ACID CORES

FIELD

[0001] The invention generally relates to hyperbranched polymers and their use in coating compositions. In particular, aspects of the invention are directed to radiation- curable hyperbranched polymers with dicarboxylic acid cores, which are useful in radiation-curable coatings.

BACKGROUND

[0002] The solvents used in coatings and paints are a major source of man-made volatile organic compounds (VOC), which can have a negative impact on the environment. One approach to reducing the VOC of coatings is to utilize radiation-curable monomers or materials. These materials act as part of the carrier solvent for the other components of the coating formulation during application. After application onto the desired surface has been achieved, the coating is cured in situ by a free radical polymerization process typically initiated by a photoinitiator. Those radiation curable components are rendered non- volatile in the process. High conversion and high crosslink density are generally desired. However, limited mobility of unsaturated sites on monomers hinders the development of high conversion rates and builds stress into the film as crosslinks are formed, resulting in brittle film characteristics.

[0003] Hyperbranched polymers with available unsaturation can improve conversion rates and increase the number of crosslinks formed as well as relieve some stress in the film. However, standard hyperbranched polymers are somewhat limited with respect to the degree of flexibility they can bring to the cured film due to their radial architecture. There is thus a need for hyperbranched polymers that exhibit better flexibility, thereby imparting better film characteristics.

SUMMARY OF THE DISCLOSURE

[0004] One aspect of the invention pertains to a method of making a hyperbranched polymer. In one or more embodiments, the method comprises (a) obtaining a core comprising an esterification reaction product of:

(i) a dicarboxylic acid having structure HOOC-[C]n-COOH, wherein n is from 4 to 34; and

(ii) a polyol ; and

(b) optionally extending the core with one or more chain extenders to form an extended intermediate;

(c) reacting the core or the extended intermediate with a compound that comprises unsaturated free radical reaction sites to form the hyperbranched star polymer, wherein the compound is selected from the group consisting of: an anhydride comprising one or more unsaturated groups, an epoxide comprising one or more unsaturated groups, a lactone comprising one or more unsaturated groups, an isocyanate functional ester of (meth)acrylic acid, and combinations thereof; wherein the hyperbranched polymer is radiation-curable.

[0005] In or more embodiments, either the compound comprises the anhydride comprising one or more unsaturated groups that is directly reacted with the core; or the core is extended with a chain extender that comprises a saturated anhydride that is directly reacted with the core.

[0006] In some embodiments, the dicarboxylic acid comprises: adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid (brassylic acid), dodecanedioic acid, traumatic acid, hexadecanedioic acid (thapsic acid), octadecanedioic acid, tetradecanedioic acid, dimer fatty acids having 36 carbon atoms, or combinations thereof. In one or more embodiments, the polyol comprises: trimethylolpropane, pentaerythritol, a low molecular weight natural oil polyol, or combinations thereof. In some embodiments, the method further comprises increasing hydroxyl functionality of the core by reacting terminal hydroxyls of the core with a di- or polyhydric acid. In one or more embodiments, the dihydric acid comprises dimethylol propionic acid. In some embodiments, the compound comprises an unsaturated anhydride comprising: maleic anhydride, dodecenylsuccinic anhydride, or combinations thereof. In one or more embodiments, the dicarboxylic acid comprises adipic acid, the polyol comprises trimethylolpropane and the compound comprises an unsaturated anhydride that is maleic anhydride. In some embodiments, the dicarboxylic acid comprises adipic acid, the polyol comprises trimethylolpropane and the compound comprises an unsaturated anhydride that is octenylsuccinic anhydride.

[0007] Another aspect of the invention pertains to a method of making a hyperbranched polymer. In one or more embodiments, the method comprises

(a) esterifying a dicarboxylic acid having structure HOOC-[C]n-COOH, wherein n is from 4 to 34 with a polyol to form a core;

(b) reacting the core with a fully saturated anhydride to provide an extended intermediate; and

(cl) reacting the extended intermediate with an unsaturated epoxide-functional material or an isocyanate functional ester of (meth)acrylic acid and; or

(c2) reacting the extended intermediate with a fully saturated epoxide-functional material to provide a twice-extended intermediate; and (dl) reacting the twice-extended intermediate with an anhydride comprising an unsaturated group; or

(c2) reacting the extended intermediate with a fully saturated epoxide-functional material to provide a twice-extended intermediate and (d2) reacting the twice-extended intermediate with a saturated anhydride to provide a thrice-extended intermediate and (f) reacting the thrice-extended intermediate with an unsaturated epoxide-functional material.

[0008] In one or more embodiments, the method further comprises increasing hydroxyl functionality of the core by reacting terminal hydroxyls of the core with a di- or polyhydric acid. In some embodiments, the di-hydric acid comprises dimethylol propionic acid. In one or more embodiments, the method comprises (cl) reacting the extended intermediate with an unsaturated epoxide-functional material. In some embodiments, the unsaturated epoxide-functional material comprises glycidyl ester of (meth)acrylic acid. In one or more embodiments, dicarboxylic acid comprises adipic acid, the polyol comprises trimethylolpropane, the anhydride comprises hexahydrophthalic anhydride, and the unsaturated epoxide-functional material comprises glycidyl methacrylate. In some embodiments, the method comprises: (c2) reacting the extended intermediate with a fully saturated epoxide-functional material to provide a twice-extended intermediate; and (dl) reacting the twice-extended intermediate with an anhydride comprising an unsaturated group. In one or more embodiments, the fully saturated epoxide-functional material comprises glycidyl neodecanoate or glycidyl neononanoate. In some embodiments, the method comprises: (c2) reacting the extended intermediate with a fully saturated epoxide- functional material to provide a twice-extended intermediate; and (d2) reacting the twice- extended intermediate with a saturated anhydride to provide a thrice-extended intermediate and (f) reacting the thrice-extended intermediate with an unsaturated epoxide-functional material. In one or more embodiments, the fully saturated epoxide-functional material comprises glycidyl neodecanoate or glycidyl neononanoate.

[0009] Yet another aspect of the invention pertains to the polymers provided by the methods described herein.

[0010] Another aspect of the invention pertains to a method of producing a coating on a substrate surface. In one or more embodiments, the method comprises

(a) applying a coating composition comprising

(i) the hyperbranched polymer made by any of the methods described herein; and

(ii) a photoinitiator

to a substrate surface;

(b) curing the polymer in situ by free radical polymerization.

[0011] In some embodiments, curing comprises actinic radiation. In one or more embodiments, the photoinitiator is selected from the group consisting of diaryl ketone derivatives, benzoin alkyl ethers, alkoxy phenyl ketones, o-acylated oximinoketones, polycyclic quinones, benzophenones and substituted benzophenones, xanthones, thioxanthones, chlorosulfonyl and chloromethyl polynuclear aromatic compounds, chlorosulfonyl and chloromethyl heterocyclic compounds, chlorosulfonyl and chloromethyl benzophenones and fluorenones, haloalkanes and combinations thereof.

[0012] Another aspect of the invention pertains the coatings produced by the methods described herein.

BRIEF DESCRIPTION OF THE FIGURES

[0013] FIG. 1 is a chemical schematic of a compound in accordance with one or more embodiments of the invention; [0014] FIG. 2 is a chemical schematic of a compound in accordance with one or more embodiments of the invention; and

[0015] FIG. 3 is a chemical schematic of a compound in accordance with one or more embodiments of the invention.

DETAILED DESCRIPTION

[0016] Before describing several exemplary embodiments of the invention, it is to be understood that the invention is not limited to the details of construction or process steps set forth in the following description. The invention is capable of other embodiments and of being practiced or being carried out in various ways.

[0017] It has been surprisingly found that selection of certain components for the preparation of hyperbranched star polymers provide extra degrees of mobility and flexibility over traditional hyperbranched polymers. These hyperbranched star polymers permit creation of a higher crosslink density in radiation-cured films suitable for use on substrates which require flexibility and without the usual film stress. The higher crosslink density is thought translate into improved water barrier properties and improved thermal stability as well. The polymers according to one or more embodiments of the invention are hyperbranched, having multiple unsaturated sites that are predominantly located at the extremities of the polymer. These unsaturated sites are capable of free radical polymerization in a radiation cured system. The hyperbranched polymers comprise an aliphatic central core of between 6-36 carbons, which provides the polymer with a variably flexible core upon which the loci of unsaturation are free to rotate as well. While not wishing to be bound to any particular theory, it is thought that the combination of the flexible core and multiple functional groups at the extremities allow the polymer to help form durable and flexible radiation cured coatings.

[0018] Accordingly, one aspect of the invention pertains to a method of making a hyperbranched polymer. The method comprises

(a) obtaining a core comprising an esterification reaction product of:

(i) a dicarboxylic acid having structure HOOC-[C] _n -COOH, wherein n is from 4 to 34; and (ii) a polyol; and

(b) optionally extending the core with one or more chain extenders to form an extended intermediate;

(c) reacting the core or the extended intermediate with a compound that comprises unsaturated free radical reaction sites to form the hyperbranched star polymer, the compound being selected from the group consisting of: an anhydride comprising one or more unsaturated groups, an epoxide comprising one or more unsaturated groups, or an isocyanate functional ester of (meth)acrylic acid, and combinations thereof;

wherein the hyperbranched polymer is radiation-curable. As used herein throughout the specification, the term "hyperbranched" refers to a polymer having at least three branches from a core.

[0019] The first step of this aspect is (a) obtaining a core comprising an esterification reaction product of (i) a dicarboxylic acid having structure HOOC-[C] _n - COOH, wherein n is from 4 to 34; and (ii) a polyol. The hyperbranched polymer contains a central core by which the variable degree of flexibility is incorporated into the invention. After the dicarboxylic acid undergoes esterification with a polyol, the provided core contains multiple hydroxyl groups.

[0020] The dicarboxylic acid may be linear, branched, or cyclic. Non-limiting examples of suitable dicarboxylic acids include adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid (brassylic acid), dodecanedioic acid, traumatic acid, hexadecanedioic acid (thapsic acid), octadecanedioic acid, tetradecanedioic acid, and dimer fatty acids having 36 carbon atoms. In various embodiments, α,ω-dicarboxylic acids and dimer fatty acids having 36 carbon atoms are preferred. It is known that dimer fatty acids may have multiple isomers. Dimer fatty acids are commercially available, for example from BASF under the trademark EMPOL®, from Arizona Chemical under the trademark UNIDYME™, from Croda International Pic under the trademark Pripol™, and from Emery Oleochemicals as EMERY® Dimer Acids. Esterifiable derivatives of the dicarboxylic acids having from 6 to 36 carbon atoms include their mono- or diesters with aliphatic alcohols having 1 to 4 carbon atoms, preferably the methyl and ethyl esters, as well as the anhydrides.

[0021] In one or more embodiments, the dicarboxylic acid is the reaction product of a dioi with an anhydride, and may be produced in situ. For example, the dicarboxylic acid may be synthesized by the ring opening. In or more embodiments, a dicarboxylic acid useful for construction of the core component of the invention is synthesized by the ring- opening reaction of essentially two moles of a hexahydrophthalic anhydride with essentially one mole of a synthetic polyurethane diol (e.g., K-F!ex UD 320, made by King Industries). In such embodiments, the dicarboxylic acid is produced prior to esterification with the polyol.

[00221 As used herein, the term "polyol" refers to an alcohol having at least three hydroxyl functional groups available for reaction. The polyol may be selected from triols, dimers of triols, tetrols, dimers tetrols, and sugar alcohols. Nonlimiting examples of suitable polyols having three or more hydroxyl groups include glycerol, trimethylolmethane, trimethylolethane, trimethylolpropane, 2,2,3-trimethylolbutanc- 1 ,4- diol, 1 ,2,4-butanetriol, 1 ,2,6-hexanetri.ol, tris(hydroxymethyl)amine, t ri s( hyd rax ye t h y 1 )am i ne, t r i s( h yd rox y ro y 1 )am i n e, erythritol, pentaerythritoi, diglyceroi, trigiycerol or higher condensates of glycerol, di(trimethylol ropane), di(pentaerythritol), pentaerythritoi ethoxylate, pentaerythritoi propoxyiate, t ri s h yd ra ym ethyl isocyanurate, tris(hydroxyethyl) isocyanurate (THEIC), tris(hydroxypropyl) isocyanurate, inositols or sugars, such as glucose, fructose or sucrose, for example, sugar alcohols such as xylitol, sorbitol, mannitol, threitol, erythritol, adonitol (ribitol), arabitol (lyxitol), xylitol, duicitol (galactitol), maltitol, isomalt, polyetherols with a functionality of three or more, based on alcohols with a functionality of three reacted with ethylene oxide, propylene oxide and/or butylene oxide.

[0023] In some embodiments, examples of suitable polyols, include but are not limited to, trimethylolpropane, pentaerythritoi, and a low molecular weight natural oil polyol. As used herein a "low molecular weight" natural oil polyol refers to one with a molecular weight of less than about 2500 or 2000 MW. Examples of suitable low molecular weight natural oil polyols include, but are not limited to, castor oil derivatives. [0024] In various examples, the ratio in step (a) of moles of the polyol to moles of the dicarboxylic acid is from about 2.0 to about 2.5, preferably from about 2.0 to about 2.2, and more preferably from about 2.0 to about 2.07 moles of the polyol. per mole of the dicarboxylic acid. Particularly preferably, on average about one hydroxyl group of each polyol molecule is reacted with the dicarboxylic acid in step (a).

[0025] The esterification step (a) may be carried out by known, standard methods.

For example, this reaction is conventionally carried out at temperatures of between about 180°C and about 280°C in the presence, if desired, of an appropriate esterification catalyst. Typical catalysts for the esterification polymerization are protonic acids and Lewis acids, for example sulfuric acid, para-tol uenesu 1 ton ic acid, sulfates and hydrogen sulfates, such as sodium, hydrogen sulfate, phosphoric acid, phosphonic acid, hypophosphorous acid, titanium alkoxides, and dialkyltin oxides, for example dibutyltin oxide, dibutyltin dilaurate, lithium octanoate, under reflux with small quantities of a suitable solvent as entraining agent such as an aromatic hydrocarbon, for example xylene, or a (cyclo)aliphatic hydrocarbon, for example cyclohexane. As a non-limiting, specific example, the polyester may include stannous octoate or dibutyltin oxide. An acidic inorganic, organometallic, or organic catalyst can be used in a amount from. 0.1% to 10% by weight, preferably from 0.2% to 2% by weight, based on total weight of the reactants. It may be desirable to carry out the reaction step (a) free of catalyst to avoid or minimize side reactions during subsequent steps.

[0026] The esterification of step (a) can be carried out in bulk or in the presence of a solvent that is nonreactive toward the reactants. Nonlimiting examples of suitable solvents include hydrocarbons such as paraffins or aromatics. In some embodiments it may be preferred to use n-heptane, cyclohexane, toluene, ortho-xylene, meta-xylene, para- xylene, xylene isomer mixtures, ethylbenzene, chlorobenzene and ortho- and meta- dieh lorobenzene. The solvent may be used to aid in removing by-product of the esterification reaction azeotropically by distillation.

[0027] The amount of solvent that can. be used may be at least 0.1% by weight or at least 1 % by weight or at least 5% by weight, based on the weight of the starting reactants. Higher amounts of solvent may be used, but it is preferred to keep the concentration of reactants high, enough to permit the reaction to be carried out in a commercially viable length of time. Examples of ranges of the solvent that may be employed are from 0.1% to about 30% by weight, or from about 1% to about 15% by weight, or from, about 5%> to about 10% by weight, based in. each case on the weight of the starting reactants.

[0028] The reaction may be carried out in the presence of a water-removing agent, for example molecular sieves, especially molecular sieve 4 A, MgS0 ₄ and Na ₂ S0 ₄ .

[0029] The reaction of step (a) may be carried out at temperatures of 60 °C to 250

°C, for example at temperatures of 100 °C to 240 °C. In certain embodiments the reaction of step (a) may be carried out at temperatures of 150 °C to 235 °C. The reaction time depends upon, known factors, which include temperature, concentration of reactants, and presence and identity of catalyst, if any. Typical reactio times may be from about 1 to about 20 hours.

[0030] To minimize final volatile organic content, as much of the solvent used to azeotrope the byproduct from step (a) as is practical may be removed after completion of the reaction of step (a). Small amounts of solvents selected for their performance in the final resin can be used throughout the rest of the synthesis, for example as a flush following a reagent addition. Solvents that can react with anhydrides or epoxides, such as active hydrogen-containing compounds like hydroxy-functional solvents (e.g., alcohols and monoethers of glycols), are preferably avoided during both step (a) and subsequent reaction steps. After step (a), the reaction temperature is preferably kept below at temperature at which condensation-type esterification reactions could take place, for example kept below 150 °C, for the remainder of the synthesis to minimize the chance of condensation-type esterification reactions which, at this stage of the synthesis, would have undesirable effects on the molecular weight and architecture. For example, further esterification could produce unwanted branching or an undesirably increased molecular weight. The reaction temperature for steps subsequent to step (a) may be kept below 145 °C, below 140 °C, or even below 135 °C or 130 °C depending on whether a catalyst is used during step (a) and the nature of any catalyst used.

[0031] In one or more embodiments, the method may further comprise increasing the hydroxyl functionality of the core by reacting terminal hydroxyls of the core with a di- or polyhydric acid. Non-limiting examples of suitable dihydric and polyhydric acids include dimethylolpropionic acid, (DMPA), gluconic acid and lactobionic acid.

[0032] After providing the core, the core may (b) optionally be extended with one or more chain extenders to form an extended intermediate. In this step, the unsaturated free radical reaction sites on the radial structures are extended further away from the core. This extension of the eventual reactive unsaturation sites away from the core may be accomplished by the ring-opening reaction of fully saturated anhydrides with the hydroxyls of the core to provide the extended intermediate. The moles of fully saturated anhydride for extension would be < the equivalents of hydroxide available for reaction on the core. This ring-opening reaction may be accomplished at 150°C or less to minimize undesirable esterification reactions and can optionally be aided by the use of catalysts. This extended intermediate is a multicarboxyl functional hyperbranched intermediate. Non-limiting examples of suitable fully saturated anhydrides include hexahydrophthalic anhydride, succinic anhydride, phthalic anhydride, and methylhexahydrophthalic anhydride. Alternately, the extension of the eventual reactive unsaturation sites away from the core may be accomplished by the ring-opening reaction of a lactone ring compound with the hydroxyls of the core to provide the extended intermediate. The moles of lactone compound for extension may be determined by the equivalents of hydroxide available for reaction on the core and the number of lactone units away from the core it is desired to locate the reactive unsaturation group. This ring-opening reaction may be accomplished at 150°C or so and can optionally be aided by the use of catalysts. Non-limiting examples of suitable lactone ring compounds include ε-caprolactone, γ-caprolactone, β- butyrolactone, β-propriolactone, γ-butyrolactone, a-methyl-y-butyrolactone, βεγ- butyrolactone, γ-valerolactone, δ-valerolactone, e-decanolactone, δ-decanolactone, γ- nonanoic lactone, γ-octanoic lactone.

[0033] Subsequently to optional step (b), the core or the extended intermediate is reacted with a compound that comprises unsaturated free radical reaction sites to form the radiation curable hyperbranched star polymer, the compound being selected from the group consisting of: an anhydride comprising one or more unsaturated groups, an epoxide comprising one or more unsaturated groups, a lactone comprising one or more unsaturated groups, an isocyanate functional ester of (meth)acrylic acid, and/or combinations thereof, partly depending on the type of functional group available on the termini of the radial elements of the hyperbranched polymer. One way to append unsaturated functionality to terminal hydroxy functionality on the core, or optionally an extended intermediate, is to react the desired number of equivalents of hydro xyl on the molecule with an appropriate number of moles of a suitable unsaturated anhydride through a ring-opening reaction accomplished at < 150°C to avoid undesirable esterification reactions. Catalysts can be employed to aid the progress of the reaction. Non-limiting examples of suitable unsaturated anhydrides include maleic anhydride, dimethylmaleic anhydride, dodecenylsuccinic anhydride, 2-octen-ylsuccinic anhydride, oleic anhydride and erucic anhydride.

[0034] Another way to append unsaturated functionality to terminal hydroxy functionality on the core, or optionally an extended intermediate, is to react the desired number of equivalents of hydroxyl on the molecule with an appropriate number of moles of an isocyanate comprising one or more reactive ethylenically unsaturated sites. Thus, in some embodiments, the unsaturated functionality is appended to the hyperbranched polymer by a urethane linkage. These reactions are typically conducted at 20 to 80°C, but reaction conditions can be influenced by catalysts. Non-limiting examples of unsaturated isocyanate-functional materials include vinyl isocyanate, αα-dimethyl meta-isopropenyl benzyl isocyanate, isocyanatoethyl methacrylate, and isopropenyl isocyanate.

[0035] Yet another way to append unsaturated functionality to terminal hydroxy functionality on the core, or optionally an extended intermediate, is to react the desired number of equivalents of hydroxyl on the molecule with an appropriate number of moles of a lactone comprising one or more reactive ethylenically unsaturated sites. This ring- opening reaction may be accomplished at 150°C or so and can optionally be aided by the use of catalysts. Non-limiting examples of unsaturated lactone materials include 4- hydroxy-4-methyl-7-cz5-decenoic acid γ-lactone and 8-hydroxyoleic acid lactone.

[0036] One or more embodiments of the invention comprise appending the unsaturated functionality to terminal carboxylic acid functionality of an anhydride extended intermediate. This can be accomplished through the ring-opening reaction of an appropriate number of moles of an epoxide comprising one or more ethylenically unsaturated groups with the desired number of equivalents of carboxylic acid on the molecule. This ring-opening reaction may be accomplished at < 150°C to avoid undesirable esterification reactions. Catalysts can be employed to aid the progress of the reaction. Non-limiting examples of unsaturated epoxide materials include glycidyl methacrylate, glycidyl acrylate and oleyl glycidyl ether.

[0037] In one or more embodiments, either the compound comprises the anhydride comprising one or more unsaturated groups that is directly reacted with the core or the core is extended with a chain extender that comprises a saturated anhydride that is directly reacted with the core. In some embodiments, the compound comprises an unsaturated anhydride comprising: maleic anhydride, dodecenylsuccinic anhydride, or combinations thereof. In one or more embodiments, the dicarboxylic acid comprises adipic acid, the polyol comprises trimethylolpropane and the compound comprises an unsaturated anhydride that is maleic anhydride. In some embodiments, the dicarboxylic acid comprises adipic acid, the polyol comprises trimethylolpropane and the compound comprises an unsaturated anhydride that is octenylsuccinic anhydride.

[0038] Another aspect of the invention also pertains to method of making a hyperbranched polymer. The method comprises:

(a) esterifying a dicarboxylic acid having structure HOOC-[C] _n -COOH, wherein n is from 4 to 34 with a polyol to form a core;

(b) reacting the core with a fully saturated anhydride to provide an extended intermediate; and

(cl) reacting the extended intermediate with an unsaturated epoxide - functional material, or an isocyanate functional ester of (meth)acrylic acid; or (c2) reacting the extended intermediate with a fully saturated epoxide- functional material to provide a twice-extended intermediate; and (dl) reacting the twice-extended intermediate with an anhydride comprising an unsaturated group; or

(c2) reacting the extended intermediate with a fully saturated epoxide- functional material to provide a twice-extended intermediate and (d2) reacting the twice-extended intermediate with a saturated anhydride to provide a thrice-extended intermediate and (f) reacting the thrice- extended intermediate with an unsaturated epoxide-functional material.

[0039] As with the previous aspect, the first step (a) comprises esteri tying a dicarboxylic acid having structure HOOC-[C] _n -COOH, wherein n is from 4 to 34 with a polyol to form a core. The hyperbranched polymer contains a central core by which the variable degree of flexibility is incorporated into the invention. After the dicarboxylic acid undergoes esterification with a polyol, the provided core contains multiple hydroxyl groups.

[0040] The dicarboxylic acid may be linear, branched, or cyclic. Non-limiting examples of suitable dicarboxylic acids include adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid (brassylic acid), dodecanedioic acid, traumatic acid, hexadecanedioic acid (thapsic acid), octadecanedioic acid, tetradecanedioic acid, and dimer fatty acids having 36 carbon atoms. In various embodiments, α,ω-dicarboxylic acids and dimer fatty acids having 36 carbon atoms are preferred. It is known that dimer fatty acids may have multiple isomers. Dimer fatty acids are commercially available, for example from BASF under the trademark EMPOL®, from Arizona Chemical under the trademark UNIDYME™, from Croda International Pic under the trademark Pripol™, and from Emery Oleochemicals as EMERY® Dimer Acids. Esteri fi able derivatives of the dicarboxylic acids having from. 6 to 36 carbon atoms include their mono- or diesters with aliphatic alcohols having 1 to 4 carbon atoms, preferably the methyl and ethyl esters, as well as the anhydrides.

[0041] In one or more embodiments, the dicarboxylic acid is the reaction product of a diol with an anhydride, and may be produced in situ. In such embodiments, the dicarboxylic acid is produced prior to esterification with the polyol. Non-limiting examples of diols suitable for use in making a dicarboxylic acid in situ for the practice of this invention include -Flex UD 320-100. Non-limiting examples of anhydrides suitable for use in making a dicarboxylic in situ for the practice of this invention include he ahydrophthalic anhydride. [0042] As used herein, the term "polyol" refers to an alcohol having at least three hydroxyl functional groups available for reaction. The polyol may be selected from triois, dimers of triois, tetrois, dimers of tetrois, and sugar alcohols. Non-limiting examples of suitable polyols having three or more hydroxyl groups include glycerol, trimethylolmethane, trimethylolethane, trimcthylol propane, 2,2,3-trimethylolbutane- 1 .4- diol, 1 ,2,4-butanetriol, 1,2,6-hexanetriol, tris( hydro x ymeth y 1 )am inc. t ri s( hydroxyet h yl )am i ne, tris(hydroxypropyl)amine, erythritol, pentaerythritol, diglycerol, triglycerol or higher condensates of glycerol, diftrimethylolpropane), di(pentaerythritol ), pentaerythritol ethoxylate. pentaerythritol propoxylate, t ri s h yd ro ym et h y 1 isocyanurate, tris(hydroxyethyl) isocyanurate (THEIC), tris(hydroxypropyl) isocyanurate, inositols or sugars, such as glucose, fructose or sucrose, for example, sugar alcohols such as xylitol, sorbitol, mannitol, threitol, erythritol, adonitol (ribitol), arabitol (lyxitol), xylitol, duicitol (galactitol), maltitol, isomalt, polyetherols with a functionality of three or more, based on alcohols with a functionality of three reacted with ethylene oxide, propylene oxide and/or butylene oxide.

[0043] In some embodiments, examples of suitable polyols, include but are not limited to, trimethylolpropane, pentaerythritol, and a low molecular weight natural oil polyol. As used herein a "low molecular weight" natural oil polyol refers to one with a molecular weight of less than about 2500 or 2000 MW. Examples of suitable low molecular weight natural oil polyols include, but are not limited to, castor oil derivatives.

[0044] In various examples, the ratio in step (a) of moles of the polyol to moles of the dicarboxylic acid is from about 2.0 to about 2.5, preferably from about 2.0 to about 2.2, and more preferably from about 2.0 to about 2.07 moles of the polyol per mole of the dicarboxylic acid. Particularly preferably, on average about one hydroxyl group of each polyol molecule is reacted with the dicarboxylic acid in step (a).

[0045] The esterification step (a) may be carried out by known, standard methods.

For example, this reaction is conventionally carried out at temperatures of between about 180°C and about 280°C in the presence, if desired, of an appropriate esterification catalyst. Typical catalysts for the esterification polymerization are protonic acids and Lewis acids, for example sulfuric acid, para-tol uenesu 1 ton ic acid, sulfates and hydrogen sulfates, such as sodium, hydrogen sulfate, phosphoric acid, phosphonic acid, hypophosphorous acid, titanium alkoxides, and dialkyltin oxides, for example dibutyltin oxide, dibutyltin dilaurate, lithium octanoate, under reflux with small quantities of a suitable solvent as entraining agent such as an aromatic hydrocarbon, for example xylene, or a (cyclo)aliphatic hydrocarbon, for example cyclohexane. As a non-limiting, specific example, the polyester may include stannous octoate or dibutyltin oxide. An acidic inorganic, organometallic, or organic catalyst can be used in an amount from 0.1% to 10% by weight, preferably from 0.2% to 2% by weight, based on total weight of the reactants. It may be desirable to carry out the reaction step (a) free of catalyst to avoid or minimize side reactions during subsequent steps.

[0046] The esterification of step (a) can be carried out in bulk or in the presence of a solvent that is nonreactive toward the reactants. Non!imiting examples of suitable solvents include hydrocarbons such as paraffins or aromatics. In some embodiments it may be preferred to use n-heptane, cyclohexane, toluene, ortho-xylene, meta-xylene, para- xylene, xylene isomer mixtures, ethylbenzene, chlorobenzene and ortho- and meta- dichlorobenzene. The solvent may be used to aid in removing by-product of the esterification reaction azeotropically by distillation.

[0047] The amount of solvent that can be used may be at least 0.1% by weight or at least 1 % by weight or at least 5% by weight, based on the weight of the starting reactants. Higher amounts of solvent may be used, but it is preferred to keep the concentration of reactants high enough to permit the reaction to be carried out in a commercially viable length of time. Examples of ranges of the solvent that may be employed are from 0.1% to about 30% by weight, or from about 1%> to about 15% by weight, or from, about 5%o to about 10% by weight, based in each case on the weight of the starting reactants.

[0048] The reaction may be carried out in the presence of a water-removing agent, for example molecular sieves, especially molecular sieve 4 A, MgSO.t and Na ₂ S().i.

[0049] The reaction of step (a) may be carried out at temperatures of 60 °C to 250

°C, for example at temperatures of 100 °C to 240 °C. In certain embodiments the reaction of step (a) may be carried out at temperatures of 150 °C to 235 °C. The reaction time depends upon known factors, which include temperature, concentration of reactants, and presence and identity of catalyst, if any. Typical reaction tim.es may be from, about 1 to about 20 hours.

[0050] To minimize final volatile organic content, as much of the solvent used to azeotrope the byproduct from step (a) as is practical may be removed after completion of the reaction of step (a). Small amounts of solvents selected for their performance in the final resin can be used throughout the rest of the synthesis, for example as a flush following a reagent addition. Solvents that can react with anhydrides or epoxides, such as active hydrogen-containing compounds like hydroxy- functional solvents (e.g., alcohols and monoethers of glycols), are preferably avoided during both step (a) and subsequent reaction steps. After step (a), the reaction temperature is preferably kept below at temperature at which condensation-type esterification reactions could take place, for example kept below 150 °C, for the remainder of the synthesis to minimize the chance of condensation-type esterification reactions which, at this stage of the synthesis, would have undesirable effects on the molecular weight and architecture. For example, further esterification could produce unwanted branching or an undesirably increased molecular weight. The reaction temperature for steps subsequent to step (a) may be kept below 145 °C, below 140 °C, or even below 135 °C or 130 °C depending on whether a catalyst is used during step (a) and the nature of any catalyst used.

[0051] In one or more embodiments, the hydroxyl functionality of the core may be increased by reacting terminal hydroxyls of the core with a di- or polyhydric acid. In further embodiments, the dihydric acid comprises dimethylol propionic acid.

100521 Next, in step (b), the core is reacted with a fully saturated anhydride to provide an extended intermediate. In this step, the unsaturated free radical reaction sites on the radial structures are extended further away from the core by the reaction of the fully saturated anhydrides with the hydroxyls of the core to provide the extended intermediate. This extended intermediate is a multicarboxyl functional hyperbranched intermediate. The extended intermediate allows to locate the unsaturated free radical reaction sites of the final molecule away from the core out onto the radial elements of the molecule. In this step, the chain extensions can be achieved by the reaction of a saturated anhydride with the hydroxy functionality of the core. This extended intermediate is a multicarboxyl functional hyperbranched intermediate. Alternatively, the chain extensions can be achieved by the reaction of a saturated lactone with the hydroxy functionality of the core yielding an intermediate with hydroxy functionality on radial elements extending from the core.

[0053] This extension of the eventual reactive unsaturation sites away from the core may be accomplished by the ring-opening reaction of fully saturated anhydrides with the hydroxyls of the core to provide the extended intermediate. The moles of fully saturated anhydride for extension would be < the equivalents of hydroxide available for reaction on the core. This ring-opening reaction may be accomplished at 150°C or less to minimize undesirable esterification reactions and can optionally be aided by the use of catalysts. Alternatively, this extension of the eventual reactive unsaturation sites away from the core may be accomplished by the ring-opening reaction of fully saturated lactones with the hydroxyls of the core to provide the extended intermediate. The moles of fully saturated anhydride for extension would be < the equivalents of hydroxide available for reaction on the core to eventually place the reactive unsaturated sites one lactone chain-length away from the core. Further extension will result by using more equivalents of the saturated lactone component. This lactone ring-opening reaction can be accomplished at about 150°C or less to minimize undesirable esterification reactions and can optionally be aided by the use of catalysts.

[0054] In a specific embodiment, the dicarboxylic acid comprises adipic acid, the polyol comprises trimethylolpropane, the anhydride comprises hexahydrophthalic anhydride, and the unsaturated epoxide-functional material comprises glycidyl methacrylate.

[0055] After step (b), there are three options for further reaction of the extended intermediate. The first is to (cl) react the extended intermediate with an unsaturated epoxide-functional material. In (cl), a variable number of the multiple, terminal carboxyl groups of the second intermediate are reacted with an unsaturated epoxide-functional material to provide unsaturated sites through which to participate in radiation-initiated free radical polymerization.

[0056] For example, the epoxide-functional material may be an epoxy ester, also known as a glycidyl ester. Unsaturated glycidyl esters can be prepared by reacting an unsaturated carboxylic acid with, an epihalohydrin (e.g., cpich!orohydrin) under conditions well known in the art. Examples of glycidyl esters include, but are not limited to, glycidyl aery I ate and glycidyl methacrylate. Among useful glycidyl esters are those having an ally! group having from 7 to 17 carbon atoms. Another useful class of monoepoxides is glycidyl ethers. Glycidyl ethers can be prepared by the reaction of monofunctional unsaturated alcohols with an epihalohydrin (e.g., epichlorohydrin). Non-limiting examples of unsaturated epoxide materials include glycidyl methacrylate, glycidyl acrylate and oleyl glycidyl ether.

[0057] The equivalent ratio of carboxylic acid groups of the second intermediate product to epoxide groups of the epoxide-functional compound may be from about 1.0 to about 2.5, or from about 1.0 to about 2.0, or from about 1.0 to about 1.5, or from, about 1.0 to about 1.3, or from, about 1.0 to about 1.1 equivalents of carboxylic acid groups per equivalents epoxide grou s. The preferred range of equivalents of carboxylic acid groups to epoxide groups will vary, however, depending on whether the embodiment will be for a solventborne or waterborne coating composition. In one embodiment, the hyperbranched polyol is used in a solventborne coating composition and every, or substantially every, carboxyl. group of the second intermediate product is reacted with a monoepoxide compound. In other embodiments, on average some of the carboxyl groups are left unreacted and may be neutralized, for example with ammonia, an amine, or another base in forming a waterborne coating composition.

[0058] In one or more embodiments, reacting the extended intermediate with unsaturated epoxide comprises a ring-opening reaction of an appropriate number of moles of an epoxide comprising one or more ethylenically unsaturated groups with the desired number of equivalents of carboxylic acid on the molecule. This ring-opening reaction may be accomplished at < 150°C to avoid undesirable esterification reactions. Catalysts can optionally be employed to aid the progress of the reaction.

[0059] Alternatively. (c2) the extended intermediate may be reacted with a fully saturated epoxide-functional material to provide a twice-extended intermediate. Step (c2) allows for the radial structure of the disclosed polymers to be further extended away from the core, before appending the free radically reactive unsaturated sites. It also allows for the incorporation of new structural elements onto the radial elements of the polymer and changes the chemical reactivity characteristics of the extended intermediate. To that end, a fully saturated epoxide functional material may be reacted with a variable number of the multiple terminal carboxyl groups of the second intermediate described above to create a twice-extended intermediate, now comprising reactive hydroxyl groups again.

[0060] For example, the epoxide-functional material may be an epoxy ester, also known as a glycidyl ester. Glycidyl esters for (c2) can be prepared by reacting a saturated carboxylic acid with an epihaiohydrin (e.g., epichlorohydrin) under conditions well known in the art. Suitable saturated epoxide materials for making this third intermediate would include, but not be limited to, glycidyl neodecanoate or glycidyl neononanoate. Among useful glycidyl esters are those having an alkyl group having from 7 to 17 carbon atoms. A particularly preferred glycidyl ester is a glycidyl ester of a saturated synthetic tertiary monocarboxylic acid having 9-11 carbon atoms. In a preferred embodiment, the monofunctionai carboxylic acid used to produce the glycidyl esters is a neoalkanoic acid such as, without limitation, neodecanoic or neononanoic acid. Glycidyl esters of neoacids are commercially available from Momentive Specialty Chemicals Inc. under the name of CarduraTM.

[0061] Another useful class of monoepoxides is glycidyl ethers. Glycidyl ethers can be prepared by the reaction of monofunctionai alcohols (e.g., n-butano!, propanoi, 2- ethylhexanol, dodecanol, phenol, cresol, cyclohexanol, benzyl alcohol) with an epihaiohydrin (e.g., epichlorohydrin). Useful glycidyl ethers include, but are not limited to, methyl glycidyl ether, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, pentyl glycidyl ether, hexy! glycidyl ether, heptyl glycidyl ether, octyl glycidyl ether, nonyl glycidyl ether, decyl glycidyl ether, undecyl glycidyl ether, dodecyl glycidyl ether, tridecyi glycidyl ether, tetradecyi glycidyl ether, pentadecyl glycidyl ether, hexadecyl glycidyl ether, heptadecyl glycidyl ether, octadecyl glycidyl ether, nonadecyi glycidyl ether, eicosyl glycidyl ether, heneicosyl glycidyl ether, docosyl glycidyl ether, tricosyl glycidyl ether, tetracosyl glycidyl ether, and pentacosyl glycidyl ether.

[0062] The equivalent ratio in step (c) of carboxylic acid groups of the second intermediate product to epoxide groups of the epoxide-functional compound may be from about 1.0 to about 2.5, or from, about 1.0 to about 2.0, or from about 1.0 to about 1.5, or from, about 1.0 to about 1.3, or from, about 1.0 to about 1.1 equivalents of carboxylic acid groups per equivalents epoxide groups. The preferred range of equivalents of carboxylic acid groups to epoxide groups will vary, however, depending on whether the embodiment will be for a solventborne or waterborne coating composition, in one embodiment, the hyperbranched polyol is used in a solventborne coating composition and every, or substantially every, carboxyl group of the second intermediate product is reacted with a monoepoxide compound. In other embodiments, on average some of the carboxyl groups are left unreacted and may be neutralized, for example with ammonia, an amine, or another base in forming a waterborne coating composition.

[0063] Reacting the extended intermediate with saturated epoxide may be accomplished via ring-opening reaction at < 150°C to avoid undesirable esterification reactions. Catalysts can optionally be employed to aid the progress of the reaction.

10064] The equivalent ratio of carboxylic acid groups of the second intermediate product to epoxide groups of the epoxide-functional compound may be from about 1.0 to about 2.5, or from about 1.0 to about 2.0. or from about 1.0 to about 1.5, or from about 1.0 to about 1.3, or from, about 1.0 to about 1.1. equivalents of carboxylic acid groups per equivalents epoxide groups. The preferred range of equivalents of carboxylic acid groups to epoxide groups will vary, however, depending on whether the embodiment will be for a solventborne or waterborne coating composition. In one embodiment, the hyperbranched polyol is used in a solventborne coating composition and every, or substantially every, carboxyl group of the second intermediate product is reacted with a monoepoxide compound. In other embodiments, on average some of the carboxyl groups are left unreacted and may be neutralized, for example with ammonia, an amine, or another base in forming a waterborne coating composition.

[0065] After step (c2), there are two options. The first is to (dl) react the twice- extended intermediate with an anhydride comprising an ethylenically unsaturated group. The subsequent reaction of an unsaturated anhydride with the hydroxyl groups of the twice- extended intermediate allows for incorporation of unsaturated, free radically reactive sites. Examples of suitable unsaturated anhydrides would include, but are not limited to, maleic anhydride, dodecenylsuccinic anhydride, and octenylsuccinic anhydride. Examples of suitable unsaturated epoxides would include, but are not limited to glycidyl methacrylate, glycidyl acrylate and oleyl glycidyl ether. Non-limiting examples of unsaturated lactone materials include 4-hydroxy-4-methyl-7-czs-decenoic acid γ-lactone and 8-hydroxyoleic acid lactone.

[0066] These ring-opening reactions may be accomplished at < 150°C to avoid undesirable esterification reactions. Catalysts can optionally be employed to aid the progress of the reaction.

[0067] Alternatively, (d2) the twice-extended intermediate may be reacted with a saturated anhydride to provide a thrice-extended intermediate, followed by (f) reacting the thrice-extended intermediate with an unsaturated epoxide-functional material. Additional unsaturation functionality and extension can be added by reaction of all or some of the hydroxyl groups of the twice-extended intermediate with a saturated anhydride, such as HHP A, then reacting some or all of the newly appended carboxyl groups with a suitable unsaturated epoxide, such as the glycidyl ester of acrylic or methacrylic acid, in a specific embodiment, the fully saturated epoxide-functional material comprises glycidyl neodecanoate or glycidyl neononanoate.

[0068] The flexible hyperbranched polymers according to one or more embodiments of the invention have several advantages. The polymers may facilitate the use of flexible hyperbranched polymers with a high potential for crosslinking in radiation cured coating systems. Additionally, the hydrophobic component in the central core builds hydrophobic character to the cured film, which may improve the water resistance of the final cured coating. The aliphatic chain in the central core provides the polymer with a flexibility characteristic which is independent of the participation of the polymers in crosslinking reactions. Thus, the flexibility of the resulting crosslinked film is not sacrificed to achieve higher crosslink density.

[0069] Moreover, by adjusting the length of the aliphatic chain in the core, the flexibility of the invention, and so the resulting final film, can be modulated. The unsaturated groups located at the periphery of the polymers provide numerous active crosslinking sites for radiation induced free radical polymerization, which allow the polymer to be formulated into durable coatings, as discussed above. Additionally, the architecture of the polymers allows appending hydrophobic "extension" chains which will increase the non-volatile content without greatly increasing the viscosity of the polymer, which allows making coating formulations with a lower VOC.

Coating compositions

[0070] The hyperbranched, unsaturated bridged-star polymers of one or more embodiments of the invention may be formulated with other radiation-curable components and essential elements of radiation-curable coatings, (such as photoinitiators), applied to a substrate in accord with methods typical for radiation-cured coatings and cured utilizing actinic radiation appropriate to activate whichever photoinitiator is being used.

[0071] Accordingly, another aspect of the invention pertains to methods of producing a coating on a substrate surface, as well as to the coatings produced by these methods. As will be discussed further below, the method may comprise applying a coating composition comprising any one of the hyperbranched polymers described above to substrate surface. In further embodiments, the coating composition may further comprise a photoinitiator. In yet further embodiments, the method further comprises curing the polymer in situ by free radical polymerization {e.g. curing using actinic radiation).

[0072] A desired amount of any of the hyperbranched polyois described above may be included in a coating composition. The amount of the hyperbranched po!yol included may vary depending on the characteristics of other coating components and the desired overall balance of performance characteristics of the coating obtained from the coating composition. In various examples, the coating composition may include from about 5% to about 60% by weight, or from about 5% to about 50% by weight, or from about 5% to about 45%) by weight, or from about 10%> to about 50%> by weight, or from about 10%> to about 45%o by weight, or from about 10%> to about 40%> by weight, or from about 10%> to about 35%) by weight, or from about 15% to about 40%> by weight, or from about 15% to about 35% by weight of the hyperbranched polyol based on the total amount of film- forming materials (also called the binder or vehicle of the coating composition).

[0073] The coating composition may include other reactive resins or polymers. Examples of useful resins or polymers include (meth)acrylate polymers (also known as acrylic polymers or resins), polyesters, polyetliers, polyurcthancs, polyols based on natural oils, such as those available under the trademark Polycins from Vertellus Specialties Inc., Indianapolis, IN, for example a polyol based on castor oil, polysiloxanes, and those described in Mormile et al., US Patent No. 5,578,675; Lane et al., US Patent Application Publication No. 201 1/0135,832; and Groenewolt et al, U.S. Patent Application Publication No. 2013/0136865, each of which is incorporated herein by reference. The other resins or polymers may have functionality reactive with the crossl inker for the hyperbranched polyol, or that the coating composition may contain a further crossl inker for the other resins or polymer. In certain preferred examples, the coating composition includes a further resin or polymer having hydroxyl groups, carbamate groups, or a combination of such groups. In various embodiments, the coating composition contains a hydroxyl-functional acrylic polymer, hydroxyl-functional polyester, or hydroxyl-functional polyurethane.

[0074] Polyvinyl polyols, such as acrylic (polyacrylate) polyol polymers that may be used as the hydroxy-functional material. Acrylic polymers or polyacrylate polymers may be copolymers of both acrylic and methacrylic monomers as well as other copolymerizable vinyl monomers. The term "(meth)acrylate" is used for convenience to designate either or both acrylate, and methacrylate, and the term "(meth)acrylic" is used for convenience to designate either or both acrylic and methacrylic.

[0075] Hydroxyl-containing monomers include hydroxy alkyl esters of acrylic or methacrylic acid. Nonlimiting examples of hydroxyl-functional monomers include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylates, hydroxybutyl (meth )acrylates, hydroxyhexyl (meth )acrylates, propylene glycol mono(meth)acrylate, 2,3-dihydroxypropyl (meth)acrylate, pentaerythritol monoi met h )acry 1 ate, polypropylene glycol mono( met h )acry 1 atcs, polyethylene glycol mono(meth)acrylates, reaction products of these with epsilon-caprolactone, and other hydroxyalkyl (meth )acrylates having branched or linear alkyl groups of up to about 10 carbons, and mixtures of these, where the term "(meth)acrylate" indicates either or both of the methacrylate and acrylate esters. Generally, at least about 5% by weight hydroxyl-functional monomer is included in the polymer. Hydroxyl groups on a vinyl polymer such as an acrylic polymer can be generated by other means, such as, for example, the ring opening of a glycidyl group, for example from copolymerized glycidyl methacrylate, by an organic acid or an amine. Hydroxyl functionality may also be introduced through thio-alcohol compounds, including, without limitation, 3-mercapto-l-propanol, 3-mercapto-2-butanol, 11-mercapto-l-undecanol, 1- mercapto-2-propanol, 2-mercaptoethanol, 6-mercapto-l-hexanol, 2-mercaptobenzyl alcohol, 3-mercapto-l,2-proanediol, 4-mercapto-l -butanol, and combinations of these. Any of these methods may be used to prepare a useful hydroxyl-functional acrylic polymer.

[0076] Examples of suitable comonomers that may be used include, without limitation, α,β-ethylenically unsaturated monocarboxylic acids containing 3 to 5 carbon atoms such as acrylic, methacrylic, and crotonic acids and the alkyl and cycloalkyl esters, nitriles, and amides of acrylic acid, methacrylic acid, and crotonic acid; α,β-ethylenically unsaturated dicarboxylic acids containing 4 to 34 carbon atoms and the anhydrides, monoesters, and diesters of those acids; vinyl esters, vinyl ethers, vinyl ketones, and aromatic or heterocyclic aliphatic vinyl compounds. Representative examples of suitable esters of acrylic, methacrylic, and crotonic acids include, without limitation, those esters from reaction with saturated aliphatic alcohols containing 1 to 20 carbon atoms, such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, hexyl, 2-ethylhexyl, dodecyl, 3,3,5-trimethylhexyl, stearyl, lauryl, cyclohexyl, alkyl-substituted cyclohexyl, alkanol- substituted cyclohexyl, such as 2-tert-butyl and 4-tert-butyl cyclohexyl, 4-cyclohexyl-l- butyl, 2-tert-butyl cyclohexyl, 4-tert-butyl cyclohexyl, 3,3,5,5,-tetramethyl cyclohexyl, tetrahydrofurfuryl, and isobornyl acrylates, methacrylates, and crotonates; unsaturated dialkanoic acids and anhydrides such as fumaric, maleic, itaconic acids and anhydrides and their mono- and diesters with alcohols such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, and tert-butanol, like maleic anhydride, maleic acid dimethyl ester and maleic acid monohexyl ester; vinyl acetate, vinyl propionate, vinyl ethyl ether, and vinyl ethyl ketone; styrene, a-methyl styrene, vinyl toluene, 2-vinyl pyrrolidone, and p- tert-butylstyrene .

[0077] The acrylic polymer may be prepared using conventional techniques, such as by heating the monomers in the presence of a polymerization initiating agent and optionally a chain transfer agent. The polymerization may be carried out in solution, for example. Typical initiators are organic peroxides such as dialkyl peroxides such as di-t- butyl peroxide, peroxyesters such as t-butyl peroxy 2-ethylhexanoate, and t-butyl peracetate, peroxydicarbonates, diacyl peroxides, hydroperoxides such as t-butyl hydroperoxide, and peroxyketals; azo compounds such as 2,2'azobis(2- methylbutanenitrile) and l,l '-azobis(cyclohexanecarbonitrile); and combinations of these. Typical chain transfer agents are mercaptans such as octyl mercaptan, n- or tert-dodecyl mercaptan; halogenated compounds, thiosalicylic acid, mercaptoacetic acid, mercaptoethanol and the other thiol alcohols already mentioned, and dimeric alpha-methyl styrene.

[0078] The reaction is usually carried out at temperatures from about 20°C to about 200°C. The reaction may conveniently be done at the temperature at which the solvent or solvent mixture refluxes, although with proper control a temperature below the reflux may be maintained. The initiator should be chosen to match the temperature at which the reaction is carried out, so that the half-life of the initiator at that temperature should preferably be no more than about thirty minutes. Further details of addition polymerization generally and of polymerization of mixtures including (meth)acrylate monomers is readily available in the polymer art. The solvent or solvent mixture is generally heated to the reaction temperature and the monomers and initiators) are added at a controlled rate over a period of time, usually between 2 and 6 hours. A chain transfer agent or additional, solvent may be fed in also at a controlled rate during this time. The temperature of the mixture is then maintained for a period of time to complete the reaction. Optionally, additional initiator may be added to ensure complete conversion.

[0079] Oligomeric and polymeric ethers may be used, including diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, dipropylene glycol, tripropylene glycol, linear and branched polyethylene glycols, polypropylene glycols, and block copolymers of poly( ethylene oxide-co-propylene oxide). Other polymeric polyols may be obtained by reacting a polyol initiator, e.g., a diol such as 1,3-propanediol or ethylene or propylene glycol or a polyol such as trimethylolpropane or pentaerythritol, with a lactone or alkylene oxide chain-extension reagent. Lactones that can be ring opened by active hydrogen are well known in the art. Examples of suitable lactones include, without limitation, ε-caprolactone, γ-caprolactone, β-butyrolactone, β-propriolactone, γ- butyrolactone, a-methyl-y-butyrolactone, β -methyl -γ-butyrolactone, γ-valerolactone, δ- valerolactone, γ-decanolactone, δ-decanolactone, γ-nonanoic lactone, γ-octanoic lactone, and combinations of these. In one preferred embodiment, the lactone is ε-caprolactone. Useful catalysts include those mentioned above for polyester synthesis. Alternatively, the reaction can be initiated by forming a sodium salt of the hydroxyl group on the molecules that will react with the lactone ring. Similar polyester polyols may be obtained by reacting polyol initiator molecules with hydroxy acids, such as 12-hydroxystearic acid.

[0080] In other embodiments, a polyol initiator compound may be reacted with an oxirane-containing compound to produce a polyether diol to be used in the polyurethane elastomer polymerization. Alkylene oxide polymer segments include, without limitation, the polymerization products of ethylene oxide, propylene oxide, 1 ,2-cyclohexene oxide, 1- butene oxide, 2-butene oxide, 1-hexene oxide, tert-butylethylene oxide, phenyl glycidyl ether, 1-decene oxide, isobutylene oxide, cyclopentene oxide, 1-pentene oxide, and combinations of these. The oxirane-containing compound is preferably selected from ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, and combinations of these. The alkylene oxide polymerization is typically base-catalyzed. The polymerization may be carried out, for example, by charging the hydroxyl-functional initiator compound and a catalytic amount of caustic, such as potassium hydroxide, sodium methoxide, or potassium tert-butoxide, and adding the alkylene oxide at a sufficient rate to keep the monomer available for reaction. Two or more different alkylene oxide monomers may be randomly copolymerized by coincidental addition or polymerized in blocks by sequential addition. Homopolymers or copolymers of ethylene oxide or propylene oxide are preferred. Tetrahydrofuran may be polymerized by a cationic ring-opening reaction using such counterions as SbF ₆ , AsF ₆ , PF ₆ , SbCl ₆ , BF ₄ , CF3SO3 , FSO3 , and C10 ₄ . Initiation is by formation of a tertiary oxonium ion. The polytetrahydrofuran segment can be prepared as a "living polymer" and terminated by reaction with the hydroxyl group of a diol such as any of those mentioned above. Polytetrahydrofuran is also known as polytetramethylene ether glycol (PTMEG). Any of the polyols mentioned above maybe employed as the polyol initiator and extended in this fashion. [0081] Nonlimiting examples of suitable polycarbonate polyols that might be used include those prepared by the reaction of polyols with dialkyl carbonates (such as diethyl carbonate), diphenyl carbonate, or dioxolanones (such as cyclic carbonates having five- and six-member rings) in the presence of catalysts like alkali metal, tin catalysts, or titanium compounds. Useful polyols include, without limitation, any of those already mentioned. Aromatic polycarbonates are usually prepared from reaction of bisphenols, e.g., bisphenol A, with phosgene or diphenyl carbonate. Aliphatic polycarbonates may be preferred for a higher resistance to yellowing, particularly when the carbamate-functional material is used in an automotive OEM or refmish topcoat.

[0082] Polyesters polyols may be prepared by reacting: (a) polycarboxylic acids or their esterifiable derivatives, together if desired with monocarboxylic acids, (b) polyols, together if desired with monofunctional alcohols, and (c) if desired, other modifying components. Nonlimiting examples of polycarboxylic acids and their esterifiable derivatives include phthalic acid, isophthalic acid, terephthalic acid, halophthalic acids such as tetrachloro- or tetrabromophthalic acid, adipic acid, glutaric acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, trimellitic acid, pyromellitic acid, tetrahydrophthalic acid, hexahydrophthalic acid, 1 ,2-cyclohexanedicarboxlic acid, 1,3- cyclohexane-discarboxlic acid, 1 ,4-cyclohexane-dicarboxlic acid, 4- methylhexahydrophthalic acid, endomethylenetetrahydropthalic acid, tricyclodecane- dicarboxlic acid, endoethylenehexahydropthalic acid, camphoric acid, cyclohexanetetracarboxlic acid, and cyclobutanetetracarboxylic acid. The cycloaliphatic polycarboxylic acids may be employed either in their cis or in their trans form or as a mixture of the two forms. Esterifiable derivatives of these polycarboxylic acids include their single or multiple esters with aliphatic alcohols having 1 to 4 carbon atoms or hydroxy alcohols having up to 4 carbon atoms, preferably the methyl and ethyl ester, as well as the anhydrides of these polycarboxylic acids, where they exist. Nonlimiting examples of suitable monocarboxylic acids that can be used together with the polycarboxylic acids include benzoic acid, tert-butylbenzoic acid, lauric acid, isonoanoic acid and fatty acids of naturally occurring oils. Nonlimiting examples of suitable polyols include any of those already mentioned above, such as ethylene glycol, butylene glycol, neopentyl glycol, propanediols, butanediols, hexanediols, diethylene glycol, cyclohexanediol, cyclohexanedimethanol, trimethylpentanediol, ethylbutylpropanediol ditrimethylolpropane, trimethylolethane, trimethylolpropane, glycerol, pentaerythritol, dipentaerythritol, tris-hydroxyethyl isocyanate, polyethylene glycol, polypropylene glycol, and polyols derived from natural oils. Nonlimiting examples of monoalcohols that may be used together with the polyols include butanol, octanol, lauryl alcohol, and ethoxylated and propoxylated phenols. Nonlimiting examples of suitable modifying components include compounds which contain a group which is reactive with respect to the functional groups of the polyester, including polyisocyanates and/or diepoxide compounds, and also if desired, monoisocyanates and/or monoepoxide compounds. The polyester polymerization may be carried out by known standard methods. This reaction is conventionally carried out at temperatures of between 180 °C and 280 °C, in the presence if desired of an appropriate esterification catalyst. Typical catalysts for the esterification polymerization are protonic acids, Lewis acids, titanium alkoxides, and dialkyltin oxides, for example lithium octanoate, dibutyltin oxide, dibutyltin dilaurate, para-toluenesulfonic acid under reflux with small quantities of a suitable solvent as entraining agent such as an aromatic hydrocarbon, for example xylene, or a (cyclo)aliphatic hydrocarbon, for example cyclohexane.

[0083] Polyurethanes having hydroxyl functional groups may also be used in the coating compositions along with the hypcrbranched poiyoi. Examples of suitable polyurethane polyols include polyester-polyurethanes, polyether-polyurethanes, and polycarbonate -polyurethanes, including, without limitation, polyurethanes polymerized using as polymeric diol reactants polyethers and polyesters including polycaprolactone polyesters or polycarbonate diols. These polymeric diol-based polyurethanes are prepared by reaction of the polymeric diol (polyester diol, polyether diol, polycaprolactone diol, polytetrahydrofuran diol, or polycarbonate diol), one or more polyisocyanates, and, optionally, one or more chain extension compounds. Chain extension compounds, as the term is being used, are compounds having two or more functional groups, preferably two functional groups, reactive with isocyanate groups, such as the diols, amino alcohols, and diamines. Preferably the polymeric diol-based polyurethane is substantially linear (i.e., substantially all of the reactants are difunctional).

[0084] Diisocyanates used in making the polyurethane polyols may be aromatic, aliphatic, or cycloaliphatic. Useful diisocyanate compounds include, without limitation, isophorone diisocyanate (IPDI), methylene bis-4-cyclohexyl isocyanate (H12MDI), cyclohexyl diisocyanate (CHDI), m-tetramethyl xylene diisocyanate (m-TMXDI), p- tetramethyl xylene diisocyanate (p-TMXDI), 4,4 '-methylene diphenyl diisocyanate (MDI, also known as 4,4'-diphenylmethane diisocyanate), 2,4- or 2,6-toluene diisocyanate (TDI), ethylene diisocyanate, 1,2-diisocyanatopropane, 1,3-diisocyanatopropane, 1,6- diisocyanatohexane (hexamethylene diisocyanate or HDI), 1,4-butylene diisocyanate, lysine diisocyanate, meta-xylylenediioscyanate and para-xylylenediisocyanate, 4-chloro- 1,3-phenylene diisocyanate, 1,5-tetrahydro-naphthalene diisocyanate, 4,4'-dibenzyl diisocyanate, and xylylene diisocyanate (XDI), and combinations of these. Nonlimiting examples of higher-functionality polyisocyanates that may be used in limited amounts to produce branched thermoplastic polyurethanes (optionally along with monofunctional alcohols or monofunctional isocyanates) include 1,2,4-benzene triisocyanate, 1,3,6- hexamethylene triisocyanate, 1,6,11-undecane triisocyanate, bicycloheptane triisocyanate, triphenylmethane-4,4',4"-triisocyanate, isocyanurates of diisocyanates, biurets of diisocyanates, allophanates of diisocyanates, and the like.

[0085] In various embodiments, the polymeric diol preferably has a weight average molecular weight of at least about 500, more preferably at least about 1000, and even more preferably at least about 1800 and a weight average molecular weight of up to about 10,000, but polymeric diols having weight average molecular weights of up to about 5000, especially up to about 4000, may also be preferred. The polymeric diol advantageously has a weight average molecular weight in the range from about 500 to about 10,000, preferably from about 1000 to about 5000, and more preferably from about 1500 to about 4000. The weight average molecular weights may be determined by ASTM D-4274.

[0086] The reaction of the polyisocyanate, polymeric diol, and diol or other chain extension agent is typically carried out at an elevated temperature in the presence of a suitable catalyst, for example tertiary amines, zinc salts, and manganese salts. The ratio of polymeric diol, such as polyester diol, to extender can be varied within a relatively wide range depending largely on the desired hardness or flexibility of the final polyurethane elastomer. For example, the equivalent proportion of polyester diol to extender may be within the range of 1 :0 to 1 :12 and, more preferably, from 1 : 1 to 1 :8. Preferably, the diisocyanate(s) employed are proportioned such that the overall ratio of equivalents of isocyanate to equivalents of active hydrogen containing materials is within the range of 1 : 1 to 1 :1.05, and more preferably, 1 : 1 to 1 : 1.02. The polymeric diol segments typically are from about 35% to about 65% by weight of the polyurethane polymer, and preferably from about 35%) to about 50%> by weight of the polyurethane polymer.

[0087] A polysiloxane polyol may be made by hydrosilylating a polysiloxane containing silicon hydrides with an alkyenyl polyoxyalkylene alcohol containing two or three terminal primary hydroxyl groups, for example allylic polyoxyalkylene alcohols such as trimethylolpropane monoallyl ether and pentaerythritol monoallyl ether.

[0088] Any of the polyol resins and polymers described above may be derivatized to have carbamate groups according to known methods, for example by reaction of a hydroxyl-functional material with an alkyl carbamate, for example methyl carbamate or butyl carbamate, through what is referred to as "transcarbamation" or "transcarbamoylation." In other methods of forming carbamate-functional resins and polymers for use in the coating compositions, the resin and polymers may be polymerized using a carbamate-functional monomer.

[0089] The coating composition containing the hyperb ranched polyol and optional further active hydrogen-functional, resin or polymer also includes at least one cross! inker or curing agent reactive with hydroxyl groups, such as aminoplast crosslinkers having active methylol, methylalkoxy or butylalkoxy groups; polyisocyanate crosslinkers, which may have blocked or unblocked isocyanate groups; polyanhydrides; and polyepoxide functional crosslinkers or curing agents, which could be reactive with the hydroxyls as well as with carboxylic acid groups the hyperbranched polyols.

[0090] Aminoplasts, or amino resins, are described in Encyclopedia of Polymer

Science and Technology vol. 1, p. 752-789 (1985), the disclosure of which is hereby incorporated by reference. An aminoplast is obtained by reaction of an activated nitrogen with a lower molecular weight aldehyde, optionally with further reaction with an alcohol (preferably a mono-alcohol with one to four carbon atoms such as methanol, isopropanol, n-butanol, isobutanol, etc.) to form an ether group. Preferred examples of activated nitrogens are activated amines such as melamine, benzoguanamine, cyclohexylcarboguanamine, and acetoguanamine; ureas, including urea itself, thiourea, ethyleneurea, dihydroxyethyleneurea, and guanylurea; glycoluril; amides, such as dicyandiamide; and carbamate-functional compounds having at least one primary carbamate group or at least two secondary carbamate groups. The activated nitrogen is reacted with a lower molecular weight aldehyde. The aldehyde may be selected from formaldehyde, acetaldehyde, crotonaldehyde, benzaldehyde, or other aldehydes used in making aminoplast resins, although formaldehyde and acetaldehyde, especially formaldehyde, are preferred. The activated nitrogen groups are at least partially alkylolated with the aldehyde, and may be fully alkylolated; preferably the activated nitrogen groups are fully alkylolated. The reaction may be catalyzed by an acid, e.g. as taught in U.S. Patent No. 3,082,180, which is incorporated herein by reference.

[0091] The optional alkylol groups formed by the reaction of the activated nitrogen with aldehyde may be partially or fully etherified with one or more mono functional alcohols. Suitable examples of the mono functional alcohols include, without limitation, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert- butyl alcohol, benzyl alcohol, and so on. Monofunctional alcohols having one to four carbon atoms and mixtures of these are preferred. The etherification may be carried out, for example, the processes disclosed in U.S. Patents No. 4,105,708 and 4,293,692 incorporate the disclosures of which incorporated herein by reference. The aminoplast may be at least partially etherified, and in various embodiments the aminoplast is fully etherified. For example, the aminoplast compounds may have a plurality of methylol and/or etherified methylol, butylol, or alkylol groups, which may be present in any combination and along with unsubstituted nitrogen hydrogens. Examples of suitable curing agent compounds include, without limitation, melamine formaldehyde resins, including monomeric or polymeric melamine resins and partially or fully alkylated melamine resins, and urea resins (e.g., methylol ureas such as urea formaldehyde resin, and alkoxy ureas such as butylated urea formaldehyde resin). One nonlimiting example of a fully etherified melamine-formaldehyde resin is hexamethoxymethyl melamine.

[0092] The al kylol groups are capable of self-reaction to form, oiigomeric and polymeric aminoplast crosslinking agents. Useful materials are characterized by a degree of polymerization. For melamine formaldehyde resins, it is preferred to use resins having a number average molecular weight less than about 2000, more preferably less than 1500, and even, more preferably less than 1000.

100931 A coating composition including aminoplast crosslinking agents may further include a strong acid catalyst to enhance the cure reaction. Such, catalysts are well known in the art and include, for example, para-to 1 en esu 1 ton i c acid, dinonyl naphthalene disulfonic acid, dodecy ! ben/.enesu I ton i c acid, phenyl acid phosphate, monobutyl maleate, butyl phosphate, and hydroxy phosphate ester. Strong acid catalysts are often blocked, e.g. with an amine.

[0094] Particularly for refmish coatings, polyisocyanate crosslinkers are commonly used. Examples of suitable polyisocyanate crosslinkers include, without limitation, alkylene polyisocyanates such, as hexamethylene diisocyanate, 2,2,4- and/or 2,4,4-trimeth.ylhexameth.yl.ene diisocyanate, dodecamethylene diisocyanate, 1 ,4- diisocyanatocyclohexane, l-isocyanato-3,3,5-trim.eth.yl.-5-isocyanatom.ethyicycloh.ex ane ( isophorone diisocyanate), 2,4'- and/or 4,4'-diisocyanatodicyclohexylmethane, 3- isocyanato-m.ethyl-3,5,5-trimeth.yl cyc!ohexyl isocyanate, aromatic polyisocyanates such as 2,4'- and/or 4,4'-diisocyanatodiphenylmethane, 2,4- and/or 2,6-diisocyanatotoluene, naphthylene diisocyanate, and mixtures of these polyisocyanates. Generally, polyisocyanates having three or more isocyanate groups are used; these may be derivatives or adducts of diisocyanates. Useful polyisocyanates may be obtained by reaction of an excess amount of an isocyanate with water, a polyol. (for example, ethylene glycol, propylene glycol, 1 ,3-butylene glycol, neopentyl glycol, 2.2,4-trimeth yl- 1 ,3-pentane diol, hexamethylene glycol, cyclohexane dimethanol, hydrogenated bisphenol A, trimethyiolpropane, trimethylolethane, 1 ,2,6-hexanetri.oi, glycerine, sorbitol or pentaerythritol), or by the reaction of the isocyanate with itself to give an isocyanurate. Examples include biuret-group-containing polyisocyanates, such, as those described, for example, in U.S. Pat. No. 3,124,605 and U.S. Pat. No. 3,201 ,372 or DE-OS 1 ,101 ,394; i socyan u rate-group-con ta i n i n g polyisocyanates, such as those described, for example, in U.S. Pat. No. 3,001 ,973, DE-PS 1 ,022,789, 1 ,222,067 and 1 ,027,394 and in DE-OS 1 ,929,034 and 2,004,048; urethane-group-containing polyisocyanates, such as those described, for example, in DE-OS 953,012, BE-PS 752,261 or U.S. Pat. Nos. 3,394, 164 and 3,644,457; carbodiimide group-containing polyisocyanates, such as those described in DE-PS 1 ,092,007, U.S. Pat. No. 3,152, 162 and DE-OS 2,504,400, 2,537,685 and 2,552,350; allophanate group -containing polyisocyanates, such as those described, for example, in GB-PS 994,890, BE-PS 761 ,626 and NL-OS 7, 102,524; and uretdione group- containing polyisocyanates, such as those described in EP-A 0,377, 177, each reference being incorporated herein by reference.

[0095] Such isocyanate crosslinkers for refmish coating compositions are commonly stored separately and combined with the hydroxyl-functional film-forming components shortly before application. For example, a two-part or two-pack or ivvo- component refmish coating composition may include in a crosslinking part, package, or component one of aliphatic biurets and isocyanurates, such as the isocyanurates of hexamethylene diisocyanate and isophorone di isocyanate.

[0096] Curing catalysts for the urethane reaction such as tin catalysts can be used in the coating composition. Typical examples are without limitation, tin and bismuth compounds including dibutyltin dilaurate, dibutyltin oxide, and bismuth octoate. When used, catalysts are typically present in amounts of about 0.05 to 2 percent by weight tin based on weight of total nonvolatile vehicle.

[0097] A dianhydride may also be used to crosslink the hyperbranched polyol.

Nonlimiting examples of di-cyclic carboxylic anhydrides include pyromellitic dianhydride, ethylenediaminetetraacetic dianhydride, cyclobutane-l ,2,3,4-tetracarboxylic dianhydride, 3 , 3 ',4 ,4 '-biphenyltetracarboxylic dianhydride , tetrahydrofurane-2 ,3,4,5 -tetracarboxylic dianhydride, and cyclohexane- 1 ,2.4,5-tetracarbo.xylie acid dianhydride.

[0098] Polyepoxide crosslinking agents include acrylic polymers having epoxide groups, for example copolymers of allyl glycidyl ether, glycidyl acrylate, or glycidyl methacrylate, as well as polyglycidyl esters and ethers of polyol and polycarboxylic acids. [0099] The coating composition made with the hyperbranched polyol may further include solvents, pigments, fillers, or customary additives.

[00100] A solvent may optionally be utilized in the coating compositions. Although the coating composition may be formulated, for example, in the form of a powder, it is often desirable that the composition be in a substantially liquid state, which can be accomplished with the use of a solvent to either dissolve or disperse the hyperbranched polyol, crosslinker, and other film-forming material or materials. In general, depending on the solubility characteristics of the components, the solvent can be any organic solvent and/or water. In one preferred embodiment, the solvent is a polar organic solvent. For example, the solvent may be a polar aliphatic solvent or polar aromatic solvent. Among useful solvents are ketone, ester, acetate, aprotic amide, aprotic sulfoxide, and aprotic amine solvents. Examples of specific useful solvents include ketones, such as acetone, methyl ethyl ketone, methyl amyl ketone, methyl isobutyl ketone, esters such as ethyl acetate, butyl acetate, pentyl acetate, ethyl ethoxypropionate, ethylene glycol butyl ether acetate, propylene glycol monomethyl ether acetate, aliphatic and/or aromatic hydrocarbons such as toluene, xylene, solvent naphtha, and mineral spirits, ethers such as glycol ethers like propylene glycol monomethyl ether, alcohols such as ethanol, propanol, isopropanol, n-butanol, isobutanol, and tert-butanol, nitrogen-containing compounds such as N-methyl pyrrolidone and N-ethyl pyrrolidone, and combinations of these. In example embodiments, the liquid medium is water or a mixture of water with small amounts of organic water-soluble or water-miscible co-solvents. The solvent in the coating composition may be present in an amount of from about 0.01 weight percent to about 99 weight percent, or in an amount of from about 10 weight percent to about 60 weight percent, or in an amount of from about 30 weight percent to about 50 weight percent.

[00101] When the coating compositions are formulated as basecoat topcoats, monocoat topcoats, or primers they contain pigments and fillers, including special effect pigments. Nonlimiting examples of special effect pigments that may be utilized in basecoat and monocoat topcoat coating compositions include metallic, pearlescent, and color- variable effect flake pigments. Metallic (including pearlescent, and color-variable) topcoat colors are produced using one or more special flake pigments. Metallic colors are generally defined as colors having gonioapparent effects. For example, the American Society of Testing Methods (ASTM) document F284 defines metallic as "pertaining to the appearance of a gonioapparent material containing metal flake." Metallic basecoat colors may be produced using metallic flake pigments like aluminum flake pigments, coated aluminum flake pigments, copper flake pigments, zinc flake pigments, stainless steel flake pigments, and bronze flake pigments and/or using pearlescent flake pigments including treated micas like titanium dioxide-coated mica pigments and iron oxide-coated mica pigments to give the coatings a different appearance (degree of reflectance or color) when viewed at different angles. Metal flakes may be cornflake type, lenticular, or circulation-resistant; micas may be natural, synthetic, or aluminum oxide type. Flake pigments do not agglomerate and are not ground under high shear because high shear would break or bend the flakes or their crystalline morphology, diminishing or destroying the gonioapparent effects. The flake pigments are satisfactorily dispersed in a binder component by stirring under low shear. The flake pigment or pigments may be included in the high solids coating composition in an amount of about 0.01 wt.% to about 50 wt.% or about 15 wt.% to about 25 wt.%, in each case based on total binder weight. Nonlimiting examples of commercial flake pigments include PALIOCROME® pigments, available from BASF Corporation.

[00102] Nonlimiting examples of other suitable pigments and fillers that may be utilized in basecoat and monocoat topcoat coating compositions include inorganic pigments such as titanium dioxide, barium sulfate, carbon black, ocher, sienna, umber, hematite, limonite, red iron oxide, transparent red iron oxide, black iron oxide, brown iron oxide, chromium oxide green, strontium chromate, zinc phosphate, silicas such as fumed silica, calcium carbonate, talc, barytes, ferric ammonium ferrocyanide (Prussian blue), and ultramarine, and organic pigments such as metallized and non-metallized azo reds, quinacridone reds and violets, perylene reds, copper phthalocyanine blues and greens, carbazole violet, monoarylide and diarylide yellows, benzimidazolone yellows, tolyl orange, naphthol orange, nanoparticles based on silicon dioxide, aluminum oxide or zirconium oxide, and so on. The pigment or pigments are preferably dispersed in a resin or polymer or with a pigment dispersant, such as binder resins of the kind already described, according to known methods. In general, the pigment and dispersing resin, polymer, or dispersant are brought into contact under a shear high enough to break the pigment agglomerates down to the primary pigment particles and to wet the surface of the pigment particles with the dispersing resin, polymer, or dispersant. The breaking of the agglomerates and wetting of the primary pigment particles are important for pigment stability and color development. Pigments and fillers may be utilized in amounts typically of up to about 60% by weight, based on total weight of the coating composition. The amount of pigment used depends on the nature of the pigment and on the depth of the color and/or the intensity of the effect it is intended to produce, and also by the dispersibility of the pigments in the pigmented coating composition. The pigment content, based in each case on the total weight of the pigmented coating composition, is preferably 0.5% to 50%>, more preferably 1% to 30%, very preferably 2% to 20%, and more particularly 2.5% to 10% by weight.

[00103] Clearcoat coating compositions typically include no pigment, but may include small amount of colorants or fillers that do not unduly affect the transparency or desired clarity of the clearcoat coating layer produced from the composition.

[00104] Additional desired, customary coating additives agents may be included, for example, surfactants, stabilizers, wetting agents, dispersing agents, adhesion promoters, UV absorbers, hindered amine light stabilizers such as HALS compounds, benzotriazoles or oxalanilides; free-radical scavengers; slip additives; defoamers; reactive diluents, of the kind which are common knowledge from the prior art; wetting agents such as siloxanes, fluorine compounds, carboxylic monoesters, phosphoric esters, polyacrylic acids and their copolymers, for example polybutyl acrylate, or polyurethanes; adhesion promoters such as tricyclodecanedimethanol; flow control agents; film-forming assistants such as cellulose derivatives; rheology control additives, such as the additives known from patents WO 94/22968, EP-A-0 276 501, EP-A-0 249 201 or WO 97/12945; crosslinked polymeric microparticles, as disclosed for example in EP-A-0 008 127; inorganic phyllosilicates such as aluminum-magnesium silicates, sodium-magnesium and sodium-magnesium-fluorine- lithium phyllosilicates of the montmorillonite type; silicas such as Aerosils® .; or synthetic polymers containing ionic and/or associative groups such as polyvinyl alcohol, poly(meth)acryl amide, poly(meth)acrylic acid, polyvinylpyrrolidone, styrene-maleic anhydride copolymers or ethylene-maleic anhydride copolymers and their derivatives, or hydrophobically modified ethoxylated urethanes or polyacrylates; flame retardant; and so on. Typical coating compositions include one or a combination of such additives.

[00105] Coating compositions can be coated by any of a number of techniques well known in the art. These include, for example, spray coating, dip coating, roll coating, curtain coating, knife coating, spreading, pouring, dipping, impregnating, trickling or rolling, and the like. For automotive body panels, spray coating is typically used. Preference is given to employing spray application methods, such as compressed-air spraying, airless spraying, high-speed rotation, electrostatic spray application, alone or in conjunction with hot spray application such as hot-air spraying, for example.

[00106] The coating compositions and coating systems of the invention are employed in particular in the technologically and esthetically particularly demanding field of automotive OEM finishing and also of automotive refmish. The coating compositions can be used in both single-stage and multistage coating methods, particularly in methods where a pigmented basecoat or monocoat coating layer is first applied to an uncoated or precoated substrate and afterward another coating layer may optionally be applied when the pigmented film is a basecoat coating. The invention, accordingly, also provides multicoat coating systems comprising at least one pigmented basecoat and may have least one clearcoat disposed thereon, wherein either the clearcoat or the basecoat has been or both have been produced from the coating composition containing the hyperbranched po!yol as disclosed herein. Both the basecoat and the clearcoat coating composition can include the disclosed hyperbranched poiyol.

[00107] The applied coating compositions can be cured after a certain rest time or

"flash" period. The rest time serves, for example, for the leveling and devolatilization of the coating films or for the evaporation of volatile constituents such as solvents. The rest time may be assisted or shortened by the application of elevated temperatures or by a reduced humidity, provided this does not entail any damage or alteration to the coating films, such as premature complete crosslinking, for instance.

[00108] In one or more embodiments, the coating compositions described herein are advantageously cured via radiation. In such cases, the coating compositions may comprise a photoinitiator. In further embodiments, the photoinitiator is selected from the group consisting of diaryl ketone derivatives, benzoin alkyl ethers, alkoxy phenyl ketones, 0- acylated oximinoketones, polycyclic quinones, benzophenones and substituted benzophenones, xanthones, thioxanthones, chlorosulfonyl and chloromethyl polynuclear aromatic compounds, chlorosulfonyl and chloromethyl heterocyclic compounds, chlorosulfonyl and chloromethyl benzophenones and fluorenones, haloalkanes and combinations thereof.

[00109] While the coatings described herein are advantageously cured via radiation, it is also possible to utilize thermal curing. The thermal curing of the coating compositions has no peculiarities in terms of method but instead takes place in accordance with the typical, known methods such as heating in a forced-air oven or irradiation with IR lamps. The thermal cure may also take place in stages. Another preferred curing method is that of curing with near infrared (NIR) radiation. Although various methods of curing may be used, heat curing is preferred. Generally, heat curing is effected by exposing the coated article to elevated temperatures provided primarily by radiative heat sources. After application, the applied coating layer is cured, for example with heat at temperatures from 30 to 200° C, or from 40 to 190° C, or from 50 to 180° C, for a time of 1 min up to 10 h, more preferably 2 min up to 5 h, and in particular 3 min to 3 h, although longer cure times may also be employed at the temperatures employed for automotive refinish, which are preferably between 30 and 90° C. The hyperbranched polyol can be used for both refinish coatings and for original finish coatings that are cured at higher temperatures. A typical method for applying a refinish coating composition includes application and drying with cure at room temperature or at an elevated temperature between 30 and 90° C. OEM coatings are typically cured at higher temperatures, for example from about 110 to about 135 °C. The curing time will vary depending on the particular components used, and physical parameters such as the thickness of the layers, however, typical curing times range from about 15 to about 60 minutes, and preferably about 15-25 minutes for blocked acid catalyzed systems and about 10-20 minutes for unblocked acid catalyzed systems.

[00110] Cured basecoat layers formed may have a thickness of from about 5 to about 75 μιη, depending mainly upon the color desired and the thickness needed to form a continuous layer that will provide the color. Cured clearcoat layers formed typically have thicknesses of from about 30 μιη to about 65 μιη.

[00111] The coating composition can be applied onto many different types of substrates, including metal substrates such as bare steel, phosphated steel, galvanized steel, or aluminum; and non-metallic substrates, such as plastics and composites. The substrate may also be any of these materials having upon it already a layer of another coating, such as a layer of an electrodeposited primer, primer surfacer, and/or basecoat, cured or uncured.

[00112] The substrate may be first primed with an electrodeposition (electrocoat) primer. The electrodeposition composition can be any electrodeposition composition used in automotive vehicle coating operations. Non-limiting examples of electrocoat compositions include electrocoating compositions sold by BASF. Electrodeposition coating baths usually comprise an aqueous dispersion or emulsion including a principal film-forming epoxy resin having ionic stabilization (e.g., salted amine groups) in water or a mixture of water and organic cosolvent. Emulsified with the principal film- forming resin is a crosslinking agent that can react with functional groups on the principal resin under appropriate conditions, such as with the application of heat, and so cure the coating. Suitable examples of crosslinking agents, include, without limitation, blocked polyisocyanates. The electrodeposition coating compositions usually include one or more pigments, catalysts, plasticizers, coalescing aids, antifoaming aids, flow control agents, wetting agents, surfactants, UV absorbers, HALS compounds, antioxidants, and other additives.

[00113] The electrodeposition coating composition is preferably applied to a dry film thickness of 10 to 35 μιη. After application, the coated vehicle body is removed from the bath and rinsed with deionized water. The coating may be cured under appropriate conditions, for example by baking at from about 135° C. to about 190° C. for between about 15 and about 60 minutes.

[00114] Because the coatings of the invention produced from the coating compositions of the invention adhere excellently even to electrocoats, surfacer coats, basecoat systems or typical, known clearcoat systems that have already cured, they are outstandingly suitable not only for use in automotive OEM finishing but also for automotive refmish or for the modular scratchproofmg of automobile bodies that have already been painted.

[00115] Yet another aspect of the invention pertains to the coatings comprising the hyperbranched polymers as described herein and/or coatings produced by the methods described herein. Such coatings are distinct from previously known coatings because of the polymer bridging, which has additional degrees of freedom in the cured state. The coating may be analyzed according to methods known in the art to determine the types of linkages present. There may also be residual photoinitiator decomposition products, which are not present in coatings cured thermally or by methods other than radiation curing.

[00116] Reference throughout this specification to "one embodiment," "certain embodiments," "various embodiments," "one or more embodiments" or "an embodiment" means that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrases such as "in one or more embodiments," "in certain embodiments," "in various embodiments," "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily referring to the same embodiment of the invention. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments.

[00117] The following examples illustrate, but do not in any way limit, the scope of the methods and compositions as described and claimed. All parts are parts by weight unless otherwise noted.

EXAMPLES

[00118] Example 1 - Synthesis of a flexible hyperbranched polyol with a non- extended C ₆ core and utilizing an unsaturated anhydride

[00119] Initial Charge (preparation of the core): The ingredients according to Table

1 below were combined (all weight percents are relative to total formula unless otherwise indicated):

Table 1 : Adipic acid 13.927 wt%

Xylenes 1.515 wt%

[00120] The mixture was heated to 230 °C, removing water as generated, and processed above 200°C for 4 to 5 hours, removing all water and as much xylene as possible. The batch was then cooled to about 30 °C.

[00121] Appending unsaturation to the arms of the core: After the batch was cooled to about 30 °C, the batch was reacted with the ingredients in amounts as shown in Table 2 below:

Table 2:

[00122] The maleic anhydride was loaded, then flushed with Aromatic 100 and heated to 80 °C. The batch was processed at 70 °C following the acid number until the target (about 288 mg KOH/g NV) was reached. The batch was then reduced with solvent

Methyl n-Propyl Ketone (MPK) 12.516 wt% as needed to keep the viscosity low. A chemical schematic of Example 1, along with the product is shown in FIG. 1.

[00123] Example 2 - Synthesis of a flexible hyperbranched polyol with an extended C ₆ core and utilizing an unsaturated epoxide

[00124] Initial Charge (preparation of the core): The ingredients according to Table

3 below were combined:

Table 3 :

[00125] The mixture was heated to 230 °C, removing water as generated, and processed above 200°C for 4 to 5 hours, removing all water and as much xylene as possible. The batch was then cooled to 90 °C.

[00126] Extension of the core, Phase 1 : After the batch was cooled to 90 °C, the batch was reacted with the ingredients in amounts as shown in Table 4 below:

Table 4:

[00127] The HHPA was added and then flushed and reduced with EEP. The batch was heated to 115°C and exotherm observed. Temperature above 149 °C were avoided. After peak, the batch was heated to 136°C, and then cooled to about 90°C.

[00128] Extension of the core, Phase 2: After the batch was cooled to 90 °C, the batch was reacted with the ingredients in amounts as shown in Table 5 below:

Table 5 :

[00129] After peak, heat to 145°C, (avoid temperature above 149°C), and process at

145°C for 90 minutes, then reduce and cool to 100°C.

[00130] The HHPA was added and then flushed with EEP. The batch was heated to

115°C and exotherm observed. After peak, the batch was heated to 145 °C, and processed for 90 minutes. Temperature above 149 °C were avoided. The batch was then reduced and cooled to 100 °C. The batch was reduced with Aromatic 100 in an amount of 20.654 wt%.

[00131] Adding catalyst: Ν,Ν-dimethylethanolamine (DMEOA) was added, and slow air bubbling into batch was begun prior to addition of glycidyl methacrylate (GMA).

[00132] Appending unsaturation to the arms of the core: After the batch was cooled to about 100 °C, the batch was reacted with the ingredients in amounts as shown in Table 6 below:

Table 6:

[00133] The GMA over 60 to 90 minutes. The batch was maintained at 100 to 115

°C. The batch was then flushed with Aromatic 100 and held at 115 °C. The batch was processed at 115 °C following the acid number until stabilized. The WPE [WHAT IS WPE?] was checked. Once the WPE was greater than 18,000, the then the batch was cooled to 60 °C and filled off. A chemical schematic of Example 2, along with the product is shown in FIG. 2.

[00134] Example 3 - Synthesis of a flexible hyperbranched polyol with a non- extended C ₆ core and utilizing an unsaturated anhydride

[00135] Initial Charge (preparation of the core): The ingredients according to Table 7 below were combined:

Table 1 :

[00136] The mixture was heated to 230 °C, removing water as generated, and processed above 200°C for 4 to 5 hours, removing all water and as much xylene as possible. The batch was then cooled to about 70 °C.

[00137] Appending unsaturation to the arms of the core: After the batch was cooled to about 70 °C, the batch was reacted with the ingredients in amounts as shown in Table 8 below:

Table 8:

[00138] The OSA was loaded, then flushed with MPK and processed at 70 °C. The batch was processed at 70 °C following the acid number until the target (about 180 mg KOH/ g NV) was reached. The batch was then reduced with solvent (MPK 0.440 wt%) as needed to keep the viscosity low. A chemical schematic of Example 3, along with the product is shown in FIG. 3.

[00139] Example 4 - Preparation of a Coating Formulation

[00140] The esterification product of about 2 mol TMP with 1 mol adipic acid was extended through the ring opening reaction with about 4 mol maleic anhydride (the polyol of Example 1). A coating formulation was prepared by mixing the ingredients in the amounts shown in Table 9:

Table 9:

Irgacure BP 1.49 photoinitiator

Irgacure TPO-L 0.94 photoinitiator

BYK 3510 0.90 additive

[00141] The resulting coating was then applied to a metal substrate and exposed to actinic radiation and subsequently cured completely to form a hard film coating on the metal.

[00142] Example 5 - Preparation of a Coating Formulation

[00143] The esterification product of about 2 mol TMP with 1 mol adipic acid was extended through the ring opening reaction with about 4 mol octenylsuccinic anhydride (the polyol of Example 3). A coating formulation was prepared by mixing the ingredients in the amounts shown in Table 10:

Table 10:

[00144] The resulting coating formulation containing the example of this invention was then applied to a metal substrate and exposed to actinic radiation and subsequently cured completely to form a hard film coating on the metal.

[00145] Example 6 - Preparation of a Coating Formulation

[00146] About 2 mol of HHP A were reacted onto 1 mol of K-Flex UD 320-100 urethane diol through a ring-opening reaction to form a di-acid urethane polymer onto which about 2 mol of TMP were fused through esterification condensation. The polymer was extended by a second round of ring-opening reactions of about 4 mol HHPA onto the prior esterification product, then further extended by another ring-opening reaction with about 4 mol glycidyl neodecanoate. Then another ring-opening reaction was used to append about 2 mol maleic anhydride onto the polymer to form this urethane-containing polymer. A coating formulation was prepared by mixing the ingredients in the amounts shown in Table 11 :

Table 11 :

[00147] The resulting coating formulation containing the example of this invention was then applied to a metal substrate and exposed to actinic radiation and subsequently cured completely to form a hard film coating with urethane content on the metal.

[00148] Example 7 - Preparation of a Coating Formulation

[00149] About 2 mol of HHPA were reacted onto 1 mol of a proprietary carbamate diol through a ring-opening reaction to form a di-acid carbamate molecule onto which about 2 mol of TMP were fused through esterification condensation. The polymer is extended by a second round of ring-opening reactions of about 4 mol HHPA onto the prior esterification product, then further extended by another ring-opening reaction with about 4 mol glycidyl neodecanoate. Then another ring-opening reaction as used to append about 2 mol maleic anhydride onto the polymer to form this carbamate-containing polymer. A formulation was prepared by mixing the ingredients in the amounts shown in Table

Table 12:

[00150] The resulting coating formulation containing the example of this invention was then applied to a metal substrate and exposed to actinic radiation and subsequently cured completely to form a hard film coating with carbamate content on the metal.

[00151] Example 8 - Preparation of a Coating Formulation

[00152] The esterification product of about 2 mol TMP with 1 mol pripol 1009, (C- 36 di-acid), was extended through the ring opening reaction with about 2 mol maleic anhydride. A coating formulation was prepared by mixing the ingredients in the amounts shown in Table 13:

Table 13:

Irgacure MBF 5.06 photoinitiator

Irgacure BP 1.49 photoinitiator

Irgacure TPO-L 0.94 photoinitiator

BYK 3510 0.90 additive

[00153] The resulting coating formulation containing the example of this invention was then applied to a metal substrate and exposed to actinic radiation and subsequently cured completely to form a hard film coating on the metal.

[00154] Example 9 - Preparation of a Coating Formulation

[00155] The esterification product of about 2 mol pentaerythritol ethoxylate with 1 mol adipic acid was extended through the ring opening reaction with about 3 mol maleic anhydride. A coating formulation was prepared by mixing the ingredients in the amounts shown in Table 14:

Table 14:

[00156] The resulting coating formulation containing the example of this invention was then applied to a metal substrate and exposed to actinic radiation and subsequently cured completely to form a hard film coating on the metal.

[00157] Example 10 - Preparation of a Coating Formulation [00158] The esterification product of about 2 mol pentaerythritol ethoxylate with 1 mol Pripol 1009, (C-36 di-acid), was extended through the ring opening reaction with about 3 mol maleic anhydride. A coating formulation was prepared by mixing the ingredients in the amounts shown in Table 15:

Table 15:

[00159] The resulting coating formulation containing the example of this invention was then applied to a metal substrate and exposed to actinic radiation and subsequently cured completely to form a hard film coating on the metal.

[00160] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the invention, and all such modifications are intended to be included within the scope of the invention.