High-performance water-based automobile damping coating and preparation method thereof

Abstract

The invention relates to a water-based automobile damping coating and a preparation method thereof. The water-based automobile damping coating comprises functional filler phenol amine modified sodium carboxymethyl cellulose. Phenol amine in the phenol amine modified sodium carboxymethyl cellulose and groups in the acrylic emulsion form hydrogen bonds, so that a macromolecular chain segment and an emulsion base material are stronger in binding force and larger in stress, chain segment winding and powder distribution are more uniform and more integrated, and sagging and falling are prevented. The water-based automobile damping coating disclosed by the invention has the characteristics of relatively good construction performance, sagging resistance, swelling resistance, good formaldehyde removal effect, bacteriostasis and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and particularly relates to a high-performance automotive damping coating with good construction performance, anti-bulging, and formaldehyde removal properties, and a preparation method thereof. Background Art

[0002] With the gradual improvement of people's living standards, while people pursue fast and convenient travel, they also have higher and higher requirements for vehicles with low noise, environmental protection, and lightweight.

[0003] Waterborne damping coatings have been increasingly used in the fields of automobiles, rail transit, ships, etc. in recent years, and have the characteristics of easy construction, easy transportation, easy storage, green environmental protection, excellent performance, low density, and lightweight. The construction of automotive damping coatings requires high-temperature baking. During the baking process, the evaporation of water will cause the coating to bulge, blister, and deform, affecting subsequent use. Moreover, bacteria are likely to grow in the aqueous phase of waterborne coatings. A series of factors affect the wide application of waterborne damping coatings. In addition, in recent years, consumers "turn pale at the mention of formaldehyde" and have higher and higher requirements for the environmental protection and odor of passenger cars. The above are all the key technical points that need to be solved.

[0004] At present, formaldehyde removal technology has been applied to interior wall latex paints on the market. However, in order to improve the efficiency of formaldehyde removal for special interior wall latex paints for removing formaldehyde, the addition amounts of emulsions and formaldehyde removal functional materials are greatly increased, which not only increases the cost but also violates the concept and development trend of environmental protection. The commonly used formaldehyde removal coatings on the market are mainly divided into formaldehyde adsorption materials and formaldehyde decomposition materials. The problem with adsorption materials is that they will release formaldehyde again after adsorption; decomposition materials are generally divided into being added to the coating formula as additives or directly participating in emulsion polymerization as functional monomers. Adding external additives will increase the raw materials and operating costs of the coating, and the price of functional monomers is relatively high and the addition amount is limited.

[0005] Patent CN202011279080 discloses a bakeable damping coating, which realizes the anti-bulging effect of the coating during baking by adding auxiliary fillers including: water-absorbing resin, starch, and diatomite. However, in this method, if the fillers are unevenly distributed, it is easy to cause the situation of small blisters in some parts without obvious bulging. Patent CN202011279053 discloses using high-boiling solvents that can dissolve in water or emulsion to prevent bulging, such as one or a combination of ethylene glycol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol, DINP, and DOP. This method results in a strong odor during the construction process and is contrary to the trend of coating waterborne.

[0006] In addition, there has been no report on antibacterial damping coatings in the prior art. The antibacterial and bacteriostatic properties of other antibacterial coatings are provided by adding bactericides during the formulation preparation process or emulsion polymerization process. Summary of the Invention

[0007] To solve the problems existing in the prior art, the present invention provides a high-performance waterborne automotive damping coating with formaldehyde removal, anti-bulging, and excellent appearance.

[0008] Another object of the present invention is to provide a preparation method for this high-performance waterborne automotive damping coating.

[0009] To achieve the above invention objects, the present invention adopts the following technical solutions:

[0010] A high-performance waterborne automotive damping coating, comprising components in the following mass percentages:

[0011] Acrylic emulsion 25 - 45 wt%, such as 26 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%, 31 wt%, 32 wt%, 33 wt%, 34 wt%, 35 wt%, 36 wt%, 37 wt%, 38 wt%, 39 wt%, 40 wt%, 41 wt%, 42 wt%, 43 wt%, 44 wt%, 45 wt%, etc.;

[0012] Pigment and filler 20 - 40 wt%, such as 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, 26 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%, 31 wt%, 32 wt%, 33 wt%, 34 wt%, 35 wt%, 36 wt%, 37 wt%, 38 wt%, 39 wt%, 40 wt%, etc.;

[0013] Modified sodium carboxymethyl cellulose 2 - 10 wt%, such as 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, etc.;

[0014] Deionized water 13 - 25 wt%, such as 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, etc.;

[0015] Dispersant 0.5 - 2.0 wt%, such as 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, 2 wt%, etc.;

[0016] Thickener: 0.5 - 2.0 wt%, such as 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, 2 wt%, etc.;

[0017] Wetting agent: 0.2 - 1.0 wt%, such as 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, etc.;

[0018] Defoaming agent: 0.3 - 1.0 wt%, such as 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, etc.;

[0019] pH regulator: 0.1 - 1.0 wt%, such as 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, etc.

[0020] In a specific embodiment, the modified sodium carboxymethyl cellulose is phenolamine - modified sodium carboxymethyl cellulose. Preferably, it is prepared by the dehydration condensation reaction of sodium carboxymethyl cellulose and phenolamine.

[0021] In a specific embodiment, the phenolamine is selected from any one of o - aminophenol, p - aminophenol, and m - aminophenol, and preferably o - aminophenol.

[0022] In a specific embodiment, the preparation method of the phenolamine - modified sodium carboxymethyl cellulose comprises the following steps:

[0023] 1) Dissolve sodium carboxymethyl cellulose in water. First, add acid to adjust the pH value in the formed aqueous solution, add dicyclohexylcarbodiimide (EDC) and N - hydroxysuccinimide (NHS) to activate the carboxyl reaction, and then add phenolamine, and react at room temperature;

[0024] 2) Use frozen ether for precipitation, separate and dry to obtain phenolamine - modified sodium carboxymethyl cellulose.

[0025] Specifically, for example, the preparation method is as follows:

[0026] (1) Dissolve 40 - 50 wt% sodium carboxymethyl cellulose in water. First, add HCl to its solution to adjust the pH to 4.5 - 6.5. Then add 1 - 2 wt% dicyclohexylcarbodiimide and 3 - 5 wt% N-hydroxysuccinimide to activate the carboxyl group, and react for 30 - 60 min. After that, add 50 - 60 wt% phenolamine and react at room temperature for 2 - 5 hours.

[0027] (2) Use frozen ether for precipitation, separation, and drying to obtain phenolamine-modified sodium carboxymethyl cellulose.

[0028] Among them, based on the sum of the masses of sodium carboxymethyl cellulose and phenolamine, the addition amount of sodium carboxymethyl cellulose accounts for 40 - 50 wt%, and the addition amount of phenolamine accounts for 50 - 60 wt%. Similarly, based on the sum of the masses of sodium carboxymethyl cellulose and phenolamine, the addition amount of dicyclohexylcarbodiimide is 1 - 2 wt%, and the addition amount of N-hydroxysuccinimide is 3 - 5 wt%. In the present invention, the amount of water used has no special limitation, as long as it can fully dissolve sodium carboxymethyl cellulose, for example, water with a mass 2 - 5 times that of sodium carboxymethyl cellulose.

[0029] The reaction mechanism of this modification process is that EDC and NHS first activate the carboxyl group, and the carboxyl group reacts with the amino group of phenolamine to form an amide, which is a common carboxyl amidation process; the reaction process is shown in the following equation:

[0030]

[0031] In a specific embodiment, the aqueous acrylic emulsion in the present invention is one or several of Wanhua Chemical Antamp0652, Antamp 0655, Antamp0658, Antamp0656, Antamp0657, and preferably Antamp 0658.

[0032] In a specific embodiment, the pigments and fillers in the present invention include but are not limited to carbon black, talc powder, mica powder, calcium carbonate, etc.

[0033] Specifically, the carbon black in the functional pigments and fillers in the present invention includes but is not limited to FW-200 of Degussa (China) Co., Ltd., N300 of Hebei Cangzhou Jintai Carbon Black Co., Ltd., etc., and preferably FW-200.

[0034] The calcium carbonate in the pigments and fillers in the present invention includes but is not limited to one or several of 325-mesh heavy calcium carbonate, 400-mesh heavy calcium carbonate, 700-mesh heavy calcium carbonate, 800-mesh heavy calcium carbonate, etc. of Changzhou Calcium Carbonate Co., Ltd., and preferably 325-mesh heavy calcium carbonate and / or 400-mesh heavy calcium carbonate.

[0035] Among the pigments and fillers of the present invention, the mica powder includes but is not limited to at least any one of the 100-mesh mica powder of Chuzhou Sericite Co., Ltd., the 200-mesh mica powder of Shijiazhuang Chenxing Industry Co., Ltd., etc.

[0036] In a specific embodiment, the dispersant of the present invention includes but is not limited to at least any one of Orotan 731A of Dow (China) Co., Ltd., BYK 190 of BYK Chemie, C20 of Wanhua Chemical Group Co., Ltd., Tego 760w of Degussa, etc., and preferably any one of Tego 760w and Orotan 731A.

[0037] In a specific embodiment, the thickener of the present invention includes but is not limited to at least any one of Vesmody A801, Vesmody A401 of Wanhua Chemical Group Co., Ltd., ASE60 of Dow (China) Co., Ltd., etc., and preferably any one of Vesmody A801 and ASE60.

[0038] In a specific embodiment, the wetting agent of the present invention includes but is not limited to at least any one of Tego270, Tego280, Tego KL 245 of Degussa (China) Co., Ltd., Surfynol 104E of Air Products and Chemicals, Inc., etc., and preferably any one of Tego270 and KL 245.

[0039] In a specific embodiment, the defoamer of the present invention includes but is not limited to at least any one of Foam Star ST2410AC of BASF (China) Co., Ltd., BYK 810 of BYK Chemie, Foamex 1488 of Degussa (China) Co., Ltd., etc., and preferably any one of Foam Star ST2410AC and BYK 810.

[0040] In a specific embodiment, the pH regulator of the present invention includes but is not limited to at least any one of AMP-95, ammonia water, DMEA, etc., and preferably AMP-95.

[0041] On the other hand of the present invention, a high-performance waterborne automotive damping coating includes the following preparation steps:

[0042] (1) Mix the acrylic emulsion, dispersant, wetting agent, defoamer, and pH regulator, and disperse for 3-5 minutes to obtain an aqueous emulsion;

[0043] (2) Mix deionized water, modified sodium carboxymethyl cellulose, and pigments and fillers, and disperse for 5-10 minutes to obtain a mixture;

[0044] (3) Mix the mixture in step (2) with the aqueous emulsion in step (1), then add a thickener and disperse it. The disperser is operated at a rotational speed of 1000 - 1500 rpm for 10 - 15 minutes to obtain the aqueous automotive damping coating.

[0045] Compared with the prior art, the positive effects of the present invention are as follows:

[0046] The aqueous automotive damping coating of the present invention contains the functional filler phenolamine - modified sodium carboxymethyl cellulose. In the aqueous damping coating prepared by adding this filler, hydrogen bonds are formed between the phenolamine of the phenolamine - modified sodium carboxymethyl cellulose and the groups in the acrylic emulsion, making the binding force between the macromolecular chain segments and the emulsion base material stronger, the stress greater, and the chain segment entanglement and powder distribution more uniform and more integrated, preventing sagging and peeling. When baking and constructing at 140 - 160 °C, the strong overall stress prevents partial bulging or bubbling of the paint film. On the other hand, the good water - retaining property of sodium carboxymethyl cellulose makes the evaporation of water vapor slower and more uniform, preventing the sudden escape of water to lift the surface coating and cause bulging or bubbling; meanwhile, the presence of phenol groups in the modified sodium carboxymethyl cellulose can react with free formaldehyde in the vehicle to remove formaldehyde; during the storage of the coating, the protonation of the modified sodium carboxymethyl cellulose generates positive charges that act on the surface of bacteria, inhibiting bacterial reproduction and playing an antibacterial role, which can extend the storage shelf life of the coating.

[0047] The aqueous automotive damping coating of the present invention has good construction performance, anti - sagging and anti - bulging properties, good formaldehyde - removing effect, antibacterial properties, etc.

[0048] The method for preparing the damping coating of the present invention is more convenient and faster in construction than separately adding auxiliaries such as foaming microspheres, bactericides, and formaldehyde - removing agents to the damping coating formulation, and has better compatibility and can exist more stably in the system. Detailed implementation manners

[0049] To better understand the technical solution of the present invention, the following examples will further illustrate the method provided by the present invention. However, the present invention is not limited to the listed examples, and should also include any other well - known changes within the scope of the claims of the present invention.

[0050] The raw materials and their sources used in the detailed implementation manners are shown in the following table.

[0051] Table 1 Raw materials for preparing aqueous damping coating

[0052]

[0053]

[0054] The analysis and testing methods involved in the examples are as follows:

[0055] Test on formaldehyde removal efficiency of waterborne damping coating: Determination of purification performance of coating materials with indoor air purification function according to the standard JC / T 1074-2008 of the building materials industry.

[0056] Antibacterial test of waterborne damping coating: Test according to the standard HG / T 3950-2007, and the tested bacterial strains are Escherichia coli and Staphylococcus aureus.

[0057] Anti-bulging test of waterborne damping coating: Scraping the waterborne damping coating onto a carbon steel plate with a thickness of 3-4 mm, placing the coating film in an oven at 140 °C for 30 min, and observing the appearance of the coating film after taking it out.

[0058] The damping performance (loss factor) is measured by the cantilever beam method. The damping coating is applied to a steel plate of 10×220×0.8 (mm) to achieve a surface density (after drying) of 10×200×3.0, and placed in an oven at 140 °C for 30 minutes for baking and drying. After drying, the coated plate is used as a test plate for evaluation and inspected by the cantilever beam method, and the loss factor at the secondary resonance point is calculated by the half-width method.

[0059] Example 1

[0060] (1) Preparation of modified sodium carboxymethylcellulose:

[0061] (1.1) Dissolve 43 g of sodium carboxymethylcellulose in 100 g of water. First, add HCl to adjust the pH to 5.0 in the solution, add 1.5 g of dicyclohexylcarbodiimide and 4 g of N-hydroxysuccinimide to activate the carboxyl group, react for 50 min, then add 57 g of phenolamine, and react at room temperature for 3.5 hours;

[0062] (1.2) Precipitate with frozen ether, separate and dry to obtain phenolamine-modified sodium carboxymethylcellulose.

[0063] (2) Prepare the waterborne damping coating according to the formula in Table 2.

[0064] Table 2: Formula of waterborne damping coating

[0065] Name Mass / g Function ANTAMP 0658 35 Emulsion base material Deionized water 20 / 2410 0.6 Defoamer 731A 1.5 Dispersant AMP-95 0.5 pH regulator Tego 270 0.5 Wetting agent Modified sodium carboxymethyl cellulose 3 Filler Carbon black FW-200 1.0 Pigment 325-mesh heavy calcium carbonate 21.8 Filler 200-mesh mica powder 14.2 Filler A801 1.9 Thickener

[0066] Obtain waterborne damping coating 1 containing modified sodium cellulose, hereinafter referred to as coating 1.

[0067] Example 2

[0068] (1) Preparation of modified sodium carboxymethylcellulose:

[0069] (1.1) Dissolve 45 g of sodium carboxymethyl cellulose in 100 g of water. First, add HCl to adjust the pH to 6.0 in the solution. Then add 1.8 g of dicyclohexylcarbodiimide and 4.2 g of N-hydroxysuccinimide to activate the carboxyl group, and react for 40 min. Next, add 55 g of phenolamine and react at room temperature for 4 hours;

[0070] (1.2) Use frozen ether for precipitation, separation, and drying to obtain phenolamine-modified sodium carboxymethyl cellulose.

[0071] (2) Prepare the waterborne damping coating according to the formulation in Table 3.

[0072] Table 3: Formulation of waterborne damping coating

[0073]

[0074] Obtain waterborne damping coating 2 containing modified sodium cellulose, hereinafter referred to as coating 2.

[0075] Example 3

[0076] (1) Prepare modified sodium carboxymethyl cellulose:

[0077] (1.1) Dissolve 49 g of sodium carboxymethyl cellulose in 100 g of water. First, add HCl to adjust the pH to 5.5 in the solution. Then add 2 g of dicyclohexylcarbodiimide and 4.5 g of N-hydroxysuccinimide to activate the carboxyl group, and react for 60 min. Next, add 51 g of phenolamine and react at room temperature for 4.5 hours;

[0078] (1.2) Use frozen ether for precipitation, separation, and drying to obtain phenolamine-modified sodium carboxymethyl cellulose.

[0079] (2) Prepare the waterborne damping coating according to the formulation in Table 4.

[0080] Table 4: Formulation of waterborne damping coating

[0081] Name Mass / g Function ANTAMP 0656 27 Emulsion base material Deionized water 20 / 810 1.0 Defoamer 760w 1.0 Dispersant AMP-95 0.2 pH regulator Tego 270 0.6 Wetting agent Modified sodium carboxymethyl cellulose 10 Filler Carbon black FW-200 0.2 Pigment 325-mesh heavy calcium carbonate 26 Filler 200-mesh mica powder 13.3 Filler ASE60 0.7 Thickener

[0082] Obtain waterborne damping coating 3 containing modified sodium cellulose, hereinafter referred to as coating 3.

[0083] Comparative Example 1

[0084] Replace the phenolamine-modified sodium carboxymethyl cellulose in Example 3 with the same mass of sodium carboxymethyl cellulose to obtain waterborne damping coating 4, hereinafter referred to as coating 4.

[0085] The relevant properties of the waterborne damping coatings prepared in the examples and comparative examples are shown in Table 5.

[0086] Table 5 Performance table of waterborne damping coating

[0087]

[0088] As can be seen from the results in the above table, the waterborne automotive damping coating prepared using phenolamine-modified sodium carboxymethyl cellulose as a functional filler has good anti-bulging, antibacterial, and formaldehyde-removing effects. No obvious antibacterial, anti-bulging, and formaldehyde-removing effects were observed when conventional sodium carboxymethyl cellulose was used as a filler; moreover, this method has no negative impact on the damping factor and damping effect of the coating.

[0089] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as a limitation of the present invention. Those skilled in the art can understand that some modifications or adjustments can be made to the present invention under the teaching of this specification. These modifications or adjustments should also be within the scope defined by the claims of the present invention.

Claims

1. A high-performance water-based automotive damping coating, characterized in that: Contains the following components in percentage by mass:

2. The high performance water-based automotive damping coating according to claim 1, characterized in that: The modified sodium carboxymethyl cellulose is phenolamine-modified sodium carboxymethyl cellulose, and is preferably prepared from sodium carboxymethyl cellulose and phenolamine through a dehydration condensation reaction.

3. The high performance water-based automotive damping coating according to claim 2, characterized in that: The phenolamine is selected from any one of o-aminophenol, p-aminophenol and m-aminophenol, and is preferably o-aminophenol.

4. The high performance water-based automotive damping coating according to claim 2 or 3, characterized in that: The preparation method of the phenolamine-modified sodium carboxymethyl cellulose comprises the following steps: 1) dissolving sodium carboxymethyl cellulose in water, first adding acid to the aqueous solution to adjust the pH value, adding dicyclohexylcarbodiimide and N-hydroxysuccinimide to activate the carboxyl reaction, and then adding phenolamine to react at room temperature; 2) using ice-cold ether for precipitation, separation and drying to obtain phenolamine-modified sodium carboxymethyl cellulose.

5. The high performance water-based automotive damping coating according to claim 4, characterized in that: The mass ratio of the sodium carboxymethyl cellulose and the phenolamine is 40-50wt%:50-60wt%, based on the total mass of the sodium carboxymethyl cellulose and the phenolamine; and / or Adding acid to adjust the pH to pH 4.5-6.5; and / or The mass of dicyclohexylcarbodiimide added is 1-2wt% of the total mass of sodium carboxymethylcellulose and phenolamine, and the mass of N-hydroxysuccinimide added is 3-5wt% of the total mass of sodium carboxymethylcellulose and phenolamine; and / or The activation of the carboxyl group reaction has a reaction time of 30-60 min; and / or The reaction is carried out at room temperature and the reaction time is 2-5 hours.

6. The high performance water-based automotive damping coating according to any one of claims 1 to 5, characterized in that: The acrylic emulsion is a water-based acrylic emulsion with a Tg of 0-30° C., selected from one or more of Wanhua Chemical Antamp 0652, Antamp 0655, Antamp 0658, Antamp 0656, and Antamp 0657, preferably Antamp 0658.

7. The high performance water-based automotive damping coating according to any one of claims 1 to 5, characterized in that: The pigment filler is selected from at least one of carbon black, talcum powder, mica powder and calcium carbonate; Preferably, the carbon black is selected from at least one of FW-200 of Degussa (China) Co., Ltd. and N300 of Hebei Cangzhou Jintai Carbon Black Co., Ltd., preferably FW-200; and / or The calcium carbonate is selected from one or more of 325-mesh heavy calcium carbonate, 400-mesh heavy calcium carbonate, 700-mesh heavy calcium carbonate and 800-mesh heavy calcium carbonate produced by Changzhou Calcium Carbonate Co., Ltd., preferably 325-mesh heavy calcium carbonate and / or 400-mesh heavy calcium carbonate; and / or The mica powder is selected from at least any one of the 100-mesh mica powder of Chuzhou Sericite Co., Ltd. and the 200-mesh mica powder of Shijiazhuang Chenxing Industrial Co., Ltd.

8. The high performance water-based automotive damping coating according to any one of claims 1 to 5, characterized in that: The dispersant is selected from at least one of Orotan 731A of Dow (China) Co., Ltd., BYK 190 of BYK Chemical, Tego 760w of Tego, and C20 of Wanhua Chemical Group Co., Ltd., preferably any one of Tego 760w and Orotan 731A; and / or The thickener is selected from at least one of Vesmody A801, Vesmody A401 of Wanhua Chemical Group Co., Ltd. and ASE60 of Dow (China) Co., Ltd., preferably any one of Vesmody A801 ​​and ASE60; and / or The wetting agent is selected from at least one of Tego270, Tego280, Tego KL 245 of Digo (China) Co., Ltd. and Surfynol 104E of American Gas Chemical, preferably any one of Tego270 and KL 245; and / or The defoamer is selected from at least one of BASF Foam Star ST2410AC, BYK 810 of BYK Chemical, and Tego Foamex 1488, preferably any one of Foam Star ST2410AC and BYK 810; and / or The pH regulator is selected from at least one of AMP-95, ammonia water, and DMEA, preferably AMP-95.

9. The method for preparing the high-performance water-based automotive damping coating according to any one of claims 1 to 8, characterized in that: The following steps are involved: 1) mixing acrylic emulsion, dispersant, wetting agent, defoaming agent and pH regulator, and dispersing to obtain aqueous emulsion; 2) Mix deionized water, modified sodium carboxymethyl cellulose, and pigments and fillers, and disperse to obtain a mixed solution; 3) The mixed liquid of step 2) is mixed with the aqueous emulsion of step 1), and then a thickener is added to disperse to obtain the aqueous automotive damping coating.

10. The preparation method according to claim 9, characterized in that: The dispersion time of the dispersion in step 1) is 3-5 min; and / or The dispersion time in step 2) is 5-10 min; and / or The dispersion in step 3) is carried out in a disperser at a speed of 1000-1500 rpm for 10-15 minutes.

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