MXPA99003750A - Vinylidenedifluoride-based coating compositions - Google Patents

Abstract

A coating composition based on a dispersed fluoropolymer resin is provided. The composition includes a vinylidene difluoride-based polymer such as PVDF, an organic solvent and a dispersant. A method of forming a protective coating on a metal substrate with the fluoropolymer resin-based coating composition and a composite material having at least one surface coated with a vinylidene difluoride-based polymer film are also provided.

Description

RECOVERY CHECKS BASED? N DIFÜD OLRO DE IM? LTIIDENO BACKGROUND OF THE LTNVLENCIÓ1T Pigmented fluoropolymer coatings have been widely used today to coat architectural panels. These coatings can provide an attractive finish which will resist discoloration and powder disintegration for extended periods of time. In the production of coating compositions for components of structural construction, such as metal building panels, there are often competing requirements which must be balanced. Good durability properties such as color retention, resistance to usual wear and resistance to powder disintegration on the face in severe weather conditions as well as corrosive industrial pollutants are required. Good flexibility is also needed in order to facilitate metal fabrication without loss of coating addition. In the coil coating area, difficulties are exemplified with conventionally used plastisol-based coating compositions. PVC plastisols are desirable coating vehicles from REF .: 29827 the manufacturing point of view, thick film capacity and ability to be formulated with a high concentration of solids, but generally show little durability, color retention, resistance to powder disintegration and resistance to dirt. As a result, compromises often have to be made either in terms of the final properties of the film or the working capacity of the coated substrate. Accordingly, there is a continuing need for improved coatings which provide excellent durability and which at the same time allow the manufacture of the coated substrate with a thick film capacity and a high solids content.

BRIEF DESCRIPTION OF THE INVENTION The present invention provides a fluoropolymer resin-based coating composition capable of forming a tough coating, resistant to degradation - weathering and other forms of chemical attack. The present composition contains fluoropolymer fillers and / or substantially larger total solids compared to conventional PVDF coating compositions and therefore minimizes the environmental problems associated with the use of volatile organic solvents. The coating composition can be applied by a variety of conventional methods and, after heating, provides a resilient, corrosion resistant and cured film. The coating composition includes the fluoropolymer resin dispersed in an organic solvent in the presence of a dispersant. The fluoropolymer resin typically includes a polymer based on vinylidene difluoride and, preferably, a polyvinylidene difluoride ("PVDF"). As used herein, the term "PVDF" refers to homopolymers of vinylidene difluoride. The composition also generally includes a pigment and polymeric additives designed to improve the hardness and / or adhesion of the resulting cured film, for example, a thermoplastic acrylic polymer or a combination of a hydroxy functional polymer and a curing agent such as an aminoplast resin. . Based on the desired properties of the final cured film, the composition may include other additives such as an agent that produces matte appearance to reduce gloss or an additive that improves the wear resistance customary. The present invention also provides a method of coating a metal substrate to provide a cured polymer film based on vinylidene difluoride on at least one surface of the substrate. The method includes applying the coating composition on a surface of the metal substrate to form a film, for example, by roller coating or spraying the coating composition on the surface of the substrate. The coated metal substrate is then heated so that the coating layer cures to form a tough cured film which adheres to the surface of the substrate. The coated metal substrate is cured by heating the vinylidene difluoride-based resin film to a temperature sufficient to coalesce the fluoropolymer resin. The present invention also provides a composite material which includes a metal substrate having at least one surface covered with a cured polymer film based on vinylidene difluoride. A first coating is typically applied directly to the surface of the metal substrate and then one or more coatings of the present coating composition are applied onto the sizing. Alternatively, the present composition can be used to form a protective clear coat on top of an underlying pigmented fluorocarbon polymer based layer. The pigmented layer can be formed using a pigmented version of the present composition or a conventional pigmented fluorocarbon polymer based composition. In any case, the pigmented layer is typically applied over a size coat. The cured film results from coating a substrate surface with the coating compositions described above and heating the coated metal substrate.

DESCRIPTION DET-AT.T.ANA OF THE INVENTION The present coating composition is useful for protecting a wide variety of metal substrates, such as building components or buildings formed of aluminum, hot dipped galvanized steel and zinc-aluminum alloys on steel. The coating composition typically includes at least about 30% by weight, preferably at least about 50% by weight, and most preferably about 55 to about 80% by weight of total solids. For some applications, for example where in coating it is to be applied in the form of a paste, the coating composition can include a very high proportion of total solids, (eg, up to about 90% by weight) and resin fluoropolymer (up to about 75% by weight based on the total weight of the composition of a polymer based on vinylidene difluoride). When the composition is intended to be used to form a transparent coating, the polymer resins constitute substantially all of the solids content of the coating and the total solids loading is typically at least about 30% by weight and preferably from about 30% by weight. up to about 40% by weight. In the composition it generally has the correct viscosity and solids content to allow application to the metal substrate via the desired method (e.g., spraying, winding, dipping, brushing or slotting) without further dilution. For some applications (for example when the composition is used to form a clear coat), it may be desirable to adjust the viscosity of the coating composition for a particular method and application equipment. The above proportions are based on weight, based on the total weight, and all ratios and ratios herein, including those in the claims, are by weight, unless stated otherwise. The coating composition includes a fluoropolymer dispersion, that is, a dispersion of the fluoropolymer resin particles in an organic solvent, such as a non-aromatic ketone or ester. If the resin particle size is too large, stability problems with the dispersion can be experienced. Typically, the average particle size is from about 1 to about 15 microns, and preferably from about 2 to about 8 microns. Generally the present composition includes at least about 30% by weight, preferably at least about 35% by weight and more preferably about 40-50% by weight of a polymer based on vinylidene fluoride (based on the total weight of the coating composition). The vinylidene difluoride-based polymer typically constitutes at least about 70% by weight and preferably at least about 85% by weight of the resin solids present in the composition. In some cases, the vinylidene difluoride-based polymer can constitute as much as about 95% to 100% by weight of the resin solids. Transparent versions of the composition pressure include about 35-45% by weight resin solids which include at least about 85% by weight of PVDF and at least about 5% by weight of a thermoplastic acrylic polymer. More preferably, transparent coating compositions include from about 37 to about 95% by weight of PVDF and from about 5 to about 13% by weight of thermoplastic acrylic polymer, for example, a copolymer of one or more esters of alkyl methylacrylate. lower (alkyl of and / or one or more of lower alkyl acrylate esters.

Any of a variety of standard application methods can be used to apply the coating compositions, for example, coating with brush, bar, groove, roller or spray. The desired viscosity will vary based on the particular end use, the desired dry film thickness and the coating application method. For example, when the coating composition is to be applied through a coil coating process (eg, by reverse roller coating), the composition preferably includes at least about 50% by weight, and more preferably from about 55 to about 80% by weight total solids and typically has a viscosity from about 40 to about 120 seconds and preferably from about 60 to about 120 seconds (Ford cup # 4 @ 25 ° C (77 ° F)). The coating compositions to be applied by means of a coil coating process most preferably have a viscosity from about 80 to about 105 seconds (Ford cup # 4 @ 25 ° C (77 ° F)) and include about 35% by weight to about 50% by weight of the polymer based on vinylidene difluoride (based on the total weight of the composition). Roll coating such a composition allows the formation of films having a wet film thickness of 5-10 mils (127-254 microns) and a cured dry film thickness of 51-152 microns (2). -6 thousandths of an inch). When the present composition is used as a transparent topcoat, the composition is typically applied at a wet film thickness of 25 to 76 micrometers (1-3 mils) and produces a cured dry film thickness of about 5 to 25 micrometers. (0.2-1.0 thousandths of an inch). When the spray application is to be used, the pigmented versions of the present composition preferably include at least about 50% by weight total solids and typically have a viscosity from about 25 to about 60 seconds (# 2 Zahn). When the present composition is to be used to form a transparent coating, total solids contents of 35 to 45% by weight and PVDF contents of at least about 30% by weight are common. Such composition coatings can be used to prepare spray coatings (e.g. electrostatic spraying) having wet film thicknesses from about 51 to about 102 microns. (2-4 mils) and a dry film thickness from about 25 to about 51 microns (1.0-2.0 thousandths of an inch). When the composition is to be used as a clear topcoat, spray applications are common to produce coatings having a wet film thickness of about 25 to 51 micrometers (1-2 mils) and a dry film thickness of approximately 8 to 18 micrometers (0.3-0.7 thousandths of an inch). In some cases, the present composition can be diluted prior to its application by spraying with a suitable reducing solvent, for example, xylene, butylcarbitol or a combination thereof. The particular reducing solvent used depends on numerous factors including pipe conditions and the desired or specified dry film thickness ("DFT"). Several different film-forming fluoropolymers are useful in the present invention, such as polyvinylidene difluoride and various copolymers of vinylidene difluoride. The film-forming fluoropolymer resin typically includes PVDF having an MH of from about 150,000 to about 500,000. More preferably, the polyvinylidene difluoride has an Mw from about 350,000 to about 450,000, a Mw / Mn ratio of from about 3.5 to about 5.0 and / or a melting point of about 150-170 ° C. An example of a commercially available polyvinylidene difluoride which is particularly suitable for use in the present composition is Kynar "" 500 (available from Elf Atochem, Philadelphia, PA).

Copolymers of vinylidene difluoride including at least about 75 percent by weight, preferably 90 percent by weight or more of monomer units of vinylidene difluoride can also be used. Examples of monomers which can be copolymerized with vinylidene difluoride include ethylene, propylene, isobutylene, styrene, vinyl chloride, vinylidene chloride, difluorochloroethylene, chlorotrifluoroethylene, tetrafluoroethylene, trifluoropropylene, hexafluoropropylene, vinyl formate, vinyl acetate, propionate. vinyl, vinyl butyrate, methyl methacrylate, ethyl acrylate, acrylonitrile, methacrylonitrile, N-butoxymethylacrylamide, alkyl acetate and isopropenyl acetate. A group of vinylidene difluoride copolymers which are particularly suitable for use in the present compositions are copolymers formed of at least about 90% by weight of monomer units of vinylidene difluoride and one or more hydrophobic fluorinated monomers such as dif 1 uoroc 1 oroeti 1 e, chlorotrifluoroethylene, tetrafluoroethylene, trifluoropropylene, and hexafluoropropylene. Copolymers of this type are referred to herein as "fluorinated hydrophobic VDF copolymers". Typically, all monomers used to form the fluorinated hydrophobic VDF copolymer include at least one fluorine atom covalently bonded to a carbon atom of a carbon-carbon double bond. A wide variety of organic solvents can be used to formulate the present fluoropolymer dispersions. The organic solvent typically acts as a latent solvent for fluoropolymer; that is, the fluoropolymer is substantially insoluble and is dispersed in the solvent at room temperature, but is solvated or dissolved in the solvent when the composition is heated. The solvent generally constitutes from about 1.0 to about 50% by weight and, preferably, about 25 to about 40% by weight of the composition. When the composition includes substantial amounts of a ketone solvent, such as isophorone, a smaller amount of a non-aromatic ester can also be used, for example from about 5 to about 20% by weight. In an embodiment of the invention, the solvent component of the composition preferably includes a higher amount of a non-aromatic ester. In some cases, it may be preferable to choose a solvent that does not totally volatilize under the heating conditions used to form the dried film on a substrate. In such cases, the remaining residual solvent in the film based on dry fluoropolymer can act as a plasticizer. For other applications, it may be preferable to choose a solvent that will volatilize essentially completely under the heating conditions used. Preferably, the solvent has a boiling point from about 170 ° C to about 400 ° C and more preferably from about 200 ° C to about 350 ° C. In a preferred embodiment of the invention which can be used for coil coating applications, the composition has a solvent component which includes at least 50% by weight (based on total solvent) of solvent having a point of boiling between about 250 ° C and about 300 ° C. Preferably, such compositions include about 60-80% by weight of total solids and from about 35 to about 50% by weight of the polymer based on vinylidene difluoride. Coating compositions with high concentrations of solids of this type, which include at least about 70% by weight and, preferably at least about 85% by weight (based on total resin) of polymer based on vinylidene difluoride, such as PVDF, can be used to form coil coatings having a substantially higher thickness compared to that which can be obtained with conventional PVDF coatings without the formation of blisters. For example, the pigmented embodiments of the present invention include a substantial fraction (on a total solvent base) of solvent having a boiling point between about 250 ° C and about 300 ° C which allows the formation of coil coatings with a dry film thickness ("DFT") of more than two times the DFT that can be obtained using conventional coating compositions with 70% PVDF. Conventional solvents which can be used in the present invention include glycerol esters, glycol esters, esters (for example butyrates) of other aliphatic polyols, phthalates, adipates, benzoates, azelates, carbonates, trimellitates, phosphates, citrates, stearates, sebacates, glutarates, oleates, alkyd substances, polymeric esters, epoxidized oils, epoxitalates, amide-esters, sulfonamides, terpenes, aromatic substances and ketones. Preferably, the solvent includes a non-aromatic solvent having from about 10 to about 30 carbon atoms; more preferably from about 12 to about 25 carbon atoms. Examples of suitable non-aromatic solvents include esters of aliphatic dibasic acids and di- or tri-esters of aliphatic polyols and alkylene ether ethers monoesters. Preferably, the solvent includes a diester of a branched aliphatic diol, and most preferably a butyrate diester of a branched octane diol, such as 2,2,4-trimethyl-1,3-pentanediol diisobutyrate ("TXIB"). Other preferred solvents for use in the present invention include polyoldiesters such as triethylene glycol bis (2-ethylhexanoate) ("TEG-EH"), and esterified ethers, for example esters of glycol monoethers such as methyl ether propylene glycol acetate ("PMA" or "PM acetate") or dipropylene glycol methyl ester ("DPMA" or "DPM acetate"). Other examples of suitable solvents which may be present to some extent as part of the solvent portion of the present compositions include phthalates such as butylbenzyl phthalate and dialkyl phthalates (eg, di (2-ethylhexyl) phthalate, dimethyl phthalate. and dioctyl phthalate); aromatic substances such as toluene and xylenes; ketones such as isophorone; esters of aliphatic dibasic acid such as dioctyl azelate, diisodecyl adipate and di (2-ethylhexyl) sebacate; phosphates such as trioctyl phosphate, and 2-ethylhexyl diphenylphosphate; epoxy plasticizers such as epoxidized soy bean oil, epoxidized bait oil fatty acid 2-ethylhexyl esters and other conventional polyester solvents commonly used as plasticizers. Preferably, a major amount (ie, at least about 60% by weight) of the solvent portion of the pigmented portions of the present composition consist of one or more non-aromatic esters. The solvent fraction may include a minor amount (ie, no more than about 30% by weight) of a non-aromatic ketone and / or a hydroxy functional solvent such as glycol monoether (for example butylcarbitol) or a half ester or an aliphatic diol ( for example 2, 2, 4-trimethyl-1,3-pentanediol monoisobutyrate). More preferably, at least about 90% by weight, and more preferably, substantially all of the solvent portion consists of one or more non-aromatic esters. One embodiment of such preferred compositions are dispersions in which at least about 95% by weight of the solvent portion is 2, 2, 4-trimethyl-1,3-pentanediol isobutyrate ("TXIB"). Other preferred compositions include a solvent component consisting essentially of TXIB, butylcarbitol acetate, PM acetate, DPM acetate or mixtures thereof. The embodiments of the present invention designed for use as clear coatings typically include alkyl substituted benzene, a phthalate, a glycol monoether, a glycol ester and / or a monoester of an alkyleneoxyether. Examples of suitable organic solvents which can be used to formulate transparent versions of the present compositions include toluene, xylene, dimethyl phthalate, propylene glycol methyl ether acetate, dipropylene glycol methyl ester acetate, butyl cellosolve, n-butanol and mixtures thereof. The present fluoropolymer resin-based compositions also include a dispersant. Although it is not desired to limit the invention, it is considered that the dispersant functions to maintain the separation between the fluoropolymer particles and thus acts as a dispersing aid. It has been found that the dispersants commonly used in the formulation of pigment dispersions are suitable for use in the present compositions. The dispersant typically contains functionality capable of being absorbed onto the surface of a fluoropolymer pigment or particle. The compounds include polar groups (for example amino groups) on one end, and a portion of which is soluble in the continuous phase of the solvent (a hydrophobic glue) at the other end, which are suitable for use as the dispersant. A particularly suitable class of dispersants for use in the present compositions are referred to herein as "hyperdispersants". As used herein, the term "hyperdispersant" refers to dispersants or dispersants which, when included in up to about 3% by weight in a solvent-based formulation, allow the preparation of stable dispersions containing at least about 90% by weight of PVDF (on a base of resin solids) at PVDF fillers of about 35% by weight or more. Examples of suitable hyperdispersants include fluorinated anionic dispersants and polymeric dispersants having one or more amino groups covalently attached to the polymer. Hyperdispersants are typically used at relatively low concentrations (eg, 0.01-0.5% by weight) in formulations containing from about 25% to about 35% by weight of PVDF. When the formulation includes more than about 40% by weight of PVDF, 0.1 to about 3.0% by weight of hyperdispersant is generally used. The dispersant may contain one or more amino groups covalently attached to a polymer backbone or to pendant side chains of a polymer. Examples of suitable polymeric dispersants include oxyalkylated amines and polymeric polyester / polyamide condensates. Suitable oxyalkylated amines include oxyalkylated aminoalcohols such as Solsperse ™ 2000 (available from Zeneca, Inc.) and oxyalkylated alkylamines such as Tetronic ™ 150R1 (available from BASF). Tetronic ™ 150R1 ("T150R1") is a polymer formed by the reaction of 1,2-ethanediamine with propylene oxide and ethylene oxide. Polymers of the latter type are generally referred to herein as a "polymeric oxyalkylated ethanediamine". An example of a suitable polymeric polyester / polyamine condensate is commercially available under the tradename Solsperse "" 28000 from Zeneca, Inc., Wilmington, DE. Alternatively, the amine groups can be linked to the polymer as an amine salt of a carboxylic acid group. Examples of such amine salt containing dispersants include alkylammonium salts of acidic polyesters (e.g. Disperby ^ -dO, available from BYK-Chemie, USA, Wallingford, CT); unsaturated polyamine salts and higher molecular weight acid esters such as Antiterra "U80 (BYK Chemie, USA) Another type of dispersant which can be used in the present composition are partial amides of higher molecular weight unsaturated polycarboxylic acids, such as Disperplast "I (available from BYK-Chemie, USA). Fluorinated anionic dispersants are another class of hyperdispersants which are particularly effective for use in the present compositions. Examples of suitable fluorinated anionic dispersants include salts of fluorinated alkyl phosphate partial esters, fluorinated alkylsulfonic acid salts and fluorinated carboxylic acid salts. Typically, the present compositions include from about 0.005 to about 5.0% by weight and, preferably, from about 0.01 to about 3.0% by weight of the dispersant. When the composition includes a relatively high load of solids (for example of at least about 55% by weight) and PVDF (for example of at least about 35% by weight), typically from about 0.5 to about 3.0% by weight is used. Dispersant weight. When the composition is a clear coating having a total solids content of about 35-45% by weight and a PVDF content of about 30-40% by weight, generally lower concentrations of the dispersant are used (eg 0.01-0.2% in weigh) . When designing a particular formulation, the dispersant and the solvent system are typically chosen to complement each other. Amine-based polymer dispersants such as Solsperse * 28000 and Tetronic ™ 150R1 are particularly effective in formulations wherein the predominant solvent component is an ester or mixture of esters. Specific examples of such formulations include dispersions of PVDF in TXIB, butylcarbitol acetate and / or propylene glycol monomethyl ether acetate which include Solsperse ™ 2000, Solsperse ™ 28000 or Tetronic ™ 150R1. When the coating composition is based on a ketone solvent, such as isophorone, the fluorinated anionic surfactants can be particularly effective as hyperdispersants (for example, such as Zonyl FSP (available from Dupont). Suitable examples include salts of polyfluorosulfonic acid ( for example Forafac ™ 1176 available from Elf Atochem)). Suitable fluorinated alkylsulfonic acid salt hyperdispersants typically include sulfonic acid acids having a formula: < -nF (2n + l) '' C2H4"S0" M * where n is an integer from 4 to 10, and M * is KX Na + or NH4X Specific examples of suitable fluorinated alkylsulfonic acid salt dispersants include C6F13-C2H4 -S03 ~ K * and fluorinated alkylcarboxylic acid salts are another class of fluorinated anionic surfactants suitable for use in the present coating compositions. Examples of suitable fluorinated alkylcarboxylic acid salts include carboxylic acid salts having the formula: CnF (2n + 1) -C02-M * where n is an integer from about 4 to 10, and M * is KX Na * or NH4 *. A specific example of a suitable fluorinated alkylcarboxylic acid salt is C6F13-C02-NH4X Fluorad "11 FC-129 is an example of a commercially available fluorinated alkylcarboxylic acid salt (available from 3M) which can be used in the present compositions. In order to improve the hardness and adhesion of the resulting cured film, the present compositions may include a hydroxy functional polymer, for example, a hydroxyacrylic polymer, Those coating compositions which contain the hydroxy functional polymer typically include a curing agent, such as an aminoplast resin, too The hydroxy functional polymer is subjected to wide variation and is typically a solvent-soluble copolymer of monoethylenic monomers containing from about 1% by weight to about 25% by weight of hydroxy functional monomer. it is usually the only reactive group in the cop olimer, although a small amount of carboxylic acid functionality is permissible, although it is not essential. Preferably, the hydroxy monomer content is from 2 to 10% by weight of the monomer mixture. Various hydroxy-functional monomers can be used, but it is preferred to use a hydroxyalkyl ester of a monocarboxylic acid, such as acrylic acid or methacrylic acid. The alkyl groups contemplated are mainly those containing 1-4 carbon atoms and illustrated by methyl, ethyl, propyl or butyl, however, esters of alcohols having up to 12 carbons can also be used. Preferred hydroxy-functional monomers include 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate. Also useful are hydroxyalkyl ethers such as alkyl alcohol hydroxyethyl ether. The hydroxy-functional copolymer can be produced by free-radical polymerization of a mixture of monoethylenically unsaturated monomers including the necessary ratio of a hydroxyalkyl acrylate or methacrylate. The other monomers are preferably acrylic and methacrylic esters of alcohols containing from 1 to 6 carbon atoms and preferably 1 or 2 carbon atoms. More preferably, the non-hydroxy monomers include at least about 50% methyl methacrylate, n-butyl methacrylate and / or ethyl acrylate. Small amounts, for example about 1-2% by weight of a carboxylic acid, such as acrylic acid or methacrylic acid, can also be included in the monomer mixture. The hydroxy copolymer is preferably used in an amount of from about 1 to about 15% by weight, and more preferably from about 2 to about 10% by weight of the composition. An aminoplast resin is typically added to the composition in an amount sufficient to cure the hydroxy-functional polymer. The weight ratio of the hydroxy-functional polymer to the aminoplast resin is typically from about 2: 1 to about 10: 1, and preferably from about 3: 1 to about 6: 1. Aminoplast resins are based on the addition products of an aldehyde (preferably formaldehyde) with a substance having amino or amido groups. Examples of suitable aminoplast resins include condensation products obtained from the reaction of alcohols and formaldehyde with melamine, urea or benzoguanamine. These condensation products can be monomeric or polymeric. Condensation products of other amines and amides may also be used, for example, condensates of triazine aldehydes, diazines, triazoles, guanadines, guanamines and melamines substituted with alkyl and aryl. Some examples of such compounds are, N, N'-dimethylurea, benzourea, dicyandimide, formaguanamine, acetoguanamine, glycoluril, amelin-2-chloro-4,6-diamino-1,3,5-triazine, 6-methyl-2, 4-diamino-1,3,5-triazine, 3,5-diaminotriazole, triaminopyrimidine, 2-mercapto-4,6-diaminopyrimidine, 3,4,6-tris (ethylamino) -1,3,5-triazine and the like . Although the most commonly used aldehyde is formaldehyde, other similar condensation products can be made from other aldehydes such as acetaldehyde, crotonaldehyde, acrolein, benzaldehyde, furfural, glyoxal and the like. The preferred aminoplast curing agent is simply a condensate of formaldehyde with an amine, preferably melamine, to provide a resin with methylol functionality that hardens by heat. Although many aminoplast resins are widely useful, such as the urea and formaldehyde condensates and the benzoguanamine and formaldehyde condensates, it is preferred that the aminoplast resin be a polyalkoxymethylmelamine resin in which the alkyl group consists of 1-4 carbon atoms. Suitable melamine-formaldehyde condensates are readily available commercially and are usually etherified with lower alcohols for use in organic solvent solution, as is well known. Examples of suitable aminoplast curing agents include an etherified melamine formaldehyde condensate as solutions in organic solvent (for example polymethoxymethylmelamine such as Cymel 303, available from Cytec). The aminoplast resin is typically present from 0.1 to 10% by weight of the total resin solids, and preferably in an amount from 0.2 to 3.0% by weight of the total resin solids. Although aminoplast resins are preferred for curing the hydroxy-functional copolymer, it is also possible to use any curing agent that reacts with the hydroxy functionality, such as blocked phenoplastic resins or polyisocyanates. Suitable blocked isocyanate curing agents include isophorone diisocyanate blocked with methyl ethyl ketoxime or 2,4-toluene diisocyanate blocked with octyl alcohol. The class of blocked isocyanate curing agents is well known and these agents are well known for carrying out curing by formation of urethane groups with the hydroxy functionality on the coating composition when the support causes the blocked isocyanate groups to dissociate and become active When the present compositions are used to form a clear coat, the formulation typically includes a thermoplastic resin, such as a thermoplastic acrylic polymer. Thermoplastic acrylic resins are typically the polymerized ester derivatives of acrylic acid and methacrylic acid. The esters are formed by the reaction of acrylic or methacrylic acid with suitable alcohols, for example, methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol and 2-ethylhexyl alcohol. Generally speaking, the larger the alcohol portion of the ester, the softer and more flexible the resin will be. Methacrylic esters tend to form harder films than the corresponding acrylic ester. Monomers such as styrene, vinyltoluene, vinyl chloride and vinylidene chloride can also be reacted with the acrylic and methacrylic esters so that thermoplastic resins with excellent properties are produced. A particularly suitable resin is a copolymer of methyl methacrylate and ethyl acrylate having a molecular weight (Mw) of between about 50, 000 and approximately 150,000. The present compositions may be transparent (substantially colorless) when they are designed to be applied as a protective topcoat. However, more commonly, the coating compositions include a pigment. The pigment loading will depend on several factors including the desired opacity, color and chemical resistance. Typical pigmented versions of the present composition include from about 5 to about 25, and preferably from about 10 to about 20,% by weight of one or more pigments. Also conventional additives which include surfactants, antioxidants, ultraviolet absorbing substances and stabilizers, rheology control agents, coalescing agents and the like can be added to the present coating composition. For example, in order to avoid yellowing and / or deterioration during baking, the present coating compositions may include an antioxidant such as Irgonox 1010 (available from Ciba-Geigy). An agent that produces a matte appearance, such as the product Degussa 0K-412 or a silica (for example Syloid 7000 available from W.R. Grace) can be added to reduce the brightness reading to 60 ° in the desired range. An additive such as wax (for example Polymekon or Paxwax wax) or micronized PTFE can be added in order to improve the lubricity of the surface and thus improve the current wear resistance. The coating composition of the present invention can be prepared by conventional methods. For example, the coating composition can be prepared by mixing the various components using a high speed shredding and dispersing equipment, such as a small medium mill. The present invention also provides a method of coating a metal substrate to provide a resilient and tough film on at least one surface of the substrate. The method includes applying the fluorocarbon polymer-based coating composition described above on a metal surface to form a resin film based on vinylidene difluoride and heating the coated surface to form a cured film adhered to the surface of the substrate. The coating composition can be applied to the surface of the substrate using a variety of well-known techniques. For example, the composition can be roller coated, bar coated or sprayed on the surface. The metal surface is generally coated with a fluoropolymer or acrylic based sizing coating, preferably a PVDF-containing sizing (such as a sizing based on a blend of PVDF and a hydroxy-functional acrylic copolymer) prior to the application of the composition. current coating. Many conventional sizes based on fluoropolymer and acrylic are known to those familiar in the art. Suitable examples of sizing which can be applied to a metal surface prior to the present compositions are described in U.S. Patent 4,684,677, the disclosure of which is incorporated herein by reference. Other suitable sizes include those based on commercially available acrylic emulsions, such as AC-1822 (available from Rohm & amp;; Hass), UCAR 452 and UCARMR 455 (available from Union Carbide Corp.), Joncryl ^ 537 (available from S.C. Johnson) and Sequabond ™ TR7830 (available from Sequa Chemicals, Chester, SC). When large, thin gauge metal rollers are to be coated, it is advantageous to apply the coating composition by means of a coil coating process, such as the reverse roller coating. When the coating is to be applied using such a process, the coated metal substrate is typically cured by heating for about 10 to about 50 seconds at a temperature of from about 200 ° C to about 300 ° C. If a spray coating process is to be used to apply the present composition, the resulting film is usually cured by heating for about 10 to about 15 minutes at a temperature of from about 210 ° C to about 270 ° C. The present composition is generally suitable for use in a coil coating and spray applications (e.g., a total solids content of from about 30 to about 70% by weight). However, if desired, the composition can be diluted before being applied by the addition of the solvent. For spray applications, an additional solvent such as xylene, toluene, methyl ethyl ketone or 2-butoxyethanol or the like can be added to reduce the resin solids content of the composition. The desired viscosity will vary based on the spray equipment and atmospheric conditions. When applied by means of spray methods, the pigmented versions of the present composition typically have a viscosity of 20-60 (# 2 Zahn) and a total solids content of from about 50 to about 70% by weight (total resin solids) from about 35 to about 50% by weight). Transparent versions of the present coating composition generally have a similar viscosity and contain a total resin solids content of from about 30 to about 45% by weight. Very often, the transparent versions are diluted to some degree with an organic solvent before spray application (for example, by the addition of 1 to 2 parts of butylcarbitol per 10 parts of the clear coating composition). The baking or heating temperatures are not critical, but must be high enough to cause the fluoropolymer particles, for example, the PVDF particles present in the dispersion to coalesce into a continuous film. A temperature of at least about 210 ° C for about 10 minutes will generally be adequate for this purpose. This temperature is more than sufficient to cure any polymer with hydroxy functionality present thereby providing improved solvent resistance and improved hardness. In coil coating processes, the oven standby temperature is often no more than about 30 seconds and oven temperatures as high as 300 ° C to 400 ° C can be used. Films based on vinylidene difluoride are preferably cured by baking them for a holding time of about 0.25 to 1.0 minutes so that the metal substrate reaches a metal peak temperature of 225 ° C to 260 ° C. The present invention can be further described with reference to the following examples. Unless otherwise indicated, the parts and percentages are parts and percentages by weight.

Ejgffplos The following abbreviations and trade names were used in the tables: TXIB-diisobutyrate of 2, 2, 4-trimethyl-l, 3-pentanediol; TEG-EH-triethylene glycol bis (2-ethyl hexanoate); PM Acetate - propylene glycol monomethyl ether acetate; DPM Acetate - dipropylene glycol monomethyl ether acetate; DMPhth - dimethyl phthalate; BuCell - ethylene glycol monobutyl ether; DBA - butylcarbitol acetate; DB-butylcarbitol; Isoph-isophorone; Disperplast ™ I - partial amides of higher molecular weight unsaturated polycarboxylic acids (available from BYK-Chemie, USA); Solsperse ^ 20000 ("S20") - an oxyalkylated aminoalcohol (available from Zeneca, Inc., Wilmington, DE); Solsperse ™ 28000 ("S28") - a polymeric polyester / polyamide condensate (available from Zeneca, Inc., Wilmington, DE); Therm-Chek ™ 130 - a mixture of barium and zinc salts available from Ferro Corp .; T150R1 - 1,2-ethanediamine polymer (available from BASF as Tetronic "701); T701 - oxyalkylated diamine (available from BASF as Tetronic" 11 OROR); FC-129 - Fluoroalkyl potassium carboxylate (available from 3M as Fluorad ™ FC-129); FSP - fluorinated phosphate ammonium salt (available from Dupont as Zonyl ™ FSP); F1176 - polyfluorosulfonic acid (available from Elf Atochem as Forafac ™ 1176); Blocked PTSA - p-toluenesulfonic acid amine salt; PTFE - polytetrafluoroethylene; Acrylic I - copolymer of methyl methacrylate / butyl acrylate / hydroxyethyl acrylate / methacrylic acid / 76: 18: 5: 1) with an Mw of 3000 to 10,000; Acrylic II - Acryloid ™ A21, methyl methacrylate thermoplastic copolymer / ethyl acrylate (available from Rohm &Haas, Philadelphia, PA); Acrylic III - copolymer of methyl methacrylate / butyl acrylate / hydroxyethyl acrylate / cric acid (75: 15.2: 9: 0.8) with an Mw of 35,000 to 65,000; and Acrylic IV - methyl methacrylate / ethyl acrylate / hydroxyethyl acrylate copolymer (70: 25: 5) with an Mw of 20,000 to 45,000.

Example lt Preparation of the coating composition A portion of the solvent and dispersant are combined under a mixer and stirred until the dispersant is completely dissolved. PVDF is then added under a high speed disperser and stirred at high speed for about 10 minutes. The mixture is then ground in a sand mill, a small medium mill or other suitable grinding equipment until a minimum crushing rating of 5.5 is obtained (Hegman scale). In a separate vessel, another portion of the solvent and the dispersant are combined as described above. The pigments are then added under the high speed disperser and stirred under high speed for about 10 minutes. This mixture is then ground in a sand mill, a small medium mill or other suitable grinding equipment until a minimum crushing reading of 6.5 (Hegman scale) is obtained. The pigment dispersion is then added to the PVDF dispersion and the resulting mixture is stirred under a high speed dispersion. Additional components of the formula (for example acrylic resin, melamine resin, blocked PTSA, micronized PTFE and / or solvents) are subsequently added under agitation. Viscosity and color adjustments are made by the addition of solvent and / or shading paste, as needed. The proportion of components present in numerous coating compositions of the present invention prepared by this process are shown in Tables I and II below.

Ejepplo 2: Movie and Property Generation The coating compositions were applied to aluminum with sizing or to a hot dipped galvanized metal substrate using either inverted pressing with a Bird bar or a wire wound roll, or spray application with a cup gun or other spray device suitable. The coated metal panel was then baked in a forced draft oven. The metal substrates used for the coil or slot application experiments were pretreated by coating the metal surface with Valspar Fluroprime ™ 732X323 or Valspar LK W0066 sizing to form a 2.5-10 micron sizing coat. (0.1-0.4 thousandths of an inch) thick. Metallic substrates used for spray application experiments were pretreated by coating the metal surface with Valspar Fluoprime ™ 733X310 sizing to form a size coat of 5 micrometers (0.2 mils) thick. The coating compositions A, B and C were applied to a sizing metal substrate using a procedure which simulated the slot coating. The coating compositions H, I and J were applied to a metallic substrate with sizing using a procedure which simulates the application by coil. The panels were coated using a Bird bar and then immediately baked in an oven at 296 ° C (565 ° F) for approximately 30 seconds of total standby time in oven to a metal peak temperature ("PMT") of approximately 249 ° C (480 ° F). After removal of the oven, the panel cooled rapidly (quenching) in a water bath at room temperature and dried by wiping. The coating compositions D-G and K-M were applied to a sizing metal substrate by spray application to form a wet PVDF film. The wet film was allowed to stand at room temperature for about 10 minutes and then placed in an oven at 232 ° C (450 ° F) for approximately 12 minutes of total standby time in the oven. After extraction from the oven, the panels were allowed to slowly cool to room temperature.

Table III shows the results of the physical characterizations of the films formed from the compositions described in example 1. The results of the T-bend test are reported as either OT (single roll, no ribbon release) or 1T (double roller, without detachment of tapes). The cured films showed excellent solvent resistance, hardness and impact resistance. Table IV shows a summary of the amounts of PVDF and total solids (NVM) in the compositions A-M. The amount of PVDF present is included both as a percentage of the total composition as well as a percentage of the total polymer components in the composition. The viscosities measured for numerous coating compositions are also presented. The corresponding information for two coatings based on commercial PVDFs are included for comparison purposes. The commercial winding formula is a 70% coating formulation of Kynar ™ sold by Valspar Corporation under the trade name Flurspon ™ Charcoal. The properties included for the commercial spray formula are for a 70% Kynar® coating formulation sold by Valspar Corporation under the tradename Fluropon "" Hartford Green which is diluted by adding 1 part xylene to 4 parts Fluropon ™. The results demonstrate that the present invention allows the production of coating formulations based on PVDF having solids loads of PVDF and / or total solids substantially higher than those obtainable with the current commercial formulations. The present invention allows high contents of PVDF and solids in pigmented formulations having a viscosity which allows application via winding or spraying techniques without prior reduction ("dilution") with a volatile solvent such as xylene or butylcarbitol.

Example 3t Comparison of Coil Coating A comparison of a commercial PVDF based coil coating formulation (70% Kynar ™) and an exemplary composition (H coating composition) of the present invention was carried out using a laboratory test designed to simulate coil coating conditions . Each of the sample coating compositions (0.6-0.7 g) was weighed into an aluminum weighing vessel 6.4 cm (2.5 inches) in diameter. The samples were diluted with approximately 2 ml of methyl ethyl ketone and dispersed evenly using a paper clip. The aluminum trays were placed in 0.3 mm (0.012 inch) thick aluminum sheet. The aluminum foil was first placed in a forced draft furnace at 104 ° C (220 ° F) for 1 minute, and then in a forced draft furnace at 329 ° C (625 ° F) for 30 seconds to obtain a metal peak temperature of 249 ° C (480 ° F). The samples are cooled to room temperature (for about 3 minutes) and the baked aluminum trays are reweighed. Determinations were made in triplicate for each composition. The% NVM (non-volatile component by weight) was calculated for each sample from the weight loss which occurred during baking. The values presented below are based on the average for the three determinations. The results show that the% NVM measured (50.9% by weight) for the commercial formulation of 70% winding Kynar ™ is essentially the same as the theoretical% NVM shown in Table IV (52.9% by weight). In other words, essentially all of the solvent component is volatilized from the commercial winding formulation at 70% Kynar "" during the firing conditions of the simulated winding. In contrast to the% NVM measured for composition H (76.8% by weight) after the simulated winding bake conditions which is substantially higher than the theoretical NVM% (62.4% by weight) for this composition. This indicates that only a portion (approximately 60%) of the 2,2,4-trimethyl-1,3-pentanediol diisobutyrate ("TXIB") as a solvent is lost during the baking of the PVDF-based coating. The remainder of TXIB is retained in the baked coating and acts as a plasticizer.

Ejepplo 4t Preparation of Transparent Coating Composition The solvent and the dispersant were combined under a high speed jet and stirred until the dispersant completely dissolved. PVDF was then added under the high speed disperser and stirred at high speed for about 10 minutes. The mixture was then milled in a sand mill, or other suitable grinding equipment until a minimum crushing rating of 5.5 (Hegman scale) is obtained. Additional components of the formula (for example acrylic resin, silica) were subsequently added under agitation. Viscosity adjustments were made by the addition of solvents as needed. The proportion of the components present in the three exemplary transparent coating compositions with high PVDF prepared by this process are shown in Table V below.

Example 5: Film and Property Generation Coating compositions N and Q were applied to a color coated aluminum metal substrate, with sizing via spray application with a cup barrel or other suitable spraying device. The coated metal panel was then baked in a forced draft furnace. The metal substrates were pretreated by coating the metal surface with a Valspar Fluroprime ™ primer to form a 5 micron (0.2 mil) thick primer coating, coating the aluminum substrate with sizing with a PVDF-based color coating (Valspar Fluropont ™ Premier Red Coat) and when baking in a forced draft oven at 232 ° C for approximately 12 minutes. Coating compositions N and Q were diluted by the addition of 1-2 parts of butylcarbitol and / or xylenes per 10 parts of coating composition and applied to the metal substrate coated with color, with sizing, by spray application to form a film based on wet PVDF with a thickness of 25 to 51 micrometers (1-2 thousandths of an inch) in thickness. The wet film was allowed to stand at room temperature for about 10 minutes and then placed in an oven at 232 ° C (450 ° F) for approximately 12 minutes of total standby time in the oven. After removal of the oven, the panels were allowed to cool slowly to room temperature.

Table VI shows the results of the physical characterizations of the films formed from the compositions N and Q. The included film thicknesses are the total film thicknesses covering the underlying sizing and the color coating. The cured films showed excellent solvent resistance, hardness and impact resistance. Table VII shows a summary of the amounts of PVDF and total solids (% by weight of NVM) in the compositions N and Q. The amount of PVDF present includes both as a percentage of the total composition and a percentage of the total polymer components in the composition. the composition. Also included are the measured viscosities of the coating compositions. The results demonstrate that the present invention allows the production of transparent coating formulations based on PVDF with substantially higher loads of PVDF than can currently be obtained with current commercial formulations. The present invention allows a high content of PVDF in clear topcoat formulations having viscosities which allow their application by means of spray techniques with a limited amount of reduction (for example "dilution" via the addition of 0.5-3 parts of the solvent such as butylcarbitol and / or xylenes, per 10 parts of coating composition) with a volatile solvent.

Example 6: PVDF / solvenhe / ispersant Combinations Examination The viscosity properties of numerous combinations of PVDF / dispersant / solvent were examined by measuring Brookfield viscosities (at 10 and 100 rpm) for formulations containing a standardized amount of solvent and dispersant. The resin portion of the formulations consisted solely of PVDF (either as 40.5% by weight or 50% by weight of PVDF). The formulations were prepared by placing the indicated test solvent in a high speed spout. The dispersant was weighed into the high speed jet and the mixture was stirred until the dispersant was cetely dissolved in the solvent. PVDF was added under stirring in the high speed spout and the mixture was stirred for an additional 5-10 minutes. Subsequently, the viscosity of the formulation was measured immediately in a Brookfield viscometer at 10 and 100 rpm. Table VIII shows the viscosities of numerous combinations based on the standard formula I (40.5% by weight of PVDF). Formula I contains 285 g of test solvent, 2.9 g of dispersant and 194 g of PVDF. The results shown in Table VIII suggest that polymeric dispersants having one or more amino groups covalently attached to the polymer (and specifically polymers in which at least one amino group is embedded in the polymer backbone) are particularly effective dispersants for the polymers. ester-based formulations having resin cnents with very high PVDF contents (as high as 100% by weight PVDF). Table IX shows the viscosities of numerous combinations based on the standard formula II (50% by weight of PVDF). Formula II contains 230 g of isophorone, 2.3 g of dispersant and 230 g of PVDF. The results shown in Table IX suggest that fluorinated anionic dispersants and polymeric dispersants having one or more amino groups covalently attached to the polymer are particularly effective dispersants for ketone-based formulations having resin cnents with very high PVDF contents ( as high as 100% by weight of PVDF).

Example 7: Critical Energies of Surfaces of Coated Panels Critical surface energies were determined for an example of a transparent coating formulation of the present invention containing 90% by weight of PVDF (on a resin solids base) and a commercial transparent PVDF coating formulation containing 70% in weight of PVDF. The csition with the transparent coating formulation with 90% by weight of PVDF ("R") is shown in Table V. The csition of the commercial transparent coating formulation with 70% by weight of PVDF ("8-1") is shown in table X. Metallic panels were tested with a coating formed of each of the two formulations for a feed contact angle using five different liquids (benzyl alcohol, ethylene glycol, diiodomethane, formamide and water) in an automated AlO goniometer. Kruss. The critical surface energy of each panel was determined by the Zisman method for each of the panels. The panel coated with the commercial formulation of 70% by weight of PVDF had a critical surface energy of 35.3 mN / m (dynes / cm). The panel coated with the 90% by weight formulation of PVDF had a critical surface energy of 32.3 mN / m. Lower surface energies have been linked to desirable coating characteristics such as reduced dirt collection and graffiti resistance. The untreated contact angles vary no more than 2 ° in each of the three-drop analyzes of a single panel, suggesting that the panel surfaces are coated very homogeneously. With the exception of the results obtained with water, the two panels differ significantly from each other. The difference of 3 nM / m in the critical surface energy is supported by the results with the other four liquids studied.

E epplo 81 Coating Formulation Compositions Table X below includes the components of three coating compositions. Compositions 8-2 and 8-3 are exemplary coatings in accordance with the present invention. Composition 8-1 is an example of commercial coating compositions with 70% by weight of PVDF provided for comparison purposes. Composition 8-2 is a white pigmented coating (based on Ti02) of PVDF which includes about 71% by weight of PVDF (on a resin solids base) together with two hydroxy-functional acrylic polymers. As indicated elsewhere in this document, the dispersant in this formulation (Solsperse ™ 2000) is particularly effective in formulations with clear and transparent colors, because it imparts excellent viscosity properties to the formulation without substantially increasing the propensity of the coating to yellowing The coating compositions 8-3 contain 100% by weight of PVDF in a base of resin solids at a high total charge of PVDF (48.5% by weight). The formulation is of a high content of pigmented PVDF, of a dark bronze color containing a polyester / polyamine dispersant (Solsperse ™ 28000). This formulation is notable for both the high percentage of PVDF in a resin solids base (100%) and the high total PVDF load (48.5% by weight).

TABLE I COATING COMPOSITIONS BASED ON PVDF COMPONENT A B D G H K Solvent TXIB 34.5 34.0 37.5 37.7 38.8 30.5 37.6 32.7 PM Acetate 1.5 1.5 1.8 4.0 2.1 Xylene. . 1.8 00 Dispersant Disperplast I 0.2 0.2 Thermchek 130 1.6 2.9 SolsperseMR 28000. 1.0 1.0 1.1 1.2 1.2 PVDF 42.1 41.5 43.1 43.0 36.0 35.3 41.1 40.3 Acrylic 2.7 2.7 3.2 7.1 3.7 Melamine Cymel 303 0.5 0.5 0.8 1.7 Cymel 380 1.1 PTSA blocked 0.04 0.04 • 0.02 0.02 - • Ti02 1.5 16.6 1.6 183 0.07 0.08 1.6 1.5 Yellow iron oxide 2.7 - 2.9 - - 2.8 2.7 1 Black ceramic 12.0 • 13.1 5.7 6.3 12.4 12.2 1 Red iron oxide 0.7. 0.8 0.7 0.7 Ceramic blue 6.0 6.6 • • 6.6 oxide green 7.3. micronized PTFE chrome 2.7 TABLE II COATING COMPOSITIONS BASED ON PVDF COMPONENT M Solvent TXIB 4.5 8.1 8.0 4.0 4.0 TEG-EH 26.8 Isoph 27.8 27.6 PM Acetate 2.1 30.8 DPM Acetate 28.7 Xylene 1.8 1.8 Dispersant SolsperseMR 28000 0.9 1.2 1.2 Dispersplast I - 0.2 0.2 - -Thermchek 130 0.2 0.6 - -Vinilacrylic 0.8 0.8 - - PVDF 47.0 44.9 44.7 40.3 40.3 Acrylic I - - 3.7 3.7 Melamine (Cymel 380) - - - 1.1 1.1 PTSA blocked - 0.04 0.04 - - TiO, 1.7 1.6 17.9 1.5 1.5 Yellow iron oxide 3.0 2.8 - 2.7 2.7 Black ceramic 13.7 12.8 - 12.2 12.2 Red iron oxide 0.8 0.8 - 0.7 0.7 Micronized PTFE 1.4 TABLE III PROPERTIES OF CURED FILM COMPOSITION DFT TOTAL METHOD BRIGHTNESS TO MEK DBL HARDNESS TO DOUBLE T (micrometers) FROM 60 ° RUBS PENCIL (thousandths of APPLICATION inch) To A 51 (2.0) slotted 35 > 150 B OT B 51 (2.0) slotted 37 > 150 B-HB OT C 127 (5.0) grooving 37 > 150 < B D 25 (1.0) sprinkler 32 > 150 HB F OT? I H E 36 (1.4) sprinkler 32 > 150 HB F OT F 33 (1.3) spray 25 > 150 F 1T G 43 (1.7) sprinkler 34 > 150 F 1T H 51 (2.0) winding 20 > 150 B OT 28 (1.1) winding 20 > 150 HB OT J 28 (1.1) winding 24 > 150 B-HB OT K 30 (1.2) aspersion 28 > 150 F OT L 30 (1.2) aspersion 28 • -M 30 (1.2) aspersion. .

TABLE IV Solids of Coating / Viscosity Compositions COMPOSITION% NVM% WEIGHT% OF VISCOSITY WEIGHT VISCOSITY Theory "* PVDF (PVDF composition (polymer (# 4 FORD). (. 112 ZAHN) total) A) 64.0 42.1 92.9 -B 64.5 41.5 92.8 - • C 68.7 47.0 100.0 - • D 62.5 43.1 100.0 41 E 62.3 43.0 100.0 70 • F 59.4 36.0 90.0 79 • G 65.5 35.3 80.0 - 59 H 62.4 41.1 100.0 60 • 64.1 44.9 100.0 36 J 64 4 4 7 100 0 47 K 63.2 40 3 89 8 35 L 63.2 40 3 89 4 35 M 63.2 40 3 89 4 28 Commercial Formula 52.9 26 6 70 0 89 Winding Commercial Formula 378 187 700 35 of Spray * Fluorontum Hartford Green was designed before spray application by addition of 0.25 xylene parts (per 1 part of coating); * * NVM -% theoretical weight of components does not volatilize.

TABLE V Transparent Coating Compositions with Elevated PVDF Component E Solvent DMPhth 22.1 20.6 22.5 BuOH 0.8 0.8 0.8 BuCell 6.9 7.1 7.0 PM Acetate 14.4 13.1 12.6 Toluene 18.7 20.1 19.1 Dispersant SolsperseMR 20000 0.042 0.043 0.04 PVDF 33.5 * 34.3"e 34.2 *** Acrylic II 3.5 3.6 3.6 Silica 0.05 0.3 0.1 * Kynar 500 Plus (Elf Atochem); ** Hylar MP-20 (Ausimont); *** Kynar 500 (Elf Atochem) TABLE VI Properties of Clear Coated Cured Film H O.

Total DFT (μm) (thousandths of an inch)) 41 (1. .6) 41 (1.6) Brightness at 60 ° 30 40 MEK DBL. RUBS > 150 > 150 Hardness of pencil H H Corvatura in T OT OT Rev. Impact 15 (inches-pound) 20 (inches-pound) TABLE VII Transparent Coating Composition Solids / Viscosity N O% by theoretical weight of NVM 37.0 38.2% by weight of PVDF 33.5 34.3 (total composition)% by weight of PVDF 90.5 90.5 (total polymer) Viscosity 73KU 74KU (Stormer) TABLE VIII Viscosities of the PVDF / Solvent / Dispersant Combinations Solvent / Dispersant Brookfield Brookfield index at 10 rpm at 100 rpm Thixotropic TXIB / - 13, 260 1, 910 6.9 TXIB / S28 190 100 1.9 TXIB / S20 3,160 630 5.0 TXIB / T701 15, 110 3, 846 3.9 TXIB / T150R1 360 146 2.5 TXIB / FC-129 10,400 1,466 7.1 TXIB / FSP 11, 100 1, 50 7.2 (insoluble) TXIB / F1176 insoluble DBA / - 1,150 270 4.3 DBA / S28 340 84 4.0 DBA / S20 900 198 4.5 DBA / FSP 8,500 1,220 7 DB / S28 2, 000 388 5.2 TABLE IX Viscosities of PVDF Combinations / Solvent / Dispersant Solvent / Dispersant Brookfield Brookfield index at 10 rpm at 100 rpm THIX Isoph / 4,520 700 6.5 Isoph (S20 2, 030 382 5.3 Isoph / S28 1, 200 258 4.7 Isoph / T701 2,250 414 5.4 Isoph / T150R1 1, 820 364 5 Isoph / F1176 300 104 2.9 Isoph / FC129 3,380 530 6.4 (partially soluble ) Isoph / FSP 320 112 2.9 TABLE X Coating Compositions Component 8-1 8-2 8-3 Solvent C8 Diol Diester 0 7.0 28.9 DMPhth 17.6 0.0 0.0 BuCell 12.8 0.0 0.0 MP Acetate 13.5 25.4 0.0 Toluene 10.0 0.0 0.0 DPM 0 12.3 0.0 Acetate of. butyl 0 0.2 0.0 Xylene 2.1 0 0.0 Dispersant Solsperse 20000 0 0.15 0.00 Solsperse 28000 0 0.00 1.13 PVDF 31.3 25.9 48.5 Acrylic I 0 4.2 0.0 Acrylic III 0 6.1 0.0 Acrylic IV 11.4 0.0 0.0 Isocyanate blocked 0 0.6 0.0 Melamine (Cymel 303LF) 1.2 0.0 0.0 Silica 0 0.3 0.0 PTFE 0 0.0 2.9 UNCLE. 0 17.7 1.6 Ceramic black 0 0.0 13.2 Iron oxide red 0 0.0 0.8 Yellow iron oxide 0 0.0 2.9 Total resin solids 42.7 36.2 48.5 % of PVDF (based on resin) 71.3 70.4 100.0 All publications and patent applications in this specification are indicative of the level of a person usually familiar with the technique to which this invention relates. All publications and patent applications are incorporated herein by reference to the same extent that each of the individual publications or patent applications is specifically and individually indicated as a reference. The invention has been described with reference to the various specific and preferred modalities and techniques. However, it should be understood that many other variations and modifications can be made and at the same time remain within the spirit and scope of the invention.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects or products to which it refers.

Claims (32)

1. CLAIMS Having described the invention as above, the content of the following claim 1 is claimed as property. A coating composition having a dispersed fluoropolymer resin, the composition is characterized in that it comprises: i) at least about 30% by weight in one Total composition base, polymer based on vinylidene difluoride; ii) an organic solvent; and iii) a hyperdispersant including a fluorinated anionic dispersant.
2. 2. The coating composition according to claim 1, characterized in that it comprises at least about 85% by weight of polyvinylidene difluoride in a base in resin solids.
3. 3. The coating composition according to claim 1, characterized in that the organic solvent comprises a non-aromatic ketone.
4. 4. The coating composition according to claim 1, characterized in that the organic solvent comprises isophorone.
5. 5. The coating composition according to claim 1, characterized in that the fluorinated anionic dispersant includes a salt of fluorinated alkylsulfonic acid, a partial ester salt of fluorinated alkyl phosphate or a mixture thereof.
6. 6. The coating composition according to claim 5, characterized in that the fluorinated alkylsulfonic acid salt comprises sulfonic acid salt having a formula: CnF. ^ - CaH.-SO / M * wherein n is an integer from 4 to 10, and M + is KX Na * or NH4X 7.
7. The coating composition according to claim 1, characterized in that it comprises from about 0.01 to about 30% by weight of the hyperdispersant.
8. The coating composition according to claim 1, characterized in that it comprises from about 85 to about 95% by weight of polyvinylidene difluoride in a base of resin solids, and from about 5 to about 15% by weight of acrylic polymer in a base of resin solids.
9. 9. The coating composition according to claim 1, characterized in that it also comprises an acrylic polymer.
10. 10. A coating composition having a dispersed fluoropolymer resin, the composition is characterized in that it comprises: i) at least about 30% by weight on a base of total polymer composition based on vinylidene difluoride; ii) an organic solvent that includes a non-aromatic ester, a non-aromatic ketone or a mixture thereof; and iii) a hyperdispersant including a polymeric dispersant having at least one amino group covalently attached to the polymer.
11. The coating composition according to claim 10, characterized in that it comprises at least about 85% by weight of polyvinylidene difluoride in a base of resin solids.
12. 12. The coating composition according to claim 10, characterized in that the organic solvent includes a non-aromatic ester.
13. 13. The coating composition according to claim 12, characterized in that the non-aromatic ester comprises an alkanediolyester having from 10 to 30 carbon atoms.
14. 14. The coating composition according to claim 12, characterized in that the solvent includes 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, dipropylene glycol methyl ether acetate, butylcarbitol acetate or a mixture thereof.
15. 15. The coating composition according to claim 10, characterized in that the polymeric dispersant includes a condensate of polymeric polyester / polyamine, oxyalkylated amine or a mixture thereof.
16. 16. The coating composition according to claim 15, characterized in that the oxyalkylated amine includes oxyalkylated ethanediamine, oxyalkylated inoalcohol or a mixture thereof.
17. 17. The coating composition according to claim 10, characterized in that it comprises from about 0.01 to about 3.0% by weight of the hyperdispersant.
18. The coating composition according to claim 10, characterized in that it comprises from about 85 to about 95% by weight of polyvinylidene difluoride in a base of resin solids, and from about 5 to about 15% by weight of acrylic polymer , in a base of resin solids.
19. 19. The coating composition according to claim 12, characterized in that the acrylic polymer comprises a thermoplastic acrylic polymer.
20. 20. The coating composition according to claim 10, characterized in that it comprises at least about 30% by weight of polyvinylidene difluoride in a base of total composition.
21. 21. The coating composition according to claim 10, characterized in that it comprises at least about 50% by weight of total solids.
22. 22. The coating composition according to claim 21, characterized by further comprising inorganic pigment.; wherein the coating composition has a # 2 Zahn viscosity of from about 25 to about 60 seconds.
23. 23. The coating composition according to claim 21, characterized in that it has a viscosity of Ford # 4 strain at 25 ° C from about 60 to about 120 seconds.
24. 24. The coating composition according to claim 22, characterized in that it includes from about 35% by weight to about 50% by weight of the polymer based on vinylidene difluoride and having a # 4 Ford cup viscosity at 25 ° C from about 80 to about 105 seconds.
25. 25. The coating composition according to claim 10, characterized in that the polymer based on vinylidene difluoride includes polyvinylidene difluoride having a Mu from about 350,000 to about 45,000, a Mw / Mr ratio from about 3.5 to about 5.0. , and a melting point of approximately 150-170 ° C.
26. 26. The coating composition according to claim 10, characterized in that it further comprises a polymer with hydroxy functionality and an aminoplast resin.
27. 27. The coating composition according to claim 10, characterized in that it comprises: (i) at least about 35% by weight of polyvinylidene difluoride in a base of total composition; (ii) from about 15 to about 25% by weight of organic pigment in a total composition base; and wherein at least about 50% by weight of the organic solvent has a boiling point between about 250 ° C and about 300 ° C.
28. 28. A composite material, comprising a metal substrate having at least one surface which includes a film based on fluoropolymer resin, formed by a process characterized in that it comprises: coating at least one surface with the coating composition in accordance with claim 1 to form a coated metal substrate; and heating the coated metal substrate.
29. 29. A coating composition having a dispersed fluoropolymer ream, characterized in that it comprises: i) at least about 30% by weight of polyvinylidene difluoride in a base of total composition; ii) organic solvent which includes dimethyl phthalate, toluene, ethylene glycol monobutyl ether, methyl ether propylene glycol acetate or a mixture thereof; iii) a hyperdispersant which includes oxyalkylated aminoalcohol; oxyalkylated polymeric ethanediamine or a mixture thereof; and iv) from about 5 to about 15% by weight of thermoplastic acrylic polymer in a base of resin solids.
30. 30. A coating composition having a dispersed fluoropolymer resin, characterized in that it comprises: i) at least about 35% by weight of polyvinylidene difluoride in a base of total composition; ii) organic solvent which includes isophorone; and iii) hyperdispersant which includes fluorinated alkylsulfonic acid salt, fluorinated alkyl phosphate partial ester salt, or a mixture thereof.
31. 31. A coating composition having a dispersed fluoropolymer resin, characterized in that it comprises: i) at least about 35% by weight of polyvinylidene difluoride in a base of total composition; ii) organic solvent which includes 2, 2, 4-trimethyl-1,3-pentanediol diisobutyrate, propylene glycol methyl ether, dipropylene glycol methyl ether, butylcarbitol acetate, or a mixture thereof; and iii) hyperdispersant which includes a polymeric polyester / polyamine condensate, oxyalkylated amine or a mixture thereof.
32. 32. A composite material, comprising a metal substrate having at least one surface which includes a film based on fluoropolymer resin formed by a process characterized in that it comprises: coating at least one surface with the coating composition in accordance with Claim 10 to form a coated metal substrate; and heating the coated metal substrate.