CA2010820A1 - Cathodic electrocoat primer containing water insoluble organo-lead compounds as corrosion inhibitors - Google Patents

Abstract

ABSTRACT
Cathodic, aqueous, electrodepositable resin compositions containing organo-lead compositions. The organo-lead compositions comprise water insoluble lead salts of aliphatic acids having at least six carbon atoms or water insoluble lead salts of aromatic carboxylic acids.
The coating compositions, coating baths, coated articles and processes of this invention do not require lead pigments or soluble lead, yet the coatings have outstanding corrosion resistance. The use of the organo-lead compounds also eliminates the need for separate catalysts in the electrodeposition coating compositions, coating baths and processes.

Description

2 ~

Attorney's Docket oA~oDIc ~3CTRO~Oa~ PRI~E~ CONT~NI~ ~aTBR IN80 ~BL~
S oRoANo-LeAD COMPOUND8 ~ CORR08ION IN~IB$TOR8 Technical Field The field of art to which this invention pertains is electrodepositable resin compo~itions and, more specifically, electrodepositable resin compositions containing cross-linking agent~ for use in cathodic electrodeposition coating processes.

~kgroun~ o~ t~ v-nt~o~ -The electrodeposition of aqueou3 cationic resin compositions onto conductive substrates i~ well known in the coating arts. It is standard operating practice among auto~obile manufactures to coat auto~obile frames and sheet metal with anti-corrosive, electrodeposited, cathodic, aqueous film-forming resin compositions which are cured to a hard, durable, protective coatings. ~he use of electrocoat primer coating~ has enabled automobile manufacturer~ to providQ extended warran~ies covering body corrosion. These electrocoat coatings are also used by manufactur~rs of various products includ~ng trucks, construction equipment, appliances, auto~obil¢ part~, etc.
In a typical cathodic electrodeposition process, an aqueous bath is prepared from a principal resin ~olution or emulsion and a pig~ent paste. The principal resin solution or ~ulsion typically compri3es an epoxy-a~ine resin adduct or ~n acrylic polymsr containing amine functional mono~ers which can bo ~alted wi~h an acid to solubili2e the prlncipal resin in water, and a cxossDlinking agent.
Typical cross-linking agents include the blocked polyisocyanates and am~noplast crosslinkers . The pigment paste typically compri~es a mixture of a ~pecifically d~signed and formulated epoxy-amin~ resin adduct (known as a grind resin), which has been ~alted with an acid, and a pigment. The grind resin and pig~ent are ground together 2 ~

to form a pigment paste. The pigment paste is mixed with the principal emulsion and distilled water at the coating site to form an aqueous coatirlg bath having the desired solids concentration. The aqueous coating bath is typically contained within ~n in~ulated tank having sufficient capacity to completely immerse all articles that will be coated therein. Additiv2s conventional in the art such as organic coalescent solvents may be added to the bath to improve coating characteristics.
10An article which is to be coated typically comprises an electrically conductive material. The ar~icle is connected to a direct current circuit to act as a cathode.
The tank contains an anode or serves, itsalf, as the anode of the DC circuit. When the ob~ct i~ immersed in the 15coating bath (contained within the coating tank), a flow of electricity acro~s the ob~ect causes the principal emul~ion and pigment pa~te to be depo~ited on the sur~aces of the article along with any additives. The article i3 typically remov~d from the bath when the desired thickness of film 20haa been depo~ited, after which the article i8 optionally washed with distilled water. ~he article having ~he deposited film i9 then typically placed in an oven where ; t~e film is cured to a smooth, hard, durable, cross-linked coating.
25Cathodic electrodepositable amine-epoxy resin adduct compositions, method~ of manufacturing these cathodic el~ctrodepo~itable resin compositions, aqueous cationic ol-ctrod~po-ition b~ths processes for the deposition of th-~- resin~ from a coating bath onto a conductive ob;ect 30ar dl~cloc0d in U.S. PaSent Nos. 3,984,299, 3,468,770, ~,116,900, 4,093,S94, 4,137,140, 4,104,147, 4,22S,478, 4,419,467, and 4~l432,850, 4,575,523, and 4,57S,524, which ars incorporat~d by re~er~nce. Cathodic, electrodeposition acrylic resin composition~, methods o~ manufacture, aqueous 3Scationic coating bath~, and nethods o~ el~ctrcdeposition of these compositions are disclosed in U. S. Patent Nos.

3,883,483 and 3,853,803 which are incorpor~ted by 2 ~ 2 0 reference.
Cathodic electrodepositable resin coatings, also known as "Electrocoats" or "E-Coats, n provide a metal substrate with ~ superior corrosion-re~istant primer coating. It is S known that cationic E-Coats provide superior protection to a steel substrate in comparison to anodic resin compositions. In th~ automotive industry, these coatings are typically overcoated with a decorative and protective multi-layer top coating such as the industry'~ standard inner base coat and 8 clear outer top coat coating sy~tem.
It i~ th~ practice in the art to include lead pigments in electrocoat coating bath~, typically lead silicate and lead ~ilico-chromate and/or lead chromate. The lead is believed to serve as an anticorrosive agent. It is deposited with the cathodic E-Coat and enhances the corr~ion inhibiting characteristic~ of the E-Coat.
However, there are disadvantag~ presently a~sociat~d with the use of lead compound~ in cathodic electroco~t processe~. ~ir~t of all, lead compounds are typically introduc~d into E-Coat coatings baths through the inclusion of lead pigments in the coating baths. The lead pigments tend to settle out and foul bath tanks, piping, pumps, filters and associated equipment.
S~tting o~ lead pigment results in dirt in electrodepos~tabl~ films and also results in sludge accumulations in tank~ and proce~s equipment. This sludge mu~t be disposed o~ as a wast~ material. Ther~ hav~ been att-~pts to rQmove lead pigments from coating baths.
Cat~odic coating baths containing soluble lead salts are di-closed in U.S. Patent No. 4,115,226. The level of ~oluble lead ~alts such as lead acetate and lead lactate is difficult to control in a coating bath containing soluble lead. Typically exce~sive levels of water-borne lead are pr~sQnt producing higher ~han acceptable conductivity, resulting in inad~quate coating bath throw power and unacceptablQ coatings. In addit$on~ lead pigments c~nnot be introduced into a coating bath as a dry 2~ 3 ~20 pigment. They must be ground with specially de~igned and formulated E-Coat grind resins to for~ lead additiYe pastes or lead-containing pigment pastes. The lead-additive pa~te~ are ~hen added to the cathodic E-Coat coating baths.
The gxinding process is typically a dusty operation and extensive environmental controls are necessary to prevent workers from exposure to airborne lead particulates.
A tin catalyst 6uch as dibutyl tin oxide is typically added to an agueous cathodic electrodeposition coating bath to catalyze the cro~-linking reaction. The catalyst is a dry powder which mu~t be added to the E-Coat coating bath a~ p~rt of a pigment paste. The catalyst i extre~ely difficult to grind and dispers2 in a pigment paste. In addition, the cataly t is dif~icult to maintain in suspension in ths aqueous C08ting bath and tends to ~ettle out. 'Tin catalysts of the liquid type such as dibutyl tin dilaurata are 5U pected a8 crater causing agents.
What i~ needed in thi~ are cathodic electrocoat coating cOmpOBitiOn~ coating baths and methods of coating which do not require solid lead pigments, water soluble lead compounds, or tin catalyst~.

Dl-olo-ur- of th- Inv-~tio~
Novel agu~ou~ cathodlc~ electrodQpo~itable resinous coating compo~ition~ are di~clo3ed. The coating compo~ition~ co~pris~ an electrodepo~itAbl~ principal re in co~position, ~ cros~-linking agent, and an organolead co~pound co~pri~ing ~ water in~oluble lead salt of an aliph~tic acid having at least six carbon ato~ or a water in-olublo lead salt of an aro~tic carboxyl~c acid. As used throughout thi~ disclosure and the appended clai~s, the t-rm n insolublQ le~d ~alt~ denote~ lead salt~ that pos8e~8 solubilities of 0.05 p~rt~ or le88 per 100 parts of water at 2S-C. The coating compo~itions, when deposited as a ~ilm on a conductive substrate in an aqueous, cathodic electrodepo~ition process, and cured to a hard, durable coating, have excellent corrosion re~istance without the need for lead pigments or tin catalysts~
Another aspect of the present invention i~ an article coated with an aqueous, cathodic electrodepositable principal resinous coating composition. The coating composition comprises an electrodepositable principal resin composition, a cross-linking agent, and an organo-lead compound compri3ing a water insoluble lead ~alt of an aliphatic acid having at lea~t 6 carbon atoms or a water insoluble lead salt o~ an aromatic carboxylic acid. The coating composition when deposited as ~ film onto the article in a cathodic electrodeposition process has excellent corrosion re~istance without the need for lead pigment~ or tin catalysts.
Yet another aspect of the present invention is an aqueous, cathodic electrodeposition coa~ing bath. The coating bath comprises an acid-salted cathodic, electrodepo~itable principal resin composition, a cros~-linking agent, and an organo-lead compound comprising a water insoluble salt of an aliphatic acid having at least 2 0 5iX carbon atoms or a water in~oluble alt of an aromatic carboxylic ac$d. A coating electrodepo~ited from the bath onto a substrate and cured to a hard, durable, film has excellent corrosion resistance without the need for lead pigments or tin catalysts.
Yet another aspect of the present invention i~ an improved 2ethod of cathodic electrodeposition of agueous coating co~po~itions. The method compri~es forming an agu-ou~, cathodic electrodepositio~ coating bath wherein th~ ooating bath compri~es an agueous, cationic ~l-ctrodepo6itable princip~l resin composition and a cross-linking ~gent. The bath i8 contained in an ~lectrically in~ulated vess~l containing an anode. Then an~electrically conductive article, connected to an electric circuit to act a3 a cathode, is immersed in the bath and ~ufficient electrical power i8 caused to flow across the article so that a film of coating co~position i~ deposited on the surfaces of the article. Then the article is removed from 2 ~

the coating bath and the film is cured to a hard, durable coating. The improvement comprises including at least one organo-lead compound in the coating bath. The organo-lead compound comprises a water insoluble lead salt of an aliphatic acid containing at least six carbon atoms or a water insoluble lead salt of an ~romatic, carboxylic acid.
The resulting coatings containing the organo-lead compounds have excellent corrosion resistance and cure to hard, durable coatings without the need for lead pigments or tin catalysts.
The foregoing, and other features and advant~ges of the present invention will become more apparent from the following description.

~B8T ~OD8 FOR CARRYlN~ O~T T~ NTION
'The organo-lead compound~ of the present invention includa the water in~oluble lead salts of aliphatic acids having at least six carbon atoms and water insoluble lead salts of arom~tic carboxylic acids. The lead compounds may be liquid~ or they may be solids which are ~oluble in organic medium or solids which form liguid like pastes when mixed with a suitable organic medium, such ~8 a solvent or oil. Particularly preferred le~d ~alts include lead 2-ethyl hexanoate, lead naphthenate, lead octanaote, lead stearate, lead dodeconoate, and lead ol~ate.
Uæ~ul blocked polyisocyanates for use in the coating compo~ition~ of the present invention a~ cross-linking ag~nt~ lncludQ those which are stabl~ ln the dispersion ~yst~u~ at ordinary room te~perature and which react with tho resinous product of this invention at elevated temperatures~
In the preparation of the bloc~ed organic polyisocyanates, any ~uitable organic polyisocyanate can be u~ed. R~pre~ent~tive example~ are the aliphatic compounds such as trimethylene, tetra~ethyl~n~, pentamethylene, hexamethylene, 1,2-propylene, 1,2-butylene, and 1,3-butylene diisocyanates; 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanat~; the aromatic compounds such as ~ phenylene, p-phenylene, 4,4'-diphenyl, and 1,4-xylylene diisocyanates; the triisocyanates ~uch as tr$phenyl methane-4,4'4'-triisocyanate, 1,3,5-benzene triisocyanate and 2,4,6-toluene triisocyanate: and the tetraisocyanates such as 4,4~-diphenyldimethyl methane-2,2',5,5'-tetraisocyanate: the polymerized polyisocyanates such as toluene diisocyanate dimers and trimers, polymethylenepolyphenylene polyisocyanates having -N=C=o functionalitie6 o~ 2 to 3, and the lik~.
In addition, the orgznic polyi~ocyanate can be a prepolymer derived ~rom a polyol such as glycol~, e.g.
ethylene glycol and propylene glycsl, a~ well as other polyol~ ~uch as glycerol, trimethylolpropan~, hexanetriol, pentaerythritol, and the like, as w~ll as monoethers, such 2S d~ethylene glycol, tripropylene glycol and the like and polyothers, i.e., alkylene oxide condensates o~ the above.
A~ong the alkyl~ne oxides that ~ay be condensed with these polyolY to form polyethers are ethylene oxide, propylene oxide, butyl~n~ oxide, ~tyrene oxide and the like. These are generally called hydroxy-terminated polyether~ and can ~e lin~ar or branched. ~specially preferr~d are polyols such a~ ethylen~ glycol, diethylene glycol, triethylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, 1,6-hexan~diol, and the mixture~; glyc~rol, trimethylolethane,tri~ethylolpropane, 1,2,6-hexanetriol, pentaerythritol.
d~penta~rythritol,tripentaerythritol,polypentaerythritol, sorbltol, ~thyl gluco~ide~, sucro~ and the lik~ with alkylon~ oxide3 ~uch a3 ethyl~ne oxide, propylen~ oxide, th~lr ~lYtur~, and the like.
Particularly pre~erred polyisoGyanate~ include the re ction product of toluene diisocyanatQ and trimethylol propan¢ and, the i~ocyanurate of h~xam~hyle~e diisocyana~
~trimer of 1,6-hexamethylene diisocyanate).
Th~ blocking ag~nts wh~ch c~n be u6Qd to block the polyisocyanat~s and polyether polyol polyisocyanat~ adducts are thosQ known ~n the art. Any suitable aliphatic, ~ ~ 9 ~

cycloaliphatic, aromatic, alX:yl monoalcohol and phenolic compounds and secondary amine compounds can be used as a blocking agent in the practice of the pre~ent invention, including lower aliphatic alcohol~, such as methyl, ethyl, chloroethyl, propyl, butyl, amyl, hexyl, heptyl, octyl, nonyl, 3,3,5-trimethylhexyl, decyl and lauryl alcohols, and the like; the aromatic-alkyl alcohols such as phenylcarbinol, the monoethyl, monobutyl and monopropyl ethers of ethylene glycol and the like; the phenolic compounds such a~ phenol itself, substituted phenol~ in which the substitusnt~ do not adversaly affect the coating operations. Example~ of the latter includa cresol, nitrophenol, chlorophenol tertiary butyl phenol, secondary amines such as dibutyl amine, and hydroxy containing ester~.
Preferred blocking agents include the monopropyl ether of ethylene glycol and dibutyl amine. Additional blocking agents include tertiary hydroxyl amines, such as diethylethanolamine and oxim~, such a~ methylethyl ketoxime, acetone oxime and cycloh~xanone oxime, and caprolactam. ~nother preferred oxime is me~hyl-n-amyl ketoxime.
The ca~hodic electrodepositable principal resin compositions of this invention comprise epoxy re~ins which are reacted with amines to form adducts, and amine functional acrylic copolymers. The epoxy resins may be optionally chain extended resulting in an increa~e in the mol~cular wolght o~ the epoxy molecule~ by reacting with w~tor ~i~c$bl2 or water 801ubl~ polyol~.
The epoxid¢s use~ul in the practice of thi~ invention are ~he polyepoxides typically u~ed in this art and compris~ a resinous material containing at least one epoxy group per molecule.
The aminoplast crosslinking agents useful in the practice of th~ present invention include: alkylated melamine-formaldehyde resins, including ~uch melamine-formaldehyde resin~ which are characterized a~ being one o~

2 ~

the following types highly methylated, partially methylated and containing methylol functionality, methylated and containing imino functionality, highly butylated, partially butylated and containing methylol functionality, butylated and contalning imino functionality, mix~d methylated/butylated, mixed methylated/butylated contain~ng methylol functionality, mixed methylated/butylated and containing imino functionality, cr such other melamines as could be envisioned by exhaustiv~ or partial etherif~cation with an alcohol o~ the reaction product of 106 moles of formaldehyde for every mole of melamine ~xamples of suitable melamine-for~aldehyde resins which are commercially available include Cymel- 300, Cymel~ 301, Cymel- 303, Cymel- 350, Cy~el 323, Cymel 325, Cymel- 327, Cymel~ 370, Cymel~ 373, Cymel- 380, Cymel- 385, ~ymel-1116, Cym~l- 1130, Cymel~ 1133, Cymel 1168, Cymel~ 1156, Cymel- 1158, from tha American Cyanamid Company (Plastics Division, WallingPord, CT 06492), ~nd Resi~ene- 891, Resimene- 882, Re~im~ne~ 881, ~esimene- 879, ~esimena- 876, Resimene- 875, Resimene- 872, Resimen~ 747, Resi~ene 746, Re~imene- 745, Re~imene- 741, Resimsne- 740, Resimene~ 735, Re~imene- 731, Re~im~ne- 730, Resimene 717, RQsimene- 714, Resimene- 712, Resimene- 764, Resimene- 755, Re~imene~ 753, ResimenQ- 750, fro~ the Monsanto Company (St ~oui~, M0 63166) The aminoplast ~rosslinking agent~ that are useful in the practice o~ the present invention al~o include ~on~oguanamlne-~ormaldehyde re~lns which have been parti~lly or rully eth~rified with a suitable alcohol, typic~lly mQth~nol or butanol or a mixture ~hereof, and which may also contain m2thylol function~lity and/or imino functionality An example of this type of-cro~slinking agent would include the commercial product Cym81- 1123 from the A~erican Cyanamid Co~pany The ~minopla~t cro~slinking agent~ that are use~ul in the practice of this invention also include glycoluril-formaldehyde resins ~hlch have been partially or fully etherified with a suitable alcohol, typically methan31 or butanol or a mixture thereof, and which msy also contain methylol functionality and/or imino functionality.
Examples of commercially available croæslinking agents of this type include Cymel- 1170, Cy~el- 1171, and Cymel~ 1172 from the American Cyanamid Company.
The aminoplast crocslinking agents that are useful in the practice of this invention also include urea-for~aldehyde resins which have been partially or fully etheri~ied with a suitabl~ alcohol, typically methanol or butanol, and which may also contain methylol functionality and/or imino functionality. Ex~mples of commercially available cro~slinking agent of thi~ type include Beetle 5S, Beetle- 60, Beetle- 65, and Beetlee 80 from the American Cyanamid Comp~ny and Resimene- 960, Re imene~ 975, Resi~ene- 970, Resimene- 955, Re~imene~ 933, Resimene~ 920, Resimene- 918, Resimene~ 915, Re~imene 907, Reaimene- 901, Resimene- 980, fro~ the Monsanto Company.
The aminoplast crosslinking agent~ that are useful in the practice of thi3 inv~ntion al~o include carboxyl modified aminopla~t r~sin. These crosslinking ag~nt~ would include~elamine~formaldehyde,benzoguanamine-formaldehyde, glycolurilfor~aldehyde, and ure~-formaldehyde type crosslinking agents that include carboxylic acid functionality a~ well ~5 ~lkoxymethyl f~nctionality, typically ~ethoxym~thyl, ethoxymethyl, and butoxymethyl, or a mixture therQof, and which may ~180 contain methylol functionality and/or imino ~unctionality. Examples of co~ercially zvailable cro~linking agents of thi~ type in~lud~ Cymel- 1141 and Cy~el- 1125 from the A~rican Cyana~id Company.
A particularly useful cla~s of polyepox~de are the glycidyl polyethers of polyhydric phenols. Such polyepoxide resin~ are derived ~rom an epihalohydrin and a dihydric phenol ~nd have an spoxide equivalent weiqht (EEW) of about 400 to about 4,000. Examples of epihalohydrins are epichlorohydrin, epibromohydrin and epiiodohydrin with 3 2 ~
epichlorohydrin, epibromohydrin and epiiodohydrin with epichlorohydrin being preferred. Dihydric phenols are exemplified by resorcinol, hydroquinone, p,p'-dihydroxy-diphenylpropane (or bisphenol A as it is commonly called), p,p'-dihydroxybenzophenone, p,p'dihydroxydiphenylethane, bis- ( 2 -hydroxynaphthyl)methane, 1,5-dihydroxynaphthylene and the like, with bi phenol A being preferred. These polyepoxide resin~ are well known in the art and are made in desired molecular weight by reacting the epihalohydrin and the dihydric phenol in various ratioc or by reacting a dlhydric phenol in various ratios or by reacting a dihydric phenol with a lower molecular weight polyepoxids resin.
Particularly preferred polyepoxide resins are glycidyl polyethers of bi~phenol A having epoxida equivalent weights of about 450 to about 2,000, ~ore typically about 800 to abou~ 1,600, and preferable about 800 to about 1,500.
The polyepoxides used in the practice of this invention will have a relatively high ~olscular weight, that i~, typically about 1,600 to about 3,200, and preferably ~bout 1,600 to about 2,80Q.
Another quite useful clas~ of polyepoxides are produced si~ilarly from novolak re~ins or similar polyphenol resin~.
Also ~uitable are the polyepoxide~ comprising similar polygly~idyl ether~ of polyhydric alcohol-q which may be deriv~d from ~uch polyhydric alcohols as ethylene glycol, diethylenQ glycol, triethylene glycol, 1,2-propylene glycol, 1,4-propylene glycol, 1,5-pentanediol, 1,2,6-hexanatriol, glycerol, bis-(4-hydroxycyclohexyl)-2,2-prop~ne and tho like. There can ~l~o be u~ed polyglycidyl e~ter~ of polycarboxylic acid~, w~ich are produced by the re~ction of epichlorohydrin or similar epoxy compound~ with an aliphatic or aromatic polycarboxylic acid terephthalic acid, 2,~,-naphthalenedicarbocylic acid, dimerized linolenic ~cid and the like. Examples re glyeidyl adipate and glycidyl phthalate. Also useful are polyepoxides derived fro~ the epoxidation of an olefinically unsaturated ~a ~ ~2~

- alicyclic co~pound. Included are diepoxides comprising in part one or more monoepoxides. These polyepoxides are nonph~nolic and are obtained by the epoxidation of alicyclic olefins. For exa~ple, by oxygen and selected method catalysts, by perbenzoic acids, by acetaldehyde monoperacetate, or by peracetic acid. A~ong such polyepoxides are the epoxy alicyclic ethers and esters which are well known in th~ art.
Other ~poxy-containing compounds and resin~ include nitrogenous diepoxides such a3 disclosed in U.S. Patent No.
- 3,365,471; epoxy resin~ from l,l-methylene bis-(5-cubstituted hydantoin), U.S. Patent No. 3,391,0S7; bis-imide containing diepoxidesl U.S. Patent No. 3,45,711;
epoxyl~ted aminomethyldiphenyl oxides, U.S. Patent No.
3,312,664; heterocyclic ~,M'-d~glycidyl compound~, U.S.
Pate~t No. 3,503,979: amino epoxy phosphonate~, Briti~h Patent No. 1,172,916; 1,3,5-triglycidyl i~ocyanurates, as well a~ other epoxy-containing materials known in the art.
Any cationic, epoxy-a~ine resin adducts, a~ well as cationic epoxy amin~ re~in adducts conventionally known and used in the cathodic electrodeposition art~, can b~ u~ed in the practice of the present invention including modified epoxy resins adduct~. For ex~mple, the modified epoxy resins u~ed in ~he practic~ of this invention ~ay comprise one of the aforementioned epoxy resin co~pos~tions chain extended with wat~r mi~cible or w~er 801uble polyol, reacted with oxce~s amine, and finally react~d with a fatty acid or aliphatic monoepoxide. The~e epoxy amine resin adduot compo~itions are disclosed in U.S. Pa~ent Nos.

4,575,523 and 4,575,524, the di~clo~ur~ o~ which are incorporat~d by refarence. However, any epoxy-a~ine resin adducts produc~d by method known in the art, such AS by the diketimine Method a~ disclosed in U.S. Patent No. 3947339, - and other m~thods ~ay be used in th~ practice of the present ~nvention.
The polyamines used in the practice of this invention to form epoxy-amine resin adducts when an "~xce3~-a~ine"

prOCe~B i8 used are typical of those known in the art such as the polyamines disclosed in U.S. Patent No. 4,139,510, whic~ is inrorporated by reference.
The amine-~unctional acrylic copolymer~ useful in the 5practice o~ the present invention include copolymers of two or ~ore of the monomers such a~ hydroxy ethyl acrylate, dimethyl ethyl amino methacrylate, dimethylethylamino ~ethacrylate, styren~, butyl acrylate, ethyl acrylate and other monomers typically used to form acrylic copolymer 10resins. The copolymer resins will compris~ copoly~ers of esters of methacrylic acid, ~ unsaturated monomer~ such as styr~ne, hydroxyl functional e~ters of acrylic acid or methacrylic acid and an amine-functional ~ unsaturated monomer, or copolymer~ of glycidyl methacrylate or acrylate 15reacted with an a~ine. Cathodir, ~lectrod~positable amine-~unc~ional acrylic compositions ar~ disclos~d in U.S.
Patent No. 3,~83,483 which is incorporated by reference.
Suficient guant~ti~s of block~d polyisocyanate or aminopla~t cross-linking agents are incorporated into the 20electrodepo~itable coating compositions of this invention such that the deposited coating will be compl~tely cured upon baking. Also, th~ coating compo~ition~ will be designQd ~o that there will be no free isocyanate groups remaining aftar curing when using polyisocyanate cro s-25linking agent~.
Typically, about 10 wt.% to about 60 wt.t o~ blocked polyi~ocyan~tQ i~ incorporated based upon the total weight oS the princip~l r~in composition and ¢ros~-linking agent, ~or typically ~bout 20 wt.% ~o about 50 w~.~, preferably 30abcut 25 wt.% to about 35 wt.%. Typically about 10 wt~% to about 60 wt.% o~ the aminopla~t cros~-linXing agent i8 u~ed ba3ed upon the total weigh~ o~ the cro~s~ king agent and the principal re~in co~positions, pre~erably about 20 wt.%
to ~bout 40 wt.%.
35The blocked polyisocyanate~ o~ thi8 invention are mixed with the principal re~in co~po~itions, ~or exa~ple the epoxy-amine adduct or the amine-functional ~crylic ~ 3 ~

copolymer, by adding the blocked polyisocyanates to a ves~el containing the epoxy-a~in~ rQ~in adduct composition or the amine-functional acrylic copoly~er and mixing the charge for about one-half hour. Aminoplast cross-linking agents are typically added in a similar manner.
In oxder to solubilize or disperse into an emulsion cathodic electrodepositable resin conposition, it is necessary to salt the amine containin~ resin with a water soluble acid. The acid~ whlch can be used include tAose known in the art such a~ ~ormic ~cid, ~cetic acid, phosphoric acid, lactic acid, hydrochloric acid, etc.
Suf~icient quantities of the acid are ~ixed with the electrodepositable resin compo~ition~ to solubilize or disperse the resin composition in w~ter. One method, which is preferred, in whlch the salting process i~ accomplished i3 by, chaxging the resin composition, an acid, cosolvent~, water ~nd surfact~nts conventional in the art, into vessel, and ~ixing the ch~rge with a ~low spe~d mixer, . Typically, about 0.1 Meg to about 0.8 Meq of acid i~
used per gra~ of olid resin, mor~ typically about 0.2 Meq to about 0.7 ~Rq, and preferably about 0.2 Meq to about 0.5 Meq.
The principal resin ~olution or emulsion 18 typically incorporated directly into the coati~g b~h ~t the coating ~ite. Typically, a principal xesin solution or e~ulsion of the presQnt invention comprises about 10 wt.% about 90 wt.%
of amine-epoxy re~in adduct or amins func~ional acrylic re~in, ~or~ typ~cally about 20 wt.% to about 30.0 wt.~ and pr~-rably ~bout 22 ~t.%, although principal re~ins 30 solution or emulsions having higher or low~r concentrations ca~ b~ u~d.
Th~ concentration of cathodic, electrodepositable principal resin c~mpositions in an aqueou~, cat~odic electrodspo~ition coating bath i~ typi~ally ~bout 5 wt.%
to about 50 % wt.%, more typically a~out 10 wt.% to about 25 wt.%, ~nd preferably a~out 15 wt.%.
It should be noted that thc cathcdic, electro-2 ~
depositable resin coating compositions are typically shipped by the manufacturer to the user as a salted aqueous dispersion having a concentration of about 20 wt.% to about 36 wt.% of solids.
The cathodic electrodepositable coating baths of this invention are typically formed by mixing the solubilized (i.e., salted) cathodic electrodepositable resin compositions oP this invention in concentrate form with water, although un alted resin could be used in baths already containing the solubilizing acid. The electrodeposition bath may contain additional ingredients such as pigments, cosolvents, antioxidants, surfactants, etc., which are typically used in electrodeposition processes known in the art. Pigment compositions may be of any conventional type and are one or more of such piqments as tne iron oxides, dye, carbon black, titanium dioxide, talc, barium sulfate, barium yellow, cadmium red, chromic green, etc. Additionally, hydrophobic dyes as described in copending Patent Application Sarial No. (Attorney's Docket IN-1128) can be u~ed. Sufficient quantities of pigment are used to achieve the appearance charac~eristics desired such as gloss, reflectance, hue, tint and other desired characteristics. Typically, when using a pigment the amount of pig~ent in the coating bath is expressed in a ratio of total pigment to total binder. Typically a pigment to b$nder ratio of about 0.01 to about 0.95 is used in the electrodepositablo re~in compositions of the present invention, ~ore typically about 0.01 to about 0.4. Pigment is typically added to the electrodepo~ition bath in paste Por~, i.e., predisper~ed in a paste composition comprising pigment, cathodic, electrodepositable grind co~position and surfactants and additives conventional Sufficient quantitie~ of the water insoluble organo-lead compound~ of th~ present invention will be incorporated into the coating compositions of the present invention to provid~ sufficient corrosion resi~tance of the coated substrate. The organo-lead compounds may be 2 ~

incorporated into the principal resin solution or emulsion or into the pigment pa~te. When incorporated into the principal resin solution or emulsion or coating bath the weight percentage of water insoluble organo~lead to principal resin will typically be about 0.1 wt.% to about 10 wt.~, preferably about 0.5 wt.% to about 5.0 wt.% water insoluble organo-lead compounds are incorporated into a principal resin ox emulsion by mixing with the principal resin or princip~l r~sin/cros~linker ~ixture prior to salting and dispersing in water, ~imilarly, the water insoluble organo-lead co~pound3 are incorporated into the pigment paste by ~ixing with the grind resin prier to disper~ing into water.
The electrodeposition baths may contain coupling solvents which are water soluble or partially water soluble orga~ic solvent~ for the resinou~ vehicles used in the practice o~ thi~ invention. The coupling solvents or cosolvents used in the practice of thi~ invention are those typically used and known in the art.
The ~moothne88 of the cured coating i8 a function of the "flow~ of the depo~ited coating composition. Flow is defined a~ the tendency o~ the electrodepo~ited coating composition to liqui~y during the curing operation and form a smooth coh~Eive film over ths surfacQ o~ a coated article prior to the onsct cros~-linklng. T~i8 ~S accompli~hed in part by co-solvent3.
Exa~ple~ o~ such coupling ~olvents include ethylene glycol mono~ethyl ether, 2thyle~e glycol monoe~hyl ether, ethylen~ glycol ~onobutyl e~her, diethylene glycol monobutyl ether, ethanol, isopropanol, n-butanol, etc.
Suf~icient amounts of coupling ~olvent are optionally used so that a good ~u18~ on resulting in a ~EOO~h, deposited film i8 produced.
The alectrodeposition proce~ typicAlly take3 place in an Qlectrically insulated tAnk containing an electrically conductive anode whic~ iB attached to a direc~ current source. The ~ize of the tank will depend on the size of 2~ 5>2~

the article to be coated. Typically, the tank is con~tructed of stainlesc stee.l or mild teel and lined with a dielectric coating such as epoxy impregnated fiberglass or polypropylene. ~he electrocoat coating co~positions of thi~ invention are typically used to coa~ article~ such as automobile or truck bodie~, car parts, applications, etc.
The typical size of an electrodeposition bath tank used for this purpose c~n range from about several hundr~d to about 120,000 gallons. However, any electrically conductive article of any ~ize ranging from ~aRteners such a~ nuts and bolts to construction equipment to structural members may be coated with the E-Coat compositions of the present invention.
Typically, the article to be coated is connected to the direct current circuit so that the electrically conductive article act~ as the cathode. When the article is immersed in the coating bath, a flow of electricity across the articla result^~ in ~ film of the cationic elQctrodepositable coating co~position b~ing deposited on the surfaces of the article. The E-Coat composition ha a net positive charge and i8 therefore attracted to the negative cathodic ~ur~ace o~ the conductive article being coated. The thickness of the coating deposited upon the article during its re~idence in the cathodic E-Coat coating bath i~ a function of the cathod~c, electrodepositable E-Coat coating compo~ition, the voltage across the arti~le,l the curr~nt ~lux, the pH o~ the coating bath, the conductivity, thQ residence ti~e, etc. Sufficien~ voltage will ba appli~d to the articl~ for a ~ufficient time to obt~in a co~ting of su~ficient thickness and uniform cov-~ago. Typlcally, the voltage appli~d across tha coated art~cle i8 about 50 volt8 to about 500 volts, ~ore typically about 200 to ~bout 350 volt~, and preferably about 225 volts to about 3Q0. The current den~ity is typically about 0.5 ~mpere per ~q. ft. to about 30 a~per~s per 8q. ft., more typically about on~ ampere per sq. ~t. to about 25 ampere~ per sq. ft., and prefer~bly about one ampere per sq. ft. The article typically remains in the coating bath for a sufficient period of time to produ~e a co~ting or film of sllfficient thickne6s, having sufficient re~istance to corrosion. The residence time or holding ti~e i5 typically from about E~ few seconds to about a few seconds to about 3 minute, more typically about 1 minute to about 2-1/2 minutes, and preferably about 2 minutes;
however, this will vary and depend upon the previously mentioned parameters.
The pH of the coating bath is cufficient to produce a coating which will not rupture under the applied voltage.
That is, sufficient pH to maintain the stability of the coating bath ~o that the resin does not kick-out of the dispersed st~te and to control the conductivity of the bath. Typically, the pH iB about 4 to about 7 more typic'ally about 5 to about 6.8, and preferably about 5.5 to about 6.~.
The conductivity of the coating bath will be sufflcient to produ~e a coated film of ~ufficient thickness. Typically the conductivity will be about 800 micromhos to about 3,000 micro~ho~, more typically about 800 micromhos to 800 micromhos to ~bout 2,200 micromhos, and pr~ferably about 900 micromhos to about 1,800 micromhos.
The desirable coating thicknes~e~ are ~ufficient to provide r~istance to corro~ion while hav~ng adequate flexibility. Typlcally, the film th~cknes~e~ of the coated ob~ect~ of thi~ invention will be about 0.4 mil to about 1 8 ~il8 . Thinner or thicker fil~s ~ay be deposited as requir~d.
When the desired thicknes~ of the coating has ~een achi~v~d ths co~ted article i5 removed ~ro~ the electrodepo~ition bath and cured. Typically, the electrodepo~ited coating~ are cured in a conventional convection oven at a suf~cient temperature for a sufficient length of time to unblock the blocked polyisocyanate~ (when blocked polyisocyanates are used) and allow for cross-linking of the electrodepositable resin co~positions. Typically, the coated articles will be baked at a metal temperature of about 200'F (93rC) to about 600-F
(315~ ore typically ~bout 250-F ~121-C) to about 390-F
(l99-C), and preferably about 300-F (149-C) to about 375-F
(l91-C). The coated articles will be baked for a time period of about 10 minutes to about 40 minutes~ more typically about ten minutes to about 35 minutes, and preferably about 15 minutes to about 30 minutes. Once lo again, it will be appreciated by thos~ skilled in the art that times and temperatures will vary.
It is contemplated that the coated articles of the present invention may al~o be cured by using radiation, vapor curing, contact with heat transfer fluids, and equivalent methods.
~t will be appreciated by those skilled in the art that each of the coating parameters may vary according to the coating composition, bath characteristics, and the size and ~hape of the articles, coating perfor~ance requirements and the like.
Typic~lly the coated article~ of this invention will comprise conductive substrates such as metal, including st~Ql, aluminum, bras~, gold, silver, pl~tinum, nickel, chrome, zinc, coated ~teels, copper, and the like, however, any conductive sub~trate having ~ conductivity similar to the afore~entioned metal may be used. The articles to be coated ~ay comprise any sh pe ~o long a~ all surfaces can be wetted by the electrodeposit~on bath. T~e charact-~rt~tica o~ th~ arti~ls which have an effect on the coa~ing d~po~ition include the shape o~ th~ article, the capacity of the surface~ to be wetted by the coating, and the degree of shielding from the anode. Shielding is defined as the degree of interference with tha electromotive field produced between the cathode and the anode, thereby preventing the coating compo~ition from being deposited in ~hose shielded areas. A measure of the ability of the co~ting bath to coat remote areas of tha ob;ect is - 2 ~ 2 ~

throwpower. Throwpower is a function of the electrical configuration of the anode and cathode as well a~ the conductivity of the electrodepo~ition bath. High conductivity cause by ~oluble lead i~ known to decrease throw-power.
~ oluble lead compounds a8 described in US Patent 4,115,226 such lead aoetate or lead lactate tend to cause an increase in both t~ bath conductivity and the depo~ited film conductivity. Thi~ reduce~ the voltage at whioh the nrticle can ba coated without experiencing rupturing.
Rupturing i8 a coatlng defect which can re~emble film boiling or blowing, resulting in an unacceptable appearance and performance. The reduced rupture voltage i~ in part responsi~l4 for the reduced throwpower. The reduced voltaqe al80 may reduce the maximum film bu$1d obtained, whlc~ may re ult in poor coating performance.
The coating of the coated articl4s of thi~ invention exhibit ~uperior smoothness, glo~s, 1exibility, durabillty and resi~tance to corro~ion. Smoothness and glos~ are related to the flow Or the electrodeposited cathodic resin.
Durability, flexibility and resistance to corrosion are related to the chemical nature o~ the electrodeposited cathodic E-Coat co~positions a~ well a~ the smoothne~ of the depositRd coatings. Thes~ coating composition~ readily accept an auto~otive prlmer or an overcoat ~uch as the industry stand~rd inner pigmented ba~e coat 2nd outer clear top coat.
The aquoou~ E-Coat coating bath~ o~ the present invsntion do not contAin water ~oluble lead compound~, lead pignent~ or tin catalysts. Coating~ without w ter 801uble lead co~pounds, lead pigment~, or tin catalyst~ contain cro~slinkers o~ the blocked isocyanat~ typ~ d~ not cure to hard, solvent resi3tant, durable films having acceptable corrosion per~ormanc~. Surpri~ingly, water insoluble ~5 organo-lead compounds ~an be used in aqueous E-Cozt baths in place of water soluble lead co~pound~ ad pig~ents, or tin catalyst~, and pro~uc~ d~posit~d, cured coating which 3 2 ~

have hard, durable, soluble resistant films with ~xcellentcorro~ion resistance. ~lso surpri~ingly, water insoluble organo-lead compounds do not reduce the rupture voltage, decrea~e the throwpower, or lower the maximum film build obtain~ble.
It should be noted that t:he articles coated by the E-coat coating composition~ of this invention are typically automobile bodle~ which have been pretreated to remove impurities and contaminants in a phosphatizing bath, however, the coating compositions may be used to coat virtually any ob;ect comprising a conductive ~ubstrate whether pretreated, precoated or not.
The following examples are illu~trative of the principles and practice o~ this invention, although not limited thereto. Parts and percentages where used are part~ and percentages by weight.
R~P~ NTA~I~E ~SA~ O~ ~YPICAL ~O~YX$RIC NaT~RIAI8 ~8~L ~N ~ ~9~T~ON
~D~ 1 Ethyl cellosolve (290.0 parts by weight3 and 106,0 partY o~ butyl cellosolve are charged into a reactor equipped wi~h conden~er, ~tirrer, thermometer, and dropping ~unn~l. The mixturs is heated to 120--130-C a~d held at this tamperature. To this mixture i~ then added, over a period oP 3 hours, mixture oP 580.0 part~ butyl acrylate, 350.0 part~ atyr~ne, 140.0 parts N,~-dimethylaminoethyl ~etha~rylnte, 58.0 parts 2-hydroxyethyl methacrylate, and 17.0 part~ -azobisisobutyronitrile. A mixture of 2.0 part- t-butyl-pRroxyisopropyl carbonate and 1.5 parts ethyl celiosolv~ i~ then added. The reaction i8 h~ld at 120-C
for 1 hour, a~ter which a sacond ~ddition of said component~ i~ added and, likewise, the reaction is permitted to continue for 1 hour~, after which a third and final addition of said ~omponent~ i8 added and tho reaction iq permitted to continue for 2 hours.

2 ~ 2 ~

P~ ~
A reaction vessel is charged with 727.6 part~ Epon 829, 268.1 parts PCP-0200, and 36.1 part~ xylene and heated with a nitrogen sparge to 210-C. The reaction is held at re1ux for about 1/2 hour to remove water. The reaction mixture is cooled to 150-C and 197.8 parts bisphenol A and 1.6 parts benzyldimethylamine catalyst are added and the reaction mixture heated to 150--190 C and held at this temp¢rature for about 1 1/2 hours and then cooled to 130-C.
Then 2.2 parts of the benzyldimethylamine cataly~t are added and the reaction ~ixture held at 130-C for 2 1/2 hours until a reduced Gardner-Holt viscosity (50 percent-resin solids solution in 2-ethoxyethanol) of P is obtained.
Then 73.1 parts of a diketimine derivative derived from diethylenetriamine and methyl isobutyl ketone (73 percent solld~ in methyl isobutyl ketone), and 39.1 parts N-methylethanola~ine are added ~nd the temperature of the reaction mixture is brought to 110~C and held at this temperature for 1 hour. To this ~ixture, 76.5 parts 2 hexoxyethanol are added.

B~A~Ph~ 3 To a clean dry reactor, 115 parts ~ylene are added.
The mix$n~ liquid i8 blanketed with pure nitroqen and heated to ~2 C. An addition of 568.1 parts of Epon~ lOOlF
- (EEW ~ 520 - 540) is ~ads at such a rat~ that the batch temperatura n~ver drops below 60'C, usually ov~r a period of two hours. Heating i~ continued until 100-C. At this point, 75.9 parts dodecyl phenol are added and heated to 118-C. Yacuum drying by di~tillation Or xylen~ i~ started at ~hi~ tQ~p~ratur~ and continued while h~ating to 125-C.
The pr2ssur~ should be between 65 cm and 69 c~ Hg (88 kP -92 kP) ~t full vacuum. The drying stag~ should take between 1.0 and 1.5 hours. Break vacuum with pure nitrogen only. The batch i8 cooled (the 8ampl8 at thi~ point should be 94.3-95.3 ~ non-volatiles) and at 115-C, 1.1 parts benzyldimethyla~ine are added. The peak exotherm 2 ~ 2 temperature should reach 129--132-C. The temperature is maintained at 128--132-C and t:he polymerization i5 followed by EEW titration. Every 30 minutes the reaction is sampled and i~ stopped at an end point of 1090-1110 EEW. The typical reaction time is three hours. Ad~ustments to the catalyst level may be neceassary if extension period deviates more than ~0 minutes from three hours. At the target EEW, 12.1 parts butyl cello~olve and 74~7 parts xylene are added ~ollswed by 42.6 parts DEOA (diethanol amine). The temperature of this reaction Rhsuld not exceed 132-C. Cooling may be neces~ary at thi~ point with jacket or coils. A vacuum suction is ~tarted im~ediately after the DEOA addition and pressure is reduced to 18 inches of Hg and held for 5 minutes. The pres~ure i8 further reduced in 2 inch Hg increments followed by short holding period until~ 26-2~ inch2s of Hg is achieved. The batch i3 then cooled to 90-C in one hour following addi~ion of DEOA. To achieve thi~, a good reflux rat~ should be attained in 20-25 minutes a~ter the DEOA addition. All ~olvents are returned to the raactor. A~ter one hour of vacuu~ cooling (T ~ 90-C), 40.6 part~ ethylene glycol monohexyl ether and 107.7 parts isobutanol ar~ added without breaking vacuum.
Th~ batch is cooled for 35 mlnutes to 57--61- C under full vacuum to achieve the target temperature during the specified time t~bles. After the 35 m$nute cooling period, 13.3 parts Or di~ethylamino propyl~mine (D~PA) are charged aa fn~t aY pos~ible. The batch i~ k~pt be~ween 54--60- C
for t~o hour~ ~fter the exotherm. Then it i~ heated to 90-C over one hour and thi~ temperature i~ held for one hour. The batch is then cooled to 80-C~

~A~ 4 To a suitablQ reactor, 1881.7 parts o~ triethylene tetramine are added. ~eat and agitation i8 applied and, at 104-C, lg44.8 parts o~ an epoxide resin ~olution at 59.4%
solids in ethylene glycol monomethyl ether (the epoxide resin being glycidyl polyether of bisphenol A having an 2 ~ 2 epoxide equivalent weight of 895) are slowly added. The epoxide resin addition is co~pleted in 65 minutes and the te~perature drops to 99-C. The temperature is slowly raised to 121-C over 45 minutes and i8 held between 121~
127-C for 1 hour to complete the adducting reaction. The excess unreacted amine and the ~olvent is removed by heating the adduct solution to 232 C under vacuum (25 mm Hg pres~ure). When the distillation is completed, vacuum i8 released and the temperature is reduced to 182-C. This 0 i5 followed by the addition of 700 parts of ethylene glycol monome~hyl ether, which reduce~ the temperature to about 118'C. When the solution i~ homogeneou~, 458.3 parts of the glycidyl ether of mixed fatty alcohols containing predominantly n-octyl and n-decyl groups, the glycidyl ether having an epoxide equivalent weight of 229 are added at a,temperature of 107--116-C. Heating i~ stopped after an additional bour at 116-C. The resulting product should have a solids content of 71.3 %, and a Gardner-Holt viscosity of Z6 -Z7.
~XA~PL~ 5 A blocked isocyanate (polyurethane cros~-linking agent, reverse ordor) i8 prepared according to the following procedure. Slowly and with stirring in a nitrogan atmosphera, 291 parts of an 80/20 isomeric ~ixture of 2,4-/2,6-tolu~n~ d~isocyanate, 0.08 part~ of dibutyltin dilaurate and ~80 parts of methyl i~obutyl ke~one are ch~rgod to a ~uit~ble reactor, the temperature being malntained below 38-C. The mixture is m~intained at 38'C
for a ~urth~r half hour after which 75 parts of tri~cthylolpropana are added. Aft~r Allowing the reaction to proc~ed for about 10 hours, 175 parts of ethylene glycol monopropyl Qther are added ~nd the ~ixture reaction kept 1.5 hours at 121-C until essentially all the isocyanate groups are reacted. This depletion i8 recognized from the in~rared spectrum.
The normal order blocked isocyana~e can be prepared by 2 ~
the altering of the foregoing order of addition pursuant to Example 1 of Ger~an Offenlegungsschrift 2,701,002.

~A~P~ 6 A blocked i8 isocyanate crosslinker tpolyurea) is prepared according to the following procedure. To a dry reactor., 4B3 parts of triisocyanurated hexamethylene-diisocyanate and 193 parts of 2-hexanone are charged.
Dibutylamine (307 part~) i5 added slowly and with stirring under nitrogen atmospher~ so that the temperature does not exceed ~0-C. After all amine has reacted, 14 parts of n-butanol and 0.2 parts of dibutyl tin dilaurate are added.

~A~PL~ 7 A qua~ernizing agent for use in preparing a pigment grin~ resin is prepared by adding 320 parts 2-ethylhexanol half-capped toluene diisocyanate (95% solids in methyl isobutyl ketone) to 87.2 parts dimethylethanolamine in a suitable reactor at room temperature. The mixture is allowed to exotherm and i~ stirred for 1 hour at 80-C.
Lactic acid ~117.6 parts o~ 88% aqueou~ lactic acid solution) i8 then charged followed by the ~ddition of 39.2 parts 2-butoxyethanol. The reaction mixture is stirred for about 1 hour at 65-C. to form the desired quaternizing agent.
The gr$nd resin i8 prepared by ~harging 713 parts o~
Epon- 839 and 289.6 part8 of bi~phenol A to a suitable reaction ve8841 and heated to 150--160-C to initiate an exoth~rm. The re~ction mixture is per~itted to exotherm for 1 hour at 150--160-C. The reaction ~ixture is then cool~d to 85--90~C, homogenized and then charged with 71.2 parts deionized water followed by the addition of 496.3 parts of the above described quaternizing agents. The temperatur~ of the reaction mixture i8 held a~ 80--85-C
until an acid value of about 1 is obtained.

- 2 ~ 2 ~

Æ~AMPL~ 8 Into a reaction vessel, 27.81 parts of the diglycidyl ether o~ bisphenol A and 1.44 parts xylene are changed.
The charge i8 heated to 82-C under a dry nitrogen atmosphere. The heating i8 discontinued, and a charge of 5.81 parts bisphenol A is added, tcqether with 0.002 parts triphenyl phosphine catalyst. ~he heating of the reaction ves~el is then continued to a temperature o~ 127-C, where the reaction begin to exotherm on its own, with a peak of about 150~-160-C. The extension i8 held above 1~0-C until an EEW of 340 360 is achieved (about 345). Onc~ the target EEW is reached, 21.08 parts butyl cellosolve i8 added to the reaction vess~l and the reaction mixture i8 then cooled to 49-C. After a temperature of 49-C is achieved, a mixtur~ of 7.77 parts of 9-amino-3,6-dioxanonan-1-ol and 4.07 'part dimethylaminopropylamine are added to the reaction vessel over a period o~ 6 minutes, followed by a pump flush of 0.53 parts ethylene glycol monobutyl ether.
The batch exothar~s to 104--110-C, ~nd the reaction mixture i8 then held at or below 115-C for ona hour. Next, 4.92 parts butyl cello~olv2 are charged into the reaction vessel and the batch i8 cooled to 77-C. Next, 14.9 parts nonylphenolglycidyl ether are charged into the reaction vessel followed by a pump flush of 1.53 parts of ethylene glycol monobutyl ether. The batch exotherms to 88-~93-C, and th~ batch i~ then held at this temperature ~or one hour. Fin~lly, 10.03 parts butyl c~llosolve is charged into th~ reaction vefi3~1 and the batch cooled to 66-C. The r~sult~nt product is then filtered through 25 micron bags and dru~med.

~A~PL~8 OY T~J INCORPORA~IO~ O~ ~AT~R I~80~LR ORGANO-L~aD CO~O~o W IN ~NCIPAL R~8I~ ~OL~T~ON8 ~AK~LE 9 - ~5 This general procedure ~pplies to ~he examples 9 - 15.
Specific formulations for these examples are ~hown in Ta~le 1. All a~ounts shown in Table 1 represent the weight of 2 ~
the non-volatile portion.
Charge a suitable mixing ve~sel with the crosslinker.
Optionally, if a hydrophobic dye is included, the dye is add~d to the crosslinker with slow stirring, and i5 mixed for about 30 minutes. Plasticizer and organic solvents are then added to the mixture, c:ontinuing the slow agitation.
Principal resin, at 21--4!3-~, i3 then added to the continuously ~ixing batc~. ~fter 30 minutes of continuous stirring, the water insoluble organo-lead compound(s) is added. The ~ixing is continued uninterrupted for 30 minute~, then all remaining additive~, flow agents, solvent, antifoam agent~, and curfactants are added.
TABLE
~5 INGREDIENTS EXAMPLES
, 9 10 11 12 13 14 15 . ~
Crosslinker30.531.0 15.0 31.0 14.0 31.0 (Exa~ple 5) Crosslinker 15.0 14.0 (Example 6) Cymel- 1141 31.0 Paraplex~ 7.6 7.6 7.6 7.6 7.6 7.6 (Rohm & Haas) Orasol- RL 1.2 1.2 black dye Prin. resin 67.0 (Exampl~ 1) Prin. Rosin 57.3 (Exa~ple 2) Pr~n. re~in56.657.3 57.3 57.3 (ExaJple 3) Prin. resin 57~3 (Example 5) Lead (III) 1.8 1.8 1.8 1.8 2-ethyl hexanoate (42% Pb) Lead (III) 3.2 octanoate (24% Pb) 2 ~ 0 (Table 1 continued~
Lead naphth~nate 3.2 s(24% Pb) additive 2.3 2.3 2.3 2.3 2.3 2.3 ~A~PL~ OF I~CO~PORA~O~ 0~ R IN80~U~LÆ OR~ANO-~AD
CO~PO~N W ~TO ~RINCI~AL ~J~I~ ~W ~8IO~
~XAMF~B~ 1~ - 23 This g~neral procedure applies to examples 16 - 23.
The specific for~ulations ~or these examples are shown in Table 2.
First, principal resin solutions containing the crossl~nker, pla~ticizer, the organo-lead ~o~po~nd(s), and other applicable ingredient~ are ~ixed together as de~cribed for the pr~vious sQt o~ ~xa~ple3 (9 - 14). A
solubilizing acid is then added to the principal resin ~olution, and then th~ resultant solubilized principal resin ~olu~ion i8 then Dix~d with deionized wat~r, or op~ionally, a deionized water/surfactant ~ixtur~.

2 5 TAB~ 2 INGREDIENTS EXAMPLES

Exampl~ 9 269.7 (74% NV) Exampl~ 10 269.7 269.7 t74% NV) ~Ya-P1~ 1~ 269 . 7 (7~
EXA~P1~ 12 269.7 (74%-NV) Exa~pl~ 13 269.7 (74% NV) Example 14 269.7 (74% NV) Exa~ple 15 269.7 ~74% NV) 2 ~ 2 ~3 (Table 2 continued) ~cetic 2.53 2.53 2.53 3.19 2.92 3.31 2.53 Acid (Glacial) Lactic aoid 4.46 (85S) Deionized 298.0 298.0 296.1 298.0 ~97.3 297.6 297.2 298.0 water ~ AMPL~8 o~ PIOE~NT PA~B~, ~ITE AND ~IT~O~T T~E
INCoRPo~ATIO~ OF ~T~R I~80~WaL~ OR~N~L~AD COM~OUN~8 - ~AKPLE 2~
To a suitable mixing vessel, 198.3 parts of grind resin from Example 8 are mixed with 11.1 parts acetic acid, ~.O parts of Tristar~ 27 defoamer (Tristar Che~ical Co., Dall~s, TX), and 342.6 parta deionized water. Once homogeneous, 12.6 parts carbon black, 63.0 parts clay extender, and 329.7 parts titanium dioxide are dispersed into the mixture. Using a high speed Cowles disperser, sandmill, ballmill, or other pigment dispersinq eguipment, a finenese of gr~nd (F.O.G.) o~ 5-7 is obtained.

~AMPL$ 25 To a suitable mixing vessel, 226.36 of grind resin from Exa~ple 7 are mixed with 388.9 parts of deionized water, 16.54 parts carbon black, and 564.31 parts titanium dioxid~. Th~ mixture is ground until a Hegman fineness of grind o~ 5 - 7 i8 obtained.

~XU~L~ 26 . To a ~uitable mixins vessel, 198.3 parts of grind resin from Example 8 are mixed wi~h 27.2 parts of Lead-2-Ethylhexanoate, and stirred for about 30 minute~. Then, 11.1 parts acetic acid, 700 parts of Tristar 27- defoamer, and 342.6 parts deionized water are added, continuing the mixing. Once homogeneous, 12.6 parts carbon black, 63.0 parts clay extender, and 329.7 parts titanium dioxide are added and dispersed to a Hegman finene~s of grind of 5 - 7.

2 ~ 2 0 ~SA~LE OF C~T~ODIC' PAIN~8 CO~T~I~IN~
W~T~R IN80~L~ L~AD CO~PO~N W
~A~P~R8 27 - 3~
Example are prepared according to the formulations outlined in Table 3.

ING~EDIENTS EXAMPLE

Emul~ion (Example 16) 571.4 ` Emul~ion 400.7 (Example 1~) Emulsion 413.2 (Example 18) Emulsion 400~7 (Exa~ple 19) Emulsion 413.2 (Example 20) Emul ion 400 7 (Example 21) Emulsion (Example 22) Emulsion 571.4 400.2 (Example 23) Pzste 109.8 109.8 109.8 (Example 24) Paste 95.0 95.0 (Example 25) Paste 112.0 (Exa~ple 2~) Deionized 428.6 489.5 491.8 489.5 491.8 489.5 428.5 487.8 wator Total 1000 1003 1000 1000 1000 1000 1000 1000 Although this invention has beQn shown and described with respect to the detalled e~bodi~ents thereof, it will be under~tood by those skilled in the art ~hat various changes in form and detail ~hereo~ may be made without departing from the spirit and scope of this invention.

Claims (16)

1. An aqueous, cathodic, electrodepositable resinous coating composition comprising a cationic electrodepositable resin composition;
a cross linking agent; and an organo-lead compound comprising a water insoluble lead salt of an aliphatic acid having at least six carbon atoms or an insoluble lead salt of an aromatic carboxylic acid, which is either a liquid or which becomes a liquid solution on mixing with a suitable solvent or oil or which becomes a liquid-like paste on mixing with a suitable organic solvent or oil;

the composition when deposited as a film on a conductive substrate is an aqueous, cathodic electrodeposition process and when cured does not require any additional catalyst and cures to a hard, durable film having excellent corrosion resistance .

2. The coating composition of Claim 1 wherein the resin composition is selected from the group consisting of amine epoxy resin adducts and amine functional acrylic resins.

3. The coating composition of Claim 1 wherein the cross-linking agent is selected from the group consisting of blocked polyisocyanates, blocked polyether polyol polyisocyanate adducts, alkanol blocked melamine resins and alkanol blocked urea formaldehyde resins.

4. The coating composition of Claim 1 wherein the organo-lead compound is selected from the group consisting of lead 2-ethyl hexanoate, lead naphthenate, lead octanoate, lead dodecanoate, lead oleate, and lead stearate.

5. An article coated with an aqueous, cathodic electro-depositable resinous coating composition, wherein the coating composition comprises a cationic, electrodepositable resin composition;
a cross-linking agent; and a organo-lead composition comprising an insoluble lead salt of an aliphatic acid having at least six carbon atoms or an insvluble lead salt of an aromatic carboxylic acid;

the composition when deposited as a film on the article in cathodic electrodeposition process and cured to a hard, durable film has excellent corrosion resistance.

6. The article of Claim 5 wherein the resin composition is selected from the group consisting of amine epoxy resin adducts and amine functional acrylic resins.

7. The article of Claim 5 wherein the cross-linking agent is selected from the group consisting of blocked polyisocyanates, blocked polyether polyol polyisocyanate adducts, alkanol blocked melamine resins and alkanol bloced urea formaldehyde resins.

8. The article of Claim 5 wherein the organo-lead compound is selected from the group consisting of lead 2-ethyl hexanoate, lead naphthenate, lead octanoate and lead dodecanoate, lead oleate, lead stearate.

9. An aqueous, cathodic electrodeposition coating bath comprising a cationic electrodepositable resin composition;
a cross-linking agent; and a organo-lead composition comprising an insoluble lead salt of an aliphatic acid having at least six carbon atoms or an insoluble lead salt of an aromatic carboxylic acid;

coatings electrodeposited from the bath onto a substrate and curing to a hard, durable film having excellent corrosion resistance.

10. The coating bath of Claim 9 wherein the resin composition is selected from the group consisting of amine epoxy resin adducts and amine functional acrylic resins.

11. The coating bath of Claim 9 wherein the cross-linking agent is sslected from the group consisting of blocked polyisocyanates, blocked polyether polyol polyisocyanate adducts, alkanol blocked melamine resins and alkanol blockad urea formaldehyde resins.

12. The coating bath of Claim 9 wherein the organo-lead compound is selected from the group consisting of lead 2-ethyl hexanoate, lead naphthenate, lead octanoate, lead dodecanoate, lead oleate, and lead stearate.

13. In a method of cathodic electrodeposition of aqueous coating compositions comprising forming an aqueous cathodic electrodeposition coating bath, wherein the coating bath comprises an aqueous cationic, electrodepositable resin compositions and a cross-linking agent, said bath contained in an electrically insulated vessel containing an anode, then connecting a conductive article to an electrical circuit to act as a cathode and immersing the article in the bath, and causing sufficient power to flow across the article so that a film of coating composition is deposited upon the surfaces of the article to a sufficient thickness, then removing the article and curing the film to a hard, durable coating;

the improvement comprising including in the coating bath at least one organo-lead composition comprising an insoluble lead salt of an aliphatic acid having at least six carbon atoms an insoluble lead salt of an aromatic carboxylic acid, the resulting coating containing the organo-lead having excellent corrosion resistance.

14. The method of Claim 13 wherein the resin composition is selected from the group consisting of amine epoxy resin adducts and amine functional acrylic resins.

15. The method of Claim 13 wherein the cross-linking agent is selected from the group consisting of blocked polyisocyanates, blocked polyether polyol polyisocyanate adducts, alkanol blocked melamine resins and alkanol blocked urea formaldehyde resins.

16. The method of Claim 13 wherein the organo-lead compound is selected from the group consisting of lead 2-ethyl hexanoate, lead naphthenate, lead octanoate and lead dodecanoate, lead oleate, lead stearate.