MXPA99006441A - Method for improving the accession of a repair coating to a previous coated substrate - Google Patents

Abstract

The present invention relates to: The invention provides a method for improving the adhesion of a repair coating to a coated substrate. It requires that when at least one coating composition is applied to a substrate, this coating composition has (a) a film forming component, with (i) an interlacing component that includes one or more amynoplast resins, and (ii) one or more polymers, having one or more functional groups, which are reactive with the interlacing component, (b) an adhesion enhancing additive, comprising one or more compounds containing the Sn (IV), (c) a catalyst for promoting a reaction between the crosslinking agent (i) and one or more polymers (ii). This at least one coating composition is cured to supply a coated substrate and one or more repair coatings are applied to the coated substrate. It is a preferred aspect of the invention, the one or more applied repair coatings are the same as this at least one coating composition. In a preferred aspect of the invention, this at least one coating composition of the invention further comprises: (d) an adhesion promoting compound, consisting of (i) a compound containing an epoxy group, and (ii) a component of a carboxy group monofunction

Description

METHOD TO IMPROVE THE ACCESSION OF A REPAIR COVER TO A SUBSTRATE COVERED PREVIOUSLY FIELD OF THE INVENTION The present invention relates to a method for improving the adhesion of a repair coating to a coated substrate, especially a substrate coated with a lighter colored composite coating. Also disclosed are the coating compositions for use in the claimed method and the articles resulting therefrom.

BACKGROUND AND COMPENDIUM OF THE INVENTION Substrates are coated for a wide variety of reasons. Coatings can be applied to protect the underlying substrate from environmental effects and / or provide a pleasant visual appearance. Dual-purpose coatings are particularly common in the automotive industry, where environmental resistance, durability and appearance are the minimum requirements for original equipment coatings applied at the assembly plant by the automaker. Many types of coatings and coatings systems have been developed in an attempt to meet the requirements of the automobile industry. The lighter colored composite coatings are widely used in the coatings technique. They are particularly convenient when exceptional brightness, color depth, image distinction or special metallic effects are required. The automobile industry has made extensive use of lighter colored coatings for automotive body panels. As used herein, the term "lighter colored compound" refers to composite coating systems that require the application of a first coating, typically a basic color coating, followed by the application of a second coating, generally a coating of course, on the first uncured or "wet" coating. The first and second coatings applied are then cured. Thus, such systems are often described as "wet on wet" or "two coatings / one baked". Drying processes that do not cure completely can be used between the application of the coatings. Clear coatings, in lighter color systems, must have an extremely high degree of clarity, in order to achieve the desired visual effects. High gloss coatings also require a low degree of visual aberrations on the surface, in order to achieve the desired visual effect, such as high image distinction (DOI). As a result, clear coatings of lighter color systems are especially susceptible to the phenomenon known as environmental etching, that is, stains or marks on or in the clear finish, which often can not be removed by rubbing. Many compositions have been proposed for use as the clear coating of a lighter colored composite coating. However, clear coatings of the prior art often suffer from disadvantages, such as a lower coating capacity, problems of compatibility with the basic color coating, problems of solubility, lack of adhesion to the underlying base coat, lack of adhesion to the repair coatings applied to the lighter colored composite coating, following the clear coating cure and / or insufficient resistance to environmental etching. Clear coating compositions that exhibit many advantages over the prior art compositions, especially with respect to environmental etching, were described in the U.A.A. Patent Nos. 5,474,811 and 5,356,669. The clear coating compositions described comprise a first component, comprising a polymer backbone having at least one carbamate functional group, and a second component comprising a compound having a plurality of functional groups that are reactive with the groups of carbamate Nevertheless, in spite of the previous improvements, certain of the previous problems remain. In particular, some of the composite coatings exhibit a lower degree of adhesion to the applied repair coatings following the curing of the composite coating. The inferior or inadequate adhesion of the repair coatings to the composite coating is a separate and distinct problem from the delamination of the general composite coating to the underlying substrate. The type of the repair coating and the method used to repair a defect on a finished surface typically depends on when and how the defect occurred. Defects and / or imperfections that occur during the application and / or cure of the composite coating are corrected by means of "on-line" repair processes. Online repair processes typically involve the application of one or more additional layers of the composite coating to the surface of one or more previously applied and cured layers of the composite coating. The additional layers are cured in an identical manner to the previously applied and cured layers. Multiple passes of the coated and cured product, which contains the defect, through the application line of the composite coating and the furnace system, achieve this type of repair. It will be appreciated that the repair coating, in this case, is the composite coating itself or its components. The repair can be made on a component of the basic coating, the component of the top coating, or the combination thereof, ie the composite coating of lighter color. In any case, the online repair is done with the application of a coating that is identical to the coating layer or layers to be repaired. Surface or sand preparation is not allowed before the application of the additional composite coating layers or their components. The "repair coating", that is, the composite coating, must exhibit excellent adhesion to the layers of the applied and previously cured composite coating, without any treatment with sand or preparation of the previously applied and cured layers.

The defects and / or imperfections that result from the manufacturing processes of the product are solved with the "end of line" repair processes. These end-of-line repair processes typically occur after the addition of the product components that have melting and / or deformation temperatures lower than the baking temperature of the lighter colored composite coating. Thus, a repair coating, which has a cure temperature lower than the lowest deformation temperature of the component, is employed. As a result, end-of-line repair coatings have significantly lower cure temperatures than those of composite coatings. Some treatment with sand and / or surface preparation can be allowed before the application of the end-of-line repair coating. Finally, "refinishing" repair processes are used to rectify defects that occur after the product leaves the manufacturing facility. Refinishing products are typically applied after a substantial treatment with sand from the surface to be repaired. Refinish coatings typically cure at lower temperatures than those of lighter colored composite coatings, but are designed to provide optimum performance benefits. Such coatings can be expensive and require specialized application equipment. Manufacturers of composite coatings are particularly interested in the requirements of online repair processes. Improvements in adhesion of the in-line repair coating must be provided in conjunction with the required performance properties of the composite coating, such as appearance, durability and etch resistance, among others. It is desirable to provide a method for improving adhesion of repair coatings applied to a substrate previously coated in an online repair process. Such a method will provide advantages of quality, appearance and cost. It would also be advantageous to provide a composite coating that provides desired performance properties, but which is also capable of performance as a repair coating for use in online repair processes, without sand treatment or surface preparation of the coated substrate containing the defect The present invention achieves these and other objectives. The invention is directed to a method for improving the adhesion of a repair coating applied to a substrate previously coated in an online repair process. The invention further provides coating compositions for use in the claimed method and the coated articles resulting therefrom are also provided. The method of the invention for improving the adhesion of a repair coating to a coated substrate requires that at least one coating composition be applied to a substrate, wherein this coating composition comprises: (a) a film forming component, which includes (i) an interlacing component, comprising one or more aminoplast resins, and (ii) one or more polymers having one or more functional groups that are reactive with the interlacing component; (b) an adhesion enhancing additive, comprising one or more compounds containing the Sn (IV), (c) a catalyst for promoting a reaction between the crosslinking agent (i) and one or more polymers (ii). This at least one coating composition is cured to supply a coated substrate and one or more repair coatings are applied to the coated substrate. In a preferred aspect of the invention, the one or more applied repair coatings are the same as this at least one coating composition. The coating composition of the invention, which has improved adhesion to repair coatings, requires: (a) a film-forming component, consisting of (i) an interlacing component consisting of one or more aminoplast resins, and (ii) one or more polymers having one or more functional groups that are reactive with one or more aminoplast resins; (b) an adhesion enhancing additive, comprising one or more compounds containing the Sn (IV), and (c) a catalyst, to promote the reaction between this one or more aminoplast resins (i) and one or more polymers (ii), this catalyst comprises one or more acidic compounds, which are at least partially blocked. In a preferred aspect of the invention, the composition further comprises (d) an adhesion-promoting component, consisting of (i) a component containing an epoxy group, and (ii) a component of the monofunctional carboxy group. Finally, the invention provides a coated article comprising an article having a substrate with a coating cured thereon, this cured coating comprising the result of curing of at least one coating composition of the invention.

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for improving the adhesion of a repair coating to a coated substrate. The method requires that at least one coating composition be applied to a substrate, wherein this coating composition comprises: (a) (a) a film-forming component, which includes (i) an interlacing component, comprising one or more aminoplast resins, and (ii) one or more polymers having one or more functional groups that are reactive with the interlacing component; (b) an adhesion enhancing additive, comprising one or more compounds containing the Sn (IV), (c) a catalyst for promoting a reaction between the crosslinking agent (i) and the polymer (ii). This at least one coating composition is cured to supply a coated substrate and one or more repair coatings are applied to the coated substrate. Substrates suitable for use in the method of the invention include metal, wood, plastic, composites, alloys and combinations thereof. Substrates commonly found in the automotive industry are preferred, especially those that are used in the production of automotive body panels. More preferred are metal, plastic, composites, alloys and their combinations. Suitable substrates can be prepared as they are commonly treated in the automotive industry. The substrates can be prepared, phosphated, coated by electrodeposition and / or washed or prepared as desired. The washing followed by the electrodeposition coating is the most preferred. The coating composition of the invention which is applied to the substrate comprises a component (a) which forms films, an additive (b) which improves adhesion, which comprises one or more compounds containing Sn (IV), and a catalyst ( c), to promote a reaction between the parts of the component (a) that forms the film. This component (a) forming the film comprises an interlacing component (i) which comprises one or more aminoplast resins, and one or more polymers (ii) having one or more functional groups, which are reactive with the interlacing component (i) ). The component (a) that forms the film results in an interlaced or network polymer, when it is subjected to sufficient conditions to perform the suction. The reastives that comprise the component (a) that forms the film are multifunctional components, such as bifunctional, trifunctional, etc. Mixtures of such multifunctional components, especially mixtures of bifunctional and trifunctional components, are especially preferred. The monofunctional components are not convenient in the component (a) that forms the film. The interlacing component (i) comprises one or more aminoplast resins The aminoplast is used herein to refer to amino resins or thermosetting resins obtained by combining an aldehyde with an amino group-containing compound (-NH 2) • Illustrative compounds containing a amino groups are urea, melamine, benzoguanamine, dihydroxyethylurea, acetoguanamine, acrylamide and mixtures thereof Preferred compounds containing the amino group are urea and melamine Suitable amino resins can be polymeric or onomeric.They can have astyl methylol groups or are totally or partially alkylated are methylalkyloxy groups Alsoholes having one to six sarbono atoms are suitable for the alkylation of the amino resins, with methanol, isobutanol and n-butanol being preferred. their use as the interlacing component (i) are at least partially alkylated melamines. s preferred are those which are fully alkylated, especially those having alkyl groups of C14. The interlacing component (i) will consist of one or more amino resins, including mixtures of suitable amino resins. The component (a) that forms the film, further comprising one or more polymers (ii). Suitable polymers (ii) include the oligomeric compounds, polymeric compounds and mixtures thereof, having one or more functional groups, which are reactive with the amino resin of the linker component (i). At least two functional groups are preferred. Illustrative functional groups that are reactive with the amino resins include the hydroxyl, carbamate, carboxyl and amide. Exemplary polymers having such functional groups include alkyds, polyesters, epoxies, carbamates, acrylics, vinyls, and mixtures thereof. Preferred as the polymer (ii) are those compounds having two or more carbamate functional groups. Preferably, the polymer (ii) comprises a compound selected from the group consisting of oligomers and polymers, having more than one carbamate group or more than one urea group, or more than one group that can be converted to a group of carbamate or urea. The oligomers typically have a molecular weight between 148 and 2000, the preferred molecular weight for the oligomers is between 900 and 1092; the polymers typically have a number average molecular weight between 2,000 and 20,000, with the preferred number average molecular weight of the polymers being between 4000 and 6000. Mixtures of these oligomers and polymers can be used. as the polymer (ii). The number average molecular weight can be determined by the gel permeation chromatography (GPC) method, which uses a polystyrene standard. The carbamate or urea content of the polymer in a number average molecular weight per equivalent of the carbamate or urea functionality will generally be between 120 and 1200 and preferably between 300 and 800. The carbamate groups can generally be characterized by the formula: OR II O - C - NHR where R is H or alkyl, preferably with 1 to 4 carbon atoms. Preferably, R is H methyl more preferably, R is H. The urea groups can be characterized generally by the formula: OR II - NR «- C - NHR where R1 and R "represent, independently, H or alkyl preferably with 1 to 4 carbon atoms, or R 'and R", can together form a heterocyclic ring structure (for example, when R' and R "form, for example , an ethylene bridge).

Groups that can be converted to the carbamate include the cis-carbonate groups, epoxy groups and unsaturated bonds. The cyclic carbonate groups can be converted to the carbamate groups by reaction with ammonia or a primary amine, which opens the cyhalise carbonate ring to form a β-hydroxy carbamate. The epoxy groups can be converted to the carbamate groups by first converting a n-cyclic carbonate group by reaction with the C0. This can be done at any pressure, from atmospheric to supercritical CO2 pressures, but preferably under high pressures (for example from 4.2 to 10.5 kg / cm2). The temperature for this reaction is preferably 60 to 150SC. Useful catalysts include any that activates an oxirane ring, such as a tertiary amine or quaternary salts (e.g., tetramethyl ammonium bromide), combinations of complex organotin halides, and alkyl phosphonium halides (e.g. ) 3SnI, BU4SnI, BU4PI and (CH3) PI, potassium salts (for example, 2CO3, KI), preferably in combination with crown ethers, tin octoate, calcium ostoate, and the like The cyclic carbonate group can then They are converted to a sarbamate group, but they were broken down first. "Any unsaturated bond can be converted to the carbamate groups, first by reaction with the peroxide to convert it to an epoxy group, then with the CO2 to form a cyclic carbonate, and then with ammonia or a primary amine, to form the carbamate Oligomeric compounds useful as the compound (i) and having more than one carbamate functional group, have the general formula: OR II X- C - NHR !, where X is 0, or NH, Ri is H or alkyl with 1 to 4 carbon atoms. The compounds useful as the oligomeric compound (i), according to the invention, can be prepared in a variety of ways. The carbamate can be primary, ending in a NH2 group, or secondary, ending in an NHC group. In a preferred embodiment, the carbamate is primary. One way to prepare the oligomeric compounds, useful as the polymer (ii) is to react an alcohol (the 'alcohol1 is defined herein as having one or more OH groups) with the urea, to form a compound with the carbamate groups. This reaction is achieved by heating a mixture of alcohol and ureas. This reaction is also carried out under heat, preferably in the presence of a catalyst, as is known in the art. Another technique is the reaction of an alcohol with the cyanic acid to form a compound with the primary carbamate groups (i.e., unsubstituted carbamates). The carbamates can also be prepared by the reaction of an alcohol with phosgene or equivalent materials, and then with ammonia to form a compound having primary carbamate groups, or by reacting an alcohol with phosgene or equivalent materials and then a primary amine, to form a compound having secondary carbamate groups. Another approach is to react an isocyanate (e.g., HDI, IPDI) with a compound, such as hydroxypropyl carbamate, to form an isocyanate derivative capped to carbamate. Finally, the carbamates can be prepared by an approach to transcarbamylation, wherein an alcohol is reacted with an alkyl carbamate (for example methyl carbamate, ethyl carbamate, butyl sarbamate) to form a compound containing a group of primary carbamate. This reassignment is carried out under salor, preferably in the presence of a catalyst, such as an organometallic catalyst (for example dibutyltin dilaurate). Other techniques for preparing carbamates are also known in the art and are described, for example, in P. Adams &; F. Barón, "Carbamic Acid Esters", Chemical Review. v. 65, 1965. Various alcohols can be used in the preparation of the useful sarbamate moieties as a moiety (i), according to the invention. They generally have from 1 to 200 carbon atoms, preferably from 1 to 60 carbon atoms, and can be monofunctional or polyfunctional (preferably, a functionality of 2 to 3), aliphatic, aromatic or cycloaliphatic. They may contain just OH groups, or may contain OH groups plus heteroatoms, such as O, S, Si, N, P and other groups, such as ester groups, ether groups, amino groups or unsaturated sites. Examples of useful alcohols include 1,6-hexanediol, 1,2-hexanediol, 2-ethyl-l, 3-hexanediol, ethyl-propyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 2, 2, 4-trimethyl-1,3-pentanediol, 2,4,7,9-tetramethyl-5-decin-4,7-diol, 1,3-dihydroxyacetone dimer, 2-butene-1,4-diol, pantothenol, dimethyltartrate, pentaethylene glycol, dimethyl-silyl-dipropanol and 2,2'-thioethanol. Suitable polymeric compounds for use as the filler (i), are selected from the group consisting of polymers of polyester, epoxy, alkyd, urethane, asyllos, polyamide, and polysilane, and their mixtures, in. that the polymer has more than one fungal group of sarbamate attached thereto. In a preferred embodiment, the compound (i) comprises a functional asymmetric carbamate polymer, represented by randomly repeating units, according to the following formula (A): In the previous formula, R represents H or C3. R 'represents H, alkyl, preferably with 1 to 6 carbon atoms, or sisloalkyl, preferably up to 6 sarbone atoms in the ring. It will be understood that the terms alkyl and cycloalkyl include alkyl and substituted cycloalkyl, such as alkyl or cisloalkyl substituted by halogen. Substitutes that have an adverse impasse in the properties of the sweat material, however, will be avoided. For example, ether enlases are thought to be susceptible to light-induced hydrolysis and should be avoided at locations that only select ether enlases in the entanglement matrix. The values of x and y represent percentages by weight, with x being from 10 to 90 percent and preferably from 20 to 50 percent, and being from 90 to 10 percent and preferably from 80 to 50 percent. In the formula, A represents repeated units derived from one or more ethylenically unsaturated monomers. These monomers for the polymerization are asrylic monomers are known in the art. They include the alkyl esters of acrylic acid or metasylysis, for example ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, butyl methacrylate, isodecyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, and the like; and vinyl monomers, such as unsaturated m-tetramethyl-xylene isocyanate (sold by American Cyanamid as TMI®), vinyl toluene, styrene, styrenide derivatives, such as a-methyl styrene, t-butyl styrene, and similar. L represents a divalent linker group, preferably an aliphatic linker group is 1 to 8 atoms of sarbon, sisalifatiso or aromatiso with 6 to 10 carbon atoms. Examples of L include the following structure (B): wherein R = CH2, C2H4, C3H6, C4H3, and the like. In a preferred embodiment, -L- is represented by -COO-L ', where L' is a divalent linker group. Thus, in a preferred embodiment of the invention, the somatic polymorph (i) is represented by randomly repeated units, in accordance with the following formula (C): In this formula, R, R ', A, x and y have the previous definitions. L 'can be a divalent aliphatic linker group, preferably they are 1 to 8 sarbono atoms, for example - (CH2) -, - (CH2) 2 ~ / - (^ 2) 4-, and the like, or a sisalifatiso linker group divalent, preferably they are up to 8 atoms of sarbono, for example sislohexilo, and the like. However, other divalent linker groups can be used, depending on the tisane used to prepare the polymer. For example, if hydroxyalkyl sarbamate is assed in a functional acrylic isosanate polymer, the linker group L * will include a urethane linkage, -NHCOO-, as a residue of the isocyanate group. This functional acrylic carbamate polymer is described in U.S. Patent No. 5,356,669, which is incorporated herein by reference. The polymer (ii) used in the composition of the invention can be prepared in a variety of ways. One way to prepare the polymers is to prepare an acrylic monomer having carbamate functionality in the ester portion of the monomer. Such monomers are well known in the art and are disclosed, for example, in U.S. Patent Nos. 3,479,328, 3,674,838, 4,126,747, 4,279,833 and 4,340,497, the descriptions of which are incorporated herein by reference. A synthesis method involves the reation of a hydroxy ester is urea, to form the sarbamoyloxy sarboxylate (it is desir, the carbamate-modified asyllosis). Another synthetic method reacts an ester of a, b-unsaturated acid with a hydroxy carbamate ester to form the carboxyl carbamoyloxy. Still another implicit tetanus, the formation of a hydroxyalkyl sarbamate by the reassessment of ammonia, or a primary or secondary amine or diamine, is a sisal sarbonate, such as ethylene sarbonate. The hydroxyl group in the hydroxyalkyl sarbamate is then esterified by the reassumption of the acrylic acid or metasyllabic to form the monomer. Other methods of preparing modified asymylide monomers are sarbamate, which are broken down in the art and can also be used. The acrylic monomer can then be polymerized together with other ethylenically unsaturated monomers, if desired, by well-known techniques in the art. An alternative route to prepare an asymylid polymer for use as the somponent (i) in the embodiment of the invention, is to react an already formed polymer, such as an acrylic polymer, are another somponent to form a carbamate functional group attached to the backbone of the polymer, as described in U.S. Patent No. 4,758,632, the disclosure of which is incorporated herein by reference. A technique for preparing such asyllic polymers involves the thermal decomposition of urea (to release the ammonia and HNCO), in the presence of a polymer or a hydroxy-functional acrylic copolymer, to form a functional acrylic sarbamate polymer. Another implicit tanstan reacuring the hydroxyl group of a hydroxyalkyl sarbamate is the isocyanate group of an asyrsynth or vinyl funsional isosianate monomer to form the functional acrylic acid of carbamate. Functional acrylics of sarbamate are sonosides in the art and are described, for example, in the patent of E. U. A., No. 4,301,257, whose description is insorporated here as referensia. The vinyl monomers of isosianate are well known in the art and include the unsaturated m-tetramethyl-xylene isosianate (sold by Amerisan Cyanamid as TMI®). Still another technique is to react the group of sarbonate sisliso in a cyclism funsional sarbonate with ammonia or other primary amine, in order to form the acrylic sarisonic funsional. The asymylic acid-free sarbonate serous polymers are known in the art and are described, for example, in U.S. Patent No. 2,979,514, the description of which is herein incorporated by reference. A more difficult, but theoretically possible, way to prepare the polymer will be to trans-esterify an acrylate polymer with a hydroxyalkyl carbamate. Groups capable of forming urea groups include amino groups which can be converted to urea groups by reaction with a monoisocyanate (for example methyl isocyanate), to form a secondary urea group, or with cyanide acid (the sual can be formed in situ by the thermal decomposition of urea) to form a primary urea group. This reaction preferably occurs in the presence of a satallizer, as is known in the art. An amino group can also resonate are phosgene and then ammonia to form a compound having one or more primary urea groups, or by the reassessment of an amino group with phosgene and then a primary amine, to form a compound having a group of secondary urea. Another approach is to react an isosyanate with a hydroxy urea compound, to form an isocyanate derivative capped with urea. For example, one isosyanate group in the toluene diisocyanate can be reacted with hydroxyethyl ethylene urea, followed by the reassessment of the other isosiana group is a polyols exogenous, to form a hydroxy sarbamate. In addition to the somponent (a) that forms the pelvis, this at least one rewind somposisance includes an additive (b) that improves adhesion, which includes one or more stains containing the Sn (IV). Suitable compounds for use as additive (b) will generally be of the formula: (X) n - Sn - (R) m where m, n = 1 to 3, m + n = 4 or 5, X is at least one C1 alkyl group, preferably a C6-6 alkyl group, more preferably a C4 or Cs alkyl group, R may be a base conjugated from an acid, or where the polymers are formed as discussed below, R can be (X ') r O - Sn - (R ') where q = 0 to 2, r = 1-3, r + q = 3 or 4, X 'is selected from previous X, and R * is selession from previous X or R, preferably from R. Asides adesuados for use as the conjugate base of R include all compounds containing active hydrogen, including water, alcohols and halides, carboxylic acids, phosphoric acid, mono- or di-acid phosphates substituted by alkyl or aryl, as well as alkyl or aryl phosphonates, sulfonates substituted by aryl or alkyl, substituted aryl or alkyl sulfates. Especially preferred are phosphoric and / or sulphonic acids substituted by aryl and / or alkyl. In the case where the acid contains more than one active hydrogen, polymers can be formed. These polymers can vary from 2 to 3 tin atoms (stannoxanes) up to 30 tin atoms. A common example is water is a dibutyl tin, which forms the dibutyl tin oxide polymer. It will be appreciated that such polymers are not found within the above structures, that they are intended to be structures idealized only in the case of the polymers that are Sn and / or the poliestannoxanes. In addition, a so-biosión, or mezsla, of asidos can be used in order to achieve a balance of properties. Illustrative examples of compounds which are Sn (IV), added to their use as additive (b), are dibutyltin oxide (DBTO), dibutyltin diacetate (DBTDA), stannoxane and FC-4800, a compound available somersially from Elf Atoshem of Philadelphia, PA. However, the additive (b) which improves adhesion is preferably selected from the dibutyl tin oxide group and the dibutyl tin diastate. More preferably, the additive (b) is the dibutyl tin diastate. The additive (b) will normally be used in amounts of 0.05 to 5.0% by weight, based on the total amount of the solid slaro replenishment. Preferably, the additive (b) will be used in sanctity from 0.1 to 2.0 and, more preferably, from 0.2 to 1.0% by weight, are based on the total sanctity of the clear solid re-rise. A catalyst (c) for promoting the reaction between the interlacing agent (i) and the polymer (ii) (must be used in conjunction with the additive (b) which improves adhesion.) The satalycer (s) can be sequestered from strong acids, such as p-toluenesulfoniso acid, acid dinonylnaphthalene disulfoniso, acid dodesilbensensulfoniso, phenyl acid phosphate, monobutyl maleate, butyl phosphate and hydroxy phosphate ester.However, the sachallizer (s) must be blocked sompleta or at least parsially.Typety blocking agents are amines and epoxides.Amine blocking agents are preferred.A most preferred satallizer for use as the satallizer (s) is the acid dodesilbensensulfoniso, blocked are an amine, such as diisopropanolamine or dimethyloxazolidine The satallizer (s) will normally be used in sanctities of 0.5 to 8.0 per cent by weight, based on the total amount of solid clear coating. e, catalyst (c) will be used in sanctities from 0.1 to 4.0 and, more preferably, from 0.5 to 2.0, I feel in that, they are the basis in the total sanctity of the solid slaro replenishment. Optionally, the invention reuptake somposisance can also comprise a component (d) that promotes adhesion, which consists of (i) an epoxy group, which is the somponent and (ii) a somponent which is a monofunctional sarboxi group. The subsomponent (i) includes one or more epoxide groups. Epoxides are well known in the art. The epoxide can be of the general formula: where i, R2, R3 and R4 are each, independently, H (are the sondisión that at least one of R? ~ R4, is different from H), a radisal organelle, the sual can be polimériso or not polimériso, and can be unsaturation or heteroatoms, or one of R or R2 together they are one of R3 or R4 can form a semisyl ring, the sual can contain unsaturation and / or heteroatoms. Although essentially any epoxide can be used in the practice of the present invention, this epoxide is preferably substantially free of groups that are reactive with either of the two components, which are reactive with each other to form the urethane linkages. By "substantially free" of such groups, it is understood that the degree of reaction between their two reactants to form the urethane linkages and any reactive component in the epoxide is sufficiently low to avoid any adverse impact not desired in the adhesion properties between the coating. Useful epoxides can be prepared from alcohols, for example butanol, trimethylolpropane, by the reaction with an epihalohydrin (for example epichlorohydrin), or by the reassessment of an allyl group are the peroxide. Oligomeric or polymeric polyepoxides, such as acrylic polymers or oligomers, which are glycidyl metasilicate or epoxy-terminated polyglycidyl ethers, such as diglycidyl ether of Bisphenol A (DGEBPA), may also be used. The epoxidized polyurethane resins or polyester resins can be prepared by the reaction of polyurethanes or polyesters containing OH groups, as is sonoside in the art, they are an epihalohydrin. The epoxides can also be prepared by the reaction of an isocyanate-terminated component, such as a polyisocyanate or monomeric polymer or oligomer with the glycidol. Other conoside polyepoxides, for example epoxy-novolac resins, can also be used. In a preferred embodiment, the epoxide is a polymer or oligomer containing acrylic, preferably deriving its epoxy groups from the monomer of glisidyl methacrylate, glisidyl asrilate, allyl-glycidyl ether, sislohexyl-monoepoxy metasrilate, the epoxide of the dimer of the sislopentadiene methacrylate, or the epoxidized butadiene, more preferably glycidyl methacrylate. In another preferred embodiment, both the epoxy-containing component and one of the somatomers which reasserts to form urethane enlases are ashylised polymers or oligomers. The epoxide is preferably present in the coating somposision in an amount of 0.0001 to 0.05 equivalents of epoxy per 100 g of resin. In a preferred embodiment, the composition of the present invention also includes a component (ii) that contains a monofunctional acid group, the sual being different from the satallizer (s). Any type of monofunsional solid can be used, which includes the Bronsted asses. The Lewis acids are preferred. The asses can be inorganic acids, but the more organelles are preferred. Several types of monophunional octoside may be used, such as phenolics, sisalis or hydroxy acids or carboxylic acids, with carboxylic acids being preferred. Examples of suitable monofunctional acids include octanoic acid, benziso acid, acetic acid, hexanoid acid or bensylysid acid.

Illustrative examples of acid-containing asrichides are the copolymers of an ethylenically unsaturated monomer, which are an asido group. The sopolymers can be prepared using conventional theses, such as the free radisal polymerization or the anionized polymerization in, for example, a batch or semi-batch process. One or more other ethylenically unsaturated monomers that are not an asido group can be insorporated in the polymer that is asidoid. Examples of ethylenically unsaturated monomers which are an acidic group may be alkyl esters of acrylic acid or metasylic acid, for example ethyl asrilate, butyl acrylate, 2-ethylhexyl acrylate, butyl methacrylate, isodecyl methacrylate, hydroxyethyl methacrylate. , hydroxypropyl asrilate, and the like; vinyl monomers, such as styrene, vinyl toluene and the like. The polymerizable monomers containing groups which will react are the acid group, under the selected addition reaction conditions, should be avoided, since they produce a non-gelled prodrug. The acid component is preferably present in an amount of 0 to 0.5 equivalents of acid per 100 g of resin solids and, more preferably, 0.00008 to 0.008 equivalents per 100 g of the resin solids.

In a preferred embodiment of the invention, the polymer (i) is a sarisic acid-based grinding resin, and the somponent which includes one or more epoxy groups is an epoxy-based asrylic resin. Such an epoxy asrylic resin preferably includes one or more of the somatomers of lauryl methacrylate, 2-ethylhexyl as- rylate, 2-ethylhexyl metas- rylate, or butyl as- rylate. The epoxy equivalent weight, the weight, and the glass transition temperature of the epoxy acrylic resin are adjusted by varying the monomer line to optimize the performance in the partiscular resorption composition by techniques known in the art. A. The coating composition, according to the present invention, can be used, for example, in the form of a substantially solid powder, or dispersion, and optionally a solvent can be used in the composition of the present invention. It is often convenient that the composition be in a substantially liquid state, the sual can be achieved by the use of a solvent. In general, depending on the solubility faces of component (A), 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 a polar aliphatic solvent or a polar aromatic solvent. Even more preferably, the solvent is a ketone, ester, acetate, alcohol, aprotic amide, sulfoxide aprhotis, or aprotic amine. Examples of useful solvents include methyl ethyl ketone, methyl isobutyl syntone, n-amyl acetate, ethylene glycol butyl ether acetate, propylene glycol monomethyl ether acetate, xylene, n-methyl pyrrolidone ( NMP), isobutanol (iBuOH), methanol (MeOH), propylene sarbonate (PC), or mixtures of aromatic hydrocarbons. Alternatively, the solvent may be water or a mixture of water and small sanctities of so-so solvents. Additional ingredients may be added to the reuptake somposisance, such as, but not limited to, pigments, rheology control agents, flow control additives, ultraviolet absorbers, and obstructed amine light stabilizers. In a preferred embodiment of the invention, the composition of the invention is used as a pigmented resurfacing composition or a clear coating composition, and more preferably a coating composition. In such somposision, the solvent may be present in the inventive composition at a sanity of about 0.01 to 99 per cent by weight, preferably about 10 to 60 per cent by weight and, more preferably, from about 30 to 50 weight percent. In a particularly preferred embodiment, the composition of the invention is used as a slat and / or insolubrate overlay composition on a pigmented base overlay as part of a lighter colored composite coating. Such sunk reubstances are popular in their depth of solor and bright fluid superfisial apariensia. They also teach a wide aseptasión particularly in the field of automotive coatings. The composition of the invention can also be used as the basic re-coating of a lighter colored composite coating. A) Yes. In the inventive method, this at least one embodiment of the invention can be aplimated as a basic coating or as a clear coating. The repair coating can be applied as a repair to a base re-cover, a clear re-cover or a composite coating that has both the base coat and the clear coat. It will be appreciated that the repair re-cover may be a base re-raise, a slaro re-raise or both. More preferably, the coating compositions of the invention will serve as a clear coating and a repair re-covering for the slats. When using a slaro-coating, the sompositions of the invention will normally aply on a pigmented somposision of the base and , more preferably, a base water-carrying base solution, as described in US Patent No. 34,730, incorporated herein by reference, Other pigmented basecoat compositions for such overlays are well sonosed in the art and do not require extrusion in Its details Polymers found in the art useful in base coatings applications include asiles, vinyls, polyurethanes, polycarbonates, polyesters, alkyd and polysiloxanes.A preferred polymer is an acrylic polymer.The coating compositions can be coated on the article by c Any of a number of well-known techniques in the art. They include, for example, spray back-coating, dip coating, roll coating, curtain coating, and the like. For automotive body panels, spray coatings are preferred.

After the application, the replenishment assumption of the invention is submitted to sufficient sums to supply a cured film. Typically, the coated substrate is subjected to exposure to a radiant heat source for a period of time such that the interlacing of the component (a) forming the film is initiated and completed. Curing temperatures will vary depending on the deposition of the applied coatings, however, they generally vary from 93 to 20 cc, preferably between 115 and 1772 C, and more preferably between 121 and 14 cc. The cure time will vary depending on the partiscular components used and the physical parameters, such as the thickness of the layers, however, typical cure times will vary from 15 to 60 minutes. The method of the invention improves the adhesion of a repair coating to a coated substrate. The repair coatings applied to the coated substrate that result from the application of the backfill somposision of the reinforcement can be those aplisted in the online repair processes, the end-of-line repair processes as well as the refinishing processes. However, significant improvements in adhesion are achieved by suing the repair overlay is that typically smoothed in a process of online repairs. Although other types of repair coatings that are sound in the art can be aplimated, a preferred type of repair coating is the coating composition of the invention. After the aplissation of the repairing reflection, it is subjected to sufficient sonsions to effect the cure. In the most preferred case, the repair coating will be swept as indicated for the coating composition of the invention. The invention will be described below in the following non-limiting examples.

EXAMPLES Examples 2 to 4 are based on the clear coat URECLEAR®1, prepared without catalyst, and were prepared by adding the identified materials to the clear coating under agitation.

A clear commercial coating, available from BASF Corporation as R10CG060F.

Table l Material Control (g) Example 2 Example 3 Example 4 Example 5 M igal) g) "R10CG06ÓF 140775 R10CG060F 1407.5 1407.5 1407.5 1407.5 without catalyst DDBSA2 28.0 25.6 Blocked FC48003 12.0 DBTDA4 16.8 11.2 2.8 isobutanol 7.2 16.8 Test panels were prepared for the # 1 adhesion test by spray coating electrocoated steel panels, with approximately 20.32 microns of black baseback (E86KE524 Ebony Black from BASF Corp.). After 5-20 minutes, samples from the ? DDBS blocked is a DDBSA astivo at 25% and is available from King Industries (Norwalk, CT) as Nacure XC6206 3 FC4800 is 40% weight / weight of Fascat 4800 in N-methylpyrrolidone. Fascat 4800 is commercially available from Elf-Atochem of Philadelphia, PA. * 100% dibutyl-eetane diacetate slaro back-up from Table 1 above was spray-applied by a spray coating at a thickness of 45.72 to 50.8 slides. After 5 to 20 minutes, the panels were baked for 10 minutes (metal temperature time) at 1212C. After cooling, a superior repair overlap of 10.16 millimeters was spray-applied as a black base re-cover (E86KE524 Ebony Blask from BASF Corp). No sand treatment or superfisial preparation was performed before the aplissation of the repair re-coating. 5 to 20 minutes after the liming of the repair lining, the slaro luster samples of Table 1 were spray-applied to a thickness of 45.72 to 50.8 microns. After 5 to 20 minutes, the resulting panels were baked for 10 minutes (metal temperature time) to 1212C. Test panels were prepared for the # 2 adhesion test as for the # 1 adhesion test, except, however, that after the first application of the samples from Table 1, the panels were baked for 50 minutes (time a metal temperature) to 146SC. After the application of the repair composite coating, the panels were baked for 11 minutes (time at metal temperature) at 126.62C.

Test panels for the evaluation of the appearance were prepared as indicated in the # 1 adhesion test, except, however, that after the application of the samples in Table 1, the panels were baked for 20 minutes (time a metal temperature) to 132se and the repair composite coating was not applied.

Table 2 Control Test Example 2 Example 3 Example 4 Example 5 Stability 4. 0 24. 7 11. 5 0. 6 8. 5 Ford Cup # 4 (sec.) Adhesion # 1 100% 0 0 Not cured 0 Adhesion # 2 0 10% 0 0 Appearance 66. 0 53. 7 70. 4 66. 9 The stability reflects the difference in viscosity between the initial sample and that of a sample exposed to 60se. The viscosity units are the second in a Ford # 4 cup. The values for adhesion tests # 1 and # 2 reflect the percentage of the top coating-repair material stripped from the original top re-cover. The panels were sorted by a 2 mm retisula and pulled at an angle of 45 with a Scotsh® tape 810 cellophane tape. The value reported for the Apariensia was measured from a panel using an Autospest® instrument. This is a stained glass, they are image distinction and detachment of luck (Ford stash). The biggest numbers are the best. A review of the results in Table 2 indicates that the samples prepared according to the method of the invention, ie, Examples 3 and 5, show an improvement in the general balance of properties.

Claims (16)

1. CLAIMS 1. A method for improving the adhesion of a repair coating to a coated substrate, this method comprises: applying to a substrate at least one coating composition, which includes: (a) a film forming component, which comprises (i) an interlacing somponent, which includes one or more aminoplast resins, and (ii) one or more polymers, which have one or more funsional groups, the suals are reastive with the interlacing somponent, (b) an additive that improves the adhesion, which comprises one or more compounds containing the Sn (IV), (c) a satallizer, to promote the reattachment between the interlacing agent (i) and the polymer (ii), curing this at least one coating composition, for supplying a coated substrate and applying one or more repair coating to the coated substrate.
2. 2. The method of claim 1, wherein the one or more repair coatings are the same as this at least one rollback somposisance.
3. 3. The method of claim 1, wherein the somponent forming pellets comprises (ii) one or more functional carbamate polymers. 4. The method of claim 1, wherein the additive (b) that improves adhesion comprises one or more compounds seleaded from the group consisting of compounds having the formula: (X) n - Sn - (R) m where m , n = 1 to 3, m + n = 4 or 5, X is at least one alkyl group C? R R is a conjugate base of an acid, or
4. (X «)
5. - O Sn - (R1) where q = 0 to 2, r = 1 to 3, r + q = 3 or 4, X 'is selected from X and R' is selected from R. The method of claim 4, wherein the additive (b) is selected from the group consisting of compounds having the formula: (X) n - Sn - (R) m where m, n = 3, m + n = 4 or 5, X is a C1-6 alkyl group and R is a conjugated base of an acid, selected from the group consisting of water, alcohols, carboxylic acids, phosphoric acid, alkyl mono- and di-phosphates, or aryl, alkyl or aryl phosphonates, alkyl or aryl sulfonates, alkyl or aryl sulfates, and mixtures thereof.
6. 6. The method of claim 5, wherein the acid is selected from the group consisting of the asystid acid, substituted sulfonisosides are alkyl, substituted sulphideous acids are aryl, and their mixtures.
7. 7. The method of claim 5, wherein the additive (b) is dibutyl tin diastate.
8. 8. The method of claim 1, wherein the satallizer (s) is an at least partially blocked satalizer.
9. 9. The method of claim 1, wherein said at least one replenishment additionally comprises: (d) an adhesion-promoting component, consisting of: (i) a component containing an epoxy group, and (ii) a component of a monofunctional carboxy group.
10. 10. A rewetting somposission, which has improved adhesion to repair re-surfactants, this re-emergence somposisance consists of: (a) a film forming component, consisting of: (i) an interlacing somponent, which consists of one or more resins of aminoplast, and (ii) one or more polymers, having one or more funsional groups, which are reastives are one or more aminoplast resins, (b) an additive that improves adhesion, which comprises one or more compounds which are the Sn (IV), and (c) a catalyst, to promote a reaction between the one or more aminoplast resins (i) and one or more polymers (ii), this satallizer suffers one or more acidic suspensions, the suals are blocked, at least parsially.
11. 11. The embodiment of claim 10, further comprising: (d) an adhesion promoting component, comprising: (i) a component containing an epoxy group, and (ii) a component of a monofunctional carboxy group.
12. 12. A coated article that is: an article having a substrate with a cured coating thereon, comprising: (a) a component forming a film, which consists of: (i) a interlacing component, which is a or more aminoplast resins, and (ii) one or more polymers, having one or more funsional groups, which are reastives are one or more aminoplast resins, (b) an adhesion enhancing additive, comprising one or more compounds containing the Sn ( IV), and (c) a catalyst, to promote a reaction between the one or more aminoplast resins (i) and one or more polymers (ii), this catalyst comprises one or more acidic compounds, which are blocked, at least partially.
13. 13. The coated article of claim 12, further comprising a repair coating, aplimated to at least a portion of the cured coating.
14. 14. The coated article of the claim 12, which further comprises: (d) a component that promotes adhesion, which consists of: (i) a somponent which is an epoxy group, and (ii) a somponent of a monofunctional sarboxi group1.
15. 15. The re-covered article of the reivindisasión 13, in which the re-surfaced re-surfacing re-surfacing minus one portion of the removed re-surfacing is the same as this at least one coating composition.
16. 16. A method for improving the adhesion of a repair coating to a coated substrate, this method comprises: aplying to a substrate at least one rewinding somposisance, which includes: (a) a component forming a film, which consists of: (i) ) one or more aminoplast resins, and (ii) one or more polymers, having one or more funsional groups, which are reactive are one or more aminoplast resins, (b) an adhesion enhancing additive, which is one or more more somatic having the Sn (IV), and (s) a satallizer, to promote a reaction between the one or more aminoplast resins (i) and one or more polymers (ii), this satallizer comprises one or more acidic compounds, which are blocked, at least partially, and cure this at least one coating composition, to supply a re-coated substrate, and apply one or more repair coatings to the coated substrate.