MXPA99001737A - Cationic electrocoating compositions, method of making, and use - Google Patents

Abstract

An electrodepositable composition that has:(A) an active hydrogen-containing cationic resin, electrodepositable on a cathode, having:(1) a polyepoxide;(2) an oxygen-substituted diamine compound having formula (I) where n is an integer from 2 to 4;and where R1 or R2 are the same or different and either one or both contain at least one oxygen and are alkyl, cycloalkyl, substituted alkyl, or substituted cycloalkyl having from 1 to 6 carbon atoms, or R1 and R2 are alkanol groups having from 2 to 6 carbon atoms, or R1, R2, and the N atom form a cyclic group which is substituted or unsubstituted such as morpholine and 1-(3-aminopropyl)imidazole;and (B) at least partially blocked isocyanate or polyisocyanate curing agent. The diamine compound of formula (I) can be used alone or in conjunction with one or more secondary amines, nonhydroxy group containing amines and/or amines with ring structures. Optionally, the polyepoxide can be chain extended with active hydrogen-containing compounds other than polyoxyalkylene polyamines. Also provided is a method of producing an active hydrogen-containing cationic resin composition, electrodepositable on a cathode, comprised of:(a) mixing together in a suitable reaction vessel a polyepoxide, or the precursors of the polyepoxide, a polycarboxylic acid, a blocked isocyanate curing agent;(b) adding to the mixture of (a) a base catalyst and the diamine compound of formula (I);(c) polymerizing the mixture of (b) to form a resinous composition;and (d) neutralizing the resinous composition of (c) by adding the resinous composition to a dilute mixture of acid and water to form an aqueous dispersed electrodepositable cationic resin composition.

Description

CATIONIC COMPOSITIONS OF ELECTROSTRIDING, METHOD OF PREPARATION AND USE The present invention relates to cationic electrocoating compositions, to the method of preparing these compositions and to their use in electrodeposition. More specifically, this invention relates to lead-free cationic electro-coating compositions or free of any added lead. 'Electrodeposition is a coating application method that involves the deposition of a film-forming composition under the influence of an applied electrical potential. Electrodeposition has become increasingly important in the coating industry, since, compared to non-electrophoretic coating media, electrodeposition offers superior paint utilization, remarkable corrosion protection and low environmental contamination. Initially, electrodeposition was performed by serving the workpiece that was being coated as an anode. This was referred to in a familiar way as "anionic electrodeposition". However, in 1972, cationic electrodeposition was introduced commercially. Since then, cationic electrodeposition has gained 'firmly in popularity and, today, is by far the most prevalent method of electrodeposition. Worldwide, a majority of produced motor vehicles receive a primer coating by cationic electrodeposition. Other areas of application are the primer coating and the final coating of a layer of accessories for automobiles, machinery of farms, domestic and electrical appliances, steel furniture and various structural components. Recent environmental laws have required the formulation of cationic electrodeposition coatings that do not contain heavy metals, such as lead. Some problems that can be encountered with these new compositions include lower performance characteristics, such as lower corrosion resistance, chipping resistance, throwing power and curing response, and lower electrodeposition coating bath pH. Said low pH of the bath can cause problems of corrosivity with the tank, the pipes and the electrodes of the electrodeposition or electrorecovery system. A composition that is intentionally added lead-free but meets the requirements for corrosion resistance, chipping resistance, throwing power, curing response and pH 'of existing electrodepositable compositions containing lead is needed. A series of electrodepositable compositions based on the chemistry of epoxy amines usually require the presence of lead to achieve their performance characteristics. This lead is typically added with the pigments and / or through the use of lead silicate. The first cationic electrodepositable compositions used resins containing amine salt groups or resins containing onium salt groups as a binder; see, for example, US Pat. 3,454,482 to Spoor et al. and U.S. Pat. 3,839,252 to Bosso et al. These compositions required the use of lead to achieve adequate performance characteristics. U.S. Pat. No. 4,192,929 to Wingfield 'describes the use of a secondary amine, which is mostly hydroxyamine, to make a resin containing amine groups in a corrosion resistant electrodepositable primer. This primer also uses crosslinking agents of amine and aldehyde resins to cure the electrodeposited primer. The US Patents 4,182,831 and 4,225,479 to Hicks teach the use of a mixture of primary amines having an aliphatic monoamine and an aliphatic diamine in a resinous cationic epoxide compound. The diamine has a primary amine group and a tertiary amine group. U.S. Pat. 5,034,434 to Beresford et al. teaches the use of a primary monoamine containing a tertiary amino group as a partial substitution of a polyoxyalkylene polyamine, which reacts with a secondary amine, a polyepoxide and a monoepoxide in a cationic resin useful in electrodepositable coating compositions. The compositions described by Beresford et al. they are rich in polyoxyalkylene polyamines and, as indicated in Examples 12 and 14 of Beresford et al., lead silicate is added to the pigment paste. Beresford et al. show that a reduction in the polyoxyalkylenepolyamine ratio can be achieved by replacing some of this with a primary monoamine with reactive hydrogen atoms which react with the epoxide group. Said primary monoamine may also contain a tertiary amino group in its structure, such as dimethylaminopropylamine, diethylaminopropylamine, N-aminopropyldiethanolamine or N-aminopro-morpholine. Unfortunately for the electrodepositable coating compositions indicated above, each has one or more components that can adversely affect the performance characteristics of an electrodepositable coating composition. For example, polyoxyalkylene polyamines, such as those used in the Beresford et al. They result in poor corrosion resistance and can often interfere with chipping resistance, throwing power and intercoat adhesion of electrodeposition coatings. In addition, the presence of alkylamines in an all-aliphatic amine system for the amine reactant for the epoxy may present difficulties in obtaining non-gelled compositions for use in electrodeposition. Additionally, the alkylamines disclosed by Hicks may interfere with the chipping resistance of typical electrodeposited coatings. In addition, the crosslinking agents of amine and aldehyde resins can result in a poorer cure response and corrosion resistance for electrodeposited coatings. In the electrodepositable coating compositions with added lead, the possible adverse effects of these various materials could be tolerated due to the benefits associated with the presence of lead. However, in the most attractive electrodepositable coating compositions, with reduced lead or lead-free, the effects of these various components can be problematic to achieve performance characteristics such as those of the added lead compositions. It is an object of the present invention to provide a cationic electrocoating composition which, without the addition of lead or with a reduced level of lead, has better and consistent resistance to chipping, throwing power and pH control, with a good response to Cured and corrosion resistance. SUMMARY OF THE INVENTION According to the present invention, there is provided an electrodepositable cationic composition having: (A) a cationic resin containing ungelled active hydrogen, electrodepositable on a cathode, having: (1) a polyepoxide, (2) an oxygen-substituted diamine compound having the following formula: R1 / NH2- (CH2) nN Formula I \ R2 where n is an integer from 2 to 4 and where R1 or R2 are the same or different and any of them, or both contain at least one oxygen and are alkyl, cycloalkyl, substituted alkyl or substituted cycloalkyl of 1 to 6 carbon atoms, or R1 and R2 are alkanol groups of 2 to 6 carbon atoms, or R1, R2 and the N atom of the Tertiary amine group form a cyclic group which is substituted or unsubstituted, such as morpholine and 1- (3-aminopropyl) imidazole, and (B) an isocyanate curing agent or at least partially blocked polyisocyanate. In other words, reference can be made to the amine compound of Formula I as an alkylene diamine with a primary amine group and a tertiary amine group, wherein the tertiary amine has two alkyl groups or a cyclic alkyl group, wherein said groups have oxygen substitution, such as alkylene diamine containing n, n-oxygen-substituted alkyl. From now on, this amine compound is referred to as "oxygen-substituted diamine". This oxygen-substituted diamine can be used alone or together with one or more additional amines, including secondary amines, amines that do not contain hydroxy and / or amines with ring structures. However, any combination of amines with the oxygen-substituted diamines is essentially free of polyoxyalkylenepolyamine. In the electrodepositable composition, the polyepoxide can optionally be extended in the chain with materials containing active hydrogen other than polyoxyalkylene polyamines. In addition, an electrodepositable composition may have an aqueous or aqueous and organic solvent vehicle. Said electrodepositable composition has a non-gelled reaction product of the polyepoxide and the amine of Formula I, with or without secondary amines and / or amines that do not contain hydroxyl and / or amines with a ring structure, which can be referred to as "adduct" resinous epoxide and amine. " In addition, the "electrodepositable cationic resin composition containing active hydrogen", with or without the isocyanate or polyisocyanate curing agent, can be at least partially neutralized with acid to achieve a neutralized aqueous cationic electrodepositable resin composition, which can be used as a composition. Electrodepositable aqueous. In addition, additional materials, such as pigments and modifying materials, can be used in the electrodepositable composition. Also provided, as another aspect of the invention, is a method of producing a cationic resin composition containing ungelled active hydrogen, electrodepositable on a cathode, consisting of (a) mixing together in a suitable reaction vessel a polyepoxide, or precursors of the polyepoxide, optionally a polycarboxylic acid and an isocyanate curing agent or at least partially blocked polyisocyanate; (b) adding to the mixture of (a) a basic catalyst and the amine compound of Formula I described above; (c) polymerizing the mixture of (b) to form a resinous composition, and (d) neutralizing the resinous composition of (c) by adding the resinous composition to a diluted mixture of acid and water to form an aqueous dispersible cationic electrodepositable resin composition. . DETAILED DESCRIPTION OF THE INVENTION Surprisingly, these amine compounds represented by Formula I, which are monomeric, when reacted with the polyepoxide and formulated in the electrodepositable cationic resin composition containing ungelled active hydrogen and possibly combined with other possible materials, give rise to an aqueous dispersed electrodepositable composition with an appropriate cure without addition of lead to the coating. The invention provides better curing, preferably even in the absence of lead, which can normally contribute to curing. The elimination of lead addition to the coating composition of the present invention makes the coating more environmentally desirable. The oxygen-substituted diamine of Formula I, when used alone as the sole type of amine reactant for the polyepoxide, to form the resinous epoxide and amine adduct, is generally used in at least that amount sufficient to allow the cationic resin composition electrodepositable that contains ungelled active hydrogen and, preferably, the cationic electrodepositable composition, is transportable to the cathode when it is solubilized in acid. Suitable oxygen-substituted diamines include dihydroxyalkylaminoalkylamine, such as aminopropyldiethanolamine and / or aminopropylmorpholine and / or N- (2-aminoethyl) morpholine. Aminopropyldiethanolamine is preferred. It is believed, without limiting the invention, that these oxygen-substituted diamines react with the polyepoxide in such a way that the oxygen atoms hang as part of the amine moiety of the amine-epoxide adduct. Optionally, the cationic electrodepositable composition may additionally contain one or more secondary amines, wherein up to 70 percent of the NH equivalents of the reactants for producing the electrodepositable cationic resin composition containing active hydrogen of the electrodepositable composition are supplied by the secondary amine. and from 30 to 100 percent of the NH equivalents are supplied by the oxygen-substituted diamine. Preferably, from 20 to 50 percent of the NH equivalents are supplied by the secondary amine and from 50 to 80 percent of the NH equivalents are supplied by the oxygen-substituted diamine. More preferably, the secondary amine is present in an amount that provides 20 to 30 percent of the NH equivalents of the reactants and 70 to 80 percent of the NH equivalents of the reactants are supplied by the compound diamine oxygen -substituted. Some non-limiting examples of secondary amines include dialkanolamines, alkylalkanolamines and arylalkanelamines containing from 2 to 18 carbon atoms in the alkanol, alkyl and aryl chains. Specific examples include N-ethylethanolamine, N-methylethanolamine, diethanolamine, N-phenylethanolamine and diisopropanolamine. Amines not containing hydroxyl groups, such as mixed diamines and alkylaryl amines can also be used and substituted amines can also be used, wherein the substituents are other than hydroxyl and wherein the substituents do not detrimentally affect the epoxy-amine reaction. Specific examples of these amines are methylethylamine, diethylamine, diproylamine, dibutyl amine, dicocoamine, diphenylamine, N-methylaniline, diisopropylamine, methylphenylamine and dicyclohexylamine. In addition, amines with ring structures can be used, such as morpholine, piperidine, N-methylpiperazine and N-hydroxyethylpi-perazine. further, ketimines, such as diethylenetriaminadicetimine, can be used. Any of them, or a combination of these amines, can replace a part of the secondary amine, or all, used in combination with the oxygen-substituted diamine. More preferably, the oxygen-substituted diamine, on a weight basis, is the predominant amine in any combination or mixture with the above-mentioned secondary amines and / or amines not containing hydroxy and / or other amines. In addition, preferably, polyoxyalkylenepolyamines and primary alkylmonoamines are absent from any of these combinations or mixtures of amines. The polyepoxides used in the practice of the present invention can be saturated or unsaturated, cyclic or acyclic, aliphatic, alicyclic, aromatic or heterocyclic, as is known to those skilled in the art. In addition, the polyepoxides may contain substituents such as halogen, hydroxyl and ether groups. Examples of polyepoxides are those polymers having a 1,2-epoxy equivalence greater than one and, preferably, about two, ie, polyepoxides having, on a medium basis, two epoxy groups per molecule, as is well known in the art. . Preferred polyepoxides are polyglycidyl ethers of cyclic polyols. Particularly preferred are the polyglycidyl ethers of polyhydric phenols, such as bisphenol A. These polyepoxides can be produced by, or have precursors of, the etherification of polyhydric phenols with epihalohydrin or dihalohydrin, such as epichlorohydrin or dichlorhydrin, in the presence of alkali. Examples of polyhydric phenols are 2, 2-bis (4-hydroxyphenyl) propane, 1, 1-bis (4-hydroxyphenyl) ethane, 2-methyl-1, 1-bis (4-hydroxyphenyl) propane, 2, 2-bis. (4-hydroxy-3-butylter-cyanophenyl) propane, bis (2-hydroxynaphthyl) methane, 1,5-dihydroxy-3-naphthalene or the like. In addition to the polyhydric phenols, other cyclic polyols can be used in the preparation of the polyglycidyl ethers of cyclic polyol derivatives. Examples of other cyclic polyols are alicyclic polyols, particularly cycloaliphatic polyols, such as 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,2-bis (hydroxymethyl) cyclohexane, 1,3-bis (hydroxymethyl) cyclohexane. and hydrogenated bisphenol A. In general, other examples of polyepoxide polymers with molecular weights of about 200 to 2000 are shown in US Pat. 4,711,917 (columns 5-8), 4,031,050 (columns 3-5) and 3,922,253 (columns 1-2). The preferred polyepoxides have number average molecular weights ranging from 340 to 2000. In general, the epoxide equivalent weight of the polyepoxide will vary between 100 and 2000 and, preferably, between 180 and 500. Acrylic polymers containing epoxy groups can also be used, such as those of U.S. Pat. 4,001,156 in columns 3-6, but they are not preferred. The term "epoxy equivalent weight", as used in the present description and in the claims at the end thereof, refers to the reciprocal of the equivalents of the epoxy groups contained per gram of an epoxy compound and can be measured by any known method of determination. Examples of these include infrared spectroscopy (IR) or the titration method of HCl-pyridine, through reaction with an excess of HCl in pyridine and titration of the remaining HCl with sodium methoxide, or titration in chloroform with perchloric acid in the presence of an excess of tetra-ethylammonium bromide and glacial acetic acid with a crystal violet stirrer (hexamethylpararosaniline chloride, or by titration of a sample of the reaction product with tetrabutylammonium iodide and perchloric acid). Long chain polyepoxide polymers can also be used, and are preferred. In general, chain extension can be done by reacting together a polyepoxide and a material containing polyhydroxyl groups, selected from materials containing alcoholic hydroxyl groups and materials containing phenolic hydroxyl groups to prolong the chain or increase the molecular weight of the polyepoxide. An extended chain polyepoxide can be prepared by any method known to those skilled in the art and is typically prepared by reacting the polyepoxide and the polyhydroxyl group containing material together, either net or in the presence of an inert organic solvent, such as a ketone, including methyl isobutyl ketone and methyl amyl ketone; aromatics, such as toluene and xylene, and glycol ethers, such as diethylene glycol dimethyl ether. The reaction is usually carried out at a temperature of 80 ° C to 160 ° C, for 30 to 180 minutes, until a resinous reaction product containing epoxy groups is obtained. The equivalent ratio of the reagents, i.e., epoxy: polyhydroxyl group containing material, is typically from 1: 0.75 to 1: 2. These materials and the reactions for producing them are described more fully in U.S. Pat. 4,148,772 (columns 2-6) and 4,468,307 (columns 2-4) and in Canadian Patent 1,179,433, all of which are incorporated herein by reference for their teachings regarding the chain extension of polyepoxides. Examples of materials containing polyhydroxyl groups used to prolong the chain or increase the molecular weight of the polyepoxide (ie, through the hydroxyl-epoxy reaction) include materials that contain. alcoholic hydroxyl groups and materials containing phenolic hydroxyl groups. Examples of materials containing alcoholic hydroxyl groups are simple polyols, such as neopentyl glycol; polyester polyols, such as those described in US Pat. 4,148,772; polyether polyols, such as those described in US Pat. No. 4,468,307, and the urethane diols, such as those described in US Pat. 4,931,157, all of which are incorporated herein by reference to these teachings. Examples of materials containing phenolic hydroxyl groups are polyhydric phenols, such as Bisphenol A, phloroglucinol, catechol and resorcinol. Mixtures of materials containing alcoholic hydroxyl groups and materials containing phenolic hydroxyl groups can also be used. Bisphenol A is preferred. In addition, the chain extension of the polyepoxides can optionally, but preferably, be made with a polycarboxylic acid material, preferably a dicarboxylic acid. Useful dicarboxylic acids include acids having the general formula: HOOC-R-COOH, where R is a divalent moiety substantially unreactive with the polyepoxide. R can be a straight-chain or branched alkylene or alkylidene radical which normally contains from 2 to 42 carbon atoms. Examples of suitable dicarboxylic acids include adipic acid, 3, 3-dimethylpentanedioic acid, benzenedicarboxylic acid, phenylenediethenic acid, naphthalenedicarboxylic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid. It should be understood that, as dicarboxylic acids of the above general formula, where R is a residue of less than 4 carbon atoms, there may be included, for example, oxalic acid, malonic acid, succinic acid and glutaric acid, but these acids are less preferred. Additional suitable dicarboxylic acids include substantially saturated acyclic dimeric acyclic acids, formed by the dimerization reaction of fatty acids having from 4 to 22 carbon atoms and a terminal carboxyl group (dimeric acids having from 8 to 44 carbon atoms being formed ). Dimeric acids are well known in the art and are marketed by Eryth Industries, Inc. under the trademark EMPOL. The dicarboxylic acids can be formed as reaction products of anhydrides and diols or diamines under reaction conditions and techniques known to those skilled in the art for particular reagents. The most preferred dicarboxylic acids are formed by the reaction product of a diol and an anhydride. The diols may include polytetramethylene glycols, polycaprolactones, polypropylene glycols and polyethylene glycols. Preferably, the diol is the reaction product of bisphenol A and ethylene oxide. Suitable anhydrides include maleic, italic, hexahydrophthalic and tetrahydrophthalic. Preferably, the anhydride is hexahydrophthalic anhydride. Additionally, dicarboxylic acids formed by the reaction of an anhydride and a diamine can be used. Dicarboxylic acids formed by the reaction of a polyoxyalkylene diamine can be used, such as polyoxypropylene diamine, marketed by Huntsman Chemical Company under the trademark JEFFAMINE, with an anhydride as indicated above. Preferably, the anhydride is hexahydrophthalic anhydride and the diamine is JEFFAMINE D-400 or D-2000. Typically, the amount of dicarboxylic acid used to prolong the polyepoxide chain is sufficient to obtain from 0.05 to 0.6, preferably from 0.2 to 0.4, acid groups per epoxide group. This reaction is usually carried out at a temperature between 80 ° C and 175 ° C. The amount of the entire amine reacted with the polyepoxide, as indicated above for the oxygen-substituted diamine, is at least that amount which is sufficient to cause the electrodepositable cationic resin composition containing active hydrogen to be cationic in character. In some cases, substantially all of the epoxy groups in the resin can react with an amine. However, an excess of epoxy groups may remain which hydrolyze upon contact with water to form hydroxyl groups. In general, the electrodepositable cationic resin should contain from 0.1 to 3.0, preferably from 0.3 to 1.0 milliequivalents of cationic groups per gram of resin solids (including the isocyanate curing agent). The electrodepositable composition of the present invention also contains a blocked or capped isocyanate or polyisocyanate curing agent. Preferably, the electrodepositable cationic resin composition containing active hydrogen has the blocked or capped isocyanate or polyisocyanate curing agent. The curing agent may be fully capped, substantially free of isocyanate groups, or may be partially capped and reacted with the resin backbone of the electrodepositable cationic resin containing active hydrogen, as described in US Pat. 3,984,299. The isocyanate curing agent can be an aliphatic or aromatic diisocyanate or polyisocyanate or a mixture of the two. Diisocyanates are preferred, although higher polyisocyanates can be used in place of, or in combination with, diisocyanates. Examples of suitable aliphatic diisocyanates are the straight chain aliphatic diisocyanates, such as 1,4-tetramethylene diisocyanate and 1,6-hexamethylene diisocyanate. In addition, cycloaliphatic diisocyanates can be employed. Examples include isophorone diisocyanate and 4,4'-methylenebis (cyclohexyl isocyanate). Examples of suitable aromatic diisocyanates are p-phenylene diisocyanate, diphenylmethane-4,4'-diisocyanate and 2,4- or 2,6-toluene diisocyanate. Examples of suitable higher polyisocyanates are triphenylmethane-4,4 ', 4"-triisocyanate, 1,4-benzene triisocyanate, polymethylene polyphenyl polyisocyanate and methylene polyphenyl polyisocyanate, and isocyanate prepolymers, such as reaction products, can also be used. of polyisocyanates with polyols, such as neopentyl glycol and trimethylolpropane, and with polymeric polyols, such as polycaprolactone diols and triols (equivalent ratio NCO / OH greater than one) A mixture containing diphenylmethane-4, 4 is preferred. 'Polymethylene polyphenyl diisocyanate and polyisocyanate Preferred capped isocyanates or curative or crosslinking agents of organic polyisocyanates are those in which the isocyanate groups have reacted with a compound, such that the resulting capped isocyanate is stable to the active hydrogens ambient temperature, but reactive with active hydrogens at elevated temperatures, usually between 80 ° C and 200 ° C. Any suitable aliphatic, cycloaliphatic or aromatic phenolic monoalcoholic and phenolic compound can be used as a quenching agent according to the present invention, such as, for example, lower aliphatic alcohols containing from 1 to 4 carbon atoms, such as methanol, ethanol and alcohol n-butyl; cycloaliphatic alcohols, such as cyclohexanol; aromatic alkyl alcohols, such as phenylcarbinol and methylphenylcarbinol; phenolic compounds, such as phenol itself, substituted phenols in which the substituents have no adverse effects on the coating operations. Examples include cresol and nitrophenol. Also useful are glycol ethers, such as ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, propylene glycol monomethyl ether, diethylene glycol monobutyl ether and dipropylene glycol monobutyl ether, and glycols such as those described in US Pat. 4,435,559 and 5,250,164 to Valko et al., Including ethylene glycol, propylene glycol and butylene glycol. Additional fining agents include oximes, such as methyl ethyl ketoxime, acetone oxime and cyclohexanone oxime and lactams such as epsilon-caprolactam. Preferred finishing agents are low molecular weight fillers, such as ethylene glycol monobutyl ether and propylene glycol. Normally, a sufficient amount of the at least partially blocked polyisocyanate is present in the electrodepositable composition, preferably in the electrodepositable cationic resin composition containing active hydrogen, such that there are from 0.1 to 1.2 isocyanate groups capped by each active hydrogen, that is, hydroxyl, primary and secondary amino. When measured as a percentage by weight of the resin solids, the blocked isocyanate is present at 5 to 60 percent, preferably 25 to 50 percent. The electrodepositable resin composition containing partially neutralized active hydrogen with or without at least partially blocked isocyanate curing agent can be prepared using any technique known in the art. First, the polyepoxide is typically prepared by chain extension with bisphenol A or other active hydrogen compounds. Second, the polyepoxide is defunctionalized by reaction with the oxygen-substituted diamine, with or without any of the additional amines indicated above, through the reaction with the polyepoxide by mixing the amine and the polyepoxide. The amine can be added to the polyepoxide or vice versa. The reaction can be carried out neat or in the presence of a suitable solvent, such as methyl isobutyl ketone, xylene or 1-methoxy-2-propanol. The reaction is generally exothermic at a temperature in the range of 120 ° C to 150 ° C and it may be desired to cool. However, the reaction mixture can be heated to a moderate temperature, i.e. from 50 ° C to 150 ° C. The resulting reaction product is then dispersed in a mixture of water and acid. In addition, with the addition of the amine, the capped or partially capped isocyanate curing agent can be, and suitably is, added. By "ungelled" is meant that the resin is substantially free of crosslinking and, prior to the formation of cationic salt groups, the resin has a measurable intrinsic viscosity when dissolved in a suitable solvent. In contrast, a gelled resin having an essentially infinite molecular weight would have an intrinsic viscosity too high to be measured. The present invention employs a new method for preparing the electrodepositable resin composition containing active hydrogen with the isocyanate curing agent. The new method consists of mixing together, in a suitable reaction vessel, polyepoxide, diphenol, an at least partially capped isocyanate curing agent, basic catalyst, oxygen-substituted diamine and, optionally, but preferably, one or more secondary amines. and / or other additional amines mentioned above and then reacting the mixture in one step. Optionally, a polycarboxylic acid, preferably a dicarboxylic acid, may also be added to the mixture. It should be noted that the amines and the basic catalyst must be added to the mixture after the other components have been mixed together. Suitable basic catalysts include triphenylphosphine, ethyltriphenylphosphonium iodide, tetrabutylphosphonium iodide and tertiary amines, such as benzyldimethylamine, dimethylaminociclohexane, triethylamine, N-methylimidazole of tetrabutylammonium hydroxide. The amount of the basic catalyst may be an amount similar to that of U.S. Pat. 5,260,354 to Kaylo et al. as effective catalytic amount. In general, said amount is a small amount, ranging from 0.005 to 0.15 percent by weight of the reactants. Typically, the reaction is carried out at a temperature of 80 ° C to 140 ° C, for 1 to 6 hours, in an inert atmosphere. The resulting reaction product is then neutralized by adding the reaction product to a diluted mixture of and water to form a stable dispersion. The dispersions for any of the aforementioned methods are achieved by this neutralization of all or part of the amino groups with , as is known to those skilled in the art. Examples of suitable s include organic and inorganic s, such as formic , acetic , lactic , phosphoric , sulfamic and carbonic . The preferred is sulfamic . The degree of neutralization will depend on the specific product involved. It is only necessary to use enough to disperse the product in water. Typically, the amount of used will be sufficient to obtain at least 30 percent of the total theoretical neutralization. An excess of beyond that required for 100 percent of the total theoretical neutralization can also be used. It is desirable to electrodeposit the coating compositions of this invention from a solution having a pH of between 3 and 9, preferably between 5 and 7. The neutralization should produce a stable dispersion, which means one that does not settle or that is easily redispersible if some sedimentation occurs. The electrodepositable composition of the present invention also usually contains a pigment that is incorporated into the composition in paste form. The pigment paste is prepared by grinding or dispersing a pigment in a grinding vehicle and optional ingredients, such as wetting agents, surfactants and defoamers. The grinding is normally performed by the use of ball mills, Cowles dissolvers or continuous grinders, until the pigment has been reduced to the desired size and has been humidified and dispersed by the grinding vehicle. After grinding, the particle size of the pigment should be as small as practical; in general, a Hegman crushing gauge rating of 6 to 8 is usually employed. Suitable pigment grinding vehicles can be selected from those known in the art. Non-limiting examples of pigments which can be employed in the practice of the invention include titanium dioxide, carbon black, iron oxide, clay, talc, silica, strontium chromate, coal dust, barium sulfate and Phthalocyanine Pigments with high surface areas and oil absorbances should be used judiciously, as they can have an undesirable effect on coalescence and flow. The pigment content of the dispersion is usually expressed as the ratio of pigment to resin. In the practice of the invention, the pigment to resin ratio is usually in the range of 0.05 to 1: 1. In addition to the components described above, the present composition may also include various additives such as: surfactants, wetting agents, catalysts, film forming additives, opacifying products, defoamers and additives such as those in US Pat. 4,423,166 to increase the flow and appearance of the composition, cationic microgels such as those in US Pat. 5,096,556 and additives for pH control. The latter additives may be at least partially neutralized polyepoxide-amine adducts, with a pH above sufficient to adjust the pH of the bath to the aforementioned desired range, if necessary. Examples of surfactants and wetting agents include alkylimidazolines, such as those obtainable from Geigy Industrial Chemicals such as GEIGY AMINE C, and acetylenic alcohols, which can be obtained from Air Products and Chemicals as SURFYNOL. Examples of defoamers are FOAM KILL 63, hydrocarbon oil containing inert diatomaceous earth, which can be obtained from Crucible Chemical. Examples of antiaking agents are the polyoxyalkylene-polyamine reaction products, such as those described in US Pat. 4,432,850. These eventual ingredients, when present, may constitute up to 30, usually from 1 to 20, pnt by weight of the resin solids. Curing catalysts, such as tin catalysts, may be present in the composition. Some examples include dibutyltin dilaurate and dibutyltin oxide. Optionally, a cocatalyst can be used, such as water-immiscible acids and those of International Publication No. W096 / 12771 and gomorresin. When used, the catalysts are typically present in amounts of from 0.05 to 5 weight pnt based on the weight of the resin solids. The electrodepositable coating compositions of the present invention are dispersed in aqueous medium. The term "dispersion", as used in the context of the present invention, is believed to be a two-phase translucent or opaque aqueous resinous system, in which the resin is in the dispersed phase and the water in the phase keep going. The diameter of the average particle size of the resinous phase is 0.1 to 10, preferably less than 5 microns. The concentration of the resinous products in the aqueous medium is not, in general, critical, but, ordinarily, the largest portion of the aqueous dispersion is water. The aqueous dispersion typically contains from 3 to 75, typically from 5 to 50, pnt by weight of the resin solids. The aqueous resin concentrates can still be diluted with water when preparing the electrodeposition baths. Fully diluted electrodeposition baths generally have resin solids contents of 3 to 25 weight pnt. In addition to water, the aqueous medium may contain a coalescing solvent. Useful coalescing solvents include hydrocarbons, alcohols, esters, ethers and ketones. Preferred coalescent solvents include alcohols, polyols, ethers and ketones. Specific coalescing solvents include isopropanol, butanol, 2-ethylhexanol, isophorone, 4-methoxy-2-pentanone, ethylene and propylene glycol and the monoethyl, monobutyl and monohexyl ethers of ethylene glycol. The amount of coalescing solvent is not unduly critical to performance, but is minimized for environmental reasons and is generally present in an amount of up to 5 weight percent, preferably from 0.05 to 5 weight percent, in based on the total weight of the aqueous medium. In the electrodeposition process, the electrodepositable composition is contacted with an electrically conductive anode and an electrically conductive cathode. By passing the electric current between the anode and the cathode while in contact with the aqueous dispersion, an adherent film of the coating composition will be deposited in a substantially continuous manner on the cathode. The conditions under which electrodeposition is carried out are well known in the art. Electrodeposition is normally carried out at a constant voltage. The applied voltage will vary greatly and may be, for example, only 2 volts or up to several thousand volts, although typically between 50 volts and 500 volts are used. The current density is usually between 1.0 amps and 15 amps per square foot (10.8 to 161.5 amps per square meter) and tends to decrease rapidly during electrodeposition, indicating the formation of a self-insulating continuous film. Any electroconductive substrate, especially metal, such as steel, zinc, aluminum, copper, magnesium or the like, can be electrocoated with the coating compositions of the present invention. However, the invention is particularly desirable for the coating of steel substrates, due to the remarkable resistance to corrosion that it gives to the substrate. Although it is conventional to pretreat the steel substrate with a phosphate conversion coating, followed by a washing with chromic acid or non-chromic acid prior to electrodeposition, the electrodeposition process of the present invention can be used with steel substrates to which There has not been a chrome wash and it still provides a remarkable resistance to corrosion. After the deposition, the coating is cured at elevated temperatures by any convenient method, such as baking in ovens. The curing temperature will typically be in the range of 120 ° C to 250 ° C, preferably 120 ° C to 190 ° C, for any time between 10 and 60 minutes. The thickness of the resulting film will typically vary from 10 to 50 microns. The invention will now be described with reference to the following examples, which are presented for illustrative purposes only and are not intended to limit the scope of the invention.

EXAMPLE A PART I (Preparation of a dicarboxylic acid adduct) A dicarboxylic acid adduct was prepared by the following procedure. To a reactor, equipped with a stirrer, a nitrogen inlet and a condenser, 160.8 parts of hexahydrophthalic anhydride, 328.7 parts of a diol made from bisphenol A (1 mole) and ethylene oxide (9) were added. moles) and 0.5 parts of triethylamine. The reaction mixture produced an exotherm and was maintained at a temperature of 90 ° C to 100 ° C until the anhydride peaks disappeared in the infrared spectrum. The dicarboxylic acid adduct had an acid number of 120. PART II (Preparation of a blocked isocyanate crosslinker) A blocked isocyanate crosslinker was prepared by the following method. To a reactor, equipped with a stirrer, a nitrogen inlet, a condenser and an addition orifice, 115.9 parts of butyl CELLOSOLVE1 and 74.7 parts of propylene glycol were added. The mixture was heated to a temperature of 50 ° C to 55 ° C and then 259.4 parts of PAPI 29402 were added over a period of 2.5 to 3.0 hours. The exotherm was maintained below 100 ° C during the addition and the reaction was maintained for 1.0 hour at 90 ° C after completion of the addition. The infrared spectrum showed a complete reaction of the isocyanate group (disappearance of the 2270 reciprocal centimeters) (band of cm "1) Then methyl isobutyl ketone was added, 50 parts, and the reactor crosslinker was discharged 1 Ethylene glycol monobutyl ether , from Union Carbide Chemicals and Plastics Co., Inc. 2 Polymeric methylenediphenyl diisocyanate, having an isocyanate functionality of 2, 3, from Dow Chemical Company. PART III (Preparation of an Active Electrodepositable Resin Composition of the Present Invention) An electrodepositable resin composition containing active hydrogen of the present invention, which contained aminopropyldiethanolamine, was prepared by the following method. reactor equipped with a stirrer, a nitrogen inlet and a condenser components A to F of the following Table 1. The contents of the reactor were brought to 80 ° c and articles G to l were added in. An immediate exotherm was produced and left that the temperature rose to 120 ° C to 130 ° C. The reaction mixture was maintained at 120 ° C. for 2.0 hours A sample taken after 1.5 hours had an acid number equal to zero and an equint weight of epoxide of more than 20,000, which indicates the complete reaction of the acid and the epoxide.The contents of the reactor were dispersed in a mixture of the components J to K. Afterwards the r the dispersion, component L was added. The dispersion was then purified in vacuo to azeotropically remove the methyl isobutyl ketone used as the solvent and then the M component was added. The product was an electrodepositable aqueous dispersion having a solids content of 40.3. percent by weight, with a particle size of 821 Angstroms and a Brookfield viscosity of 70 centipoise.

TABLE 1 Component Parts by weight A. EPON 8801 85.7 B. Dicarboxylic acid of Example A, 54.8 Part I C. Bisphenol A 28.0 D. D. Crosslinker of Example A, Part II 128.9 E. Tetronic 150R12 0 , 08 F. Methyl isobutyl ketone 8.0 G. Benzyldimethylamine 0.2 H. Aminopropyldiethanolamine 13.9 I. Dietanolamine 4.5 J Sulfolamic acid 6.7 K. Deionized water 466.5 L. Gomorresin3 1.5 M. Rhodameen C-54 3.0 1 Polyglycidyl ether of bisphenol A, from Shell Chemical Co. 2 A surfactant consisting of an ethylene-propylene oxide adduct of ethylene diamine, which contains a 90:10 ratio of propylene oxide to ethylene oxide and which is finished in propylene oxide, marketed by BASF Corporation. 3 A rosin containing 10% neutral materials and 90% rosin acid, of which 90% is abietic acid (and isomers) and 10% is a mixture of dihydroabietic acid and dehydroabietic acid, marketed by Colyer Chemical Co. 4 A surfactant consisting of pentaethoxylated cocoamine, marketed by Rhéne-Poulenc. EXAMPLE B An electrodepositable resin composition containing active hydrogen of the present invention, which contained aminopropylmorpholine, was prepared by a method similar to that of Example A, Part III. Components A to E of Table 2 were charged to the reactor, the temperature was brought to 80 ° C and then components F to H were added. After the exotherm, the reaction was maintained at 120 ° C for 2, 0 hours . The reaction mixture was then dispersed in a mixture of the components I, J and L and component K was then added. The dispersion was purified in vacuo to obtain an electrodepositable aqueous dispersion with a solids content of 46.5 percent by weight. weight. TABLE 2 Component Parts by weight A. EPON 880 45.1 B. Dicarboxylic acid of Example A, 28.8 Part I C. Bisphenol A 14.7 D. Crosslinker of Example A, Part II 64.2 Component Parts by weight E Tetronic 150R12 0.04 F. Benzyldimethylamine 0.09 G. Aminopropylmorpholine 6.5 H. Dietanolamine 2.4 I. Sulfamic acid 3.3 J. Deionized water 167.6 K. Gomorresin3 0.7 L. Rhodameen C-5 1.4 EC EXAMPLES (COMPARATIVE) Electrodepositable resin compositions containing active hydrogen, which contained dimethylaminopropylamine or diethylaminopropylamine, were prepared by a method similar to that of Example A, Part III, except for the use of a different crosslinker. This blocked isocyanate crosslinker, referred to as "PART IIB", was prepared in a procedure identical to that of PART II of Example A, except for the fact that methyl isobutyl ketone was not used. For each example (CE), components A to F of Table 3 were charged to the reactor, the temperature was brought to 80 ° C and then components G to H were added. After the exotherm, the reaction was maintained at 120 ° C for 2.0 hours. The reaction mixture was then dispersed in a mixture of components I, J and L and component K was then added. The amounts indicated in Table 3 are parts by weight.

TABLE 3 EXAMPLES FJ The following Examples F to J are electrorecoverable resin compositions containing active hydrogen prepared by a method similar to that of Example A (Part III) and B. In these examples, the secondary amine differed from the diethanolamine of Example A (Part III ), which was component I, by substitution with one of the following amines: hydroxyethylpiperazine (HEPIP), N-methylpiperazine (NMPIP), morpholine (MOR) or dicocoamine (DICOCO). These substitutions were made at equal levels of amine equivalents for diethanolamine. For each example (FJ), components A to F of Table 4 were charged to the reactor, the temperature was brought to 80 ° C and then components G to H were added. After the exotherm, the reaction was maintained at 120 ° C for 2.0 hours. The reaction mixture was then dispersed in a mixture of components I, J and L and component K was then added, followed by component M. The amounts indicated in Table 4 are parts by weight.

TABLE 4 ionized% Solids in 37, 8 38, 0 37, 5 28, 1 weight Ü. I-V GEMPLES (custom numbers) The electrodepositable, active hydrogen-containing resin compositions of Examples A through E were used to prepare electrodeposition compositions of the following Examples I to V. Examples I to V illustrate the effect of the change of the tertiary amine slope used in the extension of the epoxy chain of the electrodepositable resin compositions of Examples A to E. Examples III to V are comparative examples. The various amines used in Examples A to E were the oxygen-substituted diamines aminopropyldiethanolamine (APDEA) (Example A) and aminopropylmorpholine (APM) (Example B) and comparative amines, dimethylaminopropylamine (DMAPA) (Examples C and D) and diethylaminopropylamine ( DEAPA) (Example E). A secondary amine, diethanolamine DEA), was also used in Examples A to E. Baths of the cationic electrodepositable composition were prepared in a suitable container for each of Examples I to V by mixing with each other, with stirring, the components of Table 5 in the order indicated. The amounts indicated in Table 5 are parts by weight.

TABLE V 1 An aqueous dispersion of a flow regulator-flexibilizing agent was generally prepared according to US Pat. 4,423,166 for use with the electrodepositable composition. The flow regulator-flexibilizer was prepared from a polyepoxide (EPON 828) and a polyoxyalkylenepolyamine (JEFFAMINE D-2000, Texaco Chemical Co.). The flow regulator-flexibilizer was dispersed in an aqueous medium with the aid of lactic acid and the dispersion had a resin solids content of 35.4 weight percent. 2 A cationic microgel prepared as described generally in Examples A and B of US Pat. No. 5,096,556, with the exceptions that acetic acid was used in place of lactic acid to disperse the soap of Example A, that ethylene glycol butyl ether was used instead of methyl isobutyl ketone as solvent in the buffer of Example A and that EPON 828 solution was added after better purification than before in Example B. The resin had a final solids weight content of 18.3 percent. , 3 An additive for pH control consisting of an epoxy monomer (EPON 880) advanced by Bisphenol A, in the presence of ethyltriphenyl phosphonium iodide catalyst, to an epoxy equivalent weight of about 750. The reaction is stopped with diketimine and then it is dispersed in acetic acid and water. In water, diketimine undergoes hydrolysis, leaving the primary amine exposed, which is basic, giving the additive a pH of about 8. 4 A commercialized pigment paste such as E-6160 by PPG Industries, Inc., which contains a , 7% titanium dioxide, 31.4% aluminum silicate, 12.7% dibutyltin oxide and 2.2% carbon black. Phosphate zinc phosphate panels were electrorevealed with the electrodeposition compositions of Examples I to V, at voltages ranging from 160 to 375, volts, for two minutes, at bath temperatures between 9Q ° F and 95 ° F (between 32 ° C and 35 ° C), they were washed with deionized water and cooked several times. temperatures, as indicated below in Table 6. The bath temperature and coating voltage were selected to produce a final cured film of 0.95 mils (24 microns). The panels were evaluated for curing response, chipping resistance and corrosion. The throwing power for each of the compositions was also determined, with the results shown in the following Table 6.

TABLE 6 1 Stress resistance Stone was measured by gravimetric test (ASTM D-3170 operated with panels cooled to -30 ° C). The panels were initially evaluated on a rating scale from 0 to 10, representing 0 badly chipped panels and 10 representing a very good chipping performance. In the above table, the results are a comparison with similar panels electrocoated with ED5050, a commercial paint containing lead used as a control. The plus sign indicates better performance than the control, while the minus sign indicates worse performance. Corrosion resistance measured by General Motors GM9540-P test method, cyclic corrosion test.

After the preparation, the test panels were treated at 25 ° C and a relative humidity (RH) of 50% for 8 hours, including 4 sprays at 90 minute intervals with a solution containing 0.9% NaCl, 0.1% CaCl2 and 0.25% NaHCO3 in deionized water. The test panels were then subjected to an 8 hour mist, 100% RH at 40 ° C, followed by 8 hours at 60 ° C and less than 20% RH. The complete treatment is repeated the desired number of cycles, 40 cycles for this test. 3 The "throwing power" is defined as the ability of a paint to electrocoat surfaces enclosed in a box-like structure. Boxes of several models have been designed to reproducibly measure this property. Two of these are described below in notes 4 and 5. A box of phosphatized steel panels was constructed, measuring 27.5 x 8.5 x 0.4 cm, open to the paint bath only on the 8.5 x 0.4 cm. After coating this assembly with conditions giving the nominal film thickness of 0.95 mils (24 microns) on the outside of the box, the length of the box over which the coating was deposited from the opening to where the paint stops coating. 5 A box with four cold rolled steel test panels measuring 15 cm long by 7 cm wide and two rubber joints measuring 15 cm long and 58 cm wide and 18 cm thick was built. Three of the four test panels contain a 7 mm hole located 5 cm from the bottom of the panel and 3.5 cm from its side. The rubber joints acted like the sides of the box, while the panel No. 1 formed the front and the panel No. 4 formed the back (panel No. 4 had no hole). The bottom of the box was sealed with 3-inch adhesive tape and the top of the box was open to the atmosphere. The four panels were parallel to each other and were spaced as follows: 10 cm between No. 1 and 2, 22 cm between No. 2 and 3, 10 cm between No. 3 and 4. The surfaces of the panels were referenced as A to H, looking at the surface A, C, E, G in front of the box. The whole assembly was partially submerged in the electrocoat coating bath at a depth of 9 cm, so that the holes in panels 1 to 3 were approximately 4 cm below the surface of the bath and the top of the box remain open to the atmosphere. The four panels were electrically connected to the cathode of a power source and a 15 cm by 7 cm stainless steel anode was placed 15 cm from the surface A. The panels were then coated for 3 minutes at the voltage indicated above. The ejection power for this test was defined as the ratio, given as a percentage, of the thickness of the film measured on the surface G (panel No. 4) to the thickness of the film measured on the surface A (panel No. 1) . 6 A cloth saturated with acetone was firmly rubbed from one part to another through the coating surface cured 100 times for panels baked at 280 ° F (138 ° C), 300 ° F (149 ° C), 310 ° F ( 154 ° C), 320 ° F (160 ° C), 330 ° F (166 ° C) and 340 ° F (171 ° C), each time for 30 minutes. The given result is the minimum baking temperature necessary to produce a film that is not scratched by this treatment. 7 ATM. The thermomechanical analysis was performed on specimens from each of the panels described in note 6 above. A full description of this test is given in the ASTM E1545 test method. The conditions included the use of a hemispherical probe charged to 0, 2 newtons, with a heating rate of 10 ° C per minute. The initial extrapolated softening temperatures observed against the baking temperature were plotted, the curves were adjusted to the data and the minimum baking temperature necessary to reach a softening temperature of 85 ° C was given in the table. The lower minimum baking temperatures given indicate better curing response. 8 The softening temperature described in note 7 above ceases to increase at sufficiently high baking temperatures. The given temperature is the limiting value of the softening temperature. Higher temperatures given indicate better curing response. The data in Table 6 show that the electrodeposition coatings of the present invention, containing amine compounds having oxygen atoms in the pending part of the amine moiety, offer advantages in the curing response (cure at lower temperatures), resistance to chipping and better throwing power. EXAMPLES VI-IX The electrodepositable, active hydrogen-containing resin compositions of Examples F to J were used to make the electrodepositable compositions of the present invention in Examples VI to IX. Examples VI to IX illustrate the use of several secondary amines in the electrodepositable compositions of the present invention. Baths of cationic electrodepositable composition were prepared, in a suitable container, for each of Examples VI to IX by mixing with each other, with stirring, the components of Table 7 in the order indicated. The amounts indicated in Table 7 are parts by weight.

TABLE 7 Phosphate zinc phosphate panels with the electrodeposition coating compositions of Examples VI to IX were electroreveisted at voltages ranging from 160 to 375 volts, for two minutes, at bath temperatures ranging from 90 ° F to 95 ° F. (32 ° C to 35 ° C), washed with deionized water and baked at various temperatures as indicated in Table 8. The bath temperature and coating voltage were selected to produce a cured final film of 0.95. milipulgadas (24 microns). The baths were evaluated in terms of pH. The panels were evaluated for curing response and throwing power. In the following Table 8 the results are shown.

TABLE 8 1 See note 3 of Table 6 above. 2 See note 4 of Table 6 above. 3 See note 5 of Table 6 above. 4 See note 6 of Table 6 above. 5 See note 7 of Table 6 above. 6 See note 8 of Table 6 above. 7 Up to a baking temperature of 340 ° F, a softening temperature of 85 ° C is not reached. Table 8 above shows the results for embodiments of the invention in which the secondary amine was varied. The data shows that an adequate cure was obtained using a variety of secondary amines. Some amines were cured at lower temperatures, but all were acceptable. When dicocoamine was used, a softer film was produced, but the acceptable acetone resistance of this material indicates that the films were cured. It was theorized that the softer films produced with cocoamine may be a result of the long fatty acid chain of the dicocoamine that plasticizes the film.

Claims (35)

1. CLAIMS 1. An electrodepositable composition consisting of: (A) a cationic resin containing active hydrogen, electrodepositable on a cathode, consisting of: (1) a polyepoxide; (2) an oxygen-substituted diamine compound with a primary amine and a tertiary amine group, having the following formula: R1 / NH2- (CH2) nN \ R2 where n is an integer from 2 to 4 and where R1 or R2 are the same or different and are selected from the group consisting of: 1) R1 and R2, or both, which contain at least one oxygen and are alkyl, cycloalkyl, substituted alkyl or substituted cycloalkyl of 1 to 6 carbon atoms; 2) R1 and R2 are alkanol groups of 2 to 6 carbon atoms, and 3) R1 and R2 have from 1 to 6 carbon atoms and form a cyclic group with the N atom of the tertiary amine group, where any combination of amines is essentially free of polyoxyalkylene polyamine, and (B) isocyanate curing agent or at least partially blocked polyisocyanate, in an amount of from 5 to 60 weight percent of the resin solids.
2. 2. The electrodepositable composition of claim 1, wherein the oxygen-substituted diamine compound is selected from the group consisting of aminopropyldiethanolamine, aminopropylmorpholine and N- (2-aminoethyl) morpholine.
3. 3. The electrodepositable composition of claim 1, wherein the cationic resin containing active hydrogen further comprises a polycarboxylic acid.
4. 4. The electrodepositable composition of claim 3, wherein the polycarboxylic acid is a dicarboxylic acid.
5. 5. The electrodepositable composition of claim 4, wherein the dicarboxylic acid is a reaction product of a diol and an anhydride.
6. 6. The electrodepositable composition of claim 5, wherein the diol is the reaction product of bisphenol A and ethylene oxide and the anhydride is hexahydrophthalic anhydride.
7. The electrodepositable composition of claim 3, wherein the amount of polycarboxylic acid extends the polyepoxide chain and is sufficient to provide 0.05 to 0.6 acid groups per epoxide group.
8. The electrodepositable composition of claim 1, wherein the cationic resin containing active hydrogen further consists of an additional amine selected from the group consisting of secondary amines, non-hydroxy containing amines and amines with a ring structure, where up to 70 percent NH equivalents of the reagents for the electrodepositable cationic resin are supplied by the additional amine and 30 to 100 percent of the NH equivalents of the reactants for the electrodepositable cationic resin are supplied by the oxygen-substituted diamine compound.
9. The electrodepositable composition of claim 8, wherein 20 to 50 percent of the NH equivalents of the reagents are supplied by the additional amine and 50 to 80 percent of the NH equivalents of the reagents are supplied by the oxygen-substituted diamine compound.
10. The electrodepositable composition of claim 9, wherein from 20 to 30 percent of the NH equivalents of the reagents are supplied by the additional amine and from 70 to 80 percent of the NH equivalents of the reagents are supplied by the oxygen-substituted diamine compound.
11. The electrodepositable composition of claim 8, wherein the amount of oxygen-substituted diamine and the additional amine is sufficient for the cationic resin to have 0.1 to 3.0 milliequivalents of cationic group per gram of resin solids of the electrodepositable cationic resin.
12. The composition of claim 1, wherein the polyepoxide is the reaction product of a polyglycidyl ether of a polyhydric alcohol and the equivalent ratio of the epoxy groups to the polyhydric alcohol is from 1: 0.75 to 1: 2.
13. 13. The electrodepositable composition of claim 1, wherein the at least partially blocked isocyanate is polyisocyanate, present in the cationic resin containing active hydrogen such that there are 0.1 to 1.2 capped isocyanate groups for each active hydrogen of the hydroxyl and primary and secondary amino groups of the cationic resin.
14. 14. The electrodepositable composition of claim 1, which additionally contains at least one pigment.
15. 15. The electrodepositable composition of claim 1, which is substantially free of lead.
16. 16. The electrodepositable composition of claim 1, further comprising cationic microgels.
17. 17. The electrodepositable composition of claim 1, wherein the cationic resin containing active hydrogen consists of: (1) a polyepoxide; (2) an oxygen-substituted diamine compound selected from the group consisting of aminopro pildiethanolamine, aminopropylmorpholine and N- (2-aminoethyl) morpholine; (3) an additional amine selected from the group consisting of secondary amines, non-hydroxy containing amines and amines with a ring structure, where up to 70 percent of the NH equivalents of the reagents for the electrodepositable cationic resin are supplied by the additional amine and from 30 to 100 percent of the NH equivalents of the reagents for the electrodepositable cationic resin are supplied by the oxygen-substituted diamine compound; (4) a polycarboxylic acid, and (5) isocyanate curing agent at least partially blocked, wherein the isocyanate curing agent at least partially blocked from (B) is part of the cationic resin containing active hydrogen.
18. 18. The electrodepositable composition of claim 1, which is essentially free of polyoxyalkylene polyamine.
19. 19. A method of producing a cationic resin composition containing active hydrogen, electrodepositable on a cathode, consisting of: (a) mixing together, in a suitable reaction vessel, a polyepoxide, or the etherification precursors of poly phenols - hydrocarbons with epihalohydrin or dihalohydrin, and an isocyanate or at least partially blocked polyisocyanate curing agent, wherein this curing agent is present in an amount of 5 to 60 weight percent resin solids; (b) adding to the mixture of (a) a basic catalyst and an oxygen-substituted diamine compound with a primary amine group and a tertiary amine having the following formula: R1 / NH2- (CH2) nN R2 where n is an integer from 2 to 4 and where R1 or R2 are the same or different and are selected from the group consisting of: 1) R1 and R2, or both, which contain at least one oxygen and are alkyl, cycloalkyl, substituted alkyl or substituted cycloalkyl of 1 to 6 carbon atoms; 2) R1 and R2 are alkanol groups of 2 to 6 carbon atoms, and 3) R1 and R2 have from 1 to 6 carbon atoms and form a cyclic group with the N atom of the tertiary amine group, where any combination of amines is essentially free of polyoxyalkylene polyamine; (c) polymerizing said mixture of (b) to form a resinous composition, and (d) neutralizing the resinous composition of (c) by adding the resinous composition to a diluted mixture of acid and water to form a dispersed aqueous cationic resin electrodepositable on a cathode The method of claim 19, wherein, in the addition step (b), the addition of the oxygen-substituted diamine compound is a compound selected from the group consisting of aminopropyldiethanolamine, aminopropylmorpholine and N- (2-aminoethyl) morpholine . The method of claim 19, wherein the mixing step (a) further includes a polycarboxylic acid. 22. The method of claim 21, wherein the mixing step (a) has the polycarboxylic acid, which is a dicarboxylic acid. The method of claim 22, wherein the mixing step (a) has the dicarboxylic acid, which is a reaction product of a diol and an anhydride. The method of claim 23, wherein the mixing step (a) has the diol, which is the reaction product of bisphenol A and ethylene oxide and the anhydride is hexahydrophthalic anhydride. The method of claim 21, wherein, in the mixing step (a), the amount of polycarboxylic acid extends the polyepoxide chain and is sufficient to provide 0.05 to 0.6 acid groups per epoxide group. 26. The method of claim 19, wherein the step of addition (b) has a basic catalyst selected from the group consisting of: triphenylphosphine, ethyltriphenylphosphonium iodide, benzyldimethylamine, dimethylamino-cyclohexane, triethylamine, N-methylimidazole and hydroxide. tetrabutylammonium, in an effective catalytic amount. The method of claim 19, wherein the addition step (b) includes an additional amine selected from the group consisting of a secondary amine, amines that do not contain hydroxy and amines with a ring structure, where up to 70 percent of the NH equivalents of the reactants of the electrodepositable cationic resin are supplied by the additional amine and from 30 to 100 percent of the NH equivalents of the reactants are supplied by the oxygen-substituted diamine compound. The method of claim 27, wherein in the addition step (b), from 20 to 50 percent NH equivalents of the reactants are supplied by the additional amine and from 50 to 80 percent of the NH equivalents of the reactants are supplied by the oxygen-substituted diamine compound. 29. The method of claim 27, wherein, in the addition step (b), the amount of the oxygen-substituted diamine and the additional amine is sufficient for the cationic resin to have from 0.1 to 3.0 milliequivalents of cationic groups per gram of solids of Cationic electrodepositable resin resin containing active hydrogen. 30. The method of claim 19, wherein, in the mixing step (a), the polyepoxide is the product of the reaction of a polyglycidyl ether of a polyhydric alcohol and the equivalent ratio of the epoxy groups to the polyhydric alcohol is 1: 0.75 to 1: 2. The method of claim 19, wherein, in the mixing step (a), the at least partially blocked isocyanate is polyisocyanate, present in such a way that there are 0.1 to 1.2 isocyanate groups capped by each active hydrogen of the primary and secondary hydroxyl and amino groups of the cationic resin. 32. A substrate coated with an electrodepositable composition of claim 1. 33. The electrodepositable composition of claim 1, wherein the oxygen-substituted diamine, on a weight basis, is the predominant amine as an amine reactant for the polyepoxide to form the Epoxy and amine resinous adduct for the cationic resin containing active hydrogen. The method of claim 19, wherein the at least partially blocked isocyanate is added in an amount such that there is in the cationic resin containing active hydrogen from 0.1 to 1.2 isocyanate groups capped by each active hydrogen of the groups hydroxyl and primary and secondary amino of the cationic resin, to form an electrodepositable composition, and which includes the combination of the dispersed cationic resin and at least one pigment to form the electrodepositable composition, which is substantially free of added lead. 35. The electrodepositable composition of claim 1, which includes one or more catalysts, which are typically used in amounts of 0.05 to 5 percent by weight, based on the weight of the resin solids. SUMMARY An electrodepositable composition that has: (A) a cationic resin containing active hydrogen, electrodepositable on a cathode, having: (1) a polyepoxide; (2) an oxygen-substituted diamine compound having the following formula: R1 / NH2- (CH2) nN Formula I \ R2 where n is an integer from 2 to 4 and where R1 or R2 are the same or different and any of them , or both, contain at least one oxygen and are alkyl, cycloalkyl, substituted alkyl or substituted cycloalkyl of 1 to 6 carbon atoms, or R1 and R2 are alkanol groups of 2 to 6 carbon atoms, or R1, R2 and the atom of N form a cyclic group which is substituted or unsubstituted, such as morpholine and 1- (3-aminopropyl) imidazole, and (B) isocyanate curing agent or at least partially blocked polyisocyanate. The diamine compound of Formula I can be used alone or together with one or more secondary amines, amines that do not contain hydroxy groups and / or amines with ring structures. Optionally, the polyepoxide can be extended in its chain with compounds containing active hydrogen other than polyoxyalkylene polyamines. Also provided is a method of producing a cationic resin composition containing active hydrogen, electrodepositable on a cathode, consisting of (a) mixing together, in a suitable reaction vessel, a polyepoxide, or the precursors of the polyepoxide, an acid polycarboxylic acid and a blocked isocyanate curing agent; (b) adding to the mixture of (a) a basic catalyst and the diamine compound of Formula I; (c) polymerizing the mixture of (b) to form a resinous composition, and (d) neutralizing the resinous composition of (c) by adding the resinous composition to a diluted mixture of acid and water to form an aqueous dispersible cationic electrodepositable resin composition. .