High-blackness water-based refinishing paint composition as well as preparation method and application thereof

Abstract

The invention provides a high-blackness water-based refinishing paint composition as well as a preparation method and application thereof. The water-based refinishing paint composition comprises the following components in parts by mass: 10-30 parts of color paste serving as a coloring component, and the color paste comprises at least one pigment for providing color and / or optical effect; 20-45 parts of a water-based resin as a film-forming component, wherein the water-based resin comprises at least one polyurethane dispersion; 4-20 parts of a rheological aid for adjusting rheological properties, comprising at least one organic thickener and at least one inorganic thickener; wherein the pigment is high pigment carbon black, accounts for 10-25% of the mass of the color paste, and is selected from one or more of Cabot # imgabs 0 # 2000, # imgabs 1 # 5000 # imgabs 2 # III and Orion FW310. The water-based refinishing paint composition has the characteristics of high blackness and high stability, can better cater to the fashion trend of automobile colors, and meets the requirements on the storage stability of automobile refinishing paint in practical application, so that the water-based refinishing paint composition has wider market requirements.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile repair paint preparation, and specifically comprises a high-blackness water-based repair paint composition and a preparation method and application thereof. Background Art

[0002] As people pursue beauty and individuality in life, cars, as high-end consumer goods, often lead the fashion trend in color design; car body color is the most important first impression given to people, and consumers are pursuing it more and more extreme, brewing high-end black concepts such as Darth Vader, King Kong Black, and Dark Black.

[0003] While the original paint is pursuing this ultimate effect, car repair paint, as the back-end market of car maintenance, also needs to follow closely. Consumers' requirements for car repair are also increasing. The car repair industry should ensure that the finished result is equivalent to the original finish in terms of vision and technology. However, the construction conditions in the car repair process are different from those of the original paint. For example, spraying and baking are different from the painting production line of general factories. There is no single operation. The car models and color requirements to be painted are different. It is impossible to operate in the prescribed process sequence, and the baking temperature does not exceed 80°C, otherwise it will damage the plastic accessories. Moreover, under normal circumstances, the shelf life requirements for water-based repair paint are significantly higher than those for the original paint. The shelf life of the original paint is usually half a year, while the repair paint usually requires 1-2 years, and some are even 2-4 years. Therefore, the repair paint must not only meet and match the excellent appearance color and performance requirements of the original paint, but also requires good storage stability.

[0004] For improving the blackness of the black color of automobile paint, it is currently mainly concentrated in the solvent-based coating system, such as Chinese patent CN106046983A discloses a solvent-based blue phase special black automobile topcoat and its preparation method, and the blue phase special black automobile topcoat has good weather resistance, leveling, and wear resistance through the matching of each component of the formula, and the blackness, brightness, and fullness are high, and the hue is blue; Chinese patent CN102146245A discloses a solvent-based blue phase special black automobile repair paint, through the formula design, the blackness is deep enough, and its performance and hue effect can meet the market requirements of high-end products. However, for the field of water-based repair paint with high long-term stability requirements, not only the blackness of the coating should be paid attention to, but also the storage stability should be paid attention to, in order to prevent the coating from returning to coarseness, precipitation and other problems, and the high blackness coating has higher requirements for stability, and there is no patent related to the preparation technology of water-based repair paint composition with high blackness published so far. In view of this, it is necessary to provide a new water-based repair paint composition to better cater to the popular trend of automobile color. Summary of the invention

[0005] In view of the above problems existing in the prior art, the first object of the present invention is to provide a water-based repair paint composition with high blackness. The water-based repair paint composition has the characteristics of high blackness and high stability. After heat storage at 50°C for 3 months, its fineness, viscosity, color difference and blackness will not change significantly. The stability is significantly higher than the existing technical level and has a broader market demand.

[0006] The second object of the present invention is to provide a method for preparing the above-mentioned high-blackness water-based repair paint composition.

[0007] The third object of the present invention is to provide an application of the above-mentioned high-blackness water-based repair paint composition in the field of automobile repair.

[0008] A fourth object of the present invention is to provide a use of the high-blackness water-based repair paint composition as described above in the preparation of a water-based paint product for automobile repair.

[0009] To achieve the above first object, the technical solution adopted by the present invention includes:

[0010] The present invention discloses a water-based repair paint composition, which comprises 10-30 parts by mass of a color paste as a coloring component, wherein the color paste comprises at least one pigment providing color and / or providing optical effect;

[0011] 20-45 parts of an aqueous resin as a film-forming component, which comprises at least one polyurethane dispersion;

[0012] 4-20 parts of a rheological additive for adjusting rheological properties, comprising at least one organic thickener and at least one inorganic thickener; and

[0013] 5-58 parts of water;

[0014] The pigment is high-color carbon black, accounting for 10-25% of the color paste mass, which is selected from Cabot 2000, 5000 III and Orion FW310.

[0015] Further, in percentage by mass, the color paste also comprises

[0016] Wetting agent 1-5%;

[0017] Dispersant 20-59%;

[0018] Defoaming agent 0.2-2%;

[0019] pH adjuster 0.2-2%;

[0020] The rest is water.

[0021] Furthermore, the D90 of the color paste is ≤200nm.

[0022] Furthermore, the wetting agent is selected from one or more of Surfynol 104A, Surfynol 104BC, and Carbowet GA-210.

[0023] Further, the dispersant is selected from DISPERBYK-2014, DispexUltraPX4585, Solsperse TM One or more of W210.

[0024] Furthermore, the defoaming agent is selected from one or more of Foamstar SI 2280, BYK-011, and BYK-024.

[0025] Furthermore, the polyurethane dispersion is selected from one or more of polycarbonate-modified polyurethane dispersion, aliphatic waterborne polyurethane dispersion, and aliphatic polycarbonate-type waterborne polyurethane dispersion.

[0026] Furthermore, the average particle size of the polyurethane dispersion is ≤60 nm.

[0027] Further, the rheological additive comprises 0.5-5 parts of an organic thickener and 3-15 parts of an inorganic thickener;

[0028] The organic thickener is selected from one or more of alkali-swellable polymers, urea solutions and polyurethane associates; and the inorganic thickener is selected from inorganic silicate solutions.

[0029] Furthermore, the water-based repair paint composition further comprises 1-5 parts of a surface additive, calculated by weight.

[0030] Further, the surface additive is selected from BYK-011, One or more of Foamex 805N, Surfynol 104A, Surfynol 104BC, Surfynol 440, BYK345.

[0031] Further, the water-based repair paint composition further comprises 3-10 parts of an organic solvent;

[0032] The organic solvent is selected from one or more of isoparaffin solvents, isooctyl alcohol, ethylene glycol hexyl ether, ethylene glycol isooctyl ether, isopropanol, n-pentanol, propylene glycol methyl ether, dipropylene glycol methyl ether and ethylene glycol butyl ether.

[0033] To achieve the above second purpose, the technical solution adopted by the present invention includes:

[0034] The present invention discloses a method for preparing the above-mentioned high-blackness water-based repair paint composition, comprising the following steps:

[0035] Mix water and water-based resin for primary dispersion, then add color paste for secondary dispersion, and finally add rheological additive and mix evenly to obtain the product.

[0036] To achieve the third objective, the technical solution adopted by the present invention includes:

[0037] The present invention discloses an application of the above-mentioned high-blackness water-based repair paint composition in the field of automobile repair.

[0038] To achieve the fourth objective, the technical solution adopted by the present invention includes:

[0039] The invention discloses an application of the high-blackness water-based repair paint composition in preparing a water-based paint product for automobile repair.

[0040] Beneficial effects of the present invention:

[0041] The present invention discloses a high-blackness water-based repair paint composition. In the present invention, a color paste with high blackness and good stability is obtained by preparing a suitable color paste formula and combining a high-energy grinding process, and then the color paste is added to a specific water-based resin system and combined with a selected rheological additive to finally obtain a high-blackness and high-stability water-based repair paint composition. The high-blackness and high-stability water-based repair paint composition can be heat-stored at 50°C for 3 months, and its fineness, viscosity, color difference and blackness will not change significantly. The stability is significantly higher than the level of similar repair paints disclosed in the prior art, and the water-based repair paint composition meets the environmental protection requirements for water-based paint in the industry, conforms to the popular trend of automobile colors, and better caters to future market demand. DETAILED DESCRIPTION

[0042] In order to explain the present invention more clearly, the present invention is further described below in conjunction with preferred embodiments. It should be clear that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] In addition, unless otherwise specified, the raw materials used in the present invention can be obtained commercially, and any range recorded in the present invention includes the end value and any numerical value between the end values ​​and any sub-range formed by the end value or any numerical value between the end values.

[0044] At present, in order to improve the ultimate blackness of the repair paint and achieve the ultimate effect equivalent to the original paint, technicians usually introduce high-pigment carbon black pigments when selecting color paste raw materials, combined with the control of pigment fineness, and finally present excellent coating effects. However, when high-pigment carbon black pigments are introduced, the original particle size of high-pigment carbon black itself is small, and it is difficult to achieve effective and stable dispersion, and it is difficult to fully reflect its high blackness advantage. Even if a relatively good nano-level dispersion is achieved at the beginning (that is, the fineness reaches D90≤200nm), high-pigment carbon black flocculation is very likely to occur, increasing the risk of the paint returning to coarseness, causing the paint to fluctuate in quality and hue during different storage cycles, seriously affecting the repair effect, especially water-based repair paint coatings are difficult to achieve a long-term shelf life of 2-4 years. Even if a wetting and dispersing agent commonly used in some fields is added, it can only promote the wetting of the pigment to a certain extent and improve its storage stability, but the storage stability is still difficult to meet the application requirements, and a certain degree of blackness is sacrificed. In order to obtain a high-blackness and high-stability repair paint, the present invention develops a water-based repair paint composition formula. When a suitable water-based resin, color paste and rheological additive are used together, a high-blackness and stable water-based repair paint composition can be obtained. The shelf life of the finished repair paint is 2-4 years, which solves the problem that the shelf life of existing similar products is only 3-6 months. The specific formula is:

[0045] By weight, the water-based repair paint composition comprises

[0046] 10-30 parts of a color paste as a coloring component, which contains at least one pigment that provides color and / or provides optical effects;

[0047] 20-45 parts of an aqueous resin as a film-forming component, which comprises at least one polyurethane dispersion;

[0048] 4-20 parts of a rheological additive for adjusting rheological properties, comprising at least one organic thickener and at least one inorganic thickener; and

[0049] 5-58 parts of water;

[0050] The pigment is high-color carbon black, accounting for 10-25% of the color paste mass, which is selected from Cabot 2000, 5000 III and Orion FW310.

[0051] In order to meet the high blackness requirement, high-pigment carbon black is introduced into the formula, wherein the initial average particle size of the high-pigment carbon black is ≤13nm, and nano-scale carbon black is conducive to obtaining better blackness. At the same time, in order to prevent carbon black from agglomerating, a medium- and low-molecular-weight (within 1000) wetting agent that can quickly reduce the dynamic surface tension is also introduced into the color paste formula, accounting for 1-5% of the total mass of the color paste raw material. The wetting agent can accelerate the wetting of the high-pigment carbon black, and a high-molecular-weight (above 10,000) dispersant is compounded, accounting for 20-59% of the total mass of the color paste raw material. The synergistic effect produced can significantly improve the wettability and dispersibility of the pigment particles, so that the color paste remains stable. Combined with a high-energy sand mill, the grinding efficiency is improved, and a nano black color paste with good stability can be effectively and quickly obtained.

[0052] Furthermore, in order to better maintain the stability of the water-based repair paint composition, a polyurethane dispersion with a small particle size and good pigment wettability is used to further stabilize the color paste when preparing the water-based repair paint composition, and then a suitable rheological additive system is used to finally achieve a long-term storage stability of 2-4 years for the water-based repair paint composition.

[0053] It should be noted that for technicians, although the ways to improve the blackness of the coating, improve the wettability and dispersibility of the pigment particles and the stability of the coating are clear, that is, introducing high-chroma pigments to improve the blackness of the coating, introducing high-performance wetting agents and dispersants to improve the wettability of the pigment particles and the dispersibility in the coating system, the differences are still large for the color pastes formed by different pigments and the introduction of color pastes into different coating systems. The properties of different pigments and different coating compositions will affect the state presented by the final coating. Based on the previously disclosed reports, it is not possible to fully provide sufficient reference for subsequent research. Therefore, the development of new color pastes and new coating systems still requires technicians to invest a lot of research and development efforts. For the high-pigment carbon black provided by the present invention, in order to prevent its secondary agglomeration and affect the overall stability of the coating, the present invention has finally determined to use a specific type of medium and low molecular weight wetting agent and a high molecular weight dispersant for matching through a large number of experimental screenings, which not only meets the blackness and stability requirements of the color paste, but also enables the water-based repair paint composition containing the color paste to meet the application requirements.

[0054] Further, the wetting agent is selected from one or more of Surfynol 104A, Surfynol 104BC, and Carbowet GA-210; the dispersant is selected from DISPERBYK-2014, DispexUltraPX4585, Solsperse TMOne or more of W210. The selection of medium and low molecular weight wetting agents has the ability to quickly reduce dynamic surface tension. When the zirconium beads hit the high-pigment carbon black at high speed during the high-energy sand mill grinding process, the wetting agent quickly reduces the dynamic surface tension, wets and coats the high-pigment carbon black, and also has a certain defoaming ability; while the high molecular weight dispersant has a pigment anchoring group, such as amine, carboxyl, phosphoric acid or phosphate, amide, carbamate, etc. At the same time, the polymer can provide good steric hindrance, thus having a good dispersing, deflocculating and stabilizing effect, so under the synergistic effect of the wetting agent and dispersant, a better grinding and dispersing effect can be achieved.

[0055] Further, in percentage by mass, the color paste also comprises

[0056] Defoaming agent 0.2-2%;

[0057] pH adjuster 0.2-2%;

[0058] The rest is water.

[0059] The color paste formula provided by the present invention does not contain resin, has higher concentration, better stability and blackness, and is suitable for the coating system provided by the present invention.

[0060] Furthermore, the defoaming agent is selected from one or more of Foamstar SI 2280, BYK-011, and BYK-024.

[0061] Furthermore, the pH regulator is selected from N,N-dimethylethylamine (DMEA) and / or Dow's AMP95, so that the pH value of the color paste is controlled at 7.5-8.5.

[0062] Furthermore, the D90 of the color paste is ≤200nm.

[0063] Furthermore, the polyurethane dispersion is selected from one or more of polycarbonate-modified polyurethane dispersion, aliphatic waterborne polyurethane dispersion, and aliphatic polycarbonate-type waterborne polyurethane dispersion.

[0064] Furthermore, the average particle size of the polyurethane dispersion is ≤60 nm.

[0065] In a specific embodiment, the polyurethane dispersion is selected from Covestro's UH2110 or The product of UH2648 / 1 and the model of Allnex Resin (China) are The product model of TW 6450 / 30WA is Lubrizol One or more of the products of 898 and HYDRAN WLS-210 produced by DIC Corporation.

[0066] In the present application, by selecting a waterborne polyurethane dispersion with a small particle size and a high molecular weight, the paint film can be endowed with excellent comprehensive properties, and at the same time, it also plays an auxiliary wetting and dispersing role on the color paste, thereby further effectively extending the storage time of the waterborne repair paint composition. In addition, since the particle size of the waterborne polyurethane dispersion selected in the present application is small, it has the characteristics of strong permeability, which reduces the color difference between the wet film and the dry film formed by the waterborne repair paint composition to a certain extent, and further improves the color matching efficiency at the construction site.

[0067] Of course, rheological additives that adjust rheological properties are equally important. Experiments have found that when organic thickeners and inorganic thickeners are used in combination, the organic and inorganic networks formed produce a synergistic effect, with better anti-settling properties making the coating more stable.

[0068] Further, the rheological additive comprises 0.5-5 parts of an organic thickener and 3-15 parts of an inorganic thickener; the organic thickener is selected from one or more of an alkali-swellable polymer, a urea solution and a polyurethane associate. For example, the alkali-swellable polymer can be selected from BASF (China) Co., Ltd. AS1130, BYK's model is AQUATIX 8421, etc.; the urea solution can be selected from BYK's RHEOBYK-7420ES; the polyurethane associate can be selected from San Nopco's NOPALL 3303.

[0069] Furthermore, the inorganic thickener is selected from an inorganic silicate solution, such as a LAPONITE-RD solution, and technicians can prepare the LAPONITE-RD solution by themselves. In terms of mass percentage, the LAPONITE-RD solution is composed of the following raw materials: 1-3% LAPONITE-RD (purchased from BYK Chemical), 1-6% polypropylene glycol 1000, and the balance is water.

[0070] Furthermore, the water-based repair paint composition further comprises a surface additive having defoaming and auxiliary wetting functions, which is 1-5 parts. For example, the surface additive can be a defoamer of BYK Chemical with a model number of BYK-011, and a defoamer of Evonik Industries with a model number of Foamex 805N defoamer, Surfynol 104A, Surfynol 104BC, Surfynol 440, BYK345 from BYK Chemical, etc.

[0071] Furthermore, the water-based repair paint composition also includes 3-10 parts of an organic solvent, which can be selected from one or more of an isoparaffin solvent, isooctyl alcohol, ethylene glycol hexyl ether, ethylene glycol isooctyl ether, isopropanol, n-pentanol, propylene glycol methyl ether, dipropylene glycol methyl ether and ethylene glycol butyl ether. The combination of the above organic solvents plays an important role in the defoaming, rheology and volatilization rate regulation of the water-based repair paint composition.

[0072] Furthermore, the water-based repair paint composition further comprises 0.2-1.0 parts of a pH adjuster, and the pH adjuster can be selected from DMEA and / or AMP95.

[0073] Furthermore, the water-based repair paint composition should ensure that the B6 viscosity is maintained at 500-2000mpa.s and the fineness is ≤10um when the preparation is completed and during the storage period (2-4 years), so as to meet the requirements of coating construction application.

[0074] According to the second aspect of the present application, the present invention also provides a method for preparing the water-based repair paint composition as described above, comprising the steps of preparing a color paste and obtaining the water-based repair paint composition, wherein the specific steps are:

[0075] 1) Preparation of color paste

[0076] Mix water, a wetting agent, a dispersant, a defoamer and a pH adjuster, perform a primary dispersion, and then add high-color carbon black for a secondary dispersion to obtain a premixed slurry;

[0077] Add the mixed liquid into a grinder and grind to obtain;

[0078] Wherein, the grinding conditions meet at least one of the following conditions:

[0079] i) the particle size of the grinding medium of the grinder is 0.3-1.0 mm;

[0080] ii) the filling rate of the grinding media of the grinding mill is 75-88%;

[0081] iii) the flow rate of the color paste is 100-200 kg / h;

[0082] iv) The grinding media are zirconium oxide beads or yttrium-modified zirconium beads.

[0083] 2) Preparation of water-based repair paint composition

[0084] Mix water, water-based resin, surface additives and organic solvents, perform primary dispersion, add the ground color paste, perform secondary dispersion, and finally add rheological additives to adjust the viscosity and pH adjusters to adjust the pH.

[0085] The invention will be further described below through specific examples.

[0086] Examples 1-3

[0087] The formula of the water-based repair paint composition provided in Examples 1-3 is shown in Table 1 below, and the formula of the color paste is shown in Table 2 below.

[0088] Table 1 Water-based repair paint composition formula of Examples 1-3

[0089]

[0090]

[0091] Wherein, the LAPONITE-RD solution used in Examples 1-3 is composed of 2wt% LAPONITE-RD, 94wt% deionized water and 4wt% polypropylene glycol 1000;

[0092] LAPONITE-RD was purchased from BYK Chemicals. LAPONITE-RD solution was prepared according to the following steps:

[0093] Add water at a high speed of 1000-1500r / min, then slowly add LAPONITE-RD, stir for 10-20 minutes, then add polypropylene glycol 1000, stir for 15-20 minutes.

[0094] Table 2 Color paste formula of Examples 1-3

[0095]

[0096] Based on the formulas in Table 1 and Table 2, the color paste and the water-based repair paint composition were prepared in the following specific steps:

[0097] (1) Preparation of the color paste

[0098] (1.a) According to the composition and content of the color paste in Table 2, deionized water, dispersant, wetting agent, defoaming agent, and pH adjuster are placed in a high-speed disperser and stirred at a speed of 300-500 r / min for 10 min;

[0099] (1.b) Then adjust the stirring speed to 500-750 r / min, slowly add high-color carbon black, and disperse at high speed at 1500-2500 r / min for 40-60 min to obtain a premixed slurry;

[0100] (1.c) The premixed slurry after high-speed dispersion is cyclically ground using a NETZSCH NEOS horizontal pin sand mill, the sand mill beads are zirconium oxide beads, the sand mill bead particle size is 0.3-1.0 mm, the sand mill bead filling rate is 75-88%, the flow rate of the premixed slurry is 100-200 kg / h; the grinding residence time is 30-50 min, and the product is obtained;

[0101] (2) Preparation of water-based repair paint composition

[0102] (2.a) According to the composition and content formula of the water-based repair paint composition in Table 1, add the water-based resin, deionized water, and surface additives into a low-speed disperser in sequence and stir at a speed of 200-300 r / min for 10 min;

[0103] (2.b) then slowly add the pre-mixed organic solvent at a speed of 300-500 r / min, disperse for 15-20 min, and then add the corresponding color paste obtained in step (1);

[0104] (2.c) Add LAPONITE-RD solution, and then add the remaining rheological additives to adjust the viscosity to B6 viscosity 500-1000mPa.s, and finally add pH adjuster to adjust the pH to 8.0-9.5.

[0105] Comparative Example 1

[0106] This comparative example provides a black repair paint composition, the formulation and preparation process of which refer to the scheme of Example 1, except that the Cabot 2000 replaced by Cabot 1300, and the rest is completely consistent with the solution of Example 1.

[0107] Comparative Example 2

[0108] This comparative example provides a black repair paint composition. The formula and preparation process are the same as those in Example 2, except that the dispersant DISPERBYK-2014 is replaced by TEGO 760W, and the rest is completely consistent with the scheme in Example 2.

[0109] Comparative Example 3

[0110] This comparative example provides a black repair paint composition, the formula and preparation process of which refer to the scheme of Example 3, the only difference is that no wetting agent is added to the color paste, and the rest is completely consistent with the scheme of Example 3.

[0111] Comparative Example 4

[0112] This comparative example provides a black repair paint composition. The formula and preparation process refer to the scheme of Example 1, the only difference is that the horizontal pin sand mill NETZSCH NEOS used for grinding the color paste is replaced by a non-pin horizontal sand mill NETZSCH LABSTAR for cyclic grinding, and the rest is exactly the same as the scheme of Example 1.

[0113] Comparative Example 5

[0114] This comparative example provides a black repair paint composition. The formula and preparation process refer to the scheme of Example 1, except that the rheological additive used does not contain LAPONITE-RD solution, and the amount thereof is supplemented with water. The rest is completely consistent with the scheme of Example 1.

[0115] Comparative Example 6

[0116] This comparative example provides a black repair paint composition, the formulation and preparation process of which refer to the scheme of Example 1, the only difference is that the rheological additive used does not contain an organic thickener, and the rest is completely consistent with the scheme of Example 1.

[0117] Comparative Example 7

[0118] This comparative example provides a black repair paint composition. The formula and preparation process refer to the scheme of Example 1, the only difference is that the content of the LAPONITE-RD solution used is 20 parts, and the rest is completely consistent with the scheme of Example 1.

[0119] Comparative Example 8

[0120] This comparative example provides a black repair paint composition, the formula and preparation process of which refer to the scheme of Example 1, the only difference is that the content of the organic thickener used is 6 parts, and the rest is completely consistent with the scheme of Example 1.

[0121] Comparative Example 9

[0122] This comparative example provides a black repair paint composition, the formula and preparation process of which refer to the scheme of Example 3, except that 20 parts of BASF (China) Co., Ltd. PU 1035W resin replaces 10 parts of TW 6450 / 30WA and 10 parts 898 resin, and the rest is completely consistent with the scheme of Example 3.

[0123] Performance Testing

[0124] During the grinding process of step (1), dynamic light scattering (DLS) was used to measure the particle size data of each color paste at different grinding residence times to obtain the particle size data shown in Table 3. The final grinding residence time was determined to be 30-50 min.

[0125] Table 3 Particle size data of color paste at different grinding residence time

[0126]

[0127] Furthermore, the viscosity and fineness of the water-based repair paint compositions of Examples 1-3 and Comparative Examples 1-9 were tested, and the color of the paint film was tested using a BYK mac-I five-angle colorimeter with a 150 μm scraper; after hot storage, the same test was performed, and the color difference was based on the initial color. The obtained data are shown in Table 4.

[0128] Table 4 Thermal storage stability data of waterborne repair paint composition

[0129]

[0130]

[0131] According to the results in Table 3 and Table 4, the water-based repair paint composition of each embodiment of the present invention has the advantages of high blackness and good stability; the carbon black selected in Comparative Example 1 is not black enough and is difficult to grind and disperse; the dispersant selected in Comparative Example 2 is not suitable, and it is difficult to form a stable nano-color paste, which ultimately affects the performance of the water-based repair paint composition; Comparative Example 3 does not have a wetting agent, the grinding efficiency is low, and the color paste particle size achieved is not good enough; the grinding equipment used in Comparative Example 4 has insufficient energy density and cannot achieve a good grinding particle size; Comparative Example 5 does not introduce LAPONITE-RD solution, and the body The compounding effect of organic thickener / inorganic thickener cannot be produced in the system, and the heat storage stability is insufficient; in Comparative Example 6, there is no organic thickener, the viscosity is too low, it is not suitable for coating construction application, it is easy to cause spray sagging, and the heat storage stability is also insufficient; in Comparative Example 7, the LAPONITE-RD solution content is too high, the viscosity of the water-based repair paint composition is high, and after heat storage, the viscosity increases seriously, the fluidity is poor, and the fineness deteriorates; in Comparative Example 8, the organic thickener content is too high, the viscosity of the water-based repair paint composition is too high, the fluidity is poor, the viscosity increases seriously after heat storage, and the fineness deteriorates.

[0132] In Comparative Example 9 PU 1035W resin has a small molecular weight and contains 1.1% of relatively large hydroxyl hydrophilic functional groups. When the repair paint system cannot be further cross-linked, it will have a certain negative impact on the performance of the paint film. The paint film has poor water resistance. After immersion at 40°C for 10 days, the surface is severely blistered. The water resistance of the paint film cannot meet the requirements of the repair paint industry, and the thermal storage stability is also poor.

[0133] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A water-based repair paint composition, characterized in that By weight, the water-based repair paint composition comprises 10-30 parts of a color paste as a coloring component, which contains at least one pigment that provides color and / or provides optical effects; 20-45 parts of an aqueous resin as a film-forming component, which comprises at least one polyurethane dispersion; 4-20 parts of a rheological additive for adjusting rheological properties, comprising at least one organic thickener and at least one inorganic thickener; and 5-58 parts of water; Wherein, the pigment is high-color carbon black, accounting for 10-25% of the mass of the color paste, which is selected from 2000, 5000 III and Orion FW310.

2. The water-based repair paint composition according to claim 1, characterized in that By mass percentage, the color paste also comprises Wetting agent 1-5%; Dispersant 20-59%; Defoaming agent 0.2-2%; pH adjuster 0.2-2%; The rest is water; Preferably, the D90 of the color paste is ≤200nm.

3. The water-based repair paint composition according to claim 2, characterized in that The wetting agent is selected from one or more of Surfynol 104A, Surfynol 104BC, and Carbowet GA-210; Preferably, the dispersant is selected from DISPERBYK-2014, DispexUltraPX4585, Solsperse TM One or more of W210; Preferably, the defoaming agent is selected from one or more of Foamstar SI 2280, BYK-011, and BYK-024.

4. The water-based repair paint composition according to claim 1, characterized in that The polyurethane dispersion is selected from one or more of polycarbonate-modified polyurethane dispersion, aliphatic waterborne polyurethane dispersion, and aliphatic polycarbonate-type waterborne polyurethane dispersion; Preferably, the average particle size of the polyurethane dispersion is ≤60 nm.

5. The water-based repair paint composition according to claim 1, characterized in that The rheological additive comprises 0.5-5 parts of an organic thickener and 3-15 parts of an inorganic thickener; The organic thickener is selected from one or more of alkali-swellable polymers, urea solutions and polyurethane associates; and the inorganic thickener is selected from inorganic silicate solutions.

6. The water-based repair paint composition according to claim 1, characterized in that The water-based repair paint composition further comprises 1-5 parts of a surface additive by weight; Preferably, the surface additive is selected from BYK-011, One or more of Foamex 805N, Surfynol 104A, Surfynol 104BC, Surfynol 440, BYK345.

7. The water-based repair paint composition according to claim 1, characterized in that The water-based repair paint composition further comprises 3-10 parts of an organic solvent; The organic solvent is selected from one or more of isoparaffin solvents, isooctyl alcohol, ethylene glycol hexyl ether, ethylene glycol isooctyl ether, isopropanol, n-pentanol, propylene glycol methyl ether, dipropylene glycol methyl ether and ethylene glycol butyl ether.

8. A method for preparing a water-based repair paint composition as described in any one of claims 1 to 7, characterized in that: The steps include: Mix water and water-based resin for primary dispersion, then add color paste for secondary dispersion, and finally add rheological additive and mix evenly to obtain the product.

9. Use of the water-based repair paint composition according to any one of claims 1 to 7 in the field of automobile repair.

10. Use of the water-based repair paint composition according to any one of claims 1 to 7 in preparing a water-based paint product for automobile repair.

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