A bifunctional modified acrylic emulsion for whole vehicle water-based damping coating, a preparation method and application thereof

Abstract

The present application relates to a kind of whole vehicle water-based damping coating with bifunctional modified acrylic emulsion and its preparation method and application, belong to the cross field of synthesis and coating.It includes the following components, acrylic acid 0.5-1 part, methyl methacrylate 10-20 parts, butyl acrylate 20-30 parts, urea phosphate type methacrylate special monomer 3-7 parts, anionic emulsifier 1-2 parts, nonionic emulsifier 0.5-1 part, initiator 0.1-0.25 part, chain transfer agent 0.1-1 part, deionized water 40-55 parts;When preparing, first synthesize urea phosphate type methacrylate special monomer, the monomer contains dynamic hydrogen bond type urea group and metal chelating type phosphate group, graft copolymerization is carried out on high molecular main chain by polymerizable double bond, the synergistic effect of both, create composite bifunctional modified acrylic emulsion system.Can make coating high-temperature baking construction property to 190 DEG C, after multiple humidity and heat cycle still have higher loss factor.

Description

Technical Field

[0001] This invention relates to the field of synthesis and coatings, specifically to a bifunctional modified acrylic emulsion for waterborne damping coatings for vehicles, its preparation method, and its application. More specifically, it relates to a method of first synthesizing a special monomer of urea phosphate methacrylate, and then using this monomer to synthesize a high-performance modified acrylic emulsion, which is particularly suitable for the field of automotive damping coatings. Background Technology

[0002] Waterborne damping coatings (LASD) for automobiles have seen significant development due to their convenient application methods and green, sustainable characteristics. However, given the increasingly challenging international trade environment, how to improve product performance amidst price wars has become a problem that automotive raw material suppliers need to consider and solve.

[0003] Currently, water-based damping coatings generally suffer from the following problems: 1. Most companies require the coating to withstand high-temperature baking at 100℃-150℃ after application. After high-temperature baking, the resulting coating needs to meet the requirements of no blistering and no cracking. If the material can withstand higher baking temperatures, the production cycle can be shortened and production efficiency improved; 2. Currently, most manufacturers focus on the workability of the material, that is, its high-temperature baking performance, while neglecting to improve the sound insulation and noise reduction performance of the damping coating itself; 3. Insufficient attention is paid to coatings in high-temperature and high-humidity coastal areas. Existing research and development directions mainly consider the problem of coating cracking and peeling caused by corrosion, and cannot guarantee that it will still have a high damping value after multiple humid heat cycles.

[0004] Taking into full account the cost of raw materials, in order to overcome the above problems and improve performance, it is necessary to develop a high-performance modified acrylic emulsion for use in automotive damping coatings. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a bifunctional modified acrylic emulsion for automotive waterborne damping coatings, its preparation method, and its application. This method first synthesizes a special monomer of urea phosphate-type methacrylate, which is then copolymerized onto the polymer backbone via polymerizable double bond grafting to synthesize a composite bifunctional modified acrylic emulsion system. When applied to automotive damping coatings, it significantly improves product performance.

[0006] The objective of this invention is achieved through the following technical solution: a bifunctional modified acrylic emulsion for waterborne damping coatings for vehicles, comprising the following components by weight: 0.5-1 parts acrylic acid, 10-20 parts methyl methacrylate, 20-30 parts butyl acrylate, 3-7 parts urea phosphate-type methacrylate special monomer, 1-2 parts anionic emulsifier, 0.5-1 part nonionic emulsifier, 0.1-0.25 parts initiator, 0.1-1 part chain transfer agent, and 40-55 parts deionized water.

[0007] The urea phosphate type methacrylate special monomer has the following structure.

[0008] .

[0009] The above-mentioned bifunctional modified acrylic emulsion for waterborne damping coatings for vehicles, wherein the preparation method of the special monomer of urea phosphate methacrylate is as follows.

[0010] 2-Aminoethyl dihydrogen phosphate was completely dissolved in acetone, a polymerization inhibitor was added, and then methacryloyloxyethyl isocyanate was slowly added dropwise. The two reacted to obtain the target product, urea phosphate methacrylate, a special monomer, through an addition reaction. The dropwise addition time was 3 hours, the addition reaction time was 5 hours, and the reaction temperature was controlled at 20-25℃.

[0011] The above-mentioned waterborne damping coating for vehicles uses a bifunctional modified acrylic emulsion, wherein the ratio of 2-aminoethyl dihydrogen phosphate: methacryloyloxyethyl isocyanate: acetone is 10 mol: 10 mol: 100-200 mL, and the polymerization inhibitor is hydroquinone, with a concentration of 100-500 ppm.

[0012] The aforementioned bifunctional modified acrylic emulsion for waterborne damping coatings for vehicles uses an anionic emulsifier that is one or more of the following: sodium alkyl alcohol ether sulfosuccinate A102, sodium alkylphenol ether sulfosuccinate MS1, sodium dioctyl sulfosuccinate OT-75, and fatty acid methyl ester sulfonate MES.

[0013] The aforementioned bifunctional modified acrylic emulsion for waterborne damping coatings for vehicles uses one or more of the following nonionic emulsifiers: nonylphenol polyoxyethylene ether TX-10, octylphenol polyoxyethylene ether OP-10, and Pingpingjia O-10.

[0014] The aforementioned bifunctional modified acrylic emulsion for water-based damping coatings for vehicles uses one or more of ammonium persulfate, sodium persulfate, and potassium persulfate as the initiator.

[0015] The aforementioned bifunctional modified acrylic emulsion for waterborne damping coatings used in vehicles uses a chain transfer agent that is one or more of n-dodecyl mercaptan, tert-dodecyl mercaptan, isooctyl 3-mercaptopropionate, and α-methylstyrene dimer.

[0016] The preparation method of the above-mentioned bifunctional modified acrylic emulsion for waterborne damping coatings for vehicles includes the following steps.

[0017] Step 1: Thoroughly mix 20-25 parts of deionized water, 1-1.5 parts of anionic emulsifier, 0.5-1 part of acrylic acid, 10-20 parts of methyl methacrylate, 20-30 parts of butyl acrylate, and 3-7 parts of urea phosphate type methacrylate special monomer, and disperse for 20 minutes to form a uniform and stable pre-emulsion.

[0018] Add 20-30 parts of deionized water, 0.2-0.5 parts of anionic emulsifier, and 0.5-1 parts of nonionic emulsifier to the reaction vessel, heat to 85℃, add 1 / 10 of the pre-emulsion and 1 / 3 of the initiator solution, and react for 15 minutes to obtain the seed liquid.

[0019] Step 2: Add 0.1-1 part of chain transfer agent to the remaining 9 / 10 of the pre-emulsion. In the seed solution, add the remaining 9 / 10 of the pre-emulsion and 2 / 3 of the initiator solution dropwise over 4 hours and keep warm for 2 hours.

[0020] Step 3: Cool down to 40℃, adjust pH to 8.0, and discharge to obtain high-performance modified acrylic emulsion.

[0021] An application of the above-mentioned bifunctional modified acrylic emulsion in the preparation of waterborne damping coatings for vehicles, wherein the waterborne damping coating comprises, by weight, 5-10 parts deionized water, 30-35 parts high-performance modified acrylic emulsion, 1-3 parts additives, and 60-70 parts filler, stirred evenly, dispersed at high speed, and the viscosity adjusted.

[0022] In the above-mentioned application of bifunctional modified acrylic emulsion in the preparation of water-based damping coatings for vehicles, the additives are one or more of wetting agents, dispersants, and thickeners, and the fillers are one or more of talc powder, mica powder, wollastonite powder, and heavy calcium carbonate powder.

[0023] The advantages of this invention compared to the prior art are as follows.

[0024] 1. Construct a urea-phosphate bifunctional composite modified resin system by simultaneously introducing dynamic hydrogen-bonded urea groups and metal-chelated phosphate groups during acrylic emulsion polymerization. The two complement each other and synergistically enhance each other, creating a composite modified system.

[0025] 2. High-temperature baking resistance and workability: The polar groups of phosphate esters carry a high negative potential, which can greatly increase the stability of the damping coating system. Together with the urea groups, they provide strong interfacial bonding force, effectively resisting film shrinkage stress. The coating can be dried in a 190℃ high-temperature oven without cracking, blistering or peeling.

[0026] 3. High damping and resistance to damp heat: The urea functional groups can form a large number of hydrogen bonds. When vibration acts on the surface of the damping coating, the multidimensional hydrogen bonds inside continuously break and reassociate, converting a large amount of mechanical energy into internal energy and significantly improving the loss factor. At the same time, the urea groups have a dipole coordination effect with the metal substrate, which can improve adhesion, especially wet adhesion, so that the material still has a high loss factor after multiple damp heat cycles.

[0027] 4. Improved salt spray resistance: Phosphate groups can form chelate coordination reactions with metal substrates to generate phosphates, which enhances the adhesion between the material and the substrate, solves the corrosion problem, and is suitable for coastal areas with high humidity and high salt, avoiding coating peeling due to substrate corrosion. Attached Figure Description

[0028] Figure 1 This is the infrared spectrum of the urea phosphate type methacrylate special monomer prepared in step 1 of Example 1. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to embodiments, but is not limited thereto.

[0030] Unless otherwise stated, all raw materials used in the examples are commercially available industrial products.

[0031] Example 1.

[0032] Step 1. Synthesize the special monomer of urea phosphate methacrylate.

[0033] The four-necked flask was purged with nitrogen. 1271g of 2-aminoethyl dihydrogen phosphate was added and dissolved thoroughly in 100ml of acetone. Then, 1.4g of hydroquinone, a polymerization inhibitor, was added, and the mixture was stirred for 20 minutes. Next, 1551g of methacryloyloxyethyl isocyanate was slowly added dropwise over 3 hours. After the addition was complete, stirring was continued for a total reaction time of 5 hours, with the reaction temperature controlled at 20-25℃ throughout. After the reaction, acetone was removed by vacuum distillation, yielding a light yellow, transparent, viscous liquid, which is the urea phosphate type methacrylate monomer. Its structural formula is as follows.

[0034] .

[0035] Its infrared spectrum is shown below. Figure 1 2270cm -1 No peak was observed, indicating that NCO had reacted completely; 3362.83 cm⁻¹ -1 The peak represents the stretching effect of urea bond NH and P-OH association; 2932.46 cm⁻¹ -1 This is the absorption peak of saturated CH; 1740.46 cm⁻¹ -1 / 1716.19cm -1The peak is the C=O absorption peak, which splits into two peaks due to the influence of hydrogen bonds in adjacent urea bonds; 1639.8 cm⁻¹ -1 The peak is a C=C absorption peak, partially obscured and not fully visible; 1529.23 cm⁻¹ -1 The absorption peak is from the NH bending + CN stretching coupling of ureaamide (amide II band); 1247.24 cm⁻¹ -1 The presence of the P=O absorption peak confirms the presence of a special monomer of urea phosphate-type methacrylate.

[0036] Step 2. Prepare high-performance modified acrylic emulsion.

[0037] First, thoroughly mix 20 parts deionized water, 0.4 parts fatty acid methyl ester sulfonate (MES), 0.6 parts sodium sulfosuccinate alkyl alcohol ether ester (A102), 0.5 parts acrylic acid, 17 parts methyl methacrylate, 25 parts butyl acrylate, and 5 parts urea phosphate methacrylate special monomers, and disperse for 20 minutes to form a uniform and stable pre-emulsion.

[0038] Next, add 20 parts of deionized water, 0.25 parts of sodium alkyl alcohol ether sulfosuccinate A102, and 0.5 parts of nonionic emulsifier to the reaction vessel, heat to 85°C, add 1 / 10 of the pre-emulsion and 1 / 3 of the initiator solution, and react for 15 minutes to obtain the seed liquid.

[0039] Then, add 1 part chain transfer agent to the remaining pre-emulsion. Add the remaining 9 / 10 of the pre-emulsion and 2 / 3 of the initiator solution dropwise to the seed culture over 4 hours, followed by incubation for 2 hours.

[0040] Finally, the temperature was lowered to 40°C, the pH was adjusted to 8.0, and the high-performance modified acrylic emulsion was obtained by discharging.

[0041] Step 3. Preparation of automotive damping coating.

[0042] Add 5 parts deionized water to 30 parts high-performance modified acrylic emulsion, and disperse at 500 rpm with high-speed stirring. Then add 1.5 parts quick-dispersing agent and 0.5 parts PE-100 wetting agent, and continue dispersing for 5 minutes. Next, turn on planetary stirring and the temperature control system, maintaining a constant temperature of 20°C. Add 5 parts talc powder, 3 parts mica powder, 10 parts wollastonite, and 45 parts heavy calcium carbonate, and disperse at 2000 rpm for 10 minutes. Turn off high-speed dispersion and maintain planetary stirring for 20 minutes before discharging.

[0043] Comparative Example 1.

[0044] The difference from Example 1 is that the addition of the special monomer of urea phosphate methacrylate is omitted, and it is replaced with 3 parts butyl acrylate and 3 parts butyl methacrylate. Other raw materials and experimental steps are the same as step 2 of Example 1.

[0045] Comparative Example 2.

[0046] The difference from Example 1 is that the addition of the special monomer of urea phosphate methacrylate is omitted, and it is replaced with 6 parts of methacrylamide ethyl ethylene urea. Other raw materials and experimental steps are the same as step 2 of Example 1.

[0047] Comparative Example 3.

[0048] The difference from Example 1 is that the addition of the special monomer of urea phosphate methacrylate is omitted, and it is replaced with 6 parts of 2-hydroxyethyl methacrylate phosphate. Other raw materials and experimental steps are the same as step 2 of Example 1.

[0049] Comparative Example 4.

[0050] The difference from Example 1 is that the addition of the special monomer of urea phosphate type methacrylate is omitted, and it is replaced with 3 parts of methacrylamide ethyl ethylene urea and 3 parts of 2-hydroxyethyl methacrylate phosphate. Other raw materials and experimental steps are the same as step 2 of Example 1.

[0051] Comparative Example 5.

[0052] Commercially available water-based damping coatings used by automobile OEMs.

[0053] Performance testing section.

[0054] (a) Emulsion properties.

[0055] The main focus was on investigating the polymerization stability, appearance, and viscosity of the high-performance modified acrylic emulsion of this invention.

[0056] The testing method is as follows.

[0057] 1. Polymerization stability: Visual inspection showed no slag discharge, rapid polymerization, particle coarsening, or oil separation during the polymerization process.

[0058] 2. Appearance: Visual inspection.

[0059] 3. Emulsion viscosity: Tested using an NDJ-5S rotational viscometer.

[0060] (ii) Damping coating performance.

[0061] 1. High-temperature baking appearance test.

[0062] High-temperature baking blistering performance test of water-based damping coating: The water-based damping coating was applied to the electrophoretic paint plate with a thickness of 3mm. The sample was directly placed at 190℃ for 20 minutes to cure and the cracking and blistering of the coating were observed.

[0063] 2. Damping test.

[0064] Damping tests were conducted according to GB / T18258-2000 "Test Methods for Damping Performance of Damping Materials". Standard sample preparation: cold-rolled sheet 220mm × 10mm × 1.6mm, with a density of 4.0 kg / m³ after coating and drying. 2 The coating was cured under the following conditions: 150℃ for 20 minutes. The damping value was obtained by testing with a damping test system.

[0065] 3. Damp heat cycling test.

[0066] On a 220mm×10mm×0.8mm electrophoretic steel plate, after coating and drying, the density is 4.0kg / m³. 2 The coating was kept at 150±2℃ for 15 minutes, cooled at 23±2℃, and then cyclicated 4 times (80℃×15.5h→23℃×0.5h→-30℃×7.5h→23℃×0.5h→50℃×95%RH×15.5h→23℃×0.5h→-30℃×7.5h). After returning to room temperature, it was observed whether there was blistering, cracking, or peeling, and then the damping value was tested.

[0067] 4. Salt spray resistance test.

[0068] The electrophoretic plate is coated with a 3mm thick water-based damping coating, baked at 150℃ for 20 minutes to cure, and then cured at room temperature for 24 hours. Crosses are drawn on the coating surface, and the plate is placed in a neutral salt spray chamber for 500 hours. The erosion of the electrophoretic plate is observed. If the erosion is ≤1mm, it is considered qualified.

[0069] Note: To ensure the accuracy of test data, the test strips and salt spray samples must be free of blistering and cracking after drying, with a uniform and flat surface. The drying temperature should be uniformly changed to 150℃.

[0070] The results of the emulsion testing are shown in Table 1 below.

[0071] Table 1. Results of emulsion testing.

[0072]

[0073] The acrylic emulsions obtained in Comparative Examples 1-4 were used to prepare damping coatings according to the method in step 3 of Example 1. The test results of the damping coatings obtained in step 3 of Example 1 are shown in Table 2 below.

[0074] Table 2 Damping coating test.

[0075]

[0076] The test results in the two tables above show that the emulsion prepared by the method of this invention has good polymerization stability and moderate viscosity. When applied to damping coatings, it can improve the coating's high-temperature baking resistance and workability up to 190℃, and still maintain a high loss factor after multiple humid heat cycles, significantly improving product performance.

[0077] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any modifications, substitutions, or improvements based on the present invention are within the protection scope of the present invention.

Claims

1. A bifunctional modified acrylic emulsion for waterborne damping coatings used in vehicles, characterized in that, The product comprises the following components by weight: 0.5-1 part acrylic acid, 10-20 parts methyl methacrylate, 20-30 parts butyl acrylate, 3-7 parts urea phosphate type methacrylate special monomer, 1-2 parts anionic emulsifier, 0.5-1 part nonionic emulsifier, 0.1-0.25 parts initiator, 0.1-1 part chain transfer agent, and 40-55 parts deionized water. The urea phosphate type methacrylate special monomer has the following structure: 。 2. The bifunctional modified acrylic emulsion for waterborne damping coatings for vehicles according to claim 1, characterized in that, The method for preparing the urea phosphate type methacrylate special monomer is as follows: 2-Aminoethyl dihydrogen phosphate was completely dissolved in acetone, a polymerization inhibitor was added, and then methacryloyloxyethyl isocyanate was slowly added dropwise. The two reacted to obtain the target product, urea phosphate methacrylate, a special monomer, through an addition reaction. The dropwise addition time was 3 hours, the addition reaction time was 5 hours, and the reaction temperature was controlled at 20-25℃.

3. The bifunctional modified acrylic emulsion for waterborne damping coatings for vehicles according to claim 2, characterized in that, The ratio of 2-aminoethyl dihydrogen phosphate: methacryloyloxyethyl isocyanate: acetone is 10 mol: 10 mol: 100-200 mL, and the polymerization inhibitor is hydroquinone, with a concentration of 100-500 ppm.

4. The bifunctional modified acrylic emulsion for waterborne damping coatings for vehicles according to claim 1, characterized in that, The anionic emulsifier is one or more of the following: sodium alkyl alcohol ether sulfosuccinate A102, sodium alkylphenol ether sulfosuccinate MS-1, sodium dioctyl sulfosuccinate OT-75, and fatty acid methyl ester sulfonate MES.

5. The bifunctional modified acrylic emulsion for waterborne damping coatings for vehicles according to claim 1, characterized in that, The nonionic emulsifier is one or more of nonylphenol polyoxyethylene ether TX-10, octylphenol polyoxyethylene ether OP-10, and Pingpingjia O-10.

6. The bifunctional modified acrylic emulsion for waterborne damping coatings for vehicles according to claim 1, characterized in that, The initiator is one or more of ammonium persulfate, sodium persulfate, and potassium persulfate.

7. The bifunctional modified acrylic emulsion for waterborne damping coatings for vehicles according to claim 1, characterized in that, The chain transfer agent is one or more of n-dodecyl mercaptan, tert-dodecyl mercaptan, isooctyl 3-mercaptopropionate, and α-methylstyrene dimer.

8. A method for preparing a bifunctional modified acrylic emulsion for a waterborne damping coating for vehicles according to any one of claims 1-7, characterized in that, Includes the following steps: Step 1: Thoroughly mix 20-25 parts of deionized water, 1-1.5 parts of anionic emulsifier, 0.5-1 part of acrylic acid, 10-20 parts of methyl methacrylate, 20-30 parts of butyl acrylate, and 3-7 parts of urea phosphate type methacrylate special monomer, and disperse for 20 minutes to form a uniform and stable pre-emulsion. Add 20-30 parts of deionized water, 0.2-0.5 parts of anionic emulsifier, and 0.5-1 parts of nonionic emulsifier to the reaction vessel, heat to 85℃, add 1 / 10 of the pre-emulsion and 1 / 3 of the initiator solution, and react for 15 minutes to obtain the seed liquid; Step 2: Add 0.1-1 part of chain transfer agent to the remaining 9 / 10 of the pre-emulsion. Add the remaining 9 / 10 of the pre-emulsion and 2 / 3 of the initiator solution dropwise to the seed solution over 4 hours and keep warm for 2 hours. Step 3: Cool down to 40℃, adjust pH to 8.0, and discharge to obtain high-performance modified acrylic emulsion.

9. The application of the bifunctional modified acrylic emulsion according to any one of claims 1-7 in the preparation of waterborne damping coatings for vehicles, characterized in that: Includes 5-10 parts deionized water, 30-35 parts high-performance modified acrylic emulsion, 1-3 parts additives, and 60-70 parts filler. Stir evenly, disperse at high speed, and adjust viscosity.

10. The application of the bifunctional modified acrylic emulsion according to claim 9 in the preparation of waterborne damping coatings for vehicles, characterized in that: The water-based damping coating for vehicles, by weight, comprises one or more of the following additives: wetting agent, dispersant, and thickener; and one or more of the following filler: talc powder, mica powder, wollastonite powder, and heavy calcium carbonate powder.

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