A water-resistant waterborne acrylic adhesive and a preparation method thereof

Abstract

The application belongs to the technical field of adhesives, and discloses a water-based acrylic adhesive with water permeation resistance and a preparation method thereof. The raw material components of the water-based acrylic adhesive provided by the application include a reactive emulsifier, a comonomer, an initiator, a leveling agent, acicular wollastonite powder and water. The comonomer includes butyl acrylate, hydroxyethyl acrylate, monomer A and monomer B. The monomer A includes at least one of 2-hydroxyhexyl acrylate, methyl methacrylate and methyl acrylate. The monomer B includes acrylic acid and / or methacrylic acid. The adhesive provided by the application has excellent water permeation resistance and bonding performance through the joint action of the raw material components, and uses water as a solvent, so the adhesive is environmentally friendly.

Description

Technical Field

[0001] This invention belongs to the field of adhesive technology, and specifically relates to a water-resistant waterborne acrylic adhesive and its preparation method. Background Technology

[0002] Acrylic adhesives have a wide range of applications, including packaging, construction, labeling, and film lamination. However, traditional solvent-based acrylic adhesives use organic solvents as dispersion media, containing large amounts of volatile organic compounds (VOCs), which are toxic, harmful, and have a strong odor, causing environmental pollution and impacting human health. With increasingly stringent environmental policies, solvent-based acrylic adhesives are gradually being restricted. In contrast, water-based acrylic adhesives, using water as a dispersion medium, are non-toxic, non-polluting, and do not pose a threat to human health, and their properties are widely recognized.

[0003] Currently, most water-based acrylic adhesives have poor water penetration resistance and are prone to whitening upon contact with water, leading to decreased or even loss of adhesion. This limits their application in humid or water-contact environments. Therefore, there is a need to develop a water-based acrylic adhesive that improves both water penetration resistance and bonding performance. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. Therefore, the object of the present invention is to provide a water-resistant water-based acrylic adhesive and its preparation method. The water-based acrylic adhesive of the present invention has excellent water-resistant and adhesive properties, and uses water as a solvent, thus exhibiting good environmental friendliness.

[0005] In a first aspect, the present invention provides a water-based acrylic adhesive, wherein the raw material components of the water-based acrylic adhesive include: a reactive emulsifier, a comonomer, an initiator, a leveling agent, needle-like wollastonite powder, and water; the comonomer includes butyl acrylate, hydroxyethyl acrylate, monomer A, and monomer B; monomer A includes at least one of 2-hydroxyhexyl acrylate, methyl methacrylate, and methyl acrylate; and monomer B includes acrylic acid and / or methacrylic acid.

[0006] In some embodiments of the present invention, the raw material components of the water-based acrylic adhesive, by weight, include: 15-25 parts of reactive emulsifier, 350-500 parts of butyl acrylate, 0-45 parts of 2-hydroxyhexyl acrylate, 0-20 parts of methyl methacrylate, 0-30 parts of methyl acrylate, 0-18 parts of acrylic acid, 0-18 parts of methacrylic acid, 10-20 parts of hydroxyethyl acrylate, 0.5-2 parts of initiator, 0.5-4 parts of leveling agent, 5-15 parts of needle-like wollastonite powder, and 300-500 parts of water; the amounts of 2-hydroxyhexyl acrylate, methyl methacrylate, and methyl acrylate are all 0 parts; the amounts of acrylic acid and methacrylic acid are all 0 parts.

[0007] In some embodiments of the present invention, the raw material components of the water-based acrylic adhesive, by weight, include: 20 parts of reactive emulsifier, 400-445 parts of butyl acrylate, 25-30 parts of methyl acrylate, 13-18 parts of acrylic acid, 12-17 parts of hydroxyethyl acrylate, 0.5-2 parts of initiator, 0.5-4 parts of leveling agent, 5-15 parts of needle-like wollastonite powder, and 300-500 parts of water.

[0008] In some embodiments of the present invention, the raw material components of the water-based acrylic adhesive, by weight, include: 20 parts of reactive emulsifier, 400-445 parts of butyl acrylate, 40-45 parts of 2-hydroxyhexyl acrylate, 25-30 parts of methyl acrylate, 13-18 parts of acrylic acid, 12-17 parts of hydroxyethyl acrylate, 0.5-2 parts of initiator, 0.5-4 parts of leveling agent, 5-15 parts of needle-like wollastonite powder, and 300-500 parts of water.

[0009] In some embodiments of the present invention, the raw material components of the water-based acrylic adhesive, by weight, include: 20 parts of reactive emulsifier, 400-445 parts of butyl acrylate, 5-20 parts of methyl methacrylate, 13-18 parts of acrylic acid, 12-17 parts of hydroxyethyl acrylate, 0.5-2 parts of initiator, 0.5-4 parts of leveling agent, 5-15 parts of needle-like wollastonite powder, and 300-500 parts of water.

[0010] In some embodiments of the present invention, the raw material components of the water-based acrylic adhesive, by weight, include: 20 parts of reactive emulsifier, 400-445 parts of butyl acrylate, 5-20 parts of methyl methacrylate, 25-30 parts of methyl acrylate, 13-18 parts of acrylic acid, 12-17 parts of hydroxyethyl acrylate, 0.5-2 parts of initiator, 0.5-4 parts of leveling agent, 5-15 parts of needle-like wollastonite powder, and 300-500 parts of water.

[0011] In some embodiments of the present invention, the raw material components of the water-based acrylic adhesive, by weight, include: 20 parts of reactive emulsifier, 400-445 parts of butyl acrylate, 25-30 parts of methyl acrylate, 10-15 parts of methacrylic acid, 12-17 parts of hydroxyethyl acrylate, 0.5-2 parts of initiator, 0.5-4 parts of leveling agent, 5-15 parts of needle-like wollastonite powder, and 300-500 parts of water.

[0012] In some embodiments of the present invention, the reactive emulsifier includes at least one of NRS-10, SVS, and PVSA.

[0013] In some embodiments of the present invention, the initiator includes at least one of sodium persulfate, ammonium persulfate, and potassium persulfate.

[0014] In some embodiments of the present invention, the leveling agent includes at least one of DOWFAX 2A1, Aerosol 18P, and DISPONIL FES 77.

[0015] In some embodiments of the present invention, the raw material components of the water-based acrylic adhesive further include defoamers and / or pH adjusters.

[0016] In some embodiments of the present invention, the defoamer includes at least one of Tegopren 5885, Hydropalat WE3229, and DF01.

[0017] In some embodiments of the present invention, the pH adjuster includes ammonia.

[0018] A second aspect of the present invention provides a method for preparing the water-based acrylic adhesive described in the first aspect of the present invention, comprising the following steps: S1. Mix the reactive emulsifier, comonomer and water to obtain an emulsion; S2. Mix part of the leveling agent, part of the initiator and water, and heat to obtain the base liquid; S3. Mix a portion of the emulsion and the base liquid, react until blue light appears, and then add the remaining emulsion and the remaining initiator. S4. After the dripping is complete, add needle-shaped wollastonite powder, keep warm and stir. S5. Cool down, adjust pH, and then add the remaining leveling agent to obtain the water-based acrylic adhesive.

[0019] In some embodiments of the present invention, step S1 further includes a step of filtering using a 100-300 mesh filter.

[0020] In some embodiments of the present invention, in step S2, the heating temperature is 75-79°C.

[0021] In some embodiments of the present invention, in step S2, the partial leveling agent accounts for 45%-55% of the total leveling agent by mass, preferably 50%.

[0022] In some embodiments of the present invention, in step S2, the partial initiator accounts for 70%-80% of the total initiator by mass, preferably 75%.

[0023] In some embodiments of the present invention, the reaction temperature in step S3 is 75-85°C.

[0024] In some embodiments of the present invention, in step S3, the dripping time is 3-4.5 hours.

[0025] In some embodiments of the present invention, in step S3, the partial emulsion accounts for 0.5%-1.5% of the total emulsion by mass, preferably 0.6%-1.2%.

[0026] In some embodiments of the present invention, in step S4, the time for heat preservation and stirring is 1.5-2.5 hours.

[0027] In some embodiments of the present invention, in step S5, the cooling is to reduce the temperature to 45-60°C.

[0028] In some embodiments of the present invention, in step S5, adjusting the pH involves using ammonia to adjust the pH to 7.0-8.0.

[0029] In some embodiments of the present invention, step S5 further includes a step of filtering using a 100-300 mesh filter.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows: The water-based acrylic adhesive provided by this invention exhibits excellent water penetration resistance and adhesion properties through the synergistic effect of its various raw material components. Specifically, a reactive emulsifier is formed together with a comonomer to create a stable emulsion. The unsaturated double bonds of the reactive emulsifier open during the high-temperature reaction and react with the comonomer, stabilizing it within the polymer chain to enhance water penetration resistance and prevent excessive emulsifier molecules from migrating to the surface and causing performance degradation. Furthermore, a portion of the leveling agent is mixed with water to reduce the surface tension of the water and eliminate the surface tension gradient, thereby minimizing pinholes. Simultaneously, the amounts of emulsifier and initiator are controlled to form an emulsion with a small particle size (≤2µm) and a glossy finish. This water-based acrylic adhesive exhibits good color (blue hue), high transparency (transmittance ≥98.5% after drying), and uniform distribution. Utilizing the chemical cross-linking phenomenon that occurs during the copolymerization of acrylic acid and / or methacrylic acid with hydroxyethyl acrylate, the fine adhesive molecules are more tightly cross-linked, effectively preventing water molecule penetration and enhancing water permeability resistance. It also converts the intermolecular forces between chains into chemical bonds, thereby reducing creep and improving adhesion. Furthermore, the needle-like wollastonite powder encapsulated in the adhesive forms an inorganic-organic composite film, reducing surface wettability and providing excellent hydrophobic effects, further enhancing water permeability resistance. Detailed Implementation

[0031] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the raw materials, reagents, or apparatus used in the embodiments can be obtained from conventional commercial sources or by existing technical methods. Unless otherwise specified, the experimental or testing methods are conventional methods in the art.

[0032] The needle-shaped wollastonite powder used in the embodiments of the present invention can be purchased from Jiangxi Kete Fine Powder Co., Ltd.

[0033] Example 1 A water-based acrylic adhesive, the raw material components of which include: reactive emulsifier (NRS-10), butyl acrylate, methyl acrylate, acrylic acid, hydroxyethyl acrylate, ammonium persulfate, leveling agent (DOWFAX 2A1), defoamer (Tegopren5885), ammonia, needle-like wollastonite powder, and water.

[0034] The preparation method of the above-mentioned water-based acrylic adhesive is as follows: S1: Add 120g of deionized water and 20g of reactive emulsifier to the emulsification tank, and stir for 10 minutes to allow the reactive emulsifier to produce rich and stable foam in the deionized water to obtain the base liquid.

[0035] S2: Add 445g butyl acrylate, 30g methyl acrylate, 13g acrylic acid, and 12g hydroxyethyl acrylate to the base liquid of step S1, stir continuously for 20 minutes, and filter through a 200-mesh filter to obtain the emulsion.

[0036] S3: Weigh 210g of deionized water in the reactor, heat the water bath to 78℃ and stabilize for 5 minutes, add 2g of leveling agent (pre-dissolved in 10g of deionized water) and 1.5g of ammonium persulfate (pre-dissolved in 10g of deionized water), and stir for 5 minutes.

[0037] S4: Take 5g of the emulsion from step 2 as the seed emulsion and add it to the reactor. After the emulsion in the reactor turns blue and a large amount of reflux occurs, stir for 5 minutes. Then start adding the remaining emulsion from step S2 and 0.5g of ammonium persulfate (pre-dissolved in 32g of deionized water). Control the temperature at 80℃ and add the emulsion over 4 hours, stirring constantly during the addition.

[0038] S5: Keep the temperature inside the reactor at 80℃, add 10g of needle-shaped wollastonite powder, and keep it warm while stirring for 2 hours.

[0039] S6: Lower the temperature to 45℃, add ammonia to adjust the pH to 7.3, then add 2g of leveling agent and 0.5g of defoamer, stir for 5 minutes, and filter through a 200-mesh filter to obtain water-based acrylic adhesive.

[0040] Example 2 A water-based acrylic adhesive, the raw material components of which include: reactive emulsifier (NRS-10), butyl acrylate, 2-hydroxyhexyl acrylate, methyl acrylate, acrylic acid, hydroxyethyl acrylate, ammonium persulfate, leveling agent (DOWFAX 2A1), defoamer (Tegopren 5885), ammonia, needle-like wollastonite powder, and water.

[0041] The preparation method of the above-mentioned water-based acrylic adhesive is as follows: S1: Add 120g of deionized water and 20g of reactive emulsifier to the emulsification tank, and stir for 10 minutes to allow the reactive emulsifier to produce rich and stable foam in the deionized water to obtain the base liquid.

[0042] S2: Add 400g butyl acrylate, 45g 2-hydroxyhexyl acrylate, 30g methyl acrylate, 13g acrylic acid, and 12g hydroxyethyl acrylate to the base liquid in step S1, stir continuously for 20 minutes, and filter through a 200-mesh filter to obtain the emulsion.

[0043] S3: Weigh 210g of deionized water in the reactor, heat the water bath to 78℃ and stabilize for 5 minutes, add 2g of leveling agent (pre-dissolved in 10g of deionized water) and 1.5g of ammonium persulfate (pre-dissolved in 10g of deionized water), and stir for 5 minutes.

[0044] S4: Take 7g of the emulsion from step 2 as the seed emulsion and add it to the reactor. After the emulsion in the reactor turns blue and a large amount of reflux occurs, stir for 5 minutes. Then start adding the remaining emulsion from step S2 and 0.5g of ammonium persulfate (pre-dissolved in 32g of deionized water). Control the temperature at 82℃ and add the emulsion over 4.5 hours, stirring constantly during the addition.

[0045] S5: Keep the temperature inside the reactor at 80℃, add 10g of needle-shaped wollastonite powder, and keep it warm while stirring for 2 hours.

[0046] S6: Lower the temperature to 45℃, add ammonia to adjust the pH to 7.6, then add 2g of leveling agent and 0.7g of defoamer, stir for 5 minutes, and filter through a 200-mesh filter to obtain water-based acrylic adhesive.

[0047] Example 3 A water-based acrylic adhesive, the raw material components of which include: reactive emulsifier (NRS-10), butyl acrylate, methyl methacrylate, acrylic acid, hydroxyethyl acrylate, ammonium persulfate, leveling agent (DOWFAX 2A1), defoamer (Tegopren 5885), ammonia, needle-like wollastonite powder, and water.

[0048] The preparation method of the above-mentioned water-based acrylic adhesive is as follows: S1: Add 120g of deionized water and 20g of reactive emulsifier to the emulsification tank, and stir for 10 minutes to allow the reactive emulsifier to produce rich and stable foam in the deionized water to obtain the base liquid.

[0049] S2: Add 445g butyl acrylate, 20g methyl methacrylate, 18g acrylic acid, and 17g hydroxyethyl acrylate to the base liquid of step S1, stir continuously for 20 minutes, and filter through a 300-mesh filter to obtain the emulsion.

[0050] S3: Weigh 210g of deionized water in the reactor, heat the water bath to 78℃ and stabilize for 5 minutes, add 2g of leveling agent (pre-dissolved in 10g of deionized water) and 1.5g of ammonium persulfate (pre-dissolved in 10g of deionized water), and stir for 5 minutes.

[0051] S4: Take 6g of the emulsion from step 2 as the seed emulsion and add it to the reactor. After the emulsion in the reactor turns blue and a large amount of reflux occurs, stir for 5 minutes. Then start adding the remaining emulsion from step S2 and 0.5g of ammonium persulfate (pre-dissolved in 32g of deionized water). Control the temperature at 80℃ and add the emulsion over 4 hours, stirring constantly during the addition.

[0052] S5: Keep the temperature inside the reactor at 80℃, add 10g of needle-shaped wollastonite powder, and keep it warm while stirring for 2 hours.

[0053] S6: Lower the temperature to 45℃, add ammonia to adjust the pH to 7.3, then add 2g of leveling agent and 0.5g of defoamer, stir for 5 minutes, and filter through a 300-mesh filter to obtain water-based acrylic adhesive.

[0054] Example 4 A water-based acrylic adhesive, the raw material components of which include: reactive emulsifier (NRS-10), butyl acrylate, methyl methacrylate, methyl acrylate, acrylic acid, hydroxyethyl acrylate, ammonium persulfate, leveling agent (DOWFAX 2A1), defoamer (Tegopren 5885), ammonia, needle-like wollastonite powder, and water.

[0055] The preparation method of the above-mentioned water-based acrylic adhesive is as follows: S1: Add 120g of deionized water and 20g of reactive emulsifier to the emulsification tank, and stir for 10 minutes to allow the reactive emulsifier to produce rich and stable foam in the deionized water to obtain the base liquid.

[0056] S2: Add 445g butyl acrylate, 5g methyl methacrylate, 25g methyl acrylate, 13g acrylic acid, and 12g hydroxyethyl acrylate to the base liquid in step S1, stir continuously for 20 minutes, and filter through a 200-mesh filter to obtain the emulsion.

[0057] S3: Weigh 210g of deionized water in the reactor, heat the water bath to 77℃ and stabilize for 5 minutes, add 2g of leveling agent (pre-dissolved in 10g of deionized water) and 1.5g of ammonium persulfate (pre-dissolved in 10g of deionized water), and stir for 5 minutes.

[0058] S4: Take 6g of the emulsion from step 2 as the seed emulsion and add it to the reactor. After the emulsion in the reactor turns blue and a large amount of reflux occurs, stir for 5 minutes. Then start adding the remaining emulsion from step S2 and 0.5g of ammonium persulfate (pre-dissolved in 32g of deionized water). Control the temperature at 82℃ and add the emulsion over 3.5 hours, stirring constantly during the addition.

[0059] S5: Keep the temperature inside the reactor at 80℃, add 10g of needle-shaped wollastonite powder, and keep it warm while stirring for 2 hours.

[0060] S6: Lower the temperature to 45℃, add ammonia to adjust the pH to 7.6, then add 2g of leveling agent and 0.5g of defoamer, stir for 5 minutes, and filter through a 200-mesh filter to obtain water-based acrylic adhesive.

[0061] Example 5 The only difference between this embodiment and Embodiment 1 is that ammonium persulfate is replaced with an equal amount of potassium persulfate, while the other raw material components, dosages, and preparation methods are the same as in Embodiment 1.

[0062] Example 6 The only difference between this embodiment and Example 1 is that acrylic acid is replaced with an equal amount of methacrylic acid, while the other raw material components, dosages, and preparation methods are the same as in Example 1.

[0063] Comparative Example 1 The only difference between this comparative example and Example 1 is that needle-shaped wollastonite powder is not added, while the other raw material components, dosages, and preparation methods are the same as in Example 1.

[0064] Comparative Example 2 The only difference between this comparative example and Example 1 is that the amount of ammonium persulfate in step S3 is adjusted to 3g and the amount of ammonium persulfate in step S4 is adjusted to 1g. The other raw material components, amounts, and preparation methods are the same as in Example 1.

[0065] Comparative Example 3 The only difference between this comparative example and Example 1 is that the amount of reactive emulsifier in step S1 is adjusted to 10g, while the other raw material components, amounts, and preparation methods are the same as in Example 1.

[0066] Comparative Example 4 The only difference between this comparative example and Example 1 is that the reactive emulsifier is replaced with an equal amount of maleic anhydride, while the other raw material components, dosages, and preparation methods are the same as in Example 1.

[0067] Comparative Example 5 The only difference between this comparative example and Example 1 is that no leveling agent is added in step S3 and the amount of leveling agent in step S6 is adjusted to 4g. The other raw material components, amounts, and preparation methods are the same as in Example 1.

[0068] Comparative Example 6 The only difference between this comparative example and Example 1 is that acrylic acid is not added in step S2 and the amount of hydroxyethyl acrylate is adjusted to 25g. The other raw material components, amounts, and preparation methods are the same as in Example 1.

[0069] Adhesive performance testing The testing instruments used were: electric thermostatic drying oven - Guangzhou Kangheng Instrument Co., Ltd.; computerized tape tensile testing machine - Dongguan Zhangmutou Aotong Instrument Equipment Factory; holding power tester - Dongguan Zhangmutou Instrument Equipment Co., Ltd.; and the inclined groove ball rolling device shown in 8.1 of GB / T 4852-2002.

[0070] Adhesion performance test: The water-based acrylic adhesives prepared in the examples and comparative examples were coated onto the surface of BOPP film using a wire rod. The electric heating constant temperature drying oven was adjusted to 102℃, and the coated samples were placed in the oven and dried for 10 minutes, with the dry adhesive thickness controlled at 15μm. Peel strength was tested according to standard GB / T 2792-2014; holding power was tested according to standard GB 4851-2014; viscosity was tested according to GB / T 2794-2022; and initial tack was tested according to standard GB / T 4852-2002 using the skew groove rolling ball method.

[0071] Water penetration resistance test: The water-based acrylic adhesive prepared in the examples and comparative examples was applied to a 24mm wide substrate surface to make tape, which was then attached to the surface of the stainless steel plate described in part 5.3.3 of GB / T 2792-2014. The tape was then rolled back and forth twice using a cylindrical steel roller as described in part 5.3.4.1 of GB / T 2792-2014 and the method described in part 5.3.4.2 of GB / T 2792-2014. The prepared sample was then immersed in water at 24±1℃ for 5, 7, and 9 days. The edges were then observed for whitening and peeling.

[0072] The test results are shown in Tables 1 and 2.

[0073] Table 1

[0074] Table 2

[0075] As shown in Tables 1 and 2, compared with the comparative examples, the water-based acrylic adhesive prepared in the embodiments of the present invention has excellent water penetration resistance. Furthermore, as can be seen from Table 1, in Example 2, reducing the amount of butyl acrylate and adding an equal amount of 2-hydroxyhexyl acrylate improves peel strength and initial tack, but slightly reduces holding power; in Example 3, replacing methyl acrylate with methyl methacrylate and reducing its amount while increasing the amounts of acrylic acid and hydroxyethyl acrylate improves holding power, but reduces peel strength; in Example 4, reducing the amount of methyl acrylate and increasing the amount of methyl methacrylate also improves holding power, but reduces peel strength; in Example 5, the use of potassium persulfate has little effect on performance; in Example 6, the use of methacrylic acid also results in a chemical cross-linking reaction with little effect on performance.

[0076] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A water-based acrylic adhesive, characterized in that, The raw material components of the water-based acrylic adhesive include: a reactive emulsifier, a comonomer, an initiator, a leveling agent, needle-like wollastonite powder, and water; the comonomer includes butyl acrylate, hydroxyethyl acrylate, monomer A, and monomer B; monomer A includes at least one of 2-hydroxyhexyl acrylate, methyl methacrylate, and methyl acrylate; monomer B includes acrylic acid and / or methacrylic acid.

2. The water-based acrylic adhesive according to claim 1, characterized in that, The raw material components of the water-based acrylic adhesive, by weight, include: 15-25 parts reactive emulsifier, 350-500 parts butyl acrylate, 0-45 parts 2-hydroxyhexyl acrylate, 0-20 parts methyl methacrylate, 0-30 parts methyl acrylate, 0-18 parts acrylic acid, 0-18 parts methacrylic acid, 10-20 parts hydroxyethyl acrylate, 0.5-2 parts initiator, 0.5-4 parts leveling agent, 5-15 parts needle-like wollastonite powder, and 300-500 parts water; the amounts of 2-hydroxyhexyl acrylate, methyl methacrylate, and methyl acrylate are all 0 parts; the amounts of acrylic acid and methacrylic acid are all 0 parts.

3. The water-based acrylic adhesive according to claim 1, characterized in that, The reactive emulsifier includes at least one of NRS-10, SVS, and PVSA.

4. The water-based acrylic adhesive according to claim 1, characterized in that, The initiator includes at least one of sodium persulfate, ammonium persulfate, and potassium persulfate.

5. The water-based acrylic adhesive according to claim 1, characterized in that, The leveling agent includes at least one of DOWFAX2A1, Aerosol 18P, and DISPONIL FES 77.

6. The water-based acrylic adhesive according to claim 1, characterized in that, The raw material components of the water-based acrylic adhesive also include defoamers and / or pH adjusters.

7. A method for preparing the water-based acrylic adhesive as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Mix the reactive emulsifier, comonomer and water to obtain an emulsion; S2. Mix part of the leveling agent, part of the initiator and water, and heat to obtain the base liquid; S3. Mix a portion of the emulsion and the base liquid, react until blue light appears, and then add the remaining emulsion and the remaining initiator. S4. After the dripping is complete, add needle-shaped wollastonite powder, keep warm and stir. S5. Cool down, adjust pH, and then add the remaining leveling agent to obtain the water-based acrylic adhesive.

8. The preparation method according to claim 7, characterized in that, In step S2, the heating temperature is 75-79℃.

9. The preparation method according to claim 7, characterized in that, In step S3, the reaction temperature is 75-85℃; and / or the dropping time is 3-4.5h.

10. The preparation method according to claim 7, characterized in that, In step S4, the time for heat preservation and stirring is 1.5-2.5 hours.

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