An antibacterial soap-free polymer dispersion and its preparation method and application

Abstract

The present invention relates to a polymer dispersion, in particular to an antibacterial soap-free polymer dispersion and its preparation method and application, comprising the following steps: S1: mixing a first monomer composition a1, a surfactant a2 and an initiator a3; S2: subjecting the emulsion A obtained in step S1 to emulsion polymerization; S3: adding a second monomer composition b1 to the first polymer particle dispersion P1 obtained in step S2; S4: subjecting the mixture B obtained in step S3 to emulsion polymerization; S5: adding a crosslinking agent to the second polymer particle dispersion P2 obtained in step S4 to obtain an antibacterial soap-free polymer dispersion. Compared with the prior art, the polymer dispersion of the present invention does not have free emulsifiers, and various properties are improved; the solid content is high, the film-forming time is short, and the production efficiency is high; there is no amine and no odor; the coating prepared further has a strong killing ability against a variety of microorganisms, and still has a strong bactericidal effect after using an anionic detergent.

Description

Technical Field

[0001] The invention relates to a polymer dispersion, in particular to an antibacterial soap-free polymer dispersion and a preparation method and application thereof. Background Art

[0002] How to reduce the threat of emerging diseases and microorganisms to humans has become a century-long issue. Therefore, developing a coating that can inhibit bacteria and viruses on the surface of materials for a long time has become an urgent research and development task for coating engineers.

[0003] Antibacterial coatings will encounter wear and loss of antibacterial agents during long-term use. For example, silver, copper and other nanoparticles will continuously release silver ions or copper ions in the coating, causing the antibacterial effectiveness of the coating surface to decrease over time. In order to obtain excellent and lasting surface contact antibacterial properties, monomers with antibacterial functional groups can be polymerized into the coating resin, so that the antibacterial substances have no migration and loss, achieving the purpose of long-term protection.

[0004] The use of emulsion polymerization process to synthesize antibacterial coating resins has the advantages of energy saving and environmental protection. Surfactants are an indispensable component in emulsion polymerization. Traditional surfactants are adsorbed to the surface of latex particles through physical action, and the adsorption force is very weak, so that the surfactants will be desorbed from the surface of latex particles, resulting in instability of the latex, poor adhesion of the paint film, sensitivity to water and poor gloss.

[0005] CN 111184025 B discloses a method for preparing a silver-ruthenium bimetallic antibacterial material. The silver-ruthenium bimetallic material forms a micro-battery structure. When used, active oxygen substances can be continuously obtained through a two-electron oxygen reduction reaction and a Fenton-like reaction without light exposure, thereby achieving the purpose of broad-spectrum antibacterial. The disadvantage of the method is that when the antibacterial material is added to a coating for use, the antibacterial material cannot be stably dispersed in the coating and is very easy to agglomerate, resulting in a poor paint film.

[0006] CN 112552803 B discloses an antibacterial coil coating with water resistance, and describes a citronellol-modified silk extract fibroin and acrylic emulsion composite to obtain a water-resistant antibacterial emulsion for use in antibacterial coatings. However, the modified fibroin and acrylic emulsion are simply physically mixed, and the long-term stability of the emulsion storage cannot be guaranteed. The modified fibroin with a linear structure has no chemical connection with the polymer particles in the acrylic emulsion, which is not conducive to the chemical resistance and wear resistance of the paint film. The antibacterial performance of the paint film has not been experimentally evaluated, and there are no specific antibacterial parameters.

[0007] CN 107325210 B describes a cross-linked polymer antibacterial nano latex particle and a preparation method thereof. No emulsifier is used in the emulsion polymerization stage, and the latex particles in the system are stabilized by the cationic groups provided by the quaternary ammonium salt monomer. The emulsion containing the quaternary ammonium salt is shaken with the bacterial solution in a 1:1 ratio, and the result shows good antibacterial properties against Escherichia coli. However, the monomers used in the emulsion polymerization of this patent contain a considerable amount of styrene, and the flexibility and weather resistance of the paint film are relatively poor, and the minimum film forming temperature (MFT) is high, which is not conducive to construction under low temperature conditions. The patent also fails to evaluate the antibacterial properties of the paint film under actual use conditions. Summary of the invention

[0008] The purpose of the present invention is to solve at least one of the above problems and to provide an antibacterial soap-free polymer dispersion and its preparation method and application, so as to realize a polymer dispersion that can be used to prepare antibacterial coatings. The prepared antibacterial coatings have strong killing ability against microorganisms such as methicillin-resistant Staphylococcus aureus, fungi, Mycobacterium tuberculosis, hydrophilic viruses and bacterial spores, and still have a bactericidal effect after the surface is cleaned with an anion-containing detergent.

[0009] The purpose of the present invention is achieved through the following technical solutions:

[0010] The first aspect of the present invention discloses a method for preparing an antibacterial soap-free polymer dispersion, comprising the following steps:

[0011] S1: mixing a first monomer composition a1, a surfactant a2 and an initiator a3 to obtain an emulsion A;

[0012] S2: subjecting the emulsion A obtained in step S1 to emulsion polymerization to obtain a first polymer particle dispersion P1;

[0013] S3: adding the second monomer composition b1 to the first polymer particle dispersion P1 obtained in step S2 to obtain a mixture B;

[0014] S4: subjecting the mixture B obtained in step S3 to emulsion polymerization to obtain a second polymer particle dispersion P2;

[0015] S5: adding a crosslinking agent to the second polymer particle dispersion P2 obtained in step S4 to obtain the antibacterial soap-free polymer dispersion;

[0016] in,

[0017] The first monomer composition a1 includes a nitrogen-containing heterocyclic olefin monomer, a crosslinking monomer, other olefin monomers and a chain transfer agent;

[0018] The second monomer composition b1 includes a nitrogen-containing heterocyclic olefin monomer and other olefin monomers.

[0019] In the first stage of polymerization, the first monomer composition a1, the surfactant a2 and the initiator a3 are mixed in water to prepare an emulsion A. The components in the emulsion A can be added in any of several different orders known in the art, for example: the monomers in the first monomer composition a1 can be premixed and added or added separately, can be added continuously or in one or more parts, can be added before, during or after the addition of water, surfactants, initiators, and can be added before, during or after heating to the reaction temperature.

[0020] In the second stage of polymerization, the second monomer composition b1 may be added dropwise to the reaction vessel continuously, or may be added stepwise.

[0021] Preferably, the first monomer composition a1 comprises:

[0022] 1 to 20 parts by weight of a nitrogen-containing heterocyclic olefin monomer, preferably 2 to 15 parts by weight of a nitrogen-containing heterocyclic olefin monomer, and more preferably 3 to 10 parts by weight of a nitrogen-containing heterocyclic olefin monomer;

[0023] 1 to 20 parts by weight of a cross-linking monomer, preferably 3 to 15 parts by weight of a cross-linking monomer, and more preferably 5 to 10 parts by weight of a cross-linking monomer;

[0024] 50 to 99 parts by weight of other olefinic monomers, preferably 60 to 95 parts by weight of other olefinic monomers, and more preferably 65 to 90 parts by weight of other olefinic monomers;

[0025] and 0.05 to 1 parts by mass of a chain transfer agent.

[0026] Preferably, the second monomer composition b1 comprises 1 to 10 parts by mass of a nitrogen-containing heterocyclic olefin monomer and 10 to 50 parts by mass of other olefin monomers.

[0027] Preferably, the amount of the surfactant a2 is 0.05 to 5 wt% of the first monomer composition a1; more preferably 0.1 to 3 wt%; and even more preferably 0.5 to 2 wt%.

[0028] Preferably, the amount of the initiator a3 is 0.05-5 wt% of the first monomer composition a1; more preferably 0.2-3 wt%.

[0029] Preferably, the amount of the second monomer composition b1 is 15 to 85 wt % of the total amount of the first monomer composition a1 and the second monomer composition b1; more preferably 25 to 75 wt %; and even more preferably 35 to 65 wt %.

[0030] Preferably, the average particle size of the first polymer particle dispersion P1 is less than 90 nm; more preferably less than 60 nm; and even more preferably less than 50 nm;

[0031] The Tg of the first polymer particle dispersion P1 is 5 to 130°C, more preferably 25 to 130°C, and even more preferably 45 to 130°C.

[0032] Preferably, the second polymer particle dispersion P2 is a core-shell structure polymer particle dispersion;

[0033] Its solid content is 40-70%, more preferably 45-65%;

[0034] The average particle size of the second polymer particle dispersion P2 is less than 150 nm; more preferably less than 125 nm; and even more preferably less than 100 nm;

[0035] The content of polymer particles with a particle size greater than 100 nm is less than 25wt%; preferably less than 15wt%; further preferably less than 10wt%; polymer particles with a particle size greater than 100 nm will affect the gloss of the coating of the final product. When the content is less than 25wt%, a coating with better gloss can be formed. When the content is further reduced, the gloss of the coating is better.

[0036] The Tg of the second polymer particle dispersion P2 is at least 20°C lower than the Tg of the first polymer particle dispersion P1; preferably at least 35°C;

[0037] Typically, the Tg of the second polymer particle dispersion P2 is -60 to 60°C; preferably -30 to 40°C.

[0038] The polymer particle dispersion after polymerization is a core-shell structure. The first polymer particle dispersion P1 forms a core. The Tg of this stage is relatively high in order to increase the Tg of the polymer. The second polymer particle dispersion P2 forms a shell. The Tg of this stage is relatively low in order to reduce the film-forming temperature. The average particle size of the first polymer particle dispersion P1 and the second polymer particle dispersion P2 is the Z-average average value measured by dynamic light scattering. The second polymer particle dispersion P2 with a core-shell structure obtained by the second stage polymerization has a small particle size and a concentrated particle size distribution, and has excellent stability, and can produce a stable emulsion with a high solid content.

[0039] Preferably, the nitrogen-containing heterocyclic olefin monomer is one or more of N-thiolated β-lactam derivatives, quinoline derivatives and sulfamethoxazole derivatives. The nitrogen-containing heterocyclic olefin monomer has antibacterial function and can participate in polymerization, so in the prepared coating resin, it does not have migration and loss, and can achieve the purpose of long-term protection; the nitrogen-containing heterocyclic olefin monomer is a non-salt antibacterial monomer, which acts similarly to antimicrobial peptides, acts on the cell membrane, can form transmembrane ion channels on the membrane, destroy the integrity of the membrane, and then can cause leakage of cell contents, thereby killing cells.

[0040] Further preferably, the nitrogen-containing heterocyclic olefin monomer is selected from one or more compounds of the following formulas I to VIII:

[0041]

[0042] Among them, formula I to formula IV are N-thiol β-lactam derivatives; formula V is a quinoline derivative; and formula VI to formula VIII are sulfamethoxazole derivatives.

[0043] Preferably, the crosslinking monomer is one or more of allyl methacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, trimethylolpropane triacrylate, divinylbenzene, dicyclopentenyl acrylate, glycidyl methacrylate, acetoacetoxyethyl methacrylate, acrolein, methacrolein, diacetone acrylamide, ethyl methacrylate isocyanato and 3-isopropenyl-α,α-dimethylbenzyl isocyanate. The crosslinking monomer is introduced into the polymer in order to introduce crosslinking points, which can react with the crosslinking agent to form an interpenetrating network structure, thereby effectively improving the chemical resistance and hardness of the coating.

[0044] Preferably, the other olefinic monomers include one or more of olefinic unsaturated vinyl monomers, vinyl halides, vinylidene halides, vinyl esters, alkyl esters of monoethylenically unsaturated dicarboxylic acids, esters of methacrylic acid and nonionic monomers. Other olefinic monomers are the main synthetic raw materials for polymers. Different types and amounts of other olefinic monomers can be selected for synthesis according to the performance requirements to be met by the product coating film, thereby meeting the performance requirements.

[0045] Preferably, the ethylenically unsaturated vinyl monomer is one or more of 1,3-butadiene, isoprene, divinylbenzene, styrene and α-methylstyrene.

[0046] Preferably, the vinyl halide is vinyl chloride.

[0047] Preferably, the vinylidene halide is vinylidene chloride.

[0048] Preferably, the vinyl ester is one or more of vinyl acetate, vinyl propionate, butyl acrylate and vinyl laurate.

[0049] Preferably, the alkyl ester of the monoethylenically unsaturated dicarboxylic acid is di-n-butyl maleate and / or di-n-butyl fumarate.

[0050] Preferably, the methacrylic acid ester is of the formula CH2=CR 5 -COOR 4 Methacrylic acid esters, wherein R 5 is H or methyl, R 4 It is an optionally substituted C1 to C20, more preferably C1 to C8 alkyl, cycloalkyl, aryl or (alkyl)aryl group.

[0051] Preferably, the ester of methacrylic acid is selected from one or more of methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate, isopropyl methacrylate, propyl methacrylate, hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate and 4-hydroxybutyl 2-methacrylate.

[0052] Preferably, the nonionic monomer is acrylonitrile and / or acrylamide. The nonionic monomer may also be an alkyl-substituted acrylamide monomer or a mixture thereof.

[0053] Preferably, the chain transfer agent is one or more of mercaptans, halogenated hydrocarbons and cobalt chelates.

[0054] More preferably, the chain transfer agent is mercaptan.

[0055] Preferably, the mercaptan is one or more of n-dodecyl mercaptan, n-octyl mercaptan, tert-dodecyl mercaptan, mercaptoethanol, isooctyl thioglycolate, 3-mercaptopropionic acid and 2-mercaptopropionic acid.

[0056] Preferably, the halogenated hydrocarbon is carbon tetrabromide and / or bromotrichloromethane.

[0057] Preferably, the molecular formula of the surfactant a2 is R [4-(l+m+n)] R 1 l R 2 m R 3 n N + X - , wherein R is a polymerizable group; R 1 , R 2 and R 3are alkyl or aryl groups having 1 to 20 carbon atoms; X - Cl - Br - , I - 、CH3OSO3 - and C2H5OSO3 - One or more of; l, m and n are 1 or 0 respectively;

[0058] The polymerizable group is an unsaturated alkenyl group polymerized by free radicals, and the unsaturated alkenyl group polymerized by free radicals is one or more of vinyl, allyl, acryloyl, methacryloyl, propenyl, 1,1-vinylidene and 1,2-vinylidene.

[0059] Surfactant a2 is a polymerizable surfactant, an ionic surfactant including a cationic group and a hydrophobic group and further having a polymerizable group;

[0060] in:

[0061] The cationic group can be preferably selected from the group consisting of primary ammonium salt ions, secondary ammonium salt ions, tertiary amine salt ions, and quaternary ammonium salt ions; the primary amine salt ions can be selected from the group consisting of alkyl ammonium salt ions RNH3 + ; The secondary ammonium salt ion can be selected from dialkylammonium ions R2NH2 + ; The tertiary ammonium salt ion can be selected from trialkylammonium ions R3NH + ; Quaternary ammonium salt ions can be selected as R4N + ; Wherein, R is a hydrophobic group, which can be selected from one or more of an alkyl group and an aryl group (phenyl, phenylene, etc.) having 1 to 20 carbon atoms, and can also have both an alkyl group and an aryl group;

[0062] The counter anion of the cationic group can be selected from Cl - Br - ,I - 、CH3OSO3 - 、C2H5OSO3 - ;

[0063] The polymerizable group is an unsaturated alkenyl group polymerized by free radicals, and can be selected from one or more of vinyl, allyl, acryloyl, methacryloyl, propenyl, 1,1-vinylidene and 1,2-vinylidene.

[0064] Further preferably, the surfactant a2 can be selected from one or more of dimethylaminoethyl octyl methacrylate hydrochloride, dimethylaminoethyl hexadecyl methacrylate hydrochloride, dimethylaminoethyl methacrylate decyl hydrochloride, dimethylaminoethyl dodecyl methacrylate hydrochloride, dimethylaminoethyl tetradecyl methacrylate hydrochloride, 11-acryloyloxyundecyltrimethylammonium bromide, 11-acryloyloxyundecyltriethylammonium bromide and methacryloyloxyethyl dodecyldimethylammonium bromide.

[0065] Preferably, the initiator a3 comprises an inorganic peroxide and / or an organic peroxide;

[0066] The inorganic peroxide is one or more of potassium persulfate, sodium persulfate, ammonium persulfate, hydrogen peroxide and percarbonate; wherein the percarbonate is preferably sodium percarbonate;

[0067] The organic peroxide is one or more of acyl peroxide, alkyl hydroperoxide, dialkyl peroxide and peroxyester.

[0068] Initiator a3 is a water-soluble initiator, which is used to generate free radicals to initiate vinyl polymerization and complete the free radical emulsion polymerization of the monomers.

[0069] Preferably, the acyl peroxide is benzoyl peroxide.

[0070] Preferably, the alkyl hydroperoxide is tert-butyl hydroperoxide and / or cumene hydroperoxide.

[0071] Preferably, the dialkyl peroxide is di-tert-butyl peroxide.

[0072] Preferably, the peroxyester is tert-butyl perbenzoate.

[0073] Preferably, the initiator a3 further comprises a reducing agent;

[0074] The reducing agent is one or more of sodium pyrosulfite, potassium pyrosulfite, sodium bisulfite, potassium bisulfite, sodium formaldehyde sulfoxylate, disodium 2-hydroxy-2-sulfinatoacetate, isoascorbic acid, azobisisobutyronitrile, 2,2'-azo-bis(2-methylbutyronitrile) and 4,4'-azobis(4-cyanovaleric acid).

[0075] In some cases, the above-mentioned inorganic peroxide or organic peroxide can form a redox initiation system with a suitable reducing agent, and an initiator that is distributed between the aqueous phase and the organic phase can be used, such as a combination of tert-butyl hydroperoxide and isoascorbic acid. The redox initiation system can reduce the heat required for generating free radicals, which is more suitable for the temperature required by the emulsion polymerization reaction system without affecting or destroying the emulsion polymerization reaction system.

[0076] Preferably, the cross-linking agent is a dihydrazide compound and / or a polyamine.

[0077] The crosslinking agent is used to react with the crosslinking monomers in the first monomer composition a1 and the second monomer composition b1, or to react with other olefin monomers in the second monomer composition b1. The crosslinking agent is preferably added after step S2, and more preferably after step S4.

[0078] Preferably, the dihydrazide compound is one or more of oxalic acid dihydrazide, malonic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, phthalic acid dihydrazide and terephthalic acid dihydrazide.

[0079] Preferably, the polyamine is isophorone diamine.

[0080] More preferably, the cross-linking agent is adipic acid dihydrazide.

[0081] Preferably, the reaction temperature of the emulsion polymerization may be 40 to 130° C., and more preferably 65 to 100° C. After the temperature of the mixture in the reactor reaches the reaction temperature, the initiator is added dropwise.

[0082] The second aspect of the present invention discloses an antibacterial soap-free polymer dispersion, which is prepared by any of the above methods for preparing an antibacterial soap-free polymer dispersion.

[0083] The third aspect of the present invention discloses an application of the antibacterial soap-free polymer dispersion as described above, wherein the antibacterial soap-free polymer dispersion is mixed with coating components to prepare a coating.

[0084] Preferably, the coating composition includes: pigments, such as titanium dioxide or carbon black; extenders, such as calcium carbonate, talc, clay, silica and silicates; fillers, such as glass or polymer microspheres, quartz and sand; thickeners; rheology modifiers; dyes; chelating agents; biocides; dispersants; antifreeze agents; plasticizers; adhesion promoters; coalescing agents; wetting agents; waxes; surfactants; slip additives; crosslinking agents; defoamers; colorants; preservatives; freeze / thaw protectants and corrosion inhibitors.

[0085] Coating additives may also be added to the coating including: co-solvents, reactive pigments, UV absorbers, antioxidants and stabilizers.

[0086] These coating ingredients and coating additives can be added in any order that does not cause incompatibility between the components; components insoluble in aqueous carriers (such as pigments and fillers) can be dispersed in polymer dispersions or aqueous carriers or co-solvents using a high shear mixer; these coating ingredients and coating additives can all be existing commercially available products.

[0087] The coating prepared from the antimicrobial soap-free polymer dispersion is a water-based coating that can be applied to a variety of surfaces, substrates or products, such as plastics, steel, aluminum, galvanized sheets, concrete, wood, bricks, masonry and gypsum boards; it can be applied to the desired substrate using conventional coating techniques, such as conventional spraying or airless spraying, roller coating, brushing, curtain coating, overcoating and dipping; generally, the coating can be cured at ambient temperature or dried by heating, depending on the substrate used.

[0088] Compared with the prior art, the present invention has the following beneficial effects:

[0089] 1. The antibacterial soap-free polymer dispersion prepared by the present invention does not contain free emulsifiers, and the gloss, water resistance, chemical resistance and adhesion of the polymer emulsion are significantly improved; the solid content is high, the production efficiency is high, and the film-forming time is short; no amine neutralizer is used, and the polymer dispersion is odorless. The antibacterial monomer used is a non-ionic monomer containing a nitrogen heterocycle. The prepared antibacterial coating has a strong killing ability against microorganisms such as methicillin-resistant Staphylococcus aureus, fungi, Mycobacterium tuberculosis, hydrophilic viruses and bacterial spores, and still has a strong bactericidal effect after the surface is cleaned with an anionic detergent, and has the characteristics of long-lasting antibacterial.

[0090] 2. Connect the antibacterial monomer to the coating resin by polymerization, so that it can prevent migration and loss, and achieve long-term stability and long-term protective bactericidal ability; nitrogen-containing heterocyclic antibacterial functional olefin monomers are non-salt antibacterial monomers, which act similarly to antimicrobial peptides, acting on the cell membrane, forming transmembrane ion channels on the membrane, destroying the integrity of the membrane, and causing leakage of cell contents, which can effectively kill cells.

[0091] 3. By controlling the average particle size of the prepared polymer dispersion to be at a smaller level, it can have excellent stability and can prepare an emulsion with a high solid content without agglomeration; at the same time, it also has a suitable glass transition temperature Tg and can be used at low temperatures.

[0092] 4. The water-based paint prepared by the polymer dispersion prepared by the present invention has an antibacterial rate of more than 99% against Staphylococcus aureus and Escherichia coli according to the standard of HG / T 3950 2007; after the paint film is scrubbed with an anionic surfactant, the antibacterial rate can still reach more than 99%; in addition, other properties of the water-based paint can also meet the requirements or standards of enterprises, and the water-based paint is an antibacterial paint with good performance, which can be used in automotive interiors, household appliances, medical equipment, wood, etc. DETAILED DESCRIPTION

[0093] The present invention is described in detail below with reference to specific embodiments, but this is by no means a limitation of the present invention.

[0094] Unless otherwise specified, the reagents used in the following examples may be commercially available products that can be routinely obtained by those skilled in the art.

[0095] Table 1 below lists the corresponding names and classifications of the compounds used in various examples and comparative examples.

[0096] Table 1 Classification of compounds used in Examples and Comparative Examples

[0097]

[0098]

[0099] Example 1

[0100] The operation was carried out in a 5 L jacketed reactor equipped with a stirring blade, a reflux condenser and a temperature regulation system.

[0101] The monomer composition, the initiator aqueous solution and the reducing agent aqueous solution are continuously added into the reactor by controlling the flow rate through a metering pump.

[0102] First, according to the component ratios in Table 2, a surfactant was mixed with the first monomer composition a1 to prepare a premixed solution, and then mixed to prepare the second monomer composition b2. 0.5 parts by mass of APS was used to prepare a 10 wt% APS aqueous solution, 0.2 parts by mass of sodium pyrosulfite was used to prepare a 10 wt% sodium pyrosulfite aqueous solution, and 1.2 parts by mass of AADH was used to prepare a 20 wt% AADH aqueous solution.

[0103] Add the pre-charged materials in the proportions in Table 2 to the reactor at room temperature, then heat to 80°C, add 5wt% of the premixed liquid, and then add 40wt% of the APS aqueous solution. After waiting for 10 minutes, add all the remaining premixed liquid dropwise into the reactor over 4.5 hours, and then keep warm for 45 minutes. Then cool the reaction medium to 65°C, and add 20wt% of the second monomer composition b2 over 5 minutes. After waiting for 5 minutes, add all the remaining second monomer composition b2, 30wt% of the APS aqueous solution, and 50wt% of the sodium pyrosulfite aqueous solution to the reactor at the same time over 105 minutes. After all the above substances are added, add all the remaining APS aqueous solution and sodium pyrosulfite aqueous solution to the reactor over 60 minutes. After the addition is complete, cool the reaction medium to 40°C, and then add the AADH aqueous solution. Wait for 10 minutes and discharge the product from the reactor.

[0104] Example 2

[0105] The preparation method is the same as that in Example 1, and the amounts of each substance used are shown in Table 2.

[0106] Compared with Example 1, the main difference is that the polymeric cationic surfactant AUTMAB is replaced by the polymeric cationic surfactant MEDDAB to change the properties of the surfactant.

[0107] Example 3

[0108] The preparation method is the same as that in Example 1, and the amounts of each substance used are shown in Table 2.

[0109] Compared with Example 2, the main feature of the invention is that the antibacterial monomer N-thiolated β-lactam derivative LD is replaced by the antibacterial monomer quinoline derivative QD to change the properties of the antibacterial monomer.

[0110] Example 4

[0111] The preparation method is the same as that in Example 1, and the amounts of each substance used are shown in Table 2.

[0112] Compared with Example 2, the main difference is that the antibacterial monomer N-thiolated β-lactam derivative LD is replaced by the antibacterial monomer sulfamethoxazole derivative AMBS to change the properties of the antibacterial monomer.

[0113] Comparative Example 1

[0114] The preparation method is the same as that in Example 1, and the amounts of each substance used are shown in Table 2.

[0115] Compared with Example 1, the main feature of the invention is that the antibacterial monomer N-thiolated β-lactam derivative LD is replaced by the cationic antibacterial monomer PEDAB to change the properties of the antibacterial monomer.

[0116] Comparative Example 2

[0117] The preparation method is the same as that in Example 1, and the amounts of each substance used are shown in Table 2.

[0118] Compared with Example 1, the Tg of the dispersion is increased mainly by increasing the amounts of MMA and ST and reducing the amount of BuA.

[0119] Comparative Example 3

[0120] The preparation method is the same as that in Example 1, and the amounts of each substance used are shown in Table 2.

[0121] Compared with Example 1, the main change is that the polymeric cationic surfactant AUTMAB is replaced by the non-polymeric cationic surfactant DC to change the properties of the surfactant.

[0122] Table 2 Content of each substance in Examples 1 to 4 and Comparative Examples 1 to 3 (in parts by mass)

[0123]

[0124]

[0125] In the above table, DIW is deionized water.

[0126] Basic performance test:

[0127] The performance of the antibacterial polymer dispersions prepared in Examples 1 to 4 and Comparative Examples 1 to 3 was tested, and the test standards were as follows:

[0128] MFT: A 25 μm wet film was prepared using a scraper and the MFT was measured in a Rhopoint MFT-Bar90 in the temperature range of 0°C to 90°C. The MFT is the lowest temperature at which the film does not show cracking.

[0129] Particle size: The particle size was measured by dynamic light scattering using a Malvern Zatasizer model Nano-S90, and the average hydrodynamic diameter Z-mean was used as the particle size value;

[0130] Rotational viscosity: The rotational viscosity was measured at 23±1°C using an Anton Paar MCR92 rheometer.

[0131] The test results are shown in Table 3.

[0132] Table 3 Performance test results of polymer dispersions prepared in Examples 1 to 4 and Comparative Examples 1 to 3

[0133]

[0134] Application Examples 1 to 6

[0135] The polymer dispersions prepared in Examples 1 to 4 and Comparative Examples 1 to 2 were prepared according to the ratios in Table 4 to obtain antibacterial water-based coatings.

[0136] The antibacterial polymer dispersion prepared above, water and various components according to the proportions in Table 4 were added into the container of a disperser under high-speed stirring and ground to a fineness of less than 10 μm.

[0137] Table 4 Water-based coating formula ratio of application examples 1 to 6

[0138] Components effect Mass Deionized water Thinner 37.4 Antimicrobial polymer dispersions Main resin 50 Butyl diethylene glycol Co-solvent 5 Surfynol 104 DPM Wetting Agents 0.5 BYK333 Dispersants 0.8 Borchi Gel L75N Thickener 1.3 Dowanol PnP Coagulant 5 total / 100

[0139] Paint film performance test:

[0140] The water-based coatings prepared according to Examples 1 to 6 were tested for physical properties and chemical resistance, and the test standards are as follows:

[0141] Pencil hardness: GB / T 6739-2006;

[0142] Adhesion: GB / T 9286-1998;

[0143] Chemical resistance: Use RJCS solvent resistance wiper (Shanghai Modern Environmental Engineering Technology Co., Ltd.): record the number of times the absorbent cotton soaked in MEK is wiped back and forth on the paint film surface, one reciprocating wipe counts as one time, until the paint film shows any peeling, shedding, or damage;

[0144] Water resistance: A wet film with a thickness of 200 μm was coated on a glass plate and then dried in a climate-controlled room (23±1°C and 50±5% RH) for 7 days. The coated glass plate was then immersed in 40°C water for 10 days, and the appearance was observed and the adhesion was tested.

[0145] The test results are shown in Table 5.

[0146] Table 5 Performance test results of water-based coatings in application examples 1 to 6

[0147]

[0148] Antibacterial performance test:

[0149] Antibacterial performance: The antibacterial rate of the coating against Staphylococcus aureus and Escherichia coli was determined according to HG / T 3950 2007 standard.

[0150] The antibacterial rate of the coating against Staphylococcus aureus and Escherichia coli was measured according to the HG / T 3950 2007 standard. The test results show that the antibacterial rate of the coating prepared by using the polymer dispersions in Examples 1 to 4 and Comparative Example 1 can reach more than 99%. After the paint film was scrubbed with anionic surfactants, the antibacterial rate of the coating prepared by using the polymer dispersions in Examples 1 to 4 can still reach more than 99%, while the antibacterial rate of the coating prepared by using the polymer dispersion in Comparative Example 1 is less than 90%. This is because the coating prepared by the polymer dispersions in Examples 1 to 4 containing non-ionic nitrogen heterocyclic monomers can maintain high antibacterial performance in the presence of anions.

[0151] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for preparing an antibacterial soap-free polymer dispersion, characterized in that: The steps include: S1: mixing a first monomer composition a1, a surfactant a2 and an initiator a3 to obtain an emulsion A; S2: subjecting the emulsion A obtained in step S1 to emulsion polymerization to obtain a first polymer particle dispersion P1; S3: adding the second monomer composition b1 to the first polymer particle dispersion P1 obtained in step S2 to obtain a mixture B; S4: subjecting the mixture B obtained in step S3 to emulsion polymerization to obtain a second polymer particle dispersion P2; S5: adding a crosslinking agent to the second polymer particle dispersion P2 obtained in step S4 to obtain the antibacterial soap-free polymer dispersion; in, The first monomer composition a1 comprises a nitrogen-containing heterocyclic olefin monomer, a crosslinking monomer, other olefin monomers and a chain transfer agent; the other olefin monomers are butyl acrylate, styrene and acrylamide; The second monomer composition b1 includes a nitrogen-containing heterocyclic olefin monomer and other olefin monomers; the other olefin monomers are methyl methacrylate and styrene; The nitrogen-containing heterocyclic olefin monomer is a non-salt antibacterial monomer, and is one or more of N-thiol β-lactam derivatives, quinoline derivatives and sulfamethoxazole derivatives, and is selected from one or more of the compounds of the following formulas I to VIII: Formula I; Formula II; Formula III; Formula IV; Formula V; Formula VI; Formula VII; Formula VIII.

2. The method for preparing an antibacterial soap-free polymer dispersion according to claim 1, characterized in that: The first monomer composition a1 comprises 1 to 20 parts by weight of a nitrogen-containing heterocyclic olefin monomer, 1 to 20 parts by weight of a crosslinking monomer, 50 to 99 parts by weight of other olefin monomers, and 0.05 to 1 parts by weight of a chain transfer agent; The second monomer composition b1 comprises 1 to 10 parts by weight of a nitrogen-containing heterocyclic olefin monomer and 10 to 50 parts by weight of other olefin monomers; The amount of the surfactant a2 is 0.05-5wt% of the first monomer composition a1; The amount of the initiator a3 is 0.05-5wt% of the first monomer composition a1; The amount of the second monomer composition b1 is 15-85wt% of the total amount of the first monomer composition a1 and the second monomer composition b1; The average particle size of the first polymer particle dispersion P1 is less than 90 nm, and the other olefin monomers in the first monomer composition a1 are composed of 58 parts by mass of butyl acrylate, 13.5 parts by mass of styrene and 0.5 parts by mass of acrylamide; The second polymer particle dispersion P2 has a solid content of 40-70%, an average particle size of less than 150 nm, wherein the content of polymer particles with a particle size greater than 100 nm is less than 25 wt %. The other olefin monomers in the second monomer composition b1 consist of 15 parts by mass of methyl methacrylate and 5 parts by mass of styrene.

3. The method for preparing an antibacterial soap-free polymer dispersion according to claim 1 or 2, characterized in that: In the first monomer composition a1: The crosslinking monomer is one or more of allyl methacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, trimethylolpropane triacrylate, divinylbenzene, dicyclopentenyl acrylate, glycidyl methacrylate, acetoacetoxyethyl methacrylate, acrolein, methacrolein, diacetone acrylamide, isocyanatoethyl methacrylate and 3-isopropenyl-α,α-dimethylbenzyl isocyanate; The chain transfer agent is one or more of mercaptan, halogenated hydrocarbon and cobalt chelate.

4. The method for preparing an antibacterial soap-free polymer dispersion according to claim 1, characterized in that: The molecular formula of the surfactant a2 is R [4-(l+m+n)] R 1 l R 2 m R 3 n N + X - , wherein R is a polymerizable group; R 1 , R 2 and R 3 are alkyl or aryl groups with 1 to 20 carbon atoms; X - Cl - Br - ,I - 、CH3OSO3 - and C2H5OSO3 - One or more of; l, m and n are 1 or 0 respectively; The polymerizable group is an unsaturated alkenyl group polymerized by free radicals, and the unsaturated alkenyl group polymerized by free radicals is one or more of vinyl, allyl, acryloyl, methacryloyl, propenyl, 1,1-vinylidene and 1,2-vinylidene.

5. The method for preparing an antibacterial soap-free polymer dispersion according to claim 1, characterized in that: The initiator a3 includes inorganic peroxide and / or organic peroxide; The inorganic peroxide is one or more of potassium persulfate, sodium persulfate, ammonium persulfate, hydrogen peroxide and sodium percarbonate; The organic peroxide is one or more of acyl peroxide, alkyl hydroperoxide, dialkyl peroxide and peroxyester.

6. The method for preparing an antibacterial soap-free polymer dispersion according to claim 5, characterized in that: The initiator a3 also includes a reducing agent; The reducing agent is one or more of sodium pyrosulfite, potassium pyrosulfite, sodium bisulfite, potassium bisulfite, sodium formaldehyde sulfoxylate, disodium 2-hydroxy-2-sulfinyl acetate and isoascorbic acid.

7. The method for preparing an antibacterial soap-free polymer dispersion according to claim 1, characterized in that: The cross-linking agent is a dihydrazide compound and / or a polyamine.

8. The method for preparing an antibacterial soap-free polymer dispersion according to claim 1, characterized in that: The reaction temperature of the emulsion polymerization is 40-130°C.

9. An antibacterial soap-free polymer dispersion, characterized in that: The antibacterial soap-free polymer dispersion is prepared by the preparation method of any one of claims 1 to 8.

10. Use of the antibacterial soap-free polymer dispersion according to claim 9, characterized in that: The antibacterial soap-free polymer dispersion is mixed with coating components to prepare the coating.

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