Coating system
By using a coating system composed of a first coating with a high FI value and a second coating of a specific pigment in automotive coatings, the shortcomings of existing coatings in appearance and mechanical properties are solved, and stable color effects and good mechanical properties are achieved.
Patent Information
- Application Number
- CN202410203499.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-23
- Publication Date
- 2025-08-26
AI Technical Summary
Existing automotive coatings are difficult to provide excellent and stable appearance, while taking into account both mechanical and environmental requirements, especially in terms of color stability and mechanical properties.
Using a coating system consisting of a first coating and a second coating, the first coating has a high FI value, and the second coating contains pigments of a specific refractive index film layer, applied by wet and cured at 80-140°C to form a coating effect with a bright color background and a change in color with angle.
It achieves excellent appearance effect, provides three-dimensional layering and color stability, while not appearing rough, is suitable for color control of different batches of substrates, and has good mechanical properties.
Abstract
Description
Technical Field
[0001] The present invention relates to the field of coatings, in particular to a coating system, in particular to a coating system applied to automobiles. Background Art
[0002] A car's exterior color is a key factor in determining purchase decisions. To attract customers, automakers favor coatings that impart dazzling, stable colors to their vehicles. Therefore, developing automotive coatings that offer excellent, stable appearance while also balancing mechanical performance and environmental performance is of practical significance and holds great promise. Summary of the Invention
[0003] The present inventors have conducted extensive research to develop a coating system that can be applied to automotive substrates and provide an excellent and stable appearance.
[0004] The present invention provides a coating system comprising a first coating layer and a second coating layer, wherein the first coating layer is formed from a first coating composition, and the second coating layer is formed from a second coating composition, wherein the first coating layer has an FI value of 15 or higher, and the second coating composition comprises a pigment, wherein the pigment comprises a substrate covering a high-refractive-index film layer and a low-refractive-index film layer, wherein the refractive index of the high-refractive-index film layer is greater than 1.65, and the refractive index of the low-refractive-index film layer is less than or equal to 1.65.
[0005] The present invention also provides a coated substrate, comprising a substrate and the coating system coated on at least a portion of the substrate.
[0006] The features and advantages of the present invention will be more particularly presented in the following detailed description of the embodiments. DETAILED DESCRIPTION
[0007] In this application, unless expressly stated otherwise, the use of the singular includes the plural and the plural includes the singular. For example, although "a" pigment is mentioned herein, one or more of the pigment may be used.
[0008] Throughout this application, the terms "comprise," "include," and "contain" are not intended to limit the invention to exclude any variations or additions. Furthermore, although the present invention has described coating compositions, methods of preparation, and the like using terms such as "comprising," the coating compositions, methods of preparation, and the like described herein may also be described as "consisting essentially of" or "consisting of." In this context, "consisting essentially of" means that any additional ingredients do not materially affect the properties of the coating formed from the coating composition.
[0009] In this application, unless otherwise expressly stated, the use of "or" means "and / or", even though "and / or" may be explicitly used in certain circumstances. In addition, it should be understood that any numerical range listed herein is intended to include all subranges contained therein. For example, a range of "1 to 10" is intended to include all subranges between the recited minimum value of 1 and the recited maximum value of 10 (inclusive), that is, all subranges having a minimum value equal to or greater than 1 and a maximum value equal to or less than 10.
[0010] Except in the examples or where otherwise explicitly stated, all numerical values used in the specification and claims, such as those representing quantities of ingredients, should be interpreted as varying in all instances according to the term "about." Therefore, unless otherwise indicated, the numerical parameters listed in the following specification and claims are approximate and may vary depending on the desired properties of the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be interpreted in terms of significant figures and subject to ordinary rounding.
[0011] Although the numerical ranges and parameters setting forth the broad scope of the invention are approximate, the numerical values set forth in the specific examples are reported as accurately as possible. However, any numerical value inherently has certain errors which are the inevitable result of the standard deviation obtained in its respective measurement methods.
[0012] The present invention relates to a coating system comprising a first coating layer and a second coating layer, wherein the first coating layer is formed from a first coating composition, and the second coating layer is formed from a second coating composition, wherein the first coating layer has an FI value of 15 or higher, and the second coating composition comprises a pigment, wherein the pigment comprises a substrate covering a high-refractive-index film layer and a low-refractive-index film layer, wherein the refractive index of the high-refractive-index film layer is greater than 1.65, and the refractive index of the low-refractive-index film layer is less than or equal to 1.65.
[0013] In the coating system according to the present invention, a first coating layer with a specific high FI value and a second coating layer containing a specific pigment work together to achieve an excellent appearance. The high FI value first coating layer provides a bright color background and a higher shimmering characteristic, while the second coating layer containing the specific pigment provides a color that changes with angle. Visually, this coating system produces a noticeable purple-to-green-blue effect, and the color texture maintains a three-dimensional sense of depth and shimmer without appearing rough. Furthermore, this coating system provides color stability, making it easy to control the color of different substrate batches.
[0014] In the coating system according to the present invention, the first coating layer is closer to the substrate than the second coating layer, and no other coating layer is contained between the first coating layer and the second coating layer. Suitably, other coating layers may be included between the first coating layer and the substrate. Suitably, other coating layers may be included in addition to the second coating layer (away from the substrate). For example, a clear coat layer may be included in addition to the second coating layer.
[0015] In the coating system according to the present invention, the first coating layer and the second coating layer can be applied wet-on-wet. That is, the first coating layer and the second coating layer are cured simultaneously to form films, and the first coating layer is not cured before the second coating composition is applied. The term "cured" means that at least a portion of the components of the coating composition are polymerized and / or cross-linked, or dried to form a hardened coating film.
[0016] The first coating layer and the second coating layer can be cured by heating. The first coating composition and the second coating composition can be cured at a temperature of 80 to 140° C. Therefore, the first coating composition and the second coating composition can be low-temperature curing systems or high-temperature curing systems.
[0017] Herein, the FI value refers to the color flop index, which is related to the color brightness at each angle. The larger the FI value, the greater the difference between small and large angles, and the closer the color is to a mirror effect. In this context, the FI value can be calculated using the following formula by measuring the brightness (L) at 15°, 45°, and 110° using a commercially available BYK colorimeter.
[0018] FI=2.69*(L* 15° -L* 110° ) 1.11 / (L* 45° ) 0.86
[0019] The first coating layer has an FI value of 15 or higher. Suitably, the first coating layer may have an FI value of 15 to 24. For example, the first coating layer may have an FI value of 16, 17, 18, 19, 20, 21, 22 or 23.
[0020] The first coating composition forming the first coating layer may include coated aluminum powder for waterborne systems and / or non-coated aluminum powder for automotive paints that has undergone a passivation treatment. The specific type of aluminum powder, combined with the targeted aluminum powder formulation in the coating composition and a proper spray application method, provides a high FI value.
[0021] Suitably, the first coating layer may have a G value of 6 or higher. For example, the first coating layer may have a G value of 6.5, 7, 7.5, 8, 8.5, 9, or 9.5. The "G value" refers to the scintillation of the coating, which indicates the scintillation intensity of the color under the light source. The smaller the G value, the lower the scintillation intensity, and the closer the color is to a delicate mirror effect. In this article, the G value can be obtained by testing with a commercially available BYK colorimeter.
[0022] Suitably, the first coating layer may have a dry film thickness of 8 to 18 microns. The "dry film thickness" refers to the thickness of the coating layer after it is fully cured. For example, the first coating layer may have a dry film thickness of 9, 10, 11, 12, 13, 14, 15, 16, or 17 microns.
[0023] The first coating layer may be formed from a first aqueous coating composition. In this context, the term "aqueous" means that the solvent of the coating composition contains at least 50 wt% of water.
[0024] The second coating composition comprises a special effect pigment, the pigment comprising a substrate covering a high refractive index film layer and a low refractive index film layer, wherein the refractive index of the high refractive index film layer is greater than 1.65 and the refractive index of the low refractive index film layer is less than or equal to 1.65. Suitably, the pigment may comprise at least two high refractive index film layers and at least two low refractive index film layers, the high refractive index film layers and the low refractive index film layers being arranged alternately. For example, the pigment may comprise 3, 5, 7 or 9 high refractive index film layers and 3, 5, 7 or 9 low refractive index film layers. Suitably, the thickness of each film layer in the high refractive index film layer is 10-400 nm. Suitably, the thickness of each film layer in the low refractive index film layer is 10-700 nm.
[0025] Based on the total weight of the second coating composition, the pigment may be present in an amount of 0.3 wt% or more, suitably 0.5 wt% or more, such as 1 wt% or more, and / or 5 wt% or less, suitably 4 wt% or less, such as 3 wt% or less. Suitably, the pigment may be present in an amount of 0.3 to 5 wt%, suitably 0.5 to 4 wt%, 1 to 3 wt%, or any range between the above values, based on the total weight of the second coating composition.
[0026] Suitably, the second coating composition may further comprise one or more other pigments. The other pigments are different from the pigments covering the high refractive index film layer and the low refractive index film layer. The other pigments may comprise organic pigments, inorganic pigments and / or effect pigments. If present, the sum of the content of the other pigments and the pigments covering the high refractive index film layer and the low refractive index film layer is no more than 5 wt %, i.e., less than or equal to 5 wt % of the total weight of the second coating composition.
[0027] The content of pigment (the pigment covering the high-refractive index film layer and the low-refractive index film layer, and one or more other pigments) in the second coating composition can also be expressed as a pigment-to-binder ratio. The "pigment-to-binder ratio (P / B)" refers to the weight ratio of the pigment in the second coating composition to the solids weight of the binder in the second coating composition. Suitably, the second coating composition has a pigment-to-binder ratio of 0.1 to 0.4.
[0028] Suitably, the second coating formed by the second coating composition may have a dry film thickness of 5 to 15 microns. For example, the second coating may have a dry film thickness of 6, 7, 8, 9, 10, 11, 12, 13 or 14 microns.
[0029] In the coating system according to the present invention, the first coating and the second coating cooperate to bring about an excellent appearance. For example, the coating system according to the present invention may have an L(15) greater than 100, an L(75) of 15 to 25, and / or an L(110) of 15 to 25. The L(15), L(75), and L(110) represent the L values (brightness values) at angles of 15 degrees, 75 degrees, and 110 degrees, respectively. The L values are chromatic values based on the CIELAB color difference theory, which can be obtained by measuring with a colorimeter. Suitably, the a(-15) and a(45) of the coating system differ by at least 2 units. The a(-15) and a(45) represent the a values at angles of -15 degrees and 45 degrees, respectively. The a values are chromatic values based on the CIELAB color difference theory, which can be obtained by measuring with a colorimeter. Suitably, the b(-15) and b(45) of the coating system differ by at least 15 units. The b(-15) and b(45) represent the b values at -15 and 45 degrees, respectively, and the b values are chromaticity values based on the CIELAB color difference theory, which can be measured by a colorimeter. The coating system according to the present invention can provide an FI value of 12 or higher.
[0030] The present invention also provides a coated substrate comprising a substrate and the above-mentioned coating system applied to at least a portion of the substrate. In this context, the coating can be achieved by methods known in the art, including but not limited to spraying, dipping, roller coating, brushing, etc. The substrate can comprise a metal and / or plastic substrate. For example, the substrate can comprise steel, aluminum, polypropylene, carbon fiber, and / or a nylon substrate. Suitably, the substrate is part of a vehicle.
[0031] While particular aspects of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various other changes and modifications may be made without departing from the spirit and scope of the invention. It is therefore intended that the appended claims cover all such changes and modifications as fall within the scope of the invention.
Claims
1. A coating system comprising a first coating layer and a second coating layer, wherein the first coating layer is formed from a first coating composition, and the second coating layer is formed from a second coating composition, wherein the first coating layer has an FI value of 15 or higher, and the second coating composition comprises a pigment, wherein the pigment comprises a substrate covering a high refractive index film layer and a low refractive index film layer, wherein the refractive index of the high refractive index film layer is greater than 1.65, and the refractive index of the low refractive index film layer is less than or equal to 1.
65.
2. The coating system of claim 1, wherein the first coating has an FI value of 15 to 24.
3. The coating system of claim 1 or 2, wherein the pigment comprises at least two high refractive index film layers and at least two low refractive index film layers.
4. The coating system of claim 3, wherein the high refractive index film layers and the low refractive index film layers are arranged alternately.
5. The coating system according to any one of claims 1 to 4, wherein the thickness of each of the high refractive index film layers is 10-400 nm, and the thickness of each of the low refractive index film layers is 10-700 nm.
6. The coating system of any one of claims 1-5, wherein the first coating has a G value of 6 or higher.
7. The coating system of any one of claims 1 to 6, comprising 0.3 to 5 wt% of pigment based on the total weight of the second coating composition.
8. The coating system of any one of claims 1 to 7, wherein the first coating has a dry film thickness of 8 to 18 microns, and the second coating has a dry film thickness of 5 to 15 microns.
9. The coating system of any one of claims 1 to 8, wherein the coating system provides a coating film brightness of L(15) greater than 100, L(75) between 15 and 25, and / or L(110) between 15 and 25.
10. The coating system of any one of claims 1-9, wherein the coating system provides an FI value of 12 or higher.
11. The coating system of any one of claims 1 to 10, wherein the coating system provides a difference between a(-15) and a(45) of at least 2 units, and / or a difference between b(-15) and b(45) of at least 15 units.
12. The coating system of any one of claims 1 to 11, wherein the first coating composition and the second coating composition are both water-borne.
13. The coating system of any one of claims 1-12, wherein the first coating composition and the second coating composition are applied wet-on-wet.
14. A coated substrate comprising a substrate and the coating system according to any one of claims 1 to 13 applied to at least a portion of the substrate.
15. The coated substrate of claim 14, wherein the substrate comprises a metal and / or plastic substrate.
16. The coated substrate of claim 14 or 15, wherein the substrate is part of a vehicle.