Method of applying solvent-borne coating composition to substrate by utilizing high transfer efficiency applicator to form coating layer thereon

Abstract

To provide a method for forming a coating layer on a substrate by a high transfer efficiency applicator while minimizing sag of a composition.SOLUTION: A method includes a step of applying a coating composition to a substrate through a high transfer efficiency applicator to form a coating layer on the substrate, where loss of volatiles is less than about 0.5 mass, and where the coating composition comprises: A. resin comprising an acrylic, a polyester, or combinations thereof; B. a melamine cross-linker; C. an optional pigment; D. an organic solvent; and E. at least one polyurea crystal sag control agent, where the polyurea crystal sag control agent is a reaction product of an amine and an isocyanate, has a melting point of from about 50°C to about 150°C, and is present in an amount of from about 0.1 to about 4 mass percent based on total weight of the coating composition, and where the coating composition has wet film thickness of at least about 30 microns measured at about 45 degrees without visible sag.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates generally to a method for applying a solvent-based coating composition to a substrate utilizing a high transfer efficiency applicator to form a coating layer on the substrate. More specifically, the present disclosure relates to the use of certain polyurea crystalline sag control agents that minimize sag of the composition while still allowing the composition to be applied through a high transfer efficiency applicator and cured to have excellent physical and aesthetic properties. [Background technology]

[0002] Inkjet printing is a non-impact printing process in which droplets of ink are deposited onto a substrate (typically paper or fabric) in response to an electronic signal. This application process has the advantage of allowing digital printing of substrates that can be tailored to individual requirements. The droplets can be jetted onto the substrate by various inkjet application methods, such as continuous printing and drop-on-demand printing. In drop-on-demand printing, the energy to eject the ink droplets can be obtained from thermal resistors, piezoelectric crystals, acoustic or solenoid valves. These methods use high transfer efficiency applicators. In the automotive industry, vehicle bodies are typically covered with a series of finishes, including an electrocoat, a primer coat, a pigmented basecoat to provide color, and a clear topcoat to provide additional protection and a glossy finish. Most modern automotive bodies are painted a single color with the basecoat applied in a single spray action. The coating is applied using pneumatic atomizing or rotary equipment that produces a wide jet of paint droplets with a wide droplet size distribution. This has the advantage of producing a uniform, high-quality coating in a relatively short time through an automated process. However, this process has many drawbacks. If a vehicle body is to be painted in multiple colors, for example, if a second color is used in a pattern such as stripes, or if an entire section of the vehicle body, such as the roof, is painted a different color, this requires masking the first coating and then putting the vehicle through a second paint spraying process to add the second color. After this second paint job, the masking must be removed. This is both time-consuming and labor-intensive, significantly increasing the cost of the job. A second drawback of current spray technology is that paint droplets are sprayed in a wide droplet jet with a wide range of droplet sizes. As a result, many of the droplets do not land on the vehicle, either because the droplets are sprayed near the edge and overspray the substrate, or because the momentum of the smaller droplets is too low to reach the vehicle body. This excess overspray must be removed from the spray operation and safely disposed of, resulting in a large amount of waste and additional costs.

[0003] Applying coatings using a high transfer efficiency applicator provides a solution for applying two colors to a vehicle and for minimizing overspray by generating uniformly sized droplets that can be directed to specific points on the substrate (e.g., specific locations on the vehicle body), thereby minimizing or completely eliminating overspray droplets. Additionally, digital printing can be used to print patterns or two-tones on a vehicle body, either as a digitally printed second color over a pre-sprayed base coat of a different color, or as a second color printed directly onto a primed or clear-coated vehicle substrate. However, conventional inkjet inks are typically formulated to print on porous substrates such as paper and textiles, where the ink is rapidly absorbed by the substrate, thereby facilitating the drying and handling of the substrate immediately after printing. In addition, while printed articles, such as printed text and images or patterned textiles, have sufficient durability for these applications, the durability requirements for automotive coatings are much higher, both in terms of physical durability, such as resistance to abrasion and chipping, and long-term durability against weathering and lightfastness. Furthermore, inkjet inks known in the art are formulated to have low viscosity, generally shear rate independent, i.e., Newtonian, typically less than 20 cps. This is due to the limited amount of energy available at each nozzle of the printhead to eject droplets and to avoid thickening of the ink in the printhead channels, which can lead to clogging. In contrast, automotive coatings typically exhibit significant non-Newtonian shear behavior, having very high viscosities at low shear to help avoid pigment settling and ensure rapid and uniform curing of the coating immediately after application, but relatively low viscosities at high shear rates to facilitate spraying and atomization of the spray into droplets.

[0004] Furthermore, even though current technology is suitable for use in some horizontal surface applications, there remain other applications, such as vertical surface applications, where current technology sags at levels that are unacceptable. High transfer efficiency applicators require very low viscosities that do not exhibit shear-thinning behavior, preventing the use of standard approaches to impart sag resistance to spray-applied coatings. More specifically, zero-overspray applicators (continuous flow) or high-resolution drop-on-demand (i.e., "inkjet" printheads) typically require very low high-shear viscosities. In contrast to spray atomization, thickening does not occur after the coating is ejected from the applicator and before impacting the substrate, because no solvent evaporation occurs. As a result, the coating sags on non-horizontal surfaces. To achieve sufficient sag resistance, rheology modifiers must be incorporated at high levels that prevent sag while at the same time preventing the flow and leveling that result in coating defects unique to zero-overspray applicators due to the yield stress. These defects include the visibility of nozzle lines and stripe overlap. The former results from imperfect flow and leveling of streams or droplets emitted from adjacent nozzles, resulting in visible parallel lines in the direction of printhead movement. The latter is the result of applying a second stripe of coating material (having the width of the nozzle array) adjacent to a previously applied first stripe. Varying the index (the distance between adjacent stripes) can improve this blending, but with the high levels of rheology modifiers required to prevent sag, the overlap areas show visible peaks or valleys that cannot be eliminated by optimizing the index. Additionally, the particle size limitations of these small nozzle applicators mean that some rheology control agents cannot be used due to filter and nozzle clogging. Thus, opportunities for improvement remain. Summary of the Invention

[0005] The present disclosure provides a method for applying a one-part solvent-based coating composition to a substrate using a high transfer efficiency applicator to form a coating layer disposed on the substrate, the method comprising: providing the coating composition to a high transfer efficiency applicator; applying the coating composition to a substrate through a high transfer efficiency applicator to form a coating layer on the substrate, wherein volatile loss after application through the high transfer efficiency applicator is less than about 0.5 wt. %, based on the total weight of the coating composition; Including, The coating composition comprises A. a resin including acrylic, polyester, or a combination thereof; B. a melamine crosslinker; C. optional pigments, D. an organic solvent; E. at least one polyurea crystalline sag control agent, the polyurea crystalline sag control agent being a reaction product of an amine and an isocyanate, having a melting point of from about 50°C to about 150°C, and present in an amount of from about 0.1 to about 4 weight percent, based on the total weight of the coating composition; Including, The coating composition has a wet film thickness of at least about 30 microns without visible sag when measured at about 45 degrees.

[0006] The present disclosure also provides a method for applying a two-part solvent-based coating composition to a substrate using a high transfer efficiency applicator to form a coating layer disposed on the substrate, the method comprising: providing the coating composition to a high transfer efficiency applicator; applying the coating composition to a substrate through a high transfer efficiency applicator to form a coating layer on the substrate, wherein volatile loss after application through the high transfer efficiency applicator is less than about 0.5 wt. %, based on the total weight of the coating composition; Including, The coating composition comprises A. a hydroxyl-functional resin; B. an isocyanate crosslinker; C. optional pigments, D. an organic solvent; E. at least one polyurea crystalline sag control agent, the polyurea crystalline sag control agent being a reaction product of an amine and an isocyanate, having a melting point of from about 50°C to about 150°C, and present in an amount of from about 0.1 to about 4 weight percent, based on the total weight of the coating composition; Including, The coating composition has a wet film thickness of at least about 30 microns without visible sag when measured at about 45 degrees. The present disclosure will now be described in conjunction with the following drawings, in which like numerals refer to like elements and in which: [Brief explanation of the drawings]

[0007] [Figure 1A] FIG. 1 is a top view of a high transfer efficiency applicator applying a coating composition to a substrate. [Figure 1B] FIG. 1B is a side view of FIG. 1A. [Figure 2A] FIG. 1 is a side view of a substrate with paint (coating composition) disposed thereon, showing the location of the edge nozzles of a high transfer efficiency applicator. [Figure 2B] FIG. 2B is a side view of the tilted substrate of FIG. 2A during sag measurement, with the angle of the substrate relative to the horizontal plane indicated. [Figure 3A] FIG. 1 is a side view of a high transfer efficiency applicator including multiple nozzles for applying a coating composition to a substrate, where a nozzle line can be defined as having a periodically repeating pattern with spacing that matches the spacing between nozzles on a nozzle plate. [Figure 3B] FIG. 3B is a side view of FIG. 3A showing stripes of coating applied to a substrate, where each stripe is a single pass of approximately 50 nozzles. [Figure 3C] FIG. 3B is a close-up of a single pass from FIG. 3A, where defects exist where each nozzle impacted the substrate. [Figure 4A] 1 shows phase stepped deflectometry measurements of various coating compositions of the present disclosure. [Figure 4B] 10 is a photograph showing the sag of Example 10. [Figure 4C] 10 is a photograph showing the sag of Example 11. [Figure 5] 1 is a photograph showing the sag of a comparative composition that did not incorporate a rheology control agent and resulted in very low sag resistance. [Figure 6] 1 is a photograph of a substrate with a comparative composition disposed thereon, showing visible nozzle line defects. [Figure 7]1 is a photograph of a substrate with a comparative composition disposed thereon, showing stripe overlap defects. DETAILED DESCRIPTION OF THE INVENTION

[0008] The following detailed description is merely exemplary in nature and is not intended to limit the present disclosure. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description.

[0009]

[0003] Embodiments of the present disclosure generally relate to one- and two-component solvent-borne coating compositions and methods for forming the same. For the sake of brevity, conventional techniques related to forming such compositions may not be detailed herein. Furthermore, various tasks and process steps described herein may be incorporated into more comprehensive procedures or processes having additional steps or functions not detailed herein. In particular, various steps in the manufacture of such compositions are well known, and therefore, for the sake of brevity, many conventional steps are only briefly described herein or omitted entirely without providing well-known process details.

[0010] The present disclosure provides a method for applying a one-part solvent-based coating composition to a substrate using a high transfer efficiency applicator to form a coating layer disposed on the substrate, the method comprising: providing the coating composition to a high transfer efficiency applicator; applying the coating composition to a substrate through a high transfer efficiency applicator to form a coating layer on the substrate, wherein volatile loss after application through the high transfer efficiency applicator is less than about 0.5 wt. %, based on the total weight of the coating composition; Including, The coating composition comprises A. a resin including acrylic, polyester, or a combination thereof; B. a melamine crosslinker; C. optional pigments, D. an organic solvent; E. at least one polyurea crystalline sag control agent, the polyurea crystalline sag control agent being a reaction product of an amine and an isocyanate, having a melting point of from about 50°C to about 150°C, and present in an amount of from about 0.1 to about 4 weight percent, based on the total weight of the coating composition; Including, The coating composition has a wet film thickness of at least about 30 microns without visible sag when measured at about 45 degrees. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of and therebetween, are expressly contemplated for use herein.

[0011] The present disclosure also provides a method for applying a two-part solvent-based coating composition to a substrate using a high transfer efficiency applicator to form a coating layer disposed on the substrate, the method comprising: providing the coating composition to a high transfer efficiency applicator; applying the coating composition to a substrate through a high transfer efficiency applicator to form a coating layer on the substrate, wherein volatile loss after application through the high transfer efficiency applicator is less than about 0.5 wt. %, based on the total weight of the coating composition; Including, The coating composition comprises A. a hydroxyl-functional resin; B. an isocyanate crosslinker; C. optional pigments, D. an organic solvent; E. at least one polyurea crystalline sag control agent, the polyurea crystalline sag control agent being a reaction product of an amine and an isocyanate, having a melting point of from about 50°C to about 150°C, and present in an amount of from about 0.1 to about 4 weight percent, based on the total weight of the coating composition; Including, The coating composition has a wet film thickness of at least about 30 microns without visible sag when measured at about 45 degrees. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of and therebetween, are expressly contemplated for use herein.

[0012] Throughout this disclosure, the terms "consisting essentially of" or "consisting essentially of" may describe embodiments that are free of any alternative monomers, polymers, additives, reactants, fillers, solvents, etc., as determined by one of ordinary skill in the art. The term "free of" may describe embodiments that contain less than 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.5, or 0.1 weight percent of the element in question, based on the total weight of the composition. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of and between the recited values, are expressly contemplated for use herein.

[0013] The present disclosure includes a process for applying a coating composition to a substrate. The applying process is not particularly limited. In various embodiments, the applying process is further defined as jetting, for example, jetting through a high transfer efficiency applicator. Alternatively, the applying process may be further defined as printing. This process is described in more detail below.

[0014] Furthermore, the coating composition is not particularly limited and may be any known in the art containing the components described herein. For example, the composition may be described as a one-part or "1K" composition, which does not require a curing agent, catalyst, or activator to cure. For example, the composition may be cured by exposure to air. Alternatively, the composition may be described as a two-part or "2K" composition.

[0015] The coating composition can be used to coat any type of substrate known in the art. In an embodiment, the substrate is a vehicle, automobile, or automotive vehicle. "Vehicle" or "automobile" or "automobile vehicle" includes automobiles such as cars, vans, minivans, buses, and SUVs (sport utility vehicles); trucks; semi-trucks; tractors; motorcycles; trailers; ATVs (all-terrain vehicles); pickup trucks; large vehicles such as bulldozers, cranes, and earthmoving machines; aircraft; boats; watercraft; and other forms of transportation. The coating composition can also be used to coat substrates in industrial applications such as buildings, fences, ceramic tiles, stationary structures, bridges, pipes, and cellulosic materials (e.g., wood, paper, textiles, etc.). The coating composition can also be used to coat substrates in consumer product applications such as helmets, baseball bats, bicycles, and toys. It should be understood that the term "substrate" as used herein can also refer to a coating layer disposed on an article that is also considered a substrate. Various substrates may include two or more separate portions of different materials. For example, a vehicle may include a body portion containing metal and a trim portion containing plastic. Because the bake temperature of plastic (80°C) is limited compared to that of metal (140°C), the body portion containing metal and the trim portion containing plastic are traditionally coated in separate facilities, which can increase the possibility of incompatibility of the coated parts. A coating composition suitable for a plastic substrate can be applied to the plastic substrate using a high-transfer efficiency applicator after application and baking of a coating suitable for a metal substrate, without having to mask the substrate or waste a portion of the coating composition using a low-transfer efficiency application method such as conventional spray atomization. The coating composition suitable for a plastic substrate may be applied using a first high-transfer efficiency applicator, and the coating composition suitable for a metal substrate may be applied using a second high-transfer efficiency applicator. The first high-transfer efficiency applicator and the second high-transfer efficiency applicator may form a high-transfer efficiency applicator assembly.

[0016] The method of the present invention includes providing a coating composition to a high-transfer efficiency applicator. The providing step is not particularly limited and may be any step known in the art. For example, the providing step may be described as providing all or a portion of one or more components of the composition, combining these components to form a composition, and then providing the finished composition. Alternatively, the providing step may be described as pumping, flowing, transferring, or otherwise delivering one or more components of the composition or the entire composition to the high-transfer efficiency applicator. The providing step may be described as a continuous process or a batch process. Similarly, the providing step may include continuous sub-steps and / or batch sub-steps. In various embodiments, the providing step is described as pumping the composition to the applicator under pressure. The providing step may be any step understood by one of ordinary skill in the art.

[0017] The method of the present invention also includes applying the coating composition to a substrate through a high-transfer efficiency applicator to form a coating layer on the substrate. Typically, applying is further defined as spraying or printing through, with, or by an applicator. During applying, the loss of volatiles after application through the high-transfer efficiency applicator is less than about 0.5% by weight, based on the total weight of the coating composition. In various embodiments, this amount is less than about 0.4, 0.3, 0.2, or 0.1% by weight, based on the total weight of the coating composition. Typically, the term "volatiles" is defined as materials that evaporate, resulting in a loss of mass of the coating composition. The loss of volatiles after application is determined by the increase in percent solids after oven drying before application, with the percent solids in each case determined gravimetrically according to ASTM D2369-10. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of and between the above values, are expressly contemplated for use herein. In certain embodiments, the applying step produces droplets of the coating composition that impact the substrate. In various embodiments, at least about 99, 99.1, 99.2, 99.3, 99.4, 99.5, 99.6, 99.7, 99.8, 99.9%, or more of the coating composition droplets emitted from the high transfer efficiency applicator contact the substrate. Without being bound by theory, it is believed that increasing the number of droplets that contact the substrate relative to the number of droplets that enter the environment without contacting the substrate improves the efficiency of coating composition application, reduces waste generation, and reduces maintenance.

[0018] In various embodiments, at least about 99.5, 99.6, 99.7, 99.8, 99.9%, or more of the droplets of coating composition emitted from a high transfer efficiency applicator remain as single droplets after contacting the substrate. Without being bound by theory, it is believed that splashing of the coating composition resulting from impact with the substrate can be minimized or eliminated by applying the coating composition using a high transfer efficiency applicator. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of the recited values ​​and therebetween, are expressly contemplated for use herein. In various embodiments, at least about 99.5, 99.6, 99.7, 99.8, 99.9%, or more of the droplets of the coating composition ejected from the high transfer efficiency applicator remain as single droplets or streams after ejection from the high transfer efficiency applicator. Without being bound by theory, it is believed that the formation of satellite droplets can be reduced or eliminated by applying the coating composition using a high transfer efficiency applicator. Satellite droplet formation can be reduced by considering the impact velocity and nozzle diameter. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of the above values ​​and therebetween, are expressly contemplated for use herein.

[0019] In various embodiments, liquid paint is sprayed from one or more nozzles of a high-transfer-efficiency applicator in an engineered / controlled manner to produce a fine stream that may or may not break up into droplets. This stream targets the substrate so that the droplets reach specific locations, potentially forming a continuous coating or pattern on the target. As a result, in many embodiments, there is virtually no overspray (droplets that miss their target) and nearly 100% transfer efficiency (all of the paint goes to the targeted location on the substrate). As will be understood by those skilled in the art, some allowance is provided for starting and stopping high-transfer-efficiency applicators. These types of devices can be described as drop-on-demand, stream-on-demand, overspray-free, or ultra-high-transfer-efficiency applicators. These devices differ from spray-atomization devices and techniques, in which energy, such as pneumatic, hydraulic, or centrifugal energy, is introduced to produce a partially controlled, random distribution of droplet size, trajectory, and velocity, and some additional mechanism, e.g., electrostatics and / or shaping air, directs the paint droplet cloud to the substrate. With conventional paint spraying, there is always some overspray and loss of transfer efficiency.

[0020] The high transfer efficiency applicator itself may be any known in the art. For example, in various embodiments, the applicator is as described in one or more of U.S. Patent Application Publication Nos. 2015 / 0375258 (A1), 2004 / 0217202 (A1), 2009 / 0304936 (A1), U.S. Patent Application Publication No. 7,824,015 (B2), U.S. Patent No. 8,091,987 (B2), and WO 2018 / 206309 (A1), each of which is expressly incorporated herein by reference in its entirety for use in various non-limiting embodiments. The applicator may alternatively be described as a print head. In one embodiment, the high transfer efficiency applicator includes a nozzle defining a nozzle orifice and may have a nozzle diameter of about 0.00002 m to about 0.0004 m. In another embodiment, the applicator may be in fluid communication with a reservoir configured to contain a coating composition. For example, the high transfer efficiency applicator may be configured to receive a coating composition from the reservoir and to expel the coating composition through the nozzle orifice onto a substrate to form a coating layer. It is understood that the ranges for nozzle diameter, viscosity, density, surface tension, and relaxation time may be defined by any of the ranges disclosed herein or known in the art. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of the above values ​​and therebetween, are expressly contemplated for use herein.

[0021] The high transfer efficiency applicator may be configured to emit the coating composition through a nozzle orifice at an impact velocity of about 0.2 m / s to about 20 m / s. Alternatively, the high transfer efficiency applicator may be configured to emit the coating composition through a nozzle orifice at an impact velocity of about 0.4 m / s to about 10 m / s. The nozzle orifice may have a nozzle diameter of about 0.00004 m to about 0.00025 m. The coating composition may be emitted from the high transfer efficiency applicator as droplets having a particle size of at least 10 microns. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of and between the recited values, are expressly contemplated for use herein. It is contemplated that one, two, three, or more applicators may be used in conjunction with one another, and each of the applicators may independently be as described herein or any known in the art.

[0022] In various embodiments, the high transfer efficiency applicator includes a plurality of nozzles, each of which defines a nozzle orifice. The plurality of nozzles may be arranged in a linear configuration relative to one another along a first axis. For example, in various embodiments, the plurality of nozzles includes nozzle A and nozzle B adjacent to nozzle A. Nozzle A and nozzle B may be spaced apart from one another by a nozzle distance. The distance of the high transfer efficiency applicator from the substrate can be substantially the same as the nozzle distance. In one embodiment, the plurality of nozzles are spaced relative to one another to form a rectangular array, and the plurality of nozzles can be configured to alternate the release of the coating composition between adjacent nozzles in the rectangular array to reduce sag of the coating composition.

[0023] In various embodiments, the high transfer efficiency applicator includes 50 nozzles aligned along the y-axis, although it should be understood that the applicator can include any number of nozzles. Each nozzle may be actuated independently of the other nozzles to apply the coating composition to the substrate. During jetting, the independent actuation of the nozzles allows for control over the placement of each droplet of the coating composition on the substrate. Two or more applicators may be combined to form a printhead assembly. In certain embodiments, the applicators are aligned such that the y-axis of each applicator is parallel to the other y-axes. Furthermore, the nozzles of each applicator may be aligned with one another along an x-axis perpendicular to the y-axis, thereby forming an "array." A nozzle may be equally spaced from its immediately adjacent nozzle along the x-axis and y-axis. This nozzle configuration may be suitable for applying the same coating composition to a substrate by each applicator as the printhead assembly moves along the x-axis. Without being bound by theory, it is believed that equally spaced nozzles along both the x-axis and the y-axis may result in a uniform application of the same coating composition on a substrate. The uniform application of the same coating composition may be suitable for single-color application, two-tone application, and the like. Alternatively, one set of nozzles along a first y-axis may be closely spaced to another set of nozzles compared to the spacing of each of the nozzles along the y-axis of a single high transfer efficiency applicator. This configuration of nozzles may be suitable for applying different coating compositions to a substrate by each of the high transfer efficiency applicators. Utilizing different coating compositions within the same high transfer efficiency applicator assembly may be suitable for logos, designs, markings, stripes, camouflage appearances, and the like. The nozzle of the high transfer efficiency applicator can have any configuration known in the art, such as linear, concave relative to the substrate, convex relative to the substrate, circular, etc. Adjustments to the nozzle configuration may be necessary to facilitate the high transfer efficiency applicator working with substrates having irregular configurations, such as vehicles that include mirrors, trim panels, contours, spoilers, etc.

[0024] The high transfer efficiency applicator can be configured to blend the individual droplets to form the desired color. The high transfer efficiency applicator may include nozzles for applying a cyan coating composition, a magenta coating composition, a yellow coating composition, and a black coating composition. The properties of the coating compositions may be modified to facilitate blending. Additionally, an agitation source, such as air movement or a sound generator, can be used to facilitate blending of the coating compositions. The agitation source may be coupled to the high transfer efficiency applicator or separate from the applicator. Identifying suitable properties of a coating composition for use with a high transfer efficiency applicator can depend on the properties of the high transfer efficiency applicator, including, but not limited to, the nozzle diameter of the high transfer efficiency applicator, the impact velocity of the coating composition with the high transfer efficiency applicator, the speed of the high transfer efficiency applicator, the distance of the high transfer efficiency applicator from the substrate, the droplet size of the coating composition with the high transfer efficiency applicator, the firing rate of the high transfer efficiency applicator, and the orientation of the high transfer efficiency applicator relative to gravity.

[0025] In one embodiment, as shown, for example, in Figures 1A and 1B, a high transfer efficiency applicator jets a stream of composition 14 onto a substrate 16. In Figure 1A, spaces 18 are shown between stripes 20 of composition 14 disposed on the substrate 16. Preferably, these spaces 18 are minimized or eliminated. However, those skilled in the art will appreciate that overlapping stripes 20 may unintentionally result in overlapping and unwanted buildup of the composition, as well as the formation of certain "hills" or raised portions of the substrate. This, too, is preferably minimized. 3A-3C show a single nozzle line, which can be defined as having a periodically repeating pattern with spacing consistent with the spacing between nozzles of a high transfer efficiency applicator. The defects can be straight or squiggly. The defects can have multiple interruptions within them. The defects can appear smooth or raised. In FIG. 3B, each stripe is a single pass of approximately 50 nozzles. FIG. 3C shows an expanded view of FIG. 3A for a single pass of a high transfer efficiency applicator. The defects are present where each nozzle jet of composition impacted the substrate 16. In Figure 4A, phase-step deflectometry was used on an Optimap™ PSD to determine the surface profile of an area approximately 79 x 57 mm. Two coating surface profiles are shown here, including areas of stripe overlap. A color scale corresponding to the difference in coating height is shown on the left. Green represents the average coating surface height, red represents "hills" with heights greater than the average (up to 3 microns), and blue represents valleys lower than the surface average (down to 3 microns). The stripe overlap areas are observed as defects parallel to the coating direction and become increasingly visible as the hills and valleys become more pronounced. Figures 4B and 4C are photographs showing the sag of Examples 10 and 11, respectively. Figure 5 is a photograph showing the sag of a comparative composition that did not incorporate a rheology control agent and resulted in very low sag resistance. Figure 6 is a photograph of a substrate with a comparative composition disposed thereon, showing visible nozzle line defects. Figure 7 is a photograph of a substrate with a comparative composition disposed thereon, showing stripe overlap defects.

[0026] Coating composition: Now, referring to the composition itself, the composition may be solvent-based and may be a one-part composition or a two-part composition, each of which is described below.

[0027] One-component composition: In various embodiments, the composition is, comprises, consists essentially of, or consists of a resin including acrylic, polyester, or a combination thereof; a melamine crosslinker; an optional pigment; an organic solvent; and at least one polyurea crystal sag control agent. For example, the term "consisting essentially of" may describe an embodiment that is free of a resin or polymer not described or optionally described herein, a crosslinker not described or optionally described herein, a pigment not described or optionally described herein, an organic solvent not described or optionally described herein, and a sag control agent and / or a rheology control agent not described or optionally described herein. The term "free of" or "free of" may describe that the composition contains less than about 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.5, or 0.1 wt. % (e.g., wt. % active ingredient) of the compound, based on the total weight of the composition. Alternatively, the term "free of" or "free of" may describe that the composition is completely free of the compound.

[0028] Two-part composition: In various embodiments, the composition is, comprises, consists essentially of, or consists of: a hydroxyl-functional resin; an isocyanate crosslinker; an optional pigment; an organic solvent; and at least one polyurea crystal sag control agent. For example, the term "consisting essentially of" may describe embodiments that are free of a resin or polymer not described or optionally described herein, a crosslinker not described or optionally described herein, a pigment not described or optionally described herein, an organic solvent not described or optionally described herein, and a sag control agent and / or a rheology control agent not described or optionally described herein. The term "free of" or "free of" may describe that the composition contains less than about 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.5, or 0.1 wt. % (e.g., wt. % active ingredient) of the compound, based on the total weight of the composition. Alternatively, the term "free of" or "free of" may describe that the composition is completely free of the compound. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of and between the recited values, are expressly contemplated for use herein.

[0029] Resins including acrylic, polyester, or a combination thereof For one-component compositions, the resin can be, comprise, consist essentially of, or consist of acrylic, polyester, or a combination thereof. For example, the term "consisting essentially of" can describe an embodiment that does not include acrylic, polyester, or any other polymer known in the art, where "free of" is as defined above. For example, the composition and / or resin itself may include acrylic and not include polyester and / or any other polymer. Alternatively, the composition and / or resin itself may include polyester and not include acrylic and / or any other polymer. The composition and / or resin itself may include both acrylic and polyester and not include any other polymer.

[0030] In various embodiments, the acrylic is selected from the group consisting of (meth)acrylamide, N-substituted (meth)acrylamide, octyl (meth)acrylate, nonylphenol ethoxylate (meth)acrylate, isononyl (meth)acrylate, 1,6-hexanediol (meth)acrylate, isobornyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, β-carboxyethyl (meth)acrylate, isobutyl (meth)acrylate, cycloaliphatic epoxides, α-epoxides, 2-hydroxyethyl (meth)acrylate, (meth)acrylonitrile, maleic anhydride, itaconic acid, isodecyl (meth)acrylate, dodecyl (meth)acrylate, n-butyl (meth)acrylate, methyl ... The polymerizable composition may be, comprise, consist essentially of, or consist of a reaction product of one or more monomers, including, but not limited to, acrylate, hexyl (meth)acrylate, (meth)acrylic acid, N-vinyl caprolactam, stearyl (meth)acrylate, hydroxy-functional caprolactone ester (meth)acrylate, octadecyl (meth)acrylate, isooctyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxymethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxyisopropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyisobutyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, combinations thereof, and the like. In other embodiments, the acrylic can be, comprise, consist essentially of, or consist of one or more of (meth)acrylated urethane (i.e., urethane (meth)acrylate), (meth)acrylated epoxy (i.e., epoxy (meth)acrylate), (meth)acrylated polyester (i.e., polyester (meth)acrylate), (meth)acrylated (meth)acrylic, (meth)acrylated silicone, (meth)acrylated amine, (meth)acrylated amide; (meth)acrylated polysulfone; (meth)acrylated polyester, (meth)acrylated polyether (i.e., polyether (meth)acrylate), vinyl (meth)acrylate, and (meth)acrylated oil.

[0031] In various embodiments, the polyester can be, comprise, consist essentially of, or consist of any polyester known in the art. For example, the polyester can be linear or branched. Useful polyesters include the esterification products of aliphatic or aromatic dicarboxylic acids, polyols, diols, aromatic or aliphatic cyclic anhydrides, and cyclic alcohols. Non-limiting examples of suitable alicyclic polycarboxylic acids include tetrahydrophthalic acid, hexahydrophthalic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 4-methylhexahydrophthalic acid, endomethylenetetrahydrophthalic acid, tricyclodecanedicarboxylic acid, endethylenehexahydrophthalic acid, camphoric acid, cyclohexanetetracarboxylic acid, and cyclobutanetetracarboxylic acid. The alicyclic polycarboxylic acids can be used not only in the cis-form but also in the trans-form, and as mixtures of both forms. Further non-limiting examples of suitable polycarboxylic acids include aromatic and aliphatic polycarboxylic acids, such as phthalic acid, isophthalic acid, terephthalic acid, halogenophthalic acids (e.g., tetrachlorophthalic or tetrabromophthalic acid), adipic acid, glutaric acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, trimellitic acid, and pyromellitic acid. Combinations of polyacids, such as combinations of polycarboxylic acids and alicyclic polycarboxylic acids, may also be suitable. Combinations of polyols may also be suitable. Non-limiting examples of suitable polyesters include branched copolyester polymers. Branched copolyester polymers and methods for their preparation may be suitable, as described in U.S. Pat. No. 6,861,495, incorporated herein by reference. Monomers with multifunctional groups, such as AxBy (x, y = 1 to 3 (independently)) monomers, such as those with one carboxyl group and two hydroxyl groups, two carboxyl groups and one hydroxyl group, one carboxyl group and three hydroxyl groups, or three carboxyl groups and one hydroxyl group, can be used to create branched structures. Non-limiting examples of such monomers include 2,3-dihydroxypropionic acid, 2,3-dihydroxy-2-methylpropionic acid, 2,2-dihydroxypropionic acid, and 2,2-bis(hydroxymethyl)propionic acid. Polyesters can be conventionally polymerized from a monomer mixture containing a chain extender selected from the group consisting of hydroxycarboxylic acids, lactones of hydroxycarboxylic acids, and combinations thereof, and one or more branching monomers. Suitable hydroxycarboxylic acids include glycolic acid, lactic acid, 3-hydroxypropionic acid, 3-hydroxybutyric acid, 3-hydroxyvaleric acid, and hydroxypivalic acid. Suitable lactones include caprolactone, valerolactone, and the corresponding lactones of hydroxycarboxylic acids (e.g., 3-hydroxypropionic acid, 3-hydroxybutyric acid, 3-hydroxyvaleric acid, and hydroxypivalic acid). In certain embodiments, caprolactone can be used. In embodiments, branched copolyester polymers can be produced by polymerizing a monomer mixture containing a chain extender and a hyperbranched monomer in one step, or by first polymerizing the hyperbranched monomer and then polymerizing the chain extender. It should be understood that branched copolyester polymers can be formed from an acrylic core with the above-described extender monomers.

[0032] In various embodiments, resins including acrylic, polyester, or combinations thereof are used in amounts of about 10% to about 40%, about 15% to about 35%, or about 20% to about 30%, by weight based on the total weight percent of the composition. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of the recited values ​​and therebetween, are expressly contemplated for use herein.

[0033] Hydroxyl-functional resins: The hydroxyl-functional resin is not particularly limited and may be any known in the art. In various embodiments, the resin can be, comprise, consist essentially of, or consist of aliphatic or aromatic dicarboxylic acids, polyols, diols, aromatic or aliphatic cyclic anhydrides, and cyclic alcohols. Non-limiting examples of suitable cycloaliphatic polycarboxylic acids include tetrahydrophthalic acid, hexahydrophthalic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 4-methylhexahydrophthalic acid, endomethylenetetrahydrophthalic acid, tricyclodecanedicarboxylic acid, endethylenehexahydrophthalic acid, camphoric acid, cyclohexanetetracarboxylic acid, and cyclobutanetetracarboxylic acid. The cycloaliphatic polycarboxylic acids can be used not only in the cis-form but also in the trans-form, and as mixtures of both forms. Further non-limiting examples of suitable polycarboxylic acids include aromatic and aliphatic polycarboxylic acids, such as phthalic acid, isophthalic acid, terephthalic acid, halogenophthalic acids (e.g., tetrachlorophthalic or tetrabromophthalic acid), adipic acid, glutaric acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, trimellitic acid, and pyromellitic acid. Combinations of polyacids, such as combinations of polycarboxylic acids and alicyclic polycarboxylic acids, may also be suitable. Combinations of polyols may also be suitable. Non-limiting examples of suitable polyhydric alcohols include ethylene glycol, propanediol, butanediol, hexanediol, neopentyl glycol, diethylene glycol, cyclohexanediol, cyclohexanedimethanol, trimethylpentanediol, ethylbutylpropanediol, ditrimethylolpropane, trimethylolethane, trimethylolpropane, glycerol, pentaerythritol, dipentaerythritol, polyethylene glycol, and polypropylene glycol. If desired, monohydric alcohols, such as butanol, octanol, lauryl alcohol, ethoxylated or propoxylated phenols, and the like, may also be included with the polyhydric alcohol. Alternatively, low-molecular-mass polyols, e.g., polyhydric alcohols, defined by empirical and structural formulas, can be used. In other embodiments, oligomeric or polymeric polyols, e.g., having a number-average molar mass of, for example, up to 8,000, alternatively up to 5,000, or alternatively up to 2,000, and / or corresponding hydroxyl-functional polyethers, polyesters, or polycarbonates, for example, are used. In various embodiments, the hydroxyl-functional resin is used in an amount of about 10% to about 50%, about 10% to about 40%, about 12% to about 30%, or about 15% to about 25%, by weight percent based on the total weight percent of the composition. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of the recited values ​​and therebetween, are expressly contemplated for use herein.

[0034] The compositions of the present disclosure may include a crosslinker. The term "crosslinker" refers to a component having "crosslinkable functional groups," which are functional groups located on each molecule of the compound, oligomer, polymer, polymer backbone, side chains from the polymer backbone, terminal positions on the polymer backbone, or combinations thereof, that can crosslink with crosslinkable functional groups to produce a coating in the form of a crosslinked structure (during the curing process). Those skilled in the art will recognize that certain combinations of crosslinkable and crosslinkable functional groups are excluded because they cannot crosslink to produce a film-forming crosslinked structure.

[0035] Isocyanate Crosslinker: The isocyanate crosslinking agent is not particularly limited and may be any known in the art. In various embodiments, the isocyanate crosslinking agent may be, comprise, consist essentially of, or consist of one or more isocyanates, for example, but not limited to, aromatic, aliphatic, or alicyclic di-, tri-, or tetra-isocyanates, such as polyisocyanates having isocyanurate structural units, such as the isocyanurate of hexamethylene diisocyanate and the isocyanurate of isophorone diisocyanate; an adduct of two molecules of a diisocyanate, such as hexamethylene diisocyanate, and a diol, such as ethylene glycol; a uretidione of hexamethylene diisocyanate; a uretidione of isophorone diisocyanate or isophorone diisocyanate; or an adduct of trimethylolpropane and m-tetramethylxylene diisocyanate. In various embodiments, oligomers based on isocyanates, such as hexamethylene diisocyanate (HDI), diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), or toluidine diisocyanate (TDI), such as isocyanurates, biurets, allophanates, and adducts of the above isocyanates with polyhydric alcohols, and mixtures thereof, can be used. These can be reacted with polyols, such as OH-containing polyesters, polyethers, acrylates, and polyurethanes, and mixtures thereof, which may be solvent-based, solventless, or water-reducible. In various embodiments, monofunctional isocyanates are contemplated for use herein, as selected by those skilled in the art. In other embodiments, blocked isocyanates are contemplated for use herein, as selected by those skilled in the art. In various embodiments, the isocyanate crosslinker is used in an amount of about 3 to about 6, or about 3, 4, 5, or 6 weight percent based on the total weight percent of the composition. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of and therebetween, are expressly contemplated for use herein.

[0036] Optional crosslinker: In various embodiments, no isocyanate crosslinker is used and a melamine crosslinker is used. Alternatively, both an isocyanate crosslinker and a melamine crosslinker can be used. In various embodiments, this optional crosslinker can be, comprise, consist essentially of, or consist of any melamine crosslinker known in the art.

[0037] The melamine resin may be partially or fully etherified with one or more alcohols, such as methanol or butanol. A non-limiting example is hexamethoxymethyl melamine. Non-limiting examples of suitable melamine resins include monomeric melamine, polymeric melamine-formaldehyde resins, or combinations thereof. Monomeric melamines include low-molecular-weight melamines containing, on average, three or more methylol groups per triazine nucleus etherified with a C1-C5 monohydric alcohol, such as methanol, n-butanol, or isobutanol, an average condensation degree of up to about 2, and in certain embodiments, in the range of about 1.1 to about 1.8, and a proportion of mononuclear species of about 50% by weight or greater. In contrast, polymeric melamines have an average condensation degree greater than about 1.9. Some such suitable monomeric melamines include alkylated melamines, such as methylated, butylated, isobutylated melamine, and mixtures thereof. Many of these suitable monomeric melamines are commercially available. For example, Cytec Industries Inc. (West Patterson, NJ) offers Cymel® 301 (degree of polymerization 1.5, 95% methyl and 5% methylol), Cymel® 350 (degree of polymerization 1.6, 84% methyl and 16% methylol), 303, 325, 327, 370, and XW3106, all of which are monomeric melamines. Suitable polymeric melamines include a high-amino (partially alkylated, -N, -H) melamine known as Resimene® BMP5503 (molecular weight 690, polydispersity 1.98, 56% butyl, 44% amino) supplied by Solutia Inc. (St. Louis, Mo.), or Cymel® 1158, also available from Cytec Industries Inc. (West Patterson, NJ). Cytec Industries Inc. also supplies Cymel® 1130, 80% solids (degree of polymerization 2.5), and Cymel® 1133 (48% methyl, 4% methylol, and 48% butyl), both of which are polymeric melamines.In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of and between the recited values, are expressly contemplated for use herein.

[0038] The coating composition may include two or more crosslinkers having the same or different crosslinkable functional groups. Typical crosslinkable functional groups may include hydroxyl, thiol, isocyanate, thioisocyanate, acetoacetoxy, carboxyl, primary amine, secondary amine, epoxy, anhydride, ketimine, aldimine, orthoester, orthocarbonate, cyclic amide, or a combination thereof. In various embodiments, the optional crosslinker, such as a melamine crosslinker, is used in an amount of about 0 to about 30, about 5 to about 30, about 12 to about 25, or about 15 to about 20 weight percent, based on the total weight percent of the composition. In other embodiments, the amount is about 5 to about 25, about 10 to about 20, or about 10 to about 15 weight percent, based on the total weight percent of the composition. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of and between the recited values, are expressly contemplated for use herein.

[0039] In an exemplary embodiment, the coating composition comprises a melamine-formaldehyde resin having the trade name Cymel® 303, commercially available from Cytec Industries Inc. (West Patterson, NJ).

[0040] Optional pigments: Any pigment known in the art for use in coating compositions can be used in the coating composition. Non-limiting examples of suitable pigments include metal oxides, metal hydroxides, effect pigments including metal flakes, chromates such as lead chromate, sulfides, sulfates, carbonates, carbon black, silica, talc, china clay, phthalocyanine blue and green, organic red, organic maroon, pearlescent pigments, other organic pigments and dyes, and combinations thereof. Optionally, chromate-free pigments such as barium metaborate, zinc phosphate, aluminum triphosphate, and combinations thereof can also be used. Further non-limiting examples of suitable effect pigments include bright aluminum flakes, ultrafine aluminum flakes, medium-sized aluminum flakes, and bright medium-coarse aluminum flakes; mica flakes coated with titanium dioxide pigments, also known as pearlescent pigments; and combinations thereof. Non-limiting examples of suitable colored pigments include titanium dioxide, zinc oxide, iron oxide, carbon black, monoazo red toner, red iron oxide, quinacridone maroon, transparent red oxide, dioxazine carbazole violet, iron blue, indanthrone blue, chromium titanate, titanium yellow, monoazo permanent orange, ferrite yellow, monoazo benzimidazolone yellow, transparent yellow oxide, isoindoline yellow, tetrachloroisoindoline yellow, anthanthrone orange, lead chromate yellow, phthalocyanine green, quinacridone red, perylene maroon, quinacridone violet, pre-darkened chrome yellow, thioindigo red, transparent red oxide chips, molybdate orange, molybdate orange red, and combinations thereof.

[0041] As noted above, the coating composition may further comprise an extender pigment. While extender pigments are typically used to replace more costly pigments in coating compositions, the extender pigments contemplated herein may increase the shear viscosity of the coating composition compared to a coating composition that does not contain the extender pigment. Increasing the shear viscosity of the coating composition may improve the suitability of the coating composition for application to substrates using high-transfer-efficiency applicators. The extender pigment may have a particle size of about 0.01 to about 44 microns. The extender pigment may have a variety of configurations, including, but not limited to, nodular, platelet, acicular, and fibrous. Non-limiting examples of suitable extender pigments include chalk, barite, amorphous silica, fumed silica, diatomaceous silica, china clay, calcium carbonate, phyllosilicate (mica), wollastonite, magnesium silicate (talc), barium sulfate, kaolin, and aluminum silicate. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of and between the recited values, are expressly contemplated for use herein. The coating composition can include an extender pigment in an amount of about 0.1 to about 50, alternatively about 1 to about 20, alternatively about 1 to about 10 weight percent, based on the total weight of the coating composition. In certain embodiments, the coating composition includes magnesium silicate (talc), barium sulfate, or a combination thereof. In various embodiments, the inclusion of barium sulfate as an extender pigment results in a coating composition with a higher shear viscosity compared to the inclusion of talc as an extender pigment. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of the recited values ​​and therebetween, are expressly contemplated for use herein.

[0042] In various embodiments, the optional pigment is selected from Pigment Yellow 213, PY151, PY93, PY83, Pigment Red 122, PR168, PR254, PR179, Pigment Red 166, Pigment Red 48:2, Pigment Violet 19, Pigment Blue 15:1, Pigment Blue 15:3, Pigment Blue 15:4, Pigment Green 7, Pigment Green 36, Pigment Black 7, or Pigment White 6, and combinations thereof.

[0043] Organic solvents: The composition may also contain an organic solvent. Non-limiting examples of suitable organic solvents include aromatic hydrocarbons such as toluene and xylene; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, and diisobutyl ketone; esters such as ethyl acetate, n-butyl acetate, and isobutyl acetate, and combinations thereof. In embodiments, the evaporation rate of the solvent may affect the suitability of the coating composition for printing. Certain co-solvents may be incorporated into the coating composition with high or low evaporation rates, thereby increasing or decreasing the evaporation rate of the coating composition. In various embodiments, the organic solvent content is greater than about 50%, alternatively greater than 60%, alternatively greater than 70%, alternatively greater than 80%, or alternatively greater than 90% by weight, based on the total weight of the liquid carrier of the coating composition. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of and therebetween, are expressly contemplated for use herein.

[0044] At least one polyurea crystalline sag control agent: The composition also includes at least one polyurea crystalline sag control agent. The control agent is the reaction product of an amine and an isocyanate. Both the amine and the isocyanate are not particularly limited and may be any known in the art or described above. For example, the amine may be a primary or secondary amine. The amine typically contains hydroxyl and / or ether groups. In various embodiments, the amine is a mono-, di-, tri-, or polyamine. In various embodiments, the use of a di-, tri-, and / or polyamine requires the use of a monofunctional isocyanate. The at least one polyurea crystal sag control agent has a melting point of about 50° C. to about 150° C. In various embodiments, the melting point is about 55 to about 145° C., about 60 to about 140° C., about 65 to about 135° C., about 70 to about 130° C., about 75 to about 125° C., about 80 to about 120° C., about 85 to about 115° C., about 90 to about 110° C., about 95 to about 105° C., about 100 to about 105° C., about 50 to about 100° C., about 55 to about 95° C., about 60 to about 90° C., about 6 ...15° C., about 90 to about 110° C., about 95 to about 105° C., about 100 to about 105° C., about 100 to about 105° C., about 100 to about 105° C., about 10 5 to about 85, about 70 to about 80, about 70 to about 75, about 50 to about 120, about 55 to about 115, about 60 to about 110, about 65 to about 105, about 70 to about 100, about 75 to about 95, about 80 to about 90, about 80 to about 85, about 120 to about 150, about 125 to about 145, about 130 to about 140, or about 130 to about 135° C. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of and between the recited values, are expressly contemplated for use herein. In various embodiments, the at least one polyurea crystalline sag control agent is present in an amount of from about 0.1 to about 4 weight percent, based on the total weight of the coating composition. In other embodiments, the at least one polyurea crystalline sag control agent is present in an amount of from about 0.2 to about 3.9, from about 0.3 to about 3.8, from about 0.4 to about 3.7, from about 0.5 to about 3.6, from about 0.6 to about 3.5, from about 0.7 to about 3.4, from about 0.8 to about 3.3, from about 0.9 to about 3.2, from about 1 to about 3.1, from about 1.1 to about 3, from about 1.2 to about 2.9, from about 1.3 to about 2.8, from about 1.4 to about 2.7, from about 1.5 to about 2.6, from about 1.6 to about 2.5, from about 1.7 to about 2.4, from about 1.8 to about 2.3, from about 1.9 to about 2.2, or from about 2 to about 2.1 weight percent, based on the total weight of the coating composition. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of and between the recited values, are expressly contemplated for use herein.

[0045] In one embodiment, the at least one polyurea crystal sag control agent can be described as opaque and, in various non-limiting embodiments, may be as described in U.S. Patent No. 4,311,622, the disclosure of which is expressly incorporated herein by reference in its entirety. In one embodiment, the at least one polyurea crystal sag control agent is anisotropic colloidal polyurea crystals, such as the reaction product of an organic diisocyanate and benzylamine. In another embodiment, the at least one polyurea crystal sag control agent can be described as transparent and in various non-limiting embodiments may be as described in U.S. Patent No. 4,677,028 and / or U.S. Patent No. 7,656,151, the disclosures of which are expressly incorporated by reference herein in their entireties. In one embodiment, the at least one polyurea crystal sag control agent is anisotropic colloidal polyurea crystals, which are the reaction product of an amine and an organic tri- or poly-isocyanate. In another embodiment, the at least one polyurea crystalline sag control agent can be described as potent and, in various non-limiting embodiments, can be as described in U.S. Patent No. 7,851,530, the disclosure of which is expressly incorporated herein by reference in its entirety. In one embodiment, the at least one polyurea crystalline sag control agent is the reaction product of one or more optically active organic amines and one or more di- or polyisocyanates (e.g., those derived from diisocyanates containing 3 to 20 carbons).

[0046] In one embodiment, the isocyanate is an organic diisocyanate, the amine is benzylamine, and the melting point is about 120°C to about 150°C. In another embodiment, the at least one polyurea crystalline sag control agent is present in an amount of about 0.1 to about 1.75 weight percent, based on the total weight of the coating composition. For example, the amount may be about 0.2 to about 1.7, about 0.3 to about 1.6, about 0.4 to about 1.5, about 0.5 to about 1.4, about 0.6 to about 1.3, about 0.7 to about 1.2, about 0.8 to about 1.1, or about 0.9 to about 1 weight percent, based on the total weight of the coating composition. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of and between the recited values, are expressly contemplated for use herein. In another embodiment, the organic diisocyanate is hexamethylene diisocyanate. In another embodiment, the isocyanate is an organic triisocyanate and / or organic polyisocyanate having a melting point of about 50°C to about 100°C. In another embodiment, the at least one polyurea crystalline sag control agent is present in an amount of about 0.1 to about 2.5 weight percent, based on the total weight of the coating composition. For example, the amount may be about 0.2 to about 2.4, about 0.3 to about 2.3, about 0.4 to about 2.2, about 0.5 to about 2.1, about 0.6 to about 2, about 0.7 to about 1.9, about 0.8 to about 1.8, about 0.9 to about 1.7, about 1 to about 1.6, about 1.1 to about 1.5, about 1.2 to about 1.4, or about 1.3 to about 1.4 weight percent, based on the total weight of the coating composition. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of and between the recited values, are expressly contemplated for use herein. In another embodiment, the isocyanate is an organic diisocyanate, triisocyanate, and / or polyisocyanate, the amine is optically active, and has a melting point of about 50°C to about 120°C. Those skilled in the art will recognize that the term optically active describes chiral amines, e.g., the R or S enantiomer of a chiral amine, and not a mixture of the R and S enantiomers of a chiral amine. In one embodiment, the at least one polyurea crystalline sag control agent is present in an amount of about 0.1 to about 2 wt.%, based on the total weight of the coating composition. This amount may be, for example, about 0.2 to about 1.9, about 0.3 to about 1.8, about 0.4 to about 1.7, about 0.5 to about 1.6, about 0.6 to about 1.5, about 0.7 to about 1.4, about 0.8 to about 1.3, about 0.9 to about 1.2, or about 1 to about 1.1 wt.%, based on the total weight of the coating composition. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of and between the recited values, are expressly contemplated for use herein.

[0047] In one embodiment, the reactants are: [ka] In another embodiment, the reactants are: [ka] In another embodiment, the reactants are: [ka]

[0048] Additional optional ingredients: The coating composition may include various components, such as binders, dyes, rheology modifiers, carriers, catalysts, conventional additives, or combinations thereof. Conventional additives include, but are not limited to, dispersants, antioxidants, UV stabilizers and absorbers, surfactants, wetting agents, leveling agents, antifoaming agents, anti-cratering agents, or combinations thereof. In embodiments, the coating composition is suitable for application to a substrate using a high transfer efficiency applicator, provided that the coating composition includes certain components and / or contains certain components in certain amounts / ratios.

[0049] In various embodiments, the coating composition may further comprise a dye. Non-limiting examples of suitable dyes include triphenylmethane dyes, anthraquinone dyes, xanthene and related dyes, azo dyes, reactive dyes, phthalocyanine compounds, quinacridone compounds, and optical brighteners, and combinations thereof. The coating composition may comprise the dye in an amount of about 0.01 to about 5, alternatively about 0.05 to about 1, alternatively about 0.05 to about 0.5, by weight, based on the total weight of the coating composition. In certain embodiments, the coating composition comprises a 10% black dye solution, such as Sol. Orasol Negro RL. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of the values ​​recited above, are expressly contemplated for use herein.

[0050] The term "binder" refers to the film-forming component of a coating composition. Typically, a binder can include polymers, oligomers, or combinations thereof that are essential for forming a coating having desired properties, such as hardness, protection, and adhesion. Additional components, such as carriers, pigments, catalysts, rheology modifiers, antioxidants, UV stabilizers and absorbers, leveling agents, antifoaming agents, anti-cratering agents, or other conventional additives, may not be included in the term "binder" unless any of these additional components are film-forming components of the coating composition. One or more of these additional components can be included in the coating composition. In certain embodiments, the binder comprises a polymer. The coating composition can include the binder in an amount of about 5 to about 70 weight percent, alternatively about 10 to about 50 weight percent, or alternatively about 15 to about 25 weight percent, based on the total weight of the coating composition. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of the values ​​recited above, are expressly contemplated for use herein.

[0051] As noted above, the coating composition may further include a catalyst. The coating composition may further include a catalyst to shorten the cure time and enable the coating to cure at ambient temperatures. Ambient temperature typically refers to a temperature ranging from about 18°C ​​to about 35°C. Non-limiting examples of suitable catalysts include organometallic salts such as dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dichloride, dibutyltin dibromide, zinc naphthenate; triphenylboron, tetraisopropyl titanate, triethanolamine titanate chelate, dibutyltin dioxide, dibutyltin dioctoate, tin octoate, aluminum titanate, aluminum chelate, zirconium chelate, hydrocarbon phosphonium halides such as ethyltriphenylphosphonium iodide, and other such phosphonium salts and other catalysts, or combinations thereof. Non-limiting examples of suitable acid catalysts include carboxylic acids, sulfonic acids, phosphoric acids, or combinations thereof. In some embodiments, the acid catalyst can include, for example, acetic acid, formic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, p-toluenesulfonic acid, phosphoric acid, or a combination thereof. The coating composition can include the catalyst in an amount of about 0.01 to about 5, alternatively about 0.05 to about 1, alternatively about 0.05 to about 0.5 weight percent, based on the total weight of the coating composition. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of and between the recited values, are expressly contemplated for use herein.

[0052] As noted above, the coating composition may further include conventional additives. The coating composition may further include an ultraviolet stabilizer. Non-limiting examples of such ultraviolet stabilizers include ultraviolet absorbers, screeners, quenchers, and hindered amine light stabilizers. Antioxidants may also be added to the coating composition. Typical ultraviolet stabilizers include benzophenones, triazoles, triazines, benzoates, hindered amines, and mixtures thereof. Blends of hindered amine light stabilizers, such as Tinuvin® 328 and Tinuvin® 123, all commercially available under the trade name Tinuvin® from Ciba Specialty Chemicals (Tarrytown, New York), can be used. Non-limiting examples of suitable ultraviolet absorbers include hydroxyphenylbenzotriazoles, such as 2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole, 2-(2-hydroxy-3,5-di-tert-amyl-phenyl)-2H-benzotriazole, 2[2-hydroxy-3,5-di(1,1-dimethylbenzyl)phenyl]-2H-benzotriazole, the reaction product of 2-(2-hydroxy-3-tert-butyl-5-methylpropionate)-2H-benzotriazole with polyethylene ether glycol having a weight average molecular weight of 300, 2-(2-hydroxy-3-tert-butyl-5-isooctylpropionate)-2H-benzotriazole; hydroxyphenyl s-triazines, such as 2-[4((2,-hydroxy-3-dodecyloxy / tridecyloxypropyl)-oxy)-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-[4(2-hydroxy-3-(2-ethylhexyl)-oxy)-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)1,3,5-triazine, 2-(4-octyloxy-2-hydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine; hydroxybenzophenone UV absorbers, such as 2,4-dihydroxybenzophenone, 2-hydroxy-4-octyloxybenzophenone, and 2-hydroxy-4-dodecyloxybenzophenone.

[0053] Non-limiting examples of suitable hindered amine light stabilizers include N-(1,2,2,6,6-pentamethyl-4-piperidinyl)-2-dodecylsuccinimide, N(1-acetyl-2,2,6,6-tetramethyl-4-piperidinyl)-2-dodecylsuccinimide, N-(2-hydroxyethyl)-2,6,6,6-tetramethylpiperidin-4-ol-succinic acid copolymer, 1,3,5-triazine-2,4,6-triamine, N,N'"-[1,2-ethoxyethyl] ... N,N'"-dibutyl-N',N'"-bis(1,2,2,6,6-pentamethyl-4-piperidinyl)], poly-[[6-[1,1,3,3-tetramethylbutyl)-amino]-1,3,5-triazine-2,4-diyl][2,2,6,6-tetramethylbutyl]-amino]-1,3,5-triazine-2-yl]imino]-3,1-propanediyl]]bis[N,N'"-dibutyl-N',N'"-bis(1,2,2,6,6-pentamethyl-4-piperidinyl)], methylpiperidinyl)-imino]-1,6-hexane-diyl[(2,2,6,6-tetramethyl-4-piperidinyl)-imino]), bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidinyl)[ 3,5 bis(1,1-dimethylethyl-4-hydroxy-phenyl)methyl]butylpropanedioate, 8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro(4,5)decane-2,4-dione, and dodecyl / tetradecyl-3-(2,2,4,4-tetramethyl-2l-oxo-7-oxa-3,20-diazaldispiro(5.1.11.2)henicosan-20-yl)propionate.

[0054] Non-limiting examples of suitable antioxidants include tetrakis[methylene(3,5-di-tert-butylhydroxyhydrocinnamate)]methane, octadecyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, tris(2,4-di-tert-butylphenyl)phosphite, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, and benzenepropanoic acid, 3,5-bis(1,1-dimethyl-ethyl)-4-hydroxy-C7-C9 branched alkyl ester. In certain embodiments, antioxidants include hydroperoxide decomposers such as Sanko® HCA (9,10-dihydro-9-oxa-10-phosphenanthrene-10-oxide), triphenyl phosphate and other organophosphorus compounds such as Irgafos® TNPP from Ciba Specialty Chemicals, Irgafos® 168 from Ciba Specialty Chemicals, Ultranox® 626 from GE Specialty Chemicals, Mark PEP-6 from Asahi Denka, Mark HP-10 from Asahi Denka, Irgafos® P-EPQ from Ciba Specialty Chemicals, Ethanox 398 from Albemarle, Weston 618 from GE Specialty Chemicals, Irgafos® 12 from Ciba Specialty Chemicals, Irgafos® 38 from Ciba Specialty Chemicals, GE Specialty Chemicals, Examples of suitable anti-inflammatory agents include Ultranox® 641 from Dover Chemicals, and Doverphos® S-9228 from Dover Chemicals.

[0055] The coating composition may further contain other additives known in the art for use in coating compositions. Non-limiting examples of such additives include wetting agents, leveling agents, and flow control agents, such as Resiflow® S (polybutyl acrylate), BYK® 320 and 325 (high molecular weight polyacrylates), and BYK® 347 (polyether-modified siloxane), leveling agents based on (meth)acrylic homopolymers; rheology control agents; thickeners, such as partially crosslinked polycarboxylic acids or polyurethanes; and defoamers. Other additives may be used in conventional amounts well known to those skilled in the art. In embodiments, the wetting agents, leveling agents, flow control agents, and surfactants of the coating composition may affect the surface tension of the coating composition and, therefore, the suitability of the coating composition for printing. Certain wetting agents, leveling agents, flow control agents, and surfactants may be incorporated into the coating composition to increase or decrease the surface tension of the coating composition.

[0056] The coating compositions may have a solids content of about 5 to about 90, alternatively 5 to about 80, alternatively about 15 to about 70 weight percent. Solids content can be determined according to ASTM D2369-10. In certain embodiments, higher solids content may be desirable for coating compositions because the coating compositions are not atomized using conventional atomizing equipment. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of the values ​​recited above, are expressly contemplated for use herein.

[0057] The coating composition can be substantially free of dyes. As used herein, the term "substantially" means that the coating composition can contain a small amount of dye and the color and / or properties of the coating composition will not be affected by the addition of the small amount of dye and still be considered substantially free of dyes. In embodiments, the substantially free coating composition contains 5% by weight or less, alternatively 1% by weight or less, or alternatively 0.1% by weight or less. In various embodiments, the composition is free of clay and silica. The term "free of" may describe a composition containing less than 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.5, or 0.1% by weight of clay and silica, based on the total weight of the composition. Alternatively, the composition may be completely free of clay or silica. The clay is not particularly limited and may be clay particles surface-functionalized with a quaternary amine. Similarly, the silica is not particularly limited and may be an organophilic phyllosilicate, amorphous silica, such as CAS:92797-60-9, AEROSIL R-805 VV90, and combinations thereof.

[0058] In various embodiments, the method further includes a step of curing the coating composition on the substrate, wherein the high transfer efficiency applicator includes a plurality of nozzles, and the applying step is further defined as applying the coating composition in a plurality of lines onto the substrate through the nozzles, and wherein the coating composition, after the curing step, is free of visible defects due to incomplete flow and leveling from individual nozzle lines. In another embodiment, the method further comprises curing the coating composition on the substrate, wherein the high transfer efficiency applicator comprises a plurality of nozzles, and the applying step is further defined as applying the coating composition through the nozzles onto the substrate in a plurality of lines in a direction (X) along the substrate, each line partially overlapping an adjacent line to form overlapping regions and non-overlapping regions, and the overlapping regions have a visual smoothness such that the variation in thickness of the overlapping regions compared to the thickness of the non-overlapping regions measured after the curing step over a distance of 5 mm measured perpendicular to the direction (X) is less than about 1 micron. In various embodiments, the high transfer efficiency applicator includes a nozzle having a diameter, and applying the coating composition to a substrate through the high transfer efficiency applicator minimizes nozzle clogging, and the coating composition does not include components having an average particle size greater than about 10% of the nozzle diameter. The nozzle and nozzle diameter can be any of those described herein or known in the art.

[0059] In one embodiment, A. Resin is an OH functional acrylic resin with Mw of 5500 and hydroxy content of 97 mg KOH / g; B. Melamine crosslinker Methylated, isobutylated melamine formaldehyde resin; Methylated, imino type (triether) melamine formaldehyde resin, Includes; C. The optional pigment is a 20% carbon black dispersion; D. The organic solvent is an aromatic hydrocarbon naphthalene-depleted solvent; E. at least one polyurea crystalline sag control agent is a reaction product of an amine and an isocyanate, where the isocyanate is an organic diisocyanate, triisocyanate, and / or polyisocyanate, the amine is optically active, and the control agent has a melting point of from about 50°C to about 120°C; The coating composition further comprises a hydroxylated acrylic polyol having a modified hydroxy content of 4.5%.

[0060] In another embodiment, A. Resin is an OH-functional branched acrylic resin with Mw of 34,500 and hydroxy content of 54 mg KOH / g; B. Melamine crosslinker Methylated, isobutylated melamine formaldehyde resin; Methylated, imino type (triether) melamine formaldehyde resin, Includes; C. The optional pigment is a 20% carbon black dispersion; D. The organic solvent is a naphthalene-free aromatic hydrocarbon solvent; E. at least one polyurea crystal sag control agent is a reaction product of an amine and an isocyanate, where the isocyanate is an organic diisocyanate, the amine is benzylamine, and the control agent has a melting point of about 120°C to about 150°C; The coating composition further comprises a hydroxylated acrylic polyol having a modified hydroxy content of 4.5%.

[0061] Sag Rating: In various embodiments, the coating composition has a wet film thickness of at least about 30 microns without visible sag when measured at about 45 degrees. For example, the wet film thickness may be about 30 microns to about 150 microns, or about 40 to about 120 microns without visible sag when measured at about 45 degrees. In other embodiments, the wet film thickness may be about 35 to about 145, about 40 to about 140, about 45 to about 135, about 40 to about 130, about 45 to about 125, about 50 to about 120, about 55 to about 115, about 60 to about 110, about 65 to about 105, about 70 to about 100, about 75 to about 95, about 80 to about 90, or about 85 to about 90 microns. In various non-limiting embodiments, all values ​​and ranges of values, both whole and partial, inclusive of and between the recited values, are expressly contemplated for use herein.

[0062] The following steps are commonly used to assess sag: The substrate panel is oriented horizontally prior to coating application; Using a high transfer efficiency applicator, three continuous stripes of coating composition are applied to the horizontal substrate such that the compositions overlap to provide a continuous coating surface with a target wet film thickness (typically 30 microns or greater) and a coated substrate width of approximately 150 mm. After applying the composition, the panel is tilted so that the coating substrate width of about 150 mm is at an angle of about 20 to about 45 degrees from the horizontal, for example, as shown in FIG. 2B. With the panel angle maintained the same, after about 10 minutes at room temperature, the panel is baked at about 140° C. for about 30 minutes. If sag is present, it is visually assessed for evidence of dripping at the bottom edge of the coating, for example as shown in FIGS. 4A, 4B and 5.

[0063] If present, the visibility of the nozzle lines is observed as fine lines parallel to each other as well as in the application direction, with the same spacing (approximately 1 mm) as adjacent nozzles of the applicator, as shown, for example, in Figure 3. If present, the visibility of stripe overlap is visually assessed in areas where the coating was applied in successive application passes. As shown in Figures 3-4, thickness variations of as little as 1 micron over a distance of 5 mm parallel to the application direction can be seen to result in visible stripe overlap.

[0064] Use of the coating compositions of the present invention can reduce or eliminate nozzle clogging. For example, high-transfer-efficiency "stream-on-demand" or "drop-on-demand" applicators typically contain an array of fine-diameter nozzles, each with a nozzle diameter of about 20 microns to 200 microns. For reliable fluid jetting, it is typically expected that the particle size of any component of the coating composition must be about 10% or less of the nozzle diameter. While some components of the coating composition may have an average size that meets the above criteria, the presence of small amounts of oversized particles will, over time, result in nozzle clogging. The result is either a partially clogged nozzle, which can produce misdirected droplets or streams, or a completely clogged nozzle, which prevents fluid from being ejected. In either case, this results in coating defects. Clogging can be assessed in two ways: (1) clogging of a filter installed before the applicator, and (2) microscopic examination of debris in the nozzle following a missing line during coating application.

[0065] While well-known coating appearance characteristics such as gloss, image clarity, and orange peel can be quantified with various instruments, this does not apply to nozzle line and stripe overlap visibility. Coatings applied with high transfer efficiency applicators have high gloss, high image clarity, and no orange peel, but may still have visible nozzle line and stripe overlap defects. As shown schematically in FIG. 3C, item 20 represents lines of paint deposited from a single nozzle parallel to the application direction. While the lines may be visible immediately after application, if sufficient flow and leveling do not occur, they may still be visible after the coating cures, resulting in an uneven and generally undesirable coating appearance. Typically, nozzle line visibility gives a striped appearance, with the distance between the visible lines being the same as the spacing of the nozzles on the applicator. Stripe overlap defects are also parallel to the application direction, but this defect is not related to the spacing of the applicator nozzles. These defects are only present where adjacent stripes of coating overlap, and are visible across lengths on the scale of 5-10 mm perpendicular to the coating direction. While these defects are typically assessed by comparison with a control coating printed at a low viscosity and without rheology control agents, surface profile measurements (Figure 4A) demonstrate that defects are visible when the height difference between high and low areas is greater than 1-2 microns. [Example]

[0066] A series of sag control agent and coating compositions were prepared and evaluated as follows: After formation, each of the compositions was evaluated to measure various physical properties, which are also described below.

[0067] Synthesis of various sag control agents: Example 1: TSCA-1 At room temperature, 80.7 parts of resin solution (polyhydroxyacrylic resin, Mw approx. 7000, in aromatic 100 solvent), 0.9 parts of 3-methoxypropylamine, and 12 parts of butyl acetate were introduced into a reactor. With vigorous stirring, 1.9 parts of aliphatic polyisocyanate (Desmodur N 3600) dissolved in 4.5 parts of butyl acetate was added. Stirring was continued for 15 minutes, then reduced speed for an additional 10 minutes. This reaction system can be generally represented as follows: [ka] Here, the difference between TSCA-1 and TSCA-2 is the triisocyanate versus isocyanate fatty chain length distribution (reflected in the component molecular weights below). The melting points listed are from the product literature; actual melting points were not measured for this example.

[0068] Example 2: TSCA-2 At room temperature, 80.7 parts of resin solution (polyhydroxyacrylic resin, Mw approx. 7000, in aromatic 100 solvent), 0.8 parts of 3-methoxypropylamine, and 12 parts of butyl acetate were introduced into a reactor. With vigorous stirring, 2 parts of an aliphatic polyisocyanate (Desmodur N 3390) dissolved in 4.5 parts of butyl acetate was added. Stirring was continued for 15 minutes and then reduced for an additional 10 minutes. [Table 1] [Table 2]

[0069] Synthesis of various coating compositions: Example 3 The coating compositions are prepared using the materials described immediately below. After formation, the coating compositions are evaluated to measure viscosity, nozzle clogging, sag, nozzle line visibility, and overlap visibility. [Table 3] TIFF2022162553000008.tif61160

[0070] Above and below, throughout these examples, each "+" is a positive indicator of subjectively superior performance, as would be understood and appreciated by one of ordinary skill in the art. Each "-" is a negative indicator of subjectively inferior performance, as would be understood and appreciated by one of ordinary skill in the art. When more than one "+" or "-" symbol is used, this means better or worse performance, respectively, as would be understood and appreciated by one of ordinary skill in the art. Viscosity was evaluated using ASTM 2196. Additionally, nozzle clogging, sag, nozzle line visibility, and overlap visibility are evaluated using the methods described above.

[0071] Example 4 Additional coating compositions are prepared using the materials described immediately below. After formation, the coating compositions are evaluated to measure viscosity, nozzle clogging, sag, nozzle line visibility, and overlap visibility. [Table 4] TIFF2022162553000010.tif87160

[0072] Viscosity was evaluated using ASTM D2196. Additionally, nozzle clogging, sag, nozzle line visibility, and overlap visibility are evaluated using the methods described above.

[0073] Examples 5 to 11 Additional coating compositions are prepared using the materials described immediately below. After formation, the coating compositions are evaluated to measure nozzle clogging, sag, nozzle line visibility, and overlap visibility. [Table 5] TIFF2022162553000012.tif162164 *"NA" means it was not possible to measure due to severe nozzle clogging that prevented the coating from being applied.

[0074] Additionally, nozzle clogging, sag, nozzle line visibility, and overlap visibility are evaluated using the methods described above. In relation to the above, the materials are as follows: [Table 6]

[0075] Examples 5, 6, and 8 demonstrate that rheology control agents of the type commonly used in spray atomization to provide a desirable balance of sag, flow, and leveling cannot be used with high-transfer applicators of the type discussed herein due to severe nozzle clogging. For example, particles or agglomerates in the coating formulation may be large enough that they cannot pass through the small nozzles of high-transfer efficiency applicators. Examples 3, 7, 10, and 11 contain different types of sag control agents that result in either excellent (not observed at all) or only tolerable minor amounts of nozzle clogging. These examples demonstrate significant improvements in sag over the control Example 9 (no rheology control agent), while also providing different levels of benefit in terms of nozzle line and stripe overlap visibility. Because specific requirements for applying coatings to automotive bodies require different levels of sag resistance, these examples demonstrate the potential for tailoring the selection of SCA type and level to match overall appearance performance (balance of flow and leveling against sag). Example 4 contained a different SCA that exhibited severe clogging.

[0076] While at least one exemplary embodiment has been set forth in the foregoing detailed description, it should be understood that numerous variations exist. It should also be understood that the exemplary embodiment or embodiments are merely examples and are not intended to be limiting in scope, applicability, or configuration. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiments. It should be understood that various changes may be made in the function and arrangement of elements described in the exemplary embodiments without departing from the scope as set forth in the appended claims.

Claims

1. 1. A method for applying a one-part solvent-based coating composition to a substrate using a high transfer efficiency applicator to form a coating layer disposed on the substrate, the method comprising: providing the coating composition to the high transfer efficiency applicator; applying the coating composition to the substrate through the high transfer efficiency applicator to form the coating layer on the substrate, wherein volatile loss after application through the high transfer efficiency applicator is less than about 0.5% by weight, based on the total weight of the coating composition; Including, The coating composition comprises: A. a resin including acrylic, polyester, or a combination thereof; B. a melamine crosslinker; C. an optional pigment; D. an organic solvent; E. at least one polyurea crystalline sag control agent, the polyurea crystalline sag control agent being a reaction product of an amine and an isocyanate, having a melting point of from about 50° C. to about 150° C., and present in an amount of from about 0.1 to about 4 weight percent based on the total weight of said coating composition; Including, the coating composition has a wet film thickness of at least about 30 microns without visible sag when measured at about 45 degrees; method.

2. The method of claim 1, wherein the isocyanate is an organic diisocyanate, the amine is a benzylamine, and the melting point is from about 120°C to about 150°C.

3. The method of claim 2, wherein the at least one polyurea crystal sag control agent is present in an amount of about 0.1 to about 1.75 weight percent, based on the total weight of the coating composition.

4. The method of claim 3, wherein the organic diisocyanate is hexamethylene diisocyanate.

5. The method of claim 1, wherein the isocyanate is an organic triisocyanate and / or an organic polyisocyanate, and the melting point is from about 50°C to about 100°C.

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