Acrylate emulsion as well as preparation method and application thereof

Abstract

The invention discloses an acrylate emulsion as well as a preparation method and application thereof. The emulsion is prepared from the following raw material components in percentage by mass through emulsion polymerization: a) 15-70 wt% of butyl acrylate, b) 1.3-10 wt% of an olefinic unsaturated monomer containing an acetoacetate functional group, c) 0.5-5 wt% of an unsaturated hydrophilic monomer, d) 0.2-5 wt% of a reactive silane coupling agent, e) 10-50 wt% of styrene and f) 14-25 wt% of an odorless functional monomer. The emulsion disclosed by the invention is mainly applied to building interior wall coatings, the emulsion can keep low VOC after long-term storage and heating while having low VOC, and meanwhile, a paint film is endowed with relatively good scrubbing resistance.

Description

Technical Field

[0001] The present invention relates to an emulsion in the technical field of architectural coatings, and particularly to an acrylate emulsion for architectural interior wall coatings, a preparation method thereof, and an application thereof. Background Art

[0002] Due to its excellent environmental protection and low cost, waterborne acrylic emulsion has gradually become the mainstream of resin for building materials coatings. For architectural interior wall coatings, more attention is paid to indicators such as odor and scrub resistance. Traditional waterborne acrylic emulsions are treated to remove VOCs by stripping. However, the ester groups in acrylic emulsions are prone to hydrolysis. Therefore, after long-term storage, low-VOC emulsions often hydrolyze to produce alcohols with strong odors such as methanol and butanol, resulting in an increase in the VOC of the emulsion and an increase in odor.

[0003] Patent CN 108524991 A discloses a method to achieve a deodorizing effect by post-adding a deodorizing aid. However, the post-added substance also contains unreacted maleic anhydride, which itself can also cause hydrolysis, and it does not solve the problem of the increase in VOC during long-term storage.

[0004] Patent CN 109627369 A introduces a method of improving the wetting and dispersibility of the emulsion, making it easier to disperse natural powders such as shell powder in the emulsion, and reducing harmful substances in the coating. However, this method still does not solve the problem of hydrolysis of ester monomers in the emulsion.

[0005] Therefore, in this field, there is a desire to develop a product with good emulsion hydrolysis resistance and good coating properties. Summary of the Invention

[0006] Aiming at the above problems existing in the prior art, on the premise of the traditional stripping to remove VOC, the present invention introduces a functional monomer that can react with the hydrolysis products of the emulsion, so that the alcohols produced by hydrolysis are greatly reduced, thereby reducing the odor of the emulsion.

[0007] The present invention has experimentally found that by utilizing the strong transesterification characteristic of the ester group of monomer Q, the functional monomer Q undergoes transesterification and reacts with the alcohol R-OH produced by hydrolysis. First, maleic anhydride reacts with A to form a deodorizing functional monomer, and then the functional monomer is introduced into the polymer. The transesterification reaction of the functional monomer with alcohol under alkaline conditions can generate the corresponding N-formylmaleimide and the corresponding B ester, thereby reducing the alcohol VOC substances produced by hydrolysis in the emulsion. The specific principle is as follows.

[0008]

[0009] To achieve the above object, the technical solutions adopted by the present invention are as follows:

[0010] The present invention provides an acrylate emulsion, which is prepared by emulsion polymerization from raw material components including the following mass percentages:

[0011] a) 15 - 70% of butyl acrylate, such as 20%, 30%, 40%, 50%, 60%, 70%, preferably 40 - 60%;

[0012] b) 1.3 - 10% of an ethylenically unsaturated monomer containing an acetoacetate functional group, such as 2%, 5%, 8%, 10%, preferably 2 - 4%;

[0013] c) 0.5 - 5% of an unsaturated hydrophilic monomer, such as 1%, 2%, 3%, 4%, 5%, preferably 2 - 5%;

[0014] d) 0.2 - 5% of a reactive silane coupling agent, such as 0.5%, 1%, 3%, 5%, preferably 0.5 - 2%;

[0015] e) 10 - 50% of styrene, such as 10%, 20%, 30% or 40%, preferably 10 - 30%;

[0016] f) 14 - 25% of a smell - reducing functional monomer, such as 15%, 20%, preferably 10 - 15%;

[0017] Among them, the total of a), b), c), d), e), and f) is 100% based on the total weight.

[0018] The smell - reducing functional monomer is

[0019] In addition, in the present invention, unless otherwise specified, the percentage contents involved are all mass percentage contents.

[0020] In the present invention, the ethylenically unsaturated monomer containing an acetoacetate functional group in component b) is selected from one or more of ethyl acetoacetoxy (meth)acrylate, propoxy acetoacetoxy (meth)acrylate, butoxy acetoacetoxy (meth)acrylate, vinyl acetoacetate, allyl acetoacetate, preferably one or more of ethyl acetoacetoxy (meth)acrylate and allyl acetoacetate.

[0021] In the present invention, the unsaturated hydrophilic monomer in component c) is selected from one or more of unsaturated monomers having hydrophilic groups such as carboxyl, hydroxyl, amide, sulfonic acid, phosphate ester, urea, sulfonate, sulfate or phosphate groups, preferably one or more of acrylic acid, methacrylic acid, 2 - hydroxyethyl acrylate, acrylamide, N - (2 - hydroxyethyl) methacrylamide, vinyl alkoxy phosphate, sodium 2 - acrylamido - 2 - methylpropanesulfonate.

[0022] In the present invention, the component d) reactive silane coupling agent is selected from one or more of vinyl silane coupling agents and epoxy silane coupling agents, preferably one or more of vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-glycidoxypropyltrimethoxysilane.

[0023] In a preferred embodiment, the acrylate emulsion of the present invention utilizes the strong transesterification characteristic of monomer Q. The functional monomer Q undergoes a transesterification reaction with the alcohol generated by the hydrolysis of the acrylate. The transesterification reaction of the functional monomer with the alcohol under alkaline conditions generates the corresponding N-formyl maleimide and the corresponding B ester, thereby reducing the alcohol VOC substances generated due to hydrolysis in the emulsion, that is, reducing the VOC in the emulsion, improving the hydrophobicity of the emulsion, and enhancing its scrub resistance.

[0024] The acrylate emulsion of the present invention is obtained by an emulsion polymerization method, which is a polymerization method known in the prior art, and those skilled in the art can adopt any achievable method to prepare it.

[0025] Preferably, the raw materials for preparing the acrylate emulsion of the present invention also optionally include an emulsifier, an initiator, a neutralizing agent, a post-treatment agent, an alcohol solvent, water, etc.

[0026] In the present invention, the emulsifier is selected from one or more of sodium dodecyl sulfate, sodium styrene sulfonate, sodium dodecyl benzene sulfonate, alcohol ether sulfosuccinate, alkyl alcohol ether sulfate, and alkyl alcohol ether phosphate, preferably sodium dodecyl sulfate and / or sodium dodecyl benzene sulfonate;

[0027] Preferably, the total amount of the emulsifier used is 1-5% of the total mass of components a)-f), such as 1%, 2%, 3%, 4%, 5%, preferably 1-2%.

[0028] In the present invention, the initiator is selected from one or more of sodium persulfate, potassium persulfate, and ammonium persulfate, preferably sodium persulfate and / or potassium persulfate.

[0029] Preferably, the total amount of the initiator used is 0.2-0.6% of the total mass of components a)-f), such as 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, preferably 0.2-0.4%.

[0030] In the present invention, the neutralizing agent is selected from one or more of sodium bicarbonate, diethylenetriamine, diethanolamine, and ethanolamine, preferably sodium bicarbonate; preferably, the amount of the neutralizing agent used is 0.1-4% of the total mass of monomer components a)-f), such as 0.1%, 0.2%, 0.3%, 0.5%, 1.0%, 2.0%, 3.0%, preferably 0.1-0.3%.

[0031] In the present invention, 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 hydroperoxide, hydrogen peroxide, sodium persulfate, potassium persulfate, and ammonium persulfate, preferably tert-butyl hydroperoxide and / or hydrogen peroxide; the reducing agent is selected from one or more of sodium bisulfite, sodium metabisulfite, and vitamin C, preferably sodium bisulfite and / or sodium metabisulfite;

[0032] Preferably, the total amount of the post-treatment agent is 0.15-0.6% of the total mass of components a)-f), such as 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, preferably 0.2-0.4%.

[0033] In the present invention, the pH regulator is selected from one or more of sodium bicarbonate, diethylenetriamine, diethanolamine, and ethanolamine, preferably diethylenetriamine and / or ethanolamine;

[0034] Preferably, the end point of the addition amount of the pH regulator is to adjust the pH to 7-9.

[0035] In the present invention, the alcohol solvent is selected from one or more of ethanol, n-butanol, and isobutanol, preferably ethanol; preferably, the total amount of the alcohol solvent is 0.01-0.5% of the total mass of monomer components a)-f), such as 0.01%, 0.015%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, preferably 0.01-0.3%.

[0036] In the present invention, the total amount of water is 1-1.5 times the total mass of components a)-f), such as 1.1 times, 1.2 times, 1.3 times, 1.4 times, preferably 1-1.3 times.

[0037] The present invention also provides a method for preparing the above acrylate emulsion, comprising the following steps:

[0038] 1) Mix components a), b), c), d), e), f), part of water, the alcohol solvent, and part of the emulsifier to prepare a pre-emulsion;

[0039] 2) Dissolve part of the initiator in part of the water to obtain a dropping initiator; dissolve the remaining initiator in part of the water to obtain a bottom initiator in the kettle;

[0040] 3) Mix the remaining emulsifier with the remaining water and the neutralizing agent, add them to the reaction kettle, stir well and then heat up to 80-90°C; add part of the pre-emulsion, and after stirring evenly, add all the bottom initiator in the kettle, and react for 10-20 min to obtain a seed emulsion;

[0041] 4) Control the temperature in the reaction kettle at 80 - 90 °C, and continue to add the remaining pre-emulsified liquid and all of the dropping initiator to the seed emulsion. The feeding time is 2 - 4 h, and then keep it warm for 20 - 60 min, such as 20, 40 or 60 min;

[0042] 5) Cool down the reaction kettle to 70 - 80 °C, and gradually add the post-treatment agent to the reaction kettle within 20 - 60 min, such as 30, 40 or 50 min. The feeding time is 2 - 4 h, and then keep it warm for 30 - 60 min, such as 40 or 50 min;

[0043] 6) Cool down to below 45 °C, add a pH regulator to adjust the pH of the system to 7 - 9, and then carry out steam stripping and filtration for discharging at 55 - 80 °C.

[0044] In step 1) of the preparation method of the present invention, the addition amount of the emulsifier is 90 - 99.5% of the total mass of the emulsifier, such as 95%, 98%;

[0045] The addition amount of the water is 25 - 35% of the total mass of the water, such as 25%, 30% or 35%.

[0046] In step 2) of the preparation method of the present invention, 25 - 50% of the total mass of the initiator, such as 35%, 40%, 45%, is mixed and dissolved with 1 - 6% of the total mass of the water, such as 2%, 4%, 6%, to obtain the dropping initiator; then the remaining initiator is mixed and dissolved with 1 - 6% of the total mass of the water, such as 2%, 4%, 6%, to obtain the bottom initiator in the kettle. In the above preparation process, the addition of the initiator is well-known in the art, and it is added in two steps to prepare the dropping initiator and the bottom initiator respectively. For example, the ratio of the two addition amounts can be 1:2 - 2:1, such as 1.5:1; this feeding form belongs to the commonly used feeding form in the art and will not be elaborated here.

[0047] In step 3) of the preparation method of the present invention, the mass of the pre-emulsified liquid used for preparing the seed emulsion is 1 - 8% of the total mass of the pre-emulsified liquid, such as 2%, 4%, 5%, 6%.

[0048] The present invention also provides an application of the acrylate emulsion described above in the preparation of coatings.

[0049] The acrylate emulsion of the present invention has the advantages of low VOC content and good environmental protection performance, and is especially suitable for the field of interior wall coatings for buildings.

[0050] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows:

[0051] 1. By using the principle of transesterification, the corresponding alcohols generated by hydrolysis in the emulsion are reacted into high-boiling alcohols and esters, greatly reducing the VOC in the coatings.

[0052] 2. Due to the introduction of hydrophobic functional groups, the hydrophobicity of the emulsion is enhanced, and hydrophobicity is an important factor affecting scrub resistance. Therefore, the scrub resistance of the coating is also further improved.

[0053] 3. The synthesis process is simple, the operation is convenient, the cost is low, the VOC content is low, and the safety is high. Brief Description of the Drawings

[0054] Figure 1 It is the NMR spectrum of functional monomer Q Detailed Embodiments

[0055] The present invention will be further described below through specific embodiments. The embodiments described in the present invention are only for the purpose of illustrating the present invention and do not limit the scope of the present invention.

[0056] The raw materials used in the following examples are shown in Table 1. Other raw materials not specifically stated are ordinary commercially available raw materials:

[0057] Table 1

[0058]

[0059] The following treatment processes are adopted in each of the following examples:

[0060] Stripping: The emulsion is put into a buffer kettle and preheated to 55 °C, and then fed into a stripping tower for stripping (stripping temperature 55 °C); the emulsion is fed at the top of the tower, and air and steam are fed at the bottom of the tower. The two are in countercurrent contact and are mixed at high speed in a short time. The steam and air entrain the VOC components and are separated from the emulsion through the vacuum tail gas pipeline. The emulsion is discharged from the bottom. During the stripping process, the relative flow rates of air, steam and emulsion are 1:0.5:10.

[0061] Assessment of odor (olfactory grade): The odor is evaluated according to the olfactory perception. 10 people are selected to evaluate the odor in the polymer latex tank. The evaluation results are divided into five grades from 1 to 5, as shown in Table 2:

[0062] Table 2

[0063] Level Unpleasant odor 5 None 4 Slight 3 Moderate 2 Strong 1 Severe

[0064] Low-temperature coalescence evaluation (LTC): Scrape putty on a high-density non-asbestos fiberboard of A4 size. The substrate conforms to NAF (non-asbestos) in JC / T412.1-2006. After drying, it is polished flat with sandpaper. After scraping a film with a 400um film applicator on the putty board of A4 size, it is immediately placed in a low-temperature box at 3 °C. After 4 hours, observe the cracking situation on the surface of the coating film for comparison. The degree of cracking is rated from level 1 to 5, as shown in Table 3:

[0065] Table 3

[0066]

[0067]

[0068] Evaluation of paint film scrub resistance: Test the paint film scrub resistance according to GB / T 9266-2009;

[0069] Freeze-thaw stability assessment: Determine the freeze-thaw stability of latex paint according to GB / T 9268-2008;

[0070] Formaldehyde purification efficiency evaluation: Test the formaldehyde purification efficiency of the paint film according to JC / T 1074-2008.

[0071] Functional monomer preparation example

[0072] Prepare the foaming monomer as follows:

[0073] Maleic anhydride and substance A were mixed at a molar ratio of 1:1.2, methanol / maleic anhydride = 10:1 was added as a solvent, the reaction temperature was adjusted to 25 degrees Celsius, and the reaction was stirred for 24 hours.

[0074] After the reaction is completed, the temperature is lowered to 0 degrees Celsius, and the product can be cooled and precipitated, and the product can be obtained by filtration. The NMR image is as follows: 1 H NMR (300MHz, DMSO): δ3.81(s,3H),5.00(s,2H),6.88(d,2H),7.02(d,2H).7.86(d,2H)

[0075] [Example 1]

[0076] Preparation of acrylic emulsion:

[0077] 1) At room temperature and pressure, 9.8 g of emulsifier SDS, 10 g of emulsifier SSS, and 480 g of deionized water are added to an emulsifier tank, stirred and dissolved, and 180 g of styrene (component e), 180 g of functional monomer Q (component f), 180 g of benzylamine (component h), 660 g of BA (component a), 40 g of AAEM (component b), 15 g of AA (component c), 5 g of A171 (component d), 100 g of LMA (component g), and 2 g of ethanol are added in sequence and mixed to prepare a pre-emulsion.

[0078] 2) 1.6 g of initiator APS was fully mixed with 40 g of water to obtain a dropwise initiator solution; the remaining 2.4 g of initiator APS was fully mixed with 24 g of water to obtain a bottom initiator.

[0079] 3) Add the remaining 0.2 g of emulsifier SDS, 900 g of water, and 2 g of sodium bicarbonate to the bottom of the reaction kettle, stir well to dissolve, heat up to 85 °C, add 50 g of pre-emulsion, and after stirring evenly, add all the bottom initiator and react for 10 min to obtain the seed emulsion.

[0080] 4) Keep the temperature of the seed emulsion at 85 °C, and at the same time, dropwise add the remaining pre-emulsion and all the dropwise initiator. The dropping time of the initiator is 4 h, and then keep warm for 20 min.

[0081] 5) After the heat preservation is completed, cool down to 75 °C, and at the same time start to dropwise add 2.5 g of t-BHP and 40 g of 5% aqueous solution of sodium bisulfate. The dropping time is 2 h, and after completion, keep warm for about 30 min.

[0082] 6) Cool down to below 45 °C, add 180 g of pH regulator diethylenetriamine to adjust the pH to about 8, then cool down to 55 °C for stripping. After the stripping is completed and the temperature drops below 45 °C, filter through a 100-mesh filter and discharge to obtain the acrylate emulsion.

[0083] Prepare latex paints (coatings) respectively according to the formulations in Table 4 with the prepared emulsion, and conduct tests on the properties of latex paints or paint films such as scrub resistance, LTC, freeze-thaw resistance, etc.

[0084] Table 4

[0085]

[0086]

[0087] During the experimental time of the interior wall detection items specified in GB / T 9756-2009, it is better than this national standard. See Table 5 for details.

[0088]

Example 2 - 8

[0089] Prepare acrylic emulsions respectively according to the method basically the same as that in Example 1, with the only difference being that the raw material selection and dosage in Table 2 are different.

[0090] Table 5 Raw material selection and dosage in Examples 1 - 8 (unit: g)

[0091]

[0092]

[0093] Prepare latex paints with the prepared emulsion according to the formulation in Table 1, and conduct tests on the properties of latex paints or paint films such as scrub resistance, LTC, freeze-thaw resistance, VOC property, etc. The results are shown in Table 6.

[0094] Table 6

[0095]

[0096]

[0097]

Comparative Example 1

[0098] Prepare emulsion O according to the method and raw material dosage in Example 1, with the only difference being that: replace component f) functional monomer Q with maleic anhydride.

[0099] Prepare latex paint with the prepared emulsion according to the formula in Table 1, and conduct tests on latex paint or film properties such as scrub resistance, LTC, freeze-thaw resistance, etc. The results are shown in Table 5.

[0100]

Comparative Example 2

[0101] Prepare emulsion 1 according to the method and raw material dosage in Example 1, with the only difference being that: replace functional monomer Q with small molecule substance A.

[0102] Prepare latex paint with the prepared emulsion according to the formula in Table 1, and conduct tests on latex paint or film properties such as scrub resistance, LTC, freeze-thaw resistance, etc. The results are shown in Table 5.

[0103]

Comparative Example 3

[0104] Prepare emulsion 2 according to the method and raw material dosage in Example 1, with the only difference being that: replace the neutralizer with vinyl dianhydride.

[0105] Prepare latex paint with the prepared emulsion according to the formula in Table 1, and conduct tests on latex paint or film properties such as scrub resistance, LTC, freeze-thaw resistance, etc. The results are shown in Table 5.

[0106]

Comparative Example 4

[0107] Prepare emulsion 3 according to the method and raw material dosage in Example 1, with the only difference being that: do not add component a) butyl acrylate BA, the final solid content of the emulsion is 45%, the pH is 8, the emulsion particle size is 130 nm, and the MFFT is 63 °C.

[0108] Prepare latex paint with the prepared emulsion according to the formula in Table 1, and conduct tests on latex paint or film properties such as scrub resistance, LTC, freeze-thaw resistance, etc. The results are shown in Table 6.

[0109] Prepare latex paint with the prepared emulsion according to the formula in Table 1, and conduct tests on latex paint or film properties such as scrub resistance, LTC, freeze-thaw resistance, etc. The results are shown in Table 6.

[0110] As shown in Table 5, latex paints were prepared from the emulsions obtained in Examples 1-5, and the performance test results all met the requirements for interior wall coatings for children's rooms in "GB / T 34676-2017 Interior Wall Coatings for Children's Room Decoration", and the film-forming property and freeze-thaw stability were significantly improved.

[0111] It can be seen from the above test results that

[0112] In the formula of the present invention, the functional monomer reduces the VOC level in the emulsion through transesterification and improves the odor pleasantness of the emulsion.

[0113] It can be seen from the test results of the examples and comparative examples that by introducing ester groups, the scrubbing level and freeze resistance of the emulsion have been significantly improved. After reducing the functional monomers necessary for film formation, the film-forming property and scrub resistance of the coating have been affected.

[0114] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the method of the present invention, several improvements and supplements can still be made, and these improvements and supplements should also be regarded as the protection scope of the present invention.

Claims

1. An acrylate emulsion is prepared by emulsion polymerization from raw material components including the following mass percentages: a) 15 - 70% butyl acrylate, preferably 40 - 60%; b) 1.3 - 10% ethylenically unsaturated monomer containing an acetoacetate functional group, preferably 2 - 4%; c) 0.5 - 5% unsaturated hydrophilic monomer, preferably 2 - 5%; d) 0.2 - 5% reactive silane coupling agent, preferably 0.5 - 2%; e) 10 - 50% styrene, preferably 10 - 30%; f) 14 - 25% odorless functional monomer, preferably 10 - 15%; wherein, the total of a), b), c), d), e), and f) is 100% by total mass; The odor-removing functional monomer is 2. The acrylate emulsion according to claim 1, characterized in that the ethylenically unsaturated monomer containing an acetoacetate functional group in component b) is selected from one or more of ethyl acetoacetoxy (meth)acrylate, propoxy acetoacetoxy (meth)acrylate, butoxy acetoacetoxy (meth)acrylate, vinyl acetoacetate, allyl acetoacetate, preferably one or more of ethyl acetoacetoxy (meth)acrylate and allyl acetoacetate.

3. The acrylate emulsion according to claim 1 or 2, characterized in that the unsaturated hydrophilic monomer in component c) is selected from one or more of unsaturated monomers having hydrophilic groups such as carboxyl, hydroxyl, amide, sulfonic acid, phosphate ester, urea, sulfonate, sulfate, or phosphate groups, preferably one or more of acrylic acid, methacrylic acid, hydroxyethyl acrylate, acrylamide, N - (2 - hydroxyethyl)methacrylamide, vinyl alkoxy phosphate, and sodium 2 - acrylamido - 2 - methylpropane sulfonate.

4. The acrylate emulsion according to any one of claims 1 - 3, characterized in that the reactive silane coupling agent in component d) is selected from one or more of vinyl silane coupling agents and epoxy silane coupling agents, preferably one or more of vinyltrimethoxysilane, γ - methacryloxypropyltrimethoxysilane, and γ - glycidoxypropyltrimethoxysilane.

5. The acrylate emulsion according to any one of claims 1 - 4, characterized in that the raw materials for preparing the acrylate emulsion optionally further include one or more of an emulsifier, an initiator, a neutralizing agent, a post - treatment agent, an alcohol solvent, and water.

6. The method for preparing the acrylate emulsion according to any one of claims 1 - 5, comprising the following steps: 1) Mix component a), component b), component c), component d), component e), component f), part of water, an alcohol solvent, and part of the emulsifier to prepare a pre - emulsion; 2) Dissolve part of the initiator in part of the water to obtain a dropping initiator; dissolve the remaining initiator in part of the water to obtain a bottom - of - the - kettle initiator; 3) Mix the remaining emulsifier with the remaining water and the neutralizing agent, add them to the reaction kettle, stir well and heat up to 80 - 90°C; add part of the pre - emulsion, and after stirring evenly, add all of the bottom - of - the - kettle initiator and react for 10 - 20 min to obtain a seed emulsion; 4) Control the temperature in the reaction kettle at 80 - 90 °C, and continue to add the remaining pre-emulsion and all of the dropping initiator to the seed emulsion. The feeding time is 2 - 4 h, and then keep it warm for 20 - 60 min, such as 20, 40 or 60 min; 5) Cool the reaction kettle to 70 - 80 °C, and gradually add the post-treatment agent to the reaction kettle within 20 - 60 min, such as 30, 40 or 50 min. The feeding time is 2 - 4 h, and then keep it warm for 30 - 60 min, such as 40 or 50 min; 6) Cool it down to below 45 °C, add a pH regulator to adjust the pH of the system to 7 - 9, and carry out steam stripping and filtration for discharging at 55 - 80 °C.

7. The method according to claim 6, characterized in that: In step 1), the addition amount of the emulsifier is 90 - 99.5% of the total mass of the emulsifier; the addition amount of the water is 25 - 35% of the total mass of the water.

8. The method according to claim 6 or 7, characterized in that: In step 3), the mass of the pre-emulsion used for preparing the seed emulsion is 1 - 8% of the total mass of the pre-emulsion.

9. Use of the acrylate emulsion according to any one of claims 1 - 5 or the acrylate emulsion prepared by the preparation method according to any one of claims 6 - 8 in the preparation of coatings.

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