A sulfonium polymer-based antibacterial polyurethane emulsion and its preparation method and application

Abstract

The invention discloses a sulfonium polymer-based antibacterial polyurethane emulsion, a preparation method thereof, and an application thereof. In the invention, a sulfonium polymer and a polyol are first blended, and then a prepolymer is generated with a diisocyanate monomer. The sulfonium polymer is introduced into the main chain of the polyurethane, and then chain extension, neutralization, dispersion and emulsification are performed to form an aqueous polyurethane emulsion. The sulfonium polymer-based antibacterial polyurethane emulsion prepared by the invention has excellent antibacterial properties, mechanical properties, and biocompatibility. The sulfonium polymer prepared by the invention contains hydroxyl groups and can undergo a cross-linking reaction with isocyanate groups. Compared with adding the sulfonium polymer during the chain extension process, the invention first mixes the sulfonium polymer and the polyol and then reacts with the diisocyanate. By introducing the sulfonium polymer into the main chain of the polyurethane, the emulsion has more lasting antibacterial properties and more excellent mechanical properties.

Description

Technical Field

[0001] The present invention relates to the technical field of polyurethane emulsion synthesis, and in particular to a sulfonium polymer-based antibacterial polyurethane emulsion, a preparation method thereof and an application thereof. Background Art

[0002] Waterborne polyurethane is an environmentally friendly, polymeric elastic coating popular for its safety and low volatility. This coating offers significant ease of application and effectively forms good adhesion to a variety of substrates, including polymers, cement, metal, and stone. Its superior properties include water resistance, UV aging resistance, chemical corrosion resistance, and flexibility, leading to its widespread use in a variety of applications, including textile finishing, leather processing, adhesives, building materials, and medical devices. However, waterborne polyurethane lacks antimicrobial properties, making it a breeding ground for microbial growth during use. This drawback severely limits its application in areas with high hygiene requirements, such as medical devices, building interiors, and textiles.

[0003] For example, Chinese patent document CN102604002A discloses a method for preparing a multifunctional waterborne polyurethane-quaternary ammonium salt polymer. The method comprises mixing a polyol, a diol, and a polyisocyanate, reacting the mixture for a certain period of time under the action of a quaternary ammonium salt catalyst, then adding a chain extender, a hydroxyl-containing unsaturated monomer, and a tertiary amine to react to obtain a prepolymer solution, which is then mixed with a quaternary ammonium salt containing an unsaturated group in a certain molar ratio and copolymerized under the action of a redox initiator. Although the obtained multifunctional waterborne polyurethane-quaternary ammonium salt polymer is non-toxic or low-toxic, the preparation process is relatively complicated, and the introduced quaternary ammonium salt is a monoquaternary ammonium salt, which has an unsatisfactory antibacterial effect.

[0004] Chinese patent document CN101235130A discloses a cationic water-based polyurethane emulsion and a preparation method thereof. This method comprises prepolymerizing a polyol and an isocyanate, adding a small molecule chain extender composition (to introduce tertiary amine groups), then adding an inorganic acid neutralizer to form a salt, and emulsifying with deionized water to produce a cationic water-based polyurethane emulsion. However, due to the weak cation activity of the tertiary amine groups in the cationic water-based polyurethane, the polyurethane emulsion has poor antibacterial properties, and therefore its application in the field of antibacterial materials is significantly limited. Summary of the Invention

[0005] In view of the deficiencies of the prior art, the object of the present invention is to provide a sulfonium polymer-based antibacterial polyurethane emulsion and a preparation method and application thereof.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for preparing a sulfonium polymer-based antibacterial polyurethane emulsion comprises the following steps:

[0008] S1. Preparation of prepolymer

[0009] First, the sulfonium polymer and the polyol are uniformly mixed to obtain a mixture, and then the mixture and diisocyanate are reacted under the action of a catalyst to obtain a prepolymer.

[0010] In this step, the amount of the sulfonium polymer is 5-10 parts by weight, for example, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, and 10 parts can be selected; the amount of the polyol is 30-40 parts, for example, 30 parts, 31 parts, 32 parts, 33 parts, 34 parts, 35 parts, 36 parts, 37 parts, 38 parts, 39 parts, and 40 parts can be selected; the amount of the diisocyanate is 12-18 parts, for example, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, and 18 parts can be selected; and the amount of the catalyst is 0.5-1 part, for example, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, and 1 part can be selected, but the values ​​listed are not limited thereto, and other values ​​not listed within the numerical range are also applicable.

[0011] In the technical solution disclosed in the present invention, the preparation method of the sulfonium polymer is as follows:

[0012] (1) Add polyethylene glycol monomethyl ether, tetrahydrofuran, and boron trifluoride etherate (BF3·Et2O) to dichloromethane and stir evenly in an ice-water bath. Then add allyl glycidyl ether dropwise and stir at room temperature for 4-8 hours. Then add distilled water to terminate the reaction. Concentrate the mixture by rotary evaporation, precipitate, and dry to obtain a colorless viscous liquid.

[0013] (2) Add a colorless viscous liquid, butanethiol, and dimethyl benzoate (DMPA) to the organic solvent DMF, introduce nitrogen to expel the air, seal the container, and react under ultraviolet light for 24-48 hours. After the reaction is completed, precipitate, and dry to obtain a light yellow viscous liquid;

[0014] (3) Dissolve the light yellow viscous liquid in formic acid, then add epichlorohydrin, and heat and stir under nitrogen protection to react. After the reaction is completed, precipitate the obtained crude product, dialyze, and freeze-dry to obtain a sulfonium polymer.

[0015] The specific synthesis process of the sulfonium polymer is as follows:

[0016]

[0017] Specifically, in step (1), the molar ratio of polyethylene glycol monomethyl ether, tetrahydrofuran, allyl glycidyl ether and boron trifluoride ethyl ether is 1:60:10-40:0.5-1.

[0018] Specifically, the molar ratio of allyl glycidyl ether, butanethiol, benzoin dimethyl ether, and epichlorohydrin is 1:0.8-1.2:0.02-0.05:0.5-1.5.

[0019] Specifically, in step (3), the temperature of the heating and stirring reaction is 35-50°C, for example, 35°C, 40°C, 45°C, or 50°C can be selected; the time of the heating and stirring reaction is 18-36h, for example, 18h, 24h, 30h, or 36h can be selected; the speed of the heating and stirring reaction is 600-800r / min, for example, 600r / min, 650r / min, 700r / min, 750r / min, or 800r / min can be selected, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0020] In the technical solution disclosed in the present invention, the polyol is selected from polyether diol, polyester diol or polyethylene glycol.

[0021] In the technical solution disclosed in the present invention, the diisocyanate is selected from isophorone diisocyanate, hexamethylene diisocyanate or toluene diisocyanate.

[0022] In the technical solution disclosed in the present invention, the catalyst is selected from stannous octoate, dibutyltin dilaurate or dibutyltin oxide.

[0023] In this step, the reaction temperature is 80-90°C, for example, 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C, and 90°C can be selected; the reaction time is 2-4h, for example, 2h, 2.5h, 3h, 3.5h, and 4h can be selected, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0024] S2. Preparation of polyurethane prepolymer

[0025] A hydrophilic chain extender is added to the prepolymer obtained in step S1 to continue the reaction, and then the viscosity of the system is adjusted with acetone to obtain a polyurethane prepolymer.

[0026] In this step, the amount of the hydrophilic chain extender is 3-5 parts, for example, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts can be selected, but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0027] In the technical solution disclosed in the present invention, the hydrophilic chain extender is selected from dimethylol propionic acid and / or dimethylol butyric acid.

[0028] In this step, the temperature for continuing the reaction is 80-90°C, for example, 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C, and 90°C can be selected; the time for continuing the reaction is 1-2h, for example, 1h, 1.5h, and 2h can be selected, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0029] In this step, acetone is added to dilute the system to a solid content of 40-80%.

[0030] S3. Preparation of sulfonium polymer-based antibacterial polyurethane emulsion

[0031] A neutralizing agent, triethylamine, is added to the polyurethane prepolymer and stirred for 30-45 minutes, followed by addition of deionized water for dispersion, and acetone is removed by rotary evaporation to obtain a sulfonium polymer-based antibacterial polyurethane emulsion.

[0032] In this step, the number of parts of the neutralizing agent triethylamine is 1.5-2 parts, for example, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, and 2 parts can be selected; the number of parts of deionized water is 60-80 parts, for example, 60 parts, 65 parts, 70 parts, 75 parts, and 80 parts can be selected; but the values ​​are not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0033] In a second aspect, the present invention provides a sulfonium polymer-based antibacterial polyurethane emulsion prepared by the above preparation method.

[0034] In a third aspect, the present invention further provides the use of the sulfonium polymer-based antibacterial polyurethane emulsion in antibacterial materials.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) The present invention first blends a sulfonium polymer and a polyol, then generates a prepolymer with a diisocyanate monomer, introduces the sulfonium polymer into the main chain of the polyurethane, and then forms an aqueous polyurethane emulsion through chain extension, neutralization, dispersion and emulsification. The sulfonium polymer-based antibacterial polyurethane emulsion prepared by the present invention has excellent antibacterial properties, mechanical properties and biocompatibility.

[0037] (2) The sulfonium polymer provided by the present invention first prepares an amphiphilic polymer by cationic ring-opening polymerization, introduces a double bond into the side chain of the hydrophobic segment, then introduces sulfur element by ultraviolet click reaction of thiol-double bond, and then opens the epoxy group under acidic conditions to obtain sulfur cations to obtain an amphiphilic sulfonium polymer. The sulfonium polymer prepared by the present invention contains hydroxyl groups and can undergo cross-linking reaction with isocyanate groups. Compared with adding the sulfonium polymer during the chain extension process, the present invention first mixes the sulfonium polymer and polyol, and then reacts with diisocyanate. By introducing the sulfonium polymer into the main chain of the polyurethane, it has more lasting antibacterial properties and better mechanical properties. In addition, the sulfonium polymer prepared by the present invention exhibits better biocompatibility than amine compounds. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is the infrared spectrum of the sulfonium polymer prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0039] The present invention is further described in detail below through specific preferred embodiments, but the present invention is not limited to the following embodiments.

[0040] It should be noted that, unless otherwise specified, all chemical reagents involved in the present invention were purchased through commercial channels.

[0041] Example 1

[0042] A method for preparing a sulfonium polymer-based antibacterial polyurethane emulsion comprises the following steps:

[0043] S1. 5 parts of a sulfonium polymer and 30 parts of polyethylene glycol propylene glycol ether (number average molecular weight of 4000) were uniformly mixed to obtain a mixture. The mixture, 12 parts of isophorone diisocyanate, and 0.5 parts of a catalyst, stannous octoate, were then added to a reactor, and the mixture was reacted at 80° C. for 4 hours to obtain a prepolymer.

[0044] Wherein, the preparation method of the sulfonium polymer is as follows:

[0045] (1) 0.5 mmol of polyethylene glycol monomethyl ether (number average molecular weight of 2000), 30 mmol of tetrahydrofuran, and 0.25 mmol of boron trifluoride ether were added to 3 mL of dichloromethane and stirred in an ice-water bath for 20 min. Then, 5 mmol of allyl glycidyl ether was added dropwise and stirred at room temperature for 6 h. Then, distilled water was added to terminate the reaction. The mixture was concentrated by rotary evaporation and precipitated with cold petroleum ether. After drying, a colorless viscous liquid was obtained.

[0046] (2) The above colorless viscous liquid, 5 mmol of butanethiol and 0.1 mmol of benzoin dimethyl ether were added to 5 mL of organic solvent DMF, nitrogen was introduced to expel the air, and the mixture was sealed and reacted under ultraviolet light for 36 hours. After the reaction was completed, the solution was slowly added dropwise to cold petroleum ether for precipitation, and dried to obtain a light yellow viscous liquid;

[0047] (3) The above-mentioned light yellow viscous liquid was dissolved in formic acid to a concentration of 60 mg / mL, and then 5 mmol of epichlorohydrin was added. The mixture was stirred at 37°C for 24 h under nitrogen protection and the stirring speed was 600 r / min. After the reaction was completed, the crude product was precipitated in ice petroleum ether, then dialyzed in deionized water for 48 h, and then freeze-dried to obtain a sulfonium polymer.

[0048] S2, adding 3 parts of dimethylolpropionic acid (a hydrophilic chain extender) to the prepolymer obtained in step S1, continuing the reaction at 80° C. for 1 hour, and then adding acetone to dilute the system to a solid content of 40%, to obtain a polyurethane prepolymer;

[0049] S3. Add 1.5 parts of triethylamine as a neutralizing agent to the polyurethane prepolymer obtained in step S2, stir for 30 minutes, then add 60 parts of deionized water, disperse in a high-speed disperser at 2000 rpm for 40 minutes, and remove acetone by rotary evaporation to obtain a sulfonium polymer-based antibacterial polyurethane emulsion.

[0050] The infrared spectrum of the sulfonium polymer prepared in step S1 of this embodiment is as follows: Figure 1 As shown in the figure, the red curve is the infrared spectrum of the colorless viscous liquid prepared in step (1), at 1645cm -1 The black curve in the figure is the infrared spectrum of the light yellow viscous liquid prepared in step (2). The black curve has a peak at 1645cm -1 The disappearance of the characteristic peak of the carbon-carbon double bond at 1720 cm indicates that the carbon-carbon double bond reacted with the thiol group, indicating that the grafting reaction proceeded smoothly. The blue curve in the figure is the infrared spectrum of the sulfonium polymer prepared in step (3). The blue curve is at 1720 cm -1 The carbonyl characteristic peak appeared at , indicating that the sulfonium polymer was successfully prepared.

[0051] Example 2

[0052] A method for preparing a sulfonium polymer-based antibacterial polyurethane emulsion comprises the following steps:

[0053] S1. 10 parts of a sulfonium polymer and 40 parts of polyethylene glycol propylene glycol ether (number average molecular weight of 4000) were mixed to obtain a mixture, and then the mixture, 18 parts of isophorone diisocyanate, and 1 part of a catalyst, stannous octoate, were added to a reactor, and the mixture was reacted at 90° C. for 2 hours to obtain a prepolymer;

[0054] Wherein, the preparation method of the sulfonium polymer is as follows:

[0055] (1) 0.5 mmol of polyethylene glycol monomethyl ether (number average molecular weight of 2000), 30 mmol of tetrahydrofuran, and 0.25 mmol of boron trifluoride ether were added to 3 mL of dichloromethane and stirred in an ice-water bath for 20 min. 10 mmol of allyl glycidyl ether was then added dropwise and stirred at room temperature for 6 h. Distilled water was then added to terminate the reaction. The mixture was concentrated by rotary evaporation and precipitated with cold petroleum ether. The mixture was dried to obtain a colorless viscous liquid.

[0056] (2) The above colorless viscous liquid, 10 mmol of butanethiol and 0.2 mmol of benzoin dimethyl ether were added to 5 mL of organic solvent DMF, nitrogen was introduced to expel the air, and the mixture was sealed and reacted under ultraviolet light for 36 hours. After the reaction was completed, the solution was slowly added dropwise to cold petroleum ether for precipitation, and dried to obtain a light yellow viscous liquid;

[0057] (3) The above-mentioned light yellow viscous liquid was dissolved in formic acid to a concentration of 60 mg / mL, and then 10 mmol of epichlorohydrin was added. The mixture was stirred at 37°C for 24 h under nitrogen protection and the stirring speed was 600 r / min. After the reaction was completed, the crude product was precipitated in ice petroleum ether, then dialyzed in deionized water for 48 h, and then freeze-dried to obtain a sulfonium polymer.

[0058] S2, adding 5 parts of dimethylolpropionic acid (a hydrophilic chain extender) to the prepolymer obtained in step S1, continuing the reaction at 80° C. for 1 hour, and then adding acetone to dilute the system to a solid content of 60%, to obtain a polyurethane prepolymer;

[0059] S3, adding 2 parts of a neutralizing agent, triethylamine, to the polyurethane prepolymer obtained in step S2, stirring for 30 minutes, then adding 80 parts of deionized water, dispersing the mixture at 2000 rpm for 40 minutes using a high-speed disperser, and removing acetone by rotary evaporation to obtain a sulfonium polymer-based antibacterial polyurethane emulsion.

[0060] Example 3

[0061] A method for preparing a sulfonium polymer-based antibacterial polyurethane emulsion comprises the following steps:

[0062] S1. 8 parts of a sulfonium polymer and 35 parts of polyethylene glycol propylene glycol ether (number average molecular weight of 4000) were uniformly mixed to obtain a mixture. The mixture, 15 parts of isophorone diisocyanate, and 0.8 parts of a catalyst, stannous octoate, were then added to a reactor, and the mixture was reacted at 90° C. for 2 hours to obtain a prepolymer.

[0063] Wherein, the preparation method of the sulfonium polymer is as follows:

[0064] (1) 0.5 mmol polyethylene glycol monomethyl ether (number average molecular weight 2000), 30 mmol tetrahydrofuran, and 0.25 mmol boron trifluoride ether were added to 3 mL dichloromethane and stirred in an ice-water bath for 20 min. 15 mmol allyl glycidyl ether was then added dropwise and stirred at room temperature for 6 h. Distilled water was then added to terminate the reaction. The mixture was concentrated by rotary evaporation and precipitated with cold petroleum ether. The mixture was dried to obtain a colorless viscous liquid.

[0065] (2) The above colorless viscous liquid, 15 mmol of butanethiol and 0.3 mmol of benzoin dimethyl ether were added to 5 mL of organic solvent DMF, nitrogen was introduced to expel the air, and the mixture was sealed and reacted under ultraviolet light for 36 hours. After the reaction was completed, the solution was slowly added dropwise to cold petroleum ether for precipitation, and dried to obtain a light yellow viscous liquid;

[0066] (3) The above-mentioned light yellow viscous liquid was dissolved in formic acid to a concentration of 60 mg / mL, and then 15 mmol of epichlorohydrin was added. The mixture was stirred at 37°C for 24 h under nitrogen protection and the stirring speed was 600 r / min. After the reaction was completed, the crude product was precipitated in ice petroleum ether, then dialyzed in deionized water for 48 h, and then freeze-dried to obtain a sulfonium polymer.

[0067] S2, adding 4 parts of dimethylolpropionic acid, a hydrophilic chain extender, to the prepolymer obtained in step S1, continuing the reaction at 80° C. for 1 hour, and then adding acetone to dilute the system to a solid content of 60%, to obtain a polyurethane prepolymer;

[0068] S3. Add 2 parts of triethylamine, a neutralizing agent, to the polyurethane prepolymer obtained in step S2, and stir for 30 minutes. Then, add 10 parts of deionized water, disperse the mixture in a high-speed disperser at 2000 rpm for 40 minutes, and remove acetone by rotary evaporation to obtain a sulfonium polymer-based antibacterial polyurethane emulsion.

[0069] Example 4

[0070] A method for preparing a sulfonium polymer-based antibacterial polyurethane emulsion comprises the following steps:

[0071] S1. 6 parts of a sulfonium polymer and 32 parts of polyethylene propylene glycol phthalate (number average molecular weight of 2000) were uniformly mixed to obtain a mixture. The mixture, 15 parts of isophorone diisocyanate, and 0.6 parts of a catalyst, stannous octoate, were then added to a reactor, and the mixture was reacted at 80° C. for 4 hours to obtain a prepolymer.

[0072] Wherein, the preparation method of the sulfonium polymer is as follows:

[0073] (1) 0.5 mmol of polyethylene glycol monomethyl ether (number average molecular weight of 2000), 30 mmol of tetrahydrofuran, and 0.25 mmol of boron trifluoride ether were added to 3 mL of dichloromethane and stirred in an ice-water bath for 20 min. 20 mmol of allyl glycidyl ether was then added dropwise and stirred at room temperature for 6 h. Distilled water was then added to terminate the reaction. The mixture was concentrated by rotary evaporation and precipitated with cold petroleum ether. The mixture was dried to obtain a colorless viscous liquid.

[0074] (2) The above colorless viscous liquid, 20 mmol of butanethiol and 0.4 mmol of benzoin dimethyl ether were added to 5 mL of organic solvent DMF, nitrogen was introduced to expel the air, and the mixture was sealed and reacted under ultraviolet light for 36 hours. After the reaction was completed, the solution was slowly added dropwise to cold petroleum ether for precipitation, and dried to obtain a light yellow viscous liquid;

[0075] (3) The above-mentioned light yellow viscous liquid was dissolved in formic acid to a concentration of 60 mg / mL, and then 20 mmol of epichlorohydrin was added. The mixture was stirred at 37°C for 24 h under nitrogen protection and the stirring speed was 600 r / min. After the reaction was completed, the crude product was precipitated in ice petroleum ether, then dialyzed in deionized water for 48 h, and then freeze-dried to obtain a sulfonium polymer;

[0076] S2, adding 5 parts of dimethylolpropionic acid (a hydrophilic chain extender) to the prepolymer obtained in step S1, continuing the reaction at 80° C. for 1 hour, and then adding acetone to dilute the system to a solid content of 60%, to obtain a polyurethane prepolymer;

[0077] S3. Add 2 parts of triethylamine as a neutralizing agent to the polyurethane prepolymer obtained in step S2, stir for 30 minutes, then add 65 parts of deionized water, disperse in a high-speed disperser at 2000 rpm for 40 minutes, and remove acetone by rotary evaporation to obtain a sulfonium polymer-based antibacterial polyurethane emulsion.

[0078] Comparative Example 1

[0079] A method for preparing a polyurethane emulsion comprises the following steps:

[0080] S1. Add 35 parts of polyethylene glycol propylene glycol ether (number average molecular weight 4000), 15 parts of isophorone diisocyanate and 0.8 parts of stannous octoate as a catalyst into a reactor, and react at 90° C. for 2 hours to obtain a prepolymer;

[0081] S2, adding 4 parts of dimethylolpropionic acid, a hydrophilic chain extender, to the prepolymer obtained in step S1, continuing the reaction at 80° C. for 1 hour, and then adding acetone to dilute the system to a solid content of 60%, to obtain a polyurethane prepolymer;

[0082] S3, adding 2 parts of a neutralizing agent, triethylamine, to the polyurethane prepolymer obtained in step S2, stirring for 30 minutes, then adding 10 parts of deionized water, dispersing the mixture at 2000 rpm in a high-speed disperser for 40 minutes, and removing acetone by rotary evaporation to obtain a polyurethane emulsion.

[0083] Comparing Comparative Example 1 with Example 3, no sulfonium polymer was added.

[0084] Comparative Example 2

[0085] A method for preparing a polyurethane emulsion comprises the following steps:

[0086] S1. Add 35 parts of polyethylene glycol propylene glycol ether (number average molecular weight 4000), 15 parts of isophorone diisocyanate and 0.8 parts of stannous octoate as a catalyst into a reactor, and react at 90° C. for 2 hours to obtain a prepolymer;

[0087] S2, adding 4 parts of dimethylolpropionic acid (a hydrophilic chain extender) and 8 parts of sulfonium polymer to the prepolymer obtained in step S1, continuing the reaction at 80° C. for 1 hour, and then adding acetone to dilute the system to a solid content of 60%, to obtain a polyurethane prepolymer;

[0088] Wherein, the preparation method of the sulfonium polymer is as follows:

[0089] (1) 0.5 mmol polyethylene glycol monomethyl ether (number average molecular weight 2000), 30 mmol tetrahydrofuran, and 0.25 mmol boron trifluoride ether were added to 3 mL dichloromethane and stirred in an ice-water bath for 20 min. 15 mmol allyl glycidyl ether was then added dropwise and stirred at room temperature for 6 h. Distilled water was then added to terminate the reaction. The mixture was concentrated by rotary evaporation and precipitated with cold petroleum ether. The mixture was dried to obtain a colorless viscous liquid.

[0090] (2) The above colorless viscous liquid, 15 mmol of butanethiol and 0.3 mmol of benzoin dimethyl ether were added to 5 mL of organic solvent DMF, nitrogen was introduced to expel the air, and the mixture was sealed and reacted under ultraviolet light for 36 hours. After the reaction was completed, the solution was slowly added dropwise to cold petroleum ether for precipitation, and dried to obtain a light yellow viscous liquid;

[0091] (3) The above-mentioned light yellow viscous liquid was dissolved in formic acid to a concentration of 60 mg / mL, and then 15 mmol of epichlorohydrin was added. The mixture was stirred at 37°C for 24 h under nitrogen protection and the stirring speed was 600 r / min. After the reaction was completed, the crude product was precipitated in ice petroleum ether, then dialyzed in deionized water for 48 h, and then freeze-dried to obtain a sulfonium polymer.

[0092] S3, adding 2 parts of a neutralizing agent, triethylamine, to the polyurethane prepolymer obtained in step S2, stirring for 30 minutes, then adding 10 parts of deionized water, dispersing the mixture at 2000 rpm in a high-speed disperser for 40 minutes, and removing acetone by rotary evaporation to obtain a polyurethane emulsion.

[0093] Compared with Example 3, Comparative Example 2 adds the sulfonium polymer during the prepolymer chain extension stage.

[0094] Comparative Example 3

[0095] A method for preparing a polyurethane emulsion comprises the following steps:

[0096] S1. Add 35 parts of polyethylene glycol propylene glycol ether (number average molecular weight 4000), 15 parts of isophorone diisocyanate and 0.8 parts of stannous octoate as a catalyst into a reactor, and react at 90° C. for 2 hours to obtain a prepolymer;

[0097] S2, adding 4 parts of dimethylolpropionic acid (a hydrophilic chain extender) and 8 parts of thiosemicarbazide to the prepolymer obtained in step S1, continuing the reaction at 80° C. for 1 hour, and then adding acetone to dilute the system to a solid content of 60%, to obtain a polyurethane prepolymer;

[0098] S3, adding 2 parts of a neutralizing agent, triethylamine, to the polyurethane prepolymer obtained in step S2, stirring for 30 minutes, then adding 10 parts of deionized water, dispersing the mixture at 2000 rpm in a high-speed disperser for 40 minutes, and removing acetone by rotary evaporation to obtain a polyurethane emulsion.

[0099] Comparative Example 3 adds thiosemicarbazide during the prepolymer chain extension stage.

[0100] The performance test of the polyurethane emulsions prepared in Examples 1-4 and Comparative Examples 1-3 was carried out in the following steps:

[0101] The polyurethane emulsions prepared in Examples 1-4 and Comparative Examples 1-3 were evenly spread onto a polytetrafluoroethylene sheet and cast into films. The films were then dried at room temperature and then dried in a 70°C oven for 10 hours to obtain polyurethane coatings with a thickness of 0.2±0.05 mm. The antibacterial rate was tested in accordance with the standards of "GB / T 20944-2007, Textiles - Evaluation of Antibacterial Properties." The strains used in the tests were Staphylococcus aureus USA300 and Escherichia coli ATCC25922.

[0102] Washing resistance test method: Use a phosphate-free ECE standard synthetic detergent to prepare a 2g / L washing solution. Immerse the sample in the washing solution and soak it in a water bath at 25±3℃ for 10 minutes. Rinse it thoroughly with distilled water and dry it. This is counted as one wash. After washing it 50 times, test the antibacterial performance again. The test results are shown in Table 1.

[0103] Table 1 Antibacterial performance test results

[0104]

[0105] Note: “ / ” indicates no obvious antibacterial effect.

[0106] Biocompatibility testing:

[0107] The cytotoxicity experiment was conducted by CCK-8 method. The membranes prepared in Examples 1-4 and Comparative Examples 1-3 were immersed in 0.9% saline at 37°C for 24 h. L929 cells were cultured in vitro and cell suspensions were prepared. 1×10 4 Cells / 100 μL were inoculated into a 96-well plate, with 3 replicates per group. The cells were incubated in a 37°C incubator for 24 hours. The extract was added to the surface of adherent L929 mouse fibroblasts. After 24 hours of culture, the cell culture medium was removed, and 10 μL of CCK-8 solution and 90 μL of culture medium were added to the cells. After 2 hours of culture in a biological incubator, the OD value at 450 nm was measured. The blank group contained culture medium and CCK-8 solution but no cells. The positive control group was added with cell culture medium only without sample. The cell survival rate was calculated using the following formula.

[0108] Cell viability (%) = (OD 样品 -OD 空白 ) / (OD 阳性对照 -OD 空白 ) × 100%

[0109] The test results are shown in Table 2.

[0110] Table 2 Biocompatibility test results

[0111]

[0112] As can be seen from Table 2, compared with Comparative Example 3, the sulfonium polymer prepared in the embodiment of the present invention exhibits better biocompatibility than the amine compound.

[0113] Mechanical properties test: The polyurethane emulsions prepared in Examples 1-4 and Comparative Examples 1-2 were poured into a mold and dried at 70°C for 24 hours to prepare film specimens. The tensile properties were tested according to the national standard GB / T 8949-2008. The test results are shown in Table 3.

[0114] Table 3 Mechanical properties test results

[0115]

[0116] As can be seen from Table 3, compared with Comparative Example 2 in which a sulfonium polymer was added during the chain extension process, the sulfonium polymer-based antibacterial polyurethane emulsion prepared in the embodiment of the present invention has more excellent mechanical properties after film formation.

[0117] Finally, it should be noted that the above embodiments do not limit the present invention in any form. Those skilled in the art will appreciate that modifications and improvements can be made based on the present invention. Therefore, any modifications or improvements made without departing from the spirit of the present invention are intended to fall within the scope of protection claimed in the present invention.

Claims

1. A method for preparing a sulfonium polymer-based antibacterial polyurethane emulsion, characterized in that: The steps include: S1. First, the sulfonium polymer and the polyol are uniformly mixed to obtain a mixture, and then the mixture and the diisocyanate are reacted in the presence of a catalyst to obtain a prepolymer; S2, adding a hydrophilic chain extender to the prepolymer obtained in step S1 to continue the reaction, and then adjusting the viscosity of the system with acetone to obtain a polyurethane prepolymer; S3, adding a neutralizing agent triethylamine to the polyurethane prepolymer obtained in step S2 and stirring for 30-45 minutes, then adding deionized water for dispersion, and removing acetone by rotary evaporation to obtain a sulfonium polymer-based antibacterial polyurethane emulsion; In parts by weight, the sulfonium polymer is 5-10 parts, the polyol is 30-40 parts, the diisocyanate is 12-18 parts, the catalyst is 0.5-1 part, the hydrophilic chain extender is 3-5 parts, the neutralizing agent triethylamine is 1.5-2 parts, and the deionized water is 60-80 parts; Wherein, the preparation method of the sulfonium polymer is as follows: (1) Add polyethylene glycol monomethyl ether, tetrahydrofuran, and boron trifluoride ether to dichloromethane, stir evenly in an ice-water bath, then add allyl glycidyl ether dropwise, stir at room temperature for 4-8 hours, then add distilled water to terminate the reaction, concentrate the mixture by rotary evaporation, precipitate, and dry to obtain a colorless viscous liquid; (2) Add a colorless viscous liquid, butanethiol, and dimethyl benzoate to an organic solvent, DMF, introduce nitrogen to expel the air, seal, and react under ultraviolet light for 24-48 hours. After the reaction is complete, precipitate, and dry to obtain a light yellow viscous liquid. (3) Dissolve the light yellow viscous liquid in formic acid, then add epichlorohydrin, and heat and stir under nitrogen protection to react. After the reaction is completed, precipitate the obtained crude product, dialyze, and freeze-dry to obtain a sulfonium polymer.

2. The preparation method according to claim 1, characterized in that In step (1), the molar ratio of polyethylene glycol monomethyl ether, tetrahydrofuran, allyl glycidyl ether and boron trifluoride ethyl ether is 1:60:10-40:0.5-1.

3. The preparation method according to claim 1, characterized in that The molar ratio of allyl glycidyl ether, butanethiol, benzoin dimethyl ether and epichlorohydrin is 1:0.8-1.2:0.02-0.05:0.5-1.

5.

4. The preparation method according to claim 1, characterized in that In step (3), the temperature of the heating and stirring reaction is 35-50° C., the time of the heating and stirring reaction is 18-36 h, and the speed of the heating and stirring reaction is 600-800 r / min.

5. The preparation method according to claim 1, characterized in that In step S1, the polyol is selected from polyether diol or polyester diol; the diisocyanate is selected from isophorone diisocyanate, hexamethylene diisocyanate or toluene diisocyanate; and the catalyst is selected from stannous octoate, dibutyltin dilaurate or dibutyltin oxide.

6. The preparation method according to claim 1, characterized in that In step S1, the reaction temperature is 80-90° C. and the reaction time is 2-4 h.

7. The preparation method according to claim 1, characterized in that In step S2, the hydrophilic chain extender is selected from dimethylol propionic acid and / or dimethylol butyric acid.

8. The sulfonium polymer-based antibacterial polyurethane emulsion prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the sulfonium polymer-based antibacterial polyurethane emulsion according to claim 8 in the preparation of antibacterial materials.

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