Method for preparing a styrene-acrylic emulsion as a wallpaper adhesive medium

Abstract

The application discloses a preparation method of a styrene-acrylic emulsion used as a wallpaper sticking medium. The raw material of the styrene-acrylic emulsion comprises the following components in the form of weight fractions: 30-50 parts of acrylic ester soft monomers, 40-60 parts of hard monomers, 3-6 parts of cross-linking monomers, 1.5-2 parts of emulsifiers, 0.3-0.6 parts of initiators, and 0.1-0.4 parts of pH buffers. The hard monomers comprise acrylic ester hard monomers, styrene and functional hard monomers. The functional hard monomers comprise acrylic acid and acrylonitrile. The cross-linking monomers comprise epoxy-based monomers and cross-linking monomer A, and the cross-linking monomer A is a monomer containing amino groups and / or hydroxyl groups. The styrene-acrylic emulsion prepared by the method has certain flexibility, high solid content and extremely fine particle size, has good adhesion and sealing properties on cement-based materials, shows good water resistance and alkali resistance, is a relatively environment-friendly styrene-acrylic emulsion, and has extremely high industrial application prospect and popularization value.

Description

[0001] This application is a divisional application, the original application number is 202210320086.0, the original application date is March 29, 2022, and the entire contents of the original application are incorporated herein by reference. TECHNICAL FIELD

[0002] The present application belongs to the field of styrene-acrylic emulsion, and particularly relates to a preparation method of a styrene-acrylic emulsion used as a wallpaper pasting medium. BACKGROUND

[0003] Wallpaper pasting is a decoration process that has appeared in the past decade. It is a process of pasting various patterns and designs of wallpaper on the wall in an orderly and regular manner by heating. After pasting the wallpaper, no further treatment is needed, and the room with pasted wallpaper gives people a comfortable, soft and solemn feeling. It is favored by more and more consumers due to its excellent performance and pleasing appearance.

[0004] A medium treatment is usually needed between the wallpaper and the wall, which aims to close the surface of the cement-based wall to prevent water seepage, efflorescence and other phenomena, which will cause different degrees of damage to the wallpaper and affect the aesthetic effect. The products available on the market as pasting media are of varying quality. Some use ordinary styrene-acrylic emulsion as the wallpaper pasting medium, add water and brush, and some use 801 glue mixed with emulsion for brushing. These products do not have good sealing effect on the wall to some extent, and cannot effectively seal the wall when the wall is wet or seeps water, thereby causing damage to the wallpaper, such as peeling, efflorescence and blooming. Many pasting medium products do not consider environmental protection, such as containing alkylphenol polyoxyethylene ether compounds (APEO) or excessive free formaldehyde, which will have different degrees of impact on the environment and people.

[0005] Therefore, there is an urgent need in the art to develop a wallpaper emulsion that has good sealing effect on the wall, can ensure firm pasting of the wallpaper, is not easy to peel off or bloom, and is environmentally friendly; and can still maintain good sealing effect when the wall is wet or seeps water. SUMMARY

[0006] The present application aims to solve the technical problem of overcoming the poor sealing effect of the existing wallpaper paste medium on the wall to some extent, and providing a kind of styrene-acrylic emulsion, its raw material composition and its preparation method and application. The styrene-acrylic emulsion prepared by the present application belongs to a product with certain flexibility, high solid content and extremely fine particle size, which can be prepared into soft glue and hard glue according to actual needs, has good adhesion and sealing property to cement base material, shows good water resistance and alkali resistance, the water resistance is much higher than that of the emulsion products on the market, and the VOC release amount is low, which belongs to a relatively environmentally friendly styrene-acrylic emulsion with high industrial application prospect and popularization value.

[0007] The present application solves the above technical problems by adopting the following technical solutions:

[0008] The present application provides a raw material composition of a styrene-acrylic emulsion, which comprises the following components in weight percentage: 30-50 parts of acrylic ester soft monomer, 40-60 parts of hard monomer, 3-6 parts of crosslinking monomer, 1.5-2 parts of emulsifier, 0.3-0.6 parts of initiator, and 0.1-0.4 parts of pH buffer.

[0009] The hard monomer comprises acrylic ester hard monomer, styrene and functional hard monomer; the functional hard monomer comprises acrylic acid and acrylonitrile; the crosslinking monomer comprises epoxy-based monomer and crosslinking monomer A, and the crosslinking monomer A is a monomer containing amino and / or hydroxyl groups.

[0010] In some embodiments, the acrylic ester soft monomer can include one or more of ethyl acrylate, n-butyl acrylate, n-octyl acrylate, isooctyl acrylate, lauryl acrylate, isooctyl methacrylate, and 2-hydroxyethyl acrylate, preferably n-butyl acrylate and / or isooctyl acrylate.

[0011] In some embodiments, the acrylic ester hard monomer can include one or more of methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, hexyl methacrylate, isobornyl methacrylate, isobornyl acrylate, isobutyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate, preferably methyl methacrylate.

[0012] It is found in the development process that when the functional hard monomer does not contain at least one of acrylic acid and acrylonitrile, the particle size becomes coarse, the stability is poor, and the sealing effect is reduced.

[0013] In some embodiments, the epoxy-based monomer can include epoxypropyl methacrylate.

[0014] In some embodiments, the crosslinking monomer A can include one or more of an amino benzoic acid, an amino hydroxy benzoic acid, an amino carboxy aniline, and a fatty chain dihydroxy acid.

[0015] In some embodiments, the amino benzoic acid can include 3,5-diamino benzoic acid.

[0016] In some embodiments, the amino hydroxy benzoic acid can include 3-amino-4-hydroxy benzoic acid.

[0017] In some embodiments, the fatty chain dihydroxy acid can include 2,2-dimethylol propionic acid.

[0018] In some embodiments, the emulsifier can include any one or more of a fatty alcohol polyoxyethylene ether, an isomeric alcohol polyoxyethylene ether, and a fatty alcohol polyoxyethylene ether sulfate.

[0019] In some embodiments, the fatty alcohol polyoxyethylene ether sulfate can include a fatty alcohol polyoxyethylene ether sodium sulfate and / or a fatty alcohol polyoxyethylene ether ammonium sulfate.

[0020] In some embodiments, the emulsifier does not include an alkyl phenol polyoxyethylene ether.

[0021] In some embodiments, the initiator can include a persulfate and / or an azo initiator.

[0022] In some embodiments, the persulfate can include ammonium persulfate.

[0023] In some embodiments, the pH buffer can include sodium bicarbonate and / or sodium carbonate.

[0024] In some embodiments, the weight fraction of the acrylate hard monomer can be 30-50 parts, preferably 40-45 parts.

[0025] In some embodiments, the weight fraction of the styrene can be 5-15 parts, preferably 5-10 parts.

[0026] In some embodiments, the weight fraction of the functional hard monomer can be 5-12 parts, preferably 9-10 parts.

[0027] In some embodiments, the weight fraction ratio of the acrylic acid to the acrylonitrile can be 1:(1-2.5), preferably 1:(1.5-2.3).

[0028] In some embodiments, the molar ratio of the epoxy monomer to the crosslinking agent A can be (1.5-3.5):1, preferably (2-2.7):1, for example 2.3:1.

[0029] In some embodiments, the weight fraction of the acrylate soft monomer is preferably 45-50 parts.

[0030] In some embodiments, the weight fraction of the cross-linking monomer is preferably 3-4.3 parts.

[0031] In some embodiments, the weight fraction of the initiator is preferably 0.3-0.55 parts.

[0032] In some embodiments, the weight fraction of the pH buffer is preferably 0.1-0.2 parts.

[0033] In some embodiments, the raw material composition of the styrene-acrylic emulsion can further comprise a solvent.

[0034] In some embodiments, the solvent can be a solvent commonly used in the art, preferably water, and more preferably deionized water.

[0035] In some embodiments, the weight fraction of the solvent can be conventional in the art, preferably 50-100 parts, and more preferably 70-90 parts.

[0036] The present application also provides a preparation method of a styrene-acrylic emulsion, which comprises a raw material as described above, and the preparation method comprises the following steps:

[0037] (1) sequentially adding the acrylic ester soft monomer, the hard monomer, and the cross-linking monomer to the mixture of the emulsifier, the pH buffer, and the solvent, mixing to obtain a pre-emulsion;

[0038] (2) mixing and reacting part of the pre-emulsion with part of the initiator to obtain a seed emulsion;

[0039] (3) mixing and reacting the seed emulsion, the remaining part of the pre-emulsion, and the remaining part of the initiator.

[0040] In step (1), it is found in the development process that the acrylic ester soft monomer, the hard monomer, and the cross-linking monomer need to be added in sequence, otherwise the emulsification effect will be unsatisfactory, which can easily lead to stratification of the system.

[0041] In step (1), the preparation method of the mixture of the emulsifier, the pH buffer, and the solvent can be conventional in the art, and the emulsifier, the pH buffer, and the solvent are generally mixed uniformly.

[0042] In step (1), the mixing can be performed under stirring according to the conventional method in the art, and the stirring speed can be conventional in the art, preferably 200-300 rpm, and more preferably 200-250 rpm.

[0043] The mixing time in step (1) can be conventional for such operation in the art, and generally can be sufficient to emulsify the system, preferably 20-30 minutes.

[0044] The mixing temperature in step (1) can be conventional for such operation in the art, and preferably is 25-30°C.

[0045] In step (2), part of the pre-emulsion can be mixed with solvent before use.

[0046] The weight ratio of part of the pre-emulsion to the solvent can be 1:(2-4), preferably 1:(3-4).

[0047] The mixing can be performed under stirring at a speed of 100-150 rpm, preferably 100-120 rpm.

[0048] The mixing temperature can be conventional for such operation in the art, and preferably is 75-80°C, more preferably 78-80°C.

[0049] The mixing time can be conventional for such operation in the art, and generally can be sufficient to mix the system uniformly.

[0050] The mixing reaction time in step (2) can be conventional for such operation in the art, and generally can be sufficient to emulsify the system, preferably 0.5-5 hours, more preferably 0.5-1 hour.

[0051] The mixing reaction temperature in step (2) can be conventional for such operation in the art, and preferably is 75-80°C, more preferably 78°C.

[0052] The mixing reaction time in step (3) can be conventional for such operation in the art, and preferably is 0.5-3 hours, more preferably 1 hour.

[0053] The mixing reaction temperature in step (3) can be conventional for such operation in the art, and preferably is 85-88°C.

[0054] The mixing reaction in step (3) can further include any one or more of the following operations: cooling, adjusting the pH value of the system to 7.5-8, and filtration.

[0055] The cooling conditions and methods can be conventional in the art, and generally can be cooling to 40-50°C.

[0056] The method for adjusting the pH value of the system to 7.5-8 can be conventional in the art, and generally can be adjusting the pH value of the system to 7.5-8 using ammonia.

[0057] In some embodiments, the weight ratio of the part of the pre-emulsion in step (2) to the rest of the pre-emulsion in step (3) can be 1:(7-16), preferably 1:(9-14).

[0058] In some embodiments, the part of the initiator in step (2) and / or the rest of the initiator in step (3) can be added in the form of an initiator solution according to the conventional practice in the art.

[0059] In the initiator solution, the initiator can account for 10-20%, preferably 15%, of the initiator solution.

[0060] In the initiator solution, the initiator can account for 10-20%, preferably 15%, of the initiator solution.

[0061] In some embodiments, the weight ratio of the part of the initiator in step (2) to the rest of the initiator in step (3) can be 1:(2-3), preferably 1:(2-2.6).

[0062] The present application also provides a styrene-acrylic emulsion prepared by the method for preparing a styrene-acrylic emulsion as described above.

[0063] The present application also provides the use of the styrene-acrylic emulsion as described above as a raw material in the preparation of wallpaper paste medium, interior wall paint and exterior wall paint.

[0064] The present application also provides a wallpaper paste medium comprising the styrene-acrylic emulsion as described above.

[0065] In some embodiments, the wallpaper paste medium can further comprise a film-forming aid and / or a thickening agent.

[0066] In the wallpaper paste medium, the film-forming aid can account for 3-8% of the wallpaper paste medium according to the conventional practice in the art.

[0067] The reagents and raw materials used in the present application are commercially available.

[0068] The positive progress effect of the present application is that the prepared styrene-acrylic emulsion for preparing wallpaper sticking medium belongs to a product with certain flexibility, high solid content and extremely fine particle size, and can be prepared into soft glue and hard glue according to actual requirements; meanwhile, the prepared styrene-acrylic emulsion has good adhesion and sealing property to cement base material without using alkyl phenol polyoxyethylene ether, shows good water resistance and alkali resistance, and the water resistance is much higher than that of the emulsion products on the market, and the release amount of VOC including formaldehyde is low, which belongs to a relatively environment-friendly styrene-acrylic emulsion, and has extremely high industrial application prospect and popularization value. DETAILED DESCRIPTION

[0069] The present application will be further described by way of examples, but the present application is not limited to the scope of the examples. The experimental methods in the following examples without specific conditions are selected according to conventional methods and conditions, or according to the instructions of the commodity.

[0070] Example 1

[0071] The present embodiment provides a styrene-acrylic emulsion with good water resistance and alkali resistance as a wallpaper sticking medium, and the types and weight fractions of each component in the raw materials are shown in Table 1:

[0072] Table 1

[0073]

[0074] The preparation method of the styrene-acrylic emulsion includes the following steps:

[0075] (1) 0.3 parts of initiator is dissolved in 1.7 parts of deionized water to obtain an initiator aqueous solution; 1.5 parts of fatty alcohol polyoxyethylene ether ammonium sulfate emulsifier and 0.1 parts of sodium bicarbonate are added to 40 parts of deionized water, mixed until completely dissolved, then 30 parts of n-butyl acrylate and 15 parts of isooctyl acrylate are added, followed by 40 parts of methyl methacrylate, 10 parts of styrene, 4 parts of acrylic acid and 6 parts of acrylonitrile, and finally 2 parts of glycidyl methacrylate and 0.9 parts of 3,5-diaminobenzoic acid, after stirring at a speed of 200 rpm for 30 min, a pre-emulsion is obtained;

[0076] (2) 15 parts of the pre-emulsion obtained in step 1 and 30 parts of deionized water are added to a condensing stirring device, and after stirring at a speed of 100 rpm to heat to 78℃, one-third of the initiator aqueous solution obtained in step 1 (wherein the initiator is 0.1 parts) is weighed, and mixed at 78℃ for 0.5 h to obtain a blue phase seed emulsion;

[0077] (3) In 2h, the remaining part of the pre-emulsion obtained in step 1 and the remaining part of the initiator aqueous solution (wherein the initiator is 0.2 parts) obtained in step 1 were added into the blue phase seed emulsion obtained in step 2 at the same time, and after being heated to 85℃, the reaction was carried out for 1h, and after being cooled to 40℃, the pH was adjusted to 7.5 with ammonia water, and after being stirred uniformly, the product was filtered and discharged, thereby obtaining the wallpaper paste medium styrene-acrylic emulsion.

[0078] Example 2

[0079] This example provides a styrene-acrylic emulsion with good water resistance and alkali resistance, which can be used as a wallpaper paste medium. The types and weight fractions of the components in the raw materials are shown in Table 2:

[0080] Table 2

[0081]

[0082] The preparation method of the styrene-acrylic emulsion includes the following steps:

[0083] (1) According to the weight parts, 0.55 parts of initiator was dissolved in 3.1 parts of deionized water to obtain an initiator aqueous solution; 2 parts of fatty alcohol polyoxyethylene ether sodium sulfate emulsifier and 0.2 parts of sodium bicarbonate were added into 45 parts of deionized water and mixed until completely dissolved, then 40 parts of n-butyl acrylate and 5 parts of isooctyl acrylate were added, followed by the addition of 45 parts of methyl methacrylate, 5 parts of styrene, 3 parts of acrylic acid and 7 parts of acrylonitrile, and finally 3 parts of glycidyl methacrylate and 1.3 parts of 3-amino-4-hydroxybenzoic acid were added. After stirring at a speed of 250 rpm for 30 min, a pre-emulsion was obtained;

[0084] (2) 10 parts of the pre-emulsion obtained in step 1 and 40 parts of deionized water were added into a condensing stirring device, and after being stirred at a speed of 120 rpm and heated to 80℃, a part of the initiator aqueous solution (wherein the initiator is 0.15 parts) obtained in step 1 was added, and the mixture was reacted at 80℃ for 1h to obtain a blue phase seed emulsion;

[0085] (3) In 3h, the remaining part of the pre-emulsion obtained in step 1 and the remaining part of the initiator aqueous solution (wherein the initiator is 0.4 parts) obtained in step 1 were added into the blue phase seed emulsion obtained in step 2 at the same time, and after being heated to 88℃, the reaction was carried out for 1h, and after being cooled to 50℃, the pH was adjusted to 8 with ammonia water, and after being stirred uniformly, the product was filtered and discharged, thereby obtaining the wallpaper paste medium styrene-acrylic emulsion.

[0086] Comparative Example 1

[0087] The product number of the styrene-acrylic emulsion produced by Zhejiang Xinli Chemical Co., Ltd. is XL200.

[0088] Comparative Example 2

[0089] A styrene-acrylic emulsion is provided, comprising the following raw materials by weight parts: 52 parts of acrylic ester soft monomer, 45 parts of acrylic ester hard monomer, 2.9 parts of crosslinking monomer, 1.5 parts of emulsifier, 0.3 parts of initiator, 0.1 parts of pH buffer, 71.7 parts of water.

[0090] The acrylic ester soft monomer is a mixture of n-butyl acrylate and isooctyl acrylate. The acrylic ester hard monomer is methyl methacrylate. The crosslinking monomer is a mixture of diacetone acrylamide and diamino benzoic acid, with a molar ratio of 2:1. The emulsifier is fatty alcohol polyoxyethylene ether ammonium sulfate, the initiator is ammonium persulfate, and the pH buffer is sodium bicarbonate.

[0091] A method for preparing a styrene-acrylic emulsion, comprising the following steps:

[0092] Step one: dissolve the initiator in 1.7 parts of deionized water to obtain an initiator aqueous solution; add 1.5 parts of fatty alcohol polyoxyethylene ether ammonium sulfate emulsifier and 0.1 parts of sodium bicarbonate to 40 parts of deionized water, mix until completely dissolved, then add 47 parts of n-butyl acrylate, 5 parts of isooctyl acrylate, 45 parts of methyl methacrylate, and 2.9 parts of crosslinking monomer, stir at a speed of 200 rpm for 30 minutes to obtain a pre-emulsion;

[0093] Step two: weigh 17.6wt% of the pre-emulsion obtained in step one, and add 30 parts of deionized water to a condensing stirring device, stir at a speed to heat to 78℃, then weigh 0.1 parts of the initiator aqueous solution obtained in step one, and react at 78℃ for 0.5h to obtain a blue phase seed emulsion;

[0094] Step three: within 2h, add the remaining pre-emulsion obtained in step one and 0.2 parts of the initiator aqueous solution to the blue phase seed emulsion obtained in step two, heat to 85℃, then react for 1h, cool to 40℃, adjust the pH to 7.5 with ammonia water, stir uniformly, then filter and discharge to obtain a pure acrylic emulsion for fabric foaming coating.

[0095] Comparative Example 3

[0096] This example provides a styrene-acrylic emulsion with good water and alkali resistance, which can be used as a wallpaper paste medium. The types and weight fractions of each component in the raw materials are shown in Table 3:

[0097] Table 3

[0098]

[0099] A method for preparing a styrene-acrylic emulsion, comprising the following steps:

[0100] (1) According to parts by weight, 0.5 initiator was dissolved in 2.8 parts of deionized water to obtain an initiator aqueous solution; 2 parts of fatty alcohol polyoxyethylene ether sodium sulfate emulsifier and 0.2 parts of sodium bicarbonate were added to 50 parts of deionized water and mixed until completely dissolved, then 13 parts of n-butyl acrylate and 24 parts of isooctyl acrylate were added, followed by 45 parts of methyl methacrylate, 10 parts of styrene, 2 parts of acrylic acid and 8 parts of acrylonitrile, and finally 4 parts of glycidyl methacrylate and 1.5 parts of 2,2-dimethylol propionic acid, after stirring at a speed of 300 rpm for 20 min, a pre-emulsion was obtained;

[0101] (2) 13 parts of the pre-emulsion obtained in step 1 and 40 parts of deionized water were added to a condensing stirring device, and after stirring at a speed of 150 rpm to heat to 80°C, a part of the initiator aqueous solution obtained in step 1 (wherein the initiator is 0.2 parts) was added and mixed at 80°C for 1 h to obtain a blue phase seed emulsion;

[0102] (3) The remaining part of the pre-emulsion obtained in step 1 and the remaining part of the initiator aqueous solution obtained in step 1 (wherein the initiator is 0.3 parts) were simultaneously added to the blue phase seed emulsion obtained in step 2 within 3 h, and after heating to 88°C, the reaction was carried out for 1 h, then the temperature was lowered to 50°C, the pH was adjusted to 8 with ammonia water, and after stirring uniformly, the product was filtered and discharged to obtain a wallpaper adhesive medium phenolic emulsion.

[0103] Effect Example 1

[0104] Appearance color test: The phenolic emulsion prepared in Examples 1-2 above and the commercially available phenolic emulsion in Comparative Example 1 were evaluated for appearance color, and the results showed that the phenolic emulsion prepared in Examples 1-2 above was milky white with a slight blue color after being applied to the wall, and the commercially available product in Comparative Example 1 was milky white or milky white with a blue phase after being applied to the wall.

[0105] Water and alkali resistance test: The phenolic emulsion prepared in Examples 1-3 above, the commercially available phenolic emulsion in Comparative Example 1, the product prepared in Comparative Example 2 and Comparative Example 3 were applied to the same cement board with a thickness of 0.2 mm, and after being placed at room temperature for 24 h, the samples were placed in tap water and 10% sodium hydroxide aqueous solution, respectively, and the time for abnormality, flooding and peeling of the paint film was observed, with a test period of 48 h, and the results are shown in Table 4; wherein three parallel experiments were set for each group in Examples 1 and 2.

[0106] Table 4

[0107]

[0108]

[0109] From the above experimental results, it can be seen that the prepared wallpaper pasting medium styrene-acrylic emulsion has no abnormality in film immersion in water for 48 h, only slightly bluing; in the alkali resistance experiment, there is also no abnormality for 7 days, and the water resistance and alkali resistance performance are much higher than that of the styrene-acrylic emulsion products on the market and the products prepared in the examples 2-3.

[0110] Finally, it should also be noted that the term "comprising" or "including" or any other variant thereof in the present application is intended to cover non-exclusive inclusion, so that a process, method, article or apparatus including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such a process, method, article or apparatus.

[0111] Although the present disclosure has been disclosed by the description of specific embodiments of the present disclosure above, it should be understood that those skilled in the art can design various modifications, improvements or equivalents of the present disclosure within the spirit and scope of the appended claims. These modifications, improvements or equivalents should also be considered to be included in the scope of protection required by the present disclosure.

Claims

1. A method for preparing a styrene-acrylic emulsion as a wallpaper adhesive medium, characterized by, The raw materials include the following components in parts by weight: 30-50 parts of acrylate soft monomer, 40-60 parts of hard monomer, 3-6 parts of crosslinking monomer, 1.5-2 parts of emulsifier, 0.3-0.6 parts of initiator, 0.1-0.4 parts of pH buffer; The hard monomer is the sum of acrylate hard monomer, styrene and functional hard monomer, The functional hard monomer is the sum of acrylic acid and acrylonitrile; The crosslinking monomer is the sum of epoxy-based monomer and crosslinking monomer A, The epoxy-based monomer is epoxypropyl methacrylate, The crosslinking monomer A is one or more of aminobenzoic acid, aminohydroxybenzoic acid, aminocarboxybenzene and fatty chain dihydroxy acid; The preparation method comprises the following steps: (1) The acrylate soft monomer, the hard monomer and the crosslinking monomer are sequentially added to the mixture of the emulsifier, the pH buffer and the solvent, mixed, and a pre-emulsion is obtained; (2) Part of the pre-emulsion is mixed with part of the initiator to prepare a seed emulsion; (3) The seed emulsion, the remaining part of the pre-emulsion and the remaining part of the initiator are mixed and reacted.

2. The method for preparing a styrene-acrylic emulsion as a wallpaper pasting medium as described in claim 1, characterized in that, The preparation method satisfies at least one of the following conditions: In step (1), the mixing is carried out under stirring, and the stirring speed is 200-300 rpm; In step (1), the mixing time is 20-30 min, and the mixing temperature is 25-30℃; In step (2), part of the pre-emulsion is mixed with solvent before use; the weight ratio of part of the pre-emulsion to the solvent is 1:(2-4), the mixing is carried out under stirring, the mixing stirring speed is 100-150 rpm, and the mixing stirring temperature is 75-80℃; In step (2), the mixing reaction time is 0.5-5 h, and the mixing reaction temperature is 75-80℃; In step (3), the mixing reaction time is 0.5-3 h, and the mixing reaction temperature is 85-88℃; In step (3), the mixing reaction operation is further followed by any one or more of the following operations: cooling, adjusting the pH of the system and filtering; the cooling is cooling to 40-50℃; the pH of the system is adjusted to 7.5-8 using ammonia.

3. The method for preparing a styrene-acrylic emulsion as a wallpaper pasting medium as described in claim 1, characterized in that, The preparation method satisfies at least one of the following conditions: In step (2), the weight ratio of part of the pre-emulsion to the remaining part of the pre-emulsion in step (3) is 1:(7-16); In step (2), part of the initiator and / or the remaining part of the initiator in step (3) is added in the form of an initiator solution; the solvent in the initiator solution is water; in the initiator solution, the mass percentage of the initiator in the initiator solution is 10%-20%; In step (2), the weight ratio of part of the initiator to the remaining part of the initiator in step (3) is 1:(2-3).

4. The method for preparing a styrene-acrylic emulsion as a wallpaper pasting medium as described in claim 1, characterized in that, At least one of the following conditions is satisfied: The acrylate soft monomer is one or more of ethyl acrylate, n-butyl acrylate, n-octyl acrylate, iso-octyl acrylate, lauryl acrylate, iso-octyl methacrylate, 2-hydroxyethyl acrylate; The acrylate hard monomer is one or more of methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, hexyl methacrylate, iso-borneol methacrylate, iso-borneol acrylate, iso-butyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate; In the crosslinking monomer A, the amino benzoic acid is 3,5-diamino benzoic acid, the amino hydroxy benzoic acid is 3-amino-4-hydroxy benzoic acid, and the fatty chain dihydroxy acid is 2,2-dimethylol propionic acid; The emulsifier is one or more of fatty alcohol polyoxyethylene ether, isomeric alcohol polyoxyethylene ether and fatty alcohol polyoxyethylene ether sulfate; The emulsifier does not include alkyl phenol polyoxyethylene ether; The initiator is a persulfate and / or azo initiator; The pH buffer is sodium bicarbonate and / or sodium carbonate.

5. The method for preparing a styrene-acrylic emulsion as a wallpaper pasting medium as described in claim 1, characterized in that, At least one of the following conditions is met: The weight fraction of the acrylate hard monomer is 30-50 parts; The weight fraction of the styrene is 5-15 parts; The weight fraction of the functional hard monomer is 5-12 parts; The weight fraction ratio of the acrylic acid to the acrylonitrile is 1:(1-2.5); The molar ratio of the epoxy monomer to the crosslinking monomer A is (1.5-3.5):1; The weight fraction of the acrylate soft monomer is 45-50 parts; The weight fraction of the crosslinking monomer is 3-4.3 parts; The weight fraction of the initiator is 0.3-0.55 parts; The weight fraction of the pH buffer is 0.1-0.2 parts.

6. The method for preparing a styrene-acrylic emulsion as a wallpaper pasting medium as described in claim 1, characterized in that, The solvent is water; the weight fraction of the solvent is 50-100 parts.

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