Preparation method of acrylic emulsion with PH response antibacterial function

Abstract

The invention provides a preparation method of an acrylic emulsion with a PH response antibacterial function. The preparation method comprises the following steps: adding an emulsifier and water into a reaction kettle; adding a polymerization monomer composition with olefin acid monomers, and adding an initiator for reaction; adding a polymeric monomer composition of a carrier shell, and adding an initiator to react to form a polymer; and adding a neutralizer and a cationic bactericide into the polymer to obtain the acrylic emulsion. Wherein the acrylic high-molecular polymer is prepared from an olefin acid monomer and an acrylate monomer through emulsion polymerization, and the cationic bactericide is coated inside acrylic polymer particles through acid-base neutralization with the olefin acid monomer in the emulsion polymerization process. The growth process of microorganisms such as bacteria on the surfaces of various base layers can change the PH of the surrounding environment to enable the environment to be acidic, so that the cationic bactericide combined with carboxyl on the high-molecular polymer can be slowly released along with the reduction of the PH, and the lasting and effective antibacterial function is achieved.

Description

Technical Field

[0001] The invention relates to the field of acrylic emulsions, and in particular to a method for preparing an acrylic emulsion with pH-responsive antibacterial function. Background Art

[0002] Microorganisms are widely distributed in the environment, and the damage to various materials is ubiquitous. At the same time, various infectious diseases caused by microorganisms have caused great harm to humans. Especially in the rainy season, the humidity in the air is very high, and indoor walls are prone to water accumulation and moisture absorption, providing favorable conditions for the growth of bacteria and mold. Traditional coatings cannot effectively retain substances such as fungicides. Spraying fungicides directly on the surface of the coating can easily cause harm to people living in it.

[0003] In order to keep the bactericide in the coating for a longer time, such as the bactericidal coating shown in CN105348972B, a quaternary ammonium salt type bactericide with a double bond structure is polymerized on the polymer. Although the bactericide polymerized on the polymer chain segment can be stored in the coating for a longer time, the thickness of the coating is generally above the millimeter level. After the bactericide on the surface is consumed, the bactericidal effect will be seriously affected. Although CN117563039A shows the effect of responsive release of bactericide, the release effect is achieved by swelling of the hydrogel in the alkaline environment, which cannot be applied to the coating.

[0004] In summary, it is of great significance to develop and prepare a coating that can retain the bactericide in the coating for a longer period of time and release the bactericide responsively to bacterial adsorption and growth. Summary of the invention

[0005] In view of the shortcomings of the prior art, one of the objects of the present invention is to provide a method for preparing an acrylic emulsion with pH-responsive antibacterial function. The emulsion prepared by the method is used in a coating and can release a bactericide when bacteria are adsorbed and grow, thereby effectively improving the utilization efficiency of the bactericide and reducing the damage to the environment caused by the leakage of the bactericide.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] A preparation method of acrylic emulsion, the preparation method comprising the steps of:

[0008] S1: Add emulsifier and water into the reactor, stir and heat up;

[0009] S2: adding a polymerizable monomer composition A having an olefinic acid monomer and adding an initiator to react;

[0010] S3: After the reaction is completed, the polymerizable monomer composition B of the carrier shell is added, and an initiator is added to react to form a polymer;

[0011] S4: adding a neutralizing agent and a cationic bactericide to the polymer to obtain a target acrylic emulsion.

[0012] The inventors have found that the present invention designs an inner layer polymer with a high carboxyl content (the proportion of carboxyl monomers in conventional emulsion polymerization is less than 10%) and an outer shell structure polymer with a certain hardness during the polymerization process. After the neutralizer is added to the polymer emulsion, the carboxyl groups on the inner layer polymer molecular chains are neutralized, causing the polymer molecular chains to stretch and form latex particles with a hollow structure. The quaternary ammonium salt or quaternary phosphonium salt structure on the cationic bactericide is aggregated inside the latex particles through electrostatic adsorption with the carboxyl groups. When bacteria are adsorbed and grown on the surface of the coating containing the polymer, the acidic substances produced by the bacteria will promote the desorption of the cationic bactericide and the carboxyl groups, thereby releasing the bactericide to achieve an antibacterial effect.

[0013] In one embodiment of the present invention, the heating temperature in S1 is 60-95°C.

[0014] In one embodiment of the present invention, the polymerizable monomer composition A in S2 is composed of one or more of olefinic acid monomers and (meth)acrylate monomers and styrene monomers; preferably, the olefinic acid monomers contain one or more of acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, preferably acrylic acid and / or methacrylic acid; preferably, the mass ratio of the olefinic acid monomers to the polymerizable monomer composition A is 10-50%; preferably, the mass ratio of the polymerizable monomer composition A in S2 to the total monomer usage in the preparation method is 20-50%.

[0015] In one embodiment of the present invention, the combination ratio of the polymerizable monomer composition B in S3 is calculated according to the FOX formula, and the glass transition temperature Tg is 20-60°C.

[0016] In the present invention, the term Fox Tg refers to the glass transition temperature Tg calculated according to the Fox equation: 1 / Tg=W1 / Tg1+W2 / Tg2+···+Wn / Tgn. Wherein W1, W2, ...Wn refer to the mass fractions of monomers 1, 2, ...n in the combined monomers, respectively, and Tg1, Tg2, ...Tgn refer to the glass transition temperatures of the homopolymers of monomers 1, 2, ...n in the combined monomers, respectively. The design of the Fox Tg of the combined monomers is a well-known method in the art, and the technicians can combine and screen the existing disclosed monomers according to actual needs, and the present invention has no special requirements.

[0017] In one embodiment of the present invention, and / or, the polymerizable monomer composition B in S3 comprises one or more of a cross-linking monomer, an acrylate monomer, a methacrylate monomer, and a styrene monomer.

[0019] In one embodiment of the present invention, the cross-linking monomer in S3 is an allyl cross-linking monomer and / or an acrylate cross-linking monomer; preferably, the allyl cross-linking monomer comprises one or more of diallyl phthalate, diallyl carbonate, trimethylolpropane diallyl ether, pentaerythritol triallyl ether, and 2,2-bis(allyloxymethyl)-1-butanol; preferably, the acrylate cross-linking monomer comprises one or more of trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and polyethylene glycol di(meth)acrylate; preferably, the cross-linking monomer accounts for 0.1-1% by mass of the polymerized monomer composition B; preferably, the polymerized monomer composition B of the carrier shell in S3 is preferably added by dropwise addition.

[0020] In one embodiment of the present invention, the neutralizer used in S4 is a non-room temperature volatile alkaline neutralizer, preferably one or more of sodium hydroxide, potassium hydroxide, diethanolamine, dimethylethanolamine, and diethylethanolamine; preferably, the amount of the neutralizer added is 60-100% of the molar amount of the olefin acid monomer.

[0021] In one embodiment of the present invention, the cationic bactericide in S4 is preferably a quaternary ammonium salt bactericide and / or a quaternary phosphonium salt bactericide; preferably, the amount of the cationic bactericide added is 10-50% of the molar amount of the olefinic acid monomer; and / or, the neutralizer and the cationic bactericide in S4 are preferably added by dropwise addition.

[0022] In the present invention, the monomer addition method can be dropwise addition of mixed monomers or dropwise addition using an emulsifier to make a pre-emulsion; the monomer initiation method can be a heat-initiated emulsion polymerization reaction or a redox emulsion polymerization method using a redox initiator; the initiator is selected from a thermal initiator and / or a redox initiator; the thermal initiator is selected from one or more of ammonium persulfate, sodium persulfate, potassium persulfate, tert-butyl hydroperoxide, and hydrogen peroxide; the redox initiator contains an oxidant and a reductant; the oxidant is selected from one or more of ammonium persulfate, sodium persulfate, potassium persulfate, tert-butyl hydroperoxide, and hydrogen peroxide, preferably one or more of ammonium persulfate, sodium persulfate, and potassium persulfate; the reductant is selected from an alkali metal sulfite, preferably one or more of potassium and / or sodium salts, alkali metal hydrogen sulfide, acetone bisulfite, ascorbic acid, and isoascorbic acid. The above-mentioned initiation method and the initiator used therein, as well as the emulsifier, oxidant, reductant and other auxiliary agents used in the present invention are all well known in the art, and their selection and dosage do not affect the actual effect of the present invention.

[0023] Another object of the present invention is to provide an acrylic emulsion.

[0024] An acrylic emulsion is prepared by the above-mentioned preparation method, and the acrylic emulsion is an acrylic emulsion with pH value responsive antibacterial function.

[0025] In one embodiment of the present invention, when the environment of the emulsion surface becomes acidic due to the growth of microorganisms, the bactericide bound to the carboxyl group on the high molecular polymer is released as the pH value decreases, thereby forming a persistent antibacterial function.

[0026] In one embodiment of the present invention, the solid content of the emulsion is 10-60 wt%, preferably 30-50 wt%.

[0027] Another object of the present invention is to provide a use of acrylic emulsion.

[0028] A use of an acrylic emulsion, wherein the emulsion is the emulsion prepared by the above-mentioned preparation method, or is the above-mentioned emulsion, and the emulsion is used for coating in areas prone to moisture and mold.

[0029] Compared with the prior art, the positive effects of the present invention are:

[0030] When bacteria grow on the surface of the coating containing polymers, the acidic substances produced by the bacteria will cause the cationic bactericide to desorb from the carboxyl group, thereby releasing the bactericide to achieve an antibacterial effect. The coating prepared by the present invention can retain the bactericide in the coating for a longer time, and release the bactericide responsively to the adsorption and growth of bacteria. DETAILED DESCRIPTION

[0031] The present invention is further described below by means of specific examples. The examples described in the present invention are only used to illustrate the present invention and do not limit the scope of the present invention.

[0032] The sources of the raw materials used in the following examples are shown in the following table. Other raw materials are common commercially available unless otherwise specified:

[0033] Main raw materials and sources

[0034]

[0035]

[0036] The Fox Tg (degrees Celsius) of each combined monomer in the embodiment of the present invention is calculated according to the following formula:

[0037]

[0038] Where W1, W2, ...W nThey refer to the mass fractions of monomers 1, 2, ...n in the combined monomers, Tg1, Tg2, ...Tg n These respectively refer to the glass transition temperatures of homopolymers of monomers 1, 2, ... n in the monomer combination.

[0039] Example 1

[0040] A method for preparing an acrylic emulsion with pH-responsive antibacterial function, comprising the following steps:

[0041] Designed polymerizable monomer composition A: accounting for 40% of the total monomers used, of which olefinic acid monomers account for 30%;

[0042] Designing polymerizable monomer composition B: The theoretical glass transition temperature of the formed polymer is 39°C, and the cross-linking monomer in the polymerizable monomer composition B accounts for 0.5%;

[0043] 1) Add 130 g of deionized water and 0.2 g of emulsifier sodium dodecyl sulfate (SDS) into the reactor, start stirring, and raise the temperature in the reactor to 85°C;

[0044] 2) After the temperature of the material in the reactor is maintained at 85°C, 0.2g of initiator ammonium persulfate is dissolved in 2g of deionized water and added into the reactor as the initial initiator, and the temperature is kept for 5 minutes;

[0045] 3) 0.3 g of initiator APS was dissolved in 8 g of deionized water to obtain a dropwise initiator, 28 g of methyl methacrylate MMA and 12 g of acrylic acid AA were mixed evenly to obtain a polymerizable monomer composition A, and after the initial initiator was kept warm, the initiator and the polymerizable monomer composition A were synchronously added dropwise to the reactor through a peristaltic pump for 2 h, and the temperature was kept warm for 10 min after the addition was completed;

[0046] 4) 30 g of methyl methacrylate MMA, 17 g of butyl acrylate BA, 13 g of styrene ST, and 0.3 g of allyl methacrylate ALMA were uniformly mixed to obtain a polymerized monomer composition B. After the polymerized monomer composition A was kept warm, the initiator and the polymerized monomer composition B were synchronously added dropwise into the reactor through a peristaltic pump for 2 hours, and the temperature was kept warm for 30 minutes after the addition was completed;

[0047] 5) After the insulation is completed, 5.3 g of sodium hydroxide as a neutralizer and 17.6 g of dodecyltrimethylammonium chloride as a bactericide are diluted and mixed with 10 g of deionized water at 85°C, and then slowly added to the reactor by a peristaltic pump for 1 hour;

[0048] 6) After neutralization, the temperature is lowered to below 50° C. and the material is discharged to obtain an acrylic emulsion with a solid content of 40% and a pH-responsive antibacterial function.

[0049] Example 2

[0050] A method for preparing an acrylic emulsion with pH-responsive antibacterial function, comprising the following steps:

[0051] Designed polymerizable monomer composition A: accounting for 20% of the total monomers used, and olefinic acid monomers in the polymerizable monomer composition A accounting for 50%;

[0052] Designing polymerizable monomer composition B: The theoretical glass transition temperature of the formed polymer is 20°C, and the crosslinking monomer in the polymerizable monomer composition B accounts for 1%;

[0053] 1) Add 130 g of deionized water and 0.2 g of emulsifier sodium dodecyl sulfate (SDS) into the reactor, start stirring, and raise the temperature in the reactor to 85°C;

[0054] 2) After the temperature of the material in the reactor is maintained at 85°C, 0.2g of initiator ammonium persulfate is dissolved in 2g of deionized water and added into the reactor as the initial initiator, and the temperature is kept for 5 minutes;

[0055] 3) 0.3 g of initiator APS was dissolved in 8 g of deionized water to obtain a dropwise initiator, 10 g of methyl methacrylate MMA and 10 g of acrylic acid AA were mixed evenly to obtain a polymerizable monomer composition A, and after the initial initiator was kept warm, the initiator and the polymerizable monomer composition A were dropped into the reactor synchronously by a peristaltic pump for 1 h. After the addition was completed, the reactor was kept warm for 2 hours.

[0056] 10min;

[0057] 4) 30 g of methyl methacrylate MMA, 31 g of butyl acrylate BA, 19 g of styrene ST, and 0.8 g of allyl methacrylate ALMA were uniformly mixed to obtain a polymerized monomer composition B. After the polymerized monomer composition A was kept warm, the initiator and the polymerized monomer composition B were synchronously added dropwise into the reactor through a peristaltic pump for 3 hours. After the addition was completed, the temperature was kept warm for 30 minutes;

[0058] 5) After the insulation is completed, 5.5 g of sodium hydroxide as a neutralizer and 14.6 g of dodecyltrimethylammonium chloride as a bactericide are diluted and mixed with 10 g of deionized water at 85°C, and then slowly added to the reactor by a peristaltic pump for 1 hour;

[0059] 6) After neutralization, the temperature is lowered to below 50° C. and the material is discharged to obtain an acrylic emulsion with a solid content of 40% and a pH-responsive antibacterial function.

[0060] Example 3

[0061] A method for preparing an acrylic emulsion with pH-responsive antibacterial function, comprising the following steps:

[0062] Designed polymerizable monomer composition A: accounting for 50% of the total monomers used, and olefinic acid monomers in the polymerizable monomer composition A accounting for 10%;

[0063] Designing polymerizable monomer composition B: The theoretical glass transition temperature of the formed polymer is 60°C, and the proportion of crosslinking monomer in polymerizable monomer composition B is 0.1%;

[0064] 1) Add 130 g of deionized water and 0.2 g of emulsifier sodium dodecyl sulfate (SDS) into the reactor, start stirring, and raise the temperature in the reactor to 85°C;

[0065] 2) After the temperature of the material in the reactor is maintained at 85°C, 0.2g of initiator ammonium persulfate is dissolved in 2g of deionized water and added into the reactor as the initial initiator, and the temperature is kept for 5 minutes;

[0066] 3) 0.3 g of initiator APS was dissolved in 8 g of deionized water to obtain a dropwise initiator, 45 g of methyl methacrylate MMA and 5 g of acrylic acid AA were mixed evenly to obtain a polymerizable monomer composition A, and after the initial initiator insulation was completed, a peristaltic pump was used to pump the mixture.

[0067] Synchronously add initiator and polymerizable monomer composition A to the reactor for 2 hours. After the addition, keep warm for 10 minutes. 4) Add 30g methyl methacrylate MMA, 9g butyl acrylate BA, 11g styrene ST, 0.05g methacrylate

[0068] The polymerized monomer composition B obtained by mixing the propyl ester ALMA uniformly is synchronously added with the initiator and the polymerized monomer composition B into the reactor through a peristaltic pump after the polymerized monomer composition A is kept warm for 2 hours. After the addition is completed, the temperature is kept warm for 30 minutes.

[0069] 5) After the insulation is completed, 1.4 g of sodium hydroxide as a neutralizer and 3.6 g of dodecyltrimethylammonium chloride as a bactericide are diluted and mixed with 10 g of deionized water at 85°C, and then slowly added to the reactor by a peristaltic pump for 1 hour;

[0070] 6) After neutralization, the temperature is lowered to below 50° C. and the material is discharged to obtain an acrylic emulsion with a solid content of 40% and a pH-responsive antibacterial function.

[0071] Example 4

[0072] A method for preparing an acrylic emulsion with pH-responsive antibacterial function, comprising the following steps:

[0073] Designed polymerizable monomer composition A: accounting for 40% of the total monomers used, of which olefinic acid monomers account for 30%;

[0074] Designing polymerizable monomer composition B: The theoretical glass transition temperature of the formed polymer is 39°C, and the cross-linking monomer in the polymerizable monomer composition B accounts for 0.5%;

[0075] 1) Add 130 g of deionized water and 0.2 g of emulsifier sodium dodecyl sulfate (SDS) into the reactor, start stirring, and raise the temperature in the reactor to 70°C;

[0076] 2) After the temperature of the material in the reactor is maintained at 70° C., 0.1 g of tert-butyl hydroperoxide TBHP dissolved in 1 g of deionized water and 0.05 g of ascorbic acid IAA dissolved in 1 g of deionized water are added into the reactor as initial initiators and kept warm for 5 minutes;

[0077] 3) dissolving 0.4 g of tert-butyl hydroperoxide TBHP in 4 g of deionized water and dissolving 0.25 g of ascorbic acid IAA in 4 g of deionized water to obtain a dropwise initiator, and uniformly mixing 28 g of methyl methacrylate MMA and 12 g of methacrylic acid MAA to obtain a polymerizable monomer composition A. After the initial initiator is kept warm, the initiator and the polymerizable monomer composition A are synchronously added dropwise to the reactor through a peristaltic pump for 2 hours. After the addition is completed, the mixture is kept warm for 10 minutes.

[0078] 4) 30 g of methyl methacrylate MMA, 17 g of butyl acrylate BA, 13 g of styrene ST, and 0.3 g of allyl methacrylate ALMA were uniformly mixed to obtain a polymerized monomer composition B. After the polymerized monomer composition A was kept warm, the initiator and the polymerized monomer composition B were synchronously added dropwise into the reactor through a peristaltic pump for 2 hours, and the temperature was kept warm for 30 minutes after the addition was completed;

[0079] 5) After the insulation is completed, 4.5 g of sodium hydroxide as a neutralizer and 14.7 g of dodecyltrimethylammonium chloride as a bactericide are diluted and mixed with 10 g of deionized water at 70°C, and then slowly added to the reactor by a peristaltic pump for 1 hour;

[0080] 6) After neutralization, the temperature is lowered to below 50° C. and the material is discharged to obtain an acrylic emulsion with a solid content of 40% and a pH-responsive antibacterial function.

[0081] Example 5

[0082] A method for preparing an acrylic emulsion with pH-responsive antibacterial function, comprising the following steps:

[0083] Designed polymerizable monomer composition A: accounting for 40% of the total monomers used, of which olefinic acid monomers account for 30%;

[0084] Designing polymerizable monomer composition B: The theoretical glass transition temperature of the formed polymer is 39°C, and the crosslinking monomer in the polymerizable monomer composition B accounts for 0.5%;

[0085] 1) Add 130 g of deionized water and 0.2 g of emulsifier sodium dodecyl sulfate (SDS) into the reactor, start stirring, and raise the temperature in the reactor to 85°C;

[0086] 2) After the temperature of the material in the reactor is maintained at 85°C, 0.2g of initiator ammonium persulfate is dissolved in 2g of deionized water and added into the reactor as the initial initiator, and the temperature is kept for 5 minutes;

[0087] 3) 0.3 g of initiator APS was dissolved in 8 g of deionized water to obtain a dropwise initiator, 28 g of methyl methacrylate MMA and 12 g of acrylic acid AA were mixed evenly to obtain a polymerizable monomer composition A, and after the initial initiator was kept warm, the initiator and the polymerizable monomer composition A were synchronously added dropwise to the reactor through a peristaltic pump for 2 h, and the temperature was kept warm for 10 min after the addition was completed;

[0088] 4) 30 g of methyl methacrylate MMA, 17 g of butyl acrylate BA, 13 g of styrene ST, and 0.3 g of allyl methacrylate ALMA were uniformly mixed to obtain a polymerized monomer composition B. After the polymerized monomer composition A was kept warm, the initiator and the polymerized monomer composition B were synchronously added dropwise into the reactor through a peristaltic pump for 2 hours, and the temperature was kept warm for 30 minutes after the addition was completed;

[0089] 5) After the insulation is completed, 4g of sodium hydroxide as a neutralizer and 25g of tributyl tetradecyl phosphonium chloride as a bactericide are diluted and mixed with 10g of deionized water at 85°C, and then slowly added to the reactor by a peristaltic pump for 1 hour;

[0090] 6) After neutralization, the temperature is lowered to below 50° C. and the material is discharged to obtain an acrylic emulsion with a solid content of 40% and a pH-responsive antibacterial function.

[0091] Example 6

[0092] A method for preparing an acrylic emulsion with pH-responsive antibacterial function, comprising the following steps:

[0093] Designed polymerizable monomer composition A: accounting for 40% of the total monomers used, of which olefinic acid monomers account for 30%;

[0094] Designing polymerizable monomer composition B: The theoretical glass transition temperature of the formed polymer is 39°C, and the cross-linking monomer in the polymerizable monomer composition B accounts for 0.5%;

[0095] 1) Add 130 g of deionized water and 0.2 g of emulsifier sodium dodecyl sulfate (SDS) into the reactor, start stirring, and raise the temperature in the reactor to 85°C;

[0096] 2) After the temperature of the material in the reactor is maintained at 85°C, 0.2g of initiator ammonium persulfate is dissolved in 2g of deionized water and added into the reactor as the initial initiator, and the temperature is kept for 5 minutes;

[0097] 3) 0.3 g of initiator APS was dissolved in 8 g of deionized water to obtain a dropwise initiator, 28 g of methyl methacrylate MMA and 12 g of acrylic acid AA were mixed evenly to obtain a polymerizable monomer composition A, and after the initial initiator was kept warm, the initiator and the polymerizable monomer composition A were synchronously added dropwise to the reactor through a peristaltic pump for 2 h, and the temperature was kept warm for 10 min after the addition was completed;

[0098] 4) 30 g of methyl methacrylate MMA, 17 g of butyl acrylate BA, 13 g of styrene ST, and 0.3 g of allyl methacrylate ALMA were uniformly mixed to obtain a polymerized monomer composition B. After the polymerized monomer composition A was kept warm, the initiator and the polymerized monomer composition B were synchronously added dropwise into the reactor through a peristaltic pump for 2 hours, and the temperature was kept warm for 30 minutes after the addition was completed;

[0099] 5) After the heat preservation is completed, 10g of dimethylethanolamine as a neutralizer and 4.4g of dodecyltrimethylammonium chloride as a bactericide are diluted and mixed with 10g of deionized water at 85°C, and then slowly added to the reactor by a peristaltic pump for 1 hour;

[0100] 6) After neutralization, the temperature is lowered to below 50° C. and the material is discharged to obtain an acrylic emulsion with a solid content of 40% and a pH-responsive antibacterial function.

[0101] Example 7

[0102] A method for preparing an acrylic emulsion with pH-responsive antibacterial function, comprising the following steps:

[0103] Designed polymerizable monomer composition A: accounting for 40% of the total monomers used, of which olefinic acid monomers account for 30%;

[0104] Designing polymerizable monomer composition B: The theoretical glass transition temperature of the formed polymer is 40°C, and the crosslinking monomer in the polymerizable monomer composition B accounts for 0.5%;

[0105] 1) Add 130 g of deionized water and 0.2 g of emulsifier sodium dodecyl sulfate (SDS) into the reactor, start stirring, and raise the temperature in the reactor to 85°C;

[0106] 2) After the temperature of the material in the reactor is maintained at 85°C, 0.2g of initiator ammonium persulfate is dissolved in 2g of deionized water and added into the reactor as the initial initiator, and the temperature is kept for 5 minutes;

[0107] 3) 0.3 g of initiator APS was dissolved in 8 g of deionized water to obtain a dropwise initiator, 28 g of methyl methacrylate MMA, 12 g of acrylic acid AA, 0.1 g of emulsifier sodium dodecyl sulfate SDS and 10 g of deionized water were mixed and dispersed to obtain a pre-emulsion of the polymerization monomer composition A, and after the initial initiator was kept warm, the initiator and the pre-emulsion of the polymerization monomer composition A were synchronously added dropwise to the reactor through a peristaltic pump for 2 hours, and the mixture was kept warm for 10 minutes after the addition was completed;

[0108] 4) 43g methyl methacrylate MMA, 17g butyl acrylate BA, 0.3g diallyl phthalate DAP,

[0109] 0.1g of emulsifier sodium dodecyl sulfate SDS and 10g of deionized water are mixed and dispersed to obtain a pre-emulsion of the polymerization monomer composition B. After the polymerization monomer composition A is kept warm, the initiator and the pre-emulsion of the polymerization monomer composition B are synchronously added to the reactor by a peristaltic pump. The addition time is 2h, and the temperature is kept warm for 30min after the addition is completed.

[0110] 5) After the insulation is completed, 4g of sodium hydroxide as a neutralizer and 11.6g of dodecyltrimethylammonium chloride as a bactericide are diluted and mixed with 10g of deionized water at 85°C, and then slowly added to the reactor by a peristaltic pump for 1 hour;

[0111] 6) After neutralization, the temperature is lowered to below 50° C. and the material is discharged to obtain an acrylic emulsion with a solid content of 35% and a pH-responsive antibacterial function.

[0112] Example 8

[0113] A method for preparing an acrylic emulsion with pH-responsive antibacterial function, comprising the following steps:

[0114] Designed polymerizable monomer composition A: accounting for 40% of the total monomers used, of which olefinic acid monomers account for 30%;

[0115] Designing polymerizable monomer composition B: The theoretical glass transition temperature of the formed polymer is 39°C, and the crosslinking monomer in the polymerizable monomer composition B accounts for 0.5%;

[0116] 1) Add 130 g of deionized water and 0.2 g of emulsifier sodium dodecyl sulfate (SDS) into the reactor, start stirring, and raise the temperature in the reactor to 85°C;

[0117] 2) After the temperature of the material in the reactor is maintained at 85°C, 0.2g of initiator ammonium persulfate is dissolved in 2g of deionized water and added into the reactor as the initial initiator, and the temperature is kept for 5 minutes;

[0118] 3) 0.3 g of initiator APS was dissolved in 8 g of deionized water to obtain a dropwise initiator, 28 g of methyl methacrylate MMA and 12 g of acrylic acid AA were mixed evenly to obtain a polymerizable monomer composition A, and after the initial initiator was kept warm, the initiator and the polymerizable monomer composition A were synchronously added dropwise to the reactor through a peristaltic pump for 2 h, and the temperature was kept warm for 10 min after the addition was completed;

[0119] 4) 30 g of methyl methacrylate MMA, 17 g of butyl acrylate BA, 13 g of styrene ST, 0.1 g of allyl methacrylate ALMA, and 0.2 g of diallyl phthalate DAP were uniformly mixed to obtain a polymerized monomer composition B. After the polymerized monomer composition A was kept warm, the initiator and the polymerized monomer composition B were synchronously added dropwise into the reactor through a peristaltic pump for 2 hours, and the temperature was kept warm for 30 minutes after the addition was completed;

[0120] 5) After the insulation is completed, 5.3 g of sodium hydroxide as a neutralizer and 17.6 g of dodecyltrimethylammonium chloride as a bactericide are diluted and mixed with 10 g of deionized water at 85°C, and then slowly added to the reactor by a peristaltic pump for 1 hour;

[0121] 6) After neutralization, the temperature is lowered to below 50° C. and the material is discharged to obtain an acrylic emulsion with a solid content of 40% and a pH-responsive antibacterial function.

[0122] Example 9

[0123] A method for preparing an acrylic emulsion with pH-responsive antibacterial function, comprising the following steps:

[0124] Designed polymerizable monomer composition A: accounting for 40% of the total monomers used, of which olefinic acid monomers account for 30%;

[0125] Designing polymerizable monomer composition B: The theoretical glass transition temperature of the formed polymer is 39°C, and the cross-linking monomer in the polymerizable monomer composition B accounts for 0.5%;

[0126] 1) Add 130 g of deionized water and 0.2 g of emulsifier sodium dodecyl sulfate (SDS) into the reactor, start stirring, and raise the temperature in the reactor to 90°C;

[0127] 2) After the temperature of the material in the reactor is maintained at 90°C, 0.2g of initiator ammonium persulfate is dissolved in 2g of deionized water and added into the reactor as the initial initiator, and the temperature is kept for 5 minutes;

[0128] 3) 0.3 g of initiator APS was dissolved in 8 g of deionized water to obtain a dropwise initiator, 10 g of methyl methacrylate MMA, 4 g of butyl acrylate BA, 14 g of styrene ST, and 12 g of acrylic acid AA were uniformly mixed to obtain a polymerizable monomer composition A, and after the initial initiator was kept warm, the initiator and the polymerizable monomer composition A were synchronously added dropwise to the reactor through a peristaltic pump for 2 hours, and the mixture was kept warm for 10 minutes after the addition was completed;

[0129] 4) 30 g of methyl methacrylate MMA, 17 g of butyl acrylate BA, 13 g of styrene ST, and 0.3 g of allyl methacrylate ALMA were uniformly mixed to obtain a polymerized monomer composition B. After the polymerized monomer composition A was kept warm, the initiator and the polymerized monomer composition B were synchronously added dropwise into the reactor through a peristaltic pump for 2 hours, and the temperature was kept warm for 30 minutes after the addition was completed;

[0130] 5) After the insulation is completed, 5.3 g of sodium hydroxide as a neutralizer and 17.6 g of dodecyltrimethylammonium chloride as a bactericide are diluted and mixed with 10 g of deionized water at 90°C, and then slowly added to the reactor by a peristaltic pump for 1 hour;

[0131] 6) After neutralization, the temperature is lowered to below 50° C. and the material is discharged to obtain an acrylic emulsion with a solid content of 40% and a pH-responsive antibacterial function.

[0132] Comparative Example 1

[0133] Compared with Example 1: the proportion of olefinic acid monomers in the polymerizable monomer composition A is designed to be 60%, and the others are the same.

[0134] 1) Add 130 g of deionized water and 0.2 g of emulsifier sodium dodecyl sulfate (SDS) into the reactor, start stirring, and raise the temperature in the reactor to 85°C;

[0135] 2) After the temperature of the material in the reactor is maintained at 85°C, 0.2g of initiator ammonium persulfate is dissolved in 2g of deionized water and added into the reactor as the initial initiator, and the temperature is kept for 5 minutes;

[0136] 3) 0.3 g of initiator APS was dissolved in 8 g of deionized water to obtain a dropwise initiator, 16 g of methyl methacrylate MMA and 24 g of acrylic acid AA were mixed evenly to obtain a polymerizable monomer composition A, and after the initial initiator was kept warm, the initiator and the polymerizable monomer composition A were synchronously added dropwise to the reactor through a peristaltic pump for 2 h, and the temperature was kept warm for 10 min after the addition was completed;

[0137] 4) 30 g of methyl methacrylate MMA, 17 g of butyl acrylate BA, 13 g of styrene ST, and 0.3 g of allyl methacrylate ALMA were uniformly mixed to obtain a polymerized monomer composition B. After the polymerized monomer composition A was kept warm, the initiator and the polymerized monomer composition B were synchronously added dropwise into the reactor through a peristaltic pump for 2 hours, and the temperature was kept warm for 30 minutes after the addition was completed;

[0138] 5) After the insulation is completed, 10.6 g of sodium hydroxide as a neutralizer and 35.2 g of dodecyltrimethylammonium chloride as a bactericide are diluted and mixed with 10 g of deionized water at 85°C, and then slowly added to the reactor by a peristaltic pump for 1 hour;

[0139] 6) After neutralization, the temperature is lowered to below 50° C. and the material is discharged to obtain an acrylic emulsion with a solid content of 40% and a pH-responsive antibacterial function.

[0140] Comparative Example 2

[0141] Compared with Example 1: the bactericide used is the non-cationic bactericide p-chloro-meta-xylenol; the others are the same.

[0142] 1) Add 130 g of deionized water and 0.2 g of emulsifier sodium dodecyl sulfate (SDS) into the reactor, start stirring, and raise the temperature in the reactor to 85°C;

[0143] 2) After the temperature of the material in the reactor is maintained at 85°C, 0.2g of initiator ammonium persulfate is dissolved in 2g of deionized water and added into the reactor as the initial initiator, and the temperature is kept for 5 minutes;

[0144] 3) 0.3 g of initiator APS was dissolved in 8 g of deionized water to obtain a dropwise initiator, 28 g of methyl methacrylate MMA and 12 g of acrylic acid AA were mixed evenly to obtain a polymerizable monomer composition A, and after the initial initiator was kept warm, the initiator and the polymerizable monomer composition A were synchronously added dropwise to the reactor through a peristaltic pump for 2 h, and the temperature was kept warm for 10 min after the addition was completed;

[0145] 4) 30 g of methyl methacrylate MMA, 17 g of butyl acrylate BA, 13 g of styrene ST, and 0.3 g of allyl methacrylate ALMA were uniformly mixed to obtain a polymerized monomer composition B. After the polymerized monomer composition A was kept warm, the initiator and the polymerized monomer composition B were synchronously added dropwise into the reactor through a peristaltic pump for 2 hours, and the temperature was kept warm for 30 minutes after the addition was completed;

[0146] 5) After the insulation is completed, 5.3 g of sodium hydroxide as a neutralizer and 10.4 g of para-chloro-metaxylenol as a bactericide are diluted and mixed with 10 g of deionized water at 85°C, and then slowly added to the reactor by a peristaltic pump for 1 hour;

[0147] 6) After neutralization, the temperature is lowered to below 50° C. and the material is discharged to obtain an acrylic emulsion with a solid content of 40% and a pH-responsive antibacterial function.

[0148] Comparative Example 3

[0149] Compared with Example 1: the proportion of olefinic acid monomers in the polymerization monomer composition A is 5%; the others are the same.

[0150] 1) Add 130 g of deionized water and 0.2 g of emulsifier sodium dodecyl sulfate (SDS) into the reactor, start stirring, and raise the temperature in the reactor to 85°C;

[0151] 2) After the temperature of the material in the reactor is maintained at 85°C, 0.2g of initiator ammonium persulfate is dissolved in 2g of deionized water and added into the reactor as the initial initiator, and the temperature is kept for 5 minutes;

[0152] 3) 0.3 g of initiator APS was dissolved in 8 g of deionized water to obtain a dropwise initiator, 38 g of methyl methacrylate MMA and 2 g of acrylic acid AA were evenly mixed to obtain a polymerizable monomer composition A, and after the initial initiator was kept warm, the initiator and the polymerizable monomer composition A were synchronously added dropwise to the reactor through a peristaltic pump for 2 h, and the temperature was kept warm for 10 min after the addition was completed;

[0153] 4) 30 g of methyl methacrylate MMA, 17 g of butyl acrylate BA, 13 g of styrene ST, and 0.3 g of allyl methacrylate ALMA were uniformly mixed to obtain a polymerized monomer composition B. After the polymerized monomer composition A was kept warm, the initiator and the polymerized monomer composition B were synchronously added dropwise into the reactor through a peristaltic pump for 2 hours, and the temperature was kept warm for 30 minutes after the addition was completed;

[0154] 5) After the insulation is completed, 0.9g of sodium hydroxide as a neutralizer and 2.9g of dodecyl trimethyl ammonium chloride as a bactericide are mixed at 85°C.

[0155] 10g of deionized water was diluted and mixed, and then slowly added to the reactor by a peristaltic pump for 1 hour.

[0156] 6) After neutralization, the temperature is lowered to below 50° C. and the material is discharged to obtain an acrylic emulsion with a solid content of 40% and a pH-responsive antibacterial function.

[0157] The performance testing method adopted by the present invention is as follows:

[0158] Sterilization efficiency: Take out an appropriate amount of culture solution containing bacteria from the bacterial culture solution and add it to the sample to be tested. After the test sample and bacteria are evenly mixed, the control group is a sample mixed with an equal amount of bacterial culture solution and deionized water. The test sample containing bacteria is cultured on a bacterial agar plate, and the sterilization efficiency is determined by the number of bacterial colonies on the culture plate. Sterilization efficiency = 1-the number of bacteria on the test sample agar plate / the number of bacteria on the control group agar plate.

[0159] Verify the pH response performance: The prepared acrylic emulsion with pH-responsive antibacterial function is centrifuged, and the lower layer is the cationic bactericide carrier. The upper clear liquid is taken out and the lower carrier is redispersed with deionized water. The redispersed emulsion is added with a pH regulator to adjust the system pH to <6, and then mixed with the bacterial culture solution to test the bactericidal efficiency.

[0160] The test results of the acrylic emulsions with pH-responsive antibacterial function prepared in Examples 1-8 and Comparative Examples 1-5 are shown in the following table:

[0161]

[0162] Finally, it should be noted that the above embodiments are only used to describe the preferred implementation methods of the present invention, rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that various modifications and improvements made by modifying or equivalently replacing the technical solution of the present invention should fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing an acrylic emulsion, characterized in that: The preparation method comprises the following steps: S1: Add emulsifier and water into the reactor, stir and heat up; S2: adding a polymerizable monomer composition A having an olefinic acid monomer and adding an initiator to react; S3: After the reaction is completed, the polymerizable monomer composition B of the carrier shell is added, and an initiator is added to react to form a polymer; S4: adding a neutralizing agent and a cationic bactericide to the polymer to obtain a target acrylic emulsion.

2. The preparation method according to claim 1, characterized in that: The heating temperature in S1 is 60-95°C.

3. The preparation method according to claim 1 or 2, characterized in that: The polymerizable monomer composition A in S2 is composed of one or more of olefinic acid monomers, (meth)acrylate monomers, and styrene monomers; Preferably, the olefinic acid monomer comprises one or more of acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, preferably acrylic acid and / or methacrylic acid; Preferably, the mass ratio of the olefinic acid monomer to the polymerizable monomer composition A is 10-50%; Preferably, the mass ratio of the polymerizable monomer composition A in S2 to the total monomer usage in the preparation method is 20-50%.

4. The preparation method according to any one of claims 1 to 3, characterized in that The combination ratio of the polymerizable monomer composition B in S3 is calculated according to the FOX formula, and the glass transition temperature Tg is 20-60° C.; and / or, the polymerizable monomer composition B in S3 comprises one or more of a cross-linking monomer, a (meth)acrylate monomer, and a styrene monomer; And / or, the cross-linking monomer in S3 is an allyl cross-linking monomer and / or an acrylate cross-linking monomer; Preferably, the allyl crosslinking monomer comprises one or more of diallyl phthalate, diallyl carbonate, trimethylolpropane diallyl ether, pentaerythritol triallyl ether, and 2,2-bis(allyloxymethyl)-1-butanol; Preferably, the acrylate crosslinking monomer comprises one or more of trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and polyethylene glycol di(meth)acrylate; Preferably, the cross-linking monomer accounts for 0.1-1% by mass of the polymerizable monomer composition B; Preferably, the polymerizable monomer composition B of the carrier shell in S3 is added dropwise.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The neutralizer used in S4 is a non-room temperature volatile alkaline neutralizer, preferably one or more of sodium hydroxide, potassium hydroxide, diethanolamine, dimethylethanolamine, and diethylethanolamine; Preferably, the amount of the neutralizing agent added is 60-100% of the molar amount of the olefinic acid monomer; And / or, the cationic fungicide in S4 is preferably a quaternary ammonium salt fungicide and / or a quaternary phosphonium salt fungicide; Preferably, the cationic bactericide is added in an amount of 10-50% of the molar amount of the olefinic acid monomer; And / or, the neutralizer and the cationic bactericide in S4 are preferably added dropwise.

6. An acrylic emulsion, which is prepared by the preparation method according to any one of claims 1 to 5, characterized in that: The acrylic emulsion is an acrylic emulsion with pH-responsive antibacterial function.

7. The emulsion according to claim 6, characterized in that When the environment of the emulsion becomes acidic due to the growth of microorganisms on the surface of the emulsion, the bactericide bound to the carboxyl group on the high molecular polymer is released as the pH value decreases, thereby forming a lasting antibacterial function; And / or, the solid content of the emulsion is 10-60wt%, preferably 30-50wt%.

8. Use of an acrylic emulsion, wherein the emulsion is the emulsion prepared by the preparation method according to any one of claims 1 to 5, or the emulsion according to claim 6 or 7, and the emulsion is used as a coating for areas prone to moisture and mold.

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