Antibacterial styrene-acrylic emulsion containing sulfonium polymer and preparation method of antibacterial styrene-acrylic emulsion

Abstract

The invention relates to the technical field of polymer emulsion preparation, and particularly discloses an antibacterial styrene-acrylic emulsion containing a sulfonium polymer and a preparation method thereof.According to the sulfonium polymer provided by the invention, an amphiphilic polymer is prepared through cation ring opening polymerization, double bonds are introduced into a side chain of a hydrophobic chain segment, and then the amphiphilic polymer is prepared; the preparation method comprises the following steps: introducing sulfur element through sulfydryl-double bond ultraviolet click reaction, and performing ring opening on an epoxy group under an acidic condition to obtain sulfur positive ions, thereby obtaining the amphiphilic sulfonium polymer. The prepared sulfonium polymer can be subjected to cross-linking reaction with an active group (carboxyl) in a styrene-acrylic emulsion, cannot dissolve out a matrix, and can be used for preparing the amphiphilic sulfonium polymer. Therefore, the styrene-acrylic emulsion is endowed with lasting antibacterial performance; the sulfonium polymer is bonded into a polymer chain of the styrene-acrylic emulsion through chemical action, the sulfonium polymer contains a polyether structure and can play a role in internal emulsification, styrene and acrylate monomers can be polymerized to form the styrene-acrylic emulsion with stable characters, and the styrene-acrylic emulsion has excellent freeze-thaw stability.

Description

Technical Field

[0001] The invention relates to the technical field of polymer emulsion preparation, and in particular to an antibacterial styrene-acrylic emulsion containing a sulfonium polymer and a preparation method thereof. Background Art

[0002] Styrene acrylic emulsion is a water-based emulsion formed by copolymerization of styrene and acrylate monomers. It is widely used in coatings, adhesives, textiles, papermaking and other fields. Its excellent film-forming properties, water resistance and adhesion make it an ideal choice for many industrial products. However, although styrene acrylic emulsion has outstanding physical properties, its antibacterial properties are obviously insufficient. Since styrene acrylic emulsion itself does not have antibacterial activity, it is easy to breed bacteria, mold and other microorganisms when used in humid or microorganism-rich environments, resulting in mildew spots, discoloration and even degradation on the surface of the material, affecting the service life and appearance quality of the product.

[0003] At present, commercially available styrene acrylic emulsion coatings mainly obtain their antibacterial properties by adding inorganic antibacterial agents and organic small molecule antibacterial agents. For example, Chinese patent document CN118931266A discloses a green antibacterial and virus-removing coating and its preparation method, which comprises the following raw materials in parts by weight: 200-230 parts of styrene acrylic emulsion, 30-40 parts of composite fillers, 30-40 parts of titanium dioxide, 200-250 parts of deionized water, 3-5 parts of alcohol ester 12, 3-5 parts of dispersant, 2-4 parts of defoaming agent, 5-10 parts of antibacterial agent, 3-5 parts of wetting agent and 3-6 parts of thickener. The above patent uses styrene acrylic emulsion as the base material, and improves the overall performance of the coating by adding antibacterial agents, composite fillers, titanium dioxide, alcohol ester 12 and other additives, but the prepared coating does not have lasting antibacterial properties.

[0004] In addition, the existing styrene acrylic emulsion and its coating have the disadvantage of poor freeze-thaw resistance because they use water as the dispersion medium. That is, during transportation and storage in a low-temperature environment, the product often deteriorates because it freezes and thaws and solidifies into blocks and cannot restore its fluidity, thus limiting its scope of use. Summary of the invention

[0005] In view of the deficiencies of the prior art, the object of the present invention is to provide an antibacterial styrene acrylic emulsion containing a sulfonium polymer and a preparation method thereof.

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

[0007] A method for preparing an antibacterial styrene-acrylic emulsion containing a sulfonium polymer comprises the following steps:

[0008] S1. Preparation of pre-emulsion

[0009] The emulsifier and the pH adjuster are added into deionized water and mixed evenly, and then styrene, butyl acrylate and acrylic acid are added thereto for pre-emulsification to obtain a pre-emulsified liquid.

[0010] In this step, the amount of the emulsifier 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 pH adjuster is 1-3 parts, for example, 1 part, 1.5 parts, 2 parts, 2.5 parts, and 3 parts can be selected; the amount of deionized water is 100-150 parts, for example, 100 parts, 110 parts, 120 parts, 130 parts, 140 parts, and 150 parts can be selected; the amount of styrene is 20-25 parts, for example, The number of parts can be selected from 20, 21, 22, 23, 24, and 25 parts; the number of parts of butyl acrylate is 20-30 parts, for example, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, and 30 parts can be selected; the number of parts of acrylic acid is 8-12 parts, for example, 8, 9, 10, 11, and 12 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.

[0011] In some embodiments of the present invention, the emulsifier is selected from sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate or Tween 80.

[0012] In some embodiments of the present invention, the pH adjuster is selected from sodium carbonate, sodium bicarbonate, sodium dihydrogen phosphate or potassium dihydrogen phosphate.

[0013] In this step, the pre-emulsification time is 30-90 min, for example, 30 min, 40 min, 45 min, 50 min, 60 min, 70 min, 75 min, 80 min, 90 min can be selected, but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0014] S2. Preparation of antibacterial styrene-acrylic emulsion containing sulfonium polymer

[0015] Under stirring, the pre-emulsion obtained in step S1 is heated to 65-75°C, 1 / 3-1 / 2 of the initiator aqueous solution is added dropwise, and the reaction is carried out for 1-3 hours. The temperature is then raised to 80-85°C, and the sulfonium polymer and the remaining initiator aqueous solution are added. The reaction is continued for 2-4 hours, cooled to room temperature, and filtered to obtain an antibacterial styrene-acrylic emulsion containing the sulfonium polymer.

[0016] In this step, the amount of the initiator aqueous solution is 20-30 parts by weight, for example, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, and 30 parts can be selected; the amount of the sulfonium polymer is 10-15 parts, for example, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, and 15 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.

[0017] In some embodiments of the present invention, the mass fraction of the initiator aqueous solution is 10-30%, for example, 10%, 15%, 20%, 25%, 30% can be selected, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0018] More specifically, the initiator is selected from potassium persulfate, ammonium persulfate or sodium persulfate.

[0019] In this step, the preparation method of the sulfonium polymer is as follows:

[0020] (1) Polyethylene glycol monomethyl ether, tetrahydrofuran, boron trifluoride ether (BF 3 ·Et 2 O) was added to dichloromethane, stirred evenly under an ice-water bath, then allyl glycidyl ether was added dropwise, stirred at room temperature for 4-8h, then distilled water was added to terminate the reaction, the mixed system was concentrated by rotary evaporation, precipitated and dried to obtain a colorless viscous liquid;

[0021] (2) adding a colorless viscous liquid, butanethiol and dimethyl benzoate (DMPA) to an organic solvent DMF, introducing nitrogen to expel the air, sealing the mixture and reacting it under ultraviolet light for 24-48 hours. After the reaction is completed, the mixture is precipitated and dried to obtain a light yellow viscous liquid;

[0022] (3) The light yellow viscous liquid is dissolved in formic acid, and then epichlorohydrin is added, and the mixture is heated and stirred under nitrogen protection to react. After the reaction is completed, the obtained crude product is precipitated, dialyzed, and freeze-dried to obtain a sulfonium polymer.

[0023] The specific synthesis process route of the sulfonium polymer is as follows:

[0024]

[0025] 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.

[0026] 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.

[0027] 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 the values ​​are not limited to the values ​​listed, and other values ​​not listed within the numerical range are also applicable.

[0028] The present invention also provides an antibacterial styrene-acrylic emulsion of a sulfonium-containing polymer prepared by the above preparation method.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) The present invention introduces sulfonium polymer into styrene-acrylic emulsion, so that the styrene-acrylic emulsion has excellent antibacterial property and freeze-thaw stability.

[0031] (2) The sulfonium polymer provided by the present invention is first prepared as an amphiphilic polymer by cationic ring-opening polymerization, a double bond is introduced into the side chain of the hydrophobic segment, and then the sulfur element is introduced by ultraviolet click reaction of thiol-double bond, and then the epoxy group is opened under acidic conditions to obtain sulfur cations to obtain an amphiphilic sulfonium polymer. The sulfonium polymer prepared by the present invention can undergo a cross-linking reaction with the active group (carboxyl group) in the styrene-acrylic emulsion and will not dissolve out of the matrix, thereby giving the styrene-acrylic emulsion a long-lasting antibacterial property.

[0032] (3) The present invention bonds the sulfonium polymer to the polymer chain of the styrene-acrylic emulsion through chemical action. The sulfonium polymer contains a polyether structure, which can play an internal emulsification role, and can form a styrene-acrylic emulsion with stable properties after polymerization of styrene and acrylate monomers, so that the styrene-acrylic emulsion has excellent freeze-thaw stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is the infrared spectrum of the sulfonium polymer prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below through specific preferred embodiments, but the present invention is not limited to the following embodiments.

[0035] It should be noted that, unless otherwise specified, the chemical reagents involved in the present invention were purchased through commercial channels.

[0036] Example 1

[0037] A method for preparing an antibacterial styrene-acrylic emulsion containing a sulfonium polymer comprises the following steps:

[0038] S1, adding 8 parts of emulsifier sodium dodecyl sulfate and 2 parts of pH regulator sodium carbonate to 100 parts of deionized water, mixing evenly, and then adding 20 parts of styrene, 20 parts of butyl acrylate and 8 parts of acrylic acid thereto for pre-emulsification, the pre-emulsification time is 45 minutes, to obtain a pre-emulsified liquid;

[0039] S2, under stirring, heating the pre-emulsion obtained in step S1 to 70°C, adding 10 parts of a 10 wt% aqueous solution of ammonium persulfate dropwise, reacting for 2 hours, then heating to 85°C, adding 10 parts of a sulfonium polymer and 10 parts of a 10 wt% aqueous solution of ammonium persulfate, continuing the reaction for 3 hours, cooling to room temperature, filtering through a 200 mesh filter, and obtaining an antibacterial styrene-acrylic emulsion containing a sulfonium polymer;

[0040] Wherein, the preparation method of the sulfonium polymer is as follows:

[0041] (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 for 20 min in an ice-water bath, followed by dropwise addition of 5 mmol of allyl glycidyl ether, and stirring at room temperature for 6 h. Distilled water was then added to terminate the reaction, and the mixture was concentrated by rotary evaporation, precipitated with cold petroleum ether, and dried to obtain a colorless viscous liquid;

[0042] (2) The colorless viscous liquid, 5 mmol of butanethiol and 0.1 mmol of dimethyl benzoate were added to 5 mL of DMF, and nitrogen was introduced to expel the air. The mixture was sealed and reacted under ultraviolet light for 36 h. 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.

[0043] (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 reaction was stirred at 37° C. for 24 h under nitrogen protection. The stirring speed of the reaction was 600 r / min. After the reaction was completed, the obtained 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.

[0044] The infrared spectrum of the sulfonium polymer prepared in this example 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 -1The 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 has reacted with the thiol group, indicating that the grafting reaction proceeds smoothly. The blue curve in the figure is the infrared spectrum of the sulfonium polymer prepared in step (3). -1 The carbonyl characteristic peak appeared at , indicating that the sulfonium polymer was successfully prepared.

[0045] Example 2

[0046] A method for preparing an antibacterial styrene-acrylic emulsion containing a sulfonium polymer comprises the following steps:

[0047] S1, adding 10 parts of an emulsifier, sodium lauryl sulfate, and 3 parts of a pH regulator, sodium carbonate, to 150 parts of deionized water, mixing them evenly, and then adding 25 parts of styrene, 30 parts of butyl acrylate, and 12 parts of acrylic acid thereto for pre-emulsification, the pre-emulsification time being 90 minutes, to obtain a pre-emulsified liquid;

[0048] S2. While stirring, the pre-emulsion obtained in step S1 was heated to 75° C., 15 parts of a 10 wt% aqueous solution of ammonium persulfate were added dropwise, and the mixture was reacted for 2 h. The mixture was then heated to 82° C., 15 parts of a sulfonium polymer and 15 parts of a 10 wt% aqueous solution of ammonium persulfate were added, and the reaction was continued for 4 h. The mixture was cooled to room temperature and filtered through a 200-mesh filter to obtain an antibacterial styrene-acrylic emulsion containing a sulfonium polymer.

[0049] Wherein, the preparation method of the sulfonium polymer is as follows:

[0050] (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 for 20 min in an ice-water bath, followed by dropwise addition of 10 mmol of allyl glycidyl ether, and stirring at room temperature for 6 h. Distilled water was then added to terminate the reaction, and the mixture was concentrated by rotary evaporation, precipitated with cold petroleum ether, and dried to obtain a colorless viscous liquid;

[0051] (2) The colorless viscous liquid, 10 mmol of butanethiol and 0.2 mmol of dimethyl benzoate were added to 5 mL of DMF, and nitrogen was introduced to expel the air. The mixture was sealed and reacted under ultraviolet light for 36 h. 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.

[0052] (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 reaction was stirred at 37°C for 24 h under nitrogen protection. The stirring speed was 600 r / min. After the reaction was completed, the obtained 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.

[0053] Example 3

[0054] A method for preparing an antibacterial styrene-acrylic emulsion containing a sulfonium polymer comprises the following steps:

[0055] S1, adding 5 parts of sodium dodecylbenzene sulfonate as an emulsifier and 1 part of sodium bicarbonate as a pH adjuster to 100 parts of deionized water, mixing them evenly, and then adding 20 parts of styrene, 25 parts of butyl acrylate and 10 parts of acrylic acid thereto for pre-emulsification, the pre-emulsification time is 30 minutes, to obtain a pre-emulsified liquid;

[0056] S2. While stirring, the pre-emulsion obtained in step S1 was heated to 65° C., 15 parts of a 10 wt% aqueous solution of ammonium persulfate were added dropwise, and the mixture was reacted for 2 h. The mixture was then heated to 80° C., 12 parts of a sulfonium polymer and 15 parts of a 10 wt% aqueous solution of ammonium persulfate were added, and the reaction was continued for 4 h. The mixture was cooled to room temperature and filtered through a 200-mesh filter to obtain an antibacterial styrene-acrylic emulsion containing a sulfonium polymer.

[0057] Wherein, the preparation method of the sulfonium polymer is as follows:

[0058] (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 for 20 min in an ice-water bath, followed by dropwise addition of 15 mmol of allyl glycidyl ether, and stirring for 6 h at room temperature. Distilled water was then added to terminate the reaction, and the mixture was concentrated by rotary evaporation, precipitated with cold petroleum ether, and dried to obtain a colorless viscous liquid;

[0059] (2) The colorless viscous liquid, 15 mmol of butanethiol and 0.3 mmol of dimethyl benzoate were added to 5 mL of DMF, and nitrogen was introduced to expel air. The mixture was sealed and reacted under ultraviolet light for 36 h. 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.

[0060] (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 reaction was stirred at 37° C. for 24 h under nitrogen protection. The stirring speed of the reaction was 600 r / min. After the reaction was completed, the obtained 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.

[0061] Example 4

[0062] A method for preparing an antibacterial styrene-acrylic emulsion containing a sulfonium polymer comprises the following steps:

[0063] S1, adding 6 parts of emulsifier Tween 80 and 1.5 parts of pH regulator sodium bicarbonate to 120 parts of deionized water, mixing evenly, and then adding 22 parts of styrene, 28 parts of butyl acrylate and 8 parts of acrylic acid thereto for pre-emulsification, the pre-emulsification time is 45 minutes, to obtain a pre-emulsified liquid;

[0064] S2. While stirring, the pre-emulsion obtained in step S1 was heated to 70° C., 10 parts of a 10 wt% aqueous solution of ammonium persulfate were added dropwise, and the mixture was reacted for 2 h. The mixture was then heated to 82° C., 12 parts of a sulfonium polymer and 10 parts of a 10 wt% aqueous solution of ammonium persulfate were added, and the reaction was continued for 4 h. The mixture was cooled to room temperature and filtered through a 200-mesh filter to obtain an antibacterial styrene-acrylic emulsion containing a sulfonium polymer.

[0065] Wherein, the preparation method of the sulfonium polymer is as follows:

[0066] (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 for 20 min in an ice-water bath, followed by dropwise addition of 20 mmol of allyl glycidyl ether, and stirring for 6 h at room temperature. Distilled water was then added to terminate the reaction, and the mixture was concentrated by rotary evaporation, precipitated with cold petroleum ether, and dried to obtain a colorless viscous liquid;

[0067] (2) The colorless viscous liquid, 20 mmol of butanethiol and 0.4 mmol of dimethyl benzoate were added to 5 mL of DMF, and nitrogen was introduced to expel the air. The mixture was sealed and reacted under ultraviolet light for 36 h. 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.

[0068] (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 reaction was stirred at 37° C. for 24 h under nitrogen protection. The stirring speed of the reaction was 600 r / min. After the reaction was completed, the obtained 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.

[0069] Comparative Example 1

[0070] A method for preparing a styrene-acrylic emulsion comprises the following steps:

[0071] S1, adding 10 parts of an emulsifier, sodium lauryl sulfate, and 3 parts of a pH regulator, sodium carbonate, to 150 parts of deionized water, mixing them evenly, and then adding 25 parts of styrene, 30 parts of butyl acrylate, and 12 parts of acrylic acid thereto for pre-emulsification, the pre-emulsification time being 90 minutes, to obtain a pre-emulsified liquid;

[0072] S2. Under stirring, the pre-emulsion obtained in step S1 is heated to 75° C., 15 parts of a 10 wt% aqueous solution of ammonium persulfate are added dropwise, and the reaction is carried out for 2 h. The pre-emulsion is then heated to 82° C., 15 parts of a 10 wt% aqueous solution of ammonium persulfate are added, and the reaction is continued for 4 h. The pre-emulsion is cooled to room temperature and filtered through a 200-mesh filter to obtain a styrene-acrylic emulsion.

[0073] Compared with Example 2, Comparative Example 1 does not add sulfonium polymer.

[0074] Comparative Example 2

[0075] A method for preparing a styrene-acrylic emulsion comprises the following steps:

[0076] S1, adding 10 parts of an emulsifier, sodium lauryl sulfate, and 3 parts of a pH regulator, sodium carbonate, to 150 parts of deionized water, mixing them evenly, and then adding 25 parts of styrene, 30 parts of butyl acrylate, and 12 parts of acrylic acid thereto for pre-emulsification, the pre-emulsification time being 90 minutes, to obtain a pre-emulsified liquid;

[0077] S2. Under stirring, the pre-emulsion obtained in step S1 is heated to 75° C., 15 parts of a 10 wt% aqueous solution of ammonium persulfate are added dropwise, and the reaction is carried out for 2 h. The temperature is then raised to 82° C., 15 parts of dodecyltrimethylammonium chloride and 15 parts of a 10 wt% aqueous solution of ammonium persulfate are added, and the reaction is continued for 4 h. The mixture is cooled to room temperature and filtered through a 200-mesh filter to obtain a styrene-acrylic emulsion.

[0078] Compared with Example 2, Comparative Example 2 uses the commonly used antibacterial agent dodecyltrimethylammonium chloride to replace the sulfonium polymer.

[0079] The performance test of the styrene acrylic emulsion prepared in Examples 1-4 and Comparative Examples 1-2 was carried out, and the specific steps were as follows:

[0080] The styrene acrylic emulsions prepared in Examples 1-4 and Comparative Examples 1-2 were evenly spread on polytetrafluoroethylene plates to form films, then dried at room temperature, and then placed in a 70°C oven for drying for 10 hours to obtain a coating film with a film thickness of 0.2±0.05 mm. The antibacterial rate was tested in accordance with the standard "GB / T 20944-2007, Textiles, Evaluation of Antibacterial Properties"; the strains used in the test were Staphylococcus aureus USA300 and Escherichia coli ATCC25922.

[0081] Washing resistance test method: Use phosphorus-free ECE standard synthetic detergent to prepare 2g / L washing solution, immerse the sample in the washing solution, soak it in a 25±3℃ water bath for 10 minutes, rinse it thoroughly with distilled water, dry it, and record it as one wash. After washing 30 times, test the antibacterial performance again. The test results are shown in Table 1.

[0082] Table 1 Antibacterial performance test results

[0083]

[0084] Note: “ / ” indicates no obvious antibacterial effect.

[0085] Freeze-thaw stability test:

[0086] The test was conducted with reference to GB / T 20623-2006 standard. The styrene acrylic emulsion samples prepared in Examples 1-4 and Comparative Examples 1-2 were placed in a -10°C freezer for 18 hours, taken out, and then placed at 25°C for 6 hours, which was a complete freeze-thaw cycle. The container was opened and the test sample was fully stirred. If there was no lump, coagulation or separation, the freeze-thaw cycle was repeated. The freeze-thaw index increased by 1 for each pass, and the results were expressed in numbers. The larger the number, the better the freeze-thaw stability of the emulsion. The test results are shown in Table 2.

[0087] Table 2 Freeze-thaw stability test results

[0088]

[0089]

[0090] It can be seen from Table 2 that, compared with Comparative Examples 1 and 2, after adding the sulfonium polymer in the embodiment of the present invention, the freeze-thaw stability of the styrene-acrylic emulsion obtained is significantly improved.

[0091] Finally, it should be noted that the above embodiments do not limit the present invention in any form. For those skilled in the art, some modifications and improvements can be made to the present invention. Therefore, any modification or improvement made without departing from the spirit of the present invention belongs to the scope of protection claimed in the present invention.

Claims

1. A method for preparing an antibacterial styrene-acrylic emulsion containing a sulfonium polymer, characterized in that: The steps include: S1, adding an emulsifier and a pH adjuster into deionized water, mixing them evenly, and then adding styrene, butyl acrylate and acrylic acid thereto for pre-emulsification to obtain a pre-emulsified liquid; S2. While stirring, the pre-emulsion obtained in step S1 is heated to 65-75° C., 1 / 3-1 / 2 of the initiator aqueous solution is added dropwise, and the reaction is carried out for 1-3 hours. The temperature is then raised to 80-85° C., the sulfonium polymer and the remaining initiator aqueous solution are added, and the reaction is continued for 2-4 hours. The mixture is cooled to room temperature and filtered to obtain an antibacterial styrene-acrylic emulsion containing the sulfonium polymer; In parts by weight, the emulsifier is 5-10 parts, the pH adjuster is 1-3 parts, the deionized water is 100-150 parts, the styrene is 20-25 parts, the butyl acrylate is 20-30 parts, the acrylic acid is 8-12 parts, the initiator aqueous solution is 20-30 parts, and the sulfonium polymer is 10-15 parts.

2. The preparation method according to claim 1, characterized in that: In step S1, the emulsifier is selected from sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate or Tween 80.

3. The preparation method according to claim 1, characterized in that: In step S1, the pH adjuster is selected from sodium carbonate, sodium bicarbonate, sodium dihydrogen phosphate or potassium dihydrogen phosphate.

4. The preparation method according to claim 1, characterized in that: In step S2, the initiator is selected from potassium persulfate, ammonium persulfate or sodium persulfate.

5. The preparation method according to claim 1, characterized in that: In step S2, the mass fraction of the initiator aqueous solution is 10-30%.

6. The preparation method according to claim 1, characterized in that: In step S2, 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 dropwise add allyl glycidyl ether, 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) adding a colorless viscous liquid, butanethiol and dimethyl benzoate to an organic solvent DMF, introducing nitrogen to expel the air, sealing the mixture and reacting it under ultraviolet light for 24-48 hours. After the reaction is completed, the mixture is precipitated and dried to obtain a light yellow viscous liquid; (3) The light yellow viscous liquid is dissolved in formic acid, and then epichlorohydrin is added, and the mixture is heated and stirred under nitrogen protection to react. After the reaction is completed, the obtained crude product is precipitated, dialyzed, and freeze-dried to obtain a sulfonium polymer.

7. The preparation method according to claim 6, 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.

8. The preparation method according to claim 6, 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.

9. The preparation method according to claim 6, 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 18-36h, and the speed of the heating and stirring reaction is 600-800r / min.

10. The antibacterial styrene-acrylic emulsion of the sulfonium-containing polymer prepared by the preparation method according to any one of claims 1 to 9.

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