Metallic coating system

Abstract

Provided herein is a method of applying a metallic coating system comprising the steps of: 1) applying at least one undercoat layer to at least one substrate; and 2) coating the undercoat layer with at least one metallic basecoat. At least one metallic basecoat may comprise at least one metallic pigment in an acrylic dispersion, wherein at least one metallic pigment is a PVD pigment. Also described is an article comprising the metallic coating system coating disclosed herein.

Description

METALLIC COATING SYSTEMFIELD

[0001] The present disclosure relates generally to is a method of applying a metallic coating system comprising the steps of: 1) applying at least one undercoat layer to at least one substrate; and 2) coating the undercoat layer with at least one metallic basecoat. At least one waterborne metallic basecoat may comprise at least one metallic pigment in an acrylic dispersion, wherein at least one metallic pigment is a PVD pigment. At least one solventborne metallic basecoat may comprise at least one metallic pigment in an acrylic resin solution, wherein at least one metallic pigment is a PVD pigment. An article comprising the metallic coating system coating disclosed herein is also described.BACKGROUND

[0002] Metallic coatings have long been a popular option in automobiles, motorcycles, bicycles, and other vehicles. They have also been used in other applications like rims, glasses, watches, mobile phones, electronics, household utensils, and automotive interiors and accessories for cars such as door handles. A typical metallic coatings system is normally applied in multiple layers including a primer layer, a metallic basecoat layer, and a clearcoat layer. These conventional metallic coatings systems may often contain additional layers such as an undercoat and a leveling coat.

[0003] In particular, a silver metallic color is gaining popularity for metallic coatings. Qualities like brilliance, lightness, hiding power, and strong flop (as measured by the flop index, a measure of the change in lightness of a metallic color as it is tilted through the entire range of viewing angles, where metallic coatings provide a higher flop index and described in the Test Results section), or two-tone effect (angle dependent lightness of an application) combined with perfect non-leafing behavior, essentially mirror-like, are desired by customers. Although conventional metallic pigments such as silver dollar or cornflake types impart sparkle, they do not provide depth and a mirror-like appearance. Innovation in aluminum flake pigment development made it possible to achieve unique metallic appearances with high brilliance and chrome effect by using very thin metallic pigments known as PVD (physical vapor deposition) or VMF (vacuummetallized flakes) pigments. Due to the low layer thickness of PVD pigments, they can lay flat on the substrate and reflect light, so the color looks lighter / darker when viewed from different angles and imparts low sparkle. More recently, PVD (Physical Vapor Deposition) aluminum pigments have been growing in interesting as a preferred silver color for automotive exterior coatings. Generally, aluminum pigments currently produced by ball-milling present higher particle size and thicknesses, thus lowering brilliance and reflective power. However, special methods of manufacturing may produce aluminum pigment particles with sizes of about 10-12 pm and with extremely small thickness (30-50 nm). The sum of these two characteristics, small particle size and thickness, may impart a specific mirror-like or chrome-like effect with high brilliance and superior image reflection that is highly desired in premium automotive finishes.

[0004] Although the mirror-like appearance depends on the structure of the PVD pigment particles, the smoothness of the underlying substrate also plays a role. Specifically, the high mobility and small particles dimension cause metallic pigments, including PVD metallic pigments, to be influenced by the substrate smoothness. Rough surfaces can create local defects on the thin aluminum layer that eventually become distinctly on the substrate. For example, these visual defects may result an undesirable “orange peel” effect. Thus, is of pivotal importance to have the substrate smooth and defect-free before a coating is applied.

[0005] However, the currently available application methods for coatings containing PVD or VMF pigments metallic are time consuming and complicated. In order to achieve the intended appearance of metallic coatings containing PVD or VMF pigments, the right application method and layer build up is important. Since the PVD and VMF pigments orient according to the substrate, the surface of the substrate must be smooth and without any defects. Therefore, for automotive coatings the substrate must be sanded with very fine grits. In some cases, it is also advised to apply a leveling binder or clearcoat. Furthermore, the metallic basecoat containing PVD or VMF pigments should be applied in multiple thin layers.

[0006] Further, achieving higher flop index and lower graininess value, remains difficult in metallic coatings, especially with refinishing applications. In view of these challenges with conventional metallic coatings, including metallic coatings containing PVD or VMF pigments, the need therefore remains for coatings with improved application process that is faster and simpler than the currently available solutions in the market.BRIEF DESCRIPTION OF THE FIGURES

[0007] The preferred embodiment of which will be described in detail in the specification and illustrated in the accompanying drawings which form a part hereof, and wherein:

[0008] FIG. 1 illustrates a conventional metallic coating system.

[0009] FIG. 2 illustrates one option for a conventional metallic coating system with PVD metallic pigments.

[0010] FIG. 3 illustrates a second option for a conventional metallic coating system with PVD metallic pigments.

[0011] FIG. 4 illustrates the metallic coating system claimed and described herein.

[0012] FIG. 5 illustrates an exemplary application of the method described herein.SUMMARY

[0013] The embodiments of what is described herein are not intended to be exhaustive or to limit what is provided in the claimed subject matter and disclosed in the detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may appreciate and understand the principles and practices of what is provided in the claimed subject matter.

[0014] A method of applying a metallic coating system comprising the steps of: 1) applying at least one undercoat layer to at least one substrate; and 2) coating the undercoat layer with at least one metallic basecoat. At least one undercoat layer must be of a particular color as its shade and hue can have a major influence on the basecoat appearance. At least one undercoat layer may comprise a pigmented dispersion, and the pigmented dispersion may comprise at least one acrylic. Further, at least one undercoat layer may be mixed with at least one reducer prior to application. After the undercoat layer dries, the metallic basecoat, namely the PVD metallic basecoat, is applied in layers of a certain thickness, with flash-off between each application. The PVD metallic basecoat layer can typically range from about 6 microns to 8 microns thick for each layer (for a total basecoat thickness of about 30 to 40 microns after multiple coats have been applied), whereas typically toners used in metallic coatings systems are about 10 microns to 12 microns thick. In one embodiment, at least one waterborne metallic basecoat may comprise at least one metallic pigmentin an acrylic dispersion, and at least one metallic pigment is a PVD pigment. Tn another embodiment, at least one solventbome metallic basecoat may comprise at least one metallic pigment in an acrylic resin solution, wherein at least one metallic pigment is a PVD pigment. After the PVD basecoat is applied, at least one topcoat may be applied. The topcoat can typically range from about 6 microns to 8 microns thick. At least one clearcoat layer may then be applied to the topcoat. The total clearcoat layer may range from about 50 to 80 microns, where it is applied in more than one layer and each layer being about 25 to 40 microns thick. The method described may further comprise applying at least one dropcoat layer at an angle / di agonal to substantially bisect at least one metallic basecoat.

[0015] An article comprising the metallic coating system coating disclosed herein is also described.

[0016] To the accomplishment of the foregoing and related ends, the following description set forth certain illustrative aspects and implementations. These are indicative of but a few of the several ways in which one or more aspects may be employed. Other aspects, advantages and novel features of the disclosure will become apparent from the following detailed description when considered.DETAILED DESCRIPTION

[0017] Aspects of what is described herein are disclosed in the following description related to specific embodiments. Alternative embodiments may be devised without departing from the scope of what is described herein. Additionally, well-known embodiments of what is described herein may not be described in detail or will be omitted so as to not obscure the relevant details of what is described herein. Further, to facilitate an understanding of the description, discussion of several terms used herein follows.

[0018] As used herein, the word “exemplary” means “serving as an example, instance, or illustration.” The embodiments described herein are not limiting, but rather exemplary only. It should be understood that the described embodiments are not necessarily to be construed as preferred or advantageous over other embodiments. Moreover, the term “embodiment(s)” does not require that all embodiments include the discussed feature, advantage, or mode of operation.

[0019] The present disclosure relates generally to coatings systems that provide advantageous improvements over current coatings, specifically metallic coatings. It has been discovered that a method of applying a metallic coating system comprising the steps of 1) applying at least one undercoat layer to at least one substrate; and 2) coating the undercoat layer with at least one metallic basecoat can surprisingly lead to improved visual appearance, specifically flop index, color matching with reference colors, and graininess, over other metallic coatings, as well as other advantages.

[0020] In many embodiments, a method of applying a metallic coating system comprising the steps of 1) applying at least one undercoat layer to at least one substrate; and 2) coating the undercoat layer with at least one metallic basecoat. While currently available solutions require multilayer system with at least six layers of different coatings and typically the addition of components like hardeners, the method described herein only requires up to four layers of coating. The entire process thus becomes faster and simpler with the application method described. Further, this method described herein may be used during manufacturing of original equipment (OEM) or in aftermarket application such a refmish or collision repair and provides a more efficient method of application. Drawing details for the method for application are provided in FIG. 4 and FIG. 5.

[0021] In many embodiments, the method described herein may use spray application techniques. In one embodiment, the method described herein may use an HVLP (high volume low pressure) spray gun or similar applicator. Other application methods are also contemplated.

[0022] In many embodiments, at least one substrate wherein the substrate comprises wood, metal, glass, plastic, paper, leather, fabric, ceramic, concrete, cement, or any combination thereof. Other substrates are also contemplated.

[0023] In many embodiments, at least one undercoat layer may comprise a pigmented dispersion, and the pigmented dispersion may comprise at least one acrylic. In other embodiments, the acrylic may be an acrylic emulsion. In many embodiments, at least one acrylic has a temperature of glass transition (Tg) of about -10 °C to about 40 °C. The Tg described herein is measured by Differential Scanning Calorimetry (DSC) using ASTM D6604-00.

[0024] In some embodiments, the acrylic may be formed from alkyl (meth)acrylates and vinyl monomers, such as but not limited to, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n- / i- / t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl(meth)acrylate, glycidyl methacrylate, 4-hydroxybutyl acrylate glycidyl ether, 2- (acetoacetoxy)ethyl methacrylate, lauryl methacrylate, stearyl methacrylate, cyclohexyl methacrylate, diacetone acrylamide, acrylamide, methacrylamide, methylol (meth)acrylamide, styrene, a-methyl styrene, vinyl toluene, vinyl acetate, vinyl propionate, allyl methacrylate, or combinations thereof. In some embodiments, the alkyl methacrylate polymers may be those prepared from a range of C12 to C22 alkyl methacrylates. Some preferred monomers include styrene, methyl methacrylate, methacrylic acid, hydroxyethyl acrylate, acetoacetoxyethyl methacrylate, butyl acrylate, butyl methacrylate, or combinations thereof. Others are also contemplated.

[0025] In some embodiments, the acrylic may be modified with another technology such as silicone, epoxy, polyurethane, and combinations thereof. In many embodiments, the acrylic may comprise 25% to 70% by weight of the undercoat layer. In other embodiments, the acrylic can, for example, range from about 25% to about 65%, about 25% to about 60%, about 25% to about 55%, about 25% to about 50%, about 25% to about 45%, about 25% to about 40%, about 25% to about 35%, about 30% to about 70%, about 30% to about 65%, about 30% to about 60%, about 30% to about 55%, about 30% to about 50%, about 30% to about 45%, about 30% to about 40%, about 30% to about 35%, about 35% to about 70%, about 35% to about 65%, about 35% to about 60%, about 35% to about 55%, about 35% to about 50%, about 35% to about 45%, about 35% to about 40%, about 40% to about 70%, about 40% to about 65%, about 40% to about 60%, about 40% to about 55%, about 40% to about %50%, about 40% to about 45%, about 45% to about 70%, about 45% to about 65%, about 45% to about 60%, about 45% to about 55%, about 45% to about 50%, about 50% to about 70%, about 50% to about 65%, about 50% to about 60%, about 50% to about 55%, about 55% to about 70%, about 55% to about 65%, about 55% to about 60%, about 60% to about 70%, and about 60% to about 65%. Other ranges are also contemplated. In many embodiments, the pigmented dispersion also comprises at least one pigment. In some embodiments, the pigment may comprise organic pigments, inorganic pigments, or combinations thereof. In one embodiment, at least one pigment may comprise a special effects pigment such as pearlescent pigments, glass pigments, metallic pigments, or combinations thereof. In some embodiments, at least one pigment may comprise titanium dioxide, mica, various color pigments, or combinations thereof.

[0026] In many embodiments, at least one undercoat may be mixed with at least one reducer prior to application to the substrate. In many embodiments, at least one undercoat layer is reduced at least 10% prior to coating the substrate. In other embodiments, least one undercoat layer is reduced at least 20% prior to coating the substrate. In yet other embodiments, least one undercoat layer is reduced at least 30% prior to coating the substrate. In another embodiment, least one undercoat layer is reduced at least 40% prior to coating the substrate. In yet another embodiment, least one undercoat layer is reduced at least 50% prior to coating the substrate. In several embodiments, at least one undercoat layer is mixed with at least one reducer in a 1 :1 to 2: 1 ratio prior to coating the substrate. In one embodiment, at least one undercoat layer is mixed with at least one reducer in a 1 :1 ratio. In one embodiment, at least one undercoat layer is mixed with at least one reducer in a 2: 1 ratio. In many embodiments, the reducer comprises at least one ketone. At least one ketone may comprise methyl isobutyl ketone, methyl isoamyl ketone, methyl propyl ketone, methyl n-Amyl Ketone (MAK), or combinations thereof. Other ketones are also contemplated. At least one undercoat layer may be reduced by any type of reducer (also known as a thinner). Reducers thin the paint to help to help flow and leveling properties and provide an improved appearance. A reducer may be a urethane, a solvent, an epoxy, an acrylic, a polyester, or combinations thereof. Other types of reducers are contemplated.

[0027] Further, the second step of the method described herein is coating the undercoat layer with at least one metallic basecoat. In many embodiments, at least one metallic basecoat comprises at least one metallic pigment in an acrylic dispersion or an acrylic resin solution. In many embodiments, at least one acrylic dispersion or an acrylic resin solution has a temperature of glass transition (Tg) of about -10 °C to about 40 °C. The Tg described herein is measured by Differential Scanning Calorimetry (DSC) using ASTM D6604-00. In many embodiments, the acrylic can, for example, range from a Tg of about -10 °C to about 35 °C, from a Tg of about -10 °C to about 30 °C, from a Tg of about -10 °C to about 25 °C, from a Tg of about -10 °C to about 20 °C, from a Tg of about -10 °C to about 15 °C, from a Tg of about 0 °C to about 40 °C, from a Tg of about 0 °C to about 35 °C, from a Tg of about 0 °C to about 30 °C, from a Tg of about 0 °C to about 25 °C, from a Tg of about 0 °C to about 20 °C, from a Tg of about 0 °C to about 15 °C, from a Tg of about 0 °C to about 10 °C, from a Tg of about 10 °C to about 40 °C, from a Tg of about 10 °C to about 35 °C, from a Tg of about 10 °C to about 30 °C, from a Tg of about 10 °C to about 25 °C, from a Tg of about 10 °C to about 20 °C, from a Tg of about 15 °C to about 40 °C, from a Tg ofabout 15 °C to about 35 °C, from a Tg of about 1 °C to about 30 °C, from a Tg of about 15 °C to about 25 °C, from a Tg of about 20 °C to about 40 °C, from a Tg of about 20 °C to about 35 °C, from a Tg of about 20 °C to about 30 °C, from a Tg of about 25 °C to about 40 °C, from a Tg of about 25 °C to about 35 °C, and from a Tg of about 30 °C to about 40 °C. Other Tg ranges are also contemplated.

[0028] In some embodiments, the acrylic may be formed from alkyl (meth)acrylates and vinyl monomers, such as but not limited to, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n- / i- / t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, glycidyl methacrylate, 4-hydroxybutyl acrylate glycidyl ether, 2- (acetoacetoxy)ethyl methacrylate, lauryl methacrylate, stearyl methacrylate, cyclohexyl methacrylate, diacetone acrylamide, acrylamide, methacrylamide, methylol (meth)acrylamide, styrene, a-methyl styrene, vinyl toluene, vinyl acetate, vinyl propionate, allyl methacrylate, or combinations thereof. In some embodiments, the alkyl methacrylate polymers may be those prepared from a range of C12 to C22 alkyl methacrylates. Some preferred monomers include styrene, methyl methacrylate, methacrylic acid, hydroxyethyl acrylate, acetoacetoxyethyl methacrylate, butyl acrylate, butyl methacrylate, or combinations thereof. Others are also contemplated.

[0029] In some embodiments, the acrylic may be modified with another technology such as silicone, epoxy, polyurethane, and combinations thereof.

[0030] In many embodiments, the acrylic may comprise 30% to 70% by weight of the undercoat layer. In other embodiments, the acrylic can, for example, range from about 25% to about 65%, about 25% to about 60%, about 25% to about 55%, about 25% to about 50%, about 25% to about 45%, about 25% to about 40%, about 25% to about 35%, about 30% to about 70%, about 30% to about 65%, about 30% to about 60%, about 30% to about 55%, about 30% to about 50%, about 30% to about 45%, about 30% to about 40%, about 30% to about 35%, about 35% to about 70%, about 35% to about 65%, about 35% to about 60%, about 35% to about 55%, about 35% to about 50%, about 35% to about 45%, about 35% to about 40%, about 40% to about 70%, about 40% to about 65%, about 40% to about 60%, about 40% to about 55%, about 40% to about %50%, about 40% to about 45%, about 45% to about 70%, about 45% to about 65%, about 45% to about 60%, about 45% to about 55%, about 45% to about 50%, about 50% to about 70%, about50% to about 65%, about 50% to about 60%, about 50% to about 55%, about 55% to about 70%, about 55% to about 65%, about 55% to about 60%, about 60% to about 70%, and about 60% to about 65%. Other ranges are also contemplated.

[0031] In some embodiments, at least one metallic pigment is a PVD pigment. In another embodiment, at least one metallic pigment is a VMF pigment. In one embodiment, the metallic pigment is aluminum, zirconium, titanium, stainless steel, copper, or combinations thereof. In one embodiment, the PVD pigment is aluminum, zirconium, titanium, stainless steel, copper, or combinations thereof. In many embodiments, at least one metallic pigment may be mixed with organic color pigments. In many embodiments, PVD pigments particles are shaped as flat flakes with relatively high surface area and tiny edge irregularities. Not to be bound by theory, the high mobility and non-leafing properties of the PVD pigments may provide the ability to position into the drying coat, allowing them to overlap and orient parallel to the substrate below. As the metallic effect is often described as the ratio between reflected and scattered light, these flat and regular particles will enhance mono-directional light reflection and suppress multi-directional light scattering. As such, a sharper image is reflected as the gloss is increased in these coatings containing PVD pigments.

[0032] In many embodiments, at least one metallic basecoat may be mixed with at least one reducer prior to application to the undercoat layer. In many embodiments, at least one metallic basecoat is reduced at least 10% prior to coating the undercoat layer. In some embodiments, at least one metallic basecoat is reduced at least 20% prior to coating the undercoat layer. In another embodiment, at least one metallic basecoat is reduced at least 30% prior to coating the undercoat layer. In yet another embodiment, at least one metallic basecoat is reduced at least 40% prior to coating the undercoat layer. In one embodiment, at least one metallic basecoat is mixed with at least one reducer in a 2: 1 ratio. In one embodiment, at least one metallic basecoat is mixed with at least one reducer in a 3:2 ratio. In one embodiment, at least one metallic basecoat is mixed with at least one reducer in a 2: 1 ratio. In one embodiment, at least one metallic basecoat is mixed with at least one reducer in a 3 : 1 ratio. In one embodiment, at least one metallic basecoat is mixed with at least one reducer in a 4: 1 ratio. Other ratios are also contemplated. At least one metallic basecoat may be reduced by any type of reducer (also known as a thinner). Reducers thin the paint to help to help flow and leveling properties and provide an improved appearance. In many embodiments, the reducer comprises at least one ketone. At least one ketone may comprise methyl isobutylketone, methyl isoamyl ketone, methyl propyl ketone, methyl n-Amyl Ketone (MAK), or combinations thereof. Other ketones are also contemplated. A reducer may be a urethane, a solvent, an epoxy, an acrylic, a polyester, or combinations thereof. Other types of reducers are contemplated.

[0033] In many embodiments, a first layer of the metallic basecoat has a dry film thickness less than 2 pm. In some embodiments, a first layer of the metallic basecoat has a dry film thickness less than 1 pm.

[0034] In many embodiments, a second layer of the metallic basecoat is applied substantially perpendicular to the first layer of the metallic basecoat. In many embodiments, the second layer of the metallic basecoat has a dry film thickness less than 5 pm. In other embodiments, the second layer of the metallic basecoat has a dry film thickness less than 3 pm.

[0035] In many embodiments, a third layer of the metallic basecoat is applied substantially perpendicular to the second layer of the metallic basecoat. In many embodiments, the third layer of the metallic basecoat has a dry film thickness less than 5 pm. In some embodiments, the third layer of the metallic basecoat has a dry film thickness less than 3 pm.

[0036] In many embodiments, a fourth layer of the metallic basecoat is applied substantially perpendicular to the third layer of the metallic basecoat. In some embodiments, the fourth layer of the metallic basecoat has a dry film thickness less than 2 pm. In one embodiment, the fourth layer of the metallic basecoat has a dry film thickness less than 1 pm.

[0037] In one embodiment, the method of applying a metallic coating system further comprises: applying at least one dropcoat layer at an angle / diagonal to substantially bisect any of the first layer of the metallic basecoat, the second layer of the metallic basecoat, the third layer of the metallic basecoat, the fourth layer of the metallic basecoat, or combinations thereof. In some embodiments, the dropcoat layer has a dry film thickness less than 5 pm. In other embodiments, the dropcoat layer has a dry film thickness less than 3 pm.

[0038] In several embodiments, the method of applying a metallic coating system further comprises: applying at least one dropcoat layer at an angle / diagonal to substantially bisect at least one metallic basecoat. In many embodiments, at least one dropcoat layer is the same or is substantially similar to the PVD metallic basecoat composition. In some embodiments, the dropcoat layer has a dry film thickness less than 5 pm. In other embodiments, the dropcoat layer has a dry film thickness less than 3 pm.

[0039] In many embodiments, the method of applying a metallic coating system further comprises: applying at least one primer onto the substrate prior to applying at least one undercoat layer.

[0040] In many embodiments, the method of applying a metallic coating system further comprises: applying at least one clearcoat to at least one metallic basecoat, at least one dropcoat layer, or combinations thereof.

[0041] In some embodiments, the metallic coating system described herein is waterborne. In other embodiments, the metallic coating system described herein is solvent borne. In yet other embodiments, the metallic coating system described herein may be combinations of both waterborne and solvent borne coatings.

[0042] Also described herein is an article comprising: 1) a substrate having at least one major surface; and 2) the metallic coating system prepared by the method described herein, wherein the metallic coating system is at least partially coated onto the substrate, wherein the substrate comprises wood, metal, glass, plastic, paper, leather, fabric, ceramic, or any combination thereof. The method of applying a metallic coating system comprises the steps of: 1) applying at least one undercoat layer to at least one substrate; and 2) coating the undercoat layer with at least one metallic basecoat. At least one waterborne metallic basecoat may comprise at least one metallic pigment in an acrylic dispersion, wherein at least one metallic pigment is a PVD pigment. At least one solventbome metallic basecoat may comprise at least one metallic pigment in an acrylic resin solution, wherein at least one metallic pigment is a PVD pigment.

[0043] FIG. 1 illustrates a conventional metallic coating system 100. For the application of the conventional metallic coating system 100 shown, the coatings are typically sprayed by HVLP. All coatings of the coatings system described in FIG. 1 may be cured at room temperature (20 °C to 25 °C) or elevated temperatures like 60 °C for 30-60 minutes, depending on the formulation designed for that coating within the conventional metallic coating system 100. Depending on the type of repair, a primer 110 is optional. After the primer 110 has adequately dried, it must be sanded if it is a sanding primer, for example with P400-P500 sanding steps. If the primer 110 is a non-sanding primer, then no sanding is needed. There may be more than one layer of primer 110. Next, an optional undercoat layer 120 may be applied. The undercoat layer 120 should be a basecoat with certain desired colors. Like the primer 110, the undercoat layer 120 should be dried before continuing to the next step. There may be more than one undercoat layer 120. With the nextstep, the metallic basecoat layer 130 containing a conventional metallic toner is applied. This metallic basecoat may contain traditional metallic pigments such as cornflake aluminum pigments and silver dollar aluminum pigments. The metallic basecoat layer 130 may be thinned down with 10% reducer and applied in at least two wet layers to cover. Drying between the two wet layers is optional. After the metallic basecoat layer 130 layer is dry, a dropcoat layer (not shown) either similar or identical to the metallic basecoat layer 130, may be applied at a lower pressure than the metallic basecoat layer 130 but with a similar dry film thickness. The dropcoat layer may provide better blending, especially with metallics like silvers and golds that are prone to a halo effect on the edges by reducing or eliminating the dry edge. Finally, after the metallic basecoat layer 130 is adequately dry, then at least one clearcoat 140 can be applied. At least one clearcoat 140 may provide a glossy appearance and improved durability.

[0044] In some instances, the same method as described in FIG. 1 for conventional metallic coating system 100 may be used for metallic basecoats which contain PVD metallic pigments instead of conventional metallic pigments.

[0045] The conventional method described in FIG. 1 is requires at least five coatings layers and is time-consuming to apply. Therefore, a system with less coatings layers and one that takes less time to apply is desirable.

[0046] FIG. 2 illustrates one option for a conventional metallic coating system with PVD metallic pigments. The application method for conventional metallic coatings systems (shown in FIG. 1) and PVD metallic coatings systems are typically different. There are more steps and more layers required to achieve the targeted appearance of a PVD metallic basecoat. Therefore, the currently available methods for PVD metallic coating systems are both time consuming and complicated compared to conventional metallic coating systems as described in FIG. 1.

[0047] FIG. 2 provides an example of a first conventional PVD metallic coating system 200. First, primer 210 in FIG. 2 is applied to a substrate and dried. The primer 210 is then typically sanded. The primer 210, for example, may be sanded with P600-P800-P1000 sanding steps. Then, one layer of the leveling binder 220 is applied and dried. The leveling binder 220 serves to provide a consistent surface, especially after the sanding process on the primer 210, and remove any sanding scratches. At least one undercoat layer 230 may be applied after the leveling binder 220 has dried, but this step is optional. The undercoat layer 230 is typically a basecoat with certain pigments and may be substantially similar or identical to the PVD metallic basecoat 240. After the undercoatlayer 230 is dry, the PVD metallic basecoat 240 containing PVD metallic pigments may be applied. In some embodiments, the PVD metallic basecoat 240 may be thinned with 10%-50% reducer. First, a roughly 25% layer of the PVD metallic basecoat 240 is applied and allowed to dry. Then, typically five additional coats of the PVD metallic basecoat 240 with roughly 75% layers are applied crosswise. Between each layer, the PVD metallic basecoat 240 should be dried, adding both time and labor to the process. A final layer of PVD metallic basecoat 240 with roughly a 25% layer is then applied and allowed to dry for 20-30 minutes at room temperature. Finally, at least one clearcoat 250 can be applied first in a partial or medium closed coat, with 3-5 minutes drying and followed by a full coat of clearcoat 250.

[0048] FIG. 3 illustrates a second option for a conventional metallic coating system with PVD metallic pigments. Like the application method shown in FIG. 2, the application method for conventional metallic coatings systems (shown in FIG. 1) and PVD metallic coating systems are typically different. There are more steps and more layers required to achieve the targeted appearance of a PVD metallic basecoat, making it both time consuming and complicated.

[0049] First, a primer 310 in FIG. 3 is applied and dried. The primer 310 may be sanded. For example, the primer 310 may be sanded with P600-P800 sanding steps. Then, at least one partial layer and at least one full layer of clearcoat 320 (layer no. 2) are applied over the primer 310. The clearcoat 320 is typically dried at elevated temperature for 30 minutes or allowed to dry at room temperature overnight. Next, this clearcoat 320 may be sanded. For example, the clearcoat 320 may be sanded with P1500-P3000 sanding steps over the area where the color will be applied, while areas where no color is applied should be sanded with final sanding step at a minimum of P1500 or finer. Then, at least one partial layer and at least one full layer of the leveling binder 330 is applied and dried. The PVD metallic basecoat 340 may be typically thinned down with 10-50% reducer and applied using typically 2-3 coats on top of the clearcoat 320 with drying in between all coats. Then, at least one full coat of PVD metallic basecoat 340 (not thinned down) can be applied on top of the thinned down coats of PVD metallic basecoat 340. This top layer of PVD metallic basecoat 340 should be dried, then at least one clearcoat 350 can be applied. Both partial and full coats of clearcoat 350 may be applied with drying in between layers.

[0050] FIG. 4 illustrates the metallic coating system claimed and described herein. Depending on the type of repair, a primer 410 may be applied to a substrate. The primer 410 in FIG. 4 is optional. If a primer 410 is needed, the color of the primer 410 may be substantially similar or identical tothe undercoat layer 420, or it may be different from the undercoat layer 420. The undercoat layer 420 may be used to improve the hiding properties of the PVD metallic basecoat 430 to be applied over it. In many embodiments, the primer 410 may be sanded after drying and prior to application of the undercoat layer 420. In some embodiments, the primer 410 may be sanded with P500, P600, and P800 sanding steps. Other sanding techniques are also contemplated.

[0051] In some embodiments, the undercoat layer 420 may be waterborne. In one embodiment, the undercoat layer 420 is a pigmented acrylic dispersion. In another embodiment, the undercoat layer 420 is a pigmented acrylic resin solution.

[0052] In another embodiment, the undercoat layer 420 may be solventbome.

[0053] In some embodiments, the undercoat layer 420 is mixed with a reducer prior to application. In one embodiment, the at least one undercoat layer 420 is mixed with at least one reducer in a 1 : 1 ratio. In one embodiment, the at least one undercoat layer 420 is mixed with at least one reducer in a 2: 1 ratio. In many embodiments, at least one undercoat layer 420 is reduced at least 10% prior to coating the substrate. In other embodiments, least one undercoat layer 420 is reduced at least 20% prior to coating the substrate. In yet other embodiments, least one undercoat layer 420 is reduced at least 30% prior to coating the substrate. In another embodiment, least one undercoat layer 420 is reduced at least 40% prior to coating the substrate. In yet another embodiment, least one undercoat layer 420 is reduced at least 50% prior to coating the substrate. Other ratios for undercoat layer 420 to reducer are also contemplated.

[0054] In some embodiments, the undercoat layer is black or a shade of black. In other embodiments, the undercoat layer is a shade of grey. In most embodiments, the undercoat layer is colored such to match the color of the substrate to be coated.

[0055] After the primer 410 is dry, it is typically sanded to ensure a smooth substrate. Sanding, for example, may be done using P500-P600-P800-P1000 sanding steps. Afterwards, the undercoat layer 420 may be applied. The undercoat 420 should be a basecoat with certain colors. The color of the undercoat layer 420 will typically have influence for the color of the final appearance. The undercoat layer 420 may be thinned down with reducer and applied until covered. The undercoat layer 420 may be thinned with reducer in a range of 10% to 50%. The undercoat layer 420 is then dried before continuing to the next step. Next, the PVD metallic basecoat 430 may be applied. In some embodiments, the PVD metallic basecoat 430 may be thinned down and applied. The PVD metallic basecoat 430 may be thinned with reducer in a range of 10% to 50%.

[0056] The method of application for the PVD metallic basecoat 430 is further described in detail in FIG. 5. First a mistcoat layer (sometimes referred to as a “control layer” and defined herein as a partial layer of PVD metallic basecoat 430 in which the coating is sprayed in a mist instead of a full spray) should be applied and dried. Then, either two full layers (meaning a full spray) of PVD metallic basecoat 430 or two partial layers (meaning 50% layer to 90% layer) of PVD metallic basecoat 430 should be applied with drying in between the layers. In one embodiment, two 75% layers of PVD metallic basecoat 430 should be applied with drying in between the layers. An optional partial layer of PVD metallic basecoat 430 ranging from a 20% layer to a 70% layer may then be applied and dried. Finally, two dropcoat layers (defined as the PVD metallic basecoat 430 applied at a lower pressure with output ranging from 30% to 90%), either with or without a reducer) should be applied with drying in between the two dropcoat layers. In some embodiments, at least one additional dropcoat layer may be needed to ensure an even distribution of effect pigments. Using this PVD metallic coating system 400 method, a streamlined method of applied a PVD metallic coating can be obtained, providing an advantage over traditional PVD metallic coatings.

[0057] In yet another version of FIG. 4, a total of five layers of consecutive PVD metallic basecoat 430 are applied, each layer being 6 to 8 microns thick. In this embodiment, the total PVD basecoat layer 430 thickness is between 30 and 40 microns. As a comparison, typical metallic coatings may range in thickness from 10 to 12 microns.

[0058] Last, at least one clearcoat 440 can be applied on top of the PVD metallic basecoat 430. This clearcoat 440 may range in thickness from 50 to 80 microns. The clearcoat 440 is typically applied in either in: 1) a partial mist layer and a full layer or 2) two full layers, with each layer being about 25 to 40 microns thick.

[0059] FIG. 5 illustrates an exemplary application of the method described herein, specifically application steps for the metallic basecoat. With step 1, a mist coat is applied in a particular direction. A mist coat is the same composition as the metallic basecoat but applied at a similar pressure as the other layers but has a lower dry film thickness. The reduced film thickness may be achieved by spraying the article at a further distance. After the mist coat is applied, it is allowed to dry. Next in step 2, a full layer of the metallic basecoat is applied in a direction that is substantially perpendicular to the mist coat in step 1. After the PVD metallic basecoat is applied, it is allowed to dry. For step 3, another full layer of the PVD metallic basecoat is applied in a direction that is substantially perpendicular to the metallic basecoat in step 2. After the PVDmetallic basecoat is applied, it is allowed to dry. With step 4, a PVD metallic basecoat that has been is partially applied in a direction that is substantially perpendicular to the metallic basecoat in step 3. In this case, there is a 50% application compared to what was applied in steps 2 and 3. However, the PVD metallic basecoat that has been is partially applied may range from 20% to 80% of full application used in steps 2 and 3. After the PVD metallic basecoat that has been reduced is applied, it is allowed to dry. Last in step 5, at least two dropcoat layers are sprayed at an angle / di agonal to substantially bisect at least one PVD metallic basecoat. For the dropcoat layer, two dropcoat layers may have a dry film thickness less than 5 pm. An optional clearcoat (not shown) may be applied to the dried PVD metallic basecoat.

[0060] Test resultsTwo tests are used for the appearance of metallic coatings, flop index and graininess. Differences in flop index and graininess may especially be seen with the use of PVD metallic coatings compared to conventional metallic coatings. Flop index (also referred as metallic effect) is the change of metallic reflection color as it is rotate through different viewing angles. It is also known as metallic travel, since the color should be bright where the light hits and becomes darker when viewed from different angle. A high flop index surface will show a bright reflection when observed from the face (normal to the surface) and a dark reflection when observed at oblique angles. Due to its excellent mono-directional reflection, PVD particles usually presents higher flop index compared to conventional aluminum pigments. Graininess (also referred to as diffuse coarseness) is the measurement of the coarseness of the final appearance. Graininess characterizes the visibility of particles under diffuse illumination. Graininess has been described as “[t]he sensation of nonuniformity in a surface produced in the consciousness of the observer only when such a surface is viewed under diffuse or partially diffuse illumination.” The sparkle is related to the number of sparkling particles per unit of paint surface area and their intensity. Similarly, one of the sparkle definitions is: “The sensation of randomly distributed, unstable and highly luminous objects on a more extended and darker surface with uncorrelated lightness.” (from Filip et al., J. Coat. Technology, Res. Vol. 18, pp 1511-1530, (2021)).

[0061] These properties are related to the morphology, size, orientation, and concentration of pigment particles into a metallic coat: coarser and randomly oriented metallic particles (larger than 25pm) will cause the surface to show sparkle points that confer a brilliant yet glittery appearance. On the other hand, smaller and well-oriented particles will yield a brilliant and highly reflectivelook while preserving a shiny metallic finish. Unlike typical cornflake and silver dollar pigments that lay on each other at different angles resulting in high sparkle and a glittery appearance, PVD metallic pigments lay on each other at similar angles and flat on the surface to provide a chrome- like appearance.

[0062] PVD metallic basecoat should have much higher flop index and lower graininess value compared to conventional metallic basecoat. As provided below in Table 1, application methods described in the examples and Figures described above resulted in the following results for flop index and graininess.

[0063] Flop index, a measure of the change in lightness of a metallic color as it is tilted through the entire range of viewing angles. The flop index can be described as the change of reflectance of the metallic coating during the measurement through a range of viewing angles. A flop index of 0 indicates a solid color, while a very high flop metallic or pearlescent basecoat / clearcoat color may have a flop index of 15-17. Flop index is typically measured using a multiangle spectrophotometer, such as a BYK mac spectrophotometer. The test for “flop index” is described in “Observation and Measurement of the Appearance of Metallic Materials - Part 1- Macro Appearance,” C. S. McCamy, Color Research and Application, Volume 21, Number 4, August 1996, pp. 292-304. Namely, the flop index is defined by:Flop Indexwherein:L15 is CIE L* value measured at the aspecular angle of 15°;L45 is CIE L* value measured at the aspecular angle of 45°; andLuo is CIE L* value measured at the aspecular angle of 110°.

[0064] Graininess was measured by a commercial instrument such as BKY-Mac-I to measure texture effects. The multi-angle spectrophotometer BYK-Mac-I includes a CCD monochrome camera for measuring texture effects Graininess is evaluated by taking a picture with the CCD camera under diffused lighting conditions, created by a white coated hemisphere. The picture is then analyzed using the histogram of lightness levels whereby the uniformity of light and dark areas is summarized in one graininess value. A graininess value of zero would indicate a solid color, the higher the value the grainier or coarser the sample will look under diffused light. Sparkle and graininess data give information on flakesize and concentration levels. Visually, the silver finish with the coarser aluminum pigments appears more sparkling under direct illumination and more “grainy” under diffused lighting.

[0065] Table 1: Test Results

[0066] All application methods above in Table 1 were evaluated in car color Mercedes Benz 0047 (Alubeam Silver). The result using the application method in this invention (Example 4) matches the OEM reference panel better than the other application methods (higher flop index and lower graininess value), while providing a faster and simpler process compared to the current available solutions in the market.

[0067] Table 2: Additional Test Results using Reducer

[0068] Application methods shown in Table 2 were evaluated in both car colors Toyota 1L3 and Nissan KAB, containing respectively 98% and 91% PVD metallic basecoat mixed with othercolors. The result using the application method described herein (Example C) matches the OEM reference panel better than the other application methods and also provides a higher flop index and lower graininess value. Example C utilizes the PVD metallic basecoat described herein with an undercoat layer containing a 1 : 1 ratio with a reducer. The reducer contains a mix of ketones, namely methyl isobutyl ketone and methyl isoamyl ketone. Further, Example C also provides a faster and simpler process compared to the current available solutions in the market.

[0069] Embodiments

[0070] The following embodiments are contemplated. All combinations of features and embodiments are contemplated.

[0071] Embodiment 1 : A method of applying a metallic coating system comprising the steps of: 1) applying at least one undercoat layer to at least one substrate; and 2) coating the undercoat layer with at least one metallic basecoat.

[0072] Embodiment 2: An embodiment of Embodiment 1, wherein at least one substrate wherein the substrate comprises wood, metal, glass, plastic, paper, leather, fabric, ceramic, or any combination thereof.

[0073] Embodiment 3: An embodiment of any of Embodiments 1-2, wherein at least one undercoat layer comprises a pigmented dispersion, wherein the pigmented dispersion comprises at least one acrylic.

[0074] Embodiment 4: An embodiment of any of Embodiments 1-3, wherein at least one undercoat layer is reduced at least 10% prior to coating the substrate.

[0075] Embodiment 5: An embodiment of any of Embodiments 1-3, wherein at least one undercoat layer is reduced at least 20% prior to coating the substrate.

[0076] Embodiment 6: An embodiment of any of Embodiments 1-5, wherein at least one undercoat layer is mixed with at least one reducer in a ratio ranging from 1 : 1 to 2: 1 prior to coating the substrate.

[0077] Embodiment 7: An embodiment of any of Embodiments 1-6, wherein at least one metallic basecoat comprises at least one metallic pigment in an acrylic dispersion.

[0078] Embodiment 8: An embodiment of Embodiment 7, wherein at least one metallic pigment is a PVD pigment.

[0079] Embodiment 9: An embodiment of any of Embodiments 1-8, wherein at least one metallic basecoat is reduced at least 10% prior to coating the undercoat layer.

[0080] Embodiment 10: An embodiment of any of Embodiments 1-8, wherein at least one metallic basecoat is reduced at least 20% prior to coating the undercoat layer.

[0081] Embodiment 11 : An embodiment of any of Embodiments 1-10, wherein a first layer of the metallic basecoat has a dry film thickness less than 2 pm.

[0082] Embodiment 12: An embodiment of Embodiment 11, wherein a second layer of the metallic basecoat is applied substantially perpendicular to the first layer of the metallic basecoat.

[0083] Embodiment 13: An embodiment of Embodiment 12, wherein the second layer of the metallic basecoat has a dry film thickness less than 5 pm.

[0084] Embodiment 14: An embodiment of Embodiment 12, wherein a third layer of the metallic basecoat is applied substantially perpendicular to the second layer of the metallic basecoat.

[0085] Embodiment 15: An embodiment of Embodiment 14, wherein the third layer of the metallic basecoat has a dry film thickness less than 5 pm.

[0086] Embodiment 16: An embodiment of Embodiment 14, wherein a fourth layer of the metallic basecoat is applied substantially perpendicular to the third layer of the metallic basecoat.

[0087] Embodiment 17: An embodiment of Embodiment 16, wherein the fourth layer of the metallic basecoat has a dry film thickness less than 2 pm.

[0088] Embodiment 18: An embodiment of any of Embodiments 16-17 further comprising: applying at least one dropcoat layer at an angle / diagonal to substantially bisect any of the first layer of the metallic basecoat, the second layer of the metallic basecoat, the third layer of the metallic basecoat, the fourth layer of the metallic basecoat, or combinations thereof.

[0089] Embodiment 19: An embodiment of any of Embodiments 1-17 further comprising: applying at least one dropcoat layer at an angle / diagonal to substantially bisect at least one metallic basecoat.

[0090] Embodiment 20: An embodiment of any of Embodiments 18-19, wherein the dropcoat layer has a dry film thickness less than 5 pm.

[0091] Embodiment 21: An embodiment of any of Embodiments 1-20 further comprising: applying at least one primer onto the substrate prior to applying at least one undercoat layer.

[0092] Embodiment 22: An embodiment of any of Embodiments 1-21 further comprising: applying at least one clearcoat to at least one metallic basecoat, at least one dropcoat layer, or combinations thereof.

[0093] Embodiment 23 : An article comprising: 1) a substrate having at least one major surface; and 2) the metallic coating system prepared by any of Embodiments 1-22, wherein the metallic coating system is at least partially coated onto the substrate, wherein the substrate comprises wood, metal, glass, plastic, paper, leather, fabric, ceramic, or any combination thereof.

[0094] What has been described above includes examples of the claimed subject matter. All details and any described modifications in connection with the Background and Detailed Description are within the spirit and scope of the claimed subject matter will be readily apparent to those of skill in the art. In addition, it should be understood that aspects of the claimed subject matter and portions of various embodiments and various features recited below and / or in the appended claims may be combined or interchanged either in whole or in part. In the foregoing descriptions of the various embodiments, those embodiments which refer to another embodiment may be appropriately combined with other embodiments as will be appreciated by one of skill in the art. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only and is not intended to limit the claimed subject matter, realizing that many further combinations and permutations of the claimed subject matter are possible. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the claimed subject matter, but one of ordinary skill in the art may recognize. Accordingly, the claimed subject matter is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims. Furthermore, to the extent that the term “includes” is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term “comprising” as “comprising” is interpreted when employed as a transitional word in a claim.

Claims

What is claimed is:

1. A method of applying a metallic coating system comprising the steps of: applying at least one undercoat layer to at least one substrate; and coating the undercoat layer with at least one metallic basecoat.

2. The method of Claim 1, wherein at least one substrate wherein the substrate comprises wood, metal, glass, plastic, paper, leather, fabric, ceramic, or any combination thereof.

3. The method of any of Claims 1-2, wherein at least one undercoat layer comprises a pigmented dispersion, wherein the pigmented dispersion comprises at least one acrylic.

4. The method of any of Claims 1-3, wherein at least one undercoat layer is reduced at least 10% prior to coating the substrate.

5. The method of any of Claims 1-3, wherein at least one undercoat layer is reduced at least 20% prior to coating the substrate.

6. The method of any of Claims 1-5, wherein at least one undercoat layer is mixed with at least one reducer in a 1 :1 to 2: 1 ratio prior to coating the substrate.

7. The method of any of Claims 1-6, wherein at least one metallic basecoat comprises at least one metallic pigment in an acrylic dispersion.

8. The method of Claim 7, wherein at least one metallic pigment is a PVD pigment.

9. The method of any of Claims 1-8, wherein at least one metallic basecoat is reduced at least 10% prior to coating the undercoat layer.

10. The method of any of Claims 1-8, wherein at least one metallic basecoat is reduced at least 20% prior to coating the undercoat layer.

11. The method of any of Claims 1-10, wherein a first layer of the metallic basecoat has a dry film thickness less than 2 pm.

12. The method of Claim 11, wherein a second layer of the metallic basecoat is applied substantially perpendicular to the first layer of the metallic basecoat.

13. The method of Claim 12, wherein the second layer of the metallic basecoat has a dry film thickness less than 5 pm.

14. The method of Claim 12, wherein a third layer of the metallic basecoat is applied substantially perpendicular to the second layer of the metallic basecoat.

15. The method of Claim 14, wherein the third layer of the metallic basecoat has a dry film thickness less than 5 pm.

16. The method of Claim 14, wherein a fourth layer of the metallic basecoat is applied substantially perpendicular to the third layer of the metallic basecoat.

17. The method of Claim 16, wherein the fourth layer of the metallic basecoat has a dry film thickness less than 2 pm.

18. The method of any of Claims 16-17 further comprising: applying at least one dropcoat layer at an angle / diagonal to substantially bisect any of the first layer of the metallic basecoat, the second layer of the metallic basecoat, the third layer of the metallic basecoat, the fourth layer of the metallic basecoat, or combinations thereof.

19. The method of any of Claims 1-17 further comprising:applying at least one dropcoat layer at an angle / diagonal to substantially bisect at least one metallic basecoat.

20. The method of any of Claims 18-19, wherein the dropcoat layer has a dry film thickness less than 5 pm.

21. The method of any of Claims 1-20 further comprising: applying at least one primer onto the substrate prior to applying at least one undercoat layer.

22. The method of any of Claims 1-21 further comprising: applying at least one clearcoat to at least one metallic basecoat, at least one dropcoat layer, or combinations thereof.

23. An article comprising: a substrate having at least one major surface; and the metallic coating system prepared by any of Claims 1-22, wherein the metallic coating system is at least partially coated onto the substrate; wherein the substrate comprises wood, metal, glass, plastic, paper, leather, fabric, ceramic, or any combination thereof.

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