Anti-graffiti acrylic emulsion and preparation method and application thereof

Abstract

The application discloses an anti-graffiti acrylic emulsion and a preparation method and application thereof. The emulsion is prepared by emulsion polymerization of the following monomer components in a weight ratio and then obtained by stripping: a) 15-70% of ester monomers; b) 1.3-10% of acetoacetoxy-containing olefinically unsaturated monomers; c) 0.5-5% of unsaturated hydrophilic monomers; d) 0.2-5% of reactive silane coupling agents; e) 10-50% of styrene; and f) 14-25% of TMS-protected alkynyl monomers. The total mass of components a), b), c), d), e) and f) is 100%. The TMS-protected alkynyl monomers are added in the emulsion, can be deprotected and further undergo alkynyl addition reaction in the high-temperature stripping process after reaction, so that the polymer chain segments are intertwined and connected, a compact cross-linked structure is formed, and the anti-graffiti capability of the paint is greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to an acrylic emulsion, in particular to an anti-graffiti acrylic emulsion and a preparation method and application thereof. BACKGROUND

[0002] With the gradual improvement of people's living standards, people's requirements for interior decorative coatings are also gradually increasing. The traditional interior wall coating is relatively single, and gradually cannot meet people's growing demand for coating diversity. Colorful and multi-shaped artistic coatings have emerged as the times require.

[0003] Artistic coatings have the defects of easy falling off and easy pollution when used as a decorative surface of an indoor wall, which is not conducive to use in an environment prone to pollution, especially in a children's room with children, the coating surface is more easily contaminated by daily stains such as watercolor pens, etc. The general solution is to use a layer of anti-graffiti finish coating on the surface of the artistic coating.

[0004] The anti-graffiti finish coatings on the market are divided into single-component anti-graffiti coatings and two-component anti-graffiti coatings. The anti-graffiti effect of the two-component anti-graffiti coating is better, but since the two-component coating is mainly composed of high-viscosity substances such as polyurethane and epoxy resin, it usually needs to be dispersed using a solvent, so the odor is large, and the price is expensive, which greatly limits its development. Compared with the single-component anti-graffiti, the construction is convenient, but there are problems to be solved, such as relatively poor anti-graffiti effect and low gloss.

[0005] Patent CN111363081A improves the hydrophobicity of the paint film by using a large amount of hydrophobic monomers for polymerization, effectively improving the watercolor pen resistance of the coating, but also brings the problem of too high film forming temperature, which needs to introduce a large amount of film forming aids, which brings great challenge to the odor of the coating. SUMMARY

[0006] In order to solve the above technical problems, the present application provides an anti-graffiti acrylic emulsion and a preparation method and application thereof.

[0007] According to one aspect of the present application, an anti-graffiti acrylic emulsion is first provided, which contains a TMS-protected alkynyl monomer. The alkynyl monomer contains a TMS protective group, which can prevent the alkynyl group from participating in the reaction to generate undesirable by-products during the emulsion polymerization reaction, and the alkynyl monomer can be deprotected and further undergo alkynyl addition reaction during the high-temperature stripping process after the reaction, so that the polymer chains are intertwined and connected, forming a dense cross-linked structure, thereby greatly improving the anti-graffiti ability of the coating.

[0008] According to another aspect of the present application, there is also provided a method for preparing the anti-graffiti acrylic emulsion. The emulsion is prepared by a conventional emulsion polymerization method and stripped to remove VOC after the reaction is completed. During the stripping process, the high temperature promotes the addition reaction of the alkynyl group, so that the polymer segments are intertwined and connected to form a dense cross-linked structure, thereby greatly improving the anti-graffiti ability of the coating.

[0009] According to another aspect of the present application, there is also provided the use of the anti-graffiti acrylic emulsion in a coating.

[0010] To achieve the above object, the technical scheme adopted by the present application is as follows:

[0011] An anti-graffiti acrylic emulsion is prepared by emulsion polymerization of the following monomer components in a weight ratio and then stripped:

[0012] a) 15-70%, preferably 44-66%, of ester monomers;

[0013] b) 1.3-10%, preferably 2-4%, of ethacryloyl group-containing olefinically unsaturated monomers;

[0014] c) 0.5-5%, preferably 1-5%, of unsaturated hydrophilic monomers;

[0015] d) 0.2-5%, preferably 0.5-2%, of reactive silane coupling agents;

[0016] e) 10-50%, preferably 20-30%, of styrene;

[0017] f) 14-25%, preferably 10-15%, of TMS-protected alkynyl monomers;

[0018] wherein the total mass of components a), b), c), d), e), and f) is 100%.

[0019] In a preferred embodiment of the present application, component a) is selected from the group consisting of alkyl acrylate, allyl ester, vinyl acetate, and methyl-substituted versions thereof having 1-16 carbon atoms, preferably selected from the group consisting of alkyl acrylate, vinyl acetate, and methyl-substituted versions thereof having 1-8 carbon atoms, and more preferably selected from one or more of methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, 2-methylpropyl methacrylate, isoamyl methacrylate, and heptyl methacrylate;

[0020] Preferably, component b) is selected from one or more of acetoacetoxy ethyl acrylate, acetoacetoxy propoxy acrylate, acetoacetoxy butoxy acrylate, acetoacetyl vinyl ester, acetoacetyl allyl ester, and methyl-substituted versions thereof, preferably one or both of acetoacetoxy ethyl acrylate and acetoacetyl allyl ester;

[0021] Preferably, component c) is selected from unsaturated monomers containing a hydrophilic group selected from carboxyl, hydroxyl, amido, sulfonic acid, phosphate, ureido, sulfonate, sulfate, phosphate; preferably component c) is one or more of acrylic acid, methacrylic acid, hydroxyethyl acrylate, acrylamide, methacrylamide, ethyl ethylene urea, vinyl alkoxy phosphate, sodium 2-acrylamido-2-methylpropane sulfonate;

[0022] Preferably, component d) is selected from silane coupling agents containing a vinyl or epoxy functional group, preferably one or more of vinyl trimethoxysilane, gamma-methacryloxypropyl trimethoxysilane, gamma-glycidoxypropyl trimethoxysilane, mercaptopropyl trimethoxysilane.

[0023] In one preferred embodiment of the present application, component f) has the structural formula of Formula I:

[0024]

[0025] In the present application, the preparation process of component f) of Formula I does not have any limiting effect on its role in the present application, and those skilled in the art can simply synthesize and prepare component f) of Formula I according to, for example, the following synthesis process, which specifically includes:

[0026]

[0027] A, reacting N-(2-hydroxyethyl) maleimide and maleic anhydride to form product A;

[0028] B, reacting product A with trimethylsilyl propargyl alcohol to form TMS-protected alkynyl monomer of Formula I.

[0029] In step A of the above synthesis process, the molar ratio of N-(2-hydroxyethyl) maleimide to maleic anhydride is 1:(1.2-1.5).

[0030] Further, the reaction conditions of step A are a reaction temperature of 25-65°C and a reaction time of 12-40h.

[0031] In step B of the above synthesis process, the molar ratio of product A to trimethylsilyl propargyl alcohol is (2-3):1.

[0032] Further, the reaction conditions of step B are that the reaction temperature is 25-65℃, and the reaction time is 12-40h.

[0033] The component shown in the above formula I contains maleimide group and TMS-protected alkynyl group at the same time, wherein the maleimide group can participate in the reaction as a monomer in the polymerization process, thereby introducing the TMS-protected alkynyl group into the polymer molecular chain segment; and the TMS-protected alkynyl group is stable in the low-temperature polymerization process and does not participate in the reaction to generate undesirable by-products and the like, and is removed from the protection and rapidly reacts in the high-temperature stripping process after the polymerization is completed, so that the polymer chain segment connected therewith is further wound and connected to form a dense cross-linked structure, thereby greatly improving the anti-graffiti ability of the emulsion when used as a coating.

[0034] In a preferred scheme of the present application, the preparation raw materials of the emulsion further optionally include an emulsifier, an initiator, a neutralizing agent, a post-treatment agent, a pH regulator, water.

[0035] In a preferred scheme of the present application, the emulsifier is selected from one or more of sodium dodecyl sulfate, sodium p-styrenesulfonate, sodium dodecyl benzene sulfonate, alcohol ether sulfosuccinate, alkyl alcohol ether sulfate, alkyl alcohol ether phosphate, preferably sodium dodecyl sulfate and / or sodium dodecyl benzene sulfonate;

[0036] Preferably, the amount of the emulsifier is 1-5%, preferably 1-2%, of the total mass of components a)-f);

[0037] The initiator is selected from one or more of sodium persulfate, potassium persulfate, ammonium persulfate, preferably sodium persulfate and / or potassium persulfate;

[0038] Preferably, the total amount of the initiator is 0.2-0.6%, preferably 0.2-0.4%, of the total mass of components a)-f);

[0039] The neutralizing agent is selected from one or more of sodium bicarbonate, diethylene triamine, diethanolamine, ethanolamine, preferably sodium bicarbonate;

[0040] Preferably, the amount of the neutralizing agent is 0.1-4%, preferably 0.1-0.3%, of the total mass of monomer components a)-f);

[0041] The post-treatment agent includes an oxidizing agent and / or a reducing agent, the oxidizing agent is selected from one or more of tert-butyl peroxide, hydrogen peroxide, sodium persulfate, potassium persulfate, ammonium persulfate, preferably tert-butyl peroxide and / or hydrogen peroxide; and the reducing agent is selected from one or more of sodium bisulfite, sodium metabisulfite, vitamin C, preferably sodium bisulfite and / or sodium metabisulfite;

[0042] Preferably, the total amount of the post-treatment agent is 0.15-0.6%, preferably 0.2-0.4% of the total mass of components a)-f);

[0043] The pH regulator is selected from one or more of diethylene triamine, diethanol amine, ethanol amine, preferably diethylene triamine and / or ethanol amine;

[0044] Preferably, the end point of the addition of the pH regulator is to adjust the pH of the system to 7-9;

[0045] Preferably, the total amount of water is 1-1.5 times, preferably 1-1.3 times the total mass of components a)-f).

[0046] The acrylic emulsion of the present application contains strong alkynyl crosslinking points, and the crosslinking method belongs to chemical crosslinking, which is much higher than the physical crosslinking (such as hydrogen bond) method, so that water and stains are difficult to enter the paint film structure, thus having super-hydrophobicity, resisting watercolor pen stains, realizing the water-erasable watercolor pen stain performance similar to whiteboard, and having good gloss and water resistance, which effectively improves the watercolor pen performance of the single-component anti-graffiti paint.

[0047] The acrylic emulsion prepared by the present application has a solid content of 41-45%, a pH of 7-9, and an emulsion particle size of 69-80 nm.

[0048] Based on another aspect of the present application, a preparation method of the anti-graffiti acrylic emulsion is provided, which comprises the following steps:

[0049] 1) uniformly mix components a), b), c), d), e), f) and water, and part of the emulsifier to prepare a pre-emulsion;

[0050] 2) dissolve the initiator in water in two parts to obtain a dropwise added initiator and a bottom initiator;

[0051] 3) mix the neutralizing agent, the remaining emulsifier and water, and then add them into a reaction kettle, fully stir, and heat to 80-90 DEG C; add part of the pre-emulsion, uniformly stir, then add all of the bottom initiator, react for 10-20 min, and prepare a seed emulsion;

[0052] 4) control the temperature in the reaction kettle to be 80-90 DEG C, continue to add the remaining pre-emulsion and all of the dropwise added initiator to the seed emulsion, the feeding time is 2-4 h, and then keep warm for 20-60 min;

[0053] 5) cool the reaction kettle to 70-80 DEG C, gradually add the post-treatment agent to the reaction kettle, the feeding time is 2-4 h, and then keep warm for 30-60 min;

[0054] 6) cooling to below 45℃, adding pH regulator to adjust the pH of the system to 7-9, stripping, filtering and discharging.

[0055] In one preferred embodiment of the present application, the amount of emulsifier used in step 1) is 90-99.5% of the total mass of emulsifier.

[0056] Preferably, the amount of water used in step 1) is 25-35% of the total mass of water.

[0057] In one preferred embodiment of the present application, the amount of initiator used to prepare the dropwise initiator in step 2) is 25-50% of the total mass of initiator, and the amount of initiator used to prepare the bottom initiator is 50-75% of the total mass of initiator.

[0058] Preferably, the amount of water used to prepare the dropwise initiator in step 2) is 1-6% of the total mass of water, and the amount of water used to prepare the bottom initiator is 1-6% of the total mass of water.

[0059] Preferably, the amount of pre-emulsion used to prepare the seed emulsion in step 3) is 1-8% of the total mass of pre-emulsion.

[0060] In one preferred embodiment of the present application, the stripping temperature in step 6) is 55-85℃, and the pressure is controlled at -75Kpa to -95Kpa.

[0061] Based on another aspect of the present application, there is also provided a use of the anti-graffiti acrylic emulsion as described above or prepared by the method as described above in a coating.

[0062] The acrylic emulsion of the present application has good film-forming effect without the addition of film-forming aids, and has low MFFT, excellent resistance to scrubbing and freeze-thaw stability, low VOC content, good environmental performance, and other advantages, and is particularly suitable for use in the field of interior wall coatings.

[0063] The acrylic emulsion provided by the present application is a water-based emulsion, has low VOC, is safe and environmentally friendly, has excellent anti-graffiti performance, and is easy to apply. DETAILED DESCRIPTION

[0064] The present application will be further described below through specific examples, which are only used to illustrate the present application and do not limit the scope of the present application.

[0065] The raw materials used in the following examples are shown in Table 1, and other ordinary commercially available raw materials are used unless otherwise specified:

[0066] Table 1, raw material information

[0067]

[0068]

[0069] The following processing procedures were used in the following examples:

[0070] Stripping: The emulsion was preheated to 55°C in a buffer tank, and then was fed into a stripping column for stripping (stripping temperature 55°C); wherein the emulsion was fed at the top of the column, air and steam were fed at the bottom of the column, and the two were countercurrently contacted, mixed at high speed for a short time, and the VOC components were separated from the emulsion through a vacuum tail gas pipeline with steam and air as the entraining agents, and the emulsion was discharged at the bottom. During the stripping process, the relative flow rates of air, steam and emulsion were 1:0.5:10.

[0071] Watercolor pen resistance evaluation: 100 μm wet film was scraped on black and white paper, dried at room temperature for 1 day, and then a line was drawn with a Morning 12-color washable watercolor pen, and the erasing was observed after wiping with a wet cloth immediately, after 1 day and after 3 days, respectively. The evaluation criteria were as follows:

[0072] 5 points: all erased.

[0073] 4 points: all erased except for the red color containing solvent, and the red pen left a slight mark.

[0074] 3 points: all erased except for the red color containing solvent, and the red pen left a clear mark.

[0075] 2 points: the watercolor pen left a slight mark, and the red pen left a clear mark.

[0076] 1 point: the watercolor pen left a clear mark.

[0077] 0 points: the paint film was damaged and completely erased.

[0078] Paint film gloss evaluation: The gloss resistance of the paint film was tested according to HG / T 5065-2016.

[0079] Water resistance evaluation: The water resistance of the latex paint was determined according to HG / T 5065-2016.

[0080] VOC: The volatile substances with a boiling point lower than 250°C were tested according to GB / T 18582.

[0081] SVOC: The volatile substances with a boiling point of 250-400°C were tested according to GB / T 18582.

[0082] Olfactory grade: 10 people were randomly selected as the scoring standard, and the odor of the same sample was scored, wherein:

[0083] 0 points: no odor

[0084] 1 point: slight odor, difficult to detect.

[0085] 2 points: slight odor, pleasant odor.

[0086] 3 points: slight odor, pungent odor.

[0087] 4 points: very obvious odor.

[0088] 5 points: very obvious odor and dizziness and other discomfort.

[0089] Washing resistance: according to HG / T 5065-2016 to test the washing resistance of the paint film.

[0090]

Preparation of Examples

[0091] The TMS-protected alkynyl monomer, denoted as Q, was prepared according to the following method:

[0092]

[0093] A, reacting N-(2-hydroxyethyl)maleimide and maleic anhydride in a molar ratio of 1:1.2 to form product A; reaction temperature 30°C, reaction time 12h;

[0094] B, reacting product A with trimethylsilyl propargyl alcohol in a molar ratio of 2:1 to form the TMS-protected alkynyl monomer shown in formula I; reaction temperature 30°C, reaction time 12h.

[0095]

Example 1

[0096] Prepare each raw material according to the following formulation:

[0097] a) 609g of BA

[0098] b) 38g of AAEM

[0099] c) 14g of AA

[0100] d) 5g of A171

[0101] e) 167g of styrene

[0102] f) 167g of TMS-protected alkynyl monomer Q.

[0103] Prepare emulsifier SDS 9.19g, SSS 9g, initiator APS 3g, neutralizer sodium bicarbonate 2g, post-treatment agent (t-BHP 2g and 5% aqueous sodium bisulfite solution 40g), water 1323g, pH adjuster diethylenetriamine.

[0104] Prepare the acrylic emulsion according to the following method:

[0105] 1) Mix components a), b), c), d), e), f) and 43 3g water, 9g emulsifier SDS, 9g emulsifier SSS uniformly to prepare a pre-emulsion;

[0106] 2) Mix 1g initiator APS with 38g water to obtain a dropping initiator; mix 2g initiator APS with 21g water to obtain a bottom initiator;

[0107] 3) Mix 2g sodium bicarbonate, 0.19g emulsifier SDS and 831g water, then add to the reaction kettle, stir well, and heat to 85°C; add 50g pre-emulsion, stir uniformly, then add all the bottom initiator, react for 10min, to prepare a seed emulsion;

[0108] 4) Control the temperature in the reaction kettle at 85°C, continue to add the remaining pre-emulsion and all the dropping initiator to the seed emulsion, total dropping time 4h, then keep for 2min;

[0109] 5) Cool the reaction kettle to 75°C, gradually add post-treatment agent (t-BHP 2g and 5% sodium bisulfite aqueous solution 40g) to the reaction kettle, feeding time 2h, then keep for 30min;

[0110] 6) Cool to below 45°C, add pH regulator diethylenetriamine to adjust the pH of the system to 8, strip, filter through a 100 mesh screen, and discharge.

[0111]

Example 2-8

[0112] Prepare an acrylic emulsion according to the substantially same method as Example 1, the only difference being that the raw material selection and amount in Table 2 are different; at the same time, ensure that in step 3), the addition amount of the pre-emulsion accounts for 5% of the total mass.

[0113]

Comparative Example 1

[0114] Prepare an acrylic emulsion according to the substantially same method as Example 1, the only difference being that component f is not added.

[0115]

Comparative Example 2

[0116] Prepare an acrylic emulsion according to the substantially same method as Example 1, the only difference being that component f is replaced by monomer X prepared by the following process:

[0117]

[0118] React N-(2-hydroxyethyl)maleimide and maleic anhydride with a molar ratio of 1:1.2 to generate monomer X; reaction temperature 30°C, reaction time 12h.

[0119] Comparative Example 3

[0120] The acrylic emulsion was prepared according to the substantially same method as Example 1, except that component f was replaced by the same mass of trimethylsilyl propargyl alcohol.

[0121] The acrylic emulsion prepared in each example was used to prepare paint according to the formulation in Table 3, and the paint film performance tests such as water-based marker resistance, water resistance, gloss, etc. were carried out, and the results are shown in Table 4. The acrylic emulsion prepared in each comparative example was used to prepare paint according to the formulation in Table 3, and the paint film performance tests such as water-based marker resistance, water resistance, gloss, etc. were carried out, and the results are shown in Table 5.

[0122] As shown in Tables 4-5, the performance test results of the paint prepared by the emulsion in the examples of the present application all meet the requirements of children's room paint in “GB / T 34676-2017 Interior Wall Coatings for Children's Room Decoration”, and the film-forming property and freeze-thaw stability are both obviously improved.

[0123] From the above test results, it can be seen that the emulsion formula provided by the present application has a synergistic enhancing effect on the low-temperature film-forming property, scrub resistance and freeze-thaw stability of the paint, and has low VOC content and low emulsion odor; by introducing the TMS-protected alkynyl monomer, the water-based marker resistance of the emulsion is obviously improved.

[0124] Table 2, raw material selection and amount in Examples 1-8 (unit: g)

[0125]

[0126]

[0127] Table 3, paint formulation

[0128]

[0129] Table 4, performance test results of the paint obtained from the emulsion in the examples

[0130]

[0131] Table 5, performance test results of the paint obtained from the emulsion in the comparative examples

[0132] Comparative Example 1 Comparative Example 2 Comparative Example 3 State in the container of the finish coating No caking No caking No caking Workability of the finish coating Good Good Good Appearance of the coating film Normal Normal Normal Drying time of the paint film (tack-free, h) 2h 2h 2h Resistance to watercolor pens 1 1 1 Water resistance Passed, no whitening and blistering Passed, no whitening and blistering Passed, no whitening and blistering Gloss / ° (refractive angles 20° / 60° / 85°) 6.2 / 65 / 73 6.2 / 61 / 75 6.3 / 60 / 53 VOC < 500 ppm < 500 ppm < 500 ppm SVOC < 500 ppm < 500 ppm < 500 ppm Olfactory grade 1 1 1 Resistance to scrubbing performance (times) 1628 1298 2000

Claims

1. An anti-graffiti acrylic emulsion, characterized in that, The emulsion is prepared by emulsion polymerization followed by stripping of the monomer components in the following weight ratios: a) 15-70% ester monomers; b) 1.3-10% of olefinic unsaturated monomers containing acetoacetic acid groups; c) 0.5-5% unsaturated hydrophilic monomers; d) 0.2-5% reactive silane coupling agent; e) 10-50% styrene; f) 14-25% TMS-protected alkynyl monomers; The total mass of components a), b), c), d), e), and f) is 100%.

2. The anti-graffiti acrylic emulsion according to claim 1, characterized in that, The emulsion is prepared by emulsion polymerization followed by stripping of the monomer components in the following weight ratios: a) 44-66% ester monomers; b) 2-4% of olefinic unsaturated monomers containing acetoacetic acid groups; c) 1-5% unsaturated hydrophilic monomers; d) 0.5-2% reactive silane coupling agent; e) 20-30% styrene; f) 10-15% TMS-protected alkynyl monomers; The total mass of components a), b), c), d), e), and f) is 100%.

3. The anti-graffiti acrylic emulsion according to claim 1, characterized in that, Component a) is selected from alkyl acrylates, allyl acrylates, vinyl acetates and their methyl-substituted derivatives having 1-16 carbon atoms.

4. The anti-graffiti acrylic emulsion according to claim 3, characterized in that, Component a) is selected from alkyl acrylates, vinyl acetates and their methyl-substituted derivatives having 1-8 carbon atoms.

5. The anti-graffiti acrylic emulsion according to claim 3, characterized in that, Component a) is selected from one or more of methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, isoamyl methacrylate, and heptyl methacrylate.

6. The anti-graffiti acrylic emulsion according to claim 3, characterized in that, Component b) is selected from one or more of ethyl acetoacetate, propoxy acetoacetate, butoxy acetoacetate, vinyl acetoacetate, allyl acetoacetate, and their methyl derivatives.

7. The anti-graffiti acrylic emulsion according to claim 6, characterized in that, Component b) is selected from one or both of ethyl acetoacetate and allyl acetoacetate.

8. The anti-graffiti acrylic emulsion according to claim 3, characterized in that, Component c) is selected from unsaturated monomers containing hydrophilic groups, wherein the hydrophilic groups are selected from carboxyl, hydroxyl, amide, sulfonic acid, phosphate, urea, sulfonate, sulfate, and phosphate groups.

9. The anti-graffiti acrylic emulsion according to claim 8, characterized in that, Component c) is selected from one or more of acrylic acid, methacrylic acid, hydroxyethyl acrylate, acrylamide, methacrylamide, vinylalkoxy phosphate, and sodium 2-acrylamide-2-methylpropanesulfonate.

10. The anti-graffiti acrylic emulsion according to claim 3, characterized in that, Component d) is selected from silane coupling agents containing vinyl or epoxy functional groups.

11. The anti-graffiti acrylic emulsion according to claim 10, characterized in that, Component d) is selected from one or more of vinyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and mercaptopropyltrimethoxysilane.

12. The anti-graffiti acrylic emulsion according to any one of claims 3-11, characterized in that, The structural expression of component f) is shown in Equation I:

13. The anti-graffiti acrylic emulsion according to any one of claims 1-11, characterized in that, The raw materials for preparing the emulsion may optionally include emulsifiers, initiators, neutralizers, post-treatment agents, pH adjusters, and water.

14. The anti-graffiti acrylic emulsion according to claim 13, characterized in that, The emulsifier is selected from one or more of sodium dodecyl sulfate, sodium p-styrene sulfonate, sodium dodecylbenzene sulfonate, alcohol ether sulfosuccinate, alkyl alcohol ether sulfate, and alkyl alcohol ether phosphate; The initiator is selected from one or more of sodium persulfate, potassium persulfate, and ammonium persulfate; The neutralizing agent is selected from one or more of sodium bicarbonate, diethylenetriamine, diethanolamine, and ethanolamine; The post-treatment agent includes an oxidizing agent and / or a reducing agent, wherein the oxidizing agent is selected from one or more of tert-butyl hydroperoxide, hydrogen peroxide, sodium persulfate, potassium persulfate, and ammonium persulfate; and the reducing agent is selected from one or more of sodium bisulfite, sodium metabisulfite, and vitamin C. The pH adjuster is selected from one or more of diethylenetriamine, diethanolamine, and ethanolamine.

15. The anti-graffiti acrylic emulsion according to claim 14, characterized in that, The emulsifier is selected from sodium dodecyl sulfate and / or sodium dodecylbenzene sulfonate.

16. The anti-graffiti acrylic emulsion according to claim 14, characterized in that, The amount of the emulsifier used is 1-5% of the total mass of components a)-f).

17. The anti-graffiti acrylic emulsion according to claim 16, characterized in that, The amount of the emulsifier used is 1-2% of the total mass of components a)-f).

18. The anti-graffiti acrylic emulsion according to claim 14, characterized in that, The initiator is selected from sodium persulfate and / or potassium persulfate.

19. The anti-graffiti acrylic emulsion according to claim 14, characterized in that, The total amount of the initiator is 0.2-0.6% of the total mass of components a)-f).

20. The anti-graffiti acrylic emulsion according to claim 19, characterized in that, The total amount of the initiator is 0.2-0.4% of the total mass of components a)-f).

21. The anti-graffiti acrylic emulsion according to claim 14, characterized in that, The neutralizing agent is selected from sodium bicarbonate.

22. The anti-graffiti acrylic emulsion according to claim 14, characterized in that, The amount of neutralizing agent used is 0.1-4% of the total mass of monomer components a)-f).

23. The anti-graffiti acrylic emulsion according to claim 22, characterized in that, The amount of neutralizing agent used is 0.1-0.3% of the total mass of monomer components a)-f).

24. The anti-graffiti acrylic emulsion according to claim 14, characterized in that, The oxidant is selected from tert-butyl hydroperoxide and / or hydrogen peroxide; the reducing agent is selected from sodium bisulfite and / or sodium metabisulfite.

25. The anti-graffiti acrylic emulsion according to claim 14, characterized in that, The total amount of the post-treatment agent is 0.15-0.6% of the total mass of components a)-f).

26. The anti-graffiti acrylic emulsion according to claim 25, characterized in that, The total amount of the post-treatment agent is 0.2-0.4% of the total mass of components a)-f).

27. The anti-graffiti acrylic emulsion according to claim 14, characterized in that, The pH adjuster is selected from diethylenetriamine and / or ethanolamine.

28. The anti-graffiti acrylic emulsion according to claim 14, characterized in that, The endpoint for adding the pH adjuster is to adjust the pH of the system to 7-9.

29. The anti-graffiti acrylic emulsion according to claim 14, characterized in that, The total amount of water used is 1 to 1.5 times the total mass of components a)-f).

30. The anti-graffiti acrylic emulsion according to claim 14, characterized in that, The total amount of water used is 1 to 1.3 times the total mass of components a)-f).

31. A method for preparing an anti-graffiti acrylic emulsion as described in any one of claims 13-30, characterized in that, Includes the following steps: 1) Mix components a), b), c), d), e), f), water, and a portion of the emulsifier evenly to prepare a pre-emulsion; 2) Divide the initiator into two parts and dissolve them in water separately to obtain the dropwise initiator and the bottom initiator; 3) Mix the neutralizer, the remaining emulsifier, and water and add them to the reactor. Stir thoroughly and heat to 80-90℃. Add part of the pre-emulsion and stir until homogeneous. Then add all the initiator from the bottom of the reactor and react for 10-20 minutes to obtain the seed emulsion. 4) Control the temperature inside the reactor to 80-90℃, continue to add the remaining pre-emulsion and all the added initiator to the seed emulsion, add the material over 2-4 hours, and then keep warm for 20-60 minutes. 5) Cool the reactor to 70-80℃, gradually add the post-treatment agent to the reactor, add the agent over 2-4 hours, and then keep it at that temperature for 30-60 minutes; 6) Cool down to below 45℃, add pH adjuster to adjust the pH of the system to 7-9, strip, filter and discharge.

32. The method for preparing the anti-graffiti acrylic emulsion according to claim 31, characterized in that, In step 1), the amount of emulsifier used accounts for 90-99.5% of the total emulsifier mass.

33. The method for preparing the anti-graffiti acrylic emulsion according to claim 32, characterized in that, In step 1), the amount of water used accounts for 25-35% of the total water mass.

34. The method for preparing the anti-graffiti acrylic emulsion according to claim 32, characterized in that, In step 2), the amount of initiator used to prepare the dropwise initiator accounts for 25-50% of its total mass, and the amount of initiator used to prepare the bottom initiator accounts for 50-75% of its total mass.

35. The method for preparing the anti-graffiti acrylic emulsion according to claim 34, characterized in that, In step 3), the amount of pre-emulsion used to prepare the seed emulsion is 1-8% of its total mass.

36. The method for preparing the anti-graffiti acrylic emulsion according to any one of claims 31-35, characterized in that, In step 6), the stripping temperature is 55-85℃ and the pressure is controlled between -75Kpa and -95Kpa.

37. The application of an anti-graffiti acrylic emulsion as described in any one of claims 1-30 or an anti-graffiti acrylic emulsion prepared by the method described in any one of claims 31-36 in coatings.

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