A water-based stone-like emulsion and a method for preparing the same

Abstract

The application discloses a kind of water-based stone-like emulsion and preparation method thereof, belong to building coating field, raw material includes 15-30 parts of acrylic acid and its related ester monomer, 10-20 parts of styrene monomer, 2-4 parts of emulsifier, 0.2-0.6 parts of initiator and 1-3 parts of functional monomer and 54-59 parts of water by weight, the preparation process of water-based stone-like emulsion prepared by the application is easy to control, synthesis reaction is stable, apparent particle size is moderate, and the amount of slag is low, the mechanical stability of water-based stone-like emulsion in later period is enhanced by the synthesis means of the process.

Description

A water-based imitation stone emulsion and its preparation method Technical Field

[0001] This invention belongs to the field of architectural coatings, and specifically relates to a water-based stone-like emulsion and its preparation method. Background Technology

[0002] With the arrival of the global low-carbon era, the building materials industry is bound to develop in depth towards low-carbon, energy-saving, environmental protection, and health, in order to realize a better life for mankind. Low-carbon economic and social services have become a social responsibility.

[0003] Water-based stone-like paint emulsion, also known as water-based real stone paint emulsion, is mainly formulated by mixing natural stone powder of various colors with polymer emulsion. When sprayed on the exterior walls of buildings, it closely resembles marble and granite, making it an ideal material to replace natural stone decorative surfaces. However, currently, the preparation of stone-like paint suffers from poor quality sand powder. During high-speed stirring and dispersion, the fluidity deteriorates, and the sand powder agglomerates, resulting in poor emulsion mechanical stability during the paint-making process, ultimately leading to paint failure. This is due to the shearing and damaging effect of sand powder impurities and the dispersion disc on the latex particles, causing emulsion demulsification. The main reason for this is that the surface segments of the synthesized latex microparticles contain a large number of hydrophobic functional groups, resulting in relatively poor latex particle stability. Once subjected to high shear forces, the stable structure of the latex particles is destroyed, causing not only the emulsion to lose its adhesive properties but also rendering other simultaneously produced paint raw materials unusable. Summary of the Invention

[0004] This invention provides an aqueous imitation stone emulsion and its preparation method to solve the technical problem mentioned above: the latex particles have relatively poor stability, and their stable structure is destroyed when subjected to high shear forces, resulting in the emulsion losing its adhesive properties and rendering the paint raw materials unusable.

[0005] The present invention solves the above-mentioned technical problems by adopting the following technical solutions:

[0006] This invention provides an aqueous imitation stone emulsion and its preparation method. The raw materials include, by weight, 15-30 parts of acrylic acid and related ester monomers, 10-20 parts of styrene monomers, 2-4 parts of emulsifier, 0.2-0.6 parts of initiator, 1-3 parts of functional monomer, and 54-59 parts of water, wherein the functional monomer is a silane functional monomer containing vinyl groups.

[0007] Preferably, the acrylic acid and its ester monomers are composed of hard monomers and soft monomers, wherein the hard monomers include acrylic acid, acrylamide, methacrylic acid, and methyl methacrylate; and the soft monomers include at least one of isooctyl acrylate, n-butyl acrylate, isobutyl acrylate, and ethyl acrylate.

[0008] More preferably, the weight ratio of the hard monomer to the soft monomer is 0.8 to 1:1. Preferably, the styrene monomer may include at least one of styrene, 3-chlorostyrene, 4-chlorostyrene, and p-chlorostyrene.

[0009] Preferably, the ethoxylated silane functional monomer includes one of vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltrichlorosilane, and vinyltributylone oxime silane.

[0010] Preferably, the emulsifier comprises at least one of alkyl alcohol ether phosphate, branched alkyl alcohol ether phosphate ammonium salt, branched alkyl alcohol phosphate sodium salt, alkyl alcohol block polyether emulsifier, and alkyl sulfonate sodium.

[0011] A method for preparing an aqueous imitation stone emulsion includes the following steps:

[0012] Step (1) The acrylic acid and its related ester monomers, the styrene monomers, water, and part of the emulsifier are mixed and pre-emulsified to obtain a pre-emulsified monomer;

[0013] Step (2) Water and the initiator are mixed to obtain initiator addition liquid A; the remaining emulsifier and water are mixed to obtain bottom liquid B;

[0014] Step (3) Take 4-6 wt% of pre-emulsified monomer and mix it with bottom liquid B, then add part of initiator addition liquid A to carry out the initial reaction. During the initial reaction, add functional monomer to pre-emulsified monomer. After the initial reaction is completed, add the remaining pre-emulsified monomer and part of the initiator addition liquid A at the same time. After heat preservation reaction, material C is obtained.

[0015] In step (4), the remaining initiator is added dropwise to material C to dissolve it in liquid A. After the reaction is kept at a constant temperature, the pH of the system is adjusted to 7-9.

[0016] In some embodiments, the initiator may include at least one of ammonium persulfate, potassium persulfate, and sodium persulfate.

[0017] In some embodiments, the acrylic acid and its related ester monomers are preferably in the form of 18-30 parts by weight.

[0018] In some embodiments, the styrene monomer is preferably present in 10-15 parts by weight.

[0019] In some embodiments, the emulsifier is preferably present in 2-4 parts by weight.

[0020] In some embodiments, the initiator is preferably present in a weight fraction of 0.4-0.6 parts.

[0021] In some embodiments, the functional monomer is preferably expressed in 2-3 parts by weight.

[0022] In some embodiments, the water is preferably in the form of 54-57 parts by weight.

[0023] In some embodiments, the weight ratio of the ammonium persulfate in the first part, the ammonium persulfate in the second part, and the ammonium persulfate in the third part may be 1:(1.2-1.5):(0.1-0.4).

[0024] In some embodiments, the mass ratio of a portion of the emulsifier to the remaining portion of the emulsifier may be 1:1.5.

[0025] In step (1), the pre-emulsification conditions and methods can be conventional in the art and can generally be carried out under stirring conditions.

[0026] In step (2), when preparing material A, the temperature of the mixing reaction can be the temperature conventional for this type of operation in the art, preferably 18-25℃.

[0027] In step (2), when preparing material A, the mixing reaction time can be the conventional time for this type of operation in the art, preferably 15-20 min.

[0028] In step (2), when preparing material B, the mixing temperature can be 85-87℃.

[0029] In step (3), the initial reaction time is 8-12 min.

[0030] In step (3), the portion of seed pre-emulsified monomer taken is preferably 4-6 wt%.

[0031] In step (3), the dripping time can be the conventional time for this type of operation in the art, preferably 3.5-5.5h.

[0032] In step (3), the temperature of the droplet is 82-87°C, more preferably 84-87°C.

[0033] In step (3), the pre-emulsified monomer and the over-initiator in the second part can be added simultaneously in accordance with the conventional practice in the art, and the addition can be stopped simultaneously.

[0034] In step (3), the temperature of the heat preservation reaction can be the temperature conventional for this type of operation in the art, preferably 84-87°C.

[0035] In step (3), the time for the heat preservation reaction can be the conventional time for this type of operation in the art, preferably 1-2.5h, more preferably 1.5-2h.

[0036] In step (4), the dripping time can be the conventional time for this type of operation in the art, preferably 20-40 min.

[0037] In step (4), the temperature at which the drop is added can be the temperature conventional for this type of operation in the art, preferably 85-87°C.

[0038] In step (4), the temperature of the heat preservation reaction can be the temperature conventional for this type of operation in the art, preferably 84-87°C.

[0039] In step (4), the time for the heat preservation reaction can be the conventional time for this type of operation in the art, preferably 1-1.5h.

[0040] In step (4), the second heat preservation reaction may be followed by a cooling operation, which can generally be reduced to below 40°C, preferably to 15-40°C.

[0041] The reagents and raw materials used in this invention are all commercially available.

[0042] The positive and progressive effects of this invention are as follows:

[0043] In addition to soft and hard monomers, the emulsion of this invention contains styrene monomers and vinyl silane functional monomers. The addition of styrene monomers helps to improve the hardness and strength of the emulsion, while the vinyl groups introduced in the vinyl silane functional monomers can undergo coupling reactions with polar groups such as hydroxyl and carboxyl groups in acrylic acid molecules to form strong covalent bonds, thereby improving water resistance and mechanical stability. Even when subjected to high shear forces, it can still maintain a certain stable structure of latex particles and is not easily dispersed and deactivated.

[0044] In emulsion preparation, the timing of adding vinyl silane functional monomers significantly impacts emulsion properties. This invention involves adding a pre-emulsified monomer containing the functional monomer after the initial reaction, followed by polymerization. A small portion of the pre-emulsified monomer undergoes preliminary polymerization (i.e., seed emulsion polymerization) in the emulsifier via an initiator, forming a sufficiently large number of sufficiently small latex particles in the micelles. Then, the functional monomer and other monomeric raw materials are introduced to continue polymerization, causing the polymer particles to gradually grow and form a uniform polymer dispersion. This method allows for sufficient coupling reactions between the vinyl silane functional monomers and the polar groups such as hydroxyl and carboxyl groups in the acrylic acid molecule. The vinyl functional groups are effectively grafted onto the long polymer chain, resulting in a stable reaction, moderate particle size, and improved water resistance and mechanical stability.

[0045] The water-based imitation stone emulsion prepared by this invention has an easy-to-control preparation process, a stable synthesis reaction, a moderate apparent particle size, and a low slag output. This synthesis process enhances the mechanical stability of the water-based imitation stone emulsion in the later stages. Attached Figure Description

[0046] Figure 1 shows the finished paint prepared by the water-based imitation stone emulsion synthesis method. Under environmental conditions of (23±1℃, humidity 50±2%), the disperser was turned on at 3500 rpm and dispersed at high speed until it was deactivated (the paint showed wavy patterns). Detailed Implementation

[0047] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0048] Example 1

[0049] In this embodiment, an aqueous imitation stone emulsion was prepared. The raw materials include the following components in parts by weight, as shown in Table 1.

[0050] Table 1. Weight proportions of each component in the raw materials

[0051]

[0052]

[0053] The preparation method of water-based stone-like emulsion includes the following steps:

[0054] (1) 40wt% sodium dodecyl sulfonate, 30wt% water, isooctyl acrylate, styrene, methyl methacrylate, methacrylic acid, and acrylamide were stirred and emulsified to obtain a pre-emulsified monomer.

[0055] (2) Add 50wt% water and the remaining sodium dodecyl sulfonate into the reactor, stir, and then heat to 86℃;

[0056] (3) Mix the remaining water with ammonium persulfate to obtain the initiator addition solution; add 4 wt% of the pre-emulsified monomer into the reactor, and immediately add 36 wt% of ammonium persulfate. The initial reaction lasts for 9 minutes. During the initial reaction, the functional monomer is poured into the remaining pre-emulsified monomer. After the initial reaction is completed, the remaining pre-emulsified monomer and 53 wt% of ammonium persulfate are added dropwise until the end. The temperature of the system during the dropwise addition is 86-87℃, and the dropwise addition time is 4h. After the dropwise addition is completed, the system is kept warm for 2h for the first time.

[0057] (4) Add the remaining 11wt% ammonium persulfate to eliminate residual monomers. The addition time is 30 min, and a second heat preservation reaction is carried out for 90 min. After the reaction is completed, the system temperature is lowered to below 40℃ and neutralized with ammonia water to a pH value of 7-9 to obtain water-based imitation stone emulsion.

[0058] Example 2

[0059] The raw materials in this embodiment include the following components in parts by weight, as detailed in Table 2.

[0060] Table 2. Weight proportions of each component in the raw materials

[0061] Components (by weight): Isooctyl acrylate 16 parts, Methyl methacrylate 9 parts, Styrene 14 parts, Methacrylic acid 1.5 parts, Acrylamide 0.5 parts, Sodium dodecyl sulfonate 3 parts, Ammonium persulfate 0.5 parts, Vinyltriacetoxysilane 2.5 parts, Water 53 parts surface

[0062] The preparation method of water-based stone-like emulsion includes the following steps:

[0063] (1) 40wt% sodium dodecyl sulfonate, 38wt% water, isooctyl acrylate, styrene, methyl methacrylate, methacrylic acid, and acrylamide were stirred and emulsified to obtain a pre-emulsified monomer.

[0064] (2) Add 50wt% water and the remaining sodium dodecyl sulfonate into the reactor, stir, and then heat to 86℃;

[0065] (3) Mix the remaining water with ammonium persulfate to obtain the initiator addition solution; add 5 wt% of the pre-emulsified monomer into the reactor, and immediately add 36 wt% of ammonium persulfate. The initial reaction lasts for 10 minutes. During the initial reaction, the functional monomer is poured into the remaining pre-emulsified monomer. After the initial reaction is completed, the remaining pre-emulsified monomer vinyltriacetoxysilane and 53 wt% of ammonium persulfate are added dropwise until the end. The temperature of the system during the dropwise addition is 86-87℃, and the dropwise addition time is 4h. After the dropwise addition is completed, the system is kept warm for 2h for the first time.

[0066] (4) Add the remaining 11wt% ammonium persulfate to eliminate residual monomers. The addition time is 30 min, and a second heat preservation reaction is carried out for 90 min. After the reaction is completed, the system temperature is lowered to below 40℃ and neutralized with ammonia water to a pH value of 7-9 to obtain water-based imitation stone emulsion.

[0067] Example 3

[0068] The raw materials in this embodiment include the following components in parts by weight, as detailed in Table 3.

[0069] Table 3. Weight proportions of each component in the raw materials

[0070] Components (by weight): Isooctyl acrylate 9 parts, n-butyl acrylate 7 parts, methyl methacrylate 9 parts, styrene 12 parts, methacrylic acid 1.5 parts, acrylic acid 1.5 parts, sodium dodecyl sulfonate 3 parts, ammonium persulfate 0.5 parts, vinyltriethoxysilane 2.5 parts, water 54 parts surface

[0071] The preparation method of water-based stone-like emulsion includes the following steps:

[0072] (1) 40wt% sodium dodecyl sulfonate, 35wt% water, isooctyl acrylate, n-butyl acrylate, styrene, methyl methacrylate, methacrylic acid, and acrylic acid were stirred and emulsified to obtain a pre-emulsified monomer.

[0073] (2) Add 50wt% water and the remaining sodium dodecyl sulfonate into the reactor, stir, and then heat to 86℃;

[0074] (3) Mix the remaining water with ammonium persulfate to obtain the initiator addition solution; add 4 wt% of the pre-emulsified monomer into the reactor, and immediately add 35 wt% of ammonium persulfate. The initial reaction takes 8 minutes. During the initial reaction, the functional monomer is poured into the remaining pre-emulsified monomer. After the initial reaction is completed, the remaining pre-emulsified monomer vinyltriethoxysilane and 53 wt% of ammonium persulfate are added dropwise until the end. The temperature of the system during the dropwise addition is 86-87℃, and the dropwise addition time is 4h. After the dropwise addition is completed, the system is kept warm for 2h for the first time.

[0075] (4) Add the remaining 12wt% ammonium persulfate to eliminate residual monomers. The addition time is 30 min, and a second heat preservation reaction is carried out for 90 min. After the reaction is completed, the system temperature is reduced to below 40℃ and neutralized with ammonia water to a pH value of 7-9 to obtain water-based imitation stone emulsion.

[0076] Example 4

[0077] The raw materials in this embodiment include the following components in parts by weight, as detailed in Table 4.

[0078] Table 4. Weight proportions of each component in the raw materials

[0079] Components (by weight): Isooctyl acrylate 14 parts, Methyl methacrylate 8 parts, 3-chlorostyrene 10 parts, Methacrylic acid 1.3 parts, Acrylic acid 1.7 parts, Tridecyl polyoxyethylene ether phosphate 3 parts, Ammonium persulfate 0.5 parts, Vinyltriethoxysilane 2.5 parts, Water 59 parts surface

[0080] The preparation method of water-based stone-like emulsion includes the following steps:

[0081] (1) 40wt% tridecyl polyoxyethylene ether phosphate, 33wt% water, isooctyl acrylate, 3-chlorostyrene, methyl methacrylate, methacrylic acid, and acrylic acid were stirred and emulsified to obtain a pre-emulsified monomer;

[0082] (2) 50wt% water and the remaining tridecyl polyoxyethylene ether phosphate were loaded into the reactor, stirred, and then heated to 86℃.

[0083] (3) Mix the remaining water with ammonium persulfate to obtain the initiator addition solution; add 5 wt% of the pre-emulsified monomer into the reactor, and immediately add 35 wt% of ammonium persulfate. The initial reaction takes 12 minutes. During the initial reaction, the functional monomer is poured into the remaining pre-emulsified monomer. After the initial reaction is completed, the remaining pre-emulsified monomer vinyltriethoxysilane and 53 wt% of ammonium persulfate are added dropwise until the end. The temperature of the system during the dropwise addition is 86-87℃, and the dropwise addition time is 4h. After the dropwise addition is completed, the system is kept warm for 2h for the first time.

[0084] (4) Add the remaining 12wt% ammonium persulfate to eliminate residual monomers. The addition time is 30 min, and a second heat preservation reaction is carried out for 90 min. After the reaction is completed, the system temperature is reduced to below 40℃ and neutralized with ammonia water to a pH value of 7-9 to obtain water-based imitation stone emulsion.

[0085] Referring to Example 1, the present invention also provides the following comparative examples.

[0086] Comparative Example 1

[0087] The specific raw material composition is the same as in Example 1, except that the timing of adding the functional monomers is different from that in Example 1.

[0088] The preparation method of water-based stone-like emulsion includes the following steps:

[0089] (1) 40wt% sodium dodecyl sulfonate, 30wt% water, isooctyl acrylate, styrene, methyl methacrylate, methacrylic acid, acrylamide and all functional monomers are stirred and emulsified to obtain a pre-emulsified monomer.

[0090] (2) Add 50wt% water and the remaining sodium dodecyl sulfonate into the reactor, stir, and then heat to 86℃;

[0091] (3) Take 4 wt% of the pre-emulsified monomer and add it into the reactor. Immediately add 36 wt% of ammonium persulfate. After the initial reaction is 9 minutes, start to add the remaining pre-emulsified monomer and 53 wt% of ammonium persulfate dropwise until the end. The temperature of the system during the drop is 86-87℃ and the drop time is 4 hours. After the drop is completed, keep the system warm for 2 hours.

[0092] (4) Add the remaining 11wt% ammonium persulfate to eliminate residual monomers. The addition time is 30 min, and a second heat preservation reaction is carried out for 90 min. After the reaction is completed, the system temperature is lowered to below 40℃ and neutralized with ammonia water to a pH value of 7-9 to obtain water-based imitation stone emulsion.

[0093] Comparative Example 2

[0094] The specific raw material composition is the same as in Example 1, except that the timing of adding the functional monomers is different from that in Example 1.

[0095] The preparation method of water-based stone-like emulsion includes the following steps:

[0096] (1) 40wt% sodium dodecyl sulfonate, 30wt% water, isooctyl acrylate, styrene, methyl methacrylate, methacrylic acid, and acrylamide were stirred and emulsified to obtain a pre-emulsified monomer.

[0097] (2) Add 50wt% water and the remaining sodium dodecyl sulfonate into the reactor, stir, and then heat to 86℃;

[0098] (3) Take 4 wt% of the pre-emulsified monomer and add it into the reactor. Immediately add 36 wt% of ammonium persulfate. After the initial reaction is 9 minutes, start to drop the remaining pre-emulsified monomer and 53 wt% of ammonium persulfate simultaneously until the end. The temperature of the system during the drop is 86-87℃ and the drop time is 4 hours. When the drop is 160 minutes, add the functional monomer to the remaining emulsified monomer and continue to drop until the drop is completed. After the drop is completed, keep the temperature for 2 hours for the first time.

[0099] (4) Add the remaining 11wt% ammonium persulfate to eliminate residual monomers. The addition time is 30 min, and a second heat preservation reaction is carried out for 90 min. After the reaction is completed, the system temperature is lowered to below 40℃ and neutralized with ammonia water to a pH value of 7-9 to obtain water-based imitation stone emulsion.

[0100] Comparative Example 3

[0101] The specific raw material composition is the same as in Example 1, except that the timing of the addition of the functional monomer is different from that in Example 1, and no initial reaction is carried out.

[0102] The preparation method of water-based stone-like emulsion includes the following steps:

[0103] (1) 40wt% sodium dodecyl sulfonate, 30wt% water, isooctyl acrylate, styrene, methyl methacrylate, methacrylic acid, acrylamide, and all functional monomers are stirred and emulsified to obtain a pre-emulsified monomer.

[0104] (2) Add 50wt% water and the remaining sodium dodecyl sulfonate into the reactor, stir, and then heat to 86℃;

[0105] (3) Add 36wt% ammonium persulfate, stir for 2 min, and simultaneously add the prepared pre-emulsified monomer and 53wt% ammonium persulfate until the end. The temperature of the system during the addition is 86-87℃, and the addition time is 4 h. Continue adding until the addition is complete, and then keep warm for 2 h for the first reaction.

[0106] (4) Add the remaining 11wt% ammonium persulfate to eliminate residual monomers. The addition time is 30 min, and a second heat preservation reaction is carried out for 90 min. After the reaction is completed, the system temperature is lowered to below 40℃ and neutralized with ammonia water to a pH value of 7-9 to obtain water-based imitation stone emulsion.

[0107] Comparative Example 4

[0108] The difference compared to Example 1 is that the functional monomer vinyltrimethoxysilane is not added.

[0109] Comparative Example 5

[0110] The difference from Example 1 is that the functional monomer vinyltrimethoxysilane is replaced with trimethoxysilane.

[0111] Comparative Example 6

[0112] The difference from Example 1 is that styrene is replaced with the hard monomer acrylonitrile.

[0113] Effect test

[0114] Using water-based stone-like emulsions or commercially available emulsions prepared in Examples 1-4 and Comparative Examples 1-6 as raw materials, coatings were prepared, and the mechanical stability of the finished paints was tested. The specific preparation method of the test materials was as follows: 115g of water, 15g of functional additives, 750g of sand powder, and 120g of water-based stone-like emulsion were stirred and dispersed evenly to prepare the coating. Under environmental conditions of (23±1℃, humidity 50±2%), the coating was placed under a high-speed dispersion disc, and the stirring was turned on at 3500 rpm until the coating reached a deactivated state (as shown in Figure 1). The time taken was recorded, and the holding time is shown in Table 5 below.

[0115] Table 5 Dispersed Schedule

[0116] Numbering and Dispersed Time: Example 1: 50 minutes; Example 2: 54 minutes; Example 3: 55 minutes; Example 4: 49 minutes; Comparative Example 1: 140 minutes; Comparative Example 2: 35 minutes; Comparative Example 3: 25 minutes; Comparative Example 4: 15 minutes; Comparative Example 5: 20 minutes; Comparative Example 6: 35 minutes surface

[0117] The test results show that the mechanical stability of the water-based imitation stone emulsions prepared in Examples 1-4 of this invention is significantly better than that of the water-based imitation stone emulsions prepared in Comparative Examples 1-6.

[0118] Although this disclosure has been described above through specific embodiments, it should be understood that those skilled in the art can devise various modifications, improvements, or equivalents to this disclosure within the spirit and scope of the appended solutions. Such modifications, improvements, or equivalents should also be considered to be included within the scope of protection claimed in this disclosure.

Claims

1. A method for preparing an aqueous imitation stone emulsion, characterized in that, The steps are as follows: Step (1) Acrylic acid and its related ester monomers, styrene monomers, water, and part of the emulsifier are mixed and pre-emulsified to obtain a pre-emulsified monomer; the acrylic acid and its related ester monomers are 18-30 parts by weight, and the acrylic acid and its ester monomers are composed of hard monomers and soft monomers, wherein the hard monomer is at least one of acrylic acid, acrylamide, methacrylic acid, and methyl methacrylate; the soft monomer is at least one of isooctyl acrylate, n-butyl acrylate, isobutyl acrylate, and ethyl acrylate; the weight ratio of the hard monomer to the soft monomer is 0.8-1:1; the styrene monomer is at least one of styrene and 3-chlorostyrene; the styrene monomer is 10 parts by weight. -15 parts; Step (2) mix water and initiator to obtain initiator addition liquid A; mix the remaining emulsifier and water to obtain bottom liquid B; the weight of water in steps (1) and (2) is 54-57 parts; the weight of emulsifier in steps (1) and (2) is 2-4 parts; the ratio of emulsifier added in steps (1) and (2) is 1:1.5; the emulsifier is sodium dodecyl sulfonate; the weight of initiator is 0.4-0.6 parts, and the initiator is ammonium persulfate; Step (3) take 4-6 wt% of pre-emulsified monomer and mix it with bottom liquid B, then add part of initiator addition liquid A to carry out the initial reaction, during the initial reaction, the function The monomer is added to the pre-emulsified monomer. After the initial reaction is completed, the remaining pre-emulsified monomer and part of the initiator addition solution A are added dropwise. After the reaction is kept at a certain temperature, material C is obtained. The functional monomer is vinyltriacetoxysilane or vinyltriethoxysilane, and the weight part of the functional monomer is 2-3 parts. In step (4), the remaining initiator addition solution A is added dropwise to material C. After the reaction is kept at a certain temperature, the pH value of the system is adjusted to 7-9. The weight ratio of the initiator addition solution in the first part, the second part and the third part is 1:(1.2-1.5):(0.1-0.4). When preparing material A, the temperature of the mixing reaction is 18-25℃. The mixing reaction time is 15-20 min, and the mixing temperature during the preparation of material B can be 85-87℃; in step (3), the initial reaction time is 8-12 min, the dropping time is 3.5-5.5 h, the dropping temperature is 84-87℃, the holding temperature is 84-87℃, and the holding time is 1.5-2 h; in step (4), the dropping time is 20-40 min, the dropping temperature is 85-87℃, the holding temperature is 84-87℃, and the holding time is 1-1.5 h, and the second holding reaction operation may further include a cooling operation, which is to cool down to 15-40℃.

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