10 carbon atoms, a branched-chain alkyl group with 1- 10 carbon atoms, a cycloalkyl group with 3- 10 carbon atoms or an aryl group with 6- 10 carbon atoms, R5 is an alkyl group with 1-4 carbon atoms, and X is a halogen.

[0073] In the present invention, the quaternary phosphonium salt type isobutenyl cationic polymer comprises a macromolecular skeleton composed of a main structural unit provided by isobutene and a functional structural unit provided by alkylstyrene. A quaternary phosphonium salt functional group is introduced simultaneously on the side chain and the main chain of the alkylstyrene unit in the polymer, so that the polymer has a more satisfactory higher degree of ionization, and can be used as an antibacterial agent to prepare stable, durable, safe and low-toxic antibacterial polymer materials, such as antibacterial plastics, antibacterial rubbers, antibacterial fibers and antibacterial coatings, and can effectively inhibit and kill bacteria, fungi, viruses, etc.

[0074] Furthermore, R1 is methylene or ethylene, R2, R3, and R4 are each independently a straight-chain alkyl group with 1-8 carbon atoms, a cycloalkyl group with 5-8 carbon atoms or an aryl group with 6-8 carbon atoms, R5 is methyl or ethyl, and X is Cl or Br.

[0075] Still further, R1 is methylene, R2, R3, and R4 are each independently a straight-chain alkyl group with 1-8 carbon atoms, cyclopentyl, cyclohexyl or phenyl, R5 is methyl, and X is Br.

[0076] In the present invention, by using the method provided by the present invention, more quaternary phosphonium salt functional groups can be introduced into the polymer, and thus the polymer has more excellent antibacterial properties. Specifically, based on the total molar amount of the polymer, the content of the quaternary phosphonium salt functional group is 5-25 mol%, preferably 8-20 mol%.

[0077] In a preferred embodiment of the present invention, based on the total molar amount of the polymer, the content of the quaternary phosphonium salt functional group is 15.5 - 25 mol%, preferably 15.5 - 20 mol%.

[0078] According to the present invention, based on the total molar amount of the polymer, the content of the side-chain benzyl quaternary phosphonium salt group is 3.5 - 16 mol%, preferably 5 - 14 mol%; the content of the main-chain tertiary carbon quaternary phosphonium salt group is 1.5 - 9 mol%, preferably 3 - 6 mol%.

[0079] In the present invention, the main-chain tertiary carbon quaternary phosphonium salt functional group refers to the quaternary phosphonium salt functional group on the main chain of alkylstyrene, including the quaternary phosphonium salt group in the structure shown in formula (1) and the quaternary phosphonium salt group on the main chain of alkylstyrene in the structure shown in formula (2). In the present invention, the content of the main-chain quaternary phosphonium salt group is the sum of the content of the quaternary phosphonium salt group in the structure shown in formula (1) and the content of the quaternary phosphonium salt group on the main chain in the structure shown in formula (2).

[0080] In the present invention, the side-chain quaternary phosphonium salt functional group refers to the quaternary phosphonium salt group on the side chain of alkylstyrene, including the quaternary phosphonium salt group in the structure shown in formula (3) and the quaternary phosphonium salt group on the side chain of alkylstyrene in the structure shown in formula (2). In the present invention, the content of the side-chain benzyl quaternary phosphonium salt group is the sum of the content of the quaternary phosphonium salt group in the structure shown in formula (3) and the content of the quaternary phosphonium salt group in the side chain of the structure shown in formula (2).

[0081] According to the present invention, based on the total molar amount of the polymer, the content of the structural unit I is 3.5 - 22 mol%, the content of the structural unit II is 1.5 - 10 mol%, and the content of the structural unit III is 75 - 95 mol%.

[0082] Furthermore, based on the total molar amount of the polymer, the content of the structural unit I is 5 - 18 mol%, the content of the structural unit II is 3 - 6 mol%, and the content of the structural unit III is 80 - 92 mol%.

[0083] In the present invention, the quaternary phosphonium salt type isobutenyl cationic polymer contains the structural unit I shown in formula (2), and this structural unit contains both side-chain quaternary phosphonium salt functional groups and main-chain quaternary phosphonium salt functional groups, ultimately making the total molar content of the quaternary phosphonium salt functional groups in the quaternary phosphonium salt type isobutenyl cationic polymer higher than the molar content of the structural unit I.

[0084] According to the present invention, the thermal weight loss temperature of 5 wt% of the quaternary phosphonium salt type isobutenyl cationic polymer ≥ 200 °C, preferably ≥ 220 °C;

[0085] According to the present invention, the content of aluminum ions in the quaternary phosphonium salt type isobutenyl cationic polymer is less than 10 ppm, preferably less than 5 ppm.

[0086] The third aspect of the present invention provides an application of the above-mentioned quaternary phosphonium salt type isobutenyl cationic polymer as an antibacterial agent.

[0087] The present invention will be described in detail below through examples.

[0088] The present invention will be described in detail below through examples.

[0089] In the following examples, the molecular weight and molecular weight distribution index of the polymer were measured using an LC-20A liquid phase gel permeation chromatograph (GPC) produced by Shimadzu Corporation of Japan.

[0090] The content of each structural unit in the polymer and the content of quaternary phosphonium salt in the antibacterial agent were measured using an AVANCE400 nuclear magnetic resonance spectrometer produced by Bruker Corporation of Switzerland.

[0091] Method for measuring polymerization conversion rate: The ratio of the mass of the polymer obtained after polymerization to the mass of the monomer added.

[0092] Calculation method for halogen utilization rate: For a halogenation substitution reaction proceeding by a free radical mechanism, when theoretically 100% of the halogen undergoes a hydrogen substitution reaction, 50% of the halogen is substituted onto the polymer. The ratio of the actually measured halogen content of the polymer to the theoretical halogen content is the halogen utilization rate. Since the tertiary carbon halogen in the main chain of the halogenated polymer has no characteristic peak in the nuclear magnetic resonance hydrogen spectrum and the halogen content at this position cannot be obtained, but the content of quaternary phosphonium salt after the ionization reaction can be measured. Therefore, the ratio of the actually measured content of quaternary phosphonium salt in the antibacterial agent product to the theoretical halogen content is the halogen utilization rate.

[0093] The content of metal Al element in the sample was measured using an inductively coupled plasma atomic emission spectrometer (ICP-OES), and the execution standard was JYT015-1996.

[0094] The thermogravimetric analysis of the sample was carried out using a METTLER TGA / DSC1 instrument, with a test temperature range of 25-600 °C, a heating rate of 10 °C / min, and a nitrogen atmosphere of 50 mL / min.

[0095] Example 1

[0096] (i) 2 L of dichloromethane, 8.5 mol of isobutene (IB), and 1.7 mol of p-methylstyrene (p-MeSt) were sequentially added to a 5 L polymerization kettle equipped with a stirrer, a jacket, and an internal cooling tube. Based on the total amount of isobutene and alkylstyrene, the molar fraction of alkylstyrene was 16.7 mol%. The stirrer was turned on to mix evenly, and the temperature of the monomer solution was lowered to -40 °C using the coolant in the jacket and the internal cooling tube. 90 mL of a catalyst solution (molar ratio of HCl / EADC was 0.01) was slowly added, and the polymerization reaction temperature was controlled at -40 ± 2 °C using the coolant in the jacket and the internal cooling tube of the polymerization kettle. After 40 min of polymerization reaction, 83 mL of a dichloromethane solution of a terminator (mass concentration was 3%, molar ratio of terminator triethylene glycol (TEG) to dichloroethylaluminum EADC was 2) was added. The weight-average molecular weight of the polymer was determined by GPC to be 46,400 g / mol, the molecular weight distribution coefficient was 2.68, the conversion rate of the polymerization monomer was 100%, and the molar fraction of p-methylstyrene in the copolymer was 16.7%.

[0097] (ii) The polymer solution was heated to 30 °C, and 160 g of sodium bicarbonate powder was added. 96 mL of liquid bromine was added to a constant-pressure dropping funnel containing 300 mL of dichloromethane (molar ratio of liquid bromine to p-methylstyrene in the polymer was 1.1:1). Photobromination reaction was carried out using a 595 nm light source with a light intensity of 100 mW and a pulse time of 20 s. The light source was turned on for the bromination reaction, and the liquid bromine solution was added at a rate of 80 drops / min. After the addition of the liquid bromine solution was complete, the reaction was continued for 5 minutes, the light source was turned off, and the reaction was stopped. The bromination reaction time was 90 min.

[0098] (iii) The brominated polymer solution was separated by a tubular settling centrifuge to remove the insoluble precipitate. The obtained clear liquid was transferred to a 5 L pressure-resistant glass stirring kettle with a jacket. The stirrer was turned on, and 0.54 kg of triphenylphosphine (molar ratio of triphenylphosphine to liquid bromine was 1.1:1) was added. The reaction system was heated to 90 °C, the reaction pressure was maintained at 0.45 MPa, and reflux reaction was carried out for 10 h to obtain a slurry-like material.

[0099] (iv) The solvent was removed by centrifugation using a horizontal spiral filtration centrifuge, sprayed and washed with fresh solvent, and then separated again. The volume of the fresh solvent was 1.2 times the volume of the solid particles after the solvent was removed, and the number of washing times was 2; then it was sprayed and washed with deionized water and separated again. The volume of the deionized water was 2 times the volume of the solid particles, and the number of washing times was 1. The obtained solid particles were vacuum dried at 60 °C for 6 h to obtain a quaternary phosphonium salt-type isobutenyl cationic polymer. The content of side-chain benzyl quaternary phosphonium salt in the product was 12.6 mol% by NMR analysis, the content of main-chain tertiary carbon quaternary phosphonium salt was 5.4 mol%, and the total quaternary phosphonium salt content was 18 mol%. The utilization rate of halogen was calculated to be 98.2%.

[0100] The content of metallic Al ions in the product was determined to be 2.6 ppm by using an inductively coupled plasma atomic emission spectrometer.

[0101] Examples 2 - 10

[0102] The quaternary phosphonium salt type isobutenyl cationic polymer was prepared according to the method of Example 1, except that: the dosages of the materials in each step and the specific process conditions were different from those in Example 1, as specifically shown in Table 1. The test results are shown in Table 2.

[0103] Comparative Example 1

[0104] The quaternary phosphonium salt type isobutenyl cationic polymer was prepared according to the method of Example 1, except that: in step iv, it was only washed with a solvent, and the preparation parameters are shown in Table 1, and the measurement results are shown in Table 2.

[0105] Comparative Example 2

[0106] The quaternary phosphonium salt type isobutenyl cationic polymer was prepared according to the method of Example 1, except that: in step iv, it was only washed with deionized water, and the preparation parameters are shown in Table 1, and the measurement results are shown in Table 2.

[0107] Comparative Example 3

[0108] The quaternary phosphonium salt type isobutenyl cationic polymer was prepared according to the method of Example 1, except that: in step i, hexane was used as the solvent, and the preparation parameters are shown in Table 1, and the measurement results are shown in Table 2.

[0109] Table 1

[0110]

[0111] Continued Table 1

[0112]

[0113]

[0114] Table 2

[0115]

[0116]

[0117] 1 It refers to the molar content of p-methylstyrene in the isobutene - alkylstyrene copolymer

[0118] Continued Table 2

[0119]

[0120] 2Refers to the content of Al ions in the phosphonium salt type isobutenyl cationic polymer

[0121] From the results in Table 1 and Table 2, it can be seen that compared with Comparative Example 1 using only solvent washing and Comparative Example 2 using only deionized water washing, in Examples 1-10 of the present invention, washing with both solvent and deionized water can significantly reduce the content of Al ions and unreacted organic phosphine compounds in the final product, making the prepared phosphonium salt type isobutenyl cationic polymer have a high 5wt% thermal weight loss temperature.

[0122] Compared with Comparative Example 3, in Examples 1-10 of the present invention, dichloromethane is used as the solvent for cationic polymerization, and the halogen utilization rate is high during the halogenation process, which is beneficial to introducing more phosphonium salt functional groups into the polymer, making the prepared phosphonium salt type isobutenyl cationic polymer have a high content of phosphonium salt functional groups.

[0123] Furthermore, by comparing Examples 1-9 and Example 10, it can be found that by controlling the conditions of the ionization reaction, the content of phosphonium salt functional groups in the phosphonium salt type isobutenyl cation salt can be increased, further improving the antibacterial performance of the polymer.

[0124] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the technical concept scope of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A preparation method of a phosphonium salt type isobutenyl cationic polymer, characterized in that, The preparation method comprises the following steps: (i) Under cationic polymerization conditions, in the presence of a solvent and a catalyst, isobutene and alkylstyrene are contacted for cationic polymerization, and then a terminator is added for termination to obtain a solution containing an isobutene-alkylstyrene copolymer; (ii) The solution of the isobutene-alkylstyrene copolymer obtained in step (i) is subjected to a halogenation reaction with a halogenating agent to obtain a solution of a halogenated isobutene-alkylstyrene copolymer; (iii) The solution of the halogenated isobutene-alkylstyrene copolymer obtained in step (ii) is contacted with an organic phosphine compound for an ionization reaction to obtain a slurry-like material containing solid particles; (iv) The slurry-like material containing solid particles obtained in step (iii) is subjected to solid-liquid separation to obtain a solid phase, and the solid phase is washed and dried with a solvent and deionized water to obtain the quaternary phosphonium salt type isobutenyl cationic polymer; Wherein, the solvent is selected from dichloromethane and / or chloroform.

2. The preparation method according to claim 1, wherein The solvent is dichloromethane; Preferably, in step (iv), the volume of the solvent for washing is 0.5-2 times the volume of the solid phase; Preferably, the number of times of solvent washing is 1-3 times; Preferably, in step (iv), the volume of deionized water for washing is 1-2 times the volume of the solid phase; Preferably, the number of times of deionized water washing is 1-2 times; Preferably, the solvent washing and the deionized water washing are each independently spray washing.

3. The preparation method according to claim 1 or 2, wherein The weight-average molecular weight of the isobutene-alkylstyrene copolymer is 1×10 4 -1×10 5 g / mol; Preferably, the molecular weight distribution of the isobutene-alkylstyrene copolymer is 2-3.5; Preferably, based on the total amount of substance of the isobutene and the alkylstyrene, the molar fraction of the alkylstyrene is 5 mol%-25 mol%; Preferably, the cationic polymerization conditions include: the polymerization temperature is -80°C to 0°C, preferably -60°C to -20°C; the polymerization time is 10-90 min, preferably 20-60 min.

4. The preparation method according to any one of claims 1 to 3, wherein The halogenating agent is a halogen element, preferably bromine; Preferably, the halogenation reaction is carried out under photoinitiation conditions; Preferably, the conditions of the halogenation reaction include: the halogenation reaction time is 30-150 min, preferably 60-120 min; Preferably, the molar ratio of the halogenating agent to the alkylstyrene structural unit in the isobutene-alkylstyrene copolymer is 0.8-1.5:1, preferably 1-1.2:

1.

5. The preparation method according to any one of claims 1-4, wherein, The organic phosphine compound is a tertiary phosphine compound; Preferably, the molar ratio of the organic phosphine compound to the halogenating agent is 1-1.5:1, preferably 1.1-1.2:1; Preferably, the conditions of the ionization reaction include: reflux reaction for 4-20 hours at a temperature of 60-120°C and a pressure of 0.2-0.9 MPa.

6. A quaternary phosphonium salt type isobutenyl cationic polymer prepared by the preparation method according to any one of claims 1-5.

7. The phosphonium salt type isobutenyl cationic polymer according to claim 6, wherein The polymer comprises structural unit I, structural unit II and structural unit III; The structural unit I has at least one of the structures shown in formula (1) and / or formula (2) and optionally the structure shown in formula (3); the structural unit II has the structure shown in formula (4); the structural unit III has the structure shown in formula (5); Among them, R1 is an alkylene group with 1 to 4 carbon atoms, and R2, R3, and R4 are each independently a straight-chain alkyl group with 1 to 10 carbon atoms, a branched-chain alkyl group with 1 to 10 carbon atoms, a cycloalkyl group with 3 to 10 carbon atoms or an aryl group with 6 to 10 carbon atoms, R5 is an alkyl group with 1 to 4 carbon atoms, and X is a halogen.

8. The phosphonium salt type isobutenyl cationic polymer according to claim 6 or 7, wherein, R1 is methylene or ethylene, R2, R3, and R4 are each independently a straight-chain alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, or an aryl group having 6 to 8 carbon atoms, R5 is methyl or ethyl, and X is Cl or Br; Preferably, R1 is methylene, R2, R3, and R4 are each independently a straight-chain alkyl group having 1 to 8 carbon atoms, cyclopentyl, cyclohexyl, or phenyl, R5 is methyl, and X is Br.

9. The phosphonium salt type isobutenyl cationic polymer according to any one of claims 6-8, wherein Based on the total molar amount of the polymer, the content of the quaternary phosphonium salt functional group is 5-25 mol%, preferably 8-20 mol%.

10. The phosphonium salt type isobutenyl cationic polymer according to any one of claims 6-9, wherein, Based on the total molar amount of the polymer, the content of the side-chain benzyl quaternary phosphonium salt group is 3.5-16 mol%, and the content of the main-chain tertiary carbon quaternary phosphonium salt group is 1.5-9 mol%; Preferably, based on the total molar amount of the polymer, the content of the side-chain benzyl quaternary phosphonium salt is 5-14 mol%, and the content of the main-chain tertiary carbon quaternary phosphonium salt is 3-6 mol%.

11. The phosphonium salt type isobutenyl cationic polymer according to any one of claims 6-10, wherein, Based on the total molar amount of the polymer, the content of the structural unit I is 3.5-22 mol%, the content of the structural unit II is 1.5-10 mol%, and the content of the structural unit III is 75-95 mol%; Preferably, based on the total molar amount of the polymer, the content of the structural unit I is 5-18 mol%, the content of the structural unit II is 3-6 mol%, and the content of the structural unit III is 80-92 mol%.

12. The phosphonium salt type isobutenyl cationic polymer according to any one of claims 6-11, wherein, The thermal weight loss temperature of 5 wt% of the quaternary phosphonium salt type isobutenyl cation polymer ≥ 200 °C, preferably ≥ 220 °C.

13. Use of the quaternary phosphonium salt type isobutenyl cation polymer according to any one of claims 6-12 as an antibacterial agent.

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