A high-performance, environmentally friendly waterborne damping coating and its preparation method

Abstract

This invention provides a high-performance, environmentally friendly waterborne damping coating and its preparation method. The high-performance, environmentally friendly waterborne damping coating comprises the following raw materials in parts by weight: 20-30 parts emulsion, 3-5 parts water, 5-15 parts modified porous adsorption medium, 20-30 parts filler, 5-10 parts wetting agent, 5-10 parts thickener, 1-5 parts thixotropic agent, 1-5 parts anti-aging agent, and 1-5 parts dispersant. This invention adds a betaine-type surfactant-modified porous adsorption medium to the coating to adsorb VOCs in the coating. The porous adsorption medium, with a large number of macropores, mesopores, and micropores, is selected to increase its specific surface area, allowing for sufficient friction between it and the emulsion molecules, thereby improving the damping effect and increasing its adsorption area. This invention also adds an orientation agent to the coating to constrain the arrangement of the modified porous adsorption medium and filler in the coating, preventing their aggregation, adhesion, or stacking, effectively increasing the friction between the emulsion molecules and both, thus improving the damping effect.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to a high-performance, environmentally friendly water-based damping coating and its preparation method. Background Technology

[0002] With the development of the times and social progress, people's demands for living standards are getting higher and higher. As an important part of "clothing, food, housing, and transportation," cars have become one of the main focuses of society. Among them, damping coatings, as part of vehicle interiors, have better corrosion resistance, wear resistance, and weather resistance compared to damping materials such as damping plates. Damping coatings are composed of polymer materials and fillers with specific functions. Due to the obvious viscoelasticity of polymer materials, they can absorb a portion of the vibration energy and release it in the form of "heat," which is called mechanical loss, and thus produces damping performance for vibration reduction and noise reduction.

[0003] However, with increasingly stringent national environmental protection requirements, damping coatings inevitably need to further reduce VOCs. Currently, commercially available water-based damping coatings incorporate natural graphite to reduce VOCs. However, natural graphite has low surface tension, no defects, and strong hydrophobicity, all of which worsen the coating's flowability and weaken the effect of the polymer material, thereby reducing the coating's damping performance. Furthermore, natural graphite tends to aggregate and cannot be uniformly dispersed in water-based damping coatings, resulting in porous and non-dense coatings. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a high-performance environmentally friendly water-based damping coating to solve the problem that adding natural graphite to reduce VOCs in the prior art will lead to the loss of damping performance. At the same time, this invention will also provide a method for preparing the high-performance environmentally friendly water-based damping coating.

[0005] To achieve the above and other related objectives, the present invention provides the following technical solutions:

[0006] In a first aspect, the present invention provides a high-performance environmentally friendly waterborne damping coating comprising the following raw materials in parts by weight: 20-30 parts emulsion, 3-5 parts water, 5-15 parts modified porous adsorption medium, 20-30 parts filler, 5-10 parts wetting agent, 5-10 parts thickener, 1-5 parts thixotropic agent, 1-5 parts anti-aging agent, and 1-5 parts dispersant.

[0007] Emulsions can dissipate the mechanical energy of transmitted sound waves into heat energy through the friction of their internal molecular chains. The higher the loss factor of the coating, the wider the damping temperature range and the better the damping performance. To adjust the damping performance of the coating in different temperature ranges, it needs to be obtained by mixing different emulsions with different temperatures (Tg). This helps to comprehensively improve the damping effect of the coating. According to the specifications, Tg is divided into high Tg, medium Tg, and low Tg; Tg > 40℃ is high Tg; Tg < -10℃ is low Tg; and -10℃ ≤ Tg ≤ 40℃ is medium Tg.

[0008] In one optional embodiment, the emulsion includes, but is not limited to, acrylic emulsions and polyurethane emulsions. Acrylic emulsions and polyurethane emulsions have very similar prices, are non-toxic and harmless at room temperature, and possess properties such as oil resistance, abrasion resistance, low-temperature resistance, and aging resistance. Furthermore, the two selected polymers cure quickly at room temperature, are easy to apply, and have strong adhesion.

[0009] In a preferred embodiment, every 100 parts by weight of emulsion is obtained by mixing 70-80 parts by weight of acrylic emulsion and 30-20 parts by weight of polyurethane emulsion, and the mixed emulsion needs to be stirred evenly in advance.

[0010] Furthermore, the acrylic emulsion is composed of 40-60 parts by weight of medium Tg acrylic emulsion and 30-10 parts by weight of low Tg acrylic emulsion.

[0011] This invention incorporates a porous adsorption medium into the coating. The porous adsorption medium can slowly adsorb small molecule organic compounds volatilized from the coating at room temperature, thereby indirectly reducing the VOC of the coating.

[0012] In one optional embodiment, the porous adsorption medium includes at least one of porous graphite, porous activated carbon, and porous carbon nanotubes.

[0013] The porous graphite, porous activated carbon, and porous carbon nanotubes selected in this invention possess numerous macropores, mesopores, and micropores, increasing the specific surface area of ​​the materials. On one hand, this allows for sufficient friction between the emulsion molecules and the material, enhancing the damping effect; on the other hand, it increases the adsorption area of ​​the porous adsorption medium, improving its VOC adsorption capacity. Furthermore, the mesopores and macropores penetrating the bulk phase give the porous adsorption medium a foam-like porous morphology. The addition of the porous adsorption medium results in a higher foaming rate in the coating, promotes the movement of emulsion molecules, increases the loss factor, and improves the damping effect.

[0014] Furthermore, the specific surface area of ​​the porous adsorption medium is 1200–3200 m². 2 / g.

[0015] Furthermore, the modification method of the modified porous adsorption medium is as follows: the porous adsorption medium is uniformly dispersed in a solution containing a betaine-type surfactant, stirred thoroughly, filtered, washed, and dried to obtain the modified porous adsorption medium.

[0016] By utilizing the special structure of betaine-type surfactants, their hydrophobic ends are adsorbed on the surface of porous adsorption media, while their hydrophilic ends point towards the water, thereby improving the hydrophilicity of the porous adsorption media and significantly enhancing its wettability.

[0017] This invention utilizes betaine-type surfactants to modify porous adsorption media. Betaine-type surfactants exhibit anionic surfactant properties in alkaline aqueous solutions, demonstrating excellent foaming and detergency effects; while in acidic solutions, they exhibit cationic surfactant properties, possessing strong bactericidal capabilities with lower toxicity than cationic surfactants. Furthermore, betaine-type surfactants also possess excellent UV resistance, effectively preventing UV damage to coating components, extending the coating's lifespan, and reducing VOCs generated during decomposition.

[0018] In one optional embodiment, the filler includes one or more of sepiolite, diatomaceous earth, wood flour, heavy calcium carbonate (calcium carbonate), and their modifiers.

[0019] Furthermore, to reduce bubbling on the baked surface, the filler is also formulated with a small amount of starch.

[0020] Furthermore, the modification method of the filler modifier is as follows: the filler and the surface modifier are mixed, stirred and allowed to stand in a high-speed mixer to prepare the filler modifier; wherein, the surface modifier is selected from one or more of sodium stearate, calcium stearate, phosphate ester and Stan 80.

[0021] Surface modification of fillers with surface modifiers increases their HLB value and compatibility with the emulsion matrix, resulting in more uniform dispersion of fillers in coatings and preventing sedimentation.

[0022] Furthermore, the filler is preferably modified heavy calcium carbonate. The modified heavy calcium carbonate is prepared by mixing, stirring, and allowing to stand in a high-speed mixer with 12.5 to 13.5 parts by weight of heavy calcium carbonate and 0.5 to 1.5 parts by weight of surface modifier.

[0023] In one optional embodiment, the waterborne damping coating further includes 1 to 5 parts by weight of an oriented alignment agent, wherein the oriented alignment agent includes inorganic oriented alignment agents and organic oriented alignment agents.

[0024] Furthermore, the inorganic directional alignment agent includes lamellar silicates, preferably lithium magnesium silicates / lithium magnesium sodium silicate. Lamellar silicates have a structure similar to natural hantoitite, enabling them to form a "house" structure that constrains the arrangement of the modified porous adsorbent medium and fillers in the coating, resulting in a more uniform array distribution. This prevents the aggregation or adhesion of the modified porous adsorbent medium and fillers, effectively increasing the frictional interaction between the emulsion molecules and the fillers, thereby enhancing the damping effect.

[0025] Furthermore, the organic directional alignment agent includes at least one of modified hydroxyethyl cellulose and cellulose acetate butyrate.

[0026] Among them, modified hydroxyethyl cellulose and cellulose acetate butyrate have relatively low molecular weights and are not completely miscible with emulsion molecules. Their polar groups have a strong attraction to fillers, and due to their low surface tension, they generate a shrinkage force during coating drying, pulling the porous adsorption medium and fillers in the planar direction and preventing them from stacking in the height direction. This results in directional alignment, improving the damping performance of waterborne damping coatings. Furthermore, because modified hydroxyethyl cellulose and cellulose acetate butyrate contain hydroxyl groups, they can crosslink with emulsion molecules, improving the flexibility of the coating after drying.

[0027] In one optional embodiment, the viscosity of the water-based damping coating is adjusted by adding a thickener so that the viscosity of the water-based damping coating is 75~95 mPa·s at 20 rpm and 25°C.

[0028] In one optional embodiment, the thixotropic agent includes at least one of bentonite and fumed silica.

[0029] In one optional embodiment, the anti-aging agent is a polyol phosphate. The addition of the anti-aging agent results in a longer service life for the waterborne damping coating and prevents the decomposition of the waterborne damping coating material from generating new VOC sources.

[0030] In one optional embodiment, the dispersant is selected from at least one of phosphoramide dispersants, modified polyacrylic acid dispersants, and modified polycarboxylate dispersants.

[0031] In one optional embodiment, the water-based damping coating further includes 1 to 5 parts of other additives, including but not limited to antioxidants, surfactants, plasticizers, and bactericides. When starch is added as a filler, it is preferable to formulate a small amount of bactericide to prevent starch deterioration. Since betaine-type surfactants are introduced into the coating through a modified porous adsorption medium and have a certain bactericidal effect, the amount of bactericide added can be reduced or eliminated when starch is added as a filler.

[0032] In a second aspect, the present invention provides a method for preparing a high-performance environmentally friendly waterborne damping coating, comprising the following steps: slowly adding emulsion, water, directional alignment agent, wetting agent, thickener, thixotropic agent, and dispersant in sequence, stirring, then adding filler, modified porous adsorption medium, and anti-aging agent, and stirring to obtain a high-performance environmentally friendly waterborne damping coating.

[0033] The stirring speed is 400~600 rpm, the stirring time is greater than 20 min, and the stirring temperature is between 25℃ and 35℃; the preferred stirring speed is 500 rpm.

[0034] As described above, the high-performance environmentally friendly water-based damping coating and its preparation method of the present invention have the following beneficial effects:

[0035] 1. This invention adds a betaine-type surfactant-modified porous adsorption medium to the coating, which improves the damping performance of the coating and adsorbs small molecule organic matter escaping from the coating, thus solving the VOC problem at its source. Furthermore, the porous adsorption medium with a large number of macropores, mesopores and micropores is selected to increase its specific surface area. On the one hand, this allows for sufficient friction between the medium and the emulsion molecules, improving the damping effect; on the other hand, it increases the adsorption area, thereby improving its ability to adsorb VOCs.

[0036] 2. The present invention adds an orientation agent to the coating to constrain the arrangement of the modified porous adsorption medium and filler in the coating, so that they are distributed in a more uniform planar array, preventing the agglomeration, adhesion or stacking of the modified porous adsorption medium and filler, effectively improving the friction between the emulsion molecules and the two, thereby improving the damping effect.

[0037] 3. This invention modifies the surface of the filler by using a surface modifier to increase its HLB value and compatibility with the emulsion matrix, making the filler more evenly dispersed in the coating and avoiding sedimentation.

[0038] 4. This invention adds an anti-aging agent to the coating to ensure that the water-based damping coating does not easily age and decompose during use, thereby preventing the escape of small molecule organic matter and reducing VOC. Detailed Implementation

[0039] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0040] Example 1

[0041] A high-performance, environmentally friendly waterborne damping coating comprises the following raw materials in parts by weight: 12 parts medium-Tg acrylic emulsion, 9 parts low-Tg acrylic emulsion, 9 parts polyurethane emulsion, 5 parts ordinary tap water, 10 parts betaine-type surfactant-modified porous graphite, 20 parts modified heavy calcium carbonate, 5 parts flake silicate, 5 parts wetting agent, 5 parts thickener, 1 part thixotropic agent, 1 part anti-aging agent, and 1 part dispersant; wherein the specific surface area of ​​the porous graphite is between 2600 and 2800 m². 2 / g.

[0042] Example 2

[0043] A high-performance, environmentally friendly waterborne damping coating comprises the following raw materials in parts by weight: 12 parts medium-Tg acrylic emulsion, 9 parts low-Tg acrylic emulsion, 9 parts polyurethane emulsion, 5 parts ordinary tap water, 10 parts betaine-type surfactant-modified porous activated carbon, 20 parts modified heavy calcium carbonate, 5 parts flake silicate, 5 parts wetting agent, 5 parts thickener, 1 part thixotropic agent, 1 part anti-aging agent, and 1 part dispersant; wherein the specific surface area of ​​the porous activated carbon is between 1400 and 1600 m². 2 / g.

[0044] Example 3

[0045] A high-performance, environmentally friendly waterborne damping coating comprises the following raw materials in parts by weight: 12 parts medium-Tg acrylic emulsion, 9 parts low-Tg acrylic emulsion, 9 parts polyurethane emulsion, 5 parts ordinary tap water, 10 parts betaine-type surfactant-modified porous carbon nanotubes, 20 parts modified heavy calcium carbonate, 5 parts flake silicate, 5 parts wetting agent, 5 parts thickener, 1 part thixotropic agent, 1 part anti-aging agent, and 1 part dispersant; wherein the specific surface area of ​​the porous carbon nanotubes is between 3000 and 3200 m². 2 / g.

[0046] Example 4

[0047] A high-performance, environmentally friendly waterborne damping coating comprises the following raw materials in parts by weight: 12 parts medium-Tg acrylic emulsion, 9 parts low-Tg acrylic emulsion, 9 parts polyurethane emulsion, 5 parts ordinary tap water, 10 parts betaine-type surfactant-modified porous graphite, 20 parts modified heavy calcium carbonate, 5 parts cellulose acetate butyrate, 2 parts wetting agent, 5 parts thickener, 1 part thixotropic agent, 1 part anti-aging agent, and 1 part dispersant; wherein the specific surface area of ​​the porous graphite is between 2600 and 2800 m². 2 / g.

[0048] Example 5

[0049] A high-performance, environmentally friendly waterborne damping coating comprises the following raw materials in parts by weight: 10 parts medium-Tg acrylic emulsion, 6 parts low-Tg acrylic emulsion, 8 parts polyurethane emulsion, 5 parts ordinary tap water, 10 parts betaine-type surfactant-modified porous graphite, 20 parts modified heavy calcium carbonate, 3 parts cellulose acetate butyrate, 2 parts modified hydroxyethyl cellulose, 5 parts wetting agent, 5 parts thickener, 1 part thixotropic agent, 1 part anti-aging agent, and 1 part dispersant; wherein the specific surface area of ​​the porous graphite is between 2600 and 2800 m². 2 / g.

[0050] Comparative Example 1

[0051] A water-based damping coating comprises the following raw materials in parts by weight: 12 parts medium-Tg acrylic emulsion, 9 parts low-Tg acrylic emulsion, 9 parts polyurethane emulsion, 5 parts ordinary tap water, 10 parts betaine-type surfactant-modified porous graphite, 20 parts modified heavy calcium carbonate, 5 parts flake silicate, 5 parts wetting agent, 5 parts thickener, 1 part thixotropic agent, 1 part anti-aging agent, and 1 part dispersant; wherein the specific surface area of ​​the porous graphite is between 400 and 600 m². 2 / g.

[0052] Comparative Example 2

[0053] A water-based damping coating comprises the following raw materials in parts by weight: 12 parts medium-Tg acrylic emulsion, 9 parts low-Tg acrylic emulsion, 9 parts polyurethane emulsion, 5 parts ordinary tap water, 10 parts unmodified porous graphite, 20 parts modified heavy calcium carbonate, 5 parts flake silicate, 5 parts wetting agent, 5 parts thickener, 1 part thixotropic agent, 1 part anti-aging agent, and 1 part dispersant; wherein the specific surface area of ​​the porous graphite is between 2600 and 2800 m². 2 / g.

[0054] Comparative Example 3

[0055] A water-based damping coating comprises the following raw materials in parts by weight: 12 parts medium-Tg acrylic emulsion, 9 parts low-Tg acrylic emulsion, 9 parts polyurethane emulsion, 5 parts ordinary tap water, 10 parts betaine-type surfactant-modified porous graphite, 20 parts modified heavy calcium carbonate, 5 parts wetting agent, 5 parts thickener, 1 part thixotropic agent, 1 part anti-aging agent, and 1 part dispersant; wherein the specific surface area of ​​the porous graphite is between 2600 and 2800 m². 2 / g.

[0056] Comparative Example 4

[0057] A water-based damping coating comprises the following raw materials in parts by weight: 12 parts medium-Tg acrylic emulsion, 9 parts low-Tg acrylic emulsion, 9 parts polyurethane emulsion, 5 parts ordinary tap water, 10 parts betaine-type surfactant-modified porous graphite, 20 parts modified heavy calcium carbonate, 5 parts flake silicate, 5 parts wetting agent, 5 parts thickener, 1 part thixotropic agent, and 1 part dispersant; wherein the specific surface area of ​​the porous graphite is between 2600 and 2800 m². 2 / g.

[0058] The performance of the waterborne damping coatings prepared in Examples 1-5 was tested, and the test results are shown in Table 1.

[0059] Table 1. Performance test results of waterborne damping coatings in Examples 1-5

[0060]

[0061] The performance of the waterborne damping coatings prepared in Example 1 and Comparative Examples 1-4 was tested, and the test results are shown in Table 2.

[0062] Table 2. Performance test results of waterborne damping coatings in Examples 1 and Comparative Examples 1-4

[0063]

[0064] The VOC testing method is as follows:

[0065]

[0066] The passing criteria for VOC testing are as follows:

[0067]

[0068] According to the test results of Examples 1 to 5, the high-performance environmentally friendly water-based damping coating prepared by the present invention has high damping performance and good stability during use, and can continuously adsorb VOCs.

[0069] A comparison of the test results from Example 1 and Comparative Examples 1-2 shows that adding unmodified porous adsorbent media causes repulsion between the porous adsorbent media and the coating matrix, leading to aggregation of the porous adsorbent media and its inability to be uniformly dispersed in the coating. This results in a significant reduction in the coating's damping performance and also affects the adsorption of VOCs by the porous adsorbent media, leading to excessively high VOC content. If the added modified porous media has too few mesopores, its specific surface area is too small, reducing the frictional interaction with emulsion molecules and lowering the damping performance. Furthermore, its surface modification is insufficient, resulting in poor compatibility with the coating and a tendency to agglomerate.

[0070] A comparison of the test results of Example 1 and Comparative Example 3 shows that if no directional alignment agent is added to the coating, the modified porous adsorption medium and filler will agglomerate, stick, and stack, which will not only affect the mechanical properties of the coating, but also reduce its damping performance. However, after adding the directional alignment agent, the directional alignment agent will constrain the arrangement of the modified porous adsorption medium and filler, making them present a more uniform planar array distribution, thereby effectively improving the friction between the emulsion molecules and the two, and thus improving the damping effect.

[0071] In summary, this invention adds a betaine-type surfactant-modified porous adsorption medium to the coating to adsorb VOCs in the coating. Furthermore, it selects a porous adsorption medium with a large number of macropores, mesopores, and micropores to increase its specific surface area. This, on the one hand, allows for sufficient friction between the medium and emulsion molecules, improving the damping effect; on the other hand, it increases the adsorption area, enhancing its VOC adsorption capacity. To prevent the agglomeration of the porous adsorption medium and filler, which reduces damping performance, this invention adds an orientation agent to the coating. This agent constrains the arrangement of the modified porous adsorption medium and filler in the coating, ensuring a more uniform planar array distribution. This prevents the agglomeration, adhesion, or stacking of the modified porous adsorption medium and filler, effectively increasing the frictional interaction between the emulsion molecules and both, thereby improving the damping effect. Therefore, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0072] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A high performance environmentally friendly waterborne damping paint, characterized in that, The raw materials include the following weight parts: 20-30 parts of emulsion, 3-5 parts of water, 5-15 parts of porous adsorption medium modified by betaine surfactant, 20-30 parts of filler, 5-10 parts of wetting agent, 5-10 parts of thickening agent, 1-5 parts of thixotropic agent, 1-5 parts of anti-aging agent, and 1-5 parts of dispersing agent, 1-5 parts of directional arrangement agent; The directional arrangement agent is inorganic and organic, the organic one including at least one of modified hydroxyethyl cellulose and cellulose acetate butyrate; the inorganic one is sheet silicate; the sheet silicate forms a "card house" structure, which restricts the modified porous adsorption medium and filler in the paint to be distributed in a more uniform array; The modification method of the betaine surfactant modified porous adsorption medium is: uniformly dispersing the porous adsorption medium in a solution containing a betaine surfactant, fully stirring, filtering, washing, and drying to obtain the betaine surfactant modified porous adsorption medium; the porous adsorption medium comprises at least one of porous graphite, porous activated carbon, and porous carbon nanotubes, and the specific surface area of the porous adsorption medium is 1200-3200 m 2 / g.

2. The high performance environmentally friendly waterborne damping paint according to claim 1, characterized in that, The emulsion includes at least two emulsions with different Tg. 3.The high-performance environment-friendly water-based damping paint of claim 1, wherein, 70-80 parts of acrylic emulsion and 30-20 parts of polyurethane emulsion are mixed to obtain 100 parts of emulsion. The acrylic emulsion is composed of 40-60 parts of medium Tg acrylic emulsion and 30-10 parts of low Tg acrylic emulsion.

4. The high performance environmentally friendly waterborne damping paint according to claim 1, characterized in that, The high-performance environmentally friendly water-based damping paint has a viscosity of 75-95 mPa·s at 20 rpm and 25℃.

5. A method for preparing the high performance environmentally friendly waterborne damping coating according to any one of claims 1 to 4, characterized in that, The method includes the following steps: sequentially and slowly adding emulsion, water, directional arrangement agent, wetting agent, thickening agent, thixotropy, dispersing agent, stirring, and then adding filler, porous adsorption medium modified by betaine surfactant, and anti-aging agent, and stirring to obtain a high-performance environmentally friendly water-based damping paint.

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