MXPA01011328A

MXPA01011328A - Curable coating composition with improved stability

Info

Publication number: MXPA01011328A
Application number: MXPA/A/2001/011328A
Authority: MX
Inventors: Ohrbom Walter; Harris Paul
Original assignee: Basf Corporation
Priority date: 1999-10-28
Filing date: 2001-11-07
Publication date: 2002-06-05

Abstract

The present invention provides a curable coating composition that includes at least three components. The coating composition includes a component (a) having at least one carbamate group or urea group and having a lactone or hydroxy carboxylic acid moiety. The second component (b) of the coating composition is the reaction product of a polyol having at least one branch point, i.e., carbon bonded to at least three other carbons, with a lactone or hydroxy carboxylic acid. The third component of the coating composition is a curing agent that is reactive with the first two components. Preparation of coated articles using the compositions of the invention is also disclosed.

Description

CURABLE COATING COMPOSITION WITH IMPROVED STABILITY Field of the Invention This invention relates to curable coating compositions, especially to compositions for high gloss top coatings, particularly for clear coatings of color-plus-clear composite coatings. BACKGROUND OF THE INVENTION [0002] Curable or heat settable coating compositions are widely employed in coating techniques, particularly for top coatings in the automotive and industrial coatings industries. Color-plus-clear composite coatings are particularly useful as top coatings for which exceptional gloss, color depth, image distinction or special metallic effects are desired. The automotive industry has made extensive use of these coatings for automotive body panels. Single-layer top coatings and clear coatings of color-plus-clear composite coatings, however, require an extremely high degree of clarity and gloss to achieve the desired visual effect. These coatings also require a low degree of visual aberrations in the coating surface in order to achieve the desired visual effect such as high image distinction (DOl = Distinctness Of Image). As such, these coatings are especially susceptible to a phenomenon known as environmental etching. Environmental etching manifests as spots or marks on or in the coating finish, which often can not be removed by rubbing. It is often difficult to predict the degree of environmental etch resistance that a high gloss topcoat or light-color composite coating will exhibit. Many coating compositions known for their durability and / or weather resistance when used in exterior paints, such as known high solids enamels, do not provide the desired level of environmental etch resistance when used in high gloss coatings. such as the clear coating of a lighter-colored coating. Curable coating compositions using carbamate or urea functional materials are described, for example, in U.S. Patents. Nos. 5,756,213; 5,760,127, 5,770,650; 5,792,810; and 5,827,930, each of which is incorporated herein by reference.

These patents describe coating compositions that include a functional-urea or functional-carbamate compound, prepared by a ring-opening reaction with a lactone. While these compounds have proven to be useful for coatings, particularly coatings for flexible substrates, it has been found that even a modest number of lactone units in the compounds, results in solidification problems during storage at room temperature and the need to employ higher amounts of solvent than desired in order to obtain convenient viscosities. On the other hand, decreasing the average number of lactone units per compound leads to less properties than the latter in the cured coating such as more poor durability, lower resistance to environmental etching and less resistance to scratches and stains or usual wear. COMPENDIUM OF THE INVENTION The present invention provides a curable coating composition, which includes at least three components: a component (a), a component (b) and one component (c). The present invention also provides a composition comprising the component (a) and component (b) having improved stability against crystallization or solidification, compared to compositions without component (b). Component (a) has at least one carbamate group or urea group and has a lactone or hydroxycarboxylic acid moiety. When used in connection with the invention, the term "carbamate group" refers to a group having a structure wherein R is H or alkyl. Preferably, R is H or alkyl of 1 to about 4 carbon atoms, and more preferably R is H. When used in connection with the invention, the terminal urea group refers to a group having a structure wherein R 'and R "each independently are H or alkyl, or R' and R" together form a heterocyclic ring structure. Preferably R 'and R "each independently are H or alkyl from 1 to about 4 carbon atoms or together form an ethylene bridge and more preferably R' and R" each independently are H. The terminal urea group of the invention it is distinguished from urea linking groups for which R "will be different from alkyl Preferred compounds (a) can be represented by the structures wherein R, R ', and R "are as previously defined, R1 is alkylene or arylalkylene, preferably alkylene, and particularly preferably alkylene with 5 to 10 carbon atoms, Rz is alkylene or arylalkylene, preferably alkylene, and particularly preferably alkylene of about 5 to 10 carbon atoms, R3 is alkylene (including cycloalkylene), alkylarylene, arylene, or a structure including a cyanuric ring, a urethane, a urea group, a carbodiimide group, a biuret structure, or an allophonate group, preferably alkylene (including cycloalkylene), or a structure including a cyanuric ring, - n is from 1 to about 10, preferably from 1 to about 5; m is from 2 to about 6, preferably 2 or 3, and L is O, NH, or NR 4, wherein R 4 is an alkyl, preferably an alkyl of 1 to about 6 carbon atoms The compound (a) can be prepared by a process that involves a step of reacting in a together a lactone or a hydroxycarboxylic acid and a compound comprising a carbamate or urea or. a group that can be converted to a carbamate or urea group and a group that is reactive with lactone or hydroxycarboxylic acid. In the case of a group that can be converted to a carbamate or urea group, the group is converted to the carbamate or urea group either during or after the reaction with the lactone or hydroxycarboxylic acid. The process for preparing compound (a) may include an additional step wherein a hydroxyl functional product of the first step is reacted with a compound having at least two isocyanate groups. The second component (b) is a branched polyol having a lactone or hydroxycarboxylic acid moiety. The branched polyol has at least two hydroxyl groups and at least one branch point. By "branching point" is meant a carbon atom having carbon-carbon bonds with at least three other carbon atoms. Preferred compounds of the second component (b) can be represented by the structure wherein R1, n, and m are as previously defined, R5 is an m-valent portion having at least one branch point and X is a portion having an active hydrogen group. Preferably, R 5 is alkylene, more preferably with a branch point and particularly preferably R 5 has from 2 to about 12 carbon atoms. Preferably, X is OH or X is a portion having a terminal urea or carbamate group, more preferably X is OH. The third component (c) of the coating composition is a curing oil that is reactive with the first two components. Additionally, the invention provides a process for increasing the solids content of a coating composition that includes a component (a) as described above, having at least one urea group or carbamate group and having a lactone or hydroxycarboxylic acid moiety. In the process of the invention, a small amount of a polyol (b) (1) having at least one branch point, preferably about 0.2 to about 10% based on the total weight of the components (a) and ( b), is incorporated into the composition, preferably during a step wherein a compound (a) (1) is reacted with a lactone or hydroxycarboxylic acid to form component (a). Preferred polyols (b) (1) can be represented by the structure R5 (0H) m, wherein R5 and m are as previously defined. The invention further provides an article having a substrate, in particular a flexible substrate, on which substrate is a cured coating derived from a coating composition according to the invention and a method for producing this coating on a substrate. DETAILED DESCRIPTION The composition according to the present invention includes as a first component, a compound (a) having at least one terminal urea group or carbamate group and having a lactone or hydroxy acid moiety. By "lactone or hydroxy acid portion" is meant a structure that results from incorporating a lactone or hydroxy acid into the compound. For example, a lactone or hydroxy acid can be incorporated into the compound (a) with an ester or polyester segment by reaction with a primary or secondary hydroxyl or amine group or in a precursor to the compound (a). Preferred compounds (a) can be represented by structures - -NHR " wherein R, R ', and R "are as previously defined, R1 is alkylene or arylalkylene, preferably alkylene, and particularly preferably alkylene with 5 to 10 carbon atoms, R2 is alkylene or arylalkylene, preferably alkylene, and particularly preferably alkylene of about 5 to about 10 carbon atoms: R3 is alkylene (including cycloalkylene), alkylarylene, arylene, or a structure including a cyanuric ring, a urethane group, a urea group, a carbodiimide group, a biuret structure, or an allophonate structure, preferably alkylene (including cycloalkylene), or a structure including a cyanuric ring, n is from 1 to about 10, preferably from 1 to about 5; m is from 2 to about 6, preferably 2 or 3, and L is O, NH, or NR 4, wherein R 4 is an alkyl, preferably alkyl of 1 to about 6 carbon atoms Compound (a) can be prepared by a process that involves an of reacting together a lactone or a hydroxycarboxylic acid and a compound (a) (1), comprising a terminal carbamate or urea group or a group that can be converted to a terminal carbamate or urea group and a group that is reactive with the lactone or hydroxycarboxylic acid. Preferably the compound (a) (1) has a terminal carbamate or urea group, or in a preferred embodiment, has a carbamate group or a group that can be converted to a carbamate group. In a particularly preferred embodiment, the compound (a) (1) has a carbamate group. Suitable functional groups reactive with the lactone or hydroxylcarboxylic acid include without limitation, hydroxyl groups, carboxyl groups, isocyanate groups and primary and secondary amine groups. Preferably, the compound (a) (1) has a hydroxyl group or an amine group such as the group reactive with the lactone or hydroxylcarboxylic acid. Compound (a) (1) has at least one group that is reactive with lactone or hydroxycarboxylic acid and preferably has from one to about three of these groups, and more preferably has one of these reactive groups. In a preferred embodiment, the compound (a) (1) has a carbamate group and a hydroxyl group. A preferred example of this compound is hydroxyalkyl carbamate, particularly a β-hydroxyalkyl carbamate. In another preferred embodiment, the compound (a) (1) has a terminal urea group and a hydroxyl group. Suitable compounds (a) (1) include, without limitation, any of these compounds having a terminal carbamate or urea group and a lactone reactive group or hydroxylcarboxylic acid which are known in the art. Hydroxy propyl carbamate and hydroxy ethylene urea, for example are well known and commercially available. Amino carbamates are described in U.S. Pat. No. 2,842,523. Hydroxy urea can also be prepared by reacting the amine group of an amino alcohol with hydrochloric acid and then urea to form a hydroxyurea compound. An amino alcohol can be prepared, for example by reacting an oxazolidone with ammonia. Amino ureas can be prepared for example by reacting a ketone with a diamine having a protected amine group of reaction (for example by steric hindrance), followed by reaction with HNCO (for example as generated by thermal decomposition of urea) and finally reaction with Water. Alternatively, these compounds can be prepared starting from a compound having a group that can be converted to carbamate or terminal urea, these groups are described below and converting this group to carbamate or urea, before starting the reaction with the lactone or acid hydroxy carboxylic In a particularly preferred embodiment the compound (a) (is prepared by a process involving a step of reacting together a lactone or hydroxycarboxylic acid and the compound (a) (1) in the presence of a minor amount of a compound (b) ) (1) Compound (b) (1) is a polyol that can be represented by the structure R5 (0H) m, where R5, n and m are as previously defined. The compound (b) is included in an amount that is sufficient to stabilize the composition including components (a) and (b) for a period of time of at least about 6 months. In particular, compound (b) is included in an amount that is sufficient to prevent solidification at about 20 ° C of component (a) for at least about 6 months. Component (b) is included in an amount sufficient to keep component (a) included for at least about 6 months. If, during the period of at least 6 months the mixture including the components (a) and (b) is cooled to a temperature below about 0 ° C at whose temperature the mixture solidifies, then when heated again to about 20 ° C. ° C, the mixture should be liquefied again. In another aspect of the invention, the preparation (a) includes an additional step wherein the product of the reaction of the compound (a) (1) is reacted with the lactone or carboxylic acid with a polyisocyanate. Preferably, the product of the compound (a) (1) and the lactone or hydroxycarboxylic acid has a hydroxyl group at the end of the lactone or the hydroxycarboxylic acid segment which is reacted with the polyisocyanate. Suitable examples of polyisocyanate compounds include both aliphatic polyisocyanates and aromatic polyisocyanates. Useful polyisocyanates include monomeric isocyanates, for example aliphatic diisocyanates such as ethylene disocyanate and diisocyanate propane, 1,3-diisocyanatopropane, 1,6-diisocyanatohexane (hexamethylene diisocyanate or HMDI), 1,4-butylene diisocyanate, lysine diisocyanate, 1,4- methylene bis- (cyclohexyl isocyanate) and diisocyanate isophorone (IPDI), and aromatic diisocyanates and arylaliphatic diisocyanates such as the various isomers of toluene diisocyanate, meta-xylylenediacyanate and para-xylylenediisocyanate, 4-chloro-1,3-phenylene diisocyanate, , 5-tetrahydro-naphthalene diisocyanate. 4, 4 '-dibenzyl diisocyanate, and 1, 2,4-benzene triisocyanate. In addition, the various isomers of, Cf, ',', -tetramethyl xylylene diisocyanate can be used. Functional isocyanate oligomers or low molecular weight reaction products of the monomeric isocyanates which may have from about 6 isocyanate groups may also be employed. Examples of these include isocyanurates and the reaction products of excess isocyanate with polyols such as the product of 3 moles of diisocyanate with one mole of 1 triol (for example 3 moles of IPDI with one mole of trimethylolpropane or two moles of IPDI with one neopentyl glycol mol); reaction products of isocyanate with urea (biurets); and reaction products of isocyanate with urethane (allophanates). The polyisocyanate preferably has two to four isocyanate groups and more preferably the polyisocyanate has 2 or 3 isocyanate groups per molecule. Isocyanurates such as isocyanurates of isophorone diisocyanate or hexamethylene diisocyanates are particularly preferred. In a particularly preferred embodiment, a β-hydroxyalkyl carbamate is reacted with epsilon-caprolactone and the reaction product is then reacted with a polyisocyanate, preferably the isocyanurate of IPDI. It will be appreciated that the order of the various reaction steps in many cases can be varied in the synthesis of the compounds of the invention. When a compound (a) (1) having a group that can be converted to carbamate or terminal urea is used, the conversion of the group to carbamate or urea can be achieved during or after the reaction with the lactone or the hydroxycarboxylic acid, to produce the first component. Groups which can be converted to carbamate include cyclic carbonate groups, epoxy groups and unsaturated bonds. Cyclic carbonate groups can be converted to carbamate groups with reaction with ammonia or a primary amine, which opens the ring of the cyclic carbonate to form a β-hydroxy carbamate. Epoxy groups can be converted to carbamate groups by first converting to a cyclic carbonate group by reaction with C02. This can be done at any pressure, from atmospheric to super-critical C02 pressures, but preferably under high pressure, for example 4.92 to 10.55 kg / cm2 (70 to 150 psi). The temperature for this reaction is preferably 60-150 ° C. Useful catalysts include any which exhibits an oxirane ring such as tertiary amine or quaternary salts (eg tetramethyl ammonium bromide), combinations of complex organotin halides and alkyl phosphonium halides (eg (CH3) 3SnI, Bu4SnI, Bu4PI, and ( CH3) 4PI), potassium salts (for example K2C03, K1), preferably in combination with crown ethers, tin octoate, calcium octoate and the like. The cyclic carbonate group can then be converted to a carbamate group as described above. Any unsaturated bond can be converted to a carbamate group by reacting first with peroxide to convert to an epoxy group, then with C02 to form a cyclic carbonate, and then with ammonia or with a primary amine to form the carbamate. Other groups, such as hydroxyl groups or isocyanate groups can also be converted to carbamate groups. However, if these groups were present in compound (a) (1) and it is desired to convert those groups to carbonate after reaction with the lactone or hydroxycarboxylic acid, they should be blocked or protected in such a way that they do not react during the lactone reaction. When blocking these groups is not possible, the conversion to carbamate or terminal urea would have to be completed before the lactone reaction. Hydroxyl groups can be converted to carbonate groups by reaction with a monoisocyanate (for example methyl isocyanate) to form a secondary carbamate group (that is, a carbamate of the above structure wherein R is alkyl) or with cyanic acid (which can be formed in in situ by thermal decomposition of urea) to form a primary carbamate group (ie, R in the previous formula is H). This reaction preferably occurs in the presence of a catalyst as is known in the art. A hydroxyl group can also be reacted with phosgene and then ammonia to form a primary carbamate group or by reaction with the hydroxyl with phosgene and then a primary amine to form a compound having secondary carbamate groups. Another approach is to react an isocyanate with a compound such as hydroxyalkyl carbamate to form an isocyanate derivative end-terminated with carbamate. For example, an isocyanate group in toluene diisocyanate can be reacted with hydroxypropyl carbamate, followed by reaction of the other isocyanate group with an excess of polyol, to form a hydroxy carbamate. Finally, carbamates can be prepared by a transesterification approach wherein a hydroxyl group is reacted with an alkyl carbamate (eg, methyl carbamate, ethyl carbamate, butyl carbamate) to form a compound containing the primary carbamate group. This reaction is carried out at elevated temperatures, preferably in the presence of a catalyst such as a metal organ catalyst (for example dibutyltin dilaurate). Other techniques for preparing carbamates are also known in the art and are described for example in P. Adams and F. Baron, "Esters of Carbamic Acid", Chemical Review, v. 65, 1965 and in the U.S. patent. No. 5,474,811, granted to Rehfuss and St. Aubin. Groups such as oxazolidone can also be converted to terminal urea after reaction with the lactone or the hydroxycarboxylic acid. For example, hydroxyethyl oxazolidone can be used to react with the lactone or hydroxycarboxylic acid, followed by reaction of ammonia or a primary amine with the oxazolidone to generate the urea functional group. A preferred class of compounds (a) (1) having a reactive group with the lactone or the hydroxycarboxylic acid and a group that can be converted to the carbamate are the hydroxyalkyl cyclic carbonates. Hydroxyalkyl cyclic carbonates can be prepared by a number of approaches. Certain hydroxyalkyl cyclic carbonates such as 3-hydroxypropyl (ie, glycerin carbonate) are commercially available. Cyclic carbonate compounds can be synthesized by any of several different approaches. One approach involves reacting a compound containing the epoxy group with C02 under conditions and with catalysts as previously described. Epoxides can also be reacted with ß-bu irolactone in the presence of these catalysts. In another approach, a glycol such as glycerin is reacted at temperatures of at least 80 ° C with diethyl carbonate in the presence of a catalyst (for example potassium carbonate) to form a hydroxyalkyl carbonate. Alternatively, a functional compound containing a 1,2-diol ketal having the structure: a ring can be opened with water, preferably with trace amounts of acid, to form a 1,2-glycol, the glycol is then further reacted with diethyl carbonate to form the cyclic carbonate. Cyclic carbonates typically have rings of 5 to 6 members as is known in the art. Rings of 5 members are preferred due to their ease of synthesis and greater degree of commercial availability. 6-membered rings can be synthesized by reacting phosgene with 1,3-propanediol, under conditions known in the art for the formation of cyclic carbonates. Preferred cyclic hydroxyalkyl carbonates used in the practice of the invention can be represented by the formula: (R > " wherein R (or each instance of R if n is more than 1) is a hydroxyalkyl group of 1 to 18 carbon atoms, preferably 1 to 6 carbon atoms, and more preferably 1 to 3 carbon atoms, which may be linear or branched and may have substituents in addition to the hydroxyl group and n is 1 or 2, which may be substituted by one or more other substituents such as blocked amines or unsaturated groups. The hydroxyl group may be on a secondary or tertiary primary carbon. More preferably, R is - (CH 2) p-0H, wherein the hydroxyl may be on a primary or secondary carbon and p is 1 to 8, and even more preferable where the hydroxyl is on a primary carbon and p is 1 or 2. The compound (a) (2) can be a lactone or a hydroxy carboxylic acid. Lactones which can be ring-opened by an active hydrogen are well known in the art. They include for example e-caprolactone, α-caprolactone, β-butyrolactone, β-propriolactone, β-butyrolactone, α-preyl-butyl-butyrolactone, β-methyl-β-butyrolactone, α-valerolactone, d-valerolactone, lactone ? -nonanoica, lactone and -octanoica, and pentolactone. In a preferred embodiment, the lactone is e-caprolactone. Lactones useful in the practice of the invention can also be characterized by the formula: wherein n is a positive integer from 1 to 7 and R is one or more H atoms, or substituted or unsubstituted alkyl groups of 1 to 7 carbon atoms. The lactone ring opening reaction is typically conducted at elevated temperature (eg, 80-150 ° C). The reagents are usually liquid, so that a solvent is not necessary, however, a solvent may be useful to promote good conditions for the reaction, even if the reagents are liquid. Any non-reactive solvent can be used, including both polar and non-polar organic solvents. Examples of useful solvents include toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, and the like. A catalyst of preference is present. Useful catalysts include protonic acids (e.g., octanoic acid, • AmberlystMR 15 (Rohm &Haas)), and tin catalysts (for example, stannous octoate). Alternatively, the reaction can be initiated by forming a sodium salt of the hydroxyl group in the molecules that react, which will react with the lactone ring. A hydroxy carboxylic acid can also be used with the compound (a) (2). Hydroxycarboxylic acids include dimethylhydroxypropionic acid, hydroxy stearic acid, tartaric acid, lactic acid, 2-hydroxy-1-benzoic acid and N- (2-hydroxyethyl) ethylene diamine triacetic acid. The reaction can be carried out under typical esterification conditions, for example at temperatures from room temperature to about 150 ° C, and with catalysts such as calcium octoate, metal hydroxides such as potassium hydroxide, Group I or Group II metals such as sodium or lithium, metal carbonates such as potassium carbonate or magnesium carbonate (which can be improved by use in combination with crown ethers), organ metal oxides and esters such as dibutyl tin oxide, stannous octoate and calcium octoate, alkoxides of metal such as sodium methoxide and aluminum tripidoxide, protic acids such as sulfuric acid or Ph4SbI. The reaction can also be conducted at room temperature with a polymer supported catalyst such as Amberlyst-15MR (available from Rohm &Haas) as described by R. Anand in Synthetic Communications, 24 (19), 2743-47 (1994), the description of which is incorporated herein by reference. The reaction can be carried out with an excess of the compound having the group reactive with hydroxy carboxylic acid. The reaction with the compound (a) (2) can provide chain extension of the compound (a) (1) molecule if sufficient quantities of the compound (a) (2) are present. The relative amounts of the compound (a) (1) and the lactone and / or hydroxy acid (a) (2) can be varied to control the degree of chain extension.

The reaction of the lactone ring or hydroxy carboxylic acid with a hydroxyl group or amine results in the formation of an ester or amide and an OH group. The resulting OH group can then react with another available lactone ring or hydroxy carboxylic acid molecule, thereby resulting in chain extension. The reaction in this manner is controlled by the ratio of the compound (s) (a) (2) to the amount of initiator compound (a) (1). In the preferred embodiments of the present invention, the ratio of equivalents of lactone and / or hydroxy carboxylic acid to equivalents of active hydrogen groups in compound (a) (1), is preferably from 0.1: 1 to 10: 1, and more preferably from 1: 1 to 5: 1. When the reaction product has an acid group, the acid group can then be converted to a hydroxyl group by well-known techniques such as reaction with ethylene oxide. The coating composition further includes a component (b). Component (b) can be prepared according to the process set forth above, wherein compound (a) (1) is a polyol (b) (1) reacts simultaneously with the lactone or the hydroxy carboxylic acid compound (a) ( 2) . Alternatively, the components (a) and (b) can be formed separately and combined in the coating composition. The compound (b) can be prepared by a process that includes a step of reacting together a compound (b) (2) which is a lactone or a hydroxy carboxylic acid, with a compound (b) (1). E compound (b) (1) is a polyol having at least one branch point. Examples of suitable lactones and hydroxy carboxylic acids include those already mentioned above. Examples of suitable polyols such as compound (b) (1) include without limitation neopentyl glycol, 2-ethyl-l, 3-hexanediol, 2,5-dimethyl-2,5-hexanediol, 2,2,4-trimethyl-1 , 3-pentanediol, 2, 2-diethyl-l, 3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2,4-dimethyl-2,4-pentanediol, 3,3-dimethyl-1 , 2-butanediol, l-ethyl-2-propyl-1,5-pentanediol, 2-ethyl-2-methyl-l, 3-propanediol, 2-methyl-2,4-pentanediol, 1, 2-c iclohexandimet anol , 1,4-cyclohexanedimethanol, and also particularly preferred are 2-ethyl-l, 3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-2-methyl-l, 3-propanediol, and l-ethyl-2-propyl-1,5-pentanediol. The amount of neopentyl polyol, glycol, 2-ethyl-1,3-hexanediol, 2,5-dimethyl-2,5-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2,2-diethyl- l, 3-propanediol, 2-methyl-2-propyl-l, 3-propanediol, 2,4-dimethyl-2,4-pentanediol, 3, 3-dimethyl-l, 2-butanediol, l-ethyl-2- propyl-1, 5-pentanediol, 2-ethyl-2-methyl-l, 3-propanediol, 2-methyl-2,4-pentanediol, 1,2-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, and also particularly preferred are 2 -ethyl-l, 3-hexanediol, 2, 2, 4-trimethyl-1,3-pentanediol, 2-ethyl-2-methyl-l, 3-propanediol, and l-ethyl-2-propyl-1, 5- pentandiol. Having at least one branch point preferably is from about 0.2 to about 10% by weight based on the weight of components (a) and (b). Component (b) preferably has a structure wherein R1, n, and m are as defined above, R5 is a m-valent portion having at least one branch point and X is a portion having an active hydrogen group. Preferably, R 5 is alkylene or substituted alkylene, more preferably with a branching point and preferably R 5 has from 2 to about 12 carbon atoms.X is OH or X is a portion having a terminal carbamate or urea group, more preferably X is OH. The compound (b) (1) can be represented by the structure R5- (0H) m, wherein R5 and m is as previously defined. In a preferred embodiment, component (b) has a structure as illustrated above where X is OH. In other cases, it may be advantageous to modify the hydroxyl functional compound as described in U.S. Pat. No. 5,827,930, the entire description of which is incorporated herein by reference, to provide a component (b) having a terminal carbamate or urea functionality as defined above. The hydroxyl group resulting from the reaction of the compound (b) (1) with the compound (b) (2) lactone or hydroxy carboxylic acid can be reacted with a compound (b) (3) to provide a terminal carbamate or urea functionality. Compound (b) (3) has a group that is reactive with the hydroxyl group of the reaction product of (b) (1) with (b) (2) to provide a group that will be reactive with the crosslinking compound (c) ), preferably a carbamate or urea group or group that can be converted to carbamate or urea. A number of compounds can be used as the compound (b) (3), to convert a hydroxyl group in the product of (b) (1) and (b) (2) to a carbamate group. The hydroxyl groups can be converted to carbamate groups by reaction with a monoisocyanate such as methyl isocyanate or with cyanic acid (which can be formed by thermal decomposition of urea) to form a primary carbamate group. A catalyst can be used. A hydroxyl group can also be reacted with phosgene and then ammonia to form a compound having primary carbamate functionality (R is hydrogen) or with phosgene and then a primary amine to form a compound having secondary carbamate functionality (R is alkyl).

In another method, alkyl carbamate such as methyl carbonamate or butyl carbamate or substituted alkyl carbamate such as hydroxy propyl carbamate, can be transesterified with the hydroxyl group. This reaction is carried out with heating and preferably in the presence of a catalyst such as a metallic organ catalyst such as dibutyltin dilaurate. Additionally, a methylol acrylamide compound can be reacted with the hydroxyl group and then converted to carbamate by reaction of the unsaturated acrylamide bond with peroxide, then C02, then ammonia or a primary amine. It is also possible to react the hydroxyl with a partially blocked disocyanate, then release the isocyanate and react the isocyanate group regenerated with a hydroxyalkyl carbamate or hydroxy urea (ie hydroxypropyl carbamate or hydroxyethyl ethylene urea). A diisocyanate in which the isocyanate groups have different reactivities, such as toluene diisocyanate, is particularly suitable for semi-blocking. Similarly, the semi-blocked polyisocyanate can be reacted first with the carbamate or hydroxy-functional urea compound and then deblocked and reacted with the hydroxy functional product of (b) (1) and (b) (2).

The coating composition further includes a component (c) which is a curing agent or curing agents reactive with components (a) and (b). Each curing agent should be reactive with the functionality in one or both of components (a) and (b). For example, the curing agent (s) of component (c) can be reactive with carbamate groups, urea groups and / or hydroxyl groups, depending on the functionalities of components (a) and (b). Useful curing agents include materials having active methylol and methyl alkoxy groups, such as amino-plating interlacing agents, or phenol / formaldehyde adducts; curing agents having isocyanate groups, particularly blocked isocyanate curing agents, curing agents having epoxide groups, amine groups, acid groups, siloxane groups, cyclic carbonate groups and anhydride groups; and its mixtures. Examples of preferred curing agent compounds include, without limitation, melamine formaldehyde resin (including monomeric or polymeric melamine resin and partially or completely alkylated melamine resin), blocked or unblocked polyisocyanates (eg, TDI, MDI, isophorone diisocyanate, hexamethylene diisocyanate, and isocyanurates). the same, which may be blocked for example with alcohols or oximes), urea resins (for example methylol ureas such as urea formaldehyde resin, alkoxy ureas such as butylated formaldehyde urea resin, polyanhydrides (for example polysuccinic anhydride) and polysiloxanes (for example trimethoxy) siloxane.) Another suitable entanglement agent is tris (alkoxy carbonylamino) triazine (available from Cytec Industries under the trademark TACT.) The curing agent may be combinations of these, particularly combinations including amino-plating interlacing agents. as melamine resins formaldehyde or urea formaldehyde resins are especially preferred. Combinations of tris (alkoxy carbonylamino) triazine with a melamine formaldehyde resin and / or a blocked isocyanate curing agent are also convenient and desirable. The coating composition employed in the practice of the invention may include a catalyst for improving the curing reaction. For example, when amino-plating compounds, especially monomeric melamines are used as a curing agent, a strong acid catalyst can be used to improve the curing reaction. These catalysts are well known in the art, and include without limitation p-toluenesulfonic acid, dinonylnaphthalene disulfonic acid, dodecylbenzenesulfonic acid, phenyl phosphate acid, monobutyl maleate, butyl phosphate, and hydroxy phosphate ester. Strong acid catalysts, they are often blocked, for example with an amine. Other catalysts that may be useful in the composition of the invention include Lewis acids, zinc salts and tin salts. A solvent can optionally be employed in the coating composition employed in the practice of the present invention. Although the composition employed according to the present invention can be used. For example in the form of substantially solid powder, or a dispersion, it is often convenient that the composition be in a substantially liquid state, which may be accompanied by the use of a solvent. This solvent should act as a solvent with respect to the components of the composition. In general, the solvent can be any organic solvent and / or water. In a preferred embodiment, the solvent is a polar organic solvent. More preferably, the solvent is chosen from polar aliphatic solvents or polar aromatic solvents. Even more preferable, the solvent is a ketone, ester, acetate, aprotic amide, sulfoxide, aprotic, aprotic amine or a combination of any of these. Examples of useful solvents include without limitation methyl ethyl ketone, methyl isobutyl ketone, m-amyl acetate, ethylene glycol butyl ether acetate, propylene glycol monomethyl ether acetate, xylene, N-methylpyrrolidone, mixtures of aromatic hydrocarbons and mixtures thereof. In another preferred embodiment, the solvent is water or a mixture of water with small amounts of cosolvents. In a preferred embodiment of the invention, the solvent is present in the coating composition, in an amount of from about 0.01 wt.% To about 99 wt.%, And preferably from about 10 wt.% To about 60 wt. and more preferably from about 30% by weight to about 50% by weight. Coating compositions can be applied to the article by any of a number of techniques well known in the art. These include, for example, robotic coating, dip coating, roller coating, curtain coating and the like. For automotive body panels, spray coating is preferred. Additional agents, for example surfactants, fillers, stabilizers, wetting oils, dispersing agents, adhesion promoters, UV absorbers, hindered amine light stabilizers, etc., can be incorporated into the coating composition. While these additives are well known in the prior art, the amount employed must be controlled to avoid adversely affecting the coating characteristics. The coating composition according to the invention is preferably used in high gloss coating and / or as the clear coating of a light-colored composite coating. High gloss coatings as used herein are coatings having 20% gloss as used herein are coatings having 20% gloss ASTM D523) or a DOl (ASTM E430) of at least 80. When the coating composition of the invention is employed as a high gloss pigmented paint coating, the pigment can be any organic or inorganic compounds or color materials, fillers, sheet metal or other inorganic materials, such as mica or aluminum flakes, and other materials of the type which in the art normally includes these coatings. Pigments and other insoluble particulate compounds such as fillers or fillers, are usually employed in the composition in an amount of 1% to 100%, based on the total weight of solids of the binder components (i.e. a proportion of pigment-a -Aglutinant of 0.1"to 1) . When the coating composition according to the invention is used as a clear coating of a color-plus-clear composite coating, the pigmented base coating composition can be any of a number of types well known in the art and does not require explanation in detail here. Polymers known in the art, useful in the basecoating compositions include acrylics, vinyls, polyurethanes, polycarbonates, polyesters, alkyds and polysiloxanes. Preferred polymers include acrylics and polyurethanes. In a preferred embodiment of the invention, the basecoating composition also utilizes a functional carbamate acrylic polymer. Basecoating polymers can be thermoplastic, but preferably are crosslinkable and comprise one or more types of interlacing functional groups. These groups include, for example, hydroxy, isocyanate amine, epoxy, vinyl acrylate, silane and acetoacetate. These groups may be masked or blocked in such a way that they are unblocked and available for the entanglement reaction under the desired curing conditions, generally at elevated temperatures. Useful crosslinkable functional groups include hydroxy, epoxy, acid, anhydride, silane, and acetoacetate groups. Preferred crosslinkable functional groups include hydroxy functional groups and amino functional groups. Basecoat polymers may be self-interlacing, or may require a separate crosslinking agent that is reactive with the functional groups of the polymer. When the polymer comprises hydroxy functional groups, for example the entanglement agent may be a plasto amino resin, isocyanates and blocked isocyanates (including isocyanurates) and functional anhydride acid interlacing agents. The coating compositions described herein are preferably subjected to conditions for curing the coating layers. Although various curing methods may be employed, heat curing is preferred. In general, heat curing is effected by exposing the coated article at elevated temperatures which is provided primarily by sources of radiant heat. Curing temperatures will vary depending on the particular block groups employed in the crosslinking agents, however in general they are in the range between 90 and 180 ° C. The first compounds according to the present invention are preferably reactive even at relatively low curing temperatures. Thus, in a preferred embodiment, the curing temperature is preferably between 115 and 150 ° C, and more preferably at a temperature between 115 and 140 ° C for a system catalyzed with blocked acid. For a system catalyzed with unblocked acid, the curing temperature is preferably between 80 and 100 ° C. The curing temperature will vary depending on the particular components used, and physical parameters such as the thickness of the layers, however, typical curing times are in the range of 15 to 60 minutes and preferably 15 to 25 minutes for systems catalysed with blocked acids and 10 to 20 minutes for unblocked acid catalyzed systems. The invention is further described in the following Examples. The Examples are merely illustrative and in no way limit the scope of the invention as described and claimed. All parts are parts by weight unless otherwise noted. EXAMPLES Example of the Invention A mixture of 136. g parts by weight of hydroxypropyl carbamate, 459 parts by weight of e-caprolactone, and 1.0 part by weight of stannous octoate, is heated in a convenient reactor under an inert atmosphere at 130 ° C. . After three hours at 130 ° C, 14.9 parts by weight of 2-ethyl-l, 3-hexanediol, 34.8 parts by weight of e-caprolactone, and 4.6 parts by weight of the aromatic solvent 100, are added to the reactor. The reaction mixture is then maintained at 130 ° C for four additional hours, then cool to room temperature. Comparative Example A mixture of 136.g parts by weight of hydroxypropyl carbamate, 459 parts by weight of e-caprolactone, and 1.0 part by weight of stannous octoate, is heated in a convenient reactor under an inert atmosphere at 130 ° C. After three hours at 130 ° C, the reaction mixture is cooled to room temperature. Testing Examples The example of the invention and the comparative example is maintained at room temperature. After three days, the Comparative Example solidifies to a solid, waxy solid. The Example of the Invention remains liquid. The Example of the Invention was then further tested in a freeze / thaw cycle test by storing the sample in a freezer at -5 ° C to bring the sample to -5 ° C, then letting the sample return to room temperature, the cycle of frozen / thawed is repeated 9 times. Each time, the sample returned to its original liquid state without the formation of any solid material. The invention has been described in detail with reference to preferred embodiments thereof. It will be understood, however, that variations and modifications may be made within the spirit and scope of the invention.

Claims

1. - A curable coating composition, characterized in that it comprises: (a) a compound having at least one carbamate group or terminal urea group, which is prepared by reacting together: (1) a compound comprising a terminal carbamate or urea group or a group that can become a carbamate or terminal urea group and a group that is reactive with (a) (2) and (2) μna lactone or a hydroxy carboxylic acid, (b) a compound having at least one branch point that is prepared by reacting as a whole: (1) a polyol having at least one branch point and (2) a lactone or a hydroxy carboxylic acid, and (c) a curing agent that is reactive with at least one compound (a) and component (b), where the carbamate group has a structure:

O-C-NHR wherein R is H or alkyl, and also wherein the terminal urea group has a structure

Or -NR'- -C II- -NHR "wherein R 'and R" each independently are H or alkyl, or R' and R "together form a heterocyclic ring structure 2. - Composition in accordance with Claim 1, characterized in that the compound (a) has at least two carbamate groups 3. - Composition according to claim 1, characterized in that the compound (a) has at least two functional groups selected from the group consisting of hydroxy functional groups , carbamate functional groups, terminal functional urea groups and combinations thereof

4. - Composition according to claim 1, characterized in that the preparation of compound (a) includes an additional step of reacting the product of (a) (1) and ( 5. (a) (2) with (a) (3) a polyisocyanate compound

5. - Composition according to claim 4, characterized in that the polyisocyanate compound is selected from the group consisting of: isophorone diisocyanate, hexamethylene diisocyanate to, isocyanurate of isophorone diisocyanate, isocyanurate of hexamethylene diisocyanate, and combinations thereof.

6. - Composition according to claim 1, characterized in that the compound (a) (1) has a carbamate group.

7. - Composition according to claim 1, characterized in that the group in the compound (a) (1) which is reactive with the compound (a) (2) is a hydroxyl group.

8. - Composition according to claim 1, characterized in that the compound (a) (1) has a group that is reactive with the compound (a) (2).

9. Composition according to claim 1, characterized in that the compound (a) (1) is a hydroxyalkyl carbamate.

10. Composition according to claim 9, characterized in that the hydroxyalkyl carbamate is a β-hydroxyalkyl carbamate.

11. Composition according to claim 1, characterized in that the compound (a) (1) is a hydroxyalkyl cyclic carbonate.

12. - Composition according to claim 1, characterized in that the compound (a) (2) is a lactone.

13. - Composition according to claim 1, characterized in that the compound (a) (2) is e-caprolactone.

14. Composition according to claim 12, characterized in that the equivalent ratio of lactone to equivalents of the group in the compound (a) (1) reactive with the lactone is from about 0.1: 1 to about 10: 1.

15. Composition according to claim 1, characterized in that the compound (b) (2) is a lactone.

16. Composition according to claim 1, characterized in that the compound (b) (2) is e-caprolactone.

17. Composition according to claim 1, characterized in that the compound (b) (1) is selected from the group consisting of: neopentyl glycol, 2-ethyl-l, 3-hexanediol, 2,5-dimethyl-2, 5- hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2,2-diethyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2,4-dimethyl- 2,4-pentanediol, 3, 3-dimethyl-1,2-butanediol, 1-ethyl-2-propyl-1,5-pentanediol, 2-ethyl-2-methyl-1, 3-propanediol, 2-methyl- 2,4-pentanediol, 1,2-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, and combinations thereof.

18. - Composition according to claim 1, characterized in that the compound (b) (1) is selected from the group consisting of: 2-ethyl-l, 3-hexanediol, 2, 2, 4-trimethyl-l, 3-pentanediol, 2-ethyl-2-methyl-1,3- propandiol, l-ethyl-2-propyl-l, 5-pentanediol, and combinations thereof.

19. Composition according to claim 1, characterized in that the preparation of the component (b) includes an additional step of reacting the product of (b) (1) and (b) (2) with (b) (3) a compound having a group that is reactive with a hydroxyl group of the reaction product of (b) (1) with (b) (2), wherein the compound (b) (3) provides a group reactive with the component ( c)

20. Composition according to claim 1, characterized in that the group provided by the compound (b) (3) is a terminal carbamate or urea group.

21. Composition according to claim 1, characterized in that component (c) includes a melamine formaldehyde resin.

22. Composition according to claim 1, characterized in that R and R "each are H.

23. - Composition according to claim 1, characterized in that the composition is a clear coating composition.

24. - Composition according to claim 1, characterized in that it also comprises a pigment.

25. Composition according to claim 1, characterized in that the amount of (b) (1) is from about 0.2 to about 10% based on the total weight of components (a) and (b).

26. An article comprising a substrate having a curing coating derived from a coating composition according to claim 1. 27.- A composition comprising: (a) a compound selected from the group consisting of compounds having the structures: -NHR " and its combinations; (b) a compound that has the structure: and mixtures thereof, wherein R 'and R "each independently are H or alkyl, or R' and R" together form a heterocyclic ring structure; R1, R2 are alkylene or arylalkylene; R3 is alkylene alkylarylene, arylene, or a structure including a cyanuric ring, a urethane group, a urea group, a carbodiimide group, a biuret structure, or an allophanate structure; n is from 1 to about 10; m is from 2 to about 6; and L is O, NH, or NR4, wherein R4 is an alkyl; R5 is a m-valent portion that has at least one branch point and X is a portion having an active hydrogen group. 28. A composition according to claim 27, characterized in that R and R 'each are H; R1, R2 are alkylene with 5 to 10 carbon atoms; R3 is alkylene or a structure including a cyanuric ring; n is from 1 to about 5; m is 2 or 3, L is O, NH, or NR4, wherein R4 is an alkyl with 1 to about 6 carbon atoms; R5 has from 2 to about 12 carbon atoms; and X is OH. 29. A composition, characterized in that it comprises: (a) a compound having at least one carbamate group or terminal urea group, which is prepared by reacting together: (1) a compound comprising a terminal carbamate or urea group or a group that can be converted to a terminal carbamate or urea group and a group that is reactive with (a) (2) and (2) a lactone or a hydroxy carboxylic acid, and (b) a compound having at least one branch point which is prepared by reacting as a whole: (1) a polyol having at least one branch point and (2) a lactone or a hydroxy carboxylic acid.