Acrylic emulsion for interior walls and preparation method therefor

Abstract

The present invention provides an acrylic emulsion for interior walls. The raw materials of the acrylic emulsion for interior walls comprise an emulsifier, water, an initiator and monomers. The monomers comprise a soft monomer, a hard monomer, a functional monomer and an organosilicon monomer; in addition, the average particle size of the particles of the acrylic emulsion for interior walls is ≤120 nm. The present invention also provides a preparation method for the acrylic emulsion for interior walls. The acrylic emulsion for interior walls of the present invention is prepared by means of a combination of monomer formulas, matching a relatively large amount of anionic and nonionic emulsifiers; by means of controlling the amount of a seed emulsion added and using a silicon addition process for polymerization, the obtained emulsion not only has excellent environmental performance and low odor, but also has excellent mechanical properties and good compatibility with substrates, causing an emulsion paint have excellent scrub resistance and water whitening resistance.

Description

Acrylic emulsion for interior walls and preparation method thereof Technical Field

[0001] The invention relates to the technical field of coatings, in particular to an acrylic emulsion for interior walls and a preparation method thereof. Background Art

[0002] With the continuous advancement of science and technology, people's requirements for the beautification of the interior and exterior walls of buildings and the increasing awareness of environmental protection have led to the rapid development of building decoration materials and new requirements for building interior and exterior wall coatings.

[0003] Interior wall paints are used for interior wall decoration. They contain formaldehyde, acetaldehyde, benzene, vinyl acetate, naphthalene, and other substances. After application, some of these organic compounds evaporate into the air. These components, mostly from unreacted residual monomers in the emulsion and a small amount of film-forming aids in the paint, can increase VOC levels in indoor air and worsen odors. This can further contribute to indoor air pollution, affecting the health of construction workers and residents.

[0004] Water-based acrylic emulsions are important raw materials for interior wall paints, and their quality directly determines the quality of the paint. Prior art discloses some low-odor acrylic emulsions that can produce low-odor coatings with small particle size and moderate viscosity. However, these emulsions suffer from poor scrub resistance and water-whitening resistance, lack gloss after application, and are prone to shedding after prolonged use, making them unsuitable for demanding applications.

[0005] Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide an acrylic emulsion for interior walls and a preparation method thereof, wherein the obtained acrylic emulsion for interior walls has the characteristics of fine particle size and low odor, and has strong scrub resistance and water whitening resistance.

[0007] Based on the above purpose, the present invention provides an acrylic emulsion for interior walls, wherein the raw materials of the acrylic emulsion for interior walls include an emulsifier, water, an initiator and a monomer;

[0008] The monomers include soft monomers, hard monomers, functional monomers and silicone monomers; and,

[0009] The average particle size of the particles of the acrylic emulsion for interior walls is ≤120nm;

[0010] in,

[0011] The soft monomer is an acrylic soft monomer with a Tg range of -70°C to -20°C;

[0012] The hard monomer is styrene;

[0013] The functional monomer includes one or a combination of acrylic acid, methacrylic acid, acrylamide and methacrylamide.

[0014] In the technical solution of the present invention, the average particle size of the particles of the acrylic emulsion for interior walls is distributed within 120 nm, and the smaller the better. Small-particle emulsions are latex particles with denser polymerization, which greatly improves stability. Moreover, when small-particle emulsions are applied to interior wall paint, they are more conducive to film formation and adhesion, thereby improving the product's scrub resistance and water whitening resistance. Emulsifiers are one of the key factors affecting the latex particles of emulsion polymers. The site of emulsion polymerization is micelles. Emulsifiers and monomers mix to form micelles. When there is more emulsifier, more micelles are formed, increasing the polymerization site and reducing the polymer particle size. When there is less emulsifier, fewer micelles are formed and the polymer particle size increases. However, too little emulsifier is not conducive to the progress of emulsion polymerization and affects the performance of the emulsion.

[0015] Therefore, the technical solution of the present invention controls the components and the preparation process to obtain an average particle size of the particles ≤120 nm; preferably ≤100 nm; more preferably ≤90 nm; for example, 70-90 nm.

[0016] In the above-mentioned acrylic emulsion for interior walls, preferably, the functional monomer is acrylic acid and / or acrylamide. Further preferably, the functional monomer is acrylic acid.

[0017] In the above-mentioned acrylic emulsion for interior walls, preferably, the soft monomer is butyl acrylate and / or isooctyl acrylate. In the above-mentioned acrylic emulsion for interior walls, the soft monomer is an acrylic ester soft monomer polymer, which gives the emulsion good elasticity, softness and ductility after film formation.

[0018] In the above-mentioned acrylic emulsion for interior walls, preferably, the organic silicon monomer is selected from one or a combination of vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane and γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0019] In the above-mentioned acrylic emulsion for interior walls, it is further preferred that the organic silicon monomer can be selected from A171 silane coupling agent, A174 silane coupling agent, A187 silane coupling agent, etc. produced by Momentive.

[0020] In the above-mentioned acrylic emulsion for interior walls, preferably, the emulsifier includes an anionic emulsifier and a nonionic emulsifier;

[0021] The anionic emulsifier includes one or a combination of fatty alcohol polyoxyethylene ether succinate, sodium dodecyl diphenyl ether disulfonate and sodium allyloxy hydroxypropyl sulfonate.

[0022] In the above-mentioned acrylic emulsion for interior walls, preferably, the nonionic emulsifier includes one or more combinations of fatty alcohol polyoxyethylene ether emulsifiers, fatty acid polyoxyethylene ester emulsifiers and polyoxyethylene alkylamine emulsifiers.

[0023] In the above-mentioned acrylic emulsion for interior walls, the amount of raw materials can be adjusted as needed, but the excellent technical effects of the present invention cannot be achieved. Therefore, preferably, the raw materials of the acrylic emulsion for interior walls include 1-15 parts of emulsifier, 0.1-5 parts of initiator, 25-40 parts of soft monomer, 30-50 parts of hard monomer, 1-3 parts of functional monomer and 2-3 parts of silicone monomer, and the amount of water is 85wt%-115wt% of the total weight of the monomers.

[0024] In the above-mentioned acrylic emulsion for interior walls, preferably, the initiator includes one or a combination of ammonium persulfate, sodium persulfate and potassium persulfate.

[0025] In the above-mentioned acrylic emulsion for interior walls, preferably, the fatty alcohol polyoxyethylene ether succinate is a sulfonate obtained by sulfonating fatty alcohol with polyoxyethylene (EO). Further preferably, the fatty alcohol polyoxyethylene ether succinate can be AEROSOL A-102 emulsion emulsifier from Cytec.

[0026] In the above-mentioned acrylic emulsion for interior walls, preferably, the sodium dodecyl diphenyl ether disulfonate can be DOWFAX 2A1 emulsifier from Dow Chemical;

[0027] In the above-mentioned acrylic emulsion for interior walls, preferably, the nonionic emulsifier is a fatty alcohol polyoxyethylene ether emulsifier. Further preferably, the nonionic emulsifier can be isomeric tridecanol polyoxyethylene ether TO-8 or isomeric tridecanol polyoxyethylene ether TO-10 produced by BASF.

[0028] In the above-mentioned acrylic emulsion for interior walls of the present invention, in order to prepare an excellent acrylic emulsion for interior walls, preferably, the raw materials of the acrylic emulsion for interior walls further include an oxidizing agent and a reducing agent;

[0029] The oxidant is tert-butyl hydroperoxide or hydrogen peroxide, and the amount of the oxidant added is 0.1 wt% to 1 wt% of the total weight of the monomers, and more preferably 0.5 wt% to 0.8 wt%.

[0030] In the above-mentioned acrylic emulsion for interior walls, preferably, the reducing agent is sodium salt of vitamin C (VCNa) and / or vitamin C; the added amount of the reducing agent is 0.1wt%-1wt% of the total weight of the monomers; more preferably 0.5wt%-0.8wt%.

[0031] In the above-mentioned acrylic emulsion for interior walls, preferably, the raw materials of the acrylic emulsion for interior walls further include a post-initiator;

[0032] The post-initiator includes one or a combination of ammonium persulfate, sodium persulfate, and potassium persulfate; the amount of the post-initiator used is 0.05 wt% to 1 wt% of the total weight of the monomers. More preferably, the amount of the post-initiator used is 0.3 wt% to 0.5 wt% of the total weight of the monomers.

[0033] In the above-mentioned acrylic emulsion for interior walls, preferably, the initiator and the post-initiator are added in the form of an aqueous solution for the best effect.

[0034] The present invention also provides a method for preparing the above-mentioned acrylic emulsion for interior walls, comprising the following steps:

[0035] Mixing the first portion of water, the first portion of emulsifier, the monomer and the first portion of initiator to react to obtain a pre-emulsion;

[0036] Mix the second part of water and the second part of emulsifier, heat them up, add the second part of initiator, and react to obtain a kettle bottom liquid;

[0037] The pre-emulsion accounting for 6%-10% of the total weight of the pre-emulsion is added as seed emulsion to the bottom liquid of the kettle. After the reaction temperature is raised, the remaining pre-emulsion is added dropwise at a uniform speed until the addition is completed. After post-treatment, the pH value is adjusted to 7-8 to obtain an acrylic emulsion for interior walls.

[0038] In the above preparation method, the first part of water and the second part of water constitute the complete amount of water; the first part of emulsifier and the second part of emulsifier constitute the complete amount of emulsifier; the first part of initiator and the second part of initiator constitute the complete amount of initiator.

[0039] In the above preparation method, preferably, the step of adjusting the pH value to 7-8 after post-treatment is to cool the material after post-treatment to below 45°C, filter the material through a 200-mesh filter cloth, and add ammonia water to adjust the pH value to 7-8.

[0040] In the above preparation method, preferably, in the step of adding 6%-10% of the total weight of the pre-emulsion into the bottom liquid of the kettle as the seed emulsion, in order to obtain better results, 8%-10% of the total weight of the pre-emulsion can be controlled to be added into the bottom liquid of the kettle as the seed emulsion.

[0041] In the above preparation method, preferably, the heating refers to raising the temperature to 85-90°C; in the above preparation method, further preferably, the heating refers to raising the temperature to 86-88°C.

[0042] In the above preparation method, preferably, the post-treatment is to continue to dropwise add the post-initiator after the pre-emulsion is added, keep warm for 25-90 minutes, and then dropwise add the oxidizing agent and the reducing agent simultaneously.

[0043] In the above preparation method, preferably, in the step of uniformly adding the remaining pre-emulsion until the addition is completed, the time of the addition is controlled to be 3-6 hours; more preferably, the time of the addition is controlled to be 4-6 hours.

[0044] In the above preparation method, preferably, the amount of the first portion of water is 50%-70% of the total weight of the monomers; the first portion of emulsifiers includes anionic emulsifiers and nonionic emulsifiers, the amount of the anionic emulsifier is 2%-5% of the total weight of the monomers, and the amount of the nonionic emulsifier is 1.5-2% of the total weight of the monomers; the amount of the first portion of initiator is 0.05%-0.15% of the total weight of the monomers. Further preferably, the first portion of emulsifiers includes anionic emulsifiers and nonionic emulsifiers, and the amount of the anionic emulsifier is 2.5%-3.5% of the total weight of the monomers.

[0045] In the above preparation method, preferably, the amount of the second part of water is 35%-45% of the total weight of the monomers; the second part of the emulsifier includes an anionic emulsifier and a nonionic emulsifier, the amount of the anionic emulsifier is 2%-3.5% of the total weight of the monomers, and the amount of the nonionic emulsifier is 2%-3% of the total weight of the monomers; the amount of the second part of the initiator is 0.5%-1% of the total weight of the monomers.

[0046] In the above-mentioned acrylic emulsion for interior walls and its preparation method, residual monomers are further eliminated by post-adding a post-initiator; the oxidant and the reducing agent react with the organic matter in the emulsion to produce an oxidation-reduction reaction, decomposing the organic matter into smaller molecules, reducing the volatility and organic residue of the emulsion, eliminating residual monomers, helping to eliminate or reduce the odor in the emulsion, reducing the content of organic matter, and improving the long-term stability of the emulsion.

[0047] From the above description, it can be seen that the technical solution provided by the present invention has the following significant beneficial effects:

[0048] The acrylic emulsion for interior walls of the present invention is prepared by combining monomer formulas, adding a relatively large amount of anionic and nonionic emulsifiers, controlling the amount of seed emulsion added, and adopting a silicon addition process for polymerization. The obtained emulsion not only has excellent environmental performance and low odor, but also has excellent mechanical properties and good compatibility with substrates, so that the emulsion paint has excellent scrub resistance and water whitening resistance. DETAILED DESCRIPTION

[0049] To provide a clearer understanding of the technical features, objectives, and beneficial effects of the present invention, the following detailed description of the technical solution of the present invention is provided. However, this description should not be construed as limiting the scope of the present invention. The experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0050] In the prior art, the development of acrylic emulsions for interior wall applications is generally plagued by issues such as odor, scrub resistance, and poor water-whitening resistance, particularly for styrene-acrylic emulsions. After extensive and in-depth research, the inventors discovered that the source of emulsion odor is partly residual monomer, such as styrene, and partly the added emulsifier. Styrene monomer is rarely completely consumed during the polymerization process, and styrene itself contains odorous hydrocarbon impurities, resulting in a strong odor. The emulsifier itself also contains odorous impurities. Furthermore, the scrub resistance and water-whitening resistance of styrene-acrylic emulsions are less than ideal. Therefore, the present invention provides an acrylic emulsion for interior wall applications, as shown in the following examples.

[0051] Example

[0052] This embodiment provides an acrylic emulsion for interior walls. The raw materials of the acrylic emulsion for interior walls include, by parts by weight, an emulsifier, an initiator, a soft monomer, a hard monomer, a functional monomer, a silicone monomer, and water.

[0053] The specific raw materials and their amounts used in this embodiment are shown in Table 1. The anionic emulsifier used in the emulsifier is fatty alcohol polyoxyethylene ether succinate, which is AEROSOL A-102 emulsion emulsifier produced by Cytec; the nonionic emulsifier is isomeric tridecanol polyoxyethylene ether TO-8 produced by BASF.

[0054] The functional monomer is acrylic acid; the soft monomers are butyl acrylate and isooctyl acrylate; the hard monomer is styrene; and the silicone monomer is A171 silane coupling agent produced by Momentive (a vinyl trimethoxysilane that can be replaced with γ-methacryloyloxypropyltrimethoxysilane or γ-(2,3-epoxypropyl)propyltrimethoxysilane as needed). The initiator is sodium persulfate.

[0055] The raw materials of this embodiment may also include an oxidizing agent, a reducing agent, and a post-initiator used in post-treatment. The post-initiator used in post-treatment is sodium persulfate, the oxidizing agent is hydrogen peroxide, and the reducing agent is vitamin C.

[0056] The acrylic emulsion for interior walls of this embodiment is prepared by the following method, and the parameters and amounts are shown in Table 1:

[0057] Preparing a pre-emulsion: In a monomer tank, deionized water, the first portion of the emulsifier (comprising a portion of the anionic emulsifier AEROSOL A-102 and a portion of the nonionic emulsifier TO-8; the anionic emulsifier in this embodiment can be replaced with DOWFAX 2A1 emulsifier or sodium allyloxyhydroxypropyl sulfonate from Dow Chemical as needed; the nonionic emulsifier can be replaced with isomeric tridecyl alcohol polyoxyethylene ether TO-10), the soft monomer, the hard monomer, the functional monomer, the silicone monomer, and the first portion of the initiator sodium sulfate are mixed and stirred to obtain a pre-emulsion;

[0058] Preparation of the bottom liquid: In a reaction kettle, ionized water and the second portion of the emulsifier (including the remaining portion of the anionic emulsifier AEROSOL A-102 and the remaining portion of the nonionic emulsifier TO-8) are mixed, the temperature is raised to 86-88 degrees, the second portion of the initiator sodium persulfate (and the remaining portion of the sodium persulfate) is added, and stirring is maintained. After reaction, the bottom liquid is obtained;

[0059] Perform the polymerization reaction by adding N% of the pre-emulsion as a seed emulsion to the bottom of the kettle, where N is the number shown in Table 1. Raise the reaction temperature to 86-88°C, and add the remaining pre-emulsion dropwise at a constant rate until the addition is complete, over a period of approximately 4-6 hours.

[0060] Post-treatment: After the addition is completed, keep warm for 30 minutes, continue to add the post-initiator, continue to keep warm for 90 minutes, cool to 70°C after the insulation is completed, and simultaneously add hydrogen peroxide aqueous solution and vitamin C aqueous solution, the addition time is 1 hour and keep warm for 1 hour, after the insulation is completed, cool to below 45°C, filter the material with a 200-mesh filter cloth, and adjust the pH to 7-8 with liquid alkali to obtain an acrylic emulsion for interior walls.

[0061] Example 1

[0062] This Example 1 uses the steps of the above-mentioned specific embodiment and the parameters shown in Table 1, but does not perform post-treatment. The remaining pre-emulsion is added dropwise at a constant speed until the addition is complete, which takes 4 hours.

[0063] Example 2

[0064] This Example 2 uses the steps of the above specific embodiment and the parameters shown in Table 1, but does not add a silane coupling agent. The remaining pre-emulsion is added dropwise at a constant speed until the addition is complete, which takes 4 hours.

[0065] Examples 3-5

[0066] Examples 3-5 used the steps of the above-mentioned specific embodiment and the parameters shown in Table 1. The remaining pre-emulsion was added dropwise at a uniform speed until the addition was complete, which took 4 hours.

[0067] Example 6

[0068] This Example 6 adopts the steps of the above-mentioned specific embodiment and the parameters shown in Table 1, but the remaining pre-emulsion is added dropwise at a uniform speed until the addition is completed, and the addition time is 6 hours.

[0069] Examples 7-8

[0070] This Example 7-8 uses the steps of the above-mentioned specific embodiment and the parameters shown in Table 1. The remaining pre-emulsion is added dropwise at a uniform speed until the addition is complete, and the addition time is 4 hours.

[0071] Table 1 Parameters of raw materials used in Examples 1-8 (unit: g)

[0072] The acrylic emulsions for interior walls obtained in Examples 1-8 were tested

[0073] The test method is as follows:

[0074] Particle size test: The particle sizes of the acrylic emulsions for interior walls of Examples 1-8 were tested using a Malvern particle size tester.

[0075] The odor rating assessment method is as follows: The acrylic emulsions for interior wall use of Examples 1-8 were placed in clean, frosted wide-mouth bottles, with the liquid level at half the height of the bottle. The bottles were then covered with glass lids and allowed to stand for 24 hours. Five odor assessors then evaluated the odor intensity. The odor intensity rating is coded on a scale of 0-5, with 0 being no odor, 1 being perceptible, non-disturbing, and mild, 2 being distinctly perceptible, non-disturbing, and moderate, 3 being distinctly perceptible, with a disturbing odor and a relatively strong intensity, 4 being distinctly perceptible, with a strongly disturbing odor and a very strong intensity, and 5 being unbearable.

[0076] Scrub Resistance Test: Interior wall latex paints were prepared using the interior wall acrylic emulsions of Examples 1-8. The specific formulations of the interior wall latex paints are shown in Table 2. The paints were mixed according to conventional methods. The scrub resistance of the interior wall latex paints was tested according to the scrub resistance test specified in GB / T 9756-2018.

[0077] Water whitening resistance test: The acrylic emulsions for interior walls of Examples 1-8 were scraped with a 100 nm wire rod and cured in a constant temperature and humidity room for one day. The water resistance of the varnish film was tested. The results showed that the film could not be rubbed off by hand and was not water-white.

[0078] Table 2 Interior wall paint formula

[0079] The experimental results are shown in Table 3:

[0080] Table 3

[0081] From the above results, it can be seen that the products of Examples 5 to 8 obtained have smaller emulsion particle size, lower emulsion odor, and excellent scrub resistance and water whitening resistance, indicating that the smaller the emulsion particle size, the better the scrub resistance of the product.

[0082] The products of Examples 1-4 exhibited larger emulsion particle size, poor scrub resistance and water whitening resistance, and a poor odor, which is related to the emulsion polymerization process. Compared to the product of Example 6, the products of Examples 3 and 4 exhibited larger emulsion particle size and poorer emulsion performance due to changes in the amount of emulsifier / seed emulsion / addition time.

[0083] The product of Example 1 was not post-treated, and the emulsion had a strong odor. The product of Example 2 did not add a silane coupling agent, and the emulsion had relatively poor scrub resistance and water whitening resistance.

[0084] It can be seen that by adding initiators and some redox agents for post-treatment in the late stage of emulsion polymerization, residual monomers can be eliminated, solving the odor problem to a certain extent. Introducing silicone monomers into the monomer raw materials can improve the mechanical properties of the emulsion to a certain extent.

[0085] Furthermore, the average particle size of the latex of the emulsion in the embodiment of the present invention is distributed within 120 nm, and the smaller the particle size, the better the mechanical properties of the emulsion, given similar formula components. Small-particle emulsions are more densely polymerized latex particles, and their stability is greatly improved. Moreover, when small-particle emulsions are applied to interior wall paints, they are more conducive to film formation and adhesion, thereby improving the scrub resistance and water whitening resistance of the product. Emulsifiers are one of the key factors affecting the latex particles of emulsion polymers, and the site of emulsion polymerization is micelles. The present invention uses anionic and nonionic composite emulsifiers, which are mixed with monomers to form micelles. When the emulsifier is high, more micelles are formed, increasing the polymerization site and reducing the polymer particle size. Conversely, if the emulsifier used in the amount of the present invention is not used, when the emulsifier is low, fewer micelles are formed and the polymer particle size becomes larger. However, too little emulsifier is not conducive to the emulsion polymerization and affects the performance of the emulsion. The raw materials of the present invention use a larger amount of emulsifier, and the monomers are emulsified more thoroughly by the emulsifier.

[0086] In addition, the preparation method of the present invention uses a seed emulsion preparation process. By controlling the selection amount of seed emulsion, the emulsion particle size can be controlled. The emulsion particle size changes with the change of seed amount. The smaller the seed amount, the larger the emulsion particle size; the more seed amount, the smaller the emulsion particle size. The particle size and distribution of the emulsion can be effectively controlled by seeding.

[0087] In summary, the acrylic emulsion for interior walls of the present invention is prepared by combining monomer formulas, adding a relatively large amount of anionic and nonionic emulsifiers, controlling the amount of seed emulsion added, and adopting a silicon addition process for polymerization. The obtained emulsion not only has excellent environmental performance and low odor, but also has excellent mechanical properties and good compatibility with substrates, so that the emulsion paint has excellent scrub resistance and water whitening resistance.

[0088] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples. Within the scope of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0089] The embodiments of the present invention are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included in the scope of protection of the present invention.

Claims

1. An acrylic emulsion for interior walls, characterized in that: The raw materials of the acrylic emulsion for interior walls include emulsifier, water, initiator and monomer; The monomers include soft monomers, hard monomers, functional monomers and silicone monomers; and, The average particle size of the particles of the acrylic emulsion for interior walls is ≤120nm; in, The soft monomer is an acrylic soft monomer with a Tg range of -70°C to -20°C; The hard monomer is styrene; The functional monomer includes one or a combination of acrylic acid, methacrylic acid, acrylamide and methacrylamide.

2. The acrylic emulsion for interior walls according to claim 1, characterized in that: The soft monomer is butyl acrylate and / or isooctyl acrylate; And / or, the organic silicon monomer is selected from one or a combination of vinyl trimethoxy silane, γ-methacryloxypropyl trimethoxy silane and γ-(2,3-epoxypropyl) propyl trimethoxy silane.

3. The acrylic emulsion for interior walls according to claim 1, characterized in that: The emulsifier includes anionic emulsifier and nonionic emulsifier; The anionic emulsifier includes one or a combination of fatty alcohol polyoxyethylene ether succinate, sodium dodecyl diphenyl oxide disulfonate and sodium allyloxy hydroxypropyl sulfonate; And / or, the nonionic emulsifier includes one or more combinations of fatty alcohol polyoxyethylene ether emulsifiers, fatty acid polyoxyethylene ester emulsifiers and polyoxyethylene alkylamine emulsifiers.

4. The acrylic emulsion for interior walls according to claim 1, characterized in that: The raw materials of the acrylic emulsion for interior walls include, by weight, 1-15 parts of emulsifier, 0.1-5 parts of initiator, 25-40 parts of soft monomer, 30-50 parts of hard monomer, 1-3 parts of functional monomer and 2-3 parts of organosilicon monomer, and the amount of water is 85wt%-115wt% of the total weight of the monomers; And / or, the initiator includes one or a combination of ammonium persulfate, sodium persulfate and potassium persulfate.

5. The acrylic emulsion for interior walls according to claim 3, characterized in that: The fatty alcohol polyoxyethylene ether succinic sulfonate is a sulfonate obtained by sulfonating fatty alcohol with polyoxyethylene; And / or, the nonionic emulsifier is a fatty alcohol polyoxyethylene ether emulsifier.

6. The acrylic emulsion for interior walls according to claim 1, characterized in that: The raw materials of the acrylic emulsion for interior walls also include an oxidizing agent and a reducing agent; The oxidant is tert-butyl hydroperoxide or hydrogen peroxide; the amount of the oxidant added is 0.1wt%-1wt% of the total weight of the monomer; And / or, the reducing agent is sodium salt of vitamin C and / or vitamin C; the added amount of the reducing agent is 0.1wt%-1wt% of the total weight of the monomer.

7. The acrylic emulsion for interior walls according to claim 1, characterized in that: The raw materials of the acrylic emulsion for interior walls also include a post-initiator; The post-initiator includes one or a combination of ammonium persulfate, sodium persulfate and potassium persulfate; the amount of the post-initiator used is 0.05wt%-1wt% of the total weight of the monomer.

8. The method for preparing the acrylic emulsion for interior walls according to any one of claims 1 to 7, comprising the following steps: Mixing the first part of water, the first part of emulsifier, the monomer and the first part of initiator to react and obtain a pre-emulsion; The second part of water and the second part of emulsifier are mixed, and after heating, the second part of initiator is added, and the bottom liquid of the kettle is obtained after reaction; The pre-emulsion accounting for 6%-10% of the total weight of the pre-emulsion is added as seed emulsion to the bottom liquid of the kettle. After the reaction temperature rises, the remaining pre-emulsion is dripped at a uniform speed until the dripping is completed. After post-treatment, the pH value is adjusted to 7-8 to obtain acrylic emulsion for interior walls.

9. The preparation method according to claim 8, characterized in that: The said heating up means that the temperature is raised to 85-90°C; And / or, the post-treatment is to continue to drop the post-initiator after the pre-emulsion is added, keep the temperature for 25-90 minutes, and then drop the oxidizing agent and the reducing agent at the same time.

10. The preparation method according to claim 8, characterized in that: The amount of the first part of water is 50%-70% of the total weight of the monomers; the first part of the emulsifier includes anionic emulsifiers and nonionic emulsifiers, and the amount of the anionic emulsifier is The amount of the nonionic emulsifier is 1.5-2% of the total weight of the monomers; the amount of the first part of the initiator is 0.05%-0.15% of the total weight of the monomers; And / or, the amount of the second part of water is 35%-45% of the total weight of the monomers; the second part of emulsifier includes anionic emulsifier and nonionic emulsifier, the amount of the anionic emulsifier is 2%-3.5% of the total weight of the monomers, and the amount of the nonionic emulsifier is 2%-3% of the total weight of the monomers; the amount of the second part of initiator is 0.5%-1% of the total weight of the monomers.

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