PVF coil coating system

Abstract

A multilayer coating system for application by coil coating, spray, or spray-applied to an extruded metal substrate is described. The system includes a first layer applied over a substrate, wherein the first layer includes a first coating composition of a polyvinyl fluoride (PVF) resin component. The system also includes a second layer applied over the first layer, wherein the second layer includes a second coating composition of a PVF resin component. The first and second layers may independently include an additional fluorinated resin component. Methods of making the coating composition and coated articles are also described.

Description

PVF COIL COATING SYSTEMBACKGROUND OF THE INVENTION

[0001] Polymer coating compositions are routinely applied to substrates, especially metal substrates. Such coatings are used for a variety of reasons, including, for example, to protect the substrate from degradation because of exposure to the environment, to harsh chemicals, and the like, to beautify the substrate (e.g., to provide color, brightness, etc.), and / or to reflect light, among many other reasons.

[0002] Many such polymer coating compositions are applied on planar substrates that are subsequently formed into finished articles, including articles used as exterior building materials. In general, for a coating composition or system to be used as an exterior coating, the composition or system must demonstrate optimal or even superior formability, chemical resistance, long-term outdoor weathering, durability, and improved wear resistance. The coating must also maintain a suitable aesthetic appearance (gloss, color, and the like) over prolonged periods of exposure to exterior conditions, including sunlight, humidity, rain, harsh chemicals, and the like.

[0003] Coatings made from polyvinyl fluoride (PVF) have certain superior performance characteristics relative to conventional coatings used in exterior applications, being extremely stable and resistant to attack from a variety of chemical and energy stressors. Moreover, these coatings do not absorb UV light, and do not dissolve in any known solvents at room temperature. However, PVF coatings have generally been applied as extruded films for exterior architectural applications and have not been used as coil-applied coatings. Further, PVF -based coatings may demonstrate significant processing difficulties, including long production times and reduced line speed capability during coil coating operations.

[0004] Accordingly, there is a continuing need for PVF -based coil coatings that provide reduced production times and increased line speed capability, while having equal or improved performance characteristics relative to conventional coating systems used in exterior applications, including coil coatings.SUMMARY

[0005] The present invention provides a coating system for metal substrates. The coating system demonstrates optimal weather resistance, chemical resistance, flexibility, and impact resistance, and may be applied to a variety of metal substrates by various methods, including by spray application to a planar metal substrate or an extruded metal substrate (including aluminum substrates), or by a coil application process. Methods of making the coating composition and articles coated with the described coating system are also provided.

[0006] In one embodiment, the present description provides a multilayer coating system. In an aspect, the coating system includes a first layer and a second layer. The first layer is applied over a substrate and includes a first coating composition including at least about 5 to 20 percent by weight polyvinyl fluoride (PVF) resin component, based on the total weight of the first coating composition. The second layer is applied over the first layer and includes a second coating composition including at least 40 to 100 percent by weight of a polyvinyl fluoride (PVF) resin component, based on the total weight of the second coating composition. Optionally, the coating system also includes a third layer applied over the second layer.

[0007] In another embodiment, a method of making a coating composition including PVF resin component is described. The method includes steps of providing at least about 5 to 20 percent by weight of a polyvinyl fluoride (PVF) resin component and combining this resin component with other components to make a paint with particle size less than 20 pm. The process of combining the resin component with other components takes about 15 to 20 minutes for a 2L batch.

[0008] In yet another embodiment, articles coated with the coating system described herein are provided. The coated article includes a planar metal substrate and a coating system applied to the planar metal substrate. The coating system includes a first layer and a second layer. The first layer is applied over a substrate and includes a first coating composition including at least about 5 to 20 percent by weight polyvinyl fluoride (PVF) resin component, based on the total weight of the first coating composition. The second layer is applied over the first layer and includes a second coating composition including at least 40 to 100 percent by weight of a polyvinyl fluoride (PVF) resin component, based on the total weight of the second coating composition. Optionally, the coating system also includes a third layer applied over the second layer.

[0009] The above summary of the present invention is not intended to describe each disclosed embodiment or every implementation of the present invention. The description thatfollows more particularly exemplifies illustrative embodiments. In several places throughout the application, guidance is provided through lists of examples, which can be used in various combinations. In each instance, the recited list serves only as a representative group and should not be interpreted as an exclusive list.

[0010] The details of one or more embodiments of the invention are set for in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.SELECTED DEFINITIONS

[0011] Unless otherwise specified, the following terms as used herein have the meanings as provided below.

[0012] The term “component” refers to any compound that includes a particular feature or structure. Examples of components include compounds, monomers, oligomers, polymers, resins, and organic groups contained there.

[0013] The term “double bond” is non-limiting and refers to any type of double bond between any suitable atoms (e.g., C, O, N, etc.).

[0014] The term “triple bond” is non-limiting and refers to any type of triple bond between any suitable atoms.

[0015] The term “substantially free” of a particular compound or component means that the compositions described herein contain less than 5 percent by weight (based on the total weight of the composition) of the particular compound or component. The term “essentially free” of a particular component or compound means that the compositions described herein contain less than 2 parts by weight (based on the total weight of the composition) of the particular component or compound. The term “completely free” of a particular mobile compound means that the compositions of the present invention contain less than 1 part by weight (based on the total weight of the composition) of the particular component or compound.

[0016] The term “crosslinker” refers to a molecule capable of forming a covalent linkage between polymers or between two different regions of the same polymer.

[0017] The term “self-crosslinking,” when used in the context of a self-crosslinking polymer, refers to the capacity of a polymer to enter into a crosslinking reaction with itself and / oranother molecule of the polymer, in the absence of an external crosslinker, to form a covalent linkage therebetween. Typically, this crosslinking reaction occurs through reaction of complimentary reactive functional groups present on the self-crosslinking polymer itself or two separate molecules of the self-crosslinking polymer.

[0018] The term “dispersion” in the context of a dispersible polymer refers to the mixture of a dispersible polymer and a carrier. The term “dispersion” is intended to include the term “solution.”

[0019] The term “thermoplastic” refers to a material that melts and changes shape when sufficiently heated and hardens when sufficiently cooled. Such materials are typically capable of undergoing repeated melting and hardening without exhibiting appreciable chemical change. In contrast, a “thermoset” refers to a material that is crosslinked and does not “melt.”

[0020] Unless otherwise indicated, a reference to a “(meth)acrylate” compound (where “meth” is bracketed) is meant to include both acrylate and methacrylate compounds.

[0021] Unless otherwise indicated, “molecular weight” refers to number average molecular weight (Mn). Molecular weight (both number average and weight average (Mw)) are determined by standard methods known to those of skill in the art. Unless otherwise indicated, the method used to determine molecular weight is size exclusion chromatography (SEC), more specifically, gel permeation chromatography (GPC).

[0022] The term “particle size,” as used herein, refers to the mean or average particle size based on particle size distribution (D50), where D50 is the median diameter or the medium value of the particle size distribution, i.e., the value of the particle diameter at 50% in the cumulative distribution. For example, a D50 particle size of 2.0 pm means that 50% of the particles in a given sample are larger than 2.0 pm and 50% are smaller than 2.0 pm. Unless otherwise indicated, the particle size discussed herein is determined by methods known to those of skill in the art, specifically by dynamic light scattering (DLS) analysis.

[0023] The term “conventional coating” as used herein refers to non-coil coating systems or conventional coil coating systems for exterior use made using non-fluorinated resins. Such conventional systems are known to those of skill in the art and may include, without limitation, polyesters, silicon-modified polyesters, and the like.

[0024] The term “on,” when used in the context of a coating applied on a surface or substrate, includes both coatings applied directly or indirectly to the surface or substrate. Thus, for example, a coating applied to a primer layer overlying a substrate constitutes a coating applied on the substrate.

[0025] Unless otherwise indicated, the term “polymer” includes both homopolymers and copolymers (i.e., polymers of two or more different monomers).

[0026] The term “comprises” and variations thereof do not have a limiting meaning where these terms appear in the description and claims.

[0027] The terms “preferred” and “preferably” refer to embodiments of the invention that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful and is not intended to exclude other embodiments from the scope of the invention.

[0028] As used herein, “a,” “an,” “the,” “at least one,” and “one or more” are used interchangeably. Thus, for example, a coating composition that comprises “an” additive can be interpreted to mean that the coating composition includes “one or more” additives.

[0029] Also herein, the recitations of numerical ranges by endpoints include all numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.). Furthermore, disclosure of a range includes disclosure of all subranges included within the broader range (e.g., 1 to 5 discloses 1 to 4, 1.5 to 4.5, 1 to 2, etc.).DETAILED DESCRIPTION

[0030] The present description provides a multilayer coating system. In an aspect, the coating system includes a first layer and a second layer. The first layer is applied over a substrate and includes a first coating composition. The second layer is applied over the first layer and includes a second coating composition. Optionally, the coating system also includes a third layer applied over the second layer.

[0031] In an embodiment, the present description provides a multilayer coating system that includes a first layer applied directly to at least one major surface of a planar metal substrate. In an aspect, this first layer is a primer coating intended to adhere well to the substrate and protect the underlying metal from deleterious effects, such as corrosion, for example. The first layer includes a first coating composition including at least one binder resin component.

[0032] The at least one binder resin component of the first composition is a thermoplastic material or component. Examples of suitable thermoplastic materials include, without limitation, halogenated polyolefins, which include, for example, copolymers and homopolymers of vinyl chloride, vinyl fluoride, vinylidenefluoride, polychloroprene,polychloroisoprene, polychlorobutylene, and combinations thereof. Polyvinyl fluoride (PVF) is a particularly preferred thermoplastic material.

[0033] In the present description, the first coating composition applied to the metal substrate comprises a thermoplastic halogenated polyolefin polymer dispersed in solution. In a preferred aspect, the halogenated polyolefin is polyvinyl fluoride (PVF), a component having the general formula (I) shown below:

[0034] It is believed that PVF has several unique properties that make the polymer particularly amenable to coating applications where chemical resistance , weatherability, and flexibility are desired such as, for example, in coil coating applications, but not currently available with the binder resins or polymers currently used in conventional coil coating applications, including polyesters, polyurethanes, and the like, for example. Without limiting to theory, it is believed that the crystallinity and electrical dipole properties of PVF make the polymer unique and give coatings derived from PVF their superior performance properties.

[0035] Accordingly, in an embodiment, the first layer of the multilayer system described herein includes a first coating composition that includes at least 1 to 30, preferably 2 to 25, more preferably 5 to 20 percent by weight of a polyvinyl fluoride resin component.

[0036] In some embodiments, the first coating composition may include one or more additional resin components. These resin components may be thermoset or thermoplastic. Suitable examples of additional thermoset resin components include, without limitation, homopolymers and co-polymers of polyesters, polyurethanes, epoxy, acrylic, and mixtures or combinations thereof. Suitable examples of additional thermoplastic resin components include, without limitation, polyolefins such as polyethylene, polypropylene, polystyrene, thermoplastic acrylic resins, and the like, and halogenated polyolefins such as copolymers and homopolymers of vinyl chloride, vinylidenefluoride, polychloroprene, polychloroisoprene, polychlorobutylene, and combinations thereof.

[0037] Accordingly, in one aspect, the first coating composition described herein includes an additional resin component, preferably a (meth)acrylic resin component. This additional resin component is preferably present in an amount of up to 10%, more preferably up to 6%, andmost preferably up to 3 to 5% by weight, based on the total weight of the composition. Examples of suitable (meth) acrylic resin components include, without limitation, resins derived from monomers of methyl methacrylate (MMA), ethyl methyl acrylate (EMA), hydroxyethyl methacrylate (HEMA), ethyl acrylate (EA), butyl acrylate (BA), 2- hydroxyethyl acrylate (ELEA), N-(2-hydroxyproply) methacrylamide (HPMA), and mixtures or combinations thereof. In a preferred aspect, the (meth) acrylic resin component is derived from monomers of MMA, EMA, or HEMA.

[0038] Alternatively, in another aspect, the first coating composition described herein includes an additional resin component, preferably a halogenated polyolefin component, more preferably a polyvinylidene fluoride (PVDF) component. This additional resin component is preferably present in an amount of up to 10%, more preferably up to 6%, and even more preferably up to 0 to 5% by weight, based on the total weight of the composition.

[0039] In an embodiment, the present description provides a multilayer coating system that includes a first layer applied directly to at least one major surface of a planar metal substrate and a second layer applied over the first layer. In an aspect, this second layer is a topcoat or top coating intended to be weather resistant, chemical resistant, and capable of maintaining its appearance after prolonged exposure to uv radiation, for example. The second layer includes a second coating composition including at least one binder resin component.

[0040] The at least one binder resin component of the second coating composition is a thermoplastic material or component. Examples of suitable thermoplastic materials include, without limitation, halogenated polyolefins, which include, for example, copolymers and homopolymers of vinyl chloride, vinyl fluoride, vinylidenefluoride, polychloroprene, polychloroisoprene, polychlorobutylene, and combinations thereof. Polyvinyl fluoride (PVF) is a particularly preferred thermoplastic material.

[0041] As explained above, it is believed that PVF has several unique properties that make the polymer particularly amenable to coating applications where chemical resistance, weatherability, and flexibility are desired such as, for example, in coil coating applications, including when the coating is used as a topcoat or as part of a multilayer coil coating system.

[0042] Accordingly, in an embodiment, the second layer of the multilayer system described herein includes a second coating composition that includes at least 40 to 100, preferably 50 to 95, more preferably 60 to 90 percent by weight of a polyvinyl fluoride resin component, based on the total weight of the composition.

[0043] In some embodiments, the second coating composition may include one or more additional resin components. These resin components may be thermoset or thermoplastic.Suitable examples of additional thermoset resin components include, without limitation, homopolymers and co-polymers of polyesters, polyurethanes, epoxy, acrylic, and mixtures or combinations thereof. Suitable examples of additional thermoplastic resin components include, without limitation, polyolefins such as polyethylene, polypropylene, polystyrene, thermoplastic acrylic resins, and the like, and halogenated polyolefins such as copolymers and homopolymers of vinyl chloride, vinylidenefluoride, polychloroprene, polychloroisoprene, polychlorobutylene, and combinations thereof.

[0044] Accordingly, in one aspect, the second coating composition described herein includes an additional resin component, preferably a (meth)acrylic resin component. This additional resin component is preferably present in an amount of up to 10%, more preferably up to 6%, and most preferably up to 3 to 5% by weight, based on the total weight of the composition.

[0045] Alternatively, in another aspect, the second coating composition described herein includes an additional resin component, preferably a halogenated polyolefin component, more preferably a polyvinylidene fluoride (PVDF) component. This additional resin component is preferably present in an amount of up to 10%, more preferably up to 6%, and even more preferably up to 0 to 5% by weight, based on the total weight of the composition.

[0046] Optionally, in some embodiments, the multilayer coating system described herein may include a third layer, a fourth layer, or any number of additional layers applied over the second layer. The composition of these additional layers is not limited, and may include any binder resin components, pigments, and other additives needed to provide the necessary performance or aesthetic appearance required.

[0047] The present description provides methods for making a coating composition. In some embodiments, the method described herein include steps of providing a coating composition including at least about 5 to 20 percent by weight of a polyvinyl fluoride (PVF) resin component. The resin component is then combined with other conventional components used in coating compositions to form a paint with particle size less than 20 pm to optimize coating performance. In an aspect, the process of combining involves standard mixing of various components. Alternatively, combining may involve milling various components together, or in another aspect, the process of combining involves high speed dispersion of the components.

[0048] Conventionally, to make a 2L batch of a paint or coating composition as described herein with particle size of less than 20 pm would take 4 to 5 hours. Surprisingly, and in contravention of expectations in the industry, it only took about 15 to 20 minutes to combine various components and produce a 2L batch of the coating composition with particle size ofless than 20 pm, even without extensive milling required. For a production-sized batch, the time was reduced from the 50 to 70 hours required for a conventional coating to just 1 to 2 hours for the coating described herein. Accordingly, the coating composition described herein may be made or manufactured in significantly less time than currently available coating systems and without a notable increase in cost or production complexity.

[0049] Without limiting to theory, it is believed that the significant reduction in production time is because of the particle size (D50) of the PVF resin component. Commercially available conventional grades of PVF resin generally have particle size (D50) of about 40 pm. However, in the methods described herein, the PVF resin component has particle size (D50) of less than 20 pm, preferably about 15 to 20 pm, and this reduced particle size allows for a significant reduction in production time for both small batches and large productionsized batches of the coating composition described herein. In some embodiments, the PVF resin component may be micronized or otherwise processed by methods known in the art to obtain a particle size of less than 20 pm, preferably 15 to 20 pm.

[0050] The multilayer coating system described herein may be used to produce coated articles. In some embodiments, these coated articles include a substrate, preferably a planar metal substrate, over which the multilayer coating system described herein is applied. Nonlimiting examples of metal substrates that may benefit from having a coating composition of the invention applied on a surface thereof include hot-rolled steel, cold-rolled steel, hot-dip galvanized, electro-galvanized, aluminum, tin plate, various grades of stainless steel, and aluminum-zinc alloy coated sheet steel (e.g., GALVALUME sheet steel).

[0051] The multilayer coating system may be applied to the substrate by any method known to the those of skill in the art, including by a coil coating process, or by spray application. In a preferred aspect, the multilayer coating system is applied by a coil coating process.

[0052] After application to the metal substrate, each layer of the coating system described herein is typically cured or hardened in a heated temperature environment of from about 200 to 500°C, more preferably from about 270 to 470°C. For coil coating operations, the coating is typically baked for about 20 to 60 seconds, to a peak metal temperature (PMT) of from about 200 to 250°C.

[0053] The multilayer coating system described herein has a number of excellent performance characteristics that are equivalent or superior to conventional and currently commercially available coil coating systems made with non-fluorinated resins. These performance characteristics include exceptional chemical resistance (i.e. good cleanability, and optimal resistance to acid and base, as demonstrated by the coating remaining intact aftermore than 450 hours of exposure to 10% HC1 and over 1000 hours of exposure to 10% NaOH), superior formability and elongation (as demonstrated by a 0T rating for T-bend testing), and impact resistance (as demonstrated by a 5B rating on direct and reverse impact testing).

[0054] The multilayer coating system described herein has utility in a multitude of applications. The described may include, for example, a primer, a topcoat, a series of intermediate coats, or any combination thereof. The coating composition may be applied to sheet metal such as is used for lighting fixtures, architectural metal skins (e.g., gutter stock, window blinds, siding and window frames and the like) by spraying, dipping, or brushing, but is particularly suited for a coil coating operation where the composition is applied onto the sheet as it unwinds from a coil and then baked as the sheet travels toward an uptake coil winder. It is further contemplated that the coating composition of the invention may have utility in a variety of other end uses and industries, including, industrial coating applications such as, e.g., appliance coatings; packaging coating applications; interior or exterior steel building products; HVAC applications; chemical industry applications, hospital settings, agricultural metal products; aviation products, garbage and sanitation disposal products, electronic products, medical devices, wood coatings; etc. In a preferred aspect, the cured coating described herein is used as an exterior coating for building materials, architectural skins and the like.EXAMPLES

[0055] The invention is illustrated by the following examples. It is to be understood that the particular examples, materials, amounts, and procedures are to be interpreted broadly in accordance with the scope and spirit of the inventions as set forth herein. Unless otherwise indicated, all parts and percentages are by weight and all molecular weights are weight average molecular weight. Unless otherwise specified, all chemicals used are commercially available from, for example, Sigma-Aldrich, St. Louis, Missouri.TEST METHODS

[0056] Unless indicated otherwise, the following test methods were utilized in the Examples that follow.A. Chemical Resistance

[0057] Chemical resistance tests can be used to determine a cured coating or coating system’s resistance to chemical attack. The test is performed by immersing a test panel with a cured coating applied thereon in acid or alkali solutions at particular concentrations (e.g., 10% HC1, 10% H2SO4, 10% NaOH, etc.) for a given period of time, as indicated in ASTM D1308 (Standard Test Method for Effect of Household Chemicals on Clear and Pigmented Coating Systems). Results are reported as the hours taken to blister formation. The results of this test for coatings prepared according to the present description are presented in Table 1.B. Corrosion Test

[0058] The corrosion resistance of cured coatings prepared from the composition described herein is tested using the salt fog method, as described in ASTM Bl 17 (Standard Practice for Operating Salt Fog Apparatus). Results are expressed on a scale of 0 tolO, where “0” indicates the coating is completely corroded, observed by bubbling or blistering of the film in all areas, and “10” indicates the coating is unchanged from before it was subjected to the corrosive environment.

[0059] The corrosion resistance of cured coatings prepared from the composition described herein is also tested by measuring creep after exposure to a corrosive environment, as described in ASTM D1654-08 (Standard Test Method for Evaluation of Painted or Coated Specimens Subjected to Corrosive Environments). A coating is applied to a panel and cured. The panel is then scribed to metal and exposed to salt fog for a given period of time. Paint loss from the scribe is measured, and results are expressed as the amount of creep (in mm) from the scribe.

[0060] Blister ratings of 10 and creep from scribe of less than about 3 mm are expected for commercially viable coating systems. The results of this test for coatings prepared according to the present invention are presented in Table 1.C. Flexibility Testing

[0061] The coating flexibility test measures the strength of adhesion between the coating and substrate in coil-coated sheets of metal to demonstrate that the coating will not peel or crack during the fabrication process. The test is as described in ASTM D4145 (Standard Test Method for Coating Flexibility of Pre-painted Sheet). The test can be performed in two ways:non-tape off (NTO) or non-fracture (NFX). For both tests, coated sheets of the metal substrate are folded over upon themselves to form a shape called T-bend where the coated side is on the exterior of the T-bend. In the non-tape off method, ASTM D3359 tape is placed on the bent portion and quickly removed. The tape is observed to assess if any of the coating has come off. In the non-fracture method, the test sheet is monitored or observed visually for obvious crack formation after each bend. For both methods, the first bend (where there is no panel thickness between the two exterior surfaces of the T-bend) is called “OT” and therefore, a rating of OT means that no coating has come off on the tape and / or no cracks or slips in the coating were visually observed at the first bend.

[0062] The results of this test for coatings prepared according to the present invention are presented in Table 1.D. Pencil Hardness

[0063] The hardness of cured coatings prepared from the powder compositions is tested using by the pencil method, as described in ASTM D3363 (Standard Test Method for Film Hardness by Pencil Test). Results are reported in terms of the last successful pencil prior to film rupture. Thus, for example, if a coating does not rupture when tested with an F pencil, but ruptures when tested with a H pencil, the coating is reported to have a pencil hardness of F. For the coating systems described herein, results of pencil hardness testing are as shown in Table 1.E. Reverse Impact Resistance

[0064] The reverse impact resistance of cured coatings is tested using the methods described in ASTM D2794 (Standard Test Method for Resistance of Organic Coatings to the Effects of Rapid Deformation), as modified by the crosshatch adhesion test described in ASTM D3359 (Standard Test Methods for Rating Adhesion by Tape Test). Briefly, the coatings to be tested are applied to metal panels and cured. A standard weight is dropped a specific distance to strike an indenter that deforms the cured coating and the substrate to which it is applied.Adhesion of the coating in the deformed area is determined using the tape test. A rating of 5B indicates that no coating is removed in the deformed or impact area. For the coating systems described herein, results are as shown in Table 1.Example 1. Preparation of PVF Coating System

[0065] A 100 g sample of PVF primer was prepared by combining 21 g of polyester resin, 2.6 g acrylic resin, 0.1 g of PVDF resin, 5.5 g of PVF resin, 6.3 g of mix alcohol, 8.4 g of mix ether acetate, 4.6 g of propylene carbonate, 4.6 g of mix benzene, 14 gram of aromatic naphtha, 7.8 g of kaolin clay, 5.3 g of titanium dioxide, 8.3 g of strontium chromate, and other additives commonly used in coil coating compositions.1

[0066] A 100 g sample of PVF topcoat (white) (Example 1 A) was prepared from 30 g of PVF, 3.0 g of acrylic resin (Composition 1 as shown below in Table 1), 2.0 g of PVDF, 0.9 g of crosslinker, 0.7 gram of plasticizer, 0.3 g of wax, 0.2 g of antioxidant, 38.2 g of propylene carbonate, 5.8 g of mix ether acetate, 3.1 g of glycol ether, 0.6 g of toluene, 0.2 g of cyclohexanone, 13 g of titanium dioxide, and other additives commonly used in coil coating compositions.

[0067] A 100 g sample of PVF topcoat (white) (Example IB) was prepared from 23.3 g of PVF, 8.6 g of acrylic resin (Composition 1 as shown below in Table 1), 2.2 g of PVDF, 2.1 g of crosslinker, 2.4 gram of plasticizer, 0.3 g of wax, 0.2 g of antioxidant, 32.1 g of propylene carbonate, 11.8 g of mix ether acetate, 3.1 g of glycol ether, 0.6 g of toluene, 0.2 g of cyclohexanone, 13 g of titanium dioxide, and other additives commonly used in coil coating compositions.

[0068] For comparison, Example 2 represents a PVF topcoat composition prepared using a commercially available acrylic resin in the same proportion as Example 1 A (Composition 2 as shown below in Table 1).

[0069] Metal tests panels are coated for performance testing. The test panels may be steel, aluminum or Galvalume, and they may be un-pretreated or have chromate and non-chromate pretreatment applied. Each test panel was coated with PVF primer as prepared above at dry film thickness (DFT) of 0.2 to 0.3 mil and cured at peak metal temperature (PMT) between 390°F to 420°F. A layer of PVF topcoat was then applied over the primer layer at DFT of 0.8 to 0.9 mil and cured at PMT of 450 to 490°F. After curing and drying, each test panel is subjected to a series of performance tests to determine if the coating meets commercial or industry standards. For comparison of chemical resistance, panels coated with standard1The terms "mix alcohol / ' "mix ether acetate / ' and "mix benzene" refer to a mixture of various alcohols or glycol solvents, a mixture of various glycol ether acetates, and a mixture of various benzene-based solvents respectively. These mixtures are well known to those of skill in the art.commercially available polyester (PE) or silicon-modified polyester (SMP) coil coating systems with either white or dark colors are also tested in the same way. Results are as shown in Table 2.Table 1. PVF Composition with Acrylic Co-ResinTable 2. Performance Characteristics

[0070] The complete disclosure of all patents, patent applications, and publications, and electronically available material cited herein are incorporated by reference. The foregoing detailed description and examples have been given for clarity of understanding only. No unnecessary limitations are to be understood therefrom. The invention is not limited to the exact details shown and described, for variations obvious to one skilled in the art will be included within the invention defined by the claims. The invention illustratively disclosed herein suitably may be practiced, in some embodiments, in the absence of any element which is not specifically disclosed herein.

Claims

WHAT IS CLAIMED IS:

1. A multilayer coating system, comprising: a first layer applied over a substrate, said first layer comprising a first coating composition including at least about 5 to 20 percent by weight of a polyvinyl fluoride (PVF) resin component; a second layer applied over the first layer, said second layer comprising a second coating composition including at least 40 to 100 percent by weight of a polyvinyl fluoride (PVF) resin component; and optionally, at least a third layer applied over the second layer.

2. The system of claim 1, wherein the first coating composition comprises an additional resin component.

3. The system of any of the above claims, wherein the first coating composition comprises about up to about 5 percent by weight of an additional resin component.

4. The system of any of the above claims, wherein the additional resin component of the first composition is a fluorinated resin.

5. The system of any of the above claims, wherein the additional resin component of the first composition comprises polyvinylidene fluoride (PVDF).

6. The system of any of the above claims, wherein the additional resin component of the first composition comprises at least one resin derived from (meth)acrylic or (meth)acrylate monomers.

7. The system of any of the above claims, wherein the second coating composition comprises up to about 5 percent by weight of an additional resin component.

8. The system of any of any of the above claims, wherein the additional resin component of the second coating composition is a fluorinated resin.

9. The system of any of the above claims, wherein the additional resin component of the second coating composition comprises polyvinylidene fluoride (PVDF).

10. The system of any of the above claims, wherein the additional resin component comprises at least one resin derived from (meth)acrylic or (meth)acrylate monomers.

11. The system of any of the above claims, wherein the PVF resin component has particle size of about 15 to 20 pm.

12. The system of any of the above claims, wherein the system demonstrates optimal chemical resistance, flexibility, impact resistance, and weatherability.

13. A method, comprising providing a coating composition including at least about 5 to 20 percent by weight of a polyvinyl fluoride (PVF) resin component; and combining the resin component with other components to form a paint with particle size less than 20 pm, wherein the process of combining the resin component with other components takes 15 to 20 min for a 2L batch.

14. The method of claim 10, wherein the PVF resin component has particle size (D50) of about 15 to 20 pm.

15. The method of claim 10, wherein the PVF resin component is micronized to obtain a particle size (D50) of about 15 to 20 pm.

16. The method of claim 10, wherein the step of combining the resin component with other components comprises milling.

17. The method of claim 10, wherein the step of combining the resin component with other components comprises high-speed dispersion.

18. A coated article, comprising a planar metal substrate; and a coating system applied thereon, the system comprisinga first layer applied over a substrate, said first layer comprising a first coating composition including at least about 5 to 20 percent by weight of a polyvinyl fluoride (PVF) resin component; a second layer applied over the first layer, said second layer comprising a second coating composition including at least 40 to 100 percent by weight of a polyvinyl fluoride (PVF) resin component; and optionally, at least a third layer applied over the second layer.

19. The article of claim 12, wherein the coating is applied by a coil coating process.

20. The article of claim 12, wherein the coating system is applied by spray application.

21. The article of claim 12, wherein the coating system is an extrusion coating system.

22. The system of claim 1, wherein the coating system is a coil coating system.

23. The system of claim 1, wherein the coating system is a spray-applied coating system.

24. The system of claim 1, wherein the coating system is spray-applied to an extruded metal substrate.

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