Wear-resistant water-based coating for automobile and preparation method thereof

Abstract

The invention relates to a wear-resistant water-based coating for an automobile and a preparation method of the wear-resistant water-based coating for the automobile. Comprising the following components in parts by weight: 48 to 52 parts of waterborne polyurethane dispersion, 13 to 17 parts of acrylate emulsion, 20 to 21 parts of deionized water, 2 to 4 parts of dipropylene glycol butyl ether, 2 to 3 parts of dipropylene glycol monomethyl ether, 0.4 to 0.6 part of dispersing agent, 0.4 to 0.5 part of defoaming agent, 0.1 to 0.2 part of wetting agent, 2 to 3 parts of matting powder, 0.2 to 0.3 part of flatting agent, 0.15 to 0.25 part of thickening agent and 4 to 5 parts of 95% ethanol. The surface smoothness is relatively high, and the wear resistance is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of automotive waterborne coatings, and in particular to a wear-resistant waterborne coating for automobiles and a preparation method thereof. Background Art

[0002] With the development of industrial economy and urbanization, it has also driven the rapid development of the automotive industry. The rapid development of the automotive industry has an obvious pulling effect on the automotive coating market, making automotive coatings the fastest-growing coating variety. Due to the extremely harsh working environment conditions of automobiles, being exposed to wind, sun, rain and snow all year round, strict requirements are put forward for the performance of automotive coatings. Currently, the automotive coatings used are mainly two types: solvent-based coatings and waterborne coatings; solvent-based coatings need to be formulated with organic solvents, and a large amount of organic solvents volatilize, which will cause great harm to the bodies of workers spraying the coatings, and at the same time pollute the air, resulting in serious environmental pollution. Therefore, since the 1990s, automotive coatings have begun to transform into waterborne automotive coatings.

[0003] Chinese Patent with publication number CN105368294A discloses a high-gloss impact-resistant environmentally friendly waterborne automotive coating and a preparation method thereof. This waterborne coating is prepared by mechanically blending modified waterborne polyurethane, nanoamino POSS, polytetrafluoroethylene micronized wax, deionized water, pigments and fillers, additives, and crosslinking agents in certain weight parts. Among them, the modified waterborne polyurethane is prepared by introducing titanium dioxide precursor and silica precursor into waterborne polyurethane by in-situ modification method, so that the nanoparticles are uniformly dispersed in the polyurethane emulsion in a directional arrangement. The coating has good leveling property, and the nanoparticles have no adverse effect on the appearance of the prepared automotive paint film. The obtained automotive paint film is flat, bright, has good adhesion, is scratch-resistant, has high gloss, and has excellent weather resistance and ultraviolet resistance; in addition, this invention patent introduces the impact-resistant component amino POSS into the coating, greatly enhancing the fastness of the paint layer, and the prepared waterborne coating has a low VOC content, meeting the environmental protection requirements of automotive coatings. However, the waterborne automotive coating prepared by this invention patent has low hardness, poor weather resistance, corrosion resistance and wear resistance, and does not have self-healing ability. Chinese Patent with publication number CN108070318A discloses a preparation method and application of a self-healing waterborne automotive coating, which fully combines the special physical and chemical properties of nano-silica and the advantages of polyurethane-based materials, and develops a self-healing waterborne automotive coating, enabling micro-damage to the body surface coating, especially internal damage that is not easily detected, to self-heal at the damaged part of the coating without using external repair materials, which has great value. However, the wear resistance performance of the waterborne automotive coating in this patent still needs to be further improved. Summary of the Invention

[0004] The purpose of the present invention is to provide a wear-resistant waterborne coating for automobiles, which can significantly improve the wear resistance of the automotive body paint surface.

[0005] To achieve the above object, a wear-resistant waterborne coating for automobiles is provided in the first aspect of the present invention. It is characterized in that the wear-resistant waterborne coating, by weight, comprises the following components: 48-52 parts of waterborne polyurethane dispersion, 13-17 parts of acrylate emulsion, 20-21 parts of deionized water, 2-4 parts of dipropylene glycol butyl ether, 2-3 parts of dipropylene glycol methyl ether, 0.4-0.6 parts of dispersant, 0.4-0.5 parts of defoamer, 0.1-0.2 parts of wetting agent, 2-3 parts of matting powder, 48-52 parts of waterborne polyurethane dispersion, 13-17 parts of acrylate emulsion, 20-21 parts of deionized water, 2-4 parts of dipropylene glycol butyl ether, 2-3 parts of dipropylene glycol methyl ether, 0.4-0.6 parts of dispersant, 0.4-0.5 parts of defoamer, 0.2-0.3 parts of flow agent, 0.15-0.25 parts of thickener, and 4-5 parts of 95% ethanol.

[0006] Further, the wear-resistant waterborne coating for automobiles, by weight, further comprises 3-4 parts of acrylic compatibilizer.

[0007] Further, the wear-resistant waterborne coating for automobiles, by weight, further comprises 2-3 parts of wear-resistant filler.

[0008] Further, the wear-resistant filler is quartz powder.

[0009] Further, the weight ratio of the waterborne polyurethane dispersion to the acrylate emulsion is 10:3.

[0010] Further, the thickener comprises RM-2020 thickener and RM-8W thickener.

[0011] Further, the weight ratio of the RM-2020 thickener to the RM-8W thickener is 1:1.

[0012] In the second aspect, the present invention also provides a preparation method of a wear-resistant waterborne coating for automobiles, comprising the following steps: S1: Weigh each raw material by weight. S2: Add the pre-prepared waterborne polyurethane dispersion and acrylate emulsion to deionized water, start stirring, disperse for 10-15 min under the condition of a rotation speed of 600-700 r / min, increase the rotation speed to 900-1100 r / min, and sequentially add dipropylene glycol butyl ether and dipropylene glycol methyl ether, and disperse for 15-25 min to obtain a mixed slurry. S3: Lower the rotational speed to 600 - 700 r / min, and sequentially add a dispersant, an antifoaming agent, a wetting agent, a matting powder, a leveling agent, a thickening agent, and 95% ethanol to the mixed slurry obtained in step S2, and disperse for 25 - 40 min to obtain a wear-resistant waterborne coating for automobiles after mixing evenly.

[0013] Further, in step S2, add the pre-prepared aqueous polyurethane dispersion and acrylate emulsion to deionized water, start stirring, disperse for 3 - 5 min under the condition of a rotational speed of 600 - 630 r / min, disperse for 3 - 5 min under the condition of a rotational speed of 630 - 670 r / min, disperse for 5 - 10 min under the condition of a rotational speed of 670 - 700 r / min, and then increase the rotational speed to 900 - 1100 r / min.

[0014] Further, in step S3, lower the rotational speed, and sequentially add a dispersant, an antifoaming agent, a wetting agent, a matting powder, a leveling agent, a thickening agent, and 95% ethanol to the mixed slurry obtained in step S2 under the condition of a rotational speed of 600 - 630 r / min, then disperse for 5 - 10 min, disperse for 5 - 8 min under the condition of a rotational speed of 630 - 670 r / min, and disperse for 5 - 7 min under the condition of a rotational speed of 670 - 700 r / min to obtain a mixed slurry.

[0015] The beneficial effects of the present invention are as follows: When the wear-resistant waterborne coating provided by the present invention is coated on a vehicle body, the surface smoothness is relatively high, and the wear resistance is improved. Description of the Drawings

[0016] Figure 1 is a top view schematic diagram of the automobile contact surface of the embodiment of the present invention.

[0017] Figure 2 is a cross-sectional schematic diagram of the wear-resistant waterborne coating filling the concave hole groove of the embodiment of the present invention.

[0018] Figure 3 is a cross-sectional schematic diagram of the concave hole groove of the embodiment of the present invention.

[0019] Explanation of the Reference Numerals in the Drawings 100, wear-resistant waterborne coating; 200, contact surface; 210, contact surface 200; 220, concave hole groove; 221, bottom wall; 222, surrounding wall; 223, chamfered part; 230, accommodation space. Detailed Embodiments

[0020] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the following further details the present invention's wear-resistant waterborne coating for automobiles and its preparation method in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0021] Automobile waterborne coatings include primer, intermediate coat paint, topcoat paint, clearcoat, etc. Since the successful development of electrophoretic coatings in the 1960s, it has become the standard painting method in the automotive industry. Currently, almost all small cars use electrophoretic primers. The reason why electrophoretic coatings can effectively avoid the "flash rust" layer and exhibit excellent anti-rust ability lies in its electrodeposition process. Taking cathodic electrophoretic paint as an example, the paint particles are deposited on the body metal plate under the action of an electric field to form a continuous and uniform coating, which forms a dense coating film after drying and crosslinking.

[0022] Anodic electrophoretic coatings are composed of water-soluble anionic resins, etc., while cathodic electrophoretic coatings are composed of water-soluble cationic resins, etc. Among them, the cationic resin coating film is alkaline, has a passivating effect on metals, and has excellent anti-corrosion performance. Currently, more than about 90% of automotive primers use cathodic electrophoretic coatings, which have high throwing power, thick coating films, good edge coverage, and significantly improved salt spray resistance. Cathodic electrophoretic coatings are not only used in automotive primers but also widely used in industries such as metal furniture, household appliances, building decoration, and small hardware.

[0023] In the first aspect of the present invention, a wear-resistant waterborne coating for automobiles is provided, which is characterized in that, by weight, the wear-resistant waterborne coating comprises the following components: 48 - 52 parts of waterborne polyurethane dispersion, 13 - 17 parts of acrylate emulsion, 20 - 21 parts of deionized water, 2 - 4 parts of dipropylene glycol butyl ether, 2 - 3 parts of dipropylene glycol methyl ether, 0.4 - 0.6 parts of dispersant, 0.4 - 0.5 parts of defoamer, 0.1 - 0.2 parts of wetting agent, 2 - 3 parts of matting powder, 0.2 - 0.3 parts of leveling agent, 0.15 - 0.25 parts of thickener, 4 - 5 parts of 95% ethanol. When this wear-resistant waterborne coating is applied to the vehicle body, the surface smoothness is relatively high, improving the wear resistance.

[0024] In some embodiments of the present invention, the wear-resistant waterborne coating 100 for automobiles, by weight, further comprises 3 - 4 parts of acrylic compatibilizer. The acrylic compatibilizer can graft acrylic acid onto polyolefin resin. The addition of acrylic compatibilizer and epoxy compatibilizer can reduce the surface tension between the two polymers, promote the dispersion of phases, prevent the coalescence of the dispersed phase, and in addition, can increase the thickness of the interfacial layer, increase the interfacial adhesion, improve the thermal stability, and increase the stress transfer efficiency.

[0025] In some embodiments of the present invention, the wear-resistant waterborne coating 100 for automobiles further includes 2-3 parts by weight of a wear-resistant filler, preferably quartz powder. The addition of quartz powder improves the wear resistance, dimensional stability, and thermal stability of the wear-resistant waterborne coating 100.

[0026] In some embodiments of the present invention, the weight ratio of the aqueous polyurethane dispersion to the acrylate emulsion is 10:3, and the waterborne matte paint prepared in this way has good surface smoothness.

[0027] In some embodiments of the present invention, the thickener includes RM-2020 thickener and RM-8W thickener. The combination of these two thickeners, a rheology aid that optimizes product performance in multiple aspects, ensures that the system maintains a uniform and stable suspension or emulsion state by enhancing system stability and increasing the viscosity of the system. It can also transform the system into a gel form, thus integrating multiple functions such as thickening, suspending, emulsifying, and stabilizing, and becoming a key additive to improve product quality and performance. Preferably, the weight ratio of RM-2020 thickener to RM-8W thickener is 1:1.

[0028] In the present invention, the aqueous polyurethane dispersion is Huajinsi R4188; the acrylate emulsion is Huajinsi HD1902; dipropylene glycol butyl ether is selected as DPnB; dipropylene glycol methyl ether is selected as DPM; the dispersant is selected as PA30; the defoamer is selected as BYK028; the wetting agent is selected as BYK346; the matting agent is selected as TS-100; the leveling agent is selected as Glide 440.

[0029] Therefore, a preferred formulation of the wear-resistant waterborne coating of the present invention, in parts by weight, is: 50 parts of Huajinsi R4188; 15 parts of Huajinsi HD1902; 20.70 parts of deionized water; 3 parts of DPnB; 2.5 parts of DPM; 0.5 part of PA30; 0.43 part of BYK028; 0.1 part of BYK346; 2.6 parts of TS-100; 0.26 part of Glide 440; 0.1 part of RM-2020; 0.1 part of RM-8W; 4.78 parts of 95% ethanol.

[0030] In addition, please refer to FIGS. 1-2. The present invention provides a wear-resistant waterborne coating 100 for automobiles. The automobile has a contact surface 200. The paint surface adhesion of the wear-resistant waterborne coating 100 provided on the contact surface 200 is x B, and the pencil hardness of the wear-resistant waterborne coating 100 is y H. The wear-resistant waterborne coating 100 satisfies: 1 / 2 ≤ x / y ≤ 5 / 3, where 3 ≤ x ≤ 5 and 3 ≤ y ≤ 6.

[0031] It should be noted that the unit of paint adhesion is B, and the unit of pencil hardness is H. There are various ways to apply the wear-resistant water-based coating 100 on the contact surface 200, such as brushing, dipping, air spraying, electrostatic spraying, electrophoretic coating, powder coating, etc. There is no limitation here as long as the wear-resistant water-based coating 100 can be attached to the contact surface 200. In addition, in the present invention, the contact surface of the vehicle can be the surface of the vehicle body, the surface of the vehicle interior, the surface of the engine housing, the surface of the wheel hub, etc. There is no limitation here as long as it can adhere to the wear-resistant water-based coating 100.

[0032] When the above-mentioned wear-resistant water-based coating 100 is provided on the contact surface 200 of the vehicle, and the paint adhesion of the wear-resistant water-based coating 100 on the contact surface 200 is x B, and the pencil hardness of the wear-resistant water-based coating is y H, the wear-resistant water-based coating satisfies: 1 / 2 ≤ x / y ≤ 5 / 3, where 3 ≤ x ≤ 5 and 3 ≤ y ≤ 6. In this way, the peeled area at the incision and the edge of the intersection is less than 10% in the paint adhesion test. Due to the improvement of the paint adhesion, when the vehicle provided with this wear-resistant water-based coating is scratched, the coating is not easily scratched off. And because the pencil hardness is relatively large, the depth of the scratch is effectively reduced. Therefore, the wear resistance of this wear-resistant water-based coating is effectively improved.

[0033] Please refer to Figure 2-3, in order to further improve the wear resistance of the wear-resistant water-based coating 100, the contact surface 200 includes a flat portion 210 and a plurality of concave grooves 220. The concave grooves 220 have a bottom wall 221 and a surrounding wall 222. The surrounding wall 222 is arranged circumferentially around the bottom wall 221. The bottom wall 221 and the surrounding wall 222 form an accommodation space 230. From the side of the surrounding wall 222 away from the bottom wall 221 to the side where the surrounding wall 222 is connected to the bottom wall 221, the cross-sectional area of the surrounding wall 222 shows a decreasing trend. The side of the surrounding wall 222 away from the bottom wall 221 is connected to the flat portion 210; a part of the wear-resistant water-based coating 100 fills the accommodation space 230, and another part of the wear-resistant water-based coating 100 is arranged on the surface of the flat portion 210. Through this setting, since the cross-sectional area of the surrounding wall 222 shows a decreasing trend from the side of the surrounding wall 222 away from the bottom wall 221 to the side where the surrounding wall 222 is connected to the bottom wall 221, the wear-resistant water-based coating 100 can more easily and quickly enter the accommodation space 230 and be filled. And the part of the wear-resistant water-based coating 100 in the accommodation space 230 has a stronger adhesion ability than the other part of the wear-resistant water-based coating 100 attached to the flat portion 210, because the total contact area of the part of the wear-resistant water-based coating 100 in the accommodation space 230 with the surrounding wall 222 and the bottom wall 221 is larger. When rubbing occurs, the part of the wear-resistant water-based coating 100 in the accommodation space 230 is not easily scraped off. In this way, it also avoids the situation that in a large-area scraping area of the vehicle body, part of the wear-resistant water-based coating 100 on the flat portion 210 is scraped off, but the part of the wear-resistant water-based coating 100 in the accommodation space 230 is not affected. When performing the paint adhesion test, the part of the wear-resistant water-based coating 100 in the accommodation space 230 is not easily adhered away, which can further reduce the proportion of the peeled area at the incision and the intersection edge, and control the proportion of the peeled area at the incision and the intersection edge within 5%.

[0034] As a preferred embodiment, please refer to Figure 3 , the accommodation space 230 is frustum-shaped, the accommodation space 230 has a circular opening, the bottom wall 221 is a circular bottom wall, the surrounding wall 222 is a frustum surrounding wall, and the wear-resistant water-based coating 100 enters the accommodation space 230 through the circular opening and fills the accommodation space 230. The diameter of the circular opening is larger than the diameter of the bottom wall 221. Setting the accommodation space 230 to be frustum-shaped not only has a simple process and low cost, but also the contact area of the circular surface and the arc surface is the largest compared to the contact areas of other regular shapes. The larger the contact area, the stronger the adhesion of the part of the wear-resistant water-based coating 100 in the accommodation space 230, thereby improving the wear resistance of the wear-resistant water-based coating 100 provided on the contact surface 200.

[0035] As a preferred embodiment, please refer to Figure 3, a chamfered portion 223 is provided on one side of the surrounding wall 222 away from the bottom wall 221. The radian of the chamfered portion 223 is π / 4 to π / 3. One end of the chamfered portion 223 is connected to one side of the surrounding wall 222 away from the bottom wall 221, and the other end of the chamfered portion 223 is connected to the flat portion 210. The setting of the chamfered portion 223 makes it such that when rubbing occurs, the object in contact and the chamfer will present a geometric tangency relationship, changing the previous surface contact into point contact. In this way, the part of the wear-resistant and water-based coating 100 filled in the accommodation space 230 is not easily scraped off, and the chamfered portion 223 plays an important protective role. In addition, the selected radian of the chamfered portion 223 is π / 4 to π / 3, which can reduce the influence on the overall structural strength of the vehicle body and ensure the stability of the overall structural strength of the vehicle body.

[0036] In one embodiment, the wear-resistant filler is quartz powder, and the addition of quartz powder improves the wear resistance, dimensional stability, and thermal stability of the wear-resistant and water-based coating 100.

[0037] In one embodiment, the pigment is at least one of titanium dioxide and carbon black; the dispersant is sodium hexametaphosphate; the defoamer is at least one of GPE-type polyoxyethylene polyoxypropylene glycerol ether and modified silicone defoamer; the leveling agent is at least one of water-based acrylate copolymer, fluorine-modified polyacrylate copolymer, and polyether-modified polysiloxane polymer; the anti-settling agent is any one of bentonite and EVA wax; the wetting agent is at least one of ethanol, propylene glycol, and glycerol; the film-forming aid is at least one of dipropylene glycol butyl ether and dipropylene glycol methyl ether.

[0038] Example 1

[0039] A wear-resistant and water-based coating for an automobile, by weight, comprises the following components: 48 parts of aqueous polyurethane dispersion, 13 parts of acrylate emulsion, 20 parts of deionized water, 2 parts of dipropylene glycol butyl ether, 2 parts of dipropylene glycol methyl ether, 0.4 part of dispersant, 0.4 part of defoamer, 0.1 part of wetting agent, 2 parts of matting powder, 0.1 part of leveling agent, 0.15 part of thickener, 4 parts of 95% ethanol.

[0040] And, a plurality of concave grooves 220 with a spacing of five microns are provided on the contact surface 200. The accommodation space 230 of the concave grooves 220 is frustum-shaped. The bottom wall diameter of the concave grooves 220 is five microns, the circular opening diameter of the accommodation space 230 is ten microns, and the depth of the accommodation space 230 in the diameter direction is five microns.

[0041] Example 2

[0042] A wear-resistant and water-based coating for an automobile, by weight, comprises the following components: 50 parts of aqueous polyurethane dispersion, 15 parts of acrylate emulsion, 20.70 parts of deionized water, 3 parts of dipropylene glycol butyl ether, 2.5 parts of dipropylene glycol methyl ether, 0.5 part of dispersant, 0.43 part of defoamer, 0.1 part of wetting agent, 2.6 parts of matting powder, 0.26 part of leveling agent, 0.2 part of thickener, 4.78 parts of 95% ethanol.

[0043] Moreover, a number of concave grooves 220 with a spacing of five microns are provided on the contact surface 200. The accommodation space 230 of the concave groove 220 is frustum-shaped. The bottom wall diameter of the concave groove 220 is five microns, the circular opening diameter of the accommodation space 230 is ten microns, and the radial depth of the accommodation space 230 is five microns.

[0044] Example Three

[0045] A wear-resistant aqueous coating for automobiles, by weight, comprises the following components: 52 parts of aqueous polyurethane dispersion, 17 parts of acrylate emulsion, 21 parts of deionized water, 4 parts of dipropylene glycol butyl ether, 3 parts of dipropylene glycol methyl ether, 0.6 part of dispersant, 0.5 part of defoamer, 0.2 part of wetting agent, 3 parts of matting powder, 0.3 part of leveling agent, 0.2 part of thickener, 5 parts of 95% ethanol.

[0046] Moreover, a number of concave grooves 220 with a spacing of five microns are provided on the contact surface 200. The accommodation space 230 of the concave groove 220 is frustum-shaped. The bottom wall diameter of the concave groove 220 is five microns, the circular opening diameter of the accommodation space 230 is ten microns, and the radial depth of the accommodation space 230 is five microns.

[0047] Example Four

[0048] A wear-resistant aqueous coating for automobiles, by weight, comprises the following components: 49 parts of aqueous polyurethane dispersion, 15 parts of acrylate emulsion, 20 parts of deionized water, 2 parts of dipropylene glycol butyl ether, 2.5 parts of dipropylene glycol methyl ether, 0.4 part of dispersant, 0.4 part of defoamer, 0.1 part of wetting agent, 2 parts of matting powder, 0.2 part of leveling agent, 0.15 part of thickener, 4.6 parts of 95% ethanol.

[0049] Moreover, a number of concave grooves 220 with a spacing of five microns are provided on the contact surface 200. The accommodation space 230 of the concave groove 220 is frustum-shaped. The bottom wall diameter of the concave groove 220 is five microns, the circular opening diameter of the accommodation space 230 is ten microns, and the radial depth of the accommodation space 230 is five microns.

[0050] Comparative Example One The formulation ratio of the wear-resistant aqueous coating is the same as that of Example One, but the concave groove 220 is not provided on the contact surface 200.

[0051] Comparative Example 2 The wear-resistant waterborne coating, by weight, comprises the following components: 48 - 52 parts of aqueous polyurethane dispersion, 13 - 17 parts of acrylate emulsion, 20 - 21 parts of deionized water, 1 part of dipropylene glycol butyl ether, 1 part of dipropylene glycol methyl ether, 0.3 part of dispersant, 0.3 part of defoamer, 0.08 part of wetting agent, 1.8 parts of matting powder, 0.1 part of leveling agent, 0.1 part of thickener, and 3 parts of 95% ethanol.

[0052] Moreover, a number of concave grooves 220 with a spacing of five microns are provided on the contact surface 200. The accommodation space 230 of the concave groove 220 is frustum-shaped. The bottom wall diameter of the concave groove 220 is five microns, the circular opening diameter of the accommodation space 230 is ten microns, and the radial depth of the accommodation space 230 is five microns.

[0053] Comparative Example 3 The wear-resistant waterborne coating, by weight, comprises the following components: 53 parts of aqueous polyurethane dispersion, 18 parts of acrylate emulsion, 22 parts of deionized water, 5 parts of dipropylene glycol butyl ether, 4 parts of dipropylene glycol methyl ether, 0.7 part of dispersant, 0.6 part of defoamer, 0.3 part of wetting agent, 4 parts of matting powder, 0.4 part of leveling agent, 0.3 part of thickener, and 6 parts of 95% ethanol.

[0054] Moreover, a number of concave grooves 220 with a spacing of five microns are provided on the contact surface 200. The accommodation space 230 of the concave groove 220 is frustum-shaped. The bottom wall diameter of the concave groove 220 is five microns, the circular opening diameter of the accommodation space 230 is ten microns, and the radial depth of the accommodation space 230 is five microns.

[0055] Comparative Example 4 The formulation ratio of the wear-resistant waterborne coating 100 is the same as that of Comparative Example 2, but the concave grooves 220 are not provided on the contact surface 200.

[0056] For the above Examples 1 - 4 and Comparative Examples 1 - 4, the preparation process of the wear-resistant waterborne coating 100 comprises the following steps: S1: Weigh each raw material by weight. S2: Add the pre-prepared composite slurry of aqueous hydroxyl resin, modified aqueous polyurethane resin, and aqueous acrylic resin into deionized water, start stirring, disperse for 10 - 15 min under the condition of a rotation speed of 600 - 700 r / min, then increase the rotation speed to 900 - 1100 r / min, and sequentially add the compatibilizer, wear-resistant filler, wear-resistant filler, wear-resistant filler, and disperse for 15 - 25 min to obtain a mixed slurry. S3: Lower the rotational speed to 600 - 700 r / min, and sequentially add a dispersant, an antifoaming agent, a leveling agent, an anti-settling agent, a wetting agent, and a film-forming auxiliary agent to the mixed slurry obtained in step S2, and disperse for 25 - 40 min. After mixing evenly, an abrasion-resistant waterborne coating for automobiles is obtained.

[0057] In order to make the mixing in the feeding and mixing stage more uniform, we can adopt the following two preferred embodiments: (1) In step S2, add the pre-prepared aqueous polyurethane dispersion and acrylate emulsion to deionized water, start stirring, disperse for 3 - 5 min under the condition of a rotational speed of 600 - 630 r / min, disperse for 3 - 5 min under the condition of a rotational speed of 630 - 670 r / min, disperse for 5 - 10 min under the condition of a rotational speed of 670 - 700 r / min, and then raise the rotational speed to 900 - 1100 r / min.

[0058] (2) In step S3, lower the rotational speed, and sequentially add a dispersant, an antifoaming agent, a wetting agent, a matting powder, a leveling agent, a thickening agent, and 95% ethanol to the mixed slurry obtained in step S2 under the condition of a rotational speed of 600 - 630 r / min, and then disperse for 5 - 10 min, disperse for 5 - 8 min under the condition of a rotational speed of 630 - 670 r / min, and disperse for 5 - 7 min under the condition of a rotational speed of 670 - 700 r / min to obtain a mixed slurry.

[0059] We conduct a paint adhesion test and a pencil hardness test on the abrasion-resistant waterborne coatings 100 of Examples 1 - 4 and Comparative Examples 1 - 4 obtained by the above preparation method to obtain the following table data.

[0060] Table 1

[0061] By analyzing the above table, we can know that: (1) When the abrasion-resistant waterborne coating satisfies: 1 / 2 ≤ x / y ≤ 5 / 3, 3 ≤ x ≤ 5, 3 ≤ y ≤ 6, the proportion of the peeled area at the incision and the intersection edge is within 10%.

[0062] (2) When the abrasion-resistant waterborne coating satisfies: 1 / 2 ≤ x / y ≤ 5 / 3, 3 ≤ x ≤ 5, 3 ≤ y ≤ 6, and a number of concave grooves are provided on the contact surface, the proportion of the peeled area at the incision and the intersection edge is within 5%.

[0063] Based on the above analysis, when the wear-resistant water-based coating is provided on the contact surface of the vehicle, and the paint adhesion of the wear-resistant water-based coating on the contact surface is x B, and the pencil hardness of the wear-resistant water-based coating is y H, the wear-resistant water-based coating satisfies: 1 / 2 ≤ x / y ≤ 5 / 3, where 3 ≤ x ≤ 5 and 3 ≤ y ≤ 6. In this way, the proportion of the peeled area at the incision and the edge of the intersection in the paint adhesion test is less than 10%. Due to the improvement of the paint adhesion, when the vehicle with this wear-resistant water-based coating is scratched, the coating is not easily scratched off. And due to the relatively large pencil hardness, the depth of the scratch is effectively reduced. Therefore, the wear resistance of this wear-resistant water-based coating is effectively improved. Further optimization, when a number of concave grooves are provided on the contact surface, the proportion of the peeled area at the incision and the edge of the intersection in the paint adhesion test can be controlled within 5%.

[0064] Performance Test Paint Adhesion Test: 1. First, use a utility knife or a crosshatch cutter to make a cross-shaped pattern on the paint coating, making one horizontal and one vertical cut to form one hundred small squares, with each square being 1mm × 1mm. The incision of the crosshatch cutter should reach the bottom layer of the paint.

[0065] 2. Use a brush to brush in the diagonal direction five or six times each to clean up the small fragments, then stick the tape on the incision and pull it off. The adhesion of the tape is 350 - 400 g / m².

[0066] 3. Finally, use a magnifying glass to observe the situation in the grid area and calculate the proportion of the peeled area at the incision and the edge of the intersection.

[0067] For the above paint adhesion test standard, please refer to the American National Standard ANSI / ASTM D3359 - 87 "Adhesion by Tape Test".

[0068] Pencil Hardness Test: 1) Place the test piece upward and fix it. Hold the pencil hardness tester at a 45° angle to the test piece and draw forcefully without breaking the lead core. Draw about 1 cm forward at a uniform speed in the direction of the tester. The scratching speed is 1 mm / s. After one scratch, the tip of the lead core should be re-ground, and the test should be repeated 5 times with the pencil hardness tester of the same hardness mark.

[0069] 2) When evaluating by observing the damage of the coating film, when only 2 or fewer tests show the substrate or the primer coating film in 5 tests, a pencil with a hardness mark one level higher should be used for the same test. When the damage of the coating film reaches more than 2 times (per 5 tests), the hardness mark of the pencil hardness tester at this time can be read, and the hardness mark one level lower than this pencil hardness mark should be noted.

[0070] The pencil hardness tester is made according to the manual operation method in Article 2.3 of the national standard GB 6739-86 "Pencil Hardness Method for Film Hardness", and belongs to a kind of scratch hardness testing instrument. It is a simple and fast method for testing the hardness of coatings. The sharp edge of a pencil is used to scratch the surface of the coating to test the hardness of the coating. The pencil hardness tester consists of an instrument body, rollers, HB pencils and fastening screws.

[0071] The working principle of the pencil hardness tester: The pencil hardness tester contacts the surface to be measured at three points (two points are the rollers and one point is the pencil lead). It always ensures that the angle between the pencil and the surface to be measured is 45°. According to the lever principle, the pressure applied by the main body of the hardness tester on the pencil lead is (1 ± 0.05) kg.

[0072] The above is only a preferred embodiment of the present invention, and does not impose any form of limitation on the present invention. Although the present invention has been disclosed above with a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments by using the above-disclosed technical content within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A wear-resistant water-based coating for automobiles, characterized in that, The wear-resistant waterborne coating comprises the following components in parts by weight: 48-52 parts of a waterborne polyurethane dispersion, 13-17 parts of an acrylate emulsion, 20-21 parts of deionized water, 2-4 parts of dipropylene glycol butyl ether, 2-3 parts of dipropylene glycol methyl ether, 0.4-0.6 part of a dispersant, 0.4-0.5 part of an antifoaming agent, 0.1-0.2 part of a wetting agent, 2-3 parts of a matting powder, 0.2-0.3 part of a leveling agent, 0.15-0.25 part of a thickener, and 4-5 parts of 95% ethanol.

2. The wear-resistant water-based coating for an automobile according to claim 1, characterized in that, The wear-resistant waterborne coating for automobiles further comprises 3-4 parts of an acrylic compatibilizer in parts by weight.

3. The wear-resistant water-based coating for an automobile according to claim 1, characterized in that, The wear-resistant waterborne coating for automobiles further comprises 2-3 parts of a wear-resistant filler in parts by weight.

4. The wear-resistant water-based coating for automobiles according to claim 3, characterized in that, The wear-resistant filler is quartz powder.

5. A wear-resistant waterborne coating for automobiles according to claim 1, characterized in that, The weight ratio of the waterborne polyurethane dispersion to the acrylate emulsion is 10:

3.

6. The wear-resistant water-based coating for automobiles according to claim 1, characterized in that The thickener comprises RM-2020 thickener and RM-8W thickener.

7. An abrasion-resistant waterborne coating for automobiles according to claim 6, characterized in that, The weight ratio of the RM-2020 thickener to the RM-8W thickener is 1:

1.

8. A method for preparing a wear-resistant waterborne coating for automobiles according to any one of claims 1-7, characterized in that, It includes the following steps: S1: Weigh each raw material according to parts by weight; S2: Add the pre-prepared waterborne polyurethane dispersion and acrylate emulsion into deionized water, start stirring, disperse for 10-15 min under the condition of a rotation speed of 600-700 r / min, raise the rotation speed to 900-1100 r / min, and sequentially add dipropylene glycol butyl ether and dipropylene glycol methyl ether, and disperse for 15-25 min to obtain a mixed slurry; S3: Lower the rotation speed to 600-700 r / min, sequentially add a dispersant, an antifoaming agent, a wetting agent, a matting powder, a leveling agent, a thickener, and 95% ethanol into the mixed slurry prepared in step S2, and disperse for 25-40 min to mix evenly to obtain the wear-resistant waterborne coating for automobiles.

9. The preparation method of a wear-resistant water-based coating for an automobile according to claim 8, characterized in that, In step S2, add the pre-prepared waterborne polyurethane dispersion and acrylate emulsion into deionized water, start stirring, disperse for 3-5 min under the condition of a rotation speed of 600-630 r / min, disperse for 3-5 min under the condition of a rotation speed of 630-670 r / min, disperse for 5-10 min under the condition of a rotation speed of 670-700 r / min, and then raise the rotation speed to 900-1100 r / min.

10. The preparation method of a wear-resistant waterborne coating for automobiles according to claim 9, characterized in that, In step S3, lower the rotation speed, sequentially add a dispersant, an antifoaming agent, a wetting agent, a matting powder, a leveling agent, a thickener, and 95% ethanol into the mixed slurry prepared in step S2 under the condition of a rotation speed of 600-630 r / min, then disperse for 5-10 min, disperse for 5-8 min under the condition of a rotation speed of 630-670 r / min, and disperse for 5-7 min under the condition of a rotation speed of 670-700 r / min to obtain a mixed slurry.

Images